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Sample records for kainate receptors kars

  1. Lessons from crystal structures of kainate receptors

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    Møllerud, Stine; Frydenvang, Karla Andrea; Pickering, Darryl S

    2017-01-01

    Kainate receptors belong to the family of ionotropic glutamate receptors. These receptors assemble from five subunits (GluK1-5) into tetrameric ion channels. Kainate receptors are located at both pre- and postsynaptic membranes in the central nervous system where they contribute to excitatory...... synaptic transmission and modulate network excitability by regulating neurotransmitter release. Dysfunction of kainate receptors has been implicated in several neurological disorders such as epilepsy, schizophrenia and depression. Here we provide a review on the current understanding of kainate receptor...

  2. Functional Validation of Heteromeric Kainate Receptor Models.

    Science.gov (United States)

    Paramo, Teresa; Brown, Patricia M G E; Musgaard, Maria; Bowie, Derek; Biggin, Philip C

    2017-11-21

    Kainate receptors require the presence of external ions for gating. Most work thus far has been performed on homomeric GluK2 but, in vivo, kainate receptors are likely heterotetramers. Agonists bind to the ligand-binding domain (LBD) which is arranged as a dimer of dimers as exemplified in homomeric structures, but no high-resolution structure currently exists of heteromeric kainate receptors. In a full-length heterotetramer, the LBDs could potentially be arranged either as a GluK2 homomer alongside a GluK5 homomer or as two GluK2/K5 heterodimers. We have constructed models of the LBD dimers based on the GluK2 LBD crystal structures and investigated their stability with molecular dynamics simulations. We have then used the models to make predictions about the functional behavior of the full-length GluK2/K5 receptor, which we confirmed via electrophysiological recordings. A key prediction and observation is that lithium ions bind to the dimer interface of GluK2/K5 heteromers and slow their desensitization. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  3. Cerebellar Kainate Receptor-Mediated Facilitation of Glutamate Release Requires Ca2+-Calmodulin and PKA

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    Rafael Falcón-Moya

    2018-06-01

    Full Text Available We elucidated the mechanisms underlying the kainate receptor (KAR-mediated facilitatory modulation of synaptic transmission in the cerebellum. In cerebellar slices, KA (3 μM increased the amplitude of evoked excitatory postsynaptic currents (eEPSCs at synapses between axon terminals of parallel fibers (PF and Purkinje neurons. KA-mediated facilitation was antagonized by NBQX under condition where AMPA receptors were previously antagonized. Inhibition of protein kinase A (PKA suppressed the effect of KA on glutamate release, which was also obviated by the prior stimulation of adenylyl cyclase (AC. KAR-mediated facilitation of synaptic transmission was prevented by blocking Ca2+ permeant KARs using philanthotoxin. Furthermore, depletion of intracellular Ca2+ stores by thapsigargin, or inhibition of Ca2+-induced Ca2+-release by ryanodine, abrogated the synaptic facilitation by KA. Thus, the KA-mediated modulation was conditional on extracellular Ca2+ entry through Ca2+-permeable KARs, as well as and mobilization of Ca2+ from intracellular stores. Finally, KAR-mediated facilitation was sensitive to calmodulin inhibitors, W-7 and calmidazolium, indicating that the increased cytosolic [Ca2+] sustaining KAR-mediated facilitation of synaptic transmission operates through a downstream Ca2+/calmodulin coupling. We conclude that, at cerebellar parallel fiber-Purkinje cell synapses, presynaptic KARs mediate glutamate release facilitation, and thereby enhance synaptic transmission through Ca2+-calmodulin dependent activation of adenylyl cyclase/cAMP/protein kinase A signaling.

  4. Neto2 Assembles with Kainate Receptors in DRG Neurons during Development and Modulates Neurite Outgrowth in Adult Sensory Neurons.

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    Vernon, Claire G; Swanson, Geoffrey T

    2017-03-22

    Peripheral sensory neurons in the dorsal root ganglia (DRG) are the initial transducers of sensory stimuli, including painful stimuli, from the periphery to central sensory and pain-processing centers. Small- to medium-diameter non-peptidergic neurons in the neonatal DRG express functional kainate receptors (KARs), one of three subfamilies of ionotropic glutamate receptors, as well as the putative KAR auxiliary subunit Neuropilin- and tolloid-like 2 (Neto2). Neto2 alters recombinant KAR function markedly but has yet to be confirmed as an auxiliary subunit that assembles with and alters the function of endogenous KARs. KARs in neonatal DRG require the GluK1 subunit as a necessary constituent, but it is unclear to what extent other KAR subunits contribute to the function and proposed roles of KARs in sensory ganglia, which include promotion of neurite outgrowth and modulation of glutamate release at the DRG-dorsal horn synapse. In addition, KARs containing the GluK1 subunit are implicated in modes of persistent but not acute pain signaling. We show here that the Neto2 protein is highly expressed in neonatal DRG and modifies KAR gating in DRG neurons in a developmentally regulated fashion in mice. Although normally at very low levels in adult DRG neurons, Neto2 protein expression can be upregulated via MEK/ERK signaling and after sciatic nerve crush and Neto2 -/- neurons from adult mice have stunted neurite outgrowth. These data confirm that Neto2 is a bona fide KAR auxiliary subunit that is an important constituent of KARs early in sensory neuron development and suggest that Neto2 assembly is critical to KAR modulation of DRG neuron process outgrowth. SIGNIFICANCE STATEMENT Pain-transducing peripheral sensory neurons of the dorsal root ganglia (DRG) express kainate receptors (KARs), a subfamily of glutamate receptors that modulate neurite outgrowth and regulate glutamate release at the DRG-dorsal horn synapse. The putative KAR auxiliary subunit Neuropilin- and

  5. Distinct Subunit Domains Govern Synaptic Stability and Specificity of the Kainate Receptor

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    Christoph Straub

    2016-07-01

    Full Text Available Synaptic communication between neurons requires the precise localization of neurotransmitter receptors to the correct synapse type. Kainate-type glutamate receptors restrict synaptic localization that is determined by the afferent presynaptic connection. The mechanisms that govern this input-specific synaptic localization remain unclear. Here, we examine how subunit composition and specific subunit domains contribute to synaptic localization of kainate receptors. The cytoplasmic domain of the GluK2 low-affinity subunit stabilizes kainate receptors at synapses. In contrast, the extracellular domain of the GluK4/5 high-affinity subunit synergistically controls the synaptic specificity of kainate receptors through interaction with C1q-like proteins. Thus, the input-specific synaptic localization of the native kainate receptor complex involves two mechanisms that underlie specificity and stabilization of the receptor at synapses.

  6. Medicinal Chemistry of Competitive Kainate Receptor Antagonists

    Science.gov (United States)

    2010-01-01

    Kainic acid (KA) receptors belong to the group of ionotropic glutamate receptors and are expressed throughout in the central nervous system (CNS). The KA receptors have been shown to be involved in neurophysiological functions such as mossy fiber long-term potentiation (LTP) and synaptic plasticity and are thus potential therapeutic targets in CNS diseases such as schizophrenia, major depression, neuropathic pain and epilepsy. Extensive effort has been made to develop subtype-selective KA receptor antagonists in order to elucidate the physiological function of each of the five subunits known (GluK1−5). However, to date only selective antagonists for the GluK1 subunit have been discovered, which underlines the strong need for continued research in this area. The present review describes the structure−activity relationship and pharmacological profile for 10 chemically distinct classes of KA receptor antagonists comprising, in all, 45 compounds. To the medicinal chemist this information will serve as reference guidance as well as an inspiration for future effort in this field. PMID:22778857

  7. Structure and assembly mechanism for heteromeric kainate receptors.

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    Kumar, Janesh; Schuck, Peter; Mayer, Mark L

    2011-07-28

    Native glutamate receptor ion channels are tetrameric assemblies containing two or more different subunits. NMDA receptors are obligate heteromers formed by coassembly of two or three divergent gene families. While some AMPA and kainate receptors can form functional homomeric ion channels, the KA1 and KA2 subunits are obligate heteromers which function only in combination with GluR5-7. The mechanisms controlling glutamate receptor assembly involve an initial step in which the amino terminal domains (ATD) assemble as dimers. Here, we establish by sedimentation velocity that the ATDs of GluR6 and KA2 coassemble as a heterodimer of K(d) 11 nM, 32,000-fold lower than the K(d) for homodimer formation by KA2; we solve crystal structures for the GluR6/KA2 ATD heterodimer and heterotetramer assemblies. Using these structures as a guide, we perform a mutant cycle analysis to probe the energetics of assembly and show that high-affinity ATD interactions are required for biosynthesis of functional heteromeric receptors. Copyright © 2011 Elsevier Inc. All rights reserved.

  8. Role of desensitization and subunit expression for kainate receptor-mediated neurotoxicity in murine neocortical cultures

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1999-01-01

    ) toxicity mediated by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) receptors, and (3) toxicity that can be mediated by kainate receptors when desensitization of the receptors is blocked. The indirect action at NMDA receptors was discovered because (5R, 10S)-(+)-5-methyl-10,11-dihydro-5H...... nedioxy-5H-2,3-benzodiazepine (GYKI 53655), a selective AMPA receptor antagonist, abolished the remaining toxicity. These results indicated that kainate- and domoate-mediated toxicity involves both the NMDA and the AMPA receptors. Pretreatment of the cultures with concanavalin A to prevent desensitization...

  9. Preferential assembly of heteromeric kainate and AMPA receptor amino terminal domains.

    Science.gov (United States)

    Zhao, Huaying; Lomash, Suvendu; Chittori, Sagar; Glasser, Carla; Mayer, Mark L; Schuck, Peter

    2017-10-23

    Ion conductivity and the gating characteristics of tetrameric glutamate receptor ion channels are determined by their subunit composition. Competitive homo- and hetero-dimerization of their amino-terminal domains (ATDs) is a key step controlling assembly. Here we measured systematically the thermodynamic stabilities of homodimers and heterodimers of kainate and AMPA receptors using fluorescence-detected sedimentation velocity analytical ultracentrifugation. Measured affinities span many orders of magnitude, and complexes show large differences in kinetic stabilities. The association of kainate receptor ATD dimers is generally weaker than the association of AMPA receptor ATD dimers, but both show a general pattern of increased heterodimer stability as compared to the homodimers of their constituents, matching well physiologically observed receptor combinations. The free energy maps of AMPA and kainate receptor ATD dimers provide a framework for the interpretation of observed receptor subtype combinations and possible assembly pathways.

  10. Differences in kainate receptor involvement in hippocampal mossy fibre long-term potentiation depending on slice orientation.

    Science.gov (United States)

    Sherwood, John L; Amici, Mascia; Dargan, Sheila L; Culley, Georgia R; Fitzjohn, Stephen M; Jane, David E; Collingridge, Graham L; Lodge, David; Bortolotto, Zuner A

    2012-09-01

    Long-term potentiation (LTP) is a well-established experimental model used to investigate the synaptic basis of learning and memory. LTP at mossy fibre - CA3 synapses in the hippocampus is unusual because it is normally N-methyl-d-aspartate (NMDA) receptor-independent. Instead it seems that the trigger for mossy fibre LTP involves kainate receptors (KARs). Although it is generally accepted that pre-synaptic KARs play an essential role in frequency facilitation and LTP, their subunit composition remains a matter of significant controversy. We have reported previously that both frequency facilitation and LTP can be blocked by selective antagonism of GluK1 (formerly GluR5/Glu(K5))-containing KARs, but other groups have failed to reproduce this effect. Moreover, data from receptor knockout and mRNA expression studies argue against a major role of GluK1, supporting a more central role for GluK2 (formerly GluR6/Glu(K6)). A potential reason underlying the controversy in the pharmacological experiments may reside in differences in the preparations used. Here we show differences in pharmacological sensitivity of synaptic plasticity at mossy fibre - CA3 synapses depend critically on slice orientation. In transverse slices, LTP of fEPSPs was invariably resistant to GluK1-selective antagonists whereas in parasagittal slices LTP was consistently blocked by GluK1-selective antagonists. In addition, there were pronounced differences in the magnitude of frequency facilitation and the sensitivity to the mGlu2/3 receptor agonist DCG-IV. Using anterograde labelling of granule cells we show that slices of both orientations possess intact mossy fibres and both large and small presynaptic boutons. Transverse slices have denser fibre tracts but a smaller proportion of giant mossy fibre boutons. These results further demonstrate a considerable heterogeneity in the functional properties of the mossy fibre projection. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. The prostaglandin EP1 receptor potentiates kainate receptor activation via a protein kinase C pathway and exacerbates status epilepticus

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    Rojas, Asheebo; Gueorguieva, Paoula; Lelutiu, Nadia; Quan, Yi; Shaw, Renee; Dingledine, Raymond

    2014-01-01

    Prostaglandin E2 (PGE2) regulates membrane excitability, synaptic transmission, plasticity, and neuronal survival. The consequences of PGE2 release following seizures has been the subject of much study. Here we demonstrate that the prostaglandin E2 receptor 1 (EP1, or Ptger1) modulates native kainate receptors, a family of ionotropic glutamate receptors widely expressed throughout the central nervous system. Global ablation of the EP1 gene in mice (EP1-KO) had no effect on seizure threshold after kainate injection but reduced the likelihood to enter status epilepticus. EP1-KO mice that did experience typical status epilepticus had reduced hippocampal neurodegeneration and a blunted inflammatory response. Further studies with native prostanoid and kainate receptors in cultured cortical neurons, as well as with recombinant prostanoid and kainate receptors expressed in Xenopus oocytes, demonstrated that EP1 receptor activation potentiates heteromeric but not homomeric kainate receptors via a second messenger cascade involving phospholipase C, calcium and protein kinase C. Three critical GluK5 C-terminal serines underlie the potentiation of the GluK2/GluK5 receptor by EP1 activation. Taken together, these results indicate that EP1 receptor activation during seizures, through a protein kinase C pathway, increases the probability of kainic acid induced status epilepticus, and independently promotes hippocampal neurodegeneration and a broad inflammatory response. PMID:24952362

  12. Genetic ablation of the GluK4 kainate receptor subunit causes anxiolytic and antidepressant-like behavior in mice.

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    Catches, Justin S; Xu, Jian; Contractor, Anis

    2012-03-17

    There is a clear link between dysregulation of glutamatergic signaling and mood disorders. Genetic variants in the glutamate receptor gene GRIK4, which encodes the kainate receptor subunit GluK4, alter the susceptibility for depression, bipolar disorder and schizophrenia. Here we demonstrate that Grik4(-/-) mice have reduced anxiety and an antidepressant-like phenotype. In the elevated zero-maze, a test for anxiety and risk taking behavior, Grik4(-/-) mice spent significantly more time exploring the open areas of the maze. In anxiogenic tests of marble-burying and novelty-induced suppression of feeding, anxiety-like behavior was consistently reduced in knockout animals. In the forced swim test, a test of learned helplessness that is used to determine depression-like behavior, knockout mice demonstrated significantly less immobility suggesting that Grik4 ablation has an antidepressant-like effect. Finally, in the sucrose preference test, a test for anhedonia in rodents, Grik4(-/-) mice demonstrated increased sucrose preference. Expression of the GluK4 receptor subunit in the forebrain is restricted to the CA3 region of the hippocampus and dentate gyrus regions where KARs are known to modulate synaptic plasticity. We tested whether Grik4 ablation had effects on mossy fiber (MF) plasticity and found there to be a significant impairment in LTP likely through a loss of KAR modulation of excitability of the presynaptic MF axons. These studies demonstrate a clear anxiolytic and antidepressant phenotype associated with ablation of Grik4 and a parallel disruption in hippocampal plasticity, providing support for the importance of this receptor subunit in mood disorders. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Effects of Chronic Alcohol Exposure on Kainate Receptor-Mediated Neurotransmission in the Hippocampus

    Science.gov (United States)

    2004-09-01

    12917-12922, 1999. Frerking M, and Nicoll RA. Synaptic kainate receptors. Cur Opin Neurobio 10:342-351, 2000. Harvey J and Lacey MG. A postsynaptic...electrophysiological research. Ironically, this preparation was originally developed for use in biochemical studies characterizing energy metabolism in neuronal

  14. NMDA and kainate receptor expression, long-term potentiation, and neurogenesis in the hippocampus of long-lived Ames dwarf mice.

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    Sharma, Sunita; Darland, Diane; Lei, Saobo; Rakoczy, Sharlene; Brown-Borg, Holly M

    2012-06-01

    In the current study, we investigated changes in N-methyl D-aspartate (NMDA) and kainate receptor expression, long-term potentiation (LTP), and neurogenesis in response to neurotoxic stress in long-living Ames dwarf mice. We hypothesized that Ames dwarf mice have enhanced neurogenesis that enables retention of spatial learning and memory with age and promotes neurogenesis in response to injury. Levels of the NMDA receptors (NR)1, NR2A, NR2B, and the kainate receptor (KAR)2 were increased in Ames dwarf mice, relative to wild-type littermates. Quantitative assessment of the excitatory postsynaptic potential in Schaffer collaterals in hippocampal slices from Ames dwarf mice showed an increased response in high-frequency induced LTP over time compared with wild type. Kainic acid (KA) injection was used to promote neurotoxic stress-induced neurogenesis. KA mildly increased the number of doublecortin-positive neurons in wild-type mice, but the response was significantly enhanced in the Ames dwarf mice. Collectively, these data support our hypothesis that the enhanced learning and memory associated with the Ames dwarf mouse may be due to elevated levels of NMDA and KA receptors in hippocampus and their ability to continue producing new neurons in response to neuronal damage.

  15. Neto2 influences on kainate receptor pharmacology and function

    DEFF Research Database (Denmark)

    Han, Liwei; Howe, James; Pickering, Darryl S

    2016-01-01

    the mechanism of Neto2 modulation is still unclear, gain-of-function results from the characterization of GluK1-GluA2 chimeras indicate that the GluK1 sequences included in these chimeras (part or all of the TMD and part of the linkers between the TMDs and LBD) play a key role in Neto2 modulation of KAR...

  16. N1-Substituted 2,3-Quinoxalinediones as Kainate Receptor Antagonists: X-ray Crystallography, Structure-Affinity Relationships and in vitro Pharmacology

    DEFF Research Database (Denmark)

    Pallesen, Jakob Staun; Møllerud, Stine; Frydenvang, Karla Andrea

    2018-01-01

    Among the ionotropic glutamate receptors, the physiological role of kainate receptors is less well understood than AMPA and NMDA receptors, partly due to a lack of selective pharmacological tool compounds. Although ligands with selectivity towards the kainate receptor subtype GluK1 are available,...

  17. Design, synthesis and structure-activity relationships of novel phenylalanine-based amino acids as kainate receptors ligands

    DEFF Research Database (Denmark)

    Szymańska, Ewa; Chałupnik, Paulina; Szczepańska, Katarzyna

    2016-01-01

    A new series of carboxyaryl-substituted phenylalanines was designed, synthesized and pharmacologically characterized in vitro at native rat ionotropic glutamate receptors as well as at cloned homomeric kainate receptors GluK1-GluK3. Among them, six compounds bound to GluK1 receptor subtypes with ...

  18. Type II and III Taste Bud Cells Preferentially Expressed Kainate Glutamate Receptors in Rats.

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    Lee, Sang-Bok; Lee, Cil-Han; Kim, Se-Nyun; Chung, Ki-Myung; Cho, Young-Kyung; Kim, Kyung-Nyun

    2009-12-01

    Glutamate-induced cobalt uptake reveals that non-NMDA glutamate receptors (GluRs) are present in rat taste bud cells. Previous studies involving glutamate induced cobalt staining suggest this uptake mainly occurs via kainate type GluRs. It is not known which of the 4 types of taste bud cells express subunits of kainate GluR. Circumvallate and foliate papillae of Sprague-Dawley rats (45~60 days old) were used to search for the mRNAs of subunits of non-NMDA GluRs using RT-PCR with specific primers for GluR1-7, KA1 and KA2. We also performed RT-PCR for GluR5, KA1, PLCbeta2, and NCAM/SNAP 25 in isolated single cells from taste buds. Taste epithelium, including circumvallate or foliate papilla, express mRNAs of GluR5 and KA1. However, non-taste tongue epithelium expresses no subunits of non-NMDA GluRs. Isolated single cell RT-PCR reveals that the mRNAs of GluR5 and KA1 are preferentially expressed in Type II and Type III cells over Type I cells.

  19. Effects of pilocarpine and kainate-induced seizures on N-methyl-d-aspartate receptor gene expression in the rat hippocampus

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    Przewlocka, B.; Labuz, D.; Machelska, H.; Przewlocki, R.; Turchan, J.; Lason, W. [Department of Molecular Neuropharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow (Poland)

    1997-04-14

    The effects of pilocarpine- and kainate-induced seizures on N-methyl-d-aspartate receptor subunit-1 messenger RNA and [{sup 3}H]dizocilpine maleate binding were studied in the rat hippocampal formation. Pilocarpine- but not kainate-induced seizures decreased N-methyl-d-aspartate receptor subunit-1 messenger RNA level in dentate gyrus at 24 and 72 h after drug injection. Both convulsants decreased the messenger RNA level in CA1 pyramidal cells at 24 and 72 h, the effects of kainate being more profound. Kainate also decreased the N-methyl-d-aspartate receptor subunit-1 messenger RNA level in CA3 region after 24 and 72 h, whereas pilocarpine decreased the messenger RNA level at 72 h only. At 3 h after kainate, but not pilocarpine, an increased binding of [{sup 3}H]dizocilpine maleate in several apical dendritic fields of pyramidal cells was found. Pilocarpine reduced the [{sup 3}H]dizocilpine maleate binding in stratum lucidum only at 3 and 24 h after the drug injection. Pilocarpine but not kainate induced prolonged decrease in N-methyl-d-aspartate receptor subunit-1 gene expression in dentate gyrus. However, at the latest time measured, kainate had the stronger effect in decreasing both messenger RNA N-methyl-d-aspartate receptor subunit-1 and [{sup 3}H]dizocilpine maleate binding in CA1 and CA3 hippocampal pyramidal cells. The latter changes corresponded, however, to neuronal loss and may reflect higher neurotoxic potency of kainate.These data point to some differences in hippocampal N-methyl-d-aspartate receptor regulation in pilocarpine and kainate models of limbic seizures. Moreover, our results suggest that the N-methyl-d-aspartate receptor subunit-1 messenger RNA level is more susceptible to limbic seizures than is [{sup 3}H]dizocilpine maleate binding in the rat hippocampal formation. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  20. Effects of pilocarpine and kainate-induced seizures on N-methyl-d-aspartate receptor gene expression in the rat hippocampus

    International Nuclear Information System (INIS)

    Przewlocka, B.; Labuz, D.; Machelska, H.; Przewlocki, R.; Turchan, J.; Lason, W.

