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Sample records for beating rabbit atria

  1. Cardiac mast cells regulate myocyte ANP release via histamine H2 receptor in beating rabbit atria.

    PubMed

    Li, Dan; Wen, Jin Fu; Jin, Jing Yu; Quan, He Xiu; Cho, Kyung Woo

    2009-06-01

    It has been shown that histamine inhibits atrial natriuretic peptide (ANP) release. Because cardiac mast cells are the principal source of histamine in the heart, we hypothesized that cardiac mast cells are involved in the regulation of atrial ANP release. To test the hypothesis, experiments were performed in perfused beating rabbit atria allowing atrial pacing and measurements of changes in atrial stroke volume, intraatrial pulse pressure and myocyte ANP release. Mast cell degranulation with Compound 48/80 decreased atrial myocyte ANP release, and the response was blocked by a selective histamine H(2) receptor blocker, cimetidine, indicating that histamine was responsible for the decrease in ANP release. Mast cell stabilization with cromolyn blocked the Compound 48/80-induced decrease in ANP release. These data suggest that mast cell-derived histamine is involved in the regulation of cardiac ANP release. Thus, the cardiac mast cell-cardiomyocyte communication via the histamine-ANP pathway may implicate in the cardiac disorder associated with mast cell degranulation such as in acute coronary syndrome or cardiac hypertrophy. PMID:19328828

  2. cAMP induction by ouabain promotes endothelin-1 secretion via MAPK/ERK signaling in beating rabbit atria.

    PubMed

    Peng, Li-Qun; Li, Ping; Zhang, Qiu-Li; Hong, Lan; Liu, Li-Ping; Cui, Xun; Cui, Bai-Ri

    2016-01-01

    Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the Na(+)-K(+)-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain (3.0 µmol/L) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 (3.0 µmol/L), an inhibitor for reverse mode of Na(+)-Ca(2+) exchangers (NCX), but did not by L-type Ca(2+) channel blocker nifedipine (1.0 µmol/L) or protein kinase A (PKA) selective inhibitor H-89 (3.0 µmol/L). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline (100.0 µmol/L), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP (0.5 µmol/L) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 (30 µmol/L), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds. PMID:26807018

  3. cAMP induction by ouabain promotes endothelin-1 secretion via MAPK/ERK signaling in beating rabbit atria

    PubMed Central

    Peng, Li-qun; Li, Ping; Zhang, Qiu-li; Hong, Lan; Liu, Li-ping

    2016-01-01

    Adenosine 3',5'-cyclic monophosphate (cAMP) participates in the regulation of numerous cellular functions, including the Na+-K+-ATPase (sodium pump). Ouabain, used in the treatment of several heart diseases, is known to increase cAMP levels but its effects on the atrium are not understood. The aim of the present study was to examine the effect of ouabain on the regulation of atrial cAMP production and its roles in atrial endothelin-1 (ET-1) secretion in isolated perfused beating rabbit atria. Our results showed that ouabain (3.0 µmol/L) significantly increased atrial dynamics and cAMP levels during recovery period. The ouabain-increased atrial dynamics was blocked by KB-R7943 (3.0 µmol/L), an inhibitor for reverse mode of Na+-Ca2+ exchangers (NCX), but did not by L-type Ca2+ channel blocker nifedipine (1.0 µmol/L) or protein kinase A (PKA) selective inhibitor H-89 (3.0 µmol/L). Ouabain also enhanced atrial intracellular cAMP production in response to forskolin and theophyline (100.0 µmol/L), an inhibitor of phosphodiesterase, potentiated the ouabain-induced increase in cAMP. Ouabain and 8-Bromo-cAMP (0.5 µmol/L) markedly increased atrial ET-1 secretion, which was blocked by H-89 and by PD98059 (30 µmol/L), an inhibitor of extracellular-signal-regulated kinase (ERK) without changing ouabain-induced atrial dynamics. Our results demonstrated that ouabain increases atrial cAMP levels and promotes atrial ET-1 secretion via the mitogen-activated protein kinase (MAPK)/ERK signaling pathway. These findings may explain the development of cardiac hypertrophy in response to digitalis-like compounds. PMID:26807018

  4. Enhanced thromboxane synthesis in atria from infarcted rabbit hearts

    SciTech Connect

    Dunkel, C.G.; Evers, A.S.; Needleman, P.

    1986-03-05

    The authors have previously shown that left ventricular myocardial infarction (MI) results in enhanced thromboxane (Tx) synthesis in response to n-formylmethionyl-leucyl-phenylalanine (fMLP). To anatomically localize this response, cardiac atria and ventricles were removed from normal rabbits and rabbits subjected 4 days previously to MI. Atria were placed in a tissue bath, ventricles were perfused with buffer via the vasculature and both preparations were challenged with fMLP. TxB/sub 2/ in the bath media or ventricular effluent was measured by specific RIA. Atria from normal and infarcted hearts produced similar basal levels of Tx. Following fMLP stimulation, atria from infarcted hearts produced 10X more Tx than normal atria. Ventricles from normal and infarcted hearts produced no Tx basally and only small quantities with fMLP stimulation. Incubation of microsomes prepared from the various chambers of the heart with (/sup 14/-C) arachidonate showed that Tx synthetic capacity in both normal and infarcted hearts resides almost exclusively in the right cardiac atria. These results show that cardiac Tx synthesis is largely an atrial phenomenon and that left ventricular myocardial infarction results in enhanced fMLP-stimulated Tx synthesis.

  5. Sibjotang Increases Atrial Natriuretic Peptide Secretion in Beating Rabbit Atria

    PubMed Central

    Kwon, Oh Jeong; Oh, Hyun Cheol; Lee, Yun Jung; Kim, Hye Yoom; Tan, Rui; Kang, Dae Gill; Lee, Ho Sub

    2015-01-01

    Sibjotang (Shizaotang), traditional herbal medicine formula, which was first documented in the Shanghanlun, has long been prescribed for the treatment of impairment of the body fluid homeostasis. The purpose of the present study was to identify the effects of Sibjotang on the secretion of a cardiac hormone, atrial natriuretic peptide (ANP), one of the main hormones involved in the regulation of the body fluid and blood pressure homeostasis. Water extract of Sibjotang increased ANP secretion concomitantly with an increase in atrial dynamics in a concentration-dependent manner. Sibjotang-induced increase in ANP secretion and positive inotropic effect were attenuated by GO6976 and LY333531, selective inhibitors of conventional protein kinase C, but not Rottlerin, an inhibitor of novel PKCδ. Similarly to the effect of Sibjotang, extracts of components of Sibjotang, Euphorbia kansui, and Daphne genkwa, but not Euphorbia pekinensis and Ziziphus jujuba, increased ANP secretion and atrial dynamics. Ingredients of Sibjotang, apigenin, rosmarinic acid, and salvianolic acid B decreased ANP secretion and atrial dynamics. These findings suggest that Sibjotang increases ANP secretion and atrial dynamics via activation of conventional protein kinase C signaling. This finding provides experimental evidence for the rationale in the use of Sibjotang in the treatment of impairment of the regulation of body fluid and blood pressure homeostasis. PMID:26495007

  6. Extracellular fluid translocation in perfused rabbit atria: implication in control of atrial natriuretic peptide secretion.

    PubMed Central

    Cho, K W; Kim, S H; Hwang, Y H; Seul, K H

    1993-01-01

    1. Transmural transport of 22Na+, 51Cr-EDTA, [3H]inulin and [14C]Dextran (57 kDa) was measured in perfused rabbit atria. The radiolabelled extracellular space (ECS) markers and [14C]Dextran were introduced into the pericardial space or atrial lumen. Atrial volume changes were induced by steps up and down in atrial pressure. 2. Basal rates of transmural transport of radiolabelled ECS markers across the atrial wall were relatively stable up to 70 min. Atrial stretch and release resulted in a rapid but transient, and reversible increase in the ECS fluid (ECF) translocation. The increased translocation of the ECF into the atrial lumen occurred within 15 s of the reduction of atrial distension and returned to the baseline level within 60 s. 3. Transmural transport of [3H]inulin across the atrial wall was bidirectional. 4. The clearance of radiolabelled ECS markers was molecular-size dependent. The transmural clearance of [3H]inulin was dependent on the distension-reduction volume changes induced by atrial stretch and release. Little transport of [14C]Dextran across the atrial wall was observed. 5. The ECF translocation across the atrial wall was not influenced by changes in external Ca2+ but was suppressed by low temperature. 6. Dynamic changes in the ECS of the atrium were observed in response to atrial distension and reduction. The ECS of the atrium increased on distension and decreased on reduction of atrial distension. 7. Reduction in atrial distension resulted in an increase in the secretion of immunoreactive atrial natriuretic peptide (ANP) which coincided with an increase in the translocation of the ECF. The secretion of immunoreactive ANP was a function of the translocation of the ECF. 8. It is suggested that atrial stretch and release may play a role in driving fluid flow within the interstitium and fluid translocation out of the interstitium. This fluid movement presumably leads to convective transport of released ANP into the atrial lumen. PMID:8254526

  7. Effect of the alkaloid (-)cathinone on the release of radioactivity from rabbit atria prelabelled with /sup 3/H-norepinephrine

    SciTech Connect

    Kalix, P.

    1983-02-14

    In certain countries of East Africa and the Arab Peninsula, fresh leaves of the khat shrub are used as a stimulant. The effect of the plant material can be explained by the presence of the phenylalklamine alkaloid (-)cathinone in the leaves, since this substance has been shown to have an amphetamine-like releasing effect on CNS tissue prelabelled with /sup 3/H-dopamine. Characteristically, the chewing of khat is accompanied by sympathomimetic effects, especially at the cardiovascular level. To test whether these might be due to release of neurotransmitter from adrenergic nerve endings, the effect of (-)cathinone on the efflux of radioactivity from isolated rabbit atrium tissue prelabelled with /sup 3/H-norepinephrine was investigated. It was found that, at concentrations below 1 ..mu..M, (-)cathinone caused an immediate increase of efflux. The effect was dose-dependent and was potentiated by pretreatment of the rabbits with reserpine. Preincubation of the tissue with desipramine and cocaine prevented the induction of release by (-)cathinone. The results indicate that the alkaloid (-)cathinone has an amphetamine-like releasing effect on noradrenergic nerve endings and they suggest that the cardiovascular symptoms observed during khat consumption are due to release of neurotransmitter from physiologicl storage sites.

  8. Ion Fluxes through KCa2 (SK) and Cav1 (L-type) Channels Contribute to Chronoselectivity of Adenosine A1 Receptor-Mediated Actions in Spontaneously Beating Rat Atria

    PubMed Central

    Bragança, Bruno; Oliveira-Monteiro, Nádia; Ferreirinha, Fátima; Lima, Pedro A.; Faria, Miguel; Fontes-Sousa, Ana P.; Correia-de-Sá, Paulo

    2016-01-01

    Impulse generation in supraventricular tissue is inhibited by adenosine and acetylcholine via the activation of A1 and M2 receptors coupled to inwardly rectifying GIRK/KIR3.1/3.4 channels, respectively. Unlike M2 receptors, bradycardia produced by A1 receptors activation predominates over negative inotropy. Such difference suggests that other ion currents may contribute to adenosine chronoselectivity. In isolated spontaneously beating rat atria, blockade of KCa2/SK channels with apamin and Cav1 (L-type) channels with nifedipine or verapamil, sensitized atria to the negative inotropic action of the A1 agonist, R-PIA, without affecting the nucleoside negative chronotropy. Patch-clamp experiments in the whole-cell configuration mode demonstrate that adenosine, via A1 receptors, activates the inwardly-rectifying GIRK/KIR3.1/KIR3.4 current resulting in hyperpolarization of atrial cardiomyocytes, which may slow down heart rate. Conversely, the nucleoside inactivates a small conductance Ca2+-activated KCa2/SK outward current, which eventually reduces the repolarizing force and thereby prolong action potentials duration and Ca2+ influx into cardiomyocytes. Immunolocalization studies showed that differences in A1 receptors distribution between the sinoatrial node and surrounding cardiomyocytes do not afford a rationale for adenosine chronoselectivity. Immunolabelling of KIR3.1, KCa2.2, KCa2.3, and Cav1 was also observed throughout the right atrium. Functional data indicate that while both A1 and M2 receptors favor the opening of GIRK/KIR3.1/3.4 channels modulating atrial chronotropy, A1 receptors may additionally restrain KCa2/SK activation thereby compensating atrial inotropic depression by increasing the time available for Ca2+ influx through Cav1 (L-type) channels. PMID:27014060

  9. Ion Fluxes through KCa2 (SK) and Cav1 (L-type) Channels Contribute to Chronoselectivity of Adenosine A1 Receptor-Mediated Actions in Spontaneously Beating Rat Atria.

    PubMed

    Bragança, Bruno; Oliveira-Monteiro, Nádia; Ferreirinha, Fátima; Lima, Pedro A; Faria, Miguel; Fontes-Sousa, Ana P; Correia-de-Sá, Paulo

    2016-01-01

    Impulse generation in supraventricular tissue is inhibited by adenosine and acetylcholine via the activation of A1 and M2 receptors coupled to inwardly rectifying GIRK/KIR3.1/3.4 channels, respectively. Unlike M2 receptors, bradycardia produced by A1 receptors activation predominates over negative inotropy. Such difference suggests that other ion currents may contribute to adenosine chronoselectivity. In isolated spontaneously beating rat atria, blockade of KCa2/SK channels with apamin and Cav1 (L-type) channels with nifedipine or verapamil, sensitized atria to the negative inotropic action of the A1 agonist, R-PIA, without affecting the nucleoside negative chronotropy. Patch-clamp experiments in the whole-cell configuration mode demonstrate that adenosine, via A1 receptors, activates the inwardly-rectifying GIRK/KIR3.1/KIR3.4 current resulting in hyperpolarization of atrial cardiomyocytes, which may slow down heart rate. Conversely, the nucleoside inactivates a small conductance Ca(2+)-activated KCa2/SK outward current, which eventually reduces the repolarizing force and thereby prolong action potentials duration and Ca(2+) influx into cardiomyocytes. Immunolocalization studies showed that differences in A1 receptors distribution between the sinoatrial node and surrounding cardiomyocytes do not afford a rationale for adenosine chronoselectivity. Immunolabelling of KIR3.1, KCa2.2, KCa2.3, and Cav1 was also observed throughout the right atrium. Functional data indicate that while both A1 and M2 receptors favor the opening of GIRK/KIR3.1/3.4 channels modulating atrial chronotropy, A1 receptors may additionally restrain KCa2/SK activation thereby compensating atrial inotropic depression by increasing the time available for Ca(2+) influx through Cav1 (L-type) channels. PMID:27014060

  10. Electrophysiological actions of taurine on spontaneously beating rabbit sino-atrial nodal cells.

    PubMed

    Satoh, H

    1995-01-01

    Effects of taurine on the spontaneous action potentials in rabbit sino-atrial nodal cells were examined at different extracellular Ca2+ concentrations ([Ca]o). Experiments were performed at 36 degrees C. The firing rate of spontaneous activity was 132.5 +/- 12.1 beats/min (n = 18) in normal Tyrode's solution ([Ca]o = 1.8 mM). Increasing [Ca]o level from 0.9 to 10.8 mM significantly changed the maximum rate of depolarization. Other parameters of the action potentials were unaffected. When [Ca]o was 0.9 mM, application of taurine (1 to 20 mM) tended to cause a positive chronotropic effect and hyperpolarized the maximum diastolic potential. In the normal solution (at 1.8 mM [Ca]o), taurine significantly enhanced only the maximum rate of depolarization. In contrast, under high [Ca]o (5.4 and 10.8 mM), taurine at 1 and 5 mM had a negative chronotropic effect, but 20 mM taurine had a positive chronotropic effect. Also, taurine shortened the action potential duration and hyperpolarized the maximum diastolic potential. The maximum rate of depolarization was inhibited. In 10.8 mM [Ca]o solution, irregular spontaneous activity (dysrhythmias) occurred in 4 of 6 preparations, and addition of taurine (1 to 20 mM) abolished it. These results indicate that taurine modulates the action potential configuration in the sino-atrial nodal cells dependent on [Ca]o. PMID:7745842

  11. Effects of angiotensin II on intracellular Ca2+ and pH in isolated beating rabbit hearts and myocytes loaded with the indicator indo-1.

    PubMed Central

    Ikenouchi, H; Barry, W H; Bridge, J H; Weinberg, E O; Apstein, C S; Lorell, B H

    1994-01-01

    1. Angiotensin II increases myocardial contractility in several species, including the rabbit and man. However, it is controversial whether the predominant mechanism is an increase in free cytosolic [Ca2+]i or a change in myofilament Ca2+ sensitivity. To address this question, we infused angiotensin II in isolated perfused rabbit hearts loaded with the Ca2+ indicator indo-1 AM and measured changes in beat-to-beat surface transients of the Ca2+i-sensitive 400:500 nm ratio and left ventricular contractility. The effects of angiotensin II were compared with the response to a Ca(2+)-dependent increase in the inotropic state produced by a change in the perfusate [Ca2+] from 0.9 to 3.6 nM. 2. In the isolated beating heart, an increase in perfusate [Ca2+] caused an increase in left ventricular pressure +dP/dt in association with an increase in peak systolic [Ca2+]i. Angiotensin II perfusion caused a similar increase in left ventricular +dP/dt in the absence of any increase in peak systolic [Ca2+]i. 3. To exclude any contribution of non-myocyte sources of Ca(2+)-sensitive fluorescence which may be present in the intact heart, we also compared the effects of angiotensin II and a change in superfusate [Ca2+] in collagenase-dissociated paced adult rabbit ventricular myocytes loaded with indo-1 AM. In the isolated rabbit myocytes a change in perfusate [Ca2+] from 0.9 to 3.6 mM caused an increase in peak systolic cell shortening coincident with an increase in peak systolic [Ca2+]i. In contrast, angiotensin II caused a similar increase in peak systolic cell shortening whereas there was no increase in peak systolic [Ca2+]i. There was also no change in inward Ca2+ current (ICa) in response to angiotensin II. 4. To investigate further the mechanism of the positive inotropic action of angiotensin II, its effects on intracellular pH were studied in isolated rabbit myocytes loaded with the fluorescent H+ probe SNARF 1. These experiments demonstrated that angiotensin II induced a 0.2 p

  12. Beating irregularity of single pacemaker cells isolated from the rabbit sinoatrial node.

    PubMed Central

    Wilders, R; Jongsma, H J

    1993-01-01

    Single pacemaker heart cells discharge irregularly. Data on fluctuations in interbeat interval of single pacemaker cells isolated from the rabbit sinoatrial node are presented. The coefficient of variation of the interbeat interval is quite small, approximately 2%, even though the coefficient of variation of diastolic depolarization rate is approximately 15%. It has been hypothesized that random fluctuations in interbeat interval arise from the stochastic behavior of the membrane ionic channels. To test this hypothesis, we constructed a single channel model of a single pacemaker cell isolated from the rabbit sinoatrial node, i.e., a model into which the stochastic open-close kinetics of the individual membrane ionic channels are incorporated. Single channel conductances as well as single channel open and closed lifetimes are based on experimental data from whole cell and single channel experiments that have been published in the past decade. Fluctuations in action potential parameters of the model cell are compared with those observed experimentally. It is concluded that fluctuations in interbeat interval of single sinoatrial node pacemaker cells indeed are due to the stochastic open-close kinetics of the membrane ionic channels. PMID:8312495

  13. Diastolic Calcium Release Controls the Beating Rate of Rabbit Sinoatrial Node Cells: Numerical Modeling of the Coupling Process

    PubMed Central

    Maltsev, Victor A.; Vinogradova, Tatiana M.; Bogdanov, Konstantin Y.; Lakatta, Edward G.; Stern, Michael D.

    2004-01-01

    Recent studies employing Ca2+ indicators and confocal microscopy demonstrate substantial local Ca2+ release beneath the cell plasma membrane (subspace) of sinoatrial node cells (SANCs) occurring during diastolic depolarization. Pharmacological and biophysical experiments have suggested that the released Ca2+ interacts with the plasma membrane via the ion current (INaCa) produced by the Na+/Ca2+ exchanger and constitutes an important determinant of the pacemaker rate. This study provides a numerical validation of the functional importance of diastolic Ca2+ release for rate control. The subspace Ca2+ signals in rabbit SANCs were measured by laser confocal microscopy, averaged, and calibrated. The time course of the subspace [Ca2+] displayed both diastolic and systolic components. The diastolic component was mainly due to the local Ca2+ releases; it was numerically approximated and incorporated into a SANC cellular electrophysiology model. The model predicts that the diastolic Ca2+ release strongly interacts with plasma membrane via INaCa and thus controls the phase of the action potential upstroke and ultimately the final action potential rate. PMID:15041695

  14. [Restrictive ventricular septal defect in a dwarf rabbit].

    PubMed

    Hildebrandt, N; Leuser, C; Miltz, D; Henrich, E; Schneider, M

    2016-01-01

    A 9-week-old intact female dwarf rabbit was presented for evaluation of a heart murmur. Physical examination revealed a grade IV/VI systolic heart murmur with the maximal intensity over the right heart base. Evidence for a left-sided cardiomegaly was present on lateral and dorsoventral radiographs. An electrocardiogram was recorded in right lateral recumbency, which revealed a sinus tachycardia with a heart rate of 360 beats/minute. Echocardiography showed normal dimensions for the atria and ventricles. Two-dimensional echocardiography confirmed the presence of a perimembranous ventricular septal defect (VSD) with a diameter of 0.8 mm. Identification of the VSD was possible from a right (long and short axes) and a left parasternal window. Peak flow velocity of the systolic left to right shunt was 5.2 m/s. Additionally, a relative pulmonic stenosis (peak flow in the pulmonary artery of 1.02 m/s, pulsed-wave Doppler) was present. According to these findings, the VSD was classified as restrictive. At this time point, medical treatment was unnecessary. The re-examination after 7 weeks revealed unchanged morphological and haemodynamic findings. The VSD in this dwarf rabbit displayed both in the physical and echocardiographic examinations typical features as seen in dogs and cats as well as in one New Zealand white rabbit. PMID:26763583

  15. Effect of somatostatin on 45Ca fluxes in guinea-pig isolated atria.

    PubMed Central

    Díez, J.; Tamargo, J.

    1987-01-01

    The effect of somatostatin (SS, 10(-6) M and 5 X 10(-6) M) was studied on 45Ca fluxes in guinea-pig isolated atria. SS produced a dose-dependent decrease in 45Ca uptake, this effect being dependent on the stimulation rate and Ca concentration in the bathing media. The decrease in 45Ca uptake was more evident at faster (60 and 180 beats min-1) than at slower frequencies (15 beats min-1) and was less evident in high Ca (5.4 mM). SS had no effect on 45Ca efflux. These results suggest that SS inhibits the slow inward Ca current in guinea-pig atrial fibres. PMID:2435352

  16. The effects of chronic L-name and L-arginine administration on beta-adrenergic responsiveness of STZ-diabetic rat atria.

    PubMed

    Dincer, U D; Ozcelikay, A T; Yilmaz, E D

    2000-05-01

    Recent studies have shown that NO acts as a negative inotrope and chronotrop in cardiac muscle. In the present study, we investigated the effects of the chronic administration of L-NAME and L -arginine on 14-week streptozotocin (STZ)-diabetic rat atria. To study these effects, we compared the alterations of inotropic and chronotropic responses to isoprenaline (ISO) on electrically-driven left atria and spontaneously beating right atria. In addition, we compared the blood pressures of rats in all groups. The chronic administration of L-arginine resulted in a significant reduction in blood pressure of the diabetic rats. On the other hand, the chronic nitric oxide synthase inhibition resulted in a significant increase in blood pressure of diabetic animals. To our findings, maximum positive inotropic responses of ISO diminished in STZ-diabetic, L-arginine and L-NAME treated diabetic groups relative to controls but neither the basal contractility of the left atria nor the pD(2)values were altered significantly in all groups. The basal atrial rate and maximum positive chronotropic responses to ISO were found to be significantly lower in treated and untreated diabetic groups, no significant changes were observed in pD(2)values. Our results demonstrate that the changes in inotropic and chronotropic responses in diabetic rat atria were not influenced by the chronic administration of L-arginine and L-NAME treatments. PMID:10753556

  17. The influence of drugs on the overflow of noradrenaline and the identification of receptors in guinea-pig atria.

    PubMed Central

    Hayes, R.; Howard, J. C.; Nasmyth, P. A.

    1982-01-01

    1 Salbutamol (1.0 microM) and isoprenaline (1.2 nM) significantly increased the fractional release of tritiated noradrenaline from driven left atria but phentolamine (10 microM) failed to do so. Butoxamine (4.0 microM) blocked the increase in overflow produced by isoprenaline. Isoprenaline (1.2 nM), phentolamine (10.0 microM) and salbutamol (1.0 microM) failed to increase the overflow of tritiated noradrenaline from spontaneously beating atria. 2 Spontaneously beating atria were therefore used to identify the receptors mediating chronotropism and inotropism. 3 There was no clear relationship between inotropism and chronotropism. 4 The inotropic effects of both dobutamine (0.04-4.0 microM) and isoprenaline (0.11-9.0 nM) were inhibited by practolol (4.0 microM) and by butoxamine (4.0 microM). The chronotropic effects were inhibited only by practolol (4.0 microM). 5 Both inotropic and chronotropic effects of noradrenaline (3.0-200 nM) were antagonized by practolol (4.0 microM), but not by butoxamine (4.0 microM). Thus both functions appeared to be mediated by beta 1-adrenoceptors when noradrenaline was the agonist. 6 Inotropic responses to salbutamol (0.45-7.5 microM) were inhibited by both practolol (4.0 microM) and by butoxamine (4.0 microM), but chronotropic responses were antagonized only by butoxamine (4.0 microM), Thus salbutamol acts on both beta 1-and beta 2-adrenoceptors to produce an inotropic response but only on beta 2-adrenoceptors to produce its chronotropic response. 7 It is concluded that both beta 1- and beta 2-adrenoceptors can mediate chronotropism and inotropism in guinea-pig isolated atria. Determination of the postsynaptic effects of drugs should be carried out on spontaneously beating rather than driven atria to obviate modification of the responses by noradrenaline release from sympathetic neurons. PMID:7082903

  18. Diminution by benzodiazepines of the chronotropic responses to noradrenaline in rat isolated atria.

    PubMed

    Elgoyhen, B; Adler-Graschinsky, E

    1989-05-30

    The effects of various benzodiazepines on chronotropic responses were assayed in spontaneously beating rat isolated atria. The increases in atrial rate obtained from concentration-response curves to noradrenaline were reduced dose dependently by both the peripheral agonist, Ro 5-4864 5 and 10 microM, and the mixed agonist, diazepam 5, 10 and 50 microM, but not by the central benzodiazepine agonist, clonazepam 10 and 30 microM. The inhibitory effects of the benzodiazepines on the atrial responses to noradrenaline were not counteracted by either the peripheral benzodiazepine antagonist, PK 11195 10 microM, or the central benzodiazepine antagonist, Ro 15-1788 10 and 100 microM. Both 10 microM Ro 5-4864 and 10 microM diazepam also reduced the increases in atrial rate produced by either the phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine, or the adenylate cyclase activator, forskolin. On the contrary, diazepam and Ro 5-4864 did not modify the chronotropic responses of the atria either to direct exposure to CaCl2 or to the calcium agonist, BAY K 8644. The increases in the intracellular levels of cAMP induced by noradrenaline were not modified by Ro 5-4864 and were even increased by 50% in the presence of diazepam. It is concluded that benzodiazepines probably reduce the chronotropic responses to noradrenaline in rat isolated atria through the interaction with the cAMP-linked chain of events that follows the activation of beta-adrenoceptors. PMID:2475348

  19. Analysis of the atypical characteristics of adenosine receptors mediating negative inotropic and chronotropic responses of guinea-pig isolated atria and papillary muscles

    PubMed Central

    Gardner, Neil M; Broadley, Kenneth J

    1999-01-01

    Adenosine receptor(s) mediating negative inotropy of paced left atria, isoprenaline-stimulated paced left atria and papillary muscles, and negative chronotropy of spontaneously beating right atria were characterized.Isometric tension of guinea-pig isolated paced left atria and left ventricular papillary muscles and rate of contraction of spontaneously beating right atria were recorded. Papillary muscles were pre-stimulated with isoprenaline (1×10−8 M). Concentration-response curves (CRCs) for tension or rate reduction by N6-cyclopentyladenosine (CPA), the stereoisomers of N6-(2-phenylisopropyl)adenosine ((+)-PIA and (−)-PIA), 5′-(N-carboxamido)adenosine (NECA), N6-2-(4-aminophenyl)ethyladenosine (APNEA) and N6-(3-iodobenzyl)adenosine-5′-N-methyuromide (IB-MECA) revealed a potency order of CPA=(−)-PIA>NECA in right atria and papillary muscles, which is consistent with involvement of A1-receptors. The potency order in left atria was CPA=NECA>(−)-PIA>(+)-PIA>APNEA, which is not typical of A1 adenosine receptors. Weak activity of APNEA and IB-MECA discounts involvement of A3 receptors.pA2 values for the antagonism of CPA by 8(p-sulfophenyl)theophylline (8-SPT) were calculated from Schild plots (log concentration-ratio against log 8-SPT concentration), the unity slopes of which indicated competitive antagonism. The pA2 value in the papillary muscles was significantly higher than for atrial preparations, indicating a possible difference in receptor characteristics between atrial and papillary muscle responses.In left and right atria there was a limit to the displacement of the CPA CRCs at higher concentrations of 8-SPT. The 8-SPT-resistant component of the response is suggested to arise from duality of coupling of a common A1 receptor through either different G proteins or G protein subunits to independent transduction pathways. The results with papillary muscles can be explained by a typical A1 receptor coupled to a single transduction pathway. PMID

  20. Involvement of Inflammatory Cytokines in Antiarrhythmic Effects of Clofibrate in Ouabain-Induced Arrhythmia in Isolated Rat Atria

    PubMed Central

    Moradi, Somayeh; Nikoui, Vahid; Imran Khan, Muhammad; Amiri, Shayan; Jazaeri, Farahnaz; Bakhtiarian, Azam

    2016-01-01

    Considering the cardioprotective and anti-inflammatory properties of clofibrate, the aim of the present experiment was to investigate the involvement of local and systemic inflammatory cytokines in possible antiarrhythmic effects of clofibrate in ouabain-induced arrhythmia in rats. Rats were orally treated with clofibrate (300 mg/kg), and ouabain (0.56 mg/kg) was administered to animals intraperitoneally. After induction of anesthesia, the atria were isolated and the onset of arrhythmia and asystole was recorded. The levels of inflammatory cytokines in atria were also measured. Clofibrate significantly postponed the onset of arrhythmia and asystole when compared to control group (P ≤ 0.05 and P ≤ 0.01, resp.). While ouabain significantly increased the atrial beating rate in control group (P ≤ 0.05), same treatment did not show similar effect in clofibrate-treated group (P > 0.05). Injection of ouabain significantly increased the atrial and systemic levels of all studied inflammatory cytokines (P ≤ 0.05). Pretreatment with clofibrate could attenuate the ouabain-induced elevation of IL-6 and TNF-α in atria (P ≤ 0.01 and P ≤ 0.05, resp.), as well as ouabain-induced increase in IL-6 in plasma (P ≤ 0.05). Based on our findings, clofibrate may possess antiarrhythmic properties through mitigating the local and systemic inflammatory factors including IL-6 and TNF-α. PMID:26977143

  1. Involvement of Inflammatory Cytokines in Antiarrhythmic Effects of Clofibrate in Ouabain-Induced Arrhythmia in Isolated Rat Atria.

    PubMed

    Moradi, Somayeh; Nikoui, Vahid; Imran Khan, Muhammad; Amiri, Shayan; Jazaeri, Farahnaz; Bakhtiarian, Azam

    2016-01-01

    Considering the cardioprotective and anti-inflammatory properties of clofibrate, the aim of the present experiment was to investigate the involvement of local and systemic inflammatory cytokines in possible antiarrhythmic effects of clofibrate in ouabain-induced arrhythmia in rats. Rats were orally treated with clofibrate (300 mg/kg), and ouabain (0.56 mg/kg) was administered to animals intraperitoneally. After induction of anesthesia, the atria were isolated and the onset of arrhythmia and asystole was recorded. The levels of inflammatory cytokines in atria were also measured. Clofibrate significantly postponed the onset of arrhythmia and asystole when compared to control group (P ≤ 0.05 and P ≤ 0.01, resp.). While ouabain significantly increased the atrial beating rate in control group (P ≤ 0.05), same treatment did not show similar effect in clofibrate-treated group (P > 0.05). Injection of ouabain significantly increased the atrial and systemic levels of all studied inflammatory cytokines (P ≤ 0.05). Pretreatment with clofibrate could attenuate the ouabain-induced elevation of IL-6 and TNF-α in atria (P ≤ 0.01 and P ≤ 0.05, resp.), as well as ouabain-induced increase in IL-6 in plasma (P ≤ 0.05). Based on our findings, clofibrate may possess antiarrhythmic properties through mitigating the local and systemic inflammatory factors including IL-6 and TNF-α. PMID:26977143

  2. Beneficial effect of medicinal plants on the contractility of post-hypoxic isolated guinea pig atria - Potential implications for the treatment of ischemic-reperfusion injury.

    PubMed

    Bipat, Robbert; Toelsie, Jerry R; Magali, Indira; Soekhoe, Rubaina; Stender, Karin; Wangsawirana, Angelique; Oedairadjsingh, Krishan; Pawirodihardjo, Jennifer; Mans, Dennis R A

    2016-08-01

    Context Ischemic-reperfusion injury is accompanied by a decreased contractility of the myocardium. Positive-inotropic agents have proven useful for treating this condition but may exert serious side-effects. Objective In this study, aqueous preparations from Abelmoschus esculentus L. Moench (Malvaceae), Annona muricata L. (Annonaceae), Bixa orellana L. (Bixaceae), Cecropia peltata L. (Moraceae), Erythrina fusca Lour. (Fabaceae), Psidium guajava L. (Myrtaceae) and Terminalia catappa L. (Combretaceae) were evaluated for their ability to improve the decreased contractility of isolated guinea pig atria after hypoxic stress. Materials and methods Guinea pig atria isolated in Ringer-Locke buffer gassed with 100% O2 at 30 °C were exposed for 5 min to hypoxia, then allowed to recover in oxygenated buffer alone or containing a single plant extract (0.001-1 mg/mL). The contractility (g/s) and beating frequency (beats/min), as well as troponin C contents of the bathing solution (ng/mL), were determined and expressed as means ± SDs. Results The extracts of A. muricata, B. orellana, C. peltata and T. catappa caused an increase in the contractility compared to untreated atria of 340 ± 102%, 151 ± 13%, 141 ± 14% and 238 ± 44%, respectively. However, the latter two preparations increased the troponin C contents of the bathing solution to 36 ± 11 and 69 ± 33, compared to the value of 11 ± 3 ng/mL found with untreated atria. Conclusions Preparations from A. muricata and B. orellana may possess positive-inotropic properties which may improve the contractility of the post-hypoxic myocardium. Studies to assess their usefulness in ischemic-reperfusion injury are warranted. PMID:26730936

  3. Beat-to-Beat Blood Pressure Monitor

    NASA Technical Reports Server (NTRS)

    Lee, Yong Jin

    2012-01-01

    This device provides non-invasive beat-to-beat blood pressure measurements and can be worn over the upper arm for prolonged durations. Phase and waveform analyses are performed on filtered proximal and distal photoplethysmographic (PPG) waveforms obtained from the brachial artery. The phase analysis is used primarily for the computation of the mean arterial pressure, while the waveform analysis is used primarily to obtain the pulse pressure. Real-time compliance estimate is used to refine both the mean arterial and pulse pressures to provide the beat-to-beat blood pressure measurement. This wearable physiological monitor can be used to continuously observe the beat-to-beat blood pressure (B3P). It can be used to monitor the effect of prolonged exposures to reduced gravitational environments and the effectiveness of various countermeasures. A number of researchers have used pulse wave velocity (PWV) of blood in the arteries to infer the beat-to-beat blood pressure. There has been documentation of relative success, but a device that is able to provide the required accuracy and repeatability has not yet been developed. It has been demonstrated that an accurate and repeatable blood pressure measurement can be obtained by measuring the phase change (e.g., phase velocity), amplitude change, and distortion of the PPG waveforms along the brachial artery. The approach is based on comparing the full PPG waveform between two points along the artery rather than measuring the time-of-flight. Minimizing the measurement separation and confining the measurement area to a single, well-defined artery allows the waveform to retain the general shape between the two measurement points. This allows signal processing of waveforms to determine the phase and amplitude changes. Photoplethysmography, which measures changes in arterial blood volume, is commonly used to obtain heart rate and blood oxygen saturation. The digitized PPG signals are used as inputs into the beat-to-beat blood

  4. Beat-to-Beat Blood Pressure Monitor

    NASA Technical Reports Server (NTRS)

    Lee, Yong Jin

    2012-01-01

    This device provides non-invasive beat-to-beat blood pressure measurements and can be worn over the upper arm for prolonged durations. Phase and waveform analyses are performed on filtered proximal and distal photoplethysmographic (PPG) waveforms obtained from the brachial artery. The phase analysis is used primarily for the computation of the mean arterial pressure, while the waveform analysis is used primarily to obtain the pulse pressure. Real-time compliance estimate is used to refine both the mean arterial and pulse pressures to provide the beat-to-beat blood pressure measurement. This wearable physiological monitor can be used to continuously observe the beat-to-beat blood pressure (B3P). It can be used to monitor the effect of prolonged exposures to reduced gravitational environments and the effectiveness of various countermeasures. A number of researchers have used pulse wave velocity (PWV) of blood in the arteries to infer the beat-to-beat blood pressure. There has been documentation of relative success, but a device that is able to provide the required accuracy and repeatability has not yet been developed. It has been demonstrated that an accurate and repeatable blood pressure measurement can be obtained by measuring the phase change (e.g., phase velocity), amplitude change, and distortion of the PPG waveforms along the brachial artery. The approach is based on comparing the full PPG waveform between two points along the artery rather than measuring the time-of-flight. Minimizing the measurement separation and confining the measurement area to a single, well-defined artery allows the waveform to retain the general shape between the two measurement points. This allows signal processing of waveforms to determine the phase and amplitude changes.

  5. Model for the respiratory modulation of the heart beat-to-beat time interval series

    NASA Astrophysics Data System (ADS)

    Capurro, Alberto; Diambra, Luis; Malta, C. P.

    2005-09-01

    In this study we present a model for the respiratory modulation of the heart beat-to-beat interval series. The model consists of a set of differential equations used to simulate the membrane potential of a single rabbit sinoatrial node cell, excited with a periodic input signal with added correlated noise. This signal, which simulates the input from the autonomous nervous system to the sinoatrial node, was included in the pacemaker equations as a modulation of the iNaK current pump and the potassium current iK. We focus at modeling the heart beat-to-beat time interval series from normal subjects during meditation of the Kundalini Yoga and Chi techniques. The analysis of the experimental data indicates that while the embedding of pre-meditation and control cases have a roughly circular shape, it acquires a polygonal shape during meditation, triangular for the Kundalini Yoga data and quadrangular in the case of Chi data. The model was used to assess the waveshape of the respiratory signals needed to reproduce the trajectory of the experimental data in the phase space. The embedding of the Chi data could be reproduced using a periodic signal obtained by smoothing a square wave. In the case of Kundalini Yoga data, the embedding was reproduced with a periodic signal obtained by smoothing a triangular wave having a rising branch of longer duration than the decreasing branch. Our study provides an estimation of the respiratory signal using only the heart beat-to-beat time interval series.

  6. A mechanical characterization of the porcine atria at the healthy stage and after ventricular tachypacing.

    PubMed

    Bellini, Chiara; Di Martino, Elena S

    2012-02-01

    Atrial fibrillation (AF) is a cardiac arrhythmia that highly increases the risk of stroke and is associated with significant but still unexplored changes in the mechanical behavior of the tissue. Planar biaxial tests were performed on tissue specimens from pigs at the healthy stage and after ventricular tachypacing (VTP), a procedure applied to reproduce the relevant features of AF. The local arrangement of the fiber bundles in the tissue was investigated on specimens from rabbit atria by means of circularly polarized light. Based on this, mechanical data were fitted to two anisotropic constitutive relationships, including a four-parameter Fung-type model and a microstructurally-motivated model. Accounting for the fiber-induced anisotropy brought average R(2) = 0.807 for the microstructurally-motivated model and average R(2) = 0.949 for the Fung model. Validation of the fitted constitutive relationships was performed by means of FEM simulations coupled to FORTRAN routines. The performances of the two material models in predicting the second Piola-Kirchhoff stress were comparable, with average errors <3.1%. However, the Fung model outperformed the other in the prediction of the Green-Lagrange strain, with 9.2% maximum average error. To increase model generality, a proper averaging procedure accounting for nonlinearities was used to obtain average material parameters. In general, a stiffer behavior after VTP was noted. PMID:22482675

  7. Gene Expression and Genetic Variation in Human Atria

    PubMed Central

    Lin, Honghuang; Dolmatova, Elena V.; Morley, Michael P.; Lunetta, Kathryn L.; McManus, David D.; Magnani, Jared W.; Margulies, Kenneth B.; Hakonarson, Hakon; del Monte, Federica; Benjamin, Emelia J.; Cappola, Thomas P.; Ellinor, Patrick T.

    2013-01-01

    Background The human left and right atria have different susceptibilities to develop atrial fibrillation (AF). However, the molecular events related to structural and functional changes that enhance AF susceptibility are still poorly understood. Objective To characterize gene expression and genetic variation in human atria. Methods We studied the gene expression profiles and genetic variations in 53 left atrial and 52 right atrial tissue samples collected from the Myocardial Applied Genomics Network (MAGNet) repository. The tissues were collected from heart failure patients undergoing transplantation and from unused organ donor hearts with normal ventricular function. Gene expression was profiled using the Affymetrix GeneChip Human Genome U133A Array. Genetic variation was profiled using the Affymetrix Genome-Wide Human SNP Array 6.0. Results We found that 109 genes were differentially expressed between left and right atrial tissues. A total of 187 and 259 significant cis-associations between transcript levels and genetic variants were identified in left and right atrial tissues, respectively. We also found that a SNP at a known AF locus, rs3740293, was associated with the expression of MYOZ1 in both left and right atrial tissues. Conclusion We found a distinct transcriptional profile between the right and left atrium, and extensive cis-associations between atrial transcripts and common genetic variants. Our results implicate MYOZ1 as the causative gene at the chromosome 10q22 locus for AF. PMID:24177373

  8. Heterogeneous three-dimensional anatomical and electrophysiological model of human atria.

    PubMed

    Seemann, Gunnar; Höper, Christine; Sachse, Frank B; Dössel, Olaf; Holden, Arun V; Zhang, Henggui

    2006-06-15

    Investigating the mechanisms underlying the genesis and conduction of electrical excitation in the atria at physiological and pathological states is of great importance. To provide knowledge concerning the mechanisms of excitation, we constructed a biophysical detailed and anatomically accurate computer model of human atria that incorporates both structural and electrophysiological heterogeneities. The three-dimensional geometry was extracted from the visible female dataset. The sinoatrial node (SAN) and atrium, including crista terminalis (CT), pectinate muscles (PM), appendages (APG) and Bachmann's bundle (BB) were segmented in this work. Fibre orientation in CT, PM and BB was set to local longitudinal direction. Descriptions for all used cell types were based on modifications of the Courtemanche et al. model of a human atrial cell. Maximum conductances of Ito, IKr and ICa,L were modified for PM, CT, APG and atrioventricular ring to reproduce measured action potentials (AP). Pacemaker activity in the human SAN was reproduced by removing IK1, but including If, ICa,T, and gradients of channel conductances as described in previous studies for heterogeneous rabbit SAN. Anisotropic conduction was computed with a monodomain model using the finite element method. The transversal to longitudinal ratio of conductivity for PM, CT and BB was 1:9. Atrial working myocardium (AWM) was set to be isotropic. Simulation of atrial electrophysiology showed initiation of APs in the SAN centre. The excitation spread afterwards to the periphery near to the region of the CT and preferentially towards the atrioventricular region. The excitation extends over the right atrium along PM. Both CT and PM activated the right AWM. Earliest activation of the left atrium was through BB and excitation spread over to the APG. The conduction velocities were 0.6ms-1 for AWM, 1.2ms-1 for CT, 1.6ms-1 for PM and 1.1ms-1 for BB at a rate of 63bpm. The simulations revealed that bundles form dominant

  9. Binaural beat salience

    PubMed Central

    Grose, John H.; Buss, Emily; Hall, Joseph W.

    2012-01-01

    Previous studies of binaural beats have noted individual variability and response lability, but little attention has been paid to the salience of the binaural beat percept. The purpose of this study was to gauge the strength of the binaural beat percept by matching its salience to that of sinusoidal amplitude modulation (SAM), and to then compare rate discrimination for the two types of fluctuation. Rate discrimination was measured for standard rates of 4, 8, 16, and 32 Hz – all in the 500-Hz carrier region. Twelve normal-hearing adults participated in this study. The results indicated that discrimination acuity for binaural beats is similar to that for SAM tones whose depths of modulation have been adjusted to provide equivalent modulation salience. The matched-salience SAM tones had relatively shallow depths of modulation, suggesting that the perceptual strength of binaural beats is relatively weak, although all listeners perceived them. The Weber fraction for detection of an increase in binaural beat rate is roughly constant across beat rates, at least for rates above 4 Hz, as is rate discrimination for SAM tones. PMID:22326292

  10. Nonlinear Beat Cepheid Models

    NASA Astrophysics Data System (ADS)

    Kolláth, Z.; Beaulieu, J. P.; Buchler, J. R.; Yecko, P.

    1998-07-01

    The numerical hydrodynamic modeling of beat Cepheid behavior has been a long-standing quest in which purely radiative models have failed miserably. We find that beat pulsations occur naturally when turbulent convection is accounted for in our hydrodynamics codes. The development of a relaxation code and of a Floquet stability analysis greatly facilitates the search for and analysis of beat Cepheid models. The conditions for the occurrence of beat behavior can be understood easily and at a fundamental level with the help of amplitude equations. Here a discriminant \\Dscr arises whose sign decides whether single-mode or double-mode pulsations can occur in a model, and this \\Dscr depends only on the values of the nonlinear coupling coefficients between the fundamental and the first overtone modes. For radiative models \\Dscr is always found to be negative, but with sufficiently strong turbulent convection its sign reverses.

  11. Prevention of adenosine A2A receptor activation diminishes beat-to-beat alternation in human atrial myocytes.

    PubMed

    Molina, Cristina E; Llach, Anna; Herraiz-Martínez, Adela; Tarifa, Carmen; Barriga, Montserrat; Wiegerinck, Rob F; Fernandes, Jacqueline; Cabello, Nuria; Vallmitjana, Alex; Benitéz, Raúl; Montiel, José; Cinca, Juan; Hove-Madsen, Leif

    2016-01-01

    Atrial fibrillation (AF) has been associated with increased spontaneous calcium release from the sarcoplasmic reticulum and linked to increased adenosine A2A receptor (A2AR) expression and activation. Here we tested whether this may favor atrial arrhythmogenesis by promoting beat-to-beat alternation and irregularity. Patch-clamp and confocal calcium imaging was used to measure the beat-to-beat response of the calcium current and transient in human atrial myocytes. Responses were classified as uniform, alternating or irregular and stimulation of Gs-protein coupled receptors decreased the frequency where a uniform response could be maintained from 1.0 ± 0.1 to 0.6 ± 0.1 Hz; p < 0.01 for beta-adrenergic receptors and from 1.4 ± 0.1 to 0.5 ± 0.1 Hz; p < 0.05 for A2ARs. The latter was linked to increased spontaneous calcium release and after-depolarizations. Moreover, A2AR activation increased the fraction of non-uniformly responding cells in HL-1 myocyte cultures from 19 ± 3 to 51 ± 9 %; p < 0.02, and electrical mapping in perfused porcine atria revealed that adenosine induced electrical alternans at longer cycle lengths, doubled the fraction of electrodes showing alternation, and increased the amplitude of alternations. Importantly, protein kinase A inhibition increased the highest frequency where uniform responses could be maintained from 0.84 ± 0.12 to 1.86 ± 0.11 Hz; p < 0.001 and prevention of A2AR-activation with exogenous adenosine deaminase selectively increased the threshold from 0.8 ± 0.1 to 1.2 ± 0.1 Hz; p = 0.001 in myocytes from patients with AF. In conclusion, A2AR-activation promotes beat-to-beat irregularities in the calcium transient in human atrial myocytes, and prevention of A2AR activation may be a novel means to maintain uniform beat-to-beat responses at higher beating frequencies in patients with atrial fibrillation. PMID:26611209

  12. Thermally-induced ventilation applications in atria: a state-of-the-art report

    SciTech Connect

    Not Available

    1981-06-01

    Atria dating back as far as the Roman Empire from fourteen countries were reviewed. Several tentative conclusions have emerged regarding optimal atria aspect ratios and mechanisms to control the atria microclimate. Three areas were considered in the review of atrium technical considerations: cooling design concepts, thermal functions and atrium operating principles. The cooling design concepts discussed include radiative cooling, shading, convective cooling (wind-driven and thermally-induced), and thermal mass. Assumed atrium thermal functions consist of the control of incoming solar radiation, ventilation, cooling and day-lighting. Primary atrium operating mechanisms are convective, conductive and radiative heat transfer. The partitioning of these energy flows are highly dependent upon specific atrium system parameters. Existing natural convection heat transfer and ventilation algorithms as they pertain to atria are presented. The limitations and major assumptions used in developing these algorithms are discussed. The computer programs reviewed include: (1) BLAST, (2) CALPAS3, (3) DEROB, (4) DOE-2A, (5) FREHEAT, (6) PASOLE, (7) PEGFIX, (8) NBSLD, (9) TWOZONE, and (10) UWENSOL. Out of the many atria surveyed, forty-one from thirty-seven locations in the US have been identified and documented. Most of the sites identified are commercial buildings. Sites are categorized into those already constructed and those still in the planning or building stages. Annotated bibliographies for information about atria are presented. These are grouped into the following subject areas: (1) general passive cooling, (2) climate and human comfort, (3) thermal and ventilation equations, (4) atria, (5) courtyards, and (6) measurement techniques.

  13. Metal MEMS Tools for Beating-heart Tissue Approximation

    PubMed Central

    Butler, Evan J.; Folk, Chris; Cohen, Adam; Vasilyev, Nikolay V.; Chen, Rich; del Nido, Pedro J.; Dupont, Pierre E.

    2011-01-01

    Achieving superior outcomes through the use of robots in medical applications requires an integrated approach to the design of the robot, tooling and the procedure itself. In this paper, this approach is applied to develop a robotic technique for closing abnormal communication between the atria of the heart. The goal is to achieve the efficacy of surgical closure as performed on a stopped, open heart with the reduced risk and trauma of a beating-heart catheter-based procedure. In the proposed approach, a concentric tube robot is used to percutaneously access the right atrium and deploy a tissue approximation device. The device is constructed using a metal MEMS fabrication process and is designed to both fit the manipulation capabilities of the robot as well as to reproduce the beneficial features of surgical closure by suture. Experimental results demonstrate device efficacy through manual in-vivo deployment and bench-top robotic deployment. PMID:22229109

  14. Cellular potentials, electrogenic sodium pumping and sensitivity in guinea-pig atria.

    PubMed

    Schulz, J C; Fleming, W W; Westfall, D P; Millecchia, R

    1984-10-01

    Intracellular recording techniques in guinea-pig atrial pacemaker and nonpacemaker cells were used to investigate 1) the role of membrane potential changes in postjunctional supersensitivity, 2) the electrogenicity of the Na+,K+ pump and 3) the role of electrogenic pumping in sensitivity of the atria to agonists. In nonpacemaker cells, ouabain (10(-6) M) had no effect on resting membrane potential (left atria) or maximum diastolic potential (right atria). However, ouabain effectively suppressed the transient hyperpolarization that followed cessation of electrical stimulation. In pacemaker cells, ouabain and chronic treatment with reserpine (0.1 mg/kg/day) produced quite different patterns of changes in intracellular potentials. Chronic treatment with reserpine induced chronotropic supersensitivity to isoproterenol but not to histamine. Ouabain did not alter the chronotropic sensitivity to either agonist. The effects of isoproterenol and histamine on intracellular potentials in pacemaker cells were investigated in the presence and absence of ouabain and in control atria vs. atria from guinea pigs chronically pretreated with reserpine. Analysis of the data indicated that 1) electrophysiological measurements do not provide a discernible explanation for chronotropic supersensitivity, 2) the Na+ pump has the capacity for electrogenic pumping under conditions of Na+ loading, but demonstrates little indication of electrogenicity under basal conditions and 3) chronic treatment with reserpine does suppress the Na+,K+ pump in some areas of the right atrium, but this activity probably does not contribute to chronotropic supersensitivity. Other possible mechanisms of postjunctional supersensitivity in atria are discussed. PMID:6491974

  15. Purification of the muscarinic acetylcholine receptor from porcine atria.

    PubMed Central

    Peterson, G L; Herron, G S; Yamaki, M; Fullerton, D S; Schimerlik, M I

    1984-01-01

    The muscarinic acetylcholine receptor from porcine atria has been purified 100,000-fold to homogeneity by solubilization in digitonin/cholate and sequential chromatography on wheat germ agglutinin-agarose, diethylaminoethylagarose, hydroxylapatite, and 3-(2'-aminobenzhydryloxy)tropane-agarose. The yield of purified receptor was 4.3% of that found in the membrane fraction, and the purified receptor bound 11.1-12.8 nmol of L-[3H]quinuclidinyl benzilate per mg of protein, corresponding to a binding component Mr of 78,400-90,000. The purified receptor preparation consisted of two polypeptides in approximately equimolar amounts when examined on silver-stained sodium dodecyl sulfate/polyacrylamide gels. The larger polypeptide (Mr 78,000 on 8% polyacrylamide gels) was specifically alkylated with [3H]propylbenzilylcholine mustard, whereas the smaller polypeptide (Mr 14,800) was not labeled. The possibility that the small polypeptide is a contaminant fortuitously appearing in equimolar amounts with the large polypeptide cannot be ruled out at this time. The purified preparation was highly stable, with no measurable change in the number of ligand binding sites or the gel pattern after 1 month's storage on ice. Scatchard analysis showed a single class of binding sites for the antagonist L-[3H]quinuclidinyl benzilate with a dissociation constant of 61 +/- 4 pM. Equilibrium titration experiments demonstrated that the antagonist L-hyoscyamine displaced L-[3H]quinuclidinyl benzilate from a single class of sites (Kd = 475 +/- 30 pM), whereas the agonist carbamoylcholine interacted at two populations of sites (53% +/- 3% high affinity, Kd = 1.1 +/- 0.3 microM; 47% +/- 3% low affinity, Kd = 67 +/- 14 microM). The ligand binding data were very similar to that for the membrane-bound receptor, suggesting that the receptor has not been altered radically during purification. Images PMID:6589642

  16. Optimal ciliary beating patterns

    NASA Astrophysics Data System (ADS)

    Vilfan, Andrej; Osterman, Natan

    2011-11-01

    We introduce a measure for energetic efficiency of single or collective biological cilia. We define the efficiency of a single cilium as Q2 / P , where Q is the volume flow rate of the pumped fluid and P is the dissipated power. For ciliary arrays, we define it as (ρQ) 2 / (ρP) , with ρ denoting the surface density of cilia. We then numerically determine the optimal beating patterns according to this criterion. For a single cilium optimization leads to curly, somewhat counterintuitive patterns. But when looking at a densely ciliated surface, the optimal patterns become remarkably similar to what is observed in microorganisms like Paramecium. The optimal beating pattern then consists of a fast effective stroke and a slow sweeping recovery stroke. Metachronal waves lead to a significantly higher efficiency than synchronous beating. Efficiency also increases with an increasing density of cilia up to the point where crowding becomes a problem. We finally relate the pumping efficiency of cilia to the swimming efficiency of a spherical microorganism and show that the experimentally estimated efficiency of Paramecium is surprisingly close to the theoretically possible optimum.

  17. Species differences in the negative inotropic effect of acetylcholine and soman in rat, guinea pig, and rabbit hearts. (Reannouncement with new availability information)

    SciTech Connect

    Maxwell, D.M.; Thomsen, R.H.; Baskin, S.I.

    1991-12-31

    Acetylcholine reduced atrial contractions by 82.5% in guinea pig, 50.8% in rat, and 41.5% in rabbit. 2. The EC50, values for the negative inotropic effect of acetylcholine were 3.3 x 10(-7) M in rat and guinea pig atria and 4.1 x 10(-6) M in rabbit atria. 3. There was no correlation between the species differences in the negative inotropic effect of acetylcholine in atria and the density or affinity of acetylcholinesterase or muscarinic receptors. 4. Inhibition of atrial acetylcholinesterase with soman reduced the EC50 of acetylcholine three-fold in all species, but did not change the maximal inotropic effect of acetylcholine. 5. Species differences in the negative inotropic effect of acetylcholine may be caused by differences in the coupling between myocardial muscarinic receptors and the ion channels that mediate negative inotropy. Acetylcholine, cardiovascular response, species variation negative inotropic response.

  18. A beat frequency buncher

    SciTech Connect

    Storm, D.W.; Corcoran, D.T.; Harper, G.C.

    1995-09-01

    A superconducting high energy buncher operating at 13/12 times the linac frequency has been built and installed, to combine with the low energy buncher operating at 1/12 the linac frequency. The system is synchronized so the linac and high energy buncher beat frequency remains in phase with the low energy buncher. On linac cycles not corresponding to a primary bunch, the high energy buncher bunches residual beam away from the linac longitudinal acceptance rather than into it. The resonator for the new high energy buncher was constructed by shortening an existing low-{beta} resonator.

  19. Disposal rabbit

    DOEpatents

    Lewis, L.C.; Trammell, D.R.

    1983-10-12

    A disposable rabbit for transferring radioactive samples in a pneumatic transfer system comprises aerated plastic shaped in such a manner as to hold a radioactive sample and aerated such that dissolution of the rabbit in a solvent followed by evaporation of the solid yields solid waste material having a volume significantly smaller than the original volume of the rabbit.

  20. Disposable rabbit

    DOEpatents

    Lewis, Leroy C.; Trammell, David R.

    1986-01-01

    A disposable rabbit for transferring radioactive samples in a pneumatic transfer system comprises aerated plastic shaped in such a manner as to hold a radioactive sample and aerated such that dissolution of the rabbit in a solvent followed by evaporation of the solid yields solid waste material having a volume significantly smaller than the original volume of the rabbit.

  1. Down-regulation of the small conductance calcium-activated potassium channels in diabetic mouse atria.

    PubMed

    Yi, Fu; Ling, Tian-You; Lu, Tong; Wang, Xiao-Li; Li, Jingchao; Claycomb, William C; Shen, Win-Kuang; Lee, Hon-Chi

    2015-03-13

    The small conductance Ca(2+)-activated K(+) (SK) channels have recently been found to be expressed in the heart, and genome-wide association studies have shown that they are implicated in atrial fibrillation. Diabetes mellitus is an independent risk factor of atrial fibrillation, but the ionic mechanism underlying this relationship remains unclear. We hypothesized that SK channel function is abnormal in diabetes mellitus, leading to altered cardiac electrophysiology. We found that in streptozotocin-induced diabetic mice, the expression of SK2 and SK3 isoforms was down-regulated by 85 and 92%, respectively, whereas that of SK1 was not changed. SK currents from isolated diabetic mouse atrial myocytes were significantly reduced compared with controls. The resting potentials of isolated atrial preparations were similar between control and diabetic mice, but action potential durations were significantly prolonged in the diabetic atria. Exposure to apamin significantly prolonged action potential durations in control but not in diabetic atria. Production of reactive oxygen species was significantly increased in diabetic atria and in high glucose-cultured HL-1 cells, whereas exposure of HL-1 cells in normal glucose culture to H2O2 reduced the expression of SK2 and SK3. Tyrosine nitration in SK2 and SK3 was significantly increased by high glucose culture, leading to accelerated channel turnover. Treatment with Tiron prevented these changes. Our results suggest that increased oxidative stress in diabetes results in SK channel-associated electrical remodeling in diabetic atria and may promote arrhythmogenesis. PMID:25605734

  2. 3D virtual human atria: A computational platform for studying clinical atrial fibrillation.

    PubMed

    Aslanidi, Oleg V; Colman, Michael A; Stott, Jonathan; Dobrzynski, Halina; Boyett, Mark R; Holden, Arun V; Zhang, Henggui

    2011-10-01

    Despite a vast amount of experimental and clinical data on the underlying ionic, cellular and tissue substrates, the mechanisms of common atrial arrhythmias (such as atrial fibrillation, AF) arising from the functional interactions at the whole atria level remain unclear. Computational modelling provides a quantitative framework for integrating such multi-scale data and understanding the arrhythmogenic behaviour that emerges from the collective spatio-temporal dynamics in all parts of the heart. In this study, we have developed a multi-scale hierarchy of biophysically detailed computational models for the human atria--the 3D virtual human atria. Primarily, diffusion tensor MRI reconstruction of the tissue geometry and fibre orientation in the human sinoatrial node (SAN) and surrounding atrial muscle was integrated into the 3D model of the whole atria dissected from the Visible Human dataset. The anatomical models were combined with the heterogeneous atrial action potential (AP) models, and used to simulate the AP conduction in the human atria under various conditions: SAN pacemaking and atrial activation in the normal rhythm, break-down of regular AP wave-fronts during rapid atrial pacing, and the genesis of multiple re-entrant wavelets characteristic of AF. Contributions of different properties of the tissue to mechanisms of the normal rhythm and arrhythmogenesis were investigated. Primarily, the simulations showed that tissue heterogeneity caused the break-down of the normal AP wave-fronts at rapid pacing rates, which initiated a pair of re-entrant spiral waves; and tissue anisotropy resulted in a further break-down of the spiral waves into multiple meandering wavelets characteristic of AF. The 3D virtual atria model itself was incorporated into the torso model to simulate the body surface ECG patterns in the normal and arrhythmic conditions. Therefore, a state-of-the-art computational platform has been developed, which can be used for studying multi

  3. Beat to beat variability in cardiovascular variables: noise or music?

    NASA Technical Reports Server (NTRS)

    Appel, M. L.; Berger, R. D.; Saul, J. P.; Smith, J. M.; Cohen, R. J.

    1989-01-01

    Cardiovascular variables such as heart rate, arterial blood pressure, stroke volume and the shape of electrocardiographic complexes all fluctuate on a beat to beat basis. These fluctuations have traditionally been ignored or, at best, treated as noise to be averaged out. The variability in cardiovascular signals reflects the homeodynamic interplay between perturbations to cardiovascular function and the dynamic response of the cardiovascular regulatory systems. Modern signal processing techniques provide a means of analyzing beat to beat fluctuations in cardiovascular signals, so as to permit a quantitative, noninvasive or minimally invasive method of assessing closed loop hemodynamic regulation and cardiac electrical stability. This method promises to provide a new approach to the clinical diagnosis and management of alterations in cardiovascular regulation and stability.

  4. Detection of heart beats in multimodal data: a robust beat-to-beat interval estimation approach.

    PubMed

    Antink, Christoph Hoog; Brüser, Christoph; Leonhardt, Steffen

    2015-08-01

    The heart rate and its variability play a vital role in the continuous monitoring of patients, especially in the critical care unit. They are commonly derived automatically from the electrocardiogram as the interval between consecutive heart beat. While their identification by QRS-complexes is straightforward under ideal conditions, the exact localization can be a challenging task if the signal is severely contaminated with noise and artifacts. At the same time, other signals directly related to cardiac activity are often available. In this multi-sensor scenario, methods of multimodal sensor-fusion allow the exploitation of redundancies to increase the accuracy and robustness of beat detection.In this paper, an algorithm for the robust detection of heart beats in multimodal data is presented. Classic peak-detection is augmented by robust multi-channel, multimodal interval estimation to eliminate false detections and insert missing beats. This approach yielded a score of 90.70 and was thus ranked third place in the PhysioNet/Computing in Cardiology Challenge 2014: Robust Detection of Heart Beats in Muthmodal Data follow-up analysis.In the future, the robust beat-to-beat interval estimator may directly be used for the automated processing of multimodal patient data for applications such as diagnosis support and intelligent alarming. PMID:26218172

  5. Diabetes Alters the Expression and Translocation of the Insulin-Sensitive Glucose Transporters 4 and 8 in the Atria

    PubMed Central

    Maria, Zahra; Campolo, Allison R.; Lacombe, Veronique A.

    2015-01-01

    Although diabetes has been identified as a major risk factor for atrial fibrillation, little is known about glucose metabolism in the healthy and diabetic atria. Glucose transport into the cell, the rate-limiting step of glucose utilization, is regulated by the Glucose Transporters (GLUTs). Although GLUT4 is the major isoform in the heart, GLUT8 has recently emerged as a novel cardiac isoform. We hypothesized that GLUT-4 and -8 translocation to the atrial cell surface will be regulated by insulin and impaired during insulin-dependent diabetes. GLUT protein content was measured by Western blotting in healthy cardiac myocytes and type 1 (streptozotocin-induced, T1Dx) diabetic rodents. Active cell surface GLUT content was measured using a biotinylated photolabeled assay in the perfused heart. In the healthy atria, insulin stimulation increased both GLUT-4 and -8 translocation to the cell surface (by 100% and 240%, respectively, P<0.05). Upon insulin stimulation, we reported an increase in Akt (Th308 and s473 sites) and AS160 phosphorylation, which was positively (P<0.05) correlated with GLUT4 protein content in the healthy atria. During diabetes, active cell surface GLUT-4 and -8 content was downregulated in the atria (by 70% and 90%, respectively, P<0.05). Akt and AS160 phosphorylation was not impaired in the diabetic atria, suggesting the presence of an intact insulin signaling pathway. This was confirmed by the rescued translocation of GLUT-4 and -8 to the atrial cell surface upon insulin stimulation in the atria of type 1 diabetic subjects. In conclusion, our data suggest that: 1) both GLUT-4 and -8 are insulin-sensitive in the healthy atria through an Akt/AS160 dependent pathway; 2) GLUT-4 and -8 trafficking is impaired in the diabetic atria and rescued by insulin treatment. Alterations in atrial glucose transport may induce perturbations in energy production, which may provide a metabolic substrate for atrial fibrillation during diabetes. PMID:26720696

  6. Effects of endothelin-1 chronic stimulation on electrical restitution, beat-to-beat variability of repolarization, and ventricular arrhythmogenesis.

    PubMed

    Liu, Tao; Qin, Mu; Shi, Shao Bo; Chen, Zhen; Wang, Teng; Huang, Cong-Xin

    2013-12-01

    Chronically elevated levels of endothelin-1 (ET-1) have been detected in several cardiovascular diseases. In this study, we investigated the chronic effects of ET-1 on the electrophysiological characteristics expected to influence the genesis and maintenance of ventricular arrhythmia (VA). Rabbits were randomized to ET-1 (ET-1 group) or 0.9% saline (control group) for 2 weeks. The S1-S2 protocol and S1-S1 dynamic pacing were performed to assess the action potential duration restitution (APDR) and to induce APD alternans or VA in 4 sites of Langendorff-perfused rabbit hearts. The beat-to-beat variability of repolarization was quantified as short-term variability and long-term variability. Compared with the control group, chronic ET-1 administration significantly prolonged QT intervals, APD at 90% repolarization (APD₉₀), and effective refractory period (ERP), steepened the maximum slopes of the APDR curve, decreased the ERP/APD₉₀ ratio, and increased the spatial dispersions of APD₉₀, ERP, and maximum slopes (P < 0.05 for all). Moreover, chronic ET-1 administration markedly increased the short-term variability and long-term variability (P < 0.01 for all). APD alternans occurred in both groups, but the threshold of APD alternans was decreased at all sites in the ET-1 group (P < 0.01 for all). We also observed that chronic ET-1 stimulation significantly increased the incidence and duration of the VA episodes. These results suggest that chronic stimulation with ET-1 facilitated VA by steepening the APDR curve and increasing the spatial dispersion of APDR and beat-to-beat variability of repolarization. PMID:24084217

  7. Variable t-tubule organization and Ca2+ homeostasis across the atria.

    PubMed

    Frisk, Michael; Koivumäki, Jussi T; Norseng, Per A; Maleckar, Mary M; Sejersted, Ole M; Louch, William E

    2014-08-15

    Although t-tubules have traditionally been thought to be absent in atrial cardiomyocytes, recent studies have suggested that t-tubules exist in the atria of large mammals. However, it is unclear whether regional differences in t-tubule organization exist that define cardiomyocyte function across the atria. We sought to investigate regional t-tubule density in pig and rat atria and the consequences for cardiomyocyte Ca(2+) homeostasis. We observed t-tubules in approximately one-third of rat atrial cardiomyocytes, in both tissue cryosections and isolated cardiomyocytes. In a minority (≈10%) of atrial cardiomyocytes, the t-tubular network was well organized, with a transverse structure resembling that of ventricular cardiomyocytes. In both rat and pig atrial tissue, we observed higher t-tubule density in the epicardium than in the endocardium. Consistent with high variability in the distribution of t-tubules and Ca(2+) channels among cells, L-type Ca(2+) current amplitude was also highly variable and steeply dependent on capacitance and t-tubule density. Accordingly, Ca(2+) transients showed great variability in Ca(2+) release synchrony. Simultaneous imaging of the cell membrane and Ca(2+) transients confirmed t-tubule functionality. Results from mathematical modeling indicated that a transmural gradient in t-tubule organization and Ca(2+) release kinetics supports synchronization of contraction across the atrial wall and may underlie transmural differences in the refractory period. In conclusion, our results indicate that t-tubule density is highly variable across the atria. We propose that higher t-tubule density in cells localized in the epicardium may promote synchronization of contraction across the atrial wall. PMID:24951751

  8. Simulation of Ectopic Pacemakers in the Heart: Multiple Ectopic Beats Generated by Reentry inside Fibrotic Regions

    PubMed Central

    Gouvêa de Barros, Bruno; Weber dos Santos, Rodrigo; Lobosco, Marcelo; Alonso, Sergio

    2015-01-01

    The inclusion of nonconducting media, mimicking cardiac fibrosis, in two models of cardiac tissue produces the formation of ectopic beats. The fraction of nonconducting media in comparison with the fraction of healthy myocytes and the topological distribution of cells determines the probability of ectopic beat generation. First, a detailed subcellular microscopic model that accounts for the microstructure of the cardiac tissue is constructed and employed for the numerical simulation of action potential propagation. Next, an equivalent discrete model is implemented, which permits a faster integration of the equations. This discrete model is a simplified version of the microscopic model that maintains the distribution of connections between cells. Both models produce similar results when describing action potential propagation in homogeneous tissue; however, they slightly differ in the generation of ectopic beats in heterogeneous tissue. Nevertheless, both models present the generation of reentry inside fibrotic tissues. This kind of reentry restricted to microfibrosis regions can result in the formation of ectopic pacemakers, that is, regions that will generate a series of ectopic stimulus at a fast pacing rate. In turn, such activity has been related to trigger fibrillation in the atria and in the ventricles in clinical and animal studies. PMID:26583127

  9. Project HeartBeat!

    PubMed Central

    Labarthe, Darwin R.; Dai, Shifan; Day, R. Sue; Fulton, Janet E.; Grunbaum, Jo Anne; Shah, Syed M.; Wen, Eugene

    2015-01-01

    Major cardiovascular disease (CVD) risk factors begin development in childhood and adolescence. Project HeartBeat! studied early development of these risk factors as growth processes. Growth, body composition, sexual maturation, major CVD risk factors, and cardiac structure and function were monitored every 4 months for up to 4 years among 678 children and adolescents (49.1% girls; 20.1% blacks) aged 8, 11, or 14 years at study entry. All resided in The Woodlands or Conroe TX. Interviews were conducted at entry and annually on diet, physical activity, and health history of participants and their families. Data were collected from 1991 to 1995, and study investigators continue data analysis and reporting. Overlap in ages at examination among three cohorts (aged 8–12, 11–15, and 14–18 years at baseline) and use of multilevel modeling methods permit analysis of some 5500 observations on each principal variable for the synthetic cohort from ages 8 to 18 years. The mixed-longitudinal design provides trajectories of change with age, for total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides; systolic, and fourth-phase and fifth-phase diastolic blood pressure, and left ventricular mass. These trajectories are then related to concurrent measures of multiple indices of body composition and sexual maturation and adjusted for energy intake and physical activity. The data provide valuable insights into risk factor development and suggest a fresh approach to understanding influences on blood lipids, blood pressure, and left ventricular mass during the period of childhood and adolescence, a period of dynamic change in these risk factors. PMID:19524162

  10. Percutaneous intracardiac beating-heart surgery using metal MEMS tissue approximation tools

    PubMed Central

    Gosline, Andrew H; Vasilyev, Nikolay V; Butler, Evan J; Folk, Chris; Cohen, Adam; Chen, Rich; Lang, Nora; del Nido, Pedro J; Dupont, Pierre E

    2013-01-01

    Achieving superior outcomes through the use of robots in medical applications requires an integrated approach to the design of the robot, tooling and the procedure itself. In this paper, this approach is applied to develop a robotic technique for closing abnormal communication between the atria of the heart. The goal is to achieve the efficacy of surgical closure as performed on a stopped, open heart with the reduced risk and trauma of a beating-heart catheter-based procedure. In the proposed approach, a concentric tube robot is used to percutaneously access the right atrium and deploy a tissue approximation device. The device is constructed using a metal microelectromechanical system (MEMS) fabrication process and is designed to both fit the manipulation capabilities of the robot as well as to reproduce the beneficial features of surgical closure by suture. The effectiveness of the approach is demonstrated through ex vivo and in vivo experiments. PMID:23750066

  11. Surgical ablation for atrial fibrillation: The efficacy of a novel bipolar pen device in the cardioplegically arrested and beating heart

    PubMed Central

    Sakamoto, Shun-ichiro; Voeller, Rochus K.; Melby, Spencer J.; Lall, Shelly C.; Chang, Nai-lun; Schuessler, Richard B.; Damiano, Ralph J.

