WorldWideScience

Sample records for activating delayed rectifier

  1. Antiarrhythmic properties of a rapid delayed-rectifier current activator in rabbit models of acquired long QT syndrome

    DEFF Research Database (Denmark)

    Diness, Thomas G; Yeh, Yung-Hsin; Qi, Xiao Yan;

    2008-01-01

    effect of a novel compound (NS1643) that activates the rapid delayed-rectifier K+ current, I(Kr), in two rabbit models of acquired LQTS. METHODS AND RESULTS: We used two clinically relevant in vivo rabbit models of TdP in which we infused NS1643 or vehicle: (i) three-week atrioventricular block...... with ventricular bradypacing; (ii) dofetilide-induced I(Kr) inhibition in methoxamine-sensitized rabbits. In addition, we studied effects on ionic currents in cardiomyocytes with I(Kr) suppressed by bradycardia remodelling or dofetilide exposure. Bradypaced rabbits developed QT interval prolongation, spontaneous...... ventricular ectopy, and TdP. Infusion of NS1643 completely suppressed arrhythmic activity and shortened the QT interval; vehicle had no effect. NS1643 also suppressed ventricular tachyarrhythmias caused by infusion of dofetilide to methoxamine-sensitized rabbits, and reversed dofetilide-induced QT...

  2. A Carbohydrate Fraction, AIP1, from Artemisia Iwayomogi Reduces the Action Potential Duration by Activation of Rapidly Activating Delayed Rectifier K+ Channels in Rabbit Ventricular Myocytes

    OpenAIRE

    Park, Won Sun; Son, Youn Kyoung; Ko, Eun A.; Choi, Seong Woo; Kim, Nari; Choi, Tae-Hoon; Youn, Hyun Joo; Jo, Su-Hyun; Hong, Da Hye; Han, Jin

    2010-01-01

    We investigated the effects of a hot-water extract of Artemisia iwayomogi, a plant belonging to family Compositae, on cardiac ventricular delayed rectifier K+ current (IK) using the patch clamp technique. The carbohydrate fraction AIP1 dose-dependently increased the heart rate with an apparent EC50 value of 56.1±5.5 µg/ml. Application of AIP1 reduced the action potential duration (APD) in concentration-dependent fashion by activating IK without significantly altering the resting membrane pote...

  3. Characterization of the rapidly activating delayed rectifier potassium current, I (Kr), in HL-1 mouse atrial myocytes.

    Science.gov (United States)

    Toyoda, Futoshi; Ding, Wei-Guang; Zankov, Dimitar P; Omatsu-Kanbe, Mariko; Isono, Takahiro; Horie, Minoru; Matsuura, Hiroshi

    2010-06-01

    HL-1 is the adult murine cardiac cell line that can be passaged repeatedly in vitro without losing differentiated phenotype. The present study was designed to characterize the rapidly activating delayed rectifier potassium current, I (Kr), endogenously expressed in HL-1 cells using the whole-cell patch-clamp technique. In the presence of nisoldipine, depolarizing voltage steps applied from a holding potential of -50 mV evoked the time-dependent outward current, followed by slowly decaying outward tail current upon return to the holding potential. The amplitude of the current increased with depolarizations up to 0 mV but then progressively decreased with further depolarizations. The time-dependent outward current as well as the tail current were highly sensitive to block by E-4031 and dofetilide (IC(50) of 21.1 and 15.1 nM, respectively) and almost totally abolished by micromolar concentrations of each drug, suggesting that most of the outward current in HL-1 cells was attributable to I (Kr). The magnitude of I (Kr) available from HL-1 cells (18.1 +/- 1.5 pA pF(-1)) was sufficient for reliable measurements of various gating parameters. RT-PCR and Western blot analysis revealed the expression of alternatively spliced forms of mouse ether-a-go-go-related genes (mERG1), the full-length mERG1a and the N-terminally truncated mERG1b isoforms. Knockdown of mERG1 transcripts with small interfering RNA (siRNA) dramatically reduced I (Kr) amplitude, confirming the molecular link of mERG1 and I (Kr) in HL-1 cells. These findings demonstrate that HL-1 cells possess I (Kr) with properties comparable to those in native cardiac I (Kr) and provide an experimental model suitable for studies of I (Kr) channels.

  4. Pharmacological activation of rapid delayed rectifier potassium current suppresses bradycardia-induced triggered activity in the isolated guinea pig heart

    DEFF Research Database (Denmark)

    Hansen, Rie Schultz; Olesen, Søren-Peter; Grunnet, Morten

    2007-01-01

    arrhythmias. We present here data that support that NS3623 affects native I(Kr) and report the effects that activating this potassium current have in the intact guinea pig heart. In Langendorff-perfused hearts, the compound showed a concentration-dependent shortening of action potential duration, which...

  5. Photoperiod Modulates Fast Delayed Rectifier Potassium Currents in the Mammalian Circadian Clock

    Directory of Open Access Journals (Sweden)

    Sahar Farajnia

    2016-09-01

    Full Text Available One feature of the mammalian circadian clock, situated in the suprachiasmatic nucleus (SCN, is its ability to measure day length and thereby contribute to the seasonal adaptation of physiology and behavior. The timing signal from the SCN, namely the 24 hr pattern of electrical activity, is adjusted according to the photoperiod being broader in long days and narrower in short days. Vasoactive intestinal peptide and gamma-aminobutyric acid play a crucial role in intercellular communication within the SCN and contribute to the seasonal changes in phase distribution. However, little is known about the underlying ionic mechanisms of synchronization. The present study was aimed to identify cellular mechanisms involved in seasonal encoding by the SCN. Mice were adapted to long-day (light–dark 16:8 and short-day (light–dark 8:16 photoperiods and membrane properties as well as K+ currents activity of SCN neurons were measured using patch-clamp recordings in acute slices. Remarkably, we found evidence for a photoperiodic effect on the fast delayed rectifier K+ current, that is, the circadian modulation of this ion channel’s activation reversed in long days resulting in 50% higher peak values during the night compared with the unaltered day values. Consistent with fast delayed rectifier enhancement, duration of action potentials during the night was shortened and afterhyperpolarization potentials increased in amplitude and duration. The slow delayed rectifier, transient K+ currents, and membrane excitability were not affected by photoperiod. We conclude that photoperiod can change intrinsic ion channel properties of the SCN neurons, which may influence cellular communication and contribute to photoperiodic phase adjustment.

  6. Rapid component I(Kr) of cardiac delayed rectifier potassium currents in guinea-pig is inhibited by alpha(1)-adrenoreceptor activation via protein kinase A and protein kinase C-dependent pathways.

    Science.gov (United States)

    Wang, Sen; Xu, Dong-Jie; Cai, Jing-Bo; Huang, Yuan-Zhu; Zou, Jian-Gang; Cao, Ke-Jiang

    2009-04-17

    Ventricular tachyarrhythmias are often precipitated by physical or emotional stress, indicating a link between increased adrenergic stimulation and cardiac ion channel activity. Human ether-a-go-go related gene (hERG) potassium channels conduct the rapid component of delayed rectifier potassium current, I(kr), a crucial component for action potential repolarization. To evaluate the correlation between increased alpha(1)-adrenergic activity and the rapid component of cardiac I(kr), whole-cell patch-clamp recording was performed in isolated guinea-pig ventricular myocytes. Stimulation of alpha(1)-adrenoceptors using phenylephrine (0.1 nM-100 microM) reduced I(kr) current in a dose-dependent manner at 37 degrees C. Phenylephrine (0.1 microM) reduced I(kr) current to 66.83+/-3.16%. Chelerythrine (1 microM), a specific inhibitor of protein kinase C (PKC) completely inhibited the changes in I(kr) trigged by 0.1 microM phenylephrine. KT5720 (2.5 microM), a specific inhibitor of protein kinase A (PKA) partially inhibited the current decrease induced by 0.1 microM phenylephrine. Both chelerythrine and KT5720 drastically reduced the phenylephrine-induced effects, indicating possible involvement of PKC and PKA in the alpha(1)-adrenergic inhibition of I(kr). Our data suggest a link between I(kr) and the alpha(1)-adrenoceptor, involving activation of PKC and PKA in arrhythmogenesis.

  7. Cloning and expression of a rat cardiac delayed rectifier potassium channel.

    OpenAIRE

    Paulmichl, M.; Nasmith, P; Hellmiss, R; Reed, K.; Boyle, W A; Nerbonne, J M; Peralta, E G; Clapham, D.E.

    1991-01-01

    We have cloned a cDNA (designated RAK) coding for a delayed-rectifier K current (IRAK) from adult rat heart atrium and expressed it in Xenopus oocytes. RAK differs from the cloned rat brain K current, BK2 [McKinnon, D. (1989) J. Biol. Chem. 264, 8230-8236], by one amino acid at residue 411. RAK expressed in oocytes compares closely to the intrinsic adult rat atrial delayed-rectifier current measured by using whole-cell recording of single isolated cells. Northern blot analysis confirmed the p...

  8. Deletion of the Kv2.1 delayed rectifier potassium channel leads to neuronal and behavioral hyperexcitability

    OpenAIRE

    Speca, DJ; Ogata, G; Mandikian, D; Bishop, HI; Wiler, SW; Eum, K; Wenzel, HJ; Doisy, ET; Matt, L; Campi, KL; Golub, MS; Nerbonne, JM; Hell, JW; Trainor, BC; Sack, JT

    2014-01-01

    The Kv2.1 delayed rectifier potassium channel exhibits high-level expression in both principal and inhibitory neurons throughout the central nervous system, including prominent expression in hippocampal neurons. Studies of in vitro preparations suggest that Kv2.1 is a key yet conditional regulator of intrinsic neuronal excitability, mediated by changes in Kv2.1 expression, localization and function via activity-dependent regulation of Kv2.1 phosphorylation. Here we identify neurological and b...

  9. Subcellular localization of the delayed rectifier K(+) channels KCNQ1 and ERG1 in the rat heart

    DEFF Research Database (Denmark)

    Rasmussen, Hanne Borger; Møller, Morten; Knaus, Hans-Günther

    2003-01-01

    In the heart, several K(+) channels are responsible for the repolarization of the cardiac action potential, including transient outward and delayed rectifier K(+) currents. In the present study, the cellular and subcellular localization of the two delayed rectifier K(+) channels, KCNQ1 and ether...

  10. Induction of a glibenclamide-sensitive K-current by modification of a delayed rectifier channel in rat portal vein in insulinoma cells.

    OpenAIRE

    Edwards, G.; Weston, A. H.

    1993-01-01

    In insulinoma cells (RINm5F), the glibenclamide-sensitive K-current (IK(ATP)) which developed spontaneously or after exposure to levcromakalim or to butanedione monoxime was always accompanied by a reduction in the delayed rectifier current (IK(V)). At potentials over which IK(V) was fully activated, the total outward current remained constant. In rat portal vein, the delayed rectifier channel inhibitor, margatoxin, reduced the combined induction of IK(ATP) and inhibition of IK(V) by levcroma...

  11. Cloning and characterization of a human delayed rectifier potassium channel gene.

    Science.gov (United States)

    Albrecht, B; Lorra, C; Stocker, M; Pongs, O

    1993-01-01

    A human genomic DNA library was screened for sequences homologues to the rat delayed rectifier Kv 2.1 (DRK1) K+ channel cDNA. Three phages were isolated which hybridized to Kv 2.1 cDNA probes. Alignment of the human genomic DNA sequence with the rat cDNA sequence indicated that the open reading frame (ORF) is interrupted by a large intervening sequence, that separates exons encoding the membrane spanning core region of the K+ channel polypeptide. The Kv 2.1 gene occurs once in the human genome and has been mapped to chromosome 20. The human, mouse and rat Kv 2.1 proteins have been highly conserved, showing only a few substitutions outside of the membrane spanning domains in the amino- and carboxy-terminal cytoplasmic domains. Nevertheless, expression of human DRK1 channels in Xenopus oocytes showed that mouse, rat and human Kv 2.1 channels have distinct pharmacological and electrophysiological properties. The observed differences in activation, voltage-dependence, 4-aminopyridine sensitivity and single-channel conductance have to be attributed to amino acid substitutions in the amino-and/or carboxy-terminal cytoplasmic domains. Obviously, these domains of Kv 2.1 channels influence biophysical K+ channel properties, which are thought to be determined solely by the membrane spanning core domain of potassium channels.

  12. Effect of alpha-cypermethrin and theta-cypermethrin on delayed rectifier potassium currents in rat hippocampal neurons.

    Science.gov (United States)

    Tian, Yu-Tao; Liu, Zhao-Wei; Yao, Yang; Yang, Zhuo; Zhang, Tao

    2009-03-01

    Cypermethrin is a photostable synthetic pyrethroid and the most widely used Type II pyrethroid pesticide. The effects of two different stereoisomers of cypermethrin insecticides, alpha-cypermethrin and theta-cypermethrin, on the delayed rectifier potassium current (IK) in hippocampal neurons of rat, were studied using whole-cell patch clamp technique. Alpha-cypermethrin and theta-cypermethrin decreased the amplitude value of IK, and shifted the steady state activation curve of IK towards negative potential at any concentrations (10(-9) M, 10(-8) M, 10(-7) M). Furthermore, at higher concentration, alpha-cypermethrin (10(-7) M) and theta-cypermethrin (10(-8) M, 10(-7) M) had observable effects of the steady state inactivation of IK. The results suggest that IK is the target of alpha-cypermethrin and theta-cypermethrin, which may explain the mechanism of toxic effects of both steroeisomers of cypermethrin on mammalian neurons. Cypermethrin-altered properties of voltage gated delayed rectifier K+ channels may contribute to neurotoxicity by eliciting abnormal electrical discharges in hippocampal CA3 neurons.

  13. Enhancement of delayed-rectifier potassium conductance by low concentrations of local anaesthetics in spinal sensory neurones

    OpenAIRE

    Olschewski, Andrea; Wolff, Matthias; Bräu, Michael E; Hempelmann, Gunter; Vogel, Werner; Safronov, Boris V.

    2002-01-01

    Combining the patch-clamp recordings in slice preparation with the ‘entire soma isolation' method we studied action of several local anaesthetics on delayed-rectifier K+ currents in spinal dorsal horn neurones.Bupivacaine, lidocaine and mepivacaine at low concentrations (1–100 μM) enhanced delayed-rectifier K+ current in intact neurones within the spinal cord slice, while exhibiting a partial blocking effect at higher concentrations (>100 μM). In isolated somata 0.1–10 μM bupivacaine enhanced...

  14. Inhibitory Effects of Glycyrrhetinic Acid on the Delayed Rectifier Potassium Current in Guinea Pig Ventricular Myocytes and HERG Channel

    Directory of Open Access Journals (Sweden)

    Delin Wu

    2013-01-01

    Full Text Available Background. Licorice has long been used to treat many ailments including cardiovascular disorders in China. Recent studies have shown that the cardiac actions of licorice can be attributed to its active component, glycyrrhetinic acid (GA. However, the mechanism of action remains poorly understood. Aim. The effects of GA on the delayed rectifier potassium current (IK, the rapidly activating (IKr and slowly activating (IKs components of IK, and the HERG K+ channel expressed in HEK-293 cells were investigated. Materials and Methods. Single ventricular myocytes were isolated from guinea pig myocardium using enzymolysis. The wild type HERG gene was stably expressed in HEK293 cells. Whole-cell patch clamping was used to record IK (IKr, IKs and the HERG K+ current. Results. GA (1, 5, and 10 μM inhibited IK (IKr, IKs and the HERG K+ current in a concentration-dependent manner. Conclusion. GA significantly inhibited the potassium currents in a dose- and voltage-dependent manner, suggesting that it exerts its antiarrhythmic action through the prolongation of APD and ERP owing to the inhibition of IK (IKr, IKs and HERG K+ channel.

  15. Azimilide causes reverse rate-dependent block while reducing both components of delayed-rectifier current in canine ventricular myocytes.

    Science.gov (United States)

    Gintant, G A

    1998-06-01

    Most class III antiarrhythmic drugs reduce the rapidly activating component of delayed-rectifier current (IKr) without affecting the slowly activating component (IKs). Recently the novel antiarrhythmic agent azimilide (NE-10064) was reported to enhance IKs at low (nanomolar) concentrations and to block both IKr and IKs at higher (micromolar) concentrations. Further to understand the electrophysiologic effects of azimilide, we compared its effects on IKr and IKs (by using whole cell clamp techniques) and action potentials (microelectrode and perforated-patch techniques) on canine ventricular myocytes. A lower azimilide concentration (50 nM) did not enhance IKs. In contrast, a therapeutic azimilide concentration (2 microM) was equieffective in reducing IKr (300-ms isochrones) and IKs (3-s isochrones) by approximately 40% during depolarizing test pulses, as well as reducing IKr (38% decrease) and IKs (33% decrease) tail currents on repolarization. Block of IKs was independent of voltage at positive test potentials. In action-potential studies, 50 nM azimilide had no effect on the action-potential duration (APD), whereas 2 microM azimilide delayed repolarization and caused reverse rate-dependent effects on the APD. Whereas the extent of APD prolongation by azimilide was not correlated with the drug-free APD, azimilide preferentially exaggerated the APD-rate relationship of myocytes displaying the steepest APD-rate relationship under drug-free conditions. In conclusion, therapeutic concentrations of azimilide that cause comparable reduction of canine ventricular IKr and IKs exert reverse rate-dependent effects, which are dependent on the steepness of the APD-rate relationship.

  16. Delayed rectifier and A-type potassium channels associated with Kv 2.1 and Kv 4.3 expression in embryonic rat neural progenitor cells.

    Directory of Open Access Journals (Sweden)

    Dean O Smith

    Full Text Available BACKGROUND: Because of the importance of voltage-activated K(+ channels during embryonic development and in cell proliferation, we present here the first description of these channels in E15 rat embryonic neural progenitor cells derived from the subventricular zone (SVZ. Activation, inactivation, and single-channel conductance properties of recorded progenitor cells were compared with those obtained by others when these Kv gene products were expressed in oocytes. METHODOLOGY/PRINCIPAL FINDINGS: Neural progenitor cells derived from the subventricular zone of E15 embryonic rats were cultured under conditions that did not promote differentiation. Immunocytochemical and Western blot assays for nestin expression indicated that almost all of the cells available for recording expressed this intermediate filament protein, which is generally accepted as a marker for uncommitted embryonic neural progenitor cells. However, a very small numbers of the cells expressed GFAP, a marker for astrocytes, O4, a marker for immature oligodendrocytes, and betaIII-tubulin, a marker for neurons. Using immunocytochemistry and Western blots, we detected consistently the expression of Kv2.1, and 4.3. In whole-cell mode, we recorded two outward currents, a delayed rectifier and an A-type current. CONCLUSIONS/SIGNIFICANCE: We conclude that Kv2.1, and 4.3 are expressed in E15 SVZ neural progenitor cells, and we propose that they may be associated with the delayed-rectifier and the A-type currents, respectively, that we recorded. These results demonstrate the early expression of delayed rectifier and A-type K(+ currents and channels in embryonic neural progenitor cells prior to the differentiation of these cells.

  17. Modulation of the delayed rectifier K+ current in neurons by an angiotensin II type 2 receptor fragment.

    Science.gov (United States)

    Kang, J; Richards, E M; Posner, P; Sumners, C

    1995-01-01

    Angiotensin II (ANG II) stimulates the delayed rectifier K+ current (IK) in neurons cultured from rat hypothalamus and brain stem via AT2 receptors, and this effect involves activation of a Gi protein and protein phosphatase 2A (PP2A). However, there was no evidence that the AT2 receptor involved in this response was the same as the recently cloned AT2 receptor. In the present study, intracellular injection of a 22-amino acid peptide (PEP-22) corresponding to the putative third intracellular loop of the cloned AT2 receptor elicited an increase in IK in cultured neurons that was similar to the effect produced by ANG II. Furthermore, this effect of PEP-22 was abolished by pertussis toxin (200 ng/ml, 24 h) pretreatment and also by superfusion of the PP2A inhibitor okadaic acid (10 nM), suggesting the involvement of Gi protein and PP2A, respectively. Intracellular injection of a random peptide or normal pipette solution did not affect neuronal IK. This is direct evidence to link the cloned AT2 receptor to a defined response elicited by ANG II.

  18. Two components of delayed rectifier K+ current in heart:molecular basis,functional diversity,and contribution to repolarization

    Institute of Scientific and Technical Information of China (English)

    Jian-hua CHENG; Itsuo KODAMA

    2004-01-01

    Delayed rectifier K+ current (IK) is the major outward current responsible for ventricular repolarization. Two components of IK (IKr and IKs) have been identified in many mammalian species including humans. IKr. plays a pivotal role in normal ventricular repolarization. A prolongation of action potential duration (APD) under a variety of conditions would favor the activation of IKs so that to prevent excessive repolarization delay causing early afterdepolarization. The pore-forming α subunits of IKr and IKs are composed of HERG (KCNH2) and KvLQT l (KCNQ l), respectively. KvLQT l is associated with a function-altering β subunit, minK to form IKs. HERG may be associated with minK (KCNE1) and/or minK-related protein (MiRP1) to form IKr, but the issue remains to be established. IKs is enhanced, whereas IKr is usually attenuated by β-adrenergic stimulation via cyclic adenosine 31,51-monophosphate (cAMP)/protein kinase A-dependent pathways. There exist regional differences in the density of IKr and IKs transmurally (endo-epicardial) and along the apico-basal axis, contributing to the spatial heterogeneity of ventricular repolarization. A decrease of IKr or IKs by mutations in either HERG, KvLQTl, or KCNE family results in inherited long QT syndrome (LQTS) with high risk for Torsades de pointes (TdP)-type polymorphic ventricular tachycardia and ventricular fibrillation. As to the pharmacological treatment and prevention of ventricular tachyarrhythmias, selectively block of IKs is expected to be more beneficial than selectively block of IKr in terms of homogeneous prolongation of refractoriness at high heart rates especially in diseased hearts including myocardial ischemia.

  19. Block of the delayed rectifier current (IK) by the 5-HT3 antagonists ondansetron and granisetron in feline ventricular myocytes.

    OpenAIRE

    de Lorenzi, F G; Bridal, T R; Spinelli, W

    1994-01-01

    1. We investigated the effects of two 5-HT3 antagonists, ondansetron and granisetron, on the action potential duration (APD) and the delayed rectifier current (IK) of feline isolated ventricular myocytes. Whole-cell current and action potential recordings were performed at 37 degrees C with the patch clamp technique. 2. Ondansetron and granisetron blocked IK with a KD of 1.7 +/- 1.0 and 4.3 +/- 1.7 microM, respectively. At a higher concentration (30 microM), both drugs blocked the inward rect...

  20. Increase in action potential duration and inhibition of the delayed rectifier outward current IK by berberine in cat ventricular myocytes.

    OpenAIRE

    Sánchez-Chapula, J.

    1996-01-01

    1. In the present work, the effects of the antiarrhythmic drug, berberine, on action potential and ionic currents of cat ventricular myocytes were studied. 2. Berberine prolonged action potential duration in cat ventricular myocytes without altering other variables of the action potential. 3. The drug at concentrations of 0.3-30 microM blocked only the delayed rectifier (IK) current with an IC50 = 4.1 microM. Berberine produced a tonic block and a phasic block that was increased with the dura...

  1. The role of ERK-1/2 in the N/OFQ-induced inhibition of delayed rectifier potassium currents.

    Science.gov (United States)

    Wang, Wei; Cui, Qingbo; Li, Yurong; Li, Baoxin; Yang, Xu; Cui, Lanwei; Jin, Hongbo; Qu, Lihui

    2010-04-16

    Nociceptin/orphanin FQ (N/OFQ) is an endogenous opioid-like heptadecapeptide involved in many neurocognitive functions, including learning and memory. Our previous report showed that N/OFQ inhibits the delayed rectifier potassium current (I(K)), and this effect is associated with protein kinase C (PKC) activation. Therefore, we wanted to determine if extracellular signal-regulated kinase-1/2 (ERK-1/2) signaling is regulated by N/OFQ and associated with the effect of N/OFQ on the I(K). In the current study, we tested if N/OFQ and two PKC activators [phorbol 12,13-dibutyrate (PDBu) and ingenol 3,20-dibenzoate (IDB)] affected the phosphorylation level of ERK-1/2 and its nuclear substrate, ETS-like transcription factor-1 (Elk-1), using western blots. In addition, we tested if ERK-1/2 affected the N/OFQ-induced inhibition of the I(K) by using whole-cell patch-clamp recordings in acutely dissociated rat parietal cortical neurons. We found that N/OFQ, PDBu, and IDB increased the amount of phosphorylated ERK-1/2 and Elk-1; U0126, a specific inhibitor for ERK-1/2, attenuated the inhibitory effect of N/OFQ on the I(K). These data suggest that the ERK-1/2 pathway, at least in part, mediates the inhibitory effect of N/OFQ on the I(K) in acutely dissociated rat cerebral parietal cortical neurons.

  2. Forskolin suppresses delayed-rectifier K+ currents and enhances spike frequency-dependent adaptation of sympathetic neurons.

    Directory of Open Access Journals (Sweden)

    Luis I Angel-Chavez

    Full Text Available In signal transduction research natural or synthetic molecules are commonly used to target a great variety of signaling proteins. For instance, forskolin, a diterpene activator of adenylate cyclase, has been widely used in cellular preparations to increase the intracellular cAMP level. However, it has been shown that forskolin directly inhibits some cloned K+ channels, which in excitable cells set up the resting membrane potential, the shape of action potential and regulate repetitive firing. Despite the growing evidence indicating that K+ channels are blocked by forskolin, there are no studies yet assessing the impact of this mechanism of action on neuron excitability and firing patterns. In sympathetic neurons, we find that forskolin and its derivative 1,9-Dideoxyforskolin, reversibly suppress the delayed rectifier K+ current (IKV. Besides, forskolin reduced the spike afterhyperpolarization and enhanced the spike frequency-dependent adaptation. Given that IKV is mostly generated by Kv2.1 channels, HEK-293 cells were transfected with cDNA encoding for the Kv2.1 α subunit, to characterize the mechanism of forskolin action. Both drugs reversible suppressed the Kv2.1-mediated K+ currents. Forskolin inhibited Kv2.1 currents and IKV with an IC50 of ~32 μM and ~24 µM, respectively. Besides, the drug induced an apparent current inactivation and slowed-down current deactivation. We suggest that forskolin reduces the excitability of sympathetic neurons by enhancing the spike frequency-dependent adaptation, partially through a direct block of their native Kv2.1 channels.

  3. Design and control of an LCL-filter-based three-phase active rectifier

    DEFF Research Database (Denmark)

    Liserre, Marco; Blaabjerg, Frede; Hansen, Steffan

    2005-01-01

    This paper proposes a step-by-step procedure for designing the LCL filter of a front-end three-phase active rectifier. The primary goal is to reduce the switching frequency ripple at a reasonable cost, while at the same time achieving a high-performance front-end rectifier (as characterized...... by a rapid dynamic response and good stability margin). An example LCL filter design is reported and a filter has been built and tested using the values obtained from this design. The experimental results demonstrate the performance of the design procedure both for the LCL filter and for the rectifier...... a powerful tool to design an LCL-filter-based active rectifier while avoiding trial-and-error procedures that can result in having to build several filter prototypes....

  4. Kv3.1-Kv3.2 channels underlie a high-voltage-activating component of the delayed rectifier K+ current in projecting neurons from the globus pallidus.

    Science.gov (United States)

    Hernández-Pineda, R; Chow, A; Amarillo, Y; Moreno, H; Saganich, M; Vega-Saenz de Miera, E C; Hernández-Cruz, A; Rudy, B

    1999-09-01

    The globus pallidus plays central roles in the basal ganglia circuitry involved in movement control as well as in cognitive and emotional functions. There is therefore great interest in the anatomic and electrophysiological characterization of this nucleus. Most pallidal neurons are GABAergic projecting cells, a large fraction of which express the calcium binding protein parvalbumin (PV). Here we show that PV-containing pallidal neurons coexpress Kv3. 1 and Kv3.2 K+ channel proteins and that both Kv3.1 and Kv3.2 antibodies coprecipitate both channel proteins from pallidal membrane extracts solubilized with nondenaturing detergents, suggesting that the two channel subunits are forming heteromeric channels. Kv3.1 and Kv3.2 channels have several unusual electrophysiological properties when expressed in heterologous expression systems and are thought to play special roles in neuronal excitability including facilitating sustained high-frequency firing in fast-spiking neurons such as interneurons in the cortex and the hippocampus. Electrophysiological analysis of freshly dissociated pallidal neurons demonstrates that these cells have a current that is nearly identical to the currents expressed by Kv3.1 and Kv3.2 proteins in heterologous expression systems, including activation at very depolarized membrane potentials (more positive than -10 mV) and very fast deactivation rates. These results suggest that the electrophysiological properties of native channels containing Kv3.1 and Kv3.2 proteins in pallidal neurons are not significantly affected by factors such as associated subunits or postranslational modifications that result in channels having different properties in heterologous expression systems and native neurons. Most neurons in the globus pallidus have been reported to fire sustained trains of action potentials at high-frequency. Kv3.1-Kv3.2 voltage-gated K+ channels may play a role in helping maintain sustained high-frequency repetitive firing as they probably do

  5. BACE1 modulates gating of KCNQ1 (Kv7.1) and cardiac delayed rectifier KCNQ1/KCNE1 (IKs).

    Science.gov (United States)

    Agsten, Marianne; Hessler, Sabine; Lehnert, Sandra; Volk, Tilmann; Rittger, Andrea; Hartmann, Stephanie; Raab, Christian; Kim, Doo Yeon; Groemer, Teja W; Schwake, Michael; Alzheimer, Christian; Huth, Tobias

    2015-12-01

    KCNQ1 (Kv7.1) proteins form a homotetrameric channel, which produces a voltage-dependent K(+) current. Co-assembly of KCNQ1 with the auxiliary β-subunit KCNE1 strongly up-regulates this current. In cardiac myocytes, KCNQ1/E1 complexes are thought to give rise to the delayed rectifier current IKs, which contributes to cardiac action potential repolarization. We report here that the type I membrane protein BACE1 (β-site APP-cleaving enzyme 1), which is best known for its detrimental role in Alzheimer's disease, but is also, as reported here, present in cardiac myocytes, serves as a novel interaction partner of KCNQ1. Using HEK293T cells as heterologous expression system to study the electrophysiological effects of BACE1 and KCNE1 on KCNQ1 in different combinations, our main findings were the following: (1) BACE1 slowed the inactivation of KCNQ1 current producing an increased initial response to depolarizing voltage steps. (2) Activation kinetics of KCNQ1/E1 currents were significantly slowed in the presence of co-expressed BACE1. (3) BACE1 impaired reconstituted cardiac IKs when cardiac action potentials were used as voltage commands, but interestingly augmented the IKs of ATP-deprived cells, suggesting that the effect of BACE1 depends on the metabolic state of the cell. (4) The electrophysiological effects of BACE1 on KCNQ1 reported here were independent of its enzymatic activity, as they were preserved when the proteolytically inactive variant BACE1 D289N was co-transfected in lieu of BACE1 or when BACE1-expressing cells were treated with the BACE1-inhibiting compound C3. (5) Co-immunoprecipitation and fluorescence recovery after photobleaching (FRAP) supported our hypothesis that BACE1 modifies the biophysical properties of IKs by physically interacting with KCNQ1 in a β-subunit-like fashion. Strongly underscoring the functional significance of this interaction, we detected BACE1 in human iPSC-derived cardiomyocytes and murine cardiac tissue and observed

  6. Lithium Carbonate Modulation of Delayed Rectifier Potassium Channel Involves Protein Kinase C/Mitogen-activated Protein Kinase Signaling in Hippocampus of Rats%碳酸锂通过蛋白激酶C/丝裂原活化蛋白激酶信号调节海马神经元延迟整流钾通道

    Institute of Scientific and Technical Information of China (English)

    焦国慧; 刘朝巍; 张涛; 杨卓

    2008-01-01

    碳酸锂可以用于治疗创伤和神经退行性疾病导致的脑部损伤.研究表明其保护效应与蛋白激酶C(PKC)和胞外信号调节激酶(ERK)有关.研究表明PKC激动剂PDBu可以抑制延迟整流钾通道(IK)电流并使其激活电压曲线向超极化方向移动.碳酸锂(50 μmol/L)可以抑制PDBu的反应.进一步的研究表明,预先加入MEK/ERK抑制剂U0126(20 μmol/L),碳酸锂不能逆转PDBu对,IK的作用.因此,PKC和丝裂原活化蛋白激酶(MAPK)/ERK级联反应通路可能在钾离子通道的磷酸化调节中起作用.另外,AC-cAMP和GC-cGMP的交互作用也可能参与碳酸锂对PKC激活作用的调节,成为其神经保护作用的机制之一.%Lithium carbonate could be used to treat or prevent brain damage following traumatic injury and neurodegenerative diseases.It has been shown that its protective effect is related to protein kinase C (PKC) and extracellular signal-related kinase (ERK).It was demonstrated that PDBu,a PKC activator,inhibited amplitudes of delayed rectifier potassium current (It,) and produced a hyperpolarizing shift in the activation-voltage curve.The responses to PDBu were inhibited by lithium carbonate (50μmol/L).Further studies showed that when pretreated with MEK/ERK inhibitor U0126 (20 μmol/L),although PDBu significantly reduced IK,lithium did not reverse the effect of PDBu.Thus,the results suggested that PKC signaling cascades,along with MAPK (mitogen-activated protein kinase) pathway,were required in the phosphorylation of potassium channel,which was presented by regulation of potassium channel characteristic.AC-cAMP and their eross-talk with GC-cGMP pathway could also modulate the effect of lithium on PKC activation,which could be one of underlying mechanisms likely related to neuroprotective effect of lithium.

  7. A 13.56 MHz CMOS Active Rectifier With Switched-Offset and Compensated Biasing for Biomedical Wireless Power Transfer Systems.

    Science.gov (United States)

    Yan Lu; Wing-Hung Ki

    2014-06-01

    A full-wave active rectifier switching at 13.56 MHz with compensated bias current for a wide input range for wirelessly powered high-current biomedical implants is presented. The four diodes of a conventional passive rectifier are replaced by two cross-coupled PMOS transistors and two comparator- controlled NMOS switches to eliminate diode voltage drops such that high voltage conversion ratio and power conversion efficiency could be achieved even at low AC input amplitude |VAC|. The comparators are implemented with switched-offset biasing to compensate for the delays of active diodes and to eliminate multiple pulsing and reverse current. The proposed rectifier uses a modified CMOS peaking current source with bias current that is quasi-inversely proportional to the supply voltage to better control the reverse current over a wide AC input range (1.5 to 4 V). The rectifier was fabricated in a standard 0.35 μm CMOS N-well process with active area of 0.0651 mm(2). For the proposed rectifier measured at |VAC| = 3.0 V, the voltage conversion ratios are 0.89 and 0.93 for RL=500 Ω and 5 kΩ, respectively, and the measured power conversion efficiencies are 82.2% to 90.1% with |VAC| ranges from 1.5 to 4 V for RL=500 Ω.

  8. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  9. Diverse expression of delayed rectifier K+ channel subtype transcripts in several types of smooth muscles of the rat.

    Science.gov (United States)

    Ohya, S; Tanaka, M; Watanabe, M; Maizumi, Y

    2000-06-01

    Diverse expression of voltage dependent K+ (Kv) channels was examined in smooth muscles (SMs); carotid artery (CA), mesenteric artery (MA), urinary bladder (UB), and vas deferens (VD) of the rat, using RT-PCR based analyses. Among eight Kv channel subtypes examined (Kv 1.1, Kv 1.2, Kv 1.5, Kv 1.6, Kv 2.1, Kv 2.2, Kv 3.1, and Kv 3.2), expression of three delayed rectifier Kv (KD) channel (Kv 1.2, Kv 1.5, and Kv 2.1) transcripts was observed in these SMs. To determine precisely the expression levels of the transcripts encoding K(D) subtypes, those of three K(D) subtypes (Kv 1.2, Kv 1.5, and Kv 2.1) were determined by competitive PCR. In vascular SM tissues, CA and MA, Kv 1.2 and Kv 1.5 transcripts were expressed at relatively high levels, whereas in visceral SM tissues, UB and VD, Kv 2.1 transcripts were expressed at the relatively high levels. These results suggest that the diverse expression of K(D) subtypes is, at least in part, responsible for differences in electrical excitability and also for the variation of the electrophysiological and pharmacological phenotypes as tonic and phasic SMs.

  10. Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells

    OpenAIRE

    Sheng-Nan Wu; Ming-Chun Hsu; Yu-Kai Liao; Fang-Tzu Wu; Yuh-Jyh Jong; Yi-Ching Lo

    2012-01-01

    Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (I K(DR)) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of I K(DR) inactivation rate was about 9.8  μ M. Neither linopirdine (10  μ M), NMD...

  11. Bepridil differentially inhibits two delayed rectifier K(+) currents, I(Kr) and I(Ks), in guinea-pig ventricular myocytes.

    Science.gov (United States)

    Wang, J C; Kiyosue, T; Kiriyama, K; Arita, M

    1999-12-01

    1. We investigated the effects of bepridil on the two components of the delayed rectifier K(+) current, i.e., the rapidly activating (I(Kr)) and the slowly activating (I(Ks)) currents using tight-seal whole-cell patch-clamp techniques in guinea-pig ventricular myocytes, under blockade of L-type Ca(2+) current with nitrendipine (5 microM) or D600 (1 microM). 2. Bepridil decreased I(Ks) under blockade of I(Kr) with E4031 (5 microM), in a concentration-dependent manner. The concentration-dependent inhibition of I(Ks) by bepridil was fitted by a curve, assuming one-to-one interactions between the channel and the drug molecule. The concentration of half-maximal inhibition (IC(50)) was found to be 6.2 microM. 3. The effect of bepridil on I(Kr) was assessed using an envelope-of-tails test. In the control condition, a ratio of the tail current to the time-dependent current measured during depolarization was large (>1) at shorter pulses (coefficient=3.03) and the IC(50) was 13.2 microM. 5. These results suggest that bepridil at a clinical therapeutic concentration ( approximately 2 microM) selectively blocks I(Ks) but does not inhibit I(Kr). This may relate to the characteristic frequency-dependent effects of bepridil on the action potential duration (APD), e.g., the non-reverse use-dependent prolongation of APD.

  12. Electric vehicle battery charging algorithm using PMSM windings and an inverter as an active rectifier

    DEFF Research Database (Denmark)

    Zaja, Mario; Oprea, Matei-lon; Suárez, Carlos Gómez

    2014-01-01

    A major setback for large scale electric vehicle market expansion compared to their internal combustion competitors consists in their high price and low driving range. One way of reducing the cost, dimensions and mass of electric vehicles is to eliminate the dedicated AC/DC converter used...... for battery charging. Alternatively, charging could be done using the motor windings as grid side inductors and controlling the inverter to operate as an active boost rectifier. The challenge in this approach is the unequal phase inductances which depend on the rotor position. Another problem appears when...

  13. Single Phase Current-Source Active Rectifier for Traction: Control System Design and Practical Problems

    Directory of Open Access Journals (Sweden)

    Jan Michalik

    2006-01-01

    Full Text Available This research has been motivated by industrial demand for single phase current-source active rectifier dedicated for reconstruction of older types of dc machine locomotives. This paper presents converters control structure design and simulations. The proposed converter control is based on the mathematical model and due to possible interaction with railway signaling and required low switching frequency employs synchronous PWM. The simulation results are verified by experimental tests performed on designed laboratory prototype of power of 7kVA

  14. New drugs targeting the cardiac ultra-rapid delayed-rectifier current (I Kur): rationale, pharmacology and evidence for potential therapeutic value.

    Science.gov (United States)

    Ford, John W; Milnes, James T

    2008-08-01

    There is a clear unmet medical need for new pharmacologic therapies for the treatment of atrial fibrillation (AF) with improved efficacy and safety. This article reviews the development of new and novel Kv1.5/ultra-rapid delayed-rectifier current (I Kur) inhibitors and presents evidence that Kv1.5 modulation provides an atrial-selective mechanism for treating AF. Academia and industry have invested heavily in Kv1.5 (>500 scientific publications and >50 patents published since 1993); however, to realize the full value of this therapeutic drug target, clinical efficacy and safety data are required for a selective Kv1.5 modulator. The reward for demonstrating clinical efficacy and safety in a pivotal Phase 3 trial, on regulatory approval, is "first in class" status.

  15. Predictive Duty Cycle Control of Three-Phase Active-Front-End Rectifiers

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Chen, Wei;

    2016-01-01

    of optimal duty cycles is made by predicting the effect of duty cycles on instantaneous current variations and minimizing the cost function. Due to the adoption of behavior prediction, the proposed controller inherits the excellent dynamic characteristics of predictive controllers. Moreover, the application......This paper proposed an on-line optimizing duty cycle control approach for three-phase active-front-end rectifiers, aiming to obtain the optimal control actions under different operating conditions. Similar to finite control set model predictive control strategy, a cost function previously...... of optimal duty cycles determined by cost function minimization automatically ensures optimum operations of converters within each sampling period. Improved transient and steady-state features of the proposed strategy are confirmed by experimental validations and in-depth comparisons with linear controllers...

  16. Sensitivity analysis of an LCL-filter-based three-phase active rectifier via a virtual circuit approach

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chiarantoni, Ernesto; Aquila, Antonio Dell’;

    2004-01-01

    , to the grid side stiffness and to the parameters of the controller has never been detailed considered. In this paper the experimental results of an LCL-filter-based three-phase active rectifier are analysed with the circuit theory approach. A ?virtual circuit? is synthesized in role of the digital controller...... and of the feedback filters to have an homogenous model that allows a sensitivity analysis which is rigorous and straightforward for the industry....

  17. Inhibition of G protein-activated inwardly rectifying K+ channels by different classes of antidepressants.

    Directory of Open Access Journals (Sweden)

    Toru Kobayashi

    Full Text Available Various antidepressants are commonly used for the treatment of depression and several other neuropsychiatric disorders. In addition to their primary effects on serotonergic or noradrenergic neurotransmitter systems, antidepressants have been shown to interact with several receptors and ion channels. However, the molecular mechanisms that underlie the effects of antidepressants have not yet been sufficiently clarified. G protein-activated inwardly rectifying K(+ (GIRK, Kir3 channels play an important role in regulating neuronal excitability and heart rate, and GIRK channel modulation has been suggested to have therapeutic potential for several neuropsychiatric disorders and cardiac arrhythmias. In the present study, we investigated the effects of various classes of antidepressants on GIRK channels using the Xenopus oocyte expression assay. In oocytes injected with mRNA for GIRK1/GIRK2 or GIRK1/GIRK4 subunits, extracellular application of sertraline, duloxetine, and amoxapine effectively reduced GIRK currents, whereas nefazodone, venlafaxine, mianserin, and mirtazapine weakly inhibited GIRK currents even at toxic levels. The inhibitory effects were concentration-dependent, with various degrees of potency and effectiveness. Furthermore, the effects of sertraline were voltage-independent and time-independent during each voltage pulse, whereas the effects of duloxetine were voltage-dependent with weaker inhibition with negative membrane potentials and time-dependent with a gradual decrease in each voltage pulse. However, Kir2.1 channels were insensitive to all of the drugs. Moreover, the GIRK currents induced by ethanol were inhibited by sertraline but not by intracellularly applied sertraline. The present results suggest that GIRK channel inhibition may reveal a novel characteristic of the commonly used antidepressants, particularly sertraline, and contributes to some of the therapeutic effects and adverse effects.

  18. Forskolin Suppresses Delayed-Rectifier K+ Currents and Enhances Spike Frequency-Dependent Adaptation of Sympathetic Neurons

    OpenAIRE

    Luis I Angel-Chavez; Eduardo I Acosta-Gómez; Mario Morales-Avalos; Elena Castro; Humberto Cruzblanca

    2015-01-01

    In signal transduction research natural or synthetic molecules are commonly used to target a great variety of signaling proteins. For instance, forskolin, a diterpene activator of adenylate cyclase, has been widely used in cellular preparations to increase the intracellular cAMP level. However, it has been shown that forskolin directly inhibits some cloned K+ channels, which in excitable cells set up the resting membrane potential, the shape of action potential and regulate repetitive firing....

  19. Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K(+) current in human atrial myocytes.

    Science.gov (United States)

    Wang, Huan; Wang, Hong-Fei; Wang, Chen; Chen, Yu-Fang; Ma, Rong; Xiang, Ji-Zhou; Du, Xin-Ling; Tang, Qiang

    2016-10-15

    In the present study, the inhibitory effects of hesperetin (HSP) on human cardiac Kv1.5 channels expressed in HEK 293 cells and the ultra-rapid delayed rectifier K(+) current (Ikur) in human atrial myocytes were examined by using the whole-cell configuration of the patch-clamp techniques. We found that hesperetin rapidly and reversibly suppressed human Kv1.5 current in a concentration dependent manner with a half-maximal inhibition (IC50) of 23.15 μΜ with a Hill coefficient of 0.89. The current was maximally diminished about 71.36% at a concentration of 300μM hesperetin. Hesperetin significantly positive shifted the steady-state activation curve of Kv1.5, while negative shifted the steady-state inactivation curve. Hesperetin also accelerated the inactivation and markedly slowed the recovery from the inactivation of Kv1.5 currents. Block of Kv1.5 currents by hesperetin was in a frequency dependent manner. However, inclusion of 30μM hesperetin in pipette solution produced no effect on Kv1.5 channel current, while the current were remarkable and reversibly inhibited by extracellular application of 30μM hesperetin. We also found that hesperetin potently and reversibly inhibited the ultra-repaid delayed K(+) current (Ikur) in human atrial myocytes, which is in consistent with the effects of hesperetin on Kv1.5 currents in HEK 293 cells. In conclusion, hesperetin is a potent inhibitor of Ikur (which is encoded by Kv1.5), with blockade probably due to blocking of both open state and inactivated state channels from outside of the cell.

  20. A comparison of currents carried by HERG, with and without coexpression of MiRP1, and the native rapid delayed rectifier current. Is MiRP1 the missing link?

    Science.gov (United States)

    Weerapura, Manjula; Nattel, Stanley; Chartier, Denis; Caballero, Ricardo; Hébert, Terence E

    2002-04-01

    Although it has been suggested that coexpression of minK related peptide (MiRP1) is required for reconstitution of native rapid delayed-rectifier current (I(Kr)) by human ether-a-go-go related gene (HERG), currents resulting from HERG (I(HERG)) and HERG plus MiRP1 expression have not been directly compared with native I(Kr). We compared the pharmacological and selected biophysical properties of I(HERG) with and without MiRP1 coexpression in Chinese hamster ovary (CHO) cells with those of guinea-pig I(Kr) under comparable conditions. Comparisons were also made with HERG expressed in Xenopus oocytes. MiRP1 coexpression significantly accelerated I(HERG) deactivation at potentials negative to the reversal potential, but did not affect more physiologically relevant deactivation of outward I(HERG), which remained slower than that of I(Kr). MiRP1 shifted I(HERG) activation voltage dependence in the hyperpolarizing direction, whereas I(Kr) activated at voltages more positive than I(HERG). There were major discrepancies between the sensitivity to quinidine, E-4031 and dofetilide of I(HERG) in Xenopus oocytes compared to I(Kr), which were not substantially affected by coexpression with MiRP1. On the other hand, the pharmacological sensitivity of I(HERG) in CHO cells was indistinguishable from that of I(Kr) and was unaffected by MiRP1 coexpression. We conclude that the properties of I(HERG) in CHO cells are similar in many ways to those of native I(Kr) under the same recording conditions, and that the discrepancies that remain are not reduced by coexpression with MiRP1. These results suggest that the physiological role of MiRP1 may not be to act as an essential consituent of the HERG channel complex carrying native I(Kr).

  1. Accumulation of slowly activating delayed rectifier potassium current (IKs) in canine ventricular myocytes

    DEFF Research Database (Denmark)

    Stengl, Milan; Volders, Paul G A; Thomsen, Morten Bækgaard

    2003-01-01

    the deactivation is much faster, is still unclear. In this study the conditions under which accumulation occurs in canine ventricular myocytes were studied with regard to its physiological relevance in controlling action potential duration (APD). At baseline, square pulse voltage clamp experiments revealed...... that the accumulation of canine IKs could occur, but only at rather short interpulse intervals (action potential (AP) clamp commands of constant duration (originally recorded at rate of 2 Hz), an accumulation was only found at interpulse intervals close to 0 ms. Transmembrane potential recordings......, but this lengthening was reverse rate dependent. AP clamp experiments in a physiologically relevant setting (short, high rate APs delivered at a corresponding rate) revealed a limited accumulation of IKs in the presence of isoproterenol. In conclusion, a physiologically relevant accumulation of IKs was only observed...