    1997-01-01

    The effects of pilocarpine- and kainate-induced seizures on N-methyl-d-aspartate receptor subunit-1 messenger RNA and [ 3 H]dizocilpine maleate binding were studied in the rat hippocampal formation. Pilocarpine- but not kainate-induced seizures decreased N-methyl-d-aspartate receptor subunit-1 messenger RNA level in dentate gyrus at 24 and 72 h after drug injection. Both convulsants decreased the messenger RNA level in CA1 pyramidal cells at 24 and 72 h, the effects of kainate being more profound. Kainate also decreased the N-methyl-d-aspartate receptor subunit-1 messenger RNA level in CA3 region after 24 and 72 h, whereas pilocarpine decreased the messenger RNA level at 72 h only. At 3 h after kainate, but not pilocarpine, an increased binding of [ 3 H]dizocilpine maleate in several apical dendritic fields of pyramidal cells was found. Pilocarpine reduced the [ 3 H]dizocilpine maleate binding in stratum lucidum only at 3 and 24 h after the drug injection. Pilocarpine but not kainate induced prolonged decrease in N-methyl-d-aspartate receptor subunit-1 gene expression in dentate gyrus. However, at the latest time measured, kainate had the stronger effect in decreasing both messenger RNA N-methyl-d-aspartate receptor subunit-1 and [ 3 H]dizocilpine maleate binding in CA1 and CA3 hippocampal pyramidal cells. The latter changes corresponded, however, to neuronal loss and may reflect higher neurotoxic potency of kainate.These data point to some differences in hippocampal N-methyl-d-aspartate receptor regulation in pilocarpine and kainate models of limbic seizures. Moreover, our results suggest that the N-methyl-d-aspartate receptor subunit-1 messenger RNA level is more susceptible to limbic seizures than is [ 3 H]dizocilpine maleate binding in the rat hippocampal formation. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. Glutamate AMPA/kainate receptors, not GABA(A) receptors, mediate estradiol-induced sex differences in the hypothalamus.

    Science.gov (United States)

    Todd, Brigitte J; Schwarz, Jaclyn M; Mong, Jessica A; McCarthy, Margaret M

    2007-02-15

    Sex differences in brain morphology underlie physiological and behavioral differences between males and females. During the critical perinatal period for sexual differentiation in the rat, gonadal steroids act in a regionally specific manner to alter neuronal morphology. Using Golgi-Cox impregnation, we examined several parameters of neuronal morphology in postnatal day 2 (PN2) rats. We found that in the ventromedial nucleus of the hypothalamus (VMN) and in areas just dorsal and just lateral to the VMN that there was a sex difference in total dendritic spine number (males greater) that was abolished by treating female neonates with exogenous testosterone. Dendritic branching was similarly sexually differentiated and hormonally modulated in the VMN and dorsal to the VMN. We then used spinophilin, a protein that positively correlates with the amount of dendritic spines, to investigate the mechanisms underlying these sex differences. Estradiol, which mediates most aspects of masculinization and is the aromatized product of testosterone, increased spinophilin levels in female PN2 rats to that of males. Muscimol, an agonist at GABA(A) receptors, did not affect spinophilin protein levels in either male or female neonates. Kainic acid, an agonist at glutamatergic AMPA/kainate receptors, mimicked the effect of estradiol in females. Antagonizing AMPA/kainate receptors with NBQX prevented the estradiol-induced increase in spinophilin in females but did not affect spinophilin level in males. (c) 2007 Wiley Periodicals, Inc.

  2. The dextromethorphan analog dimemorfan attenuates kainate-induced seizures via σ1 receptor activation: comparison with the effects of dextromethorphan

    OpenAIRE

    Shin, Eun-Joo; Nah, Seung-Yeol; Kim, Won-Ki; Ko, Kwang Ho; Jhoo, Wang-Kee; Lim, Yong-Kwang; Cha, Joo Young; Chen, Chieh-Fu; Kim, Hyoung-Chun

    2005-01-01

    In a previous study, we demonstrated that a dextromethorphan analog, dimemorfan, has neuroprotective effects.Dextromethorphan and dimemorfan are high-affinity ligands at σ1 receptors. Dextromethorphan has moderate affinities for phencyclidine sites, while dimemorfan has very low affinities for such sites, suggesting that these sites are not essential for the anticonvulsant actions of dimemorfan.Kainate (KA) administration (10 mg kg−1, i.p.) produced robust convulsions lasting 4–6 h in rats. P...

  3. Phenobarbital but not diazepam reduces AMPA/Kainate receptor mediated currents and exerts opposite actions on initial seizures in the neonatal rat hippocampus

    Directory of Open Access Journals (Sweden)

    Romain eNardou

    2011-07-01

    Full Text Available Diazepam (DZP and phenobarbital (PB are extensively used as first and second line drugs to treat acute seizures in neonates and their actions are thought to be mediated by increasing the actions of GABAergic signals. Yet, their efficacy is variable with occasional failure or even aggravation of recurrent seizures questioning whether other mechanisms are not involved in their actions. We have now compared the effects of DZP and PB on ictal-like events (ILEs in an in vitro model of mirror focus (MF. Using the three-compartment chamber with the two immature hippocampi and their commissural fibers placed in 3 different compartments, kainate was applied to one hippocampus and PB or DZP to the contralateral one, either after one ILE or after many recurrent ILEs that produce an epileptogenic MF. We report that in contrast to PB, DZP aggravated propagating ILEs from the start and did not prevent the formation of MF. PB reduced and DZP increased the network driven Giant Depolarising Potentials suggesting that PB may exert additional actions that are not mediated by GABA signalling. In keeping with this, PB but not DZP reduced field potentials recorded in the presence of GABA and NMDA receptor antagonists. These effects are mediated by a direct action on AMPA/Kainate receptors since PB: i reduced AMPA/Kainate receptor mediated currents induced by focal applications of glutamate ; ii reduced the amplitude and the frequency of AMPA but not NMDA receptor mediated miniature EPSCs; iii augmented the number of AMPA receptor mediated EPSCs failures evoked by minimal stimulation. These effects persisted in MF. Therefore, PB exerts its anticonvulsive actions partly by reducing AMPA/Kainate receptors mediated EPSCs in addition to the pro-GABA effects. We suggest that PB may have advantage over DZP in the treatment of initial neonatal seizures since the additional reduction of glutamate receptors mediated signals may reduce the severity of neonatal seizures.

  4. Different structural requirements for functional ion pore transplantation suggest different gating mechanisms of NMDA and kainate receptors.

    Science.gov (United States)

    Villmann, Carmen; Hoffmann, Jutta; Werner, Markus; Kott, Sabine; Strutz-Seebohm, Nathalie; Nilsson, Tanja; Hollmann, Michael

    2008-10-01

    Although considerable progress has been made in characterizing the physiological function of the high-affinity kainate (KA) receptor subunits KA1 and KA2, no homomeric ion channel function has been shown. An ion channel transplantation approach was employed in this study to directly test if homomerically expressed KA1 and KA2 pore domains are capable of conducting currents. Transplantation of the ion pore of KA1 or KA2 into GluR6 generated perfectly functional ion channels that allowed characterization of those electrophysiological and pharmacological properties that are determined exclusively by the ion pore of KA1 or KA2. This demonstrates for the first time that KA1 and KA2 ion pore domains are intrinsically capable of conducting ions even in homomeric pore assemblies. NMDA receptors, similar to KA1- or KA2-containing receptors, function only as heteromeric complexes. They are composed of NR1 and NR2 subunits, which both are non-functional when expressed homomerically. In contrast to NR1, the homomeric NR2B ion pore failed to translate ligand binding into pore opening when transplanted into GluR6. Similarly, heteromeric coexpression of the ion channel domains of both NR1 and NR2 inserted into GluR6 failed to produce functional channels. Therefore, we conclude that the mechanism underlying the ion channel opening in the obligatorily heterotetrameric NMDA receptors differs significantly from that in the facultatively heterotetrameric alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate and KA receptors.

  5. AMPA/kainate glutamate receptors contribute to inflammation, degeneration and pain related behaviour in inflammatory stages of arthritis

    Science.gov (United States)

    Bonnet, Cleo S; Williams, Anwen S; Gilbert, Sophie J; Harvey, Ann K; Evans, Bronwen A; Mason, Deborah J

    2015-01-01

    Objectives Synovial fluid glutamate concentrations increase in arthritis. Activation of kainate (KA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptors (GluRs) increase interleukin-6 (IL-6) release and cause arthritic pain, respectively. We hypothesised that AMPA and KA GluRs are expressed in human arthritis, and that intra-articular NBQX (AMPA/KA GluR antagonist) prevents pain and pathology in antigen-induced arthritis (AIA). Methods GluR immunohistochemistry was related to synovial inflammation and degradation in osteoarthritis (OA) and rheumatoid arthritis (RA). A single intra-articular NBQX injection was given at induction, and knee swelling and gait of AIA and AIA+NBQX rats compared over 21 days, before imaging, RT-qPCR, histology and immunohistochemistry of joints. Effects of NBQX on human primary osteoblast (HOB) activity were determined. Results AMPAR2 and KA1 immunolocalised to remodelling bone, cartilage and synovial cells in human OA and RA, and rat AIA. All arthritic tissues showed degradation and synovial inflammation. NBQX reduced GluR abundance, knee swelling (parthritis. PMID:24130267

  6. The dextromethorphan analog dimemorfan attenuates kainate-induced seizures via σ1 receptor activation: comparison with the effects of dextromethorphan

    Science.gov (United States)

    Shin, Eun-Joo; Nah, Seung-Yeol; Kim, Won-Ki; Ko, Kwang Ho; Jhoo, Wang-Kee; Lim, Yong-Kwang; Cha, Joo Young; Chen, Chieh-Fu; Kim, Hyoung-Chun

    2005-01-01

    In a previous study, we demonstrated that a dextromethorphan analog, dimemorfan, has neuroprotective effects. Dextromethorphan and dimemorfan are high-affinity ligands at σ1 receptors. Dextromethorphan has moderate affinities for phencyclidine sites, while dimemorfan has very low affinities for such sites, suggesting that these sites are not essential for the anticonvulsant actions of dimemorfan. Kainate (KA) administration (10 mg kg−1, i.p.) produced robust convulsions lasting 4–6 h in rats. Pre-treatment with dimemorfan (12 or 24 mg kg−1) reduced seizures in a dose-dependent manner. Dimemorfan pre-treatment also attenuated the KA-induced increases in c-fos/c-jun expression, activator protein (AP)-1 DNA-binding activity, and loss of cells in the CA1 and CA3 fields of the hippocampus. These effects of dimemorfan were comparable to those of dextromethorphan. The anticonvulsant action of dextromethorphan or dimemorfan was significantly counteracted by a selective σ1 receptor antagonist BD 1047, suggesting that the anticonvulsant action of dextromethorphan or dimemorfan is, at least in part, related to σ1 receptor-activated modulation of AP-1 transcription factors. We asked whether dimemorfan produces the behavioral side effects seen with dextromethorphan or dextrorphan (a phencyclidine-like metabolite of dextromethorphan). Conditioned place preference and circling behaviors were significantly increased in mice treated with phencyclidine, dextrorphan or dextromethorphan, while mice treated with dimemorfan showed no behavioral side effects. Our results suggest that dimemorfan is equipotent to dextromethorphan in preventing KA-induced seizures, while it may lack behavioral effects, such as psychotomimetic reactions. PMID:15723099

  7. Structure and affinity of two bicyclic glutamate analogues at AMPA and kainate receptors

    DEFF Research Database (Denmark)

    Møllerud, Stine; Pinto, Andrea; Marconi, Laura

    2017-01-01

    Ionotropic glutamate receptors (iGluRs) are involved in most of the fast excitatory synaptic transmission in the central nervous system. These receptors are important for learning and memory formation, but are also involved in the development of diseases such as Alzheimer’s disease, epilepsy...

  8. Pharmacology and crystal structure of novel 2,3-quinoxalinediones at kainate receptors

    DEFF Research Database (Denmark)

    Møllerud, Stine; Pallesen, Jakob Staun; Pasini, Diletta

    2017-01-01

    , within the KA receptor family (GluK1-5) only compounds with selectivity towards GluK1 exist [1]. Thus, there is an unmet need for Tool compounds with selectivity towards the remaining KA receptor subunits. Here we report the pharmacology of a series of novel N1-substituted 2,3-quinoxalinediones, as well....... Functional electrophysiological (TEVC) experiments indeed showed these compounds to be antagonists at cloned, homomeric KA receptors. The structure and pharmacology will be valuable for design of new and more GluK3-selective quinoxalinedione analogues....

  9. NMDA and AMPA/kainate glutamatergic receptors in the prelimbic medial prefrontal cortex modulate the elaborated defensive behavior and innate fear-induced antinociception elicited by GABAA receptor blockade in the medial hypothalamus.

    Science.gov (United States)

    de Freitas, Renato Leonardo; Salgado-Rohner, Carlos José; Biagioni, Audrey Francisco; Medeiros, Priscila; Hallak, Jaime Eduardo Cecílio; Crippa, José Alexandre S; Coimbra, Norberto Cysne

    2014-06-01

    The aim of the present study was to investigate the involvement of N-methyl-d-aspartate (NMDA) and amino-3-hydroxy-5-methyl-isoxazole-4-proprionate (AMPA)/kainate receptors of the prelimbic (PL) division of the medial prefrontal cortex (MPFC) on the panic attack-like reactions evoked by γ-aminobutyric acid-A receptor blockade in the medial hypothalamus (MH). Rats were pretreated with NaCl 0.9%, LY235959 (NMDA receptor antagonist), and NBQX (AMPA/kainate receptor antagonist) in the PL at 3 different concentrations. Ten minutes later, the MH was treated with bicuculline, and the defensive responses were recorded for 10 min. The antagonism of NMDA receptors in the PL decreased the frequency and duration of all defensive behaviors evoked by the stimulation of the MH and reduced the innate fear-induced antinociception. However, the pretreatment of the PL cortex with NBQX was able to decrease only part of defensive responses and innate fear-induced antinociception. The present findings suggest that the NMDA-glutamatergic system of the PL is critically involved in panic-like responses and innate fear-induced antinociception and those AMPA/kainate receptors are also recruited during the elaboration of fear-induced antinociception and in panic attack-related response. The activation of the glutamatergic neurotransmission of PL division of the MPFC during the elaboration of oriented behavioral reactions elicited by the chemical stimulation of the MH recruits mainly NMDA receptors in comparison with AMPA/kainate receptors.

  10. Stereostructure-activity studies on agonists at the AMPA and kainate subtypes of ionotropic glutamate receptors

    DEFF Research Database (Denmark)

    Johansen, Tommy N; Greenwood, Jeremy R; Frydenvang, Karla Andrea

    2003-01-01

    (S)-Glutamic acid (Glu), the major excitatory neurotransmitter in the central nervous system, operates through ionotropic as well as metabotropic receptors and is considered to be involved in certain neurological disorders and degenerative brain diseases that are currently without any satisfactory...

  11. 1H-cyclopentapyrimidine-2,4(1H,3H)-dione-related ionotropic glutamate receptors ligands. Structure-activity relationships and identification of potent and selective iGluR5 modulators

    DEFF Research Database (Denmark)

    Butini, Stefania; Pickering, Darryl S; Morelli, Elena

    2008-01-01

    (S)-CPW399 ((S)-1) is a potent and excitotoxic AMPA receptor partial agonist. Modifying the cyclopentane ring of (S)-1, we developed two of the most potent and selective functional antagonists (5 and 7) for kainate receptor (KA-R) subunit iGluR5. Derivatives 5 and 7, with their unique pharmacolog...

  12. Selective kainate receptor (GluK1) ligands structurally based upon1H-Cyclopentapyrimidin-2,4(1H,3H)-dione: synthesis, molecular modeling, and pharmacological and biostructural characterization

    DEFF Research Database (Denmark)

    Venskutonyte, Raminta; Butini, Stefania; Coccone, Salvatore Sanna

    2011-01-01

    The physiological function of kainate receptors (GluK1- GluK5) in the central nervous system is not fully understood yet. With the aim of developing potent and selective GluK1 ligands, we have synthesized a series of new thiophene-based GluK1 agonists (6a-c) and antagonists (7a-d). Pharmacologica...

  13. Evidence for a Specific Integrative Mechanism for Episodic Memory Mediated by AMPA/kainate Receptors in a Circuit Involving Medial Prefrontal Cortex and Hippocampal CA3 Region.

    Science.gov (United States)

    de Souza Silva, Maria A; Huston, Joseph P; Wang, An-Li; Petri, David; Chao, Owen Yuan-Hsin

    2016-07-01

    We asked whether episodic-like memory requires neural mechanisms independent of those that mediate its component memories for "what," "when," and "where," and if neuronal connectivity between the medial prefrontal cortex (mPFC) and the hippocampus (HPC) CA3 subregion is essential for episodic-like memory. Unilateral lesion of the mPFC was combined with unilateral lesion of the CA3 in the ipsi- or contralateral hemispheres in rats. Episodic-like memory was tested using a task, which assesses the integration of memories for "what, where, and when" concomitantly. Tests for novel object recognition (what), object place (where), and temporal order memory (when) were also applied. Bilateral disconnection of the mPFC-CA3 circuit by N-methyl-d-aspartate (NMDA) lesions disrupted episodic-like memory, but left the component memories for object, place, and temporal order, per se, intact. Furthermore, unilateral NMDA lesion of the CA3 plus injection of (6-cyano-7-nitroquinoxaline-2,3-dione) (CNQX) (AMPA/kainate receptor antagonist), but not AP-5 (NMDA receptor antagonist), into the contralateral mPFC also disrupted episodic-like memory, indicating the mPFC AMPA/kainate receptors as critical for this circuit. These results argue for a selective neural system that specifically subserves episodic memory, as it is not critically involved in the control of its component memories for object, place, and time. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  14. Selective increases of AMPA, NMDA and kainate receptor subunit mRNAs in the hippocampus and orbitofrontal cortex but not in prefrontal cortex of human alcoholics

    Directory of Open Access Journals (Sweden)

    Zhe eJin

    2014-01-01

    Full Text Available Glutamate is the main excitatory transmitter in the human brain. Drugs that affect the glutamatergic signaling will alter neuronal excitability. Ethanol inhibits glutamate receptors. We examined the expression level of glutamate receptor subunit mRNAs in human post-mortem samples from alcoholics and compared the results to brain samples from control subjects. RNA from hippocampal dentate gyrus (HP-DG, orbitofrontal cortex (OFC, and dorso-lateral prefrontal cortex (DL-PFC samples from 21 controls and 19 individuals with chronic alcohol dependence were included in the study. Total RNA was assayed using quantitative RT-PCR. Out of the 16 glutamate receptor subunits, mRNAs encoding two AMPA (2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-ylpropanoic acid receptor subunits GluA2 and GluA3; three kainate receptor subunits GluK2, GluK3 and GluK5 and five NMDA (N-methyl-D-aspartate receptor subunits GluN1, GluN2A, GluN2C, GluN2D and GluN3A were significantly increased in the HP-DG region in alcoholics. In the OFC, mRNA encoding the NMDA receptor subunit GluN3A was increased, whereas in the DL-PFC, no differences in mRNA levels were observed. Our laboratory has previously shown that the expression of genes encoding inhibitory GABA-A receptors is altered in the HP-DG and OFC of alcoholics (Jin et al., 2011. Whether the changes in one neurotransmitter system drives changes in the other or if they change independently is currently not known. The results demonstrate that excessive long-term alcohol consumption is associated with altered expression of genes encoding glutamate receptors in a brain region-specific manner. It is an intriguing possibility that genetic predisposition to alcoholism may contribute to these gene expression changes.

  15. Kainate receptors in the rat hippocampus: A distribution and time course of changes in response to unilateral lesions of the entorhinal cortex

    International Nuclear Information System (INIS)

    Ulas, J.; Monaghan, D.T.; Cotman, C.W.

    1990-01-01

    The response of kainate receptors to deafferentation and subsequent reinnervation following unilateral entorhinal cortex lesions was studied in the rat hippocampus using quantitative in vitro autoradiography. The binding levels of [3H]kainic acid (KA) and changes in the distribution of KA sites were investigated in the dentate gyrus molecular layer (ML) and in various terminal zones in the CA1 field at 1, 3, 7, 14, 21, 30, and 60 d postlesion. The data from both the ipsilateral and contralateral hippocampus were compared with those from unoperated controls. The first changes in KA receptor distribution were observed 21 d postlesion when the dense band of KA receptors occupying the inner one-third of the ML expanded into the denervated outer two-thirds of the ipsilateral ML. The spreading of the KA receptor field into previously unoccupied zones continued 30 and 60 d postlesion. At these time points, the zone enriched in [3H]KA binding sites became significantly (on average 50%) wider than in unoperated controls. No changes were observed in either the distribution or binding levels in other hippocampal areas or in the contralateral hippocampus at any studied time point. Saturation analysis of binding in the ipsilateral ML 60 d postlesion revealed changes in the maximum number of receptor sites (Bmax) without changes in KA receptor affinity (Kd). The data suggest that the elevation of the [3H]KA binding in the outer two-thirds of the ML reflects an increase in the number of both low and high affinity receptor binding sites. The pattern of KA receptor redistribution was similar to the well-characterized pattern of sprouting of commissural/associational systems from the inner one-third into the outer two-thirds of the ML after entorhinal lesions

  16. Synthesis and in vitro pharmacology at AMPA and kainate preferring glutamate receptors of 4-heteroarylmethylidene glutamate analogues

    DEFF Research Database (Denmark)

    Valgeirsson, Jon; Christensen, Jeppe K; Kristensen, Anders S

    2003-01-01

    affinity for the GluR2 subtype of AMPA receptors. As an attempt to develop new pharmacological tools for studies of GluR5 receptors, (S)-E-4-(2-thiazolylmethylene)glutamic acid (4a) was designed as a structural hybrid between 1 and 3. 4a was shown to be a potent GluR5 agonist and a high affinity ligand...