    2009-01-01

    Objective The introduction of ablation technology has simplified surgical intervention for atrial fibrillation. However, most ablation devices cannot create focal transmural lesions on the beating heart and have difficulty ablating specific regions of the atria, such as the atrioventricular isthmus, coronary sinus, and ganglionated plexus. The purpose of this study was to examine the efficacy of a pen-type bipolar radiofrequency ablation device on both arrested and beating hearts. Methods Endocardial and epicardial atrial tissues in the free wall, left atrial roof, atrioventricular annuli, and coronary sinus were ablated for varying time intervals (2.5–15 seconds) in porcine cardioplegically arrested (n = 6) and beating (n = 9) hearts. The hearts were stained with 1%2,3,5-triphenyl-tetrazolium chloride solution and sectioned to determine lesion depth and width. In 5 animals epicardial fat pads containing ganglionated plexus were stimulated and ablated. Results Lesion depth increased with ablation time similarly in both arrested and beating hearts. Transmurality was fully achieved in the thin atrial tissue (<4 mm) at 10 seconds in the beating and arrested hearts. The device had a maximal penetration depth of 6.1 mm. Epicardial ablation of the coronary sinus showed complete penetration through the left posterior atrium only in the arrested heart. Seven of 17 fat pads demonstrated a vagal response. All vagal responses were eliminated after ablation. Conclusion The bipolar pen effectively ablated atrial tissue in both arrested and beating hearts. This device might allow the surgeon to ablate tissue in regions not accessible to other devices during atrial fibrillation surgery. PMID:19026819

  12. Doppler Beats or Interference Fringes?

    ERIC Educational Resources Information Center

    Kelly, Paul S.

    1979-01-01

    Discusses the following: another version of Doppler beats; alternate proof of spin-1 sin-1/2 problems; some mechanisms related to Dirac's strings; Doppler redshift in oblique approach of source and observer; undergraduate experiment on noise thermometry; use of the time evolution operator; resolution of an entropy maximization controversy;…

  13. And the Beat Goes On.

    ERIC Educational Resources Information Center

    Nardone, Jeff

    2002-01-01

    Advocates setting up a "beat system" for high school newspapers to use to provide updates on established areas of coverage, such as administrators, department chairs, club and class sponsors, sports, the school board, the city council and even the custodians. Includes examples of ways to incorporate this information into brief updates in student…

  14. NADPH- Diaphorase positive cardiac neurons in the atria of mice. A morphoquantitative study

    PubMed Central

    Maifrino, Laura Beatriz Mesiano; Liberti, Edson Aparecido; Castelucci, Patrícia; De Souza, Romeu Rodrigues

    2006-01-01

    Background The present study was conducted to determine the location, the morphology and distribution of NADPH-diaphorase positive neurons in the cardiac nerve plexus of the atria of mice (ASn). This plexus lies over the muscular layer of the atria, dorsal to the muscle itself, in the connective tissue of the subepicardium. NADPH- diaphorase staining was performed on whole-mount preparations of the atria mice. For descriptive purposes, all data are presented as means ± SEM. Results The majority of the NADPH-diaphorase positive neurons were observed in the ganglia of the plexus. A few single neurons were also observed. The number of NADPH-d positive neurons was 57 ± 4 (ranging from 39 to 79 neurons). The ganglion neurons were located in 3 distinct groups: (1) in the region situated cranial to the pulmonary veins, (2) caudally to the pulmonary veins, and (3) in the atrial groove. The largest group of neurons was located cranially to the pulmonary veins (66.7%). Three morphological types of NADPH-diaphorase neurons could be distinguished on the basis of their shape: unipolar cells, bipolar cells and cells with three processes (multipolar cells). The unipolar neurons predominated (78.9%), whereas the multipolar were encountered less frequently (5,3%). The sizes (area of maximal cell profile) of the neurons ranged from about 90 μm2to about 220 μm2. Morphometrically, the three types of neurons were similar and there were no significant differences in their sizes. The total number of cardiac neurons (obtained by staining the neurons with NADH-diaphorase method) was 530 ± 23. Therefore, the NADPH-diaphorase positive neurons of the heart represent 10% of the number of cardiac neurons stained by NADH. Conclusion The obtained data have shown that the NADPH-d positive neurons in the cardiac plexus of the atria of mice are morphologically different, and therefore, it is possible that the function of the neurons may also be different. PMID:16451738

  15. Twin heart with a fused atria and separate ventricles in conjoined twins

    PubMed Central

    Ambar, Sameer Suresh; Halkati, Prabhu C; Patted, Suresh V; Yavagal, ST

    2010-01-01

    One of the most interesting congenital malformations is that of conjoined twins. We report echocardiographic features of twin heart in dicephalus, tribrachius, dispinous, thoracoomphalopagus twin. It showed two hearts fused at atrial level. Right-sided heart had single atrial chamber with a single ventricle. A single great vessel, aorta, originated from it. Left-sided heart was well developed with two atria and two ventricles. There was a small mid muscular ventricular septal defect and a small patent ductus arteriosus. Great arteries had normal origins. PMID:21234207

  16. Musicians' Perception of Beat in Monotonic Stimuli.

    ERIC Educational Resources Information Center

    Duke, Robert A.

    1989-01-01

    Assesses musicians' perceptions of beat in monotonic stimuli and attempts to define empirically the range of perceived beat tempo in music. Subjects performed a metric pulse in response to periodic stimulus tones. Results indicate a relatively narrow range within which beats are perceived by trained musicians. (LS)

  17. Realtime Multichannel System for Beat to Beat QT Interval Variability

    NASA Technical Reports Server (NTRS)

    Starc, Vito; Schlegel, Todd T.

    2006-01-01

    The measurement of beat-to-beat QT interval variability (QTV) shows clinical promise for identifying several types of cardiac pathology. However, until now, there has been no device capable of displaying, in real time on a beattobeat basis, changes in QTV in all 12 conventional leads in a continuously monitored patient. While several software programs have been designed to analyze QTV, heretofore, such programs have all involved only a few channels (at most) and/or have required laborious user interaction or offline calculations and postprocessing, limiting their clinical utility. This paper describes a PC-based ECG software program that in real time, acquires, analyzes and displays QTV and also PQ interval variability (PQV) in each of the eight independent channels that constitute the 12lead conventional ECG. The system also processes certain related signals that are derived from singular value decomposition and that help to reduce the overall effects of noise on the realtime QTV and PQV results.

  18. Model-based imaging of cardiac electrical function in human atria

    NASA Astrophysics Data System (ADS)

    Modre, Robert; Tilg, Bernhard; Fischer, Gerald; Hanser, Friedrich; Messnarz, Bernd; Schocke, Michael F. H.; Kremser, Christian; Hintringer, Florian; Roithinger, Franz

    2003-05-01

    Noninvasive imaging of electrical function in the human atria is attained by the combination of data from electrocardiographic (ECG) mapping and magnetic resonance imaging (MRI). An anatomical computer model of the individual patient is the basis for our computer-aided diagnosis of cardiac arrhythmias. Three patients suffering from Wolff-Parkinson-White syndrome, from paroxymal atrial fibrillation, and from atrial flutter underwent an electrophysiological study. After successful treatment of the cardiac arrhythmia with invasive catheter technique, pacing protocols with stimuli at several anatomical sites (coronary sinus, left and right pulmonary vein, posterior site of the right atrium, right atrial appendage) were performed. Reconstructed activation time (AT) maps were validated with catheter-based electroanatomical data, with invasively determined pacing sites, and with pacing at anatomical markers. The individual complex anatomical model of the atria of each patient in combination with a high-quality mesh optimization enables accurate AT imaging, resulting in a localization error for the estimated pacing sites within 1 cm. Our findings may have implications for imaging of atrial activity in patients with focal arrhythmias.

  19. Beating phantasies: Mourned and unmourned.

    PubMed

    Antinucci, Giuseppina

    2016-06-01

    This paper intends to explore the organizing function and fate of sado-masochistic phantasies in their fixed form, in the psychic life of patients who have suffered early traumas, due to environmental vicissitudes and maternal psychopathology. The theoretical starting point is provided by the Novicks' research into transitory and permanent beating phantasies in adult and child patients, their onset and their psychic function, based on an examination of Freud's paper 'A child is being beaten'. In this text Freud achieves an unprecedented syncretism, locating the phantasy at the intersection between the oedipal complex, which is a vertical structure organizing sexual and generational differences, and the fraternal dimension, which is horizontal and organizes the lateral relationship with that similar but different other who is the sibling. Reporting in some detail material from the analyses of two young women, whose clinical presentation and early traumas show some similarities, the author puts in the context of the analytic work the emerging of the sado-masochistic phantasies, emphasizing their use and function in the transference-countertransference interplay. The beating phantasies shore up a precarious sense of self, threatened with psychic depletion and death, in identification with the absent mother of early infancy. An overly close relationship with a sibling, experienced as a narcissistic double, compounds the clinical picture, to establish the triangle formed by the parent(s) and two children which features in the beating phantasy. Finally, the author explores the contribution of ameliorating factors, such as alternative identificatory figures, constitutional endowment and capacity for sublimation, to account for the different fate of the fixed beating phantasies. PMID:26602362

  20. Plasma Beat-Wave Acceleration

    NASA Astrophysics Data System (ADS)

    Clayton, Christopher E.

    2002-04-01

    Among all the advanced accelerator concepts that use lasers as the power source, most of the effort to date has been with the idea of using a laser pulse to excite a accelerating mode in a plasma. Within this area, there are a variety of approaches for creating the accelerating mode, as indicated by the other talks in this session. What is common to these approaches is the physics of how a laser pulse pushes on plasma electrons to organize electron-density perturbations, the sources of the ultra-high (> GeV/M) accelerating gradients. It is the "ponderomotive force", proportional to the local gradient of the of the laser intensity, that pushes plasma electrons forward (on the leading edge of the pulse) and backwards (on the trailing edge) which leads to harmonic motion of the electrons. As the laser pulse moves through the plasma at group velocity Vg c, the oscillating electrons show up macroscopically as a plasma mode or wave with frequency w equal to the plasma frequency and k = w/Vg. For short laser pulses, this is the Laser Wakefield Accelerator (LWFA) concept. Closely related is the Plasma Beat-Wave Acceleration (PBWA) concept. Here, the laser pulse that perturbs the plasma is composed of two closely-spaced frequencies that "beat", i.e., periodically constructively and destructively interfere, forming an electromagnetic beat wave. One can visualize this as a train of short pulses. If this beating frequency is set to the plasma frequency, then each pulse in the train will reinforce the density perturbation caused by the previous pulse. The principal advantage of multiple pulses driving up the plasma wave as opposed to a single pulse is in efficiency, allowing for the production of relatively large diameter (more 1-D like) accelerating modes. In this talk I will discuss past, current and planned PBWA experiments which are taking place at UCLA, RAL in England, and LULI in France.

  1. GABAA receptor-mediated positive inotropism in guinea-pig isolated left atria: evidence for the involvement of capsaicin-sensitive nerves.

    PubMed Central

    Maggi, C. A.; Giuliani, S.; Manzini, S.; Meli, A.

    1989-01-01

    1. Isolated left atria from reserpine-pretreated guinea-pigs, electrically driven (3 Hz) in the presence of atropine (1 microM), phentolamine (0.3 microM) and propranolol (1 microM), responded to a train of stimuli (10 Hz for 2.5s) with a delayed neurogenic positive inotropic response which was insensitive to hexamethonium (10 microM) but abolished by either tetrodotoxin (1 microM), omega-conotoxin (0.1 microM), in vitro capsaicin desensitization or desensitization to calcitonin gene-related peptide (CGRP). 2. In these experimental conditions, gamma-aminobutyric acid (GABA) produced a concentration-related (10 microM-1 mM) positive inotropic response similar to that produced by electrical field stimulation. The effect of GABA was competitively antagonized by bicuculline methiodide (10 microM), a GABAA receptor antagonist. 3. The selective GABAA receptor agonists, muscimol and homotaurine mimicked the positive inotropic effect of GABA while baclofen, the selective GABAB receptor agonist, did not. 4. The action of GABA (1 mM) was abolished by either tetrodotoxin (1 microM), omega-conotoxin (0.1 microM), in vitro capsaicin desensitization or desensitization to CGRP, while it was unaffected by hexamethonium. In contrast, the inotropic response to CGRP was unaffected by tetrodotoxin, omega-conotoxin, bicuculline methiodide, hexamethonium or in vitro capsaicin desensitization, but was abolished by CGRP desensitization. 5. In the spontaneously beating guinea-pig right atrium, GABA (1 microM) produced a small and transient positive chronotropic effect that was no longer observed after in vitro desensitization with capsaicin (1 microM). 6. In the guinea-pig isolated perfused heart from reserpine-pretreated animals (with atropine, phentolamine and propranolol in the perfusion medium), GABA (1 microM) produced a transient tachycardia and a small increase in coronary flow.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2541852

  2. Losing the beat: deficits in temporal coordination

    PubMed Central

    Palmer, Caroline; Lidji, Pascale; Peretz, Isabelle

    2014-01-01

    Tapping or clapping to an auditory beat, an easy task for most individuals, reveals precise temporal synchronization with auditory patterns such as music, even in the presence of temporal fluctuations. Most models of beat-tracking rely on the theoretical concept of pulse: a perceived regular beat generated by an internal oscillation that forms the foundation of entrainment abilities. Although tapping to the beat is a natural sensorimotor activity for most individuals, not everyone can track an auditory beat. Recently, the case of Mathieu was documented (Phillips-Silver et al. 2011 Neuropsychologia 49, 961–969. (doi:10.1016/j.neuropsychologia.2011.02.002)). Mathieu presented himself as having difficulty following a beat and exhibited synchronization failures. We examined beat-tracking in normal control participants, Mathieu, and a second beat-deaf individual, who tapped with an auditory metronome in which unpredictable perturbations were introduced to disrupt entrainment. Both beat-deaf cases exhibited failures in error correction in response to the perturbation task while exhibiting normal spontaneous motor tempi (in the absence of an auditory stimulus), supporting a deficit specific to perception–action coupling. A damped harmonic oscillator model was applied to the temporal adaptation responses; the model's parameters of relaxation time and endogenous frequency accounted for differences between the beat-deaf cases as well as the control group individuals. PMID:25385783

  3. Losing the beat: deficits in temporal coordination.

    PubMed

    Palmer, Caroline; Lidji, Pascale; Peretz, Isabelle

    2014-12-19

    Tapping or clapping to an auditory beat, an easy task for most individuals, reveals precise temporal synchronization with auditory patterns such as music, even in the presence of temporal fluctuations. Most models of beat-tracking rely on the theoretical concept of pulse: a perceived regular beat generated by an internal oscillation that forms the foundation of entrainment abilities. Although tapping to the beat is a natural sensorimotor activity for most individuals, not everyone can track an auditory beat. Recently, the case of Mathieu was documented (Phillips-Silver et al. 2011 Neuropsychologia 49, 961-969. (doi:10.1016/j.neuropsychologia.2011.02.002)). Mathieu presented himself as having difficulty following a beat and exhibited synchronization failures. We examined beat-tracking in normal control participants, Mathieu, and a second beat-deaf individual, who tapped with an auditory metronome in which unpredictable perturbations were introduced to disrupt entrainment. Both beat-deaf cases exhibited failures in error correction in response to the perturbation task while exhibiting normal spontaneous motor tempi (in the absence of an auditory stimulus), supporting a deficit specific to perception-action coupling. A damped harmonic oscillator model was applied to the temporal adaptation responses; the model's parameters of relaxation time and endogenous frequency accounted for differences between the beat-deaf cases as well as the control group individuals. PMID:25385783

  4. Atrial fibrillation alters the microRNA expression profiles of the left atria of patients with mitral stenosis

    PubMed Central

    2014-01-01

    Background Structural changes of the left and right atria associated with atrial fibrillation (AF) in mitral stenosis (MS) patients are well known, and alterations in microRNA (miRNA) expression profiles of the right atria have also been investigated. However, miRNA changes in the left atria still require delineation. This study evaluated alterations in miRNA expression profiles of left atrial tissues from MS patients with AF relative to those with normal sinus rhythm (NSR). Methods Sample tissues from left atrial appendages were obtained from 12 MS patients (6 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Results were validated via reverse-transcription and quantitative PCR for 5 selected miRNAs. Potential miRNA targets were predicted and their functions and potential pathways analyzed via the miRFocus database. Results The expression levels of 22 miRNAs differed between the AF and NSR groups. Relative to NSR patients, in those with AF the expression levels of 45% (10/22) of these miRNAs were significantly higher, while those of the balance (55%, 12/22) were significantly lower. Potential miRNA targets and molecular pathways were identified. Conclusions AF alters the miRNA expression profiles of the left atria of MS patients. These findings may be useful for the biological understanding of AF in MS patients. PMID:24461008

  5. Influence of altered thyroid state on the interval-strength relationship of paced left atria of rats.

    PubMed

    Handberg, G M; Ishac, E J; Pennefather, J N

    1984-01-01

    Rats were treated with methimazole or thyroxine to render them either hypothyroid or hyperthyroid. Left atria from these animals and from control, untreated rats were isolated, placed in organ baths, and paced by direct electrical stimulation delivered via a punctate electrode. Contractile responses to trains of stimuli at 0.01-6 Hz were recorded isometrically. Atria from methimazole-treated rats required less voltage to elicit submaximal contractions; these were greater in magnitude and duration than those recorded from control preparations. The reverse was observed for preparations from hyperthyroid rats. Thyroid state had a marked influence upon the pattern of contractions elicited by trains of stimuli at varying frequencies. Atria from control rats displayed a typical negative interval-strength relationship, i.e., a decrease in contractile amplitude as the interval between stimuli in a train was decreased. This negative relationship was more pronounced in left atria from hypothyroid rats. In preparations from hyperthyroid rats, increases in stimulation frequency resulted in elevations in contractile amplitude. These observations are discussed in the light of known actions of thyroid hormone upon cardiac contractile mechanisms. PMID:6209503

  6. Simultaneous conduction mapping and intracellular membrane potential recording in isolated atria.

    PubMed

    Neo, Melissa; Morris, David G; Kuklik, Pawel; Lau, Dennis H; Dimitri, Hany; Lim, Wei-Wen; Sanders, Prashanthan; Saint, David A

    2016-05-01

    We describe a novel approach for simultaneously determining regional differences in action potential (AP) morphology and tissue electrophysiological properties in isolated atria. The epicardial surface of rat atrial preparations was placed in contact with a multi-electrode array (9 × 10 silver chloride electrodes, 0.1 mm diameter and 0.1 mm pitch). A glass microelectrode (100 MΩ) was simultaneously inserted into the endocardial surface to record intracellular AP from either of 2 regions (A, B) during pacing from 2 opposite corners of the tissue. AP duration at 80% of repolarisation and its restitution curve was significantly different only in region A (p < 0.01) when AP was initiated at different stimulation sites. Alternans in AP duration and AP amplitude, and in conduction velocity were observed during 2 separate arrhythmic episodes. This approach of combining microelectrode array and intracellular membrane potential recording may provide new insights into arrhythmogenic mechanisms in animal models of cardiovascular disease. PMID:26771118

  7. Systematic Analysis of Gene Expression Differences between Left and Right Atria in Different Mouse Strains and in Human Atrial Tissue

    PubMed Central

    Fabritz, Larissa; Greber, Boris; Schöler, Hans; Scheld, Hans H.; Hoffmeier, Andreas; Brown, Nigel A.; Kirchhof, Paulus

    2011-01-01

    Background Normal development of the atria requires left-right differentiation during embryonic development. Reduced expression of Pitx2c (paired-like homeodomain transcription factor 2, isoform c), a key regulator of left-right asymmetry, has recently been linked to atrial fibrillation. We therefore systematically studied the molecular composition of left and right atrial tissue in adult murine and human atria. Methods We compared left and right atrial gene expression in healthy, adult mice of different strains and ages by employing whole genome array analyses on freshly frozen atrial tissue. Selected genes with enriched expression in either atrium were validated by RT-qPCR and Western blot in further animals and in shock-frozen left and right atrial appendages of patients undergoing open heart surgery. Results We identified 77 genes with preferential expression in one atrium that were common in all strains and age groups analysed. Independent of strain and age, Pitx2c was the gene with the highest enrichment in left atrium, while Bmp10, a member of the TGFβ family, showed highest enrichment in right atrium. These differences were validated by RT-qPCR in murine and human tissue. Western blot showed a 2-fold left-right concentration gradient in PITX2 protein in adult human atria. Several of the genes and gene groups enriched in left atria have a known biological role for maintenance of healthy physiology, specifically the prevention of atrial pathologies involved in atrial fibrillation, including membrane electrophysiology, metabolic cellular function, and regulation of inflammatory processes. Comparison of the array datasets with published array analyses in heterozygous Pitx2c+/− atria suggested that approximately half of the genes with left-sided enrichment are regulated by Pitx2c. Conclusions Our study reveals systematic differences between left and right atrial gene expression and supports the hypothesis that Pitx2c has a functional role in maintaining

  8. Bondage fantasies and beating fantasies.

    PubMed

    Weiss, J

    1998-10-01

    Two male patients had masochistic sexual fantasies: one had bondage fantasies, the other beating fantasies. Each patient had been traumatized in childhood by his experiences with a martyr mother. Each had developed the belief that in an intimate sexual relationship with a woman he would hurt her. As a consequence, each tended to suppress his sexuality. Each used masochistic fantasies to reassure himself that he was not hurting his fantasied or real partner. The reassurance made it safe to experience his sexual feelings. The two patients' use of their masochistic fantasies is compared to the fetishist's use of his fetish, as described by Freud. PMID:9820894

  9. Nonlinear beat Cepheid and RR Lyrae models

    NASA Astrophysics Data System (ADS)

    Kolláth, Z.; Buchler, J. R.; Szabó, R.; Csubry, Z.

    2002-04-01

    The numerical hydrodynamic modelling of beat Cepheid behavior has been a long-standing quest in which purely radiative models have failed consistently. We find that beat pulsations occur quite naturally when turbulent convection is accounted for in our hydrodynamics code. The developments of a relaxation code and of a Floquet stability analysis greatly facilitate the search for and the analysis of beat Cepheid models. The conditions for the occurrence of beat behavior can be understood easily and at a fundamental level with the help of amplitude equations.

  10. The Simplest Demonstration on Acoustic Beats

    ERIC Educational Resources Information Center

    Ganci, Alessio; Ganci, Salvatore

    2015-01-01

    The classical demonstration experiment on acoustic beats using two signal generators and a dual trace oscilloscope is an important ingredient in teaching the subject. This short laboratory note aims to point out what may be the simplest demonstrative experiment on acoustic beats to carry out in a classroom without employing any lab apparatus.

  11. Non Heart-Beating Donors in England

    PubMed Central

    Chaib, Eleazar

    2008-01-01

    When transplantation started all organs were retrieved from patients immediately after cardio-respiratory arrest, i.e. from non-heart-beating donors. After the recognition that death resulted from irreversible damage to the brainstem, organ retrieval rapidly switched to patients certified dead after brainstem testing. These heart-beating-donors have become the principal source of organs for transplantation for the last 30 years. The number of heart-beating-donors are declining and this is likely to continue, therefore cadaveric organs from non-heart-beating donor offers a large potential of resources for organ transplantation. The aim of this study is to examine clinical outcomes of non-heart-beating donors in the past 10 years in the UK as an way of decreasing pressure in the huge waiting list for organs transplantation. PMID:18297216

  12. Rhythmicity, recurrence, and recovery of flagellar beating

    NASA Astrophysics Data System (ADS)

    Wan, Kirsty; Goldstein, Raymond

    2015-03-01

    The eukaryotic flagellum beats with apparently unfailing periodicity, yet responds rapidly to stimuli. Like the human heartbeat, flagellar oscillations are now known to be noisy. Using the unicellular alga Chlamydomonas reinhardtii, we explore three aspects of nonuniform flagellar beating. We report the existence of rhythmicity, waveform noise peaking at transitions between power and recovery strokes, and fluctuations of interbeat intervals that are correlated and even recurrent, with memory extending to hundreds of beats. These features are altered qualitatively by physiological perturbations. Further, we quantify the recovery of periodic breaststroke beating from transient hydrodynamic forcing. These results will help constrain microscopic theories on the origins and regulation of flagellar beating. Financial support is acknowledged from the EPSRC, ERC Advanced Investigator Grant No. 247333, and a Senior Investigator Award from the Wellcome Trust.

  13. Elastic interactions synchronize beating in cardiomyocytes.

    PubMed

    Cohen, Ohad; Safran, Samuel A

    2016-07-13

    Motivated by recent experimental results, we study theoretically the synchronization of the beating phase and frequency of two nearby cardiomyocyte cells. Each cell is represented as an oscillating force dipole in an infinite, viscoelastic medium and the propagation of the elastic signal within the medium is predicted. We examine the steady-state beating of two nearby cells, and show that elastic interactions result in forces that synchronize the phase and frequency of beating in a manner that depends on their mutual orientation. The theory predicts both in-phase and anti-phase steady-state beating depending on the relative cell orientations, as well as how synchronized beating varies with substrate elasticity and the inter-cell distance. These results suggest how mechanics plays a role in cardiac efficiency, and may be relevant for the design of cardiomyocyte based micro devices and other biomedical applications. PMID:27352146

  14. Collective beating of artificial microcilia.

    PubMed

    Coq, Naïs; Bricard, Antoine; Delapierre, Francois-Damien; Malaquin, Laurent; du Roure, Olivia; Fermigier, Marc; Bartolo, Denis

    2011-07-01

    We combine technical, experimental, and theoretical efforts to investigate the collective dynamics of artificial microcilia in a viscous fluid. We take advantage of soft lithography and colloidal self-assembly to devise microcarpets made of hundreds of slender magnetic rods. This novel experimental setup is used to investigate the dynamics of extended cilia arrays driven by a precessing magnetic field. Whereas the dynamics of an isolated cilium is a rigid body rotation, collective beating results in a symmetry breaking of the precession patterns. The trajectories of the cilia are anisotropic and experience a significant structural evolution as the actuation frequency increases. We present a minimal model to account for our experimental findings and demonstrate how the global geometry of the array imposes the shape of the trajectories via long-range hydrodynamic interactions. PMID:21797546

  15. Analyzing the acoustic beat with mobile devices

    NASA Astrophysics Data System (ADS)

    Kuhn, Jochen; Vogt, Patrik; Hirth, Michael

    2014-04-01

    In this column, we have previously presented various examples of how physical relationships can be examined by analyzing acoustic signals using smartphones or tablet PCs. In this example, we will be exploring the acoustic phenomenon of small beats, which is produced by the overlapping of two tones with a low difference in frequency Δf. The resulting auditory sensation is a tone with a volume that varies periodically. Acoustic beats can be perceived repeatedly in day-to-day life and have some interesting applications. For example, string instruments are still tuned with the help of an acoustic beat, even with modern technology. If a reference tone (e.g., 440 Hz) and, for example, a slightly out-of-tune violin string produce a tone simultaneously, a beat can be perceived. The more similar the frequencies, the longer the duration of the beat. In the extreme case, when the frequencies are identical, a beat no longer arises. The string is therefore correctly tuned. Using the Oscilloscope app,4 it is possible to capture and save acoustic signals of this kind and determine the beat frequency fS of the signal, which represents the difference in frequency Δf of the two overlapping tones (for Android smartphones, the app OsciPrime Oscilloscope can be used).

  16. Electrical Brain Responses to Beat Irregularities in Two Cases of Beat Deafness.

    PubMed

    Mathias, Brian; Lidji, Pascale; Honing, Henkjan; Palmer, Caroline; Peretz, Isabelle

    2016-01-01

    Beat deafness, a recently documented form of congenital amusia, provides a unique window into functional specialization of neural circuitry for the processing of musical stimuli: Beat-deaf individuals exhibit deficits that are specific to the detection of a regular beat in music and the ability to move along with a beat. Studies on the neural underpinnings of beat processing in the general population suggest that the auditory system is capable of pre-attentively generating a predictive model of upcoming sounds in a rhythmic pattern, subserved largely within auditory cortex and reflected in mismatch negativity (MMN) and P3 event-related potential (ERP) components. The current study examined these neural correlates of beat perception in two beat-deaf individuals, Mathieu and Marjorie, and a group of control participants under conditions in which auditory stimuli were either attended or ignored. Compared to control participants, Mathieu demonstrated reduced behavioral sensitivity to beat omissions in metrical patterns, and Marjorie showed a bias to identify irregular patterns as regular. ERP responses to beat omissions reveal an intact pre-attentive system for processing beat irregularities in cases of beat deafness, reflected in the MMN component, and provide partial support for abnormalities in later cognitive stages of beat processing, reflected in an unreliable P3b component exhibited by Mathieu-but not Marjorie-compared to control participants. P3 abnormalities observed in the current study resemble P3 abnormalities exhibited by individuals with pitch-based amusia, and are consistent with attention or auditory-motor coupling accounts of deficits in beat perception. PMID:26941591

  17. Electrical Brain Responses to Beat Irregularities in Two Cases of Beat Deafness

    PubMed Central

    Mathias, Brian; Lidji, Pascale; Honing, Henkjan; Palmer, Caroline; Peretz, Isabelle

    2016-01-01

    Beat deafness, a recently documented form of congenital amusia, provides a unique window into functional specialization of neural circuitry for the processing of musical stimuli: Beat-deaf individuals exhibit deficits that are specific to the detection of a regular beat in music and the ability to move along with a beat. Studies on the neural underpinnings of beat processing in the general population suggest that the auditory system is capable of pre-attentively generating a predictive model of upcoming sounds in a rhythmic pattern, subserved largely within auditory cortex and reflected in mismatch negativity (MMN) and P3 event-related potential (ERP) components. The current study examined these neural correlates of beat perception in two beat-deaf individuals, Mathieu and Marjorie, and a group of control participants under conditions in which auditory stimuli were either attended or ignored. Compared to control participants, Mathieu demonstrated reduced behavioral sensitivity to beat omissions in metrical patterns, and Marjorie showed a bias to identify irregular patterns as regular. ERP responses to beat omissions reveal an intact pre-attentive system for processing beat irregularities in cases of beat deafness, reflected in the MMN component, and provide partial support for abnormalities in later cognitive stages of beat processing, reflected in an unreliable P3b component exhibited by Mathieu—but not Marjorie—compared to control participants. P3 abnormalities observed in the current study resemble P3 abnormalities exhibited by individuals with pitch-based amusia, and are consistent with attention or auditory-motor coupling accounts of deficits in beat perception. PMID:26941591

  18. Myocardial steatosis and necrosis in atria and ventricles of rats given pyruvate dehydrogenase kinase inhibitors.

    PubMed

    Jones, Huw Bowen; Reens, Jaimini; Johnson, Elizabeth; Brocklehurst, Simon; Slater, Ian

    2014-12-01

    Pharmaceutical therapies for non-insulin-dependent diabetes mellitus (NIDDM) include plasma glucose lowering by enhancing glucose utilization. The mitochondrial pyruvate dehydrogenase (PDH) complex is important in controlling the balance between glucose and fatty acid substrate oxidation. Administration of pyruvate dehydrogenase kinase inhibitors (PDHKIs) to rats effectively lowers plasma glucose but results in myocardial steatosis that in some instances is associated primarily with atrial and to a lesser degree with ventricular pathology. Induction of myocardial steatosis is not dose-dependent, varies from minimal to moderate severity, and is either of multifocal or diffuse distribution. Ventricular histopathology was restricted to few myocardial degenerative fibers, while that in the atrium/atria was of either acute or chronic appearance with the former showing myocardial degeneration/necrosis, acute myocarditis, edema, endothelial activation (rounding up), endocarditis, and thrombosis associated with moderate myocardial steatosis and the latter with myocardial loss, replacement fibrosis, and no apparent or minimal association with steatosis. The evidence from these evaluations indicate that excessive intramyocardial accumulation of lipid may be either primarily adverse or represents an indicator of other adversely affected cellular processes. PMID:24742628

  19. A two layers monodomain model of cardiac electrophysiology of the atria.

    PubMed

    Coudière, Yves; Henry, Jacques; Labarthe, Simon

    2015-12-01

    Numerical simulations of the cardiac electrophysiology in the atria are often based on the standard bidomain or monodomain equations stated on a two-dimensional manifold. These simulations take advantage of the thinness of the atrial tissue, and their computational cost is reduced, as compared to three-dimensional simulations. However, these models do not take into account the heterogeneities located in the thickness of the tissue, like discontinuities of the fiber direction, although they can be a substrate for atrial arrhythmia (Hocini et al., Circulation 105(20):2442-2448, 2002; Ho et al., Cardiovasc Res 54(2):325-336, 2002; Nattel, Nature 415(6868):219-226, 2002). We investigate a two-dimensional model with two coupled, superimposed layers that allows to introduce three-dimensional heterogeneities, but retains a reasonable computational cost. We introduce the mathematical derivation of this model and error estimates with respect to the three-dimensional model. We give some numerical illustrations of its interest: we numerically show its convergence for vanishing thickness, introduce an optimization process of the coupling coefficient and assess its validity on physiologically relevant geometries. Our model would be an efficient tool to test the influence of three-dimensional fiber direction heterogeneities in reentries or atrial arrhythmia without using three-dimensional models. PMID:25773466

  20. Study of atrial arrhythmias in a computer model based on magnetic resonance images of human atria

    NASA Astrophysics Data System (ADS)

    Virag, N.; Jacquemet, V.; Henriquez, C. S.; Zozor, S.; Blanc, O.; Vesin, J.-M.; Pruvot, E.; Kappenberger, L.

    2002-09-01

    The maintenance of multiple wavelets appears to be a consistent feature of atrial fibrillation (AF). In this paper, we investigate possible mechanisms of initiation and perpetuation of multiple wavelets in a computer model of AF. We developed a simplified model of human atria that uses an ionic-based membrane model and whose geometry is derived from a segmented magnetic resonance imaging data set. The three-dimensional surface has a realistic size and includes obstacles corresponding to the location of major vessels and valves, but it does not take into account anisotropy. The main advantage of this approach is its ability to simulate long duration arrhythmias (up to 40 s). Clinically relevant initiation protocols, such as single-site burst pacing, were used. The dynamics of simulated AF were investigated in models with different action potential durations and restitution properties, controlled by the conductance of the slow inward current in a modified Luo-Rudy model. The simulation studies show that (1) single-site burst pacing protocol can be used to induce wave breaks even in tissue with uniform membrane properties, (2) the restitution-based wave breaks in an atrial model with realistic size and conduction velocities are transient, and (3) a significant reduction in action potential duration (even with apparently flat restitution) increases the duration of AF.

  1. Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation

    PubMed Central

    Ferrer, Ana; Sebastián, Rafael; Sánchez-Quintana, Damián; Rodríguez, José F.; Godoy, Eduardo J.; Martínez, Laura; Saiz, Javier

    2015-01-01

    Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study the relationship between atrial activation and surface signals in sinus rhythm. Using this multi scale model, it was revealed that the best places for recording P-waves are the frontal upper right and the frontal and rear left quadrants of the torso. Our results also suggest that only nine regions (of the twenty-one structures in which the atrial surface was divided) make a significant contribution to the BSPM and determine the main P-wave characteristics. PMID:26523732

  2. Study of atrial arrhythmias in a computer model based on magnetic resonance images of human atria.

    PubMed

    Virag, N.; Jacquemet, V.; Henriquez, C. S.; Zozor, S.; Blanc, O.; Vesin, J.-M.; Pruvot, E.; Kappenberger, L.

    2002-09-01

    The maintenance of multiple wavelets appears to be a consistent feature of atrial fibrillation (AF). In this paper, we investigate possible mechanisms of initiation and perpetuation of multiple wavelets in a computer model of AF. We developed a simplified model of human atria that uses an ionic-based membrane model and whose geometry is derived from a segmented magnetic resonance imaging data set. The three-dimensional surface has a realistic size and includes obstacles corresponding to the location of major vessels and valves, but it does not take into account anisotropy. The main advantage of this approach is its ability to simulate long duration arrhythmias (up to 40 s). Clinically relevant initiation protocols, such as single-site burst pacing, were used. The dynamics of simulated AF were investigated in models with different action potential durations and restitution properties, controlled by the conductance of the slow inward current in a modified Luo-Rudy model. The simulation studies show that (1) single-site burst pacing protocol can be used to induce wave breaks even in tissue with uniform membrane properties, (2) the restitution-based wave breaks in an atrial model with realistic size and conduction velocities are transient, and (3) a significant reduction in action potential duration (even with apparently flat restitution) increases the duration of AF. (c) 2002 American Institute of Physics. PMID:12779604

  3. Influence of age on inducibility and cholinergic modulation of arrhythmia in isolated rat right atria.

    PubMed

    Faria, D M; Viviane, A G; Galvão, K M; Caricati-Neto, A; Godoy, C M G

    2009-03-01

    The effects of carbachol and atropine on the number of trains (NT) and on the train stimulus strength (SS) necessary to induce arrhythmia were studied in isolated right atria of infant, young, adult and mature rats submitted to electric field stimulation (66.7 Hz, 5 ms pulse-duration, 250 pulses). Carbachol (1 microM) decreased NT from four (control) to two in all ages tested. Atropine (1 microM) prevented tachyarrhythmia induction in tissue of all ages, even with NT equal to 12, except for mature rats (typically four trains). The SS decreases from infant to adult age [5- to 2-fold atrial threshold (AT)] and increases in mature animals (5-fold AT). Carbachol changes this result only for mature rats (5- to 2-fold AT). The SS was decreased by carbachol (1 microM) from 5- to 3-fold AT in mature rats, but atropine did not modify SS in this age. These results indicate that inducibility and cholinergic modulation of atrial tachyarrhythmia is influenced by age. PMID:19234768

  4. Dynamic focusing in the zebrafish beating heart

    NASA Astrophysics Data System (ADS)

    Andrés-Delgado, L.; Peralta, M.; Mercader, N.; Ripoll, J.

    2016-03-01

    Of the large amount of the animal models available for cardiac research, the zebrafish is extremely valuable due to its transparency during early stages of development. In this work a dual illumination laser sheet microscope with simultaneous dual camera imaging is used to image the beating heart at 200 fps, dynamically and selectively focusing inside the beating heart through the use of a tunable lens. This dual color dynamic focusing enables imaging with cellular resolution at unprecedented high frame rates, allowing 3D imaging of the whole beating heart of embryonic zebrafish.

  5. Autoresonant beat-wave generation

    SciTech Connect

    Lindberg, R. R.; Charman, A. E.; Wurtele, J. S.; Friedland, L.; Shadwick, B. A.

    2006-12-15

    Autoresonance offers an efficient and robust means for the ponderomotive excitation of nonlinear Langmuir waves by phase-locking of the plasma wave to the slowly chirped beat frequency of the driving lasers via adiabatic passage through resonance. This mechanism is analyzed for the case of a cold, relativistic, underdense electron plasma, and its suitability for particle acceleration is discussed. Compared to traditional approaches, this new autoresonant scheme achieves larger accelerating electric fields for given laser intensity; the plasma wave excitation is much more robust to variations in plasma density; it is largely insensitive to the precise choice of chirp rate, provided only that it is sufficiently slow; and the suitability of the resulting plasma wave for accelerator applications is, in some respects, superior. As in previous schemes, modulational instabilities of the ionic background ultimately limit the useful interaction time, but nevertheless peak electric fields approaching the wave-breaking limit seem readily attainable. The total frequency shift required is only of the order of a few percent of the laser carrier frequency, and might be implemented with relatively little additional modification to existing systems based on chirped pulse amplification techniques, or, with somewhat greater technological effort, using a CO{sub 2} or other gas laser system.

  6. Beating kinematics of magnetically actuated cilia

    NASA Astrophysics Data System (ADS)

    Downton, M. T.; Stark, H.

    2009-02-01

    We study the beating kinematics and pumping performance of a magnetically actuated artificial cilium attached to a surface using a bead spring model. Several different beating patterns for the external field are considered along with the possiblity of defects in the filament at isolated points. Hydrodynamic interactions between the beads are included by a modified Rotne-Prage tensor such that the no-slip boundary condition at the surface is satisfied. We find that the correct positioning of defects along the filament length can lead to significant increases in the pumping performance of a planar beating pattern. Even more efficient for pumping fluid are three-dimensional beating strokes which bring the filament close to the surface during the return part of the stroke.

  7. People Interview: Engineering beats Pisa's problem

    NASA Astrophysics Data System (ADS)

    2009-05-01

    INTERVIEW Engineering beats Pisa's problem John Burland has been professor of soil mechanics at Imperial College London for 20 years and is recognized as a distinguished figure in geotechnical engineering. David Smith talks to him about his work.

  8. Beating Depression …Help Is Available

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues Beating Depression …Help Is Available Past Issues / Summer 2007 Table ... treatments are available from your physician. Types of Depression Just like other illnesses, such as heart disease, ...

  9. Structure-activity relationship of imidazolidine derivatives related to clonidine at histamine H2-receptors in guinea-pig isolated atria

    PubMed Central

    McCulloch, M.W.; Medgett, I.C.; Rand, M.J.; Story, D.F.

    1980-01-01

    1 Cumulative concentration-response relationships for the chronotropic effects of histamine, oxymetazoline, clonidine and thirteen clonidine-like imidazolidine derivatives were examined in isolated spontaneously beating guinea-pig atria. 2 The following compounds induced positive chronotropic effects: histamine, clonidine (2,6-dichloro-phenyliminoimidazolidine) and the 2,6-dibromo, 2,6-dimethyl, 2,6-diethyl, 2,6-dihydroxy, 2,4,6-trimethyl, 3,4-dihydroxy and 2-methyl-5-fluoro analogues of clonidine. These compounds appeared to act as partial agonists on histamine H2-receptors, with potencies ranging from one tenth to one hundredth and intrinsic activities from approximately 20% to 75% of those of histamine. 3 The following compounds did not induce positive chronotropic effects but rather decreased the atrial rate, usually at high concentrations: oxymetazoline and the 2,3-dichloro, 4-dichloro, 5-dichloro, 2-chloro-4-methyl, 2-methyl-5-chloro, 2,4,6-trichloro analogues of clonidine. 4 The effects of histamine were antagonized by cimetidine, the pA2 value being 6.68 (s.e. mean = 0.16, n = 3), and also in a concentration-dependent manner by clonidine. Cimetidine antagonized the response to clonidine in a concentration-dependent manner; however, high concentrations of cimetidine depressed the maximal response to clonidine and the slope of the concentration-response curve was no longer parallel to the control curve. 5 The effects of the other compounds which induced positive chronotropic effects were also antagonized by cimetidine (1 μmol/l); however, the effect of the 3,4-dihydroxy derivative was unaffected by cimetidine (1 μmol/l) but was abolished by propranolol (0.3 μmol/l). 6 In general, phenyliminoimidazolidine derivatives with 2,6-substitution on the phenyl ring are active on histamine H2-receptors, whereas derivatives with 2,3-, 2,4- or 2,5-substitutions are weakly active or inactive. Thus the restriction imposed on the free rotation of the phenyl ring about

  10. Why does the heart beat? The discovery of the electrical system of the heart.

    PubMed

    Silverman, Mark E; Grove, Daniel; Upshaw, Charles B

    2006-06-13

    Why does the heart beat? This question--known as the myogenic versus neurogenic theory--dominated cardiac research in the 19th century. In 1839, Jan Evangelista Purkinje discovered gelatinous fibers in the ventricular subendocardium that he thought were muscular. Walter Gaskell, in 1886, demonstrated specialized muscle fibers joining the atria and ventricles that caused "block" when cut and found that the sinus venosus was the area of first excitation of the heart. By examining serial embryologic sections, Wilhelm His, Jr, showed that a connective tissue sheet became a bundle connecting the upper and lower cardiac chambers, the bundle of His. Sunao Tawara traced the atrioventricular (AV) bundle of His backward to find a compact node of fibers at the base of the atrial septum and forward where it connected with the bundles of cells discovered by Purkinje in 1839. Tawara concluded that this "AV connecting system" originated in the AV node, penetrated the septum as the His bundle, and then divided into left and right bundle branches that terminated in the Purkinje fibers. Martin Flack and Arthur Keith studied the conduction system of a mole and found a structure in the sinoauricular junction that histologically resembled the AV node. They felt that this was where "the dominating rhythm of the heart normally begins" and named it the sinoauricular node in 1907. The ECG of Einthoven soon brought a new understanding to the complex electrical system that makes the heart beat. In 2006 and 2007, we celebrate the 100th anniversaries of the publication of the exciting discovery of the AV and sinus nodes, truly landmarks in our understanding of cardiac structure and physiology. PMID:16769927

  11. Viral infections of rabbits.

    PubMed

    Kerr, Peter J; Donnelly, Thomas M

    2013-05-01

    Viral diseases of rabbits have been used historically to study oncogenesis (e.g. rabbit fibroma virus, cottontail rabbit papillomavirus) and biologically to control feral rabbit populations (e.g. myxoma virus). However, clinicians seeing pet rabbits in North America infrequently encounter viral diseases although myxomatosis may be seen occasionally. The situation is different in Europe and Australia, where myxomatosis and rabbit hemorrhagic disease are endemic. Advances in epidemiology and virology have led to detection of other lapine viruses that are now recognized as agents of emerging infectious diseases. Rabbit caliciviruses, related to rabbit hemorrhagic disease, are generally avirulent, but lethal variants are being identified in Europe and North America. Enteric viruses including lapine rotavirus, rabbit enteric coronavirus and rabbit astrovirus are being acknowledged as contributors to the multifactorial enteritis complex of juvenile rabbits. Three avirulent leporid herpesviruses are found in domestic rabbits. A fourth highly pathogenic virus designated leporid herpesvirus 4 has been described in Canada and Alaska. This review considers viruses affecting rabbits by their clinical significance. Viruses of major and minor clinical significance are described, and viruses of laboratory significance are mentioned. PMID:23642871

  12. Beliefs of Sri Lankan Medical Students about Wife Beating

    ERIC Educational Resources Information Center

    Haj-Yahia, Muhammad M.; de Zoysa, Piyanjali

    2007-01-01

    The article presents the results of a study on beliefs about wife beating conducted among 476 Sri Lankan medical students. Participants fill out a self-administered questionnaire, which examines six beliefs about wife beating. Most students tend to justify wife beating, to believe women benefit from wife beating, and to believe the wife bears more…

  13. Atrial distension of isolated rabbit hearts and release of atrial natriuretic factor

    SciTech Connect

    Synhorst, D.P.; Gutkowska, J. Clinical Research Institute of Montreal, Quebec )

    1988-08-01

    Interventions that increase atrial pressures in humans or laboratory animals release atrial natriuretic factor (ANF) into the circulation. The authors studied the relation between distension of the right or left atrium and release of ANF in retrograde-perfused isolated rabbit hearts. A fluid-filled balloon within the right or left atrium was inflated to a mean pressure of 5, 10, 15, or 20 mmHg, and ANF in the cardiac effluent was measured by radioimmunoassay. The slope of the regression line relating ANF release to atrial distending pressure was steeper for the left than right atrium, indicating that, at comparable increases in mean pressures, the left atrium releases more ANF than does the right atrium. Left atrial tissue concentration ANF was greater than right atrial. In contrast to previous studies showing right atrial dominance in rats, the left atria of isolated, perfused rabbit hearts contain more ANF and release more in response to atrial distension.

  14. Audiovisual beat induction in complex auditory rhythms: point-light figure movement as an effective visual beat.

    PubMed

    Su, Yi-Huang

    2014-09-01

    This study investigated whether explicit beat induction in the auditory, visual, and audiovisual (bimodal) modalities aided the perception of weakly metrical auditory rhythms, and whether it reinforced attentional entrainment to the beat of these rhythms. The visual beat-inducer was a periodically bouncing point-light figure, which aimed to examine whether an observed rhythmic human movement could induce a beat that would influence auditory rhythm perception. In two tasks, participants listened to three repetitions of an auditory rhythm that were preceded and accompanied by (1) an auditory beat, (2) a bouncing point-light figure, (3) a combination of (1) and (2) synchronously, or (4) a combination of (1) and (2), with the figure moving in anti-phase to the auditory beat. Participants reproduced the auditory rhythm subsequently (Experiment 1), or detected a possible temporal change in the third repetition (Experiment 2). While an explicit beat did not improve rhythm reproduction, possibly due to the syncopated rhythms when a beat was imposed, bimodal beat induction yielded greater sensitivity to a temporal deviant in on-beat than in off-beat positions. Moreover, the beat phase of the figure movement determined where on-beat accents were perceived during bimodal induction. Results are discussed with regard to constrained beat induction in complex auditory rhythms, visual modulation of auditory beat perception, and possible mechanisms underlying the preferred visual beat consisting of rhythmic human motions. PMID:24932996

  15. The impact of binaural beats on creativity

    PubMed Central

    Reedijk, Susan A.; Bolders, Anne; Hommel, Bernhard

    2013-01-01

    Human creativity relies on a multitude of cognitive processes, some of which are influenced by the neurotransmitter dopamine. This suggests that creativity could be enhanced by interventions that either modulate the production or transmission of dopamine directly, or affect dopamine-driven processes. In the current study we hypothesized that creativity can be influenced by means of binaural beats, an auditory illusion that is considered a form of cognitive entrainment that operates through stimulating neuronal phase locking. We aimed to investigate whether binaural beats affect creative performance at all, whether they affect divergent thinking, convergent thinking, or both, and whether possible effects may be mediated by the individual striatal dopamine level. Binaural beats were presented at alpha and gamma frequency. Participants completed a divergent and a convergent thinking task to assess two important functions of creativity, and filled out the Positive And Negative Affect Scale—mood State questionnaire (PANAS-S) and an affect grid to measure current mood. Dopamine levels in the striatum were estimated using spontaneous eye blink rates (EBRs). Results showed that binaural beats, regardless of the presented frequency, can affect divergent but not convergent thinking. Individuals with low EBRs mostly benefitted from alpha binaural beat stimulation, while individuals with high EBRs were unaffected or even impaired by both alpha and gamma binaural beats. This suggests that binaural beats, and possibly other forms of cognitive entrainment, are not suited for a one-size-fits-all approach, and that individual cognitive-control systems need to be taken into account when studying cognitive enhancement methods. PMID:24294202

  16. Positive inotropic effect of the inhibition of cyclic GMP-stimulated 3',5'-cyclic nucleotide phosphodiesterase (PDE2) on guinea pig left atria in eu- and hyperthyroidism.

    PubMed

    Gesztelyi, R; Zsuga, J; Hajdú, P; Szabó, J Zs; Cseppento, A; Szentmiklósi, A J

    2003-12-01

    The significance of PDE2 on the atrial inotropy was studied in eu- and hyperthyroidism. The contractile force was measured and negative inotropic capacity of N6-cyclopentyladenosine (CPA) was determined on left atria isolated from 8-day thyroxine- or solvent-treated guinea pigs, in the presence or absence of EHNA (adenosine deaminase and PDE2 inhibitor) or NBTI (nucleoside transporter inhibitor). EHNA was administered to inhibit PDE2, while NBTI was used to model the accumulation of endogenous adenosine. The reduction of the contractile force caused by EHNA was smaller in the thyroxine-treated atria than in the solvent-treated samples. Contrary, NBTI induced a decrease in the contractile force without significant difference between the two groups. In addition, EHNA enhanced the efficiency of CPA in thyroxine-treated atria and did not affect it in solvent-treated samples, while the response to CPA was decreased by NBTI in all atria, especially in hyperthyroidism. On the basis of greater retention of the contractile force and sustained/enhanced responsiveness to CPA in the presence of EHNA we conclude that PDE2's inhibition has a significant positive inotropic effect in guinea pig atria and this effect is proven to be augmented in hyperthyroidism. PMID:15113122

  17. Evidence that M1 muscarinic receptors enhance noradrenaline release in mouse atria by activating protein kinase C.

    PubMed Central

    Costa, M.; Barrington, M.; Majewski, H.

    1993-01-01

    1. The M1 selective muscarinic agonist, McNeil A 343, enhanced the electrically evoked release of noradrenaline from postganglionic sympathetic nerves in mouse atria. This has been found previously to be due to activation of muscarinic receptors of the M1 subtype, probably located on sympathetic nerve terminals. The present study investigated the signal transduction mechanisms involved in the release-enhancing effects of McNeil A 343. The release of noradrenaline from mouse atria was assessed by measuring the electrically-induced (3 Hz, 60 s) outflow of radioactivity from atria which had been pre-incubated with [3H]-noradrenaline. 2. 8-Bromo cyclic AMP in the presence of IBMX was used to enhance maximally S-I noradrenaline release through cyclic AMP-dependent mechanisms. However, the facilitatory effect of McNeil A 343 (10 microM) was not different from the effect in the absence of these drugs, suggesting that McNeil A 343 enhances noradrenaline release independently of the cyclic AMP system. Furthermore, the release-enhancing effect of McNeil A 343 (10 microM) on noradrenaline release was also not altered by the 5-lipoxygenase inhibitor, BW A4C. 3. The facilitatory effect of McNeil A 343 was not altered in the presence of drugs (trifluoperazine, W7, and calmidazolium) which inhibit calmodulin-dependent processes, suggesting that the mechanisms of action of McNeil A 343 does not depend on calmodulin. 4. It was considered likely that the facilitatory effect of McNeil A 343 on noradrenaline release may be due to activation of protein kinase C, since activators of protein kinase C enhance noradrenaline release.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7694761

  18. Pro-arrhythmogenic effects of atrial fibrillation-induced electrical remodelling: insights from the three-dimensional virtual human atria.

    PubMed

    Colman, Michael A; Aslanidi, Oleg V; Kharche, Sanjay; Boyett, Mark R; Garratt, Clifford; Hancox, Jules C; Zhang, Henggui

    2013-09-01

    Chronic atrial fibrillation (AF) is associated with structural and electrical remodelling in the atria, which are associated with a high recurrence of AF. Through biophysically detailed computer modelling, this study investigated mechanisms by which AF-induced electrical remodelling promotes and perpetuates AF. A family of Courtemanche-Ramirez-Nattel variant models of human atrial cell action potentials (APs), taking into account of intrinsic atrial electrophysiological properties, was modified to incorporate various experimental data sets on AF-induced changes of major ionic channel currents (ICaL, IKur, Ito, IK1, IKs, INaCa) and on intracellular Ca(2+) handling. The single cell models for control and AF-remodelled conditions were incorporated into multicellular three-dimensional (3D) atrial tissue models. Effects of the AF-induced electrical remodelling were quantified as the changes of AP profile, AP duration (APD) and its dispersion across the atria, and the vulnerability of atrial tissue to the initiation of re-entry. The dynamic behaviour of re-entrant excitation waves in the 3D models was characterised. In our simulations, AF-induced electrical remodelling abbreviated atrial APD non-uniformly across the atria; this resulted in relatively short APDs co-existing with marked regional differences in the APD at junctions of the crista terminalis/pectinate muscle, pulmonary veins/left atrium. As a result, the measured tissue vulnerability to re-entry initiation at these tissue junctions was increased. The AF-induced electrical remodelling also stabilized and accelerated re-entrant excitation waves, leading to rapid and sustained re-entry. Under the AF-remodelled condition, re-entrant scroll waves in the 3D model degenerated into persistent and erratic wavelets, leading to fibrillation. In conclusion, realistic 3D atrial tissue models indicate that AF-induced electrical remodelling produces regionally heterogeneous and shortened APD; these respectively facilitate

  19. Autonomic mechanism for initiation of rapid firing from atria and pulmonary veins: evidence by ablation of ganglionated plexi

    PubMed Central

    Lu, Zhibing; Scherlag, Benjamin J.; Lin, Jiaxiong; Yu, Lilei; Guo, Ji-Hong; Niu, Guodong; Jackman, Warren M.; Lazzara, Ralph; Jiang, Hong; Po, Sunny S.

    2009-01-01

    Aims Previous studies showed that autonomic activation by high-frequency electrical stimulation (HFS) during myocardial refractoriness evokes rapid firing from pulmonary vein (PV) and atria, both in vitro and in vivo. This study sought to investigate the autonomic mechanism underlying the rapid firings at various sites by systematic ablation of multiple ganglionated plexi (GP). Methods and results In 43 mongrel dogs, rapid firing-mediated atrial fibrillation (AF) was induced by local HFS (200 Hz, impulse duration 0.1 ms, train duration 40 ms) to the PVs and atria during myocardial refractoriness. The main GP in the atrial fat pads or the ganglia along the ligament of Marshall (LOM) were then ablated. Ablation of the anterior right GP and inferior right GP significantly increased the AF threshold by HFS at the right atrium and PVs. The AF threshold at left atrium and PVs was significantly increased by ablation of the superior left GP and inferior left GP, and was further increased by ablation of the LOM. Ablation of left- or right-sided GP on the atria had a significant effect on contralateral PVs and atrium. Administration of esmolol (1 mg/kg) or atropine (1 mg) significantly increased AF threshold at all sites. Conclusion HFS applied to local atrial and PV sites initiated rapid firing via activation of the interactive autonomic network in the heart. GP in either left side or right side contributes to the rapid firings and AF originating from ipsolateral and contralateral PVs and atrium. Autonomic denervation suppresses or eliminates those rapid firings. PMID:19520703

  20. Optical Beat-Wave Experiment on CTIX

    NASA Astrophysics Data System (ADS)

    Horton, Robert; Hwang, David; Liu, Fei; Zhu, Ben; Evans, Russell

    2009-11-01

    By launching intense electromagnetic waves at differing frequencies, a wave at the beat (difference) frequency can be created within a region of plasma. The beat wave is efficiently damped, and electron current generated, if the beat frequency is close to local plasma frequency, and if phase velocity is close to electron thermal velocity. Beat-wave acceleration of plasma electrons was previously demonstrated at low plasma density [1]. At the higher densities of the CTIX compact-toroid accelerator, plasma frequencies are such that CO2 lasers (f 30 THz) are a cost-effective driver. An experiment is being prepared to test beat-wave current drive using two TEA CO2 lasers on CTIX. The experiment will test models of wave mixing, quasilinear modification of the velocity distribution, and amplification of seed current by plasma kinetic effects. An application of the methods developed may be standoff current generation in a target plasma. Experimental issues to be addressed include: precisely-timed production of the compressed, target plasma; grating tuning of the CO2 lasers for frequency selection; high-peak-power, simultaneous operation of TEA lasers, design of optics; optical and plasma diagnostics. Initial results will be presented.[4pt] [1] Rogers, J. H. and Hwang, D. Q., Phys. Rev. Lett. v68 p3877 (1992).

  1. Quantum Beats from Entangled Localized Surface Plasmons

    NASA Astrophysics Data System (ADS)

    Masiello, David

    Recent experiments report observations of quantum interference between plasmon resonances, inviting descriptions of plasmon-photon interaction using methods from quantum optics. Here we demonstrate, using a Heisenberg-Langevin approach, that the radiation emitted from the localized surface plasmon resonances of a mixed-metal heterodimer may exhibit observable, beat frequency interferences at a far-field detector, known as quantum beats. This prediction represents a correspondence between V-type atoms of quantum optics and the familiar heterodimer system of plasmonics. We explore this analogy in depth and find that although both systems support quantum beats, the heterodimer emits photons in bunches due to the bosonic nature of the plasmon. This highlights a significant difference between the properties of atomic and plasmonic systems. This work was supported by the National Science Foundation's CAREER program under Award Number CHE-1253775 and NSF XSEDE resources under Award Number PHY-130045.

  2. False beats in coupled piano string unisons

    NASA Astrophysics Data System (ADS)

    Capleton, Brian

    2004-02-01

    The behavior of a unison pair of piano strings coupled by the soundboard bridge, when one string has localized anisotropy in the reactive part of the bridge admittance for a given partial frequency, can be investigated using a theoretical matrix description. The anisotropy can cause what in piano tuning terminology is referred to as ``false beating'' in a partial of the single string. A mathematical model can be used to illustrate how ``mistunings'' between the strings of the unison (measured when the strings are sounding in isolation from each other) may theoretically arise as a consequence of the normal practice in piano tuning, of eliminating or reducing audible beating in the unison when both strings are sounding. ``False beats'' in a single string partial can be ``inherited'' by a partial of the coupled unison's spectrum, and mistunings between the strings can eliminate or reduce the appearance of this inheritance.

  3. Stark beats of Ar Rydberg states

    NASA Astrophysics Data System (ADS)

    Morioka, Y.; Aoto, T.; Yoshii, H.

    2001-11-01

    Vacuum ultraviolet fluorescence decay spectra of Ar atom resonance lines excited by pulsed vacuum ultraviolet light in a synchrotron single bunch operation were obtained under a static electric field. When an atom under the static electric field was excited simultaneously to both the magnetic sublevels M=0 and \\|M\\|=1 by polarized light and the observation area was asymmetric, Stark beats were observed in the fluorescent decay spectra. All observed beat frequencies varied proportionally to the square of the external electric field. The results for 8d and 9d doublet lines were compared with those obtained by the usual second order perturbation theory, assuming mixing ratios between three jl coupling scheme d-type states. The beat frequencies were also measured for other resonance lines.

  4. Energy Consumption of Actively Beating Flagella

    NASA Astrophysics Data System (ADS)

    Chen, Daniel; Nicastro, Daniela; Dogic, Zvonimir

    2012-02-01

    Motile cilia and flagella are important for propelling cells or driving fluid over tissues. The microtubule-based core in these organelles, the axoneme, has a nearly universal ``9+2'' arrangement of 9 outer doublet microtubules assembled around two singlet microtubules in the center. Thousands of molecular motor proteins are attached to the doublets and walk on neighboring outer doublets. The motors convert the chemical energy of ATP hydrolysis into sliding motion between adjacent doublet microtubules, resulting in precisely regulated oscillatory beating. Using demembranated sea urchin sperm flagella as an experimental platform, we simultaneously monitor the axoneme's consumption of ATP and its beating dynamics while key parameters, such as solution viscosity and ATP concentration, are varied. Insights into motor cooperativity during beating and energetic consequences of hydrodynamic interactions will be presented.

  5. False beats in coupled piano string unisons.

    PubMed

    Capleton, Brian

    2004-02-01

    The behavior of a unison pair of piano strings coupled by the soundboard bridge, when one string has localized anisotropy in the reactive part of the bridge admittance for a given partial frequency, can be investigated using a theoretical matrix description. The anisotropy can cause what in piano tuning terminology is referred to as "false beating" in a partial of the single string. A mathematical model can be used to illustrate how "mistunings" between the strings of the unison (measured when the strings are sounding in isolation from each other) may theoretically arise as a consequence of the normal practice in piano tuning, of eliminating or reducing audible beating in the unison when both strings are sounding. "False beats" in a single string partial can be "inherited" by a partial of the coupled unison's spectrum, and mistunings between the strings can eliminate or reduce the appearance of this inheritance. PMID:15000199

  6. Acoustical sensing of cardiomyocyte cluster beating

    SciTech Connect

    Tymchenko, Nina; Kunze, Angelika; Dahlenborg, Kerstin; Svedhem, Sofia; Steel, Daniella

    2013-06-14

    Highlights: •An example of the application of QCM-D to live cell studies. •Detection of human pluripotent stem cell-derived cardiomyocyte cluster beating. •Clusters were studied in a thin liquid film and in a large liquid volume. •The QCM-D beating profile provides an individual fingerprint of the hPS-CMCs. -- Abstract: Spontaneously beating human pluripotent stem cell-derived cardiomyocytes clusters (CMCs) represent an excellent in vitro tool for studies of human cardiomyocyte function and for pharmacological cardiac safety assessment. Such testing typically requires highly trained operators, precision plating, or large cell quantities, and there is a demand for real-time, label-free monitoring of small cell quantities, especially rare cells and tissue-like structures. Array formats based on sensing of electrical or optical properties of cells are being developed and in use by the pharmaceutical industry. A potential alternative to these techniques is represented by the quartz crystal microbalance with dissipation monitoring (QCM-D) technique, which is an acoustic surface sensitive technique that measures changes in mass and viscoelastic properties close to the sensor surface (from nm to μm). There is an increasing number of studies where QCM-D has successfully been applied to monitor properties of cells and cellular processes. In the present study, we show that spontaneous beating of CMCs on QCM-D sensors can be clearly detected, both in the frequency and the dissipation signals. Beating rates in the range of 66–168 bpm for CMCs were detected and confirmed by simultaneous light microscopy. The QCM-D beating profile was found to provide individual fingerprints of the hPS-CMCs. The presented results point towards acoustical assays for evaluation cardiotoxicity.

  7. Beta-adrenergic modulation of the release of atrial natriuretic factor from rat cardiac atria in vitro

    SciTech Connect

    Brown, A.; Imada, T.; Takayanagi, B.; Inagami, T.

    1986-03-01

    Several stimulatory factors for the release of atrial natriuretic factor, such as atrial stretch, atrial pacing and vasopressin, have been reported. We studied the effects of the adrenergic nervous system on the release of ANF using an in vitro perfusion system. Right and left atria from Sprague-Dawley rats were quartered and perfused with Krebs-Ringer bicarbonate solution gassed with 95% CO/sub 2//5% O/sub 2/ at 37/sup 0/C. Perfusate factions were collected every 2 minutes. Fractions were collected 20 minutes before and for 2 hours during the administration of test agents. ANF was measured by radioimmunoassay. Within 10 minutes of exposure to 10/sup -6/M isoproterenol, ANF secretion fell to less than 50% of its baseline level. However, beta agonists showed a stimulatory effect of 4-5 fold. Carbachol, in a concentration of 10/sup -2/M was used to demonstrate the viability of the atria exposed to isoproterenol, and produced a stimulation of ANF release of 4-6 times the basal level. The adrenergic nervous system can modulate ANF release in vitro. Further studies are being performed with selective beta agonists and antagonists to elucidate these results.

  8. Cardiovascular activity of 14-deoxy-11,12-didehydroandrographolide in the anaesthetised rat and isolated right atria.

    PubMed

    Zhang, C; Kuroyangi, M; Tan, B K

    1998-12-01

    The cardiovascular activity of 14-deoxy-11,12-didehydroandrographolide (DDA) from Andrographis paniculata (Burm.f.) Nees (Acanthaceae) was elucidated in anaesthetised Sprague-Dawley (SD) rats and isolated rat right atria. In anaesthetised rats, DDA produced significant falls in mean arterial blood pressure (MAP) and heart rate in a dose-dependent manner with the maximum decrease of 37.6 +/- 2.6% and 18.1 +/- 4.8%, respectively. The ED50 value for MAP was 3.43 mmol kg-1. Pharmacological antagonist studies were done using this dose. The hypotensive action of DDA was not mediated through effects on the alpha-adrenoceptor, muscarinic cholinergic and histaminergic receptors, for it was not affected by phentolamine, atropine as well as pyrilamine and cimetidine. However, it seems to work via adrenoceptors, autonomic ganglia receptor and angiotensin-converting enzyme, since the hypotensive effect of DDA was negated or attenuated in the presence of propranolol, hexamethonium and captopril. In the isolated right atria, DDA caused negative chronotropic action and antagonised isoproterenol-induced positive chronotropic actions in a non-competitive and dose-dependent manner. These results further supported the bradycardia-inducing and beta-adrenoceptor antagonistic properties of DDA in vivo. PMID:9990649

  9. "Keep the Beat": Healthy Blood Pressure Helps Prevent Heart Disease

    MedlinePlus

    ... Pressure "Keep the Beat": Healthy Blood Pressure Helps Prevent Heart Disease Past Issues / Winter 2010 Table of ... Articles "Keep the Beat": Healthy Blood Pressure Helps Prevent Heart Disease / Women and Heart Disease / Blood Pressure ...

  10. Beat the Instructor: An Introductory Forecasting Game

    ERIC Educational Resources Information Center

    Snider, Brent R.; Eliasson, Janice B.

    2013-01-01

    This teaching brief describes a 30-minute game where student groups compete in-class in an introductory time-series forecasting exercise. The students are challenged to "beat the instructor" who competes using forecasting techniques that will be subsequently taught. All forecasts are graphed prior to revealing the randomly generated…

  11. Terahertz radiation by beating Langmuir waves

    SciTech Connect

    Son, S.; Moon, Sung Joon; Park, J. Y.

    2012-11-15

    An intense terahertz (THz) radiation generated by the beating of two Langmuir waves, which are excited by the forward Raman scattering, is analyzed theoretically. The radiation energy per shot can be as high as 0.1 J, with the duration of 10 ps. Appropriate plasma density and the laser characteristics are examined.