  2. Some Topologies of High Quality Rectifiers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Several basic classes of three-phase high-quality rectifiers are described.Both single-switch and six-switch three-phase rectifier topologiescan be derived from parent dc-dc converters.Single-switch rectifiers are compared with the basic six-switch PWM rectifiers performingsimilar power conversion functions,using the measures of total semiconductor stress and active semiconductor utilization.The singleswitchapproach is shown to utilize the semiconductor devices more effectively.Zero current switching and multiresonant approaches are foundto exhibit low switch stress over a wide range of operating points,with lowTHD.

  3. Photophysics of thermally activated delayed fluorescence molecules

    Science.gov (United States)

    Dias, Fernando B.; Penfold, Thomas J.; Monkman, Andrew P.

    2017-03-01

    Thermally activated delayed fluorescence (TADF) has recently emerged as one of the most attractive methods for harvesting triplet states in metal-free organic materials for application in organic light emitting diodes (OLEDs). A large number of TADF molecules have been reported in the literature with the purpose of enhancing the efficiency of OLEDs by converting non-emissive triplet states into emissive singlet states. TADF emitters are able to harvest both singlets and triplet states through fluorescence (prompt and delayed), the latter due to the thermally activated reverse intersystem crossing mechanism that allows up-conversion of low energy triplet states to the emissive singlet level. This allows otherwise pure fluorescent OLEDs to overcome their intrinsic limit of 25% internal quantum efficiency (IQE), which is imposed by the 1:3 singlet–triplet ratio arising from the recombination of charges (electrons and holes). TADF based OLEDS with IQEs close to 100% are now routinely fabricated in the green spectral region. There is also significant progress for blue emitters. However, red emitters still show relatively low efficiencies. Despite the significant progress that has been made in recent years, still significant challenges persist to achieve full understanding of the TADF mechanism and improve the stability of these materials. These questions need to be solved in order to fully implement TADF in OLEDs and expand their application to other areas. To date, TADF has been exploited mainly in the field of OLEDs, but applications in other areas, such as sensing and fluorescence microscopies, are envisaged. In this review, the photophysics of TADF molecules is discussed, summarising current methods to characterise these materials and the current understanding of the TADF mechanism in various molecular systems.

  4. Short-term desensitization of G-protein-activated, inwardly rectifying K+ (GIRK) currents in pyramidal neurons of rat neocortex.

    Science.gov (United States)

    Sickmann, Thomas; Alzheimer, Christian

    2003-10-01

    Whole cell recordings from acutely isolated rat neocortical pyramidal cells were performed to study the kinetics and the mechanisms of short-term desensitization of G-protein-activated, inwardly rectifying K+ (GIRK) currents during prolonged application (5 min) of baclofen, adenosine, or serotonin. Most commonly, desensitization of GIRK currents was characterized by a biphasic time course with average time constants for fast and slow desensitization in the range of 8 and 120 s, respectively. The time constants were independent of the agonist used to evoke the current. The biphasic time course was preserved in perforated-patch recordings, indicating that neither component of desensitization is attributable to cell dialysis. Desensitization of GIRK currents displayed a strong heterologous component in that application of a second agonist substantially reduced the responsiveness to a test agonist. Fast desensitization, but not slow desensitization, was lost in cells loaded with GDP, suggesting that the hydrolysis cycle of G proteins might underlie the initial, rapid current decline. Hydrolysis of phosphatidylinositol biphosphate is an unlikely candidate underlying short-term desensitization, because both components of desensitization were preserved in the presence of the phospholipase C inhibitor U73122. We conclude that short-term desensitization does neither result from receptor downregulation nor from altered channel gating but might involve modifications of the G-protein-dependent pathway that serves to translate receptor activation into channel opening.

  5. Stability Improvements of an LCL-filter based Three-phase Active Rectifier

    DEFF Research Database (Denmark)

    Liserre, Marco; Dell'Aquila, Antonio; Blaabjerg, Frede

    2002-01-01

    for the ac inductors making them expensive and bulky. Moreover the dynamic of the system becomes poor with so high value of inductance. On the contrary to adopt an LCL-filter configuration allows to use reduced values of the inductances (preserving dynamic) and to reduce the switching frequency pollution......, both passive (based on the use of resistors) and active (based on the modification of the control algorithm), is studied using the z-plane root locus approach and looking to dynamic performances and losses. In fact it is necessary to verify the dynamic effects by the introduction of damping resistors...

  6. An Inductorless Self-Controlled Rectifier for Piezoelectric Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Shaohua Lu

    2015-11-01

    Full Text Available This paper presents a high-efficiency inductorless self-controlled rectifier for piezoelectric energy harvesting. High efficiency is achieved by discharging the piezoelectric device (PD capacitance each time the current produced by the PD changes polarity. This is achieved automatically without the use of delay lines, thereby making the proposed circuit compatible with any type of PD. In addition, the proposed rectifier alleviates the need for an inductor, making it suitable for on-chip integration. Reported experimental results show that the proposed rectifier can harvest up to 3.9 times more energy than a full wave bridge rectifier.

  7. SPS rectifier stations

    CERN Multimedia

    1974-01-01

    The first of the twelves SPS rectifier stations for the bending magnets arrived at CERN at the end of the year. The photograph shows a station with the rectifiers on the left and in the other three cubicles the chokes, capacitors and resistor of the passive filter.

  8. Bis(7)-tacrine/tacrine对大鼠DRG神经元延时整流钾通道电流的调制作用%Inhibitory effect of Bis(7)-tacrine/tacrine on delayed rectified potassium currents in rat DRG neurons

    Institute of Scientific and Technical Information of China (English)

    李享元; 李之望

    2012-01-01

    目的 研究乙酰胆碱酯酶抑制剂bis(7)-tacrine/tacrine[bis(7)-tetrahydroaminacrine]对大鼠DRG神经元的延时整流钾通道电流的调制作用.方法 在急性分离的DRG神经元标本上,采用全细胞膜片钳技术记录钾通道电流,研究bis(7)-tacrine/tacrine对DRG神经元延时整流钾通道电流的影响和作用.结果 bis(7)-tacrine对延迟整流钾通道电流IDR具有浓度依赖性的抑制作用,其半量效浓度为(IC50)(0.72±0.05)μmol*L-1,而tacrine抑制的半量效浓度(IC50)(58.3±3.7)μmol*L-1.结论 两种药物对DRG延时整流钾通道电流有浓度依赖性的抑制作用,bis(7)-tacrine的抑制强度高一个数量级,有利于抑制神经元的钾通道过于激活和兴奋,预防胞内钾离子过度丢失而引起的神经元凋亡,起到神经保护的作用.%Aim To investigate modulatory effect of bis ( 7 )-tacrine [ bis ( 7 )-tetrahydroaminacrine ], a novel dimeric AChE inhibitor, on rat DRG delayed rectified potassium channels. Methods Experiments were per -formed on neurons acutely isolated from rat dorsal root ganglion ( DRG ) potassium channels, and the delayed rectified currents ( IDR ) were recorded with whole-cell patch clamp technique. Results IDR were inhibited by bis( 7 )-tacrine, which were much more potent ( IC50 = 0. 72 ±0. 05 μmol · L-1 for IDR ) than those by tacrine ( IC50 =58. 3 ± 3. 7 μmol · L-1 for IDR ). bis( 7 )-tac-rine ( 1 μmol · L-1 ) shifts steady state activation curve and inactivation curve of IDR to the hyperpolar-izing direction. Conclusions The inhibitory effect of bis( 7 )-tacrine on IDR may be attributed to reduction of potential ranges of steady state activation and inactivation and delay of decay phase. Drugs may prevent loss of potassium ions and excitory toxicosis for neuron, and may be neuroprotective in A. D treatment.

  9. Do Longer Delays Matter? The Effect of Prolonging Delay in CTL Activation

    CERN Document Server

    Gallegos, Angela

    2010-01-01

    The activation of a specific immune response takes place in the lymphoid organs such as the spleen. We present here a simplified model of the proliferation of specific immune cells in the form of a single delay equation. We show that the system can undergo switches in stability as the delay is increased, and we interpret these results in the context of sustaining an effective immune response to a dendritic cell vaccine.

  10. Effect of tanshinone ⅡA on delayed rectifier potassium channels in guinea pig hypertrophic myocardium%丹参酮ⅡA对豚鼠肥厚心肌延迟整流钾通道的影响

    Institute of Scientific and Technical Information of China (English)

    唐昱; 盛国太; 葛郁芝; 王云霞; 曹乾强; 周裔忠; 张繁之

    2012-01-01

    AIM: To illuminate the underlying mechanism of tanshinone II A in preventing myocardial hypertrophy - induced arrythmia by observing the effect of tanshinone on rapidly and slowly activating components of delayed rectifier potassium currents ( Ikr and Iks ). METHODS: Hypertrophic guinea pig model was made by abdomen aorta constriction. The guinea pigs were randomly divided into sham operation group, cardiac hypertrophy group, low - dose tanshinone group ( 10 mg · kg-1 · d-1 ), high -dose tanshinone group ( 20 mg · kg-1 · d-1 ) and valsartan group ( 10 mg · kg-1 · d -1 ) ( 12 animals in each group ). The action potential duration and densities of Ikr and Iks in cellular membrane in each group were observed by patch clamp technique. RESULTS: After 4 weeks, the blood pressure in the operation groups was obviously higher than that in sham operation group ( P 0. 05 ). The membrane capacitance and action potential duration were much higher in hypertrophy group than those in sham operation group ( P 0. 05 ). CONCLUSION: Tanshinone IA decreases the densities of Ikr and Iks in the hypertrophic cardiocytes, which may be the related mechanism of its antiarrhyth-mic effects.%目的:通过研究丹参酮ⅡA(TSN)对豚鼠肥厚心肌细胞快激活延迟整流钾电流(IKr)和慢激活延迟整流钾电流(IKs)的影响,在离子通道水平探讨丹参酮ⅡA抗肥厚心肌心律失常的机制.方法:采用腹主动脉结扎技术制造心肌肥厚模型,将豚鼠随机分为假手术组(A组)、肥厚模型组(B组)、低剂量丹参组(C组,10 mg·kg-1·d-1)、高剂量丹参组(D组,20 mg·kg-1·d-1)和缬沙坦治疗组(E组,10 mg·kg-1·d-1),每组12只.通过应用标准的全细胞膜片钳技术记录各实验组心肌细胞膜上动作电位时程(APD)、IKs和IKr密度的变化.结果:(1)与A组相比,B组、C组、D组和E组手术后4周血压均明显升高,差异有显著差异(P<0.01),B、C、D和E组间血压无显著差异(P>0.05).(2)与A组相

  11. BmT×3B, a novel scorpion toxin from Buthus martensi Karsch, inhibits delayed rectifier potassium current in rat hippocampal neurons%东亚钳蝎中新分离的毒素BmT×3B抑制大鼠海马神经元延迟整流性钾电流

    Institute of Scientific and Technical Information of China (English)

    李明华; 王跃丰; 陈学勤; 张乃霞; 吴厚铭; 胡国渊

    2003-01-01

    目的:研究从东亚钳蝎毒素中新分离的短肽BmTx3B对电压门控性钾通道的作用.方法:在酶解打散的新生大鼠海马细胞,采用全细胞电压箝位方式记录,并根据动力学特性分离二种电压依赖性钾电流.结果:BmTx3B(10-100 μmol/L)选择地抑制延迟整流性钾电流(IK),不影响瞬时性快钾电流(IA).此抑制作用是可逆的,呈现浓度依赖性,但无电压依赖性.BmTx3B对延迟整流性钾电流的稳态激活和稳态失活的动力学特性无影响.结论:蝎毒短肽BmTx3B选择地抑制海马神经元延迟整流性钾通道.%AIM: To examine the effect of BmTx3B, a novel short-chain peptide isolated from the venom of Asian scorpion Buthus martensi Karsch, on voltage-gated potassium channels. METHODS: Two types of voltage-dependent potassium currents were recorded from dissociated hippocampal neurons of neonatal rat in whole-cell voltageclamp mode, and separated based upon their kinetic properties. RESULTS: BmTx3B (10-100μmol/L) selectively inhibited the delayed rectifier potassium current (IK), without affecting the fast transient potassium current (IA).The inhibition of the peptide on IK was reversible, concentration-dependent and voltage-independent. BmTx3B did not affect the steady-state activation and inactivation kinetics of the current. CONCLUSION: The short-chain scorpion peptide BmTx3B selectively blocked the delayed rectifier potassium channel.

  12. Rectifier cabinet static breaker

    Science.gov (United States)

    Costantino, Jr, Roger A.; Gliebe, Ronald J.

    1992-09-01

    A rectifier cabinet static breaker replaces a blocking diode pair with an SCR and the installation of a power transistor in parallel with the latch contactor to commutate the SCR to the off state. The SCR serves as a static breaker with fast turnoff capability providing an alternative way of achieving reactor scram in addition to performing the function of the replaced blocking diodes. The control circuitry for the rectifier cabinet static breaker includes on-line test capability and an LED indicator light to denote successful test completion. Current limit circuitry provides high-speed protection in the event of overload.

  13. 三相电压型PWM整流器自抗扰控制%Active Disturbance Rejection Control of Three-Phase Voltage Source PWM Rectifiers

    Institute of Scientific and Technical Information of China (English)

    刘子建; 吴敏; 王春生; 桂武鸣; 陈鑫

    2011-01-01

    Based on the nonlinear characteristic of three-phase voltage source PWM rectifiers, a nonlinear control strategy is proposed. The voltage and current controllers are designed by using active disturbance rejection control (ADRC) technique, and then, the controllers have the advantage of robustness. The load disturbance is compensated by the voltage controller, which effectively removes the static tracking error of the output direct current (DC) voltage, which is caused by the disturbance. The switching signals of the three-phase voltage source PWM rectifiers are generated by space vector pulse width modulation (PWM) method. Simulation results show the effectiveness of the presented control strategy.%针对三相电压型PWM整流器本身的非线性特点,提出一种非线性控制策略.采用自抗扰控制技术设计了电压和电流控制器,具有鲁棒性强的特点.通过电压控制器对负载扰动进行补偿,消除了负载扰动带来的输出直流电压稳态跟踪误差.三相电压型PWM整流器的开关信号利用空间矢量脉宽调制方法生成.仿真结果表明,本文所提控制策略是有效的,

  14. Genetic Algorithm-Based Design of the Active Damping for an LCL-Filter Three-Phase Active Rectifier

    DEFF Research Database (Denmark)

    Liserre, Marco; Aquila, Antonio Dell; Blaabjerg, Frede

    2004-01-01

    of this filter is easily done, for a wide range of sampling frequencies, with the use of genetic algorithms. This method is used only for the optimum choice of the parameters in the filter, and an on-line implementation is not needed. Thus the resulting active damping solution does not need new sensors...

  15. Open channel block of A-type, kv4.3, and delayed rectifier K+ channels, Kv1.3 and Kv3.1, by sibutramine.

    Science.gov (United States)

    Kim, Sung Eun; Ahn, Hye Sook; Choi, Bok Hee; Jang, Hyun-Jong; Kim, Myung-Jun; Rhie, Duck-Joo; Yoon, Shin-Hee; Jo, Yang-Hyeok; Kim, Myung-Suk; Sung, Ki-Wug; Hahn, Sang June

    2007-05-01

    The effects of sibutramine on voltage-gated K+ channel (Kv)4.3, Kv1.3, and Kv3.1, stably expressed in Chinese hamster ovary cells, were investigated using the whole-cell patch-clamp technique. Sibutramine did not significantly decrease the peak Kv4.3 currents, but it accelerated the rate of decay of current inactivation in a concentration-dependent manner. This phenomenon was effectively characterized by integrating the total current over the duration of a depolarizing pulse to +40 mV. The IC50 value for the sibutramine block of Kv4.3 was 17.3 microM. Under control conditions, the inactivation of Kv4.3 currents could be fit to a biexponential function, and the time constants for the fast and slow components were significantly decreased after the application of sibutramine. The association (k+1) and dissociation (k-1) rate constants for the sibutramine block of Kv 4.3 were 1.51 microM-1s-1 and 27.35 s-1, respectively. The theoretical KD value, derived from k-1/k+1, yielded a value of 18.11 microM. The block of Kv4.3 by sibutramine displayed a weak voltage dependence, increasing at more positive potentials, and it was use-dependent at 2 Hz. Sibutramine did not affect the time course for the deactivating tail currents. Neither steady-state activation and inactivation nor the recovery from inactivation was affected by sibutramine. Sibutramine caused the concentration-dependent block of the Kv1.3 and Kv3.1 currents with an IC50 value of 3.7 and 32.7 microM, respectively. In addition, sibutramine reduced the tail current amplitude and slowed the deactivation of the tail currents of Kv1.3 and Kv3.1, resulting in a crossover phenomenon. These results indicate that sibutramine acts on Kv4.3, Kv1.3, and Kv3.1 as an open channel blocker.

  16. Performance enhancement of the single-phase series active filter by employing the load voltage waveform reconstruction and line current sampling delay reduction methods

    DEFF Research Database (Denmark)

    Senturk, O.S.; Hava, A.M.

    2011-01-01

    This paper proposes the waveform reconstruction method (WRM), which is utilized in the single-phase series active filter's (SAF's) control algorithm, in order to extract the load harmonic voltage component of voltage harmonic type single-phase diode rectifier loads. Employing WRM and the line...... current sampling delay reduction method, a single-phase SAF compensated system provides higher harmonic isolation performance and higher stability margins compared to the system using conventional synchronous-reference-frame-based methods. The analytical, simulation, and experimental studies of a 2.5 k......W single-phase SAF compensated system prove the theory....

  17. Topology optimization of viscoelastic rectifiers

    DEFF Research Database (Denmark)

    Jensen, Kristian Ejlebjærg; Szabo, Peter; Okkels, Fridolin

    2012-01-01

    An approach for the design of microfluidic viscoelastic rectifiers is presented based on a combination of a viscoelastic model and the method of topology optimization. This presumption free approach yields a material layout topologically different from experimentally realized rectifiers...

  18. Mitochondrial ATP-sensitive potassium channel activity and hypoxic preconditioning are independent of an inwardly rectifying potassium channel subunit in Caenorhabditis elegans.

    Science.gov (United States)

    Wojtovich, Andrew P; DiStefano, Peter; Sherman, Teresa; Brookes, Paul S; Nehrke, Keith

    2012-02-17

    Hypoxic preconditioning (HP) is an evolutionarily-conserved mechanism that protects an organism against stress. The mitochondrial ATP-sensitive K(+) channel (mK(ATP)) plays an essential role in the protective signaling, but remains molecularly undefined. Several lines of evidence suggest that mK(ATP) may arise from an inward rectifying K(+) channel (Kir). The genetic model organism Caenorhabditis elegans exhibits HP and displays mK(ATP) activity. Here, we investigate the tissue expression profile of the three C. elegans Kir genes and demonstrate that mutant strains where the irk genes have been deleted either individually or in combination can be protected by HP and exhibit robust mK(ATP) channel activity in purified mitochondria. These data suggest that the mK(ATP) in C. elegans does not arise from a Kir derived channel.

  19. Mitochondrial ATP-sensitive potassium channel activity and hypoxic preconditioning are independent of an inwardly rectifying potassium channel subunit in C. elegans

    Science.gov (United States)

    Wojtovich, Andrew P.; DiStefano, Peter; Sherman, Teresa; Brookes, Paul S.; Nehrke, Keith

    2012-01-01

    Hypoxic preconditioning (HP) is an evolutionarily-conserved mechanism that protects an organism against stress. The mitochondrial ATP-sensitive K+ channel (mKATP) plays an essential role in the protective signaling, but remains molecularly undefined. Several lines of evidence suggest that mKATP may arise from an inward rectifying K+ channel (Kir). The genetic model organism C. elegans exhibits HP and displays mKATP activity. Here, we investigate the tissue expression profile of the three C. elegans Kir genes and demonstrate that mutant strains where the irk genes have been deleted either individually or in combination can be protected by HP and exhibit robust mKATP channel activity in purified mitochondria. These data suggest that the mKATP in C. elegans does not arise from a Kir derived channel. PMID:22281198

  20. Modified active disturbance rejection control for time-delay systems.

    Science.gov (United States)

    Zhao, Shen; Gao, Zhiqiang

    2014-07-01

    Industrial processes are typically nonlinear, time-varying and uncertain, to which active disturbance rejection control (ADRC) has been shown to be an effective solution. The control design becomes even more challenging in the presence of time delay. In this paper, a novel modification of ADRC is proposed so that good disturbance rejection is achieved while maintaining system stability. The proposed design is shown to be more effective than the standard ADRC design for time-delay systems and is also a unified solution for stable, critical stable and unstable systems with time delay. Simulation and test results show the effectiveness and practicality of the proposed design. Linear matrix inequality (LMI) based stability analysis is provided as well.

  1. Time Delay Evolution of Five Active Galactic Nuclei

    Indian Academy of Sciences (India)

    A. Kovačević; L. Č. Popović; A. I. Shapovalova; D. Ilić; A. N. Burenkov; V. H. Chavushyan

    2015-12-01

    Here we investigate light curves of the continuum and emission lines of five type 1 active galactic nuclei (AGN) from our monitoring campaign, to test time-evolution of their time delays. Using both modeled and observed AGN light curves, we apply Gaussian kernel-based estimator to capture variation of local patterns of their time evolving delays. The largest variations of time delays of all objects occur in the period when continuum or emission lines luminosity is the highest. However, Gaussian kernel-based method shows instability in the case of NGC 5548, 3C 390.3, E1821+643 and NGC 4051 possibly due to numerical discrepancies between damped random walk (DRW) time scale of light curves and sliding time windows of the method. The temporal variations of time lags of Arp 102B can correspond to the real nature of the time lag evolution.

  2. On the time delay evolution of five Active Galactic Nuclei

    CERN Document Server

    Kovacevic, Andjelka; Shapovalova, Alla I; Ilic, Dragana; Burenkov, Aleksandr N; Chavushyan, Vahram H

    2015-01-01

    Here we investigate light curves of the continuum and emission lines of five type 1 active galactic nuclei (AGN) from our monitoring campaign, to test time-evolution of their time delays.Using both modeled and observed AGN light curves we apply Gaussian-kernel based estimator to capture variation of local patterns of their time evolving delays. The largest variations of time delays of all objects occur in the period when continuum or emission lines luminosity is the highest. However, Gaussian kernel based method shows instability in the case of NGC 5548, 3C 390.3, E1821+643 and NGC 4051 possible due to numerical discrepancies between Damped Random Walk (DRW) time scale of light curves and sliding time windows of the method. The temporal variations of time lags of Arp 102B can correspond to the real nature of the time lag evolution.

  3. EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier

    Directory of Open Access Journals (Sweden)

    R. Dolecek

    2008-12-01

    Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.

  4. Solid state thermal rectifier

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-07-05

    Thermal rectifiers using linear nanostructures as core thermal conductors have been fabricated. A high mass density material is added preferentially to one end of the nanostructures to produce an axially non-uniform mass distribution. The resulting nanoscale system conducts heat asymmetrically with greatest heat flow in the direction of decreasing mass density. Thermal rectification has been demonstrated for linear nanostructures that are electrical insulators, such as boron nitride nanotubes, and for nanostructures that are conductive, such as carbon nanotubes.

  5. Effects of 50 Hz Magnetic Fields With Different Intensities Exposure on Delayed Rectifier Potassium Channel of Neurons%不同强度工频磁场对神经元延迟整流钾通道特性的影响

    Institute of Scientific and Technical Information of China (English)

    李刚; 李丹丹; 李媛媛; 林凌

    2012-01-01

    There is a growing concern about the relationship between the human health and the biological effects caused by the magnetic fields exposure. The cortical neurons isolated from the mice were exposed to 50 Hz magnetic fields (EMF 1 mT, 5 mT, 10 mT) for 15 min, and then the currents of the delayed rectifier potassium channel were recorded off-line using the whole-cell patch clamp technique to investigate the effects of EMF on channels for the first time. Compared to the control group, there was a significant inhibition on the Ik after exposure to EMF, and with the increase of the voltage depolarization, the inhibition rates of 1 mT and 5 mT almost unchanged and the inhibition rates were (30.0 ± 4.2)% and (20.0 ± 2.2)%, respectively. While the inhibition rate of 10 mT became larger and the maximum inhibition rate was 43.4%. Additionally, 1 mT and 5 mT magnetic fields both affected the activation characteristics of delayed rectifier potassium channel, the half activation voltage became larger and the slope factor unchanged, while 10 mT magnetic fields did not changed anything. This paper indicated that the structure and function of the channel protein on cell membrane may be altered by 50 Hz EMF, and there were different effects on the channel for different strength of magnetic fields, the window effects of strength of magnetic fields were improved in this study.%工频磁场是人类生活中接触最多的一类磁场,其引起的生物效应与人类健康的关系备受关注.本文选用1 mT、5 mT及10mT工频磁场照射急性分离的小鼠皮层神经元(15 min),应用全细胞膜片钳技术离线记录通道电流,研究了工频磁场对神经元延迟整流钾通道特性的影响.结果显示,1 mT、5mT及10 mT3个强度的工频磁场对Iκ均有抑制作用,但随着去极化电压的增加,发现1 mT和5 mT工频磁场的抑制率几乎不变,抑制率分别为(30±4.2)%和(20±2.2)%,而10 mT工频磁场的抑制率增加,最大抑制率为43.4

  6. Finite-time robust stabilization of uncertain delayed neural networks with discontinuous activations via delayed feedback control.

    Science.gov (United States)

    Wang, Leimin; Shen, Yi; Sheng, Yin

    2016-04-01

    This paper is concerned with the finite-time robust stabilization of delayed neural networks (DNNs) in the presence of discontinuous activations and parameter uncertainties. By using the nonsmooth analysis and control theory, a delayed controller is designed to realize the finite-time robust stabilization of DNNs with discontinuous activations and parameter uncertainties, and the upper bound of the settling time functional for stabilization is estimated. Finally, two examples are provided to demonstrate the effectiveness of the theoretical results.

  7. Predictive active disturbance rejection control for processes with time delay.

    Science.gov (United States)

    Zheng, Qinling; Gao, Zhiqiang

    2014-07-01

    Active disturbance rejection control (ADRC) has been shown to be an effective tool in dealing with real world problems of dynamic uncertainties, disturbances, nonlinearities, etc. This paper addresses its existing limitations with plants that have a large transport delay. In particular, to overcome the delay, the extended state observer (ESO) in ADRC is modified to form a predictive ADRC, leading to significant improvements in the transient response and stability characteristics, as shown in extensive simulation studies and hardware-in-the-loop tests, as well as in the frequency response analysis. In this research, it is assumed that the amount of delay is approximately known, as is the approximated model of the plant. Even with such uncharacteristic assumptions for ADRC, the proposed method still exhibits significant improvements in both performance and robustness over the existing methods such as the dead-time compensator based on disturbance observer and the Filtered Smith Predictor, in the context of some well-known problems of chemical reactor and boiler control problems.

  8. Rectified Forces in Rubidium

    Science.gov (United States)

    Grove, Timothy Todd

    The forces exerted on a three-level atom by a bichromatic standing-wave field are investigated. A theoretical analysis shows that the standing-wave dipole force can be rectified, i.e., maintain its sign over many optical wavelengths. Three systems in particular are studied: the lambda, the vee, and the cascade. Experimental results for the rubidium 5S --> 5P --> 5D cascade system are used to confirm the theory. The nearly coincident transition wavelengths for this system (780.0 nm and 776.0 nm) provide potential wells repeating at the beat wavelength (71 μm) which can accumulate laser cooled atoms. This force may have future applications in forming deep neutral atom traps as well as in the creation of new elements for atom optics. Two-color, two-photon spectroscopy of the 5D_{5/2}cascade system (5S --> 5P --> 5D) was also performed.

  9. Effect of temperature on rectified diffusion during ultrasound-induced heating.

    Science.gov (United States)

    Webb, Ian R; Payne, Stephen J; Coussios, Constantin-C

    2011-11-01

    Experimental observations of delayed-onset cavitation during ultrasound insonation have been suggested as being caused by a change in the size distribution of the bubble population due to rectified diffusion. To investigate this hypothesis, a single bubble model is used here to explore the effect of heating and the subsequent elevated temperatures on the rectified diffusion process. Numerical solution of the model, which includes the temperature dependences of seven relevant physical parameters, allows quantification of the change in the pressure threshold for rectified diffusion, as well as the importance of the bulk liquid saturation concentration in determining bubble evolution. Although elevated temperatures and liquid supersaturation reduce the rectified diffusion threshold, it remains coincident with the inertial cavitation thresholds at submicron bubble sizes at all temperatures. This observation suggests that changes in the nucleation environment, rather than bubble growth due to rectified diffusion, is a more likely cause of delayed-onset cavitation events.

  10. Dynamical Delays Between Starburst and AGN Activity in Galaxy Nuclei

    CERN Document Server

    Hopkins, Philip F

    2011-01-01

    Observations of AGN have suggested a possible delay between the peak of star formation (on some scale) and AGN activity. Feedback from fast stellar winds has been invoked to explain this, but this is not likely to be viable in bright systems accreting primarily cold dense gas. We show that such a delay can arise even in bright quasars for purely dynamical reasons. If some large-scale process produces rapid inflow, smaller scales will quickly become gas-dominated. As the gas density peaks, so does the SFR. However, gravitational torques which govern further inflow are relatively inefficient in gas-dominated systems; as more gas is turned into stars, the stars provide an efficient angular momentum sink allowing more rapid inflow. Moreover, the gas provided to the central regions in mergers or strong disk instabilities will typically be ~100 times larger than that needed to fuel the BH; the system is effectively in the 'infinite gas supply' limit. BH growth can therefore continue for some time while the gas supp...

  11. Recent advances in organic thermally activated delayed fluorescence materials.

    Science.gov (United States)

    Yang, Zhiyong; Mao, Zhu; Xie, Zongliang; Zhang, Yi; Liu, Siwei; Zhao, Juan; Xu, Jiarui; Chi, Zhenguo; Aldred, Matthew P

    2017-02-06

    Organic materials that exhibit thermally activated delayed fluorescence (TADF) are an attractive class of functional materials that have witnessed a booming development in recent years. Since Adachi et al. reported high-performance TADF-OLED devices in 2012, there have been many reports regarding the design and synthesis of new TADF luminogens, which have various molecular structures and are used for different applications. In this review, we summarize and discuss the latest progress concerning this rapidly developing research field, in which the majority of the reported TADF systems are discussed, along with their derived structure-property relationships, TADF mechanisms and applications. We hope that such a review provides a clear outlook of these novel functional materials for a broad range of scientists within different disciplinary areas and attracts more researchers to devote themselves to this interesting research field.

  12. SUMOylation inhibits FOXM1 activity and delays mitotic transition.

    Science.gov (United States)

    Myatt, S S; Kongsema, M; Man, C W-Y; Kelly, D J; Gomes, A R; Khongkow, P; Karunarathna, U; Zona, S; Langer, J K; Dunsby, C W; Coombes, R C; French, P M; Brosens, J J; Lam, E W-F

    2014-08-21

    The forkhead box transcription factor FOXM1 is an essential effector of G2/M-phase transition, mitosis and the DNA damage response. As such, it is frequently deregulated during tumorigenesis. Here we report that FOXM1 is dynamically modified by SUMO1 but not by SUMO2/3 at multiple sites. We show that FOXM1 SUMOylation is enhanced in MCF-7 breast cancer cells in response to treatment with epirubicin and mitotic inhibitors. Mutation of five consensus conjugation motifs yielded a SUMOylation-deficient mutant FOXM1. Conversely, fusion of the E2 ligase Ubc9 to FOXM1 generated an auto-SUMOylating mutant (FOXM1-Ubc9). Analysis of wild-type FOXM1 and mutants revealed that SUMOylation inhibits FOXM1 activity, promotes translocation to the cytoplasm and enhances APC/Cdh1-mediated ubiquitination and degradation. Further, expression of the SUMOylation-deficient mutant enhanced cell proliferation compared with wild-type FOXM1, whereas the FOXM1-Ubc9 fusion protein resulted in persistent cyclin B1 expression and slowed the time from mitotic entry to exit. In summary, our findings suggest that SUMOylation attenuates FOXM1 activity and causes mitotic delay in cytotoxic drug response.

  13. Effects of 0.5mT power frequency electromagnetic fields on delayed rectifier potassium channels in hippocampus CA3 pyramidal neurons%0.5 mT工频磁场对小鼠海马CA3区锥体神经元延迟整流钾离子通道和动作电位的影响

    Institute of Scientific and Technical Information of China (English)

    沈佩同; 毕平; 李刚; 林凌

    2010-01-01

    Objective To study the effects of 0.5mT power frequency electromagnetic fields on hippocampus CA3 pyramidal neurons. Methods Hippocampus CA3 pyramidal neurons of rats were prepared by acute isolation and then exposed to an electromagnetic fields, with frequency of 50 Hz and the intensity of 0.5 mT,for 30 minutes. The delayed rectifier potassium channel currents were recorded by whole-cell patch-clamp technique. Results The results showed that after 30 minutes exposure to the electromagnetic fields, the delayedrectifier potassium channel current density of the rats' hippocampus CA3 area pyramidal neurons decreased, with the maximum value of control group was(171.05±1.32) pA/pF, and that of the exposure group was(139.65±2.37)pA/pE(n=12, P<0.05). The half-activation potential of control group and that of exposure group were (7.44±0.64)mV and (34.09±6.48) mV(n=12, P<0.05), respectively and the slope factor were 11.36±0.57 and 19.97 ±3.45(n=12, P<0.05), respectively. APD90 extended from (14.63±0.34) ms to (21.74±1.47) ms (n=12, P<0.05). Conclusion It can be speculated that the electromagnetic fields can reduce the currents of delayed rectifier potassium,change the process of activation and increase the half activation potential. After exposure, the activation speed decreased, while the APD increases.%目的 研究与日常生活密切相关的0.5 mT工频磁场对小鼠海马CA3区锥体神经元的影响.方法 采用急性分离的方法制备小鼠海马CA3区锥体神经元,用0.5 mT、50 Hz磁场对小鼠海马CA3区锥体神经元刺激30 min后,运用全细胞膜片钳技术研究其延迟整流钾通道电流,Ik和动作电位特性.结果 0.5 mT工频磁场照射小鼠海马CA3区锥体神经元30 min后,其电流密度减小,对照组和曝磁组最大电流密度分别为(171.05+1.32)pA/pF、(139.65±2.37)pA/pF(n=12,P<0.05);对照组和曝磁组半数激活电压分别为(7.44±0.64)mV、(34.09+6.48)mV(n=12,P<0.05);斜率因子分别为11.36±0.57

  14. Analysis of Single Phase PWM Rectifier for Different Applications

    Science.gov (United States)

    Mitra, Arkendu; Chowdhuri, Sumana

    2016-06-01

    This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.

  15. ACTIVE CONTROL OF A FLEXIBLE CANTILEVER PLATE WITH MULTIPLE TIME DELAYS

    Institute of Scientific and Technical Information of China (English)

    Longxiang Chen; Ji Pan; Guoping Cai

    2008-01-01

    Active control of a flexible cantilever plate with multiple time delays is investigated using the discrete optimal control method.A controller with multiple time delays is presented.In this controller,time delay effect is incorporated in the mathematical model of the dynamic system throughout the control design and no approximations and assumptions are made in the controller derivation,so the system stability is easily guaranteed.Furthermore,this controller is available for both small time delays and large time delays.The feasibility and efficiency of the proposed controller are verified through numerical simulations in the end of this paper.

  16. Effects of piperine on abnormalities of inward rectifier potassium current and ultra rapid delayed rectifier potassium current induced by hydrogen peroxide in rabbit atrial myocytes%胡椒碱减轻H2O2引起的兔心房肌细胞内向整流钾电流及超速激活延迟整流钾电流的异常改变

    Institute of Scientific and Technical Information of China (English)

    刘岩; 李泱; 林琨; 田苗; 王玉堂; 单兆亮

    2012-01-01

    目的:研究胡椒碱对H2O2引起的兔单个心房肌细胞内向整流钾电流(IK1)及超速激活的延迟整流钾电流(IKUr)异常的影响.方法:采用全细胞膜片钳技术分析50 μmol/L H2O2对兔单个心房肌细胞IK1和IKUr的影响,并研究预先应用7 μmol/L胡椒碱对其的保护作用.结果:7 μmol/L胡椒碱对正常兔心房肌细胞IK1和IKUr及其通道动力学无显著影响.在50 μmol/L H2O2作用下,兔心房肌细胞IK1峰值由(-148.2±16.7)pA/pF降低至(-64.2±9.8)pA/pF (P<0.05),电流-电压曲线上移;而IKUr峰值由(16.0±2.1)pA/pF降低至(6.1±1.4)pA/pF (P<0.05),电流-电压曲线下移,通道稳态激活曲线右移,通道稳态失活曲线左移及恢复时间减慢,而且存在频率依赖性特征.预先给予7 μmol/L胡椒碱,明显减轻H2O2对IK1和IKUr的抑制作用(P<0.01),并可减少H2O2对超速激活延迟整流钾通道动力学的异常影响.结论:胡椒碱可减轻氧化应激对心房肌细胞IK1和IKUr的影响.%AIM: To study the proleclive effect of piperine on abnormalilyies of inward rectifier potassium cur-rent ( IK1 ) and ultra rapid delayed rectifier polassium currenl ( IKUT) induced by hydrogen peroxide ( H2 O2 ) in single rabbil alrial myocytes. METHODS: The technique of whole - cell patch - clamp was used Lo study the effecl of H2 O2 at concen-tralion of 50 μmol/L on IK1 and /Kut in single rabbil alrial myocyles. The proleclive effecl of prelrealmenl with piperine (7 μmol/L) was also observed. RESULTS:The piperine al concenlralion of 7 μmol/L had no significant effecl on IK1 and IKUt and their channel dynamics. In the presence of H2O2 at concenlralion of 50 μmol/L, the peak currents of /K1 and /KUT reduced significanlly ( P < 0. 05 ) . The sleady - state aclivalion curve of /Kut was shifted right, the sleady - state inaclivalion curve of IKUt was shifted left, and the recovery from inaclivalion of IKUt was shifted downward. The IKUt showed frequency -dependenl characteristics

  17. RTD application in low power UHF rectifiers

    Science.gov (United States)

    Sinyakin, V. Yu; Makeev, M. O.; Meshkov, S. A.

    2016-08-01

    In the current work, the problem of UHF RFID passive tag sensitivity increase is considered. Tag sensitivity depends on HF signal rectifier efficiency and antenna-rectifier impedance matching. Possibility of RFID passive tag sensitivity increase up to 10 times by means of RTD use in HF signal rectifier in comparison with tags based on Schottky barrier diode is shown.

  18. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    OpenAIRE

    Jianeng Tang

    2014-01-01

    Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  19. Synchronization of Different Fractional Order Time-Delay Chaotic Systems Using Active Control

    Directory of Open Access Journals (Sweden)

    Jianeng Tang

    2014-01-01

    Full Text Available Chaos synchronization of different fractional order time-delay chaotic systems is considered. Based on the Laplace transform theory, the conditions for achieving synchronization of different fractional order time-delay chaotic systems are analyzed by use of active control technique. Then numerical simulations are provided to verify the effectiveness and feasibility of the developed method. At last, effects of the fraction order and the time delay on synchronization are further researched.

  20. Voltage balancing control algorithm for cascaded H-bridge rectifier based on active power feedback%基于功率反馈的H桥级联型整流器电压平衡控制算法

    Institute of Scientific and Technical Information of China (English)

    陶兴华; 李永东; 孙敏

    2011-01-01

    A power-feedback based control algorithm was developed to balance the DC-link voltages in a cascaded H-bridge(CHB) pulse width modulation(PWM) rectifier.The average mathematic model of the CHB rectifier is built.The relationship between the modulation index and the active power of cells is deduced by the mathematic analysis,from which the voltage balancing control method can be derived.Moreover,the feasibility of the proposed method is also discussed.Simulations on a four-cell CHB rectifier and tests on a two-cell prototype indicate that the CHB rectifier can achieve good performance on both DC-link voltage balancing and grid current regulation.%提出了一种基于功率反馈的直流母线电压平衡算法,用于对H桥级联型(cascaded H-bridge,CHB)脉冲宽度调制(PWM)整流器的电压控制。建立了CHB整流器基于平均意义下的数学模型;通过数学分析得到了各级整流器稳态工作时有功功率与调制比之间的关系,依此推出基于功率反馈的电压平衡控制算法,并对该算法的适用条件进行讨论;在MATLAB上进行了4级级联的系统仿真,搭建2级级联的实验样机进行实验研究。仿真与实验结果表明:该算法在满足适用范围的前提条件下,能够实现对多级CHB整流器直流母线电压的平衡控制,

  1. Mitotic activity and delay in fixation of tumour tissue. The influence of delay in fixation on mitotic activity of a human osteogenic sarcoma grown in athymic nude mice.

    Science.gov (United States)

    Graem, N; Helweg-Larsen, K

    1979-09-01

    The purpose of the present investigation was to study the effect of delay in fixation on the mitotic activity in tumour tissue. A human osteogenic sarcoma, especially suitable for counting of mitoses, grown in athymic nude mice, was fixed with varying delay and the mitotic, prophase, metaphase and ana-telophase indices were determined. An almost exponential decline of the mitotic index was observed with a reduction to 49.4% and 15.0% after respectively 60 and 180 minutes. The proportional incidence of prophases, metaphases and ana-telophases changed so that a relative accummulation of advanced phases occured during the 180 minutes of observation. It is concluded that delay in fixation of a magnitude, which is not uncommon in routine surgical pathology, may allow the majority of mitoses to terminate, resulting in unreliable assessments of mitotic activity.

  2. Highly Efficient, Simplified, Solution-Processed Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diodes.

    Science.gov (United States)

    Kim, Young-Hoon; Wolf, Christoph; Cho, Himchan; Jeong, Su-Hun; Lee, Tae-Woo

    2016-01-27

    Highly efficient, simplified, solution-processed thermally activated delayed-fluorescence organic light-emitting diodes can be realized by using pure-organic thermally activated delayed fluorescence emitters and a multifunctional buffer hole-injection layer, in which high EQE (≈24%) and current efficiency (≈73 cd A(-1) ) are demonstrated. High-efficiency fluorescence red-emitting and blue-emitting devices can also be fabricated in this manner.

  3. Influence analysis of time delay to active mass damper control system using pole assignment method

    Science.gov (United States)

    Teng, J.; Xing, H. B.; Lu, W.; Li, Z. H.; Chen, C. J.

    2016-12-01

    To reduce the influence of time delay on the Active Mass Damper (AMD) control systems, influence analysis of time delay on system poles and stability is applied in the paper. A formula of the maximum time delay for ensuring system stability is established, by which the influence analysis of control gains on system stability is further arisen. In addition, the compensation controller is designed based on the given analysis results and pole assignment. A numerical example and an experiment are illustrated to verify that the performance of time-delay system. The result is consistent to that of the long-time delay control system, as well as to proof the better effectiveness of the new method proposed in this article.

  4. New exponential synchronization criteria for time-varying delayed neural networks with discontinuous activations.

    Science.gov (United States)

    Cai, Zuowei; Huang, Lihong; Zhang, Lingling

    2015-05-01

    This paper investigates the problem of exponential synchronization of time-varying delayed neural networks with discontinuous neuron activations. Under the extended Filippov differential inclusion framework, by designing discontinuous state-feedback controller and using some analytic techniques, new testable algebraic criteria are obtained to realize two different kinds of global exponential synchronization of the drive-response system. Moreover, we give the estimated rate of exponential synchronization which depends on the delays and system parameters. The obtained results extend some previous works on synchronization of delayed neural networks not only with continuous activations but also with discontinuous activations. Finally, numerical examples are provided to show the correctness of our analysis via computer simulations. Our method and theoretical results have a leading significance in the design of synchronized neural network circuits involving discontinuous factors and time-varying delays.

  5. Activation of dorsal raphe serotonin neurons is necessary for waiting for delayed rewards.

    Science.gov (United States)

    Miyazaki, Kayoko W; Miyazaki, Katsuhiko; Doya, Kenji

    2012-08-01

    The forebrain serotonergic system is a crucial component in the control of impulsive behaviors. We previously reported that the activity of serotonin neurons in the midbrain dorsal raphe nucleus increased when rats performed a task that required them to wait for delayed rewards. However, the causal relationship between serotonin neural activity and the tolerance for the delayed reward remained unclear. Here, we test whether the inhibition of serotonin neural activity by the local application of the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin in the dorsal raphe nucleus impairs rats' tolerance for delayed rewards. Rats performed a sequential food-water navigation task that required them to visit food and water sites alternately via a tone site to get rewards at both sites after delays. During the short (2 s) delayed reward condition, the inhibition of serotonin neural activity did not significantly influence the numbers of reward choice errors (nosepoke at an incorrect reward site following a conditioned reinforcer tone), reward wait errors (failure to wait for the delayed rewards), or total trials (sum of reward choice errors, reward wait errors, and acquired rewards). By contrast, during the long (7-11 s) delayed reward condition, the number of wait errors significantly increased while the numbers of total trials and choice errors did not significantly change. These results indicate that the activation of dorsal raphe serotonin neurons is necessary for waiting for long delayed rewards and suggest that elevated serotonin activity facilitates waiting behavior when there is the prospect of forthcoming rewards.

  6. Acute physical activity and delayed attention in primary school students.

    Science.gov (United States)

    Gallotta, M C; Emerenziani, G P; Franciosi, E; Meucci, M; Guidetti, L; Baldari, C

    2015-06-01

    To examine the influence of different types of exertion on immediate and delayed attention in 116 primary school children divided in three groups of exertion [cognitive exertion - CE (school curricular lesson), physical exertion - PE (traditional physical education lesson), mixed cognitive and physical exertion - CPE (coordinative physical education lesson)]. CPE was the combination of physical load due to the practice of physical exercises and of cognitive load requested to perform movement-based problem solving tasks requiring accurate timing, temporal estimations, temporal production, and spatial adjustments. Children's attentional capacity was tested before (pre) and after (at 0 min and at 50 min post) a CE, a PE, or a CPE lesson, using the d2-test of attention, and analyzed using a 3 × 3 × 2 mixed analysis of covariance with exertion type and time as within factors, gender as between factor, and baseline data as covariate. Effect sizes were calculated as partial eta squared (ƞ(2)). Results showed that participants' attentional performance was significantly affected by exertion type (P < 0.0001), by time (P < 0.0001) and by exertion type × time interactions (P < 0.0001). The effect sizes ranged from medium (0.039) to large (0.437). Varying the type of exertion has different beneficial influences on the level of attention in school children.

  7. Nonlinear Dynamical Analysis on Four Semi-Active Dynamic Vibration Absorbers with Time Delay

    Directory of Open Access Journals (Sweden)

    Yongjun Shen

    2013-01-01

    Full Text Available In this paper four semi-active dynamic vibration absorbers (DVAs are analytically studied, where the time delay induced by measurement and execution in control procedure is included in the system. The first-order approximate analytical solutions of the four semi-active DVAs are established by the averaging method, based on the illustrated phase difference of the motion parameters. The comparisons between the analytical and the numerical solutions are carried out, which verify the correctness and satisfactory precision of the approximate analytical solutions. Then the effects of the time delay on the dynamical responses are analyzed, and it is found that the stability conditions for the steady-state responses of the primary systems are all periodic functions of time delay, with the same period as the excitation one. At last the effects of time delay on control performance are discussed.

  8. Long QT 1 mutation KCNQ1A344V increases local anesthetic sensitivity of the slowly activating delayed rectifier potassium current

    DEFF Research Database (Denmark)

    Siebrands, Cornelia C; Binder, Stephan; Eckhoff, Ulrike;

    2006-01-01

    BACKGROUND: Anesthesia in patients with long QT syndrome (LQTS) is a matter of concern. Congenital LQTS is most frequently caused by mutations in KCNQ1 (Kv7.1), whereas drug-induced LQTS is a consequence of HERG (human ether-a-go-go-related gene) channel inhibition. The aim of this study was to i...

  9. Hippocampal and Cerebellar Single-Unit Activity During Delay and Trace Eyeblink Conditioning in the Rat

    Science.gov (United States)

    Green, John T.; Arenos, Jeremy D.