  17. Topiramate via NMDA, AMPA/kainate, GABAA and Alpha2 receptors and by modulation of CREB/BDNF and Akt/GSK3 signaling pathway exerts neuroprotective effects against methylphenidate-induced neurotoxicity in rats.

    Science.gov (United States)

    Motaghinejad, Majid; Motevalian, Manijeh; Fatima, Sulail; Beiranvand, Tabassom; Mozaffari, Shiva

    2017-11-01

    Chronic abuse of methylphenidate (MPH) often causes neuronal cell death. Topiramate (TPM) carries neuroprotective effects, but its exact mechanism of action remains unclear. In the present study, the role of various doses of TPM and its possible mechanisms, receptors and signaling pathways involved against MPH-induced hippocampal neurodegeneration were evaluated in vivo. Thus, domoic acid (DOM) was used as AMPA/kainate receptor agonist, bicuculline (BIC) as GABA A receptor antagonist, ketamine (KET) as NMDA receptor antagonist, yohimbine (YOH) as α 2 adrenergic receptor antagonist and haloperidol (HAL) was used as dopamine D 2 receptor antagonist. Open field test (OFT) was used to investigate the disturbances in motor activity. Hippocampal neurodegenerative parameters were evaluated. Protein expressions of CREB/BDNF and Akt/GSK3 signaling pathways were also evaluated. Cresyl violet staining was performed to show and confirm the changes in the shape of the cells. TPM (70 and 100 mg/kg) reduced MPH-induced rise in lipid peroxidation, oxidized form of glutathione (GSSG), IL-1β and TNF-α levels, Bax expression and motor activity disturbances. In addition, TPM treatment increased Bcl-2 expression, the level of reduced form of glutathione (GSH) and the levels and activities of superoxide dismutase, glutathione peroxidase and glutathione reductase enzymes. TPM also inhibited MPH-induced hippocampal degeneration. Pretreatment of animals with DOM, BIC, KET and YOH inhibited TPM-induced neuroprotection and increased oxidative stress, neuroinflammation, neuroapoptosis and neurodegeneration while reducing CREB, BDNF and Akt protein expressions. Also pretreatment with DOM, BIC, KET and YOH inhibited TPM-induced decreases in GSK3. It can be concluded that the mentioned receptors by modulation of CREB/BDNF and Akt/GSK3 pathways, are involved in neuroprotection of TPM against MPH-induced neurodegeneration.

  18. Neuropeptide Y-stimulated [(35) S]GTPγs functional binding is reduced in the hippocampus after kainate-induced seizures in mice

    DEFF Research Database (Denmark)

    Elbrønd-Bek, Heidi; Olling, Janne Damm; Gøtzsche, Casper René

    2014-01-01

    , in this study, we explored functional NPY receptor activity in the mouse hippocampus and neocortex after kainate-induced seizures using NPY-stimulated [(35) S]GTPγS binding. Moreover, we also studied levels of [(125) I]-peptide YY (PYY) binding and NPY, Y1, Y2, and Y5 receptor mRNA in these kainate-treated mice...

  19. USHA P KAR

    Indian Academy of Sciences (India)

    Volume 42 Issue 2 June 2017 pp 333-344 Review. Regulation of dynamin family proteins by post-translational modifications · USHA P KAR HIMANI ... Volume 43 Issue 1 March 2018 pp 139-148 Article. Tetrahymena dynamin-related protein 6 self-assembles independent of membrane association · USHA P KAR HIMANI ...

  20. Morphology and kainate-receptor immunoreactivity of identified neurons within the entorhinal cortex projecting to superior temporal sulcus in the cynomolgus monkey

    Science.gov (United States)

    Good, P. F.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    Projections of the entorhinal cortex to the hippocampus are well known from the classical studies of Cajal (Ramon y Cajal, 1904) and Lorente de No (1933). Projections from the entorhinal cortex to neocortical areas are less well understood. Such connectivity is likely to underlie the consolidation of long-term declarative memory in neocortical sites. In the present study, a projection arising in layer V of the entorhinal cortex and terminating in a polymodal association area of the superior temporal gyrus has been identified with the use of retrograde tracing. The dendritic arbors of neurons giving rise to this projection were further investigated by cell filling and confocal microscopy with computer reconstruction. This analysis demonstrated that the dendritic arbor of identified projection neurons was largely confined to layer V, with the exception of a solitary, simple apical dendrite occasionally ascending to superficial laminae but often confined to the lamina dissecans (layer IV). Finally, immunoreactivity for glutamate-receptor subunit proteins GluR 5/6/7 of the dendritic arbor of identified entorhinal projection neurons was examined. The solitary apical dendrite of identified entorhinal projection neurons was prominently immunolabeled for GluR 5/6/7, as was the dendritic arbor of basilar dendrites of these neurons. The restriction of the large bulk of the dendritic arbor of identified entorhinal projection neurons to layer V implies that these neurons are likely to be heavily influenced by hippocampal output arriving in the deep layers of the entorhinal cortex. Immunoreactivity for GluR 5/6/7 throughout the dendritic arbor of such neurons indicates that this class of glutamate receptor is in a position to play a prominent role in mediating excitatory neurotransmission within hippocampal-entorhinal circuits.

  1. Eestlased Karli sillal

    Index Scriptorium Estoniae

    1999-01-01

    16. XI etendas kunstirühmitus "Nervous Cowboys" Tšehhi pealinna Praha Karli sillal Eesti taassünnipäevale pühendatud performance'i "Eesti kui märk". Mööduvaid prahalasi küsitlesid Kiwa ja Jasper Zoova. Praha Eesti saatkonnas avati näitus xerox-tehnikas graafilistest lehtedest ja performance'ite videodokumentatsioonidest

  2. Zinc movement in the brain under kainate-induced seizures.

    Science.gov (United States)

    Takeda, Atsushi; Hirate, Maki; Tamano, Haruna; Oku, Naoto

    2003-05-01

    On the basis of the evidence that elimination of 65Zn from the brain of epilepsy (EL) mice is facilitated by induction of seizures, zinc movement in the brain was studied in mice injected with kainate (12 mg/kg x 3), which exhibited status epilepticus within 120 min after the last injection of kainate. Zinc concentrations in the brain were determined 24 h after the last injection of kainate. Zinc concentrations in the hippocampus, amygdala and cerebral cortex, in which zinc-containing glutamatergic neuron terminals exist, were significantly decreased by the treatment with kainate, while that in the cerebellum was not decreased. Timm's stain in the brain was extensively attenuated 24 h after the last injection of kainate. These results indicate that zinc homeostasis in the brain is affected by kainate-induced seizures. In the hippocampus of rats injected with kainate (10 mg/kg), furthermore, the release of zinc and glutamate into the extracellular fluid was studied using in vivo microdialysis. The levels of zinc and glutamate in the perfusate were increased along with seizure severity after injection of kainate. It is likely that zinc concentration in the synaptic vesicles is decreased by the excess excitation of glutamatergic neurons. The present study suggests that the excessive release of zinc and glutamate from the neuron terminals under kainate-induced seizures is associated with the loss of zinc from the brain.

  3. Kainate-induced network activity in the anterior cingulate cortex.

    Science.gov (United States)

    Shinozaki, R; Hojo, Y; Mukai, H; Hashizume, M; Murakoshi, T

    2016-06-14

    Anterior cingulate cortex (ACC) plays a pivotal role in higher order processing of cognition, attention and emotion. The network oscillation is considered an essential means for integration of these CNS functions. The oscillation power and coherence among related areas are often dis-regulated in several psychiatric and pathological conditions with a hemispheric asymmetric manner. Here we describe the network-based activity of field potentials recorded from the superficial layer of the mouse ACC in vitro using submerged type recordings. A short activation by kainic acid administration to the preparation induced populational activities ranging over several frequency bands including theta (3-8Hz), alpha (8-12Hz), beta (13-30Hz), low gamma (30-50Hz) and high gamma (50-80Hz). These responses were repeatable and totally abolished by tetrodotoxin, and greatly diminished by inhibitors of ionotropic and metabotropic glutamate receptors, GABAA receptor or gap-junctions. These observations suggest that the kainate-induced network activity can be a useful model of the network oscillation in the ACC circuit. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  4. Kar5p is required for multiple functions in both inner and outer nuclear envelope fusion in Saccharomyces cerevisiae.

    Science.gov (United States)

    Rogers, Jason V; Rose, Mark D

    2014-12-02

    During mating in the budding yeast Saccharomyces cerevisiae, two haploid nuclei fuse via two sequential membrane fusion steps. SNAREs (i.e., soluble N-ethylmaleimide-sensitive factor attachment protein receptors) and Prm3p mediate outer nuclear membrane fusion, but the inner membrane fusogen remains unknown. Kar5p is a highly conserved transmembrane protein that localizes adjacent to the spindle pole body (SPB), mediates nuclear envelope fusion, and recruits Prm3p adjacent to the SPB. To separate Kar5p's functions, we tested localization, Prm3p recruitment, and nuclear fusion efficiency in various kar5 mutants. All domains and the conserved cysteine residues were essential for nuclear fusion. Several kar5 mutant proteins localized properly but did not mediate Prm3p recruitment; other kar5 mutant proteins localized and recruited Prm3p but were nevertheless defective for nuclear fusion, demonstrating additional functions beyond Prm3p recruitment. We identified one Kar5p domain required for SPB localization, which is dependent on the half-bridge protein Mps3p. Electron microscopy revealed a kar5 mutant that arrests with expanded nuclear envelope bridges, suggesting that Kar5p is required after outer nuclear envelope fusion. Finally, a split-GFP assay demonstrated that Kar5p localizes to both the inner and outer nuclear envelope. These insights suggest a mechanism by which Kar5p mediates inner nuclear membrane fusion. Copyright © 2015 Rogers and Rose.

  5. Elimination of zinc-65 from the brain under kainate-induced seizures.

    Science.gov (United States)

    Takeda, Atsushi; Hirate, Maki; Oku, Naoto

    2004-04-01

    On the basis of the previous evidence that 65Zn concentrations in the brain of EL (epilepsy) mice was affected by induction of seizures, 65Zn movement in the brain was quantitatively evaluated in ddY mice treated with kainate. Six days after intravenous injection of 65ZnCl2, mice were intraperitoneally injected with kainate (10 mg/kg x 6 times in 2 weeks). Myoclonic jerks were observed during treatment with kainate. Twenty days after 65Zn injection, 65Zn distribution in the brain was compared between the kainite-treated and control mice. 65Zn distribution in the brain of the kainate-treated mice was overall lower than in the control mice. 65Zn concentration was significantly decreased in the frontal cortex, hippocampal CA1, thalamus and hypothalamus by treatment with kainate. These results demonstrate that kainate-induced seizures are linked to decreased zinc concentrations in the brain.

  6. Synthesis and enantiopharmacology of new AMPA-kainate receptor agonists

    DEFF Research Database (Denmark)

    Conti, P; De Amici, M; De Sarro, G

    1999-01-01

    . The convulsant properties of all the compounds were evaluated in vivo on DBA/2 mice after icv injection. CIP-A showed a convulsant activity, measured as tonus and clonus seizures, 18-65 times higher than that produced by AMPA. It was also quite active after ip administration, since it induced seizures in mice...... at doses as low as 3.2 nmol/mouse. On the basis of the above-reported results we prepared and tested the enantiomers of CIP-A and CIP-B, obtained by reacting (S)-3,4-didehydroproline and (R)-3,4-didehydroproline, respectively, with ethoxycarbonylformonitrile oxide. In all the tests the S-form, CIP...

  7. Hippocampal N-methyl-d-aspartate and kainate binding in response to entorhinal cortex aspiration or 192 IgG-saporin lesions of the basal forebrain

    International Nuclear Information System (INIS)

    Gallagher, M.; Gill, T.M.; Shivers, A.; Nicolle, M.M.

    1997-01-01

    Lesion models in the rat were used to examine the effects of removing innervation of the hippocampal formation on glutamate receptor binding in that system. Bilateral aspiration of the entorhinal cortex was used to remove the cortical innervation of the hippocampal formation and the dentate gyrus. The subcortical input to the hippocampus from cholinergic neurons of the basal forebrain was lesioned by microinjection of the immunotoxin 192 IgG-saporin into the medial septum and vertical limb of diagonal band. After a 30-day postlesion survival, the effects of these lesions on N-methyl-d-aspartate-displaceable [ 3 H]glutamate and [ 3 H]kainate binding in the hippocampus were quantified using in vitro autoradiography. The bilateral entorhinal lesion induced a sprouting response in the dentate gyrus, measured by an increase in the width of [ 3 H]kainate binding. It also induced an increase in the density of [ 3 H]kainate binding in CA3 stratum lucidum and an increase in N-methyl-d-aspartate binding throughout the hippocampus proper and the dentate gyrus. The selective lesion of cholinergic septal input did not have any effect on hippocampal [ 3 H]kainate binding and induced only a moderate decrease in N-methyl-d-aspartate binding that was not statistically reliable.The entorhinal and cholinergic lesions were used as in vivo models of the degeneration of hippocampal input that occurs in normal aging and Alzheimer's disease. The results from the present lesion study suggest that some, but not all, of the effects on hippocampal [ 3 H]kainate and N-methyl-d-aspartate binding induced by the lesions are consistent with the status of binding to these receptors in aging and Alzheimer's disease. Consistent with the effects of aging and Alzheimer's disease is an altered topography of [ 3 H]kainate binding after entorhinal cortex lesion and a modest decline in N-methyl-d-aspartate binding after lesions of the cholinergic septal input to the hippocampus. (Copyright (c) 1997

  8. Quantum chemical study of agonist-receptor vibrational interactions for activation of the glutamate receptor.

    Science.gov (United States)

    Kubo, M; Odai, K; Sugimoto, T; Ito, E

    2001-06-01

    To understand the mechanism of activation of a receptor by its agonist, the excitation and relaxation processes of the vibrational states of the receptor should be examined. As a first approach to this problem, we calculated the normal vibrational modes of agonists (glutamate and kainate) and an antagonist (6-cyano-7-nitroquinoxaline-2,3-dione: CNQX) of the glutamate receptor, and then investigated the vibrational interactions between kainate and the binding site of glutamate receptor subunit GluR2 by use of a semiempirical molecular orbital method (MOPAC2000-PM3). We found that two local vibrational modes of kainate, which were also observed in glutamate but not in CNQX, interacted through hydrogen bonds with the vibrational modes of GluR2: (i) the bending vibration of the amine group of kainate, interacting with the stretching vibration of the carboxyl group of Glu705 of GluR2, and (ii) the symmetric stretching vibration of the carboxyl group of kainate, interacting with the bending vibration of the guanidinium group of Arg485. We also found collective modes with low frequency at the binding site of GluR2 in the kainate-bound state. The vibrational energy supplied by an agonist may flow from the high-frequency local modes to the low-frequency collective modes in a receptor, resulting in receptor activation.

  9. A subconvulsive dose of kainate selectively compromises astrocytic metabolism in the mouse brain in vivo

    DEFF Research Database (Denmark)

    Walls, Anne B; Eyjolfsson, Elvar M; Schousboe, Arne

    2014-01-01

    Despite the well-established use of kainate as a model for seizure activity and temporal lobe epilepsy, most studies have been performed at doses giving rise to general limbic seizures and have mainly focused on neuronal function. Little is known about the effect of lower doses of kainate on cere...

  10. A subconvulsive dose of kainate selectively compromises astrocytic metabolism in the mouse brain in vivo.

    Science.gov (United States)

    Walls, Anne B; Eyjolfsson, Elvar M; Schousboe, Arne; Sonnewald, Ursula; Waagepetersen, Helle S

    2014-08-01

    Despite the well-established use of kainate as a model for seizure activity and temporal lobe epilepsy, most studies have been performed at doses giving rise to general limbic seizures and have mainly focused on neuronal function. Little is known about the effect of lower doses of kainate on cerebral metabolism and particularly that associated with astrocytes. We investigated astrocytic and neuronal metabolism in the cerebral cortex of adult mice after treatment with saline (controls), a subconvulsive or a mildly convulsive dose of kainate. A combination of [1,2-(13)C]acetate and [1-(13)C]glucose was injected and subsequent nuclear magnetic resonance spectroscopy of cortical extracts was employed to distinctively map astrocytic and neuronal metabolism. The subconvulsive dose of kainate led to an instantaneous increase in the cortical lactate content, a subsequent reduction in the amount of [4,5-(13)C]glutamine and an increase in the calculated astrocytic TCA cycle activity. In contrast, the convulsive dose led to decrements in the cortical content and (13)C labeling of glutamate, glutamine, GABA, and aspartate. Evidence is provided that astrocytic metabolism is affected by a subconvulsive dose of kainate, whereas a higher dose is required to affect neuronal metabolism. The cerebral glycogen content was dose-dependently reduced by kainate supporting a role for glycogen during seizure activity.

  11. K/Ar dating of diagenetic illites

    International Nuclear Information System (INIS)

    Mizusaki, A.M.P.; Anjos, S.M.C. dos; Costa, M.G.F. da; Silva, O.B. da; Kawashita, K.

    1990-01-01

    Ascertaining the potassium/argon (K/Ar) age of diagenetic illites yields important information for hydrocarbon exploration since the growth of this mineral in the pores of sandstone reservoir and oil migration are interlinked events in the diagenetic evolution of rocks. Illite growth ceases as soon as hydrocarbons completely fill in rock pores, displacing interstitial water. By providing an estimate of the period when the illite formed, K/Ar dating can indirectly tells us when hydrocarbons entered the reservoir. Samples of oil-saturated sandstones collected from Carboniferous reservoirs of the Solimoes Basin reveal a diagenetic evolution consisting predominantly of quartz, calcite, and illite overgrowths. In the present study, illite was mechanically separated by repeating a series of ultrasonic baths and ultrasonic probes followed by high-speed centrifuging. Resultant fractions were analyzed by X-ray diffractometry to measure the illite content of each sample. The separated illite material was found to be composed of illite and ordered mixed layer illite-smectite with 80% illite layers. Separated fractions were dated radiometrically by the K/Ar method. Preliminary results indicate an average age of some 200 m.y., which marks the end of the diagenetic development of the illites of this area. (author)

  12. Kainate toxicity in energy-compromised rat hippocampal slices: differences between oxygen and glucose deprivation.

    Science.gov (United States)

    Schurr, A; Rigor, B M

    1993-06-18

    The effects of kainate (KA) on the recovery of neuronal function in rat hippocampal slices after hypoxia or glucose deprivation (GD) were investigated and compared to those of (R,S)-alpha-amino-3-hydroxy-5-methyl-4- isoxazoleproprionate (AMPA). KA and AMPA were found to be more toxic than either N-methyl-D-aspartate (NMDA), quinolinate, or glutamate, both under normal conditions and under states of energy deprivation. Doses as low as 1 microM KA or AMPA were sufficient to significantly reduce the recovery rate of neuronal function in slices after a standardized period of hypoxia or GD. The enhancement of hypoxic neuronal damage by both agonists could be partially blocked by the antagonist kynurenate, by the NMDA competitive antagonist AP5, and by elevating [Mg2+] in or by omitting Ca2+ from the perfusion medium. The AMPA antagonist glutamic acid diethyl ester was ineffective in preventing the enhanced hypoxic neuronal damage by either KA or AMPA. The antagonist of the glycine modulatory site on the NMDA receptor, 7-chlorokynurenate, did not block the KA toxicity but was able to block the toxicity of AMPA. 2,3-Dihydroxyquinoxaline completely blocked the KA- and AMPA-enhanced hypoxic neuronal damage. The KA-enhanced, GD-induced neuronal damage was prevented by Ca2+ depletion and partially antagonized by kynurenate but not by AP5 or elevated [Mg2+]. The results of the present study indicate that the KA receptor is involved in the mechanism of neuronal damage induced by hypoxia and GD, probably allowing Ca2+ influx and subsequent intracellular Ca2+ overload.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Cell cycle-dependent regulation of kainate-induced inward currents in microglia

    International Nuclear Information System (INIS)

    Yamada, Jun; Sawada, Makoto; Nakanishi, Hiroshi

    2006-01-01

    Microglia are reported to have α-amino-hydroxy-5-methyl-isoxazole-4-propionate/kainate (KA) types. However, only small population of primary cultured rat microglia (approximately 20%) responded to KA. In the present study, we have attempted to elucidate the regulatory mechanism of responsiveness to KA in GMIR1 rat microglial cell line. When the GMIR1 cells were plated at a low density in the presence of granulocyte macrophage colony-stimulating factor, the proliferation rate increased and reached the peak after 2 days in culture and then gradually decreased because of density-dependent inhibition. At cell proliferation stage, approximately 80% of the GMIR1 cells exhibited glutamate (Glu)- and KA-induced inward currents at cell proliferation stage, whereas only 22.5% of the cells showed responsiveness to Glu and KA at cell quiescent stage. Furthermore, the mean amplitudes of inward currents induced by Glu and KA at cell proliferation stage (13.8 ± 3.0 and 8.4 ± 0.6 pA) were significantly larger than those obtained at cell quiescent stage (4.7 ± 0.8 and 6.2 ± 1.2 pA). In the GMIR1 cells, KA-induced inward currents were markedly inhibited by (RS)-3-(2-carboxybenzyl) willardiine (UBP296), a selective antagonist for KA receptors. The KA-responsive cells also responded to (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a selective agonist for GluR5, in both GMIR1 cells and primary cultured rat microglia. Furthermore, mRNA levels of the KA receptor subunits, GluR5 and GluR6, at the cell proliferation stage were significantly higher than those at the cell quiescent stage. Furthermore, the immunoreactivity for GluR6/7 was found to increase in activated microglia in the post-ischemic hippocampus. These results strongly suggest that microglia have functional KA receptors mainly consisting of GluR5 and GluR6, and the expression levels of these subunits are closely regulated by the cell cycle mechanism

  14. Zooplankton abundance in the River Kars, Northeast Turkey: Impact ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... Turkey: Impact of environmental variables. H. Özbay1* and ... in the river. Key words: River Kars, zooplankton, running water, environmental factors. ..... tergestina (Branchiopoda: Onychopoda) in Guanabara Bay, Brazil. Braz.