  12. Acoustical sensing of cardiomyocyte cluster beating.

    PubMed

    Tymchenko, Nina; Kunze, Angelika; Dahlenborg, Kerstin; Svedhem, Sofia; Steel, Daniella

    2013-06-14

    Spontaneously beating human pluripotent stem cell-derived cardiomyocytes clusters (CMCs) represent an excellent in vitro tool for studies of human cardiomyocyte function and for pharmacological cardiac safety assessment. Such testing typically requires highly trained operators, precision plating, or large cell quantities, and there is a demand for real-time, label-free monitoring of small cell quantities, especially rare cells and tissue-like structures. Array formats based on sensing of electrical or optical properties of cells are being developed and in use by the pharmaceutical industry. A potential alternative to these techniques is represented by the quartz crystal microbalance with dissipation monitoring (QCM-D) technique, which is an acoustic surface sensitive technique that measures changes in mass and viscoelastic properties close to the sensor surface (from nm to μm). There is an increasing number of studies where QCM-D has successfully been applied to monitor properties of cells and cellular processes. In the present study, we show that spontaneous beating of CMCs on QCM-D sensors can be clearly detected, both in the frequency and the dissipation signals. Beating rates in the range of 66-168 bpm for CMCs were detected and confirmed by simultaneous light microscopy. The QCM-D beating profile was found to provide individual fingerprints of the hPS-CMCs. The presented results point towards acoustical assays for evaluation cardiotoxicity. PMID:23643814

  13. Mechanical communication in cardiac cell synchronized beating

    NASA Astrophysics Data System (ADS)

    Nitsan, Ido; Drori, Stavit; Lewis, Yair E.; Cohen, Shlomi; Tzlil, Shelly

    2016-05-01

    Cell-cell communication, which enables cells to coordinate their activity and is essential for growth, development and function, is usually ascribed a chemical or electrical origin. However, cells can exert forces and respond to environment elasticity and to mechanical deformations created by their neighbours. The extent to which this mechanosensing ability facilitates intercellular communication remains unclear. Here we demonstrate mechanical communication between cells directly for the first time, providing evidence for a long-range interaction that induces long-lasting alterations in interacting cells. We show that an isolated cardiac cell can be trained to beat at a given frequency by mechanically stimulating the underlying substrate. Deformations are induced using an oscillatory mechanical probe that mimics the deformations generated by a beating neighbouring cardiac cell. Unlike electrical field stimulation, the probe-induced beating rate is maintained by the cell for an hour after the stimulation stops, implying that long-term modifications occur within the cell. These long-term alterations provide a mechanism for cells that communicate mechanically to be less variable in their electromechanical delay. Mechanical coupling between cells therefore ensures that the final outcome of action potential pacing is synchronized beating. We further show that the contractile machinery is essential for mechanical communication.

  14. Heat Beats Cold for Treating Jellyfish Stings

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_158584.html Heat Beats Cold for Treating Jellyfish Stings Evidence favors hot water or hot packs to ease pain ... 29, 2016 (HealthDay News) -- If you're unlucky enough to suffer a jellyfish sting, new research says that heat is better than cold for easing the pain. ...

  15. Analyzing the Acoustic Beat with Mobile Devices

    ERIC Educational Resources Information Center

    Kuhn, Jochen; Vogt, Patrik; Hirth, Michael

    2014-01-01

    In this column, we have previously presented various examples of how physical relationships can be examined by analyzing acoustic signals using smartphones or tablet PCs. In this example, we will be exploring the acoustic phenomenon of small beats, which is produced by the overlapping of two tones with a low difference in frequency ?f. The…

  16. Beating Boredom, Creating Interest. Fastback 419.

    ERIC Educational Resources Information Center

    Russell, M. Thomas

    This "Fastback" focuses on avoiding boredom in schools. Following an introduction that explains the importance of teachers breathing life into subject matter, the booklet includes five sections. Section one, "The Nature of Boredom," defines boredom and explains that both teachers and students are responsible for beating boredom. Section two,…

  17. Renal nerves dynamically regulate renal blood flow in conscious, healthy rabbits.

    PubMed

    Schiller, Alicia M; Pellegrino, Peter R; Zucker, Irving H

    2016-01-15

    Despite significant clinical interest in renal denervation as a therapy, the role of the renal nerves in the physiological regulation of renal blood flow (RBF) remains debated. We hypothesized that the renal nerves physiologically regulate beat-to-beat RBF variability (RBFV). This was tested in chronically instrumented, healthy rabbits that underwent either bilateral surgical renal denervation (DDNx) or a sham denervation procedure (INV). Artifact-free segments of RBF and arterial pressure (AP) from calmly resting, conscious rabbits were used to extract RBFV and AP variability for time-domain, frequency-domain, and nonlinear analysis. Whereas steady-state measures of RBF, AP, and heart rate did not statistically differ between groups, DDNx rabbits had greater RBFV than INV rabbits. AP-RBF transfer function analysis showed greater admittance gain in DDNx rabbits than in INV rabbits, particularly in the low-frequency (LF) range where systemic sympathetic vasomotion gives rise to AP oscillations. In the LF range, INV rabbits exhibited a negative AP-RBF phase shift and low coherence, consistent with the presence of an active control system. Neither of these features were present in the LF range of DDNx rabbits, which showed no phase shift and high coherence, consistent with a passive, Ohm's law pressure-flow relationship. Renal denervation did not significantly affect nonlinear RBFV measures of chaos, self-affinity, or complexity, nor did it significantly affect glomerular filtration rate or extracellular fluid volume. Cumulatively, these data suggest that the renal nerves mediate LF renal sympathetic vasomotion, which buffers RBF from LF AP oscillations in conscious, healthy rabbits. PMID:26538235

  18. Cysticercosis in laboratory rabbits.

    PubMed

    Owiny, J R

    2001-03-01

    There are no data on the current incidence of Taenia pisiformis in laboratory rabbits. Two cases of cysticercosis most likely due to T. pisiformis in laboratory rabbits (intermediate host) are presented. Both rabbits had no contact with dogs (final host); their caretakers did not work with dogs, and these caretakers changed into facility scrubs and wore gloves when working with the rabbits. Rabbit 1 may have been infected after being fed hay at our facility. In light of the life cycle of the parasite and the history of rabbit 2, it potentially could have been infected prior to arrival at our facility. There have been only three cases of tapeworm cysts in rabbits in our facility (average daily census, 250) during the last 10 years (incidence, < 1%). This report indicates that although cysticercosis is rare in laboratory rabbits, one should always be aware of such incidental findings. Although it may not produce overt illness in the rabbit, hepatic migration could adversely affect the outcome of some experimental procedures PMID:11300689

  19. Model for the heart beat-to-beat time series during meditation

    NASA Astrophysics Data System (ADS)

    Capurro, A.; Diambra, L.; Malta, C. P.

    2003-09-01

    We present a model for the respiratory modulation of the heart beat-to-beat interval series. The model consists of a pacemaker, that simulates the membrane potential of the sinoatrial node, modulated by a periodic input signal plus correlated noise that simulates the respiratory input. The model was used to assess the waveshape of the respiratory signals needed to reproduce in the phase space the trajectory of experimental heart beat-to-beat interval data. The data sets were recorded during meditation practices of the Chi and Kundalini Yoga techniques. Our study indicates that in the first case the respiratory signal has the shape of a smoothed square wave, and in the second case it has the shape of a smoothed triangular wave.

  20. Beat Gestures Modulate Auditory Integration in Speech Perception

    ERIC Educational Resources Information Center

    Biau, Emmanuel; Soto-Faraco, Salvador

    2013-01-01

    Spontaneous beat gestures are an integral part of the paralinguistic context during face-to-face conversations. Here we investigated the time course of beat-speech integration in speech perception by measuring ERPs evoked by words pronounced with or without an accompanying beat gesture, while participants watched a spoken discourse. Words…

  1. Finger beat-to-beat blood pressure responses to successive hand elevations.

    PubMed

    Raamat, R; Jagomägi, K; Talts, J; Mäger, I

    2009-06-01

    We investigated finger beat-to-beat blood pressure responses to a series of successive hand elevations in 14 normal volunteers. By passive elevation of the hand by 40 cm and lowering it again after a minute, calibrated hydrostatic pressure changes were induced in the finger arteries of the subjects. Three successive procedures with a 2-min interval between them were performed. Transitions between positions were completed smoothly over a 10-s period. Non-invasive beat-to-beat mean arterial pressure (MAP) in the finger arteries was measured by applying the servo-oscillometric physiograph (University of Tartu, Estonia). A good agreement between the evoked MAP changes during all the three hand elevations (-31.2, -30.4 and -30.0 mmHg, respectively) and the calculated hydrostatic pressure change (-31.0 mmHg) was obtained. The height difference of approximately 40 cm and rate of 4-5 cm/s can be recommended for the hand elevation test, greater postural changes and higher rates may diminish agreement between the measured blood pressure response and the corresponding hydrostatic pressure change. The applied hydrostatic test may be helpful for assessing the accuracy of beat-to-beat finger blood pressure measurement. PMID:19027338

  2. Detrended fluctuation analysis of non-stationary cardiac beat-to-beat interval of sick infants

    NASA Astrophysics Data System (ADS)

    Govindan, Rathinaswamy B.; Massaro, An N.; Al-Shargabi, Tareq; Niforatos Andescavage, Nickie; Chang, Taeun; Glass, Penny; du Plessis, Adre J.

    2014-11-01

    We performed detrended fluctuation analysis (DFA) of cardiac beat-to-beat intervals (RRis) collected from sick newborn infants over 1-4 day periods. We calculated four different metrics from the DFA fluctuation function: the DFA exponents αL (>40 beats up to one-fourth of the record length), αs (15-30 beats), root-mean-square (RMS) fluctuation on a short-time scale (20-50 beats), and RMS fluctuation on a long-time scale (110-150 beats). Except αL , all metrics clearly distinguished two groups of newborn infants (favourable vs. adverse) with well-characterized outcomes. However, the RMS fluctuations distinguished the two groups more consistently over time compared to αS . Furthermore, RMS distinguished the RRi of the two groups earlier compared to the DFA exponent. In all the three measures, the favourable outcome group displayed higher values, indicating a higher magnitude of (auto-)correlation and variability, thus normal physiology, compared to the adverse outcome group.

  3. 3D absolute shape measurement of live rabbit hearts with a superfast two-frequency phase-shifting technique.

    PubMed

    Wang, Yajun; Laughner, Jacob I; Efimov, Igor R; Zhang, Song

    2013-03-11

    This paper presents a two-frequency binary phase-shifting technique to measure three-dimensional (3D) absolute shape of beating rabbit hearts. Due to the low contrast of the cardiac surface, the projector and the camera must remain focused, which poses challenges for any existing binary method where the measurement accuracy is low. To conquer this challenge, this paper proposes to utilize the optimal pulse width modulation (OPWM) technique to generate high-frequency fringe patterns, and the error-diffusion dithering technique to produce low-frequency fringe patterns. Furthermore, this paper will show that fringe patterns produced with blue light provide the best quality measurements compared to fringe patterns generated with red or green light; and the minimum data acquisition speed for high quality measurements is around 800 Hz for a rabbit heart beating at 180 beats per minute. PMID:23482151

  4. Metal flowing of involute spline cold roll-beating forming

    NASA Astrophysics Data System (ADS)

    Cui, Fengkui; Wang, Xiaoqiang; Zhang, Fengshou; Xu, Hongyu; Quan, Jianhui; Li, Yan

    2013-09-01

    The present research on involute spline cold roll-beating forming is mainly about the principles and motion relations of cold roll-beating, the theory of roller design, and the stress and strain field analysis of cold roll-beating, etc. However, the research on law of metal flow in the forming process of involute spline cold roll-beating is rare. According to the principle of involute spline cold roll-beating, the contact model between the rollers and the spline shaft blank in the process of cold roll-beating forming is established, and the theoretical analysis of metal flow in the cold roll-beating deforming region is proceeded. A finite element model of the spline cold roll-beating process is established, the formation mechanism of the involute spline tooth profile in cold roll-beating forming process is studied, and the node flow tracks of the deformation area are analyzed. The experimental research on the metal flow of cold roll-beating spline is conducted, and the metallographic structure variation, grain characteristics and metal flow line of the different tooth profile area are analyzed. The experimental results show that the particle flow directions of the deformable bodies in cold roll-beating deformation area are determined by the minimum moving resistance. There are five types of metal flow rules of the deforming region in the process of cold roll-beating forming. The characteristics of involute spline cold roll-beating forming are given, and the forming mechanism of involute spline cold roll-beating is revealed. This paper researches the law of metal flow in the forming process of involute spline cold roll-beating, which provides theoretical supports for solving the tooth profile forming quality problem.

  5. Impairment of beat-based rhythm discrimination in Parkinson's disease.

    PubMed

    Grahn, Jessica A; Brett, Matthew

    2009-01-01

    Humans often synchronize movements to the beat, indicating that motor areas may be involved in detecting or generating a beat. The basal ganglia have been shown to be preferentially activated by perception of rhythms with a regular beat (Grahn and Brett, 2007), but their necessity for beat-based rhythm processing has not been proven. Previous research has shown that Parkinson's disease (PD) patients are impaired in timing of isochronous intervals (Harrington et al., 1998a; O'Boyle et al., 1996), but little work has tested more complex rhythms. In healthy volunteers, behavioural performance is better for rhythms with a beat than without a beat (Essens, 1986). We tested PD patients and controls on a rhythm discrimination task to determine if basal ganglia dysfunction results in an impairment of processing rhythms that have a beat. Unlike rhythm reproduction, discrimination has no motor requirements that are problematic for patients. Half the rhythms had a beat-based structure, and half did not. Subjects heard a rhythm twice and then indicated if a third presentation of the rhythm was the same or different. We predicted that PD patients would benefit less from beat structure than controls, resulting in a group by rhythm-type interaction, with reduced relative performance for the beat-based sequences in the PD group. Indeed this was the pattern of the results. In the control group, a significant advantage was observed for discrimination of rhythms with a beat compared to those without a beat. This advantage was greatly reduced in the PD group. Discrimination of beat-based rhythms was significantly impaired in PD patients compared to controls, whereas discrimination of non-beat-based rhythms did not differ significantly. This suggests that the basal ganglia are part of a system involved in detecting or generating an internal beat, and that this system is compromised in patients with Parkinson's disease. PMID:19027895

  6. Astroviruses in Rabbits

    PubMed Central

    Moschidou, Paschalina; Pinto, Pierfrancesco; Catella, Cristiana; Desario, Constantina; Larocca, Vittorio; Circella, Elena; Bànyai, Krisztian; Lavazza, Antonio; Magistrali, Chiara; Decaro, Nicola; Buonavoglia, Canio

    2011-01-01

    By screening rabbits with enterocolitis or enteritis complex and asymptomatic rabbits, we identified a novel astrovirus. The virus was distantly related (19.3%–23.7% aa identity) in the capsid precursor to other mammalian astroviruses within the Mamastrovirus genus. By using real-time reverse transcription PCR, with specific primers and probes and targeting a conserved stretch in open reading frame 1b, we found rabbit astrovirus in 10 (43%) of 23 samples from animals with enteric disease and in 25 (18%) of 139 samples from asymptomatic animals in Italy during 2005–2008. The mean and median titers in the positive animals were 102× and 103× greater, respectively, in the symptomatic animals than in the asymptomatic animals. These findings support the idea that rabbit astroviruses should be included in the diagnostic algorithm of rabbit enteric disease and animal experiments to increase information obtained about their epidemiology and potential pathogenic role. PMID:22172457

  7. Beat-to-beat cycle length variability of spontaneously beating guinea pig sinoatrial cells: relative contributions of the membrane and calcium clocks.

    PubMed

    Zaniboni, Massimiliano; Cacciani, Francesca; Lux, Robert L

    2014-01-01

    The heartbeat arises rhythmically in the sino-atrial node (SAN) and then spreads regularly throughout the heart. The molecular mechanism underlying SAN rhythm has been attributed by recent studies to the interplay between two clocks, one involving the hyperpolarization activated cation current If (the membrane clock), and the second attributable to activation of the electrogenic NaCa exchanger by spontaneous sarcoplasmic releases of calcium (the calcium clock). Both mechanisms contain, in principle, sources of beat-to-beat cycle length variability, which can determine the intrinsic variability of SAN firing and, in turn, contribute to the heart rate variability. In this work we have recorded long sequences of action potentials from patch clamped guinea pig SAN cells (SANCs) perfused, in turn, with normal Tyrode solution, with the If inhibitor ivabradine (3 µM), then back to normal Tyrode, and again with the ryanodine channels inhibitor ryanodine (3 µM). We have found that, together with the expected increase in beating cycle length (+25%), the application of ivabradine brought about a significant and dramatic increase in beat-to-beat cycle length variability (+50%). Despite the similar effect on firing rate, ryanodine did not modify significantly beat-to-beat cycle length variability. Acetylcholine was also applied and led to a 131% increase of beating cycle length, with only a 70% increase in beat-to-beat cycle length variability. We conclude that the main source of inter-beat variability of SANCs firing rate is related to the mechanism of the calcium clock, whereas the membrane clock seems to act in stabilizing rate. Accordingly, when the membrane clock is silenced by application of ivabradine, stochastic variations of the calcium clock are free to make SANCs beating rhythm more variable. PMID:24940609

  8. Beat-to-Beat Cycle Length Variability of Spontaneously Beating Guinea Pig Sinoatrial Cells: Relative Contributions of the Membrane and Calcium Clocks

    PubMed Central

    Zaniboni, Massimiliano; Cacciani, Francesca; Lux, Robert L.

    2014-01-01

    The heartbeat arises rhythmically in the sino-atrial node (SAN) and then spreads regularly throughout the heart. The molecular mechanism underlying SAN rhythm has been attributed by recent studies to the interplay between two clocks, one involving the hyperpolarization activated cation current If (the membrane clock), and the second attributable to activation of the electrogenic NaCa exchanger by spontaneous sarcoplasmic releases of calcium (the calcium clock). Both mechanisms contain, in principle, sources of beat-to-beat cycle length variability, which can determine the intrinsic variability of SAN firing and, in turn, contribute to the heart rate variability. In this work we have recorded long sequences of action potentials from patch clamped guinea pig SAN cells (SANCs) perfused, in turn, with normal Tyrode solution, with the If inhibitor ivabradine (3 µM), then back to normal Tyrode, and again with the ryanodine channels inhibitor ryanodine (3 µM). We have found that, together with the expected increase in beating cycle length (+25%), the application of ivabradine brought about a significant and dramatic increase in beat-to-beat cycle length variability (+50%). Despite the similar effect on firing rate, ryanodine did not modify significantly beat-to-beat cycle length variability. Acetylcholine was also applied and led to a 131% increase of beating cycle length, with only a 70% increase in beat-to-beat cycle length variability. We conclude that the main source of inter-beat variability of SANCs firing rate is related to the mechanism of the calcium clock, whereas the membrane clock seems to act in stabilizing rate. Accordingly, when the membrane clock is silenced by application of ivabradine, stochastic variations of the calcium clock are free to make SANCs beating rhythm more variable. PMID:24940609

  9. Eps15 Homology Domain-containing Protein 3 Regulates Cardiac T-type Ca2+ Channel Targeting and Function in the Atria.

    PubMed

    Curran, Jerry; Musa, Hassan; Kline, Crystal F; Makara, Michael A; Little, Sean C; Higgins, John D; Hund, Thomas J; Band, Hamid; Mohler, Peter J

    2015-05-01

    Proper trafficking of membrane-bound ion channels and transporters is requisite for normal cardiac function. Endosome-based protein trafficking of membrane-bound ion channels and transporters in the heart is poorly understood, particularly in vivo. In fact, for select cardiac cell types such as atrial myocytes, virtually nothing is known regarding endosomal transport. We previously linked the C-terminal Eps15 homology domain-containing protein 3 (EHD3) with endosome-based protein trafficking in ventricular cardiomyocytes. Here we sought to define the roles and membrane protein targets for EHD3 in atria. We identify the voltage-gated T-type Ca(2+) channels (CaV3.1, CaV3.2) as substrates for EHD3-dependent trafficking in atria. Mice selectively lacking EHD3 in heart display reduced expression and targeting of both Cav3.1 and CaV3.2 in the atria. Furthermore, functional experiments identify a significant loss of T-type-mediated Ca(2+) current in EHD3-deficient atrial myocytes. Moreover, EHD3 associates with both CaV3.1 and CaV3.2 in co-immunoprecipitation experiments. T-type Ca(2+) channel function is critical for proper electrical conduction through the atria. Consistent with these roles, EHD3-deficient mice demonstrate heart rate variability, sinus pause, and atrioventricular conduction block. In summary, our findings identify CaV3.1 and CaV3.2 as substrates for EHD3-dependent protein trafficking in heart, provide in vivo data on endosome-based trafficking pathways in atria, and implicate EHD3 as a key player in the regulation of atrial myocyte excitability and cardiac conduction. PMID:25825486

  10. Eps15 Homology Domain-containing Protein 3 Regulates Cardiac T-type Ca2+ Channel Targeting and Function in the Atria*

    PubMed Central

    Curran, Jerry; Musa, Hassan; Kline, Crystal F.; Makara, Michael A.; Little, Sean C.; Higgins, John D.; Hund, Thomas J.; Band, Hamid; Mohler, Peter J.

    2015-01-01

    Proper trafficking of membrane-bound ion channels and transporters is requisite for normal cardiac function. Endosome-based protein trafficking of membrane-bound ion channels and transporters in the heart is poorly understood, particularly in vivo. In fact, for select cardiac cell types such as atrial myocytes, virtually nothing is known regarding endosomal transport. We previously linked the C-terminal Eps15 homology domain-containing protein 3 (EHD3) with endosome-based protein trafficking in ventricular cardiomyocytes. Here we sought to define the roles and membrane protein targets for EHD3 in atria. We identify the voltage-gated T-type Ca2+ channels (CaV3.1, CaV3.2) as substrates for EHD3-dependent trafficking in atria. Mice selectively lacking EHD3 in heart display reduced expression and targeting of both Cav3.1 and CaV3.2 in the atria. Furthermore, functional experiments identify a significant loss of T-type-mediated Ca2+ current in EHD3-deficient atrial myocytes. Moreover, EHD3 associates with both CaV3.1 and CaV3.2 in co-immunoprecipitation experiments. T-type Ca2+ channel function is critical for proper electrical conduction through the atria. Consistent with these roles, EHD3-deficient mice demonstrate heart rate variability, sinus pause, and atrioventricular conduction block. In summary, our findings identify CaV3.1 and CaV3.2 as substrates for EHD3-dependent protein trafficking in heart, provide in vivo data on endosome-based trafficking pathways in atria, and implicate EHD3 as a key player in the regulation of atrial myocyte excitability and cardiac conduction. PMID:25825486

  11. Beat that Word: How Listeners Integrate Beat Gesture and Focus in Multimodal Speech Discourse.

    PubMed

    Dimitrova, Diana; Chu, Mingyuan; Wang, Lin; Özyürek, Asli; Hagoort, Peter

    2016-09-01

    Communication is facilitated when listeners allocate their attention to important information (focus) in the message, a process called "information structure." Linguistic cues like the preceding context and pitch accent help listeners to identify focused information. In multimodal communication, relevant information can be emphasized by nonverbal cues like beat gestures, which represent rhythmic nonmeaningful hand movements. Recent studies have found that linguistic and nonverbal attention cues are integrated independently in single sentences. However, it is possible that these two cues interact when information is embedded in context, because context allows listeners to predict what information is important. In an ERP study, we tested this hypothesis and asked listeners to view videos capturing a dialogue. In the critical sentence, focused and nonfocused words were accompanied by beat gestures, grooming hand movements, or no gestures. ERP results showed that focused words are processed more attentively than nonfocused words as reflected in an N1 and P300 component. Hand movements also captured attention and elicited a P300 component. Importantly, beat gesture and focus interacted in a late time window of 600-900 msec relative to target word onset, giving rise to a late positivity when nonfocused words were accompanied by beat gestures. Our results show that listeners integrate beat gesture with the focus of the message and that integration costs arise when beat gesture falls on nonfocused information. This suggests that beat gestures fulfill a unique focusing function in multimodal discourse processing and that they have to be integrated with the information structure of the message. PMID:27027421

  12. Dispersion of refractoriness in patients with paroxysmal atrial fibrillation. Evaluation with simultaneous endocardial recordings from both atria.

    PubMed

    Li, Zhen; Hertervig, Eva; Carlson, Jonas; Johansson, Camilla; Olsson, S Bertil; Yuan, Shiwen

    2002-07-01

    This article studies the role of dispersion of atrial refractoriness (DAR) in the genesis of atrial fibrillation (AF). A 20-polar Halo catheter or a 40-polar basket catheter was placed in the right atrium and a 10-polar catheter in the coronary sinus in 21 patients with paroxysmal AF. Bipolar electrograms during AF were recorded from 7 to 16 sites in both atria. As control, electrograms during AF induced by extra-stimulation or burst pacing were also recorded from 4 to 14 sites in both atria in 12 patients with supraventricular tachycardias but without history of AF. The local atrial fibrillation intervals (AFI) during a period of 10 s or 20 s were measured and the mean, median and the 5th, 10th and 15th percentile AFIs at each site were calculated as estimates of the local effective refractory period (AERP). The maximum dispersion and variance of the estimated AERP among the 7-16/4-14 sites were used as measures of the DAR. The maximum dispersion and variance of the 5th and 10th percentile AFIs were significantly greater in the AF group than those in the control group, which were mainly due to the shortening of the minimum 5th and 10th percentile AFIs. No significant differences in dispersion and variance of the mean and median AFIs were shown between the 2 groups. The dispersion and variance of atrial refractoriness during AF estimated from the measurement of short AFIs were significantly greater in patients with paroxysmal AF than in those without clinical AF. The increased dispersion of refractoriness in patients with AF was mainly due to the shortening of the minimum AFIs. These findings suggest the involvement of an increased dispersion of atrial refractoriness in the genesis of paroxysmal AF. PMID:12122613

  13. Newborn infants detect the beat in music.

    PubMed

    Winkler, István; Háden, Gábor P; Ladinig, Olivia; Sziller, István; Honing, Henkjan

    2009-02-17

    To shed light on how humans can learn to understand music, we need to discover what the perceptual capabilities with which infants are born. Beat induction, the detection of a regular pulse in an auditory signal, is considered a fundamental human trait that, arguably, played a decisive role in the origin of music. Theorists are divided on the issue whether this ability is innate or learned. We show that newborn infants develop expectation for the onset of rhythmic cycles (the downbeat), even when it is not marked by stress or other distinguishing spectral features. Omitting the downbeat elicits brain activity associated with violating sensory expectations. Thus, our results strongly support the view that beat perception is innate. PMID:19171894

  14. Stochastic ion acceleration by beating electrostatic waves.

    PubMed

    Jorns, B; Choueiri, E Y

    2013-01-01

    A study is presented of the stochasticity in the orbit of a single, magnetized ion produced by the particle's interaction with two beating electrostatic waves whose frequencies differ by the ion cyclotron frequency. A second-order Lie transform perturbation theory is employed in conjunction with a numerical analysis of the maximum Lyapunov exponent to determine the velocity conditions under which stochasticity occurs in this dynamical system. Upper and lower bounds in ion velocity are found for stochastic orbits with the lower bound approximately equal to the phase velocity of the slower wave. A threshold condition for the onset of stochasticity that is linear with respect to the wave amplitudes is also derived. It is shown that the onset of stochasticity occurs for beating electrostatic waves at lower total wave energy densities than for the case of a single electrostatic wave or two nonbeating electrostatic waves. PMID:23410446

  15. Modeling of Nonlinear Beat Signals of TAE's

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Berk, Herbert; Breizman, Boris; Zheng, Linjin

    2012-03-01

    Experiments on Alcator C-Mod reveal Toroidal Alfven Eigenmodes (TAE) together with signals at various beat frequencies, including those at twice the mode frequency. The beat frequencies are sidebands driven by quadratic nonlinear terms in the MHD equations. These nonlinear sidebands have not yet been quantified by any existing codes. We extend the AEGIS code to capture nonlinear effects by treating the nonlinear terms as a driving source in the linear MHD solver. Our goal is to compute the spatial structure of the sidebands for realistic geometry and q-profile, which can be directly compared with experiment in order to interpret the phase contrast imaging diagnostic measurements and to enable the quantitative determination of the Alfven wave amplitude in the plasma core

  16. Newborn infants detect the beat in music

    PubMed Central

    Winkler, István; Háden, Gábor P.; Ladinig, Olivia; Sziller, István; Honing, Henkjan

    2009-01-01

    To shed light on how humans can learn to understand music, we need to discover what the perceptual capabilities with which infants are born. Beat induction, the detection of a regular pulse in an auditory signal, is considered a fundamental human trait that, arguably, played a decisive role in the origin of music. Theorists are divided on the issue whether this ability is innate or learned. We show that newborn infants develop expectation for the onset of rhythmic cycles (the downbeat), even when it is not marked by stress or other distinguishing spectral features. Omitting the downbeat elicits brain activity associated with violating sensory expectations. Thus, our results strongly support the view that beat perception is innate. PMID:19171894

  17. Beat frequency interference pattern characteristics study

    NASA Technical Reports Server (NTRS)

    Ott, J. H.; Rice, J. S.

    1981-01-01

    The frequency spectra and corresponding beat frequencies created by the relative motions between multiple Solar Power Satellites due to solar wind, lunar gravity, etc. were analyzed. The results were derived mathematically and verified through computer simulation. Frequency spectra plots were computer generated. Detailed computations were made for the seven following locations in the continental US: Houston, Tx.; Seattle, Wa.; Miami, Fl.; Chicago, Il.; New York, NY; Los Angeles, Ca.; and Barberton, Oh.

  18. Hepatitis E Virus in Farmed Rabbits, Wild Rabbits and Petting Farm Rabbits in the Netherlands.

    PubMed

    Burt, Sara A; Veltman, Jorg; Hakze-van der Honing, Renate; Schmitt, Heike; van der Poel, Wim H M

    2016-09-01

    Rabbits have been suggested as a zoonotic source of Hepatitis E virus. Phylogenetic analysis of HEV isolates from farmed, wild and pet rabbits in the Netherlands (23, 0, and 60 % respectively) showed them to be grouped amongst published rabbit HEV sequences and distinct from most human isolates. Dutch rabbits are unlikely to be a zoonotic source. PMID:27147250

  19. Beat-to-beat heart rate estimation fusing multimodal video and sensor data

    PubMed Central

    Antink, Christoph Hoog; Gao, Hanno; Brüser, Christoph; Leonhardt, Steffen

    2015-01-01

    Coverage and accuracy of unobtrusively measured biosignals are generally relatively low compared to clinical modalities. This can be improved by exploiting redundancies in multiple channels with methods of sensor fusion. In this paper, we demonstrate that two modalities, skin color variation and head motion, can be extracted from the video stream recorded with a webcam. Using a Bayesian approach, these signals are fused with a ballistocardiographic signal obtained from the seat of a chair with a mean absolute beat-to-beat estimation error below 25 milliseconds and an average coverage above 90% compared to an ECG reference. PMID:26309754

  20. Beat-to-beat heart rate estimation fusing multimodal video and sensor data.

    PubMed

    Antink, Christoph Hoog; Gao, Hanno; Brüser, Christoph; Leonhardt, Steffen

    2015-08-01

    Coverage and accuracy of unobtrusively measured biosignals are generally relatively low compared to clinical modalities. This can be improved by exploiting redundancies in multiple channels with methods of sensor fusion. In this paper, we demonstrate that two modalities, skin color variation and head motion, can be extracted from the video stream recorded with a webcam. Using a Bayesian approach, these signals are fused with a ballistocardiographic signal obtained from the seat of a chair with a mean absolute beat-to-beat estimation error below 25 milliseconds and an average coverage above 90% compared to an ECG reference. PMID:26309754

  1. Oil well rabbit

    SciTech Connect

    Yerian, H.W.

    1983-10-18

    A well rabbit is described which has a high gas seal capacity as well as resistance to wear and structural failure. The rabbit comprises a one-piece elongated generally cylindrical body having external circumferential gas-sealing grooves spaced along its length and a set of helically oriented slots at its lower end. The circumferential grooves, which work collectively in the manner of a labyrinth seal, are undercut in a way to deflect escaping gas streams and promote turbulence to enhance their gas-sealing capability. The undercut profile and relative spacing of the grooves leaves a large surface area between the grooves for distributing radial forces and thereby decreasing the wear rate of the rabbit. The helically oriented slots convert energy of upward escaping gas into rotational energy in the rabbit. (3 claims.

  2. The Harvard Beat Assessment Test (H-BAT): a battery for assessing beat perception and production and their dissociation

    PubMed Central

    Fujii, Shinya; Schlaug, Gottfried

    2013-01-01

    Humans have the abilities to perceive, produce, and synchronize with a musical beat, yet there are widespread individual differences. To investigate these abilities and to determine if a dissociation between beat perception and production exists, we developed the Harvard Beat Assessment Test (H-BAT), a new battery that assesses beat perception and production abilities. H-BAT consists of four subtests: (1) music tapping test (MTT), (2) beat saliency test (BST), (3) beat interval test (BIT), and (4) beat finding and interval test (BFIT). MTT measures the degree of tapping synchronization with the beat of music, whereas BST, BIT, and BFIT measure perception and production thresholds via psychophysical adaptive stair-case methods. We administered the H-BAT on thirty individuals and investigated the performance distribution across these individuals in each subtest. There was a wide distribution in individual abilities to tap in synchrony with the beat of music during the MTT. The degree of synchronization consistency was negatively correlated with thresholds in the BST, BIT, and BFIT: a lower degree of synchronization was associated with higher perception and production thresholds. H-BAT can be a useful tool in determining an individual's ability to perceive and produce a beat within a single session. PMID:24324421

  3. The Harvard Beat Assessment Test (H-BAT): a battery for assessing beat perception and production and their dissociation.

    PubMed

    Fujii, Shinya; Schlaug, Gottfried

    2013-01-01

    Humans have the abilities to perceive, produce, and synchronize with a musical beat, yet there are widespread individual differences. To investigate these abilities and to determine if a dissociation between beat perception and production exists, we developed the Harvard Beat Assessment Test (H-BAT), a new battery that assesses beat perception and production abilities. H-BAT consists of four subtests: (1) music tapping test (MTT), (2) beat saliency test (BST), (3) beat interval test (BIT), and (4) beat finding and interval test (BFIT). MTT measures the degree of tapping synchronization with the beat of music, whereas BST, BIT, and BFIT measure perception and production thresholds via psychophysical adaptive stair-case methods. We administered the H-BAT on thirty individuals and investigated the performance distribution across these individuals in each subtest. There was a wide distribution in individual abilities to tap in synchrony with the beat of music during the MTT. The degree of synchronization consistency was negatively correlated with thresholds in the BST, BIT, and BFIT: a lower degree of synchronization was associated with higher perception and production thresholds. H-BAT can be a useful tool in determining an individual's ability to perceive and produce a beat within a single session. PMID:24324421

  4. Novel bocaparvoviruses in rabbits.

    PubMed

    Lanave, G; Martella, V; Farkas, S L; Marton, S; Fehér, E; Bodnar, L; Lavazza, A; Decaro, N; Buonavoglia, C; Bányai, K

    2015-11-01

    Bocaparvovirus is a newly established genus within the family Parvoviridae and has been identified as a possible cause of enteric, respiratory, reproductive/neonatal and neurological disease in humans and several animal species. In this study, metagenomic analysis was used to identify and characterise a novel bocaparvovirus in the faeces of rabbits with enteric disease. To assess the prevalence of the novel virus, rectal swabs and faecal samples obtained from rabbits with and without diarrhoea were screened with a specific PCR assay. The complete genome sequence of the novel parvovirus was reconstructed. The virus was distantly related to other bocaparvoviruses; the three ORFs shared 53%, 53% and 50% nucleotide identity, respectively, to homologous genes of porcine bocaparvoviruses. The virus was detected in 8/29 (28%) and 16/95 (17%) samples of rabbits with and without diarrhoea, respectively. Sequencing of the capsid protein fragment targeted by the diagnostic PCR identified two distinct bocaparvovirus populations/sub-types, with 91.7-94.5% nucleotide identity to each other. Including these novel parvoviruses in diagnostic algorithms of rabbit diseases might help inform their potential pathogenic role and impact on rabbit production and the virological profiles of laboratory rabbits. PMID:26383859

  5. Attosecond quantum-beat spectroscopy in helium

    NASA Astrophysics Data System (ADS)

    Shivaram, Niranjan; Tong, Xiao-Min; Timmers, Henry; Sandhu, Arvinder

    2016-03-01

    The evolution of electron wavepackets determines the course of many physical and chemical phenomena, and attosecond spectroscopy aims to measure and control such dynamics in real time. Here, we investigate radial electron wavepacket motion in helium by using an XUV attosecond pulse train to prepare a coherent superposition of excited states and a delayed femtosecond IR pulse to ionize them. Quantum-beat signals observed in the high resolution photoelectron spectrogram allow us to follow the field-free evolution of the bound electron wavepacket and determine the time-dependent ionization dynamics of the low-lying 2{{p}} state.

  6. Beating the forger: authenticating ceramic antiquities

    NASA Astrophysics Data System (ADS)

    Stoneham, Doreen; Stoneham, Marshall

    2010-09-01

    Today's forger may have skills to match the artists and craftsmen of the past. But can they be exposed by scientific methods? Ceramic antiquities - including pottery, porcelains, and bronzes with a casting core - have long been valued, and demonstrable antiquity is crucial. Thermoluminescence provides key evidence as to when the object was fired. We describe the basic ideas, the methods themselves, and some of the potential limitations. Examples illustrate the remarkable ingenuity of forgers, who are making determined efforts to beat the physics-based tests of authenticity.

  7. Viral diseases of the rabbit.

    PubMed

    Krogstad, Aric P; Simpson, Janet E; Korte, Scott W

    2005-01-01

    Viral disease in the rabbit is encountered infrequently by the clinical practitioner; however, several viral diseases were reported to occur in this species. Viral diseases that are described in the rabbit primarily may affect the integument, gastrointestinal tract or, central nervous system or maybe multi-systemic in nature. Rabbit viral diseases range from oral papillomatosis, with benign clinical signs, to rabbit hemorrhagic disease and myxomatosis, which may result in significant clinical disease and mortality. The wild rabbit may serve as a reservoir for disease transmission for many of these viral agents. In general, treatment of viral disease in the rabbit is supportive in nature. PMID:15585192

  8. Pulmonary artery banding alters the expression of Ca2+ transport proteins in the right atrium in rabbits.

    PubMed

    Gupta, Subash C; Varian, Kenneth D; Bal, Naresh C; Abraham, Jessica L; Periasamy, Muthu; Janssen, Paul M L

    2009-06-01

    Following pulmonary artery banding (PAB), the contractile function of right ventricle diminishes over time. Subsequently, the right atrium (RA) has to contract against a higher afterload, but it is unknown to what extent ventricular dysfunction has an effect on the atrial contractility. We hypothesized that right ventricular pressure overload may have an affect on atrial contractility and Ca(2+) transport protein expression. Therefore, we induced pressure overload of the right ventricle by PAB for 10 wk in rabbits and examined the changes in the expression of Ca(2+) transport proteins in the atrium. We demonstrate that PAB significantly decreased the expression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (Serca) 2a while expression of Na(+)/Ca(2+) exchanger-1 was significantly upregulated in the RA but not in the left atria of rabbit hearts, indicating that pressure is the major trigger. A decrease in Serca2a expression was concomitant with a significant decrease in sarcolipin (SLN), possibly indicating a compensatory role of SLN. The decreased expression of SLN was unable to completely restore sarcoplasmic reticulum Ca(2+) uptake function of Serca2a. Functional contractile assessments in isolated trabeculae showed no difference between PAB- and sham-operated rabbits at 1 Hz but displayed an enhanced force development at higher frequencies and in the presence of isoproterenol, while twitch timing was unaffected. Our results indicate that right ventricular mechanical overload due to PAB affects the expression of the Ca(2+)-handling proteins in the RA in rabbits. PMID:19376811

  9. Myogenic responses occur on a beat-to-beat basis in the resting human limb

    PubMed Central

    Fairfax, Seth T.; Padilla, Jaume; Vianna, Lauro C.; Holwerda, Seth W.; Davis, Michael J.

    2014-01-01

    Investigations of human myogenic responses typically use maneuvers that evoke robust changes in transmural pressure. Although this strategy has demonstrated peripheral myogenic responsiveness in the limbs, particularly in glabrous skin of the hand or foot, it has not considered the potential influence of the myogenic mechanism in beat-to-beat blood flow (BF) control during unprovoked rest. In the present study, we examined the interactions of spontaneous beat-to-beat mean arterial pressure (MAP; Finapres) with BF (Doppler ultrasound) supplying the forearm (brachial artery), lower leg (popliteal artery), and hand (ulnar artery) during 10 min of supine rest in healthy young men. Cross-correlation analyses revealed a negative association between MAP and BF, which was more prominent in the forearm than lower leg. The strongest correlation resulted when a −2-heart beat offset of MAP was applied (R = −0.53 ± 0.04 in the forearm and −0.23 ± 0.05 in the leg, P < 0.05), suggesting an ∼2-s delay from instances of high/low MAP to low/high BF. Negatively associated episodes (high MAP/low BF and low MAP/high BF) outnumbered positively associated data (P < 0.05). BF during low MAP values was greater than the steady-state average BF and vice versa. Wrist and ankle occlusion blunted the strength of correlations, homogenized the incidence of MAP and BF pairings, and reduced the magnitude of deviation from steady-state values. In contrast, these relationships were matched or accentuated for hand BF. Overall, these results suggest that myogenic responses are present and occur rapidly in human limbs during rest, overwhelm perfusion pressure gradient influences, and are primarily mediated by the distal limb circulation. PMID:25362138

  10. Finding and feeling the musical beat: striatal dissociations between detection and prediction of regularity.

    PubMed

    Grahn, Jessica A; Rowe, James B

    2013-04-01

    Perception of temporal patterns is critical for speech, movement, and music. In the auditory domain, perception of a regular pulse, or beat, within a sequence of temporal intervals is associated with basal ganglia activity. Two alternative accounts of this striatal activity are possible: "searching" for temporal regularity in early stimulus processing stages or "prediction' of the timing of future tones after the beat is found (relying on continuation of an internally generated beat). To resolve between these accounts, we used functional magnetic resonance imaging (fMRI) to investigate different stages of beat perception. Participants heard a series of beat and nonbeat (irregular) monotone sequences. For each sequence, the preceding sequence provided a temporal beat context for the following sequence. Beat sequences were preceded by nonbeat sequences, requiring the beat to be found anew ("beat finding" condition), or by beat sequences with the same beat rate ("beat continuation"), or a different rate ("beat adjustment"). Detection of regularity is highest during beat finding, whereas generation and prediction are highest during beat continuation. We found the greatest striatal activity for beat continuation, less for beat adjustment, and the least for beat finding. Thus, the basal ganglia's response profile suggests a role in beat prediction, not in beat finding. PMID:22499797

  11. Performance of a Novel Bipolar/Monopolar Radiofrequency Ablation Device on the Beating Heart in an Acute Porcine Model

    PubMed Central

    Saint, Lindsey L.; Lawrance, Christopher P.; Okada, Shoichi; Kazui, Toshinobu; Robertson, Jason O.; Schuessler, Richard B.; Damiano, Ralph J.

    2013-01-01

    SUMMARY Objective Although the advent of ablation technology has simplified and shortened surgery for atrial fibrillation, only bipolar clamps have reliably been able to create transmural lesions on the beating heart. Currently there are no devices capable of reproducibly creating the long linear lesions in the right and left atria needed to perform a Cox-Maze procedure. This study evaluated the performance of a novel suction-assisted radiofrequency device that uses both bipolar and monopolar energy to create lesions from an epicardial approach on the beating heart. Methods Six domestic pigs underwent median sternotomy. A dual bipolar/monopolar radiofrequency ablation device was used to create epicardial linear lesions on the superior and inferior vena cavae, right and left atrial free walls, and right and left atrial appendages. The heart was stained with 2,3,5-triphenyl-tetrazolium chloride and each lesion was cross-sectioned at 5mm intervals. Lesion depth and transmurality were determined. Results Transmurality was documented in 94% of all cross-sections, and 68% of all ablation lines were transmural along their entire length. Tissue thickness was not different between transmural and non-transmural cross-sections (3.1 ± 1.3 and 3.4 ± 2.1, p=0.57, respectively), nor was the anatomic location on the heart (p=0.45 for the distribution). Of the cross-sections located at the end of the ablation line, 11% (8/75) were found to be non-transmural, whereas only 4% (8/195) of cross-sections located within the line of ablation were found to be non-transmural (p=0.04). Logistic regression analysis demonstrated that failure of the device to create transmural lesions was associated with low body temperature (p=0.006), but not with cardiac output (p=0.54). Conclusions This novel device was able to consistently create transmural epicardial lesions on the beating heart, regardless of anatomic location, cardiac output or tissue thickness. The performance of this device was

  12. Findings from Project HeartBeat!

    PubMed Central

    Labarthe, Darwin R.; Dai, Shifan; Day, R. Sue; Fulton, Janet E.; Grunbaum, Jo Anne

    2015-01-01

    Project HeartBeat! was a longitudinal “growth” study of cardiovascular disease (CVD) risk factors and body composition in childhood and adolescence. Its findings demonstrate patterns of change from ages 8 to 18 years in anthropometric indicators of adiposity, blood lipid components, and blood pressure measurements, as well as the varying inter-relations among these patterns. Especially noteworthy are differences among associations between the two components of BMI (kg/m2)—the lean or fat-free mass index, and the fat mass index—and each of several CVD risk factors. Policy development and public health recommendations for CVD prevention beginning in childhood have evolved over 30 years or more. A new impetus to action is the recognized increase in the prevalence of childhood overweight and obesity. Intervention to prevent obesity can have a major impact in preventing CVD risk factors more broadly. Opportunities to strengthen interventions for CVD prevention in childhood and adolescence include updated algorithms for monitoring body composition, blood lipids, and blood pressure throughout childhood and adolescence through use of the Project HeartBeat! study results. PMID:19524150

  13. Motor responses to a steady beat.

    PubMed

    Schaefer, Rebecca S; Overy, Katie

    2015-03-01

    It is increasingly well established that music containing an isochronous pulse elicits motor responses at the levels of both brain and behavior. Such motor responses are often used in pedagogical and clinical practice to induce movement, particularly where motor functions are impaired. However, the complex nature of such apparently universal human responses has, arguably, not received adequate research attention to date. In particular, it should be noted that many adults, including those with disabilities, find it somewhat difficult to synchronize their movements with a beat with perfect accuracy; indeed, perfecting the skill of being musically "in time" can take years of training during childhood. Further research is needed on the nature of both the specificity and range of motor responses that can arise from the perception of a steady auditory pulse, with different populations, musical stimuli, conditions, and required levels of accuracy in order to better understand and capture the potential value of the musical beat as a pedagogical and therapeutic tool. PMID:25773615

  14. The chemical composition of Galactic beat Cepheids

    NASA Astrophysics Data System (ADS)

    Kovtyukh, V.; Lemasle, B.; Chekhonadskikh, F.; Bono, G.; Matsunaga, N.; Yushchenko, A.; Anderson, R. I.; Belik, S.; da Silva, R.; Inno, L.

    2016-08-01

    We determine the metallicity and detailed chemical abundances (α, iron-peak and neutron-capture elements) for the almost complete (18/24) sample of Galactic double mode Cepheids (also called beat Cepheids). Double mode Cepheids are Cepheids that pulsate in two modes simultaneously. We calibrate a new relation between their metallicity and their period ratio P1/P0. This linear relation allows to determine the metallicity of bimodal Cepheids with an accuracy of 0.03 dex in the range of [Fe/H] from +0.2 to -0.5 dex. By extrapolating the relation to Magellanic Clouds beat Cepheids, we provide their metallicity distribution function. Moreover, by using this relation, we also provide the first metallicity estimate for two double-mode F/1O Cepheids located in and beyond the Galactic bulge. Finally, we report the discovery of a super-Lithium rich double mode Cepheid V371 Per which has a Lithium abundance of logA(Li) = 3.54 ± 0.09 dex. Along with V1033 Cyg (which is an ordinary classical Cepheid), it is the second known Cepheid of such type in the Galaxy.

  15. Increased Short-Term Beat-To-Beat Variability of QT Interval in Patients with Acromegaly.

    PubMed

    Orosz, Andrea; Csajbók, Éva; Czékus, Csilla; Gavallér, Henriette; Magony, Sándor; Valkusz, Zsuzsanna; Várkonyi, Tamás T; Nemes, Attila; Baczkó, István; Forster, Tamás; Wittmann, Tibor; Papp, Julius Gy; Varró, András; Lengyel, Csaba

    2015-01-01

    Cardiovascular diseases, including ventricular arrhythmias are responsible for increased mortality in patients with acromegaly. Acromegaly may cause repolarization abnormalities such as QT prolongation and impairment of repolarization reserve enhancing liability to arrhythmia. The aim of this study was to determine the short-term beat-to-beat QT variability in patients with acromegaly. Thirty acromegalic patients (23 women and 7 men, mean age±SD: 55.7±10.4 years) were compared with age- and sex-matched volunteers (mean age 51.3±7.6 years). Cardiac repolarization parameters including frequency corrected QT interval, PQ and QRS intervals, duration of terminal part of T waves (Tpeak-Tend) and short-term variability of QT interval were evaluated. All acromegalic patients and controls underwent transthoracic echocardiographic examination. Autonomic function was assessed by means of five standard cardiovascular reflex tests. Comparison of the two groups revealed no significant differences in the conventional ECG parameters of repolarization (QT: 401.1±30.6 ms vs 389.3±16.5 ms, corrected QT interval: 430.1±18.6 ms vs 425.6±17.3 ms, QT dispersion: 38.2±13.2 ms vs 36.6±10.2 ms; acromegaly vs control, respectively). However, short-term beat-to-beat QT variability was significantly increased in acromegalic patients (4.23±1.03 ms vs 3.02±0.80, P<0.0001). There were significant differences between the two groups in the echocardiographic dimensions (left ventricular end diastolic diameter: 52.6±5.4 mm vs 48.0±3.9 mm, left ventricular end systolic diameter: 32.3±5.2 mm vs 29.1±4.4 mm, interventricular septum: 11.1±2.2 mm vs 8.8±0.7 mm, posterior wall of left ventricle: 10.8±1.4 mm vs 8.9±0.7 mm, P<0.05, respectively). Short-term beat-to-beat QT variability was elevated in patients with acromegaly in spite of unchanged conventional parameters of ventricular repolarization. This enhanced temporal QT variability may be an early indicator of increased liability to

  16. Beat-wave generation of plasmons in semiconductor plasmas

    SciTech Connect

    Berezhiani, V.I.; Mahajan, S.M. |

    1995-08-01

    It is shown that in semiconductor plasmas, it is possible to generate large amplitude plasma waves by the beating of two laser beams with frequency difference close to the plasma frequency. For narrow gap seimconductors (for example n-type InSb), the system can simulate the physics underlying beat wave generation in relativistic gaseous plasmas.

  17. Movement Instruction to Facilitate Beat Competency in Instrumental Music

    ERIC Educational Resources Information Center

    Conway, Colleen; Marshall, Herbert; Hartz, Barry

    2014-01-01

    This article offers instrumental directors at all levels some suggestions for the use of movement to facilitate "beat competency". We use the term beat competency to refer to a musician's ability to play with a consistent sense of pulse and balanced subdivision, as well as the eventual ability to bring that sense of pulse to reading…

  18. Time-domain analysis of beat-to-beat variability of repolarization morphology in patients with ischemic cardiomyopathy.

    PubMed

    Burattini, L; Zareba, W

    1999-01-01

    There is growing evidence that beat-to-beat changes in ventricular repolarization contribute to increased vulnerability to ventricular arrhythmias. Beat-to-beat repolarization variability is usually measured in the electrocardiogram (ECG) by tracking consecutive QT or RT intervals. However, these measurements strongly depend on the accurate identification of T-wave endpoints, and they do not reflect changes in repolarization morphology. In this article, we propose a new computerized time-domain method to measure beat-to-beat variability of repolarization morphology without the need to identify T-wave endpoints. The repolarization correlation index (RCI) is computed for each beat to determine the difference between the morphology of repolarization within a heart-rate dependent repolarization window compared to a template (median) repolarization morphology. The repolarization variability index (RVI) describes the mean value of repolarization correlation in a studied ECG recording. To validate our method, we analyzed repolarization variability in 128-beat segments from Holter ECG recordings of 42 ischemic cardiomyopathy (ICM) patients compared to 36 healthy subjects. The ICM patients had significantly higher values of RVI than healthy subjects (in lead X: 0.045 +/- 0.035 vs. 0.024 +/- 0.010, respectively; P < .001); 18 (43%) ICM patients had RVI values above the 97.5th percentile of healthy subjects (>0.044). No significant correlation was found between the RVI values and the magnitude of heart rate, heart rate variability, QTc interval duration, or ejection fraction in studied ICM patients. In conclusion, our time-domain method, based on computation of repolarization correlation indices for consecutive beats, provides a new approach to quantify beat-to-beat variability of repolarization morphology without the need to identify T-wave endpoints. PMID:10688321

  19. Beat Perception and Sociability: Evidence from Williams Syndrome.

    PubMed

    Lense, Miriam D; Dykens, Elisabeth M

    2016-01-01

    Beat perception in music has been proposed to be a human universal that may have its origins in adaptive processes involving temporal entrainment such as social communication and interaction. We examined beat perception skills in individuals with Williams syndrome (WS), a genetic, neurodevelopmental disorder. Musical interest and hypersociability are two prominent aspects of the WS phenotype although actual musical and social skills are variable. On a group level, beat and meter perception skills were poorer in WS than in age-matched peers though there was significant individual variability. Cognitive ability, sound processing style, and musical training predicted beat and meter perception performance in WS. Moreover, we found significant relationships between beat and meter perception and adaptive communication and socialization skills in WS. Results have implications for understanding the role of predictive timing in both music and social interactions in the general population, and suggest music as a promising avenue for addressing social communication difficulties in WS. PMID:27378982

  20. Beat Perception and Sociability: Evidence from Williams Syndrome

    PubMed Central

    Lense, Miriam D.; Dykens, Elisabeth M.

    2016-01-01

    Beat perception in music has been proposed to be a human universal that may have its origins in adaptive processes involving temporal entrainment such as social communication and interaction. We examined beat perception skills in individuals with Williams syndrome (WS), a genetic, neurodevelopmental disorder. Musical interest and hypersociability are two prominent aspects of the WS phenotype although actual musical and social skills are variable. On a group level, beat and meter perception skills were poorer in WS than in age-matched peers though there was significant individual variability. Cognitive ability, sound processing style, and musical training predicted beat and meter perception performance in WS. Moreover, we found significant relationships between beat and meter perception and adaptive communication and socialization skills in WS. Results have implications for understanding the role of predictive timing in both music and social interactions in the general population, and suggest music as a promising avenue for addressing social communication difficulties in WS. PMID:27378982

  1. Ion heating with beating electrostatic waves.

    PubMed

    Jorns, B; Choueiri, E Y

    2011-02-25

    The nonlinear interaction of a magnetized ion with two beating electrostatic waves (BEW) whose frequencies differ by a cyclotron harmonic can lead, under some conditions [Phys. Rev. E 69, 046402 (2004)], to vigorous acceleration for an ion with arbitrarily low initial velocity. When applied to an ensemble of ions, this mechanism promises enhanced heating over single electrostatic wave (SEW) heating for comparable wave energy densities. The extension of single ion acceleration to heating (SEWH and BEWH) of an ensemble of initially thermalized ions was carried out to compare the processes. Using a numerical solution of the Vlasov equation as a guideline, an analytical expression for the heating level was derived with Lie transforms and was used to show BEWH's superiority over all parameter space. PMID:21405578

  2. Capacitive ECG recording and beat-to-beat interval estimation after major cardiac event.

    PubMed

    Leicht, Lennart; Skobel, Erik; Mathissen, Marcel; Leonhardt, Steffen; Weyer, Soren; Wartzek, Tobias; Reith, Sebastian; Mohler, Werner; Teichmann, Daniel

    2015-08-01

    Today, heart diseases are the most common cause of death in the U.S.. Due to improved healthcare, more and more patients survive a major cardiac event, e.g. a heart attack. However, participation in everyday activity (e.g. driving a car) can be impaired afterwards. Patients might benefit from heart activity monitoring while driving using a capacitive ECG (cECG). However, it is unknown whether cECG is an appropriate monitoring tool for such patients. In this work, first results from a study including 10 patients having survived at least one major cardiac event are presented. It is shown that cECG can be used to diagnose heart rhythm deviations and estimate beat-to-beat intervals similar to conventional ECG. PMID:26738055

  3. A dual collimator design for beat-to-beat measurement of cardiac performance with an Anger camera

    SciTech Connect

    Heller, S.L.; Goodwin, P.N.; Scharf, S.C.; Hardoff, R.; Blaufox, M.D.

    1982-09-01

    A dual collimator was designed for an Anger camera to permit measurement of cardiac performance on a beat-to-beat basis. Special all-purpose (SAP) and special high-sensitivity (SHS) collimator sections can be interchanged without movement of the patient. Thus, left-ventricular regions of interest delineated on SAP multigated images can be transferred to SHS dynamic images to generate beat-to-beat volume curves. Preliminary balloon studies demonstrated an excellent correlation between ejection fractions calculated with the two collimators: r greater than 0.99, n . 17, p less than 0.001. Varying the volume of an adjacent right ventricle balloon failed to alter significantly the count rate from the left ventricle balloon's region of interest. Preliminary results on 12 patients, comparing standard-camera ejection fractions with average beat-to-beat ejection fractions, showed that is is possible to measure cardiac function on a beat-to-beat basis with a single-crystal gamma camera. There was minimal difference between the ejection fractions calculated by the dual-collimator method and a standard gated technique (r . 0.98, n . 12, p less than 0.001).

  4. The Cutaneous Rabbit Revisited

    ERIC Educational Resources Information Center

    Flach, Rudiger; Haggard, Patrick

    2006-01-01

    In the cutaneous rabbit effect (CRE), a tactile event (so-called attractee tap) is mislocalized toward an adjacent attractor tap. The effect depends on the time interval between the taps. The authors delivered sequences of taps to the forearm and asked participants to report the location of one of the taps. The authors replicated the original CRE…

  5. VLDL from Metabolic Syndrome Individuals Enhanced Lipid Accumulation in Atria with Association of Susceptibility to Atrial Fibrillation

    PubMed Central

    Lee, Hsiang-Chun; Lin, Hsin-Ting; Ke, Liang-Yin; Wei, Chi; Hsiao, Yi-Lin; Chu, Chih-Sheng; Lai, Wen-Ter; Shin, Shyi-Jang; Chen, Chu-Huang; Sheu, Sheng-Hsiung; Wu, Bin-Nan

    2016-01-01

    Metabolic syndrome (MetS) represents a cluster of metabolic derangements. Dyslipidemia is an important factor in MetS and is related to atrial fibrillation (AF). We hypothesized that very low density lipoproteins (VLDL) in MetS (MetS-VLDL) may induce atrial dilatation and vulnerability to AF. VLDL was therefore separated from normal (normal-VLDL) and MetS individuals. Wild type C57BL/6 male mice were divided into control, normal-VLDL (nVLDL), and MetS-VLDL (msVLDL) groups. VLDL (15 µg/g) and equivalent volumes of saline were injected via tail vein three times a week for six consecutive weeks. Cardiac chamber size and function were measured by echocardiography. MetS-VLDL significantly caused left atrial dilation (control, n = 10, 1.64 ± 0.23 mm; nVLDL, n = 7, 1.84 ± 0.13 mm; msVLDL, n = 10, 2.18 ± 0.24 mm; p < 0.0001) at week 6, associated with decreased ejection fraction (control, n = 10, 62.5% ± 7.7%, vs. msVLDL, n = 10, 52.9% ± 9.6%; p < 0.05). Isoproterenol-challenge experiment resulted in AF in young msVLDL mice. Unprovoked AF occurred only in elderly msVLDL mice. Immunohistochemistry showed excess lipid accumulation and apoptosis in msVLDL mice atria. These findings suggest a pivotal role of VLDL in AF pathogenesis for MetS individuals. PMID:26805814

  6. Effects of spironolactone towards rabbit atrial remodeling with rapid pacing.

    PubMed

    Wang, Lian-Fa; Gu, Lei; Huang, Meng-Xun; Zhou, Wen-Bing; Li, Hua; Zhang, Bang-Zhu

    2016-01-01

    This study aimed to observe the effects of spironolactone towards the rabbit atrial remodeling with rapid atrial pacing (RAP). 30 rabbits were randomly divided into control group, RAP group and spironolactone group, with 10 rabbits in each group. RAP was performed at the speed of 800 beats/min for 8 h, atrial effective refractory period (AERP) was determined before and at the 1(st), 2(nd), 4(th), 6(th) and 8(th) of the pacing, the expressions of atrial muscular calcium channel α1C subunit and β1 subunit mRNA were performed the RT-PCR detection, and ultrastructural changes of atrial myocytes were observed. AERP of RAP group shortened, with poor frequency adaptability; the expressions of calcium channel α1C subunit and β1 subunit mRNA decreased 22% and 26%, respectively, when compared with the control group; ultrastructure of atrial myocytes changed significantly. AERP of spironotlactone group shortened less that RAP group, and the frequency adaptability was maintained, the decreased expressions of calcium channel α1C subunit and β1 subunit mRNA significantly reduced. RAP could cause atrial remodeling, while spironolactone could inhibit RAP-induced atrial remodeling. PMID:26826809

  7. Robust inter-beat interval estimation in cardiac vibration signals.

    PubMed

    Brüser, C; Winter, S; Leonhardt, S

    2013-02-01

    Reliable and accurate estimation of instantaneous frequencies of physiological rhythms, such as heart rate, is critical for many healthcare applications. Robust estimation is especially challenging when novel unobtrusive sensors are used for continuous health monitoring in uncontrolled environments, because these sensors can create significant amounts of potentially unreliable data. We propose a new flexible algorithm for the robust estimation of local (beat-to-beat) intervals from cardiac vibration signals, specifically ballistocardiograms (BCGs), recorded by an unobtrusive bed-mounted sensor. This sensor allows the measurement of motions of the body which are caused by cardiac activity. Our method requires neither a training phase nor any prior knowledge about the morphology of the heart beats in the analyzed waveforms. Instead, three short-time estimators are combined using a Bayesian approach to continuously estimate the inter-beat intervals. We have validated our method on over-night BCG recordings from 33 subjects (8 normal, 25 insomniacs). On this dataset, containing approximately one million heart beats, our method achieved a mean beat-to-beat interval error of 0.78% with a coverage of 72.69%. PMID:23343518

  8. Understanding women's attitudes towards wife beating in Zimbabwe.

    PubMed Central

    Hindin, Michelle J.

    2003-01-01

    OBJECTIVE: To investigate the factors associated with attitudes towards wife beating among women in partnerships in Zimbabwe in order to assist public health practitioners in preventing intimate partner violence (IPV). METHODS: A nationally representative survey of 5907 women of reproductive age (15-49 years) was conducted in Zimbabwe. Women were asked about their attitudes towards wife beating in five situations. The survey included sociodemographic characteristics, partnership characteristics, and household decision-making. FINDINGS: Over half of all women in Zimbabwe (53%) believed that wife beating was justified in at least one of the five situations. Respondents were most likely to find wife beating justified if a wife argued with her spouse (36%), neglected her children (33%), or went out without telling her spouse (30%). Among women in partnerships (n=3077), younger age, living in rural areas, lower household wealth, schooling at a lower level than secondary, and lower occupational status were associated with women reporting that wife beating is justified. Women who reported that they make household decisions jointly with their partners were less likely to say that wife beating is justified. CONCLUSIONS: Zimbabwe has a long way to go in preventing IPV, particularly because the younger generation of women is significantly more likely to believe that wife beating is justified compared with older women. Given the current social and political climate in Zimbabwe, finding means to negotiate rather than settle conflict through violence is essential from the household level to the national level. PMID:12973642

  9. Psychoacoustic Factors in Musical Intonation: Beats, Interval Tuning, and Inharmonicity.

    NASA Astrophysics Data System (ADS)

    Keislar, Douglas Fleming

    Three psychoacoustic experiments were conducted using musically experienced subjects. In the first two experiments, the interval tested was the perfect fifth F4-C5; in the final one it was the major third F4-A4. The beat rate was controlled by two different methods: (1) simply retuning the interval, and (2) frequency-shifting one partial of each pair of beating partials without changing the overall interval tuning. The second method introduces inharmonicity. In addition, two levels of beat amplitude were introduced by using either a complete spectrum of 16 equal-amplitude partials per note, or by deleting one partial from each pair of beating partials. The results of all three experiments indicate that, for these stimuli, beating does not contribute significantly to the percept of "out-of-tuneness," because it made no difference statistically whether the beat amplitude was maximal or minimal. By contrast, mistuning the interval was highly significant. For the fifths, frequency-shifting the appropriate partials had about as much effect on the perceived intonation as mistuning the interval. For thirds, this effect was weaker, presumably since there were fewer inharmonic partials and they were higher in the harmonic series. Subjects were less consistent in their judgments of thirds than of fifths, perhaps because the equal-tempered and just thirds differ noticeably, unlike fifths. Since it is unlikely that beats would be more audible in real musical situations than under these laboratory conditions, these results suggest that the perception of intonation in music is dependent on the actual interval tuning rather than the concomitant beat rate. If beating partials are unimportant vis-a-vis interval tuning, this strengthens the argument for a cultural basis for musical intonation and scales, as opposed to the acoustical basis set forth by Helmholtz and others.

  10. Investigation of beat-waves generation with high efficiency

    SciTech Connect

    Song, W.; Shi, Y. C.; Deng, Y. Q.; Zhu, X. X.; Zhang, Z. Q.; Hu, X. G.

    2013-10-21

    A method for generating high power beating radio-frequency wave with high conversion efficiency is proposed. Based on Cherenkov radiation, two longitudinal resonant modes are excited simultaneously and interacted with intense electron beam synchronously. An experiment was carried out and beat-waves with an average power of about 2.3 GW, frequencies of 9.29 GHz and 10.31 GHz, and efficiency of about 40% were obtained. Through controlling the electron energy, the amplitude proportions of the two resonant modes are altered, and different beat-wave patterns are formed.

  11. Beliefs about wife beating: an exploratory study with Lebanese students.

    PubMed

    Obeid, Nadine; Chang, Doris F; Ginges, Jeremy

    2010-06-01

    In recent years, there has been a growing interest in understanding the sociocultural contexts and risk factors for domestic violence in the Arab world. This study provides an analysis of the religious, legal, and familial contexts of domestic violence in Lebanon and assesses contemporary attitudes toward women and wife beating in a sample of 206 Lebanese university students. Gender, patriarchal attitudes, religion, childhood experiences with family violence, and mother's employment status were investigated as predictors of attitudes toward wife beating. Consistent with feminist theories of wife abuse, gender and attitudes toward women's roles emerged as the strongest predictors of beliefs about wife beating. PMID:20445079

  12. Feathering collisions in beating reed simulation

    NASA Astrophysics Data System (ADS)

    Smyth, Tamara; Abel, Jonathan S.; Smith, Julius O.

    2003-10-01

    Pressure controlled valves are the primary sound production mechanisms for woodwind and brass musical instruments, as well as for many bioacoustic vocal systems such as the larynx and syrinx (the vocal organ in birds). During sound production, air flow sets a reed or membrane into motion creating a variable height in the valve channel and, potentially, periodically closing the channel completely. Depending on how this event is handled, an abrupt termination of air flow between open and closed states can cause undesirable discontinuities and inaccuracies in a discrete-time simulation-particularly at relatively low audio sampling rates. A solution was developed by re-examining the behavior of the differential equation governing volume flow through a pressure-controlled valve, paying particular attention to this rather troublesome transition. A closed-form solution for the time evolution of volume flow is given and used to derive an update for volume flow. The result is a smoother, more accurate, and nearly alias-free transition from open to closed. ``Feathered collisions'' of this nature can refine the sound quality produced by the numerical simulation of beating reeds, such as in clarinets, at typical audio sampling rates.

  13. Beat-to-beat three-dimensional ECG variability predicts ventricular arrhythmia in ICD recipients

    PubMed Central

    Tereshchenko, Larisa G.; Han, Lichy; Cheng, Alan; Marine, Joseph E.; Spragg, David D.; Sinha, Sunil; Dalal, Darshan; Calkins, Hugh; Tomaselli, Gordon F.; Berger, Ronald D.

    2010-01-01

    Background Methodological difficulties associated with QT measurements prompt search for new ECG markers of repolarization heterogeneity. Objective We hypothesized that beat-to-beat 3-dimensional vectorcardiogram variability predicts ventricular arrhythmia (VA) in patients with structural heart disease left ventricular systolic dysfunction and implanted ICD. Methods Baseline orthogonal ECGs were recorded in 414 patients with structural heart disease [mean age 59.4±12.0; 280 whites (68%) and 134 blacks (32%)] at rest before implantation of ICD for primary prevention of sudden cardiac death. R and T peaks of 30 consecutive sinus beats were plotted in 3-D to form an R peaks cloud and a T peaks cloud. The volume of the peaks cloud was calculated as the volume within the convex hull. Patients were followed at least 6 months; sustained VA with appropriate ICD therapies served as an endpoint. Results During a mean follow-up time of 18.4±12.5 months, 61 of the 414 patients (14.73% or 9.6% per person-year of follow-up) experienced sustained VA with appropriate ICD therapies: 41 of them were whites and 20 were blacks. In the multivariate Cox model that included inducibility of VA and use of beta-blockers, the highest tertile of T/R peaks cloud volume ratio significantly predicted VA (HR 1.68 95% CI 1.01–2.80;p=0.046) in all patients. T peaks cloud volume and T/R peaks cloud volume ratio were significantly smaller in blacks [0.09 (0.04–0.15) vs. 0.11 (0.06–0.22), p=0.002]. Conclusion Relatively large T peaks cloud volume is associated with increased risk of VA in patients with structural heart disease and systolic dysfunction. PMID:20816873

  14. Restoring Blood Flow Beats Exercise for Poor Leg Circulation

    MedlinePlus

    ... news/fullstory_158683.html Restoring Blood Flow Beats Exercise for Poor Leg Circulation Opening vessels could prevent ... restore blood flow may have greater benefits than exercise, preliminary research suggests. People with peripheral artery disease ( ...

  15. Race May Influence Risk for Irregular Heart Beat

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_158687.html Race May Influence Risk for Irregular Heart Beat Whites ... between the heart rhythm disorder atrial fibrillation and race, a new study says. Whites with heart failure ...

  16. Phase shifting and the beating of complex waves

    NASA Astrophysics Data System (ADS)

    Keeports, David

    2011-03-01

    At the introductory level, the demonstration and analysis of sound beating is usually limited to the superposition of two purely sinusoidal waves with equal amplitudes and very similar frequencies. Under such conditions, an observer hears the periodic variation of the loudness of a sound with an unchanging timbre. On the other hand, when complex waves with very similar frequencies are superimposed, each harmonic beats with a frequency proportional to the frequency of the harmonic. Consequently, the resulting sound exhibits a subtle variation of timbre with time. This article extends the normal introductory discussion of beating and explains why electronic phase shifters, devices familiar to many musicians, can produce the sound of beating complex waves.