    2007-01-01

    In delay eyeblink conditioning, the CS overlaps with the US and only a brainstem-cerebellar circuit is necessary for learning. In trace eyeblink conditioning, the CS ends before the US is delivered and several forebrain structures, including the hippocampus, are required for learning, in addition to a brainstem-cerebellar circuit. The interstimulus interval (ISI) between CS onset and US onset is perhaps the most important factor in classical conditioning, but studies comparing delay and trace conditioning have typically not matched these procedures in this crucial factor, so it is often difficult to determine whether results are due to differences between delay and trace or to differences in ISI. In the current study, we employed a 580-ms CS-US interval for both delay and trace conditioning and compared hippocampal CA1 activity and cerebellar interpositus nucleus activity in order to determine whether a unique signature of trace conditioning exists in patterns of single-unit activity in either structure. Long-Evans rats were chronically implanted in either CA1 or interpositus with microwire electrodes and underwent either delay eyeblink conditioning, or trace eyeblink conditioning with a 300-ms trace period between CS offset and US onset. On trials with a CR in delay conditioning, CA1 pyramidal cells showed increases in activation (relative to a pre-CS baseline) during the CS-US period in sessions 1-4 that was attenuated by sessions 5-6. In contrast, on trials with a CR in trace conditioning, CA1 pyramidal cells did not show increases in activation during the CS-US period until sessions 5-6. In sessions 5-6, increases in activation were present only to the CS and not during the trace period. For rats with interpositus electrodes, activation of interpositus neurons on CR trials was present in all sessions in both delay and trace conditioning. However, activation was greater in trace compared to delay conditioning in the first half of the CS-US interval (during the

  10. High order single step time delay compensation algorithm for structural active control

    Institute of Scientific and Technical Information of China (English)

    王焕定; 耿淑伟; 王伟

    2002-01-01

    The optimal instantaneous high order single step algorithm for active control is first discussed andthen, the n + 1 time step controlling force vector of the instantaneous optimal algorithm is derived from way of ntime state vector. An estimating algorithm, is developed from this to solve the problem of active control withtime delay compensation. The estimating algorithm based on this high order single step β method (HSM) foun-dation, is proven by simulation and experiment analysis, to be a valid solution to problem of active control withtime delay compensation.

  11. Linear and nonlinear analyses of multi-channel mechanomyographic recordings reveal heterogeneous activation of wrist extensors in presence of delayed onset muscle soreness.

    Science.gov (United States)

    Madeleine, Pascal; Hansen, Ernst A; Samani, Afshin

    2014-12-01

    In this study, we applied multi-channel mechanomyographic (MMG) recordings in combination with linear and nonlinear analyses to investigate muscular and musculotendinous effects of high intensity eccentric exercise. Twelve accelerometers arranged in a 3 × 4 matrix over the dominant elbow muscles were used to detect MMG activity in 12 healthy participants. Delayed onset muscle soreness was induced by repetitive high intensity eccentric contractions of the wrist extensor muscles. Average rectified values (ARV) as well as percentage of recurrence (%REC) and percentage of determinism (%DET) extracted from recurrence quantification analysis were computed from data obtained during static-dynamic contractions performed before exercise, immediately after exercise, and in presence of muscle soreness. A linear mixed model was used for the statistical analysis. The ARV, %REC, and %DET maps revealed heterogeneous MMG activity over the wrist extensor muscles before, immediately after, and in presence of muscle soreness (P<0.01). The ARVs were higher while the %REC and %DET were lower in presence of muscle soreness compared with before exercise (P<0.05). The study provides new key information on linear and nonlinear analyses of multi-channel MMG recordings of the wrist extensor muscles following eccentric exercise that results in muscle soreness. Recurrence quantification analysis can be suggested as a tool for detection of MMG changes in presence of muscle soreness.

  12. Alkylresorcinols activate SIRT1 and delay ageing in Drosophila melanogaster

    Science.gov (United States)

    Kayashima, Yasunari; Katayanagi, Yuki; Tanaka, Keiko; Fukutomi, Ryuta; Hiramoto, Shigeru; Imai, Shinjiro

    2017-01-01

    Sirtuins are enzymes that catalyze NAD+ dependent protein deacetylation. The natural polyphenolic compound resveratrol received renewed interest when recent findings implicated resveratrol as a potent SIRT1 activator capable of mimicking the effects of calorie restriction. However, resveratrol directly interacts with fluorophore-containing peptide substrates. It was demonstrated that the SIRT1 activation of resveratrol is affected by the amino acid composition of the substrate. Resveratrol did increase the enzyme activity in cases in which hydrophobic amino acids are at the +1 position to the acetylated lysine in the substrate. Alkylresorcinols (ARs) are compounds that belong to the family of phenolic lipids, and they are found in numerous biological species. Here we show that the natural activators ARs increased the Vmax of recombinant SIRT1 for NAD+ and peptide substrate, and that ARs decreased acetylated histone in human monocyte cells by stimulating SIRT1-dependent deacetylation of substrates. ARs also extended the lifespan of Drosophila melanogaster, which was shown to be dependent on functional Sir2. Our results demonstrated that ARs are natural catalytic activators for sirtuin. PMID:28252007

  13. 银杏苦内酯B对缺血豚鼠心室肌动作电位、L-型钙电流和延迟整流钾电流的作用%THE EFFECT OF GINKGOLIDE B ON ACTION POTENTIAL,L-TYPE CALCIUM CURRENT AND DELAYED RECTIFIER POTASSIUM CURRENT IN ISCHEMIC GUINEA PIG VENTRICULAR MYOCYTES

    Institute of Scientific and Technical Information of China (English)

    祁小燕; 张志雄; 崔启启; 施渭彬; 徐有秋

    2004-01-01

    目的:研究银杏苦内酯B对正常和缺血心室肌细胞动作电位(action potential,AP),L-型钙电流(L-type calcium current,ICa-L)、延迟整流钾电流(Delayed Rectifier Currennt,IK)的影响.方法:用常规细胞内微电极方法记录豚鼠心室肌细胞动作电位,用全细胞膜片钳技术记录游离心室肌细胞离子流.结果:①在生理条件下,银杏苦内酯B可缩短心室肌细胞动作电位时程 (action potential duration,APD),但对AP其他参数无影响,银杏苦内酯B可增大IK,呈浓度依赖性,但对ICa-L无显著作用;②在缺血条件下,APD50、APD90明显缩短,RP、APA减小,Vmax减慢,而银杏苦内酯B则可延缓和减轻缺血所引起上述参数的变化;3.在缺血条件下,IK和ICa-L均受到抑制,但加入银杏苦内酯B后可逆转缺血所造成这两种离子流的减小.结论:银杏苦内酯B可对抗心肌缺血所引起的心肌电生理的变化,提示银杏苦内酯B可预防心律失常的发生.

  14. Projective Synchronization in Modulated Time-Delayed Chaotic Systems Using an Active Control Approach

    Institute of Scientific and Technical Information of China (English)

    冯存芳; 汪映海

    2011-01-01

    Projective synchronization in modulated time-delayed systems is studied by applying an active control method. Based on the Lyapunov asymptotical stability theorem, the controller and sufficient condition for projective synchronization are calculated analytically. We give a genera./ method with which we can achieve projective synchronization in modulated time-delayed chaotic systems. This method allows us to adjust the desired scaling factor arbitrarily. The effectiveness of our method is confirmed by using the famous delay-differential equations related to optical bistable or hybrid optical bistable devices. Numerical simulations fully support the analytical approach.%Projective synchronization in modulated time-delayed systems is studied by applying an active control method.Based on the Lyapunov asymptotical stability theorem,the controller and sufficient condition for projective synchronization are calculated analytically.We give a general method with which we can achieve projective synchronization in modulated time-delayed chaotic systems.This method allows us to adjust the desired scaling factor arbitrarily.The effectiveness of our method is confirmed by using the famous delay-differential equations related to optical bistable or hybrid optical bistable devices.Numerical simulations fully support the analytical approach.

  15. Active vibration control for nonlinear vehicle suspension with actuator delay via I/O feedback linearization

    Science.gov (United States)

    Lei, Jing; Jiang, Zuo; Li, Ya-Li; Li, Wu-Xin

    2014-10-01

    The problem of nonlinear vibration control for active vehicle suspension systems with actuator delay is considered. Through feedback linearization, the open-loop nonlinearity is eliminated by the feedback nonlinear term. Based on the finite spectrum assignment, the quarter-car suspension system with actuator delay is converted into an equivalent delay-free one. The nonlinear control includes a linear feedback term, a feedforward compensator, and a control memory term, which can be derived from a Riccati equation and a Sylvester equation, so that the effects produced by the road disturbances and the actuator delay are compensated, respectively. A predictor is designed to implement the predictive state in the designed control. Moreover, a reduced-order observer is constructed to solve its physical unrealisability problem. The stability proofs for the zero dynamics and the closed-loop system are provided. Numerical simulations illustrate the effectiveness and the simplicity of the designed control.

  16. Fully controlled 5-phase, 10-pulse, line commutated rectifier

    Directory of Open Access Journals (Sweden)

    Mahmoud I. Masoud

    2015-12-01

    Full Text Available The development and production of multiphase machines either generators or motors, specially five-phase, offers improved performance compared to three-phase counterpart. Five phase generators could generate power in applications such as, but not limited to, wind power generation, electric vehicles, aerospace, and oil and gas. The five-phase generator output requires converter system such as ac–dc converters. In this paper, a fully controlled 10-pulse line commutated rectifier, suitable to be engaged with wind energy applications, fed from five-phase source is introduced. A shunt active power filter (APF is used to improve power factor and supply current total harmonic distortion (THD. Compared to three-phase converters, 6-pulse or 12-pulse rectifiers, the 10-pulse rectifier engaged with 5-phase source alleviate their drawbacks such as high dc ripples and no need for electric gear or phase shifting transformer. MATLAB/SIMULINK platform is used as a simulation tool to investigate the performance of the proposed rectifier.

  17. A case of delayed cardiac perforation of active ventricular lead

    Directory of Open Access Journals (Sweden)

    Hangyuan Guo

    2011-12-01

    Full Text Available A 65-year-old man was admitted as for one month of repetitive dizziness and one episode of syncope. Electrocardiogram showed sinus bradycardia and his Holter monitoring also showed sinus bradycardia with sinus arrest, sino-atrial block and a longest pause of 4.3 s. Then sick sinus syndrome and Adam-Stokes syndrome were diagnosed. Then a dual chamber pacemaker (Medtronic SDR303 was implanted and the parameters were normal by detection. The patient was discharged 1 week later with suture removed. Then 1.5 month late the patient was presented to hospital once again for sudden onset of chest pain with exacerbation after taking deep breath. Pacemaker programming showed both pacing and sensing abnormality with threshold of?5.0V and resistance of 1200?. Lead perforation was revealed by chest X-ray and confirmed by echocardiogram. Considering the fact that there was high risk to remove ventricular lead, spiral tip of previous ventricular lead was withdrew followed by implantation of a new ventricular active lead to the septum. Previous ventricular lead was maintained. As we know that the complications of lead perforation in the clinic was rare. Here we discuss the clinical management and the possible reasons for cardiac perforation of active ventricular lead.

  18. Decreased frontal, striatal and cerebellar activation in adults with ADHD during an adaptive delay discounting task.

    Science.gov (United States)

    Ortiz, Nick; Parsons, Aisling; Whelan, Robert; Brennan, Katie; Agan, Maria L F; O'Connell, Redmond; Bramham, Jessica; Garavan, Hugh

    2015-01-01

    An important characteristic of childhood attention-deficit/hyperactivity disorder (ADHD) is a bias towards small immediate versus larger delayed rewards, but it is not known if this symptom is also a feature of adult ADHD. A delay-discounting task was administered to participants with adult ADHD and a comparison group in conjunction with functional magnetic resonance imaging. Participants responded to a series of questions that required judgments between small sums of money available immediately and larger sums obtained after a temporal delay. Question parameters were adjusted by an adaptive algorithm designed to converge on each participant's discounting indifference point, an individual set point at which there is equal valuation of both choices. In all participants, robust task activation was observed in regions previously identified in functional imaging studies of delay discounting. However, adults with ADHD showed less task activation in a number of regions including the dorsolateral prefrontal cortex, superior frontal gyrus, anterior cingulate, caudate nucleus and declive of the cerebellum. Additionally, the degree to which a participant discounted delayed rewards was inversely related to task activation in the cerebellum. The results suggest that the bias towards immediate rewards in childhood ADHD may not persist behaviorally, but instead present in adulthood as alterations in frontostriatal and frontocerebellar networks.

  19. Effect of Magnetic Activity on Ionospheric Time Delay at Low Latitude

    Indian Academy of Sciences (India)

    Soumi Bhattacharya; Smita Dubey; Rajesh Tiwari; P. K. Purohit; A. K. Gwal

    2008-03-01

    The purpose of this work is to investigate the effect of magnetic activity on ionospheric time delay at low latitude Station Bhopal (geom. lat. 23.2°N, geom. long. 77.6°E) using dual frequency (1575.42 and 1227.60 MHz) GPS measurements. Data from GSV4004A GPS Ionospheric Scintillation and TEC monitor (GISTM) have been chosen to study these effects. This paper presents the results of ionospheric time delay during quiet and disturbed days for the year 2005. Results show that maximum delay is observed during quiet days in equinoxial month while the delays of disturbed period are observed during the months of winter. We also study the ionospheric time delay during magnetic storm conditions for the same period. Results do not show any clear relationship either with the magnitude of the geomagnetic storm or with the main phase onset (MPO) of the storm. But most of the maximum ionospheric time delay variations are observed before the main phase onset (MPO) or sudden storm commencement (SSC) as compared to storm days.

  20. Detection of active bile leak with Gd-EOB-DTPA enhanced MR cholangiography: Comparison of 20–25 min delayed and 60–180 min delayed images

    Energy Technology Data Exchange (ETDEWEB)

    Cieszanowski, Andrzej, E-mail: andrzej.cieszanowski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Stadnik, Anna, E-mail: aniaws@yahoo.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Lezak, Aleksandra, E-mail: aleksandralezak@gmail.com [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Maj, Edyta, E-mail: em26@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Zieniewicz, Krzysztof, E-mail: krzysztof.zieniewicz@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowinska-Berman, Katarzyna, E-mail: kasiarowinska@wp.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Grudzinski, Ireneusz P., E-mail: ireneusz.grudzinski@wum.edu.pl [Department of Toxicology, Medical University of Warsaw, Faculty of Pharmacy, ul. Banacha 1, 02-097 Warsaw (Poland); Krawczyk, Marek, E-mail: marek.krawczyk@wum.edu.pl [Chair and Department of General, Transplant and Liver Surgery, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland); Rowiński, Olgierd, E-mail: olgierd.rowinski@wum.edu.pl [2nd Department of Clinical Radiology, Medical University of Warsaw, ul. Banacha 1A, 02-097 Warszawa (Poland)

    2013-12-01

    Objectives: The purpose of this study was to assess the value of contrast-enhanced magnetic resonance cholangiography (MRC) performed in different time delays after injection of gadoxetic acid disodium (Gd-EOB-DTPA) for the diagnosis of active bile leak. Methods: This retrospective analysis included Gd-EOB-DTPA enhanced MR images of 34 patients suspected of bile leak. Images were acquired 20–25 min after Gd-EOB-DTPA injection. If there was inadequate contrast in the bile ducts then delayed images after 60–90 min and 150–180 min were obtained. Results were correlated with intraoperative findings, ERCP results, clinical data, laboratory tests, and follow-up examinations. Results: Gd-EOB-DTPA enhanced MRC yielded an overall sensitivity of 96.4%, specificity of 100% and accuracy of 97.1% for the diagnosis of an active bile leak. The sensitivity of 20–25 min delayed MR images was 42.9%, of combined 20–25 min and 60–90 min delayed images was 92.9% and of combined 20–25 min, 60–90 min and 150–180 min delayed images was 96.4%. Conclusions: Gd-EOB-DTPA enhanced MRC utilizing delayed phase images was effective for detecting the presence and location of active bile leaks. The images acquired 60–180 min post-injection enabled identification of bile leaks even in patients with a dilated biliary system or moderate liver dysfunction.

  1. Discovery, characterization and structure-activity relationships of an inhibitor of inward rectifier potassium (Kir channels with preference for Kir2.3, Kir3.X and Kir7.1

    Directory of Open Access Journals (Sweden)

    Jerod S Denton

    2011-11-01

    Full Text Available The inward rectifier family of potassium (Kir channels is comprised of at least 16 family members exhibiting broad and often overlapping cellular, tissue or organ distributions. The discovery of disease-causing mutations in humans and experiments on knockout mice has underscored the importance of Kir channels in physiology and in some cases raised questions about their potential as drug targets. However, the paucity of potent and selective small-molecule modulators targeting specific family members has with few exceptions mired efforts to understand their physiology and assess their therapeutic potential. A growing body of evidence suggests that GIRK (G protein-regulated inward rectifier K channels of the Kir3.X subfamily may represent novel targets for the treatment of atrial fibrillation. In an effort to expand the molecular pharmacology of GIRK, we performed a thallium (Tl+ flux-based high-throughput screen (HTS of a Kir1.1 inhibitor library for modulators of GIRK. One compound, termed VU573, exhibited 10-fold selectivity for GIRK over Kir1.1 (IC50 = 1.9 M and 19 M, respectively and was therefore selected for further study. In electrophysiological experiments performed on Xenopus laevis oocytes and mammalian cells, VU573 inhibited Kir3.1/3.2 (neuronal GIRK and Kir3.1/3.4 (cardiac GIRK channels with equal potency and preferentially inhibited GIRK, Kir2.3 and Kir7.1 over Kir1.1 and Kir2.1. Tl+ flux assays were established for Kir2.3 and the M125R pore mutant of Kir7.1 to support medicinal chemistry efforts to develop more potent and selective analogs for these channels. The structure-activity relationships of VU573 revealed few analogs with improved potency, however two compounds retained most of their activity toward GIRK and Kir2.3 and lost activity toward Kir7.1. We anticipate that the VU573 series will be useful for exploring the physiology and structure-function relationships of these Kir channels.

  2. Current and Voltage Conveyors in Current- and Voltage-Mode Precision Full-Wave Rectifiers

    Directory of Open Access Journals (Sweden)

    J. Koton

    2011-04-01

    Full Text Available In this paper new versatile precision full-wave rectifiers using current and/or voltage conveyors as active elements and two diodes are presented. The performance of these circuit solutions is analysed and compared to the opamp based precision rectifier. To analyze the behavior of the functional blocks, the frequency dependent RMS error and DC transient value are evaluated for different values of input voltage amplitudes. Furthermore, experimental results are given that show the feasibilities of the conveyor based rectifiers superior to the corresponding operational amplifier based topology.

  3. Nucleolar re-activation is delayed in mouse embryos cloned from two different cell lines

    DEFF Research Database (Denmark)

    Svarcova, Olga; Dinnyes, A.; Polgar, Z.

    2009-01-01

    displayed early NPBs transformation. In conclusion, despite normal onset of EGA in cloned embryos, activation of functional nucleoli was one cell cycle delayed in NT embryos. NT-MEF embryos displayed normal targeting but delayed activation of nucleolar proteins. Contrary, in NT-HM1 embryos, both......Aim of this study was to evaluate and compare embryonic genome activation (EGA) in mouse embryos of different origin using nucleolus as a marker. Early and late 2-cell and late 4-cell stage embryos, prepared by in vitro fertilization (IVF), parthenogenetic activation (PG), and nuclear transfer...... ofmouse embryonic fibroblast (MEF) and mouse HM1 emryonic stem cells (HM1), were processed for autoradiography following 3H-uridine incubation (transcriptional activity), transmission electron microscopy (ultrastructure) and immunofluorescence (nucleolar proteins; upstream binding factor, UBF...

  4. Role of tissue plasminogen activator/plasmin cascade in delayed neuronal death after transient forebrain ischemia.

    Science.gov (United States)

    Takahashi, Hiroshi; Nagai, Nobuo; Urano, Tetsumei

    We studied the possible involvement of the tissue plasminogen activator (t-PA)/plasmin system on both delayed neuronal death in the hippocampus and the associated enhancement of locomotor activity in rats, after transient forebrain ischemia induced by a four-vessel occlusion (FVO). Seven days after FVO, locomotor activity was abnormally increased and, after 10 days, pyramidal cells were degraded in the CA1 region of the hippocampus. FVO increased the t-PA antigen level and its activity in the hippocampus, which peaked at 4 h. Both the enhanced locomotor activity and the degradation of pyramidal cells were significantly suppressed by intracerebroventricular injection of aprotinin, a plasmin inhibitor, at 4 h but not during FVO. These results suggest the importance of the t-PA/plasmin cascade during the early pathological stages of delayed neuronal death in the hippocampus following transient forebrain ischemia.

  5. Silencing of Doublecortin-Like (DCL) Results in Decreased Mitochondrial Activity and Delayed Neuroblastoma Tumor Growth

    NARCIS (Netherlands)

    C.S. Verissimo; R. Elands; S. Cheng; D.J. Saaltink; J.P. ter Horst; M.N. Alme; C. Pont; B. van de Water; B. Håvik; C.P. Fitzsimons; E. Vreugdenhil

    2013-01-01

    Doublecortin-like (DCL) is a microtubule-binding protein crucial for neuroblastoma (NB) cell proliferation. We have investigated whether the anti-proliferative effect of DCL knockdown is linked to reduced mitochondrial activity. We found a delay in tumor development after DCL knockdown in vivo in do

  6. Sudden death in noncoronary heart disease is associated with delayed paced ventricular activation

    NARCIS (Netherlands)

    Saumarez, RC; Chojnowska, L; Derksen, R; Pytkowski, M; Sterlinski, M; Huang, CLH; Sadoul, N; Hauer, RNW; Ruzyllo, W; Grace, AA

    2003-01-01

    Background-Slowed or delayed myocardial activation and dispersed refractoriness predispose to reentrant excitation that may lead to ventricular fibrillation (VF). Increased ventricular electrogram duration (DeltaED) in response to extrastimuli and increased S1S2 coupling intervals at which electrogr

  7. 急性激活α1和β1肾上腺素能受体对豚鼠心室肌细胞快激活延迟整流钾电流的交叉影响%Cross effects of acute adrenergic stimulation on rapid component of delayed rectifier potassium channel current in guinea-pig left ventricular myocytes

    Institute of Scientific and Technical Information of China (English)

    吴婷婷; 王森; 邹建刚; 曹克将; 许迪

    2014-01-01

    different subtype and both of adrenergic receptors (α1-AR or β1-AR) on the rapidly activating delayed rectifier potassium current ( IKr ) in guinea-pig ventricular myocytes,and the effects of acute stimulation of both α1-AR and β1-AR on IKr current. Methods Single ventricular myocyte was obtained from guinea-pig using enzymatic dissociation technique. Whole-cell patch clamp technique was used to record IKr current. The amplitudes of IKr current before and after stimulation of adrenergic receptors were measured to reflect the effects of acute stimulation of different adrener-gic receptors. The expression level of IKr channel protein after acute stimulation of different subtype of adrenergic receptors was detected by western-blot. Results Phenylephrine( PE) and xamoterol( Xamo) inhibited IKr cur-rent amplitude by a content dependent way,the IC50 was 0. 93 μmol/L and 6. 40 μmol/L respectively. In our study,1 μmol/L PE (PE group) reduced IKr current to 0. 79±0. 02,and shifted the voltage-dependent activa-ting curve to the negative voltage,where U0.5 changed from (-2. 99±1. 44) mV to (-9. 10±1. 74) mV,and k changed a little. 10μmol/L Xamo (Xamo group) reduced IKr current to 0. 72±0. 01,and shifted the voltage-de-pendent activating curve to the negative voltage, where U0. 5 changed from (-4. 54 ± 1. 48 ) mV to (-7. 24 ± 1. 93) mV,and k changed a little. While simultaneously administration of 1 μmol/L PE and 10 μmol/L Xamo (PE+Xamo group) only reduced IKr current to 0. 69±0. 02,and it also shifted the voltage-dependent activating curve to the negative voltage,where U0.5 changed from (-2. 71±1. 95) mV to (-8. 45±1. 97) mV,and k changed a little. In PE group, Xamo group and PE+XAMO group, IKr tail current amplitude decreased by (20. 73±2. 46)%,(27. 99±0. 68)% and (30. 56±1. 80)%,separately. By western-blot,the expression level of IKr channel protein after acute adrenergic stimulation did not show a statistical change. Conclusions Acute stimulation of α1-AR or

  8. Global robust dissipativity of interval recurrent neural networks with time-varying delay and discontinuous activations.

    Science.gov (United States)

    Duan, Lian; Huang, Lihong; Guo, Zhenyuan

    2016-07-01

    In this paper, the problems of robust dissipativity and robust exponential dissipativity are discussed for a class of recurrent neural networks with time-varying delay and discontinuous activations. We extend an invariance principle for the study of the dissipativity problem of delay systems to the discontinuous case. Based on the developed theory, some novel criteria for checking the global robust dissipativity and global robust exponential dissipativity of the addressed neural network model are established by constructing appropriate Lyapunov functionals and employing the theory of Filippov systems and matrix inequality techniques. The effectiveness of the theoretical results is shown by two examples with numerical simulations.

  9. Global robust dissipativity of interval recurrent neural networks with time-varying delay and discontinuous activations

    Science.gov (United States)

    Duan, Lian; Huang, Lihong; Guo, Zhenyuan

    2016-07-01

    In this paper, the problems of robust dissipativity and robust exponential dissipativity are discussed for a class of recurrent neural networks with time-varying delay and discontinuous activations. We extend an invariance principle for the study of the dissipativity problem of delay systems to the discontinuous case. Based on the developed theory, some novel criteria for checking the global robust dissipativity and global robust exponential dissipativity of the addressed neural network model are established by constructing appropriate Lyapunov functionals and employing the theory of Filippov systems and matrix inequality techniques. The effectiveness of the theoretical results is shown by two examples with numerical simulations.

  10. Multi-objective optimal design of active vibration absorber with delayed feedback

    Science.gov (United States)

    Huan, Rong-Hua; Chen, Long-Xiang; Sun, Jian-Qiao

    2015-03-01

    In this paper, a multi-objective optimal design of delayed feedback control of an actively tuned vibration absorber for a stochastically excited linear structure is investigated. The simple cell mapping (SCM) method is used to obtain solutions of the multi-objective optimization problem (MOP). The continuous time approximation (CTA) method is applied to analyze the delayed system. Stability is imposed as a constraint for MOP. Three conflicting objective functions including the peak frequency response, vibration energy of primary structure and control effort are considered. The Pareto set and Pareto front for the optimal feedback control design are presented for two examples. Numerical results have found that the Pareto optimal solutions provide effective delayed feedback control design.

  11. Dynamic behavior of time-delayed acceleration feedback controller for active vibration control of flexible structures

    Science.gov (United States)

    An, Fang; Chen, Wei-dong; Shao, Min-qiang

    2014-09-01

    This paper addresses the design problem of the controller with time-delayed acceleration feedback. On the basis of the reduction method and output state-derivative feedback, a time-delayed acceleration feedback controller is proposed. Stability boundaries of the closed-loop system are determined by using Hurwitz stability criteria. Due to the introduction of time delay into the controller with acceleration feedback, the proposed controller has the feature of not only changing the mass property but also altering the damping property of the controlled system in the sense of equivalent structural modification. With this feature, the closed-loop system has a greater logarithmic decrement than the uncontrolled one, and in turn, the control behavior can be improved. In this connection, the time delay in the acceleration feedback control is a positive factor when satisfying some given conditions and it could be actively utilized. On the ground of the analysis, the developed controller is implemented on a cantilever beam for different controller gain-delay combinations, and the control performance is evaluated with the comparison to that of pure acceleration feedback controller. Simulation and experimental results verify the ability of the controller to attenuate the vibration resulting from the dominant mode.

  12. The influence of fixation delay on mitotic activity and flow cytometric cell cycle variables.

    Science.gov (United States)

    Bergers, E; Jannink, I; van Diest, P I; Cuesta, M A; Meyer, S; van Mourik, J C; Baak, J P

    1997-01-01

    Proliferation variables such as mitotic activity and the percentage of S-phase cells have been shown to be of prognostic value in many tumors, especially in breast cancer. However, some studies reported a decrease in mitotic activity caused by delay in fixation of the tissue. In contrast, other studies showed that the identifiability of mitotic figures decreases after fixation delay, but the total number of mitotic figures and also the percentage of S-phase cells remain unchanged. Most studies have been done on small numbers of experimental tumors, thus introducing the risk of selection bias. The aim of this study was to reinvestigate the influence of fixation delay on mitotic activity and cell cycle variables assessed by flow cytometry in an adequate number of resected human tissues to reach firmer conclusions. Resection specimens of 19 and 21 cases, respectively, for the mitotic activity estimate and the flow cytometric percentage of S-phase calculation were collected directly from the operating theater using lung, breast, and intestinal cancers and normal intestinal mucosa. The tissues were cut in pieces, and from each specimen, pieces were fixed in 4% buffered formaldehyde (for mitosis counting) as well as snap frozen (for flow cytometry) immediately after excision, as well as after a fixation delay of 1, 2, 4, 6, 8, 18, and 24 hours. Moreover, during the fixation delay, one series from each specimen was kept in the refrigerator and the second at room temperature. Thus, a total of 304 (19 X 16) and 336 (21 X 16) specimens were investigated for the mitotic activity estimate and the percentage of S-phase cells calculation, respectively. With regard to the estimation of the mitotic activity, both clear and doubtful mitotic figures were registered separately, obtaining an "uncorrected" and "corrected" (for doubtful mitotic figures) mitotic activity estimate. The percentage of S-phase cells was obtained by cell cycle analysis of flow cytometric DNA-histograms. The

  13. Delaying or advancing higher-order sideband signals with active optomechanics

    CERN Document Server

    Jiao, Yafeng; Qian, Jun; Li, Yong; Jing, H

    2016-01-01

    We study the gain-assisted light transmissions in optomechanical systems, especially the nonlinear higher-order sideband process. We find that: (i) in a single active cavity, the efficiency of the second-order process is considerably enhanced, and the accompanying group delay can surpass that of the probe field, which is unattainable for a lossy cavity (i.e. without any gain); (ii) in an active-passive compound system, the second-order process can be further enhanced by approaching to the gain-loss balance, and hundreds of microsecond of relative delay or advance are achievable between the probe and the second-order signal, indicating an active optomechanical modulator both in frequency and time domains.

  14. Experimental studies on active control of a dynamic system via a time-delayed absorber

    Science.gov (United States)

    Xu, Jian; Sun, Yixia

    2015-04-01

    The traditional passive absorber is fully effective within a narrow and certain frequency band. To solve this problem, a time-delayed acceleration feedback is introduced to convert a passive absorber into an active one. Both the inherent and the intentional time delays are included. The former mainly comes from signal acquiring and processing, computing, and applying the actuation force, and its value is fixed. The latter is introduced in the controller, and its value is actively adjustable. Firstly, the mechanical model is established and the frequency response equations are obtained. The regions of stability are delineated in the plane of control parameters. Secondly, the design scheme of control para- meters is performed to help select the values of the feedback gain and time delay. Thirdly, the experimental studies are conducted. Effects of both negative and positive feedback control are investigated. Experimental results show that the proper choices of control parameters may broaden the effective frequency band of vibration absorption. Moreover, the time-delayed absorber greatly suppresses the resonant response of the primary system when the passive absorber totally fails. The experimental results are in good agreement with the theoretical predictions and numerical simulations.

  15. Quadratic partial eigenvalue assignment problem with time delay for active vibration control

    Science.gov (United States)

    Pratt, J. M.; Singh, K. V.; Datta, B. N.

    2009-08-01

    Partial pole assignment in active vibration control refers to reassigning a small set of unwanted eigenvalues of the quadratic eigenvalue problem (QEP) associated with the second order system of a vibrating structure, by using feedback control force, to suitably chosen location without altering the remaining large number of eigenvalues and eigenvectors. There are several challenges of solving this quadratic partial eigenvalue assignment problem (QPEVAP) in a computational setting which the traditional pole-placement problems for first-order control systems do not have to deal with. In order to these challenges, there has been some work in recent years to solve QPEVAP in a computationally viable way. However, these works do not take into account of the practical phenomenon of the time-delay effect in the system. In this paper, a new "direct and partial modal" approach of the quadratic partial eigenvalue assignment problem with time-delay is proposed. The approach works directly in the quadratic system without requiring transformation to a standard state-space system and requires the knowledge of only a small number of eigenvalues and eigenvectors that can be computed or measured in practice. Two illustrative examples are presented in the context of active vibration control with constant time-delay to illustrate the success of our proposed approach. Future work includes generalization of this approach to a more practical complex time-delay system and extension of this work to the multi-input problem.

  16. Contralateral delay activity tracks the influence of Gestalt grouping principles on active visual working memory representations.

    Science.gov (United States)

    Peterson, Dwight J; Gözenman, Filiz; Arciniega, Hector; Berryhill, Marian E

    2015-10-01

    Recent studies have demonstrated that factors influencing perception, such as Gestalt grouping cues, can influence the storage of information in visual working memory (VWM). In some cases, stationary cues, such as stimulus similarity, lead to superior VWM performance. However, the neural correlates underlying these benefits to VWM performance remain unclear. One neural index, the contralateral delay activity (CDA), is an event-related potential that shows increased amplitude according to the number of items held in VWM and asymptotes at an individual's VWM capacity limit. Here, we applied the CDA to determine whether previously reported behavioral benefits supplied by similarity, proximity, and uniform connectedness were reflected as a neural savings such that the CDA amplitude was reduced when these cues were present. We implemented VWM change-detection tasks with arrays including similarity and proximity (Experiment 1); uniform connectedness (Experiments 2a and 2b); and similarity/proximity and uniform connectedness (Experiment 3). The results indicated that when there was a behavioral benefit to VWM, this was echoed by a reduction in CDA amplitude, which suggests more efficient processing. However, not all perceptual grouping cues provided a VWM benefit in the same measure (e.g., accuracy) or of the same magnitude. We also found unexpected interactions between cues. We observed a mixed bag of effects, suggesting that these powerful perceptual grouping benefits are not as predictable in VWM. The current findings indicate that when grouping cues produce behavioral benefits, there is a parallel reduction in the neural resources required to maintain grouped items within VWM.

  17. Impact of the initial tropospheric zenith path delay on precise point positioning convergence during active conditions

    Science.gov (United States)

    Kalita, J. Z.; Rzepecka, Z.

    2017-04-01

    Tropospheric delay is one of the key factors that influence the convergence time of the precise point positioning (PPP) method. Current models do not allow for the fixing of the zenith path delay tropospheric parameter, leaving the difference between nominal and final value to the estimation process. Here, we present an analysis of several PPP result-sets using the tropospheric parameter’s nominal value adopted from models: VMF1, GPT2w, MOPS, and ZERO-WET. The last variant assumes a zero value for the initial wet part of the zenith delay. The PPP results are subtracted from a solution based on the final tropospheric product from the International GNSS Service (IGS). Several days exhibiting the most active tropospheric conditions were selected for each of the 7 stations located in the mid-latitude Central European region. During the active days, application of the VMF1 model increases the resulting height component’s quality by about 33–36% when compared to the GPT2w and MOPS. The respective improvement in VMF1 latitude and longitude components is 27% and 15%. The average relative deterioration in the result standard deviations between active and calm tropospheric conditions reaches about 20–30% of the former. We discuss the impact of the initial tropospheric parameter’s variance and bias on positioning. In addition, we compare the results with those of other studies over the impact of active tropospheric conditions on the PPP method.

  18. Improved diagnosis of actively bleeding aneurysm on CT angiography using delayed CT images

    Energy Technology Data Exchange (ETDEWEB)

    Kathuria, Sudhir, E-mail: skathur2@jhmi.edu [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Division of Interventional Neuroradiology, Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Deveikis, John P.; Westesson, Per-Lennart [Division of Diagnostic and Interventional Neuroradiology, Department of Imaging Sciences, University of Rochester Medical Center, Rochester, NY 14642 (United States); Gandhi, Dheeraj [Division of Interventional Neuroradiology, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Division of Interventional Neuroradiology, Department of Neurology and Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD (United States)

    2011-08-15

    Computed tomographic angiography (CTA) is being increasingly utilized in the non-invasive diagnosis of aneurysmal subarachnoid hemorrhage (SAH). There are emerging reports of diagnosis of active aneurysmal bleeding on CTA, furthering our understanding of imaging features of active extravasation on cross-sectional studies. We demonstrate imaging characteristics of two such cases of active contrast extravasation from intracranial aneurysms. Additionally, we demonstrate that delayed CT images greatly improve the confidence of this diagnosis by demonstrating pooling of contrast in the subarachnoid space. Prompt recognition and management can improve prognosis of this potentially lethal condition.

  19. Research on Direct Power Control of Three-phase PWM Rectifier with Constant Switch Frequency%三相恒频PWM整流器的直接功率控制研究

    Institute of Scientific and Technical Information of China (English)

    唐雄民; 朱燕飞

    2011-01-01

    A predictive direct power control strategy for three-phase pulse width modulation rectifier was presented. Based on instantaneous active and reactive power theory, the rectifier s active and reactive power variations were predicted in the next sampling period and control vector of rectifier was directly calculated. With control vector of rectifier,space vector modulation was used to generate the required switch pulse of con verter in a constant switching frequency. The impact of sampling delay and online calculation delay on the accu racy of active and reactive power was analyzed,and the compensation method was achieved. Simulation results validate the control strategy and compensation method.%提出了一种基于功率预测模型的三相PWM整流器控制策略.控制策略利用瞬时功率理论预测下一个固定周期内电路的有功和无功变化,直接求取整流器交流侧的电压矢量,并采用空间矢量调制方法来保证整流器工作频率的恒定.还对由于采样、实时计算等原因引起的延时对电路有功和无功的影响进行探讨,并给出了补偿方法.仿真结果验证了控制策略和补偿方法的有效性.

  20. Controlling Synergistic Oxidation Processes for Efficient and Stable Blue Thermally Activated Delayed Fluorescence Devices.

    Science.gov (United States)

    Cui, Lin-Song; Deng, Ya-Li; Tsang, Daniel Ping-Kuen; Jiang, Zuo-Quan; Zhang, Qisheng; Liao, Liang-Sheng; Adachi, Chihaya

    2016-09-01

    Efficient sky-blue organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) display a three orders of magnitude increase in lifetime, which is superior to those of controlled phosphorescent OLEDs used in this study. The combination of electro-oxidation and photo-oxidation of the TADF emitters in their triplet excited-states is suppressed through molecule design and device engineering.

  1. Topologically subordered rectifiable spaces and compactifications

    CERN Document Server

    Lin, Fucai

    2011-01-01

    A topological space $G$ is said to be a {\\it rectifiable space} provided that there are a surjective homeomorphism $\\phi :G\\times G\\rightarrow G\\times G$ and an element $e\\in G$ such that $\\pi_{1}\\circ \\phi =\\pi_{1}$ and for every $x\\in G$ we have $\\phi (x, x)=(x, e)$, where $\\pi_{1}: G\\times G\\rightarrow G$ is the projection to the first coordinate. In this paper, we mainly discuss the rectifiable spaces which are suborderable, and show that if a rectifiable space is suborderable then it is metrizable or a totally disconnected P-space, which improves a theorem of A.V. Arhangel'ski\\v\\i\\ in \\cite{A20092}. As an applications, we discuss the remainders of the Hausdorff compactifications of GO-spaces which are rectifiable, and we mainly concerned with the following statement, and under what condition $\\Phi$ it is true. Statement: Suppose that $G$ is a non-locally compact GO-space which is rectifiable, and that $Y=bG\\setminus G$ has (locally) a property-$\\Phi$. Then $G$ and $bG$ are separable and metrizable. Moreo...

  2. `Didn't Get Expected Answer, Rectify It.': Teaching science content in an elementary science classroom using hands-on activities

    Science.gov (United States)

    Tan, Aik-Ling; Wong, Hwei-Ming

    2012-01-01

    The call for inquiry science to be a part of the school science curriculum is popular in many parts of the world. While some research in this area revealed success stories of students' learning when they are engaged in student-directed, open-ended scientific inquiry activities, others are more sceptical about how these activities impact students' learning in and of science. Using the microanalysis of classroom talk in a grade-six science classroom dealing with the conversion of energy, we illustrate the dilemma in communicative approach used by a teacher when using an inductive hands-on activity to teach canonical science content. We unravel the complexity between dialogic-authoritative approaches in establishing learning as well as the need to fulfil the teaching purposes set for each lesson. Here we illustrate how the use of fine grain analysis of classroom talk and interaction can reveal the details of classroom learning, such as mismatch of teaching purposes and adopting appropriate approach to fulfil the intended teaching purpose.

  3. The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

    DEFF Research Database (Denmark)

    Grier, C.J.; Peterson, B.M.; Pogge, R.W.;

    2013-01-01

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different...

  4. Asymmetric gear rectifies random robot motion

    Science.gov (United States)

    Li, He; Zhang, H. P.

    2013-06-01

    We experimentally study the dynamics of centimetric robots and their interactions with rotary gears through inelastic collisions. Under the impacts of self-propelled robots, a gear with symmetric teeth diffuses with no preferred direction of motion. An asymmetric gear, however, rectifies random motion of nearby robots which, in return, exert a torque on the gear and drive it into unidirectional motion. Rectification efficiency increases with the degree of gear asymmetry. Our work demonstrates that asymmetric environments can be used to rectify and extract energy from random motion of macroscopic self-propelled particles.

  5. DC Motor Drive with PFC Rectifier

    Directory of Open Access Journals (Sweden)

    Lascu Mihaela

    2008-05-01

    Full Text Available The goal of this work is to study theperformances of a hybrid controller used to controlDC Motor drive with a single-phase power factorcorrection rectifier. This study is made usingcomputer simulation (Simulink. The first part isdevoted to the control system of the DC Motors. Inthe second part, the design of the hybrid controllerwill be presented. The third part is the design ofthe fast response single-phase boost power factorcorrection rectifier. The last parts are devoted tosimulation and experimental results.

  6. EFFECTS OF MESSAGE VS ACTIVE EXERCISES ON EXPERIMENTALLY INDUCED DELAYED ONSET OF MUSCLE SORENESS

    Directory of Open Access Journals (Sweden)

    A. Chaturvedi Pilladi *,

    2013-12-01

    Full Text Available Background:To evaluate the effect of massage of versus active exercises on experimentally induced delayedonset of muscle soreness.Method:30 subjects were divided into two groups, Experimental group received Massage and control groupreceived active exercises, results were taken by measurement of pain and functional stair climbing capacity ofknee joint were taken by visual analog score and functional knee rating score.Results:obtained results were analyzed with the use of Paired T-test, which has been carried out to observethetreatment impact between the groups before and after the treatment. After a 4 week treatment period,thesubjects in the Group I (Quadriceps message compared with the subjects in the Group II (Active exercise hadshown a statistically significant improvement with the outcome measures at 0.05 level.Conclusion:Quadriceps massagewas found much effective in decreasing Delayed onset of muscle sorenessthan active exercises.

  7. Delayed mGluR5 activation limits neuroinflammation and neurodegeneration after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Byrnes Kimberly R

    2012-02-01

    Full Text Available Abstract Background Traumatic brain injury initiates biochemical processes that lead to secondary neurodegeneration. Imaging studies suggest that tissue loss may continue for months or years after traumatic brain injury in association with chronic microglial activation. Recently we found that metabotropic glutamate receptor 5 (mGluR5 activation by (RS-2-chloro-5-hydroxyphenylglycine (CHPG decreases microglial activation and release of associated pro-inflammatory factors in vitro, which is mediated in part through inhibition of reduced nicotinamide adenine dinucleotide phosphate (NADPH oxidase. Here we examined whether delayed CHPG administration reduces chronic neuroinflammation and associated neurodegeneration after experimental traumatic brain injury in mice. Methods One month after controlled cortical impact traumatic brain injury, C57Bl/6 mice were randomly assigned to treatment with single dose intracerebroventricular CHPG, vehicle or CHPG plus a selective mGluR5 antagonist, 3-((2-Methyl-4-thiazolylethynylpyridine. Lesion volume, white matter tract integrity and neurological recovery were assessed over the following three months. Results Traumatic brain injury resulted in mGluR5 expression in reactive microglia of the cortex and hippocampus at one month post-injury. Delayed CHPG treatment reduced expression of reactive microglia expressing NADPH oxidase subunits; decreased hippocampal neuronal loss; limited lesion progression, as measured by repeated T2-weighted magnetic resonance imaging (at one, two and three months and white matter loss, as measured by high field ex vivo diffusion tensor imaging at four months; and significantly improved motor and cognitive recovery in comparison to the other treatment groups. Conclusion Markedly delayed, single dose treatment with CHPG significantly improves functional recovery and limits lesion progression after experimental traumatic brain injury, likely in part through actions at mGluR5 receptors

  8. Addictive drugs, arrhythmias, and cardiac inward rectifiers.

    Science.gov (United States)

    Bébarová, Markéta; Hořáková, Zuzana; Kula, Roman

    2016-06-14

    In many addictive drugs including alcohol and nicotine, proarrhythmic effects were reported. This review provides an overview of the current knowledge in this field (with a focus on the inward rectifier potassium currents) to promote the lacking data and appeal for their completion, thus, to improve understanding of the proarrhythmic potential of addictive drugs.

  9. Laserlike Vibrational Instability in Rectifying Molecular Conductors

    DEFF Research Database (Denmark)

    Lu, Jing Tao; Hedegård, Per; Brandbyge, Mads

    2011-01-01

    We study the damping of molecular vibrations due to electron-hole pair excitations in donor-acceptor (D-A) type molecular rectifiers. At finite voltage additional nonequilibrium electron-hole pair excitations involving both electrodes become possible, and contribute to the stimulated emission and...

  10. Linear models of activation cascades: analytical solutions and coarse-graining of delayed signal transduction.

    Science.gov (United States)

    Beguerisse-Díaz, Mariano; Desikan, Radhika; Barahona, Mauricio

    2016-08-01

    Cellular signal transduction usually involves activation cascades, the sequential activation of a series of proteins following the reception of an input signal. Here, we study the classic model of weakly activated cascades and obtain analytical solutions for a variety of inputs. We show that in the special but important case of optimal gain cascades (i.e. when the deactivation rates are identical) the downstream output of the cascade can be represented exactly as a lumped nonlinear module containing an incomplete gamma function with real parameters that depend on the rates and length of the cascade, as well as parameters of the input signal. The expressions obtained can be applied to the non-identical case when the deactivation rates are random to capture the variability in the cascade outputs. We also show that cascades can be rearranged so that blocks with similar rates can be lumped and represented through our nonlinear modules. Our results can be used both to represent cascades in computational models of differential equations and to fit data efficiently, by reducing the number of equations and parameters involved. In particular, the length of the cascade appears as a real-valued parameter and can thus be fitted in the same manner as Hill coefficients. Finally, we show how the obtained nonlinear modules can be used instead of delay differential equations to model delays in signal transduction.

  11. Antioxidant activity and delayed aging effects of hot water extract from Chamaecyparis obtusa var. formosana leaves.

    Science.gov (United States)

    Cheng, Szu-Chin; Li, Wen-Hsuan; Shi, Yeu-Ching; Yen, Pei-Ling; Lin, Huan-You; Liao, Vivian Hsiu-Chuan; Chang, Shang-Tzen

    2014-05-07

    The antioxidant activity and delayed aging effects of hot water extracts from leaves of Chamaecyparis obtusa var. formosana were investigated. Free radical, superoxide radical scavenging, and total phenolic content assays were employed to evaluate the in vitro activities of the extracts. In addition, in vivo assays using the nematode Caenorhabditis elegans were also performed in this study. The results showed that among all soluble fractions obtained from the extracts, the ethyl acetate-soluble fraction has the best in vitro and in vivo antioxidant activities. Moreover, it decreased significantly the deposition of lipofuscin (aging pigment) and extended the lifespan of C. elegans. Bioactivity-guided fractionation yielded six potent antioxidant constituents from the ethyl acetate-soluble fraction, namely, catechin, quercetin, quercetin-3-O-α-rhamnoyranoside, myricetin-3-O-α-rhamnoyranoside, vanillic acid, and 4-hydroxybenzoic acid. Quercetin-3-O-α-rhamnoyranoside pretreatment showed the highest survival of C. elegans upon juglone exposure. Taken together, the results revealed that hot water extracts from C. obtusa var. formosana leaves have the potential to be used as a source for antioxidant or delayed aging health food.