  15. The effect of Vitamin E on learning and memory deficits in intrahippocampal kainate-induced temporal lobe epilepsy in rats.

    Science.gov (United States)

    Kiasalari, Zahra; Khalili, Mohsen; Shafiee, Samaneh; Roghani, Mehrdad

    2016-01-01

    Since temporal lobe epilepsy (TLE) is associated with learning and memory impairment, we investigated the beneficial effect of Vitamin E on the impaired learning and memory in the intrahippocampal kainate model of TLE in rats. Rats were divided into sham, Vitamin E-treated sham, kainate, and Vitamin E-treated kainate. Intrahippocampal kainate was used for induction of epilepsy. Vitamin E was injected intraperitoneal (i.p.) at a dose of 200 mg/kg/day started 1 week before surgery until 1 h presurgery. Initial and step-through latencies in the passive avoidance test and alternation behavior percentage in Y-maze were finally determined in addition to measurement of some oxidative stress markers. Kainate injection caused a higher severity and rate of seizures and deteriorated learning and memory performance in passive avoidance paradigm and spontaneous alternation as an index of spatial recognition memory in Y-maze task. Intrahippocampal kainate also led to the elevation of malondialdehyde (MDA) and nitrite and reduced activity of superoxide dismutase (SOD). Vitamin E pretreatment significantly attenuated severity and incidence rate of seizures, significantly improved retrieval and recall in passive avoidance, did not ameliorate spatial memory deficit in Y-maze, and lowered MDA and enhanced SOD activity. Vitamin E improves passive avoidance learning and memory and part of its beneficial effect is due to its potential to mitigate hippocampal oxidative stress.

  16. High Concentrations of Tranexamic Acid Inhibit Ionotropic Glutamate Receptors.

    Science.gov (United States)

    Lecker, Irene; Wang, Dian-Shi; Kaneshwaran, Kirusanthy; Mazer, C David; Orser, Beverley A

    2017-07-01

    The antifibrinolytic drug tranexamic acid is structurally similar to the amino acid glycine and may cause seizures and myoclonus by acting as a competitive antagonist of glycine receptors. Glycine is an obligatory co-agonist of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. Thus, it is plausible that tranexamic acid inhibits NMDA receptors by acting as a competitive antagonist at the glycine binding site. The aim of this study was to determine whether tranexamic acid inhibits NMDA receptors, as well as α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate subtypes of ionotropic glutamate receptors. Tranexamic acid modulation of NMDA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, and kainate receptors was studied using whole cell voltage-clamp recordings of current from cultured mouse hippocampal neurons. Tranexamic acid rapidly and reversibly inhibited NMDA receptors (half maximal inhibitory concentration = 241 ± 45 mM, mean ± SD; 95% CI, 200 to 281; n = 5) and shifted the glycine concentration-response curve for NMDA-evoked current to the right. Tranexamic acid also inhibited α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (half maximal inhibitory concentration = 231 ± 91 mM; 95% CI, 148 to 314; n = 5 to 6) and kainate receptors (half maximal inhibitory concentration = 90 ± 24 mM; 95% CI, 68 to 112; n = 5). Tranexamic acid inhibits NMDA receptors likely by reducing the binding of the co-agonist glycine and also inhibits α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid and kainate receptors. Receptor blockade occurs at high millimolar concentrations of tranexamic acid, similar to the concentrations that occur after topical application to peripheral tissues. Glutamate receptors in tissues including bone, heart, and nerves play various physiologic roles, and tranexamic acid inhibition of these receptors may contribute to adverse drug effects.

  17. Excitatory and inhibitory pathways modulate kainate excitotoxicity in hippocampal slice cultures

    DEFF Research Database (Denmark)

    Casaccia-Bonnefil, P; Benedikz, Eirikur; Rai, R

    1993-01-01

    In organotypic hippocampal slice cultures, kainate (KA) specifically induces cell loss in the CA3 region while N-methyl-D-aspartate induces cell loss in the CA1 region. The sensitivity of slice cultures to KA toxicity appears only after 2 weeks in vitro which parallels the appearance of mossy...... fibers. KA toxicity is potentiated by co-application with the GABA-A antagonist, picrotoxin. These data suggest that the excitotoxicity of KA in slice cultures is modulated by both excitatory and inhibitory synapses....

  18. Expression and localization of ionotropic glutamate receptor subunits in the goldfish retina--an in situ hybridization and immunocytochemical study

    NARCIS (Netherlands)

    Vandenbranden, C. A.; Kamphuis, W.; Nunes Cardozo, B.; Kamermans, M.

    2000-01-01

    The expression and distribution of AMPA, kainate and NMDA glutamate receptor subunits was studied in the goldfish retina. For the immunocytochemical localization of the AMPA receptor antisera against GluR2, GluR2/3 and GluR4 were used, and for in situ hybridization rat specific probes for GluR1 and

  19. Altkäemaksu vahendus (KarS § 296) kui vajaliku osavõtuga koosseis. Riigikohtu kriminaalkolleegiumi otsus 3-1-1-7-08 / Jaan Sootak

    Index Scriptorium Estoniae

    Sootak, Jaan, 1948-

    2008-01-01

    Riigikohtu kriminaalkolleegiumi otsusest 3-1-1-7-08. P. P. kaitsja vandeadvokaat Valentina Manjuki kassatsioon Viru Ringkonnakohtu 24. oktoobri 2007. a kohtuotsuse peale kriminaalasjas P. P. süüdistuses KarS § 296 lg 1 järgi

  20. Neuropeptide Y Y1 receptor hippocampal overexpression via viral vectors is associated with modest anxiolytic-like and proconvulsant effects in mice

    DEFF Research Database (Denmark)

    Olesen, Mikkel V; Christiansen, Søren Hofman Oliveira; Gøtzsche, Casper René

    2012-01-01

    overexpression was found to be associated with modest anxiolytic-like effect in the open field and elevated plus maze tests, but no effect was seen on depression-like behavior using the tail suspension and forced swim tests. However, the rAAV-Y1 vector modestly aggravated kainate-induced seizures. These data...... in the hippocampus of adult mice and tested the animals in anxiety- and depression-like behavior. Hippocampal Y1 receptors have been suggested to mediate seizure-promoting effect, so the effects of rAAV-induced Y1 receptor overexpression were also tested in kainate-induced seizures. Y1 receptor transgene...

  1. A pharmacological profile of the high-affinity GluK5 kainate receptor

    DEFF Research Database (Denmark)

    Møllerud, Stine; Kastrup, Jette Sandholm Jensen; Pickering, Darryl S

    2016-01-01

    -hydroxyisoxazol-4-yl)propionate (ATPA), dihydrokainate and (2 S,4 R)−4-methyl-glutamate (SYM2081) have higher affinity at GluK3 compared to GluK5. Since some studies have indicated that GluK5 is associated with various diseases in the central nervous system (e.g. schizophrenia, temporal lobe epilepsy, bipolar...

  2. Metabotropic action of postsynaptic kainate receptors triggers hippocampal long-term potentiation

    Czech Academy of Sciences Publication Activity Database

    Petrovič, Miloš; da Silva, S. V.; Clement, J. P.; Vyklický ml., Ladislav; Mulle, C.; González-González, I. M.; Henley, J. M.

    2017-01-01

    Roč. 20, č. 4 (2017), s. 529-539 ISSN 1097-6256 R&D Projects: GA ČR(CZ) GA17-02300S Institutional support: RVO:67985823 Keywords : hippocampus * long-term potentiation * membrane proteins Subject RIV: FH - Neurology OBOR OECD: Neuroscience s (including psychophysiology Impact factor: 17.839, year: 2016

  3. Identification of Checkpoint Genes Involved in the kar3 Cell Cycle Arrest

    National Research Council Canada - National Science Library

    Shanks, Robert

    2001-01-01

    ...) including Cik1p and Vik1p. We have explored the roles of these KAPs in mejosis. Cik1p is essential for meiosis, while Vik1p has a very minor role. These data are consistent with Cik1p and Kar3p acting together to perform the essential role of Kar3p in meiosis. We have also localized Kar3p, Cik1p,and Vik1p during meiosis.

  4. Hyperexcitability and cell loss in kainate-treated hippocampal slice cultures

    DEFF Research Database (Denmark)

    Benedikz, Eirikur; Casaccia-Bonnefil, P; Stelzer, A

    1993-01-01

    Loss of hippocampal interneurons has been reported in patients with severe temporal lobe epilepsy and in animals treated with kainate. We investigated the relationship between KA induced epileptiform discharge and loss of interneurons in hippocampal slice cultures. Application of KA (1 micro......M) produced reversible epileptiform discharge without neurotoxicity. KA (5 microM), in contrast, produced irreversible epileptiform discharge and neurotoxicity, suggesting that the irreversible epileptiform discharge was required for the neuronal loss. Loss of CA3 pyramidal cells and parvalbumin......-like immunoreactive (PV-I) interneurons preceded loss of somatostatin-like immunoreactive (SS-I) interneurons suggesting a different time course of KA neurotoxicity in these subpopulations of interneurons....

  5. Dose-Dependent Effect of Curcumin on Learning and Memory Deficit in Kainate-Epileptic Rats

    Directory of Open Access Journals (Sweden)

    Zahra Kiasalari

    2014-09-01

    Full Text Available Background & objectives : Epileptic seizures accompany disturbances in learning, memory, and cognitive skills. With regard to antiepileptic potential of curcumin and its beneficial effect on memory, the effect of its administration on learning and memory in kainate-epileptic rats was investigated.   Methods: Forty male rats were divided into sham, positive control ( valproate-treated epileptic, epileptic, and two curcumin-treated epileptic groups. Rat model of epilepsy was induced by unilateral intrahippocampal administration of 4 μg of kainate per rat. Rats received intraperitoneal injection of curcumin (50 and 100 mg/kg daily for 1 week before surgery. For evaluation of learning and memory, initial (IL and step-through latencies (STL were determined using passive avoidance test and alternation behavior percentage was obtained according to Y maze test.   Results: Regarding IL, there was no significant difference between the groups. In contrast, STL significantly decreased in curcumin-50-treated epileptic group (p<0.05 (a change from 263.1 to 184.5 s. However, this parameter significantly increased in curcumin-100-treated epileptic group as compared to epileptic group (p<0.01 (a change from 263.1 to 220.3 s. In addition, STL was also significantly higher in valproic acid-treated epileptic group versus epileptic group (p<0.05 (a change from 145.7 to 210.3 s. Alternation percentage was also significantly higher in curcumin-50- and curcumin-100-treated epileptic groups relative to epileptic group (p<0.05 (a change from 60.5 to 77.6 and 80.3%.   Conclusion: Curcumin could dose-dependently enhance the consolidation and recall in epileptic animals and could improve spatial memory in such animals.

  6. Glufosinate ammonium induces convulsion through N-methyl-D-aspartate receptors in mice.

    Science.gov (United States)

    Matsumura, N; Takeuchi, C; Hishikawa, K; Fujii, T; Nakaki, T

    2001-05-18

    Glufosinate ammonium, a broad-spectrum herbicide, causes convulsion in rodents and humans. Because of the structural similarities between glufosinate and glutamate, the convulsion induced by glufosinate ammonium may be ascribed to glutamate receptor activation. Three N-methyl-D-asparate (NMDA) receptor antagonists, dizocilpine, LY235959, and Compound 40, and an alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist, NBQX, were coadministrated with glufosinate ammonium (80 mg/kg, intraperitoneally) in mice. Statistical analyses showed that the NMDA receptor antagonists markedly inhibited the convulsions, while the AMPA/kainate receptor antagonist had no effect on the convulsion. These results suggest that the convulsion caused by glufosinate ammonium is mediated through NMDA receptors.

  7. Combined gene overexpression of neuropeptide Y and its receptor Y5 in the hippocampus suppresses seizures

    DEFF Research Database (Denmark)

    Gøtzsche, Casper René; Nikitidou, Litsa; Sørensen, Andreas Toft

    2012-01-01

    We recently demonstrated that recombinant adeno-associated viral vector-induced hippocampal overexpression of neuropeptide Y receptor, Y2, exerts a seizure-suppressant effect in kindling and kainate-induced models of epilepsy in rats. Interestingly, additional overexpression of neuropeptide Y...

  8. K-Ar ages of the Auckland geomagnetic excursions

    International Nuclear Information System (INIS)

    Mochizuki, Nobutatsu; Tsunakawa, Hideo; Shibuya, Hidetoshi; Tagami, Takahiro; Ozawa, Ayako; Cassidy, John; Smith, E.M.

    2004-01-01

    K-Ar age determinations were made on two monogenetic volcanoes in the Auckland volcanic field, New Zealand, which have recorded the Auckland geomagnetic excursions. For the Wiri volcano with the north-down intermediate paleomagnetic direction, five samples gave a weighted mean age of 27±5 (1σ) ka. For the Hampton Park volcano with the west-up intermediate direction, three samples gave a weighted mean of 55±5(1σ) ka. Since these two K-Ar ages are distinguished at 2σ level, it is inferred that at least two geomagnetic excursions can be recognized in Auckland. The age of the Hampton Park is barely distinguished from the established age range of the Laschamp excursion (39-45 ka) at 2σ level. The age of the Wiri coincides with the age of c. 30 ka in which excursions have been found from sedimentary and volcanic records. The reported excursions from volcanic rocks show a VGP cluster in the central to northern Pacific region which is distinct from the VGP paths or clusters during polarity reversals. (author)

  9. Visualization of spatiotemporal energy dynamics of hippocampal neurons by mass spectrometry during a kainate-induced seizure.

    Directory of Open Access Journals (Sweden)

    Yuki Sugiura

    Full Text Available We report the use of matrix-assisted laser desorption/ionization (MALDI imaging mass spectrometry combined with capillary electrophoresis (CE mass spectrometry to visualize energy metabolism in the mouse hippocampus by imaging energy-related metabolites. We show the distribution patterns of ATP, ADP, and AMP in the hippocampus as well as changes in their amounts and distribution patterns in a murine model of limbic, kainate-induced seizure. As an acute response to kainate administration, we found massive and moderate reductions in ATP and ADP levels, respectively, but no significant changes in AMP levels--especially in cells of the CA3 layer. The results suggest the existence of CA3 neuron-selective energy metabolism at the anhydride bonds of ATP and ADP in the hippocampal neurons during seizure. In addition, metabolome analysis of energy synthesis pathways indicates accelerated glycolysis and possibly TCA cycle activity during seizure, presumably due to the depletion of ATP. Consistent with this result, the observed energy depletion significantly recovered up to 180 min after kainate administration. However, the recovery rate was remarkably low in part of the data-pixel population in the CA3 cell layer region, which likely reflects acute and CA3-selective neural death. Taken together, the present approach successfully revealed the spatiotemporal energy metabolism of the mouse hippocampus at a cellular resolution--both quantitatively and qualitatively. We aim to further elucidate various metabolic processes in the neural system.

  10. A new potential AED, carisbamate, substantially reduces spontaneous motor seizures in rats with kainate-induced epilepsy

    Science.gov (United States)

    Grabenstatter, Heidi L.; Dudek, F. Edward

    2010-01-01

    Purpose Animal models with spontaneous epileptic seizures may be useful in the discovery of new antiepileptic drugs (AEDs). The purpose of the present study was to evaluate the efficacy of carisbamate on spontaneous motor seizures in rats with kainate-induced epilepsy. Methods Repeated, low-dose (5 mg/kg), intraperitoneal injections of kainate were administered every hour until each male Sprague-Dawley rat had experienced convulsive status epilepticus for at least 3 h. Five 1-month trials (n= 8–10 rats) assessed the effects of 0.3, 1, 3, 10 and 30 mg/kg carisbamate on spontaneous seizures. Each trial involved six AED-versus-vehicle tests comprised of carisbamate or 10% solutol-HS-15 treatments administered as intraperitoneal injections on alternate days with a recovery day between each treatment day. Results Carisbamate significantly reduced motor seizure frequency at doses of 10 and 30 mg/kg, and caused complete seizure cessation during the 6-h post-drug epoch in 7 of 8 animals at 30 mg/kg. The effects of carisbamate (0.3–30 mg/kg) on spontaneous motor seizures appeared dose dependent. Conclusions These data support the hypothesis that a repeated-measures, cross-over protocol in animal models with spontaneous seizures is an effective method for testing AEDs. Carisbamate reduced the frequency of spontaneous motor seizures in a dose-dependent manner, and was more effective than topiramate at reducing seizures in rats with kainate-induced epilepsy. PMID:18494790

  11. Disrupted Co-activation of Interneurons and Hippocampal Network after Focal Kainate Lesion

    Directory of Open Access Journals (Sweden)

    Lim-Anna Sieu

    2017-11-01

    Full Text Available GABAergic interneurons are known to control activity balance in physiological conditions and to coordinate hippocampal networks during cognitive tasks. In temporal lobe epilepsy interneuron loss and consecutive network imbalance could favor pathological hypersynchronous epileptic discharges. We tested this hypothesis in mice by in vivo unilateral epileptogenic hippocampal kainate lesion followed by in vitro recording of extracellular potentials and patch-clamp from GFP-expressing interneurons in CA3, in an optimized recording chamber. Slices from lesioned mice displayed, in addition to control synchronous events, larger epileptiform discharges. Despite some ipsi/contralateral and layer variation, interneuron density tended to decrease, average soma size to increase. Their membrane resistance decreased, capacitance increased and contralateral interneuron required higher current intensity to fire action potentials. Examination of synchronous discharges of control and larger amplitudes, revealed that interneurons were biased to fire predominantly with the largest population discharges. Altogether, these observations suggest that the overall effect of reactive cell loss, hypertrophy and reduced contralateral excitability corresponds to interneuron activity tuning to fire with larger population discharges. Such cellular and network mechanisms may contribute to a runaway path toward epilepsy.

  12. Changes in calcium and iron levels in the brains of rats during kainate induced epilepsy

    Science.gov (United States)

    Ren, Min-Qin; Ong, Wei-Yi; Makjanic, Jagoda; Watt, Frank

    1999-10-01

    Epilepsy is a recurrent disorder of cerebral function characterised by sudden brief attacks of altered consciousness, motor activity or sensory phenomena, and affects approximately 1% of the population. Kainic acid injection induces neuronal degeneration in rats, is associated with glial hypertrophy and proliferation in the CA3-CA4 fields of hippocampal complex, and is a model for temporal lobe epilepsy. In this study we have applied Nuclear Microscopy to the investigation of the elemental changes within the hippocampus and the cortex areas of the rat brain following kainate injection. Analyses of unstained freeze dried tissue sections taken at 1 day and 1, 2, 3 and 4 weeks following injection were carried out using the Nuclear Microscopy facility at the Research Centre for Nuclear Microscopy, National University of Singapore. Quantitative analysis and elemental mapping indicates that there are significant changes in the calcium levels and distributions in the hippocampus as early as 1 day following injection. Preliminary results indicate a rapid increase in cellular calcium. High levels of calcium can activate calcium dependent proteins and phospholipases. Activation of phospholipase A 2 can be harmful to surrounding neurons through free radical damage. In addition to observed increases in calcium, there was evidence of increases in iron levels. This is consistent with measurements in other degenerative brain disorders, and may signal a late surge in free radical production.

  13. Changes in calcium and iron levels in the brains of rats during kainate induced epilepsy

    International Nuclear Information System (INIS)

    Ren, M.-Q.; Ong, W.-Y.; Makjanic, Jagoda; Watt, Frank

    1999-01-01

    Epilepsy is a recurrent disorder of cerebral function characterised by sudden brief attacks of altered consciousness, motor activity or sensory phenomena, and affects approximately 1% of the population. Kainic acid injection induces neuronal degeneration in rats, is associated with glial hypertrophy and proliferation in the CA3-CA4 fields of hippocampal complex, and is a model for temporal lobe epilepsy. In this study we have applied Nuclear Microscopy to the investigation of the elemental changes within the hippocampus and the cortex areas of the rat brain following kainate injection. Analyses of unstained freeze dried tissue sections taken at 1 day and 1, 2, 3 and 4 weeks following injection were carried out using the Nuclear Microscopy facility at the Research Centre for Nuclear Microscopy, National University of Singapore. Quantitative analysis and elemental mapping indicates that there are significant changes in the calcium levels and distributions in the hippocampus as early as 1 day following injection. Preliminary results indicate a rapid increase in cellular calcium. High levels of calcium can activate calcium dependent proteins and phospholipases. Activation of phospholipase A 2 can be harmful to surrounding neurons through free radical damage. In addition to observed increases in calcium, there was evidence of increases in iron levels. This is consistent with measurements in other degenerative brain disorders, and may signal a late surge in free radical production

  14. K/Ar age dating of Oshnaviyeh plutonic complex

    International Nuclear Information System (INIS)

    Ghalamghash, J.; Vosoughi Abedini, M.; Bellon, H.; Emami, M.H.; Pourmafi, M.; Rashid, H.