  17. Keep the Beat Recipes | NIH MedlinePlus the Magazine

    MedlinePlus

    ... turn Javascript on. Feature: High Blood Pressure Keep the Beat Recipes Past Issues / Fall 2011 Table of ... and Blood Institute To Improve Blood Pressure, Try the DASH Diet If you're one of the ...

  18. Mercury Beating Heart: Modifications to the Classical Demonstration

    ERIC Educational Resources Information Center

    Najdoski, Metodija; Mirceski, Valentin; Petrusevski, Vladimir M.; Demiri, Sani

    2007-01-01

    The mercury beating heart (MBH) is a commonly performed experiment, which is based on varying oxidizing agents and substituting other metals for iron. Various modified versions of the classical demonstration of the experiment are presented.

  19. Beat the Winter Blues: Shedding Light on Seasonal Sadness

    MedlinePlus

    ... exit disclaimer . Subscribe Beat the Winter Blues Shedding Light on Seasonal Sadness As the days get shorter, ... clock” responds to cues in your surroundings, especially light and darkness. During the day, your brain sends ...

  20. Intertrial auditory neural stability supports beat synchronization in preschoolers

    PubMed Central

    Carr, Kali Woodruff; Tierney, Adam; White-Schwoch, Travis; Kraus, Nina

    2016-01-01

    The ability to synchronize motor movements along with an auditory beat places stringent demands on the temporal processing and sensorimotor integration capabilities of the nervous system. Links between millisecond-level precision of auditory processing and the consistency of sensorimotor beat synchronization implicate fine auditory neural timing as a mechanism for forming stable internal representations of, and behavioral reactions to, sound. Here, for the first time, we demonstrate a systematic relationship between consistency of beat synchronization and trial-by-trial stability of subcortical speech processing in preschoolers (ages 3 and 4 years old). We conclude that beat synchronization might provide a useful window into millisecond-level neural precision for encoding sound in early childhood, when speech processing is especially important for language acquisition and development. PMID:26760457

  1. Rabbit care and husbandry.

    PubMed

    Bradley, Teresa

    2004-05-01

    This article provides information for the veterinary staff to be better prepared to care for the special needs of rabbit patients as they are presented in increased frequency for veterinary care. Housing, nutrition,restraint, and recognizing illness are covered in detail. Descriptions of techniques for blood collection, oral medication administration, and injection sites are included. Preventive care recommendations for examinations from first visit to geriatric visits are outlined as well as indications for spaying and neutering. Also provided are lists that will aid the veterinary staff in providing instructions when the appointment is made, recommendations for boarding, surgical, and anesthetic considerations and clinical signs that are associated with pain in rabbits. PMID:15145392

  2. Rabbits killing birds revisited.

    PubMed

    Zhang, Jimin; Fan, Meng; Kuang, Yang

    2006-09-01

    We formulate and study a three-species population model consisting of an endemic prey (bird), an alien prey (rabbit) and an alien predator (cat). Our model overcomes several model construction problems in existing models. Moreover, our model generates richer, more reasonable and realistic dynamics. We explore the possible control strategies to save or restore the bird by controlling or eliminating the rabbit or the cat when the bird is endangered. We confirm the existence of the hyperpredation phenomenon, which is a big potential threat to most endemic prey. Specifically, we show that, in an endemic prey-alien prey-alien predator system, eradication of introduced predators such as the cat alone is not always the best solution to protect endemic insular prey since predator control may fail to protect the indigenous prey when the control of the introduced prey is not carried out simultaneously. PMID:16529776

  3. Beat frequency ultrasonic microsphere contrast agent detection system

    NASA Technical Reports Server (NTRS)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  4. Biodegradable fixation of rabbit osteotomies.

    PubMed

    Vainionpää, S; Vihtonen, K; Mero, M; Pätiälä, H; Rokkanen, P; Kilpikari, J; Törmälä, P

    1986-06-01

    Osteotomies of the tibial diaphysis were operatively fixed with biodegradable implants in 44 rabbits. Polyglycolic acid (PGA)/polylactic acid (PLA) copolymer implants reinforced with 7 per cent carbon fibre and overlaid with gold were used in 24 rabbits. Poly-beta-hydroxy butyric acid (PHBA) with carbon fibre reinforcement and gold surfacing were used in 20 rabbits. No external support was used. Unsatisfactory results were achieved with the PGA/PLA copolymer implants. Better results were achieved in 15 out of 20 rabbits whose osteotomies were fixed with carbon fibre-reinforced PHBA implants. PMID:3739665

  5. Threshold tracking pacing based on beat by beat evoked response detection: clinical benefits and potential problems.

    PubMed

    Duru, F; Bauersfeld, U; Schüller, H; Candinas, R

    2000-10-01

    Continuous monitoring of pacemaker stimulation thresholds and automatic adjustment of pacemaker outputs were among the longstanding goals of the pacing community. The first clinically successful implementation of threshold tracking pacing was the Autocapture feature which has accomplished automatic ventricular capture verification for every single stimulus by monitoring the Evoked Response (ER) signal resulting from myocardial depolarization. The Autocapture feature not only decreases energy consumption by keeping the stimulation output slightly above the actual threshold, but also increases patient safety by access to high-output back-up pulses if there is loss of capture. Furthermore, it provides valuable documentation of stimulation thresholds over time and serves as a valuable research tool. Current limitations for its widespread use include the requirements for implantation of bipolar low polarization leads and unipolar pacing in the ventricle. Fusion/pseudofusion beats with resultant insufficient or even non-existent ER signal amplitudes followed by unnecessary delivery of back-up pulses and a possible increase in pacemaker output is not an uncommon observation unique to the Autocapture feature. The recent incorporation of the Autocapture algorithm in dual chamber pacemakers has been challenging because of more frequent occurrence of fusion/pseudofusion beats in the presence of normal AV conduction. Along with a review of the previously published studies and our clinical experience, this article discusses the clinical advantages and potential problems of Autocapture. PMID:11046190

  6. Assessment of efficacy of proarrhythmia biomarkers in isolated rabbit hearts with attenuated repolarization reserve.

    PubMed

    Orosz, Szabolcs; Sarusi, Annamária; Csík, Norbert; Papp, Julius Gy; Varró, András; Farkas, Sándor; Forster, Tamás; Farkas, Attila S; Farkas, András

    2014-09-01

    Isolated hearts with reduced repolarization reserve would be suitable for assessing the proarrhythmic liability of drugs. However, it is not known which proarrhythmia biomarkers indicate the increased susceptibility to torsades de pointes arrhythmia (TdP) in such experimental setting. Thus, we estimated the efficacy of proarrhythmia biomarkers in isolated hearts with attenuated repolarization reserve. Langendorff-perfused rabbit hearts were used. Repolarization reserve was reduced by concomitant inhibition of the rapid (IKr) and slow (IKs) delayed rectifier potassium currents by dofetilide and HMR-1556, respectively. Rate corrected QT (QTc) interval and beat-to-beat variability of the QT interval measured in sinus rhythm or irrespective of rhythm even during arrhythmias (sinus and absolute QT variability, respectively) were tested. QTc failed to predict increased proarrhythmic risk. Sinus QT variability indicated proarrhythmic liability when low concentration of dofetilide was used. However, when arrhythmias compromised sinus variability measurement during coperfusion of catecholamines and elevated concentration of dofetilide, only absolute QT variability indicated increased proarrhythmic risk. Absolute QT variability parameters seem to be the most practical and sensitive biomarkers of proarrhythmic liability in rabbit hearts with reduced repolarization reserve. Absolute QT variability parameters could serve as surrogates for torsades de pointes in drug-safety investigations in isolated rabbit hearts with attenuated repolarization reserve. PMID:24887684

  7. Positive airway pressure improves nocturnal beat-to-beat blood pressure surges in obesity hypoventilation syndrome with obstructive sleep apnea.

    PubMed

    Carter, Jason R; Fonkoue, Ida T; Grimaldi, Daniela; Emami, Leila; Gozal, David; Sullivan, Colin E; Mokhlesi, Babak

    2016-04-01

    Positive airway pressure (PAP) treatment has been shown to have a modest effect on ambulatory blood pressure (BP) in patients with obstructive sleep apnea (OSA). However, there is a paucity of data on the effect of PAP therapy on rapid, yet significant, BP swings during sleep, particularly in obesity hypoventilation syndrome (OHS). The present study hypothesizes that PAP therapy will improve nocturnal BP on the first treatment night (titration PAP) in OHS patients with underlying OSA, and that these improvements will become more significant with 6 wk of PAP therapy. Seventeen adults (7 men, 10 women; age 50.4 ± 10.7 years, BMI 49.3 ± 2.4 kg/m(2)) with OHS and clinically diagnosed OSA participated in three overnight laboratory visits that included polysomnography and beat-to-beat BP monitoring via finger plethysmography. Six weeks of PAP therapy, but not titration PAP, lowered mean nocturnal BP. In contrast, when nocturnal beat-to-beat BPs were aggregated into bins consisting of at least three consecutive cardiac cycles with a >10 mmHg BP surge (i.e., Δ10-20, Δ20-30, Δ30-40, and Δ>40 mmHg), titration, and 6-wk PAP reduced the number of BP surges per hour (time × bin,P< 0.05). PAP adherence over the 6-wk period was significantly correlated to reductions in nocturnal systolic (r= 0.713,P= 0.001) and diastolic (r= 0.497,P= 0.043) BP surges. Despite these PAP-induced improvements in nocturnal beat-to-beat BP surges, 6 wk of PAP therapy did not alter daytime BP. In conclusion, PAP treatment reduces nocturnal beat-to-beat BP surges in OHS patients with underlying OSA, and this improvement in nocturnal BP regulation was greater in patients with higher PAP adherence. PMID:26818059

  8. [Non-heart-beating donors are ineligible].

    PubMed

    Heide, W

    2016-02-01

    The death of the donor is a mandatory prerequisite for organ transplantation (dead donor rule) worldwide. It is a medical, legal and ethical consensus to accept the concept of brain death, as first proposed in 1968 by the ad hoc committee of the Harvard Medical School, as a certain criterion of death. In isolated cases where the diagnosis of brain death was claimed to be wrong, it could be demonstrated that the diagnostic procedure for brain death had not been correctly performed. In March 2014 a joint statement by the German neuromedical societies emphasized that 1) the diagnosis of brain death is one of the safest diagnoses in medicine if performed according to accepted medical standards and criteria and 2) the concept of non-heart-beating donors (NHBD, i. e. organ donation after an arbitrarily defined duration of circulatory and cardiac arrest) practiced in some European countries must be absolutely rejected because it implicates a high risk of diagnostic error. According to the current literature it is unclear at what time cardiac and circulatory arrest is irreversible and leads to irreversible cessation of all functions of the entire brain including the brainstem, even though clinical signs of cessation of brain functions are always found after 10 min. Furthermore, is it often an arbitrary decision to exactly define the duration of cardiac arrest if continuous echocardiographic monitoring has not been carried out from the very beginning. Last but not least there are ethical concerns against the concept of NHBD because it might influence therapeutic efforts to resuscitate a patient with cardiac arrest. Therefore, the German Medical Council (BÄK) has repeatedly rejected the concept of NHBD for organ transplantation since 1995. PMID:26830897

  9. Beating of wives: a cross-cultural perspective.

    PubMed

    Campbell, J C

    1985-01-01

    This paper reports a more in-depth analysis of wife beating from a cross-cultural perspective. As background for the analysis, the methodological, operationalization, and measurement in previous cross-cultural research on wife beating is examined. Subsequently, a review of findings from these studies and the theoretical explanations from selected disciplines are presented as the basis of selection of variables expected to affect the presence and severity of wife abuse in a given culture. These variables are then examined with evidence from female perspective ethnographies on eleven different societies. This cross-cultural analysis of wife beating has illuminated more issues of methodology and variations of patterns than it has answered any questions about what may increase the frequency and severity of wife-beating in a given culture. It is possible that the beating of wives is a personal expression of hostility against women that may be expressed in addition to, or instead of, institutionalized aggression toward women in that culture. As such, wife beating can take many forms. It can be an indication of manhood, a means of personal control, a reflection of personal animosity, and an expression of sexual jealousy. These personal forms would be paralleled by societal expression such as gang rape, control of women by exclusion from the public sphere, general hostility between sexes, and the virtue of women becoming an issue of extended family and community honor. In conclusion, the importance of the variables is summarized and directions for future cross-cultural research on wife beating are suggested. PMID:12295646

  10. Early repolarization as a predictor of premature ventricular beats.

    PubMed

    Matoshvili, Z T; Petriashvili, Sh G; Archadze, A T; Azaladze, I G

    2015-02-01

    Early repolarization pattern (ERP) is a common ECG variant, characterized by J point elevation manifested either as terminal QRS slurring (the transition from the QRS segment to the ST segment) or notching (a positive deflection inscribed on terminal QRS complex) associated with concave upward ST-segment elevation and prominent T waves in at least two contiguous leads. Aim of this observational study was to compare number of premature ventricular beats in the different groups of patients with early repolarization. The result of this observational study shows that there are: 1,74 fold higher number of premature ventricular beats in 41-74 year subgroup VS 19-40 year subgroup; 1,31 fold higher number of premature ventricular beats in male subgroup VS female subgroup (But this difference is not statistically significant, because t=1,49, p=0,141); 2,85 fold higher number of premature ventricular beats in CAD+ERP subgroup VS ERP without CAD subgroup; 1,74 fold higher number of premature ventricular beats in HF+ERP subgroup VS ERP without HF subgroup; 1,81 fold higher number of premature ventricular beats in CAD+ERP subgroup VS CAD without ERP subgroup; 1,58 fold higher number of premature ventricular beats in HF+ERP subgroup VS HF without ERP subgroup; So, CAD+ERP is very arrhythmogenic condition, after this is HF+ERP, Then Age. This study shows that ERP independently increase number of PVB in different groups (CAD, HF). This is principally new and very important result. Also the number of patients is enough to make this conclusion. PMID:25802448

  11. Rabbit models of cardiac mechano-electric and mechano-mechanical coupling.

    PubMed

    Quinn, T Alexander; Kohl, Peter

    2016-07-01

    Cardiac auto-regulation involves integrated regulatory loops linking electrics and mechanics in the heart. Whereas mechanical activity is usually seen as 'the endpoint' of cardiac auto-regulation, it is important to appreciate that the heart would not function without feed-back from the mechanical environment to cardiac electrical (mechano-electric coupling, MEC) and mechanical (mechano-mechanical coupling, MMC) activity. MEC and MMC contribute to beat-by-beat adaption of cardiac output to physiological demand, and they are involved in various pathological settings, potentially aggravating cardiac dysfunction. Experimental and computational studies using rabbit as a model species have been integral to the development of our current understanding of MEC and MMC. In this paper we review this work, focusing on physiological and pathological implications for cardiac function. PMID:27208698

  12. Pathogenicity of rotavirus in rabbits.

    PubMed Central

    Thouless, M E; DiGiacomo, R F; Deeb, B J; Howard, H

    1988-01-01

    The role of rotavirus in diarrheal disease of rabbits was investigated, and a model for human rotavirus infection was established. Orogastric inoculation of 8- and 12-week-old New Zealand White rabbits with a rabbit strain of rotavirus (L:ALA:84) resulted in fecal shedding of virus for 6 to 8 days from 2 to 5 days after inoculation. Most rabbits exhibited diarrhea, coincident with the onset of viral shedding, which persisted for 2 to 4 days. Diarrhea was characterized by soft or fluid stools and fecal staining of the perineum. Inoculation of 3-week-old rabbits resulted in a briefer period of viral shedding and diarrhea of a milder nature. Histopathologic examination during the period of viral shedding revealed a mild, nonsuppurative enteritis. Inoculated rabbits exhibited antibodies in serum to rotavirus by enzyme-linked immunosorbent assay. Sham-inoculated or uninoculated rabbits maintained in the same cage or the same room with inoculated rabbits acquired rotavirus infection. The mild diarrheal disease which resulted with a rotavirus isolate from severe field cases suggests that cofactors were involved. Images PMID:2838507

  13. Neuromuscular lesions in restrained rabbits.

    PubMed

    Mendlowski, B

    1975-01-01

    Ten of 16 rabbits restrained 6 h daily for 35 days developed focal to diffuse degeneration of the sciatic nerves. Very small necrotic areas also were found in the skeletal muscles of seven of 16 rabbits, but the muscle lesions did not correlate with the nerve changes. PMID:180647

  14. Effect of platelet activating factor (PAF) on pulmonary circulation in isolated rabbit lung.

    PubMed

    Comellas, A; Tristano, S; Pesce, L; Friedman, E; Marcano, H; Sánchez de León, R

    1999-03-01

    Platelet activating factor (PAF) has been implicated in the pathophysiology of acute lung injury. The aim of this work is to study the effect of PAF on isolated and perfused rabbit lungs with blood and with a blood-free solution. 24 isolated and perfused rabbit lungs have been used: 8 control preparations (CP), 4 vehicles preparations (VP), 8 PAF preparations (PP) to which we administered PAF (1 microg/Kg of rabbit weight) and 4 acellular preparations (AP) with the same dose of PAF as in PP but dissolved in BSA-Krebs buffer solution. In the preparations pulmonary artery pressure (Ppa), airway pressure (Paw), left atria pressure (Pla) and fluid filtration rate (FFR) were registered. Ppa resulted in a significant difference in AP vs PP, with a value of 21 cm of water (CI 95%: 12-26) vs 205.1 cm of water (CI 95%: 141.3 - 271) respectively. A increase in FFR was observed in PP but it did not occur in AP, the difference being statistically significant: 5.515 g/min (CI 95 %: 2.425 - 8.865) vs 0.049 g/min (CI 95%: 0.008 - 0.32) respectively. Paw was statistically different in PP vs AP, with a value of 14.3 cm of water (CI 95%: 11.57 - 16.7) vs 8.5 cm of water (CI 95%: 8-9) respectively. These results suggest that PAF does not have a direct effect on the endothelium or smooth muscle in the production of lung edema. PMID:10494654

  15. A Structural Basis for How Motile Cilia Beat

    PubMed Central

    Satir, Peter; Heuser, Thomas; Sale, Winfield S.

    2014-01-01

    The motile cilium is a mechanical wonder, a cellular nanomachine that produces a high-speed beat based on a cycle of bends that move along an axoneme made of 9+2 microtubules. The molecular motors, dyneins, power the ciliary beat. The dyneins are compacted into inner and outer dynein arms, whose activity is highly regulated to produce microtubule sliding and axonemal bending. The switch point hypothesis was developed long ago to account for how sliding in the presence of axonemal radial spoke–central pair interactions causes the ciliary beat. Since then, a new genetic, biochemical, and structural complexity has been discovered, in part, with Chlamydomonas mutants, with high-speed, high-resolution analysis of movement and with cryoelectron tomography. We stand poised on the brink of new discoveries relating to the molecular control of motility that extend and refine our understanding of the basic events underlying the switching of arm activity and of bend formation and propagation. PMID:26955066

  16. Non-heart-beating organ donation: process and review.

    PubMed

    Edwards, J M; Hasz, R D; Robertson, V M

    1999-05-01

    To combat the national shortage of donor organs and meet the needs of more than 60,000 patients awaiting transplant, many organ procurement organizations have reevaluated non-heart-beating organ donation (NHBD) as one solution. Non-heart-beating donation is the process by which organs are recovered from patients after the pronouncement of death by cardiopulmonary criteria. Recent media reports have misled health care providers to believe that this is a new donation procedure; however, NHBD provided the foundation for modern clinical transplantation. This article describes non-heart-beating donor evaluation criteria, the donation process, associated ethical considerations and the role of the advance practice nurse in assisting families with this end-of-life decision. A case study will be presented followed by a summary of transplant recipient patient and graft survival outcomes. PMID:10578715

  17. On readout of vibrational qubits using quantum beats.

    PubMed

    Shyshlov, Dmytro; Berrios, Eduardo; Gruebele, Martin; Babikov, Dmitri

    2014-12-14

    Readout of the final states of qubits is a crucial step towards implementing quantum computation in experiment. Although not scalable to large numbers of qubits per molecule, computational studies show that molecular vibrations could provide a significant (factor 2-5 in the literature) increase in the number of qubits compared to two-level systems. In this theoretical work, we explore the process of readout from vibrational qubits in thiophosgene molecule, SCCl2, using quantum beat oscillations. The quantum beats are measured by first exciting the superposition of the qubit-encoding vibrational states to the electronically excited readout state with variable time-delay pulses. The resulting oscillation of population of the readout state is then detected as a function of time delay. In principle, fitting the quantum beat signal by an analytical expression should allow extracting the values of probability amplitudes and the relative phases of the vibrational qubit states. However, we found that if this procedure is implemented using the standard analytic expression for quantum beats, a non-negligible phase error is obtained. We discuss the origin and properties of this phase error, and propose a new analytical expression to correct the phase error. The corrected expression fits the quantum beat signal very accurately, which may permit reading out the final state of vibrational qubits in experiments by combining the analytic fitting expression with numerical modelling of the readout process. The new expression is also useful as a simple model for fitting any quantum beat experiments where more accurate phase information is desired. PMID:25494748

  18. Characterization of fluid transport due to multiciliary beating

    NASA Astrophysics Data System (ADS)

    Lukens, Sarah; Yang, Xingzhou; Fauci, Lisa

    2008-11-01

    Understanding fluid transport caused by beating cilia can give insight on biological systems such as transport of respiratory mucus, ovum transport in the oviduct, and feeding currents around unicellular organisms. Here we investigate fluid transport due to coordinated beating of motile cilia based upon a computational model that couples their internal force generating mechanisms with external fluid dynamics. Velocity field data is used to identify Lagrangian Coherent Structures (LCS) within the domain. These coherent structures give spatial information on fluid mixing and nutrient transport within this dynamic environment.

  19. Constant magnetic field influence on a heart beat in rats

    SciTech Connect

    Lazetic, B.; Pekaric-Nadj, N.; Kasas-Lazetic, K.

    1991-03-11

    The authors used uretan narcose to implant constant magnets of 50 mT under the skin of rats in head region. The ECG was registrated in the next 6 hours. From it they found much slower heart beat which culminated in the first 105 minutes. After 6 weeks of continual exposure the heart beat of the exposed rats was still slower then in the controls. It is concluded that a chronical exposition to the constant magnetic field affected rats organisms and no regulatory mechanism could prevent it.

  20. Intracranial volume in craniosynostotic rabbits.

    PubMed

    Mooney, M P; Burrows, A M; Wigginton, W; Singhal, V K; Losken, H W; Smith, T D; Dechant, J; Towbin, A; Cooper, G M; Towbin, R; Siegel, M I

    1998-05-01

    Although craniosynostosis alters brain growth direction resulting in compensatory changes in the neurocranium, it has been suggested that such compensations occur with little reduction in intracranial volume (ICV). This hypothesis was tested in a rabbit model with nonsyndromic, familial coronal suture synostosis. Cross-sectional three-dimensional computed tomographic head scans were obtained from 79 rabbits (25 normal, 28 with delayed-onset synostosis, and 26 with early-onset synostosis) at 25, 42, and 126 days of age. Intracranial contents were reconstructed and indirect ICV was calculated. Results revealed that by 25 days of age the intracranial contents from early-onset synostosed rabbit skulls showed rostral (anterior) constrictions and a "beaten copper" morphology in the parietal and temporal regions compared with the other two groups. These deformities increased in severity with age. Quantitatively, ICV was significantly reduced (P < 0.05) by 7% in rabbits with early-onset synostosis compared with both control rabbits and rabbits with delayed-onset synostosis at 25 days of age. By 126 days of age, ICV in rabbits with synostosis was significantly reduced (p < 0.05) by 11% in early-onset synostosis and by 8% in delayed-onset synostosis compared with normal rabbits. Results suggest that in rabbits with uncorrected craniosynostosis, compensatory changes in the neurocranium were not adequate to allow normal expansion of the neurocapsular matrix. Further research is needed to determine if ICV reduction is correlated with cerebral atrophy or cerebral spinal fluid (i.e., ventricular or subarachnoid) space compression in this model. PMID:9693554

  1. Noradrenaline synthesis after sympathetic nerve activation in rat atria and its dependence on calcium but not CAM kinase II and protein kinases A or C.

    PubMed Central

    Kotsonis, P.; Binko, J.; Majewski, H.

    1996-01-01

    1. The biosynthesis of noradrenaline following sympathetic nerve activation was investigated in rat atria. In particular the time course of noradrenaline synthesis changes, the relationship of changes in synthesis to transmitter release and the possible roles of second messengers and protein kinases were examined. 2. Rat atria incubated with the precursor [3H]-tyrosine synthesized [3H]-noradrenaline. Synthesis was enhanced following pulsatile electrical field stimulation (3 Hz for 5 min) with the bulk of the increase occurring in the first 45 min after the commencement of electrical stimulation. In separate experiments rat atria were pre-incubated with [3H]-noradrenaline and the radioactive outflow in response to electrical field stimulation (3 Hz for 5 min) was taken as an index of noradrenaline release. 3. Stimulation-induced (S-I) noradrenaline synthesis was significantly correlated to S-I noradrenaline release for a variety of procedures which modulate noradrenaline release by mechanisms altering Ca2+ entry into the neurone (r2 = 0.99): those which decreased release: tetrodotoxin (0.3 microM), Ca(2+)-free medium, lowering the frequency of nerve activation to 1 Hz, and those which increased release, tetraethylammonium (0.3 mM), phentolamine (1 microM) and the combination of phentolamine (1 microM) and adenosine (10 microM). On the strength of this relationship we suggest that Ca2+ entry is a determining factor in S-I synthesis changes rather than the amount of noradrenaline released. Indeed the reduction in noradrenaline release with the calmodulin-dependent protein (CAM) kinase II inhibitor KN-62 (10 microM) which acts subsequent to Ca2+ entry, did not affect S-I synthesis. 4. The cell permeable cyclic AMP analogue, 8-bromoadenosine 3',5'-monophosphate (BrcAMP, 90 and 270 microM), dose-dependently increased basal [3H]-noradrenaline synthesis in unstimulated rat atria. This effect was antagonized by the selective protein kinase A (PKA) antagonist, Rp-8

  2. The effect of adenosine deaminase inhibition on the A1 adenosinergic and M2 muscarinergic control of contractility in eu- and hyperthyroid guinea pig atria.

    PubMed

    Pak, Krisztian; Zsuga, Judit; Kepes, Zita; Erdei, Tamas; Varga, Balazs; Juhasz, Bela; Szentmiklosi, Andras Jozsef; Gesztelyi, Rudolf

    2015-08-01

    The A1 adenosine and M2 muscarinic receptors exert protective (including energy consumption limiting) effects in the heart. We investigated the influence of adenosine deaminase (ADA) inhibition on a representative energy consumption limiting function, the direct negative inotropic effect elicited by the A1 adenosinergic and M2 muscarinergic systems, in eu- and hyperthyroid atria. Furthermore, we compared the change in the interstitial adenosine level caused by ADA inhibition and nucleoside transport blockade, two well-established processes to stimulate the cell surface A1 adenosine receptors, in both thyroid states. A classical isolated organ technique was applied supplemented with the receptorial responsiveness method (RRM), a concentration estimating procedure. Via measuring the contractile force, the direct negative inotropic capacity of N(6)-cyclopentyladenosine, a selective A1 receptor agonist, and methacholine, a muscarinic receptor agonist, was determined on the left atria isolated from 8-day solvent- and thyroxine-treated guinea pigs in the presence and absence of 2'-deoxycoformycin, a selective ADA inhibitor, and NBTI, a selective nucleoside transporter inhibitor. We found that ADA inhibition (but not nucleoside transport blockade) increased the signal amplification of the A1 adenosinergic (but not M2 muscarinergic) system. This action of ADA inhibition developed in both thyroid states, but it was greater in hyperthyroidism. Nevertheless, ADA inhibition produced a smaller rise in the interstitial adenosine concentration than nucleoside transport blockade did in both thyroid states. Our results indicate that ADA inhibition, besides increasing the interstitial adenosine level, intensifies the atrial A1 adenosinergic function in another (thyroid hormone-sensitive) way, suggesting a new mechanism of action of ADA inhibition. PMID:25877465

  3. Binding of two specific bradycardic agents, alinidine and AQ-A 39, to muscarinic receptors of guinea pig atria and ventricle.

    PubMed

    Brunner, F; Kukovetz, W R

    1988-02-01

    The mechanism of action of the two "specific bradycardic agents" alinidine and AQ-A 39 (falipamil) is still a matter of controversy. Their binding properties to atrial and ventricular myocardium of the guinea pig and rat were, therefore, investigated by the radioligand binding technique. In competition studies against the nonselective antagonists [125I]3-quinuclidinyl 4-iodobenzilate [( 125I]QNB) and 1-N-methyl-[3H]scopolamine methylchloride [( 3H]NMS), both alinidine and AQ-A 39 competitively displaced the radioligands with I50 values (corrected for radioligand concentration) of 1-2 microM (alinidine/[125I]QNB) and 4 microM (alinidine/[3H]NMS), respectively. The I50 values for AQ-A 39 were lower by a factor of two. Slope factors (pseudo Hill coefficients) were 0.7-0.8 (AQ-A 39) and 0.8-0.9 (alinidine), and significantly lower than unity in both atria and ventricle. The guanosine triphosphate (GTP) (100 microM) and 5'-guanylimido-di-phosphate [Gpp(NH)p] (100 microM) slightly creased [3H]QNB binding and produced no or only a small (factor 2-3) rightward shift of alinidine and AQ-A 39 competition curves. At high concentration (1 mM), AQ-A 39 drastically decreased [125I]QNB dissociation rate from both atrial and ventricular receptors (t1/2 control, 19 min; plus AQ-A 39, 75 min) while alinidine (1 mM) decreased dissociation half-life in ventricle with no change in atria. It is concluded that both bradycardic agents possess some but not all characteristics of weak agonists in binding studies, and that they also bind to an allosteric site of the muscarinic receptors. Association with this site could possibly activate a mixed Na+/K+ inward pacemaker current (if) resulting in bradycardia. PMID:2452318

  4. The cottontail rabbits of Virginia

    USGS Publications Warehouse

    Llewellyn, L.M.; Handley, C.O.

    1945-01-01

    Five races of cottontail rabbits belonging to three species occur in Virginia. One of them, the Mearns cottontail (Sylvilagus floridanus mearnsi), is reported here for the first time. It occurs in six southwestern counties of the state, while the eastern cottontail (S. f. mallurus) occurs in the remainder of the state with the exception of Smith and Fishermans islands off the eastern coast of Cape Charles, where it is replaced by Hitchens cottontail (S. f. hitchensi). The New England cottontail (S. transitionalis) is found on the higher mountain peaks, above 3000 feet, and the swamp rabbit (S. palustris) occurs in the Dismal Swamp region of southeastern Virginia.....The height of the breeding season for the eastern cottontail in Virginia is March and April, but breeding continues through the entire year except in December and January. The average litter size based on embryo counts was 4.7. The sex ratio of 234 specimens from all parts of the state, taken mostly in the December to February period, was 53 males to 47 females. That of a group of 145 rabbits live-trapped at Blacksburg during February and Marchwas 58 males to 42 females. The figures show that males are more active than females during the winter months, and therefore are more easily taken then....In transplanting cottontails from one section of the state to another, it is recommended that only cottontails of the same race as those originally present in the region being restocked be released there....Tularemia is not a common disease among rabbits in Virginia, but the rabbit ticks are often carriers of the disease and may transmit it to rabbits. Rabbit ticks are also found to be carriers of Rocky Mountain fever and American Q. fever. After the ticks drop off the rabbits to hibernate in the ground, which is likely to occur during mid-winter in Virginia, there is relatively little danger of humans contracting tularemia by contact with rabbits. Present laws in Virginia which prohibit rabbit hunting until the

  5. Editorial: Robust Detection of Heart Beats in Multimodal Data

    PubMed Central

    Silva, Ikaro; Moody, Benjamin; Behar, Joachim; Johnson, Alistair; Oster, Julien; Clifford, Gari D.; Moody, George B.

    2015-01-01

    This editorial reviews the background issues, the design, the key achievements, and the follow-up research generated as a result of the PhysioNet/Computing in Cardiology (CinC) 2014 Challenge, published in the concurrent special issue of Physiological Measurement. Our major focus was to accelerate the development and facilitate the comparison of robust methods for locating heart beats in long-term multi-channel recordings. A public (training) database consisting of 151,032 annotated beats was compiled from records that contained ECGs as well as pulsatile signals that directly reflect cardiac activity, and other signals that may have few or no observable markers of heart beats. A separate hidden test data set (consisting of 152,478 beats) is permanently stored at PhysioNet, and a public framework has been developed to provide researchers the ability to continue to automatically score and compare the performance of their algorithms. A scoring criteria based on the averaging of gross sensitivity, gross positive predictivity, average sensitivity, and average positive predictivity is proposed. The top three scores (as of March 2015) on the hidden test data set were 93.64%, 91.50%, and 90.70%. PMID:26217894

  6. Are African American Fraternities Beating Themselves to Death?

    ERIC Educational Resources Information Center

    Ruffins, Paul

    1997-01-01

    Beating of pledges, frequently leading to lawsuits and sometimes to death, has become a serious problem in black fraternities. Although black fraternities officially cracked down on hazing in 1990 in response to a student's death, many fear underground hazing has become even more dangerous. Incidents occur both on black and on white campuses.…

  7. Lung transplantation from the non-heart beating donor.

    PubMed

    Dark, John H

    2008-07-27

    The inflated lung, with its unique tolerance of the absence of a circulation, is particularly suited to retrieval from the non-heart beating donor. Absence of some of the squeal of brain death may be a further potential advantage. This concept has been embraced by several centers around the world, with promising early results. PMID:18645477

  8. Fertility Info Lacking for Young Women Who Beat Cancer

    MedlinePlus

    ... MedlinePlus Site Map FAQs Contact Us Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Latest Health News → Article URL of this page: https://www.nlm.nih.gov/medlineplus/news/fullstory_158989.html Fertility Info Lacking for Young Women Who Beat Cancer ...

  9. Using Science and Much More to Beat the Flood

    ERIC Educational Resources Information Center

    Seeley, Claire

    2014-01-01

    The Beat the Flood challenge involves designing and building a model flood-proof home, which is then tested in "flood" conditions. It is set on the fictitious Watu Island. The children form teams, with each team member being assigned a responsibility for the duration of the task--team leader, chief recorder, and resource manager. This…

  10. Phase Shifting and the Beating of Complex Waves

    ERIC Educational Resources Information Center

    Keeports, David

    2011-01-01

    At the introductory level, the demonstration and analysis of sound beating is usually limited to the superposition of two purely sinusoidal waves with equal amplitudes and very similar frequencies. Under such conditions, an observer hears the periodic variation of the loudness of a sound with an unchanging timbre. On the other hand, when complex…

  11. Perceptions of Conducting: Accuracy in Detecting Modulated Beat.

    ERIC Educational Resources Information Center

    Brittin, Ruth V.

    1992-01-01

    Presents findings of a study of viewers' ability to detect changes in conducting beat patterns. Reports that music education majors were significantly better able to detect tempo decreases than increases and better able than nonmajors to detect decreases. Indicates that nonmajors were better able than majors to identify tempo increases. (SG)

  12. Asynchronous beating of cilia enhances particle capture rate

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Kanso, Eva

    2014-11-01

    Many aquatic micro-organisms use beating cilia to generate feeding currents and capture particles in surrounding fluids. One of the capture strategies is to ``catch up'' with particles when a cilium is beating towards the overall flow direction (effective stroke) and intercept particles on the downstream side of the cilium. Here, we developed a 3D computational model of a cilia band with prescribed motion in a viscous fluid and calculated the trajectories of the particles with different sizes in the fluid. We found an optimal particle diameter that maximizes the capture rate. The flow field and particle motion indicate that the low capture rate of smaller particles is due to the laminar flow in the neighbor of the cilia, whereas larger particles have to move above the cilia tips to get advected downstream which decreases their capture rate. We then analyzed the effect of beating coordination between neighboring cilia on the capture rate. Interestingly, we found that asynchrony of the beating of the cilia can enhance the relative motion between a cilium and the particles near it and hence increase the capture rate.

  13. System-Beating: Structural Impediments to the Public Good.

    ERIC Educational Resources Information Center

    Rosner, Lydia S.

    1993-01-01

    Suggests that within bureaucratic systems norms of behavior develop that can be classified as system-beating. Examines elements necessary for such behavior to occur: individual with role within system; system comprised of many specific roles; observation of practical actions and practical circumstances; interpretation of these circumstances;…

  14. Beating HF waves to generate VLF waves in the ionosphere

    NASA Astrophysics Data System (ADS)

    Kuo, Spencer; Snyder, Arnold; Kossey, Paul; Chang, Chia-Lie; Labenski, John

    2012-03-01

    Beat-wave generation of very low frequency (VLF) waves by two HF heaters in the ionosphere is formulated theoretically and demonstrated experimentally. The heater-induced differential thermal pressure force and ponderomotive force, which dominate separately in the D and F regions of the ionosphere, drive an electron current for the VLF emission. A comparison, applying appropriate ionospheric parameters shows that the ponderomotive force dominates in beat-wave generation of VLF waves. Three experiments, one in the nighttime in the absence of D and E layers and two in the daytime in the presence of D and E layers, were performed. X mode HF heaters of slightly different frequencies were transmitted at CW full power. VLF waves at 10 frequencies ranging from 3.5 to 21.5 kHz were generated. The frequency dependencies of the daytime and nighttime radiation intensities are quite similar, but the nighttime radiation is much stronger than the daytime one at the same radiation frequency. The intensity ratio is as large as 9 dB at 11.5 kHz. An experiment directly comparing VLF waves generated by the beat-wave approach and by the amplitude modulation (AM) approach was also conducted. The results rule out the likely contribution of the AM mechanism acting on the electrojet and indicate that beat-wave in the VLF range prefers to be generated in the F region of the ionosphere through the ponderomotive nonlinearity, consistent with the theory. In the nighttime experiment, the ionosphere was underdense to the HF heaters, suggesting a likely setting for effective beat-wave generation of VLF waves by the HF heaters.

  15. Correlations in heart beat data as quantitative characterization of heart pathology

    SciTech Connect

    Ulbikas, J.; Cenys, A.; Zemaityte, D.; Varoneckas, G.

    1996-06-01

    Correlation between heart pathology and statistical properties of heart beat data has been studied. It is shown that heart beat data has different scaling behavior for healthy and disease cases. Possibilities to develop new monitoring technique based on the permanent control of the correlations in heart beat data are discussed. {copyright} {ital 1996 American Institute of Physics.}

  16. Bead-beating artefacts in the Bacteroidetes to Firmicutes ratio of the human stool metagenome.

    PubMed

    Vebø, Heidi C; Karlsson, Magdalena Kauczynska; Avershina, Ekaterina; Finnby, Lene; Rudi, Knut

    2016-10-01

    We evaluated bead-beating cell-lysis in analysing the human stool metagenome, since this is a key step. We observed that two different bead-beating instruments from the same producer gave a three-fold difference in the Bacteroidetes to Firmicutes ratio. This illustrates that bead-beating can have a major impact on downstream metagenome analyses. PMID:27498349

  17. Poor synchronization to the beat may result from deficient auditory-motor mapping.

    PubMed

    Sowiński, Jakub; Dalla Bella, Simone

    2013-08-01

    Moving to the beat of music is natural and spontaneous for humans. Yet some individuals, so-called 'beat deaf', may differ from the majority by being unable to synchronize their movements to musical beat. This condition was recently described in Mathieu (Phillips-Silver et al. (2011). Neuropsychologia, 49, 961-969), a beat-deaf individual, showing inaccurate motor synchronization to the beat accompanied by poor beat perception, with spared pitch processing. It has been suggested that beat deafness is the outcome of impoverished beat perception. Deficient synchronization to the beat, however, may also result from inaccurate mapping of the perceived beat to movement. To test this possibility, we asked 99 non-musicians to synchronize with musical and non-musical stimuli via hand tapping. Ten among them who revealed particularly poor synchronization were submitted to a thorough assessment of motor synchronization to various pacing stimuli and of beat perception. Four participants showed poor synchronization in absence of poor pitch perception; moreover, among them, two individuals were unable to synchronize to music, in spite of unimpaired detection of small durational deviations in musical and non-musical sequences, and normal rhythm discrimination. This mismatch of perception and action points toward disrupted auditory-motor mapping as the key impairment accounting for poor synchronization to the beat. PMID:23838002

  18. Use of seismocardiogram for the beat-to-beat assessment of the Pulse Transit Time: A pilot study.

    PubMed

    Di Rienzo, Marco; Vaini, Emanuele; Lombardi, Prospero

    2015-08-01

    We propose a new methodology for the estimation of Pulse Transit Time, PTT, based on the use of the seismocardiogram for the identification of the aortic valve opening, AO. This method has been implemented to obtain a first description of the AO-derived PTT beat-to-beat variability at rest and during the recovery after a cycloergometer exercise at 25W and 100W, its relation with systolic blood pressure, S(BP), and its difference with respect to variability of the Pulse Arrival Time, PAT (i.e. the BP transit time estimated by considering the ECG R peak instead of AO as proximal site). Our preliminary data indicate that 1) the fast components of the PTT variability are only marginally influenced by respiration; 2) only the slower components of the PTT variability are correlated with systolic BP; 3) major differences exist in the dynamics of PTT and PAT, being PAT variability significantly larger and importantly influenced by the beat-to-beat changes occurring in the Pre Ejection Period. PMID:26737949

  19. A review of beat-to-beat vectorcardiographic (VCG) parameters for analyzing repolarization variability in ECG signals.

    PubMed

    Hasan, Muhammad A; Abbott, Derek

    2016-02-01

    Elevated ventricular repolarization lability is believed to be linked to the risk of ventricular tachycardia/ventricular fibrillation. However, ventricular repolarization is a complex electrical phenomenon, and abnormalities in ventricular repolarization are not completely understood. To evaluate repolarization lability, vectorcardiography (VCG) is an alternative approach where the electrocardiographic (ECG) signal can be considered as possessing both magnitude and direction. Recent research has shown that VCG is advantageous over ECG signal analysis for identification of repolarization abnormality. One of the key reasons is that the VCG approach does not rely on exact identification of the T-wave offset, which improves the reproducibility of the VCG technique. However, beat-to-beat variability in VCG is an emerging area for the investigation of repolarization abnormality though not yet fully realized. Therefore, the purpose of this review is to explore the techniques, findings, and efficacy of beat-to-beat VCG parameters for analyzing repolarization lability, which may have potential utility for further study. PMID:25992510

  20. Left ventricular diastolic filling with an implantable ventricular assist device: beat to beat variability with overall improvement

    NASA Technical Reports Server (NTRS)

    Nakatani, S.; Thomas, J. D.; Vandervoort, P. M.; Zhou, J.; Greenberg, N. L.; Savage, R. M.; McCarthy, P. M.

    1997-01-01

    OBJECTIVES: We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling. BACKGROUND: Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance. METHODS: Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation. RESULTS: Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p < 0.01) and late filling velocity rising from 8 +/- 11 to 32 +/- 23 cm/s (p < 0.05), resulting in an increase in the late to early filling ratio from 0.13 +/- 0.18 to 0.59 +/- 0.38 (p < 0.01) and a rise in the atrial filling fraction from 8 +/- 10% to 26 +/- 17% (p < 0.01). The deceleration time (from 112 +/- 40 to 160 +/- 44 ms, p < 0.05) and the filling period corrected by the RR interval (from 39 +/- 8% to 54 +/- 10%, p < 0.005) were also significantly prolonged. In the computer model, asynchronous LV assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables. CONCLUSIONS: With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but

  1. The role of the Na+/Ca2+ exchanger, INa and ICaL in the genesis of dofetilide-induced torsades de pointes in isolated, AV-blocked rabbit hearts

    PubMed Central

    Farkas, Attila S; Makra, Péter; Csík, Norbert; Orosz, Szabolcs; Shattock, Michael J; Fülöp, Ferenc; Forster, Tamás; Csanády, Miklós; Papp, Julius Gy; Varró, András; Farkas, András

    2009-01-01

    Background and purpose: The Na+/Ca2+ exchanger (NCX) may contribute to triggered activity and transmural dispersion of repolarization, which are substrates of torsades de pointes (TdP) type arrhythmias. This study examined the effects of selective inhibition of the NCX by SEA0400 on the occurrence of dofetilide-induced TdP. Experimental approach: Effects of SEA0400 (1 µmol·L−1) on dofetilide-induced TdP was studied in isolated, Langendorff-perfused, atrioventricular (AV)-blocked rabbit hearts. To verify the relevance of the model, lidocaine (30 µmol·L−1) and verapamil (750 nmol·L−1) were also tested against dofetilide-induced TdP. Key results: Acute AV block caused a chaotic idioventricular rhythm and strikingly increased beat-to-beat variability of the RR and QT intervals. SEA0400 exaggerated the dofetilide-induced increase in the heart rate-corrected QT interval (QTc) and did not reduce the incidence of dofetilide-induced TdP [100% in the SEA0400 + dofetilide group vs. 75% in the dofetilide (100 nmol·L−1) control]. In the second set of experiments, verapamil further increased the dofetilide-induced QTc prolongation and neither verapamil nor lidocaine reduced the dofetilide-induced increase in the beat-to-beat variability of the QT interval. However, lidocaine decreased and verapamil prevented the development of dofetilide-induced TdP as compared with the dofetilide control (TdP incidence: 13%, 0% and 88% respectively). Conclusions and implications: Na+/Ca2+ exchanger does not contribute to dofetilide-induced TdP, whereas Na+ and Ca2+ channel activity is involved in TdP genesis in isolated, AV-blocked rabbit hearts. Neither QTc prolongation nor an increase in the beat-to-beat variability of the QT interval is a sufficient prerequisite of TdP genesis in rabbit hearts. PMID:19222480

  2. The impact of beat-to-beat variability in optimising the acute hemodynamic response in cardiac resynchronisation therapy

    PubMed Central

    Niederer, Steven; Walker, Cameron; Crozier, Andrew; Hyde, Eoin R.; Blazevic, Bojan; Behar, Jonathan M.; Claridge, Simon; Sohal, Manav; Shetty, Anoop; Jackson, Tom; Rinaldi, Christopher

    2015-01-01

    Background Acute indicators of response to cardiac resynchronisation therapy (CRT) are critical for developing lead optimisation algorithms and evaluating novel multi-polar, multi-lead and endocardial pacing protocols. Accounting for beat-to-beat variability in measures of acute haemodynamic response (AHR) may help clinicians understand the link between acute measurements of cardiac function and long term clinical outcome. Methods and results A retrospective study of invasive pressure tracings from 38 patients receiving an acute pacing and electrophysiological study was performed. 602 pacing protocols for left ventricle (LV) (n = 38), atria–ventricle (AV) (n = 9), ventricle–ventricle (VV) (n = 12) and endocardial (ENDO) (n = 8) optimisation were performed. AHR was measured as the maximal rate of LV pressure development (dP/dtMx) for each beat. The range of the 95% confidence interval (CI) of mean AHR was ~ 7% across all optimisation protocols compared with the reported CRT response cut off value of 10%. A single clear optimal protocol was identifiable in 61%, 22%, 25% and 50% for LV, AV, VV and ENDO optimisation cases, respectively. A level of service (LOS) optimisation that aimed to maximise the expected AHR 5th percentile, minimising variability and maximising AHR, led to distinct optimal protocols from conventional mean AHR optimisation in 34%, 78%, 67% and 12.5% of LV, AV, VV and ENDO optimisation cases, respectively. Conclusion The beat-to-beat variation in AHR is significant in the context of CRT cut off values. A LOS optimisation offers a novel index to identify the optimal pacing site that accounts for both the mean and variation of the baseline measurement and pacing protocol. PMID:26844303

  3. Influences of rapid pacing-induced electrical remodeling on pharmacological manipulation of the atrial refractoriness in rabbits.

    PubMed

    Chiba, Toshiki; Kondo, Naoto; Takahara, Akira

    2016-03-01

    Electrical remodeling plays a pivotal role in maintaining the reentry during atrial fibrillation. In this study, we assessed influence of electrical remodeling on pharmacological manipulation of the atrial refractoriness in rabbits. We used an atrial electrical remodeling model of the rabbit, subjected to rapid atrial pacing (RAP; 600 beats/min) for 2-4 weeks, leading to shortening of atrial effective refractory period (AERP). Intravenous administration of dl-sotalol (6 mg/kg), bepridil (1 mg/kg), amiodarone (10 mg/kg) or vernakalant (3 mg/kg) significantly prolonged the AERP both in the control and RAP rabbits. The extents in the RAP rabbits were similar to those in the control animals. On the other hand, prolonging effects of intravenously administered ranolazine (10 mg/kg) or tertiapin-Q (0.03 mg/kg) on the AERP in the RAP rabbits were more potent than those in the control animals. These results suggest that rapid pacing-induced electrical remodeling effectively modified the prolonging effects of ranolazine and tertiapin-Q on the AERP in contrast to those of clinically available antiarrhythmic drugs, dl-sotalol, bepridil amiodarone and vernakalant. PMID:27032905

  4. Rabbit model of rotavirus infection.

    PubMed Central

    Conner, M E; Estes, M K; Graham, D Y

    1988-01-01

    A new small animal model was developed to study parameters of rotavirus infections, including the active immune response. Seronegative New Zealand White rabbits (neonatal to 4 months old) were inoculated orally with cultivatable rabbit rotavirus strains Ala, C11, and R2 and with the heterologous simian strain SA11. The course of infection was evaluated by clinical findings, virus isolation (plaque assay and enzyme-linked immunosorbent assay), and serologic response. All four strains of virus were capable of infecting rabbits as determined by isolation of infectious virus from intestinal contents or fecal samples, by seroconversion, or by a combination of these methods. The responses differed depending on the virus strain used for inoculation. Rabbits remained susceptible to primary infection to at least 16 weeks of age (upper limit examined). Virus excretion in intestinal contents was detected from 6 h to 7 days postinoculation. RNA electropherotypes of inocula and viruses isolated from rabbits were the same in all samples tested. Transmission of Ala virus and R2 virus but not SA11 virus from inoculated animals to uninoculated controls also occurred. In a challenge experiment with Ala virus, 74- and 90-day-old rabbits were rechallenged with Ala 5 weeks after a primary infection with Ala. Virus was excreted in feces from 2 to 8 days after the primary infection but was not excreted after challenge. These results indicate that the rabbit provides an ideal model to investigate both the primary and secondary active immune responses to rotavirus infections and to evaluate candidate vaccines. Images PMID:2833612

  5. Recovery of spray paint traces from clothing by beating.

    PubMed

    Olderiks, Maurice; Baiker, Martin; van Velzen, Jill; van der Weerd, Jaap

    2015-03-01

    Manual recovery of spray paints from textiles using a microscope, the routine method in many laboratories, is often laborious. Beating the clothing with a plastic rod, the routine method used for recovery of glass traces within the authors' laboratory, is proposed as an alternative. The efficiency of the method was evaluated by spray tests with fluorescent paint. In these tests, paint particles in the acquired debris samples, as well as those remaining on the textiles, were investigated. The results show that beating is an efficient way to recover and concentrate paint particles. A good efficiency for jeans fabric and rough knitwear is reported. The results appeared to be less satisfactory for smooth woven fabric. Application of the method in casework was effective for graffiti paints as well as for flaked car paint. PMID:25482095

  6. Noise and Synchronization in Pairs of Beating Eukaryotic Flagella

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.; Polin, Marco; Tuval, Idan

    2009-10-01

    It has long been conjectured that hydrodynamic interactions between beating eukaryotic flagella underlie their ubiquitous forms of synchronization; yet there has been no experimental test of this connection. The biflagellate alga Chlamydomonas is a simple model for such studies, as its two flagella are representative of those most commonly found in eukaryotes. Using micromanipulation and high-speed imaging, we show that the flagella of a C. reinhardtii cell present periods of synchronization interrupted by phase slips. The dynamics of slips and the statistics of phase-locked intervals are consistent with a low-dimensional stochastic model of hydrodynamically coupled oscillators, with a noise amplitude set by the intrinsic fluctuations of single flagellar beats.

  7. Emergence of Synchronized Beating during the Regrowth of Eukaryotic Flagella

    NASA Astrophysics Data System (ADS)

    Goldstein, Raymond E.; Polin, Marco; Tuval, Idan

    2011-09-01

    A fundamental issue in the biology of eukaryotic flagella is the origin of synchronized beating observed in tissues and organisms containing multiple flagella. Recent studies of the biflagellate unicellular alga Chlamydomonas reinhardtii provided the first evidence that the interflagellar coupling responsible for synchronization is of hydrodynamic origin. To investigate this mechanism in detail, we study here synchronization in Chlamydomonas as its flagella slowly regrow after mechanically induced self-scission. The duration of synchronized intervals is found to be strongly dependent on flagellar length. Analysis within a stochastic model of coupled phase oscillators is used to extract the length dependence of the interflagellar coupling and the intrinsic beat frequencies of the two flagella. Physical and biological considerations that may explain these results are proposed.

  8. Cholinesterase activity and exposure time to acetylcholine as factors influencing the muscarinic inhibition of [3H]-noradrenaline overflow from guinea-pig isolated atria.

    PubMed Central

    Fuder, H.; Muscholl, E.; Wolf, K.

    1985-01-01

    Guinea-pig isolated atria were incubated and loaded with [3H]-noradrenaline. The release of 3H and of [3H]-noradrenaline was induced by field stimulation (6-9 trains of 150 pulses at 5 Hz). The stimulation-evoked overflows of 3H and of [3H]-noradrenaline were determined. In the absence of an inhibitor of acetylcholinesterase, acetylcholine (12 min preincubation before nerve stimulation, up to 10 microM) failed to inhibit the evoked [3H]-noradrenaline overflow. In the presence of atropine, an increase by acetylcholine of evoked release was observed in the same atria. In contrast, the selective muscarinic agonist methacholine significantly decreased the evoked overflow. The inhibition was antagonized by atropine. Methacholine did not enhance release in the presence of atropine. When present for only 2 min, acetylcholine 10 microM inhibited the evoked overflow and no facilitation of release was observed in the presence of atropine. In the presence of physostigmine, acetylcholine (12 min preincubation, 1 and 10 microM) inhibited evoked [3H]-noradrenaline overflow, but the overflow was increased by acetylcholine 10 microM in the presence of atropine. In the presence of cocaine, corticosterone, phentolamine, propranolol and hexamethonium together, acetylcholine 1 microM inhibited the evoked [3H]-noradrenaline overflow. The inhibition was significantly enhanced in the presence of physostigmine. It decreased with preincubation time of the agonist, despite the presence of physostigmine and constant replacement by new drug. Neither inhibition nor facilitation of evoked release was observed in the presence of atropine. It is concluded that a muscarinic inhibition by acetylcholine (upon prolonged exposure time) may be masked by a concomitant facilitation of release and/or desensitization of the muscarinic inhibitory mechanism. Furthermore, degradation by acetylcholinesterase contributes in part to the ineffectiveness of acetylcholine as a presynaptic inhibitor. When a

  9. Down beat nystagmus in vitamin B 12 deficiency syndrome.

    PubMed

    Puri, V; Chaudhry, N; Satyawani, M

    2006-01-01

    A 34 years old male, presenting with progressive proximal weakness, with a neurogenic pattern on needle EMG, and a family history suggestive of an autosomal recessive disorder, was found to have additional features of myeloneuropathy and a down beat nystagmus. A low serum vitamin B12 level was found, and on vitamin B12 supplementation there was a partial clinical as well as electrophysiological recovery. PMID:16795999

  10. Wave and particle dynamics of the beat-wave accelerator

    SciTech Connect

    Gibbon, P. )

    1989-10-15

    We present two-dimensional wave-envelope studies of the interaction between a plasma beat-wave and the laser pumps which drive it. A new method of focusing is demonstrated which requires the plasma wave to be driven slightly below its resonant frequency. Test particles are employed to investigate possible means of extending the accelerator stage length. {copyright} 1989 American Institute of Physics

  11. Teratology studies in the rabbit.

    PubMed

    Allais, Linda; Reynaud, Lucie

    2013-01-01

    The rabbit is generally the non-rodent species or second species after the rat recommended by the regulatory authorities and is part of the package of regulatory reproductive studies for the detection of potential embryotoxic and/or teratogenic effects of pharmaceuticals, chemicals, food additives, and other compounds, including vaccines (see Chapters 1-7).Its availability, practicality in housing and in mating as well as its large size makes the rabbit the preferred choice as a non-rodent species. The study protocols are essentially similar to those established for the rat (Chapter 9), with some particularities. The study designs are well defined in guidelines and are relatively standardized between testing laboratories across the world.As for the rat, large litter sizes and extensive background data in the rabbit are valuable criteria for an optimal assessment of in utero development of the embryo or fetus and for the detection of potential external or internal fetal malformations. PMID:23138902

  12. Differential Fault Analysis of Rabbit

    NASA Astrophysics Data System (ADS)

    Kircanski, Aleksandar; Youssef, Amr M.

    Rabbit is a high speed scalable stream cipher with 128-bit key and a 64-bit initialization vector. It has passed all three stages of the ECRYPT stream cipher project and is a member of eSTREAM software portfolio. In this paper, we present a practical fault analysis attack on Rabbit. The fault model in which we analyze the cipher is the one in which the attacker is assumed to be able to fault a random bit of the internal state of the cipher but cannot control the exact location of injected faults. Our attack requires around 128 - 256 faults, precomputed table of size 241.6 bytes and recovers the complete internal state of Rabbit in about 238 steps.

  13. Calcium antagonist property of CPU228, a dofetilide derivative, contributes to its low incidence of torsades de pointes in rabbits.

    PubMed

    Huang, Zhi-Jiang; Dai, De-Zai; Li, Na; Na, Tao; Ji, Min; Dai, Yin

    2007-04-01

    1. Torsades de pointes (TDP) is a severe adverse effect during the clinical use of dofetilide, a selective blocker of the rapid component of the delayed rectifier potassium channel (I(Kr)). The present study was designed to test whether CPU228, a derivative of dofetilide with calcium (Ca(2+)) antagonist properties, could reduce TDP without reducing the blockade of I(Kr). 2. The incidence of TDP in a rabbit model and the effective refractory period (ERP) were measured and compared for dofetilide and CPU228. Suppression of I(Kr) and the L-type Ca(2+) current (I(Ca,L)) and the Ca(2+) transients of isolated cardiomyocytes were investigated by whole-cell patch-clamp and Fluo-3 dye spectrophotometry. 3. The incidence of TDP was greatly reduced by CPU228 relative to dofetilide, occurring in only one of six rabbits compared with five of six rabbits following dofetilide (P < 0.05). In isolated atria, prolongation of ERP by CPU228 was less than that of dofetilide and no reverse frequency dependence was observed. Negative inotropism by CPU228 was significant against positive inotropism by dofetilide. CPU228 inhibited both I(Kr) and I(Ca,L) currents and the IC(50) for I(Ca,L) inhibition was 0.909 micromol/L. At 3 micromol/L, CPU228 significantly suppressed the Ca(2+) transients. 4. CPU228 is able to block I(Ca,L), contributing to decreased TDP, while also blocking I(Kr) activity. By combined blockade of I(Kr) and I(Ca,L), CPU228 shares the property of complex Class III anti-arrhythmic agents. PMID:17324143

  14. Moving to the Beat and Singing are Linked in Humans.

    PubMed

    Dalla Bella, Simone; Berkowska, Magdalena; Sowiński, Jakub

    2015-01-01

    The abilities to sing and to move to the beat of a rhythmic auditory stimulus emerge early during development, and both engage perceptual, motor, and sensorimotor processes. These similarities between singing and synchronization to a beat may be rooted in biology. Patel (2008) has suggested that motor synchronization to auditory rhythms may have emerged during evolution as a byproduct of selection for vocal learning ("vocal learning and synchronization hypothesis"). This view predicts a strong link between vocal performance and synchronization skills in humans. Here, we tested this prediction by asking occasional singers to tap along with auditory pulse trains and to imitate familiar melodies. Both vocal imitation and synchronization skills were measured in terms of accuracy and precision or consistency. Accurate and precise singers tapped more in the vicinity of the pacing stimuli (i.e., they were more accurate) than less accurate and less precise singers. Moreover, accurate singers were more consistent when tapping to the beat. These differences cannot be ascribed to basic motor skills or to motivational factors. Individual differences in terms of singing proficiency and synchronization skills may reflect the variability of a shared sensorimotor translation mechanism. PMID:26733370

  15. Analysis of the ciliary/flagellar beating of Chlamydomonas.

    PubMed

    Foster, Kenneth W

    2009-01-01

    Eukaryotic flagella and cilia are alternative names, for the slender cylindrical protrusions of a cell (240nm diameter, approximately 12,800nm-long in Chlamydomonas reinhardtii) that propel a cell or move fluid. Cilia are extraordinarily successful complex organelles abundantly found in animals performing many tasks. They play a direct or developmental role in the sensors of fluid flow, light, sound, gravity, smells, touch, temperature, and taste in mammals. The failure of cilia can lead to hydrocephalus, infertility, and blindness. However, in spite of their large role in human function and pathology, there is as yet no consensus on how cilia beat and perform their many functions, such as moving fluids in brain ventricles and lungs and propelling and steering sperm, larvae, and many microorganisms. One needs to understand and analyze ciliary beating and its hydrodynamic interactions. This chapter provides a guide for measuring, analyzing, and interpreting ciliary behavior in various contexts studied in the model system of Chlamydomonas. It describes: (1) how cilia work as self-organized beating structures (SOBSs), (2) the overlaid control in the cilia that optimizes the SOBS to achieve cell dispersal, phototaxis steering, and avoidance of obstacles, (3) the assay of a model intracellular signal processing system that responds to multiple external and internal inputs, choosing mode of behavior and then controlling the cilia, (4) how cilia sense their environment, and (5) potentially an assay of ciliary performance for toxicology or medical assessment. PMID:20409788

  16. The blood beat measurement with near infrared ray

    NASA Astrophysics Data System (ADS)

    Oshiro, Osamu; Horio, Hideyuki; Masuda, Yasushi

    This paper describes the blood beat measurement system with near infra-red ray. A blood vessel was captured sequentially with a CCD camera, an near infra-red LED and an optical filter. In order to extract a blood vessel portion from each captured image, binarization processing was performed using the threshold on the basis of the first captured image. For the reduction of the error caused by the subject's hand slight movement, the position adjustment was performed with the landmark, which was found with skeltonizing and extracting the diverging point. The pixel number of the blood vessel portion was counted and the thickness of the blood vessel was analyzed by performing a Fourier analysis. The Fourier analysis shows the peak at the frequency of 1.4 Hz corresponding to 84 beat count in a minute. For the evaluation of the proposed method, blood beat was measured with a sphygmomanometer simultaneously. As the results, the almost same pulse rate could be obtained from both method. These results indicate that the method has the possibility to count a pulse.

  17. Laser precision ranger based on beat-wave interferometry

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Wu, Yanhua; Weia, Huang

    2008-10-01

    This paper presents a laser precision ranger based on beat wave interferometry. A frequency-stabilized double longitudinal modes He-Ne laser with thermoregulation is used as the light source. The two beams of double longitudinal modes generated in the same resonator of the laser are naturally coaxial. They have a frequency difference of about 790MHz and a beat wavelength of 380mm. Their stability is the same as the laser, which is better than 10-7 in open air. The node of the beat wave is used as the sampling flag. An adaptive filter and a wavelet transform program are used to eliminate the noise and to improve the accuracy of node detection. The distance between the node and the measur ed point is measured with a double frequency interferometer, which is incorporated in the same optical system and has a resolution of 0.08μm. Experimental results indicate that the measuring range is 20m and the uncertainty 30μm /10m.

  18. Moving to the Beat and Singing are Linked in Humans

    PubMed Central

    Dalla Bella, Simone; Berkowska, Magdalena; Sowiński, Jakub

    2015-01-01

    The abilities to sing and to move to the beat of a rhythmic auditory stimulus emerge early during development, and both engage perceptual, motor, and sensorimotor processes. These similarities between singing and synchronization to a beat may be rooted in biology. Patel (2008) has suggested that motor synchronization to auditory rhythms may have emerged during evolution as a byproduct of selection for vocal learning (“vocal learning and synchronization hypothesis”). This view predicts a strong link between vocal performance and synchronization skills in humans. Here, we tested this prediction by asking occasional singers to tap along with auditory pulse trains and to imitate familiar melodies. Both vocal imitation and synchronization skills were measured in terms of accuracy and precision or consistency. Accurate and precise singers tapped more in the vicinity of the pacing stimuli (i.e., they were more accurate) than less accurate and less precise singers. Moreover, accurate singers were more consistent when tapping to the beat. These differences cannot be ascribed to basic motor skills or to motivational factors. Individual differences in terms of singing proficiency and synchronization skills may reflect the variability of a shared sensorimotor translation mechanism. PMID:26733370

  19. European Rabbits as Reservoir for Coxiella burnetii

    PubMed Central

    González-Barrio, David; Maio, Elisa; Vieira-Pinto, Madalena

    2015-01-01

    We studied the role of European rabbits (Oryctolagus cuniculus) as a reservoir for Coxiella burnetii in the Iberian region. High individual and population seroprevalences observed in wild and farmed rabbits, evidence of systemic infections, and vaginal shedding support the reservoir role of the European rabbit for C. burnetii. PMID:25988670

  20. Osteoblastic Osteosarcoma in a Rabbit

    PubMed Central

    Ishikawa, Megumi; Kondo, Hirotaka; Onuma, Mamoru; Shibuya, Hisashi; Sato, Tsuneo

    2012-01-01

    An osteosarcoma developed in the tarsal joint region involving the distal tibia of a domestic rabbit (Oryctolagus cuniculus). Micrometastases were present in the lungs. Histologically the tumor was composed of ovoid to short-spindle cells with abundant giant cells, producing irregular islands of osteoids. The tumor cells were immunopositive with antiosteocalcin monoclonal antibody, consistent with their derivation from osteoblasts. According to review of 10 published cases, productive osteoblasic osteosarcoma is the most common bone tumor in rabbits, with half of all cases developing in the skull or facial bones. PMID:22546918

  1. Experimental infection of young rabbits with a rabbit enteric coronavirus.

    PubMed Central

    Descôteaux, J P; Lussier, G

    1990-01-01

    The clinical signs and lesions caused by the rabbit enteric coronavirus (RECV) were studied in young rabbits orally inoculated with a suspension containing RECV particles. The inoculated animals were observed daily for evidence of diarrhea. Fecal samples and specimens from the small intestine and from the gut associated lymphoid tissue (GALT) were collected from 2 h to 29 days postinoculation (PI) and processed for immune electron microscopy (IEM) and light microscopy. Coronavirus particles were detected in the cecal contents of most inoculated animals from 6 h to 29 days PI. Lesions were first observed 6 h PI and were characterized by a loss of the brush border of mature enterocytes located at the tips of intestinal villi and by necrosis of these cells. At 48 h PI, short intestinal villi and hypertrophic crypts were noted. In the GALT, complete necrosis of the M cells as well as necrosis of the enterocytes lining the villi above the lymphoid follicules with hypertrophy of the corresponding crypts were observed in all the animals. Five inoculated rabbits had diarrhea three days PI. The presence of RECV particles in the feces of the sick animals and the microscopic lesions observed in the small intestine suggested that the virus was responsible for the clinical signs. A few inoculated rabbits remained free of diarrhea. Fecal material collected at postmortem examination contained RECV particles. The results suggest that the virus could also produce a subclinical infection. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:2174299

  2. The mechanism of self-organized beating of cilia

    NASA Astrophysics Data System (ADS)

    Vidyadharan, Jyothish Sulochana

    The internal structure and physical properties of cilia are well known. The relevant hydrodynamics is also well known. But the mechanism behind the coordinated activity of the dynein molecular motors is not known. Based on experimental observations, it has been concluded that this mechanism cannot be due to control from the cell body. The possible mechanism has to be self-organized and the trigger for motor activation/deactivation has to be something related to the geometry of the ciliary axoneme. This thesis critically evaluates the most widely currently cited models and suggests an alternative model for how cilia beat. From the literature we obtained wave forms of ciliary beating at different instants in the beat cycle. These instants were digitized and interpolated. From this data, we were able to calculate the hydrodynamic force distribution (external force distribution) on the cilia and the translational and rotational velocities of the cell body. Once the hydrodynamic force distribution was obtained, we calculated the internal force distribution in the cilium using an equation we derived. Once this was known, we were able to calculate parameters of the ciliary axoneme such as the dynamic stiffness. The stiffness is the ratio of the first Fourier modes of the internal force distribution and the relative sliding between the doublet microtubules that form the axoneme. We found that the first mode was the dominant one and is the one we used for calculations. We were also able to calculate the energy involved in formation and propagation of the wave that produces the ciliary beating. We discovered that the dynamic stiffness varies along the length of a cilium. We determined that in the central region of the cilium, the stiffness is almost purely imaginary which means that the sliding velocity follows the internal force generation in that region rather than sliding. We also found that in Fourier space, the flexural rigidity (kappa=EI where E is Young's modulus and

  3. Prostanoid Receptors Involved in Regulation of the Beating Rate of Neonatal Rat Cardiomyocytes

    PubMed Central

    Mechiche, Hakima; Grassin-Delyle, Stanislas; Robinet, Arnaud; Nazeyrollas, Pierre; Devillier, Philippe

    2012-01-01

    Although prostanoids are known to be involved in regulation of the spontaneous beating rate of cultured neonatal rat cardiomyocytes, the various subtypes of prostanoid receptors have not been investigated in detail. In our experiments, prostaglandin (PG)F2α and prostanoid FP receptor agonists (fluprostenol, latanoprost and cloprostenol) produced a decrease in the beating rate. Two prostanoid IP receptor agonists (iloprost and beraprost) induced first a marked drop in the beating rate and then definitive abrogation of beating. In contrast, the prostanoid DP receptor agonists (PGD2 and BW245C) and TP receptor agonists (U-46619) produced increases in the beating rate. Sulprostone (a prostanoid EP1 and EP3 receptor agonist) induced marked increases in the beating rate, which were suppressed by SC-19220 (a selective prostanoid EP1 antagonist). Butaprost (a selective prostanoid EP2 receptor agonist), misoprostol (a prostanoid EP2 and EP3 receptor agonist), 11-deoxy-PGE1 (a prostanoid EP2, EP3 and EP4 receptor agonist) did not alter the beating rate. Our results strongly suggest that prostanoid EP1 receptors are involved in positive regulation of the beating rate. Prostanoid EP1 receptor expression was confirmed by western blotting with a selective antibody. Hence, neonatal rat cardiomyocytes express both prostanoid IP and FP receptors (which negatively regulate the spontaneous beating rate) and prostanoid TP, DP1 and EP1 receptors (which positively regulate the spontaneous beating rate). PMID:22984630

  4. Factors associated with wife beating in Egypt: Analysis of two surveys (1995 and 2005)

    PubMed Central

    Akmatov, Manas K; Mikolajczyk, Rafael T; Labeeb, Shokria; Dhaher, Enas; Khan, Md Mobarak

    2008-01-01

    Background Wife beating is an important public health problem in many developing countries. We assessed the rates of wife beating and examined factors associated with wife beating in 1995 and 2005 in Egypt. Methods We used data from two Demographic and Health Surveys (DHS) conducted in Egypt in 1995 and 2005 using multistage household sampling. Data related to wife beating included information from 7122 women in 1995 and 5612 women in 2005. Logistic regression was used to analyze factors independently associated with wife beating. Special weights were used to obtain nationally representative estimates. Results In 1995 17.5% of married women in Egypt experienced wife beating in the last 12 months, in 2005 – 18.9% or 16.0%, using different measures. The association between socio-demographic differentials and wife beating was weaker in the newer survey. The 12-month prevalence of wife beating was lower only when both partners were educated, but the differences across education levels were less pronounced in 2005. Based on the information available in the 2005 survey, more educated women experienced less severe forms of wife beating than less educated women. Conclusion Different measures used in both surveys make a direct comparison difficult. The observed patterns indicate that the changes in prevalence may be masked by two opposite processes occurring in the society: a decrease in (severe forms of) wife beating and an increase in reporting of wife beating. Improving the access to education for women and raising education levels in the whole society may help reducing wife beating. PMID:18801155

  5. Gain enhancement plasma-loaded FEL in the presence of beat waves

    SciTech Connect

    Shamamian, A.H.; Gevorgian, L.A.