  12. 46 CFR 120.360 - Semiconductor rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Semiconductor rectifier systems. 120.360 Section 120.360... INSTALLATION Power Sources and Distribution Systems § 120.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an adequate heat removal system that prevents overheating. (b) Where...

  13. 46 CFR 129.360 - Semiconductor-rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Semiconductor-rectifier systems. 129.360 Section 129.360... INSTALLATIONS Power Sources and Distribution Systems § 129.360 Semiconductor-rectifier systems. (a) Each semiconductor-rectifier system must have an adequate heat-removal system to prevent overheating. (b) If...

  14. 46 CFR 183.360 - Semiconductor rectifier systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Semiconductor rectifier systems. 183.360 Section 183.360... TONS) ELECTRICAL INSTALLATION Power Sources and Distribution Systems § 183.360 Semiconductor rectifier systems. (a) Each semiconductor rectifier system must have an adequate heat removal system that...

  15. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Qiangqiang Wang

    2016-01-01

    Full Text Available Since excessive reactive oxygen species (ROS is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps, which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction.

  16. Fuzzy variable structure algorithms for active queue management with delay compensation

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the linearized model of the TCP connections through the congested routers, this paper puts forward an active queue management algorithm (FVS-T). The algorithm utilizes the fuzzy variable structure control algorithm with delay factor to compensate time varying round-trip times (RTT) and uncertainties with respect to the number of active TCP sessions. By analyzing the robustness and performance of the control scheme for the nonlinear TCP/AQM model, we show that the proposed design has good performance and robustness, which are central to the notion of AQM. Implementation issues were discussed and ns simulations were provided to validate the design and compare its performance to other peer schemes in different scenarios. The results show that the proposed design significantly outperforms the other congestion schemes in terms of packet loss ratio, throughput and buffer fluctuation.

  17. Vasodilatation vs. immunotherapy to prevent delayed graft function: delayed graft function as an indication of immune activation.

    Science.gov (United States)

    McCune, Thomas R; Wombolt, Duane G; Whelan, Thomas V; Thacker, Leroy R; Colonna, John O

    2005-01-01

    Delayed renal allograft function (DGF) is a factor for acute rejection and chronic allograft nephropathy. Cold ischemia time (CIT) is associated with an increased in DGF. Twenty patients receiving allografts with CIT>12 were enrolled in a double-blinded, randomized (1:1), placebo-controlled study to assess vasodilatation with fenoldopam (Abbott; dopamine-1 receptor agonist) on DGF. Fenoldopam infusion began at arterial anastomosis at 0.025 microg/kg/min and titrated to 0.1 microg/kg/min continued for 48 h postop (PO). Immunosuppression included steriods, MMF, and calcinurin inhibitors begun 36 h PO. Antibody induction (AI) using antithymocyte globulin (rabbit) (AT-G(r); Sangstat) was added halfway through the study to African-Americans and for PRA>40%. The need for dialysis, cumulative urine output (UOP), and creatinine (Cr) at PO day 7, 14, and 30 were compared. Eighteen patients completed the study drug infusion. Demographics of groups were not different. There was no difference between fenoldopam and controls for dialysis, UOP at 48 and 72 h, or Cr at 7, 14, or 30 days. There was a difference in UOP when AI (n=7) was compared to non-AI (n=11). At 48 h non-AI UOP 4796+/-3284 ml compared to AI UOP 8960+/-5130 ml (p=0.050). At 72 h, non-AI patients had UOP of 6824+/-4547 ml compared to AI patients with UOP of 12196+/-5868 ml (p=0.044). There was a trend to a lower Cr at day 7 for AI 2.7+/-2.1mg/dl compared to 4.9+/-3.0 mg/dl in non-AI (p=0.11). There was no difference in dialysis or Cr at day 14 and 30 between the AI and non-AI patients. AI with AT-G(r) significantly increases UOP in allografts with CIT>12 h, whereas vasodilatation did not. Therapy for DGF may include AT-G(r) AI.

  18. Multi-objective H ∞ control for vehicle active suspension systems with random actuator delay

    Science.gov (United States)

    Li, Hongyi; Liu, Honghai; Hand, Steve; Hilton, Chris

    2012-12-01

    This article is concerned with the problem of multi-objective H ∞ control for vehicle active suspension systems with random actuator delay, which can be represented by signal probability distribution. First, the dynamical equations of a quarter-car suspension model are established for the control design purpose. Secondly, when taking into account vehicle performance requirements, namely, ride comfort, suspension deflection and the probability distributed actuator delay, we present the corresponding dynamic system, which will be transformed to the stochastic system for the problem of multi-objective H ∞ controller design. Third, based on the stochastic stability theory, the state feedback controller is proposed to render that the closed-loop system is exponentially stable in mean-square while simultaneously satisfying H ∞ performance and the output constraint requirement. The presented condition is expressed in the form of convex optimisation problems so that it can be efficiently solved via standard numerical software. Finally, a practical design example is given to demonstrate the effectiveness of the proposed method.

  19. Direct Measurement of the X-ray Time-Delay Transfer Function in Active Galactic Nuclei

    CERN Document Server

    Legg, E; Turner, T J; Giustini, M; Reeves, J N; Kraemer, S B

    2012-01-01

    The origin of the observed time lags, in nearby active galactic nuclei (AGN), between hard and soft X-ray photons is investigated using new XMM-Newton data for the narrow-line Seyfert I galaxy Ark 564 and existing data for 1H0707-495 and NGC 4051. These AGN have highly variable X-ray light curves that contain frequent, high peaks of emission. The averaged light curve of the peaks is directly measured from the time series, and it is shown that (i) peaks occur at the same time, within the measurement uncertainties, at all X-ray energies, and (ii) there exists a substantial tail of excess emission at hard X-ray energies, which is delayed with respect to the time of the main peak, and is particularly prominent in Ark 564. Observation (i) rules out that the observed lags are caused by Comptonization time delays and disfavors a simple model of propagating fluctuations on the accretion disk. Observation (ii) is consistent with time lags caused by Compton-scattering reverberation from material a few thousand light-se...

  20. Menger curvature and rectifiability in metric spaces

    OpenAIRE

    2012-01-01

    We show that for any metric space $X$ the condition \\[ \\int_X\\int_X\\int_X c(z_1,z_2,z_3)^2\\, d\\Hm z_1\\, d\\Hm z_2\\, d\\Hm z_3 < \\infty, \\] where $c(z_1,z_2,z_3)$ is the Menger curvature of the triple $(z_1,z_2,z_3)$, guarantees that $X$ is rectifiable.

  1. Rotating field transformers eliminate rectifier harmonics

    Energy Technology Data Exchange (ETDEWEB)

    Pastor, C.E. [Westinghouse Motor Co., Round Rock, TX (United States); Buckle, K.A. [Univ. of South Florida, Tampa, FL (United States); Luce, J.W. [Luce (John W.), Tampa, FL (United States)

    1995-10-01

    The rotating field transformer is a static device that has the same magnetic field as a three phase motor. When used to feed diode rectifiers, it converts ac to dc with low ripple on the output voltage and remarkably low current distortion on the input. Filters are not needed. This is a timely development because it is an economical and very effective solution to the growing problem of power system harmonics.

  2. Non-fragile multi-objective static output feedback control of vehicle active suspension with time-delay

    Science.gov (United States)

    Kong, Yongsu; Zhao, Dingxuan; Yang, Bin; Han, Chenghao; Han, Kyongwon

    2014-07-01

    This paper presents an approach to design a delay-dependent non-fragile H∞/L2-L∞ static output feedback (SOF) controller for active suspension with input time-delay. The control problem of quarter-car active suspension with actuator time-delay is formulated to a H∞/L2-L∞ control problem. By employing a delay-dependent Lyapunov function, new existence conditions of delay-dependent non-fragile SOF H∞ controller and L2-L∞ controller are derived, respectively, in terms of the feasibility of bilinear matrix inequalities (BMIs). Then, a procedure based on linear matrix inequality optimisation and a hybrid algorithm of the particle swarm optimisation and differential evolution is used to solve an optimisation problem with BMI constraints. Design and simulation results of non-fragile H∞/L2-L∞ controller for active suspension show that the designed controller not only can achieve the optimal performance and stability of the closed-loop system in spite of the existence of the actuator time-delay, but also has significantly improved the non-fragility characteristics over controller perturbations.

  3. Activated RET/PTC oncogene elicits immediate early and delayed response genes in PC12 cells.

    Science.gov (United States)

    Califano, D; Monaco, C; de Vita, G; D'Alessio, A; Dathan, N A; Possenti, R; Vecchio, G; Fusco, A; Santoro, M; de Franciscis, V

    1995-07-06

    The expression of the receptor-like tyrosine kinase RET is associated with tumors, tissues or cell lines of neural crest origin. In addition RET products (Ret) are involved in determining cell fate during the differentiation of the enteric nervous system and during renal organogenesis. However, as yet, no direct evidence exists to indicate that the Ret kinase activity might interfere in a specific way with cellular differentiation, or proliferation, of a neural crest derived cell line. By using two constitutively activated forms of RET (RET/PTC1 and RET/PTC3) in transient transfection experiments, we have obtained evidence that active RET could reprogramme the gene expression pattern in the rat pheochromocytoma PC12 cell line. Transcription driven by gene promoters, such as NGFI-A and vgf, which belong, respectively, to primary and delayed response genes to nerve growth factor (NGF), and by the neuron-specific enolase (NSE) promoter, is rapidly induced by the expression of activated RET oncogenes. This induction is not elicited in other non neural derived cell types tested. We also demonstrate that endogenous ras activity is required for RET induction of these neural markers. Finally, in the RET/PTC transfected PC12 cells, NGF is unable to induce further their transcription. This suggests that RET/PTC could share an intracellular signalling pathway with the NGF-receptor.

  4. Active control of periodic fan noise in laptops: spectral width requirements in delayed buffer implementation

    Directory of Open Access Journals (Sweden)

    H. A. Cordourier‐Maruri

    2009-08-01

    Full Text Available An active control system intended for the reduction of strictly periodic noise components in computer cooling fans is described,which is based on high‐performance digital sound device architectures found in some personal computers. The systemovercomes causality and synchronization constrains imposed by delayed buffering, as usually found in computer audioprocessing. Performance of the system is demonstrated and evaluated through measurements in a physical implementation ofactive noise control of synthetic tones combined with laptop fan noise, carried out under anechoic and slightly reverberantconditions. Tests on other types of tonal noise sources, like an electrical transformer, were also carried out. However, its widerapplicability to the cancellation of tonal noise has been proved compromised by weak periodicity issues found and reported inthis work. Also, a study of noise spectral width requirements for successful operation is presented.

  5. Queue size and delay analysis for a communication system subject to traffic activity mode changes

    Science.gov (United States)

    Zukerman, M.; Rubin, I.

    1986-06-01

    A discrete single-server queueing/communication system in which the arrival distribution is changing stochastically with time is considered. The distribution of the number of messages to arrive within a time slot depends on a traffic activity process of modes. This process of modes is a two-state Markov chain: mode 0 and mode 1, which represent light and heavy traffic conditions, respectively. The transition probabilities of this Markov chain, or mode duration parameters (MDP's) determine the distribution of the duration of time the process stays in each mode. Expressions for the z-transform, expectation, and variance are obtained for the steady-state queue size and delay. A special consideration is given to the effect of the MDPs on the system performance, and the limiting cases (where the MDPs approach zero) are studied.

  6. The activation of visual face memory and explicit face recognition are delayed in developmental prosopagnosia.

    Science.gov (United States)

    Parketny, Joanna; Towler, John; Eimer, Martin

    2015-08-01

    Individuals with developmental prosopagnosia (DP) are strongly impaired in recognizing faces, but the causes of this deficit are not well understood. We employed event-related brain potentials (ERPs) to study the time-course of neural processes involved in the recognition of previously unfamiliar faces in DPs and in age-matched control participants with normal face recognition abilities. Faces of different individuals were presented sequentially in one of three possible views, and participants had to detect a specific Target Face ("Joe"). EEG was recorded during task performance to Target Faces, Nontarget Faces, or the participants' Own Face (which had to be ignored). The N250 component was measured as a marker of the match between a seen face and a stored representation in visual face memory. The subsequent P600f was measured as an index of attentional processes associated with the conscious awareness and recognition of a particular face. Target Faces elicited reliable N250 and P600f in the DP group, but both of these components emerged later in DPs than in control participants. This shows that the activation of visual face memory for previously unknown learned faces and the subsequent attentional processing and conscious recognition of these faces are delayed in DP. N250 and P600f components to Own Faces did not differ between the two groups, indicating that the processing of long-term familiar faces is less affected in DP. However, P600f components to Own Faces were absent in two participants with DP who failed to recognize their Own Face during the experiment. These results provide new evidence that face recognition deficits in DP may be linked to a delayed activation of visual face memory and explicit identity recognition mechanisms.

  7. Silencing of doublecortin-like (DCL results in decreased mitochondrial activity and delayed neuroblastoma tumor growth.

    Directory of Open Access Journals (Sweden)

    Carla S Verissimo

    Full Text Available Doublecortin-like (DCL is a microtubule-binding protein crucial for neuroblastoma (NB cell proliferation. We have investigated whether the anti-proliferative effect of DCL knockdown is linked to reduced mitochondrial activity. We found a delay in tumor development after DCL knockdown in vivo in doxycycline-inducible NB tumor xenografts. To understand the mechanisms underlying this tumor growth retardation we performed a series of in vitro experiments in NB cell lines. DCL colocalizes with mitochondria, interacts with the mitochondrial outer membrane protein OMP25/ SYNJ2BP and DCL knockdown results in decreased expression of genes involved in oxidative phosphorylation. Moreover, DCL knockdown decreases cytochrome c oxidase activity and ATP synthesis. We identified the C-terminal Serine/Proline-rich domain and the second microtubule-binding area as crucial DCL domains for the regulation of cytochrome c oxidase activity and ATP synthesis. Furthermore, DCL knockdown causes a significant reduction in the proliferation rate of NB cells under an energetic challenge induced by low glucose availability. Together with our previous studies, our results corroborate DCL as a key player in NB tumor growth in which DCL controls not only mitotic spindle formation and the stabilization of the microtubule cytoskeleton, but also regulates mitochondrial activity and energy availability, which makes DCL a promising molecular target for NB therapy.

  8. Sumoylation delays the ATF7 transcription factor subcellular localization and inhibits its transcriptional activity.

    Science.gov (United States)

    Hamard, Pierre-Jacques; Boyer-Guittaut, Michaël; Camuzeaux, Barbara; Dujardin, Denis; Hauss, Charlotte; Oelgeschläger, Thomas; Vigneron, Marc; Kedinger, Claude; Chatton, Bruno

    2007-01-01

    Over the past few years, small ubiquitin-like modifier (SUMO) modification has emerged as an important regulator of diverse pathways and activities including protein localization and transcriptional regulation. We identified a consensus sumoylation motif (IKEE), located within the N-terminal activation domain of the ATF7 transcription factor and thus investigated the role of this modification. ATF7 is a ubiquitously expressed transcription factor, homologous to ATF2, that binds to CRE elements within specific promoters. This protein is able to heterodimerize with Jun or Fos proteins and its transcriptional activity is mediated by interaction with TAF12, a subunit of the general transcription factor TFIID. In the present article, we demonstrate that ATF7 is sumoylated in vitro (using RanBP2 as a E3-specific ligase) and in vivo. Moreover, we show that ATF7 sumoylation affects its intranuclear localization by delaying its entry into the nucleus. Furthermore, SUMO conjugation inhibits ATF7 transactivation activity by (i) impairing its association with TAF12 and (ii) blocking its binding-to-specific sequences within target promoters.

  9. Resveratrol-induced augmentation of telomerase activity delays senescence of endothelial progenitor cells

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-bin; ZHU Li; HUANG Jun; YIN Yi-gang; KONG Xiang-qing; RONG Qi-fei; SHI Ai-wu; CAO Ke-jiang

    2011-01-01

    Background Previous studies have shown that resveratrol increases endothelial progenitor cell (EPC) numbers and functional activity.Increased EPC numbers and activity are associated with the inhibition of EPC senescence.In this study,we investigated the effect of resveratrol on the senescence of EPCs,leading to potentiation of cellular function.Methods EPCs were isolated from human peripheral blood and identified immunocytochemically.EPCs were incubated with resveratrol (1,10,and 50 μmol/L) or control for specified times.After in vitro cultivation,acidic β-galactosidase staining revealed the extent of senescence in the cells.To gain further insight into the underlying mechanism of the effect of resveratrol,we measured telomerase activity using a polymerase chain reaction (PCR)-enzyme-linked immunosorbent assay (ELISA) technique.Furthermore,we measured the expression of human telomerase reverse transcriptase (hTERT) and the phosphorylation of Akt by immunoblotting.Results Resveratrol dose-dependently inhibited the onset of EPC senescence in culture.Resveratrol also significantly increased telomerase activity.Interestingly,quantitative real-time PCR analysis demonstrated that resveratrol dose-dependently increased the expression of the catalytic subunit,hTERT,an effect that was significantly inhibited by pharmacological phosphatidylinositol 3-kinase (PI3-K) blockers (wortmannin).The expression of hTERT is regulated by the PI3-K/Akt pathway; therefore,we examined the effect of resveratrol on Akt activity in EPCs.Immunoblotting analysis revealed that resveratrol led to dose-dependent phosphorylation and activation of Akt in EPCs.Conclusion Resveratrol delayed EPCs senescence in vitro,which may be dependent on telomerase activation.

  10. Three -Phase PFC Rectifier with Phase - Modular Y-Rectifier for LED Lamp

    Directory of Open Access Journals (Sweden)

    Narin Watanakul

    2015-10-01

    Full Text Available The paper was to study ac/dc three phase PFC rectifier for LED lamp. The performance normally of the rectifier having is current low quality and low power factor and high total harmonics distortion current. Therefore, the objectives in this a paper going to improving power factor and reduce harmonics current. In this paper to propose power factor correction (PFC with phase- modular Y-rectifier, boost type converter circuit using by one cycle control (OCC. For high performance method and tested of the result for realize that can solve power factor and reduce harmonic current. The research papers, conclusions for study and evaluate the circuit can be operation and suitable for use with LED 50 W (LED lamp. The data collected by MATLAB Simulation are used in comparison with the experimental tester of results.

  11. DIRECT MEASUREMENT OF THE X-RAY TIME-DELAY TRANSFER FUNCTION IN ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Legg, E.; Miller, L. [Department of Physics, Oxford University, Keble Road, Oxford OX1 3RH (United Kingdom); Turner, T. J.; Giustini, M.; Reeves, J. N. [Department of Physics, University of Maryland Baltimore County, Baltimore, MD 21250 (United States); Kraemer, S. B. [Institute for Astrophysics and Computational Sciences, Department of Physics, The Catholic University of America, Washington, DC 20064 (United States)

    2012-11-20

    The origin of the observed time lags, in nearby active galactic nuclei (AGNs), between hard and soft X-ray photons is investigated using new XMM-Newton data for the narrow-line Seyfert I galaxy Ark 564 and existing data for 1H 0707-495 and NGC 4051. These AGNs have highly variable X-ray light curves that contain frequent, high peaks of emission. The averaged light curve of the peaks is directly measured from the time series, and it is shown that (1) peaks occur at the same time, within the measurement uncertainties, at all X-ray energies, and (2) there exists a substantial tail of excess emission at hard X-ray energies, which is delayed with respect to the time of the main peak, and is particularly prominent in Ark 564. Observation (1) rules out that the observed lags are caused by Comptonization time delays and disfavors a simple model of propagating fluctuations on the accretion disk. Observation (2) is consistent with time lags caused by Compton-scattering reverberation from material a few thousand light-seconds from the primary X-ray source. The power spectral density and the frequency-dependent phase lags of the peak light curves are consistent with those of the full time series. There is evidence for non-stationarity in the Ark 564 time series in both the Fourier and peaks analyses. A sharp 'negative' lag (variations at hard photon energies lead soft photon energies) observed in Ark 564 appears to be generated by the shape of the hard-band transfer function and does not arise from soft-band reflection of X-rays. These results reinforce the evidence for the existence of X-ray reverberation in type I AGN, which requires that these AGNs are significantly affected by scattering from circumnuclear material a few tens or hundreds of gravitational radii in extent.

  12. Cesium blockade of delayed outward currents and electrically induced pacemaker activity in mammalian ventricular myocardium.

    Science.gov (United States)

    Meier, C F; Katzung, B G

    1981-05-01

    The effects of Cs+, 5-25 mM, were studied in cat and guinea pig papillary muscles using voltage clamp and current clamp techniques. In solutions containing normal K+, the major effects of Cs+ were depolarization of the resting potential and reduction of the delayed outward current (ixl) between -80 and -20 mV. Both inward and outward portions of the isochronal current voltage relation (l-s clamps) were reduced by extracellular Cs+. This resulted in a substantial reduction of inward rectification and, by subtraction from the normal I-V relationship, the definition of a Cs+-sensitive component of current. Under current clamp conditions, 5-10 mM Cs+ produced a dose-dependent slowing of repetitive firing induced by depolarization. At higher concentrations (25 mM) the resting potential was depolarized and repetitive activity could not be induced by further depolarization. However, release of hyperpolarizing pulses was followed by prolonged bursts of repetitive action potentials, suggesting partial reversal of blockade or participation of another pacemaker process. The experimental results and a numerical simulation show that under readily attainable conditions, reduction in an outward pacemaker current may slow pacemaker activity.

  13. Three-Phase Back PWM-PFC Rectifier

    Institute of Scientific and Technical Information of China (English)

    Yasuyuki Nishida

    2005-01-01

    A new 3-phase back (or current-source-type) PWM-PFC rectifier is proposed in this paper. The necessity,the advantages and disadvantages of this type PWM rectifier are discussed first.Then,the new power circuit topology and the modulation scheme to eliminate or mitigate the disadvantages and obtain further new advantages of the buck PWM rectifier are introduced.The features of the new rectifier, i.e., high efficiency, simple modulation process, robustness of the line-current modulation for distortion of the utility voltages and DC current ripples have been confirmed through experimental results obtained from a 12kW prototype.

  14. Properties of rectified averaging of an evoked-type signal: theory and application to the vestibular-evoked myogenic potential.

    Science.gov (United States)

    Colebatch, J G

    2009-11-01

    The properties of rectified averages were investigated using the VEMP (vestibular-evoked myogenic potential) as an example of an evoked-type response. Recordings were made of surface EMG from the sternocleidomastoid (SCM) muscles of six volunteers, unstimulated, at different levels of tonic activation and then in response to clicks of different intensities. The stochastic properties of the surface EMG recorded were shown to be well modelled using a zero mean normal distribution with a standard deviation equivalent to the mean RMS (root mean squared) value (mean residual error variance 0.87%). Assuming a normal distribution, equations were derived for the expected value of both the rectified and RMS average with the addition of constant waveforms of different sizes. A simulation using recorded EMG and added sine waves of different amplitudes demonstrated that the equations predicted the rectified averages accurately. It also confirmed the importance of the relative amplitude of the added signal in determining whether it was detected using rectified averages. The same equations were then applied to actual data consisting of VEMPs of different relative amplitudes recorded from the volunteers. Whilst the signal-to-noise ratio (measured by corrected amplitude) was a major determinant of the nature of the rectified average, consistent deviations were detected between the predicted and actual rectified averages. Deviations from predicted values indicated that the VEMP did not behave simply like a constant signal added to tonic background EMG. A more complicated model, which included temporal jitter as well as inhibition of background EMG during the VEMP, was required to fit the physiological recordings. Rectified averages are sensitive to physiological properties, which are not apparent when using unrectified averages alone. Awareness of the properties of rectified averages should improve their interpretation.

  15. High-Efficiency Blue Organic Light-Emitting Diodes Based on Thermally Activated Delayed Fluorescence from Phenoxaphosphine and Phenoxathiin Derivatives.

    Science.gov (United States)

    Lee, Sae Youn; Adachi, Chihaya; Yasuda, Takuma

    2016-06-01

    High-efficiency blue thermally activated delayed fluorescence (TADF) molecules, consisting of phenoxaphosphine oxide and phenoxathiin dioxide as acceptor units and 9,9-dimethylacridan as a donor unit, are reported. Maximum external electroluminescence quantum efficiencies of up to 20.5% are achieved in blue organic light-emitting diodes (OLEDs) by employing these materials as TADF emitters.

  16. High Voltage GaN Schottky Rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

    1999-10-25

    Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

  17. Impact of size and delay on neural activity in the rat limbic corticostriatal system

    Directory of Open Access Journals (Sweden)

    Matthew R Roesch

    2011-12-01

    Full Text Available A number of factors influence an animal’s economic decisions. Two most commonly studied are the magnitude of and delay to reward. To investigate how these factors are represented in the firing rates of single neurons, we devised a behavioral task that independently manipulated the expected delay to and size of reward. Rats perceived the differently delayed and sized rewards as having different values and were more motivated under short-delay and big-reward conditions than under long-delay and small-reward conditions as measured by percent choice, accuracy and reaction time. Since the creation of this task, we have recorded from several different brain areas including, orbitofrontal cortex, striatum, amygdala, substantia nigra pars reticulata, and midbrain dopamine neurons. Here, we review and compare those data with a substantial focus on those areas that have been shown to be critical for performance on classic time discounting procedures and provide a potential mechanism by which they might interact when animals are deciding between differently delayed rewards. We found that most brain areas in the cortico-limbic circuit encode both the magnitude and delay to reward delivery in one form or another, but only a few encode them together at the single neuron level.

  18. Efficient HOMO-LUMO separation by multiple resonance effect toward ultrapure blue thermally activated delayed fluorescence

    Science.gov (United States)

    Hatakeyama, Takuji; Ikuta, Toshiaki; Shiren, Kazushi; Nakajima, Kiichi; Nomura, Shintaro; Ni, Jingping

    2016-09-01

    Organic light-emitting diodes (OLEDs) play an important role in the new generation of flat-panel displays. Conventional OLEDs employing fluorescent materials together with triplet-triplet annihilation suffer from a relatively low internal quantum efficiency (IQE) of 62.5%. On the other hand, the IQE of OLEDs employing phosphorescent or thermally activated delayed fluorescence (TADF) materials can reach 100%. However, these materials exhibit very broad peaks with a full-width at half-maximum (FWHM) of 70-100 nm and cannot satisfy the color-purity requirements for displays. Therefore, the latest commercial OLED displays employ blue fluorescent materials with a relatively low IQE, and efficient blue emitters with a small FWHM are highly needed. In our manuscript, we present organic molecules that exhibit ultrapure blue fluorescence based on TADF. These molecules consist of three benzene rings connected by one boron and two nitrogen atoms, which establish a rigid polycyclic framework and significant localization of the highest occupied and lowest unoccupied molecular orbitals by a multiple resonance effect. An OLED device based on the new emitter exhibits ultrapure blue emission at 467 nm with an FWHM of 28 nm, Commission Internationale de l'Eclairage (CIE) coordinates of (0.12, 0.13), and an IQE of 100%, which represent record-setting performance for blue OLED devices.

  19. Near Real-Time Nondestructive Active Inspection Technologies Utilizing Delayed γ-Rays and Neutrons for Advanced Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Alan [Idaho State Univ., Pocatello, ID (United States). Idaho Accelerator Center, Dept. of Physics; Reedy, E. T.E. [Idaho State Univ., Pocatello, ID (United States). Dept. of Phyics, Idaho Accelerator Center; Mozin, V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Tobin, S. J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Nuclear Nonproliferation

    2015-02-12

    In this two year project, the research team investigated how delayed γ-rays from short-lived fission fragments detected in the short interval between irradiating pulses can be exploited for advanced safeguards technologies. This program contained experimental and modeling efforts. The experimental effort measured the emitted spectra, time histories and correlations of the delayed γ-rays from aqueous solutions and solid targets containing fissionable isotopes. The modeling effort first developed and benchmarked a hybrid Monte Carlo simulation technique based on these experiments. The benchmarked simulations were then extended to other safeguards scenarios, allowing comparisons to other advanced safeguards technologies and to investigate combined techniques. Ultimately, the experiments demonstrated the possible utility of actively induced delayed γ-ray spectroscopy for fissionable material assay.

  20. THE STRUCTURE OF THE BROAD-LINE REGION IN ACTIVE GALACTIC NUCLEI. I. RECONSTRUCTED VELOCITY-DELAY MAPS

    Energy Technology Data Exchange (ETDEWEB)

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; De Rosa, G.; Martini, Paul; Kochanek, C. S.; Zu, Y.; Shappee, B.; Beatty, T. G.; Salvo, C. Araya; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Ave, Columbus, OH 43210 (United States); Horne, Keith [SUPA Physics and Astronomy, University of St. Andrews, Fife, KY16 9SS Scotland (United Kingdom); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Denney, K. D. [Marie Curie Fellow at the Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Siverd, R. [Department of Physics and Astronomy, Vanderbilt University, 5301 Stevenson Center, Nashville, TN 37235 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan - Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); and others

    2013-02-10

    We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C 120, and PG 2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H{beta} emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C 120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II {lambda}4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG 2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C 120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

  1. Recovery Act: High-Efficiency, Wideband Three-Phase Rectifiers and Adaptive Rectifier Management for Telecomm Central Office and Large Data Center Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mark A. Johnson

    2012-06-29

    Lineage Power and Verizon teamed up to address a DOE funding opportunity focused on improving the power conversion chain in telecommunications facilities and data centers. The project had three significant elements: the design and development of high efficiency and high power three-phase rectifiers by Lineage Power, design and development of software to optimize overall plant energy efficiency by Lineage Power, and a field trial in active Verizon telecommunications facilities where energy consumption was measured before and after efficiency upgrades.

  2. CONSENSUS OF THE SECOND-ORDER MULTI-AGENT SYSTEMS WITH AN ACTIVE LEADER AND COUPLING TIME DELAY

    Institute of Scientific and Technical Information of China (English)

    郭万里; 肖海军; 陈士华

    2014-01-01

    This article investigates the consensus problem of the second-order multi-agent systems with an active leader and coupling time delay in direct graph. One decentralized state control rule is constructed for each agent to track the active leader and it is proved that the proposed control scheme enables the consensus to be obtained when the adjacency topology is fixed/switched. Simulation results show effectiveness of the proposed theoretical analysis.

  3. High-Efficiency Harmonically Terminated Diode and Transistor Rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    Roberg, M; Reveyrand, T; Ramos, I; Falkenstein, EA; Popovic, Z

    2012-12-01

    This paper presents a theoretical analysis of harmonically terminated high-efficiency power rectifiers and experimental validation on a class-C single Schottky-diode rectifier and a class-F-1 GaN transistor rectifier. The theory is based on a Fourier analysis of current and voltage waveforms, which arise across the rectifying element when different harmonic terminations are presented at its terminals. An analogy to harmonically terminated power amplifier (PA) theory is discussed. From the analysis, one can obtain an optimal value for the dc load given the RF circuit design. An upper limit on rectifier efficiency is derived for each case as a function of the device on-resistance. Measured results from fundamental frequency source-pull measurement of a Schottky diode rectifier with short-circuit terminations at the second and third harmonics are presented. A maximal device rectification efficiency of 72.8% at 2.45 GHz matches the theoretical prediction. A 2.14-GHz GaN HEMT rectifier is designed based on a class-F-1 PA. The gate of the transistor is terminated in an optimal impedance for self-synchronous rectification. Measurements of conversion efficiency and output dc voltage for varying gate RF impedance, dc load, and gate bias are shown with varying input RF power at the drain. The rectifier demonstrates an efficiency of 85% for a 10-W input RF power at the transistor drain with a dc voltage of 30 V across a 98-Omega resistor.

  4. Hot electron pump: a plasmonic rectifying antenna (Presentation Recording)

    Science.gov (United States)

    Yanik, Ahmet A.; Hossain, Golam I.

    2015-09-01

    Plasmonic nanostructures have been widely explored to improve absorption efficiency of conventional solar cells, either by employing them as a light scatterer, or as a source of local field enhancement. Unavoidable ohmic loss associated with the plasmonic metal nanostructures in visible spectrum, limits the efficiency improvement of photovoltaic devices by employing this local photon density of states (LDOS) engineering approach. Instead of using plasmonic structures as efficiency improving layer, recently, there has been a growing interest in exploring plasmoinc nanoparticle as the active medium for photovoltaic device. By extracting hot electrons that are created in metallic nanoparticles in a non-radiative Landau decay of surface plasmons, many novel plasmonic photovoltaic devices have been proposed. Moreover, these hot electrons in metal nanoparticles promises high efficiency with a spectral response that is not limited by the band gap of the semiconductors (active material of conventional solar cell). In this work, we will show a novel photovoltaic configuration of plasmonic nanoparticle that acts as an antenna by capturing free space ultrahigh frequency electromagnetic wave and rectify them through an ultrafast hot electron pump and eventually inject DC current in the contact of the device. We will introduce a bottom-up quantum mechanical approach model to explain fundamental physical processes involved in this hot electron pump rectifying antenna and it's ultrafast dynamics. Our model is based on non-equilibrium Green's function formalism, a robust theoretical framework to investigate transport and design nanoscale electronic devices. We will demonstrate some fundamental limitations that go the very foundations of quantum mechanics.

  5. Keppen-Lubinsky Syndrome Is Caused by Mutations in the Inwardly Rectifying K+ Channel Encoded by KCNJ6

    OpenAIRE

    Masotti, Andrea; Uva, Paolo; Davis-Keppen, Laura; Basel-Vanagaite, Lina; Cohen, Lior; Pisaneschi, Elisa; Celluzzi, Antonella; Bencivenga, Paola; Fang, Mingyan; Tian, Mingyu; Xu, Xun; Cappa, Marco; Dallapiccola, Bruno

    2015-01-01

    Keppen-Lubinsky syndrome (KPLBS) is a rare disease mainly characterized by severe developmental delay and intellectual disability, microcephaly, large prominent eyes, a narrow nasal bridge, a tented upper lip, a high palate, an open mouth, tightly adherent skin, an aged appearance, and severe generalized lipodystrophy. We sequenced the exomes of three unrelated individuals affected by KPLBS and found de novo heterozygous mutations in KCNJ6 (GIRK2), which encodes an inwardly rectifying potassi...

  6. Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity.

    Science.gov (United States)

    Pittman, Phillip R; Fisher, Diana; Quinn, Xiaofei; Schmader, Trevor; Barrera-Oro, Julio G

    2013-10-17

    We describe the Bacillus anthracis protective antigen IgG antibody response and the B. anthracis lethal toxin neutralization activity to a delayed dose of anthrax vaccine adsorbed (AVA, BioThrax(®)) using validated assays. 373 individuals received 1, 2, or 3 priming doses, 18-24 months afterward, they received a delayed dose of AVA. Overall, 23.6% of subjects showed detectable anti-PA IgG before the boost, compared to 99.2% (P<0.0001) 28 days after the boost. Geometric mean anti-PA IgG concentration (GMC) was 1.66 μg/mL before and 887.82 μg/mL after the boost (P<0.0001). The proportion of individuals with four-fold increase in GMC following the boost ranged from 93.8% to 100%. Robust anti-PA IgG levels and B. anthracis lethal toxin neutralization activity are induced when an AVA dose is delayed as long as two years. These data support continuing with the vaccination schedule when a dose is delayed as long as two years rather than restarting the series.

  7. Bivariate phase-rectified signal averaging

    CERN Document Server

    Schumann, Aicko Y; Bauer, Axel; Schmidt, Georg

    2008-01-01

    Phase-Rectified Signal Averaging (PRSA) was shown to be a powerful tool for the study of quasi-periodic oscillations and nonlinear effects in non-stationary signals. Here we present a bivariate PRSA technique for the study of the inter-relationship between two simultaneous data recordings. Its performance is compared with traditional cross-correlation analysis, which, however, does not work well for non-stationary data and cannot distinguish the coupling directions in complex nonlinear situations. We show that bivariate PRSA allows the analysis of events in one signal at times where the other signal is in a certain phase or state; it is stable in the presence of noise and impassible to non-stationarities.

  8. Structural Optimization of Non-Newtonian Rectifiers

    DEFF Research Database (Denmark)

    Jensen, Kristian Ejlebjærg; Okkels, Fridolin

    . In this context it is natural to look for other sources of non-linearity and one possibility is to introduce a non-Newtonian working fluid. Non-Newtonian properties are due to stretching of large particles/molecules in the fluid and this is commonly seen for biological samples in “lab-on-a-chip” systems....... The strength of non-Newtonian effects does not depend on the device size. Furthermore a non-Newtonian working fluid removes symmetry properties such that geometry influence is reintroduced, and indeed non-Newtonian effects have been used in experimentally realized microfluidic rectitifiers[1]. The rectifiers...... optimization, which is a kind of design optimization where nothing is assumed about the topology of the design. We will apply a high-level implementation of topology optimization using the density method in a commercial finite element package[2]. However, the modeling of non-Newtonian fluids remains a major...

  9. Myocellular enzyme leakage, polymorphonuclear neutrophil activation and delayed onset muscle soreness induced by isokinetic eccentric exercise.

    Science.gov (United States)

    Croisier, J L; Camus, G; Deby-Dupont, G; Bertrand, F; Lhermerout, C; Crielaard, J M; Juchmès-Ferir, A; Deby, C; Albert, A; Lamy, M

    1996-01-01

    To address the question of whether delayed onset muscular soreness (DOMS) following intense eccentric muscle contraction could be due to increased production of the arachidonic acid derived product prostaglandin E2 (PGE2). 10 healthy male subjects were submitted to eccentric and concentric isokinetic exercises on a Kin Trex device at 60 degrees/s angular velocity. Exercise consisted of 8 stages of 5 maximal contractions of the knee extensor and flexor muscle groups of both legs separated by 1 min rest phases. There was an interval of at least 30 days between eccentric and concentric testing, and the order of the two exercise sessions was randomly assigned. The subjective presence and intensity of DOMS was evaluated using a visual analogue scale, immediately, following 24 h and 48 h after each test. Five blood samples were drawn from an antecubital vein: at rest before exercise, immediately after, after 30 min recovery, 24 h and 48 h after the tests. The magnitude of the acute inflammatory response to exercise was assessed by measuring plasma levels of polymorphonuclear elastase ([EL]), myeloperoxidase ([MPO]) and PGE2 ([PGE2]). Using two way analysis of variance, it appeared that only eccentric exercise significantly increased [EL] and DOMS, especially of the hamstring muscles. Furthermore, a significant decrease in eccentric peak torque of this muscle group only was observed on day 2 after eccentric work (- 21%; P < 0.002). Serum activity of creatine kinase and serum concentration of myoglobin increased significantly 24 and 48 h after both exercise tests. However, these variables reached significantly higher values following eccentric contractions 48 h after exercise. Mean [PGE2] in the two exercise modes remained unchanged over time and were practically equal at each time point. On the basis of these findings, we conclude that the magnitude of polymorphonuclear (PMN) activation, muscle damage, and DOMS are greater after eccentric than after concentric muscle

  10. Increased expression of stefin B in the nucleus of T98G astrocytoma cells delays caspase activation

    Directory of Open Access Journals (Sweden)

    Tao eSun

    2012-09-01

    Full Text Available Stefin B (cystatin B is an endogenous inhibitor of cysteine proteinases localized in the nucleus and the cytosol. Loss-of-function mutations in the stefin B gene (CSTB gene were reported in patients with Unverricht-Lundborg disease (EPM1. Our previous results showed that thymocytes isolated from stefin B-deficient mice are more sensitive to apoptosis induced by the protein kinase C inhibitor staurosporin (STS than the wild-type control cells. We have also shown that the increased expression of stefin B in the nucleus of T98G astrocytoma cells delayed cell cycle progression through the S phase. In the present study we examined if the nuclear or cytosolic functions of stefin B are responsible for the accelerated induction of apoptosis observed in the cells from stefin B-deficient mice. We have shown that the overexpression of stefin B in the nucleus, but not in the cytosol of astrocytoma T98G cells, delayed caspase-3 and-7 activation. Pretreatment of cells with the pan-caspase inhibitor z-Val-Ala-Asp(OMe-fluoromethylketone completely inhibited caspase activation, while treatment with the inhibitor of calpains- and papain-like cathepsins (2S,3S-trans-epoxysuccinyl-leucylamido-3-methyl-butane ethyl ester did not prevent caspase activation. We concluded that the delay of caspase activation in T98G cells overexpressing stefin B in the nucleus is independent of cathepsin inhibition.

  11. A theory of synchrony for active compartments with delays coupled through bulk diffusion

    Science.gov (United States)

    Xu, Bin; Bressloff, Paul C.

    2017-02-01

    We extend recent work on the analysis of synchronization in a pair of biochemical oscillators coupled by linear bulk diffusion, in order to explore the effects of discrete delays. More specifically, we consider two well-mixed, identical compartments located at either end of a bounded, one-dimensional domain. The compartments can exchange signaling molecules with the bulk domain, within which the signaling molecules undergo diffusion. The concentration of signaling molecules in each compartment is modeled by a delay differential equation (DDE), while the concentration in the bulk medium is modeled by a partial differential equation (PDE) for diffusion. Coupling in the resulting PDE-DDE system is via flux terms at the boundaries. Using linear stability analysis, numerical simulations and bifurcation analysis, we investigate the effect of diffusion on the onset of a supercritical Hopf bifurcation. The direction of the Hopf bifurcation is determined by numerical simulations and a winding number argument. Near a Hopf bifurcation point, we find that there are oscillations with two possible modes: in-phase and anti-phase. Moreover, the critical delay for oscillations to occur increases with the diffusion coefficient. Our numerical results suggest that the selection of the in-phase or anti-phase oscillation is sensitive to the diffusion coefficient, time delay and coupling strength. For slow diffusion and weak coupling both modes can coexist, while for fast diffusion and strong coupling, only one of the modes is dominant, depending on the explicit choice of DDE.

  12. Periodicity and global exponential stability of generalized Cohen-Grossberg neural networks with discontinuous activations and mixed delays.

    Science.gov (United States)

    Wang, Dongshu; Huang, Lihong

    2014-03-01

    In this paper, we investigate the periodic dynamical behaviors for a class of general Cohen-Grossberg neural networks with discontinuous right-hand sides, time-varying and distributed delays. By means of retarded differential inclusions theory and the fixed point theorem of multi-valued maps, the existence of periodic solutions for the neural networks is obtained. After that, we derive some sufficient conditions for the global exponential stability and convergence of the neural networks, in terms of nonsmooth analysis theory with generalized Lyapunov approach. Without assuming the boundedness (or the growth condition) and monotonicity of the discontinuous neuron activation functions, our results will also be valid. Moreover, our results extend previous works not only on discrete time-varying and distributed delayed neural networks with continuous or even Lipschitz continuous activations, but also on discrete time-varying and distributed delayed neural networks with discontinuous activations. We give some numerical examples to show the applicability and effectiveness of our main results.

  13. Rectified optical force on dark-state atoms

    Science.gov (United States)

    Korsunsky, E. A.; Kosachiov, D. V.

    1997-12-01

    We show that an imperfection of velocity-selective coherent population trapping (VSCPT) in three-level atoms excited by standing light waves causes a rectified force on cooled atoms. The rectified force as well as the cooling force are calculated both analytically and numerically for 0953-4075/30/24/010/img5 and cascade three-level systems. Combination of these forces with the VSCPT mechanism can lead to localization of very cold atoms in potential wells created by the rectified force. This effect should be taken into account in experiments with VSCPT in standing waves, and can be used for realizing superlattices of cold atoms, in particular, cold Rydberg atoms.

  14. Formal Verification of Full-Wave Rectifier: A Case Study

    CERN Document Server

    Lata, Kusum

    2009-01-01

    We present a case study of formal verification of full-wave rectifier for analog and mixed signal designs. We have used the Checkmate tool from CMU [1], which is a public domain formal verification tool for hybrid systems. Due to the restriction imposed by Checkmate it necessitates to make the changes in the Checkmate implementation to implement the complex and non-linear system. Full-wave rectifier has been implemented by using the Checkmate custom blocks and the Simulink blocks from MATLAB from Math works. After establishing the required changes in the Checkmate implementation we are able to efficiently verify the safety properties of the full-wave rectifier.

  15. Analytic capacity, rectifiability, menger curvature and the Cauchy integral

    CERN Document Server

    Pajot, Hervé

    2002-01-01

    Based on a graduate course given by the author at Yale University this book deals with complex analysis (analytic capacity), geometric measure theory (rectifiable and uniformly rectifiable sets) and harmonic analysis (boundedness of singular integral operators on Ahlfors-regular sets). In particular, these notes contain a description of Peter Jones' geometric traveling salesman theorem, the proof of the equivalence between uniform rectifiability and boundedness of the Cauchy operator on Ahlfors-regular sets, the complete proofs of the Denjoy conjecture and the Vitushkin conjecture (for the latter, only the Ahlfors-regular case) and a discussion of X. Tolsa's solution of the Painlevé problem.

  16. Modulation of Exciton Generation in Organic Active Planar pn Heterojunction: Toward Low Driving Voltage and High-Efficiency OLEDs Employing Conventional and Thermally Activated Delayed Fluorescent Emitters.

    Science.gov (United States)

    Chen, Dongcheng; Liu, Kunkun; Gan, Lin; Liu, Ming; Gao, Kuo; Xie, Gaozhan; Ma, Yuguang; Cao, Yong; Su, Shi-Jian

    2016-08-01

    Organic light-emitting diodes (OLEDs) combining low driving voltage and high efficiency are designed by employing conventional and thermally activated delayed fluorescence emitters through modulation of excitons generated at the planar p-n heterojunction region. To date, this approach enables the highest power efficiency for yellow-green emitting fluorescent OLEDs with a simplified structure.

  17. Delay discounting without decision-making: Medial prefrontal cortex and amygdala activations reflect immediacy processing and correlate with impulsivity and anxious-depressive traits

    Directory of Open Access Journals (Sweden)

    Vera eLudwig

    2015-10-01

    Full Text Available Humans value rewards less when these are delivered in the future as opposed to immediately, a phenomenon referred to as delay discounting. While delay discounting has been studied during the anticipation of rewards and in the context of intertemporal decision-making, little is known about its neural correlates in the outcome phase (during reward delivery and their relation to personality. Personality traits that have been associated with increased delay discounting include impulsivity and, potentially, anxious-depressive traits. Here we performed functional magnetic resonance imaging (fMRI in 72 healthy participants while they carried out a monetary incentive delay task with a delay manipulation. In sixty percent of the experimental trials, participants won rewards that differed in magnitude (0.05€, 0.50€ or 1€ and delay until delivery (immediately, 10 days, or 100 days. A factor analysis on questionnaires yielded two factors reflecting Impulsivity and Anxiety/Depression, which we used to examine potential relationships between personality and delay discounting. When winning a reward, medial prefrontal cortex (mPFC activation was higher for immediate compared to delayed rewards. Moreover, amygdala activation correlated with reward magnitude for immediate but not for delayed rewards. Amygdala activation to winning immediate rewards was higher in more impulsive participants, while mPFC activation to winning immediate rewards was higher in more anxious-depressed participants. Our results uncover neural correlates of delay discounting during reward delivery, and suggest that impulsivity and subclinical anxious-depressive traits are related to stronger neural responses for winning immediate relative to delayed rewards.

  18. Graphene Triangular Ballistic Rectifier: Fabrication and Characterisation

    Science.gov (United States)

    Auton, Gregory; Kumar, Roshan Krishna; Hill, Ernie; Song, Aimin

    2016-09-01

    It has been shown that graphene can demonstrate ballistic transport at room temperature. This opens up a range of practical applications that do not require graphene to have a band gap, which is one of the most significant challenges for its use in the electronics industry. Here, the very latest high mobility graphene (>100,000 cm2 V-1 s-1) fabrication techniques will be demonstrated so that one such device, called the triangular ballistic rectifier (TBR), can be characterised. The TBR is a four-terminal device with a triangular anti-dot at their intersection; two sides of the triangle are positioned and angled such that ballistic carriers from the two input electrodes are redirected like billiard balls to one of the two output contacts irrespective of the instantaneous polarity of the input. A responsivity of 2400 mV mW-1 is demonstrated at room temperature from a low-frequency input signal. The ballistic nature of the device is justified and explained in more detail with low-temperature measurements.