    2003-01-01

    Oshnaviyeh plutonic complex, the western member of Urumiyeh-Golpayehgan intrusive plutons is located in northern part of Sanandaj-Sirjan zon. Oshnaviyeh plutonic complex, exposing in an area of about 700 km 2 , comprises 10 plutons that can be divided into three suites, i.e.,diorite,granite,and alkali syenite-alkali granite. Dioritic bodies are the oldest intrusive rocks of the region, which on the basis of the field study, their relative age of emplacement is estimated to be post-Jurassic and pre-miocene. However, with respect to the age of other similar intrusive bodies in Naghadeh area, they are most likely of post early cretaceous-pre miocene age. Hybrid intrusive rocks, occurring at the contact of dioritic and granitic rocks may suggest a simultaneous emplacement of both magmas. Syntetic pluton from alkali syenite-alkali granite has intruded dioritic and granitic rocks, in contrast, flourine bearing alkali granite pluton from this suite shows no contact with other igneous rocks in the area. K-Ar age determinations obtained on amphibole specimens from diorite suite are 91.9±2.3, 94.1±2.3 and 100±2.4 Ma, and on biotite specimens from granite suite are 100±1.5 to 98.9±1.5 Ma. Chronology study using same method on arfvedsonite specimens from syenite pluton shows 78.9±3.1, 79.6±1.9 and 81.7±2.0 Ma and on K-fled par samples of flourine bearing alkali granite pluton from the alkali syenite-alkali granite suite presents 76±3.4 and 77.1±1.8. Therefore, based on field evidence and K/Ar age dating, Oshnaviyeh plutonic complex presumably formed during two episodes: granite and diorite suites formed simultaneously at about 100 Ma, then plutons of alkali syenite-alkali granite suite emplaced at about 80 Ma

  15. Development of calcium-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors in cultured neocortical neurons visualized by cobalt staining

    DEFF Research Database (Denmark)

    Jensen, J B; Schousboe, A; Pickering, D S

    1998-01-01

    The developmental expression of calcium (Ca2+)-permeable alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate receptors in cultured neocortical neurons was evaluated by using cobalt uptake, a histochemical method that identifies cells expressing Ca2+-permeable, non-N-methyl-D-aspartate...

  16. K/Ar dating of the Eastern Rhodope Paleogene magmatism

    Energy Technology Data Exchange (ETDEWEB)

    Lilov, P.; Yanev, Y.; Marchev, P.

    1987-12-01

    Paleogene magmatic rocks from the Eastern Rhodope Mountains have seldom been an object of radiogeochronological studies and very few data are available from the geological literature. Until now their dating relied heavily on paleontological data from fossil-bearing sediments, alternating with the lava flows. However, there are also many cross bodies (extrusions, dikes and intrusions) as well as volcanic areas of no sediments or of fossil-free sediments which require the combined use of both methods. This paper aims at characterizing geochronologically the Eastern Rhodope Paleogene volcanism. The K/Ar method was used to date reference volcanoes (mostly with well-defined positions in the Paleogene sequence) associated with the various phases of volcanic activity, as well as some separate intrusive bodies. Nomenclature of volcanics followed the classification of the Soviet Petrographic Commission and that of Peccerillo and Taylor as supplemented by Marchey. The paper characterizes only two of the three main volcanic districts, the Momcilgrad-Arda and the Borovica districts. The third one, Susica district, has restricted exposures near the state boundary between Bulgari and Greece and was excluded from the study. The results obtained are compared with the geochronological scales proposed by Odin and Cavelier and Pomerol which correlate radiogeochronological and paleontological data (nannoplancton data included).

  17. Increased NMDA and AMPA receptor densities in the anterior cingulate cortex in schizophrenia

    International Nuclear Information System (INIS)

    Zavitsanou, K.; Huang, X.-F.

    2002-01-01

    Full text: The anterior cingulate cortex (ACC) is a brain area of potential importance to our understanding of the pathophysiology of schizophrenia. Since a disturbed balance between excitatory and inhibitory activity is suggested to occur in the ACC in schizophrenia, the present study has focused on the analysis of binding of [ 3 H]MK801, [ 3 H]AMPA and [ 3 H]kainate, radioligands which respectively label the NMDA, AMPA and kainate receptors of the ionotropic glutamate receptor family in the ACC of 10 schizophrenia patients and 10 matched controls, using quantitative autoradiography. AMPA receptor densities were higher in cortical layer II whereas NMDA receptor densities were higher in cortical layers II-III in the ACC of both control and schizophrenia group. In contrast, kainate receptors displayed the highest density in cortical layer V. [ 3 H]AMPA binding was significantly increased by 25% in layer II in the schizophrenia group as compared to the control group. Similarly, a significant 17% increase of [ 3 H]MK801 binding was observed in layers II-III in the schizophrenia group. No statistically significant differences were observed for [ 3 H] kainate binding between the two groups. These results suggest that ionotropic glutamate receptors are differentially altered in the ACC of schizophrenia. The increase in [ 3 H]AMPA and [ 3 H]MK801 binding points to a postsynaptic compensation for impaired glutamatergic neurotransmission in the ACC in schizophrenia. Such abnormality could lead to an imbalance between the excitatory and inhibitory neurotransmission in this brain area that may contribute to the emergence of some schizophrenia symptoms. Copyright (2002) Australian Neuroscience Society

  18. Crystal structure of the Candida albicans Kar3 kinesin motor domain fused to maltose-binding protein

    International Nuclear Information System (INIS)

    Delorme, Caroline; Joshi, Monika; Allingham, John S.

    2012-01-01

    Highlights: ► The Candida albicans Kar3 motor domain structure was solved as a maltose-binding protein fusion. ► The electrostatic surface and part of the ATPase pocket of the motor domain differs markedly from other kinesins. ► The MBP–Kar3 interface highlights a new site for intramolecular or intermolecular interactions. -- Abstract: In the human fungal pathogen Candida albicans, the Kinesin-14 motor protein Kar3 (CaKar3) is critical for normal mitotic division, nuclear fusion during mating, and morphogenic transition from the commensal yeast form to the virulent hyphal form. As a first step towards detailed characterization of this motor of potential medical significance, we have crystallized and determined the X-ray structure of the motor domain of CaKar3 as a maltose-binding protein (MBP) fusion. The structure shows strong conservation of overall motor domain topology to other Kar3 kinesins, but with some prominent differences in one of the motifs that compose the nucleotide-binding pocket and the surface charge distribution. The MBP and Kar3 modules are arranged such that MBP interacts with the Kar3 motor domain core at the same site where the neck linker of conventional kinesins docks during the “ATP state” of the mechanochemical cycle. This site differs from the Kar3 neck–core interface in the recent structure of the ScKar3Vik1 heterodimer. The position of MBP is also completely distinct from the Vik1 subunit in this complex. This may suggest that the site of MBP interaction on the CaKar3 motor domain provides an interface for the neck, or perhaps a partner subunit, at an intermediate state of its motile cycle that has not yet been observed for Kinesin-14 motors.

  19. Crystal structure of the Candida albicans Kar3 kinesin motor domain fused to maltose-binding protein

    Energy Technology Data Exchange (ETDEWEB)

    Delorme, Caroline; Joshi, Monika [Department of Biomedical and Molecular Sciences, Queen' s University, Kingston, ON, Canada K7L 3N6 (Canada); Allingham, John S., E-mail: allinghj@queensu.ca [Department of Biomedical and Molecular Sciences, Queen' s University, Kingston, ON, Canada K7L 3N6 (Canada)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer The Candida albicans Kar3 motor domain structure was solved as a maltose-binding protein fusion. Black-Right-Pointing-Pointer The electrostatic surface and part of the ATPase pocket of the motor domain differs markedly from other kinesins. Black-Right-Pointing-Pointer The MBP-Kar3 interface highlights a new site for intramolecular or intermolecular interactions. -- Abstract: In the human fungal pathogen Candida albicans, the Kinesin-14 motor protein Kar3 (CaKar3) is critical for normal mitotic division, nuclear fusion during mating, and morphogenic transition from the commensal yeast form to the virulent hyphal form. As a first step towards detailed characterization of this motor of potential medical significance, we have crystallized and determined the X-ray structure of the motor domain of CaKar3 as a maltose-binding protein (MBP) fusion. The structure shows strong conservation of overall motor domain topology to other Kar3 kinesins, but with some prominent differences in one of the motifs that compose the nucleotide-binding pocket and the surface charge distribution. The MBP and Kar3 modules are arranged such that MBP interacts with the Kar3 motor domain core at the same site where the neck linker of conventional kinesins docks during the 'ATP state' of the mechanochemical cycle. This site differs from the Kar3 neck-core interface in the recent structure of the ScKar3Vik1 heterodimer. The position of MBP is also completely distinct from the Vik1 subunit in this complex. This may suggest that the site of MBP interaction on the CaKar3 motor domain provides an interface for the neck, or perhaps a partner subunit, at an intermediate state of its motile cycle that has not yet been observed for Kinesin-14 motors.

  20. The Potassium-Argon Laser Experiment (KArLE): In Situ Geochronology for Planetary Robotic Missions

    Science.gov (United States)

    Cohen, Barbara

    2016-01-01

    The Potassium (K) - Argon (Ar) Laser Experiment (KArLE) will make in situ noble-gas geochronology measurements aboard planetary robotic landers and roverss. Laser-Induced Breakdown Spectroscopy (LIBS) is used to measure the K abun-dance in a sample and to release its noble gases; the evolved Ar is measured by mass spectrometry (MS); and rela-tive K content is related to absolute Ar abundance by sample mass, determined by optical measurement of the ablated volume. KArLE measures a whole-rock K-Ar age to 10% or better for rocks 2 Ga or older, sufficient to resolve the absolute age of many planetary samples. The LIBS-MS approach is attractive because the analytical components have been flight proven, do not require further technical development, and provide complementary measurements as well as in situ geochronology.

  1. Novel Functional Properties of Drosophila CNS Glutamate Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yan; Dharkar, Poorva; Han, Tae-Hee; Serpe, Mihaela; Lee, Chi-Hon; Mayer, Mark L.

    2016-12-01

    Phylogenetic analysis reveals AMPA, kainate, and NMDA receptor families in insect genomes, suggesting conserved functional properties corresponding to their vertebrate counterparts. However, heterologous expression of the Drosophila kainate receptor DKaiR1D and the AMPA receptor DGluR1A revealed novel ligand selectivity at odds with the classification used for vertebrate glutamate receptor ion channels (iGluRs). DKaiR1D forms a rapidly activating and desensitizing receptor that is inhibited by both NMDA and the NMDA receptor antagonist AP5; crystallization of the KaiR1D ligand-binding domain reveals that these ligands stabilize open cleft conformations, explaining their action as antagonists. Surprisingly, the AMPA receptor DGluR1A shows weak activation by its namesake agonist AMPA and also by quisqualate. Crystallization of the DGluR1A ligand-binding domain reveals amino acid exchanges that interfere with binding of these ligands. The unexpected ligand-binding profiles of insect iGluRs allows classical tools to be used in novel approaches for the study of synaptic regulation.

  2. Development of the Potassium-Argon Laser Experiment (KArLE) Instrument for In Situ Geochronology

    Science.gov (United States)

    Cohen, Barbara A.; Li, Z.-H.; Miller, J. S.; Brinckerhoff, W. B.; Clegg, S. M.; Mahaffy, P. R.; Swindle, T. D.; Wiens, R. C.

    2012-01-01

    Absolute dating of planetary samples is an essential tool to establish the chronology of geological events, including crystallization history, magmatic evolution, and alteration. Traditionally, geochronology has only been accomplishable on samples from dedicated sample return missions or meteorites. The capability for in situ geochronology is highly desired, because it will allow one-way planetary missions to perform dating of large numbers of samples. The success of an in situ geochronology package will not only yield data on absolute ages, but can also complement sample return missions by identifying the most interesting rocks to cache and/or return to Earth. In situ dating instruments have been proposed, but none have yet reached TRL 6 because the required high-resolution isotopic measurements are very challenging. Our team is now addressing this challenge by developing the Potassium (K) - Argon Laser Experiment (KArLE) under the NASA Planetary Instrument Definition and Development Program (PIDDP), building on previous work to develop a K-Ar in situ instrument [1]. KArLE uses a combination of several flight-proven components that enable accurate K-Ar isochron dating of planetary rocks. KArLE will ablate a rock sample, determine the K in the plasma state using laser-induced breakdown spectroscopy (LIBS), measure the liberated Ar using quadrupole mass spectrometry (QMS), and relate the two by the volume of the ablated pit using an optical method such as a vertical scanning interferometer (VSI). Our preliminary work indicates that the KArLE instrument will be capable of determining the age of several kinds of planetary samples to +/-100 Myr, sufficient to address a wide range of geochronology problems in planetary science.

  3. Glufosinate ammonium stimulates nitric oxide production through N-methyl D-aspartate receptors in rat cerebellum.

    Science.gov (United States)

    Nakaki, T; Mishima, A; Suzuki, E; Shintani, F; Fujii, T

    2000-09-01

    Glufosinate ammonium, a structural analogue of glutamate, is an active herbicidal ingredient. The neuronal activities of this compound were investigated by use of a microdialysis system that allowed us to measure nitric oxide production in the rat cerebellum in vivo. Kainate (0.3-30 nmol/10 microliter), N-methyl-D-aspartate (NMDA) (3-300 nmol/10 microliter) and glufosinate ammonium (30-3000 nmol/10 microliter), which were administered through the microdialysis probe at a rate of 1 microliter/min for 10 min, stimulated nitric oxide production. The glufosinate ammonium-elicited increase in nitric oxide production was suppressed by an inhibitor of nitric oxide synthase and was antagonized by NMDA receptor antagonists, but not by a kainate/(+/-)-alphaamino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor antagonist. These results suggest that glufosinate ammonium stimulates nitric oxide production through NMDA receptors.

  4. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  5. Aspects of dopamine and acetylcholine release induced by glutamate receptors

    International Nuclear Information System (INIS)

    Paes, Paulo Cesar de Arruda

    2002-01-01

    The basal ganglia play an important role in the motor control of rats and humans. This control involves different neurotransmitters and the mutual control of these key elements has been subject to several studies. In this work we determined the role of glutamate on the release of radioactively labelled dopamine and acetylcholine from chopped striatal tissue in vitro. The values of Effective Concentration 50% for glutamate, NMDA, kainic, quisqualic acids and AMPA on the release of dopamine and acetylcholine were obtained. The inhibitory effects of magnesium, tetrodotoxin, MK-801, AP5 and MCPG, as well as the effects of glycin were evaluated. The results suggested that dopamine is influenced by the NMDA type glutamate receptor while acetylcholine seems to be influenced by NMDA, kainate and AMPA receptors. Tetrodotoxin experiments suggested that kainate receptors are both present in cholinergic terminals and cell bodies while AMPA and NMDA receptors are preferentially distributed in cell bodies. Magnesium effectively blocked the NMDA stimulation and unexpectedly also AMPA- and quisqualate-induced acetylcholine release. The latter could not be blocked by MCPG ruling out the participation of methabotropic receptors. MK-801 also blocked NMDA-receptors. Results point out the importance of the glutamic acid control of dopamine and acetylcholine release in striatal tissue. (author)

  6. Transcriptome analyzis of germinatiing maize kernels exposed to smoke-water and active compound KAR1

    Czech Academy of Sciences Publication Activity Database

    Soós, V.; Sebestyén, E.; Juhász, A.; Light, M. E.; Kohout, Ladislav; Szalai, G.; Tandori, J.; van Staden, J.; Balázs, E.

    2010-01-01

    Roč. 10, č. 236 (2010), s. 1-15 ISSN 1471-2229 Institutional research plan: CEZ:AV0Z40550506 Keywords : smoke compound * transcriptome * KAR1 * butenolide Subject RIV: CC - Organic Chemistry Impact factor: 4.085, year: 2010

  7. Co-induction of p75(NTR) and the associated death executor NADE in degenerating hippocampal neurons after kainate-induced seizures in the rat.

    Science.gov (United States)

    Yi, Jung-Sun; Lee, Soon-Keum; Sato, Taka-Aki; Koh, Jae-Young

    2003-08-21

    Zinc induces in cultured cortical neurons both p75(NTR) and p75(NTR)-associated death executor (NADE), which together contribute to caspase-dependent neuronal apoptosis. Since zinc neurotoxicity may contribute to neuronal death following seizures, we examined whether p75(NTR) and NADE are co-induced also in rat hippocampal neurons degenerating after seizures. Staining of brain sections with a zinc-specific fluorescent dye (N-(6-methoxy-8-quinolyl)-p-carboxybenzoylsulphonamide) and acid fuchsin revealed zinc accumulation in degenerating neuronal cell bodies in CA1 and CA3 of hippocampus 24 h after kainate injection. Both anti-p75(NTR) and anti-NADE immunoreactivities appeared in zinc-accumulating/degenerating neurons in both areas. Intraventricular injection of CaEDTA, without altering the severity or time course of kainate-induced seizures, markedly attenuated the induction of p75(NTR)/NADE in hippocampus, which correlated with the decrease of caspase-3 activation and zinc accumulation/cell death. The present study has demonstrated that p75(NTR) and NADE are co-induced in neurons degenerating after kainate-induced seizures in rats, likely in a zinc-dependent manner.

  8. Update on Development of the Potassium-Argon Laser Experiment (KArLE) Instrument for In Situ Geochronology

    Science.gov (United States)

    Cohen, Barbara A.; Li, Z.-H.; Miller, J. S.; Brinckerhoff, W. B.; Clegg, S. M.; Mahaffy, P. R.; Swindle, T. D.; Wiens, R. C.

    2013-01-01

    Absolute dating of planetary samples is an essential tool to establish the chronology of geological events, including crystallization history, magmatic evolution, and alteration. We are addressing this challenge by developing the Potassium (K) -- Argon Laser Experiment (KArLE), building on previous work to develop a K-Ar in situ instrument. KArLE ablates a rock sample, determines the K in the plasma state using laser-induced breakdown spectroscopy (LIBS), measures the liberated Ar using quadrupole mass spectrometry (QMS), and relates the two by the volume of the ablated pit using laser confocal microscopy (LCM). Our goal is for the KArLE instrument to be capable of determining the age of several kinds of planetary samples to address a wide range of geochronolgy problems in planetary science.

  9. Arctigenin reduces neuronal responses in the somatosensory cortex via the inhibition of non-NMDA glutamate receptors.

    Science.gov (United States)

    Borbély, Sándor; Jócsák, Gergely; Moldován, Kinga; Sedlák, Éva; Preininger, Éva; Boldizsár, Imre; Tóth, Attila; Atlason, Palmi T; Molnár, Elek; Világi, Ildikó

    2016-07-01

    Lignans are biologically active phenolic compounds related to lignin, produced in different plants. Arctigenin, a dibenzylbutyrolactone-type lignan, has been used as a neuroprotective agent for the treatment of encephalitis. Previous studies of cultured rat cerebral cortical neurones raised the possibility that arctigenin inhibits kainate-induced excitotoxicity. The aims of the present study were: 1) to analyse the effect of arctigenin on normal synaptic activity in ex vivo brain slices, 2) to determine its receptor binding properties and test the effect of arctigenin on AMPA/kainate receptor activation and 3) to establish its effects on neuronal activity in vivo. Arctigenin inhibited glutamatergic transmission and reduced the evoked field responses. The inhibitory effect of arctigenin on the evoked field responses proved to be substantially dose dependent. Our results indicate that arctigenin exerts its effects under physiological conditions and not only on hyper-excited neurons. Furthermore, arctigenin can cross the blood-brain barrier and in the brain it interacts with kainate sensitive ionotropic glutamate receptors. These results indicate that arctigenin is a potentially useful new pharmacological tool for the inhibition of glutamate-evoked responses in the central nervous system in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. D-aspartate and NMDA, but not L-aspartate, block AMPA receptors in rat hippocampal neurons

    DEFF Research Database (Denmark)

    Gong, Xiang-Qun; Frandsen, Anne; Lu, Wei-Yang

    2005-01-01

    1 The amino acid, D-aspartate, exists in the mammalian brain and is an agonist at the N-methyl-D-aspartate (NMDA) subtype of ionotropic glutamate receptors. Here, for the first time, we studied the actions of D-aspartate on alpha-amino-3-hydroxyl-5-methyl-4-isoxazolepropionate receptors (AMPARs......) in acutely isolated rat hippocampal neurons. 2 In the presence of the NMDA receptor channel blocker, MK801, D-aspartate inhibited kainate-induced AMPAR current in hippocampal neurons. The inhibitory action of D-aspartate on kainate-induced AMPAR current was concentration-dependent and was voltage......-independent in the tested voltage range (-80 to +60 mV). 3 The estimated EC50 of the L-glutamate-induced AMPAR current was increased in the presence of D-aspartate, while the estimated maximum L-glutamate-induced AMPAR current was not changed. D-aspartate concentration-dependently shifted the dose-response curve of kainate...

  11. K/AR dating of clinoptilolite, mordenite, and associated clays from Yucca Mountains, Nevada

    International Nuclear Information System (INIS)

    WoldeGabriel, G.