    1995-12-31

    An expression for the dielectric permittivity of underdense plasma interacting with laser beat waves is derived. It is shown that the presence of beat waves in plasma results in an effective growth of the plasma frequency. The FEL Gain is investigated in the case when the frequency of soft photons weakly depending on the electron beam energy and the synchronism condition is maintained. It is shown that the plasma beat waves lead to the essential increase in FEL gain.

  6. Individual differences in beat perception affect gait responses to low- and high-groove music.

    PubMed

    Leow, Li-Ann; Parrott, Taylor; Grahn, Jessica A

    2014-01-01

    Slowed gait in patients with Parkinson's disease (PD) can be improved when patients synchronize footsteps to isochronous metronome cues, but limited retention of such improvements suggest that permanent cueing regimes are needed for long-term improvements. If so, music might make permanent cueing regimes more pleasant, improving adherence; however, music cueing requires patients to synchronize movements to the "beat," which might be difficult for patients with PD who tend to show weak beat perception. One solution may be to use high-groove music, which has high beat salience that may facilitate synchronization, and affective properties, which may improve motivation to move. As a first step to understanding how beat perception affects gait in complex neurological disorders, we examined how beat perception ability affected gait in neurotypical adults. Synchronization performance and gait parameters were assessed as healthy young adults with strong or weak beat perception synchronized to low-groove music, high-groove music, and metronome cues. High-groove music was predicted to elicit better synchronization than low-groove music, due to its higher beat salience. Two musical tempi, or rates, were used: (1) preferred tempo: beat rate matched to preferred step rate and (2) faster tempo: beat rate adjusted to 22.5% faster than preferred step rate. For both strong and weak beat-perceivers, synchronization performance was best with metronome cues, followed by high-groove music, and worst with low-groove music. In addition, high-groove music elicited longer and faster steps than low-groove music, both at preferred tempo and at faster tempo. Low-groove music was particularly detrimental to gait in weak beat-perceivers, who showed slower and shorter steps compared to uncued walking. The findings show that individual differences in beat perception affect gait when synchronizing footsteps to music, and have implications for using music in gait rehabilitation. PMID:25374521

  7. Individual Differences in Beat Perception Affect Gait Responses to Low- and High-Groove Music

    PubMed Central

    Leow, Li-Ann; Parrott, Taylor; Grahn, Jessica A.

    2014-01-01

    Slowed gait in patients with Parkinson’s disease (PD) can be improved when patients synchronize footsteps to isochronous metronome cues, but limited retention of such improvements suggest that permanent cueing regimes are needed for long-term improvements. If so, music might make permanent cueing regimes more pleasant, improving adherence; however, music cueing requires patients to synchronize movements to the “beat,” which might be difficult for patients with PD who tend to show weak beat perception. One solution may be to use high-groove music, which has high beat salience that may facilitate synchronization, and affective properties, which may improve motivation to move. As a first step to understanding how beat perception affects gait in complex neurological disorders, we examined how beat perception ability affected gait in neurotypical adults. Synchronization performance and gait parameters were assessed as healthy young adults with strong or weak beat perception synchronized to low-groove music, high-groove music, and metronome cues. High-groove music was predicted to elicit better synchronization than low-groove music, due to its higher beat salience. Two musical tempi, or rates, were used: (1) preferred tempo: beat rate matched to preferred step rate and (2) faster tempo: beat rate adjusted to 22.5% faster than preferred step rate. For both strong and weak beat-perceivers, synchronization performance was best with metronome cues, followed by high-groove music, and worst with low-groove music. In addition, high-groove music elicited longer and faster steps than low-groove music, both at preferred tempo and at faster tempo. Low-groove music was particularly detrimental to gait in weak beat-perceivers, who showed slower and shorter steps compared to uncued walking. The findings show that individual differences in beat perception affect gait when synchronizing footsteps to music, and have implications for using music in gait rehabilitation. PMID:25374521

  8. Photoacoustic tomography: Ultrasonically beating optical diffusion and diffraction

    NASA Astrophysics Data System (ADS)

    Wang, Lihong

    2014-03-01

    A decade of research has pushed photoacoustic computed tomography to the forefront of molecular-level imaging, notes SPIE Fellow Lihong Wang (Washington University, St. Louis) in his plenary talk, "Photoacoustic Tomography: Ultrasonically Beating Optical Diffusion and Diffraction." Modern optical microscopy has resolution and diffraction limitations. But noninvasive functional photoacoustic computed tomography has overcome this limit, offering deep penetration with optical contrast and ultrasonic resolution of 1 cm depth or more -- up to 7 cm of penetration in some cases, such as evaluating sentinel lymph nodes for breast cancer staging. This opens up applications in whole body imaging, brain function, oxygen saturation, label-free cell analysis, and noninvasive cancer biopsies.

  9. Modulation of Attosecond Beating by Resonant Two-Photon Transition

    NASA Astrophysics Data System (ADS)

    Jiménez Galán, Álvaro; Argenti, Luca; Martín, Fernando

    2015-09-01

    We present an analytical model that characterizes two-photon transitions in the presence of autoionising states. We applied this model to interpret resonant RABITT spectra, and show that, as a harmonic traverses a resonance, the phase of the sideband beating significantly varies with photon energy. This phase variation is generally very different from the π jump observed in previous works, in which the direct path contribution was negligible. We illustrate the possible phase profiles arising in resonant two-photon transitions with an intuitive geometrical representation.

  10. Cascade focusing in the beat-wave accelerator

    SciTech Connect

    Gibbon, P.; Bell, A.R.

    1988-10-03

    The 2D wave-envelope equationf for the beat-wave--cascade system are studied analytically and numerically. An expression for the mean square width of the cascade envelope is obtained, and is used to predict the long-term behavior of the waves. The amplitude or a resonantly driven plasma wave falls significantly over a stage length due to enhanced diffraction of the cascade envelope. Conversely, detuning the pumps from the plasma frequency can lead to focusing of the envelope and a corresponding increase in plasmon amplitude of up to 200% over the same distance.

  11. Beating of Coupled Ultraviolet Light Modes in Zinc Oxide Nanoresonators

    NASA Astrophysics Data System (ADS)

    Schirra, M.; Feneberg, M.; Prinz, G. M.; Reiser, A.; Röder, T.; Thonke, K.; Sauer, R.

    2009-02-01

    Periodic spatial intensity modulations of near-band-gap luminescence light at 3.36 eV photon energy are reported in nanometer-sized resonators of single zinc oxide nanorods. These modulations are observed when the luminescence light, due to excitonic recombination, is excited by a focused low-energy electron beam scanned along the rods. The acceleration energy of only 2 keV allows for a spatial resolution of a few ten nanometers. Numerical calculations based on the theory of dielectric cylindrical waveguides are performed identifying the intensity modulations as beating patterns of coupled TE01 and TM01 modes in the nanoresonator.

  12. Regulatory pathways for the stimulation of canine tracheal ciliary beat frequency by bradykinin.

    PubMed Central

    Wong, L B; Miller, I F; Yeates, D B

    1990-01-01

    1. The effects of bradykinin, a potent inflammatory nanopeptide, on tracheal ciliary beat frequency in vivo were investigated using barbiturate-anaesthetized beagles. Tracheal ciliary beat frequency was measured using heterodyne mode correlation analysis laser light scattering, a technique that does not require surgical intervention. 2. Aerosolized 10(-5) M-bradykinin in 0.9% saline administered for 3 min to eight barbiturate-anaesthetized beagles stimulated tracheal ciliary beat frequency from the baseline of 5.3 +/- 0.1 Hz to a maximum of 16.6 +/- 2.0 Hz, 8 min after aerosol delivery, and ciliary beat frequency remained above baseline for the following 35 min. 3. Intravenously injected hexamethonium bromide, ipratropium bromide or indomethacin did not change baseline tracheal ciliary beat frequency. That down-regulation of ciliary beat frequency below baseline values was not observed with either the neural or the cyclooxygenase blocking agents suggests that neither of these pathways is involved in the maintenance of the observed basal ciliary beat frequency. 4. Bradykinin-induced stimulation of tracheal ciliary beat frequency is blocked by hexamethonium bromide, ipratropium bromide or indomethacin. These data suggest that the stimulation of ciliary beat frequency by bradykinin acts through both cellular cyclooxygenase and parasympathetic pathways in series. PMID:1972192

  13. Enhanced timing abilities in percussionists generalize to rhythms without a musical beat.

    PubMed

    Cameron, Daniel J; Grahn, Jessica A

    2014-01-01

    The ability to entrain movements to music is arguably universal, but it is unclear how specialized training may influence this. Previous research suggests that percussionists have superior temporal precision in perception and production tasks. Such superiority may be limited to temporal sequences that resemble real music or, alternatively, may generalize to musically implausible sequences. To test this, percussionists and nonpercussionists completed two tasks that used rhythmic sequences varying in musical plausibility. In the beat tapping task, participants tapped with the beat of a rhythmic sequence over 3 stages: finding the beat (as an initial sequence played), continuation of the beat (as a second sequence was introduced and played simultaneously), and switching to a second beat (the initial sequence finished, leaving only the second). The meters of the two sequences were either congruent or incongruent, as were their tempi (minimum inter-onset intervals). In the rhythm reproduction task, participants reproduced rhythms of four types, ranging from high to low musical plausibility: Metric simple rhythms induced a strong sense of the beat, metric complex rhythms induced a weaker sense of the beat, nonmetric rhythms had no beat, and jittered nonmetric rhythms also had no beat as well as low temporal predictability. For both tasks, percussionists performed more accurately than nonpercussionists. In addition, both groups were better with musically plausible than implausible conditions. Overall, the percussionists' superior abilities to entrain to, and reproduce, rhythms generalized to musically implausible sequences. PMID:25540617

  14. Enhanced timing abilities in percussionists generalize to rhythms without a musical beat

    PubMed Central

    Cameron, Daniel J.; Grahn, Jessica A.

    2014-01-01

    The ability to entrain movements to music is arguably universal, but it is unclear how specialized training may influence this. Previous research suggests that percussionists have superior temporal precision in perception and production tasks. Such superiority may be limited to temporal sequences that resemble real music or, alternatively, may generalize to musically implausible sequences. To test this, percussionists and nonpercussionists completed two tasks that used rhythmic sequences varying in musical plausibility. In the beat tapping task, participants tapped with the beat of a rhythmic sequence over 3 stages: finding the beat (as an initial sequence played), continuation of the beat (as a second sequence was introduced and played simultaneously), and switching to a second beat (the initial sequence finished, leaving only the second). The meters of the two sequences were either congruent or incongruent, as were their tempi (minimum inter-onset intervals). In the rhythm reproduction task, participants reproduced rhythms of four types, ranging from high to low musical plausibility: Metric simple rhythms induced a strong sense of the beat, metric complex rhythms induced a weaker sense of the beat, nonmetric rhythms had no beat, and jittered nonmetric rhythms also had no beat as well as low temporal predictability. For both tasks, percussionists performed more accurately than nonpercussionists. In addition, both groups were better with musically plausible than implausible conditions. Overall, the percussionists' superior abilities to entrain to, and reproduce, rhythms generalized to musically implausible sequences. PMID:25540617

  15. Capturing with EEG the neural entrainment and coupling underlying sensorimotor synchronization to the beat.

    PubMed

    Nozaradan, Sylvie; Zerouali, Younes; Peretz, Isabelle; Mouraux, André

    2015-03-01

    Synchronizing movements with rhythmic inputs requires tight coupling of sensory and motor neural processes. Here, using a novel approach based on the recording of steady-state-evoked potentials (SS-EPs), we examine how distant brain areas supporting these processes coordinate their dynamics. The electroencephalogram was recorded while subjects listened to a 2.4-Hz auditory beat and tapped their hand on every second beat. When subjects tapped to the beat, the EEG was characterized by a 2.4-Hz SS-EP compatible with beat-related entrainment and a 1.2-Hz SS-EP compatible with movement-related entrainment, based on the results of source analysis. Most importantly, when compared with passive listening of the beat, we found evidence suggesting an interaction between sensory- and motor-related activities when subjects tapped to the beat, in the form of (1) additional SS-EP appearing at 3.6 Hz, compatible with a nonlinear product of sensorimotor integration; (2) phase coupling of beat- and movement-related activities; and (3) selective enhancement of beat-related activities over the hemisphere contralateral to the tapping, suggesting a top-down effect of movement-related activities on auditory beat processing. Taken together, our results are compatible with the view that rhythmic sensorimotor synchronization is supported by a dynamic coupling of sensory and motor related activities. PMID:24108804

  16. On-Pump Beating Heart Extraanatomical Ascending-Descending Aortic Bypass Using a Beating Heart Positioner in an Adult with Aortic Coarctation

    PubMed Central

    Gyoten, Takayuki; Nagura, Saori; Yamashita, Akio; Fukahara, Kazuaki; Kotoh, Keiju; Yoshimura, Naoki

    2016-01-01

    The prognosis of uncorrected aortic coarctation is poor due to development of heart failure. We performed an on-pump beating heart extraanatomical ascending-descending aortic bypass using a beating heart positioner in an adult with coarctation complicated by severe left ventricular hypertrophy. A 51-year-old woman was referred with severe hypertension. Computed tomography demonstrated severe distal aortic arch narrowing. Coarctation of the aorta was diagnosed. A posterior pericardial beating heart extraanatomical bypass via median sternotomy was performed from the ascending to descending aorta using a heart positioner. Her postoperative course was uneventful and blood pressure was normal on a low-dose beta-blocker. PMID:27087874

  17. Lack of effect of chronic calcium antagonist treatment on beta 1- and beta 2-adrenoceptors in right atria from patients with or without heart failure.

    PubMed Central

    Brodde, O E; Hundhausen, H J; Zerkowski, H R; Michel, M C

    1992-01-01

    1. We studied the effects of chronic calcium antagonist (calcium entry blocker, CEB; nifedipine, verapamil, diltiazem) treatment on beta-adrenoceptor density (assessed by (-)-[125I]-iodocyanopindolol [ICYP] binding) and subtype distribution in right atria from 65 patients without apparent heart failure undergoing elective coronary artery bypass grafting (CAD-patients) and from 13 patients with moderate heart failure (NYHA class III to class III-IV) undergoing mitral valve replacement (MVD-patients). 2. In CAD-patients atrial beta-adrenoceptor density was 79.3 +/- 7.9 fmol ICYP bound mg-1 protein (n = 18), the beta 1:beta 2-adrenoceptor ratio 69:31%. Chronic CEB-treatment did not affect either atrial beta-adrenoceptor density or beta 1:beta 2-adrenoceptor ratio. 3. In contrast, in CAD-patients chronically treated with beta 1-adrenoceptor antagonists (atenolol, bisoprolol, metoprolol) and CEB, atrial beta-adrenoceptor density was significantly increased (108.6 +/- 10.5 fmol ICYP bound mg-1 protein, n = 21); this increase was due to a selective increase in beta 1-adrenoceptors. 4. In MVD-patients atrial beta-adrenoceptor density (55.5 +/- 8.7 fmol ICYP bound mg-1 protein, n = 7) was significantly lower (P less than 0.05) than in CAD-patients; beta 1:beta 2-adrenoceptor ratio, however, was not changed (67:33%). Chronic CEB-treatment of MVD-patients did not prevent the decrease in atrial beta-adrenoceptors. 5. We conclude that chronic CEB-treatment does not affect human right atrial beta-adrenoceptor density, either in patients without apparent heart failure or in patients with moderate heart failure.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1315561

  18. A New Algorithm to Diagnose Atrial Ectopic Origin from Multi Lead ECG Systems - Insights from 3D Virtual Human Atria and Torso

    PubMed Central

    Alday, Erick A. Perez; Colman, Michael A.; Langley, Philip; Butters, Timothy D.; Higham, Jonathan; Workman, Antony J.; Hancox, Jules C.; Zhang, Henggui

    2015-01-01

    Rapid atrial arrhythmias such as atrial fibrillation (AF) predispose to ventricular arrhythmias, sudden cardiac death and stroke. Identifying the origin of atrial ectopic activity from the electrocardiogram (ECG) can help to diagnose the early onset of AF in a cost-effective manner. The complex and rapid atrial electrical activity during AF makes it difficult to obtain detailed information on atrial activation using the standard 12-lead ECG alone. Compared to conventional 12-lead ECG, more detailed ECG lead configurations may provide further information about spatio-temporal dynamics of the body surface potential (BSP) during atrial excitation. We apply a recently developed 3D human atrial model to simulate electrical activity during normal sinus rhythm and ectopic pacing. The atrial model is placed into a newly developed torso model which considers the presence of the lungs, liver and spinal cord. A boundary element method is used to compute the BSP resulting from atrial excitation. Elements of the torso mesh corresponding to the locations of the placement of the electrodes in the standard 12-lead and a more detailed 64-lead ECG configuration were selected. The ectopic focal activity was simulated at various origins across all the different regions of the atria. Simulated BSP maps during normal atrial excitation (i.e. sinoatrial node excitation) were compared to those observed experimentally (obtained from the 64-lead ECG system), showing a strong agreement between the evolution in time of the simulated and experimental data in the P-wave morphology of the ECG and dipole evolution. An algorithm to obtain the location of the stimulus from a 64-lead ECG system was developed. The algorithm presented had a success rate of 93%, meaning that it correctly identified the origin of atrial focus in 75/80 simulations, and involved a general approach relevant to any multi-lead ECG system. This represents a significant improvement over previously developed algorithms. PMID

  19. Effects of Persistent Atrial Fibrillation-Induced Electrical Remodeling on Atrial Electro-Mechanics – Insights from a 3D Model of the Human Atria

    PubMed Central

    Adeniran, Ismail; MacIver, David H.; Garratt, Clifford J.; Ye, Jianqiao; Hancox, Jules C.; Zhang, Henggui

    2015-01-01

    Aims Atrial stunning, a loss of atrial mechanical contraction, can occur following a successful cardioversion. It is hypothesized that persistent atrial fibrillation-induced electrical remodeling (AFER) on atrial electrophysiology may be responsible for such impaired atrial mechanics. This simulation study aimed to investigate the effects of AFER on atrial electro-mechanics. Methods and Results A 3D electromechanical model of the human atria was developed to investigate the effects of AFER on atrial electro-mechanics. Simulations were carried out in 3 conditions for 4 states: (i) the control condition, representing the normal tissue (state 1) and the tissue 2–3 months after cardioversion (state 2) when the atrial tissue recovers its electrophysiological properties after completion of reverse electrophysiological remodelling; (ii) AFER-SR condition for AF-remodeled tissue with normal sinus rhythm (SR) (state 3); and (iii) AFER-AF condition for AF-remodeled tissue with re-entrant excitation waves (state 4). Our results indicate that at the cellular level, AFER (states 3 & 4) abbreviated action potentials and reduced the Ca2+ content in the sarcoplasmic reticulum, resulting in a reduced amplitude of the intracellular Ca2+ transient leading to decreased cell active force and cell shortening as compared to the control condition (states 1 & 2). Consequently at the whole organ level, atrial contraction in AFER-SR condition (state 3) was dramatically reduced. In the AFER-AF condition (state 4) atrial contraction was almost abolished. Conclusions This study provides novel insights into understanding atrial electro-mechanics illustrating that AFER impairs atrial contraction due to reduced intracellular Ca2+ transients. PMID:26606047

  20. Immunosuppression abrogates resistance of young rabbits to Rabbit Haemorrhagic Disease (RHD)

    PubMed Central

    2014-01-01

    Rabbit Haemorrhagic Disease (RHD) is caused by a calicivirus (RHDV) that kills 90% of infected adult European rabbits within 3 days. Remarkably, young rabbits are resistant to RHD. We induced immunosuppression in young rabbits by treatment with methylprednisolone acetate (MPA) and challenged the animals with RHDV by intramuscular injection. All of these young rabbits died within 3 days of infection due to fulminant hepatitis, presenting a large number of RHDV-positive dead or apoptotic hepatocytes, and a significant seric increase in cytokines, features that are similar to those of naïve adult rabbits infected by RHDV. We conclude that MPA-induced immunosuppression abrogates the resistance of young rabbits to RHD, indicating that there are differences in the innate immune system between young and adult rabbits that contribute to their distinct resistance/susceptibility to RHDV infection. PMID:24490832

  1. A sensorimotor theory of temporal tracking and beat induction.

    PubMed

    Todd, N P McAngus; Lee, C S; O'Boyle, D J

    2002-02-01

    In this paper, we develop a theory of the neurobiological basis of temporal tracking and beat induction as a form of sensory-guided action. We propose three principal components for the neurological architecture of temporal tracking: (1) the central auditory system, which represents the temporal information in the input signal in the form of a modulation power spectrum; (2) the musculoskeletal system, which carries out the action and (3) a controller, in the form of a parieto-cerebellar-frontal loop, which carries out the synchronisation between input and output by means of an internal model of the musculoskeletal dynamics. The theory is implemented in the form of a computational algorithm which takes sound samples as input and synchronises a simple linear mass-spring-damper system to simulate audio-motor synchronisation. The model may be applied to both the tracking of isochronous click sequences and beat induction in rhythmic music or speech, and also accounts for the approximate Weberian property of timing. PMID:11963275

  2. Quantum beats in attosecond time-resolved autoionization of krypton

    NASA Astrophysics Data System (ADS)

    Cheng, Yan; Chini, Michael; Tong, Xiao-Min; Chew, Andrew; Biedermann, Julius; Wu, Yi; Cunningham, Eric; Chang, Zenghu

    2015-05-01

    The recent development of attosecond transient absorption spectroscopy (ATAS) has allowed probing of electron dynamics in atoms with few-femtosecond to sub-cycle time scales. Recently, the contribution of quantum beating to the two-color multi-photon excitation process has been proposed and demonstrated in the attosecond transient absorption experiment in the bound state of atoms. Here we performed an attosecond transient absorption experiment with krypton atoms, the attosecond pulse launched electronic wave packets composed of multiple bound excited states and spin-orbit coupling induced autoionization states of krypton atoms. Quantum beats were observed in the autoionizing states near the ionization threshold. Recurrences were observed in the 4s24p5(2 P° 1/2) 6d, 4s24p5(2 P°1/2) 7d, 4s24p5(2 P° 1/2) 8d states with periods of 5-10 fs. The relative phase among these autoionizing states can be retrieved from such measurement, thus allowed the reconstruction of the valence state wave packets. This material is based upon work supported by Army Research Office, Air Force Office of Scientific Research, the National Science Foundation, and the DARPA PULSE program by a grant from AMRDEC.

  3. Unraveling the nature of coherent beatings in chlorosomes

    NASA Astrophysics Data System (ADS)

    Dostál, Jakub; Mančal, Tomáš; Vácha, František; Pšenčík, Jakub; Zigmantas, Donatas

    2014-03-01

    Coherent two-dimensional (2D) spectroscopy at 80 K was used to study chlorosomes isolated from green sulfur bacterium Chlorobaculum tepidum. Two distinct processes in the evolution of the 2D spectrum are observed. The first being exciton diffusion, seen in the change of the spectral shape occurring on a 100-fs timescale, and the second being vibrational coherences, realized through coherent beatings with frequencies of 91 and 145 cm-1 that are dephased during the first 1.2 ps. The distribution of the oscillation amplitude in the 2D spectra is independent of the evolution of the 2D spectral shape. This implies that the diffusion energy transfer process does not transfer coherences within the chlorosome. Remarkably, the oscillatory pattern observed in the negative regions of the 2D spectrum (dominated by the excited state absorption) is a mirror image of the oscillations found in the positive part (originating from the stimulated emission and ground state bleach). This observation is surprising since it is expected that coherences in the electronic ground and excited states are generated with the same probability and the latter dephase faster in the presence of fast diffusion. Moreover, the relative amplitude of coherent beatings is rather high compared to non-oscillatory signal despite the reported low values of the Huang-Rhys factors. The origin of these effects is discussed in terms of the vibronic and Herzberg-Teller couplings.

  4. QRS template matching for recognition of ventricular ectopic beats.

    PubMed

    Krasteva, Vessela; Jekova, Irena

    2007-12-01

    We propose a quasi real-time method for discrimination of ventricular ectopic beats from both supraventricular and paced beats in the electrocardiogram (ECG). The heartbeat waveforms were evaluated within a fixed-length window around the fiducial points (100 ms before, 450 ms after). Our algorithm was designed to operate with minimal expert intervention and we define that the operator is required only to initially select up to three 'normal' heartbeats (the most frequently seen supraventricular or paced complexes). These were named original QRS templates and their copies were substituted continuously throughout the ECG analysis to capture slight variations in the heartbeat waveforms of the patient's sustained rhythm. The method is based on matching of the evaluated heartbeat with the QRS templates by a complex set of ECG descriptors, including maximal cross-correlation, area difference and frequency spectrum difference. Temporal features were added by analyzing the R-R intervals. The classification criteria were trained by statistical assessment of the ECG descriptors calculated for all heartbeats in MIT-BIH Supraventricular Arrhythmia Database. The performance of the classifiers was tested on the independent MIT-BIH Arrhythmia Database. The achieved unbiased accuracy is represented by sensitivity of 98.4% and specificity of 98.86%, both being competitive to other published studies. The provided computationally efficient techniques enable the fast post-recording analysis of lengthy Holter-monitor ECG recordings, as well as they can serve as a quasi real-time detection method embedded into surface ECG monitors. PMID:17805974

  5. Analysis of the forces acting on beating cilia

    NASA Astrophysics Data System (ADS)

    Sangani, Ashok S.; Vidyadharan, Jyothish; Foster, Kenneth W.

    2016-06-01

    Detailed analysis of the forces acting on a uniform-diameter beating cilium is carried out to determine the moment generated by the inter-doublet forces acting along the length of a cilium and the results are compared with the sliding-control theory according to which the moment is a function of the interdoublet sliding. In the central part of the cilium the inter-doublet forces are found to be proportional to the inter-doublet sliding. However, in spite of the uniformity of the diameter of the cilium, the proportionality constant, known as the dynamic stiffness, is not constant along its entire length. Significant variations are observed in the regions both near the tip of the cilium and proximal to the cell body. In the tip region the magnitude of the dynamic stiffness is found to decrease. This decrease is probably due to decrease in the number density of the molecular motors in that region and in the number of doublet microtubules. The behavior in the proximal region, on the other hand, does not appear to be well described by the sliding control theory. Our analysis therefore suggests that the dynamics of ciliary beating cannot be adequately described by a simple sliding-control theory with constant dynamic stiffness. Our analysis suggests that the cilium is differentiated into a basal region optimized for the creation of a wave and a central region optimized to support a traveling wave that provides the thrust for the cell.

  6. Beyond the beat: modeling metric structure in music and performance.

    PubMed

    Tomic, Stefan T; Janata, Petr

    2008-12-01

    Current models for capturing metric structure of recordings of music are concerned primarily with the task of tempo and beat estimation. Even though these models have the potential for extracting other metric and rhythmic information, this potential has not been realized. In this paper, a model for describing the general metric structure of audio signals and behavioral data is presented. This model employs reson filters, rather than the comb filters used in earlier models. The oscillatory nature of reson filters is investigated, as they may be better suited for extracting multiple metric levels in the onset patterns of acoustic signals. The model is tested with several types of sequences of Dirac impulses as inputs, in order to investigate the model's sensitivity to timing variations and accent structure. The model's responses to natural stimuli are illustrated, both for excerpts of recorded music from a large database utilized by tempo-estimation models, and sequences of taps from a bimanual tapping task. Finally, the relationship of the model to several other beat-finding and rhythm models is discussed, and several applications and extensions for the model are suggested. PMID:19206825

  7. Blow-Out Fracture due to a Hazel Stick Beat.

    PubMed

    Erbilen, Esin; Yuksel, Harun; Onder, H Ibrahim; Tunc, Murat; Kaya, Murat

    2008-12-01

    The aim of this case report is to demonstrate that blow-out fractures can occur not only by a classical trauma mechanism but also from the consequences of a stick beat. A 66-year-old male was admitted to our hospital complaining of a sudden swelling of his right eyelid after blowing his nose. In his medical history there was the report of a hazel stick beat the previous day. Upon ophthalmological examination, ecchymosis was observed in the right orbital region, and subcutaneous amphisema in addition to a dense subconjunctival hemorrhage were detected. Using computed tomography (CT), the intraorbital air density in the soft tissues and the right maxillary sinus wall fracture possessing fluid density compatible with hemorrhage was observed. The patient was treated conservatively with prednisolone and antibiotics. We conclude that a blow-out fracture may occur in patients who experience orbital trauma, even in cases of low-energy trauma. These patients may be symptomatic after an episode of hard nose-blowing. PMID:25610052

  8. Robust estimation of the motile cilia beating frequency.

    PubMed

    Meste, O; Brau, F; Guyon, A

    2015-10-01

    The estimation of the cilia beating frequency (CBF) is of great interest in understanding how the CBF modulates liquid fluxes and how it is controlled by the ciliated cell intra- and/or extracellular medium composition in physiological processes. Motion artifacts and camera defaults may hinder the computation of the frequency variations during long-lasting experiments. We have developed a new analysis approach consisting of a preliminary corrective step (removal of a grid pattern on the image sequence and shift compensation), followed by a harmonic model of the observed cilia using a maximum likelihood estimator framework. It is shown that a more accurate estimation of the frequency can be obtained by averaging the squared Fourier transform of individual pixels followed by a particular summation over the different frequencies, namely the compressed spectrum. Robustness of the proposed method over traditional approaches is shown by several examples and simulations. The method is then applied to images of samples containing ciliated ependymal cells located in the third cerebral ventricle of mouse brains, showing that even small variations in CBF in response to changes in the amount of oxygenation, pH or glucose were clearly visible in the computed frequencies. As a conclusion, this method reveals a fine metabolic tuning of the cilia beating in ependimocytes lining the third cerebral ventricle. Such regulations are likely to participate in homeostatic mechanisms regulating CSF movements and brain energy supply. PMID:26215519

  9. Unraveling the nature of coherent beatings in chlorosomes

    SciTech Connect

    Dostál, Jakub; Mančal, Tomáš; Pšenčík, Jakub; Vácha, František; Zigmantas, Donatas

    2014-03-21

    Coherent two-dimensional (2D) spectroscopy at 80 K was used to study chlorosomes isolated from green sulfur bacterium Chlorobaculum tepidum. Two distinct processes in the evolution of the 2D spectrum are observed. The first being exciton diffusion, seen in the change of the spectral shape occurring on a 100-fs timescale, and the second being vibrational coherences, realized through coherent beatings with frequencies of 91 and 145 cm{sup −1} that are dephased during the first 1.2 ps. The distribution of the oscillation amplitude in the 2D spectra is independent of the evolution of the 2D spectral shape. This implies that the diffusion energy transfer process does not transfer coherences within the chlorosome. Remarkably, the oscillatory pattern observed in the negative regions of the 2D spectrum (dominated by the excited state absorption) is a mirror image of the oscillations found in the positive part (originating from the stimulated emission and ground state bleach). This observation is surprising since it is expected that coherences in the electronic ground and excited states are generated with the same probability and the latter dephase faster in the presence of fast diffusion. Moreover, the relative amplitude of coherent beatings is rather high compared to non-oscillatory signal despite the reported low values of the Huang-Rhys factors. The origin of these effects is discussed in terms of the vibronic and Herzberg-Teller couplings.

  10. Efficient heart beat detection using embedded system electronics

    NASA Astrophysics Data System (ADS)

    Ramasamy, Mouli; Oh, Sechang; Varadan, Vijay K.

    2014-04-01

    The present day bio-technical field concentrates on developing various types of innovative ambulatory and wearable devices to monitor several bio-physical, physio-pathological, bio-electrical and bio-potential factors to assess a human body's health condition without intruding quotidian activities. One of the most important aspects of this evolving technology is monitoring heart beat rate and electrocardiogram (ECG) from which many other subsidiary results can be derived. Conventionally, the devices and systems consumes a lot of power since the acquired signals are always processed on the receiver end. Because of this back end processing, the unprocessed raw data is transmitted resulting in usage of more power, memory and processing time. This paper proposes an innovative technique where the acquired signals are processed by a microcontroller in the front end of the module and just the processed signal is then transmitted wirelessly to the display unit. Therefore, power consumption is considerably reduced and clearer data analysis is performed within the module. This also avoids the need for the user to be educated about usage of the device and signal/system analysis, since only the number of heart beats will displayed at the user end. Additionally, the proposed concept also eradicates the other disadvantages like obtrusiveness, high power consumption and size. To demonstrate the above said factors, a commercial controller board was used to extend the monitoring method by using the saved ECG data from a computer.

  11. Ionophore antibiotic (narasin) poisoning in rabbits.

    PubMed

    Salles, M S; Lombardo de Barros, C S; Barros, S S

    1994-10-01

    Outbreaks of narasin poisoning in rabbits from several commercial rabbit-raising farms in the state of Parana, Brazil, are reported. Approximately 5,000/35,000 rabbits died after having consumed a pelleted ration to which poultry ration premix had been added. Clinical signs included apathy, anorexia, muscle weakness, impaired walking, diarrhea, respiratory distress, and opistothonus. Gross findings were not remarkable, but varying degrees of degeneration, necrosis and regeneration of skeletal muscles were consistent histopathological features in affected rabbits. Myocardial changes were mild or absent. Thirty ppm of narasin were detected in the ration fed the rabbits. The disease was experimentally reproduced by feeding the suspected ration and by administering narasin po to rabbits. PMID:7839570

  12. The role of the basal ganglia in beat perception: neuroimaging and neuropsychological investigations.

    PubMed

    Grahn, Jessica A

    2009-07-01

    Perception of musical rhythms is culturally universal. Despite this special status, relatively little is known about the neurobiology of rhythm perception, particularly with respect to beat processing. Findings are presented here from a series of studies that have specifically examined the neural basis of beat perception, using functional magnetic resonance imaging (fMRI) and studying patients with Parkinson's disease. fMRI data indicate that novel beat-based sequences robustly activate the basal ganglia when compared to irregular, nonbeat sequences. Furthermore, although most healthy participants find it much easier to discriminate changes in beat-based sequences compared to irregular sequences, Parkinson's disease patients fail to show the same degree of benefit. Taken together, these data suggest that the basal ganglia are performing a crucial function in beat processing. The results of an additional fMRI study indicate that the role of the basal ganglia is strongly linked to internal generation of the beat. Basal ganglia activity is greater when participants listen to rhythms in which internal generation of the beat is required, as opposed to rhythms with strongly externally cued beats. Functional connectivity between part of the basal ganglia (the putamen) and cortical motor areas (premotor and supplementary motor areas) is also higher during perception of beat rhythms compared to nonbeat rhythms. Increased connectivity between cortical motor and auditory areas is found in those with musical training. The findings from these converging methods strongly implicate the basal ganglia in processing a regular beat, particularly when internal generation of the beat is required. PMID:19673753

  13. Interacting cortical and basal ganglia networks underlying finding and tapping to the musical beat.

    PubMed

    Kung, Shu-Jen; Chen, Joyce L; Zatorre, Robert J; Penhune, Virginia B

    2013-03-01

    Humans are able to find and tap to the beat of musical rhythms varying in complexity from children's songs to modern jazz. Musical beat has no one-to-one relationship with auditory features-it is an abstract perceptual representation that emerges from the interaction between sensory cues and higher-level cognitive organization. Previous investigations have examined the neural basis of beat processing but have not tested the core phenomenon of finding and tapping to the musical beat. To test this, we used fMRI and had musicians find and tap to the beat of rhythms that varied from metrically simple to metrically complex-thus from a strong to a weak beat. Unlike most previous studies, we measured beat tapping performance during scanning and controlled for possible effects of scanner noise on beat perception. Results showed that beat finding and tapping recruited largely overlapping brain regions, including the superior temporal gyrus (STG), premotor cortex, and ventrolateral PFC (VLPFC). Beat tapping activity in STG and VLPFC was correlated with both perception and performance, suggesting that they are important for retrieving, selecting, and maintaining the musical beat. In contrast BG activity was similar in all conditions and was not correlated with either perception or production, suggesting that it may be involved in detecting auditory temporal regularity or in associating auditory stimuli with a motor response. Importantly, functional connectivity analyses showed that these systems interact, indicating that more basic sensorimotor mechanisms instantiated in the BG work in tandem with higher-order cognitive mechanisms in PFC. PMID:23163420

  14. Enteropathogenic Escherichia coli Prevalence in Laboratory Rabbits

    PubMed Central

    Swennes, Alton G.; Buckley, Ellen M.; Madden, Carolyn M.; Byrd, Charles P.; Donocoff, Rachel S.; Rodriguez, Loretta; Parry, Nicola M. A.; Fox, James G.

    2013-01-01

    Rabbit-origin enteropathogenic E. coli (EPEC) causes substantial diarrhea-associated morbidity and has zoonotic potential. A culture-based survey was undertaken to ascertain its prevalence. EPEC was isolated from 6/141 (4.3%) commercially-acquired laboratory rabbits. Three of these did not have diarrhea or EPEC-typical intestinal lesions; they instead had background plasmacytic intestinal inflammation. Asymptomatically infected rabbits may function as EPEC reservoirs. PMID:23391439

  15. Changes in intracellular calcium concentration influence beat-to-beat variability of action potential duration in canine ventricular myocytes.

    PubMed

    Kistamas, K; Szentandrassy, N; Hegyi, B; Vaczi, K; Ruzsnavszky, F; Horvath, B; Banyasz, T; Nanasi, P P; Magyar, J

    2015-02-01

    The aim of the present work was to study the influence of changes in intracellular calcium concentration ([Ca(2+)]i) on beat-to-beat variability (short term variability, SV) of action potential duration (APD) in isolated canine ventricular cardiomyocytes. Series of action potentials were recorded from enzymatically isolated canine ventricular cells using conventional microelectrode technique. Drug effects on SV were evaluated as relative SV changes determined by plotting the drug-induced changes in SV against corresponding changes in APD and comparing these data to the exponential SV-APD function obtained with inward and outward current injections. Exposure of myocytes to the Ca(2+) chelator BAPTA-AM (5 μM) decreased, while Ca(2+) ionophore A23187 (1 μM) increased the magnitude of relative SV. Both effects were primarily due to the concomitant changes in APD. Relative SV was reduced by BAPTA-AM under various experimental conditions including pretreatment with veratridine, BAY K8644, dofetilide or E-4031. Contribution of transient changes of [Ca(2+)]i due to Ca(2+) released from the sarcoplasmic reticulum (SR) was studied using 10 μM ryanodine and 1 μM cyclopiazonic acid: relative SV was reduced by both agents. Inhibition of the Na(+)-Ca(2+) exchanger by 1 μM SEA0400 increased relative SV. It is concluded that elevation of [Ca(2+)]i increases relative SV significantly. More importantly, Ca(2+) released from the SR is an important component of this effect. PMID:25716967

  16. Towards Active Tracking of Beating Heart Motion in the Presence of Arrhythmia for Robotic Assisted Beating Heart Surgery

    PubMed Central

    Tuna, E. Erdem; Karimov, Jamshid H.; Liu, Taoming; Bebek, Özkan; Fukamachi, Kiyotaka; Çavuşoğlu, M. Cenk

    2014-01-01

    In robotic assisted beating heart surgery, the control architecture for heart motion tracking has stringent requirements in terms of bandwidth of the motion that needs to be tracked. In order to achieve sufficient tracking accuracy, feed-forward control algorithms, which rely on estimations of upcoming heart motion, have been proposed in the literature. However, performance of these feed-forward motion control algorithms under heart rhythm variations is an important concern. In their past work, the authors have demonstrated the effectiveness of a receding horizon model predictive control-based algorithm, which used generalized adaptive predictors, under constant and slowly varying heart rate conditions. This paper extends these studies to the case when the heart motion statistics change abruptly and significantly, such as during arrhythmias. A feasibility study is carried out to assess the motion tracking capabilities of the adaptive algorithms in the occurrence of arrhythmia during beating heart surgery. Specifically, the tracking performance of the algorithms is evaluated on prerecorded motion data, which is collected in vivo and includes heart rhythm irregularities. The algorithms are tested using both simulations and bench experiments on a three degree-of-freedom robotic test bed. They are also compared with a position-plus-derivative controller as well as a receding horizon model predictive controller that employs an extended Kalman filter algorithm for predicting future heart motion. PMID:25048462

  17. External Counterpulsation Reduces Beat-to-Beat Blood Pressure Variability When Augmenting Blood Pressure and Cerebral Blood Flow in Ischemic Stroke

    PubMed Central

    Tian, Ge; Xiong, Li; Lin, Wenhua; Han, Jinghao; Chen, Xiangyan; Leung, Thomas Wai Hong; Soo, Yannie Oi Yan

    2016-01-01

    Background and Purpose External counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. Methods We enrolled recent ischemic stroke patients and healthy controls. Changes in the blood flow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and after ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04–0.15 Hz), and high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. Results We found that ECP significantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. The decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not differ from those in healthy controls. The change in flow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). Conclusions ECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood flow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies. PMID:27095525

  18. The impact of varying autonomic states on the dynamic beat-to-beat QT–RR and QT–TQ interval relationships

    PubMed Central

    Fossa, A A

    2008-01-01

    The beat-to-beat dynamicity of the QT–RR interval relationship is difficult to assess with the use of traditional correction factors (QTc) and changes in QTc do not accurately reflect or quantify arrhythmogenic risk. Further, the interpretation of arrhythmogenic risk is influenced by autonomic state. To visualize the QT–RR interval dynamics under varying conditions of autonomic state from impaired repolarization, we have developed a system to sequentially plot the beat-to-beat confluence of ECG data or ‘clouds' obtained from conscious dogs and humans. To represent the non-uniformity of the clouds, a bootstrap sampling method that computes the mathematical centre of the uncorrected beat-to-beat QT value (QTbtb) and defines the upper and lower 95% confidence bounds is used. The same method can also be used to examine heterogeneity, hysteresis (both acceleration and deceleration) and restitution (beat-to-beat QT–TQ interval relationship). Impaired repolarization with the combination of E-4031 and L-768,673 (inhibitor of IKs current) increased heterogeneity of restitution at rest 55–91%; increased hysteresis during heart rate acceleration after isoproterenol challenge by approximately 40–60%; and dramatically diminished the minimum TQ boundary by 72% to only 28 ms. Impaired repolarization alters restitution during normal sinus rhythm and increases hysteresis/heterogeneity during heart rate acceleration following sympathetic stimulation. These findings are supported by similar clinical observations in LQT1 and LQT2 syndromes. Therefore, the assessment of the dynamic QT–RR and QT–TQ interval relationships through quantification of heterogeneity, hysteresis and restitution may allow a more accurate non-invasive evaluation of the conditions leading to cardiac arrhythmia. PMID:18663381

  19. Comparison of real beat-to-beat signals with commercially available 4 Hz sampling on the evaluation of foetal heart rate variability.

    PubMed

    Gonçalves, Hernâni; Costa, Antónia; Ayres-de-Campos, Diogo; Costa-Santos, Cristina; Rocha, Ana Paula; Bernardes, João

    2013-06-01

    Evaluation of foetal heart rate (FHR) variability is an essential part of foetal monitoring, but a precise quantification of this parameter depends on the quality of the signal. In this study, we compared real FHR beat-to-beat signals with 4 Hz sampling provided by commercial foetal monitors on linear and nonlinear indices and analysed their clinical implications. Simultaneous acquisition of beat-to-beat signals and their 4 Hz sampling rate counterparts was performed using a scalp electrode, during the last hour of labour in 21 fetuses born with an umbilical artery blood (UAB) pH ≥ 7.20 and 6 born with an UAB pH < 7.20. For each case, the first and last 10 min segments were analysed, using time and frequency domain linear, and nonlinear FHR indices, namely mean FHR, low frequency, high frequency, approximate, sample and multiscale entropy. Significant differences in variability indices were found between beat-to-beat and 4 Hz sampled signals, with a lesser effect seen with 2 Hz sampling. These differences did not affect physiological changes observed during labour progression, such as decreased entropy and linear time domain indices, and increased frequency domain indices. However, significant differences were found in the discrimination between fetuses born with different UAB pHs, with beat-to-beat sampling providing better results in linear indices and 4 Hz sampling better results in entropy indices. In conclusion, different FHR sampling frequencies can significantly affect the quantification of variability indices. This needs to be taken into account in the interpretation of FHR variability and in the development of new equipment. PMID:23345009

  20. Keeping the Beat: A Large Sample Study of Bouncing and Clapping to Music

    PubMed Central

    Tranchant, Pauline; Vuvan, Dominique T.; Peretz, Isabelle

    2016-01-01

    The vast majority of humans move in time with a musical beat. This behaviour has been mostly studied through finger-tapping synchronization. Here, we evaluate naturalistic synchronization responses to music–bouncing and clapping–in 100 university students. Their ability to match the period of their bounces and claps to those of a metronome and musical clips varying in beat saliency was assessed. In general, clapping was better synchronized with the beat than bouncing, suggesting that the choice of a specific movement type is an important factor to consider in the study of sensorimotor synchronization processes. Performance improved as a function of beat saliency, indicating that beat abstraction plays a significant role in synchronization. Fourteen percent of the population exhibited marked difficulties with matching the beat. Yet, at a group level, poor synchronizers showed similar sensitivity to movement type and beat saliency as normal synchronizers. These results suggest the presence of quantitative rather than qualitative variations when losing the beat. PMID:27471854

  1. Beat-wave Photoinjector for Generating Periodic Electron Bunches at THz Frequencies

    SciTech Connect

    Huang, Y.-C.; Chen, C.-H.; Lau, W.-K.

    2009-01-22

    A laser beat wave is proposed to induce density modulated electron emission from a photocathode and is thereby used to generate a periodically bunched electron beam from a photocathode electron accelerator. This technique does not introduce additional energy spread or emittance to the electron beam. We also present a laser system for this purpose with a tunable beat frequency up to 40 THz.

  2. 77 FR 19015 - Announcement of Requirements and Registration for Beat Down Blood Pressure Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-29

    ... Health and Human Services (HHS) published a notice in the Federal Register (77 FR 17060) announcing requirements and registration for a Beat Down Blood Pressure Video Challenge. This challenge will not be open... HUMAN SERVICES Announcement of Requirements and Registration for Beat Down Blood Pressure...

  3. 77 FR 17060 - Announcement of Requirements and Registration for Beat Down Blood Pressure Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... HUMAN SERVICES Announcement of Requirements and Registration for Beat Down Blood Pressure Challenge... years, announces the launch of the Beat Down Blood Pressure Video Challenge. This challenge is an open... consumer e-health tools to manage high blood pressure. Health care providers are also encouraged to...

  4. The Short Supply of Saints: Limits on Replication of Models that "Beat the Odds"

    ERIC Educational Resources Information Center

    Wilder, Tamara; Jacobsen, Rebecca

    2010-01-01

    Researchers have identified effective practices that allow schools to "beat the odds" and close the reading achievement gap. Although identifying these practices is important, researchers have paid little attention to the work it takes to implement them. Through interviews with teachers who work at schools identified as beating the odds, this…

  5. Beat processing is pre-attentive for metrically simple rhythms with clear accents: an ERP study.

    PubMed

    Bouwer, Fleur L; Van Zuijen, Titia L; Honing, Henkjan

    2014-01-01

    The perception of a regular beat is fundamental to music processing. Here we examine whether the detection of a regular beat is pre-attentive for metrically simple, acoustically varying stimuli using the mismatch negativity (MMN), an ERP response elicited by violations of acoustic regularity irrespective of whether subjects are attending to the stimuli. Both musicians and non-musicians were presented with a varying rhythm with a clear accent structure in which occasionally a sound was omitted. We compared the MMN response to the omission of identical sounds in different metrical positions. Most importantly, we found that omissions in strong metrical positions, on the beat, elicited higher amplitude MMN responses than omissions in weak metrical positions, not on the beat. This suggests that the detection of a beat is pre-attentive when highly beat inducing stimuli are used. No effects of musical expertise were found. Our results suggest that for metrically simple rhythms with clear accents beat processing does not require attention or musical expertise. In addition, we discuss how the use of acoustically varying stimuli may influence ERP results when studying beat processing. PMID:24870123

  6. Keeping the Beat: A Large Sample Study of Bouncing and Clapping to Music.

    PubMed

    Tranchant, Pauline; Vuvan, Dominique T; Peretz, Isabelle

    2016-01-01

    The vast majority of humans move in time with a musical beat. This behaviour has been mostly studied through finger-tapping synchronization. Here, we evaluate naturalistic synchronization responses to music-bouncing and clapping-in 100 university students. Their ability to match the period of their bounces and claps to those of a metronome and musical clips varying in beat saliency was assessed. In general, clapping was better synchronized with the beat than bouncing, suggesting that the choice of a specific movement type is an important factor to consider in the study of sensorimotor synchronization processes. Performance improved as a function of beat saliency, indicating that beat abstraction plays a significant role in synchronization. Fourteen percent of the population exhibited marked difficulties with matching the beat. Yet, at a group level, poor synchronizers showed similar sensitivity to movement type and beat saliency as normal synchronizers. These results suggest the presence of quantitative rather than qualitative variations when losing the beat. PMID:27471854

  7. Beat Processing Is Pre-Attentive for Metrically Simple Rhythms with Clear Accents: An ERP Study

    PubMed Central

    Bouwer, Fleur L.; Van Zuijen, Titia L.; Honing, Henkjan

    2014-01-01

    The perception of a regular beat is fundamental to music processing. Here we examine whether the detection of a regular beat is pre-attentive for metrically simple, acoustically varying stimuli using the mismatch negativity (MMN), an ERP response elicited by violations of acoustic regularity irrespective of whether subjects are attending to the stimuli. Both musicians and non-musicians were presented with a varying rhythm with a clear accent structure in which occasionally a sound was omitted. We compared the MMN response to the omission of identical sounds in different metrical positions. Most importantly, we found that omissions in strong metrical positions, on the beat, elicited higher amplitude MMN responses than omissions in weak metrical positions, not on the beat. This suggests that the detection of a beat is pre-attentive when highly beat inducing stimuli are used. No effects of musical expertise were found. Our results suggest that for metrically simple rhythms with clear accents beat processing does not require attention or musical expertise. In addition, we discuss how the use of acoustically varying stimuli may influence ERP results when studying beat processing. PMID:24870123

  8. Focusing on the Basics in Beat-the-Odds Schools. Policy Brief

    ERIC Educational Resources Information Center

    Lefkowits, Laura; Woempner, Carolyn

    2006-01-01

    Researchers at Mid-Continent Research for Education and Learning (McREL) recently completed a study of "beat-the-odds" schools--high-needs schools that demonstrated atypically high student achievement. This policy brief draws from the report of the study's findings, "High-Needs Schools--What Does It Take to Beat the Odds?"…

  9. Passive fetal heart rate monitoring apparatus and method with enhanced fetal heart beat discrimination

    NASA Technical Reports Server (NTRS)

    Zahorian, Stephen A. (Inventor); Livingston, David L. (Inventor); Pretlow, III, Robert A. (Inventor)

    1996-01-01

    An apparatus for acquiring signals emitted by a fetus, identifying fetal heart beats and determining a fetal heart rate. Multiple sensor signals are outputted by a passive fetal heart rate monitoring sensor. Multiple parallel nonlinear filters filter these multiple sensor signals to identify fetal heart beats in the signal data. A processor determines a fetal heart rate based on these identified fetal heart beats. The processor includes the use of a figure of merit weighting of heart rate estimates based on the identified heart beats from each filter for each signal. The fetal heart rate thus determined is outputted to a display, storage, or communications channel. A method for enhanced fetal heart beat discrimination includes acquiring signals from a fetus, identifying fetal heart beats from the signals by multiple parallel nonlinear filtering, and determining a fetal heart rate based on the identified fetal heart beats. A figure of merit operation in this method provides for weighting a plurality of fetal heart rate estimates based on the identified fetal heart beats and selecting the highest ranking fetal heart rate estimate.

  10. Measurement of the Frequencies of One Octave in a Harmonium by Counting Beats.

    ERIC Educational Resources Information Center

    Datta, Somnath

    1991-01-01

    An experiment intended to familiarize a student with the musical scale and the technique of tuning an instrument by listening for beats is described. From the dial reading of the oscillator frequency and the counted beats frequency, the student then computes the frequency of each musical note over one full octave. (Author)

  11. Attitudes toward Wife Beating among Palestinian Women of Reproductive Age from Three Cities in West Bank

    ERIC Educational Resources Information Center

    Dhaher, Enas A.; Mikolajczyk, Rafael T.; Maxwell, Annette E.; Kramer, Alexander

    2010-01-01

    A total of 450 women were interviewed in Mother and Child Health Care Centers in three cities in West Bank, Palestine, to assess attitudes toward wife beating. Overall, women perceived wife beating to be justified if a wife insults her husband (59%), if she disobeys her husband (49%), if she neglects her children (37%), if she goes out without…

  12. Algorithm for identifying and separating beats from arterial pulse records

    PubMed Central

    Treo, Ernesto F; Herrera, Myriam C; Valentinuzzi, Max E

    2005-01-01

    Background This project was designed as an epidemiological aid-selecting tool for a small country health center with the general objective of screening out possible coronary patients. Peripheral artery function can be non-invasively evaluated by impedance plethysmography. Changes in these vessels appear as good predictors of future coronary behavior. Impedance plethysmography detects volume variations after simple occlusive maneuvers that may show indicative modifications in arterial/venous responses. Averaging of a series of pulses is needed and this, in turn, requires proper determination of the beginning and end of each beat. Thus, the objective here is to describe an algorithm to identify and separate out beats from a plethysmographic record. A secondary objective was to compare the output given by human operators against the algorithm. Methods The identification algorithm detected the beat's onset and end on the basis of the maximum rising phase, the choice of possible ventricular systolic starting points considering cardiac frequency, and the adjustment of some tolerance values to optimize the behavior. Out of 800 patients in the study, 40 occlusive records (supradiastolic- subsystolic) were randomly selected without any preliminary diagnosis. Radial impedance plethysmographic pulse and standard ECG were recorded digitizing and storing the data. Cardiac frequency was estimated with the Power Density Function and, thereafter, the signal was derived twice, followed by binarization of the first derivative and rectification of the second derivative. The product of the two latter results led to a weighing signal from which the cycles' onsets and ends were established. Weighed and frequency filters are needed along with the pre-establishment of their respective tolerances. Out of the 40 records, 30 seconds strands were randomly chosen to be analyzed by the algorithm and by two operators. Sensitivity and accuracy were calculated by means of the true/false and

  13. Beat-by-beat analysis of cardiac output and blood pressure responses to short-term barostimulation in different body positions

    NASA Astrophysics Data System (ADS)

    Hildebrandt, Wulf; Schütze, Harald; Stegemann, J.

    Rapid quantification of the human baro-reflex control of heart rate has been achieved on a beat-by-beat basis using a neck-chamber with quick ECG-triggered pressure changes. Referring to recent findings on heart rate and stroke volume, the present study uses this technique to compare cardiac output as well as blood pressure changes in supine and upright position to investigate feedback effects and to confirm postural reflex modifications not revealed by RR-interval changes. A suction profile starting at +40 mmHg and running 7 steps of pressure decrease down to -65 mmHg was examined in 0° and 90° tilting position while beat-by-beat recordings were done of heart rate, stroke volume (impedance-cardiography) and blood pressure (Finapres tm) (n=16). The percentual heart rate decrease failed to be significantly different between positions. A suction-induced stroke volume increase led to a cardiac output almost maintained when supine and significantly increased when upright. A decrease in all blood pressure values was found during suction, except for systolic values in upright position which increased. Conclusively, (a) it is confirmed that different inotropy accounts for the seen gravitational effect on the cardiac output not represented by heart rate; (b) identical suction levels in different positions lead to different stimuli at the carotid receptor. This interference has to be considered in microgravity studies by beat-by-beat measurement of cardiac output and blood pressure.

  14. Mitochondrial calcium transients in adult rabbit cardiac myocytes: inhibition by ruthenium red and artifacts caused by lysosomal loading of Ca(2+)-indicating fluorophores.

    PubMed Central

    Trollinger, D R; Cascio, W E; Lemasters, J J

    2000-01-01

    A cold/warm loading protocol was used to ester-load Rhod 2 into mitochondria and other organelles and Fluo 3 into the cytosol of adult rabbit cardiac myocytes for confocal fluorescence imaging. Transient increases in both cytosolic Fluo 3 and mitochondrial Rhod 2 fluorescence occurred after electrical stimulation. Ruthenium red, a blocker of the mitochondrial Ca(2+) uniporter, inhibited mitochondrial Rhod 2 fluorescence transients but not cytosolic Fluo 3 transients. Thus the ruthenium red-sensitive mitochondrial Ca(2+) uniporter catalyzes Ca(2+) uptake during beat-to-beat transients of mitochondrial free Ca(2+), which in turn may help match mitochondrial ATP production to myocardial ATP demand. After ester loading, substantial amounts of Ca(2+)-indicating fluorophores localized into an acidic lysosomal/endosomal compartment. This lysosomal fluorescence did not respond to electrical stimulation. Because fluorescence arose predominantly from lysosomes after the cold loading/warm incubation procedure, total cellular fluorescence failed to track beat-to-beat changes of mitochondrial fluorescence. Only three-dimensionally resolved confocal imaging distinguished the relatively weak mitochondrial signal from the bright lysosomal fluorescence. PMID:10866936

  15. Attitudes toward wife beating among Palestinian women of reproductive age from three cities in West Bank.

    PubMed

    Dhaher, Enas A; Mikolajczyk, Rafael T; Maxwell, Annette E; Krämer, Alexander

    2010-03-01

    A total of 450 women were interviewed in Mother and Child Health Care Centers in three cities in West Bank, Palestine, to assess attitudes toward wife beating. Overall, women perceived wife beating to be justified if a wife insults her husband (59%), if she disobeys her husband (49%), if she neglects her children (37%), if she goes out without telling her husband (25%), if she argues with her husband (11%), and if she burns the food (5%). Sixty-five percent of women agreed with at least one reason for wife beating, but there were statistically significant regional differences: Wife beating was most accepted in Jenin (73% acceptance of at least one reason) and least accepted in Hebron (55%). Lower level of education, not being employed, having more than one child, being married for fewer than 10 years, and making few household decisions were all associated with women's acceptance of wife beating. The implications of these results are discussed. PMID:19494245

  16. Simple non-invasive analysis of embryonic stem cell-derived cardiomyocytes beating in vitro

    NASA Astrophysics Data System (ADS)

    Radaszkiewicz, Katarzyna Anna; Sýkorová, Dominika; Karas, Pavel; Kudová, Jana; Kohút, Lukáš; Binó, Lucia; Večeřa, Josef; Víteček, Jan; Kubala, Lukáš; Pacherník, Jiří

    2016-02-01

    The analysis of digital video output enables the non-invasive screening of various active biological processes. For the monitoring and computing of the beating parameters of cardiomyocytes in vitro, CB Analyser (cardiomyocyte beating analyser) software was developed. This software is based on image analysis of the video recording of beating cardiomyocytes. CB Analyser was tested using cardiomyocytes derived from mouse embryonic stem cells at different stages of cardiomyogenesis. We observed that during differentiation (from day 18), the beat peak width decreased, which corresponded to the increased speed of an individual pulse. However, the beating frequency did not change. Further, the effects of epinephrine modulating mature cardiomyocyte functions were tested to validate the CB Analyser analysis. In conclusion, data show that CB Analyser is a useful tool for evaluating the functions of both developing and mature cardiomyocytes under various conditions in vitro.

  17. Auditory Beat Stimulation and its Effects on Cognition and Mood States

    PubMed Central

    Chaieb, Leila; Wilpert, Elke Caroline; Reber, Thomas P.; Fell, Juergen

    2015-01-01

    Auditory beat stimulation may be a promising new tool for the manipulation of cognitive processes and the modulation of mood states. Here, we aim to review the literature examining the most current applications of auditory beat stimulation and its targets. We give a brief overview of research on auditory steady-state responses and its relationship to auditory beat stimulation (ABS). We have summarized relevant studies investigating the neurophysiological changes related to ABS and how they impact upon the design of appropriate stimulation protocols. Focusing on binaural-beat stimulation, we then discuss the role of monaural- and binaural-beat frequencies in cognition and mood states, in addition to their efficacy in targeting disease symptoms. We aim to highlight important points concerning stimulation parameters and try to address why there are often contradictory findings with regard to the outcomes of ABS. PMID:26029120

  18. Ca2+-dependent regulation of beat frequency of cilia in Paramecium.

    PubMed

    Nakaoka, Y; Tanaka, H; Oosawa, F

    1984-01-01

    Triton-extracted models of Paramecium cells prepared in the presence of Mg2+ and EGTA showed Ca2+ sensitivity not only in the direction of beat but also in the beat frequency of cilia. The beat frequency increased over a range of concentration of Ca2+ from 2 X 10(-7) to 4 X 10(-7) M, in which the model swam forwards. The frequency increased also above 10(-6)M-Ca2+, in which the model swam backwards. The increase in frequency was inhibited by calmodulin antagonists. Intracellular injection of a Ca2+ buffer giving a free Ca2+ concentration of 2 X 10(-7) to 5 X 10(-7) M in intact cells induced an increase in the beat frequency. Therefore, it is very likely that the beat frequency of cilia is regulated by the intracellular concentration of Ca2+. PMID:6715425

  19. Amusic does not mean unmusical: beat perception and synchronization ability despite pitch deafness.

    PubMed

    Phillips-Silver, Jessica; Toiviainen, Petri; Gosselin, Nathalie; Peretz, Isabelle

    2013-01-01

    Pitch deafness, the most commonly known form of congenital amusia, refers to a severe deficit in musical pitch processing (i.e., melody discrimination and recognition) that can leave time processing--including rhythm, metre, and "feeling the beat"--preserved. In Experiment 1, we show that by presenting musical excerpts in nonpitched drum timbres, rather than pitched piano tones, amusics show normal metre recognition. Experiment 2 reveals that body movement influences amusics' interpretation of the beat of an ambiguous drum rhythm. Experiment 3 and a subsequent exploratory study show an ability to synchronize movement to the beat of popular dance music and potential for improvement when given a modest amount of practice. Together the present results are consistent with the idea that rhythm and beat processing are spared in pitch deafness--that is, being pitch-deaf does not mean one is beat-deaf. In the context of drum music especially, amusics can be musical. PMID:24344816

  20. Beating heart mitral valve repair with integrated ultrasound imaging

    NASA Astrophysics Data System (ADS)

    McLeod, A. Jonathan; Moore, John T.; Peters, Terry M.

    2015-03-01

    Beating heart valve therapies rely extensively on image guidance to treat patients who would be considered inoperable with conventional surgery. Mitral valve repair techniques including the MitrClip, NeoChord, and emerging transcatheter mitral valve replacement techniques rely on transesophageal echocardiography for guidance. These images are often difficult to interpret as the tool will cause shadowing artifacts that occlude tissue near the target site. Here, we integrate ultrasound imaging directly into the NeoChord device. This provides an unobstructed imaging plane that can visualize the valve lea ets as they are engaged by the device and can aid in achieving both a proper bite and spacing between the neochordae implants. A proof of concept user study in a phantom environment is performed to provide a proof of concept for this device.

  1. Space-Time Localization and Registration on the Beating Heart

    PubMed Central

    Wood, Nathan A.; Waugh, Kevin; Liu, Tian Yu Tommy; Zenati, Marco A.; Riviere, Cameron N.

    2012-01-01

    This paper presents a framework for localizing a miniature epicardial crawling robot, HeartLander, on the beating heart using only 6-degree-of-freedom position measurements from an electromagnetic position tracker and a dynamic surface model of the heart. Using only this information, motion and observation models of the system are developed such that a particle filter can accurately estimate not only the location of the robot on the surface of the heart, but also the pose of the heart in the world coordinate frame as well as the current physiological phase of the heart. The presented framework is then demonstrated in simulation on a dynamic 3-D model of the human heart and a robot motion model which accurately mimics the behavior of the HeartLander robot. PMID:24511430

  2. Robotic Tissue Tracking for Beating Heart Mitral Valve Surgery

    PubMed Central

    Yuen, Shelten G.; Vasilyev, Nikolay V.; del Nido, Pedro J.; Howe, Robert D.

    2010-01-01

    The rapid motion of the heart presents a significant challenge to the surgeon during intracardiac beating heart procedures. We present a 3D ultrasound-guided motion compensation system that assists the surgeon by synchronizing instrument motion with the heart. The system utilizes the fact that certain intracardiac structures, like the mitral valve annulus, have trajectories that are largely constrained to translation along one axis. This allows the development of a real-time 3D ultrasound tissue tracker that we integrate with a 1 degree-of-freedom (DOF) actuated surgical instrument and predictive filter to devise a motion tracking system adapted to mitral valve annuloplasty. In vivo experiments demonstrate that the system provides highly accurate tracking (1.0 mm error) with 70% less error than manual tracking attempts. PMID:23973122

  3. Synchronization using environmental coupling in mercury beating heart oscillators

    NASA Astrophysics Data System (ADS)

    Singla, Tanu; Montoya, Fernando; Rivera, M.; Tajima, Shunsuke; Nakabayashi, Seiichiro; Parmananda, P.

    2016-06-01

    We report synchronization of Mercury Beating Heart (MBH) oscillators using the environmental coupling mechanism. This mechanism involves interaction of the oscillators with a common medium/environment such that the oscillators do not interact among themselves. In the present work, we chose a modified MBH system as the common environment. In the absence of coupling, this modified system does not exhibit self sustained oscillations. It was observed that, as a result of the coupling of the MBH oscillators with this common environment, the electrical and the mechanical activities of both the oscillators synchronized simultaneously. Experimental results indicate the emergence of both lag and the complete synchronization in the MBH oscillators. Simulations of the phase oscillators were carried out in order to better understand the experimental observations.

  4. Nonlinear pattern analysis of ventricular premature beats by mutual information

    NASA Technical Reports Server (NTRS)

    Osaka, M.; Saitoh, H.; Yokoshima, T.; Kishida, H.; Hayakawa, H.; Cohen, R. J.

    1997-01-01

    The frequency of ventricular premature beats (VPBs) has been related to the risk of mortality. However, little is known about the temporal pattern of occurrence of VPBs and its relationship to autonomic activity. Hence, we applied a general correlation measure, mutual information, to quantify how VPBs are generated over time. We also used mutual information to determine the correlation between VPB production and heart rate in order to evaluate effects of autonomic activity on VPB production. We examined twenty subjects with more than 3000 VPBs/day and simulated random time series of VPB occurrence. We found that mutual information values could be used to characterize quantitatively the temporal patterns of VPB generation. Our data suggest that VPB production is not random and VPBs generated with a higher value of mutual information may be more greatly affected by autonomic activity.

  5. Testing the Beat Frequency Model of Horizontal Branch Qpos

    NASA Astrophysics Data System (ADS)

    Hertz, Paul

    The beat frequency modulated accretion (BFMA) model requires strong correlations in the horizontal branch quasiperiodic oscillations (HBO) and low frequency noise (LFN) amplitudes on time scales <1 s as they are both carried by the same accreting clumps. But such correlations have not been observed on time scales <8 s. With RXTE individual HBOs will be detectable in GX5-1 at the 1-2 sigma level. Using an optimal filter we will measure the phase coherence, strength, and clustering length of individual HBOs and the overall shot rate. We will test for the correlations between HBO and LFN amplitude predicted by the BFMA model and constrain some of the free observable parameters in the model. Any HBO model must account for these properties.

  6. Metal MEMS Tools for Beating-heart Tissue Removal

    PubMed Central

    Gosline, Andrew H.; Vasilyev, Nikolay V.; Veeramani, Arun; Wu, MingTing; Schmitz, Greg; Chen, Rich; Arabagi, Veaceslav; del Nido, Pedro J.; Dupont, Pierre E.

    2013-01-01

    A novel robotic tool is proposed to enable the surgical removal of tissue from inside the beating heart. The tool is manufactured using a unique metal MEMS process that provides the means to fabricate fully assembled devices that incorporate micron-scale features in a millimeter scale tool. The tool is integrated with a steerable curved concentric tube robot that can enter the heart through the vasculature. Incorporating both irrigation and aspiration, the tissue removal system is capable of extracting substantial amounts of tissue under teleoperated control by first morselizing it and then transporting the debris out of the heart through the lumen of the robot. Tool design and robotic integration are described and ex vivo experimental results are presented. PMID:24232076

  7. Kuramoto transition in an ensemble of mercury beating heart systems.

    PubMed

    Verma, Dinesh Kumar; Singh, Harpartap; Parmananda, P; Contractor, A Q; Rivera, M

    2015-06-01

    We have studied, experimentally, the collective behavior of the electrically coupled autonomous Mercury Beating Heart (MBH) systems exhibiting the breathing mode, by varying both the coupling strength and the population size (from N = 3 to N = 16). For a fixed N, the electrical and the mechanical activities of the MBH systems achieve complete synchronization at different coupling strengths. The electrical activity of each MBH system is measured by the corresponding electrode potential (Ei = Vi). Additionally, the mechanical activity of each MBH oscillator is visually observed (snapshots and video clips). Subsequently, this activity is quantified by calculating the temporal variation in the area (Ai) of the Hg drop. As a result, the synchronization of the electrical (Ei = Vi) and the mechanical (Ai) activities can be measured. The extent of synchronization was quantified by employing the order parameter (r). Our experimental results are found to be in agreement with the Kuramoto theory. PMID:26117134

  8. Oxidized Cellulose with Different Carboxyl Content: Structure and Properties before and after Beating

    NASA Astrophysics Data System (ADS)

    Vendula, Hejlová; Miloslav, Milichovský

    Our recent studies concentrated in investigating influence of beating oxidized cellulose, with different carboxyl content, on changing their basic properties (degree of polymerization, WRV - water resistant value and X-ray diffraction). Cellulose samples of oxidized cellulose were beated by toroidal beating machine. Cellulose consists of both amorphous and crystalline regions. Cellulose consists of linear chains of poly[ß-1,4-D- anhydroglucopyranose] (C6nH10n + 2O5n + 1 (n = degree of polymerization of glucose)), which crystallize through hydrogen bonding between the chains and has cellobiose as repeat unit. Oxidized cellulose is preparing by oxidation of cellulose in the C6 position of the glucopyranose units to carboxylic group (-COOH) and polyanhydroglukuronic acid (PAGA) is arised. An other option is oxidation with sodium hypochlorite with catalytic amounts of sodium bromide and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) under various conditions. Beating and refining or mechanical treatment of fibers in water is an important step in using pulps for papermaking. It is an energy intensive process. The purpose of the treatment is to modify fiber properties to obtain the most desirable paper machine runnability and product properties. End of beating pulps was characterized by position, when all beated pulps under mixture passed through of riddle (about sizes mesh of 50). During beating of samples about different ratio of oxidation it was found, that samples with higher contents of COOH groups in starting pulp are characterized by a significantly lower specific beating energy consumption needed to achieving the same sizes of particles. X-ray analyse shows that for non-beated oxidized cellulose was perceptible high share amorphous contents compared with beated oxidized cellulose.