  19. Guaranteed Cost Active Fault-tolerant Control of Networked Control System with Packet Dropout and Transmission Delay

    Institute of Scientific and Technical Information of China (English)

    Xiao-Yuan Luo; Mei-Jie Shang; Cai-Lian Chen; Xin-Ping Guan

    2010-01-01

    The problem of guaranteed cost active fault-tolerant controller (AFTC) design for networked control systems (NCSs)with both packet dropout and transmission delay is studied in this paper.Considering the packet dropout and transmission delay,a piecewise constant controller is adopted.With a guaranteed cost function,optimal controllers whose number is equal to the number of actuators are designed,and the design process is formulated as a convex optimal problem that can be solved by existing software.The control strategy is proposed as follows:when actuator failures appear,the fault detection and isolation unit sends out the information to the controller choosing strategy,and then the optimal stabilizing controller with the smallest guaranteed cost value is chosen.Two illustrative examples are given to demonstrate the effectiveness of the proposed approach.By comparing with the existing methods,it can be seen that our method has a better performance.

  20. 2011 NOAA Ortho-rectified Mosaic of Casco Bay, Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2011 NOAA Ortho-rectified Mosaic of Yabucoa, Puerto Rico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2011 NOAA Ortho-rectified Mosaic of Searsport Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2009 NOAA Ortho-rectified Mosaic of Brunswick Georgia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2011 NOAA Ortho-rectified Mosaic of Galveston, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2011 NOAA Ortho-rectified Mosaic of Baltimore, Maryland

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2012 NOAA Ortho-rectified Color Mosaic of Richmond, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2011 NOAA Ortho-rectified Mosaic of Mayaquez, Puerto Rico

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. Thin-film semiconductor rectifier has improved properties

    Science.gov (United States)

    1966-01-01

    Cadmium selenide-zinc selenide film is used as a thin film semiconductor rectifier. The film is vapor-deposited in a controlled concentration gradient into a glass substrate to form the required junctions between vapor-deposited gold electrodes.

  9. Maximal rectification ratios for bi-segment thermal rectifiers

    CERN Document Server

    Shih, Tien-Mo; Guo, Ziquan; Liu, Guangcao; Merlitz, Holger; Pagni, Patrick J; Chen, Zhong

    2014-01-01

    We study bi-segment thermal rectifiers whose forward heat fluxes are greater than reverse counterparts. Presently, a shortcoming of thermal rectifiers is that the rectification ratio, namely the forward flux divided by the reverse flux, remains too small for practical applications. In this study, we have managed to discover and theoretically derive the ultimate limit of such ratios, which are validated by numerical simulations, experiments, and micro-scale Hamiltonian-oscillator analyses. For rectifiers whose thermal conductivities are linear with the temperature, this limit is simply a numerical value of 3. For those whose conductivities are nonlinear with temperatures, the maxima equal $\\kappa_{max}/\\kappa_{min}$, where the two extremes denote values of the solid segment materials that can be possibly found or fabricated within a reasonable temperature range on earth. Recommendations for manufacturing high-ratio rectifiers are also given with examples.

  10. Maximal rectification ratios for idealized bi-segment thermal rectifiers.

    Science.gov (United States)

    Shih, Tien-Mo; Gao, Zhaojing; Guo, Ziquan; Merlitz, Holger; Pagni, Patrick J; Chen, Zhong

    2015-08-04

    Thermal rectifiers whose forward heat fluxes are greater than reverse counterparts have been extensively studied. Here we have discovered, idealized, and derived the ultimate limit of such rectification ratios, which are partially validated by numerical simulations, experiments, and micro-scale Hamiltonian-oscillator analyses. For rectifiers whose thermal conductivities (κ) are linear with the temperature, this limit is simply a numerical value of 3. For those whose conductivities are nonlinear with temperatures, the maxima equal κmax/κmin, where two extremes denote values of the solid segment materials that can be possibly found or fabricated within a reasonable temperature range. Recommendations for manufacturing high-ratio rectifiers are also given with examples. Under idealized assumptions, these proposed rectification limits cannot be defied by any bi-segment thermal rectifiers.

  11. 2012 NOAA Ortho-rectified Color Mosaic of Bangor, Washington

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. Activation of mitochondrial ATP-sensitive potassium channels delays ischemia-induced cellular uncoupling in rat heart

    Institute of Scientific and Technical Information of China (English)

    Yue-liangSHEN; Ying-yingCHEN; Xun-dongWU; IainCBRUCE; QiangXIA

    2004-01-01

    AIM: To test the hypothesis that cellular uncoupling induced by myocardial ischemia is mediated by activation of mitochondrial ATP-sensitive potassium channels (mitoKATP). METHODS: Rat hearts were perfused on a Langendorff apparatus and subjected to 40-min ischemia followed by 30-min reperfusion (I/R). Changes in cellular coupling were monitored by measuring whole-tissue resistance. RESULTS: (1) In hearts subjected to I/R, the onset of uncoupling started at (13.3± 1.0) min of ischemia; (2) Ischemic preconditioning (IPC) delayed the onset of uncoupling until (22.7±1.3) min. Blocking mitoKATP channels with 5-hydroxydecanoate (5-HD) before the IPC abolishedthe uncoupling delay [(12.6±1.6)min]; (3) Calcium preconditioning (CPC) had the same effect as IPC. And this effect was reversed by blocking the mitoKATP channel again. In the CPC group the onset of uncoupling occurred after (20.6±1.3) min, and this was canceled by 5-HD [(13.6±0.8) min]; (4) In hearts pretreated with the specific mitoKATP channel opener diazoxide before sustained ischemia, the onset was delayed to (18.4±1.4) min; (5) 5-HD canceled the protective effects of diazoxide (12.6±1.0) min; and both the L-type Ca2+ channel inhibitor verapamiland the free radical scavenger N-(2-mercaptopropionyl)glycine, reduced the extended onset time induced by diazoxide[to (13.3±1.8) min and (13.4±2.1) min, respectively]. CONCLUSION: IPC and CPC delay the onset of cellular uncoupling induced by acute ischemia in rat heart, and the underlying mechanism involves activation of the mitoKATP channels.

  13. Wireless power transmission for biomedical implants: The role of near-zero threshold CMOS rectifiers.

    Science.gov (United States)

    Mohammadi, Ali; Redoute, Jean-Michel; Yuce, Mehmet R

    2015-01-01

    Biomedical implants require an electronic power conditioning circuitry to provide a stable electrical power supply. The efficiency of wireless power transmission is strongly dependent on the power conditioning circuitry specifically the rectifier. A cross-connected CMOS bridge rectifier is implemented to demonstrate the impact of thresholds of rectifiers on wireless power transfer. The performance of the proposed rectifier is experimentally compared with a conventional Schottky diode full wave rectifier over 9 cm distance of air and tissue medium between the transmitter and receiver. The output voltage generated by the CMOS rectifier across a 1 KΩ resistive load is around twice as much as the Schottky rectifier.

  14. Scalar Controlled Boost PWM Rectifier for Micro Wind Energy Systems

    Directory of Open Access Journals (Sweden)

    J. Chelladurai

    2015-05-01

    Full Text Available Uses of Permanent Magnet Synchronous Generators (PMSG are increasing in variable speed micro-Wind Energy Conversion Systems (WECS. In stand-alone or grid-connected Micro-WECS, extraction of maximum power is vital. To extract maximum power output and to obtain a constant DC bus voltage from variable magnitude and variable frequency voltage output of PMSG and generally a two stage scheme namely i conventional diode bridge rectifier and ii DC-DC Boost/Buck/Buck-Boost converters are used. In this study, a single stage Scalar Controlled PWM (SCPWM Boost Rectifier is proposed in order to minimize the current harmonics and to improve the power factor on source side. The modeling and simulation of PMSG based wind generator and SCPWM Boost rectifier was developed in MATLAB. The harmonic content in the input current waveform of the proposed SCPWM rectifier is compared with the conventional three-phase bridge rectifier. The Simulation results show the effectiveness of the PWM Boost rectifier in terms of effective utilization of source, improved efficiency and harmonic mitigation for PMSG based Wind Generator. Simulation results demonstrate the effectiveness of the proposed system in reducing the current and voltage THD on source side.

  15. 新疆维吾尔族老年人群延迟整流型钾离子通道 KCNE1(G38S)基因多态性与心房颤动的相关性研究%Relationship between delayed rectifier potassium channel KCNE1 (G38S) gene polymorphism and atrial fibrillation in elderly Uygur population in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    郭玉君; 艾力曼·马合木提; 王坤

    2014-01-01

    目的:探讨新疆维吾尔族老年人群延迟整流型钾离子通道KCNE1( G38S)基因多态性与心房颤动( AF)的相关性。方法收集新疆地区维吾尔族AF人群( AF组)和非AF人群(对照组)各70例的外周血样标本,提取 DNA,采用等位基因聚合酶链反应(PCR⁃RFLP)的方法鉴定KCNE1(G38S)的基因型及等位基因分布。采用Logistic 回归分析各种因素与房颤的相关性。结果 KCNE1基因 G38S 位点 AA、AG、GG 基因型频率在AF组分别为17�14%、27�14%、55�71%。在对照组分别为24�29%、50%、25�71%。2组基因型分布差异具有统计学意义( P<0�05),且AF组G等位基因频率明显高于对照组( P<0�05)。 Logistic回归分析结果显示KCNE1( G38S) GG基因型与维吾尔族人群AF的发生相关( P<0�05)。结论新疆地区维吾尔族人群AF的发生与KCNE1( G38S)基因多态性相关。 G38S位点多态性可能是维吾尔族AF患者的独立危险因素之一。%Objective To investigate the correlation between delayed rectifier potassium channel KCNE1 ( G38S) and atrial fibrillation( AF) . Methods Seventy elderly Uygur patients with AF ( AF group) and seventy elderly Uygur pa⁃tients without AF ( non⁃AF group) were enrolled in this study. Peripheral blood sample specimens were collected and DNA was extracted from all subjects. KCNE1 ( G38S) genotypes and allelic distribution were identificated with the polymerase chain reaction⁃extinction enzymes fragment length polymorphism (PCR⁃RFLP). The risk factors of AF were analyzed using Logistic regression analysis. Results The frequency of AA, AG and GG genotype was 17�14%, 27�14%, 55�71% at KCNE1 gene( G38S site) in AF group, compared with 24�29%, 50% and 25�71% in the control group( P<0�05) , and G allele frequency was higher in AF group than that in the control group ( P<0�05);Logistic regression analysis showed that KCNE1 ( G

  16. On utilizing delayed feedback for active-multimode vibration control of cantilever beams

    Science.gov (United States)

    Alhazza, Khaled A.; Nayfeh, Ali H.; Daqaq, Mohammed F.

    2009-01-01

    We present a single-input single-output multimode delayed-feedback control methodology to mitigate the free vibrations of a flexible cantilever beam. For the purpose of controller design and stability analysis, we consider a reduced-order model consisting of the first n vibration modes. The temporal variation of these modes is represented by a set of nonlinearly coupled ordinary-differential equations that capture the evolving dynamics of the beam. Considering a linearized version of these equations, we derive a set of analytical conditions that are solved numerically to assess the stability of the closed-loop system. To verify these conditions, we characterize the stability boundaries using the first two vibration modes and compare them to damping contours obtained by long-time integration of the full nonlinear equations of motion. Simulations show excellent agreement between both approaches. We analyze the effect of the size and location of the piezoelectric patch and the location of the sensor on the stability of the response. We show that the stability boundaries are highly dependent on these parameters. Finally, we implement the controller on a cantilever beam for different controller gain-delay combinations and assess the performance using time histories of the beam response. Numerical simulations clearly demonstrate the controller ability to mitigate vibrations emanating from multiple modes simultaneously.

  17. Transfer function models to quantify the delay between air and ground temperatures in thawed active layers

    Directory of Open Access Journals (Sweden)

    E. Zenklusen Mutter

    2011-10-01

    Full Text Available Air temperatures influence ground temperatures with a certain delay, which increases with depth. Borehole temperatures measured at 0.5 m depth in Alpine permafrost and air temperatures measured at or near the boreholes have been used to model this dependency. Statistical transfer function models have been fitted to the daily difference series of air and ground temperatures measured at seven different permafrost sites in the Swiss Alps.

    The relation between air and ground temperature is influenced by various factors such as ground surface cover, snow depth, water or ground ice content. To avoid complications induced by the insulating properties of the snow cover and by phase changes in the ground, only the mostly snow-free summer period when the ground at 0.5 m depth is thawed has been considered here. All summers from 2006 to 2009 have been analysed, with the main focus on summer 2006.

    The results reveal that in summer 2006 daily air temperature changes influence ground temperatures at 0.5 m depth with a delay ranging from one to six days, depending on the site. The fastest response times are found for a very coarse grained, blocky rock glacier site whereas slower response times are found for blocky scree slopes with smaller grain sizes.

  18. Multistability of neural networks with discontinuous non-monotonic piecewise linear activation functions and time-varying delays.

    Science.gov (United States)

    Nie, Xiaobing; Zheng, Wei Xing

    2015-05-01

    This paper is concerned with the problem of coexistence and dynamical behaviors of multiple equilibrium points for neural networks with discontinuous non-monotonic piecewise linear activation functions and time-varying delays. The fixed point theorem and other analytical tools are used to develop certain sufficient conditions that ensure that the n-dimensional discontinuous neural networks with time-varying delays can have at least 5(n) equilibrium points, 3(n) of which are locally stable and the others are unstable. The importance of the derived results is that it reveals that the discontinuous neural networks can have greater storage capacity than the continuous ones. Moreover, different from the existing results on multistability of neural networks with discontinuous activation functions, the 3(n) locally stable equilibrium points obtained in this paper are located in not only saturated regions, but also unsaturated regions, due to the non-monotonic structure of discontinuous activation functions. A numerical simulation study is conducted to illustrate and support the derived theoretical results.

  19. Application of Time Delay Consideration on Bridge Vibration Control Method with Active Tendons

    Directory of Open Access Journals (Sweden)

    Lezin Seba MINSILI

    2010-12-01

    Full Text Available For many years bridge structures have been designed or constructed as passive structures that rely on their mass and solidity to resist external forces, while being incapable of adapting to the dynamics of an ever-changing environment. When the rigidity assumption is not met in particular for high-rise structures like bridge towers, a proper dynamic model should be established and conclusions made on the differential vibration of the tower when it is investigated out of the bridge system. The present work outlines a vibration control method by tendons on the tower of cable supported structures considering time delay effects, based on the discrete-time Linearization of the Feedback Gain Matrix. The efficiency of this vibration control method first proposed on the design process of a local bridge in Cameroon, is more compatible to the control of civil structures and is of great interest in accordance with simulation results.

  20. Remote electrical stimulation by means of implanted rectifiers.

    Directory of Open Access Journals (Sweden)

    Antoni Ivorra

    Full Text Available Miniaturization of active implantable medical devices is currently compromised by the available means for electrically powering them. Most common energy supply techniques for implants--batteries and inductive couplers--comprise bulky parts which, in most cases, are significantly larger than the circuitry they feed. Here, for overcoming such miniaturization bottleneck in the case of implants for electrical stimulation, it is proposed to make those implants act as rectifiers of high frequency bursts supplied by remote electrodes. In this way, low frequency currents will be generated locally around the implant and these low frequency currents will perform stimulation of excitable tissues whereas the high frequency currents will cause only innocuous heating. The present study numerically demonstrates that low frequency currents capable of stimulation can be produced by a miniature device behaving as a diode when high frequency currents, neither capable of thermal damage nor of stimulation, flow through the tissue where the device is implanted. Moreover, experimental evidence is provided by an in vivo proof of concept model consisting of an anesthetized earthworm in which a commercial diode was implanted. With currently available microelectronic techniques, very thin stimulation capsules (diameter <500 µm deliverable by injection are easily conceivable.

  1. A metamaterial electromagnetic energy rectifying surface with high harvesting efficiency

    Science.gov (United States)

    Duan, Xin; Chen, Xing; Zhou, Lin

    2016-12-01

    A novel metamaterial rectifying surface (MRS) for electromagnetic energy capture and rectification with high harvesting efficiency is presented. It is fabricated on a three-layer printed circuit board, which comprises an array of periodic metamaterial particles in the shape of mirrored split rings, a metal ground, and integrated rectifiers employing Schottky diodes. Perfect impedance matching is engineered at two interfaces, i.e. one between free space and the surface, and the other between the metamaterial particles and the rectifiers, which are connected through optimally positioned vias. Therefore, the incident electromagnetic power is captured with almost no reflection by the metamaterial particles, then channeled maximally to the rectifiers, and finally converted to direct current efficiently. Moreover, the rectifiers are behind the metal ground, avoiding the disturbance of high power incident electromagnetic waves. Such a MRS working at 2.45 GHz is designed, manufactured and measured, achieving a harvesting efficiency up to 66.9% under an incident power density of 5 mW/cm2, compared with a simulated efficiency of 72.9%. This high harvesting efficiency makes the proposed MRS an effective receiving device in practical microwave power transmission applications.

  2. Enhanced rectifying response from metal-insulator-insulator-metal junctions

    Science.gov (United States)

    Maraghechi, P.; Foroughi-Abari, A.; Cadien, K.; Elezzabi, A. Y.

    2011-12-01

    We present on a metal-insulator-insulator-metal quantum electronic tunneling devices suitable for high speed rectifiers. Through the introduction of double oxide layer between similar metallic electrodes, a cascaded potential barrier is formed which alters the electron tunneling mechanism at forward versus the reverse bias. The cascaded potential barrier engineering manifests itself in both a highly nonlinear and asymmetric I-V junction characteristic. It is envisioned that high speed rectifiers and mixers having extraordinary nonlinearity can be realized through the incorporation of the cascaded potential barrier architecture and dissimilar metallic electrodes.

  3. Three-phase bridge rectifiers with freewheeling diodes

    CERN Document Server

    Hausler, M

    1973-01-01

    Freewheeling diodes are used in controlled rectifiers working in one quadrant only in order to reduce the reactive power and the d.c.- voltage ripple. In addition the freewheeling diodes allow a higher d.c.-current at low d.c.-voltages. The mean value of the freewheeling current depends on the d.c.-current, the load, and the stray-reactance of the rectifier transformer. This paper describes how the freewheeling current can be determined with these parameters. Results for some typical cases are shown in diagrams. (2 refs).

  4. The Effects of Activating the Money Concept on Perseverance and the Preference for Delayed Gratification in Children.

    Science.gov (United States)

    Trzcińska, Agata; Sekścińska, Katarzyna

    2016-01-01

    The psychological model of thinking about money assumes that implicit reminders of money lead to self-sufficient motivation. Previous research has demonstrated that children react to money in similar ways to adults. The priming of young children with money related concepts or images has negatively affected their social behavior and social preferences, leading them to make more individualist and less pro-social choices and be less willing to help others. The aim of this research was to investigate the positive influence of money activation on children's behavior. The participants were 6-8 year old children who do not yet fully understand the instrumental function of money due to their young age. Two experimental studies were performed, the first of which analyzed the effect of perseverance and performance on a challenging task and the second investigated preferences with respect to delaying gratification. Sixty-one children aged 6 took part in the first study and forty-six scout camp participants 6-8 years of age were involved in the second experiment. The results support the hypotheses concerning the effects of money activation stating that (1) money activation influences children's perseverance and effectiveness in difficult individual tasks, and that (2) it increases children's preferences for delayed gratification. These results suggest that money has a symbolic power which may exert both positive and negative effects on children's behavior. Since children between the ages of 6 and 8 do not understand the instrumental function of money fully, certain symbolic meanings of money may have been responsible for the money priming effects. The findings suggest that the symbolic function of money is more primal than its instrumental function and that it probably develops at an earlier stage in life.

  5. Universal Voltage Conveyor and Current Conveyor in Fast Full-Wave Rectifier

    Directory of Open Access Journals (Sweden)

    Josef Burian

    2012-12-01

    Full Text Available This paper deals about the design of a fast voltage-mode full-wave rectifier, where universal voltage conveyor and second-generation current conveyor are used as active elements. Thanks to the active elements, the input and output impedance of the non-linear circuit is infinitely high respectively zero in theory. For the rectification only two diodes and three resistors are required as passive elements. The performance of the circuit is shown on experimental measurement results showing the dynamic range, time response, frequency dependent DC transient value and RMS error for different values of input voltage amplitudes.

  6. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  7. Multistability of delayed complex-valued recurrent neural networks with discontinuous real-imaginary-type activation functions

    Science.gov (United States)

    Huang, Yu-Jiao; Hu, Hai-Gen

    2015-12-01

    In this paper, the multistability issue is discussed for delayed complex-valued recurrent neural networks with discontinuous real-imaginary-type activation functions. Based on a fixed theorem and stability definition, sufficient criteria are established for the existence and stability of multiple equilibria of complex-valued recurrent neural networks. The number of stable equilibria is larger than that of real-valued recurrent neural networks, which can be used to achieve high-capacity associative memories. One numerical example is provided to show the effectiveness and superiority of the presented results. Project supported by the National Natural Science Foundation of China (Grant Nos. 61374094 and 61503338) and the Natural Science Foundation of Zhejiang Province, China (Grant No. LQ15F030005).

  8. Highly Efficient Nondoped Organic Light Emitting Diodes Based on Thermally Activated Delayed Fluorescence Emitter with Quantum-Well Structure.

    Science.gov (United States)

    Meng, Lingqiang; Wang, Hui; Wei, Xiaofang; Liu, Jianjun; Chen, Yongzhen; Kong, Xiangbin; Lv, Xiaopeng; Wang, Pengfei; Wang, Ying

    2016-08-17

    Highly efficiency nondoped thermally activated delayed fluorescence (TADF) organic light emitting diodes (OLEDs) with multiquantum wells structure were demonstrated. By using an emitting layer with seven quantum wells, the nondoped TADF OLEDs exhibit high efficiency with EQE of 22.6%, a current efficiency of 69 cd/A, and a power efficiency of 50 lm/W, which are higher than those of the conventional doped OLED and among the best of the TADF OLEDs. The high performance of the devices can be ascribed to effective confinement of the charges and excitons in the emission layer by the quantum well structure. The emission layer with multiquantum well structure is demonstrated to be cost effective for highly efficient nondoped TADF OLEDs and holds great potential for organic electronics.

  9. Different Types of Projective Synchronization in a Class of Time-Delayed Chaotic Systems Using Active Control Approach

    Institute of Scientific and Technical Information of China (English)

    FENG Cun-Fang; WANG Ying-Hai

    2011-01-01

    We study different types of projective synchronization (projective-anticipating, projective, and projectivelag synchronization) in a class of time-delayed chaotic systems related to optical bistable or hybrid optical bistable devices.We relax some limitations of previous work, where the scaling factor a can not be any desired value.In this paper, we achieve projective-anticipating, projective, and projective-lag synchronization without the limitation of α.A suitable controller is chosen using active control approach.Based on the Lyapunov stability theory, we derive the sutficient stability condition through theoretical analysis.The analytical results are validated by the numerical simulations using Ikeda model and Mackey-Glass model.

  10. Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state.

    Science.gov (United States)

    Bergmann, Larissa; Hedley, Gordon J; Baumann, Thomas; Bräse, Stefan; Samuel, Ifor D W

    2016-01-01

    Intersystem crossing in thermally activated delayed fluorescence (TADF) materials is an important process that controls the rate at which singlet states convert to triplets; however, measuring this directly in TADF materials is difficult. TADF is a significant emerging technology that enables the harvesting of triplets as well as singlet excited states for emission in organic light emitting diodes. We have observed the picosecond time-resolved photoluminescence of a highly luminescent, neutral copper(I) complex in the solid state that shows TADF. The time constant of intersystem crossing is measured to be 27 picoseconds. Subsequent overall reverse intersystem crossing is slow, leading to population equilibration and TADF with an average lifetime of 11.5 microseconds. These first measurements of intersystem crossing in the solid state in this class of mononuclear copper(I) complexes give a better understanding of the excited-state processes and mechanisms that ensure efficient TADF.

  11. In-Flight Active Wave Cancelation with Delayed-x-LMS Control Algorithm in a Laminar Boundary Layer

    Science.gov (United States)

    Simon, Bernhard; Fabbiane, Nicolo; Nemitz, Timotheus; Bagheri, Shervin; Henningson, Dan; Grundmann, Sven

    2016-11-01

    This manuscript demonstrates the first successful application of the delayed-x-LMS (dxLMS) control algorithm for TS-wave cancelation. Active wave cancelation of two-dimensional broad-band Tollmien-Schlichting (TS) disturbances is performed with a single DBD plasma actuator. The experiments are conducted in flight on the pressure side of a laminar flow wing glove, mounted on a manned glider. The stability properties of the controller are investigated in detail with experimental flight data, DNS and stability analysis of the boundary layer. Finally, a model-free approach for dxLMS operation is introduced to operate the controller as a "black box" system, which automatically adjusts the controller settings based on a group speed measurement of the disturbance wave packets. The modified dxLMS controller is operated without a model and is able to adapt to varying conditions that may occur during flight in atmosphere. DFG No.GR3524/4-1.

  12. In-flight active wave cancelation with delayed-x-LMS control algorithm in a laminar boundary layer

    Science.gov (United States)

    Simon, Bernhard; Fabbiane, Nicolò; Nemitz, Timotheus; Bagheri, Shervin; Henningson, Dan S.; Grundmann, Sven

    2016-10-01

    This manuscript demonstrates the first successful application of the delayed-x-LMS (dxLMS) control algorithm for TS-wave cancelation. Active wave cancelation of two-dimensional broadband Tollmien-Schlichting (TS) disturbances is performed with a single DBD plasma actuator. The experiments are conducted in flight on the pressure side of a laminar flow wing glove, mounted on a manned glider. The stability properties of the controller are investigated in detail with experimental flight data, DNS and stability analysis of the boundary layer. Finally, a model-free approach for dxLMS operation is introduced to operate the controller as a `black-box' system, which automatically adjusts the controller settings based on a group speed measurement of the disturbance wave packets. The modified dxLMS controller is operated without a model and is able to adapt to varying conditions that may occur during flight in atmosphere.

  13. Design of active disturbance rejection internal model control strategy for SISO system with time delay process

    Institute of Scientific and Technical Information of China (English)

    JIN Qi-bing; LIU Li-ye

    2015-01-01

    A novel control scheme of active disturbance rejection internal model control (ADRIMC) is proposed to improve the anti-interference ability and robustness for the dead-time process. The active anti-interference concept is introduced into the internal model control (IMC) by analyzing the relationship between IMC and disturbance observer control (DOB). Further, a design process of disturbance filter is presented to realize the active anti-interference ability for ADRIMC scheme. The disturbance filter is used to estimate an equivalent disturbance consisting of both external disturbances and internal disturbances caused by model mismatches. Simulation results demonstrate that the proposed method possesses a good disturbance rejection performance, though losing some partial dynamic performance. In other words, the proposed method shows a tradeoff between the dynamic performance and the system robust.

  14. Kinesiology Tape does not Affect Serum Creatine Kinase Level and Quadriceps Activity during Recovery from Delayed-Onset Muscle Soreness

    Directory of Open Access Journals (Sweden)

    Naoko Aminaka

    2017-01-01

    Full Text Available Background: Delayed-onset muscle soreness (DOMS causes muscle damage and edema that can hinder performance and increase risks for secondary injuries. Kinesiology Tape (KT may be an effective modality for aiding in recovery, however, no study has investigated the effects of KT on the physiological biomarkers such as serum creatine kinase (CK level, concurrently with measures of performance and function, during recovery from DOMS. Objective: Investigate the effects of KT on serum CK level, electromyographic (EMG activity of the quadriceps muscles, and performances of countermovement jump (CMJ and triple single-leg hop for distance (HopD during recovery from DOMS. Method: Fifty-eight healthy college-age participants were randomly assigned to KT (n=15, placebo (n=19, and control (n=24 groups. Serum CK level and quadriceps EMG activity and performance during CMJ and HopD were collected at baseline, immediately after repetitive eccentric quadriceps exercise, 48 hours, and 72 hours post-exercise. The EMG recording of rectus femoris, vastus medialis, and vastus lateralis during the CMJ and HopD were normalized to the baseline maximum voluntary isometric contraction. Results: A significant main effect of time on the serum CK level, EMG activity, and performance (p0.05. Conclusion: Taping interventions did not improve the serum CK level or muscle activity and performance during recovery from DOMS. Kinesiology tape may not be the first choice of method for enhancing recovery from DOMS in otherwise healthy individuals.

  15. Effect of ranitidine on postoperative suppression of natural killer cell activity and delayed hypersensitivity

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørgen; Pedersen, B K; Moesgaard, F;

    1989-01-01

    hypersensitivity (DTH) antigens, and blood drawn immediately before and 24 hours after skin incision was analyzed for spontaneous and in vitro stimulated (IL-2, IFN-alpha or indomethacin) natural killer (NK) cell activity and PHA and PPD-stimulated lymphocyte proliferation. Lymphocyte subsets (helper......-cell activity (p less than 0.02). Postoperative decrease in helper/inducer-T cell numbers was not significantly lessened (p = 0.07), and ranitidine did not influence the levels of suppressor-T cells. PHA and PPD responses in peripheral blood mononuclear cells were unaltered. The results may suggest potential...

  16. Effect of Calcium-Activated Chloride Current Blockade on the Delayed Afterdepolarizations. Simulation Study

    Science.gov (United States)

    2007-11-02

    dog and rabbit ventricular cells [4, 6]. The ionic nature of Iti is still subject to debate. Several authors propose two ionic currents to contribute to...activated Cl currents in the heart: a computer model. Computers in Cardiology 1999; 26: 109-112. Julio Gomis-Tena Dolz U.P.V. Departamento de Ingeniería

  17. Gate-controlled rectifying behavior in C70@SWNT networks.

    Science.gov (United States)

    Guo, Ao; Fu, Yunyi; Liu, Jia; Guan, Lunhui; Shi, Zujin; Gu, Zhennan; Huang, Ru; Zhang, Xing

    2006-05-25

    We report the gate-controlled rectification behavior in C(70)@SWNT networks at room temperature in air. The electrical transport characteristics can be fitted well with the conventional Schottky diode model. The origin of the rectifying behavior in fullerene peapod networks device is qualitatively discussed. This paper demonstrates a strategy for diode fabrication based on peapod networks.

  18. 35 GHz integrated circuit rectifying antenna with 33 percent efficiency

    Science.gov (United States)

    Yoo, T.-W.; Chang, K.

    1991-01-01

    A 35 GHz integrated circuit rectifying antenna (rectenna) has been developed using a microstrip dipole antenna and beam-lead mixer diode. Greater than 33 percent conversion efficiency has been achieved. The circuit should have applications in microwave/millimeter-wave power transmission and detection.

  19. Pulse-Width Control in Ladder Structure Four-Phase Rectifier for AC-Electromotive

    Science.gov (United States)

    Ivanov, V. V.; Myatez, S. V.; Langeman, E. G.; Schurov, N. I.

    2016-04-01

    Based on these studies the ways of power factor of the single-phase rectifiers operating in a single-phase AC network improving are suggested. The ladder four-phase rectifier is offered as a technical mean using a pulse-width method of controlling the rectified voltage. The pulse-width control efficiency as a way of the power factor rectifier with a ladder structure for AC electromotive improving is evaluated.

  20. Effect of activated charcoal on the pharmacokinetics of pholcodine, with special reference to delayed charcoal ingestion.

    Science.gov (United States)

    Laine, K; Kivistö, K T; Ojala-Karlsson, P; Neuvonen, P J

    1997-02-01

    We conducted a randomized study with four parallel groups to investigate the effect of single and multiple doses of activated charcoal on the absorption and elimination of pholcodine administered in a cough syrup. The first group received 100 mg of pholcodine on an empty stomach with water only (control); the second group took 25 g of activated charcoal immediately after pholcodine; the third group received 25 g of activated charcoal 2 h and the fourth group 5 h after ingestion of the 100-mg dose of pholcodine. In addition, the fourth group received multiple doses (10 g each) of charcoal every 12 h for 84 h. Blood samples were collected for 96 h and urine for 72 h. Pholcodine concentrations were measured by high-performance liquid chromatography. A significant reduction in absorption was found when charcoal was administered immediately after pholcodine; the AUC0-96h was reduced by 91% (p pholcodine excreted into urine by 85% (p pholcodine, the AUC0-96h was reduced by 26% (p = 0.002), the Cmax by 23% (p = NS), and the urinary excretion by 28% (p = 0.004). When administered 5 h after pholcodine, charcoal produced only a 17% reduction in the AUC0-96h (p = 0.06), but reduced the further absorption of pholcodine still present in the gastrointestinal tract at the time of charcoal administration, as measured by AUC5-96h (p = 0.006). Repeated administration of charcoal failed to accelerate the elimination of pholcodine. We conclude that activated charcoal is effective in preventing the absorption of pholcodine, and its administration can be beneficial even several hours after pholcodine ingestion.

  1. An inhibition of p38 mitogen activated protein kinase delays the platelet storage lesion.

    Directory of Open Access Journals (Sweden)

    Andrey Skripchenko

    Full Text Available BACKGROUND AND OBJECTIVES: Platelets during storage undergo diverse alterations collectively known as the platelet storage lesion, including metabolic, morphological, functional and structural changes. Some changes correlate with activation of p38 mitogen activated protein kinase (p38 MAPK. Another MAPK, extracellular signal-related kinase (ERK, is involved in PLT activation. The aim of this study was to compare the properties of platelets stored in plasma in the presence or absence of p38 and ERK MAPK inhibitors. MATERIALS AND METHODS: A single Trima apheresis platelet unit (n = 12 was aliquoted into five CLX storage bags. Two aliquots were continuously agitated with or without MAPK inhibitors. Two aliquots were subjected to 48 hours of interruption of agitation with or without MAPK inhibitors. One aliquot contained the same amount of solvent vehicle used to deliver the inhibitor. Platelets were stored at 20-24°C for 7 days and sampled on Days 1, 4, and 7 for 18 in vitro parameters. RESULTS: Inhibition of p38 MAPK by VX-702 leads to better maintenance of all platelet in vitro storage parameters including platelet mitochondrial function. Accelerated by interruption of agitation, the platelet storage lesion of units stored with VX-702 was diminished to that of platelets stored with continuous agitation. Inhibition of ERK MAPK did not ameliorate decrements in any in vitro platelet properties. CONCLUSION: Signaling through p38 MAPK, but not ERK, is associated with platelet deterioration during storage.

  2. MPC-SVM method for Vienna rectifier with PMSG used in Wind Turbine Systems

    DEFF Research Database (Denmark)

    Lee, June-Seok; Bak, Yeongsu; Lee, Kyo-Beum

    2016-01-01

    Using a Vienna rectifier as the machine-side rectifier of back-to-back converter is advantageous in terms of size and cost compared to three-level topologies and for this reason, the Vienna rectifier has been used in Wind Turbine Systems (WTS). This paper proposes a Model Predictive Control (MPC)...

  3. Robust and reliable rectifier based on electronic inductor with improved performance

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole

    2014-01-01

    Reliability of a power converter depends on voltage and current stresses seen by power semiconductor devices during transient and steady state operation of the power converter. Electronic smoothing inductor (ESI) is an attractive circuit topology to improve power factor and to reduce the total...... of the rectifier, peak to peak voltage ripples to the front end of the inverter reduces significantly by the ESI, and it increases lifetime of the capacitor connected at the output and also reduces the voltage stress of the active power semiconductors of the inverter if any connected to the output. In this paper...

  4. Separation by column chromatography of cells active in delayed-onset hypersensitivities.

    Science.gov (United States)

    Godfrey, H P; Gell, P G

    1976-01-01

    Lymph node cells from guinea-pigs contact sensitive to 1-thiocyamo-2,4-dinitrobenzene have been fractionated by affinity chromatography over modified polyacrylamide beads. Cells mediating lymphokine release in response to active sensitizer were depleted only by chromatography over dinitrophyenyl (DNP) containing substrates and could be specifically eluted with DNP-glycine. DNP rosette-forming cells (RFC) were equally well depleted by chromatography using either DNP or trinitrophenyl containing materials but could not be eluted from the columns by DNP-glycine. While the antigen receptors of cells mediating the release of macrophage agglutination factor in response to DNP-containing antigens and of DNP-RFC were found to be hapten-specific, their specificity was shown to differ using chromatography over trinitrophenyl containing polyacrylamide. PMID:776818

  5. A new pH-sensitive rectifying potassium channel in mitochondria from the embryonic rat hippocampus.

    Science.gov (United States)

    Kajma, Anna; Szewczyk, Adam

    2012-10-01

    Patch-clamp single-channel studies on mitochondria isolated from embryonic rat hippocampus revealed the presence of two different potassium ion channels: a large-conductance (288±4pS) calcium-activated potassium channel and second potassium channel with outwardly rectifying activity under symmetric conditions (150/150mM KCl). At positive voltages, this channel displayed a conductance of 67.84pS and a strong voltage dependence at holding potentials from -80mV to +80mV. The open probability was higher at positive than at negative voltages. Patch-clamp studies at the mitoplast-attached mode showed that the channel was not sensitive to activators and inhibitors of mitochondrial potassium channels but was regulated by pH. Moreover, we demonstrated that the channel activity was not affected by the application of lidocaine, an inhibitor of two-pore domain potassium channels, or by tertiapin, an inhibitor of inwardly rectifying potassium channels. In summary, based on the single-channel recordings, we characterised for the first time mitochondrial pH-sensitive ion channel that is selective for cations, permeable to potassium ions, displays voltage sensitivity and does not correspond to any previously described potassium ion channels in the inner mitochondrial membrane. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).

  6. Electroacupuncture Delays Hypertension Development through Enhancing NO/NOS Activity in Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Hye Suk Hwang

    2011-01-01

    Full Text Available Using spontaneously hypertensive rats (SHR, this study investigated whether electroacupuncture (EA could reduce early stage hypertension by examining nitric oxide (NO levels in plasma and nitric oxide synthase (NOS levels in the mesenteric resistance artery. EA was applied to the acupuncture point Governor Vessel 20 (GV20 or to a non-acupuncture point in the tail twice weekly for 3 weeks under anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY rats, blood pressure was determined the day after EA treatment by the tail-cuff method. We measured plasma NO concentration, and evaluated endothelial NO syntheses (eNOS and neuronal NOS (nNOS protein expression in the mesenteric artery. Systolic blood pressure (SBP and diastolic blood pressure (DBP were lower after 3 weeks of GV20 treatment than EA at non-acupuncture point and no treatment control in SHR. nNOS expression by EA was significantly different between both WKY and no treatment SHR control, and EA at GV20 in SHR. eNOS expression was significantly high in EA at GV 20 compared with no treatment control. In conclusion, EA could attenuate the blood pressure elevation of SHR, along with enhancing NO/NOS activity in the mesenteric artery in SHR.

  7. Bioturbation delays attenuation of DDT by clean sediment cap but promotes sequestration by thin-layered activated carbon.

    Science.gov (United States)

    Lin, Diana; Cho, Yeo-Myoung; Werner, David; Luthy, Richard G

    2014-01-21

    The effects of bioturbation on the performance of attenuation by sediment deposition and activated carbon to reduce risks from DDT-contaminated sediment were assessed for DDT sediment-water flux, biouptake, and passive sampler (PE) uptake in microcosm experiments with a freshwater worm, Lumbriculus variegatus. A thin-layer of clean sediment (0.5 cm) did not reduce the DDT flux when bioturbation was present, while a thin (0.3 cm) AC cap was still capable of reducing the DDT flux by 94%. Bioturbation promoted AC sequestration by reducing the 28-day DDT biouptake (66%) and DDT uptake into PE (>99%) compared to controls. Bioturbation further promoted AC-sediment contact by mixing AC particles into underlying sediment layers, reducing PE uptake (55%) in sediment compared to the AC cap without bioturbation. To account for the observed effects from bioturbation, a mass transfer model together with a biodynamic model were developed to simulate DDT flux and biouptake, respectively, and models confirmed experimental results. Both experimental measurements and modeling predictions imply that thin-layer activated carbon placement on sediment is effective in reducing the risks from contaminated sediments in the presence of bioturbation, while natural attenuation process by clean sediment deposition may be delayed by bioturbation.

  8. Delayed triggering of radio Active Galactic Nuclei in gas-rich minor mergers in the local Universe

    CERN Document Server

    Shabala, Stanislav; Kaviraj, Sugata; Middelberg, Enno; Turner, Ross; Ting, Yuan-Sen; Allison, James; Davis, Tim

    2016-01-01

    We examine the processes triggering star formation and Active Galactic Nucleus (AGN) activity in a sample of 25 low redshift ($z10^7$ K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or LINERs in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of H$\\alpha$ star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same star...

  9. Individuals with chronic low back pain demonstrate delayed onset of the back muscle activity during prone hip extension.

    Science.gov (United States)

    Suehiro, Tadanobu; Mizutani, Masatoshi; Ishida, Hiroshi; Kobara, Kenichi; Osaka, Hiroshi; Watanabe, Susumu

    2015-08-01

    Prone hip extension (PHE) is commonly used in the evaluation of the stability of the lumbopelvic region. There is little evidence of difference in muscle activity onset timing between healthy individuals and individuals with chronic low back pain (CLBP) during PHE. The purpose of this study was to determine if individuals with and without CLBP differ in the onset time of the trunk and hip extensor muscles activity during PHE. The participants were 20 patients with CLBP and 20 healthy individuals. Electromyography data of the erector spinae, multifidus, gluteus maximus, and semitendinosus were collected during PHE using a surface electromyograph. Relative differences in the onset times between each muscle and the prime mover (i.e., the semitendinosus) were calculated. The onsets of the bilateral multifidus and contralateral erector spinae were significantly delayed in the CLBP group compared with the healthy group (pleg movement not being significantly different between the groups. The onset times of the gluteus maximus and ipsilateral erector spinae showed no significant differences between the groups. These results suggest that individuals with CLBP use an altered, and possibly inadequate, trunk muscle recruitment pattern.

  10. Body temperature, activity and melatonin profiles in adults with attention-deficit/hyperactivity disorder and delayed sleep: a case-control study.

    Science.gov (United States)

    Bijlenga, Denise; Van Someren, Eus J W; Gruber, Reut; Bron, Tannetje I; Kruithof, I Femke; Spanbroek, Elise C A; Kooij, J J Sandra

    2013-12-01

    Irregular sleep-wake patterns and delayed sleep times are common in adults with attention-deficit/hyperactivity disorder, but mechanisms underlying these problems are unknown. The present case-control study examined whether circadian abnormalities underlie these sleep problems in a naturalistic home setting. We included 12 medication-naïve patients with attention-deficit/hyperactivity disorder and delayed sleep phase syndrome, and 12 matched healthy controls. We examined associations between sleep/wake rhythm in attention-deficit/hyperactivity disorder and circadian parameters (i.e. salivary melatonin concentrations, core and skin temperatures, and activity patterns) of the patients and controls during five consecutive days and nights. Daily bedtimes were more variable within patients compared with controls (F = 8.19, P sleep onset was on average 1 h longer in patients compared with controls (U = 1117, Z = -2.62, P = 0.009). This interval was even longer in patients with extremely late chronotype. Melatonin, activity and body temperatures were delayed to comparable degrees in patients. Overall temperatures were lower in patients than controls. Sleep-onset difficulties correlated with greater distal-proximal temperature gradient (DPG; i.e. colder hands, r(2)  = -0.32, P = 0.028) in patients. Observed day-to-day bedtime variability of individuals with attention-deficit/hyperactivity disorder and delayed sleep phase syndrome were not reflected in their melatonin profiles. Irregular sleep-wake patterns and delayed sleep in individuals with attention-deficit/hyperactivity disorder and delayed sleep phase syndrome are associated with delays and dysregulations of the core and skin temperatures.

  11. Phase Cascade Bridge Rectifier Array in a 2-D lattice

    CERN Document Server

    Nazari, M; Hong, M K; Mohanty, P; Erramilli, S; Narayan, O

    2016-01-01

    We report on a novel rectification phenomenon in a 2-D lattice network consisting of $N\\times N$ sites with diode and AC source elements with controllable phases. A phase cascade configuration is described in which the current ripple in a load resistor goes to zero in the large $N$ limit, enhancing the rectification efficiency without requiring any external capacitor or inductor based filters. The integrated modular configuration is qualitatively different from conventional rectenna arrays in which the source, rectifier and filter systems are physically disjoint. Exact analytical results derived using idealized diodes are compared to a realistic simulation of commercially available diodes. Our results on nonlinear networks of source-rectifier arrays are potentially of interest to a fast evolving field of distributed power networks.

  12. Harmonic-free line-commutated ac/dc rectifiers

    Energy Technology Data Exchange (ETDEWEB)

    Villablanca, Miguel E. [Electrical Engineering Department, University of Santiago, P.O. Box 10233, Santiago (Chile)

    2009-11-15

    In this paper both a method and apparatus are applied to different configurations of line-commutated ac/dc rectifiers to reduce the distortion of currents flowing from the ac supply. The load may be either inductive or capacitive. The technology involves an accurate shaping of the dc current by using two self-commutated switches. This dc-current shaping is reflected back into the shaping of the ac input currents, which become pure sine waves. Thyristor-based rectifying operation is possible with a simple control circuit, which is able to deal with both rapid load variations and failures in the self-commutated switches. Furthermore, the overlap conduction of bridge thyristors is eliminated completely. Experimental verification is provided from a 400-V 30-kVA 50-Hz laboratory prototype. (author)

  13. Sky-Blue Organic Light Emitting Diode with 37% External Quantum Efficiency Using Thermally Activated Delayed Fluorescence from Spiroacridine-Triazine Hybrid.

    Science.gov (United States)

    Lin, Ting-An; Chatterjee, Tanmay; Tsai, Wei-Lung; Lee, Wei-Kai; Wu, Meng-Jung; Jiao, Min; Pan, Kuan-Chung; Yi, Chih-Lung; Chung, Chin-Lung; Wong, Ken-Tsung; Wu, Chung-Chih

    2016-08-01

    Extremely efficient sky-blue organic electroluminescence with external quantum efficiency of ≈37% is achieved in a conventional planar device structure, using a highly efficient thermally activated delayed fluorescence emitter based on the spiroacridine-triazine hybrid and simultaneously possessing nearly unitary (100%) photoluminescence quantum yield, excellent thermal stability, and strongly horizontally oriented emitting dipoles (with a horizontal dipole ratio of 83%).

  14. Multiphosphine-Oxide Hosts for Ultralow-Voltage-Driven True-Blue Thermally Activated Delayed Fluorescence Diodes with External Quantum Efficiency beyond 20.

    Science.gov (United States)

    Zhang, Jing; Ding, Dongxue; Wei, Ying; Han, Fuquan; Xu, Hui; Huang, Wei

    2016-01-20

    Highly efficient low-voltage-driven -true-blue thermally activated -delayed fluorescence diodes are realized through employing a tri-phosphine oxide host (2,2',4-tris(di(phenyl) -phosphoryl)-diphenylether (DPETPO)) with a record external quantum efficiency of 23.0% and the lowest onset voltage of 2.8 V to date.

  15. The Effects of Constant Time Delay Embedded into Teaching Activities for Teaching the Names of Clothes for Preschool Children with Developmental Disabilities

    Science.gov (United States)

    Odluyurt, Serhat

    2011-01-01

    The general purpose of this study was to examine the effectiveness of constant time delay embedded in activities for teaching clothes name for preschool children with developmental disabilities. This study included four participants having Down syndrome with an age range of 43-46 months. All experimental sessions were conducted in one to one…

  16. Correction: A strongly greenish-blue-emitting Cu4Cl4 cluster with an efficient spin-orbit coupling (SOC): fast phosphorescence versus thermally activated delayed fluorescence.

    Science.gov (United States)

    Chen, Xu-Lin; Yu, Rongmin; Wu, Xiao-Yuan; Liang, Dong; Jia, Ji-Hui; Lu, Can-Zhong

    2016-06-21

    Correction for 'A strongly greenish-blue-emitting Cu4Cl4 cluster with an efficient spin-orbit coupling (SOC): fast phosphorescence versus thermally activated delayed fluorescence' by Xu-Lin Chen et al., Chem. Commun., 2016, 52, 6288-6291.

  17. Highly efficient exciplex organic light-emitting diodes using thermally activated delayed fluorescent emitters as donor and acceptor materials.

    Science.gov (United States)

    Jeon, Sang Kyu; Yook, Kyoung Soo; Lee, Jun Yeob

    2016-06-01

    Highly efficient exciplex type organic light-emitting diodes were developed using thermally activated delayed fluorescent emitters as donors and acceptors of an exciplex. Blue emitting bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (DMAC-DPS) was a donor and 9,9'-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)-1,3-phenylene)bis(9H-carbazole) (DDCzTrz) and 9,9',9″-(5-(4,6-diphenyl-1,3,5-triazin-2-yl)benzene-1,2,3-triyl)tris(9H-carbazole) (TCzTrz) were acceptor materials. The exciplexes of DMAC-DPS:TCzTrz and DMAC-DPS:DDCzTrz resulted in high photoluminescence quantum yield and high quantum efficiency in the green exciplex organic light-emitting diodes. High quantum efficiencies of 13.4% and 15.3% were obtained in the DMAC-DPS:DDCzTrz and DMAC-DPS:TCzTrz exciplex devices.