    1993-01-01

    Zeolites are abundant in the geologic record in both continental and marine environments. The purpose of the present study is to evaluate the utility of K-bearing zeolites for dating by the K/Ar method to determine the time of zeolite diagenesis at Yucca Mountain, Nevada (Fig. 1). At Yucca Mountain, K-rich clinoptilolite and possibly mordenite are the only potentially K/Ar dateable secondary minerals present in the zeolite-rich tuffs except for some illite/smectites (≥10% illite layers) associated with these minerals. Direct dating of K-rich clinoptilolite, the most abundant zeolite in the altered tuffs, is important to delineate zeolite chronology as part of the site characterization of Yucca Mountain

  12. Eesti Maanteemuuseumi välialad = Estonian Road Museum, outdoor areas / Ralf Lõoke, Karli Luik, Maarja Kask ; intervjueerinud Margit Mutso

    Index Scriptorium Estoniae

    Lõoke, Ralf, 1978-

    2011-01-01

    Arhitektid: Maarja Kask, Karli Luik, Ralf Lõoke, Pelle-Sten Viiburg (Salto AB). Näituse kujundajad: Malle Jürgenson, Tea Tammelaan, Krista Lepland (Laika, Belka & Strelka). Maarja Kask, Karli Luik ja Ralf Lõoke pälvisid Eesti Kultuurkapitali aastapreemia (2010) kõrgetasemelise panuse eest Eesti maa-arhitektuuri: Eesti Maanteemuuseumi välialad (kaasautor Pelle-Sten Viiburg), Sõmeru keskushoone (kaasautorid Kristiina Arusoo ja Margit Argus)

  13. K-Ar ages for the Yahazudake volcanic rocks from southwest Kyushu, Japan; Kyushu nanseibu yahazudake kazanganrui no K-Ar nendai

    Energy Technology Data Exchange (ETDEWEB)

    Yokose, H.; Kikuchi, W. [Kumamoto Univ. (Japan)] Nagao, K. [Okayama Univ. (Japan)264000] Kodama, K. [Kochi Univ. (Japan)

    1998-05-05

    Many volcanic rocks, seemed to be erupted during the period from the Pliocene epoch to the Pleistocene epoch, are distributed abounding in Kyushu, Japan. In this study, K-Ar ages determination about the 4 samples which represents the Hisatsu volcanic rocks distributed around Yahazudake and rhyolite distributed in Gesujima placed in the southernmost extremity of Amakusa Shimojima, was conducted. And consideration of time/space distribution of the Hisatsu volcanic rocks upon collecting the data which were reported until now and the data obtained by the present K-Ar age determination, was done. In the result of the present measurement, the absolute age of the Hisatsu volcanic rocks distributed around Minamata-shi became clear. I was clarified that Yahazudake volcanic rocks consisted of andesite, which is comparatively lacking in potassium, were formed during about 100 thousand years from 1.98 to 2.08 Ma, and Ontake volcanic rocks which exists for the bottom erupted at about 2.15 Ma. And, the age value of 2.89 Ma was obtained from Ushibuka rhyolite distributed in Gesujima. 35 refs., 4 figs., 3 tabs.

  14. Dating of retrograde metamorphism in Western Carpathians by K-Ar analysis of muscovites

    International Nuclear Information System (INIS)

    Cambel, B.; Korikovskij, S.P.; Krasivskaya, I.S.; Arakelyants, M.M.

    1986-01-01

    Using the K-Ar isotope dating method of muscovites it was found that many retrogradely metamorphosed rocks are the results of Variscan retrograde metamorphism and are not pre-Cambrian or Alpine metamorphites (diaphthorites). Samples for dating were taken from the Western Carpathian crystalline formation. The content of radiogenic argon was determined by mass spectrometry using the method of isotope dilution. (M.D.)

  15. Revisions of K/Ar ages for the Hadar hominid site, Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Walter, R.C.; Aronson, J.L. (Case Western Reserve Univ., Cleveland, OH (USA). Dept. of Geology)

    1982-03-11

    Conventional K/Ar age measurements are reported for two volcanic units from the hominid-bearing Hadar Formation. These ages represent revision of previously published ages for the BKT-2 tephra and the Kadada Moumou basalt. BKT-2 is revised from 2.65 to 2.9 Myr BP and the Kadada Moumou basalt is revised from 3.0 to 3.6 Myr BP.

  16. Single Chondrule K/Ar ages of Mexican Meteorites Using ID-TIMS.

    Science.gov (United States)

    Hernandez, M.; Sole, J.

    2007-05-01

    We have determined the K/Ar ages of two H5 ordinary meteorites: Cosina and Nuevo Mercurio, neither dated until this study. We analyzed several single chondrules - weighing few milligrams - of each meteorite. Ages were obtained by using very precise K content determined by isotope dilution mass spectrometry. The K content in chondrules ranges between 650 and 1400 ppm. The 40Ar was measured by static vacuum noble gas mass spectrometry. Samples were fused with an infrared CO2 laser. Chondrule ages vary from 3.66 to 4.59 Ga for Cosina and from 4.20 to 4.87 Ga for Nuevo Mercurio. A comparison between our data and the published K/Ar ages of H and L whole rocks shows that dates obtained from single chondrules are older than those obtained from whole rocks and seem to preserve older events not evidenced in the WR ages. This implies that chondrules can preserve K/Ar ages very close to U-Pb crystallization ages.

  17. Ablation of NMDA receptors enhances the excitability of hippocampal CA3 neurons.

    Directory of Open Access Journals (Sweden)

    Fumiaki Fukushima

    Full Text Available Synchronized discharges in the hippocampal CA3 recurrent network are supposed to underlie network oscillations, memory formation and seizure generation. In the hippocampal CA3 network, NMDA receptors are abundant at the recurrent synapses but scarce at the mossy fiber synapses. We generated mutant mice in which NMDA receptors were abolished in hippocampal CA3 pyramidal neurons by postnatal day 14. The histological and cytological organizations of the hippocampal CA3 region were indistinguishable between control and mutant mice. We found that mutant mice lacking NMDA receptors selectively in CA3 pyramidal neurons became more susceptible to kainate-induced seizures. Consistently, mutant mice showed characteristic large EEG spikes associated with multiple unit activities (MUA, suggesting enhanced synchronous firing of CA3 neurons. The electrophysiological balance between fast excitatory and inhibitory synaptic transmission was comparable between control and mutant pyramidal neurons in the hippocampal CA3 region, while the NMDA receptor-slow AHP coupling was diminished in the mutant neurons. In the adult brain, inducible ablation of NMDA receptors in the hippocampal CA3 region by the viral expression vector for Cre recombinase also induced similar large EEG spikes. Furthermore, pharmacological blockade of CA3 NMDA receptors enhanced the susceptibility to kainate-induced seizures. These results raise an intriguing possibility that hippocampal CA3 NMDA receptors may suppress the excitability of the recurrent network as a whole in vivo by restricting synchronous firing of CA3 neurons.

  18. Aspects of dopamine and acetylcholine release induced by glutamate receptors; Aspectos das liberacoes de dopamina e acetilcolina mediadas por receptores de glutamato

    Energy Technology Data Exchange (ETDEWEB)

    Paes, Paulo Cesar de Arruda

    2002-07-01

    The basal ganglia play an important role in the motor control of rats and humans. This control involves different neurotransmitters and the mutual control of these key elements has been subject to several studies. In this work we determined the role of glutamate on the release of radioactively labelled dopamine and acetylcholine from chopped striatal tissue in vitro. The values of Effective Concentration 50% for glutamate, NMDA, kainic, quisqualic acids and AMPA on the release of dopamine and acetylcholine were obtained. The inhibitory effects of magnesium, tetrodotoxin, MK-801, AP5 and MCPG, as well as the effects of glycin were evaluated. The results suggested that dopamine is influenced by the NMDA type glutamate receptor while acetylcholine seems to be influenced by NMDA, kainate and AMPA receptors. Tetrodotoxin experiments suggested that kainate receptors are both present in cholinergic terminals and cell bodies while AMPA and NMDA receptors are preferentially distributed in cell bodies. Magnesium effectively blocked the NMDA stimulation and unexpectedly also AMPA- and quisqualate-induced acetylcholine release. The latter could not be blocked by MCPG ruling out the participation of methabotropic receptors. MK-801 also blocked NMDA-receptors. Results point out the importance of the glutamic acid control of dopamine and acetylcholine release in striatal tissue. (author)

  19. (R-[11C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

    Directory of Open Access Journals (Sweden)

    Lammertsma Adriaan A

    2011-01-01

    Full Text Available Abstract Background Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp expression and functionality at an early stage after induction of status epilepticus by kainate. Methods (R-[11C]verapamil, which is currently the most frequently used positron emission tomography (PET ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R-[11C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R-[11C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles as well as by population mixed effects modelling (NONMEM. Results All data analysis approaches indicated only modest differences in brain distribution of (R-[11C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. Conclusions P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.

  20. (R)-[{sup 11}C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

    Energy Technology Data Exchange (ETDEWEB)

    Syvänen, Stina [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Luurtsema, Gert [Department of Nuclear Medicine & Molecular Imaging, Groningen University Medical Center, P.O. Box 30.001 9700 RB Groningen (Netherlands); Molthoff, Carla FM; Windhorst, Albert D; Huisman, Marc C; Lammertsma, Adriaan A [Department of Nuclear Medicine & PET Research, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam (Netherlands); Voskuyl, Rob A [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Epilepsy Institute of The Netherlands Foundation (SEIN), P.O. Box 21, 2100 AA, Heemstede (Netherlands); Lange, Elizabeth C de [Division of Pharmacology, LACDR, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands)

    2011-01-03

    Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate. (R)-[{sup 11}C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[{sup 11}C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[{sup 11}C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM). All data analysis approaches indicated only modest differences in brain distribution of (R)-[{sup 11}C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.

  1. (R)-[11C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

    International Nuclear Information System (INIS)

    Syvänen, Stina; Luurtsema, Gert; Molthoff, Carla FM; Windhorst, Albert D; Huisman, Marc C; Lammertsma, Adriaan A; Voskuyl, Rob A; Lange, Elizabeth C de

    2011-01-01

    Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate. (R)-[ 11 C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on (R)-[ 11 C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. (R)-[ 11 C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM). All data analysis approaches indicated only modest differences in brain distribution of (R)-[ 11 C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats. P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate

  2. Kainate-enhanced release of D-(3H)aspartate from cerebral cortex and striatum: reversal by baclofen and pentobarbital

    Energy Technology Data Exchange (ETDEWEB)

    Potashner, S.J.; Gerard, D.

    1983-06-01

    A study was made of the actions of the excitant neurotoxin, kainic acid, on the uptake and the release of D-(2,3-3H)aspartate (D-ASP) in slices of guinea pig cerebral neocortex and striatum. The slices took up D-ASP, reaching concentrations of the amino acid in the tissue which were 14-23 times that in the medium. Subsequently, electrical stimulation of the slices evoked a Ca2+-dependent release of a portion of the D-ASP. Kainic acid (10(-5)-10(-3) M) produced a dose-dependent inhibition of D-ASP uptake. The electrically evoked release of D-ASP was increased 1.6-2.0 fold by 10(-5) and 10(-4)M kainic acid. The kainate-enlarged release was Ca2+-dependent. Dihydrokainic acid, an analogue of kainic acid with little excitatory or toxic action, did not increase D-ASP release but depressed D-ASP uptake. Attempts were made to block the action of kainic acid with baclofen and pentobarbital, compounds which depress the electrically evoked release of L-glutamate (L-GLU) and L-aspartate (L-ASP). Baclofen (4 X 10(-6)M), an antispastic drug, and pentobarbital (10(-4)M), an anesthetic agent, each inhibited the electrically evoked release of D-ASP and prevented the enhancement of the release above control levels usually produced by 10(-4)M kainic acid. It is proposed that 10(-5) and 10(-4)M kainic acid may enhance the synaptic release of L-GLU and L-ASP from neurons which use these amino acids as transmitters. This action is prevented by baclofen and pentobarbital. In view of the possibility that cell death in Huntington's disease could involve excessive depolarization of striatal and other cells by glutamate, baclofen might be effective in delaying the loss of neurons associated with this condition.

  3. In Situ Dating Experiments of Igneous Rocks Using the KArLE Instrument: A Case Study for Approximately 380 Ma Basaltic Rocks

    Science.gov (United States)

    Cho, Yuichiro; Cohen, Barbara A.

    2018-01-01

    We report new K-Ar isochron data for two approximately 380 Ma basaltic rocks, using an updated version of the Potassium-Argon Laser Experiment (KArLE). These basalts have K contents comparable to lunar KREEP basalts or igneous lithologies found by Mars rovers, whereas previous proof-of-concept studies focused primarily on more K-rich rocks. We continue to measure these analogue samples to show the advancing capability of in situ K-Ar geochronology. KArLE is applicable to other bodies including the Moon or asteroids.

  4. K-Ar age of the Tertiary volcanic rocks in the Tohoku area, Japan

    International Nuclear Information System (INIS)

    Konda, Tadashi; Ueda, Yoshio.

    1980-01-01

    The absolute age of the Tertiary volcanic rocks in Tohoku area has been estimated by K-Ar method. The results are: (1) in case of the volcanic rocks of Monzen-Aikawa stage, 32.8 - 38.5 m.y.B.P., (2) in case of the volcanic rocks of Nozaki-Daijima stage, 22.0 - 25.1 m.y.B.P., (3) in case of the volcanic rocks of Nishikurosawa stage, 15.5 - 16.5 m.y.B.P., (4) in case of the volcanic rocks of Onnagawa stage, 12.6 - 14.8 m.y.B.P., (5) in case of the volcanic rocks of Funakawa stage, 9.6 - 11.3 m.y.B.P., and (6) in case of the volcanic rocks of Kitaura stage, 6.9 - 9.0 m.y.B.P. The samples used are such as biotite and whole rocks. The eruption periods in Tertiary volcanic activities presumed by K-Ar method are geologically significant. In the measurements made on the same system of samples under same conditions, there was difference in the K-Ar ages between the Monzen-Aikawa and the Nozaki-Daijima stages, and it was significantly noteworthy. It is indicated that the volcanic rock activities in the former stage had took place before those in the latter stage. In the Tohoku arc of northern Japan, the simultaneity in initial volcanic activities is not seen in the direction across the arc. (J.P.N.)

  5. Problems in the K-Ar dating of Quaternary volcanic rocks younger than 1 Ma

    International Nuclear Information System (INIS)

    Takaoka, Nobuo

    1989-01-01

    The assumption that the 40 Ar/ 36 Ar ratio of Ar trapped in volcanic rocks at eruption is atmospheric often gives a large systematic error in the K-Ar dating of Quaternary volcanic rocks younger than 1 Ma. There are two possible sources of error, the existence of excess Ar and mass-fractionated, initial Ar. The major source of excess Ar is supposed to be magma. The 40 Ar/ 36 Ar ratio for magmatic Ar in the North-East Japan arc is tentatively estimated to be 340±10 from measurements of Ar in large phenocrysts separated from Quaternary volcanic rocks. Separation of phenocrysts is the most effective to decrease the systematic error caused by excess Ar. The mass-fractionation of initial Ar should give the 38 Ar/ 36 Ar ratio which was changed from the atmospheric ratio. This can be checked by determining the 38 Ar/ 36 Ar ratio in samples. Since the systematic error caused by the mass-fractionated, initial Ar increases greatly with the increasing atmospheric Ar correction, it is important to correct the result for the mass-fractionation. Correction formulae are given. The error sources other than those mentioned above are uncertainty in the blank correction and instabilities in the sensitivity of spectrometer and the Ar isotopic ratio measurement. In order to increase accuracy of the K-Ar age obtained, to check the systematic errors by measuring samples together with standard samples is of great importance in the K-Ar dating of very young volcanic rocks. (author)

  6. Stress state and movement potential of the Kar-e-Bas fault zone, Fars, Iran

    Science.gov (United States)

    Sarkarinejad, Khalil; Zafarmand, Bahareh

    2017-08-01

    The Kar-e-Bas or Mengharak basement-inverted fault is comprised of six segments in the Zagros foreland folded belt of Iran. In the Fars region, this fault zone associated with the Kazerun, Sabz-Pushan and Sarvestan faults serves as a lateral transfer zone that accommodates the change in shortening direction from the western central to the eastern Zagros. This study evaluates the recent tectonic stress regime of the Kar-e-Bas fault zone based on inversion of earthquake focal mechanism data, and quantifies the fault movement potential of this zone based on the relationship between fault geometric characteristics and recent tectonic stress regimes. The trend and plunge of σ 1 and σ 3 are S25°W/04°-N31°E/05° and S65°E/04°-N60°W/10°, respectively, with a stress ratio of Φ = 0.83. These results are consistent with the collision direction of the Afro-Arabian continent and the Iranian microcontinent. The near horizontal plunge of maximum and minimum principle stresses and the value of stress ratio Φ indicate that the state of stress is nearly strike-slip dominated with little relative difference between the value of two principal stresses, σ 1 and σ 2. The obliquity of the maximum compressional stress into the fault trend reveals a typical stress partitioning of thrust and strike-slip motion in the Kar-e-Bas fault zone. Analysis of the movement potential of this fault zone shows that its northern segment has a higher potential of fault activity (0.99). The negligible difference between the fault-plane dips of the segments indicates that their strike is a controlling factor in the changes in movement potential.

  7. El universo plástico y sensorial de la mano (Wong Kar Wai, 2004

    Directory of Open Access Journals (Sweden)

    Ana MELENDO CRUZ

    2014-10-01

    Full Text Available In this article, we show how Wong Kar Wai, heir to a filmography closely linked to cinematographic modernity, explores themes such as loneliness, melancholy, or self-absorption in his short film The Hand (2004. These themes, together with his study of geometry, saturated colours and pictorial qualities through the prism of metaphysical realism, give rise to purely optical, sonorous and tactile situations. In this way, the Chinese film director reveals, through the presence of a body fragment and metonymy, the colourful and sonorous textures that form the sensory-motor spaces of the underworld in which the story is set

  8. Rb/Sr and K/Ar dating of Slovakia's rocks, its possibilities and interpretation

    International Nuclear Information System (INIS)

    Cambel, B.; Bagdasaryan, G.P.; Gukasyan, P.Kh.; Veselskij, I.

    1979-01-01

    Nuclear geochronological data are evaluated and summarized into histograms. On the basis of an evaluation, the results are compared obtained using various methods (K/Ar, Rb/Sr and U-Th-Pb) and the age of rocks in West Carpathians determined. It is pointed out that the age determination is dependent on the geochemical state of the studied minerals and rocks. The obtained results confirm the palaeozoic age of the majority of rocks of West Carpathians. Direct nuclear geochronological evidence of precambrium rocks has not yet been obtained. (author)

  9. K-Ar dating: incomplete extraction of radiogenic argon from alkali feldspar - a comment

    International Nuclear Information System (INIS)

    Baksi, A.K.

    1984-01-01

    In a recent paper, McDowell (1983) discussed the difficulties involved in obtaining accurate K-Ar ages on alkali feldspar samples. These difficulties primarily stem from the fact that the feldspars melt at high temperatures and lack structural volatiles which could flush out all of the 40 Ar* from the viscous melt at temperatures below 1600 0 C. Evidently, if feldspar samples could be satisfactorily melted at lower temperatures by the use of a suitable flux, complete release of 40 Ar* should occur. McDowell (1983) also commented on the lack of a suitable feldspar standard sample for argon dating work. This comment will briefly address these two problems. (Auth.)

  10. A compilation of {sup 40}Ar-{sup 39} and K-Ar ages: report 25

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, P A [Geological Survey of Canada, Ottawa, ON (Canada); Roddick, J C

    1997-12-31

    Twenty-three {sup 40}Ar-{sup 39}Ar age determinations (including two potassium-argon analyses) carried out by the Geological Survey of Canada are reported. Each age determination is accompanied by a description of the rock and mineral concentrate used; brief interpretative comments regarding the geological significance of each age are also provided where possible. The experimental procedures employed are described in outline. An index of all Geological Survey of Canada K-Ar age determinations published in this format has been prepared using NTS quadrangles as the primary reference. (author). 6 refs., 2 tabs., 1 fig.

  11. Radiation-related retrograde hydrogen isotope and K-Ar exchange in clay minerals

    International Nuclear Information System (INIS)

    Halter, C.; Pagel, M.; Sheppard, S.M.F.; Weber, F.; Clauer, N.

    1987-01-01

    Hydrogen and oxygen isotope studies have been widely applied to characterize the origin of fluids during ore-foaming processes. The primary isotope record, however, may be disturbed by retrograde exchange reactions, thus complicating the interpretation of the data. The susceptibility of minerals to retrograde isotope and chemical exchange is variable, reflecting differences in the mechanism and rate of isotope exchange. Results are presented on deuterium depletion, K/Ar ages and H 2 O + content of illites associated with uranium mineralization from the Athabasca basin (Canada). (author)

  12. K-Ar age estimate for the KBS Tuff, East Turkana, Kenya

    International Nuclear Information System (INIS)

    McDougall, I.; Maier, R.; Sutherland-Hawkes, P.; Gleadow, A.J.W.

    1980-01-01

    Stone tools and numerous vertebrate fossils including hominids, have been found in close stratigraphic proximity to the KBS Tuff, whose age has been the subject of much debate. Concordant K-Ar ages, averaging 1.89 +- 0.01 Myr, are reported on anorthoclase phenocrysts from 13 pumice clasts collected from within the KBS Tuff or its correlatives. It is believed that this age is the best estimate currently available for the time of formation of this important marker horizon within the East Turkana Basin. (author)

  13. A compilation of 40Ar-39 and K-Ar ages: report 25

    International Nuclear Information System (INIS)

    Hunt, P.A.; Roddick, J.C.