  9. Beating polymer gels coupled with a nonlinear chemical reaction

    NASA Astrophysics Data System (ADS)

    Yoshida, Ryo; Kokufuta, Etsuo; Yamaguchi, Tomohiko

    1999-06-01

    We report on a beating polymer gel that exhibits periodical volume changes (swelling and deswelling) in a closed solution without external stimuli, like autonomous heartbeat. The mechanical oscillation is driven by the chemical energy of the oscillatory Belousov-Zhabotinsky (BZ) reaction. The gel is a copolymer gel of N-isopropylacrylamide (NIPAAm) in which ruthenium tris(2,2'-bipyridine) [Ru(bpy)3], known as a catalyst of the BZ reaction, is covalently bonded to the polymer chain. The poly[NIPAAm-co-Ru(bpy)3] gel provides an open system where the BZ reaction proceeds, when immersed in an aqueous solution containing the reactants of the BZ reaction (with the exception of a catalyst). The chemical oscillation in the BZ reaction generates the periodical changes of the charge of Ru(bpy)3 in the gel network between reduced [Ru(II)] and oxidized [Ru(III)] states. The gel swells at the oxidized state because the hydrophilicity of the polymer chains increases, while at the reduced state the gel deswells. Thus, the chemical energy is transduced into the mechanical energy to drive the polymer gel oscillation with a period of about 5 min, depending on the composition of the surrounding solution. The oscillation mode of the gel depends on its size scaled by the wavelength of the BZ pattern. Sufficiently small bead-like gels demonstrate isotropic beating. A large rectangular gel shows mechanical oscillation with a peristaltic motion coupled with the propagating chemical waves. The dynamic behavior of the chemical and mechanical oscillations have been analyzed with a model simulation.

  10. Viral skin diseases of the rabbit.

    PubMed

    Meredith, Anna L

    2013-09-01

    This article describes the viral skin diseases affecting the domestic rabbit, the most important being myxomatosis. Transmission and pathogenesis, clinical signs, diagnosis, treatment, and control are described and the article will be of interest to veterinary practitioners who treat rabbits. Shope fibroma virus, Shope papilloma virus, and rabbitpox are also discussed. PMID:24018033

  11. Rabbit models for continuous curvilinear capsulorhexis instruction

    PubMed Central

    Ruggiero, Jason; Keller, Christopher; Porco, Travis; Naseri, Ayman; Sretavan, David W.

    2012-01-01

    PURPOSE To develop a rabbit model for continuous curvilinear capsulorhexis (CCC) instruction. SETTING University of California San Francisco, San Francisco, California, USA. DESIGN Experimental study. METHODS Isolated rabbit lenses were immersed in 2% to 8% paraformaldehyde (PFA) fixative from 15 minutes to 6 hours. Rabbit eyes were treated by substituting aqueous with 2% to 4% PFA for 30 minutes to 6 hours, followed by washes with a balanced salt solution. Treated lenses and eyes were held in purpose-designed holders using vacuum. A panel of 6 cataract surgeons with 5 to 15 years of experience performed CCC on treated lenses and eyes and responded to a questionnaire regarding the utility of these models for resident teaching using a 5-item Likert scale. RESULTS The expert panel found that rabbit lenses treated with increasing amounts of fixative simulated CCC on human lens capsules from the third to the seventh decade of life. The panel also found fixative-treated rabbit eyes to simulate some of the experience of CCC within the human anterior chamber but noted a shallower anterior chamber depth, variation in pupil size, and corneal clouding under some treatment conditions. CONCLUSIONS Experienced cataract surgeons who performed CCC on these rabbit models strongly agreed that isolated rabbit lenses treated with fixative provide a realistic simulation of CCC in human patients and that both models were useful tools for capsulorhexis instruction. Results indicate that rabbit lenses treated with 8% PFA for 15 minutes is a model with good fidelity for CCC training. PMID:22727296

  12. Fluorodeoxyglucose rate constants, lumped constant, and glucose metabolic rate in rabbit heart

    SciTech Connect

    Krivokapich, J.; Huang, S.C.; Selin, C.E.; Phelps, M.E.

    1987-04-01

    The isolated arterial perfused rabbit interventricular septum was used to measure myocardial metabolic rate for glucose (MMRGlc) and rate constants and lumped constant (LC) for the glucose analogue (/sup 18/F)fluorodeoxyglucose (FDG) using a tracer kinetic model. FDG was delivered by constant infusion during coincidence counting of tissue /sup 18/F radioactivity. The MMRGlc was measured by the Fick method. Control septa were paced at 72 beats/min and perfused at 1.5 ml/min with oxygenated perfusate containing 5.6 mM glucose and 5 mU/ml insulin. The following conditions were tested: 3.0 and 4.5 ml/min; insulin increased to 25 mU/ml; insulin omitted; 2.8 mM and 11.2 mM glucose; 144 beats/min and 96 paired stimuli/min; and anoxia. Under all conditions studied the phosphorylation (hexokinase) reaction was rate limiting relative to transport. Compared with control conditions, the phosphorylation rate constant was significantly increased with 2.8 mM glucose as well as in anoxia. With 4.5 ml/min and 11.2 mM glucose, conditions that should increase glucose flux into tissue without increasing demand, the phosphorylation rate constant decreased significantly. With 11.2 mM glucose, 96 paired stimuli/min, and anoxia without insulin, a significant increase in the hydrolysis rate of FDG 6-phosphate was observed and suggests that hydrolysis is also an important mechanism for regulating the MMRGlc. Increased transport rate constants were observed with increased flow rates, 96 paired stimuli/min, and anoxia at 96 beats/min. The LC was not significantly different from control in 11 of 14 conditions studied. Therefore, under most conditions in average LC can be used to calculate MMRGlc estimates.

  13. Thermal cataract formation in rabbits

    SciTech Connect

    Kramar, P.; Harris, C.; Guy, A.W.

    1987-01-01

    Intraocularly circulating hot water was used to produce cataracts in nine eyes of seven rabbits by maintaining their retrolental temperatures between 43 degrees C and 45 degrees C. A rapid rate of heating (1.3 degrees C/min) plus a sharp temperature gradient across the eye may have been contributing factors in the consistent production of cataracts at these temperatures. Biomicroscopy and light microscopy showed lens changes similar to those associated with acute exposure to microwave radiation. These findings support the assumption that microwave cataractogenesis is due to the local production of elevated temperatures.

  14. Synchronization of sinoatrial node pacemaker cell clocks and its autonomic modulation impart complexity to heart beating intervals Short title: Beating-rate variability of sinoatrial node cells

    PubMed Central

    Yaniv, Yael; Ahmet, Ismayil; Liu, Jie; Lyashkov, Alexey E.; Guiriba, Toni-Rose; Okamoto, Yosuke; Ziman, Bruce D.; Lakatta, Edward G.

    2014-01-01

    Background A reduction of complexity of heart-beat interval variability (BIV) that is associated with an increased morbidity and mortality in cardiovascular disease states is thought to derive from the balance of sympathetic and parasympathetic neural impulses to the heart. But rhythmic clock-like behavior intrinsic to pacemaker cells within the sinoatrial node (SAN) drives their beating, even in the absence of autonomic neural input. Objective To test how this rhythmic clock-like behavior intrinsic to pacemaker cells interacts with autonomic impulses to the heart-beat interval variability in vivo. Methods We analyzed BIV in the time and frequency domains and by fractal and entropy analyses: i) in vivo, when the brain input to the SAN is intact; ii) during autonomic denervation in vivo; iii) in isolated SAN tissue (i.e., in which the autonomic-neural input is completely absent); iv) in single pacemaker cells isolated from the SAN; and v) following autonomic receptor stimulation of these cells. Results Spontaneous-beating intervals of pacemaker cells residing within the isolated SAN tissue exhibit fractal-like behavior and have lower approximate entropy than in the intact heart. Isolation of pacemaker cells from SAN tissue, however, leads to a loss in the beating-interval order and fractal-like behavior. β adrenergic receptor stimulation of isolated pacemaker cells increases intrinsic clock synchronization, decreases their action potential period and increases system complexity. Conclusions Both the average-beating interval in vivo and beating interval complexity are conferred by the combined effects of clock periodicity intrinsic to pacemaker cells and their response to autonomic-neural input. PMID:24713624

  15. Contribution of ion currents to beat-to-beat variability of action potential duration in canine ventricular myocytes.

    PubMed

    Szentandrássy, Norbert; Kistamás, Kornél; Hegyi, Bence; Horváth, Balázs; Ruzsnavszky, Ferenc; Váczi, Krisztina; Magyar, János; Bányász, Tamás; Varró, András; Nánási, Péter P

    2015-07-01

    Although beat-to-beat variability (short-term variability, SV) of action potential duration (APD) is considered as a predictor of imminent cardiac arrhythmias, the underlying mechanisms are still not clear. In the present study, therefore, we aimed to determine the role of the major cardiac ion currents, APD, stimulation frequency, and changes in the intracellular Ca(2+) concentration ([Ca(2+)]i) on the magnitude of SV. Action potentials were recorded from isolated canine ventricular cardiomyocytes using conventional microelectrode techniques. SV was an exponential function of APD, when APD was modified by current injections. Drug effects were characterized as relative SV changes by comparing the drug-induced changes in SV to those in APD according to the exponential function obtained with current pulses. Relative SV was increased by dofetilide, HMR 1556, nisoldipine, and veratridine, while it was reduced by BAY K8644, tetrodotoxin, lidocaine, and isoproterenol. Relative SV was also increased by increasing the stimulation frequency and [Ca(2+)]i. In summary, relative SV is decreased by ion currents involved in the negative feedback regulation of APD (I Ca, I Ks, and I Kr), while it is increased by I Na and I to. We conclude that drug-induced effects on SV should be evaluated in relation with the concomitant changes in APD. Since relative SV was decreased by ion currents playing critical role in the negative feedback regulation of APD, blockade of these currents, or the beta-adrenergic pathway, may carry also some additional proarrhythmic risk in addition to their well-known antiarrhythmic action. PMID:25081243

  16. Survival of rabid rabbits after intrathecal immunization.

    PubMed

    Kesdangsakonwut, Sawang; Sunden, Yuji; Aoshima, Keisuke; Iwaki, Yoshimi; Okumura, Masahiro; Sawa, Hirofumi; Umemura, Takashi

    2014-06-01

    Rabies is a fatal zoonotic disease for which no effective treatment measures are currently available. Rabies virus (RABV) has anti-apoptotic and anti-inflammatory properties that suppress nerve cell damage and inflammation in the CNS. These features imply that the elimination of RABV from the CNS by appropriate treatment could lead to complete recovery from rabies. Ten rabbits showing neuromuscular symptoms of rabies after subcutaneous (SC) immunization using commercially available vaccine containing inactivated whole RABV particles and subsequent fixed RABV (CVS strain) inoculation into hind limb muscles were allocated into three groups. Three rabbits received no further treatment (the SC group), three rabbits received three additional SC immunizations using the same vaccine, and four rabbits received three intrathecal (IT) immunizations, in which the vaccine was inoculated directly into the cerebrospinal fluid (the SC/IT group). An additional three naïve rabbits were inoculated intramuscularly with RABV and not vaccinated. The rabbits exhibited neuromuscular symptoms of rabies within 4-8 days post-inoculation (dpi) of RABV. All of the rabbits died within 8-12 dpi with the exception of one rabbit in the SC group and all four rabbits in SC/IT group, which recovered and started to respond to external stimuli at 11-18 dpi and survived until the end of the experimental period. RABV was eliminated from the CNS of the surviving rabbits. We report here a possible, although still incomplete, therapy for rabies using IT immunization. Our protocol may rescue the life of rabid patients and prompt the future development of novel therapies against rabies. PMID:24397792

  17. Survival of rabid rabbits after intrathecal immunization

    PubMed Central

    Kesdangsakonwut, Sawang; Sunden, Yuji; Aoshima, Keisuke; Iwaki, Yoshimi; Okumura, Masahiro; Sawa, Hirofumi; Umemura, Takashi

    2014-01-01

    Rabies is a fatal zoonotic disease for which no effective treatment measures are currently available. Rabies virus (RABV) has anti-apoptotic and anti-inflammatory properties that suppress nerve cell damage and inflammation in the CNS. These features imply that the elimination of RABV from the CNS by appropriate treatment could lead to complete recovery from rabies. Ten rabbits showing neuromuscular symptoms of rabies after subcutaneous (SC) immunization using commercially available vaccine containing inactivated whole RABV particles and subsequent fixed RABV (CVS strain) inoculation into hind limb muscles were allocated into three groups. Three rabbits received no further treatment (the SC group), three rabbits received three additional SC immunizations using the same vaccine, and four rabbits received three intrathecal (IT) immunizations, in which the vaccine was inoculated directly into the cerebrospinal fluid (the SC/IT group). An additional three naïve rabbits were inoculated intramuscularly with RABV and not vaccinated. The rabbits exhibited neuromuscular symptoms of rabies within 4–8 days post-inoculation (dpi) of RABV. All of the rabbits died within 8–12 dpi with the exception of one rabbit in the SC group and all four rabbits in SC/IT group, which recovered and started to respond to external stimuli at 11–18 dpi and survived until the end of the experimental period. RABV was eliminated from the CNS of the surviving rabbits. We report here a possible, although still incomplete, therapy for rabies using IT immunization. Our protocol may rescue the life of rabid patients and prompt the future development of novel therapies against rabies. PMID:24397792

  18. Ectopic beats in approximate entropy and sample entropy-based HRV assessment

    NASA Astrophysics Data System (ADS)

    Singh, Butta; Singh, Dilbag; Jaryal, A. K.; Deepak, K. K.

    2012-05-01

    Approximate entropy (ApEn) and sample entropy (SampEn) are the promising techniques for extracting complex characteristics of cardiovascular variability. Ectopic beats, originating from other than the normal site, are the artefacts contributing a serious limitation to heart rate variability (HRV) analysis. The approaches like deletion and interpolation are currently in use to eliminate the bias produced by ectopic beats. In this study, normal R-R interval time series of 10 healthy and 10 acute myocardial infarction (AMI) patients were analysed by inserting artificial ectopic beats. Then the effects of ectopic beats editing by deletion, degree-zero and degree-one interpolation on ApEn and SampEn have been assessed. Ectopic beats addition (even 2%) led to reduced complexity, resulting in decreased ApEn and SampEn of both healthy and AMI patient data. This reduction has been found to be dependent on level of ectopic beats. Editing of ectopic beats by interpolation degree-one method is found to be superior to other methods.

  19. Control of the ciliary beat by cyclic nucleotides in intact cortical sheets from Paramecium.

    PubMed

    Noguchi, Munenori; Kurahashi, Shotaro; Kamachi, Hiroyuki; Inoue, Hiroshi

    2004-12-01

    The locomotor behavior of Paramecium depends on the ciliary beat direction and beat frequency. Changes in the ciliary beat are controlled by a signal transduction mechanism that follows changes in the membrane potential. These events take place in cilia covered with a ciliary membrane. To determine the effects of second messengers in the cilia, cortical sheets were used with intact ciliary membrane as a half-closed system in which each cilium is covered with a ciliary membrane with an opening to the cell body. Cyclic nucleotides and their derivatives applied from an opening to the cell body affected the ciliary beat. cAMP and 8-Br-cAMP increased the beat frequency and the efficiency of propulsion and acted antagonistically to the action of Ca(2+). cGMP and 8-Br-cGMP increased the efficiency of propulsion accompanying clear metachronal waves but decreased the beat frequency. These results indicate that the cyclic nucleotides affect target proteins in the ciliary axonemes surrounded by the ciliary membrane without a membrane potential and increase the efficiency of propulsion of the ciliary beat. In vitro phosphorylation of isolated ciliary axonemes in the presence of cyclic nucleotides and their derivatives revealed that the action of cAMP was correlated with the phosphorylation of 29-kDa and 65-kDa proteins and that the action of cGMP was correlated with the phosphorylation of a 42-kDa protein. PMID:15613797

  20. Biomarkers and endogenous determinants of dofetilide-induced torsades de pointes in α1-adrenoceptor-stimulated, anaesthetized rabbits

    PubMed Central

    Farkas, Attila S; Rudas, László; Makra, Péter; Csík, Norbert; Leprán, István; Forster, Tamás; Csanády, Miklós; Papp, Julius Gy; Varró, András; Farkas, András

    2010-01-01

    BACKGROUND AND PURPOSE Torsades de pointes (TdP) liability is a stochastic event, which indicates that unidentified factors have an important role in facilitating the initiation of TdP by increasing the probability of TdP occurrence. We sought to identify factors that facilitate drug-induced TdP. EXPERIMENTAL APPROACH We studied dofetilide-induced TdP in pentobarbital-anaesthetized, phenylephrine-sensitized rabbits, seeking biomarkers that discriminated between the animals that experienced TdP (‘TdP+’ animals) and those that did not (‘TdP−’ animals). As novel variables, the beat-to-beat variability and instability of ECG intervals were measured at preset times, irrespective of whether or not hearts were in stable sinus rhythm (‘absolute’ variability and instability). Autonomic activity was also determined. KEY RESULTS Dofetilide delayed repolarization and induced arrhythmias prior to TdP. The variability of the coupling interval and shape of arrhythmic beats before TdP were significantly greater in the ‘TdP+’ group than in the ‘TdP−’ group. Accordingly, the ‘absolute’ variability and instability of the ECG intervals were significantly elevated in the ‘TdP+’ group. Phenylephrine increased significantly the up-baroreflex sensitivity in the ‘TdP+’ group before dofetilide administration. CONCLUSIONS AND IMPLICATIONS ‘Preceding’ arrhythmias have characteristics that permit prediction of TdP occurrence: the more chaotic the ventricular rhythm, the greater the probability of TdP initiation. This suggests that complexity of the arrhythmic beats may play an important mechanistic role in TdP genesis. The electrical instability quantified by the novel ‘absolute’ variability and instability parameters correlates with the probability of TdP occurrence. Baroreflex may contribute to TdP genesis in vivo. PMID:20659107

  1. Electron microscopic analysis of the specific granule content of human atria. An investigation of the role of atrial pressure and atrial rhythm in the release of atrial natriuretic peptide.

    PubMed

    Doubell, A F; Greeff, M P; Rossouw, D J; Weich, H F

    1990-08-18

    Knowledge about the stimulus for the release of atrial natriuretic peptide (ANP) from human atria is incomplete. Atrial stretch is known to be a stimulus and atrial tachyarrhythmias are thought to be another. The effects of atrial size (by two-dimensional echocardiography) and atrial fibrillation on the atrial specific granule content of human atria were studied to gain insight into the secretory mechanisms of ANP. An electron microscopic analysis of the atrial granule content was used to study 12 patients--5 with mitral stenosis and sinus rhythm, 3 with mitral stenosis and atrial fibrillation and 4 controls. Granules were counted using a free count and montage method. This is the first report of such a morphometric analysis in humans. Granule counts were significantly raised in the patients with mitral stenosis compared with controls (P less than 0.014). This observation probably reflects a high turnover state induced by elevated atrial pressures. Further support for this conclusion is provided by the demonstration of a positive correlation between granule counts and left atrial size (r = 0.86; P less than 0.01). The tendency for higher counts in patients with atrial fibrillation may be related to the rhythm disturbance itself, but clinical and echocardiographic data suggest more severe atrial pressure overload in this group. PMID:2143315

  2. Behavioral fever in newborn rabbits

    NASA Technical Reports Server (NTRS)

    Satinoff, E.; Mcewen, G. N., Jr.; Williams, B. A.

    1976-01-01

    New Zealand white rabbit pups aged 12 to 72 hr were divided into three groups and given an intraperitoneal injection of Pseudomonas polysaccharide, a saline vehicle alone, and no treatment, respectively. The animals injected with pyrogen and maintained at an ambient temperature of 32 C for 2 hr did not develop fever. When placed in a thermally graded alleyway, the animals injected with pyrogen selected gradient positions that represented significantly higher temperatures than controls injected with saline. Further stay at selected positions for 5 min caused a considerable increase in the rectal temperature of the pyrogen-injected pups but not that of controls. The results support the hypothesis that newborn rabbits will develop a fever by behavioral means after a single injection of an exogenous pyrogen if the opportunity for thermoregulatory behavior is present. No fever develops if the pups must rely solely on internal thermoregulatory mechanisms. The behavioral system for producing a fever is mature at birth, but an adequate system of internal reflexes does not appear to develop for some days.

  3. Disentangling beat perception from sequential learning and examining the influence of attention and musical abilities on ERP responses to rhythm.

    PubMed

    Bouwer, Fleur L; Werner, Carola M; Knetemann, Myrthe; Honing, Henkjan

    2016-05-01

    Beat perception is the ability to perceive temporal regularity in musical rhythm. When a beat is perceived, predictions about upcoming events can be generated. These predictions can influence processing of subsequent rhythmic events. However, statistical learning of the order of sounds in a sequence can also affect processing of rhythmic events and must be differentiated from beat perception. In the current study, using EEG, we examined the effects of attention and musical abilities on beat perception. To ensure we measured beat perception and not absolute perception of temporal intervals, we used alternating loud and soft tones to create a rhythm with two hierarchical metrical levels. To control for sequential learning of the order of the different sounds, we used temporally regular (isochronous) and jittered rhythmic sequences. The order of sounds was identical in both conditions, but only the regular condition allowed for the perception of a beat. Unexpected intensity decrements were introduced on the beat and offbeat. In the regular condition, both beat perception and sequential learning were expected to enhance detection of these deviants on the beat. In the jittered condition, only sequential learning was expected to affect processing of the deviants. ERP responses to deviants were larger on the beat than offbeat in both conditions. Importantly, this difference was larger in the regular condition than in the jittered condition, suggesting that beat perception influenced responses to rhythmic events in addition to sequential learning. The influence of beat perception was present both with and without attention directed at the rhythm. Moreover, beat perception as measured with ERPs correlated with musical abilities, but only when attention was directed at the stimuli. Our study shows that beat perception is possible when attention is not directed at a rhythm. In addition, our results suggest that attention may mediate the influence of musical abilities on beat

  4. The evolutionary neuroscience of musical beat perception: the Action Simulation for Auditory Prediction (ASAP) hypothesis

    PubMed Central

    Patel, Aniruddh D.; Iversen, John R.

    2013-01-01

    Every human culture has some form of music with a beat: a perceived periodic pulse that structures the perception of musical rhythm and which serves as a framework for synchronized movement to music. What are the neural mechanisms of musical beat perception, and how did they evolve? One view, which dates back to Darwin and implicitly informs some current models of beat perception, is that the relevant neural mechanisms are relatively general and are widespread among animal species. On the basis of recent neural and cross-species data on musical beat processing, this paper argues for a different view. Here we argue that beat perception is a complex brain function involving temporally-precise communication between auditory regions and motor planning regions of the cortex (even in the absence of overt movement). More specifically, we propose that simulation of periodic movement in motor planning regions provides a neural signal that helps the auditory system predict the timing of upcoming beats. This “action simulation for auditory prediction” (ASAP) hypothesis leads to testable predictions. We further suggest that ASAP relies on dorsal auditory pathway connections between auditory regions and motor planning regions via the parietal cortex, and suggest that these connections may be stronger in humans than in non-human primates due to the evolution of vocal learning in our lineage. This suggestion motivates cross-species research to determine which species are capable of human-like beat perception, i.e., beat perception that involves accurate temporal prediction of beat times across a fairly broad range of tempi. PMID:24860439

  5. See what I hear? Beat perception in auditory and visual rhythms.

    PubMed

    Grahn, Jessica A

    2012-07-01

    Our perception of time is affected by the modality in which it is conveyed. Moreover, certain temporal phenomena appear to exist in only one modality. The perception of temporal regularity or structure (e.g., the 'beat') in rhythmic patterns is one such phenomenon: visual beat perception is rare. The modality-specificity for beat perception is puzzling, as the durations that comprise rhythmic patterns are much longer than the limits of visual temporal resolution. Moreover, the optimization that beat perception provides for memory of auditory sequences should be equally relevant to visual sequences. Why does beat perception appear to be modality specific? One possibility is that the nature of the visual stimulus plays a role. Previous studies have usually used brief stimuli (e.g., light flashes) to present visual rhythms. In the current study, a rotating line that appeared sequentially in different spatial orientations was used to present a visual rhythm. Discrimination accuracy for visual rhythms and auditory rhythms was compared for different types of rhythms. The rhythms either had a regular temporal structure that previously has been shown to induce beat perception in the auditory modality, or they had an irregular temporal structure without beat-inducing qualities. Overall, the visual rhythms were discriminated more poorly than the auditory rhythms. The beat-based structure, however, increased accuracy for visual as well as auditory rhythms. These results indicate that beat perception can occur in the visual modality and improve performance on a temporal discrimination task, when certain types of stimuli are used. PMID:22623092

  6. 9 CFR 354.124 - Quarantine of diseased rabbits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Quarantine of diseased rabbits. 354... INSPECTION AND CERTIFICATION VOLUNTARY INSPECTION OF RABBITS AND EDIBLE PRODUCTS THEREOF Inspection Procedures; Ante-Mortem Inspections § 354.124 Quarantine of diseased rabbits. If live rabbits, which...

  7. BESNOITIA ORYCTOFELISI N. SP. (PROTOZOA: APICOMPLEXA) FROM DOMESTIC RABBITS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A species of Besnoitia from naturally infected rabbits from Argentina was propagated experimentally in mice, gerbils, rabbits, cats, and cell cultures. Cats fed tissue cysts from rabbits shed oocysts with a prepatent period of nine to 13 days. Sporulated oocysts were infective to gerbils, rabbits,...

  8. 9 CFR 354.124 - Quarantine of diseased rabbits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Quarantine of diseased rabbits. 354... INSPECTION AND CERTIFICATION VOLUNTARY INSPECTION OF RABBITS AND EDIBLE PRODUCTS THEREOF Inspection Procedures; Ante-Mortem Inspections § 354.124 Quarantine of diseased rabbits. If live rabbits, which...

  9. Structural design for birefringent holey fiber with a beat length insensitive to wavelength.

    PubMed

    Lin, Jian-Qiang; Shi, Zhi-Dong; Li, Ming-Jia; Chen, Hua

    2009-09-01

    By combination of two defect structures with positive and negative birefringence, we design a holey fiber with a beat length that is less sensitive to wavelength. The influence of different structural parameters on birefringence of holey fiber is calculated by the finite-difference beam propagation method. A stable beat length can be achieved at some given wavelength window by adjusting the parameters. An almost uniform beat length with a greater than 180 nm bandwidth at 1310 and 1550 nm wavelength windows is obtained, which is useful for the design and fabrication of fiber-optic wave plates with a wide band. PMID:19724314

  10. Beating pattern in quantum magnetotransport coefficients of spin-orbit coupled Dirac fermions in gated silicene

    NASA Astrophysics Data System (ADS)

    Firoz Islam, SK; Kanti Ghosh, Tarun

    2014-08-01

    We report a theoretical study of magnetotransport coefficients of spin-orbit coupled gated silicene in the presence and absence of spatial periodic modulation. The combined effect of spin-orbit coupling and perpendicular electric field manifests through the formation of a regular beating pattern in Weiss and SdH oscillations. Analytical results, in addition to the numerical results, of the beating pattern formation are provided. The analytical results yield a beating condition which will be useful to determine the spin-orbit coupling constant by simply counting the number of oscillation between any two successive nodes. Moreover, the numerical results of modulation effect on collisional and Hall conductivities are presented.

  11. Quantum beats in the field ionization of Rydberg atoms in the presence of magnetic fields

    NASA Astrophysics Data System (ADS)

    Gregoric, Vincent C.; Hastings, Hannah; Carroll, Thomas J.; Noel, Michael W.

    2016-05-01

    By exciting a coherent superposition and varying its phase evolution, quantum beats in the selective field ionization of Rydberg atoms have been observed. Here, we present a study exploring the effect of electric and magnetic fields on quantum beats. Beginning with a single excited state, a coherent superposition is created by a short electric field pulse in the presence of a static magnetic field. The resulting quantum beats are then observed in the field ionization spectrum. Additionally, millimeter-wave spectroscopy is used to probe the state populations in this superposition. This work is supported by the National Science Foundation under Grants No. 1205895 and No. 1205897.

  12. Dynamics of myocardial lactate efflux after a step in heart rate in isolated rabbit hearts.

    PubMed

    Hak, J B; van Beek, J H; van Wijhe, M H; Westerhof, N

    1993-12-01

    We investigated whether a glycolytic burst contributes to the initial adaptation of ATP synthesis to increased cardiac metabolic demand. Six isolated rabbit hearts were perfused with glucose-containing Tyrode solution at 28 degrees C. In venous and arterial samples the lactate concentration was determined with a sensitive enzymatic cycling method. After the heart rate was doubled from 60 to 120 beats/min, lactate efflux increased from 0.23 +/- 0.10 (SE) to 0.45 +/- 0.12 mumol.min-1.g-1 dry weight with a mean response time of 21.3 s but without an overshoot. The transport time for lactate is longer than 15.7 s, suggesting that lactate production adapts with a mean response time of less than 6 s. Because no overshoot in lactate efflux was found, it is unlikely that a glycolytic burst after a step in heart rate contributes to the fast adaptation of ATP synthesis to demand in the isolated rabbit heart, although it might be possible that a change in cytosolic lactate production is not reflected in an increase in lactate efflux. Extrapolation of the results of this study to the in vivo situation should be done with caution. PMID:8285247

  13. Hematologic comparisons of shot and live trapped cottontail rabbits.

    PubMed

    Jacobson, H A; Kirkpatrick, R L; Burkhart, H E; Davis, J W

    1978-01-01

    Comparisons were made between hematologic measurements of shot and box-trapped cottontail rabbits (Sylvilagus floridanus). Trapped rabbits had significantly (P less than 0.001) higher serum corticoid levels and segmented neutrophil percentages and significantly (P less than 0.001) lower lymphocyte percentages than did shot rabbits. Trapped rabbits also had significantly (P less than 0.05) higher packed cell volumes and blood urea nitrogen values than did shot rabbits. PMID:633520

  14. Bobcat attack on a cottontail rabbit

    USGS Publications Warehouse

    Biggins, D.E.; Biggins, D.M.

    2006-01-01

    We observed an attack by a bobcat (Lynx rufus) on a cottontail rabbit (Sylvilagus) that involved stealthy approach by the cat for >1 h, followed by a 12.3-s chase covering 116.0 m for the cat and 128.4 m for the rabbit. During the chase, the route of the cat from starting point to kill site was more direct than the semi-circular route of the rabbit. Stride lengths for the cat and total distance covered by the chase were longer than those previously reported for bobcats.

  15. Computerized image processing in the Reginald Denny beating trial

    NASA Astrophysics Data System (ADS)

    Morrison, Lawrence C.

    1997-02-01

    New image processing techniques may have significant benefits to law enforcement officials but need to be legally admissible in court. Courts have different tests for determining the admissibility of new scientific procedures, requiring their reliability to be established by expert testimony. The first test developed was whether there has been general acceptance of the new procedure within the scientific community. In 1993 the U.S. Supreme Court loosened the requirements for admissibility of new scientific techniques, although the California Supreme Court later retained the general acceptance test. What the proper standard is for admission of such evidence is important to both the technical community and to the legal community because of the conflict between benefits of rapidly developing technology, and the dangers of 'junk science.' The Reginald Denny beating case from the 1992 Los Angeles riots proved the value of computerized image processing in identifying persons committing crimes on videotape. The segmentation process was used to establish the presence of a tattoo on one defendant, which was key in his identification. Following the defendant's conviction, the California Court of Appeal approved the use of the evidence involving the segmentation process. This published opinion may be cited as legal precedent.

  16. Non-heart-beating organ donation in Italy.

    PubMed

    Geraci, P M; Sepe, V

    2011-06-01

    In 2007 the non-heart-beating organ donation (NHBD) "Programma Alba" (Sunrise Programme) started in Pavia, Italy. The initial plan was to cut down waiting list for kidney transplantation, while its final aim is to shorten organ transplantation waiting lists. When compared to European countries and the USA, the Italian NHBD program has taken longer to get established. Initially Italian physicians were not entirely aware of the NHBD organ viability for transplantation, furthermore ethical issues and the need to regulate medical requirements to Italian law slowed down the NHBD program. In particular, Italian legislation provides for death ascertainment after irreversible cardiac arrest, 20-minute flat electrocardiogram. This no-touch period is longer when compared to worldwide legislation, and organ viability has been a main concern for Italian transplant doctors over the years. However, recent data let up to 40-minute warm ischemia time to preserve organ viability; this has encouraged Pavia's group to establish the NHBD "Programma Alba". It was designed according to Italian legislation from death diagnosis to graft placement, from this perspective must the significant role of the Transplant coordinator be recognized. Since 2007 seven kidneys have been gathered from seven NHBD. Of these, six NHBD kidneys have been transplanted. Currently, four patients are out of dialysis. This report is a detailed description of NHBD "Programma Alba" and its preliminary results. PMID:21617625

  17. Coordinated Beating of Algal Flagella is Mediated by Basal Coupling

    NASA Astrophysics Data System (ADS)

    Wan, Kirsty; Goldstein, Raymond

    Cilia or flagella often exhibit synchronized behavior. This includes phase-locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and Rothschild of phase synchrony of nearby swimming spermatozoa, it has been a working hypothesis that synchrony arises from hydrodynamic interactions between beating filaments. Recent work on the dynamics of physically separated pairs of flagella isolated from the multicellular alga Volvox has shown that hydrodynamic coupling alone is sufficient for synchrony. However, the situation is more complex when considering multiple flagella on a single cell. We suggest that a mechanism, internal to the cell, provides an additional flagellar coupling. For instance, flagella of Chlamydomonas mutants deficient in filamentary connections between basal bodies are found to display markedly different synchronization from the wildtype. Diverse flagellar coordination strategies found in quadri-, octo- and hexadecaflagellates reveal further evidence that intracellular couplings between flagellar basal bodies compete with hydrodynamic interactions to determine the precise form of flagellar synchronization in unicellular algae.

  18. Automatic analysis of ciliary beat frequency using optical flow

    NASA Astrophysics Data System (ADS)

    Figl, Michael; Lechner, Manuel; Werther, Tobias; Horak, Fritz; Hummel, Johann; Birkfellner, Wolfgang

    2012-02-01

    Ciliary beat frequency (CBF) can be a useful parameter for diagnosis of several diseases, as e.g. primary ciliary dyskinesia. (PCD). CBF computation is usually done using manual evaluation of high speed video sequences, a tedious, observer dependent, and not very accurate procedure. We used the OpenCV's pyramidal implementation of the Lukas-Kanade algorithm for optical flow computation and applied this to certain objects to follow the movements. The objects were chosen by their contrast applying the corner detection by Shi and Tomasi. Discrimination between background/noise and cilia by a frequency histogram allowed to compute the CBF. Frequency analysis was done using the Fourier transform in matlab. The correct number of Fourier summands was found by the slope in an approximation curve. The method showed to be usable to distinguish between healthy and diseased samples. However there remain difficulties in automatically identifying the cilia, and also in finding enough high contrast cilia in the image. Furthermore the some of the higher contrast cilia are lost (and sometimes found) by the method, an easy way to distinguish the correct sub-path of a point's path have yet to be found in the case where the slope methods doesn't work.

  19. Small displacement measurements with subatomic resolution by beat frequency measurements

    NASA Astrophysics Data System (ADS)

    Cíp, O.; Petrů, F.; Buchta, Z.; Lazar, J.

    2007-07-01

    In this paper a novel method for high-resolution measurement of displacements with sub-atomic resolution is described. With this method, a length change of an optical resonator is directly transformed to a radio-frequency signal. A tunable He-Ne laser is locked to a mode of the resonator using a digital signal processing technique. Heterodyne mixing of this locked laser with an iodine-stabilized He-Ne laser converts the frequency of the laser locked to the cavity into the radio-frequency region. A HF counter measures the beat frequency from which the displacement can be derived directly. This method delivers inherent linearity and sub-nanometre resolution of the displacement over a range of several micrometres. An example of the capabilities of this system is given in this paper, where it is used for checking periodic deviations of a laser interferometer system. Emphasis is put on the construction of the optical resonator, on how its narrow resonance line-width is achieved, and how the required mechanical stability is achieved. The measurement range and the scale linearity are discussed in detail. Possible applications of this method are the calibration of nano-position systems based on PZT transducers, as well as inductive and capacitive sensors.

  20. Transport by Collective Flagellar Beating Facilitates Evolutionary Transitions to Multicellularity

    NASA Astrophysics Data System (ADS)

    Short, Martin; Powers, Thomas

    2005-11-01

    A central problem underlying the evolution from single cells to multicellular organisms is the relationship between metabolic requirements and environmental metabolite exchange with increasing size. For organisms that form spherical colonies such as the volvocalean green algae, there is a bottleneck if diffusion alone governs nutrient uptake as they increase in size, for the diffusive flux is linear in the radius while the requirements of surface somatic cells grow quadratically. Using Volvox as a model organism, we examine experimentally and theoretically the role that advection of fluid by surface flagella plays in enhancing nutrient uptake. We show that the fluid flow driven by the coordinated beating of those flagella produces a boundary layer in the concentration of a diffusing solute which renders the metabolite exchange rate quadratic in the colony radius. This bypasses the diffusive bottleneck, facilitating evolutionary transitions to multicellularity which may be driven by other environmental factors. These results suggest that flagella may have evolved not only for motility, but also to enhance metabolite exchange.

  1. Coordinated beating of algal flagella is mediated by basal coupling.

    PubMed

    Wan, Kirsty Y; Goldstein, Raymond E

    2016-05-17

    Cilia and flagella often exhibit synchronized behavior; this includes phase locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and Rothschild of phase synchrony of nearby swimming spermatozoa, it has been a working hypothesis that synchrony arises from hydrodynamic interactions between beating filaments. Recent work on the dynamics of physically separated pairs of flagella isolated from the multicellular alga Volvox has shown that hydrodynamic coupling alone is sufficient to produce synchrony. However, the situation is more complex in unicellular organisms bearing few flagella. We show that flagella of Chlamydomonas mutants deficient in filamentary connections between basal bodies display markedly different synchronization from the wild type. We perform micromanipulation on configurations of flagella and conclude that a mechanism, internal to the cell, must provide an additional flagellar coupling. In naturally occurring species with 4, 8, or even 16 flagella, we find diverse symmetries of basal body positioning and of the flagellar apparatus that are coincident with specific gaits of flagellar actuation, suggesting that it is a competition between intracellular coupling and hydrodynamic interactions that ultimately determines the precise form of flagellar coordination in unicellular algae. PMID:27140605

  2. Ultrasonic imaging of a beat-culture icon

    NASA Astrophysics Data System (ADS)

    Asmus, John F.; Witteman, Gregory J.

    1997-10-01

    Jay DeFeo's sculptural-painting was originally begun as a 'concept with a center'. This DeFeo work was pivotal to both her artistic recognition and development It epitomized the beat- culture's newly discovered creative freedoms encouraged during the art renaissance of the period that has come to be known as America's Chamelot. Jay DeFeo's Rose was the culmination of an almost ritualized performance-art process of creation and destruction that spanned the years 1958 through 1965 and resulted in a 0.4 X 2.5 X 3.2 meter, 100 kilogram composite-laminate painting/artifact. When the artwork begun to crumble twenty years ago it was totally encased in approximately 10cm of steel-reinforced plaster for structural support. Here we will describe the solids-imaging techniques considered and utilized in determining the painting's internal composition to aid in safe extraction of the artwork from its plaster tomb followed by complete restoration. Our imaging goals were first, locate the interior plaster-paint boundary and second, characterize the size, shape and relative geometry of voids and artifacts in the paint composite laminate to facilitate the positioning and embedding weight-bearing pins.

  3. Coordinated beating of algal flagella is mediated by basal coupling

    PubMed Central

    Wan, Kirsty Y.; Goldstein, Raymond E.

    2016-01-01

    Cilia and flagella often exhibit synchronized behavior; this includes phase locking, as seen in Chlamydomonas, and metachronal wave formation in the respiratory cilia of higher organisms. Since the observations by Gray and Rothschild of phase synchrony of nearby swimming spermatozoa, it has been a working hypothesis that synchrony arises from hydrodynamic interactions between beating filaments. Recent work on the dynamics of physically separated pairs of flagella isolated from the multicellular alga Volvox has shown that hydrodynamic coupling alone is sufficient to produce synchrony. However, the situation is more complex in unicellular organisms bearing few flagella. We show that flagella of Chlamydomonas mutants deficient in filamentary connections between basal bodies display markedly different synchronization from the wild type. We perform micromanipulation on configurations of flagella and conclude that a mechanism, internal to the cell, must provide an additional flagellar coupling. In naturally occurring species with 4, 8, or even 16 flagella, we find diverse symmetries of basal body positioning and of the flagellar apparatus that are coincident with specific gaits of flagellar actuation, suggesting that it is a competition between intracellular coupling and hydrodynamic interactions that ultimately determines the precise form of flagellar coordination in unicellular algae. PMID:27140605

  4. Beat (Beat Eating Disorders).

    PubMed

    2015-10-01

    This charity website provides a comprehensive range of information on eating disorders. There is an overview section about different types of eating disorders, which is in clear and easily understood terms, giving readers the option to seek more detailed information. PMID:26419568

  5. Short-term beat-to-beat variability of the QT interval is increased and correlates with parameters of left ventricular hypertrophy in patients with hypertrophic cardiomyopathy.

    PubMed

    Orosz, Andrea; Baczkó, István; Nagy, Viktória; Gavallér, Henriette; Csanády, Miklós; Forster, Tamás; Papp, Julius Gy; Varró, András; Lengyel, Csaba; Sepp, Róbert

    2015-09-01

    Stratification models for the prediction of sudden cardiac death (SCD) are inappropriate in patients with hypertrophic cardiomyopathy (HCM). We investigated conventional electrocardiogram (ECG) repolarization parameters and the beat-to-beat short-term QT interval variability (QT-STV), a new parameter of proarrhythmic risk, in 37 patients with HCM (21 males, average age 48 ± 15 years). Resting ECGs were recorded for 5 min and the frequency corrected QT interval (QTc), QT dispersion (QTd), beat-to-beat short-term variability of QT interval (QT-STV), and the duration of terminal part of T waves (Tpeak-Tend) were calculated. While all repolarization parameters were significantly increased in patients with HCM compared with the controls (QTc, 488 ± 61 vs. 434 ± 23 ms, p < 0.0001; QT-STV, 4.5 ± 2 vs. 3.2 ± 1 ms, p = 0.0002; Tpeak-Tend duration, 107 ± 27 vs. 91 ± 10 ms, p = 0.0015; QTd, 47 ± 17 vs. 34 ± 9 ms, p = 0.0002), QT-STV had the highest relative increase (+41%). QT-STV also showed the best correlation with indices of left ventricular (LV) hypertrophy, i.e., maximal LV wall thickness normalized for body surface area (BSA; r = 0.461, p = 0.004) or LV mass (determined by cardiac magnetic resonance imaging) normalized for BSA (r = 0.455, p = 0.015). In summary, beat-to-beat QT-STV showed the most marked increase in patients with HCM and may represent a novel marker that merits further testing for increased SCD risk in HCM. PMID:26313025

  6. American Idol's Randy Jackson He doesn't miss a beat controlling his diabete

    MedlinePlus

    ... Bar Home Current Issue Past Issues Special Section American Idol's Randy Jackson Past Issues / Winter 2008 Table ... a beat controlling his diabetes. Musician, producer, and American Idol judge Randy Jackson is a well-known ...

  7. Cardiomyocytes beat best on a matrix with heart-like elasticity -- Molecular mechanics of the changes

    NASA Astrophysics Data System (ADS)

    Carag, Christine; Engler, Adam; Discher, Dennis

    2009-03-01

    Cardiomyocytes derived from embryos beat spontaneously in culture, but it is shown here with a series of flexible substrates that matrices which mimic the elasticity of the developing heart are optimal for 1-Hz beating, for transmitting contractile work to the matrix, and for promoting actomyosin striation. On hard matrices that mechanically mimic a post-infarct fibrotic scar, cells overstrain themselves, lack striated myofibrils and stop beating; on very soft matrices, cells preserve contractile beating for days in culture but do very little work. Optimal matrix leads to a strain match between cell and matrix, and suggests dynamic differences in intracellular protein structures. A novel `cysteine shotgun' method of labeling the in situ proteome reveals differences in assembly or conformation of several abundant cytoskeletal proteins, including vimentin, filamin and myosin.

  8. Keynote Presentation: Genome Beat (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    ScienceCinema

    Zimmer, Carl [New York Times

    2013-01-22

    Carl Zimmer, a reporter for the New York Times, speaks on "The Genome Beat," the opening keynote presentation at the JGI User 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif

  9. "Keep the Beat" Healthy Blood Pressure Helps Prevent Heart Disease | NIH MedlinePlus the Magazine

    MedlinePlus

    ... Javascript on. Special Section: Healthy Blood Pressure "Keep the Beat": Healthy Blood Pressure Helps Prevent Heart Disease ... Contents Your blood pressure rises and falls during the day. But when it stays elevated over time, ...

  10. Free-electron laser from wave-mechanical beats of 2 electron beams

    NASA Technical Reports Server (NTRS)

    Lichtenstein, R. M.

    1982-01-01

    It is possible, though technically difficult, to produce beams of free electrons that exhibit beats of a quantum mechanical nature. (1) the generation of electromagnetic radiation, e.g., light, based on the fact that the beats give rise to alternating charge and current densities; and a frequency shifter, based on the fact that a beam with beats constitutes a moving grating. When such a grating is exposed to external radiation of suitable frequency and direction, the reflected rediation will be shifted in frequency, since the grating is moving. A twofold increase of the frequency is readily attainable. It is shown that it is impossible to generate radiation, because the alternating electromagnetic fields that accompany the beats cannot reform themselves into freely propagating waves. The frequency shifter is useless as a practical device, because its reflectance is extremely low for realizable beams.

  11. Beat synchronization predicts neural speech encoding and reading readiness in preschoolers.

    PubMed

    Woodruff Carr, Kali; White-Schwoch, Travis; Tierney, Adam T; Strait, Dana L; Kraus, Nina

    2014-10-01

    Temporal cues are important for discerning word boundaries and syllable segments in speech; their perception facilitates language acquisition and development. Beat synchronization and neural encoding of speech reflect precision in processing temporal cues and have been linked to reading skills. In poor readers, diminished neural precision may contribute to rhythmic and phonological deficits. Here we establish links between beat synchronization and speech processing in children who have not yet begun to read: preschoolers who can entrain to an external beat have more faithful neural encoding of temporal modulations in speech and score higher on tests of early language skills. In summary, we propose precise neural encoding of temporal modulations as a key mechanism underlying reading acquisition. Because beat synchronization abilities emerge at an early age, these findings may inform strategies for early detection of and intervention for language-based learning disabilities. PMID:25246562

  12. The molecular trigger for high-speed wing beats in a bee.

    PubMed

    Iwamoto, H; Yagi, N

    2013-09-13

    The high-frequency wing beat of higher-order insects is driven by self-sustained oscillations of constantly activated flight muscles. However, whether its underlying mechanism is based on flight muscle-specific features or on preexisting contractile functions is unknown. Here, we recorded X-ray diffraction movies, at a rate of 5000 frames/second, simultaneously from the two antagonistic flight muscles of bumblebees during wing beat. Signals that occurred at the right timing for triggering each wing-beat stroke were resolved in both muscles. The signals likely reflect stretch-induced myosin deformation, which would also enhance force in vertebrate muscles. The results suggest that insects use a refined preexisting force-enhancing mechanism for high-frequency wing beat, rather than developing a novel mechanism. PMID:23970560

  13. Keynote Presentation: Genome Beat (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    SciTech Connect

    Zimmer, Carl

    2012-03-20

    Carl Zimmer, a reporter for the New York Times, speaks on "The Genome Beat," the opening keynote presentation at the JGI User 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif

  14. Beat synchronization predicts neural speech encoding and reading readiness in preschoolers

    PubMed Central

    Woodruff Carr, Kali; White-Schwoch, Travis; Tierney, Adam T.; Strait, Dana L.; Kraus, Nina

    2014-01-01

    Temporal cues are important for discerning word boundaries and syllable segments in speech; their perception facilitates language acquisition and development. Beat synchronization and neural encoding of speech reflect precision in processing temporal cues and have been linked to reading skills. In poor readers, diminished neural precision may contribute to rhythmic and phonological deficits. Here we establish links between beat synchronization and speech processing in children who have not yet begun to read: preschoolers who can entrain to an external beat have more faithful neural encoding of temporal modulations in speech and score higher on tests of early language skills. In summary, we propose precise neural encoding of temporal modulations as a key mechanism underlying reading acquisition. Because beat synchronization abilities emerge at an early age, these findings may inform strategies for early detection of and intervention for language-based learning disabilities. PMID:25246562

  15. Keep the Beat Recipes - Chicken and Mushroom Fricassee | NIH MedlinePlus the Magazine

    MedlinePlus

    ... Javascript on. Special Section: Healthy Blood Pressure Keep the Beat Recipes Past Issues / Winter 2010 Table of ... and Blood Institute To Improve Blood Pressure, Try the DASH Diet If you're one of the ...

  16. Quantum beats in conductance oscillations in graphene-based asymmetric double velocity wells and electrostatic wells

    SciTech Connect

    Liu, Lei; Li, Yu-Xian; Zhang, Ying-Tao; Liu, Jian-Jun

    2014-01-14

    The transport properties in graphene-based asymmetric double velocity well (Fermi velocity inside the well less than that outside the well) and electrostatic well structures are investigated using the transfer matrix method. The results show that quantum beats occur in the oscillations of the conductance for asymmetric double velocity wells. The beating effect can also be found in asymmetric double electrostatic wells, but only if the widths of the two wells are different. The beat frequency for the asymmetric double well is exactly equal to the frequency difference between the oscillation rates in two isolated single wells with the same structures as the individual wells in the double well structure. A qualitative interpretation is proposed based on the fact that the resonant levels depend upon the sizes of the quantum wells. The beating behavior can provide a new way to identify the symmetry of double well structures.

  17. The Effect of Dopaminergic Medication on Beat-Based Auditory Timing in Parkinson's Disease.

    PubMed

    Cameron, Daniel J; Pickett, Kristen A; Earhart, Gammon M; Grahn, Jessica A

    2016-01-01

    Parkinson's disease (PD) adversely affects timing abilities. Beat-based timing is a mechanism that times events relative to a regular interval, such as the "beat" in musical rhythm, and is impaired in PD. It is unknown if dopaminergic medication influences beat-based timing in PD. Here, we tested beat-based timing over two sessions in participants with PD (OFF then ON dopaminergic medication) and in unmedicated control participants. People with PD and control participants completed two tasks. The first was a discrimination task in which participants compared two rhythms and determined whether they were the same or different. Rhythms either had a beat structure (metric simple rhythms) or did not (metric complex rhythms), as in previous studies. Discrimination accuracy was analyzed to test for the effects of beat structure, as well as differences between participants with PD and controls, and effects of medication (PD group only). The second task was the Beat Alignment Test (BAT), in which participants listened to music with regular tones superimposed, and responded as to whether the tones were "ON" or "OFF" the beat of the music. Accuracy was analyzed to test for differences between participants with PD and controls, and for an effect of medication in patients. Both patients and controls discriminated metric simple rhythms better than metric complex rhythms. Controls also improved at the discrimination task in the second vs. first session, whereas people with PD did not. For participants with PD, the difference in performance between metric simple and metric complex rhythms was greater (sensitivity to changes in simple rhythms increased and sensitivity to changes in complex rhythms decreased) when ON vs. OFF medication. Performance also worsened with disease severity. For the BAT, no group differences or effects of medication were found. Overall, these findings suggest that timing is impaired in PD, and that dopaminergic medication influences beat-based and non-beat

  18. Finding the beat: a neural perspective across humans and non-human primates.

    PubMed

    Merchant, Hugo; Grahn, Jessica; Trainor, Laurel; Rohrmeier, Martin; Fitch, W Tecumseh

    2015-03-19

    Humans possess an ability to perceive and synchronize movements to the beat in music ('beat perception and synchronization'), and recent neuroscientific data have offered new insights into this beat-finding capacity at multiple neural levels. Here, we review and compare behavioural and neural data on temporal and sequential processing during beat perception and entrainment tasks in macaques (including direct neural recording and local field potential (LFP)) and humans (including fMRI, EEG and MEG). These abilities rest upon a distributed set of circuits that include the motor cortico-basal-ganglia-thalamo-cortical (mCBGT) circuit, where the supplementary motor cortex (SMA) and the putamen are critical cortical and subcortical nodes, respectively. In addition, a cortical loop between motor and auditory areas, connected through delta and beta oscillatory activity, is deeply involved in these behaviours, with motor regions providing the predictive timing needed for the perception of, and entrainment to, musical rhythms. The neural discharge rate and the LFP oscillatory activity in the gamma- and beta-bands in the putamen and SMA of monkeys are tuned to the duration of intervals produced during a beat synchronization-continuation task (SCT). Hence, the tempo during beat synchronization is represented by different interval-tuned cells that are activated depending on the produced interval. In addition, cells in these areas are tuned to the serial-order elements of the SCT. Thus, the underpinnings of beat synchronization are intrinsically linked to the dynamics of cell populations tuned for duration and serial order throughout the mCBGT. We suggest that a cross-species comparison of behaviours and the neural circuits supporting them sets the stage for a new generation of neurally grounded computational models for beat perception and synchronization. PMID:25646516

  19. GENERAL: Stochastic Alternating Dynamics for Synchronous EAD-Like Beating Rhythms in Cultured Cardiac Myocytes

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Zhang, Hui-Min; Liu, Zhi-Qiang; Ding, Xue-Li; Yang, Ming-Hao; Gu, Hua-Guang; Ren, Wei

    2009-11-01

    Dissolved cardiac myocytes can couple together and generate synchronous beatings in culture. We observed a synchronized early after-depolarization(EAD)-like rhythm in cultured cardiac myocytes and reproduced the experimental observation in a network mathematical model whose dynamics are close to a Hopf bifurcation. The mechanism for this EAD-like rhythm is attributed to noised-induced stochastic alternatings between the focus and the limit cycle. These results provide novel understandings for pathological heart rhythms like the early immature beatings.

  20. Symmetrization of a polygonal hollow-core vortex through beat-wave resonance.

    PubMed

    Ait Abderrahmane, Hamid; Siddiqui, Kamran; Vatistas, Georgios H; Fayed, Mohamed; Ng, Hoi Dick

    2011-05-01

    We report on the symmetrization phenomenon of a hollow-core vortex in shallow liquid conditions. This phenomenon accompanies the transition of m wave into (m+1) wave and involves a beat-wave resonance that mediates energy transfer between the background flow and the vortex core. It is shown that this beat wave has a frequency m/(m-1)times the frequency of the parent m wave. PMID:21728659

  1. Beat, modulational, and decay instabilities of a circularly polarized Alfven wave

    NASA Technical Reports Server (NTRS)

    Hollweg, Joseph V.

    1994-01-01

    A circulary polarized low-frequency electomagnetic pump wave propoagating along an ambient magnetic field is known to be unstable to the growth of several parallel-propagating parametric instabilties. If ion-cyclotron effects are retained in a two-fluid description, the dispersion relation is a sixth-order polynomial. We present a series of new analytical approximations to this dispersion relation. We emphasize new results for the beat instability that occurs as an interaction of the forward prpagating upper sideband with the backward propagating lower sideband. The nature of the beat instabitlity depends on beta = (v(sub sound)/v(sub A)(exp 2) and on the sense of polarization of the pump wave. The beat and decay instabilities can occur together if the pump is left-handed (i.e., ion resonant) and if beta is less than or approximately 1, but they cannot occur together if the pump is right-handed. For a left-handed pump the beat mode is the only instability if beta is greater than or approximately 1. If the pump is right-handed and beta is greater than or approximately 1, then the beat instability exists only when the pump amplitude exceeds a threshold value, and the beat will be the only instability if the pump amplitude is large enough to stabilize the modulational instability. If the pump is left-handed and beta is less than or approximately 1, then the beat mode is stabilized when the pump amplitude becomes sufficiently large. The beat instability primarily produces a forward propagating transverse wave in the upper sideband. Thus if beta is greater than or approximately 1, the instabilities considered here do not produce the backward propagating waves which are thought to affect turbulence and the evolution of cross helicity in the solar wind. New analytical results are presented also for the decay and modulational instabilites when beta is approximately equal to 1.

  2. Energetic considerations of ciliary beating and the advantage of metachronal coordination

    PubMed Central

    Gueron, Shay; Levit-Gurevich, Konstantin

    1999-01-01

    The internal mechanism of cilia is among the most ancient biological motors on an evolutionary scale. It produces beat patterns that consist of two phases: during the effective stroke, the cilium moves approximately as a straight rod, and during the recovery stroke, it rolls close to the surface in a tangential motion. It is commonly agreed that these two phases are designed for efficient functioning: the effective stroke encounters strong viscous resistance and generates thrust, whereas the recovery stroke returns the cilium to starting position while avoiding viscous resistance. Metachronal coordination between cilia, which occurs when many of them beat close to each other, is believed to be an autonomous result of the hydrodynamical interactions in the system. Qualitatively, metachronism is perceived as a way for reducing the energy expenditure required for beating. This paper presents a quantitative study of the energy expenditure of beating cilia, and of the energetic significance of metachronism. We develop a method for computing the work done by model cilia that beat in a viscous fluid. We demonstrate that for a single cilium, beating in water, the mechanical work done during the effective stroke is approximately five times the amount of work done during the recovery stroke. Investigation of multicilia configurations shows that having neighboring cilia beat metachronally is energetically advantageous and perhaps even crucial for multiciliary functioning. Finally, the model is used to approximate the number of dynein arm attachments that are likely to occur during the effective and recovery strokes of a beat cycle, predicting that almost all of the available dynein arms should participate in generating the motion. PMID:10535905

  3. Finding the beat: a neural perspective across humans and non-human primates

    PubMed Central

    Merchant, Hugo; Grahn, Jessica; Trainor, Laurel; Rohrmeier, Martin; Fitch, W. Tecumseh

    2015-01-01

    Humans possess an ability to perceive and synchronize movements to the beat in music (‘beat perception and synchronization’), and recent neuroscientific data have offered new insights into this beat-finding capacity at multiple neural levels. Here, we review and compare behavioural and neural data on temporal and sequential processing during beat perception and entrainment tasks in macaques (including direct neural recording and local field potential (LFP)) and humans (including fMRI, EEG and MEG). These abilities rest upon a distributed set of circuits that include the motor cortico-basal-ganglia–thalamo-cortical (mCBGT) circuit, where the supplementary motor cortex (SMA) and the putamen are critical cortical and subcortical nodes, respectively. In addition, a cortical loop between motor and auditory areas, connected through delta and beta oscillatory activity, is deeply involved in these behaviours, with motor regions providing the predictive timing needed for the perception of, and entrainment to, musical rhythms. The neural discharge rate and the LFP oscillatory activity in the gamma- and beta-bands in the putamen and SMA of monkeys are tuned to the duration of intervals produced during a beat synchronization–continuation task (SCT). Hence, the tempo during beat synchronization is represented by different interval-tuned cells that are activated depending on the produced interval. In addition, cells in these areas are tuned to the serial-order elements of the SCT. Thus, the underpinnings of beat synchronization are intrinsically linked to the dynamics of cell populations tuned for duration and serial order throughout the mCBGT. We suggest that a cross-species comparison of behaviours and the neural circuits supporting them sets the stage for a new generation of neurally grounded computational models for beat perception and synchronization. PMID:25646516

  4. Real-time optical gating for three-dimensional beating heart imaging

    NASA Astrophysics Data System (ADS)

    Taylor, Jonathan M.; Saunter, Christopher D.; Love, Gordon D.; Girkin, John M.; Henderson, Deborah J.; Chaudhry, Bill

    2011-11-01

    We demonstrate real-time microscope image gating to an arbitrary position in the cycle of the beating heart of a zebrafish embryo. We show how this can be used for high-precision prospective gating of fluorescence image slices of the moving heart. We also present initial results demonstrating the application of this technique to 3-D structural imaging of the beating embryonic heart.

  5. Rabbit Models for Studying Human Infectious Diseases

    PubMed Central

    Peng, Xuwen; Knouse, John A; Hernon, Krista M

    2015-01-01

    Using an appropriate animal model is crucial for mimicking human disease conditions, and various facets including genetics, anatomy, and pathophysiology should be considered before selecting a model. Rabbits (Oryctolagus cuniculus) are well known for their wide use in production of antibodies, eye research, atherosclerosis and other cardiovascular diseases. However, a systematic description of the rabbit as primary experimental models for the study of various human infectious diseases is unavailable. This review focuses on the human infectious diseases for which rabbits are considered a classic or highly appropriate model, including AIDS (caused by HIV1), adult T-cell leukemia–lymphoma (human T-lymphotropic virus type 1), papilloma or carcinoma (human papillomavirus) , herpetic stromal keratitis (herpes simplex virus type 1), tuberculosis (Mycobacterium tuberculosis), and syphilis (Treponema pallidum). In addition, particular aspects of the husbandry and care of rabbits used in studies of human infectious diseases are described. PMID:26678367

  6. Eyeblink conditioning in the developing rabbit

    PubMed Central

    Brown, Kevin L.; Woodruff-Pak, Diana S.

    2011-01-01

    Eyeblink classical conditioning in pre-weanling rabbits was examined in the present study. Using a custom lightweight headpiece and restrainer, New Zealand white littermates were trained once daily in 400 ms delay eyeblink classical conditioning from postnatal days (PD) 17–21 or PD 24–28. These ages were chosen because eyeblink conditioning emerges gradually over PD 17–24 in rats (Stanton, Freeman, & Skelton, 1992), another altricial species with neurodevelopmental features similar to those of rabbits. Consistent with well-established findings in rats, rabbits trained from PD 24–28 showed greater conditioning relative to littermates trained from PD 17–21. Both age groups displayed poor retention of eyeblink conditioning at retraining one month after acquisition. These findings are the first to demonstrate eyeblink conditioning in the developing rabbit. With further characterization of optimal conditioning parameters, this preparation may have applications to neurodevelopmental disease models as well as research exploring the ontogeny of memory. PMID:21953433

  7. Rabbit Models for Studying Human Infectious Diseases.

    PubMed

    Peng, Xuwen; Knouse, John A; Hernon, Krista M

    2015-12-01

    Using an appropriate animal model is crucial for mimicking human disease conditions, and various facets including genetics, anatomy, and pathophysiology should be considered before selecting a model. Rabbits (Oryctolagus cuniculus) are well known for their wide use in production of antibodies, eye research, atherosclerosis and other cardiovascular diseases. However, a systematic description of the rabbit as primary experimental models for the study of various human infectious diseases is unavailable. This review focuses on the human infectious diseases for which rabbits are considered a classic or highly appropriate model, including AIDS (caused by HIV1), adult T-cell leukemia-lymphoma (human T-lymphotropic virus type 1), papilloma or carcinoma (human papillomavirus) , herpetic stromal keratitis (herpes simplex virus type 1), tuberculosis (Mycobacterium tuberculosis), and syphilis (Treponema pallidum). In addition, particular aspects of the husbandry and care of rabbits used in studies of human infectious diseases are described. PMID:26678367

  8. Human cortical responses to slow and fast binaural beats reveal multiple mechanisms of binaural hearing.

    PubMed

    Ross, Bernhard; Miyazaki, Takahiro; Thompson, Jessica; Jamali, Shahab; Fujioka, Takako

    2014-10-15

    When two tones with slightly different frequencies are presented to both ears, they interact in the central auditory system and induce the sensation of a beating sound. At low difference frequencies, we perceive a single sound, which is moving across the head between the left and right ears. The percept changes to loudness fluctuation, roughness, and pitch with increasing beat rate. To examine the neural representations underlying these different perceptions, we recorded neuromagnetic cortical responses while participants listened to binaural beats at a continuously varying rate between 3 Hz and 60 Hz. Binaural beat responses were analyzed as neuromagnetic oscillations following the trajectory of the stimulus rate. Responses were largest in the 40-Hz gamma range and at low frequencies. Binaural beat responses at 3 Hz showed opposite polarity in the left and right auditory cortices. We suggest that this difference in polarity reflects the opponent neural population code for representing sound location. Binaural beats at any rate induced gamma oscillations. However, the responses were largest at 40-Hz stimulation. We propose that the neuromagnetic gamma oscillations reflect postsynaptic modulation that allows for precise timing of cortical neural firing. Systematic phase differences between bilateral responses suggest that separate sound representations of a sound object exist in the left and right auditory cortices. We conclude that binaural processing at the cortical level occurs with the same temporal acuity as monaural processing whereas the identification of sound location requires further interpretation and is limited by the rate of object representations. PMID:25008412

  9. Neural responses to sounds presented on and off the beat of ecologically valid music.

    PubMed

    Tierney, Adam; Kraus, Nina

    2013-01-01

    The tracking of rhythmic structure is a vital component of speech and music perception. It is known that sequences of identical sounds can give rise to the percept of alternating strong and weak sounds, and that this percept is linked to enhanced cortical and oscillatory responses. The neural correlates of the perception of rhythm elicited by ecologically valid, complex stimuli, however, remain unexplored. Here we report the effects of a stimulus' alignment with the beat on the brain's processing of sound. Human subjects listened to short popular music pieces while simultaneously hearing a target sound. Cortical and brainstem electrophysiological onset responses to the sound were enhanced when it was presented on the beat of the music, as opposed to shifted away from it. Moreover, the size of the effect of alignment with the beat on the cortical response correlated strongly with the ability to tap to a beat, suggesting that the ability to synchronize to the beat of simple isochronous stimuli and the ability to track the beat of complex, ecologically valid stimuli may rely on overlapping neural resources. These results suggest that the perception of musical rhythm may have robust effects on processing throughout the auditory system. PMID:23717268

  10. Caffeine restriction has no role in the management of patients with symptomatic idiopathic ventricular premature beats.

    PubMed Central

    Newby, D. E.; Neilson, J. M.; Jarvie, D. R.; Boon, N. A.

    1996-01-01

    OBJECTIVE: To assess the role of caffeine restriction in the management of patients with symptomatic idiopathic ventricular premature beats. DESIGN: A randomised, double blind, 6 week intervention trial incorporating dietary caffeine restriction, caffeinated coffee, and decaffeinated coffee. SETTING: Cardiac outpatient clinic. PATIENTS: 13 patients with symptomatic frequent idiopathic ventricular premature beats. MAIN OUTCOME MEASURES: Weekly measures of serum caffeine concentration, coffee consumption, visual analogue score of palpitations, and 24 hour ventricular premature beat frequency. RESULTS: The interventions achieved significant alterations in serum caffeine concentrations (P < 0.001) which correlated with coffee consumption (r = 0.70; P < 0.001). Visual analogue palpitation scores showed a small, but significant correlation with ventricular premature beat frequencies (r = 0.34; P = 0.003). However, there were no significant changes in palpitation scores or ventricular premature beat frequencies during the intervention weeks and no significant correlations were found between these variables and serum caffeine concentrations. CONCLUSIONS: Caffeine restriction has no role in the management of patients referred with symptomatic idiopathic ventricular premature beats. PMID:8983684

  11. A high-density EEG investigation into steady state binaural beat stimulation.

    PubMed

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carey, Anne-Marie; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others. PMID:22496862

  12. A High-Density EEG Investigation into Steady State Binaural Beat Stimulation

    PubMed Central

    Goodin, Peter; Ciorciari, Joseph; Baker, Kate; Carrey, Anne-Marie; Harper, Michelle; Kaufman, Jordy

    2012-01-01

    Binaural beats are an auditory phenomenon that has been suggested to alter physiological and cognitive processes including vigilance and brainwave entrainment. Some personality traits measured by the NEO Five Factor Model have been found to alter entrainment using pulsing light stimuli, but as yet no studies have examined if this occurs using steady state presentation of binaural beats for a relatively short presentation of two minutes. This study aimed to examine if binaural beat stimulation altered vigilance or cortical frequencies and if personality traits were involved. Thirty-one participants were played binaural beat stimuli designed to elicit a response at either the Theta (7 Hz) or Beta (16 Hz) frequency bands while undertaking a zero-back vigilance task. EEG was recorded from a high-density electrode cap. No significant differences were found in vigilance or cortical frequency power during binaural beat stimulation compared to a white noise control period. Furthermore, no significant relationships were detected between the above and the Big Five personality traits. This suggests a short presentation of steady state binaural beats are not sufficient to alter vigilance or entrain cortical frequencies at the two bands examined and that certain personality traits were not more susceptible than others. PMID:22496862

  13. Effect of depth beating on the fiber properties and enzymatic saccharification efficiency of softwood kraft pulp.

    PubMed

    Gao, Wenhua; Xiang, Zhouyang; Chen, Kefu; Yang, Rendang; Yang, Fei

    2015-01-01

    Commercial bleached softwood kraft pulp was mechanically fibrillated by a PFI-mill with beating revolution from 5000 to 30,000 r. The extent of fibrillating on the pulp was evaluated by beating degree, fiber morphological properties (fiber length, width, coarseness and curls index), water retention value (WRV) and physical properties of paper made from the pulp. Depth beating process significantly affected the pulp fibrillations as showed by the decreased fiber length and width as well as the SEM analysis, but the effects were limited after beating revolution of 15,000. Depth beating process also improved the total internal pore and inter-fibril surface areas as shown by the increased WRV values. Substrate enzymatic digestibility (SED) of beaten pulp at 5000 revolutions could reach 95% at cellulase loading of 15 FPU/g of glucan. After the enzymatic hydrolysis, the size of the pulp residues was reduced to micro-scale, and a relative uniform size distribution of the residues appeared at 10,000 r beating revolution. PMID:25965499

  14. Oritavancin Pharmacokinetics and Bone Penetration in Rabbits

    PubMed Central

    Ostiguy, Valerie; Cadieux, Cordelia; Malouin, Mireille; Belanger, Odette; Far, Adel Rafai; Parr, Thomas R.

    2015-01-01

    The pharmacokinetics and bone concentrations of oritavancin were investigated after a single intravenous dose was administered to rabbits. The pharmacokinetic profile of oritavancin in rabbits showed that it is rapidly distributed to bone tissues, with concentrations remaining stable for up to 168 h, the last measured time point. Based on these findings, further evaluation of oritavancin for the treatment of infections in bone tissues is warranted. PMID:26239977

  15. Photoacoustic endoscopic imaging of the rabbit mediastinum

    NASA Astrophysics Data System (ADS)

    Yang, Joon-Mo; Favazza, Christopher; Chen, Ruimin; Yao, Junjie; Cai, Xin; Li, Chiye; Maslov, Konstantin; Zhou, Qifa; Shung, K. Kirk; Wang, Lihong V.

    2013-03-01

    Like ultrasound endoscopy, photoacoustic endoscopy (PAE) could become a valuable addition to clinical practice due to its deep imaging capability. Results from our recent in vivo transesophageal endoscopic imaging study on rabbits demonstrate the technique's capability to image major organs in the mediastinal region, such as the lung, trachea, and cardiovascular systems. Here, we present various features from photoacoustic images from the mediastinal region of several rabbits and discuss possible clinical contributions of this technique and directions of future technology development.