  18. High-efficiency diphenylsulfon derivatives-based organic light-emitting diode exhibiting thermally activated delayed fluorescence

    CERN Document Server

    Lee, Geon Hyeong

    2016-01-01

    Novel thermally activated delayed fluorescence (TADF) material with diphenyl sulfone (DPS) as an electron acceptor and 3,6-dimethoxycarbazole (DMOC) and 1,3,6,8-Tetramethyl-9H-carbazole (TMC) as electron donors were investigated theoretically for a blue organic light emitting diode (OLED) emitter. We calculate the energies of the first singlet (S1) and first triplet (T1)-excited states of TADF materials by performing density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations on the ground state using a dependence on charge transfer amounts for the optimal Hartree-Fock percentage in the exchange-correlation of TD-DFT. The calculated {\\Delta}EST values of TMC-DPS (0.094 eV) was smaller than DMOC-DPS (0.386 eV) because of the large dihedral angles between the donor and accepter moieties. We show that TMC-DPS would have a suitable blue OLED emitter, because it has a large dihedral angle that creates a small spatial overlap between the HOMO and the LUMO and, consequently, the small {\\Delta}EST an...

  19. Activation of mitochondria-mediated apoptotic pathway in tri-ortho-cresyl phosphate-induced delayed neuropathy.

    Science.gov (United States)

    Zou, Chaoshuang; Kou, Ruirui; Gao, Yuan; Xie, Keqin; Song, Fuyong

    2013-06-01

    Previous studies suggest that abnormal neurons death has been implicated in organophosphate-induced delayed neuropathy (OPIDN). However, the precise mechanism of neuronal death in OPIDN remains largely unknown. In this study, adult hens were treated with a dosage of 750 mg/kg tri-ortho-cresyl phosphate (TOCP) by gavage, and then sacrificed on the time-points of 1, 5, 10, and 21 days after dosing TOCP, respectively. The apoptotic change of spinal cord neurons induced by TOCP was examined, and the role of mitochondria-mediated apoptosis of neurons during OPIDN was investigated. TUNEL assays showed that apoptotic neurons in hen spinal cords began to appear on day 5 following TOCP exposure. Immunohistochemistry and western blot analysis revealed a translocation of cytochrome C from mitochondria to cytoplasm after dosing TOCP. Moreover, the level of Bcl-2, Bcl-xl, Pro-caspase3 and Pro-caspase9 in hen spinal cord was significantly decreased, whereas that of Bax and cleaved-PARP was significantly elevated. Taken together, these findings indicate that the administration of TOCP can induce neuron apoptosis in hen spinal cords, which might be mediated by the activation of mitochondrial apoptotic pathway.

  20. Uncovering Single-Molecule Photophysical Heterogeneity of Bright, Thermally Activated Delayed Fluorescence Emitters Dispersed in Glassy Hosts.

    Science.gov (United States)

    Noriega, Rodrigo; Barnard, Edward S; Ursprung, Benedikt; Cotts, Benjamin L; Penwell, Samuel B; Schuck, P James; Ginsberg, Naomi S

    2016-10-04

    Recently developed all-organic emitters used in display applications achieve high brightness by harvesting triplet populations via thermally activated delayed fluorescence. The photophysical properties of these emitters therefore involve new inherent complexities and are strongly affected by interactions with their host material in the solid state. Ensemble measurements occlude the molecular details of how host-guest interactions determine fundamental properties such as the essential balance of singlet oscillator strength and triplet harvesting. Therefore, using time-resolved fluorescence spectroscopy, we interrogate these emitters at the single-molecule level and compare their properties in two distinct glassy polymer hosts. We find that nonbonding interactions with aromatic moieties in the host appear to mediate the molecular configurations of the emitters, but also promote nonradiative quenching pathways. We also find substantial heterogeneity in the time-resolved photoluminescence of these emitters, which is dominated by static disorder in the polymer. Finally, since singlet-triplet cycling underpins the mechanism for increased brightness, we present the first room-temperature measurement of singlet-triplet equilibration dynamics in this family of emitters. Our observations present a molecular-scale interrogation of host-guest interactions in a disordered film, with implications for highly efficient organic light-emitting devices. Combining a single-molecule experimental technique with an emitter that is sensitive to triplet dynamics, yet read out via fluorescence, should also provide a complementary approach to performing fundamental studies of glassy materials over a large dynamic range of time scales.

  1. A new way towards high-efficiency thermally activated delayed fluorescence devices via external heavy-atom effect

    Science.gov (United States)

    Zhang, Wenzhi; Jin, Jiangjiang; Huang, Zhi; Zhuang, Shaoqing; Wang, Lei

    2016-07-01

    Thermally activated delayed fluorescence (TADF) mechanism is a significant method that enables the harvesting of both triplet and singlet excitons for emission. However, up to now most efforts have been devoted to dealing with the relation between singlet-triplet splitting (ΔEST) and fluorescence efficiency, while the significance of spin-orbit coupling (SOC) is usually ignored. In this contribution, a new method is developed to realize high-efficiency TADF-based devices through simple device-structure optimizations. By inserting an ultrathin external heavy-atom (EHA) perturber layer in a desired manner, it provides useful means of accelerating the T1 → S1 reverse intersystem crossing (RISC) in TADF molecules without affecting the corresponding S1 → T1 process heavily. Furthermore, this strategy also promotes the utilization of host triplets through Förster mechanism during host → guest energy transfer (ET) processes, which helps to get rid of the solely dependence upon Dexter mechanism. Based on this strategy, we have successfully raised the external quantum efficiency (EQE) in 4CzPN-based devices by nearly 38% in comparison to control devices. These findings provide keen insights into the role of EHA played in TADF-based devices, offering valuable guidelines for utilizing certain TADF dyes which possess high radiative transition rate but relatively inefficient RISC.

  2. Positive solutions of a three-point boundary-value problem for differential equations with damping and actively bounded delayed forcing term

    Directory of Open Access Journals (Sweden)

    George L. Karakostas

    2006-08-01

    Full Text Available We provide sufficient conditions for the existence of positive solutions of a three-point boundary value problem concerning a second order delay differential equation with damping and forcing term whose the delayed part is an actively bounded function, a meaning introduced in [19]. By writing the damping term as a difference of two factors one can extract more information on the solutions. (For instance, in an application, given in the last section, we can give the exact value of the norm of the solution.

  3. Calmodulin modulates the delay period between release of calcium from internal stores and activation of calcium influx via endogenous TRP1 channels.

    Science.gov (United States)

    Vaca, Luis; Sampieri, Alicia

    2002-11-01

    In the present study we have explored the role of calmodulin (CaM) and inositol 1,4,5-trisphosphate receptor (IP(3)R) in the communication process activated after the release of calcium from the endoplasmic reticulum (ER) and the activation of calcium influx via endogenous TRP1 channels from Chinese hamster ovary cells. Experiments using combined rapid confocal calcium and electrophysiology measurements uncovered a consistent delay of around 900 ms between the first detectable calcium released from the ER and the activation of the calcium current. This delay was evident with two different methods used to release calcium from the ER: either the blockade of the microsomal calcium ATPase with thapsigargin or activation of bradykinin receptors linked to the IP(3) cascade. Direct application of IP(3) or a peptide from the NH(2)-terminal region of the IP(3)R activated store operated calcium, reducing the delay period. Introduction of CaM into the cell via the patch pipette increased the delay period from 900 +/- 100 ms to 10 +/- 2.1 s (n = 18). Furthermore, the use of selective CaM antagonists W7 and trifluoperazine maleate resulted in a substantial reduction of the delay period to 200 +/- 100 ms with 5 microm trifluoperazine maleate (n = 16) and 150 +/- 50 ms with 500 nm W7 (n = 22). CaM reduced also the current density activated by thapsigargin or brandykinin to about 60% from control. The CaM antagonists did not affect significantly the current density. The results presented here are consistent with an antagonistic effect of IP(3)R and CaM for the activation of store operated calcium after depletion of the ER. The functional competition between the activating effect of IP(3)R and the inhibiting effect of CaM may modulate the delay period between the release of calcium from the ER and the activation of calcium influx observed in different cells, as well as the amount of current activated after depletion of the ER.

  4. Delayed triggering of radio Active Galactic Nuclei in gas-rich minor mergers in the local Universe

    Science.gov (United States)

    Shabala, S. S.; Deller, A.; Kaviraj, S.; Middelberg, E.; Turner, R. J.; Ting, Y. S.; Allison, J. R.; Davis, T. A.

    2016-10-01

    We examine the processes triggering star formation and Active Galactic Nucleus (AGN) activity in a sample of 25 low redshift (z 107 K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or LINERs in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of Hα star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same starburst age. Conventional and VLBI radio imaging shows these AGN to be compact on arcsecond scales. Our modeling suggests that the actual sizes of AGN-inflated radio lobes may be much larger than this, but these are too faint to be detected in existing observations. Deep radio imaging is required to map out the true extent of the AGN, and to determine whether the low star formation rates in radio AGN hosts are a result of the special conditions required for radio jet triggering, or the effect of AGN feedback.

  5. Delayed triggering of radio active galactic nuclei in gas-rich minor mergers in the local Universe

    Science.gov (United States)

    Shabala, S. S.; Deller, A.; Kaviraj, S.; Middelberg, E.; Turner, R. J.; Ting, Y. S.; Allison, J. R.; Davis, T. A.

    2017-02-01

    We examine the processes triggering star formation and active galactic nucleus (AGN) activity in a sample of 25 low-redshift (z 107 K) brightness temperature required for an mJIVE-20 detection allows us to unambiguously identify the radio AGN in our sample. We find three such objects. Our VLBI AGN identifications are classified as Seyferts or low-ionization nuclear emission-line regions (LINERs) in narrow line optical diagnostic plots; mid-infrared colours of our targets and the comparison of Hα star formation rates with integrated radio luminosity are also consistent with the VLBI identifications. We reconstruct star formation histories in our galaxies using optical and UV photometry, and find that these radio AGN are not triggered promptly in the merger process, consistent with previous findings for non-VLBI samples of radio AGN. This delay can significantly limit the efficiency of feedback by radio AGN triggered in galaxy mergers. We find that radio AGN hosts have lower star formation rates than non-AGN radio-selected galaxies at the same starburst age. Conventional and VLBI radio imaging shows these AGN to be compact on arcsecond scales. Our modelling suggests that the actual sizes of AGN-inflated radio lobes may be much larger than this, but these are too faint to be detected in existing observations. Deep radio imaging is required to map out the true extent of the AGN, and to determine whether the low star formation rates in radio AGN hosts are a result of the special conditions required for radio jet triggering, or the effect of AGN feedback.

  6. The Outwardly Rectifying Current of Layer 5 Neocortical Neurons that was Originally Identified as "Non-Specific Cationic" Is Essentially a Potassium Current.

    Directory of Open Access Journals (Sweden)

    Omer Revah

    Full Text Available In whole-cell patch clamp recordings from layer 5 neocortical neurons, blockade of voltage gated sodium and calcium channels leaves a cesium current that is outward rectifying. This current was originally identified as a "non-specific cationic current", and subsequently it was hypothesized that it is mediated by TRP channels. In order to test this hypothesis, we used fluorescence imaging of intracellular sodium and calcium indicators, and found no evidence to suggest that it is associated with influx of either of these ions to the cell body or dendrites. Moreover, the current is still prominent in neurons from TRPC1-/- and TRPC5-/- mice. The effects on the current of various blocking agents, and especially its sensitivity to intracellular tetraethylammonium, suggest that it is not a non-specific cationic current, but rather that it is generated by cesium-permeable delayed rectifier potassium channels.

  7. Delaying discharge after the stimulus significantly decreases muscle activation thresholds with small impact on the selectivity: an in vivo study using TIME.

    Science.gov (United States)

    Maciejasz, Paweł; Badia, Jordi; Boretius, Tim; Andreu, David; Stieglitz, Thomas; Jensen, Winnie; Navarro, Xavier; Guiraud, David

    2015-04-01

    The number of devices for electrical stimulation of nerve fibres implanted worldwide for medical applications is constantly increasing. Stimulation charge is one of the most important parameters of stimulation. High stimulation charge may cause tissue and electrode damage and also compromise the battery life of the electrical stimulators. Therefore, the objective of minimizing stimulation charge is an important issue. Delaying the second phase of biphasic stimulation waveform may decrease the charge required for fibre activation, but its impact on stimulation selectivity is not known. This information is particularly relevant when transverse intrafascicular multichannel electrode (TIME) is used, since it has been designed to provide for high selectivity. In this in vivo study, the rat sciatic nerve was electrically stimulated using monopolar and bipolar configurations with TIME. The results demonstrated that the inclusion of a 100-μs delay between the cathodic and the anodic phase of the stimulus allows to reduce charge requirements by around 30 %, while only slightly affecting stimulation selectivity. This study shows that adding a delay to the typical stimulation waveform significantly ([Formula: see text]) reduces the charge required for nerve fibres activation. Therefore, waveforms with the delayed discharge phase are more suitable for electrical stimulation of nerve fibres.

  8. G-protein-coupled inward rectifier potassium channels involved in corticostriatal presynaptic modulation.

    Science.gov (United States)

    Meneses, David; Mateos, Verónica; Islas, Gustavo; Barral, Jaime

    2015-09-01

    Presynaptic modulation has been associated mainly with calcium channels but recent data suggests that inward rectifier potassium channels (K(IR)) also play a role. In this work we set to characterize the role of presynaptic K(IR) channels in corticostriatal synaptic transmission. We elicited synaptic potentials in striatum by stimulating cortical areas and then determined the synaptic responses of corticostriatal synapsis by using paired pulse ratio (PPR) in the presence and absence of several potassium channel blockers. Unspecific potassium channels blockers Ba(2+) and Cs(+) reduced the PPR, suggesting that these channels are presynaptically located. Further pharmacological characterization showed that application of tertiapin-Q, a specific K(IR)3 channel family blocker, also induced a reduction of PPR, suggesting that K(IR)3 channels are present at corticostriatal terminals. In contrast, exposure to Lq2, a specific K(IR)1.1 inward rectifier potassium channel, did not induce any change in PPR suggesting the absence of these channels in the presynaptic corticostriatal terminals. Our results indicate that K(IR)3 channels are functionally expressed at the corticostriatal synapses, since blockage of these channels result in PPR decrease. Our results also help to explain how synaptic activity may become sensitive to extracellular signals mediated by G-protein coupled receptors. A vast repertoire of receptors may influence neurotransmitter release in an indirect manner through regulation of K(IR)3 channels.

  9. Self-Injection-Locked Magnetron as an Active Ring Resonator Side Coupled to a Waveguide With a Delayed Feedback Loop

    Science.gov (United States)

    Bliokh, Y. P.; Krasik, Y. E.; Felsteiner, J.

    2012-01-01

    The theoretical analysis and numerical simulations of the magnetron operation with a feedback loop were performed assuming that the delay of the electromagnetic wave propagating in the loop is constant whereas the phase of the complex feedback reflection coefficient is varied. Results of simulations showed that by a proper adjustment of values of the time delay and phase of reflection coefficient that determines phase matching between the waves in the resonator and feedback loop, one can increase the magnetron's output power significantly without any other additional measures.

  10. Self-injection-locked magnetron as an active ring resonator side coupled to a waveguide with a delayed feedback loop

    CERN Document Server

    Bliokh, Y P; Felsteiner, J

    2011-01-01

    The theoretical analysis and numerical simulations of the magnetron operation with a feedback loop were performed assuming that the delay of the electromagnetic wave propagating in the loop is constant whereas the phase of the complex feedback reflection coefficient is varied. Results of simulations showed that by a proper adjustment of values of the time delay and phase of reflection coefficient that determines phase matching between the waves in the resonator and feedback loop, one can increase the magnetron's output power significantly without any other additional measures.

  11. Rectifying calibration error of Goldmann applanation tonometer is easy!

    Directory of Open Access Journals (Sweden)

    Nikhil S Choudhari

    2014-01-01

    Full Text Available Purpose: Goldmann applanation tonometer (GAT is the current Gold standard tonometer. However, its calibration error is common and can go unnoticed in clinics. Its company repair has limitations. The purpose of this report is to describe a self-taught technique of rectifying calibration error of GAT. Materials and Methods: Twenty-nine slit-lamp-mounted Haag-Streit Goldmann tonometers (Model AT 900 C/M; Haag-Streit, Switzerland were included in this cross-sectional interventional pilot study. The technique of rectification of calibration error of the tonometer involved cleaning and lubrication of the instrument followed by alignment of weights when lubrication alone didn′t suffice. We followed the South East Asia Glaucoma Interest Group′s definition of calibration error tolerance (acceptable GAT calibration error within ±2, ±3 and ±4 mm Hg at the 0, 20 and 60-mm Hg testing levels, respectively. Results: Twelve out of 29 (41.3% GATs were out of calibration. The range of positive and negative calibration error at the clinically most important 20-mm Hg testing level was 0.5 to 20 mm Hg and -0.5 to -18 mm Hg, respectively. Cleaning and lubrication alone sufficed to rectify calibration error of 11 (91.6% faulty instruments. Only one (8.3% faulty GAT required alignment of the counter-weight. Conclusions: Rectification of calibration error of GAT is possible in-house. Cleaning and lubrication of GAT can be carried out even by eye care professionals and may suffice to rectify calibration error in the majority of faulty instruments. Such an exercise may drastically reduce the downtime of the Gold standard tonometer.

  12. Analysis and design of associative memories based on recurrent neural networks with linear saturation activation functions and time-varying delays.

    Science.gov (United States)

    Zeng, Zhigang; Wang, Jun

    2007-08-01

    In this letter, some sufficient conditions are obtained to guarantee recurrent neural networks with linear saturation activation functions, and time-varying delays have multiequilibria located in the saturation region and the boundaries of the saturation region. These results on pattern characterization are used to analyze and design autoassociative memories, which are directly based on the parameters of the neural networks. Moreover, a formula for the numbers of spurious equilibria is also derived. Four design procedures for recurrent neural networks with linear saturation activation functions and time-varying delays are developed based on stability results. Two of these procedures allow the neural network to be capable of learning and forgetting. Finally, simulation results demonstrate the validity and characteristics of the proposed approach.

  13. Keppen-Lubinsky syndrome is caused by mutations in the inwardly rectifying K+ channel encoded by KCNJ6.

    Science.gov (United States)

    Masotti, Andrea; Uva, Paolo; Davis-Keppen, Laura; Basel-Vanagaite, Lina; Cohen, Lior; Pisaneschi, Elisa; Celluzzi, Antonella; Bencivenga, Paola; Fang, Mingyan; Tian, Mingyu; Xu, Xun; Cappa, Marco; Dallapiccola, Bruno

    2015-02-05

    Keppen-Lubinsky syndrome (KPLBS) is a rare disease mainly characterized by severe developmental delay and intellectual disability, microcephaly, large prominent eyes, a narrow nasal bridge, a tented upper lip, a high palate, an open mouth, tightly adherent skin, an aged appearance, and severe generalized lipodystrophy. We sequenced the exomes of three unrelated individuals affected by KPLBS and found de novo heterozygous mutations in KCNJ6 (GIRK2), which encodes an inwardly rectifying potassium channel and maps to the Down syndrome critical region between DIRK1A and DSCR4. In particular, two individuals shared an in-frame heterozygous deletion of three nucleotides (c.455_457del) leading to the loss of one amino acid (p.Thr152del). The third individual was heterozygous for a missense mutation (c.460G>A) which introduces an amino acid change from glycine to serine (p.Gly154Ser). In agreement with animal models, the present data suggest that these mutations severely impair the correct functioning of this potassium channel. Overall, these results establish KPLBS as a channelopathy and suggest that KCNJ6 (GIRK2) could also be a candidate gene for other lipodystrophies. We hope that these results will prompt investigations in this unexplored class of inwardly rectifying K(+) channels.

  14. CHIP−/−-Mouse Liver: Adiponectin-AMPK-FOXO-Activation Overrides CYP2E1-Elicited JNK1-Activation, Delaying Onset of NASH: Therapeutic Implications

    Science.gov (United States)

    Kim, Sung-Mi; Grenert, James P.; Patterson, Cam; Correia, Maria Almira

    2016-01-01

    Genetic ablation of C-terminus of Hsc70-interacting protein (CHIP) E3 ubiquitin-ligase impairs hepatic cytochrome P450 CYP2E1 degradation. Consequent CYP2E1 gain of function accelerates reactive O2 species (ROS) production, triggering oxidative/proteotoxic stress associated with sustained activation of c-Jun NH2-terminal kinase (JNK)-signaling cascades, pro-inflammatory effectors/cytokines, insulin resistance, progressive hepatocellular ballooning and microvesicular steatosis. Despite this, little evidence of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) was found in CHIP−/−-mice over the first 8–9-months of life. We herein document that this lack of tissue injury is largely due to the concurrent up-regulation and/or activation of the adiponectin-5′-AMP-activated protein kinase (AMPK)-forkhead box O (FOXO)-signaling axis stemming from at the least three synergistic features: Up-regulated expression of adipose tissue adiponectin and its hepatic adipoR1/adipoR2 receptors, stabilization of hepatic AMPKα1-isoform, identified herein for the first time as a CHIP-ubiquitination substrate (unlike its AMPKα2-isoform), as well as nuclear stabilization of FOXOs, well-known CHIP-ubiquitination targets. Such beneficial predominance of the adiponectin-AMPK-FOXO-signaling axis over the sustained JNK-elevation and injurious insulin resistance in CHIP−/−-livers apparently counteracts/delays rapid progression of the hepatic microvesicular steatosis to the characteristic macrovesicular steatosis observed in clinical NASH and/or rodent NASH-models. PMID:27406999

  15. Use of delayed gamma rays for active non-destructive assay of {sup 235}U irradiated by pulsed neutron source (plasma focus)

    Energy Technology Data Exchange (ETDEWEB)

    Andola, Sanjay; Niranjan, Ram [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, T.C., E-mail: tckk@barc.gov.in [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Rout, R.K. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kumar, Ashwani; Paranjape, D.B.; Kumar, Pradeep; Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gupta, S.C. [Applied Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-07-01

    A pulsed neutron source based on plasma focus device has been used for active interrogation and assay of {sup 235}U by monitoring its delayed high energy γ-rays. The method involves irradiation of fissile material by thermal neutrons obtained after moderation of a burst of neutrons emitted upon fusion of deuterium in plasma focus (PF) device. The delayed gamma rays emitted from the fissile material as a consequence of induced fission were detected by a large volume sodium iodide (NaI(Tl)) detector. The detector is coupled to a data acquisition system of 2k input size with 2k ADC conversion gain. Counting was carried out in pulse height analysis mode for time integrated counts up to 100 s while the temporal profile of delayed gamma has been obtained by counting in multichannel scaling mode with dwell time of 50 ms. To avoid the effect of passive (natural) and active (from surrounding materials) backgrounds, counts have been acquired for gamma energy between 3 and 10 MeV. The lower limit of detection of {sup 235}U in the oxide samples with this set-up is estimated to be 14 mg.

  16. Robust Output Feedback Control for Active Seat Suspension Systems with Actuator Time Delay Using µ-Synthesis Approach

    Directory of Open Access Journals (Sweden)

    Mohammad Gudarzi

    2013-10-01

    Full Text Available This study presents a robust output feedback optimal H&infin control synthesis for a class of uncertain seat suspension systems with actuator saturation and an uncertain actuator time delay. A vertical vibration model of human body is added in order to make the modeling of seat suspension systems more accurate. A dynamic controller is considered by using of two measurable states of the model, by real sensors, as output feedback. Moreover, uncertain actuator time delay is considered to guarantee robust performance of the closed-loop system. The controller is derived by using D-K iteration algorithm for constrained systems with norm-bounded uncertainties. The corresponding closed-loop system is asymptotically stable with a guaranteed H&infin performance. Finally, a design example is presented to show the performance and robustness of the developed theoretical results.

  17. 2015 NOAA Ortho-rectified Mosaic of Ortho-rectified Below Mean High Water Color Mosaic of Jacksonville, Florida: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. Exponential Stability of Stochastic Delayed Neural Networks with Inverse Hölder Activation Functions and Markovian Jump Parameters

    Directory of Open Access Journals (Sweden)

    Yingwei Li

    2014-01-01

    properties, the existence and uniqueness of the equilibrium point for SNNs without noise perturbations are proved. Secondly, by applying the Lyapunov-Krasovskii functional approach, stochastic analysis theory, and linear matrix inequality (LMI technique, new delay-dependent sufficient criteria are achieved in terms of LMIs to ensure the SNNs with noise perturbations to be globally exponentially stable in the mean square. Finally, two simulation examples are provided to demonstrate the validity of the theoretical results.

  19. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+ Current: A Simulation Study

    Science.gov (United States)

    Zhang, Yue; Li, Qince; Zhang, Henggui

    2016-01-01

    Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs) could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1). In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker. PMID:26998484

  20. Pacemaker Created in Human Ventricle by Depressing Inward-Rectifier K+ Current: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Yue Zhang

    2016-01-01

    Full Text Available Cardiac conduction disorders are common diseases which cause slow heart rate and syncope. The best way to treat these diseases by now is to implant electronic pacemakers, which, yet, have many disadvantages, such as the limited battery life and infection. Biopacemaker has been expected to replace the electronic devices. Automatic ventricular myocytes (VMs could show pacemaker activity, which was induced by depressing inward-rectifier K+ current (IK1. In this study, a 2D model of human biopacemaker was created from the ventricular endocardial myocytes. We examined the stability of the created biopacemaker and investigated its driving capability by finding the suitable size and spatial distribution of the pacemaker for robust pacing and driving the surrounding quiescent cardiomyocytes. Our results suggest that the rhythm of the pacemaker is similar to that of the single cell at final stable state. The driving force of the biopacemaker is closely related to the pattern of spatial distribution of the pacemaker.

  1. G-protein-coupled inward rectifier potassium current contributes to ventricular repolarization

    DEFF Research Database (Denmark)

    Liang, Bo; Nissen, Jakob D; Laursen, Morten;

    2014-01-01

    The purpose of this study was to investigate the functional role of G-protein-coupled inward rectifier potassium (GIRK) channels in the cardiac ventricle.......The purpose of this study was to investigate the functional role of G-protein-coupled inward rectifier potassium (GIRK) channels in the cardiac ventricle....

  2. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provid...

  3. A Novel Current-Mode Full-Wave Rectifier Based on One CDTA and Two Diodes

    Directory of Open Access Journals (Sweden)

    F. Khateb

    2010-09-01

    Full Text Available Precision rectifiers are important building blocks for analog signal processing. The traditional approach based on diodes and operational amplifiers (OpAmps exhibits undesirable effects caused by limited OpAmp slew rate and diode commutations. In the paper, a full-wave rectifier based on one CDTA and two Schottky diodes is presented. The PSpice simulation results are included.

  4. Three-phase diode rectifiers with low harmonics current injection methods

    CERN Document Server

    Pejovic, Predrag

    2007-01-01

    Presents results of numerous research papers in the area of current injection based rectifiers. This book discusses the principles of current injection, followed by an analysis of various magnetic current injection devices. It concludes with a chapter where the results are generalized to three-phase full-bridge thyristor rectifiers.

  5. Characterization of the chicken inward rectifier K+ channel IRK1/Kir2.1 gene

    Directory of Open Access Journals (Sweden)

    Locke Emily

    2004-11-01

    Full Text Available Abstract Background Inward rectifier potassium channels (IRK contribute to the normal function of skeletal and cardiac muscle cells. The chick inward rectifier K+ channel cIRK1/Kir2.1 is expressed in skeletal muscle, heart, brain, but not in liver; a distribution similar but not identical to that of mouse Kir2.1. We set out to explore regulatory domains of the cIRK1 promoter that enhance or inhibit expression of the gene in different cell types. Results We cloned and characterized the 5'-flanking region of cIRK1. cIRK1 contains two exons with splice sites in the 5'-untranslated region, a structure similar to mouse and human orthologs. cIRK1 has multiple transcription initiation sites, a feature also seen in mouse. However, while the chicken and mouse promoter regions share many regulatory motifs, cIRK1 possesses a GC-richer promoter and a putative TATA box, which appears to positively regulate gene expression. We report here the identification of several candidate cell/tissue specific cIRK1 regulatory domains by comparing promoter activities in expressing (Qm7 and non-expressing (DF1 cells using in vitro transcription assays. Conclusion While multiple transcription initiation sites and the combinatorial function of several domains in activating cIRK1 expression are similar to those seen in mKir2.1, the cIRK1 promoter differs by the presence of a putative TATA box. In addition, several domains that regulate the gene's expression differentially in muscle (Qm7 and fibroblast cells (DF1 were identified. These results provide fundamental data to analyze cIRK1 transcriptional mechanisms. The control elements identified here may provide clues to the tissue-specific expression of this K+ channel.

  6. Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering

    KAUST Repository

    Ouda, Mahmoud H.

    2016-08-29

    A self-biased, cross-coupled, differential rectifier is proposed with enhanced power-conversion efficiency over an extended range of input power. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18μm CMOS technology. The proposed rectifier architecture is compared to the conventional cross-coupled rectifier. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional crosscoupled rectifier. A sensitivity of -15.2dBm (30μW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kω load. © 2004-2012 IEEE.

  7. JAK2 V617F stimulates proliferation of erythropoietin-dependent erythroid progenitors and delays their differentiation by activating Stat1 and other nonerythroid signaling pathways.

    Science.gov (United States)

    Shi, Jiahai; Yuan, Bingbing; Hu, Wenqian; Lodish, Harvey

    2016-11-01

    JAK2 V617F is a mutant-activated JAK2 kinase found in most polycythemia vera (PV) patients; it skews normal proliferation and differentiation of hematopoietic stem and progenitor cells and simulates aberrant expansion of erythroid progenitors. JAK2 V617F is known to activate some signaling pathways not normally activated in mature erythroblasts, but there has been no systematic study of signal transduction pathways or gene expression in erythroid cells expressing JAK2 V617F undergoing erythropoietin (Epo)-dependent terminal differentiation. Here we report that expression of JAK2 V617F in murine fetal liver Epo-dependent progenitors allows them to divide approximately six rather than the normal approximately four times in the presence of Epo, delaying their exit from the cell cycle. Over time, the number of red cells formed from each Epo-dependent progenitor increases fourfold, and these cells eventually differentiate into normal enucleated reticulocytes. We report that purified fetal liver Epo-dependent progenitors express many cytokine receptors additional to the EpoR. Expression of JAK2 V617F triggers activation of Stat5, the only STAT normally activated by Epo, as well as activation of Stat1 and Stat3. Expression of JAK2 V617F also leads to transient induction of many genes not normally activated in terminally differentiating erythroid cells and that are characteristic of other hematopoietic lineages. Inhibition of Stat1 activation blocks JAK2 V617F hyperproliferation of erythroid progenitors, and we conclude that Stat1-mediated activation of nonerythroid signaling pathways delays terminal erythroid differentiation and permits extended cell divisions.

  8. Ordered Mesostructured CdS Nanowire Arrays with Rectifying Properties

    Directory of Open Access Journals (Sweden)

    Yuan Na

    2009-01-01

    Full Text Available Abstract Highly ordered mesoporous CdS nanowire arrays were synthesized by using mesoporous silica as hard template and cadmium xanthate (CdR2 as a single precursor. Upon etching silica, mesoporous CdS nanowire arrays were produced with a yield as high as 93 wt%. The nanowire arrays were characterized by XRD, N2adsorption, TEM, and SEM. The results show that the CdS products replicated from the mesoporous silica SBA-15 hard template possess highly ordered hexagonal mesostructure and fiber-like morphology, analogous to the mother template. The current–voltage characteristics of CdS nanoarrays are strongly nonlinear and asymmetrical, showing rectifying diode-like behavior.

  9. Measurement of Phase Dependent Impedance for 3-phase Diode Rectifier

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Bak, Claus Leth

    2016-01-01

    This paper presents a new method to measure the phase dependent impedance from an experimental set up. Though most of power electronics based system is gradually migrating to IGBT based voltage source converter due to their controllability, the rectifier composed of diode or thyristor components...... are still widely used in AC-DC applications because of their cost effectiveness and reliability. However, these topologies generate harmonic problems in their network due to their switching instant variation caused by the frequency and phase of grid voltage. Hence, a lot of solutions have been proposed...... application. It is found that the phase dependent impedance shows different properties with the impedance profiles, which have been proposed in the research. This paper explains a method to measure the phase dependent impedance profile from an experimental set up. Furthermore, the results are compared...

  10. Impulse control and restrained eating among young women: Evidence for compensatory cortical activation during a chocolate-specific delayed discounting task.

    Science.gov (United States)

    Dong, Debo; Wang, Yulin; Jackson, Todd; Chen, Shuaiyu; Wang, Yu; Zhou, Feng; Chen, Hong

    2016-10-01

    Theory and associated research indicate that people with elevated restrained eating (RE) scores have higher risk for binge eating, future bulimic symptom onset and weight gain. Previous imaging studies have suggested hyper-responsive reward brain area activation in response to food cues contributes to this risk but little is known about associated neural impulse control mechanisms, especially when considering links between depleted cognitive resources related to unsuccessful RE. Towards illuminating this issue, we used a chocolate-specific delayed discounting (DD) task to investigate relations between RE scores, behavior impulsivity, and corresponding neural impulse control correlates in a functional magnetic resonance imaging (fMRI) study of 27 young women. Specifically, participants were required to choose between more immediate, smaller versus delayed, larger hypothetical chocolate rewards following initial consumption of a chocolate. As predicted, RE scores were correlated positively with behavior impulse control levels. More critically, higher RE scores were associated with stronger activation in impulse control region, the dorsal-lateral prefrontal cortex (DLPFC) during the completion of difficult decision trials reflecting higher cognitive demands and resource depletion relative to easy decision trials. Exploratory analyses revealed a positive correlation between RE scores and activity in a reward system hub, the right striatum. Moreover, a positive correlation between left DLPFC and striatum activation was posited to reflect, in part, impulse control region compensation in response to stronger reward signal among women with RE elevations. Findings suggested impulse control lapses may contribute to difficulties in maintaining RE, particularly when cognitive demands are high.

  11. Multistability of memristive Cohen-Grossberg neural networks with non-monotonic piecewise linear activation functions and time-varying delays.

    Science.gov (United States)

    Nie, Xiaobing; Zheng, Wei Xing; Cao, Jinde

    2015-11-01

    The problem of coexistence and dynamical behaviors of multiple equilibrium points is addressed for a class of memristive Cohen-Grossberg neural networks with non-monotonic piecewise linear activation functions and time-varying delays. By virtue of the fixed point theorem, nonsmooth analysis theory and other analytical tools, some sufficient conditions are established to guarantee that such n-dimensional memristive Cohen-Grossberg neural networks can have 5(n) equilibrium points, among which 3(n) equilibrium points are locally exponentially stable. It is shown that greater storage capacity can be achieved by neural networks with the non-monotonic activation functions introduced herein than the ones with Mexican-hat-type activation function. In addition, unlike most existing multistability results of neural networks with monotonic activation functions, those obtained 3(n) locally stable equilibrium points are located both in saturated regions and unsaturated regions. The theoretical findings are verified by an illustrative example with computer simulations.

  12. Attenuation of Rhes activity significantly delays the appearance of behavioral symptoms in a mouse model of Huntington's disease.

    Directory of Open Access Journals (Sweden)

    Brandon A Baiamonte

    Full Text Available Huntington's disease (HD is a neuropsychiatric disorder characterized by choreiform movement of the limbs, cognitive disability, psychosis and dementia. It is invariably associated with an abnormally long CAG expansion within the IT15 gene on human chromosome 4. Although the mutant huntingtin protein is ubiquitously expressed in HD patients, cellular degeneration occurs predominantly in neurons within the corpus striatum and cerebral cortex. The Ras homolog Rhes is expressed very selectively in the precise brain areas affected by HD. Recent in vitro work suggests that Rhes may be a co-factor with mutant huntingtin in cell death. The objective of the present study was to examine whether the inhibition of Rhes would attenuate or delay the symptoms of HD in vivo. We used a transgenic mouse model of HD crossed with Rhes knockout mice to show that the behavioral symptoms of HD are regulated by Rhes. HD(+/Rhes(-/- mice showed significantly delayed expression of HD-like symptoms in this in vivo model. Drugs that block or inhibit the actions of Rhes may be useful as the first treatments for HD.

  13. A Significantly Twisted Spirocyclic Phosphine Oxide as a Universal Host for High-Efficiency Full-Color Thermally Activated Delayed Fluorescence Diodes.

    Science.gov (United States)

    Li, Jing; Ding, Dongxue; Tao, Youtian; Wei, Ying; Chen, Runfeng; Xie, Linghai; Huang, Wei; Xu, Hui

    2016-04-01

    A universal thermally activated delayed fluorescence (TADF) host, 4'-diphenylphosphinoylspiro[fluorene-9,9'-xanthene] (SFXSPO), is constructed with a highly distorted and asymmetric configuration and disordered molecular packing in its solid state. SFXSPO successfully endows its full-color TADF diodes with state-of-the-art performance, e.g., the record external quantum efficiency of 22.5% and 19.1% and internal quantum efficiency of ≈100% for its yellow TADF diodes and single-host full-TADF nearly-white-emitting devices, respectively.

  14. Achieving a balance between small singlet-triplet energy splitting and high fluorescence radiative rate in a quinoxaline-based orange-red thermally activated delayed fluorescence emitter.

    Science.gov (United States)

    Yu, Ling; Wu, Zhongbin; Xie, Guohua; Zhong, Cheng; Zhu, Zece; Cong, Hengjiang; Ma, Dongge; Yang, Chuluo

    2016-09-21

    A new orange-red thermally activated delayed fluorescence (TADF) emitter is designed and synthesized by incorporating a fluorine-substituted quinoxaline as an electron-acceptor and a phenoxazine as an electron-donor. The rational molecular design enables small singlet-triplet energy splitting (ΔEST) and high fluorescence radiative rate (k) for long-wavelength TADF emitters. The organic light emitting diodes (OLEDs) employing the new TADF emitter achieve maximum external quantum efficiencies (EQEs) of 13.9% and 9.0% for the vacuum- and solution-processed OLEDs, respectively.

  15. DNA topoisomerase 2 mutant allele mildly delays the mitotic progression and activates the checkpoint protein kinase Chk1 in fission yeast Schizosaccharomyces pombe.

    Science.gov (United States)

    Yadav, Sudhanshu; Verma, Sumit Kumar; Ahmed, Shakil

    2011-08-01

    DNA topoisomerases are specialized nuclear enzymes that perform topological modifications on double-stranded DNA (dsDNA) and hence are essential for DNA metabolism such as replication, transcription, recombination, condensation and segregation. In a genetic screen, we identified a temperature-sensitive mutant allele of topoisomerase 2 that exhibits conditional synthetic lethality with a chk1 knockout strain. The mutant allele of topoisomerase 2 is defective in chromosome segregation at a non-permissive temperature and there was increase in chromosome segregation defects in the double mutant of top2-10 and chk1 delete at a non-permissive temperature. More importantly, topoisomearse 2 mutant cells mildly delay the mitotic progression at non-permissive temperature that is mediated by checkpoint protein kinase Chk1. Additionally, top2-10 mutant cells also activate the Chk1 at a non-permissive temperature and this activation of Chk1 takes place at the time of mitosis. Interestingly, top2-10 mutant cells retain their viability at a non-permissive temperature if the cells are not allowed to enter into mitosis. Taking together our results, we speculate that in the top2-10 mutant, the segregation of entangled chromatids during mitosis could result in delaying the mitotic progression through the activation of Chk1 kinase.

  16. Investigation on a Novel Discontinuous Pulse-Width Modulation Algorithm for Single-phase Voltage Source Rectifier

    DEFF Research Database (Denmark)

    Qu, Hao; Yang, Xijun; Guo, Yougui

    2014-01-01

    -sequence component injection, in order to reduce power loss and increased overall efficiency. And then by reconstructing the other two phase input voltages and currents, the transformation from stationary frame (abc) to rotating frame (dq frame) is designed. Finally, a PI regulator based controller for single......Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC...

  17. Enhanced Rectification Efficiency In Cascaded Ballistic GaAs/AlGaAs Rectifiers

    Science.gov (United States)

    Wieser, U.; Knop, M.; Koop, P.; Kunze, U.; Reuter, D.; Wieck, A. D.

    2007-04-01

    We report on an enhanced efficiency of inertial-ballistic rectification in a cascade of rectifier stages. Each rectifier stage is composed of a pair of current injecting branches which oppositely merge into a central voltage stem. The voltages obtained at both ends of the stem enable to separate inertial-ballistic and mode-controlled rectification. In a cascade composed of two rectifier stages the total inertial-ballistic signal is enhanced compared to the single contributions while the mode-controlled signal is almost unaffected.

  18. Research on Passivity Based Controller of Three Phase Voltage Source PWM Rectifier

    Directory of Open Access Journals (Sweden)

    Yin Hongren

    2012-09-01

    Full Text Available Euler-Lagrange (EL model of voltage source PWM rectifier is set up based on its model in synchronous dq coordinates. Passivity based controller is designed on the basis of passivity and EL model of voltage source PWM rectifier. Three switching function are educed by passivity based controller. A switching function is only realized in engineering consequently. Voltage source PWM rectifier using passivity based controller has many advantages, such as simpler structure, low total harmonic distortion, and good disturbance rejection performance. Passivity based control law is proved feasible by simulink simulation.  

  19. Activation of nuclear factor-κB in the brain after experimental subarachnoid hemorrhage and its potential role in delayed brain injury.

    Directory of Open Access Journals (Sweden)

    Wan-Chun You

    Full Text Available It has been reported that inflammation is involved in brain injury after subarachnoid hemorrhage (SAH. Nuclear factor-κB (NF-κB is a key transcriptional regulator of inflammatory genes. Here, we used pyrrolidine dithiocarbamate(PDTC, an inhibitor of NF-κB, through intracisternal injection to study the role of NF-κB in delayed brain injury after SAH. A total of 55 rabbits were randomly divided into five groups: the control group; the SAH groups including Day-3, 5, and 7 SAH groups (the rabbits in these groups were sacrificed at 3, 5, 7 days after SAH, respectively; and the PDTC group (n = 11 for each group. Electrophoretic mobility shift assay (EMSA was performed to detect NF-κB DNA-binding activity. The mRNA levels of tumor necrosis factor (TNF-α, interleukin (IL-1β, and intercellular adhesion molecule (ICAM-1 were evaluated by RT-PCR analysis. Deoxyribonucleic acid fragmentation was detected by TUNEL and p65 immunoactivity was assessed by immunohistochemistry. Our results showed the activation of NF-κB after SAH, especially at day 3 and 5. The activated p65 was detected in neurons. NF-κB DNA-binding activity was suppressed by intracisternal administration of PDTC. Increased levels of the TNF-α, IL-1β, and ICAM-1 mRNA were found in the brain at day 5 after SAH, and which were suppressed in the PDTC group. The number of TUNEL-positive cells also decreased significantly in the PDTC group compared with that in the Day-5 SAH group. These results demonstrated that the activated NF-κB in neurons after SAH plays an important role in regulating the expressions of inflammatory genes in the brain, and ultimately contributes to delayed brain injury.

  20. An RF energy harvester system using UHF micropower CMOS rectifier based on a diode connected CMOS transistor.

    Science.gov (United States)

    Shokrani, Mohammad Reza; Khoddam, Mojtaba; Hamidon, Mohd Nizar B; Kamsani, Noor Ain; Rokhani, Fakhrul Zaman; Shafie, Suhaidi Bin

    2014-01-01

    This paper presents a new type diode connected MOS transistor to improve CMOS conventional rectifier's performance in RF energy harvester systems for wireless sensor networks in which the circuits are designed in 0.18  μm TSMC CMOS technology. The proposed diode connected MOS transistor uses a new bulk connection which leads to reduction in the threshold voltage and leakage current; therefore, it contributes to increment of the rectifier's output voltage, output current, and efficiency when it is well important in the conventional CMOS rectifiers. The design technique for the rectifiers is explained and a matching network has been proposed to increase the sensitivity of the proposed rectifier. Five-stage rectifier with a matching network is proposed based on the optimization. The simulation results shows 18.2% improvement in the efficiency of the rectifier circuit and increase in sensitivity of RF energy harvester circuit. All circuits are designed in 0.18 μm TSMC CMOS technology.

  1. Multistability analysis of a general class of recurrent neural networks with non-monotonic activation functions and time-varying delays.

    Science.gov (United States)

    Liu, Peng; Zeng, Zhigang; Wang, Jun

    2016-07-01

    This paper addresses the multistability for a general class of recurrent neural networks with time-varying delays. Without assuming the linearity or monotonicity of the activation functions, several new sufficient conditions are obtained to ensure the existence of (2K+1)(n) equilibrium points and the exponential stability of (K+1)(n) equilibrium points among them for n-neuron neural networks, where K is a positive integer and determined by the type of activation functions and the parameters of neural network jointly. The obtained results generalize and improve the earlier publications. Furthermore, the attraction basins of these exponentially stable equilibrium points are estimated. It is revealed that the attraction basins of these exponentially stable equilibrium points can be larger than their originally partitioned subsets. Finally, three illustrative numerical examples show the effectiveness of theoretical results.

  2. Selected Activities of Citrus Maxima Merr. Fruits on Human Endothelial Cells: Enhancing Cell Migration and Delaying Cellular Aging

    Directory of Open Access Journals (Sweden)

    Paiwan Buachan

    2014-04-01

    Full Text Available Endothelial injury and damage as well as accumulated reactive oxygen species (ROS in aging play a significant role in the development of cardiovascular disease (CVD. Recent studies show an association of high citrus fruit intake with a lower risk of CVD and stroke but the mechanisms involved are not fully understood. This study investigated the effects of pummelo (Citrus maxima Merr. var. Tubtim Siam, CM fruit extract on human umbilical vein endothelial cell (HUVECs migration and aging. The freeze-dried powder of fruit extract was characterized for antioxidant capacity (FRAP assay and certain natural antioxidants, including ascorbic acid, gallic acid, hesperidin, and naringin (HPLC. Short-term (48 h co-cultivation of HUVECs with CM enhanced cell migration as evaluated by a scratch wound assay and Boyden chamber assay. A long-term treatment with CM for 35 days significantly increased HUVEC proliferation capability as indicated by population doubling level (PDL. CM also delayed the onset of aging phenotype shown by senescence-associated β-galactosidase (SA-β-gal staining. Furthermore, CM was able to attenuate increased ROS levels in aged cells when determined by 2′,7′-dichlorodihydrofluorescein diacetate (DCDHF while eNOS mRNA expression was increased but the eNOS protein level was not changed. Thus, further in vivo and clinical studies are warranted to support the use of pummelo as a functional fruit for endothelial health and CVD risk reduction.