    1996-01-01

    Twenty-three 40 Ar- 39 Ar age determinations (including two potassium-argon analyses) carried out by the Geological Survey of Canada are reported. Each age determination is accompanied by a description of the rock and mineral concentrate used; brief interpretative comments regarding the geological significance of each age are also provided where possible. The experimental procedures employed are described in outline. An index of all Geological Survey of Canada K-Ar age determinations published in this format has been prepared using NTS quadrangles as the primary reference. (author). 6 refs., 2 tabs., 1 fig

  14. Archaeogeophysical Studies in the Ruins of Kars-Ani (Turkey) in the 2009 Excavation Season

    Science.gov (United States)

    Hoskan, Nihan; Ahmet Yuksel, Fethi; Gorucu, Ziya; Coruhlu, Yasar

    2010-05-01

    The Ani ancient city, which is at 48 km distance to Kars (Turkey), is founded at the banks of the Arpacay River flowing in the vicinity of Turkey - Armenia border and is in the borders of Mevcut Ocakli Village. Recent studies show that the first settlement in Ani ancient city could be in the 5th millenium B.C.(Chalcolithic Period) and moreover, there were some buildings built in the Iron and Bronze Period. In the early 9th century, Ashot Msaker, who was Bagratuni dynasty (806-827), declared their first capital city at Bagaran, some 40 km south of Ani, and then transferred it to Kars in the year 929. In 961, King Ashot III (953-977) transferred the capital city from Kars to Ani. Ani expanded during the reign of King Smbat II (977-989). Recent research shows that by the early 11th century the population of Ani was over 100,000. After capture of Ashot, Ani surrendered to Byzantine controlled in 1045. A Greek governor was installed in the city. In 1064 a Seljuk Turkish army, headed by Sultan Alparslan, attacked and captured Ani. Then the Georgians captured Ani in 1124, 1161 and 1174. By the 14th century Ani was ruled by the Turkish dynasties, namely Jalayrids and the Kara Koyunlu. After the Persian Safavids ruled Ani, it became part of the Turkish Ottoman Empire in 1579. A small town remained within its walls until 1650 A.C. and it was completely abandoned by the middle of the 18th century. Examples of Sasani, Arabic, Armenian, and Seljuk architecture can be found among the Ani ruins. Ani is home to the first Turkish mosque built in Anatolia, namely Ebul Menucehr. The mosque was erected by the members of the Seljuk Dynasty in 1072. The first archaeological excavations were conducted at Ani in 1892. Since then, several archaeological excavations have been done in Ani. In the 2009 excavation season, magnetic methods were applied in Ani ruins to find the exact locations of the ruins. Magnetic Gradient Measurements were taken in front of Ebul Menucehr Mosque. After

  15. The laser microprobe dating drives K-Ar geochronology into a new milestone at the end of 20th century

    International Nuclear Information System (INIS)

    Mu Zhiguo; Gao Yongjun

    2001-01-01

    K-Ar age dating method is facing a serious challenge to its application due to that both Ar loss and Ar excess are widespread found even though it has been undergoing 50 years. In the latest few years of the 20th century, studies on K-Ar geochronology have been pushing on a new step as a sign of method perfected and precision enhanced. High precision and high resolution 40 Ar/ 39 Ar dating, can use in both micro-area and a single grain, extends dating limit into the historical realm. Applied range of K-Ar geochronology is getting bigger and bigger due to fine analytical techniques while solved geological problems are getting wider and wider

  16. Interactions of neurotoxins with non-NMDA glutamate receptors: an autoradiographic study

    International Nuclear Information System (INIS)

    Kuenig, G.; Niedermeyer, B.; Krause, F.; Hartmann, J.; Deckert, J.; Heinsen, H.; Beckmann, H.; Riederer, P.; Ransmayr, G.

    1994-01-01

    Neurotoxic substances are discussed to cause neurode-generation by acting as excitotoxins on glutamate receptors. We investigated the properties of L-beta-oxalyl-amino-alanine (L-BOAA) and 3,4,6-trihydroxyphenlyalanine (6-OH-Dopa) at the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) glutamate receptor and that of L-BOAA and domoic acid at the kainate glutamate receptor in human hippocampus. (3 H)AMPA binding in hippocampal subfields was inhibited by L-BOAA and 6-OH-Dopa with mean IC50-values in the low micromolar range. (3H)Kainate binding was inhibited by L-BOAA with similar potency as (3H)AMPA binding and by domoic acid with mean IC50-values in the low nanomolar range. These results support the notion that symptoms like anterograde amnesia and epileptic seizures seen in domoic acid intoxication and limbic symptoms, e.g. cognitive and mood impairment observed in neurolathyrism may be caused by excitotoxic action on non-NMDA receptors. The potent interaction of 6-OH-Dopa with the AMPA-receptor may point to a possible dopaminergic-glutamatergic interaction in the development of neurodegenerative diseases like Parkinson's and Huntington's disease. (author)

  17. El universo plástico y sensorial de La mano (Wong Kar Wai, 2004

    Directory of Open Access Journals (Sweden)

    Melendo, Ana

    2012-04-01

    Full Text Available En español: Con el presente artículo, queremos mostrar cómo Wong Kar Wai, heredero de un cine muy vinculado a la modernidad cinematográfica, plantea en el cortometraje La mano (2004 temas como la soledad, la actitud melancólica o la necesidad de ensimismamiento. Estos, junto al estudio de la geometría, los colores saturados y las calidades pictóricas, y bajo el prisma de un realismo metafísico, dan lugar a situaciones ópticas, sonoras y táctiles puras. Es así como en el film del cineasta chino se ponen de manifiesto, a través de la presencia del fragmento corporal y la metonimia, las texturas, coloreadas y sonoras, que configuran los espacios sensoriomotrices del submundo en el que acontece la historia. In english: In this article, we show how Wong Kar Wai, heir to a filmography closely linked to cinematographic modernity, explores themes such as loneliness, melancholy, or self-absorption in his short film The Hand (2004. These themes, together with his study of geometry, saturated colours and pictorial qualities through the prism of metaphysical realism, give rise to purely optical, sonorous and tactile situations. In this way, the Chinese film director reveals, through the presence of a body fragment and metonymy, the colourful and sonorous textures that form the sensory-motor spaces of the underworld in which the story is set.

  18. K-Ar geochronology of the Kulu-Mandi Belt, NW Himalaya, India

    International Nuclear Information System (INIS)

    Mehta, P.K.; Rex, D.C.

    1977-01-01

    The K-Ar dates of micas and whole rock amphibolites from the Kulu-Mandi Belt define two distinct groups, (1) 20 to 75 m. y., and (2) 277 to 366 m. y. Our data together with the other available K-Ar and Rb-Sr mineral and whole rock data, enable us to confirm three major events in the Himalaya, the Late Precambrian-Cambrian Assyntian (Cadomian) Orogenic cycle, the Late Palaeozoic Hercynian Magmatic-Epeirogenic cycle and the Late Cretaceous-Teritiary Himalayan Orogenic cycle. The mineral dating is significant for delineating different phases of the last i.e. the Himalayan Oregeny. The radiometric data, so far to hand, indicate that the main activity of the young, Himalayan metamorphism was probably around 50 to 70 m. y. (Late Cretaceous-Eocene) and this was followed by a major uplift during the 10 to 25 m. y. (Mid. Miocene) time, which was responsible for thrusting and formation of nappe structures in the Himalaya. (orig.) [de

  19. K-Ar age of bronzite-andesite from Choshi, Chiba Prefecture, Japan

    International Nuclear Information System (INIS)

    Tatsumi, Yoshiyuki; Ishizaka, Kyoichi

    1979-01-01

    The authors have forwarded the study on the activity period of Setouchi volcanic rocks and the research on Sanukitoid which characterizes it. It was already mentioned that the activity period of Setouchi volcanic rocks is only the middle period of Mid-cainozoic era, and that Setouchi volcanic rocks can be treated as one rock region. In this paper, the K-Ar age of bronzite-andesite in Choshi, Chiba Prefecture, is reported, which the authors think as the eastern end of Setouchi volcanic rock region. The outline of the geological features in the vicinity of Choshi is explained. The rock samples for the measurement were collected in May, 1978, in the reconstruction site of the fishing port. The rock samples were fresh, and the effects of degeneration, wathering and others were not observed. The K-Ar age of these bronzite-andesite was determined by Teledyne Isotopes Co. in commission. The determination of K and Ar was carried out on all rock samples twice respectively. The isotopic age of the bronzite-andesite in Choshi was 11.8 +- 0.6 m.y., and it was produced by the volcanic activity in the middle period of Mid-cainozoic era, same as the volcanic rocks of Setouchi. It is considered that the eastern end of Setouchi volcanic rock region is Choshi according to the results of chemical properties and isotopic age. (Kako, I.)

  20. Isochron reassessment of K-Ar dating from the West Carpathian crystalline complex

    International Nuclear Information System (INIS)

    Burchart, J.; Cambel, B.; Kral, J.

    1987-01-01

    Published K-Ar ages from the West Carpathian crystalline complex show an extreme dispersion of values. Therefore agreement of model data with Harper's (1970) isochron models was confronted and verified. On the basis of this analysis only a few numbers -isochron data which have real importance from the point of view of geological conditions - can be presented: 1. 394±24 m.y. -amphiboles, Male Karpaty Mts.; 2. 265±18 m.y. - amphiboles, gemerides; 3. 302±40 m.y. - biotites, core mountains; 4. 94±18 m.y. - biotites, veporides. Only isochron K-Ar ages of amphiboles approximate the time of their recrystallization. Isochron ages of biotites belong to the category of cooling ages and they represent the period since transition through isotherm of ca. 270 degC. The results of muscovite and feldspar dating cannot be interpreted by Harper's models. A substantial part of analyzed material is represented by analyses of whole rocks which are inapplicable to geochronological purposes. (author). 15 figs., 4 tabs., 53 refs

  1. Rb/Sr and K/Ar determinations of Monguba and Pendanga rocks,Ceara

    International Nuclear Information System (INIS)

    Torquato, J.R.F.; Pedreira, L.H.; Kawashita, K.; Barbosa, H.S.P.

    1986-01-01

    In this paper we describe the petrography and geochronology of rocks from two quarries near the City of Fortaleza/Ceara. One, the Pedreira Monguba, is formed, basically, by rocks of the granitic to monzogranitic type. Its isochrone age is 672 +- 46 m.y. with an initial ratio of 0.7036 +- 0.0005. Datinfs of biotite by the K/Ar method gave values of 522+- 19m.y. for the consolidation of the region. For comparison with the other components of the same morphologic unit, the Massif of Maranguape, we designed a reference isochrone with all values available from the literature (for granite, gneisses and migmatites) and obtained a straight line parallel to the first, but with a higher initial ratio of 0.709, demonstrating the strong influence of the Brasiliano Cycle in this region. The other quarry, Pedreira Pendanga, is composed of gneisses and migmatized gneisses and forms an open chemical system. It was possible, however, to verify that its age is equal or greater than 2150+- 71 m.y. and that all of its rocks have suffered strong metamorphism during the Brasiliano Cycle as in shown by the K/Ar ages of biotites of 541+- 3 m.y. A discussion of sampling problems is given and the influence of a granitic intrusion on the chemical opening of the system is evidenced. (author) [pt

  2. Regional elevation history from Ribeira belt based in K-Ar dating

    International Nuclear Information System (INIS)

    Zimbres, E.; Kawashita, K.; Motoki, A.

    1990-01-01

    The Ribeira orogenic belt, Brazilian cycle in metamorphism, has biotite K-Ar ages becoming young from the border (600 Ma) to the central axis (450 Ma), these ages are not related to rock type nor intrusive phase, but to occurrence area. The fact suggests that this wide-ranging age distribution is not due to later thermal events, e.g. post tectonic intrusion, but to slow cooling on the axis zone. The climax metamorphic condition have been estimated as 675 sup(0)C and 4 to 5 kb (18 km's depth). This temperature is much higher than that of biotite argon retention (310 sup(0)C). These data indicate that the biotite K-Ar clock have been set fairly after the climax during regional uplift at a depth much shallower that the metamorphism. Biotite clock setting depth (310 sup(0)C) is calculated as 7.5 km, using geothermal gradient of 30 sup(0)C/km. In this connection, uplift of 11.5 km from 600 Ma to 450 Ma (rate of 77 m/m.y.) is estimated. Fission track datings in apatite (110 Ma), combined with a present geothermal gradient (25 sup(0)C/km) indicate uplift of 3.5 km from 450 Ma to 110 Ma (16 m/m.y.) and 4 km from 110 Ma to the present (35 m/m.y.). (author)

  3. K-Ar and Rb-Sr dating results of the Malyshevsky leucogranite massif (eastern slope of the Middle Urals)

    International Nuclear Information System (INIS)

    Smirnov, V.N.; Ivanov, K.S.; Ronkin, Yu.L.; Levin, V.Ya.; Bushlyakov, I.N.; Lepikhina, O.P.; Popova, O.Yu.

    2005-01-01

    The age of leucogranites and minerals forming the Malyshevsky massif was identified by the methods of K-Ar- and Rb-Sr dating for refining the sequence of magmatic complexes formation on the eastern slope of the Middle Urals. The obtained isotope age values, i.e. 229-277 mln. years (K-Ar) and 277.1±1.1 mln. years (Rb-Sr), permit considering the age of 277 mln. years as the period of the leucogranites formation and of the associated molybdenum mineralization [ru

  4. Erratum Aldosterone synthase C-344T, angiotensin II type 1 receptor ...

    Indian Academy of Sciences (India)

    Aldosterone synthase C-344T, angiotensin II type 1 receptor A1166C and 11-β hydroxysteroid dehydrogenase G534A gene polymorphisms and essential hypertension in the population of Odisha, India. Manisha Patnaik, Pallabi Pati, Surendra N. Swain, Manoj K. Mohapatra, Bhagirathi Dwibedi, Shantanu K. Kar.

  5. Preliminary assessment of clinoptilolite K/Ar results from Yucca Mountain, Nevada: A potential high-level radioactive waste repository site

    International Nuclear Information System (INIS)

    WoldeGabriel, G.; Bish, D.L.; Broxton, D.E.; Chipera, S.J.

    1992-01-01

    At Yucca Mountain, evidence for at least three distinct temporal groups of clinoptilolites can be delineated from the preliminary K/Ar dates (2--3 Ma; 4--5 Ma; 7--11 Ma). The older K/Ar dates that are similar to published illite/smectite ages (9--12 Ma) may be crystallization ages, whereas the younger dates probably represent continued diagenetic reactions of older clinoptilolites with percolating fluids. The K/Ar dates increase with depth, suggesting minimal argon loss in the deeper samples. Internal consistency of the clinoptilolite K/Ar results at different levels within the drill holes suggest that dating of K-rich zeolites may provide useful information for assessing the zeolitization at Yucca Mountain. Variations in the K/Ar dates are probably related to Ar loss during dissolution of older clinoptilolites and to contamination by finely crystalline feldspars

  6. Two modes of regulation of the fatty acid elongase ELOVL6 by the 3-ketoacyl-CoA reductase KAR in the fatty acid elongation cycle.

    Directory of Open Access Journals (Sweden)

    Tatsuro Naganuma

    Full Text Available Fatty acids (FAs are diverse molecules, and such diversity is important for lipids to exert their functions under several environmental conditions. FA elongation occurs at the endoplasmic reticulum and produces a variety of FA species; the FA elongation cycle consists of four distinct enzyme reactions. For this cycle to be driven efficiently, there must exist coordinated regulation of protein components of the FA elongation machinery. However, such regulation is poorly understood. In the present study, we performed biochemical analyses using the FA elongase ELOVL6 and the 3-ketoacyl-CoA reductase KAR, which catalyze the first and second steps of the FA elongation cycle, respectively. In vitro FA elongation assays using membrane fractions demonstrated that ELOVL6 activity was enhanced ∼10-fold in the presence of NADPH, although ELOVL6 itself did not require NADPH for its catalysis. On the other hand, KAR does use NADPH as a reductant in its enzyme reaction. Activity of purified ELOVL6 was enhanced by ∼3-fold in the presence of KAR. This effect was KAR enzyme activity-independent, since it was observed in the absence of NADPH and in the KAR mutant. However, ELOVL6 enzyme activity was further enhanced in a KAR enzyme activity-dependent manner. Therefore, KAR regulates ELOVL6 via two modes. In the first mode, KAR may induce conformational changes in ELOVL6 to become structure that can undergo catalysis. In the second mode, conversion of 3-ketoacyl-CoA to 3-hydroxyacyl-CoA by KAR may facilitate release of the product from the presumed ELOVL6-KAR complex.

  7. The GABAA receptor agonist THIP is neuroprotective in organotypic hippocampal slice cultures

    DEFF Research Database (Denmark)

    Kristensen, Bjarne Winther; Noraberg, Jens; Zimmer, Jens

    2003-01-01

    The potential neuroprotective effects of the GABA(A) receptor agonists THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and muscimol, and the selective GluR5 kainate receptor agonist ATPA ((RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid), which activates GABAergic interneu......The potential neuroprotective effects of the GABA(A) receptor agonists THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and muscimol, and the selective GluR5 kainate receptor agonist ATPA ((RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid), which activates GABAergic...... interneurons, were examined in hippocampal slice cultures exposed to N-methyl-D-aspartate (NMDA). The NMDA-induced excitotoxicity was quantified by densitometric measurements of propidium iodide (PI) uptake. THIP (100-1000 microM) was neuroprotective in slice cultures co-exposed to NMDA (10 microM) for 48 h......, while muscimol (100-1000 microM) and ATPA (1-3 microM) were without effect. The results demonstrate that direct GABA(A) agonism can mediate neuroprotection in the hippocampus in vitro as previously suggested in vivo....

  8. Dopamine modulation of avoidance behavior in Caenorhabditis elegans requires the NMDA receptor NMR-1.

    Directory of Open Access Journals (Sweden)

    Melvin Baidya

    Full Text Available The nematode C. elegans utilizes a relatively simple neural circuit to mediate avoidance responses to noxious stimuli such as the volatile odorant octanol. This avoidance behavior is modulated by dopamine. cat-2 mutant animals that are deficient in dopamine biosynthesis have an increased response latency to octanol compared to wild type animals, and this defect can be fully restored with the application of exogenous dopamine. Because this avoidance behavior is mediated by glutamatergic signaling between sensory neurons and premotor interneurons, we investigated the genetic interactions between dopaminergic signaling and ionotropic glutamate receptors. cat-2 mutant animals lacking either the GLR-1 or GLR-2 AMPA/kainate receptors displayed an increased response latency to octanol, which could be restored via exogenous dopamine. However, whereas cat-2 mutant animals lacking the NMR-1 NMDA receptor had increased response latency to octanol they were insensitive to exogenous dopamine. Mutants that lacked both AMPA/kainate and NMDA receptors were also insensitive to exogenous dopamine. Our results indicate that dopamine modulation of octanol avoidance requires NMR-1, consistent with NMR-1 as a potential downstream signaling target for dopamine.

  9. Maailma arhitektuurifestival = World Architecture Festival / Ingrid Ruudi ; kommenteerinud Maarja Kask, Karli Luik, Ralf Lõoke, Indrek Allmann, Martin Aunin

    Index Scriptorium Estoniae

    Ruudi, Ingrid, 1978-

    2011-01-01

    Barcelonas 2.-4. nov. 2011 toimunud 4. Maailma arhitektuurifestivalist (WAF). Muljeid jagavad II vooru pääsenud eesti arhitektid Maarja Kask, Karli Luik ja Ralf Lõoke AB-st Salto (Põhuteater, Sõmeru keskus), Martin Aunin (Must maja Nõmmel), Indrek Allmann AB-st Pluss (poolautonoomne saun). Üldvõitja - Media-ICT Barcelonas (Cloud 9 / Enric Ruiz-Geli)

  10. K-Ar geology, geochemistry and geochronology from the Maria River region dikes, Parana State southeastern part, Brazil

    International Nuclear Information System (INIS)

    Silva Junior, Renato Oliveira da; Dall'Agnol, Roberto; Oliveira, Elson Paiva de

    1996-01-01

    The paper synthesizes the geological, petrographical, geochemical and geochronological data from the Maria River region dikes, situated at the southeastern part of the Para State, Brazil. It identifies five groups of dikes and determines the age of these dikes, through the Potassium-Argon (K-Ar) methodology

  11. Illite K-Ar dating of fault breccia samples from ONKALO underground research facility, Olkiluoto, Eurajoki, SW Finland

    International Nuclear Information System (INIS)

    Maenttaeri, I.; Mattila, J.; Zwingmann, H.; Todd, A.J.

    2007-08-01

    Illite K-Ar age determinations were done on five fault breccia samples from the ONKALO underground research facility, Olkiluoto, Eurajoki, S-W Finland. The XRD, SEM, and TEM studies and K-Ar analyses were done in John deLaeter Center in Mass Spectrometry at Curtin University, Perth, Western Australia. The <2 micron grain size fractions contain illite, chlorite, dickite, and quartz. All fractions had minor contamination phases comprising mainly of quartz but traces of K-feldspar contamination could be identified in all samples. The authigenic illite shows variable K concentrations. The illite contents of the ONK-PL68 and ONK-PL87 samples are the smallest. The K-Ar ages for the <2 micron fractions vary from ∼0.55 Ga to 1.38 Ga. The sample ONKPL68 yields a K-Ar age of 912 ± 18 Ma corresponding to a Neoproterozoic-Tonian age. This age can be roughly temporally linked with late events related to Sveconorwegian orogeny. Sample ONK-PL87 has a K-Ar age of 550 ± 11 Ma corresponding to a Neoproterozoic - Lower Cambrian age. The samples ONK-PL522 and ONK-PL901 sampled from the storage hall fault show identical K-Ar ages of 1385 ± 27 Ma and 1373 ± 27 Ma, respectively. These correspond to a Mesoproterozoic-Ectasian age related to Subjotnian or Postjotnian events. ONK-PL960 yields a K-Ar age of 1225 ± 24 Ma corresponding to a Mesoproterozoic-Ectasian age. This age agrees well with the ages from Postjotnian diabase dykes in W Finland. The 2-3 % detrital K-feldspar contamination in clay fractions increases the age. Especially for the youngest sample ONK-PL87, the effect may be geologically meaningful as after the correction the age clearly indicates Caledonian events. Moreover, the age for the low K sample ONKPL901 shifts to indicate Postjotnian diabase age. (orig.)

  12. New K-Ar constraints on the onset of subsidence in the Canning Basin, Western Australia

    International Nuclear Information System (INIS)

    Shaw, R.D.; Tyler, I.M.; Griffin, T.J.; Webb, A.