  16. Genomic Analysis of Companion Rabbit Staphylococcus aureus

    PubMed Central

    Holmes, Mark A.; Harrison, Ewan M.; Fisher, Elizabeth A.; Graham, Elizabeth M.; Parkhill, Julian; Foster, Geoffrey; Paterson, Gavin K.

    2016-01-01

    In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections. PMID:26963381

  17. Complement activation induced by rabbit rheumatoid factor.

    PubMed Central

    Meyer, R R; Brown, J C

    1980-01-01

    Rabbit rheumatoid factor produced in animals by hyperimmunized with group C streptococcal vaccine activated guinea pig complement. Anti-streptococcal serum was fractionated by Sephacryl S-200 chromatography into excluded (19S) and included (7S) material and examined for hemolytic activity in a sensitive homologous hemolytic assay system. In the presence of complement, both 19S and 7S antistreptococcal serum fractions induced lysis of bovine (ox) erythrocytes coated with mildly reduced and carboxymethylated rabbit anti-erythrocyte immunoglobulin G. That rabbit rheumatoid factor was responsible for the observed hemolytic activity was substantiated by hemolytic inhibition assays. Significant inhibition of hemolysis was effected when antistreptococcal serum fractions were incubated in the presence of human immunoglobulin G, rabbit immunoglobulin G, and Fc, whereas, no inhibition was detected when the same fractions were tested in the presence of rabbit Fab or F(ab')2 fragments. Deaggregation of inhibitor preparations revealed a preferential reactivity of rheumatoid factor for rabbit immunoglobulin G. In addition to the rheumatoid factor-dependent hemolytic activity observed in humoral preparations, immunoglobulin G-specific antibody-forming cells in spleen and peripheral blood lymphocyte isolates were enumerated by plaque-forming cell assay. PMID:7399707

  18. Genomic Analysis of Companion Rabbit Staphylococcus aureus.

    PubMed

    Holmes, Mark A; Harrison, Ewan M; Fisher, Elizabeth A; Graham, Elizabeth M; Parkhill, Julian; Foster, Geoffrey; Paterson, Gavin K

    2016-01-01

    In addition to being an important human pathogen, Staphylococcus aureus is able to cause a variety of infections in numerous other host species. While the S. aureus strains causing infection in several of these hosts have been well characterised, this is not the case for companion rabbits (Oryctolagus cuniculus), where little data are available on S. aureus strains from this host. To address this deficiency we have performed antimicrobial susceptibility testing and genome sequencing on a collection of S. aureus isolates from companion rabbits. The findings show a diverse S. aureus population is able to cause infection in this host, and while antimicrobial resistance was uncommon, the isolates possess a range of known and putative virulence factors consistent with a diverse clinical presentation in companion rabbits including severe abscesses. We additionally show that companion rabbit isolates carry polymorphisms within dltB as described as underlying host-adaption of S. aureus to farmed rabbits. The availability of S. aureus genome sequences from companion rabbits provides an important aid to understanding the pathogenesis of disease in this host and in the clinical management and surveillance of these infections. PMID:26963381

  19. Probabilistic model-based approach for heart beat detection.

    PubMed

    Chen, Hugh; Erol, Yusuf; Shen, Eric; Russell, Stuart

    2016-09-01

    Nowadays, hospitals are ubiquitous and integral to modern society. Patients flow in and out of a veritable whirlwind of paperwork, consultations, and potential inpatient admissions, through an abstracted system that is not without flaws. One of the biggest flaws in the medical system is perhaps an unexpected one: the patient alarm system. One longitudinal study reported an 88.8% rate of false alarms, with other studies reporting numbers of similar magnitudes. These false alarm rates lead to deleterious effects that manifest in a lower standard of care across clinics. This paper discusses a model-based probabilistic inference approach to estimate physiological variables at a detection level. We design a generative model that complies with a layman's understanding of human physiology and perform approximate Bayesian inference. One primary goal of this paper is to justify a Bayesian modeling approach to increasing robustness in a physiological domain. In order to evaluate our algorithm we look at the application of heart beat detection using four datasets provided by PhysioNet, a research resource for complex physiological signals, in the form of the PhysioNet 2014 Challenge set-p1 and set-p2, the MIT-BIH Polysomnographic Database, and the MGH/MF Waveform Database. On these data sets our algorithm performs on par with the other top six submissions to the PhysioNet 2014 challenge. The overall evaluation scores in terms of sensitivity and positive predictivity values obtained were as follows: set-p1 (99.72%), set-p2 (93.51%), MIT-BIH (99.66%), and MGH/MF (95.53%). These scores are based on the averaging of gross sensitivity, gross positive predictivity, average sensitivity, and average positive predictivity. PMID:27480267

  20. Mode beating and heterodyning of monolithically integrated semiconductor ring lasers

    NASA Astrophysics Data System (ADS)

    Liu, Chiyu

    Monolithically integrated semiconductor ring lasers (SRLs) are attractive optical sources for optoelectronic integrated circuits (OEICs) because they do not require any feedback elements, do not have parts exposed to external ambient, and can operate in a traveling-wave mode. They are promising candidates for wavelength filtering, unidirectional traveling-wave operation, and multiplexing/demultiplexing applications. Ring lasers can also be used as ultrashort pulse generators using various mode-locking schemes and as active gyro components. However, the SRL is a very complicated dynamic system, which requires more investigations to understand the performance regarding details of the design and fabrication. As a part of NASA-supported project "Monolithically Integrated Semiconductor Ring Laser Gyro for Space Applications", this dissertation research was focused on design and characterization of a novel monolithically integrated rotation sensor based on two large-size independent SRLs. Numerical modeling based on the beam propagation method (BPM) was used to design the fabrication parameters for the single-mode ridge-waveguide ring cavity and directional coupler waveguides. The mode internal coupling in single lateral-mode laser diodes with InGaAs/GaAs material system was investigated by optical experiments and numerical modeling. To gain the understanding of the SRL performance, optical and electrical characterization was performed on fabricated SRLs. Particular emphasis was placed on the study of optical and radio frequency (RF) beating spectra of longitudinal modes of ring lasers. RF measurements provide high accuracy in the diagnosis of laser oscillation parameters by purely electronic means, particularly in the measurement of the group index and its dependence on current and temperature. Theoretical analysis based on the effective index method provides good agreement between the experimental data and numerical calculations. Finally, optical heterodyning spectra

  1. Ammonia excretion in mytilid mussels is facilitated by ciliary beating.

    PubMed

    Thomsen, J; Himmerkus, N; Holland, N; Sartoris, F J; Bleich, M; Tresguerres, M

    2016-08-01

    The excretion of nitrogenous waste products in the form of ammonia (NH3) and ammonium (NH4 (+)) is a fundamental process in aquatic organisms. For mytilid bivalves, little is known about the mechanisms and sites of excretion. This study investigated the localization and the mechanisms of ammonia excretion in mytilid mussels. An Rh protein was found to be abundantly expressed in the apical cell membrane of the plicate organ, which was previously described as a solely respiratory organ. The Rh protein was also expressed in the gill, although at significantly lower concentrations, but was not detectable in mussel kidney. Furthermore, NH3/NH4 (+) was not enriched in the urine, suggesting that kidneys are not involved in active NH3/NH4 (+) excretion. Exposure to elevated seawater pH of 8.5 transiently reduced NH3/NH4 (+) excretion rates, but they returned to control values following 24 h acclimation. These mussels had increased abundance of V-type H(+)-ATPase in the apical membranes of plicate organ cells; however, NH3/NH4 (+) excretion rates were not affected by the V-type H(+)-ATPase specific inhibitor concanamycin A (100 nmol l(-1)). In contrast, inhibition of ciliary beating with dopamine and increased seawater viscosity significantly reduced NH3 excretion rates under control pH (8.0). These results suggest that NH3/NH4 (+) excretion in mytilid mussels takes place by passive NH3 diffusion across respiratory epithelia via the Rh protein, facilitated by the water current produced for filter feeding, which prevents accumulation of NH3 in the boundary layer. This mechanism would be energy efficient for sessile organisms, as they already generate water currents for filter feeding. PMID:27489216

  2. The Effect of Dopaminergic Medication on Beat-Based Auditory Timing in Parkinson’s Disease

    PubMed Central

    Cameron, Daniel J.; Pickett, Kristen A.; Earhart, Gammon M.; Grahn, Jessica A.

    2016-01-01

    Parkinson’s disease (PD) adversely affects timing abilities. Beat-based timing is a mechanism that times events relative to a regular interval, such as the “beat” in musical rhythm, and is impaired in PD. It is unknown if dopaminergic medication influences beat-based timing in PD. Here, we tested beat-based timing over two sessions in participants with PD (OFF then ON dopaminergic medication) and in unmedicated control participants. People with PD and control participants completed two tasks. The first was a discrimination task in which participants compared two rhythms and determined whether they were the same or different. Rhythms either had a beat structure (metric simple rhythms) or did not (metric complex rhythms), as in previous studies. Discrimination accuracy was analyzed to test for the effects of beat structure, as well as differences between participants with PD and controls, and effects of medication (PD group only). The second task was the Beat Alignment Test (BAT), in which participants listened to music with regular tones superimposed, and responded as to whether the tones were “ON” or “OFF” the beat of the music. Accuracy was analyzed to test for differences between participants with PD and controls, and for an effect of medication in patients. Both patients and controls discriminated metric simple rhythms better than metric complex rhythms. Controls also improved at the discrimination task in the second vs. first session, whereas people with PD did not. For participants with PD, the difference in performance between metric simple and metric complex rhythms was greater (sensitivity to changes in simple rhythms increased and sensitivity to changes in complex rhythms decreased) when ON vs. OFF medication. Performance also worsened with disease severity. For the BAT, no group differences or effects of medication were found. Overall, these findings suggest that timing is impaired in PD, and that dopaminergic medication influences beat

  3. Serologic evidence for rabbit syncytium virus in eastern cottontail rabbits (Sylvilagus floridanus) in Ohio.

    PubMed

    Theil, K W; McCloskey, C M; Scott, D P

    1993-07-01

    Thirteen of 20 eastern cottontail rabbit (Sylvilagus floridanus) sera collected near Delaware, Ohio (USA) in 1991 were positive by indirect immunofluorescent antibody test (IFAT) for antibody to rabbit syncytium virus (RSV), a Kemerovo serogroup orbivirus. In addition, two of 10 domestic bovine sera and three of 30 sheep sera collected in southeastern Ohio gave weak positive IFAT reactions to RSV. PMID:8394944

  4. To beat or not to beat a tick: comparison of DNA extraction methods for ticks (Ixodes scapularis).

    PubMed

    Ammazzalorso, Alyssa D; Zolnik, Christine P; Daniels, Thomas J; Kolokotronis, Sergios-Orestis

    2015-01-01

    Background. Blacklegged ticks (Ixodes scapularis) are important disease vectors in the United States, known to transmit a variety of pathogens to humans, including bacteria, protozoa, and viruses. Their importance as a disease vector necessitates reliable and comparable methods for extracting microbial DNA from ticks. Furthermore, to explore the population genetics or genomics of this tick, appropriate DNA extraction techniques are needed for both the vector and its microbes. Although a few studies have investigated different methods of DNA isolation from ticks, they are limited in the number and types of DNA extraction and lack species-specific quantification of DNA yield. Methods. Here we determined the most efficient and consistent method of DNA extraction from two different developmental stages of I. scapularis-nymph and adult-that are the most important for disease transmission. We used various methods of physical disruption of the hard, chitinous exoskeleton, as well as commercial and non-commercial DNA isolation kits. To gauge the effectiveness of these methods, we quantified the DNA yield and confirmed the DNA quality via PCR of both tick and microbial genetic material. Results. DNA extraction using the Thermo GeneJET Genomic DNA Purification Kit resulted in the highest DNA yields and the most consistent PCR amplification when combined with either cutting or bead beating with select matrices across life stages. DNA isolation methods using ammonium hydroxide as well as the MoBio PowerSoil kit also produced strong and successful PCR amplification, but only for females. Discussion. We contrasted a variety of readily available methods of DNA extraction from single individual blacklegged ticks and presented the results through a quantitative and qualitative assessment. PMID:26290800

  5. Cross-cultural influences on rhythm processing: reproduction, discrimination, and beat tapping

    PubMed Central

    Cameron, Daniel J.; Bentley, Jocelyn; Grahn, Jessica A.

    2015-01-01

    The structures of musical rhythm differ between cultures, despite the fact that the ability to entrain movement to musical rhythm occurs in virtually all individuals across cultures. To measure the influence of culture on rhythm processing, we tested East African and North American adults on perception, production, and beat tapping for rhythms derived from East African and Western music. To assess rhythm perception, participants identified whether pairs of rhythms were the same or different. To assess rhythm production, participants reproduced rhythms after hearing them. To assess beat tapping, participants tapped the beat along with repeated rhythms. We expected that performance in all three tasks would be influenced by the culture of the participant and the culture of the rhythm. Specifically, we predicted that a participant’s ability to discriminate, reproduce, and accurately tap the beat would be better for rhythms from their own culture than for rhythms from another culture. In the rhythm discrimination task, there were no differences in discriminating culturally familiar and unfamiliar rhythms. In the rhythm reproduction task, both groups reproduced East African rhythms more accurately than Western rhythms, but East African participants also showed an effect of cultural familiarity, leading to a significant interaction. In the beat tapping task, participants in both groups tapped the beat more accurately for culturally familiar than for unfamiliar rhythms. Moreover, there were differences between the two participant groups, and between the two types of rhythms, in the metrical level selected for beat tapping. The results demonstrate that culture does influence the processing of musical rhythm. In terms of the function of musical rhythm, our results are consistent with theories that musical rhythm enables synchronization. Musical rhythm may foster musical cultural identity by enabling within-group synchronization to music, perhaps supporting social cohesion

  6. Meniscal allograft transplantation in rabbit.

    PubMed

    Vilela, Liana M; Del Carlo, Ricardo J; Melo Filho, Edson V; Favarato, Lukiya S C; Duarte, Tatiana S; Pontes, Kelly C S; Cunha, Daise N Q

    2015-01-01

    This study evaluated the technique for meniscal allograft transplantation using allografts preserved in glycerin 98% in rabbits. Euthanasia was performed at 70 days to compare the transplanted (TM1 to TM16) versus the contralateral meniscus (OM1 to OM16). Sixteen menisci, 8 transplanted and 8 contralateral, were submitted to gross examination, histomorphometric analysis for identification and quantification of cellular type, and for quantification and distribution of collagen fibers. A revascularization study was conducted in all of the other samples. Lengths of the OM varied from 0.9 to 1.0 cm and two TM were smaller. All TM were completely attached to the synovial membrane, except for one case that presented partial fixation. Both, TM and OM had similar amounts of chondrocytes, fibroblasts and fibrocytes, and at the horns, chondrocytes were predominant. The collagen fibers in TM were well organized throughout the body, and disorganized at the horns. These fibers in OM were organized. The amounts of collagen type I and III, and the vascularization of the perimeniscal tissue and of the edge were similar in OM and TM. These results demonstrated graft integration and thus this transplantation technique and preservation method may be recommended. PMID:26648544

  7. Phosphatidylinositol kinase from rabbit reticulocytes

    SciTech Connect

    Tuazon, P.T.; Heng, A.B.W.; Traugh, J.A.

    1986-05-01

    Phosphatidylinositol (PI) kinase was isolated from the postribosomal supernatant of rabbit reticulocytes. This activity was identified by the formation of a product that comigrated with phosphatidylinositol-4-phosphate (PIP) when purified PI was phosphorylated in the presence of (/sup 32/P)ATP and Mg/sup 2 +/. Three major peaks of PI kinase activity were resolved by chromatography on DEAE-cellulose. The first peak eluted at 50-100 mM NaCl together with several serine protein kinases, casein kinase (CK) I and protease activated kinase (PAK) I and II. The PI kinase was subsequently separated from the protein kinases by chromatography on phosphocellulose. The second peak eluted at 125-160 mM NaCl and contained another lipid kinase activity that produced a product which comigrated with phosphatidic acid on thin layer chromatography. The third peak, which eluted at 165-200 mM NaCl, partly comigrated with casein kinase (CK) II and an active protein kinase(s) which phosphorylated mixed histone and histone I. CK II and the histone kinase activities were also separated by chromatography on phosphocelluslose. The different forms of PI kinase were characterized and compared with respect to substrate and salt requirements.

  8. Ultrastructure of rabbit semilunar cartilages.

    PubMed Central

    Ghadially, F N; Thomas, I; Yong, N; Lalonde, J M

    1978-01-01

    A light and transmission electron microscopical study of 6 to 8 months old rabbit semilunar cartilages has shown that the cells in this tissue resemble chondrocytes more than fibroblasts. The prominent organelles in these cells were rough endoplasmic reticulum and the Golgi complex. An unusual finding was the occurrence of filamentous material in Golgi sacs and vesicles, and collagen fibrils within smooth membrane-bound tubular structures, apparently within the cells. Collagen fibrils forming fibres, fibre bundles and lamellae constituted the major component of the menisci. Protein-polysaccharide particles and associated fine filaments were found in the interfibrillary matrix and in the sparse territorial matrix adjacent to the chondrocytes. Numerous immature elastic fibrils, and rare mature elastic fibres with an electorn-lucent amorphous core, were also found in the general matrix amongst the collagen fibrils. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 PMID:580431

  9. Intracellular pathways regulating ciliary beating of rat brain ependymal cells

    PubMed Central

    Nguyen, Thien; Chin, Wei-Chun; O’Brien, Jennifer A; Verdugo, Pedro; Berger, Albert J

    2001-01-01

    The mammalian brain ventricles are lined with ciliated ependymal cells. As yet little is known about the mechanisms by which neurotransmitters regulate cilia beat frequency (CBF). Application of 5-HT to ependymal cells in cultured rat brainstem slices caused CBF to increase. 5-HT had an EC50 of 30 μM and at 100 μM attained a near-maximal CBF increase of 52.7 ± 4.1 % (mean ± s.d.) (n= 8). Bathing slices in Ca2+-free solution markedly reduced the 5-HT-mediated increase in CBF. Fluorescence measurements revealed that 5-HT caused a marked transient elevation in cytosolic Ca2+ ([Ca2+]c) that then slowly decreased to a plateau level. Analysis showed that the [Ca2+]c transient was due to release of Ca2+ from inositol 1,4,5-trisphosphate (IP3)-sensitive stores; the plateau was probably due to extracellular Ca2+ influx through Ca2+ release-activated Ca2+ (CRAC) channels. Application of ATP caused a sustained decrease in CBF. ATP had an EC50 of about 50 μM and 100 μM ATP resulted in a maximal 57.5 ± 6.5 % (n= 12) decrease in CBF. The ATP-induced decrease in CBF was unaffected by lowering extracellular [Ca2+], and no changes in [Ca2+]c were observed. Exposure of ependymal cells to forskolin caused a decrease in CBF. Ciliated ependymal cells loaded with caged cAMP exhibited a 54.3 ± 7.5 % (n= 9) decrease in CBF following uncaging. These results suggest that ATP reduces CBF by a Ca2+-independent cAMP-mediated pathway. Application of 5-HT and adenosine-5′-O-3-thiotriphosphate (ATP-γ-S) to acutely isolated ciliated ependymal cells resulted in CBF responses similar to those of ependymal cells in cultured slices suggesting that these neurotransmitters act directly on these cells. The opposite response of ciliated ependymal cells to 5-HT and ATP provides a novel mechanism for their active involvement in central nervous system signalling. PMID:11179397

  10. An electrophysiological study of the regulation of ciliary beating frequency in Paramecium.

    PubMed

    Brehm, P; Eckert, R

    1978-10-01

    1. The role of the surface membrane in the control of ciliary beat frequency in Paramecium was examined by intracellular electrophysiological techniques and pressure injection of Ca2+ and EGTA. Experiments were done on wild type P. caudatum and on both the wild type and a pawn mutant of P. tetraurelia. 2. The increased frequency of beating that accompanies reversal of power stroke orientation in response to depolarization in the wild type fails to occur during depolarization in the mutant pawn, which also fails to exhibit ciliary reversal upon depolarization. 3. Injection of moderate amounts of EGTA blocked the frequency increase without interfering with reversal of the beat in response to depolarization of the wild type. Larger injection of EGTA also prevented reversed beating. 4. The beat frequency in the normal (forward-swimming) direction increased during hyperpolarization in pawn. The hyperpolarizing frequency-voltage relations were quantitatively similar to those of the wild type. 5. Injection of EGTA to a final concentration of 10 mM into wild type cells neither modified the resting frequency nor blocked the frequency increase which normally accompanies hyperpolarization. 6. Transient ciliary reversal in both pawn and wild type produced by injection of Ca2+ could be terminated by the passage of inward current. The power stroke returned to the normal forward-swimming direction and the ciliary beating frequency increased. Upon termination of the inward current the cilia of Ca2+-injected cells again beat in reverse for many seconds. 7. The results support previous reports that increased frequency of beating and ciliary reversal seen in response to depolarization both require the entry of Ca2+ through the surface membrane. On the other hand, the results indicate that frequency increase with hyperpolarization is independent of an altered rate of Ca2+ entry. 8. Increased frequency during hyperpolarization appears to be related more closely to electrotonic membrane

  11. An electrophysiological study of the regulation of ciliary beating frequency in Paramecium.

    PubMed Central

    Brehm, P; Eckert, R

    1978-01-01

    1. The role of the surface membrane in the control of ciliary beat frequency in Paramecium was examined by intracellular electrophysiological techniques and pressure injection of Ca2+ and EGTA. Experiments were done on wild type P. caudatum and on both the wild type and a pawn mutant of P. tetraurelia. 2. The increased frequency of beating that accompanies reversal of power stroke orientation in response to depolarization in the wild type fails to occur during depolarization in the mutant pawn, which also fails to exhibit ciliary reversal upon depolarization. 3. Injection of moderate amounts of EGTA blocked the frequency increase without interfering with reversal of the beat in response to depolarization of the wild type. Larger injection of EGTA also prevented reversed beating. 4. The beat frequency in the normal (forward-swimming) direction increased during hyperpolarization in pawn. The hyperpolarizing frequency-voltage relations were quantitatively similar to those of the wild type. 5. Injection of EGTA to a final concentration of 10 mM into wild type cells neither modified the resting frequency nor blocked the frequency increase which normally accompanies hyperpolarization. 6. Transient ciliary reversal in both pawn and wild type produced by injection of Ca2+ could be terminated by the passage of inward current. The power stroke returned to the normal forward-swimming direction and the ciliary beating frequency increased. Upon termination of the inward current the cilia of Ca2+-injected cells again beat in reverse for many seconds. 7. The results support previous reports that increased frequency of beating and ciliary reversal seen in response to depolarization both require the entry of Ca2+ through the surface membrane. On the other hand, the results indicate that frequency increase with hyperpolarization is independent of an altered rate of Ca2+ entry. 8. Increased frequency during hyperpolarization appears to be related more closely to electrotonic membrane

  12. Simple suture and anchor in rabbit hips

    PubMed Central

    Garcia Filho, Fernando Cal; Guarniero, Roberto; de Godoy Júnior, Rui Maciel; Pereira, César Augusto Martins; Matos, Marcos Almeida; Garcia, Lucas Cortizo

    2012-01-01

    Objective Using biomechanical studies, this research aims to compare hip capsulorrhaphy in rabbits, carried out with two different techniques: capsulorrhaphy with simple sutures and with anchors. Method Thirteen New Zealand Albino (Oryctolaguscuniculus) male rabbits, twenty-six hip joints, were used. First, a pilot project was performed with three rabbits (six hip joints). This experiment consisted of ten rabbits divided into two groups: group 1 underwent capsulorrhaphy on both right and left hips with simple suture using polyglycolic acid absorbable thread, and group 2 underwent capsulorrhaphy with titanium anchors. After a four-week postoperative period, the animals were euthanized and the hip joints were frozen. On the same day of the biomechanical studies, after the hip joints were previously unfrozen, the following parameters were evaluated: rigidity, maximum force, maximum deformity and energy. Results There was no relevant statistical difference in rigidity, maximum force, maximum deformity and energy between the simple suture and anchor groups. Conclusion Through biomechanical analyses, using parameters of rigidity, maximum force, maximum deformity and energy, it has been shown that capsulorrhaphy with simple suture and with anchors has similar results in rabbit hip joints. Level of Evidence II, Prospective Comparative Study. PMID:24453618

  13. Hypercholesterolemia Impaired Sperm Functionality in Rabbits

    PubMed Central

    Monclus, Maria A.; Cabrillana, Maria E.; Clementi, Marisa A.; Espínola, Leandro S.; Cid Barría, Jose L.; Vincenti, Amanda E.; Santi, Analia G.; Fornés, Miguel W.

    2010-01-01

    Hypercholesterolemia represents a high risk factor for frequent diseases and it has also been associated with poor semen quality that may lead to male infertility. The aim of this study was to analyze semen and sperm function in diet-induced hypercholesterolemic rabbits. Twelve adult White New Zealand male rabbits were fed ad libitum a control diet or a diet supplemented with 0.05% cholesterol. Rabbits under cholesterol-enriched diet significantly increased total cholesterol level in the serum. Semen examination revealed a significant reduction in semen volume and sperm motility in hypercholesterolemic rabbits (HCR). Sperm cell morphology was seriously affected, displaying primarily a “folded head”-head fold along the major axe-, and the presence of cytoplasmic droplet on sperm flagellum. Cholesterol was particularly increased in acrosomal region when detected by filipin probe. The rise in cholesterol concentration in sperm cells was determined quantitatively by Gas chromatographic-mass spectrometric analyses. We also found a reduction of protein tyrosine phosphorylation in sperm incubated under capacitating conditions from HCR. Interestingly, the addition of Protein Kinase A pathway activators -dibutyryl-cyclic AMP and iso-butylmethylxanthine- to the medium restored sperm capacitation. Finally, it was also reported a significant decrease in the percentage of reacted sperm in the presence of progesterone. In conclusion, our data showed that diet-induced hypercholesterolemia adversely affects semen quality and sperm motility, capacitation and acrosomal reaction in rabbits; probably due to an increase in cellular cholesterol content that alters membrane related events. PMID:20976152

  14. Soda-anthraquinone pulping of palm oil empty fruit bunches and beating of the resulting pulp.

    PubMed

    Jiménez, L; Serrano, L; Rodríguez, A; Sánchez, R

    2009-02-01

    The influence of soda-anthraquinone pulping variables (temperature, time and soda concentration) and beating (number of PFI beating revolution) of palm oil empty fruit bunches (EFB) on the resulting paper sheets was studied, with a view to identifying the optimum operating conditions. Equations were derived that reproduced the properties of the paper sheets with errors less than 10-12% in 90-95% of cases. An optimum compromise was found as regards operating conditions (15% soda, 170 degrees C, 70 min and 2400 number of PFI beating revolutions) that provided paper properties departing by less than 12% from their optimum values (59.63 Nm/g tensile index, 4.48% stretch, 4.17 kN/g burst index and 7.20 m Nm(2)/g tear index), and a beating grade of 47.5 degrees SR, acceptable to obtain paper sheets. Because these conditions involve a lower soda, temperature, time and beating than those required to maximize the studied paper properties, they can save chemical reagents, energy and immobilized capital for industrial facilities. On the other hand, the stretch properties of these pulp beaten are higher than those of others non-wood pulps, as wheat straw and olive wood. PMID:18815028

  15. Independent Control of the Static and Dynamic Components of the Chlamydomonas Flagellar Beat.

    PubMed

    Geyer, Veikko F; Sartori, Pablo; Friedrich, Benjamin M; Jülicher, Frank; Howard, Jonathon

    2016-04-25

    When the green alga Chlamydomonas reinhardtii swims, it uses the breaststroke beat of its two flagella to pull itself forward [1]. The flagellar waveform can be decomposed into a static component, corresponding to an asymmetric time-averaged shape, and a dynamic component, corresponding to the time-varying wave [2]. Extreme lightening conditions photoshock the cell, converting the breaststroke beat into a symmetric sperm-like beat, which causes a reversal of the direction of swimming [3]. Waveform conversion is achieved by a reduction in magnitude of the static component, whereas the dynamic component remains unchanged [2]. The coupling between static and dynamic components, however, is poorly understood, and it is not known whether the static component requires the dynamic component or whether it can exist independently. We used isolated and reactivated axonemes [4] to investigate the relation between the two beat components. We discovered that, when reactivated in the presence of low ATP concentrations, axonemes displayed the static beat component in absence of the dynamic component. Furthermore, we found that the amplitudes of the two components depend on ATP in qualitatively different ways. These results show that the decomposition into static and dynamic components is not just a mathematical concept but that the two components can independently control different aspects of cell motility: the static component controls swimming direction, whereas the dynamic component provides propulsion. PMID:27040779

  16. Beat Synchronization across the Lifespan: Intersection of Development and Musical Experience

    PubMed Central

    Thompson, Elaine C.; White-Schwoch, Travis; Tierney, Adam; Kraus, Nina

    2015-01-01

    Rhythmic entrainment, or beat synchronization, provides an opportunity to understand how multiple systems operate together to integrate sensory-motor information. Also, synchronization is an essential component of musical performance that may be enhanced through musical training. Investigations of rhythmic entrainment have revealed a developmental trajectory across the lifespan, showing synchronization improves with age and musical experience. Here, we explore the development and maintenance of synchronization in childhood through older adulthood in a large cohort of participants (N = 145), and also ask how it may be altered by musical experience. We employed a uniform assessment of beat synchronization for all participants and compared performance developmentally and between individuals with and without musical experience. We show that the ability to consistently tap along to a beat improves with age into adulthood, yet in older adulthood tapping performance becomes more variable. Also, from childhood into young adulthood, individuals are able to tap increasingly close to the beat (i.e., asynchronies decline with age), however, this trend reverses from younger into older adulthood. There is a positive association between proportion of life spent playing music and tapping performance, which suggests a link between musical experience and auditory-motor integration. These results are broadly consistent with previous investigations into the development of beat synchronization across the lifespan, and thus complement existing studies and present new insights offered by a different, large cross-sectional sample. PMID:26107927

  17. Spin-dependent ringing and beats in a quantum dot system

    NASA Astrophysics Data System (ADS)

    Souza, Fabrício M.

    2007-11-01

    We report spin-dependent quantum coherent oscillations (ringing) and beats of the total and the spin currents flowing through a quantum dot with Zeeman split levels. The spin-dependent transport is calculated via nonequilibrium Green function in the transient after a bias voltage is turned on at t=0 . The dot is coupled to two electrodes that can be ferromagnetic or nonmagnetic. In the ferromagnetic case both parallel and antiparallel alignments are considered. The coherent oscillation and beat frequencies are controlled via the Zeeman energy EZ . In particular, for EZ=0 no beats are observed and the spin current is zero for nonmagnetic leads. In the ferromagnetic case a finite spin current is found for EZ=0 . The effects of temperature are also analyzed. We observe that with increasing temperature the ringing response and the beats tend to disappear. Additionally, the spin current goes to zero for nonmagnetic leads, remaining finite in the ferromagnetic case. The tunnel magnetoresistance also reveals quantum coherent oscillations and beats, and it attains negative values for small enough temperatures and short times.

  18. Beat Synchronization across the Lifespan: Intersection of Development and Musical Experience.

    PubMed

    Thompson, Elaine C; White-Schwoch, Travis; Tierney, Adam; Kraus, Nina

    2015-01-01

    Rhythmic entrainment, or beat synchronization, provides an opportunity to understand how multiple systems operate together to integrate sensory-motor information. Also, synchronization is an essential component of musical performance that may be enhanced through musical training. Investigations of rhythmic entrainment have revealed a developmental trajectory across the lifespan, showing synchronization improves with age and musical experience. Here, we explore the development and maintenance of synchronization in childhood through older adulthood in a large cohort of participants (N = 145), and also ask how it may be altered by musical experience. We employed a uniform assessment of beat synchronization for all participants and compared performance developmentally and between individuals with and without musical experience. We show that the ability to consistently tap along to a beat improves with age into adulthood, yet in older adulthood tapping performance becomes more variable. Also, from childhood into young adulthood, individuals are able to tap increasingly close to the beat (i.e., asynchronies decline with age), however, this trend reverses from younger into older adulthood. There is a positive association between proportion of life spent playing music and tapping performance, which suggests a link between musical experience and auditory-motor integration. These results are broadly consistent with previous investigations into the development of beat synchronization across the lifespan, and thus complement existing studies and present new insights offered by a different, large cross-sectional sample. PMID:26107927

  19. Global beta-beating compensation of the ALS W16 wiggler

    SciTech Connect

    Robin, D.; Decking, W.; Nishimura, H.

    1997-05-01

    The W16 wiggler is the first wiggler and highest field insertion device to be installed in the ALS storage ring. When the gaps of the W16 wiggler are closed, the vertical tune increases by 0.065 and the vertical beta function is distorted by up to {+-}37%. There are 48 quadrupoles in the ring whose fields can be adjusted individually to restore the tunes and partially compensate the beta-beating. In order to adjust the quadrupole field strengths to accurately compensate the focusing, it is necessary to have a method to precisely determine the beta-beating. In this paper we compare measurements of the induced beta-beating using two methods: measuring the tune dependence on quadrupole field strength and fitting a lattice model with measured response matrices. The fitted model also allows us to predict quadrupole field strengths that will best compensate the beta beating. These quadrupole field strengths are then applied and the resultant beta-beating is measured.

  20. Accumulation of sup 125 I-factor XI in atheroma of rabbit with hereditary hyperlipidemia (WHHL-rabbit)

    SciTech Connect

    Komiyama, Y.; Masuda, M.; Murakami, T.; Nishikado, H.; Egawa, H.; Nishimura, T.; Morii, S.; Murata, K. )

    1989-10-01

    We have studied the turnover and accumulation of rabbit factor XI (F.XI) in atherosclerotic lesion in Watanabe-hereditable hyperlipidemic rabbit (WHHL rabbit) to reveal the participation of blood coagulation in atherosclerotic lesion. Rabbit F.XI was iodinated and administered intravenously to WHHL rabbits and Japanese white rabbits. The turnover of {sup 125}I-rabbit F.XI was significantly faster in WHHL rabbits (T1/2 = 2.84 +/- 0.44 days) than in normal rabbits (T1/2 = 4.44 +/- 0.42 days). The thoracic aorta of WHHL rabbit was strongly labelled with {sup 125}I-rabbit F.XI, in sections obtained after 5 days by en-face autoradiography, whereas no radioactivity was detected in normal aorta. By an immunohistochemical study of WHHL rabbit aorta, we confirmed that many F.XI- and fibrin-related compounds existed in the atheroma, whereas albumin did not in these area. These results suggest that the activation of F.XI proceeds on the atherosclerotic lesions of WHHL rabbits.

  1. 9 CFR 354.124 - Quarantine of diseased rabbits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... shall be dealt with in one of the following ways: (a) If it is determined by a veterinary inspector that... veterinary inspector that further handling of the rabbits will not create a health hazard, such rabbits...

  2. 9 CFR 354.124 - Quarantine of diseased rabbits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... shall be dealt with in one of the following ways: (a) If it is determined by a veterinary inspector that... veterinary inspector that further handling of the rabbits will not create a health hazard, such rabbits...

  3. 9 CFR 354.124 - Quarantine of diseased rabbits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... shall be dealt with in one of the following ways: (a) If it is determined by a veterinary inspector that... veterinary inspector that further handling of the rabbits will not create a health hazard, such rabbits...

  4. White Rabbit in space related application

    NASA Astrophysics Data System (ADS)

    JamroŻy, M.; Gumiński, M.; Kasprowicz, G.; Romaniuk, R.; Poźniak, K.

    2015-09-01

    This paper describes study results regarding potential use of White Rabbit technology in Space Related Applications. During the study Technology Readiness Level and Compliance with Space Related Applications was evaluated. After considering possible deployment and development scenarios, main focus has been put on European Space Agency's tracking station system. This outcome derived from specific requirements of tracking system which are coherent with White Rabbit technology scope of application and further development plans. Current state of Time and Frequency Distribution technology implemented into tracking stations is based on multiple different technologies coexisting in parallel creating a complex system. It requires specific, custom made hardware to combine all the technologies which makes it expensive and difficult to maintain. White Rabbit could be use to reduce Time and Frequency Distribution to a single Ethernet based network with link redundancy, payload data transfer and sub-nanosecond accuracy.

  5. Dissociation of Calcium Transients and Force Development following a Change in Stimulation Frequency in Isolated Rabbit Myocardium

    PubMed Central

    Haizlip, Kaylan M.; Milani-Nejad, Nima; Varian, Kenneth D.; Slabaugh, Jessica L.; Walton, Shane D.; Gyorke, Sandor; Davis, Jonathan P.; Biesiadecki, Brandon J.; Janssen, Paul M. L.

    2015-01-01

    As the heart transitions from one exercise intensity to another, changes in cardiac output occur, which are modulated by alterations in force development and calcium handling. Although the steady-state force-calcium relationship at various heart rates is well investigated, regulation of these processes during transitions in heart rate is poorly understood. In isolated right ventricular muscle preparations from the rabbit, we investigated the beat-to-beat alterations in force and calcium during the transition from one stimulation frequency to another, using contractile assessments and confocal microscopy. We show that a change in steady-state conditions occurs in multiple phases: a rapid phase, which is characterized by a fast change in force production mirrored by a change in calcium transient amplitude, and a slow phase, which follows the rapid phase and occurs as the muscle proceeds to stabilize at the new frequency. This second/late phase is characterized by a quantitative dissociation between the calcium transient amplitude and developed force. Twitch timing kinetics, such as time to peak tension and 50% relaxation rate, reached steady-state well before force development and calcium transient amplitude. The dynamic relationship between force and calcium upon a switch in stimulation frequency unveils the dynamic involvement of myofilament-based properties in frequency-dependent activation. PMID:25961020

  6. Light stimulation of iris tyrosinase in vivo. [Rabbits

    SciTech Connect

    Dryja, T.P.; Kimball, G.P.; Albert, D.M.

    1980-05-01

    This paper presents evidence that light stimulates tyrosinase activity in iris melanocytes in rabbits. Levels of iris tyrosinase were found to be greater in eyes of rabbits exposed to light for 6 weeks than in eyes of rabbits maintained in darkness. Despite increasing tyrosinase levels, exposure to light produced no clinically observable change in iris color.

  7. General intravenous anesthesia for brachial plexus surgery in the rabbit.

    PubMed

    Reichert, P; Rutowski, R; Kielbowicz, Z; Kuryszko, J; Kielbowicz, M

    2013-01-01

    The rabbit is a good experimental model for brachial plexus surgery. The risks of death during anesthesia were significantly greater in rabbits than cats or dogs. This article presents the protocol of injectable anesthesia for a short surgical procedure, safe for the rabbit patient and convenient for the surgeon. PMID:24597314

  8. Comparative quantitative monitoring of rabbit haemorrhagic disease viruses in rabbit kittens

    PubMed Central

    2014-01-01

    Background Only one strain (the Czech CAPM-v351) of rabbit haemorrhagic disease virus (RHDV) has been released in Australia and New Zealand to control pest populations of the European rabbit O. cuniculus. Antigenic variants of RHDV known as RHDVa strains are reportedly replacing RHDV strains in other parts of the world, and Australia is currently investigating the usefulness of RHDVa to complement rabbit biocontrol efforts in Australia and New Zealand. RHDV efficiently kills adult rabbits but not rabbit kittens, which are more resistant to RHD the younger they are and which may carry the virus without signs of disease for prolonged periods. These different infection patterns in young rabbits may significantly influence RHDV epidemiology in the field and hence attempts to control rabbit numbers. Methods We quantified RHDV replication and shedding in 4–5 week old rabbits using quantitative real time PCR to assess their potential to shape RHDV epidemiology by shedding and transmitting virus. We further compared RHDV-v351 with an antigenic variant strain of RHDVa in kittens that is currently being considered as a potential RHDV strain for future release to improve rabbit biocontrol in Australia. Results Kittens were susceptible to infection with virus doses as low as 10 ID50. Virus growth, shedding and transmission after RHDVa infection was found to be comparable or non-significantly lower compared to RHDV. Virus replication and shedding was observed in all kittens infected, but was low in comparison to adult rabbits. Both viruses were shed and transmitted to bystander rabbits. While blood titres indicated that 4–5 week old kittens mostly clear the infection even in the absence of maternal antibodies, virus titres in liver, spleen and mesenteric lymph node were still high on day 5 post infection. Conclusions Rabbit kittens are susceptible to infection with very low doses of RHDV, and can transmit virus before they seroconvert. They may therefore play an important

  9. Spectral quantum beating in mixed frequency/time-domain coherent multidimensional spectroscopy.

    PubMed

    Pakoulev, Andrei V; Rickard, Mark A; Mathew, Nathan A; Kornau, Kathryn M; Wright, John C

    2007-08-01

    Coherent multidimensional spectroscopy performed in the mixed frequency/time domain exhibits both temporal and spectral quantum beating when two quantum states are simultaneously excited. The excitation of both quantum states can occur because either the spectral width of the states or the excitation pulse exceeds the frequency separation of the quantum states. The quantum beating appears as a line that broadens and splits into two peaks and then recombines as the time delay between excitation pulses increases. The splitting depends on the spectral width of the excitation pulses. We observe the spectral quantum beating between the two nearly degenerate asymmetric carbonyl stretch modes in a nickel tricarbonyl chelate using the nonrephasing, ground state bleaching coherence pathway in triply vibrationally enhanced four-wave mixing as the time delay between the first two excitation pulses changes. PMID:17628051

  10. Women's autonomy and support for wife beating: findings from a population-based survey in Jordan.

    PubMed

    Linos, Natalia; Khawaja, Marwan; Al-Nsour, Mohannad

    2010-01-01

    The aim of this study is to examine attitudes among married women toward wife beating and to investigate the hypothesis that female individual empowerment is associated with such attitudes within a broader context of societal patriarchy in Jordan. The study uses data from a cross-sectional survey of a representative sample of married women (n = 5,390) conducted in 2002. Associations between acceptance of wife beating and several women's empowerment variables, including decision-making power, as well as other risk factors were assessed, using odds ratios from binary logistic regression models. The key finding is that the vast majority (87.5%) of Jordanian women believe that wife beating is justified in at least one hypothetical scenario, and justification is negatively associated with empowerment variables and some demographic, geographic, and socioeconomic factors. PMID:20565010

  11. Substrate stiffness-modulated registry phase correlations in cardiomyocytes map structural order to coherent beating

    NASA Astrophysics Data System (ADS)

    Dasbiswas, K.; Majkut, S.; Discher, D. E.; Safran, Samuel A.

    2015-01-01

    Recent experiments show that both striation, an indication of the structural registry in muscle fibres, as well as the contractile strains produced by beating cardiac muscle cells can be optimized by substrate stiffness. Here we show theoretically how the substrate rigidity dependence of the registry data can be mapped onto that of the strain measurements. We express the elasticity-mediated structural registry as a phase-order parameter using a statistical physics approach that takes the noise and disorder inherent in biological systems into account. By assuming that structurally registered myofibrils also tend to beat in phase, we explain the observed dependence of both striation and strain measurements of cardiomyocytes on substrate stiffness in a unified manner. The agreement of our ideas with experiment suggests that the correlated beating of heart cells may be limited by the structural order of the myofibrils, which in turn is regulated by their elastic environment.

  12. Eliminating the Attentional Blink through Binaural Beats: A Case for Tailored Cognitive Enhancement

    PubMed Central

    Reedijk, Susan A.; Bolders, Anne; Colzato, Lorenza S.; Hommel, Bernhard

    2015-01-01

    Enhancing human cognitive performance is a topic that continues to spark scientific interest. Studies into cognitive-enhancement techniques often fail to take inter-individual differences into account, however, which leads to underestimation of the effectiveness of these techniques. The current study investigated the effect of binaural beats, a cognitive-enhancement technique, on attentional control in an attentional blink (AB) task. As predicted from a neurocognitive approach to cognitive control, high-frequency binaural beats eliminated the AB, but only in individuals with low spontaneous eye-blink rates (indicating low striatal dopamine levels). This suggests that the way in which cognitive-enhancement techniques, such as binaural beats, affect cognitive performance depends on inter-individual differences. PMID:26089802

  13. Substrate stiffness-modulated registry phase correlations in cardiomyocytes map structural order to coherent beating.

    PubMed

    Dasbiswas, K; Majkut, S; Discher, D E; Safran, Samuel A

    2015-01-01

    Recent experiments show that both striation, an indication of the structural registry in muscle fibres, as well as the contractile strains produced by beating cardiac muscle cells can be optimized by substrate stiffness. Here we show theoretically how the substrate rigidity dependence of the registry data can be mapped onto that of the strain measurements. We express the elasticity-mediated structural registry as a phase-order parameter using a statistical physics approach that takes the noise and disorder inherent in biological systems into account. By assuming that structurally registered myofibrils also tend to beat in phase, we explain the observed dependence of both striation and strain measurements of cardiomyocytes on substrate stiffness in a unified manner. The agreement of our ideas with experiment suggests that the correlated beating of heart cells may be limited by the structural order of the myofibrils, which in turn is regulated by their elastic environment. PMID:25597833

  14. On the Interaction of Two Beating Electrostatic Waves with Plasma Electrons

    NASA Astrophysics Data System (ADS)

    Malá, Z.

    2002-01-01

    This paper is devoted to the study of the interaction of particles with two beating plasma waves. We follow the instructional article by Ott and Dum. According to them, the sum of wave actions during the interaction is constant, supposing the effect of trapped particles on the beat can be neglected. In the present paper, this problem is solved more generally, just for the case of trapped and also untrapped particles in the wave. Our study shows that the sum of wave actions is constant also in the case when the influence of the trapped particles on the amplitudes of two waves was considered. On the contrary this conclusion is not valid if it is supposed that two original waves are amplitude modulated e.g. by the influence of the interaction of the beat with particles.

  15. Morphological and mechanical effects of extended beating on EFB pulp web

    NASA Astrophysics Data System (ADS)

    Zukeri, Mohd Ridzuan Hafiz Mohd; Ghazali, Arniza; Lazin, Mohd Azli Khairil Mat

    2012-09-01

    The pulp extracted from the alkaline peroxide pulping (APP) of EFB was beaten from 500 revolutions to 10000 revolutions using PFI mill to investigate the morphological changes undergone by the pulp and the resultant effect on paper sheet properties. As a result of beating, pulp elements were observed as intensely fibrillated, reducing the amounts of fibre bundles and thus, reducing interruption in the inter-fiber bonding. To a defined extent, beating was also seen as unwinding the structure of vessel element to a single strand of loose spiral body. These fibrillated vessel elements of APP pulp from EFB, plus the fines element germinating from further segmentation of the vessels, were the factors contributing to the overall strength improvement of the produced EFB pulp network. The applied increment in beating revolution had apparently widened the known broad spectrum quality of APP pulp from EFB. This demonstrates EFB potential for application in specialty paper production.

  16. Nitrosylation of rabbit ferrous heme-hemopexin.

    PubMed

    Fasano, Mauro; Bocedi, Alessio; Mattu, Marco; Coletta, Massimo; Ascenzi, Paolo

    2004-10-01

    Hemopexin (HPX) serves as a trap for toxic plasma heme, ensuring its complete clearance by transportation to the liver. Moreover, HPX-heme has been postulated to play a key role in the homeostasis of nitric oxide (NO). Here, the thermodynamics for NO binding to rabbit ferrous HPX-heme as well as the EPR and optical absorption spectroscopic properties of rabbit ferrous nitrosylated HPX-heme (HPX-heme-NO) are reported. The value of the dissociation equilibrium constant for NO binding to rabbit ferrous HPX-heme (i.e., H) is (1.4+/-0.2)x10(-7) M, at pH 7.0 and 10.0 degrees C; the value of H is unaffected by sodium chloride. At pH 7.0, rabbit ferrous HPX-heme-NO is a six-coordinate heme-iron species, characterized by an X-band EPR spectrum with an axial geometry and by epsilon=146 mM(-1) cm(-1) at 419 nm. At pH 4.0, rabbit ferrous HPX-heme-NO is a five-coordinate heme-iron species, characterized by an X-band EPR spectrum with three-line splitting centered at 334 mT and by epsilon=74 mM(-1) cm(-1) at 387 nm. The p K(a) value of the reversible pH-induced six- to five-coordinate spectroscopic transition is 4.8+/-0.1 in the absence of sodium chloride and 4.3+/-0.1 in the presence of 1.5x10(-1) M sodium chloride. This result is in agreement with the effect of sodium chloride on rabbit HPX-heme stability. The present data have been analyzed in parallel with those of a related heme model compound and heme-protein systems. PMID:15378409

  17. aBEAT: a toolbox for consistent analysis of longitudinal adult brain MRI.

    PubMed

    Dai, Yakang; Wang, Yaping; Wang, Li; Wu, Guorong; Shi, Feng; Shen, Dinggang

    2013-01-01

    Longitudinal brain image analysis is critical for revealing subtle but complex structural and functional changes of brain during aging or in neurodevelopmental disease. However, even with the rapid increase of clinical research and trials, a software toolbox dedicated for longitudinal image analysis is still lacking publicly. To cater for this increasing need, we have developed a dedicated 4D Adult Brain Extraction and Analysis Toolbox (aBEAT) to provide robust and accurate analysis of the longitudinal adult brain MR images. Specially, a group of image processing tools were integrated into aBEAT, including 4D brain extraction, 4D tissue segmentation, and 4D brain labeling. First, a 4D deformable-surface-based brain extraction algorithm, which can deform serial brain surfaces simultaneously under temporal smoothness constraint, was developed for consistent brain extraction. Second, a level-sets-based 4D tissue segmentation algorithm that incorporates local intensity distribution, spatial cortical-thickness constraint, and temporal cortical-thickness consistency was also included in aBEAT for consistent brain tissue segmentation. Third, a longitudinal groupwise image registration framework was further integrated into aBEAT for consistent ROI labeling by simultaneously warping a pre-labeled brain atlas to the longitudinal brain images. The performance of aBEAT has been extensively evaluated on a large number of longitudinal MR T1 images which include normal and dementia subjects, achieving very promising results. A Linux-based standalone package of aBEAT is now freely available at http://www.nitrc.org/projects/abeat. PMID:23577105

  18. Activating and relaxing music entrains the speed of beat synchronized walking.

    PubMed

    Leman, Marc; Moelants, Dirk; Varewyck, Matthias; Styns, Frederik; van Noorden, Leon; Martens, Jean-Pierre

    2013-01-01

    Inspired by a theory of embodied music cognition, we investigate whether music can entrain the speed of beat synchronized walking. If human walking is in synchrony with the beat and all musical stimuli have the same duration and the same tempo, then differences in walking speed can only be the result of music-induced differences in stride length, thus reflecting the vigor or physical strength of the movement. Participants walked in an open field in synchrony with the beat of 52 different musical stimuli all having a tempo of 130 beats per minute and a meter of 4 beats. The walking speed was measured as the walked distance during a time interval of 30 seconds. The results reveal that some music is 'activating' in the sense that it increases the speed, and some music is 'relaxing' in the sense that it decreases the speed, compared to the spontaneous walked speed in response to metronome stimuli. Participants are consistent in their observation of qualitative differences between the relaxing and activating musical stimuli. Using regression analysis, it was possible to set up a predictive model using only four sonic features that explain 60% of the variance. The sonic features capture variation in loudness and pitch patterns at periods of three, four and six beats, suggesting that expressive patterns in music are responsible for the effect. The mechanism may be attributed to an attentional shift, a subliminal audio-motor entrainment mechanism, or an arousal effect, but further study is needed to figure this out. Overall, the study supports the hypothesis that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement. The study opens up new perspectives for understanding the relationship between entrainment and expressiveness, with the possibility to develop applications that can be used in domains such as sports and physical rehabilitation. PMID:23874469

  19. Activating and Relaxing Music Entrains the Speed of Beat Synchronized Walking

    PubMed Central

    Leman, Marc; Moelants, Dirk; Varewyck, Matthias; Styns, Frederik; van Noorden, Leon; Martens, Jean-Pierre

    2013-01-01

    Inspired by a theory of embodied music cognition, we investigate whether music can entrain the speed of beat synchronized walking. If human walking is in synchrony with the beat and all musical stimuli have the same duration and the same tempo, then differences in walking speed can only be the result of music-induced differences in stride length, thus reflecting the vigor or physical strength of the movement. Participants walked in an open field in synchrony with the beat of 52 different musical stimuli all having a tempo of 130 beats per minute and a meter of 4 beats. The walking speed was measured as the walked distance during a time interval of 30 seconds. The results reveal that some music is ‘activating’ in the sense that it increases the speed, and some music is ‘relaxing’ in the sense that it decreases the speed, compared to the spontaneous walked speed in response to metronome stimuli. Participants are consistent in their observation of qualitative differences between the relaxing and activating musical stimuli. Using regression analysis, it was possible to set up a predictive model using only four sonic features that explain 60% of the variance. The sonic features capture variation in loudness and pitch patterns at periods of three, four and six beats, suggesting that expressive patterns in music are responsible for the effect. The mechanism may be attributed to an attentional shift, a subliminal audio-motor entrainment mechanism, or an arousal effect, but further study is needed to figure this out. Overall, the study supports the hypothesis that recurrent patterns of fluctuation affecting the binary meter strength of the music may entrain the vigor of the movement. The study opens up new perspectives for understanding the relationship between entrainment and expressiveness, with the possibility to develop applications that can be used in domains such as sports and physical rehabilitation. PMID:23874469

  20. Beating and insulting children as a risk for adult cancer, cardiac disease and asthma.

    PubMed

    Hyland, Michael E; Alkhalaf, Ahmed M; Whalley, Ben

    2013-12-01

    The use of physical punishment for children is associated with poor psychological and behavioral outcomes, but the causal pathway is controversial, and the effects on later physical health unknown. We conducted a cross-sectional survey of asthma, cancer, and cardiac patients (150 in each category, 75 male) recruited from outpatient clinics and 250 healthy controls (125 male). All participants were 40-60 years old and citizens of Saudi Arabia, where the use of beating and insults is an acceptable parenting style. Demographic data and recalled frequency of beatings and insults as a child were assessed on an 8-point scale. Beating and insults were highly correlated (ρ = 0.846). Propensity score matching was used to control for demographic differences between the disease and healthy groups. After controlling for differences, more frequent beating (once or more per month) and insults were associated with a significantly increased risk for cancer (RR = 1.7), cardiac disease (RR = 1.3) and asthma (RR = 1.6), with evidence of increased risk for cancer and asthma with beating frequency of once every 6 months or more. Our results show that a threatening parenting style of beating and insults is associated with increased risk for somatic disease, possibly because this form of parenting induces stress. Our findings are consistent with previous research showing that child abuse and other early life stressors adversely affect adult somatic health, but provide evidence that the pathogenic effects occur also with chronic minor stress. A stress-inducing parenting style, even when normative, has long term adverse health consequences. PMID:23054177

  1. Chromate reduction by rabbit liver aldehyde oxidase

    SciTech Connect

    Banks, R.B.; Cooke, R.T. Jr.

    1986-05-29

    Chromate was reduced during the oxidation of 1-methylnicotinamide chlorine by partially purified rabbit liver aldehyde oxidase. In addition to l-methylnicotinamide, several other electron donor substrates for aldehyde oxidase were able to support the enzymatic chromate reduction. The reduction required the presence of both enzyme and the electron donor substrate. The rate of the chromate reduction was retarded by inhibitors or aldehyde oxidase but was not affected by substrates or inhibitors of xanthine oxidase. These results are consistent with the involvement of aldehyde oxidase in the reduction of chromate by rabbit liver cytosolic enzyme preparations.

  2. Beat wave current drive experiment on the Davis Diverted Tokamak (DDT). Final report

    SciTech Connect

    Hwang, D.Q.; Horton, R.D.; Rogers, J.H. |

    1993-12-31

    The beatwave current drive experiment is summarized. The first phase of the experiment was the construction of the microwave sources and the diagnostics needed to demonstrate the beat wave effects, i.e. the measurement of the electrostatic plasma wave produced by the beating of two high intensity electromagnetic waves. In order to keep the cost of the experiments to a minimum, a low density filament plasma source (10{sup 8}) to (10{sup 10} particles cm{sup {minus}3}) was employed and the magnetic field in the toroidal plasma was produced by a dc power supply.

  3. Off-momentum beta-beat correction in the RHIC proton run

    SciTech Connect

    Luo Y.; Bai, M.; Fischer, W.; Marusic, A.; Mernick, K.; White, S.

    2012-05-20

    In this article, we will review the techniques to measure the off-momentum {beta}-beat and the correction algorithms with the chromatic arc sextupoles in RHIC. We will focus on the measurement and correction of the off-momentum {beta}*-beat at the interaction points. The off-momentum {beta}* is measured with the quadrupole strength change and a high resolution phase lock loop tune meter. The results of off-momentum {beta}* correction performed in a dedicated beam experiment in the 2012 RHIC 250 GeV polarized proton run are presented.

  4. Terahertz generation by beating two Langmuir waves in a warm and collisional plasma

    SciTech Connect

    Zhang, Xiao-Bo; Qiao, Xin; Cheng, Li-Hong; Tang, Rong-An; Zhang, Ai-Xia; Xue, Ju-Kui

    2015-09-15

    Terahertz (THz) radiation generated by beating of two Langmuir waves in a warm and collisional plasma is discussed theoretically. The critical angle between the two Langmuir waves and the critical wave-length (wave vector) of Langmuir waves for generating THz radiation are obtained analytically. Furthermore, the maximum radiation energy is obtained. We find that the critical angle, the critical wave-length, and the generated radiation energy strongly depend on plasma temperature and wave-length of the Langmuir waves. That is, the THz radiation generated by beating of two Langmuir waves in a warm and collisional plasma can be controlled by adjusting the plasma temperature and the Langmuir wave-length.

  5. Enhanced acceleration of injected electrons in a laser-beat-wave-induced plasma channel.

    PubMed

    Tochitsky, S Ya; Narang, R; Filip, C V; Musumeci, P; Clayton, C E; Yoder, R B; Marsh, K A; Rosenzweig, J B; Pellegrini, C; Joshi, C

    2004-03-01

    Enhanced energy gain of externally injected electrons by a approximately 3 cm long, high-gradient relativistic plasma wave (RPW) is demonstrated. Using a CO2 laser beat wave of duration longer than the ion motion time across the laser spot size, a laser self-guiding process is initiated in a plasma channel. Guiding compensates for ionization-induced defocusing (IID) creating a longer plasma, which extends the interaction length between electrons and the RPW. In contrast to a maximum energy gain of 10 MeV when IID is dominant, the electrons gain up to 38 MeV energy in a laser-beat-wave-induced plasma channel. PMID:15089478

  6. Effect of pulse slippage on beat wave THz generation in a rippled density magnetized plasma

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Rajouria, Satish Kumar; K, Magesh Kumar K.

    2013-10-01

    Beat wave excitation of terahertz radiation by nonlinear mixing of two laser pulses in a ripple density magnetized plasma is investigated allowing for the effect of pulse slippage. The lasers' ponderomotive-force-induced electron drift couples with the density ripple to produce a nonlinear current that resonantly drives the terahertz at the beat frequency. Density ripple provides the phase matching while the magnetic field, transverse to the direction of laser propagation, provides a transverse component to current density. However, the group velocity mismatch between the lasers and the terahertz radiation leads to slippage of the latter behind the laser pulses leading to saturation of the terahertz amplitude.

  7. The role of α-adrenergic receptors in mediating beat-by-beat sympathetic vascular transduction in the forearm of resting man

    PubMed Central

    Fairfax, Seth T; Holwerda, Seth W; Credeur, Daniel P; Zuidema, Mozow Y; Medley, John H; Dyke II, Peter C; Wray, D Walter; Davis, Michael J; Fadel, Paul J

    2013-01-01

    Sympathetic vascular transduction is commonly understood to act as a basic relay mechanism, but under basal conditions, competing dilatory signals may interact with and alter the ability of sympathetic activity to decrease vascular conductance. Thus, we determined the extent to which spontaneous bursts of muscle sympathetic nerve activity (MSNA) mediate decreases in forearm vascular conductance (FVC) and the contribution of local α-adrenergic receptor-mediated pathways to the observed FVC responses. In 19 young men, MSNA (microneurography), arterial blood pressure and brachial artery blood flow (duplex Doppler ultrasound) were continuously measured during supine rest. These measures were also recorded in seven men during intra-arterial infusions of normal saline, phentolamine (PHEN) and PHEN with angiotensin II (PHEN+ANG). The latter was used to control for increases in resting blood flow with α-adrenergic blockade. Spike-triggered averaging was used to characterize beat-by-beat changes in FVC for 15 cardiac cycles following each MSNA burst and a peak response was calculated. Following MSNA bursts, FVC initially increased by +3.3 ± 0.3% (P= 0.016) and then robustly decreased to a nadir of −5.8 ± 1.6% (P < 0.001). The magnitude of vasoconstriction appeared graded with the number of consecutive MSNA bursts; while individual burst size only had a mild influence. Neither PHEN nor PHEN+ANG infusions affected the initial rise in FVC, but both infusions significantly attenuated the subsequent decrease in FVC (–2.1 ± 0.7% and –0.7 ± 0.8%, respectively; P < 0.001 vs. normal saline). These findings indicate that spontaneous MSNA bursts evoke robust beat-by-beat decreases in FVC that are exclusively mediated via α-adrenergic receptors. PMID:23652594

  8. Cloning, Characteristics, and Functional Analysis of Rabbit NADPH Oxidase 5

    PubMed Central

    Chen, Feng; Yin, Caiyong; Dimitropoulou, Christiana; Fulton, David J. R.

    2016-01-01

    Background: Nox5 was the last member of the Nox enzyme family to be identified. Functionally distinct from the other Nox isoforms, our understanding of its physiological significance has been hampered by the absence of Nox5 in mouse and rat genomes. Nox5 is present in the genomes of other species such as the rabbit that have broad utility as models of cardiovascular disease. However, the mRNA sequence, characteristics, and functional analysis of rabbit Nox5 has not been fully defined and were the goals of the current study. Methods: Rabbit Nox5 was amplified from rabbit tissue, cloned, and sequenced. COS-7 cells were employed for expression and functional analysis via Western blotting and measurements of superoxide. We designed and synthesized miRNAs selectively targeting rabbit Nox5. The nucleotide and amino acid sequences of rabbit Nox5 were aligned with those of putative rabbit isoforms (X1, X2, X3, and X4). A phylogenetic tree was generated based on the mRNA sequence for Nox5 from rabbit and other species. Results: Sequence alignment revealed that the identified rabbit Nox5 was highly conserved with the predicted sequence of rabbit Nox5. Cell based experiments reveal that rabbit Nox5 was robustly expressed and produced superoxide at rest and in a calcium and PMA-dependent manner that was susceptible to superoxide dismutase and the flavoprotein inhibitor, DPI. miRNA-1 was shown to be most effective in down-regulating the expression of rabbit Nox5. Phylogenetic analysis revealed a close relationship between rabbit and armadillo Nox5. Rabbit Nox5 was relatively closely related to human Nox5, but lies in a distinct cluster. Conclusion: Our study establishes the suitability of the rabbit as a model organism to further our understanding of the role of Nox5 in cardiovascular and other diseases and provides new information on the genetic relationship of Nox5 genes in different species. PMID:27486403

  9. Possible interaction between myxomatosis and calicivirosis related to rabbit haemorrhagic disease affecting the European rabbit.

    PubMed

    Marchandeau, S; Bertagnoli, S; Peralta, B; Boucraut-Baralon, C; Letty, J; Reitz, F

    2004-11-01

    Serological data on myxoma virus, rabbit haemorrhagic disease (RHD) virus and RHD-like viruses in juvenile rabbits (Oryctolagus cuniculus) trapped in 1995, 1996 and 1997 in two areas of France were analysed. For each disease, the effects of bodyweight, year, month and seropositivity for the other disease were modelled by using logistic regressions. In one area, a model including RHD seropositivity was selected to explain the myxoma virus seropositivity. Models including myxoma virus seropositivity were selected to explain the RHD seropositivity in both areas, and the odds of a rabbit being seropositive to both viruses were 5.1 and 8.4 times higher than the odds of a rabbit being seronegative to myxoma virus and seropositive to RHD. The year and bodyweight had significant effects for myxomatosis in one area and for RHD in both areas. PMID:15573951

  10. Mnemonic Effect of Iconic Gesture and Beat Gesture in Adults and Children: Is Meaning in Gesture Important for Memory Recall?

    ERIC Educational Resources Information Center

    So, Wing Chee; Chen-Hui, Colin Sim; Wei-Shan, Julie Low

    2012-01-01

    Abundant research has shown that encoding meaningful gesture, such as an iconic gesture, enhances memory. This paper asked whether gesture needs to carry meaning to improve memory recall by comparing the mnemonic effect of meaningful (i.e., iconic gestures) and nonmeaningful gestures (i.e., beat gestures). Beat gestures involve simple motoric…

  11. Role of endothelin-1 receptors in healthy anaesthetized rabbits.

    PubMed

    Schmitz-Spanke, S; Schipke, J

    2001-08-01

    1. Many diseases are associated with elevated endothelin (ET)-1 plasma concentrations. In order to understand the consequence of this elevation, in the present study the effects of exogenous ET-1 on the entire organsim were investigated, in particular with respect to the role of ETA and ETB receptors in the cardiovascular system. In open-chest rabbits, left ventricular (LV) pressure (LVPmax, LVPed), dP/dtmax and dP/dtmin were recorded in ejecting and isovolumically beating hearts to determine cardiac function. In addition, heart rate (HR), aortic pressure (AoP) and aortic flow (AoF) were measured. Total peripheral resistance (TPR) was calculated from mean AoP and AoF. 2. In the first series of experiments (n = 11), ET-1 (0.5 nmol/kg; bolus) produced a non-significant reduction in HR. Systolic function, in terms of AoF, LVPmax and dP/dtmax, was improved; for example, LVPmax was increased significantly (69 +/- 10 vs 106 +/- 20 mmHg for control and ET-1, respectively; P < 0.05). Similarly, early relaxation (dP/dtmin) was improved. In parallel, TPR rose significantly (0.25+/-0.07 vs 0.35+/-0.1 mmHg/min per mL for control and ET-1, respectively; P < 0.05). Isovolumic measurements showed corresponding responses. 3. In the second series of experiments (n = 7), animals were pretreated with an ETA receptor antagonist (330 nmol/min per kg FR 139317). After ETA receptor blockade, the administration of ET-1 had no significant effect on cardiac function or vasomotion. 4. In the third series of experiments (n = 6), animals were pretreated with an ETB receptor antagonist (10 nmol/min per kg BQ 788). In this series of experiments, the effects of ET-1 on cardiac function and vasomotion were the same as in the first series of experiments, except for the effect on HR, which decreased by 35% after ET-1. 5. In our experimental model, exogenous ET-1 exerted a clear-cut positive inotropic effect, together with the anticipated peripheral vasoconstriction via ETA receptors. PMID:11473531

  12. An individual-based model of rabbit viral haemorrhagic disease on European wild rabbits (Oryctolagus cuniculus)

    USGS Publications Warehouse

    Fa, John E.; Sharples, Colin M.; Bell, Diana J.; DeAngelis, Donald L.

    2001-01-01

    We developed an individual-based model of Rabbit Viral Hemorrhagic Disease (RVHD) for European wild rabbits (Oryctolagus cuniculus L.), representing up to 1000 rabbits in four hectares. Model output for productivity and recruitment matched published values. The disease was density-dependent and virulence affected outcome. Strains that caused death after several days produced greater overall mortality than strains in which rabbits either died or recovered very quickly. Disease effect also depended on time of year. We also elaborated a larger scale model representing 25 km2 and 100,000+ rabbits, split into a number of grid-squares. This was a more traditional model that did not represent individual rabbits, but employed a system of dynamic equations for each grid-square. Disease spread depended on probability of transmission between neighboring grid-squares. Potential recovery from a major population crash caused by the disease relied on disease virulence and frequency of recurrence. The model's dependence on probability of disease transmission between grid-squares suggests the way that the model represents the spatial distribution of the population affects simulation. Although data on RVHD in Europe are lacking, our models provide a basis for describing the disease in realistic detail and for assessing influence of various social and spatial factors on spread.

  13. Urolithiasis and cystotomy in the rabbit.

    PubMed

    Brown, Cyndi

    2011-03-01

    Cystotomy is a surgical incision into the urinary bladder, which may be required for removal of calculi, diagnosis of tumors or refractory urinary tract infections, or repair of ectopic ureters and ruptured bladders. This column describes the indications and techniques for cystotomy in the rabbit. PMID:21326187

  14. CLONING AND EXPRESSION OF RABBIT INTERLEUKIN-15

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand the inflammatory mechanisms related to rabbit interleukin-15 (RIL-15), we cloned and expressed RIL-15 cDNA gene. A cDNA encoding RIL-15 was cloned from heart mRNA by reverse transcriptase polymerase chain reaction (RT-PCR) amplification using hIL-15 primers. The RIL-15 cDNA co...

  15. Childhood exposure to domestic violence and attitude towards wife beating in adult life: a study of men in India.

    PubMed

    Zhu, Ying; Dalal, Koustuv

    2010-03-01

    This study examined men's justification of wife beating in relation to their perceived rights and autonomy using a nationally representative sample of 18,047 men in India with childhood exposure to parental violence. Five reasons for wife beating justification, four items of men's perceived rights, and five items of household autonomy were analysed using chi2 test and logistic regression. Among 18,047 participants, 67% justified wife beating. Low education, economic stress and being unmarried were generally more associated with justifying wife beating for all five reasons. Wife's refusal of sex and husband's final say on household autonomy are risk factors. Joint autonomy on household decision making and wife's autonomy on managing her own earnings are protective factors. Perceived relationship rights and autonomy are highly predictive of wife-beating justification for the men who have been exposed to parental violence during childhood. The study has significant implications for public health planners and education strategies. PMID:19906319

  16. Measurement of GHz range magnetic field distribution near a coplanar waveguide using a beating field-type magnetic force microscope

    NASA Astrophysics Data System (ADS)

    Endo, Y.; Fukushima, M.; Arai, K.; Yanagi, K.; Shimada, Y.; Yamaguchi, M.

    2014-05-01

    This paper describes the measurement of microscopic radio frequency (RF) field distribution with a magnetic force microscope (MFM) tip exploring the beat signal from a coplanar waveguide (CPW) with a signal line as fine as 5 μm and a ground line of 50 μm. To produce a beating field in close proximity to the CPW, two RF currents with slightly different frequencies are supplied, where one is the signal current with a fixed frequency of 1.1 GHz and the other is the reference. The reference is adjusted to produce a beat with a frequency near the cantilever mechanical resonance frequency. Thus, the mechanical resonance of the cantilever excited by the beat field includes information about the 1.1 GHz field distribution from the CPW signal current. Detection of a beating field with a MFM tip can provide very high resolutions of the RF field distribution in the proximity of RF circuit component.