  3. Delayed childbearing.

    Science.gov (United States)

    Francis, H H

    1985-06-01

    In many Western nations, including England and Wales, Sweden, and the US, there is a current trend towards delayed childbearing because of women's pursuit of a career, later marriage, a longer interval between marriage and the 1st birth, and the increasing number of divorcees having children in a 2nd marriage. Wives of men in social classes I and II in England and Wales are, on average, having their 1st child at 27.9 years, 1.6 years later than in 1973, and in social classes IV and V, 1.0 years later than in 1973, at a mean age of 23.7 years. Consequently, the total period fertility rate for British women aged 30-34 years, 35-39 years, and 40 and over increased by 4%, 2%, and 4%, respectively, between 1982-83, in contrast to reductions of 2% and 3%, respectively, in the 15-19 year and 20-24 year age groups, with the 25-29-year-olds remaining static. The average maternal mortality for all parties in England and Wales during 1976-78 was 106/million for adolescents, 70.4/million for 20-24 year-olds, and 1162/million for those aged 40 years and older. The specific obstetric and allied conditions which increase with age are the hypertensive diseases of pregnancy, hemorrhage, pulmonary embolism, abortion, cardiac disease, caesarean section, ruptured uterus, and amniotic fluid embolism. The Swedish Medical Birth Registry of all live births and perinatal deaths since 1973 has shown that the risk of late fetal death is significantly greater in women aged 30-39 years than in those of the same parity and gravidity aged 20-24 years. The risk of giving birth to low birth weight babies preterm and at term and of premature labor are similarly increased. The early neonatal death rate also was increased for primigravidas and nulliparas in the 30-39 year age group but not in parous women. This is, in part, due to the rise in incidence of fetal abnormalities with advancing maternal age because of chromosomal and nonchromosomal anomalies. These also appear to be the cause of the

  4. Graphene ballistic nano-rectifier with very high responsivity

    Science.gov (United States)

    Auton, Gregory; Zhang, Jiawei; Kumar, Roshan Krishna; Wang, Hanbin; Zhang, Xijian; Wang, Qingpu; Hill, Ernie; Song, Aimin

    2016-05-01

    Although graphene has the longest mean free path of carriers of any known electronic material, very few novel devices have been reported to harness this extraordinary property. Here we demonstrate a ballistic nano-rectifier fabricated by creating an asymmetric cross-junction in single-layer graphene sandwiched between boron nitride flakes. A mobility ~200,000 cm2 V-1 s-1 is achieved at room temperature, well beyond that required for ballistic transport. This enables a voltage responsivity as high as 23,000 mV mW-1 with a low-frequency input signal. Taking advantage of the output channels being orthogonal to the input terminals, the noise is found to be not strongly influenced by the input. Hence, the corresponding noise-equivalent power is as low as 0.64 pW Hz-1/2. Such performance is even comparable to superconducting bolometers, which however need to operate at cryogenic temperatures. Furthermore, output oscillations are observed at low temperatures, the period of which agrees with the lateral size quantization.

  5. Finite element modeling of electrically rectified piezoelectric energy harvesters

    Science.gov (United States)

    Wu, P. H.; Shu, Y. C.

    2015-09-01

    Finite element models are developed for designing electrically rectified piezoelectric energy harvesters. They account for the consideration of common interface circuits such as the standard and parallel-/series-SSHI (synchronized switch harvesting on inductor) circuits, as well as complicated structural configurations such as arrays of piezoelectric oscillators. The idea is to replace the energy harvesting circuit by the proposed equivalent load impedance together with the capacitance of negative value. As a result, the proposed framework is capable of being implemented into conventional finite element solvers for direct system-level design without resorting to circuit simulators. The validation based on COMSOL simulations carried out for various interface circuits by the comparison with the standard modal analysis model. The framework is then applied to the investigation on how harvested power is reduced due to fabrication deviations in geometric and material properties of oscillators in an array system. Remarkably, it is found that for a standard array system with strong electromechanical coupling, the drop in peak power turns out to be insignificant if the optimal load is carefully chosen. The second application is to design broadband energy harvesting by developing array systems with suitable interface circuits. The result shows that significant broadband is observed for the parallel (series) connection of oscillators endowed with the parallel-SSHI (series-SSHI) circuit technique.

  6. Wind Solar Hybrid System Rectifier Stage Topology Simulation

    Directory of Open Access Journals (Sweden)

    Anup M. Gakare

    2014-06-01

    Full Text Available This paper presents power-control strategies of a grid-connected hybrid generation system with versatile power transfer. The hybrid system allows maximum utilization of freely available renewable sources like wind and photovoltaic energies. This paper presents a new system configuration of the multi input rectifier stage for a hybrid wind and photovoltaic energy system. This configuration allows the two sources to supply the load simultaneously depending on the availability of the energy sources maximum power from the sun when it is available. An adaptive MPPT algorithm with a standard perturbs and observed method will be used for the Photo Voltaic system. The main advantage of the hybrid system is to give continuous power supply to the load. The gating pulses to the inverter switches are implemented with conventional and fuzzy controller. This hybrid wind-photo voltaic system is modeled in MATLAB/ SIMULINK environment. Simulation circuit is analyzed and results are presented for this hybrid wind and solar energy system.

  7. Generalized space vector control for current source inverters and rectifiers

    Directory of Open Access Journals (Sweden)

    Roseline J. Anitha

    2016-06-01

    Full Text Available Current source inverters (CSI is one of the widely used converter topology in medium voltage drive applications due to its simplicity, motor friendly waveforms and reliable short circuit protection. The current source inverters are usually fed by controlled current source rectifiers (CSR with a large inductor to provide a constant supply current. A generalized control applicable for both CSI and CSR and their extension namely current source multilevel inverters (CSMLI are dealt in this paper. As space vector pulse width modulation (SVPWM features the advantages of flexible control, faster dynamic response, better DC utilization and easy digital implementation it is considered for this work. This paper generalizes SVPWM that could be applied for CSI, CSR and CSMLI. The intense computation involved in framing a generalized space vector control are discussed in detail. The algorithm includes determination of band, region, subregions and vectors. The algorithm is validated by simulation using MATLAB /SIMULINK for CSR 5, 7, 13 level CSMLI and for CSR fed CSI.

  8. 2012 NOAA Color Ortho-rectified Mosaic of Corpus Christi to Saint Charles Bay, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2011 NOAA Ortho-rectified Mosaic of Texas: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2016 NOAA NGS Ortho-rectified Color Mosaic of Corpus Christi and Port Ingleside, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2013 NOAA Ortho-rectified Color Mosaic of the port of Panama City, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of MISSISSIPPI RIVER - LAPLACE TO VENICE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of MISSISSIPPI RIVER...

  13. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Grays Harbor and Westport, Washington

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Skagway, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2009 NOAA Ortho-rectified Infrared Mosaic of Georgia: Port of Savannah

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2009 NOAA Ortho-rectified Near Infrared Mosaic of Georgia: Kings Bay and Fernandina Beach

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2013 NOAA Ortho-rectified Color Mean High Water Mosaic of North San Francisco Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2011 NOAA Color MHW Ortho-rectified Mosaic of Amelia Island and Nassau River, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2011 NOAA Ortho-rectified Mosaic of Intracoastal City, Louisiana (NODC Accession 0075831)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2013 NOAA Ortho-rectified Color Mosaic of California: Port of San Diego

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Ketchikan Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2011 NOAA Color Ortho-rectified Mosaic of Eastern Lake Michigan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2012 NOAA Color MLLW Ortho-rectified Mosaic of Fort Moultrie to Northeast Point, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2010 NOAA Ortho-rectified Color Mosaic of Port Arthur - Beaumont, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2015 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Ashtabula, Ohio

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2013 NOAA Ortho-rectified Color Mosaic of Intercoastal Waterway - Calcasieu Lake to Vermillion Bay, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Baton Rouge, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of South Slough NERR, Oregon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2016 NOAA NGS Ortho-rectified Color Mosaic of Homer and Seldovia, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2014 NOAA Ortho-rectified Near-Infrared Mosaic of port of Key West, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2011 NOAA Ortho-rectified Mosaic of Tallaboa, Puerto Rico (NODC Accession 0074381)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Alabama: Eastern Mississippi Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2012 NOAA Color MLLW Ortho-rectified Mosaic of Sewee Bay to Santee River, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2013 NOAA Ortho-rectified Color Mosaic of Florida: Lake Okeechobee

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2011 NOAA Ortho-rectified Mosaic of Isle of Shoals New Hampshire (MLLW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2015 NOAA Ortho-rectified Near-Infrared Mosaic of the port of Two Harbors, Minnesota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2010 NOAA Ortho-rectified Mosaic of Louisiana: Mississippi River - Baton Rouge to Southwest Pass

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2012 NOAA Ortho-rectified Color Mosaic of Redwood City, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of BEAUMONT, ORANGE, PORT AUTHUR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of BEAUMONT, ORANGE,...

  20. 2016 NOAA NGS Ortho-rectified Color Mosaic of Ketchikan Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2012 NOAA Ortho-rectified Color Mosaic of Bremerton and Manchester, Washington

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Dillingham, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2016 NOAA NGS Ortho-rectified Color Mosaic of Valdez, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2011 NOAA Ortho-rectified Mosaic of New Jersey: Cape May to Absecon Inlet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of PORT OF GEORGETOWN - CSCAP

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of PORT OF GEORGETOWN...

  6. 2009 NOAA Ortho-rectified RGB Mosaic of Savannah, Georgia (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2012 NOAA Color Ortho-rectified Mosaic of Trinity Bay, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2009 NOAA Ortho-rectified Infrared Mosaic of Georgia: Port of Savannah (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2016 NOAA NGS Ortho-rectified Color Mosaic of Big Carlos Pass, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Bodega Bay to Shelter Cove, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Pescadero Point to Bodega Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2011 NOAA Ortho-rectified Mosaic of Brownsville Ship Channel, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2015 NOAA Ortho-rectified Color Mosaic of the port of Two Harbors, Minnesota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2012 NOAA Ortho-rectified Color Mosaic of Oregon: Lake Umatilla to Clarkson

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2012 NOAA Ortho-rectified Near-Infrared Mosaic of Oregon: Lake Umatilla to Clarkson

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2011 NOAA Ortho-rectified Near-Infrared Mosaic of Isle of Shoals, New Hampshire (MLLW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2015 NOAA NGS Ortho-rectified Mean High Water Color Mosaic of Augusta to Newcastle, Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Lopez Rock to Pescadero Point, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2015 NOAA NGS Ortho-rectified Color Mosaic of Jacksonville Beach to Mosquito Lagoon, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2012 NOAA Ortho-rectified Color Mosaic of Sacramento Deep Water Ship Channel, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Alabama: Eastern Mississippi Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2016 NOAA NGS Ortho-rectified Color Mosaic of St. Paul Island, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Seal Rock to Lopez Rock, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Juneau and Auke Bay, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2011 NOAA Ortho-rectified Color Mosaic of Sewee Bay to Santee River, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2011 NOAA Ortho-rectified Mosaic of Colorado River, Texas (NODC Accession 0105604)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2010 NOAA Ortho-rectified Near-infrared Mosaic of Port Arthur - Beaumont, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2013 NOAA Ortho-rectified Mean High Water Color Mosaic of Louisiana: Timbalier Islandt

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2011 NOAA Ortho-rectified Mosaic of Matagorda Ship Channel, Texas (NODC Accession 0105604(

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2011 NOAA Ortho-rectified Mosaic of Yabucoa, Puerto Rico (NODC Accession 0074381)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2016 NOAA NGS Ortho-rectified Color Mosaic of Cordova, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2012 NOAA Ortho-rectified Color MHW Mosaic of Washington: Seattle and Lake Washington Ship Canal

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2016 NOAA NGS Ortho-rectified Color Mosaic of Skagway, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2016 NOAA NGS Ortho-rectified Color Mosaic of Snug Harbor, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Kenai and Nikiski, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2016 NOAA NGS Ortho-rectified Color Mosaic of Baton Rouge, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of St. Paul Island, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2011 NOAA Ortho-rectified Mosaic of Galveston, Texas (NODC Accession 0105604)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2014 NOAA Ortho-rectified Mosaic of Hurricane Sandy Coastal Impact Area

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles at 0.35m GSD created for NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative in Hurricane Sandy coastal...

  20. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of CHOCTAWHATCHEE BAY

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of CHOCTAWHATCHEE BAY....

  1. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of LAKE CHARLES

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of LAKE CHARLES. The...

  2. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of LAKE CHARLES (NODC Accession 0075827)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of LAKE CHARLES. The...

  3. 2012 NOAA Near Infrared MLLW Ortho-rectified Mosaic of Amelia Island and Nassau River, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2013 NOAA Ortho-rectified Color Mosaic of Virginia: Norfolk, Hampton Roads,and Newport News

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2012 NOAA NIR Ortho-rectified Mosaic of Oregon: Ports of Longview, Kalama, Vancouver, and Portland

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2011 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of CHOCTAWHATCHEE BAY

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of CHOCTAWHATCHEE BAY....

  7. 2012 NOAA Ortho-rectified Color MLLW Mosaic of coastal Curry County, Oregon

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2012 Color NOAA Ortho-rectified Mosaic of Seadrift to Palacios, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2015 NOAA Ortho-rectified Color Mosaic of Delaware River: Marcus Hook to Philadelphia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2012 NOAA Ortho-rectified Color Mosaic of Oregon: Columbia River - Bonneville Dam to Lake Umatilla

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Whittier, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2012 NOAA Ortho-rectified Color Mosaic Stockton Deep Water Channel,California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2011 NOAA Ortho-rectified Color Mosaic of Great Bay, New Hampshire

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2010 NOAA Ortho-rectified Mosaic from Color Aerial Imagery of MISSISSIPPI RIVER - LAPLACE TO VENICE

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative of MISSISSIPPI RIVER -...

  15. 2011 NOAA Ortho-rectified Color Mosaic of Northeast Point to Murphy Island, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2012 NOAA Ortho-rectified Color Mosaic of Port of Everett, Washington

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Long Bay, North Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2013 NOAA Ortho-rectified Color Mean High Water Mosaic of South San Francisco Bay California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2016 NOAA NGS Ortho-rectified Color Mosaic of Seward, Alaska

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2014 NOAA Ortho-rectified Color Mosaic of the port of Miami, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. Two cystic fibrosis transmembrane conductance regulator mutations have different effects on both pulmonary phenotype and regulation of outwardly rectified chloride currents.

    OpenAIRE

    Fulmer, S B; Schwiebert, E M; M.M. Morales; Guggino, W B; Cutting, G R

    1995-01-01

    Cystic fibrosis (CF), a disorder of electrolyte transport manifest in the lungs, pancreas, sweat duct, and vas deferens, is caused by mutations in the CF transmembrane conductance regulator (CFTR). The CFTR protein has been shown to function as a cAMP-activated chloride channel and also regulates a separate protein, the outwardly rectifying chloride channel (ORCC). To determine the consequence of disease-producing mutations upon these functions, mutant CFTR was transiently expressed in Xenopu...

  2. New Analysis and Design of a RF Rectifier for RFID and Implantable Devices

    Directory of Open Access Journals (Sweden)

    Xiong-Fei Tao

    2011-06-01

    Full Text Available New design and optimization of charge pump rectifiers using diode-connected MOS transistors is presented in this paper. An analysis of the output voltage and Power Conversion Efficiency (PCE is given to guide and evaluate the new design. A novel diode-connected MOS transistor for UHF rectifiers is presented and optimized, and a high efficiency N-stage charge pump rectifier based on this new diode-connected MOS transistor is designed and fabricated in a SMIC 0.18-μm 2P3M CMOS embedded EEPROM process. The new diode achieves 315 mV turn-on voltage and 415 nA reverse saturation leakage current. Compared with the traditional rectifier, the one based on the proposed diode-connected MOS has higher PCE, higher output voltage and smaller ripple coefficient. When the RF input is a 900-MHz sinusoid signal with the power ranging from −15 dBm to −4 dBm, PCEs of the charge pump rectifier with only 3-stage are more than 30%, and the maximum output voltage is 5.5 V, and its ripple coefficients are less than 1%. Therefore, the rectifier is especially suitableto passive UHF RFID tag IC and implantable devices.

  3. Rectifying Properties of a Nitrogen/Boron-Doped Capped-Carbon-Nanotube-Based Molecular Junction

    Institute of Scientific and Technical Information of China (English)

    ZHAO Peng; LIU De-Sheng; ZHANG Ying; WANG Pei-Ji; ZHANG Zhong

    2011-01-01

    @@ Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbonnanotube-based molecular junction.Obvious rectifying behavior is observed and it is strongly dependent on the doping site.The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer.Moreover, the rectifying performance can be further improved by adjusting the distance between the Cso nanotube caps.%Based on the non-equilibrium Green's function method and first-principles density functional theory calculations, we investigate the electronic transport properties of a nitrogen/boron-doped capped-single-walled carbon-nanotube-based molecular junction. Obvious rectifying behavior is observed and it is strongly dependent on the doping site. The best rectifying performance can be carried out when the nitrogen/boron atom dopes at a carbon site in the second layer. Moreover, the rectifying performance can be further improved by adjusting the distance between the C60 nanotube caps.

  4. Development of a photonuclear activation file and measurement of delayed neutron spectra; Creation d'une bibliotheque d'activation photonucleaire et mesures de spectres d'emission de neutrons retardes

    Energy Technology Data Exchange (ETDEWEB)

    Giacri-Mauborgne, M.L

    2005-11-15

    This thesis work consists in two parts. The first part is the description of the creation of a photonuclear activation file which will be used to calculated photonuclear activation. To build this file we have used different data sources: evaluations but also calculations done using several cross sections codes (HMS-ALICE, GNASH, ABLA). This file contains photonuclear activation cross sections for more than 600 nuclides and fission fragments distributions for 30 actinides at tree different Bremsstrahlung energies and the delay neutron spectrum associated. These spectra are not in good agreement with experimental data. That is why we decided to launch measurement of delayed neutrons spectra from photofission. The second part of this thesis consists in demonstrating the possibility to do such measurements at the ELSA accelerator facility. To that purpose, we have developed the detection, the acquisition system and the analysis method of such spectra. These were tested for the measurement of the delayed neutron spectrum of uranium-238 after irradiation in a 2 MeV neutron flux. Finally, we have measured the delayed neutron spectrum of uranium-238 after irradiation in a 15 MeV Bremsstrahlung flux. We compare our results with experimental data. The experiment has allowed us to improve the value of {nu}{sub p}-bar with an absolute uncertainty below 7%, we propose {nu}{sub p}-bar = (3.03 {+-} 0.02) n/100 fissions, and to correct the Nikotin's parameters for the six group representation. Particularly, we have improved the data concerning the sixth group by taking into account results from different irradiation times.

  5. Sirtuin 1 (SIRT1 activation mediates sildenafil induced delayed cardioprotection against ischemia-reperfusion injury in mice.

    Directory of Open Access Journals (Sweden)

    Mona Shalwala

    Full Text Available BACKGROUND: It has been well documented that phosphodiesterase-5 inhibitor, sildenafil (SIL protects against myocardial ischemia/reperfusion (I-R injury. SIRT1 is part of the class III Sirtuin family of histone deacetylases that deacetylates proteins involved in cellular stress response including those related to I-R injury. OBJECTIVE/HYPOTHESIS: We tested the hypothesis that SIL-induced cardioprotection may be mediated through activation of SIRT1. METHODS: Adult male ICR mice were treated with SIL (0.7 mg/kg, i.p., Resveratrol (RSV, 5 mg/kg, a putative activator of SIRT1 used as the positive control, or saline (0.2 mL. The hearts were harvested 24 hours later and homogenized for SIRT1 activity analysis. RESULTS: Both SIL- and RSV-treated mice had increased cardiac SIRT1 activity (P<0.001 as compared to the saline-treated controls 24 hours after drug treatment. In isolated ventricular cardiomyocytes, pretreatment with SIL (1 µM or RSV (1 µM for one hour in vitro also upregulated SIRT1 activity (P<0.05. We further examined the causative relationship between SIRT1 activation and SIL-induced late cardioprotection. Pretreatment with SIL (or RSV 24 hours prior to 30 min ischemia and 24 hours of reperfusion significantly reduced infarct size, which was associated with a significant increase in SIRT1 activity (P<0.05. Moreover, sirtinol (a SIRT1 inhibitor, 5 mg/kg, i.p. given 30 min before I-R blunted the infarct-limiting effect of SIL and RSV (P<0.001. CONCLUSION: Our study shows that activation of SIRT1 following SIL treatment plays an essential role in mediating the SIL-induced cardioprotection against I-R injury. This newly identified SIRT1-activating property of SIL may have enormous therapeutic implications.

  6. Highly Efficient Sky-Blue Fluorescent Organic Light Emitting Diode Based on Mixed Cohost System for Thermally Activated Delayed Fluorescence Emitter (2CzPN).

    Science.gov (United States)

    Sun, Jin Won; Kim, Kwon-Hyeon; Moon, Chang-Ki; Lee, Jeong-Hwan; Kim, Jang-Joo

    2016-04-20

    The mixed cohosts of 1,3-bis(N-carbazolyl)benzene and 2,8-bis(diphenylphosphoryl)dibenzothiophene have been developed for a highly efficient blue fluorescent oragnic light emitting diode (OLED) doped with a thermally activated delayed fluorescence (TADF) emitter [4,5-di (9H-carbazol-9-yl) phthalonitrile (2CzPN)]. We have demonstrated one of the highest external quantum efficiency of 21.8% in blue fluorescent OLEDs, which is identical to the theoretically achievable maximum electroluminescence efficiency using the emitter. Interestingly, the efficiency roll-off is large even under the excellent charge balance in the device and almost the same as the single host based devices, indicating that the efficiency roll-off in 2CzPN based TADF host is related to the material characteristics, such as low reverse intesystem crossing rate rather than charge imbalance.

  7. Review of organic light-emitting diodes with thermally activated delayed fluorescence emitters for energy-efficient sustainable light sources and displays

    Science.gov (United States)

    Volz, Daniel

    2016-04-01

    Thermally activated delayed fluorescence (TADF) is an emerging hot topic. Even though this photophysical mechanism itself has been described more than 50 years ago and optoelectronic devices with organic matter have been studied, improved, and even commercialized for decades now, the realization of the potential of TADF organic light-emitting diodes (OLEDs) happened only recently. TADF has been proven to be an attractive and very efficient alternative for phosphorescent materials, such as dopants in OLEDs, light-emitting electrochemical cells as well as potent emitters for chemiluminescence. In this review, the TADF concept is introduced in terms that are also understandable for nonchemists. The basic concepts behind this mechanism as well as state-of-the-art examples are discussed. In addition, the future economic impact, especially for the lighting and display market, is addressed here. We conclude that TADF materials are especially helpful to realize efficient, durable deep blue and white displays.

  8. Biophysical characterization of inwardly rectifying potassium currents (I(K1) I(K,ACh), I(K,Ca)) using sinus rhythm or atrial fibrillation action potential waveforms

    DEFF Research Database (Denmark)

    Tang, Chuyi; Skibsbye, Lasse; Yuan, Lei

    2015-01-01

    to voltage protocols adapted from atrial action potentials recorded in human tissue at 1 and 3 Hz. The current recordings were performed in the HEK-293 heterologous cell system expressing either I(K1), I(K,ACh) or I(K,Ca) to establish the individual contribution of each of these currents during the voltage...... changes of atrial action potential waveforms. I(K1) primarily contributes to the atrial electrophysiology at the latter part of repolarization and during the diastolic phase, while both I(K,Ca) under high [Ca2+]i and I(K,ACh) contribute relatively most during repolarization.......Although several physiological, pathophysiological and regulatory properties of classical inward rectifier K+ current I(K1), G-protein coupled inwardly-rectifying K+ current I(K,ACh) and the small-conductance Ca2+ activated K+ current I(K,Ca) have been identified, quantitative biophysical details...

  9. Ketogenic diet delays the phase of circadian rhythms and does not affect AMP-activated protein kinase (AMPK) in mouse liver.

    Science.gov (United States)

    Genzer, Yoni; Dadon, Maayan; Burg, Chen; Chapnik, Nava; Froy, Oren

    2015-12-05

    Ketogenic diet (KD) is used for weight loss or to treat epilepsy. KD leads to liver AMP-activated protein kinase (AMPK) activation, which would be expected to inhibit gluconeogenesis. However, KD leads to increased hepatic glucose output. As AMPK and its active phosphorylated form (pAMPK) show circadian oscillation, this discrepancy could stem from wrong-time-of-day sampling. The effect of KD was tested on mouse clock gene expression, AMPK, mTOR, SIRT1 and locomotor activity for 2 months and compared to low-fat diet (LFD). KD led to 1.5-fold increased levels of blood glucose and insulin. Brain pAMPK/AMPK ratio was 40% higher under KD, whereas that in liver was not affected. KD led to 40% and 20% down-regulation of the ratio of pP70S6K/P70S6K, the downstream target of mTOR, in the brain and liver, respectively. SIRT1 levels were 40% higher in the brain, but 40% lower in the liver of KD-fed mice. Clock genes showed delayed rhythms under KD. In the brain of KD-fed mice, amplitudes of clock genes were down-regulated, whereas 6-fold up-regulation was found in the liver. The metabolic state under KD indicates reduced satiety in the brain and reduced anabolism alongside increased gluconeogenesis in the liver.

  10. Internalization of EGF receptor following lipid rafts disruption in keratinocytes is delayed and dependent on p38 MAPK activation

    DEFF Research Database (Denmark)

    Lambert, S.; Ameels, H.; Gniadecki, R.;

    2008-01-01

    internalization without participation of the ligand under the control of p38 MAPK during stress conditions. Since cholesterol depletion using methyl-beta-cyclodextrin is known to induce ligand-independent activation of EGFR in keratinocytes, we investigated by confocal microscopy and ligand-binding tests...

  11. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  12. On Xunzi's Standpoints on Linguistics——From Xunzi's Doctrine of"Rectifying Names"%On Xunzi' s Standpoints on Linguistics--From Xunzi's Doctrine of"Rectifying Names"

    Institute of Scientific and Technical Information of China (English)

    佟倩

    2010-01-01

    Xunzi's"Rectifying Names"involved different aspects of language:the nature of language,the functions of language,the standards to rectify names,and also some other aspects of general linguistics.We should not hesitate to say Xunzi was the founder of our Chinese linguistics.This paper now discusses Xunzi's different linguistic standpoints by going over his"Rectifying Names."

  13. Macrophage peroxisome proliferator-activated receptor γ deficiency delays skin wound healing through impairing apoptotic cell clearance in mice

    OpenAIRE

    Chen, H.; Shi, R.; Luo, B.; Yang, X.; Qiu, L; Xiong, J.; Jiang, M; Y. Liu; Zhang, Z; Wu, Y

    2015-01-01

    Skin wound macrophages are key regulators of skin repair and their dysfunction causes chronic, non-healing skin wounds. Peroxisome proliferator-activated receptor gamma (PPARγ) regulates pleiotropic functions of macrophages, but its contribution in skin wound healing is poorly defined. We observed that macrophage PPARγ expression was upregulated during skin wound healing. Furthermore, macrophage PPARγ deficiency (PPARγ-knock out (KO)) mice exhibited impaired skin wound healing with reduced co...

  14. Manipulating the Electronic Excited State Energies of Pyrimidine-Based Thermally Activated Delayed Fluorescence Emitters To Realize Efficient Deep-Blue Emission.

    Science.gov (United States)

    Komatsu, Ryutaro; Ohsawa, Tatsuya; Sasabe, Hisahiro; Nakao, Kohei; Hayasaka, Yuya; Kido, Junji

    2017-02-08

    The development of efficient and robust deep-blue emitters is one of the key issues in organic light-emitting devices (OLEDs) for environmentally friendly, large-area displays or general lighting. As a promising technology that realizes 100% conversion from electrons to photons, thermally activated delayed fluorescence (TADF) emitters have attracted considerable attention. However, only a handful of examples of deep-blue TADF emitters have been reported to date, and the emitters generally show large efficiency roll-off at practical luminance over several hundreds to thousands of cd m(-2), most likely because of the long delayed fluorescent lifetime (τd). To overcome this problem, we molecularly manipulated the electronic excited state energies of pyrimidine-based TADF emitters to realize deep-blue emission and reduced τd. We then systematically investigated the relationships among the chemical structure, properties, and device performances. The resultant novel pyrimidine emitters, called Ac-XMHPMs (X = 1, 2, and 3), contain different numbers of bulky methyl substituents at acceptor moieties, increasing the excited singlet (ES) and triplet state (ET) energies. Among them, Ac-3MHPM, with a high ET of 2.95 eV, exhibited a high external quantum efficiency (ηext,max) of 18% and an ηext of 10% at 100 cd m(-2) with Commission Internationale de l'Eclairage chromaticity coordinates of (0.16, 0.15). These efficiencies are among the highest values to date for deep-blue TADF OLEDs. Our molecular design strategy provides fundamental guidance to design novel deep-blue TADF emitters.

  15. Nicotine at clinically relevant concentrations affects atrial inward rectifier potassium current sensitive to acetylcholine.

    Science.gov (United States)

    Bébarová, Markéta; Matejovič, Peter; Švecová, Olga; Kula, Roman; Šimurdová, Milena; Šimurda, Jiří

    2017-02-03

    Nicotine abuse is associated with variety of diseases including arrhythmias, most often atrial fibrillation (AF). Altered inward rectifier potassium currents including acetylcholine-sensitive current I K(Ach) are known to be related to AF pathogenesis. Since relevant data are missing, we aimed to investigate I K(Ach) changes at clinically relevant concentrations of nicotine. Experiments were performed by the whole cell patch clamp technique at 23 ± 1 °C on isolated rat atrial myocytes. Nicotine was applied at following concentrations: 4, 40 and 400 nM; ethanol at 20 mM (∼0.09%). Nicotine at 40 and 400 nM significantly activated constitutively active component of I K(Ach) with the maximum effect at 40 nM (an increase by ∼100%); similar effect was observed at -110 and -50 mV. Changes at 4 nM nicotine were negligible on average. Coapplication of 40 nM nicotine and 20 mM ethanol (which is also known to activate this current) did not show cumulative effect. In the case of acetylcholine-induced component of I K(Ach), a dual effect of nicotine and its correlation with the current magnitude in control were apparent: the current was increased by nicotine in the cells showing small current in control and vice versa. The effect of 40 and 400 nM nicotine on acetylcholine-induced component of I K(Ach) was significantly different at -110 and -50 mV. We conclude that nicotine at clinically relevant concentrations significantly increased constitutively active component of I K(Ach) and showed a dual effect on its acetylcholine-induced component, similarly as ethanol. Synchronous application of nicotine and ethanol did not cause additive effect.

  16. RECTIFYING EFFECT OF POLYANILINE(PANI)/N-TYPE POROUS SILICONE HETEROJUNCTION

    Institute of Scientific and Technical Information of China (English)

    Mei-xiang Wan; Yong-ming Li

    1999-01-01

    Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell,were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of the preparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. The rectifying parameters of Al/PS-PANI/Au cell were determined to be γ= 1.8×101~1.0×105 for the rectifying ratio at 3 V, n = 3~12 for the ideal factor, j0 = 8.0×10-5~5.6×10-2 mA/cm2 for the reversed saturated current density, and φb = 0.67~0.83 V for the barrier height, respectively. The best rectifying heterojunction diode made between PANI and n-type PS with higher rectifying factor (γ=1.0×105 at 3V ), output current (> 1500mA/cm2 at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS before evaporating Al electrode.

  17. MODIFICATIONS OF DIODE RECTIFIER CIRCUITS FOR CONTINUOUS INSULATION MEASUREMENT IN LIVE AC IT NETWORKS

    Directory of Open Access Journals (Sweden)

    Piotr Olszowiec

    2016-05-01

    Full Text Available Purpose. In the paper there are described few systems of insulation resistance continuous measurement using an imposed DC test signal delivered by diode rectifiers. Drawbacks of this technique are pointed out and ways of these shortcomings removal are proposed. Methodology. An improved version of measuring circuit based on a single-phase diode rectifier is presented. Application of logometric measuring devices is suggested. Results. A new insulation resistance continuous measuring system is insensitive to network voltages variation and asymmetry. Modified circuit enables also implementation of a simple device for alarming the monitored network’s insulation deterioration and/or earth-fault protection. Originality. Formulas describing performance of diode rectifiers under asymmetrical supply have not been available so far. Both innovations (i.e. single-phase diode rectifier and logometric meter have not been applied widely for implementation of continuous insulation monitoring in live AC IT networks. Practical value. Use of both innovations will allow to eliminate unrequired dependence of measurement results on variable network voltages as well as their possible asymmetry. Exploitation of diode rectifier circuits for earth fault location is also possible.

  18. MODEL AND SIMULATION FOR A BRUSHLESS AC GENERATOR WITH A ROTARY RECTIFIER

    Institute of Scientific and Technical Information of China (English)

    田铭兴; 李群峰

    2004-01-01

    Objective For a brushless AC generator with a rotary rectifier, it is necessary and significant to model and simulate at normal and fault operation states. Methods Two new concepts, namely, Simulink signals and PSB(Power System Blockset) variables, are proposed, and the difference between the two concepts is clarified. Based on the new model for synchronous machines[1], a simulation model for a brushless AC generator with a rotary rectifier is constructed by Matlab/Simulink/PSB. This new model, which has a speed input terminal and an exciting voltage input one, can simulate the real electrical characters and direct mechanical connection between two synchronous machines perfectly. The rotary rectifier is a three-phase full-wave bridge rectifier which consists of six diodes. The model for the diodes is a macro-model which possesses much better accuracy than an ideal one of switches. Results Based on the present model, some simulation results such as exciting current waveform, phase current waveform and phase voltbge waveform are afftained at several operation conditions. Conclusion The simulation for a brushless AC generator with a rotary rectifier is demonstrated at normal and fault operation states, respectively. The results confirm the presented method.

  19. CyPPA, a positive modulator of small-conductance Ca(2+)-activated K(+) channels, inhibits phasic uterine contractions and delays preterm birth in mice.

    Science.gov (United States)

    Skarra, Dana V; Cornwell, Trudy; Solodushko, Viktoriya; Brown, Amber; Taylor, Mark S

    2011-11-01

    Organized uterine contractions, including those necessary for parturition, are dependent on calcium entry through voltage-gated calcium channels in myometrial smooth muscle cells. Recent evidence suggests that small-conductance Ca(2+)-activated potassium channels (K(Ca)2), specifically isoforms K(Ca)2.2 and 2.3, may control these contractions through negative feedback regulation of Ca(2+) entry. We tested whether selective pharmacologic activation of K(Ca)2.2/2.3 channels might depress uterine contractions, providing a new strategy for preterm labor intervention. Western blot analysis and immunofluorescence microscopy revealed expression of both K(Ca)2.2 and K(Ca)2.3 in the myometrium of nonpregnant (NP) and pregnant (gestation day 10 and 16; D10 and D16, respectively) mice. Spontaneous phasic contractions of isolated NP, D10, and D16 uterine strips were all suppressed by the K(Ca)2.2/2.3-selective activator CyPPA in a concentration-dependent manner. This effect was antagonized by the selective K(Ca)2 inhibitor apamin. Whereas CyPPA sensitivity was reduced in D10 and D16 versus NP strips (pIC(50) 5.33 ± 0.09, 4.64 ± 0.03, 4.72 ± 0.10, respectively), all contractions were abolished between 30 and 60 μM. Blunted contractions were associated with CyPPA depression of spontaneous Ca(2+) events in myometrial smooth muscle bundles. Augmentation of uterine contractions with oxytocin or prostaglandin F(2α) did not reduce CyPPA sensitivity or efficacy. Finally, in an RU486-induced preterm labor model, CyPPA significantly delayed time to delivery by 3.4 h and caused a 2.5-fold increase in pup retention. These data indicate that pharmacologic stimulation of myometrial K(Ca)2.2/2.3 channels effectively suppresses Ca(2+)-mediated uterine contractions and delays preterm birth in mice, supporting the potential utility of this approach in tocolytic therapies.

  20. New Active Queue Management Algorithm Based on Delay Jitter%基于时延抖动的主动队列管理算法

    Institute of Scientific and Technical Information of China (English)

    蔡珍珍; 周井泉

    2012-01-01

    With the rapid development of Interne!,resulted in the IP services growth rapidly and diversification. At the same time as the number of users increase dramatically, network traffic exploding, network congestion problems become more serious, so the quality of service (QoS) has become one of the world's research focuses. In order to achieve the relative performance of QoS,congestion control plays an important role, while the active queue management (Active Queue Management, AQM) mechanism is one of important means to achieve congestion control, AQM has become an attention and in-depth study of the hot issues in the field of IP network congestion control. Based on the fairness of the CHOKe, proposed a new delay jitter algorithm. The routers detect network congestion through the delay jitter and the average queue length .uses dynamic sampling hit and adaptive packet loss technology. The simulation experimental results show that the algorithm can protect the response stream effectively and improve the hit probability of non-response flow,improve the fairness of the algorithm.%随着Internet的迅速发展,致使IP业务的快速增长和多样化,用户数量急剧增加,网络流量呈爆炸式增长,网络拥塞问题变得越来越严重,因此服务质量(QoS)成为了当今世界研究热点之一.为了能达到相对的QoS的性能指标,拥塞控制发挥着相当重要的作用,而主动式队列管理(Active Queue Management,AQM)机制又是实现拥塞控制的重要手段之一,AQM成为了IP网络拥塞控制研究领域中备受关注和深入研究的热点问题.文中在增强CHOKe算法的公平性上,提出一种新的基于时延抖动的AQM算法-CZ-CHOKe.路由器通过时延抖动和队列的平均队长检测网络拥塞,同时采用动态采样击中和自适应丢包技术.仿真结果表明,该算法能有效地保护响应流,提高非响应流的击中概率,提高其算法的公平性.

  1. Measuring information-transfer delays.

    Directory of Open Access Journals (Sweden)

    Michael Wibral

    Full Text Available In complex networks such as gene networks, traffic systems or brain circuits it is important to understand how long it takes for the different parts of the network to effectively influence one another. In the brain, for example, axonal delays between brain areas can amount to several tens of milliseconds, adding an intrinsic component to any timing-based processing of information. Inferring neural interaction delays is thus needed to interpret the information transfer revealed by any analysis of directed interactions across brain structures. However, a robust estimation of interaction delays from neural activity faces several challenges if modeling assumptions on interaction mechanisms are wrong or cannot be made. Here, we propose a robust estimator for neuronal interaction delays rooted in an information-theoretic framework, which allows a model-free exploration of interactions. In particular, we extend transfer entropy to account for delayed source-target interactions, while crucially retaining the conditioning on the embedded target state at the immediately previous time step. We prove that this particular extension is indeed guaranteed to identify interaction delays between two coupled systems and is the only relevant option in keeping with Wiener's principle of causality. We demonstrate the performance of our approach in detecting interaction delays on finite data by numerical simulations of stochastic and deterministic processes, as well as on local field potential recordings. We also show the ability of the extended transfer entropy to detect the presence of multiple delays, as well as feedback loops. While evaluated on neuroscience data, we expect the estimator to be useful in other fields dealing with network dynamics.

  2. Macrophage peroxisome proliferator-activated receptor γ deficiency delays skin wound healing through impairing apoptotic cell clearance in mice.

    Science.gov (United States)

    Chen, H; Shi, R; Luo, B; Yang, X; Qiu, L; Xiong, J; Jiang, M; Liu, Y; Zhang, Z; Wu, Y

    2015-01-15

    Skin wound macrophages are key regulators of skin repair and their dysfunction causes chronic, non-healing skin wounds. Peroxisome proliferator-activated receptor gamma (PPARγ) regulates pleiotropic functions of macrophages, but its contribution in skin wound healing is poorly defined. We observed that macrophage PPARγ expression was upregulated during skin wound healing. Furthermore, macrophage PPARγ deficiency (PPARγ-knock out (KO)) mice exhibited impaired skin wound healing with reduced collagen deposition, angiogenesis and granulation formation. The tumor necrosis factor alpha (TNF-α) expression in wounds of PPARγ-KO mice was significantly increased and local restoration of TNF-α reversed the healing deficit in PPARγ-KO mice. Wound macrophages produced higher levels of TNF-α in PPARγ-KO mice compared with control. In vitro, the higher production of TNF-α by PPARγ-KO macrophages was associated with impaired apoptotic cell clearance. Correspondingly, increased apoptotic cell accumulation was found in skin wound of PPARγ-KO mice. Mechanically, peritoneal and skin wound macrophages expressed lower levels of various phagocytosis-related molecules. In addition, PPARγ agonist accelerated wound healing and reduced local TNF-α expression and wound apoptotic cells accumulation in wild type but not PPARγ-KO mice. Therefore, PPARγ has a pivotal role in controlling wound macrophage clearance of apoptotic cells to ensure efficient skin wound healing, suggesting a potential new therapeutic target for skin wound healing.

  3. Mulifunctional Dendritic Emitter: Aggregation-Induced Emission Enhanced, Thermally Activated Delayed Fluorescent Material for Solution-Processed Multilayered Organic Light-Emitting Diodes

    Science.gov (United States)

    Matsuoka, Kenichi; Albrecht, Ken; Yamamoto, Kimihisa; Fujita, Katsuhiko

    2017-01-01

    Thermally activated delayed fluorescence (TADF) materials emerged as promising light sources in third generation organic light-emitting diodes (OLED). Much effort has been invested for the development of small molecular TADF materials and vacuum process-based efficient TADF-OLEDs. In contrast, a limited number of solution processable high-molecular weight TADF materials toward low cost, large area, and scalable manufacturing of solution processed TADF-OLEDs have been reported so far. In this context, we report benzophenone-core carbazole dendrimers (GnB, n = generation) showing TADF and aggregation-induced emission enhancement (AIEE) properties along with alcohol resistance enabling further solution-based lamination of organic materials. The dendritic structure was found to play an important role for both TADF and AIEE activities in the neat films. By using these multifunctional dendritic emitters as non-doped emissive layers, OLED devices with fully solution processed organic multilayers were successfully fabricated and achieved maximum external quantum efficiency of 5.7%.

  4. The Effectiveness of Direct Instruction Flashcards with Guided Practice Activities to Instruct Two Elementary Students Diagnosed with Autism Spectrum Disorder and Delays in Pre-Academics and Communication

    Directory of Open Access Journals (Sweden)

    Cheryl Gould

    2013-07-01

    Full Text Available The purpose of the study was to evaluate the effectiveness of Direct Instruction (DI flashcards in combination with guided practice activities to instruct two elementary male students diagnosed with Autism Spectrum Disorder. Both students had delays in pre-academics and communication. The study was conducted within a designed instruction classroom at a public school in the Pacific Northwest. The researcher’s goal for the 7 and 9 year-olds was to master the names and sounds of the 18 most common lowercase letters of the alphabet and to generalize the newly acquired knowledge across settings and instructors. Throughout the study, a token economy system using pennies, stickers, or stamps was utilized in combination with specific praise to reinforce positive behaviors and focus. Participant 1’s performance for identifying lowercase letters improved by 19% and mastered Set 1. For sounds, Participant 1’ s performance slightly increased by 12%. The DI flashcards in combination with the guided practice activities intervention proved to be ineffective for Participant 2 for sounds and lowercase letters.

  5. Information in small neuronal ensemble activity in the hippocampal CA1 during delayed non-matching to sample performance in rats

    Directory of Open Access Journals (Sweden)

    Takahashi Susumu

    2009-09-01

    Full Text Available Abstract Background The matrix-like organization of the hippocampus, with its several inputs and outputs, has given rise to several theories related to hippocampal information processing. Single-cell electrophysiological studies and studies of lesions or genetically altered animals using recognition memory tasks such as delayed non-matching-to-sample (DNMS tasks support the theories. However, a complete understanding of hippocampal function necessitates knowledge of the encoding of information by multiple neurons in a single trial. The role of neuronal ensembles in the hippocampal CA1 for a DNMS task was assessed quantitatively in this study using multi-neuronal recordings and an artificial neural network classifier as a decoder. Results The activity of small neuronal ensembles (6-18 cells over brief time intervals (2-50 ms contains accurate information specifically related to the matching/non-matching of continuously presented stimuli (stimulus comparison. The accuracy of the combination of neurons pooled over all the ensembles was markedly lower than those of the ensembles over all examined time intervals. Conclusion The results show that the spatiotemporal patterns of spiking activity among cells in the small neuronal ensemble contain much information that is specifically useful for the stimulus comparison. Small neuronal networks in the hippocampal CA1 might therefore act as a comparator during recognition memory tasks.

  6. Delay Computation Using Fuzzy Logic Approach

    Directory of Open Access Journals (Sweden)

    Ramasesh G. R.

    2012-10-01

    Full Text Available The paper presents practical application of fuzzy sets and system theory in predicting delay, with reasonable accuracy, a wide range of factors pertaining to construction projects. In this paper we shall use fuzzy logic to predict delays on account of Delayed supplies and Labor shortage. It is observed that the project scheduling software use either deterministic method or probabilistic method for computation of schedule durations, delays, lags and other parameters. In other words, these methods use only quantitative inputs leaving-out the qualitative aspects associated with individual activity of work. The qualitative aspect viz., the expertise of the mason or the lack of experience can have a significant impact on the assessed duration. Such qualitative aspects do not find adequate representation in the Project Scheduling software. A realistic project is considered for which a PERT chart has been prepared using showing all the major activities in reasonable detail. This project has been periodically updated until its completion. It is observed that some of the activities are delayed due to extraneous factors resulting in the overall delay of the project. The software has the capability to calculate the overall delay through CPM (Critical Path Method when each of the activity-delays is reported. We shall now demonstrate that by using fuzzy logic, these delays could have been predicted well in advance.

  7. Facilitating tolerance of delayed reinforcement during functional communication training.

    Science.gov (United States)

    Fisher, W W; Thompson, R H; Hagopian, L P; Bowman, L G; Krug, A

    2000-01-01

    Few clinical investigations have addressed the problem of delayed reinforcement. In this investigation, three individuals whose destructive behavior was maintained by positive reinforcement were treated using functional communication training (FCT) with extinction (EXT). Next, procedures used in the basic literature on delayed reinforcement and self-control (reinforcer delay fading, punishment of impulsive responding, and provision of an alternative activity during reinforcer delay) were used to teach participants to tolerate delayed reinforcement. With the first case, reinforcer delay fading alone was effective at maintaining low rates of destructive behavior while introducing delayed reinforcement. In the second case, the addition of a punishment component reduced destructive behavior to near-zero levels and facilitated reinforcer delay fading. With the third case, reinforcer delay fading was associated with increases in masturbation and head rolling, but prompting and praising the individual for completing work during the delay interval reduced all problem behaviors and facilitated reinforcer delay fading.

  8. 柔性基础主动隔振系统的缩聚建模和时滞问题研究%Dynamic reduction modeling and time delay for an active vibration isolation system with flexible base

    Institute of Scientific and Technical Information of China (English)

    宋攀; 董兴建; 孟光

    2012-01-01

    以复杂柔性耦合主动隔振系统为对象,研究其动力学建模和时滞主动控制问题.考虑筏架和基础的弹性,建立浮筏系统的有限元模型,并基于超单元动力缩聚技术,把系统的有限元模型在物理空间中进行减缩.考虑作动器的时滞效应,建立系统的时滞主动控制模型,对系统的最大时滞量和控制器的时滞稳定性进行了数值研究.数值计算表明,主动控制中有必要考虑时滞因素以避免失稳,所提出的方法易于保证控制系统的性能和稳定性.%An elastic vibration active isolation system was taken as an object and its dynamic modeling and time delay active control problem were studied. Considering the flexibility of its raft and foundation, the finite element model of a floating raft system was built. Based on the super-element dynamic condensation technology, the finite element model was reduced in physical space. Considering the time delay effect of actuators, the time delay active control model was established and the maximum time delay of the system and the time delay stability of the controller were studied numerically. Numerical calculations showed that it is necessary to consider the time delay factor for the active control to avoid instability, the proposed method is easy to ensure the control system performance and stability.

  9. Feedback Linearization and Sliding Mode Control for VIENNA Rectifier Based on Differential Geometry Theory

    Directory of Open Access Journals (Sweden)

    Xiang Lu

    2015-01-01

    Full Text Available Aiming at the nonlinear characteristics of VIENNA rectifier and using differential geometry theory, a dual closed-loop control strategy is proposed, that is, outer voltage loop using sliding mode control strategy and inner current loop using feedback linearization control strategy. On the basis of establishing the nonlinear mathematical model of VIENNA rectifier in d-q synchronous rotating coordinate system, an affine nonlinear model of VIENNA rectifier is established. The theory of feedback linearization is utilized to linearize the inner current loop so as to realize the d-q axis variable decoupling. The control law of outer voltage loop is deduced by utilizing sliding mode control and index reaching law. In order to verify the feasibility of the proposed control strategy, simulation model is built in simulation platform of Matlab/Simulink. Simulation results verify the validity of the proposed control strategy, and the controller has a strong robustness in the case of parameter variations or load disturbances.

  10. Towards a 30kW/liter, Three-Phase Unity Power Factor Rectifier

    Science.gov (United States)

    Round, Simon; Karutz, Philipp; Heldwein, Marcelo; Kolar, Johann W.

    In this paper, a forced air-cooled, 400kHz, 10kW Vienna Rectifier with a power density of 8.5kW/liter is presented. To further improve the power density, the switching frequency is increased to reduce the EMI filter volume. A design for an 18.5kW/liter, 2.5MHz rectifier is proposed. By using today's technology, it is calculated that the maximum power density for a forced air-cooled and water-cooled rectifier is 20.8kW/liter and 24kW/liter respectively. To achieve 30kW/liter, improvements must be made in passive component material properties, reducing semiconductor losses and improving the cooling system.

  11. Theoretical study on the rectifying performance of organoimido derivatives of hexamolybdates.

    Science.gov (United States)

    Wen, Shizheng; Yang, Guochun; Yan, Likai; Li, Haibin; Su, Zhongmin

    2013-02-25

    We design a new type of molecular diode, based on the organoimido derivatives of hexamolybdates, by exploring the rectifying performances using density functional theory combined with the non-equilibrium Green's function. Asymmetric current-voltage characteristics were obtained for the models with an unexpected large rectification ratio. The rectifying behavior can be understood by the asymmetrical shift of the transmission peak observed under different polarities. It is interesting to find that the preferred electron-transport direction in our studied system is different from that of the organic D-bridge-A system. The results show that the studied organic-inorganic hybrid systems have an intrinsically robust rectifying ratio, which should be taken into consideration in the design of the molecular diodes.

  12. Initial Rotor Position Estimation of Half-Wave Rectified Brushless Synchronous Motor

    Science.gov (United States)

    Abe, Takashi; Oyama, Jun; Higuchi, Tsuyoshi

    This paper presents an initial rotor position estimation of Half-Wave Rectified Brushless Synchronous Motor. In the previous paper, we proposed this motor as AC servo motor, which is based on the half-wave rectified brushless excitation principle. The basic principle of this estimation technique utilizes the dependence of inductance on the rotor position. The bias frequency component of half-Wave rectified brushless excitation is used to estimate the rotor position error. The magnetic pole is discriminated by the switching condition of the diode inserted into the rotor field winding. This estimation technique is confirmed by simulation include inverter circuit, control program and motor model. Finally, the effectiveness of the proposed estimation technique has been verified by experiments.

  13. A Novel Unit Power Factor Rectifier Based on Three-phase Digital PLL

    Directory of Open Access Journals (Sweden)

    Xuegui Zhu

    2013-07-01

    Full Text Available A novel three-phase phase-locked loop solution is proposed based on D-Q transformation aiming at the AC-DC rectifier with high efficiency and high power factor. The phase-locked loop is implemented digitally using the Xilinx blockset integrated with Matlab/Simulink. The three-phase digital phase-locked loop (TDPLL is elaborately designed with the parameters defined in detail. The AC-DC converter (rectifier model with the TDPLL is built and simulated in the high-speed VHS-ADC simulation platform from Canada. The simulation and test results show the TDPLL is locked right after the different three-phase voltage disturbances and very suitable for control of the rectifier with high parallelism through space vector pulse width modulation (SVPWM.  

  14. G protein-coupled inwardly rectifying potassium channels in dorsal root ganglion neurons

    Institute of Scientific and Technical Information of China (English)

    Xiao-fei GAO; Hai-lin ZHANG; Zhen-dong YOU; Chang-lin LU; Cheng HE

    2007-01-01

    Aim: G protein-coupled inwardly rectifying potassium channels (GIRK) are important for neuronal signaling and membrane excitability. In the present study, we intend to find whether GIRK channels express functionally in adult rat dorsal root ganglion (DRG) neurons. Methods: We used RT-PCR to detect mRNA for4 subunits of GIRK in the adult DRG. The whole-cell patch clamp recording was used to confirm GIRK channels functionally expressed. Results: The mRNA for the 4 subunits of GIRK were detected in the adult DRG. GTPγS enhanced inwardly rectifying potassium (K+) currents of the DRG neurons, while Ba2+inhibited such currents. Furthermore, the GIRK channels were shown to be coupled to the GABAB receptor, a member of the G protein-coupled receptor family, as baclofen increased the inwardly rectifying K+ currents. Conclusion: GIRK channels are expressed and functionally coupled with GABAB receptors in adult rat DRG neurons.

  15. Does lindane (gamma-hexachlorocyclohexane) increase the rapid delayed rectifier outward K+ current (IKr) in frog atrial myocytes?

    OpenAIRE

    Sauviat, Martin-Pierre; Colas, Anthony; Pages, Nicole

    2002-01-01

    BACKGROUND: The effects of lindane, a gamma-isomer of hexachlorocyclohexane, were studied on transmembrane potentials and currents of frog atrial heart muscle using intracellular microelectrodes and the whole cell voltage-clamp technique. RESULTS: Lindane (0.34 microM to 6.8 microM) dose-dependently shortened the action potential duration (APD). Under voltage-clamp conditions, lindane (1.7 microM) increased the amplitude of the outward current (Iout) which developed in Ringer solution contain...

  16. Relationship between evolving epileptiform activity and delayed loss of mitochondrial activity after asphyxia measured by near-infrared spectroscopy in preterm fetal sheep.

    Science.gov (United States)

    Bennet, L; Roelfsema, V; Pathipati, P; Quaedackers, J S; Gunn, A J

    2006-04-01

    Early onset cerebral hypoperfusion after birth is highly correlated with neurological injury in premature infants, but the relationship with the evolution of injury remains unclear. We studied changes in cerebral oxygenation, and cytochrome oxidase (CytOx) using near-infrared spectroscopy in preterm fetal sheep (103-104 days of gestation, term is 147 days) during recovery from a profound asphyxial insult (n= 7) that we have shown produces severe subcortical injury, or sham asphyxia (n= 7). From 1 h after asphyxia there was a significant secondary fall in carotid blood flow (P < 0.001), and total cerebral blood volume, as reflected by total haemoglobin (P < 0.005), which only partially recovered after 72 h. Intracerebral oxygenation (difference between oxygenated and deoxygenated haemoglobin concentrations) fell transiently at 3 and 4 h after asphyxia (P < 0.01), followed by a substantial increase to well over sham control levels (P < 0.001). CytOx levels were normal in the first hour after occlusion, was greater than sham control values at 2-3 h (P < 0.05), but then progressively fell, and became significantly suppressed from 10 h onward (P < 0.01). In the early hours after reperfusion the fetal EEG was highly suppressed, with a superimposed mixture of fast and slow epileptiform transients; overt seizures developed from 8 +/- 0.5 h. These data strongly indicate that severe asphyxia leads to delayed, evolving loss of mitochondrial oxidative metabolism, accompanied by late seizures and relative luxury perfusion. In contrast, the combination of relative cerebral deoxygenation with evolving epileptiform transients in the early recovery phase raises the possibility that these early events accelerate or worsen the subsequent mitochondrial failure.

  17. The Right Delay

    NARCIS (Netherlands)

    Datadien, A.H.R.; Haselager, W.F.G.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Axonal conduction delays should not be ignored in simulations of spiking neural networks. Here it is shown that by using axonal conduction delays, neurons can display sensitivity to a specific spatio-temporal spike pattern. By using delays that complement the firing times in a pattern, spikes can ar

  18. Microrectenna: A Terahertz Antenna and Rectifier on a Chip

    Science.gov (United States)

    Siegel, Peter

    2007-01-01

    A microrectenna that would operate at a frequency of 2.5 THz has been designed and partially fabricated. The circuit is intended to be a prototype of an extremely compact device that could be used to convert radio-beamed power to DC to drive microdevices (see Figure 1). The microrectenna (see Figure 2) circuit consists of an antenna, a diode rectifier and a DC output port. The antenna consists of a twin slot array in a conducting ground plane (denoted the antenna ground plane) over an enclosed quarter-wavelength-thick resonant cavity (denoted the reflecting ground plane). The circuit also contains a planar high-frequency low-parasitic Schottky-barrier diode, a low-impedance microstrip transmission line, capacitors, and contact beam leads. The entire 3-D circuit is fabricated monolithically from a single GaAs wafer. The resonant cavity renders the slot radiation pattern unidirectional with a half-power beam width of about 65. A unique metal mesh on the rear of the wafer forms the backplate for the cavity but allows the GaAs to be wet etched from the rear surface of the twin slot antennas and ground plane. The beam leads protrude past the edge of the chip and are used both to mount the microrectenna and to make the DC electrical connection with external circuitry. The antenna ground plane and the components on top of it are formed on a 2- m thick GaAs membrane that is grown in the initial wafer MBE (molecular beam epitaxy) process. The side walls of the antenna cavity are not metal coated and, hence, would cause some loss of power; however, the relatively high permittivity (epsilon=13) of the GaAs keeps the cavity modes well confined, without the usual surface-wave losses associated with thick dielectric substrates. The Schottky-barrier diode has the usual submicron dimensions associated with THz operation and is formed in a mesa process above the antenna ground plane. The diode is connected at the midpoint of a microstrip transmission line, which is formed on 1- m

  19. Eccentric exercise and delayed onset muscle soreness of the quadriceps induce adjustments in agonist-antagonist activity, which are dependent on the motor task.

    Science.gov (United States)

    Vila-Chã, C; Hassanlouei, H; Farina, D; Falla, D

    2012-02-01

    This study investigates the effects of eccentric exercise and delayed onset muscle soreness (DOMS) of the quadriceps on agonist-antagonist activity during a range of motor tasks. Ten healthy volunteers (age, mean ± SD, 24.9 ± 3.2 years) performed maximum voluntary contractions (MVC) and explosive isometric contractions of the knee extensors followed by isometric contractions at 2.5, 5, 10, 15, 20, and 30% MVC at baseline, immediately after and 24 h after eccentric exercise of the quadriceps. During each task, force of the knee extensors and surface EMG of the vasti and hamstrings muscles were recorded concurrently. Rate of force development (RFD) was computed from the explosive isometric contraction, and the coefficient of variation of the force (CoV) signal was estimated from the submaximal contractions. Twenty-four hours after exercise, the subjects rated their perceived pain intensity as 4.1 ± 1.2 (score out of 10). The maximum RFD and MVC of the knee extensors was reduced immediately post- and 24 h after eccentric exercise compared to baseline (average across both time points: 19.1 ± 17.1% and 11.9 ± 9.8% lower, respectively, P eccentric exercise (up to 66% higher than baseline, P exercise during the presence of DOMS (P exercise and was accompanied by increased antagonist EMG for the explosive contraction only. On the contrary, reduced force steadiness was accompanied by a general increase in EMG amplitude of the vasti muscles and was accompanied by increased antagonist activity, but only at higher force levels (>15% MVC). This study shows that eccentric exercise and subsequent DOMS of the quadriceps reduce the maximal force, rate of force development and force steadiness of the knee extensors, and is accompanied by different adjustments of agonist and antagonist muscle activities.

  20. Observation of three-level rectified dipole forces acting on trapped atoms

    Science.gov (United States)

    Grove, T. T.; Duncan, B. C.; Sanchez-Villicana, V.; Gould, P. L.

    1995-06-01

    We have observed rectified dipole forces acting on three-level atoms in the cascade configuration. Laser cooled and trapped rubidium atoms are illuminated with an intense bichromatic standing wave (780 and 776 nm) tuned near resonance with the 5S1/2-->5P3/2-->5D5/2 transitions. The resulting rectified forces produce periodic potential wells (71-μm period), which localize the cold atoms. Experimental results are in reasonable agreement with theoretical predictions. These forces may be useful in atom optics and laser traps.

  1. New Squarer Circuits and a Current-Mode Full-Wave Rectifier Topology Suitable for Integration

    Directory of Open Access Journals (Sweden)

    S. Minaei

    2010-12-01

    Full Text Available In this paper, three squarer configurations and a current-mode (CM full-wave rectifier circuit are suggested. The first and second squarer configurations respectively use two PMOS and two NMOS transistors while the third one employs three PMOS and one NMOS transistors. A CM full-wave rectifier with high output impedance current is developed. All of the proposed circuits provide several advantages such as low number of components and less power consumption. The proposed circuits are simulated using SPICE program to demonstrate their performance and workability.

  2. A Simple Method for Reducing the Transient Oscillation in Single-Phase Buck Rectifiers

    Science.gov (United States)

    Wakakuwa, Yukihiro; Motegi, Shin-Ich; Yoshida, Toshiya; Miyashita, Osamu

    The single-phase buck rectifier has several advantages, such as the controllability of lower dc output voltages, and negligible inrush input-current at start-up. However, the rectifier requires an LC-filter connected on the input side of the switching device to absorb the harmonics caused by the on and off behavior. The LC-filter involves an LC resonance in transient states. To solve this problem, a suppression approach using only a series RLC circuit, which selectively acts as a damping at around the resonant frequency, is proposed. Simulation and experimental results confirm the validity of this method.

  3. Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation

    Directory of Open Access Journals (Sweden)

    MILOUD, Y.

    2010-08-01

    Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load�s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.

  4. Activation of human ether-a-go-go-related gene potassium channels by the diphenylurea 1,3-bis-(2-hydroxy-5-trifluoromethyl-phenyl)-urea (NS1643)

    DEFF Research Database (Denmark)

    Hansen, Rie Schultz; Diness, Thomas Goldin; Christ, Torsten

    2005-01-01

    repolarization current could be a new antiarrhythmic principle, because it possibly would attenuate afterdepolarizations, ischemic leak currents, and reentry phenomena. Repolarization of the cardiac myocytes is crucially dependent on the late rapid delayed rectifier current (I(Kr)) conducted by ether...... microM NS1643 activated I(Kr) and significantly decreased the action potential duration to 65% of the control values. The effect could be reverted by application of the specific HERG channel inhibitor 4'-[[1-[2-(6-methyl-2-pyridyl)ethyl]-4-piperidinyl]carbonyl]-methanesulfonanilide (E-4031) at 100 n...

  5. A Fuzzy-Logic-Based Controller for Three-Phase PWM Rectifier With Unity Power Factor Operation

    Directory of Open Access Journals (Sweden)

    A. Bouafia

    2008-03-01

    Full Text Available In this paper, direct power control (DPC of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The control technique is built upon the ideas of the well known direct torque control (DTC for induction motors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The proposed fuzzy logic controller presents the advantage to be based on linguistic description and does not require a mathematical model of the system. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The simulation results show that the designed fuzzy controller has a good dynamic behavior, a good rejection of impact load disturbance, and is very robust.

  6. Ideal Molecular Design of Blue Thermally Activated Delayed Fluorescent Emitter for High Efficiency, Small Singlet-Triplet Energy Splitting, Low Efficiency Roll-Off, and Long Lifetime.

    Science.gov (United States)

    Lee, Dong Ryun; Choi, Jeong Min; Lee, Chil Won; Lee, Jun Yeob

    2016-09-07

    Highly efficient thermally activated delayed fluorescent (TADF) emitters, 5-(2-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-5H-benzofuro[3,2-c]carbazole (oBFCzTrz), 5-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-5H-benzofuro[3,2-c]carbazole (mBFCzTrz), and 5-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)-5H-benzofuro[3,2-c]carbazole (pBFCzTrz), were synthesized to study the effects of ortho-, meta-, and para- linkages between donor and acceptor moieties. oBFCzTrz having ortho- linked donor and acceptor moieties showed smaller singlet-triplet energy gap, shorter excited state lifetime, and higher photoluminescence quantum yield than mBFCzTrz and pBFCzTrz which are interconnected by meta- and para- positions. The TADF device using oBFCzTrz as a blue emitter exhibited high external quantum efficiency over 20%, little efficiency roll-off, and long device lifetime.

  7. Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells.

    Science.gov (United States)

    Ke, Ruian; Lewin, Sharon R; Elliott, Julian H; Perelson, Alan S

    2015-10-01

    Recent efforts to cure human immunodeficiency virus type-1 (HIV-1) infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

  8. Reliable Prediction with Tuned Range-Separated Functionals of the Singlet-Triplet Gap in Organic Emitters for Thermally Activated Delayed Fluorescence (TADF)

    KAUST Repository

    Sun, Haitao

    2015-07-09

    The thermally activated delayed fluorescence (TADF) mechanism has recently attracted much interest in the field of organic light-emitting diodes (OLEDs). TADF relies on the presence of a very small energy gap between the lowest singlet and triplet excited states. Here, we demonstrate that time-dependent density functional theory (TD-DFT) in the Tamm-Dancoff Approximation can be very successful in the calculations of the lowest singlet and triplet excitation energies and the corresponding singlet-triplet gap when using nonempirically tuned range-separated functionals. Such functionals provide very good estimates in a series of 17 molecules used in TADF-based OLED devices, with mean absolute deviations of 0.15 eV for the vertical singlet excitation energies and 0.09 eV [0.07 eV] for the adiabatic [vertical] singlet-triplet energy gaps as well as low relative errors and high correlation coefficients compared to the corresponding experimental values. They significantly outperform conventional functionals, a feature which is rationalized on the basis of the amount of exact-exchange included and the delocalization error. The present work provides a reliable theoretical tool for the prediction and development of novel TADF-based materials with low singlet-triplet energetic splittings.

  9. Modeling the Effects of Vorinostat In Vivo Reveals both Transient and Delayed HIV Transcriptional Activation and Minimal Killing of Latently Infected Cells.

    Directory of Open Access Journals (Sweden)

    Ruian Ke

    2015-10-01

    Full Text Available Recent efforts to cure human immunodeficiency virus type-1 (HIV-1 infection have focused on developing latency reversing agents as a first step to eradicate the latent reservoir. The histone deacetylase inhibitor, vorinostat, has been shown to activate HIV RNA transcription in CD4+ T-cells and alter host cell gene transcription in HIV-infected individuals on antiretroviral therapy. In order to understand how latently infected cells respond dynamically to vorinostat treatment and determine the impact of vorinostat on reservoir size in vivo, we have constructed viral dynamic models of latency that incorporate vorinostat treatment. We fitted these models to data collected from a recent clinical trial in which vorinostat was administered daily for 14 days to HIV-infected individuals on suppressive ART. The results show that HIV transcription is increased transiently during the first few hours or days of treatment and that there is a delay before a sustained increase of HIV transcription, whose duration varies among study participants and may depend on the long term impact of vorinostat on host gene expression. Parameter estimation suggests that in latently infected cells, HIV transcription induced by vorinostat occurs at lower levels than in productively infected cells. Furthermore, the estimated loss rate of transcriptionally induced cells remains close to baseline in most study participants, suggesting vorinostat treatment does not induce latently infected cell killing and thus reduce the latent reservoir in vivo.

  10. TOXIC ACTIVITY AND DELAYED EFFECTS OF FIVE BOTANICAL OILS ON THE FOLLOWING GENERATIONS OF AGROTIS IPSILON (HUFNAGEL) (INSECTA: LEPIDOPTERA: NOCTUIDAE) AFTER PARENTS TREATMENT.

    Science.gov (United States)

    Mesbah, H A; El-Sayed, N A; El-Kady, M B; Mourad, A K; Kordy, A M; Henaidy, Z M

    2014-01-01

    The present study is carried out to evaluate the toxic efficiency and delayed effects of five botanical oils on the greasy cut worm Agrotis ipsilon (Lepidoptera: Noctuidae), as a trial for the attainment of a possible use of an alternative safe and effective phytochemicals against the insect-pest. So as to minimize or prevent the repeated usage of conventional insecticides, then reduce the environmental pollution as well as the occurring hazards to man and domestic animal due to the use of the pesticides alone. Four tested concentrations (0.5, 1.0, 1.5 and 2.5% v/v) from each of camphor, red basil, menthol, rose and anise oils, were bioassayed by treating the offered castor oil bean leaves, to the 4th instar larvae along 48h, under the laboratory higrothermic conditions of 25±2 °C and 65±5% R.H. The obtained results showed that the five tested oils were found to have more or less toxic activity and drastic effects on the inspected parameters of fitness components of the treated parent generation of the insect, in particular, pupae, emerged adult moths and laid eggs/female. In this respect camphor and red basil oils were highly effective, followed by menthol oil, anise oil and the least effective one was rose oil. Moreover, the assessed unprofitable delayed effects on the going on of the biological performance within the treated insects showed the adverse effects on the fitness components of the consequent generations (fs) post (p) one treatment with each of the bioassyed oils. The prevalence of adverse effects and disturbance in the going on biological performance through the period of (p) generation; which is followed by the distinct failure of insect development in (f1) generation were recorded for each of the tested menthol oil at 0.5 and 1.5% (v/v); camphor oil at 1.5 and 2.5% and red basil oil at 2.5% (v/v). While anise and rose oils were somewhat less efficient causing the distinct failure of the following generations up to the 3rd and/or the 6th ones

  11. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  12. 车辆电动静液压作动器的半主动悬架时滞补偿控制%Time Delay Compensation Control of Semi-active Suspension with Vehicle Electro-hydrostatic Actuator

    Institute of Scientific and Technical Information of China (English)

    寇发荣; 范养强; 张传伟; 杜嘉峰; 王哲

    2016-01-01

    为了改善车辆行驶的平顺性和操纵稳定性,设计了一种基于电动静液压作动器(EHA)的车辆半主动悬架结构。进行了EHA作动器的性能试验分析,建立了 EHA半主动悬架的键合图模型,计算了EHA半主动悬架系统的临界时滞,分析了时滞对 EHA半主动悬架幅频特性和减振性能的影响,设计了Smith预估时滞补偿控制器,进行了 EHA 模糊控制半主动悬架的时滞补偿仿真分析。结果表明,EHA半主动悬架具有较好的阻尼可控性;然而随着时滞的增大,悬架系统会出现“轮跳”现象;在Smith时滞预估补偿控制下,EHA 半主动悬架的簧载质量加速度减小约30%,轮胎动载荷减小约20%。%To improve the ride comfort and stability of vehicles,a kind of the semi-active suspen-sion with EHA was designed and the mechanical property tests of the electro-hydrostatic actuator were completed.The bond graph models of the time delay fuzzy control for EHA semi-active suspen-sion were established.The critical time delay of the EHA semi-active suspension was calculated.The time delay impacts on the amplitude-frequency characteristics and vibration isolation properties were analyzed.The time delay fuzzy Smith predictive compensation controller was designed.The simulation analyses of the time delay compensation fuzzy control for the EHA semi-active suspension were done. The results show that the EHA semi-active suspension has good damping controllability.However, with the increase of time delay,the “j ump vibration”phenomenon happens to the suspension system. Under the time delay compensation fuzzy control of the EHA semi-active suspension,the sprung mass acceleration drops by about 30% and the tire dynamic load drops by about 20%.

  13. Dynamics of Nonlinear Time-Delay Systems

    CERN Document Server

    Lakshmanan, Muthusamy

    2010-01-01

    Synchronization of chaotic systems, a patently nonlinear phenomenon, has emerged as a highly active interdisciplinary research topic at the interface of physics, biology, applied mathematics and engineering sciences. In this connection, time-delay systems described by delay differential equations have developed as particularly suitable tools for modeling specific dynamical systems. Indeed, time-delay is ubiquitous in many physical systems, for example due to finite switching speeds of amplifiers in electronic circuits, finite lengths of vehicles in traffic flows, finite signal propagation times in biological networks and circuits, and quite generally whenever memory effects are relevant. This monograph presents the basics of chaotic time-delay systems and their synchronization with an emphasis on the effects of time-delay feedback which give rise to new collective dynamics. Special attention is devoted to scalar chaotic/hyperchaotic time-delay systems, and some higher order models, occurring in different bran...

  14. Activity of Palythoa caribaeorum Venom on Voltage-Gated Ion Channels in Mammalian Superior Cervical Ganglion Neurons

    Directory of Open Access Journals (Sweden)

    Fernando Lazcano-Pérez

    2016-05-01

    Full Text Available The Zoanthids are an order of cnidarians whose venoms and toxins have been poorly studied. Palythoa caribaeorum is a zoanthid commonly found around the Mexican coastline. In this study, we tested the activity of P. caribaeorum venom on voltage-gated sodium channel (NaV1.7, voltage-gated calcium channel (CaV2.2, the A-type transient outward (IA and delayed rectifier (IDR currents of KV channels of the superior cervical ganglion (SCG neurons of the rat. These results showed that the venom reversibly delays the inactivation process of voltage-gated sodium channels and inhibits voltage-gated calcium and potassium channels in this mammalian model. The compounds responsible for these effects seem to be low molecular weight peptides. Together, these results provide evidence for the potential use of zoanthids as a novel source of cnidarian toxins active on voltage-gated ion channels.

  15. The amplitude and inactivation properties of the delayed potassium currents are regulated by protein kinase activity in hair cells of the frog semicircular canals.

    Directory of Open Access Journals (Sweden)

    Marta Martini

    Full Text Available In hair cells dissected from the frog crista ampullaris, the combination of a calcium-dependent (IKCa and a purely voltage-dependent component (IKV gives rise to the delayed potassium current complex (IKD. These currents have been recently reported to display slow depolarization-induced inactivation and biphasic inactivation removal by hyperpolarization. The amplitude and inactivation kinetics of both IKCa and IKV are drastically modulated by a previously unrecognized mechanism of protein phosphorylation (sensitive to kinase inhibitors H89 and KT5823, which does not interfere with the transient potassium current (IA or the calcium current (ICa. IKD amplitude was stable in cells patched with pipettes containing 8 mM ATP or under perforated-patch; under these conditions, a 10 min treatment with 10 µM H89 or 1-10 µM KT5823 reduced IKD amplitude by a mean of 67% at +40 mV. Similarly affected was the isolated IKV component (ICa blocked with Cd(2+. Thus, a large potassium conductance can be activated by depolarization, but it is made available to the cell to a variable extent that depends on membrane potential and protein kinase activity. The total gKD ranged 4.6-44.0 nS in control cells, according to the level of steady-state inactivation, and was reduced to 1.4-2.7 nS after protein kinase inhibition. When sinusoidal membrane potential changes in the -70/-10 mV range were applied, to mimic receptor response to hair bundle deflection, IKD proved the main current dynamically activated and the only one regulated by PK: H89 decreased the total outward charge during each cycle by 60%. Phosphorylation appears to control both the amount of IKCa and IKV conductance activated by depolarization and the fraction thereof which can be rescued by removal of inactivation. The balance between the depolarizing transduction current and the repolarizing potassium current, and eventually the transmitter release at the cytoneural junction, are therefore modulated by a

  16. 延迟冷却对牛背最长肌中μ-calpain活性及嫩度的影响%Effect of Delay Chilling on μ-calpain Activities and the Tenderness of Bovine M.Iongissimus

    Institute of Scientific and Technical Information of China (English)

    胡鹏; 丁玉; 梁荣蓉; 罗欣

    2010-01-01

    μ-calpain activities and shear force values of bovine M.Iongissimus from Chinese Yellow crossbred bulls were analyzed,and the effect of delay chilling on μ-calpain activities and the tenderness of beef during postmortem aging were studied.The results showed that delay chilling significantly improved μ-calpain activities (P<0.05) and enhanced the tenderness of bovine M.Iongissimus during earlier aging periods compared with conventional chilling.But in later aging periods,delay chilling weakened the effect on the tenderness of beef because of premature consumption of μ-calpain.The experiment results confirmed that delay chilling improved the rate of postmortem aging of beef and remarkably enhanced the tenderness of beef through the effect of delay chilling on μ-calpain activities.%[目的]研究延迟冷却对牛背最长肌中μ-calpain活性及嫩度的影响,为进一步改善牛肉食用品质提供依据.[方法]测定中国杂交黄牛(鲁西黄牛x西门塔尔)牛背最长肌中μ-calpain活性及剪切力值,分析延迟冷却对牛背最长肌宰后成熟过程中μ-calpain活性及牛肉嫩度的影响.[结果]在宰后成熟早期,延迟冷却显著提高了μ-calpain的活性,提高了牛背最长肌的嫩度;成熟后期,由于μ-calpain被过早消耗,对牛肉的嫩化作用减弱.[结论]延迟冷却通过对μ-calpain活性的影响,改变了肉的成熟速度,显著改善了牛肉的嫩度.

  17. Performance improvement of three phase rectifier by employing electronic smoothing inductor

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben O.

    2014-01-01

    An electronic smoothing inductor (ESI) is very attractive circuit topology to improve power factor and to reduce the total harmonic distortions (THDs) of the ac mains current in a three phase diode bridge rectifier. The ESI reduces the low frequency ripples and controls the intermediate dc...

  18. Development of a 50-60 Hz thermally switched superconducting rectifier

    NARCIS (Netherlands)

    Shevchenko, O.A.; Kate, ten H.H.J.; Krooshoop, H.J.G.; Markovsky, N.V.; Mulder, G.B.J.

    1993-01-01

    A full-wave thermally switched superconducting rectifier, able to operate directly from the mains at the 50-60-Hz frequency, has been developed. Typical design output values of this device are a current of 300 A, a voltage of up to 1 V, an average power of up to 100 VA, and an efficiency better than

  19. Analysis of Three-Phase Rectifier Systems with Controlled DC-Link Current Under Unbalanced Grids

    DEFF Research Database (Denmark)

    Kumar, Dinesh; Davari, Pooya; Zare, Firuz

    2017-01-01

    Voltage unbalance is the most common disturbance in distribution networks, which give undesirable effects on many grid connected power electronics systems including Adjustable Speed Drive (ASD). Severe voltage unbalance can force three-phase rectifiers into almost single-phase operation, which de...

  20. AUTOMATION METHODS FOR FORMING AND RECTIFYING STIFFENED PARTS WITH ROLLING MACHINES

    Directory of Open Access Journals (Sweden)

    A.Ye. Pashkov

    2015-12-01

    Full Text Available To improve the capabilities of forming and rectifying stiffened parts, rolling as one of the implemented methods of local plastic deformation has been examined. The tools for edge and sheet rolling have been described. The methods of process automation have been developed.

  1. Measurements on power-conversion gain and noise ratio of the 1N26 crystal rectifiers

    NARCIS (Netherlands)

    Dymanus, A.; Bouwknegt, A.

    1960-01-01

    Measurements have been performed on power conversion gain G and noise ratio n of a number of 1N26 silicon rectifiers (Sylvania Co., U.S.A.) using well-known techniques. The noise ratio has been investigated both with microwave excitation (10−6-10−3 W at 24 GHz) and with DC-excitation by currents up

  2. Current Mode Full-Wave Rectifier Based on a Single MZC-CDTA

    Directory of Open Access Journals (Sweden)

    Neeta Pandey

    2013-01-01

    Full Text Available This paper presents a current mode full-wave rectifier based on single modified Z copy current difference transconductance amplifier (MZC-CDTA and two switches. The circuit is simple and is suitable for IC implementation. The functionality of the circuit is verified with SPICE simulation using 0.35 μm TSMC CMOS technology parameters.

  3. CMOS-Compatible Room-Temperature Rectifier Toward Terahertz Radiation Detection

    Science.gov (United States)

    Varlamava, Volha; De Amicis, Giovanni; Del Monte, Andrea; Perticaroli, Stefano; Rao, Rosario; Palma, Fabrizio

    2016-08-01

    In this paper, we present a new rectifying device, compatible with the technology of CMOS image sensors, suitable for implementing a direct-conversion detector operating at room temperature for operation at up to terahertz frequencies. The rectifying device can be obtained by introducing some simple modifications of the charge-storage well in conventional CMOS integrated circuits, making the proposed solution easy to integrate with the existing imaging systems. The rectifying device is combined with the different elements of the detector, composed of a 3D high-performance antenna and a charge-storage well. In particular, its position just below the edge of the 3D antenna takes maximum advantage of the high electric field concentrated by the antenna itself. In addition, the proposed structure ensures the integrity of the charge-storage well of the detector. In the structure, it is not necessary to use very scaled and costly technological nodes, since the CMOS transistor only provides the necessary integrated readout electronics. On-wafer measurements of RF characteristics of the designed junction are reported and discussed. The overall performances of the entire detector in terms of noise equivalent power (NEP) are evaluated by combining low-frequency measurements of the rectifier with numerical simulations of the 3D antenna and the semiconductor structure at 1 THz, allowing prediction of the achievable NEP.

  4. High Efficiency Three-phase Power Factor Correction Rectifier using Wide Band-Gap Devices

    DEFF Research Database (Denmark)

    Kouchaki, Alireza

    2016-01-01

    . Therefore, current controllers are also important to be investigated in this project. In this PhD research work, a comprehensive design of a two-level three-phase PFC rectifier using silicon-carbide (SiC) switches to achieve high efficiency is presented. The work is divided into two main parts: 1) Optimum...

  5. Zero sequence blocking transformers for multi-pulse rectifier in aerospace applications

    DEFF Research Database (Denmark)

    Yao, Wenli; Blaabjerg, Frede; Zhang, Xiaobin

    2014-01-01

    The power electronics technology plays an even more important role in the aerospace applications of More Electric Aircrafts (MEA). AutoTransformer Rectifier Units (ATRU) have been widely adopted in aircrafts due to its simplicity and reliability. In this paper, Zero Sequence Blocking Transformers...

  6. Connection of OWPPs to HVDC networks using VSCs and Diode Rectifiers: an Overview

    DEFF Research Database (Denmark)

    Saborío-Romano, Oscar; Bidadfar, Ali; Göksu, Ömer;

    This paper provides an overview of two technologies for connecting offshore wind power plants (offshore WPPs, OWPPs) to high-voltage direct current (HVDC) networks: voltage source converters (VSCs) and diode rectifiers (DRs). Current grid code requirements for the connection of such power plants...

  7. A Saturated Output Feedback Controller for the Three Phase Voltage Sourced Reversible Boost Type Rectifier

    NARCIS (Netherlands)

    Escobar, Gerardo; Ortega, Romeo; Schaft, Arjan J. van der

    1998-01-01

    In this article, we present a saturating controller to regulate the output voltage load in a three phase Boost type rectifier. The controller only needs the output voltage signal to be implemented. Moreover, by forcing the inductance currents to track desired suitable sinusoidal signals in phase wit

  8. Towards highly efficient red thermally activated delayed fluorescence materials by the control of intra-molecular π-π stacking interactions

    Science.gov (United States)

    Zhang, Yunge; Zhang, Dongdong; Cai, Minghan; Li, Yilang; Zhang, Deqiang; Qiu, Yong; Duan, Lian

    2016-03-01

    Thermally activated delayed fluorescence (TADF) materials have attracted much attention as they can achieve 100% theoretical internal quantum efficiency without using expensive noble metals. However, efficient red TADF emitters are hard to realize according to the energy gap law. Here, three donor-acceptor-donor type TADF emitters with the same acceptor of o-phthalodinitrile (PN) but different donors (9, 9-dimethyl-9, 10-dihydroacridine (DMAC), phenoxazine (PXZ), and phenothiazine (PTZ) for DMAC-PN, PXZ-PN, and PTZ-PN, respectively) have been synthesized, and it is observed that the performance of the emitters can be improved by reducing the intra-molecular π-π stacking. DMAC-PN with reduced intra-molecular π-π stacking shows a photoluminescence quantum yield (PLQY) of 20.2% in degassed toluene solution, much higher than those of PXZ-PN, and PTZ-PN (0.8%, 0.2%, respectively). An organic light-emitting diode (OLED) employing DMAC-PN doped into 4,4‧-bis(9H-carbazol-9-yl)biphenyl (CBP) as the emitting layer exhibits a maximum external quantum efficiency (EQE) of 10.2% with the emission peak at 564 nm. Moreover, when DMAC-PN is doped into a polar host, bis[2-(diphenylphosphino)phenyl] ether oxide (DPEPO), the OLED shows a large redshift of the emission maximum to 594 nm, while maintaining a peak EQE as high as 7.2%, indicating that efficient red TADF OLEDs can be fabricated by doping orange TADF emitters into hosts with proper polarity.

  9. Delayed emergence after anesthesia.

    Science.gov (United States)

    Tzabazis, Alexander; Miller, Christopher; Dobrow, Marc F; Zheng, Karl; Brock-Utne, John G

    2015-06-01

    In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

  10. hERG S4-S5 linker acts as a voltage-dependent ligand that binds to the activation gate and locks it in a closed state.

    Science.gov (United States)

    Malak, Olfat A; Es-Salah-Lamoureux, Zeineb; Loussouarn, Gildas

    2017-12-01

    Delayed-rectifier potassium channels (hERG and KCNQ1) play a major role in cardiac repolarization. These channels are formed by a tetrameric pore (S5-S6) surrounded by four voltage sensor domains (S1-S4). Coupling between voltage sensor domains and the pore activation gate is critical for channel voltage-dependence. However, molecular mechanisms remain elusive. Herein, we demonstrate that covalently binding, through a disulfide bridge, a peptide mimicking the S4-S5 linker (S4-S5L) to the channel S6 C-terminus (S6T) completely inhibits hERG. This shows that channel S4-S5L is sufficient to stabilize the pore activation gate in its closed state. Conversely, covalently binding a peptide mimicking S6T to the channel S4-S5L prevents its inhibiting effect and renders the channel almost completely voltage-independent. This shows that the channel S4-S5L is necessary to stabilize the activation gate in its closed state. Altogether, our results provide chemical evidence that S4-S5L acts as a voltage-controlled ligand that binds S6T to lock the channel in a closed state, elucidating the coupling between voltage sensors and the gate in delayed rectifier potassium channels and potentially other voltage-gated channels.

  11. Diverse levels of an inwardly rectifying potassium conductance generate heterogeneous neuronal behavior in a population of dorsal cochlear nucleus pyramidal neurons.

    Science.gov (United States)

    Leao, Ricardo M; Li, Shuang; Doiron, Brent; Tzounopoulos, Thanos

    2012-06-01

    Homeostatic mechanisms maintain homogeneous neuronal behavior among neurons that exhibit substantial variability in the expression levels of their ionic conductances. In contrast, the mechanisms, which generate heterogeneous neuronal behavior across a neuronal population, remain poorly understood. We addressed this problem in the dorsal cochlear nucleus, where principal neurons exist in two qualitatively distinct states: spontaneously active or not spontaneously active. Our studies reveal that distinct activity states are generated by the differential levels of a Ba(2+)-sensitive, inwardly rectifying potassium conductance (K(ir)). Variability in K(ir) maximal conductance causes variations in the resting membrane potential (RMP). Low K(ir) conductance depolarizes RMP to voltages above the threshold for activating subthreshold-persistent sodium channels (Na(p)). Once Na(p) channels are activated, the RMP becomes unstable, and spontaneous firing is triggered. Our results provide a biophysical mechanism for generating neural heterogeneity, which may play a role in the encoding of sensory information.

  12. High-Precision Half-Wave Rectifier Circuit In Dual Phase Output Mode

    Directory of Open Access Journals (Sweden)

    Theerayut Jamjaem

    2009-12-01

    Full Text Available This paper present high-precision half-wave rectifier circuit in dual phase output mode by 0.5 μm CMOS technology, +/- 1.5 V low voltage, it has received input signal and sent output current signal, respond in high frequency. The main structure compound with CMOS inverter circuit, common source circuit, and current mirror circuit. Simulation and confirmation quality of working by PSpice program, then it able to operating at maximum frequency about 100 MHz, maximum input current range about 400 μAp-p, high precision output signal, low power dissipation, and uses a little transistor.Keywords-component; half-wave; rectifier circuit; highprecession; dual phase;

  13. An Integrated Circuit Design of High Efficiency Parallel-SSHI Rectifier for Piezoelectric Energy Harvesting

    Science.gov (United States)

    Hsieh, Y. C.; Chen, J. J.; Chen, H. S.; Wu, W. J.

    2016-11-01

    This paper presents the design and implementation of a rectifier for piezoelectric energy harvesting based on the parallel-synchronized-switch harvesting-on-inductor (P-SSHI) technique, also known as bias flip circuit[1]. The circuit is implemented with 0.25 μm CMOS high voltage process with only 0.9648 mm2 chip area. Post-layout simulation of the circuit shows the circuit extracts 336% more power compared with the full-bridge rectifier. The system's average control power loss is 26 μW while operating with a self-made MEMS piezoelectric transducer with output current 25 μA 120Hz and internal capacitance 6.45nF. The output power is 43.42 μW under optimal load of 1.5 MΩ.

  14. Characterization of inward-rectifier K+ channel inhibition by antiarrhythmic piperazine.

    Science.gov (United States)

    Xu, Yanping; Lu, Zhe

    2004-12-14

    Strong inward-rectifier K(+) (Kir) channels play a significant role in shaping the cardiac action potential: they help produce its long plateau and accelerate its rate of repolarization. Consequently, genetic deletion of the gene encoding the strongly rectifying K(+) channel IRK1 (Kir2.1) prolongs the cardiac action potential in mice. In principle, broadening the action potential lengthens the refractory period, which may in turn be antiarrhythmogenic. Interestingly, previous studies showed that piperazine, an inexpensive and safe anthelmintic, both inhibits IRK1 channels and is antiarrhythmic in some animal preparations. This potential pharmacological benefit motivated us to further characterize the energetic, kinetic, and molecular properties of IRK1 inhibition by piperazine. We show how its blocking characteristics, in particular, its shallow voltage dependence, allow piperazine to be effective even in the presence of high-affinity polyamine blockers. We also examine the channel selectivity of piperazine and its molecular determinants.

  15. High Efficiency Three-phase Power Factor Correction Rectifier using Wide Band-Gap Devices

    DEFF Research Database (Denmark)

    Kouchaki, Alireza

    2016-01-01

    Improving the conversion efficiency of power factor correction (PFC) rectifiers has become compelling due to their wide applications such as adjustable speed drives, uninterruptible power supplies (UPS), and battery chargers for electric vehicles (EVs). The attention to PFCs has increased even more...... power devices. Therefore, the PFC switching frequency using WBG devices can potentially be increased. This advantage helps the reactive components to be reduced in size. However, it also brings challenges such as identifying a proper material for inductive components that has lower loss and layout....... Therefore, current controllers are also important to be investigated in this project. In this PhD research work, a comprehensive design of a two-level three-phase PFC rectifier using silicon-carbide (SiC) switches to achieve high efficiency is presented. The work is divided into two main parts: 1) Optimum...

  16. Rectifying barrier at GaN/SiC hetero-junction studied with positron annihilation spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Hu Yi-Fan; Beling C D

    2005-01-01

    Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This "rectifying" effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit (VEPF) analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.

  17. Hydrogen Sulfide Regulates Inward-Rectifying K+ Channels in Conjunction with Stomatal Closure1[OPEN

    Science.gov (United States)

    Papanatsiou, Maria; Scuffi, Denisse; Blatt, Michael R.; García-Mata, Carlos

    2015-01-01

    Hydrogen sulfide (H2S) is the third biological gasotransmitter, and in animals, it affects many physiological processes by modulating ion channels. H2S has been reported to protect plants from oxidative stress in diverse physiological responses. H2S closes stomata, but the underlying mechanism remains elusive. Here, we report the selective inactivation of current carried by inward-rectifying K+ channels of tobacco (Nicotiana tabacum) guard cells and show its close parallel with stomatal closure evoked by submicromolar concentrations of H2S. Experiments to scavenge H2S suggested an effect that is separable from that of abscisic acid, which is associated with water stress. Thus, H2S seems to define a unique and unresolved signaling pathway that selectively targets inward-rectifying K+ channels. PMID:25770153

  18. High Efficiency Three-phase Power Factor Correction Rectifier using Wide Band-Gap Devices

    OpenAIRE

    2016-01-01

    Improving the conversion efficiency of power factor correction (PFC) rectifiers has become compelling due to their wide applications such as adjustable speed drives, uninterruptible power supplies (UPS), and battery chargers for electric vehicles (EVs). The attention to PFCs has increased even more since grid regulations have become stricter in terms of injected harmonic and power quality. Therefore, improving the efficiency and the power quality of PFCs are the main objectives of this PhD wo...

  19. Modeling and control of three phase rectifier with electronic smoothing inductor

    DEFF Research Database (Denmark)

    Singh, Yash Veer; Rasmussen, Peter Omand; Andersen, Torben Ole

    2011-01-01

    controlled variable impedance. This increases power factor (PF) and reduces total harmonic distortions (THDs) in mains current. The ESI based rectifier enables compact and cost effective design of three phase electric drive as size of passive components is reduced significantly. In order to carry out...... stability and voltage regulation studies, the average, small-signal, dynamic model and control strategy of the ESI is developed and validated by simulation and laboratory measurements....

  20. 2011 NOAA Ortho-rectified Mosaic of Texas: Integrated Ocean and Coastal Mapping Product (NODC Accession 0105604)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2012 NOAA Near Infrared MLLW Ortho-rectified Mosaic of Sewee Bay to Santee River, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2012 NOAA Ortho-rectified MHW Near-Infrared Mosaic of Washington: Seattle and Lake Washington Ship Canal

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2013 NOAA Ortho-rectified Mean High Water Near-Infrared Mosaic of Calcasieu Lake and Lake Charles, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2011 NOAA Ortho-rectified Near-infrared Mosaic of Sewee Bay to Santee River, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2016 NOAA NGS Ortho-rectified Mean High Water Near-Infrared Mosaic of St. Johns River, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2013 NOAA Ortho-rectified Near-Infrared Mosaic of Virginia: Norfolk, Hampton Roads,and Newport News

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2012 NOAA Ortho-rectified Color Mosaic of Tacoma and Gig Harbor, Washington: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2011 NOAA Ortho-rectified Near Infrared Mosaic of Hampton Harbor to Frost Point, New Hampshire (Mean High Water)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2012 NOAA Ortho-rectified Color MLLW Mosaic of Alabama: Bon Secour Bay and Weeks Bay NERR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2011 NOAA Ortho-rectified Mosaic of Hampton Harbor to Frost Point, New Hampshire (Mean High Water)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2015 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Jacksonville Beach to Mosquito Lagoon, Florida

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Lopez Rock to Pescadero Point, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2013 NOAA Ortho-rectified Mean High Water Color Mosaic of North Carolina: Wilmington - Caswell Beach to Wrightsville Beach

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2011 NOAA Ortho-rectified Mosaic of Hampton Harbor to Frost Point, New Hampshire (Mean Lower Low Water)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2009 NOAA Ortho-rectified Near Infrared Mosaic of Georgia: Kings Bay and Fernandina Beach (NODC Accession 0092435)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2012 NOAA Ortho-rectified Color Mosaic of Christiansted Harbor, St. Croix, U.S. Virgin Islands

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. 2012 NOAA Ortho-rectified Near-infrared MLLW Mosaic of Bodega Bay to Shelter Cove, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  18. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Alabama: Bon Secour Bay and Weeks Bay NERR

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2011 NOAA Ortho-rectified Near-infrared Mosaic of Murphy Island to Winyah Bay, South Carolina

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2015 NOAA Ortho-rectified Color Mosaic of Port Everglades, Florida: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  1. 2011 NOAA Ortho-rectified Mosaic of Anguilla Harbor, St. Croix, U.S. Virgin Islands (NODC Accession 0086076)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  2. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Seal Rock to Lopez Rock, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  3. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of Corpus Christi and Port Ingleside, Texas

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  4. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Pescadero Point to Bodega Bay, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  5. 2012 NOAA Ortho-rectified Mosaic of Laguna Madre / Arroyo Colorado, Texas: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  6. 2012 NOAA Ortho-rectified Near-Infrared Mosaic of Oregon: Columbia River - Bonneville Dam to Lake Umatilla

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  7. 2015 NOAA NGS Ortho-rectified Mean Low Low Water Color Mosaic of Augusta to Newcastle, Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  8. 2015 NOAA NGS Ortho-rectified Mean High Water Near-Infrared Mosaic of Augusta to Newcastle, Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  9. 2015 NOAA Ortho-rectified Color Mosaic of Wilmington and Newcastle, Delaware: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  10. 2015 NOAA NGS Ortho-rectified Mean Low Low Water Near-Infrared Mosaic of Augusta to Newcastle, Maine

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  11. 2012 NOAA Ortho-rectified Near-Infrared MLLW Mosaic of Shelter Cove to Cone Rock, California

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  12. 2016 NOAA NGS Ortho-rectified Near-Infrared Mosaic of New Orleans and South Louisiana, Louisiana

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  13. 2015 NOAA Ortho-rectified Color Mosaic of Redwood City, California: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  14. 2010 NOAA Near Infrared Ortho-rectified Mosaic of Louisiana: Mississippi River - Baton Rouge to Southwest Pass

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  15. 2014 NOAA Ortho-rectified Color Mosaic of The Everglades, Florida: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  16. 2013 NOAA Ortho-rectified Mean High Water Infrared Mosaic of North Carolina: Wilmington - Caswell Beach to Wrightsville Beach

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  17. Aerial Photography and Imagery, Oblique, Pictometry done Spring 2009, not rectified into GIS yet, Published in 2009, Jones County GIS.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Aerial Photography and Imagery, Oblique dataset as of 2009. It is described as 'Pictometry done Spring 2009, not rectified into GIS yet'. Data by this publisher...

  18. 2010 NOAA Ortho-rectified Color MHW Mosaic of South Carolina: Hilton Head to St. Helena Sound

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  19. 2014 NOAA Ortho-rectified Near-Infrared Mosaic of The Everglades, Florida: Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

  20. 2012 NOAA Ortho-rectified Mosaic of Texas: Seadrift to Palacios Integrated Ocean and Coastal Mapping Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...