  17. Risk of zoonotic transmission of HEV from rabbits.

    PubMed

    Lhomme, Sébastien; Dubois, Martine; Abravanel, Florence; Top, Sokunthea; Bertagnoli, Stéphane; Guerin, Jean-Luc; Izopet, Jacques

    2013-10-01

    Hepatitis E virus strains from rabbits indicate that these mammals may be a reservoir for HEVs that cause infection in humans. Further issues remain to be clarified, including whether the genotype of rabbit HEV differs from human and swine HEV genotype 3 and whether rabbit HEV can infect human and other animals. HEV was found in farmed rabbits in several geographic areas of China, in USA and more recently in France. The prevalence of antibodies against HEV was 36%, 57% and 55% in rabbits from Virginia (USA), Gansu Province and Beijing (China), respectively. HEV RNA was detected in 16.5% of serum samples from farmed rabbits in Virginia, 7.5% in Gansu Province and 7.0% in Beijing. HEV RNA was detected in 7% of bile samples from farmed rabbits and in 23% of liver samples from wild rabbits in France. The full-length genomic sequences analysis indicates that all the rabbit strains belong to the same clade. Nucleotide sequences were 72.2-78.2% identical to HEV genotypes 1-4. Comparison with HEV sequences of human strains circulating in France and reference sequences identified a human strain closely related to rabbit HEV. A 93-nucleotide insertion in the X domain of the ORF1 of the human strain and in all the rabbit HEV strains was found. Moreover, the ability of rabbit HEV to cause cross-species infection in a pig model has recently been demonstrated. Rabbit HEV can replicate efficiently in human cell lines. Collectively, these data support the possibility of zoonotic transmission of HEV from rabbits. PMID:23474012

  18. Immune complex orchitis in vasectomized rabbits.

    PubMed

    Bigazzi, P E; Kosuda, L L; Hsu, K C; Andres, G A

    1976-02-01

    The results of the present study show that bilaterally vasectomized rabbits with high levels of antibodies to sperm antigens frequently develop an orchitis associated with granular deposits of rabbit IgG and C3 in the basement membranes of seminiferous tubules. The immune deposits correspond in location to electron-opaque deposits seen by electron microscopy. The "membranous orchitis" is characterized by thickening of tubular basement membranes, acc-mulation of macrophages and a few polymorphonuclear leukocytes, and destruction of the basal lamina, of the Sertoli and spermatogenetic cells. The pathogenetic role of the immune deposits and the possibility that they contain antigen-antibody complexes is indicated by: (a) selective accumulation of IgG and C3 granular deposits along the basement membranes of seminiferous tubules in rabbits producing high and persistent levels of antibodies to sperm antigens; (b) the elution of immunoglobulins from tissues with chaotropic ion-containing buffers, acid buffers, or heat; (c) the observation that the immuno-globulins accumulated in the testis contain antibody to sperm antigens; and (d) the demonstration of sperm antigens in a location similar to that of IgG and C3. It is postulated that sperm antigen-antibody complexes are formed in the basement membranes of seminiferous tubules when antigens leaking out of the tubules react with specific antibody coming from the circulation. In two rabbits with higher levels of circulating antisperm antibodies and severe orchitis, granular deposits of IgG and C3 were also present in renal glomeruli. Immunoglobulins eluted from the kidneys contained antibody with antisperm activity. These findings are consistent with the hypothesis that in some vasectomized rabbits extratesticular lesions may develop by a mechanism comparable to that of chronic serum sickness. PMID:129498

  19. EXPOSURE OF CULTURED MYOCYTES TO ZINC RESULTS IN ALTERED BEAT RATE AND INTERCELLULAR COMMUNICATION.

    EPA Science Inventory

    Exposure of cultured myocytes to zinc results in altered beat rate and intercellular communication

    Graff, Donald W, Devlin, Robert B, Brackhan, Joseph A, Muller-Borer, Barbara J, Bowman, Jill S, Cascio, Wayne E.

    Exposure to ambient air pollution particulate matter (...

  20. Swimming Speed of Larval Snail Does Not Correlate with Size and Ciliary Beat Frequency

    PubMed Central

    Chan, Kit Yu Karen; Jiang, Houshuo; Padilla, Dianna K.

    2013-01-01

    Many marine invertebrates have planktonic larvae with cilia used for both propulsion and capturing of food particles. Hence, changes in ciliary activity have implications for larval nutrition and ability to navigate the water column, which in turn affect survival and dispersal. Using high-speed high-resolution microvideography, we examined the relationship between swimming speed, velar arrangements, and ciliary beat frequency of freely swimming veliger larvae of the gastropod Crepidula fornicata over the course of larval development. Average swimming speed was greatest 6 days post hatching, suggesting a reduction in swimming speed towards settlement. At a given age, veliger larvae have highly variable speeds (0.8–4 body lengths s−1) that are independent of shell size. Contrary to the hypothesis that an increase in ciliary beat frequency increases work done, and therefore speed, there was no significant correlation between swimming speed and ciliary beat frequency. Instead, there are significant correlations between swimming speed and visible area of the velar lobe, and distance between centroids of velum and larval shell. These observations suggest an alternative hypothesis that, instead of modifying ciliary beat frequency, larval C. fornicata modify swimming through adjustment of velum extension or orientation. The ability to adjust velum position could influence particle capture efficiency and fluid disturbance and help promote survival in the plankton. PMID:24367554

  1. The Ability to Tap to a Beat Relates to Cognitive, Linguistic, and Perceptual Skills

    ERIC Educational Resources Information Center

    Tierney, Adam T.; Kraus, Nina

    2013-01-01

    Reading-impaired children have difficulty tapping to a beat. Here we tested whether this relationship between reading ability and synchronized tapping holds in typically-developing adolescents. We also hypothesized that tapping relates to two other abilities. First, since auditory-motor synchronization requires monitoring of the relationship…

  2. Influence of microwaves on the beating rate of isolated rat hearts

    SciTech Connect

    Yee, K.C.; Chou, C.K.; Guy, A.W.

    1988-01-01

    Previous reports have shown that microwave exposure can decrease the beating rate of isolated rat hearts. These experiments were conducted at room temperature and with the hearts exposed to air. We observed arrhythmia frequently at room temperature, and the variation of heart beat was so large that it makes the results difficult to reproduce. Therefore, we employed a double-circulating system to provide perfusion through the coronary artery and around the outside of the heart to maintain the rat hearts at 37.7 degrees C. No arrhythmias were observed in our experiments, and the hearts were beating for at least 1 h. The effects of 16-Hz modulated 2,450-MHz pulsed microwaves (10 microseconds, 100 pps) on the beating rate of 50 isolated rat hearts were studied. Results showed no statistically significant changes of heart rate in exposed groups at SARs of 2 and 10 W/kg compared with the control group. The effect seen at 200 W/kg was shown to be similar to that resulting from heating the heart.

  3. Utilization of negative beat-frequencies for maximizing the update-rate of OFDR

    NASA Astrophysics Data System (ADS)

    Gabai, Haniel; Botsev, Yakov; Hahami, Meir; Eyal, Avishay

    2015-07-01

    In traditional OFDR systems, the backscattered profile of a sensing fiber is inefficiently duplicated to the negative band of spectrum. In this work, we present a new OFDR design and algorithm that remove this redundancy and make use of negative beat frequencies. In contrary to conventional OFDR designs, it facilitates efficient use of the available system bandwidth and enables distributed sensing with the maximum allowable interrogation update-rate for a given fiber length. To enable the reconstruction of negative beat frequencies an I/Q type receiver is used. In this receiver, both the in-phase (I) and quadrature (Q) components of the backscatter field are detected. Following detection, both components are digitally combined to produce a complex backscatter signal. Accordingly, due to its asymmetric nature, the produced spectrum will not be corrupted by the appearance of negative beat-frequencies. Here, via a comprehensive computer simulation, we show that in contrast to conventional OFDR systems, I/Q OFDR can be operated at maximum interrogation update-rate for a given fiber length. In addition, we experimentally demonstrate, for the first time, the ability of I/Q OFDR to utilize negative beat-frequencies for long-range distributed sensing.

  4. Delaware Middle Schools Beating the Odds. Technical Report Number T2010.4

    ERIC Educational Resources Information Center

    Grusenmeyer, Linda; Fifield, Steve; Murphy, Aideen; Nian, Qinghua; Qian, Xiaoyu

    2010-01-01

    The investigation identified Delaware public and charter middle schools across the state which outperformed other Delaware middle schools with similar student demographic profiles. Teachers and administrators at six of these "Beating the Odds" schools and at six comparison middle schools were surveyed regarding their schools characteristics and…

  5. Attitudes toward Wife Beating: A Cross-Country Study in Asia

    ERIC Educational Resources Information Center

    Rani, Manju; Bonu, Sekhar

    2009-01-01

    Using demographic and health surveys conducted between 1998 and 2001 from seven countries (Armenia, Bangladesh, Cambodia, India, Kazakhstan, Nepal, and Turkey), the study found that acceptance of wife beating ranged from 29% in Nepal, to 57% in India (women only), and from 26% in Kazakhstan, to 56% in Turkey (men only). Increasing wealth predicted…

  6. Outcry against Violence: Beating Death of Student in Chicago Spurs Attention to a Nationwide Problem

    ERIC Educational Resources Information Center

    Aarons, Dakarai I.

    2009-01-01

    In the wake of the videotaped beating death of a Chicago high school student, law-enforcement officials and educators called this week for renewed efforts to stem youth violence. But they also acknowledged that money and programs alone will not solve the problem. Cabinet members traveled to Chicago to offer money and to call for adults to play a…

  7. Outcry against Violence: Beating Death of Student in Chicago Spurs Attention to a Nationwide Problem

    ERIC Educational Resources Information Center

    Aarons, Dakarai I.

    2010-01-01

    In the wake of the beating death of a Chicago high school student in September, law-enforcement officials and educators have called for renewed efforts to stem youth violence. But they also acknowledged that money and programs alone won't solve the problem. U.S. Attorney General Eric H. Holder and Secretary of Education Arne Duncan traveled to…

  8. Behind Beats and Rhymes: Working Class from a Hampton Roads Hip Hop Homeplace

    ERIC Educational Resources Information Center

    Durham, Aisha S.

    2009-01-01

    The film documentary titled "Hip Hop: beyond beats and rhymes" captures ongoing conversations among scholars, cultural critics, and hip hop insiders about the state of African Americans by interrogating distinct expressive forms associated with hip hop culture. Durham draws from two scenes to describe her memories as the researched underclass and…

  9. High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk

    PubMed Central

    Hommel, Bernhard; Sellaro, Roberta; Fischer, Rico; Borg, Saskia; Colzato, Lorenza S.

    2016-01-01

    Increasing evidence suggests that cognitive-control processes can be configured to optimize either persistence of information processing (by amplifying competition between decision-making alternatives and top-down biasing of this competition) or flexibility (by dampening competition and biasing). We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration. We hypothesized that binaural beats in the gamma range bias the cognitive-control style toward flexibility, which in turn should increase the crosstalk between tasks in a dual-task paradigm. We replicated earlier findings that the reaction time in the first-performed task is sensitive to the compatibility between the responses in the first and the second task—an indication of crosstalk. As predicted, exposing participants to binaural beats in the gamma range increased this effect as compared to a control condition in which participants were exposed to a continuous tone of 340 Hz. These findings provide converging evidence that the cognitive-control style can be systematically biased by inducing particular internal states; that high-frequency binaural beats bias the control style toward more flexibility; and that different styles are implemented by changing the strength of local competition and top-down bias. PMID:27605922

  10. High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk.

    PubMed

    Hommel, Bernhard; Sellaro, Roberta; Fischer, Rico; Borg, Saskia; Colzato, Lorenza S

    2016-01-01

    Increasing evidence suggests that cognitive-control processes can be configured to optimize either persistence of information processing (by amplifying competition between decision-making alternatives and top-down biasing of this competition) or flexibility (by dampening competition and biasing). We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration. We hypothesized that binaural beats in the gamma range bias the cognitive-control style toward flexibility, which in turn should increase the crosstalk between tasks in a dual-task paradigm. We replicated earlier findings that the reaction time in the first-performed task is sensitive to the compatibility between the responses in the first and the second task-an indication of crosstalk. As predicted, exposing participants to binaural beats in the gamma range increased this effect as compared to a control condition in which participants were exposed to a continuous tone of 340 Hz. These findings provide converging evidence that the cognitive-control style can be systematically biased by inducing particular internal states; that high-frequency binaural beats bias the control style toward more flexibility; and that different styles are implemented by changing the strength of local competition and top-down bias. PMID:27605922

  11. High Schools in California That Are Beating the Odds and How They Are Doing It

    ERIC Educational Resources Information Center

    Viloria, Jason

    2012-01-01

    The purpose of this phenomenological study was to determine the common programs and practices that Beating the Odds (BTO) high schools in California are using to achieve high graduation rates. More specifically, this study identifies specific programs and practices that the high schools are using to address at-risk student behaviors as well as…

  12. A novel scheme for graft allocation in non-heart beating donor renal transplantation.

    PubMed

    Laugharne, Matthew J; Clarke, Elaine; Younie, Mary E; Johnson, Rachel J; Rudge, Christopher J; Pentlow, Barry D; Morgan, Justin D; Dudley, Christopher R

    2008-06-15

    Patients waiting more than 3 years for a renal transplant were ranked according to our novel Bristol and Region Allocation by Non-heart beating Donor Score (BRANDS). One kidney from 40 non-heart beating donors was allocated to the highest BRANDS long-waiter and the other kidney allocated according to the UK National Allocation Scheme (NAS). The scheme reduced the number of patients waiting more than 3 years by 20%. Despite longer dialysis time, greater sensitization and more human leukocyte antigen mismatches, BRANDS patients had equivalent 3-year graft survival (BRANDS 91%, NAS 97%, P=0.264) and patient survival (BRANDS 94%, NAS 92%, P=0.99). Results were similar to 242 synchronous recipients from heart-beating donors. Renal function was significantly lower in BRANDS recipients (40 vs. 62 mL/min/1.73 m2, P<0.0001). Transplanting long-waiting patients with kidneys from non-heart beating donors has reduced waiting times without compromising early outcomes. It is unclear if equivalent survival will be sustained in the long term. PMID:18551076

  13. 76 FR 14737 - Bureau of Educational and Cultural Affairs (ECA) Request for Grant Proposals: One Beat

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-17

    ...-65 young (average age 19-35) foreign musicians and music professionals from selected countries that..., professional enrichment, and artistic production. By concentrating on music, One Beat seeks to combine these... international participants and with their American peers and American music professionals; Provide...

  14. The Effects of Visual Beats on Prosodic Prominence: Acoustic Analyses, Auditory Perception and Visual Perception

    ERIC Educational Resources Information Center

    Krahmer, Emiel; Swerts, Marc

    2007-01-01

    Speakers employ acoustic cues (pitch accents) to indicate that a word is important, but may also use visual cues (beat gestures, head nods, eyebrow movements) for this purpose. Even though these acoustic and visual cues are related, the exact nature of this relationship is far from well understood. We investigate whether producing a visual beat…

  15. Beat the Blues: A CBT Based Program for the Treatment of Depressive Symptomatology.

    ERIC Educational Resources Information Center

    Habicht, Manuela H.

    The present Beat the Blues Program is based in a cognitive-behavioral model. It has been developed as an 8-module group treatment program for 8-10 participants and is usually run over 8 weeks. Each module focuses on aspects of the model and provides exercises, strategies, and techniques for understanding and dealing with depression and anxiety.…

  16. Rhythm and Books: Feel the Beat! 1996 Florida Library Youth Program.

    ERIC Educational Resources Information Center

    Rupert, Libby, Comp.; And Others

    The Florida Library Youth Program is an extension of the Florida Summer Library Program and has emerged in response to a need to provide programs for school-age children at times other than the traditional summer vacation. The theme, "Rhythm and Books--Feel the Beat!," focuses on music and rhythms that abound around children in the world. The…

  17. Movement in Steady Beat: Learning on the Move, Ages 3-7. Second Edition.

    ERIC Educational Resources Information Center

    Weikart, Phyllis S.

    The ability to feel and maintain steady, rhythmic beat is important for children to develop in early childhood and will assist them in mastering concepts in language and literacy, mathematics, and other content areas as well as increase body coordination and related physical abilities. Designed as an activity supplement to High Scope movement and…

  18. Beat and metaphoric gestures are differentially associated with regional cerebellar and cortical volumes.

    PubMed

    Bernard, Jessica A; B Millman, Zachary; Mittal, Vijay A

    2015-10-01

    Gestures represent an integral aspect of interpersonal communication, and they are closely linked with language and thought. Brain regions for language processing overlap with those for gesture processing. Two types of gesticulation, beat gestures and metaphoric gestures are particularly important for understanding the taxonomy of co-speech gestures. Here, we investigated gesture production during taped interviews with respect to regional brain volume. First, we were interested in whether beat gesture production is associated with similar regions as metaphoric gesture. Second, we investigated whether cortical regions associated with metaphoric gesture processing are linked to gesture production based on correlations with brain volumes. We found that beat gestures are uniquely related to regional volume in cerebellar regions previously implicated in discrete motor timing. We suggest that these gestures may be an artifact of the timing processes of the cerebellum that are important for the timing of vocalizations. Second, our findings indicate that brain volumes in regions of the left hemisphere previously implicated in metaphoric gesture processing are positively correlated with metaphoric gesture production. Together, this novel work extends our understanding of left hemisphere regions associated with gesture to indicate their importance in gesture production, and also suggests that beat gestures may be especially unique. This provides important insight into the taxonomy of co-speech gestures, and also further insight into the general role of the cerebellum in language. PMID:26174599

  19. Electrical coupling of isolated cardiomyocyte clusters grown on aligned conductive nanofibrous meshes for their synchronized beating.

    PubMed

    Hsiao, Chun-Wen; Bai, Meng-Yi; Chang, Yen; Chung, Min-Fan; Lee, Ting-Yin; Wu, Cheng-Tse; Maiti, Barnali; Liao, Zi-Xian; Li, Ren-Ke; Sung, Hsing-Wen

    2013-01-01

    Myocardial infarction is often associated with abnormalities in electrical function due to a massive loss of functioning cardiomyocytes. This work develops a mesh, consisting of aligned composite nanofibers of polyaniline (PANI) and poly(lactic-co-glycolic acid) (PLGA), as an electrically active scaffold for coordinating the beatings of the cultured cardiomyocytes synchronously. Following doping by HCl, the electrospun fibers could be transformed into a conductive form carrying positive charges, which could then attract negatively charged adhesive proteins (i.e. fibronectin and laminin) and enhance cell adhesion. During incubation, the adhered cardiomyocytes became associated with each other and formed isolated cell clusters; the cells within each cluster elongated and aligned their morphology along the major axis of the fibrous mesh. After culture, expression of the gap-junction protein connexin 43 was clearly observed intercellularly in isolated clusters. All of the cardiomyocytes within each cluster beat synchronously, implying that the coupling between the cells was fully developed. Additionally, the beating rates among these isolated cell clusters could be synchronized via an electrical stimulation designed to imitate that generated in a native heart. Importantly, improving the impaired heart function depends on electrical coupling between the engrafted cells and the host myocardium to ensure their synchronized beating. PMID:23164424

  20. Beat-frequency adjustable Er3+-doped DBR fiber laser for ultrasound detection.

    PubMed

    Guo, Tuan; Wong, Allan C L; Liu, Wei-Sheng; Guan, Bai-Ou; Lu, Chao; Tam, Hwa-Yaw

    2011-01-31

    A compact low beat-frequency dual-polarization distributed Bragg reflector (DBR) fiber laser whose beat frequency can be varied, for high-frequency ultrasound detection has been proposed and experimentally demonstrated. The laser was fabricated in small birefringent commercial erbium-doped fiber. It operated in a robust single-longitude mode with output power of more than 1 mW and high signal-to-noise ratio better than 60 dB. Induced birefringence to the fiber during the UV inscription process is small (~10(-7)) and consequently the laser beats at a low frequency of ~20 MHz which is at least one order of magnitude smaller than previously reported results, making frequency down-conversion unnecessary. The beat frequency can be adjusted by controlling the side-exposure time of the UV light irradiating the gain cavity, providing a simple approach to multiplex a large number of DBR fiber lasers of different frequencies in series using frequency division multiplexing (FDM) technique. The proposed DBR fiber laser is also temperature insensitive, making it a good candidate for hydrophone applications. PMID:21369068

  1. Effects of Movement, Tempo, and Gender on Steady Beat Performance of Kindergarten Children

    ERIC Educational Resources Information Center

    Rose, Paige

    2016-01-01

    The purposes of this research were to discover the effects of manual (hand) and pedal (foot) movements, tempo, and gender on steady beat accuracy. Participants (N = 119) consisted of male (n = 63) and female (n = 56) kindergarten students randomly divided into two groups, counterbalanced with regard to school, homeroom, and gender. Participants…

  2. Beat Keeping in a Sea Lion As Coupled Oscillation: Implications for Comparative Understanding of Human Rhythm.

    PubMed

    Rouse, Andrew A; Cook, Peter F; Large, Edward W; Reichmuth, Colleen

    2016-01-01

    Human capacity for entraining movement to external rhythms-i.e., beat keeping-is ubiquitous, but its evolutionary history and neural underpinnings remain a mystery. Recent findings of entrainment to simple and complex rhythms in non-human animals pave the way for a novel comparative approach to assess the origins and mechanisms of rhythmic behavior. The most reliable non-human beat keeper to date is a California sea lion, Ronan, who was trained to match head movements to isochronous repeating stimuli and showed spontaneous generalization of this ability to novel tempos and to the complex rhythms of music. Does Ronan's performance rely on the same neural mechanisms as human rhythmic behavior? In the current study, we presented Ronan with simple rhythmic stimuli at novel tempos. On some trials, we introduced "perturbations," altering either tempo or phase in the middle of a presentation. Ronan quickly adjusted her behavior following all perturbations, recovering her consistent phase and tempo relationships to the stimulus within a few beats. Ronan's performance was consistent with predictions of mathematical models describing coupled oscillation: a model relying solely on phase coupling strongly matched her behavior, and the model was further improved with the addition of period coupling. These findings are the clearest evidence yet for parity in human and non-human beat keeping and support the view that the human ability to perceive and move in time to rhythm may be rooted in broadly conserved neural mechanisms. PMID:27375418

  3. Amplitude differences least squares method applied to temporal cardiac beat alignment

    NASA Astrophysics Data System (ADS)

    Correa, R. O.; Laciar, E.; Valentinuzzi, M. E.

    2007-11-01

    High resolution averaged ECG is an important diagnostic technique in post-infarcted and/or chagasic patients with high risk of ventricular tachycardia (VT). It calls for precise determination of the synchronism point (fiducial point) in each beat to be averaged. Cross-correlation (CC) between each detected beat and a reference beat is, by and large, the standard alignment procedure. However, the fiducial point determination is not precise in records contaminated with high levels of noise. Herein, we propose an alignment procedure based on the least squares calculation of the amplitude differences (LSAD) between the ECG samples and a reference or template beat. Both techniques, CC and LSAD, were tested in high resolution ECG's corrupted with white noise and 50 Hz line interference of varying amplitudes (RMS range: 0-100μV). Results point out that LSDA produced a lower alignment error in all contaminated records while in those blurred by power line interference better results were found only within the 0-40 μV range. It is concluded that the proposed method represents a valid alignment alternative.

  4. Beat Keeping in a Sea Lion As Coupled Oscillation: Implications for Comparative Understanding of Human Rhythm

    PubMed Central

    Rouse, Andrew A.; Cook, Peter F.; Large, Edward W.; Reichmuth, Colleen

    2016-01-01

    Human capacity for entraining movement to external rhythms—i.e., beat keeping—is ubiquitous, but its evolutionary history and neural underpinnings remain a mystery. Recent findings of entrainment to simple and complex rhythms in non-human animals pave the way for a novel comparative approach to assess the origins and mechanisms of rhythmic behavior. The most reliable non-human beat keeper to date is a California sea lion, Ronan, who was trained to match head movements to isochronous repeating stimuli and showed spontaneous generalization of this ability to novel tempos and to the complex rhythms of music. Does Ronan's performance rely on the same neural mechanisms as human rhythmic behavior? In the current study, we presented Ronan with simple rhythmic stimuli at novel tempos. On some trials, we introduced “perturbations,” altering either tempo or phase in the middle of a presentation. Ronan quickly adjusted her behavior following all perturbations, recovering her consistent phase and tempo relationships to the stimulus within a few beats. Ronan's performance was consistent with predictions of mathematical models describing coupled oscillation: a model relying solely on phase coupling strongly matched her behavior, and the model was further improved with the addition of period coupling. These findings are the clearest evidence yet for parity in human and non-human beat keeping and support the view that the human ability to perceive and move in time to rhythm may be rooted in broadly conserved neural mechanisms. PMID:27375418

  5. The Patterns of Music: Young Children Learning Mathematics through Beat, Rhythm, and Melody

    ERIC Educational Resources Information Center

    Geist, Kamile; Geist, Eugene A.; Kuznik, Kathleen

    2012-01-01

    Research on music and music therapy suggests that math and music are related in the brain from very early in life. Musical elements such as steady beat, rhythm, melody, and tempo possess inherent mathematical principles such as spatial properties, sequencing, counting, patterning, and one-to-one correspondence. With new understanding about the…

  6. Charge and current beats in T-shaped qubit-detector systems

    NASA Astrophysics Data System (ADS)

    Taranko, R.; Kwapiński, T.

    2015-06-01

    The time evolution of a charge qubit coupled electrostatically with different detectors in the forms of single, double and triple quantum dot linear systems in the T-shaped configuration between two reservoirs is theoretically considered. The correspondence between the qubit quantum dot oscillations and the detector current is studied for different values of the inter-dot tunneling amplitudes and the qubit-detector interaction strength. We have found that even for a qubit coupled with a single QD detector, the coherent beat patterns appear in the oscillations of the qubit charge. This effect is more evident for a qubit coupled with double or triple-QD detectors. The beats can be also observed in both the detector current and the detector quantum dot occupations. Moreover, in the presence of beats the qubit oscillations hold longer in time in comparison with the beats-free systems with monotonously decaying oscillations. The dependence of the qubit dynamics on different initial occupations of the detector sites (memory effect) is also analyzed.

  7. Crossbreeding effects on rabbit reproduction from four maternal lines of rabbits.

    PubMed

    Ragab, M; Sánchez, J P; Mínguez, C; Baselga, M

    2016-07-01

    Litter size is essential for an efficient production of rabbit meat. A diallel cross between four maternal lines was carried out and the analysis of the components of litter size has been already done. This paper presents the analysis of litter size traits themselves (total born (TB), number born alive (NBA), number weaned (NW)) and kindling interval (KI), that complete the analysis of the reproductive performance. The 16 genetic groups were distributed in four Spanish farms. The V line was present in all farms in order to be used as reference group. A total of 34 546 parities from 7111 does, were analysed. The crossbreeding parameters were estimated according to Dickerson model. The differences between lines performance were of low magnitude and not significant for litter size traits. The LP line showed the shortest KI followed by H respect to lines A and V. These differences reflected the differences between direct and maternal genetic effects. The differences between the average of all crosses and line V were found to be significant and seemed to be important, being 0.46 for TB, 0.56 for NBA, 0.75 for NW and -2.21 days for KI. The differences between reciprocal crosses for litter size were of low magnitude and non-significant, which indicate that the maternal effects are not important between these lines. In general, the lines did not show significant differences in direct and maternal genetic effects for TB, NBA and NW but there were some significant differences for KI, which ranged from 1.54 to 6.85 days in direct effects and from 0.63 to 3.38 days for maternal effects. A positive and, in some cases, relevant heterosis was found. The largest heterosis was for TB in the HV cross (1.05 rabbits), followed by the AH (0.74 rabbits), AV (0.57 rabbits) and LH (0.55 rabbits) crosses. For NBA, significant heterosis was found in HV (1.11 rabbits) and AV (0.49 rabbits) and for NW in AV (0.90 rabbits), LH (0.70 rabbits) and LV (0.58 rabbits). Favourable and significant

  8. Recombinant Rabbit Leukemia Inhibitory Factor and Rabbit Embryonic Fibroblasts Support the Derivation and Maintenance of Rabbit Embryonic Stem Cells

    PubMed Central

    Xue, Fei; Ma, Yinghong; Chen, Y. Eugene; Zhang, Jifeng; Lin, Tzu-An; Chen, Chien-Hong; Lin, Wei-Wen; Roach, Marsha; Ju, Jyh-Cherng; Yang, Lan; Du, Fuliang

    2012-01-01

    Abstract The rabbit is a classical experimental animal species. A major limitation in using rabbits for biomedical research is the lack of germ-line-competent rabbit embryonic stem cells (rbESCs). We hypothesized that the use of homologous feeder cells and recombinant rabbit leukemia inhibitory factor (rbLIF) might improve the chance in deriving germ-line-competent rbES cells. In the present study, we established rabbit embryonic fibroblast (REF) feeder layers and synthesized recombinant rbLIF. We derived a total of seven putative rbESC lines, of which two lines (M5 and M23) were from culture Condition I using mouse embryonic fibroblasts (MEFs) as feeders supplemented with human LIF (hLIF) (MEF+hLIF). Another five lines (R4, R9, R15, R21, and R31) were derived from Condition II using REFs as feeder cells supplemented with rbLIF (REF+rbLIF). Similar derivation efficiency was observed between these two conditions (8.7% vs. 10.2%). In a separate experiment with 2×3 factorial design, we examined the effects of feeder cells (MEF vs. REF) and LIFs (mLIF, hLIF vs. rbLIF) on rbESC culture. Both Conditions I and II supported satisfactory rbESC culture, with similar or better population doubling time and colony-forming efficiency than other combinations of feeder cells with LIFs. Rabbit ESCs derived and maintained on both conditions displayed typical ESC characteristics, including ESC pluripotency marker expression (AP, Oct4, Sox2, Nanog, and SSEA4) and gene expression (Oct4, Sox2, Nanog, c-Myc, Klf4, and Dppa5), and the capacity to differentiate into three primary germ layers in vitro. The present work is the first attempt to establish rbESC lines using homologous feeder cells and recombinant rbLIF, by which the rbESCs were derived and maintained normally. These cell lines are unique resources and may facilitate the derivation of germ-line-competent rbESCs. PMID:22775411

  9. Uncovering beat deafness: detecting rhythm disorders with synchronized finger tapping and perceptual timing tasks.

    PubMed

    Dalla Bella, Simone; Sowiński, Jakub

    2015-01-01

    A set of behavioral tasks for assessing perceptual and sensorimotor timing abilities in the general population (i.e., non-musicians) is presented here with the goal of uncovering rhythm disorders, such as beat deafness. Beat deafness is characterized by poor performance in perceiving durations in auditory rhythmic patterns or poor synchronization of movement with auditory rhythms (e.g., with musical beats). These tasks include the synchronization of finger tapping to the beat of simple and complex auditory stimuli and the detection of rhythmic irregularities (anisochrony detection task) embedded in the same stimuli. These tests, which are easy to administer, include an assessment of both perceptual and sensorimotor timing abilities under different conditions (e.g., beat rates and types of auditory material) and are based on the same auditory stimuli, ranging from a simple metronome to a complex musical excerpt. The analysis of synchronized tapping data is performed with circular statistics, which provide reliable measures of synchronization accuracy (e.g., the difference between the timing of the taps and the timing of the pacing stimuli) and consistency. Circular statistics on tapping data are particularly well-suited for detecting individual differences in the general population. Synchronized tapping and anisochrony detection are sensitive measures for identifying profiles of rhythm disorders and have been used with success to uncover cases of poor synchronization with spared perceptual timing. This systematic assessment of perceptual and sensorimotor timing can be extended to populations of patients with brain damage, neurodegenerative diseases (e.g., Parkinson's disease), and developmental disorders (e.g., Attention Deficit Hyperactivity Disorder). PMID:25867797

  10. Measuring Neural Entrainment to Beat and Meter in Infants: Effects of Music Background.

    PubMed

    Cirelli, Laura K; Spinelli, Christina; Nozaradan, Sylvie; Trainor, Laurel J

    2016-01-01

    Caregivers often engage in musical interactions with their infants. For example, parents across cultures sing lullabies and playsongs to their infants from birth. Behavioral studies indicate that infants not only extract beat information, but also group these beats into metrical hierarchies by as early as 6 months of age. However, it is not known how this is accomplished in the infant brain. An EEG frequency-tagging approach has been used successfully with adults to measure neural entrainment to auditory rhythms. The current study is the first to use this technique with infants in order to investigate how infants' brains encode rhythms. Furthermore, we examine how infant and parent music background is associated with individual differences in rhythm encoding. In Experiment 1, EEG was recorded while 7-month-old infants listened to an ambiguous rhythmic pattern that could be perceived to be in two different meters. In Experiment 2, EEG was recorded while 15-month-old infants listened to a rhythmic pattern with an unambiguous meter. In both age groups, information about music background (parent music training, infant music classes, hours of music listening) was collected. Both age groups showed clear EEG responses frequency-locked to the rhythms, at frequencies corresponding to both beat and meter. For the younger infants (Experiment 1), the amplitudes at duple meter frequencies were selectively enhanced for infants enrolled in music classes compared to those who had not engaged in such classes. For the older infants (Experiment 2), amplitudes at beat and meter frequencies were larger for infants with musically-trained compared to musically-untrained parents. These results suggest that the frequency-tagging method is sensitive to individual differences in beat and meter processing in infancy and could be used to track developmental changes. PMID:27252619

  11. Ciliary beating recovery in deficient human airway epithelial cells after lentivirus ex vivo gene therapy.

    PubMed

    Chhin, Brigitte; Negre, Didier; Merrot, Olivier; Pham, Jacqueline; Tourneur, Yves; Ressnikoff, Denis; Jaspers, Martine; Jorissen, Mark; Cosset, François-Loïc; Bouvagnet, Patrice

    2009-03-01

    Primary Ciliary Dyskinesia is a heterogeneous genetic disease that is characterized by cilia dysfunction of the epithelial cells lining the respiratory tracts, resulting in recurrent respiratory tract infections. Despite lifelong physiological therapy and antibiotics, the lungs of affected patients are progressively destroyed, leading to respiratory insufficiency. Recessive mutations in Dynein Axonemal Intermediate chain type 1 (DNAI1) gene have been described in 10% of cases of Primary Ciliary Dyskinesia. Our goal was to restore normal ciliary beating in DNAI1-deficient human airway epithelial cells. A lentiviral vector based on Simian Immunodeficiency Virus pseudotyped with Vesicular Stomatitis Virus Glycoprotein was used to transduce cultured human airway epithelial cells with a cDNA of DNAI1 driven by the Elongation Factor 1 promoter. Transcription and translation of the transduced gene were tested by RT-PCR and western blot, respectively. Human airway epithelial cells that were DNAI1-deficient due to compound heterozygous mutations, and consequently had immotile cilia and no outer dynein arm, were transduced by the lentivirus. Cilia beating was recorded and electron microscopy of the cilia was performed. Transcription and translation of the transduced DNAI1 gene were detected in human cells treated with the lentivirus. In addition, immotile cilia recovered a normal beat and outer dynein arms reappeared. We demonstrated that it is possible to obtain a normalization of ciliary beat frequency of deficient human airway epithelial cells by using a lentivirus to transduce cells with the therapeutic gene. This preliminary step constitutes a conceptual proof that is indispensable in the perspective of Primary Ciliary Dyskinesia's in vivo gene therapy. This is the first time that recovery of cilia beating is demonstrated in this disease. PMID:19300481

  12. Ciliary Beating Recovery in Deficient Human Airway Epithelial Cells after Lentivirus Ex Vivo Gene Therapy

    PubMed Central

    Chhin, Brigitte; Negre, Didier; Merrot, Olivier; Pham, Jacqueline; Tourneur, Yves; Ressnikoff, Denis; Jaspers, Martine; Jorissen, Mark; Cosset, François-Loïc; Bouvagnet, Patrice

    2009-01-01

    Primary Ciliary Dyskinesia is a heterogeneous genetic disease that is characterized by cilia dysfunction of the epithelial cells lining the respiratory tracts, resulting in recurrent respiratory tract infections. Despite lifelong physiological therapy and antibiotics, the lungs of affected patients are progressively destroyed, leading to respiratory insufficiency. Recessive mutations in Dynein Axonemal Intermediate chain type 1 (DNAI1) gene have been described in 10% of cases of Primary Ciliary Dyskinesia. Our goal was to restore normal ciliary beating in DNAI1–deficient human airway epithelial cells. A lentiviral vector based on Simian Immunodeficiency Virus pseudotyped with Vesicular Stomatitis Virus Glycoprotein was used to transduce cultured human airway epithelial cells with a cDNA of DNAI1 driven by the Elongation Factor 1 promoter. Transcription and translation of the transduced gene were tested by RT–PCR and western blot, respectively. Human airway epithelial cells that were DNAI1–deficient due to compound heterozygous mutations, and consequently had immotile cilia and no outer dynein arm, were transduced by the lentivirus. Cilia beating was recorded and electron microscopy of the cilia was performed. Transcription and translation of the transduced DNAI1 gene were detected in human cells treated with the lentivirus. In addition, immotile cilia recovered a normal beat and outer dynein arms reappeared. We demonstrated that it is possible to obtain a normalization of ciliary beat frequency of deficient human airway epithelial cells by using a lentivirus to transduce cells with the therapeutic gene. This preliminary step constitutes a conceptual proof that is indispensable in the perspective of Primary Ciliary Dyskinesia's in vivo gene therapy. This is the first time that recovery of cilia beating is demonstrated in this disease. PMID:19300481

  13. Measuring Neural Entrainment to Beat and Meter in Infants: Effects of Music Background

    PubMed Central

    Cirelli, Laura K.; Spinelli, Christina; Nozaradan, Sylvie; Trainor, Laurel J.

    2016-01-01

    Caregivers often engage in musical interactions with their infants. For example, parents across cultures sing lullabies and playsongs to their infants from birth. Behavioral studies indicate that infants not only extract beat information, but also group these beats into metrical hierarchies by as early as 6 months of age. However, it is not known how this is accomplished in the infant brain. An EEG frequency-tagging approach has been used successfully with adults to measure neural entrainment to auditory rhythms. The current study is the first to use this technique with infants in order to investigate how infants' brains encode rhythms. Furthermore, we examine how infant and parent music background is associated with individual differences in rhythm encoding. In Experiment 1, EEG was recorded while 7-month-old infants listened to an ambiguous rhythmic pattern that could be perceived to be in two different meters. In Experiment 2, EEG was recorded while 15-month-old infants listened to a rhythmic pattern with an unambiguous meter. In both age groups, information about music background (parent music training, infant music classes, hours of music listening) was collected. Both age groups showed clear EEG responses frequency-locked to the rhythms, at frequencies corresponding to both beat and meter. For the younger infants (Experiment 1), the amplitudes at duple meter frequencies were selectively enhanced for infants enrolled in music classes compared to those who had not engaged in such classes. For the older infants (Experiment 2), amplitudes at beat and meter frequencies were larger for infants with musically-trained compared to musically-untrained parents. These results suggest that the frequency-tagging method is sensitive to individual differences in beat and meter processing in infancy and could be used to track developmental changes. PMID:27252619

  14. Characterization of rabbit CD5 isoforms.

    PubMed

    Pospisil, Richard; Kabat, Juraj; Mage, Rose G

    2009-08-01

    Previously described polyclonal or monoclonal antibodies (mAb) to rabbit CD5, raised against expressed recombinant protein or peptides, recognize CD5 on most rabbit B cells. The mAb KEN-5 was originally reported to recognize rabbit CD5. However, KEN-5 binds almost exclusively to T cells and only to a minor population of B cells. We show here that by Enzyme-linked Immunosorbent Assay (ELISA), KEN-5 binds to recombinant rabbit CD5. This interaction is partially inhibited by polyclonal goat anti-CD5 antibody. In addition, immunoprecipitations from lysates of surface biotinylated rabbit lymphocytes with KEN-5 or our anti-CD5 mAb isolate molecules that migrate identically on gels with the same approximate relative molecular mass of 67,000 M(r). By flow cytometric analyses of individual cells from spleen, thymus and appendix, KEN-5 recognizes CD5-like molecules mainly on T cells and on 3-6% of IgM(+) B cells. Immunohistochemical staining of splenic and appendix tissues and confocal immunofluorescent imaging confirm and extend results from flow cytometric analyses. Quantitation of fluorescent colocalization indicates that staining by KEN-5 colocalizes with staining by anti-CD5 on small percentage lymphocytes in splenic tissue sections. As CD5 has both N- and O-linked glycosylation, we hypothesised that differential binding of KEN-5 to T cells and B-cells may be explained by different glycan structures on the CD5 present on T compared to B cells. This hypothesis is supported by ELISA data that show that deglycosylation diminishes the binding of KEN-5 to recombinant rabbit CD5. Screening KEN-5 on an array with 406 glycans was inconclusive. Although we did not identify a strongly binding glycan structure, the data are suggestive that the epitope recognized by KEN-5 may be influenced by glycan structures. The epitope this mAb recognizes may either be the glycan itself, or more likely, is influenced by neighboring glycan structure. Our findings suggest that development

  15. A filled duration illusion in music: Effects of metrical subdivision on the perception and production of beat tempo.

    PubMed Central

    Repp, Bruno H.; Bruttomesso, Meijin

    2010-01-01

    This study replicates and extends previous findings suggesting that metrical subdivision slows the perceived beat tempo (Repp, 2008). Here, musically trained participants produced the subdivisions themselves and were found to speed up, thus compensating for the perceived slowing. This was shown in a synchronization-continuation paradigm (Experiment 1) and in a reproduction task (Experiment 2a). Participants also judged the tempo of a subdivided sequence as being slower than that of a preceding simple beat sequence (Experiment 2b). Experiment 2 also included nonmusician participants, with similar results. Tempo measurements of famous pianists’ recordings of two variation movements from Beethoven sonatas revealed a strong tendency to play the first variation (subdivided beats) faster than the theme (mostly simple beats). A similar tendency was found in musicians’ laboratory performances of a simple theme and variations, despite instruc-tions to keep the tempo constant (Experiment 3a). When playing melodic sequences in which only one of three beats per measure was subdivided, musicians tended to play these beats faster and to perceive them as longer than adjacent beats, and they played the whole sequence faster than a sequence without any subdivisions (Experiments 3b and 3c). The results amply demonstrate a filled duration illusion in rhythm perception and music performance: Intervals containing events seem longer than empty intervals and thus must be shortened to be perceived as equal in duration. PMID:20689669

  16. The establishment of regular beating in populations of pacemaker heart cells. A study with tissue-cultured rat heart cells.

    PubMed

    Jongsma, H J; Tsjernina, L; de Bruijne, J

    1983-02-01

    Single isolated neonatal rat heart cells beat slowly (mean beating interval duration in the range of seconds) and irregularly (coefficient of variation greater than 40%). It is shown that slowness and irregularity of beating are intrinsic properties of the cells and are not caused by dissociation damage or lack of conditioning factors in the culture medium. When cell contacts are established either by letting the cultures grow for given amounts of time or by plating cells at increasing densities both interval duration and irregularity decrease. The beating regularity of small groups of interconnected cells (3 to 35 cells) and larger groups (200 to 15000 cells) is comparable. There is no clear cut proportionality between number of interconnected cells and beating regularity. Confluent monolayers beat fast (mean interval duration ranging between 200 and 400 ms and regular (coefficient of variation less than 5%). The hypothesis is discussed that this clock-like behavior of monolayers of heart cells is caused by the interaction of several pacemaker centers which are by themselves less regular and beat more slowly. PMID:6854658

  17. Fourier analysis of wing beat signals: assessing the effects of genetic alterations of flight muscle structure in Diptera.

    PubMed Central

    Hyatt, C J; Maughan, D W

    1994-01-01

    A method for determining and analyzing the wing beat frequency in Diptera is presented. This method uses an optical tachometer to measure Diptera wing movement during flight. The resulting signal from the optical measurement is analyzed using a Fast Fourier Transform (FFT) technique, and the dominant frequency peak in the Fourier spectrum is selected as the wing beat frequency. Also described is a method for determining quantitatively the degree of variability of the wing beat frequency about the dominant frequency. This method is based on determination of a quantity called the Hindex, which is derived using data from the FFT analysis. Calculation of the H index allows computer-based selection of the most suitable segment of recorded data for determination of the representative wing beat frequency. Experimental data suggest that the H index can also prove useful in examining wing beat frequency variability in Diptera whose flight muscle structure has been genetically altered. Examples from Drosophila indirect flight muscle studies as well as examples of artificial data are presented to illustrate the method. This method fulfills a need for a standardized method for determining wing beat frequencies and examining wing beat frequency variability in insects whose flight muscles have been altered by protein engineering methods. PMID:7811927

  18. Stretchable, multiplexed pH sensors with demonstrations on rabbit and human hearts undergoing ischemia.

    PubMed

    Chung, Hyun-Joong; Sulkin, Matthew S; Kim, Jong-Seon; Goudeseune, Camille; Chao, Hsin-Yun; Song, Joseph W; Yang, Sang Yoon; Hsu, Yung-Yu; Ghaffari, Roozbeh; Efimov, Igor R; Rogers, John A

    2014-01-01

    Stable pH is an established biomarker of health, relevant to all tissues of the body, including the heart. Clinical monitoring of pH in a practical manner, with high spatiotemporal resolution, is particularly difficult in organs such as the heart due to its soft mechanics, curvilinear geometry, heterogeneous surfaces, and continuous, complex rhythmic motion. The results presented here illustrate that advanced strategies in materials assembly and electrochemical growth can yield interconnected arrays of miniaturized IrOx pH sensors encapsulated in thin, low-modulus elastomers to yield conformal monitoring systems capable of noninvasive measurements on the surface of the beating heart. A thirty channel custom data acquisition system enables spatiotemporal pH mapping with a single potentiostat. In vitro testing reveals super-Nernstian sensitivity with excellent uniformity (69.9 ± 2.2 mV/pH), linear response to temperature (-1.6 mV °C(-1) ), and minimal influence of extracellular ions (<3.5 mV). Device examples include sensor arrays on balloon catheters and on skin-like stretchable membranes. Real-time measurement of pH on the surfaces of explanted rabbit hearts and a donated human heart during protocols of ischemia-reperfusion illustrate some of the capabilities. Envisioned applications range from devices for biological research, to surgical tools and long-term implants. PMID:23868871

  19. The detection of chronic cerebral hemorrhage in rabbits with magnetic induction

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Jin, Gui; Qin, Mingxin; Wan, Zibing; Wang, Jinbao; ChaoWang; Guo, Wanyou; Xu, Lin; Ning, Xu; Xu, Jia; Pu, Xianjie; Chen, Mingsheng; Zhao, Hongmei

    2012-12-01

    Chronic cerebral hemorrhage (CCH) in the brain is an important clinical problem that is often monitored and studied with expensive devices such as MRI and PET, which are not readily available in low economical resource parts of the world. We have developed a less expensive tool for non-contact monitoring of CCH in the brain. The system measures the phase shift between the electromagnetic signals on the two coils. CCH was induced in the brain of rabbits by stereotactic method. Intracranial pressure (ICP) and Electrocardiograph (ECG) of subjects were monitored for 1.5h. Signals were continuously monitored up to t=1.5h at exciting frequency 10.7MHz. From 0.8 to 2.4 ml of autologous blood was injected (each injection quantity of 0.8 ml, the interval time for 30 minutes). The results show significant phase shifts increase as a function of injection volume. ICP and phase shift were directly proportional to the related, while HRV were stable around 200beats*min-1. Our system has high sensitivity that even 0.8 ml can also be detected. In this study, the curves of inductive phase shift are significantly related to ICP. This observation suggests that the method could be valuable, in addition to continuous monitoring, also for early warning in emergency medicine and critical care units.

  20. Stochasticity intrinsic to coupled-clock mechanisms underlies beat-to-beat variability of spontaneous action potential firing in sinoatrial node pacemaker cells

    PubMed Central

    Yaniv, Yael; Lyashkov, Alexey E.; Sirenko, Syevda; Okamoto, Yosuke; Guiriba, Toni-Rose; Ziman, Bruce D.; Morrell, Christopher H.; Lakatta, Edward G.

    2014-01-01

    Recent evidence indicates that the spontaneous action potential (AP) of isolated sinoatrial node cells (SANC) is regulated by a system of stochastic mechanisms embodied within two clocks: ryanodine receptors of the “Ca2+ clock” within the sarcoplasmic reticulum, spontaneously activate during diastole and discharge local Ca2+ releases (LCRs) beneath the cell surface membrane; clock crosstalk occurs as LCRs activate an inward Na+/Ca2+ exchanger current (INCX), which together with If and decay of K+ channels prompts the “M clock,” the ensemble of sarcolemmal-electrogenic molecules, to generate APs. Prolongation of the average LCR period accompanies prolongation of the average AP beating interval (BI). Moreover, prolongation of the average AP BI accompanies increased AP BI variability. We hypothesized that both the average AP BI and AP BI variability are dependent upon stochasticity of clock mechanisms reported by the variability of LCR period. We perturbed the coupled-clock system by directly inhibiting the M clock by ivabradine (IVA) or the Ca2+ clock by cyclopiazonic acid (CPA). When either clock is perturbed by IVA (3, 10 and 30μM), which has no direct effect on Ca2+ cycling, or CPA ( 0.5 and 5μM), which has no direct effect on the M clock ion channels, the clock system failed to achieve the basal AP BI and both AP BI and AP BI variability increased. The changes in average LCR period and its variability in response to perturbations of the coupled-clock system were correlated with changes in AP beating interval and AP beating interval variability. We conclude that the stochasticity within the coupled-clock system affects and is affected by the AP BI firing rate and rhythm via modulation of the effectiveness of clock coupling. PMID:25257916

  1. Single Agent Antihypertensive Therapy and Orthostatic Blood Pressure Behaviour in Older Adults Using Beat-to-Beat Measurements: The Irish Longitudinal Study on Ageing

    PubMed Central

    Canney, Mark; O’Connell, Matthew D. L.; Murphy, Catriona M.; O’Leary, Neil; Little, Mark A.; O’Seaghdha, Conall M.; Kenny, Rose Anne

    2016-01-01

    Background Impaired blood pressure (BP) stabilisation after standing, defined using beat-to-beat measurements, has been shown to predict important health outcomes. We aimed to define the relationship between individual classes of antihypertensive agent and BP stabilisation among hypertensive older adults. Methods Cross-sectional analysis from The Irish Longitudinal Study on Ageing, a cohort study of Irish adults aged 50 years and over. Beat-to-beat BP was recorded in participants undergoing an active stand test. We defined grade 1 hypertension according to European Society of Cardiology criteria (systolic BP [SBP] 140-159mmHg ± diastolic BP [DBP] 90-99mmHg). Outcomes were: (i) initial orthostatic hypotension (IOH) (SBP drop ≥40mmHg ± DBP drop ≥20mmHg within 15 seconds [s] of standing accompanied by symptoms); (ii) sustained OH (SBP drop ≥20mmHg ± DBP drop ≥10mmHg from 60 to 110s inclusive); (iii) impaired BP stabilisation (SBP drop ≥20mmHg ± DBP drop ≥10mmHg at any 10s interval during the test). Outcomes were assessed using multivariable-adjusted logistic regression. Results A total of 536 hypertensive participants were receiving monotherapy with a renin-angiotensin-aldosterone-system inhibitor (n = 317, 59.1%), beta-blocker (n = 89, 16.6%), calcium channel blocker (n = 89, 16.6%) or diuretic (n = 41, 7.6%). A further 783 untreated participants met criteria for grade 1 hypertension. Beta-blockers were associated with increased odds of initial OH (OR 2.05, 95% CI 1.31–3.21) and sustained OH (OR 3.36, 95% CI 1.87–6.03) versus untreated grade 1 hypertension. Multivariable adjustment did not attenuate the results. Impaired BP stabilisation was evident at 20s (OR 2.59, 95% CI 1.58–4.25) and persisted at 110s (OR 2.90, 95% CI 1.64–5.11). No association was found between the other agents and any study outcome. Conclusion Beta-blocker monotherapy was associated with a >2-fold increased odds of initial OH and a >3-fold increased odds of sustained OH

  2. Novel, single-beat approach for determining both end-systolic pressure–dimension relationship and preload recruitable stroke work

    PubMed Central

    Inuzuka, Ryo; Kass, David A; Senzaki, Hideaki

    2016-01-01

    Objective The end-systolic pressure–dimension relationship (ESPDR) and the preload recruitable stroke work (PRSW) relationship are load-insensitive measures of contractility, but their clinical application has been limited by the need to record multiple beats over a wide volume range. In this study, we therefore sought to validate a new method to concomitantly determine the ESPDR and the PRSW relationship from a single beat. Methods Pressure–dimension loops were recorded in 14 conscious dogs under various haemodynamic and pathological conditions. Multiple-beat PRSW relationship was determined for its slope (Mw) and for a dimension-axis intercept (Dw). The ESPDR represented by the formula , was estimated from a steady-state, single-beat late-systolic pressure–dimension relationship. The single-beat Mw was determined as an end-systolic pressure when the end-systolic dimension was equal to Dw. Results A strong correlation was observed between multiple-beat and single-beat ESPDRs (zero-stress dimension; r=0.98, p<0.0001). The single-beat estimation of Mw calculated using the wall thickness was strongly correlated with the actual Mw (r=0.93, p<0.0001) and was sensitive enough to detect the change in contractility by dobutamine infusion (p<0.001) and by tachycardia-induced heart failure (p<0.001). Similar results were obtained for Mw estimated without information on wall thickness. Conclusions Mw can be interpreted as an end-systolic pressure when the end-systolic dimension is equal to Dw. By using the non-linear ESPDR, accurate single-beat estimation of the ESPDR and Mw is possible even without information on wall thickness. These results should enhance the applicability of pressure–volume framework to clinical medicine. PMID:27347424

  3. Gastric Perforation by Ingested Rabbit Bone Fragment

    PubMed Central

    Gambaracci, Giulio; Mecarini, Eleonora; Franceschini, Maria Silvia; Scialpi, Michele

    2016-01-01

    The majority of accidentally ingested foreign bodies is excreted from the gastrointestinal (GI) tract without any complications. Sometimes sharp foreign bodies – like chicken and fish bones – can lead to intestinal perforation and may present insidiously with a wide range of symptoms and, consequently, different diagnoses. We report the case of a 59-year-old woman presenting with fever and a 1-month history of vague abdominal pain. Computed tomography (CT) showed the presence of a hyperdense linear image close to the gastric antrum surrounded by a fluid collection and free peritoneal air. At laparotomy, a 4-cm rabbit bone fragment covered in inflamed tissue was detected next to a gastric wall perforation. Rabbit bone fragment ingestion, even if rarely reported, should not be underestimated as a possible cause of GI tract perforation. PMID:27403113

  4. Outbreak of rabbit hemorrhagic disease in domestic lagomorphs.

    PubMed

    Campagnolo, Enzo R; Ernst, Mark J; Berninger, Mary L; Gregg, Douglas A; Shumaker, Thomas J; Boghossian, Aida M

    2003-10-15

    Rabbit hemorrhagic disease (RHD) was diagnosed in domestic lagomorphs on a rabbit farm in Illinois. Clinical signs of RHD in affected rabbits included signs of depression, anorexia, fever, paddling, convulsions, and sudden death. Findings of necropsies and histologic evaluations of specimens of liver and spleen were indicative of RHD. In liver specimens obtained from dead rabbits, RHD viral antigen was detected via hemagglutination assay and viral antigen-detection ELISA. The source of the outbreak was traced to a rabbitry in Utah. As the disease spread, the outbreak involved rabbits in various regions of the United States; > 4,800 rabbits were euthanatized and buried as a result of the depopulation effort in several states. The economic impact of the disease can be considerable; if the disease is suspected, it is imperative that the appropriate state or federal veterinarian's office be contacted immediately. PMID:14584745

  5. Carbon tetrachloride-induced liver injury in the rabbit.

    PubMed Central

    Bernacchi, A. S.; de Castro, C. R.; de Ferreyra, E. C.; Villarruel, M. C.; Fernández, G.; de Fenos, O. M.; Castro, J. A.

    1983-01-01

    CCl4 administration to rabbits leads to early destruction of liver microsomal cytochrome P-450, to depression of glucose 6 phosphatase, to ultrastructurally revealable alterations and to an intense necrosis and fat accumulation in liver. Despite the known resistance of rabbit liver microsomes to lipid peroxidation, CCl4 administration to rabbits promoted lipid peroxidation of their liver microsomal lipids as revealable by the diene hyperconjugation technique, at periods of time from 1 to 12 h. Nevertheless, the intensity of this process is not equivalent to that occurring in rat liver microsomes, since the arachidonic acid content of rabbit liver microsomal lipids does not decrease at either 6 or 24 h after CCl4 administration. Rabbit liver is able to activate CCl4 to reactive metabolites that bind covalently to lipids. Relevance of covalent binding of CCl4 reactive metabolites and CCl4-promoted lipid peroxidation to CCl4-induced rabbit liver injury is analysed. Images Fig. 1 Fig. 2 PMID:6309207

  6. Influence of electromagnetic oscillating two-stream instability on the evolution of laser-driven plasma beat-wave

    SciTech Connect

    Gupta, D. N.; Singh, K. P.; Suk, H.

    2007-01-15

    The electrostatic oscillating two-stream instability of laser-driven plasma beat-wave was studied recently by Gupta et al. [Phys. Plasmas 11, 5250 (2004)], who applied their theory to limit the amplitude level of a plasma wave in the beat-wave accelerator. As a self-generated magnetic field is observed in laser-produced plasma, hence, the electromagnetic oscillating two-stream instability may be another possible mechanism for the saturation of laser-driven plasma beat-wave. The efficiency of this scheme is higher than the former.

  7. Alanine transport across in vitro rabbit vagina.

    PubMed

    Hajjar, J J; Mroueh, A M

    1979-04-01

    Transmural flux of alanine across the vaginal epithelium of the rabbit is a specialized mechanism. There is a net serosal to mucosal translocation of the amino acid in the absence of a concentration gradient. Changes in reproductive cycle do not influence this mechanism but, in castrated animals, it is abolished. Transport properties of vaginal epithelium is important because of increasing utilization of intravaginal contraceptives. PMID:455986

  8. Lactate metabolism in the fetal rabbit lung

    SciTech Connect

    Engle, M.J.; Brown, D.J.; Dooley, M.

    1986-05-01

    Lactate is frequently overlooked as a potential substrate for the fetal lung, even though it is present in the fetal circulation in concentrations as high as 8 mM. These high concentrations, coupled with the relatively low levels of glucose in the fetal blood, may indicate that lactate can substitute for glucose in pulmonary energy generation and phospholipid synthesis. A series of experiments was therefore undertaken in order to investigate the role of lactate in perinatal pulmonary development. Explants from 30 day gestation fetal rabbit lungs were incubated in Krebs-Ringer bicarbonate buffer supplemented with 3 mM (U-/sup 14/C)-glucose and varying levels of lactate. In the absence of medium lactate, fetal rabbit lung explants were capable of producing lactate at a rate of approximately 200 etamoles/mg protein/hour. The addition of lactate to the bathing medium immediately reduced net lactate production and above 4 mM, fetal rabbit lung explants became net utilizers of lactate. Media lactate concentrations of 2.5 mM, 5 mM and 10 mM also decreased glucose incorporation into total tissue disaturated phosphatidylcholine by approximately 20%, 35%, and 45%, respectively. Glucose incorporation into surfactant phosphatidylcholine was also reduced by approximately 50%, when lactate was present in the incubation medium at a concentration of 5 mM. Additional experiments also revealed that fetal lung lactate dehydrogenase activity was almost twice that found in the adult rabbit lung. These data indicate that lactate may be an important carbon source for the developing lung and could be a significant component in the manufacture of surfactant phosphatidylcholine during late gestation.

  9. Habitat Suitability Index Models: Swamp Rabbit

    USGS Publications Warehouse

    Allen, Arthur W.

    1985-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the swamp rabbit (Sylvilagus aquaticus). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) to 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  10. Liver lobe torsion in three adult rabbits.

    PubMed

    Wenger, S; Barrett, E L; Pearson, G R; Sayers, I; Blakey, C; Redrobe, S

    2009-06-01

    This paper describes three cases of liver lobe torsion in rabbits presenting with anorexia, lethargy, jaundice and abdominal pain. This condition was associated with anaemia and elevation of alanine aminotransferase, aspartate aminotransferase and gamma-glutamyl transferase. Abnormal radiological findings included hepatomegaly, gas-filled intestinal loops consistent with gastrointestinal ileus and ascites. Ultrasonographic findings included heterogeneous liver parenchyma, free abdominal fluid and reduced bowel motility. Diagnosis was confirmed by histopathological examination of the liver in all three cases. PMID:19527423

  11. Nonpathogenicity of antiintestinal antibody in the rabbit.

    PubMed Central

    Rabin, B. S.; Rogers, S. J.

    1976-01-01

    Rabbits were immunized with intestinal extract prepared from rabbits, guinea pigs, and germ-free rats. The resultant serum antibody response to intestinal antigen was determined by gel precipitation and direct tissue immunofluorescence. Forty-eight hours prior to sacrifice of each immunized animal, a portion of the duodenum, ileum, and colon were traumatized to bring circulating antibody into contact with the tissue. Sections for histology and direct immunofluorescence were taken from the area of trauma, just adjacent to the area, and 10 cm from it. The humoral immune response, the presence of tissue bound immunoglobulin, and tissue histology were compared. The area of trauma in normal and immunized animals showed the same histologic changes. In each animal, tissue just adjacent to the area of trauma and 10 cm from it were histologically identical. The pathologic alterations in the immunized animals were similar to those associated with malabsorption in man. Direct immunofluorescence of the intestinal tissue revealed bound immunoglobulin in histologically normal and abnormal tissue. Precipitating antibody to intestine was present in the serum of rabbits with normal and abnormal histology. Thus, antiintestinal antibody as dected by precipitation in gel and direct tissue immunofluorescence does not appear to be a factor in the pathogenesis of this model of immunologically induced histologic changes in the intestine. Images Figure 5 Figure 6 Figure 7 Figure 8 Figure 1 Figure 2 Figure 3 Figure 4 PMID:1266943

  12. Anterior cruciate ligament surgery in the rabbit

    PubMed Central

    2013-01-01

    Background Various methods regarding allograft knee replacements have been described. The animal models, which are generally used for this purpose include sheep, dogs, goats, and pigs, and accrue significant costs for study protocols. The authors herein describe an efficient and cost-effective model to study either native or tissue-engineered allografts for anterior cruciate ligament (ACL) replacement in a New Zealand rabbit model with the potential for transgenic and cell migration studies. Methods ACL reconstructions were performed in rabbits under general anesthesia. For fresh allograft implantations, two animals were operated in parallel. Each right extensor digitorum longus tendon was harvested and prepared for implantation. After excision of the ACL, tibial and femoral bone tunnels were created to implant each graft in the native ACL position. Results During a 2-year period, the authors have successfully undertaken this surgery in 61 rabbits and have not noticed any major complications attributed to this surgical technique. In addition, the authors have observed fast recovery in the animals postoperatively. Conclusion The authors recommend this surgical procedure as an excellent model for the study of knee surgery. PMID:23957941

  13. Sodium nitroprusside induces apoptosis of rabbit chondrocytes

    NASA Astrophysics Data System (ADS)

    Liang, Qian; Wang, Xiao-Ping; Chen, Tong-Sheng

    2013-02-01

    Osteoarthritis (OA) is characterized by a slowly progressing degradation of the matrix and destruction of articular cartilage. Apoptosis of chondrocyte is accounted for the mechanism of OA. Nitric oxide (NO), as a stimulus, has been shown to induce chondrocyte apoptosis by activating the matrix metalloproteinases (MMPs), increasing the expression of cyclooxygenase 2 (COX-2) and the level of prostaglandin E2 (PGE2), inhibiting the proteoglycan synthesis and type II collagen expression. In this study, sodium nitroprusside (SNP) was administered to be the NO donor to explore the mechanism of NO-induced apoptosis of rabbit chondrocytes obtained from six weeks old New Zealand rabbits. CCK-8 assay revealed the inhibitory effect of SNP on cell viability. We used flow cytometry (FCM) to assess the form of cell death by Annexin-V/propidium iodide (PI) double staining, and evaluate the change of mitochondrial membrane potential (ΔΨm). We found that the SNP induced chondrocyte apoptosis in a dose- and time-dependent manner and an observable reduction of ΔΨm. In conclusion, our findings indicate that SNP induces apoptosis of rabbit chondrocytes via a mitochondria-mediated pathway.

  14. Hypolipidaemic effects of Ballota undulata in rabbits.

    PubMed

    Qazan, Walid Sh

    2008-04-15

    The aim of to study the effect of Ballota undulata (70% EtOH) extract on lipid profile on Rabbits. The plant extract was orally administered to the atherogenic rabbits (atherogenic diet + cholesterol powder supplement 400 mg/kg/body weight/day dissolved in 5 mL coconut oil) at dose of 1.2 g kg(-1) body weight/day. During the overall period of the experiment blood was collected and serum was analyzed for lipid profile. Animals were sacrificed; the heart and the liver were collected and kept at -20 degrees C until assayed. Biochemical analysis of blood serum and tissue (liver and heart muscle) level were made for cholesterol, phospholipids and triglycerides. In addition blood serum was analyzed further for HDL-Cholesterol. All the results were statistically analyzed using students t-test. Hypolipidaemic nature of Ballota undulata (70% EtOH) extract was studied in hyperlipidaemic Rabbits. The increased cholesterol levels were brought to normal by administration of Ballota undulata. Serum cholesterol levels dropped from 940.7 to 230.41 (75.55%) and further to 119.2 (87.32%) by the end of the experiment. Similarly, phospholipids and triglycerides levels were observed to be also reduced. The tissues lipids profiles of liver and heart muscle showed similar changes in those noticed in serum lipids. Ballota undulata possesses active hypolipidaemic constituents. PMID:18819560

  15. BIORESORBABLE POLYMERIC MENISCAL PROSTHESIS: STUDY IN RABBITS

    PubMed Central

    Cardoso, Tulio Pereira; de Rezende Duek, Eliana Aparecida; Amatuzzi, Marco Martins; Caetano, Edie Benedito

    2015-01-01

    Objective: To induce growth of a neomeniscus into the pores of a prosthesis in order to protect the knee joint cartilage. Methods: 70 knees of 35 New Zealand rabbits were operated. The rabbits were five to seven months old, weighed 2 to 3.8 kilograms, and 22 were male and 13 were female. Each animal underwent medial meniscectomy in both knees during a single operation. A bioabsorbable polymeric meniscal prosthesis composed of 70% polydioxanone and 30% L-lactic acid polymer was implanted in one side. The animals were sacrificed after different postoperative time intervals. The femoral condyles and neomeniscus were subjected to histological analysis. Histograms were used to measure the degradation and absorption of the prosthesis, the growth of meniscal tissue in the prosthesis and the degree of degradation of the femoral condyle joint cartilage. Results: The data obtained showed that tissue growth histologically resembling a normal meniscus occurred, with gradual absorption of the prosthesis, and the percentages of chondrocytes on the control side and prosthesis side. Conclusion: Tissue growth into the prosthesis pores that histologically resembled the normal rabbit meniscus was observed. The joint cartilage of the femoral condyles on the prosthesis side presented greater numbers of chondrocytes in all its layers. PMID:27022549

  16. Milkweed control by food imprinted rabbits.

    PubMed

    Ducs, Anita; Kazi, Andrea; Bilkó, Ágnes; Altbäcker, Vilmos

    2016-09-01

    Many species of invasive plants are spreading out rapidly in Europe. The common milkweed occupies increasingly more area. Being poisonous, most animals will not graze on it however rabbits would be an effective organism for the biological control of milkweed. Rabbit kittens can learn the maternal diet in various ways. They prefer aromatic foods which their mother had eaten during pregnancy or lactation period, -even if it is poisonous- but they can also learn the maternal diet from the fecal pellets deposited by the mother into the nest during the nursing events. The present study was aimed to investigate if rabbit kittens can learn that the common milkweed is a potential food also. In the first 10days of their lives kits got fecal pellets originating from individuals having fed on common milkweed previously. When weaned on day 28 postpartum, these pups preferred the milkweed in the 3-way food choice test, opposite to the control group. Most surprisingly in a second experiment it was also shown that the common milkweed was also preferred by the kittens if their mother ate it not during, but one month before pregnancy. PMID:27451911

  17. Optical pacing of the adult rabbit heart.

    PubMed

    Jenkins, Michael W; Wang, Y T; Doughman, Y Q; Watanabe, M; Cheng, Y; Rollins, A M

    2013-01-01

    Optical pacing has been demonstrated to be a viable alternative to electrical pacing in embryonic hearts. In this study, the feasibility of optically pacing an adult rabbit heart was explored. Hearts from adult New Zealand White rabbits (n = 9) were excised, cannulated and perfused on a modified Langendorff apparatus. Pulsed laser light (λ = 1851 nm) was directed to either the left or right atrium through a multimode optical fiber. An ECG signal from the left ventricle and a trigger pulse from the laser were recorded simultaneously to determine when capture was achieved. Successful optical pacing was demonstrated by obtaining pacing capture, stopping, then recapturing as well as by varying the pacing frequency. Stimulation thresholds measured at various pulse durations suggested that longer pulses (8 ms) had a lower energy capture threshold. To determine whether optical pacing caused damage, two hearts were perfused with 30 µM of propidium iodide and analyzed histologically. A small number of cells near the stimulation site had compromised cell membranes, which probably limited the time duration over which pacing was maintained. Here, short-term optical pacing (few minutes duration) is demonstrated in the adult rabbit heart for the first time. Future studies will be directed to optimize optical pacing parameters to decrease stimulation thresholds and may enable longer-term pacing. PMID:24049683

  18. The normal microflora of the female rabbit's genital tract.

    PubMed Central

    Jacques, M; Olson, M E; Crichlow, A M; Osborne, A D; Costerton, J W

    1986-01-01

    Microorganisms associated with the vagina, cervix and uterus of rabbits were isolated and identified. The predominant microorganisms isolated from the vaginas and cervices were coagulase-negative staphylococci, micrococci, and nonfermentative bacilli. Coagulase-negative staphylococci were isolated frequently, but in small numbers, from the uteri. The pH of the rabbit vagina was found to be near neutrality. Our data indicate that the genital flora of female rabbits is relatively simple, regarding the number and type of microorganisms. PMID:3756680

  19. Transgenic rabbit that expresses a functional human lipoprotein (a)

    DOEpatents

    Rouy, Didier; Duverger, Nicolas; Emmanuel, Florence; Denefle, Patrice; Houdebine, Louis-Marie; Viglietta, Celine; Rubin, Edward M.; Hughes, Steven D.

    2003-01-01

    A transgenic rabbit which has in its genomic DNA sequences that encode apolipoprotein (a) and apolipoprotein B polypeptides which are capable of combining to produce lipoprotein (a), a process for creating such a rabbit, and the use of the rabbit to identify compounds which are effective in the treatment of human diseases which are associated with, induced and/or exacerbated by Lp(a) expression.

  20. Occurrence of Escherichia coli in Wild Cottontail Rabbits.

    PubMed

    Kozlowski, R; Glantz, P J; Anthony, R G

    1977-03-01

    Free-ranging cottontail rabbits (Sylvilagus floridanus) from two areas in central Pennsylvania were sampled over a 4-year period. Large numbers of coliforms were isolated from the intestinal tracts of these animals; in 136 of the 141 rabbits sampled, Escherichia coli was found to be a major component of the alimentary flora. Four serogroups (O7, O77, O73, and O103) were predominant among the isolates and were considered resistant coliflora of this species of cottontail rabbit. PMID:16345208