    1992-01-01

    Structural mapping and reconnaissance K-Ar studies have helped to delineate and date the latest deformational stages (D4 and D5) in the King Leopold Orogen, to the north of the Canning Basin. The dates have been determined for schists selected from both contractional shear zones and from rocks metamorphosed to the lower greenschist facies during the final phase of basement deformation. These dates imply that the basement-deforming event started in the latest Precambrian to earliest Cambrian (ca 560 Ma), and that tectonism recurred in the latest Cambrian to earliest Ordovician (ca 500 Ma). The final contractional deformation is slightly older than the oldest-known sedimentary rocks in the basin (latest Tremadoc), and helps to define the time that basin subsidence started. 23 refs., 3 tabs., 2 figs

  13. Palaeomagnetism and K-Ar age of Mesozoic and Cenozoic igneous rocks from Antarctica

    International Nuclear Information System (INIS)

    Valencio, D.A.; Mendia, J.E.; Vilas, J.F.

    1979-01-01

    A new analysis of palaeomagnetic data for igneous rocks from Deception Island, 25 de Mayo Island (King George Island) and Cape Spring, are given. K-Ar age determinations indicate that most of the igneous samples from 25 de Mayo Island included in the palaeomagnetic study are of Late Mesozoic/Early Tertiary age. The significance of these palaeomagnetic-radiometric data on the hypothesis of oroclinal bending of the Antarctic Peninsula and on the apparent polar movement of Antarctica is discussed. The positions of palaeomagnetic poles for the Andean igneous complex indicate that there has not been any apparent post-Late Cretaceous/Early Tertiary oroclinal bending in the Antarctic Peninsula from 74 0 S to 62 0 S. A comparison of the positions of palaeomagnetic poles for Antarctica and Australia suggests that the direction of apparent polar movement relative to Antarctica reversed after the Miocene. (Auth.)

  14. Low-frequency stimulation in anterior nucleus of thalamus alleviates kainate-induced chronic epilepsy and modulates the hippocampal EEG rhythm.

    Science.gov (United States)

    Wang, Yi; Liang, Jiao; Xu, Cenglin; Wang, Ying; Kuang, Yifang; Xu, Zhenghao; Guo, Yi; Wang, Shuang; Gao, Feng; Chen, Zhong

    2016-02-01

    High-frequency stimulation (HFS) of the anterior nucleus of thalamus (ANT) is a new and alternative option for the treatment of intractable epilepsy. However, the responder rate is relatively low. The present study was designed to determine the effect of low-frequency stimulation (LFS) in ANT on chronic spontaneous recurrent seizures and related pathological pattern in intra-hippocampal kainate mouse model. We found that LFS (1 Hz, 100 μs, 300 μA), but not HFS (100 Hz, 100 μs, 30 μA), in bilateral ANT significantly decreased the frequency of spontaneous recurrent seizures, either non-convulsive focal seizures or tonic-clonic generalized seizures. The anti-epileptic effect persisted for one week after LFS cessation, which manifested as a long-term inhibition of the frequency of seizures with short (20-60 s) and intermediate duration (60-120 s). Meanwhile, LFS decreased the frequency of high-frequency oscillations (HFOs) and interictal spikes, two indicators of seizure severity, whereas HFS increased the HFO frequency. Furthermore, LFS decreased the power of the delta band and increased the power of the gamma band of hippocampal background EEG. In addition, LFS, but not HFS, improved the performance of chronic epileptic mice in objection-location task, novel objection recognition and freezing test. These results provide the first evidence that LFS in ANT alleviates kainate-induced chronic epilepsy and cognitive impairment, which may be related to the modulation of the hippocampal EEG rhythm. This may be of great therapeutic significance for clinical treatment of epilepsy with deep brain stimulation. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. In vitro autoradiography of ionotropic glutamate receptors in hippocampus and striatum of aged Long-Evans rats: relationship to spatial learning

    International Nuclear Information System (INIS)

    Gallagher, M.; Bizon, J.L.; Nicolle, M.M.

    1996-01-01

    Using in vitro autoradiography, we investigated [ 3 H]α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, [ 3 H]kainate and [ 3 H]N-methyl-d-aspartate binding in two forebrain regions, the hippocampus and striatum, of young (four months of age) and aged (24-25 months of age) Long-Evans rats that had previously been tested for spatial learning ability in the Morris water maze. Although there was substantial preservation of binding in the aged rats, reductions in binding were present in the aged rats that were specific to ligand and anatomical region. In the hippocampus of aged rats, [ 3 H]α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate binding in CA1 and [ 3 H]kainate binding in CA3 were reduced. In contrast, N-methyl-d-aspartate binding was not significantly different between age groups. There was evidence of sprouting in the dentate gyrus molecular layer of aged rats, indicated by changes in the topography of [ 3 H]kainate binding. Binding density was analysed with respect to patch/matrix compartmentalization in the striatum. The most striking result was a large decrease in N-methyl-d-aspartate binding in aged rats that was not limited to any dorsal/ventral or patch/matrix area of the striatum. Additionally, [ 3 H]kainate binding in striatal matrix was modestly reduced in aged rats. Of these age effects, only N-methyl-d-aspartate binding in the striatum and [ 3 H]kainate binding in the CA3 region of the hippocampus were correlated with spatial learning, with lower binding in the aged rats associated with better spatial learning ability.Age-related alterations in ionotropic glutamate receptors differ with respect to the receptor subtype and anatomical region examined. The age effects were not neccessarily indicative of cognitive decline, as only two age-related binding changes were correlated with spatial learning. Interestingly, in these instances, lower binding in the aged rats was associated with preserved spatial learning, suggesting a compensatory reduction

  16. Antagonism of ionotropic glutamate receptors attenuates chemical ischemia-induced injury in rat primary cultured myenteric ganglia.

    Directory of Open Access Journals (Sweden)

    Elisa Carpanese

    Full Text Available Alterations of the enteric glutamatergic transmission may underlay changes in the function of myenteric neurons following intestinal ischemia and reperfusion (I/R contributing to impairment of gastrointestinal motility occurring in these pathological conditions. The aim of the present study was to evaluate whether glutamate receptors of the NMDA and AMPA/kainate type are involved in myenteric neuron cell damage induced by I/R. Primary cultured rat myenteric ganglia were exposed to sodium azide and glucose deprivation (in vitro chemical ischemia. After 6 days of culture, immunoreactivity for NMDA, AMPA and kainate receptors subunits, GluN(1 and GluA(1-3, GluK(1-3 respectively, was found in myenteric neurons. In myenteric cultured ganglia, in normal metabolic conditions, -AP5, an NMDA antagonist, decreased myenteric neuron number and viability, determined by calcein AM/ethidium homodimer-1 assay, and increased reactive oxygen species (ROS levels, measured with hydroxyphenyl fluorescein. CNQX, an AMPA/kainate antagonist exerted an opposite action on the same parameters. The total number and viability of myenteric neurons significantly decreased after I/R. In these conditions, the number of neurons staining for GluN1 and GluA(1-3 subunits remained unchanged, while, the number of GluK(1-3-immunopositive neurons increased. After I/R, -AP5 and CNQX, concentration-dependently increased myenteric neuron number and significantly increased the number of living neurons. Both -AP5 and CNQX (100-500 µM decreased I/R-induced increase of ROS levels in myenteric ganglia. On the whole, the present data provide evidence that, under normal metabolic conditions, the enteric glutamatergic system exerts a dualistic effect on cultured myenteric ganglia, either by improving or reducing neuron survival via NMDA or AMPA/kainate receptor activation, respectively. However, blockade of both receptor pathways may exert a protective role on myenteric neurons following and I

  17. Biochemical characterization of an autoradiographic method for studying excitatory amino acid receptors using L-[3H]glutamate

    International Nuclear Information System (INIS)

    Cincotta, M.; Summers, R.J.; Beart, P.M.

    1989-01-01

    A method was developed for radiolabeling excitatory amino acid receptors of rat brain with L-[ 3 H]glutamate. Effective labeling of glutamate receptors in slide-mounted 10-microns sections was obtained using a low incubation volume (0.15 ml) and rapid washing: a procedure where high ligand concentrations were achieved with minimal waste. Saturation experiments using [ 3 H]glutamate revealed a single binding site of micromolar affinity. The Bmax was trebled in the presence of Ca2+ (2.5 mM) and Cl- (20 mM) with no change in the Kd. Binding was rapid, saturable, stereospecific, and sensitive to glutamate receptor agonists. The proportions of [ 3 H]glutamate binding sensitive to N-methyl-D-aspartate (NMDA), kainate, and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) were 34, 54, and 51%, respectively. NMDA inhibited binding at a distinct subset of L-[ 3 H]glutamate sites, whereas AMPA and kainate competed for some common sites. Labeling of sections with L-[ 3 H]glutamate in the presence of the selective agonists allowed autoradiographic visualization of glutamate receptor subtypes in brain tissue

  18. Volume Measurements of Laser-generated Pits for In Situ Geochronology using KArLE (Potassium-Argon Laser Experiment)

    Science.gov (United States)

    French, R. A.; Cohen, B. A.; Miller, J. S.

    2014-01-01

    The Potassium-Argon Laser Experiment( KArLE), is composed of two main instruments: a spectrometer as part of the Laser-Induced Breakdown Spectroscopy (LIBS) method and a Mass Spectrometer (MS). The LIBS laser ablates a sample and creates a plasma cloud, generating a pit in the sample. The LIBS plasma is measured for K abundance in weight percent and the released gas is measured using the MS, which calculates Ar abundance in mols. To relate the K and Ar measurements, total mass of the ablated sample is needed but can be difficult to directly measure. Instead, density and volume are used to calculate mass, where density is calculated based on the elemental composition of the rock (from the emission spectrum) and volume is determined by pit morphology. This study aims to reduce the uncertainty for KArLE by analyzing pit volume relationships in several analog materials and comparing methods of pit volume measurements and their associated uncertainties.

  19. New K-Ar ages of the Martel Inlet Group, king George Island, South Shetland Islands, Antarctica

    International Nuclear Information System (INIS)

    Soliani Junior, E.; Kawashita, K.

    1986-01-01

    This paper presents twelve new K-Ar whole rocks ages of the Martel Inlet Group that crops out in the Keller Peninsula region, in the Admiralty Bay, King George Island. That lithostratigraphic unit has been considered the oldest one know in the area and it is the result of several volcanic and volcanoclastic episodes occurred probably during the Upper Jurassic. As the group is mainly represented by lithologies that show low-grade metamorphic changes and metasomatic evidences, as well as other alteration processes, it has been difficult to obtain that expected age, specially using the K-Ar method. A significant number of time values concentrated between 40 and 50 Ma, independently of the unit's position in the strategraphic context, could be suggesting an important tectono-thermal event that affected the area setting the isotopic results by re-heating and/or by chemical processes. (author) [pt

  20. U-Pb and K-Ar isotopic dating of Sinec (Rimavica) granites (Kohut zone of veporides)

    International Nuclear Information System (INIS)

    Bibikova, E.V.; Grachema, T.V.; Makarov, V.A.

    1988-01-01

    New results of radiometric dating of Sinec (Rimavica) granites by U-Pb and K-Ar method are presented. The K-Ar method (muscovite and biotite) gives the age of 94 m.y., which can be interpreted by tectonics. The U-Pb dating of zircons gave a concordant age of 350±5 m.y., which is a more reliable age than the one obtained from the same samples by Rb-Sr isochrone. The increased age of the Sinec (Rimavica) granites determined by the Sb-Sr method could be caused by the supply of radiogenic Sr from the surrounding older metamorphic rocks to the granites during retrograde metamorphism synchronous with granite autometasomatism. (author). 3 figs., 2 tabs., 15 refs

  1. K-Ar ages of alkaline rock from Southern Brazil and Eastern Paraguay: compilation and adaptation of new decay constants

    International Nuclear Information System (INIS)

    Sonoki, I.K.; Garda, G.M.

    1990-01-01

    A compilation of 295 geochronological data of 52 alkaline occurrences from Southern Brazil and Eastern Paraguay is presented. These data, mostly available in previous publications, were recalculated, using the new constants recommended by STEIGER and JAEGER (1977) for the K-Ar method. The estimated analytical error of the age determined using experimental parameters is also indicated (COX and DALRYMPLE, 1967). This paper aims, specifically, at making ages published prior to 1977 compatible with recent data, allowing, for example, comparisons between ages obtained from a single alkaline massif or from neighbouring massifs. By calculating K-Ar ages using the constants recommended by STEIGER and JAEGER (op. cit.), there occurs an increase of 2.1 to 2.4% in the value of the age calculated with the previous constants. (author) [pt

  2. K-Ar age of molybdenum mineralization in the east-central Kitakami Mountains, northern Honshu, Japan

    International Nuclear Information System (INIS)

    Ishihara, Shunso; Shibata, Ken; Uchiumi, Shigeru

    1989-01-01

    Three K-Ar ages were determined on rocks and minerals from the mineralized areas in the east-central part of the Kitakami Cretaceous granitic terrain, where a Paleogene mineralization age was reported recently on molybdenite by the Re-Os method. The present result showed an early Cretaceous age of 114±4 Ma for the same molybdenite deposit. A rather large discrepancy was found between the Re-Os ages for molybdenite and the K-Ar and Rb-Sr ages for silicate minerals from the same ore deposits of Mesozoic-Cenozoic ages in the Circum-Pacific region, indicating that the Re-Os method needs further examination. (author)

  3. Loss of function of Saccharomyces cerevisiae kinesin-related CIN8 and KIP1 is suppressed by KAR3 motor domain mutations.

    Science.gov (United States)

    Hoyt, M A; He, L; Totis, L; Saunders, W S

    1993-09-01

    The kinesin-related products of the CIN8 and KIP1 genes of Saccharomyces cerevisiae redundantly perform an essential function in mitosis. The action of either gene-product is required for an outwardly directed force that acts upon the spindle poles. We have selected mutations that suppress the temperature-sensitivity of a cin8-temperature-sensitive kip1-delta strain. The extragenic suppressors analyzed were all found to be alleles of the KAR3 gene. KAR3 encodes a distinct kinesin-related protein whose action antagonizes Cin8p/Kip1p function. All seven alleles analyzed were altered within the region of KAR3 that encodes the putative force-generating (or "motor") domain. These mutations also suppressed the inviability associated with the cin8-delta kip1-delta genotype, a property not shared by a deletion of KAR3. Other properties of the suppressing alleles revealed that they were not null for function. Six of the seven were unaffected for the essential karyogamy and meiosis properties of KAR3 and the seventh was dominant for the suppressing trait. Our findings suggest that despite an antagonistic relationship between Cin8p/Kip1p and Kar3p, aspects of their mitotic roles may be similar.

  4. Kars ilinde örgün eğitimin gelişimi ve mevcut durumu

    OpenAIRE

    DEMİR, MUCİP

    2016-01-01

    Doğu Anadolu Bölgesinin Kars Erzurum bölümünde yer alan Kars İli ortalama irtifası 2000 metre civarında olan ve birçok yeri volkanik materyallerle örtülü Kars Platosu üzerinde bulunmaktadır. Mevcut topografik koşulların etkisiyle sert karasal iklimin görüldüğü ilde başta nüfus olmak üzere diğer beşeri faaliyetler bu coğrafik faktörlerin yoğun etkisiyle şekillenmektedir. İlde halen 300.000 civarında bulunan nüfus il dışına doğru meydana gelen göçlerle azalış eğilimi göstermektedir. 373 ilko...

  5. VALUASI EKONOMI BIODIVERSITY KARS: STUDI KASUS VALUASI EKONOMI KAWASAN KARS MAROS, SULAWESI SELATAN (Economic Valuation of Karst Biodiversity: A Case Study of Karst Region in Maros, South Sulawesi, Indonesia

    Directory of Open Access Journals (Sweden)

    Gustami Gustami

    2002-07-01

    Full Text Available ABSTRAK Studi ini bertujuan untuk menghitung nilai ekonomi total dari kawasan kars Maros Sulawesi Selatan. Studi berlokasi di Taman Wisata Alam bantimurung, Cagar Alam Karaenta, dan Taman Wisata Alam Gua Pattunang. Kegiatan ini merupakan kerjasama Kementerian Lingkungan Hidup dan Collaborative Environmental Project in Indonesia (CEPI dengan melibatkan Staf Bapedal Regional III Makassar, Pemda Maros, Universitas Muhammadiyah dan Universitas Hasanuddin Ujung Pandang. Pendekatan biaya perjalanan adalah yang pertama dikaji untuk menghitung nilai guna langsung dari kegiatan rekreasi. Penghitungan nilai tidak langsung keberadaan kawasan kars beserta hutannya yang didasarkan pada nilai dari fungsinya sebagai sumber air dan pencegah terjadinya banjir dan longsor. Nilai preservasi kawasan kars yang dinilai dengan menghitung keinginan membayar pengunjung untuk konservasi kupu-kupu dan kumbang,perbaikan lingkungan terutama yang berkaitan dengan kebersihan, keindahan dan kesejukan dengan jumlah kunjungan pertahun. Berdasarkan hasil analisis, nilai ekonomi total yang terdiri dari nilai guna langsung, nilai guna tidak langsung serta nilai bukan guna (non use value yang berupa nilai preservasi adalah Rp. 639,556,607,830,-. Walaupun kenyataannya masih banyak nilai ekonomi lain yang belum dikaji, namun studi ini telah mengungkapkan sebagian nilai ekonomi kawasan kars yang dimanfaatkan oleh masyarakat sekitar ataupun masyarakat di luar yang mengunjungi kawasan ini untuk menikmati fenomena “kars tropika klasik” Maros.   ABSTRACT The objective of this study is to assess total economic values of karst region in Maros, South Sulawesi, spesifically at Taman wisata alam Bantimurung, Cagar alam Karaenta, and Taman Wisata Alam Gua Pattunuang. This activity was a joint project between the Ministry of Environmental Republic of Indonesia and the Collaborative Environmental Project in Indonesia (CEPI involving staff of BAPEDAL Regional III, Makassar, local government of

  6. Profiling neurotransmitter receptor expression in the Ambystoma mexicanum brain.

    Science.gov (United States)

    Reyes-Ruiz, Jorge Mauricio; Limon, Agenor; Korn, Matthew J; Nakamura, Paul A; Shirkey, Nicole J; Wong, Jamie K; Miledi, Ricardo

    2013-03-22

    Ability to regenerate limbs and central nervous system (CNS) is unique to few vertebrates, most notably the axolotl (Ambystoma sp.). However, despite the fact the neurotransmitter receptors are involved in axonal regeneration, little is known regarding its expression profile. In this project, RT-PCR and qPCR were performed to gain insight into the neurotransmitter receptors present in Ambystoma. Its functional ability was studied by expressing axolotl receptors in Xenopus laevis oocytes by either injection of mRNA or by direct microtransplantation of brain membranes. Oocytes injected with axolotl mRNA expressed ionotropic receptors activated by GABA, aspartate+glycine and kainate, as well as metabotropic receptors activated by acetylcholine and glutamate. Interestingly, we did not see responses following the application of serotonin. Membranes from the axolotl brain were efficiently microtransplanted into Xenopus oocytes and two types of native GABA receptors that differed in the temporal course of their responses and affinities to GABA were observed. Results of this study are necessary for further characterization of axolotl neurotransmitter receptors and may be useful for guiding experiments aimed at understanding activity-dependant limb and CNS regeneration. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  7. K-Ar dating on acidic rocks from the Western Aizu District, Fukushima Prefecture

    International Nuclear Information System (INIS)

    Shimada, Ikuro; Ueda, Yoshio

    1979-01-01

    K-Ar age determinations were carried out on twelve samples of various acidic rocks (six volcanic rocks, two pyroclastics and four granitic rocks) which were obtained from the western part of Aizu district. The district studied is one of the important acidic petrographic provinces in the Green tuff region of Northeast Japan, and is widely covered by the acidic volcanic rocks and pyroclastics of Neogene period. The ages of six volcanic rocks range from 8 to 23 m.y., and they are generally correlated to the stratigraphic units of the Neogene in Northeast Japan. Dating results on four granitic rocks from the Tagokura granitic body showed the age range of 39 to 65 m.y., corresponding to the Late Cretaceous to Eocene. A sample of dacitic welded tuff from the Miyako River area gave an age of 44 m.y. It is pointed out that the welded tuff may be correlated to the Late Cretaceous to Paleogene acidic igneous rocks such as Nohi rhyolites, Asahi rhyolites, Tagawa acidic rocks and others, on the basis of the age and lithofacies of the rock. However, further geological and geochronological data are necessary to settle the problem. (author)

  8. The K-Ar ages and their stratigraphic interpretation of the Cheju Island volcanics, Korea

    International Nuclear Information System (INIS)

    Tamanyu, Shiroh

    1990-01-01

    K-Ar datings were performed on the 5 volcanic rock samples of the Cheju Island Korea. The results of these datings are as follows. Hallasan trachyte; 0.07±0.01 Ma, Paeknoktam Hawaiite; 0.47±0.07 Ma, Hallasan Hawaiite; 0.52±0.03 Ma, Sogwip'o Hawaiite; 0.55±0.04 Ma, P'yosonri Alkali Basalt; 0.31±0.04 Ma. Among them, only Paeknoktam Hawaiite seems to be grown older by the excess Argon. But, all other ages can be interpreted respectively as the essential ages of their eruptions. Based on these newly obtained age data and previously reported age data, the volcanism of this island can be roughly divided into three stages as follows. I stage; early Pleistocene basic-intermediate volcanism. II stage; middle Pleistocene basic volcanism. III stage; late Pleistocene-Holocene basic-intermediate volcanism. And also, the age of Sogwip'o Formation which is famous of bearing the index molluscan fossil; Turritella saishuensis Yokoyama, must be correlated to early Pleistocene. (author)

  9. K-Ar geochronology and palaeomagnetism of volcanic rocks in the lesser Antilles island arc

    International Nuclear Information System (INIS)

    Briden, J.C.; Rex, D.C.; Faller, A.M.; Tomblin, J.F.

    1979-01-01

    K-Ar age determinations on rocks and minerals from 95 locations in the Lesser Antilles. An age range of 38 - 10 million years was found for the outer arc (Limestone Caribbees) but less than 7.7 million years in the inner arc (Volcanic Caribbees). From Martinique southwards the two arcs are superimposed. These age ranges fit between discontinuities in sea floor spreading in the North Atlantic at about 38 and 9 million years and a causal connection between spreading change and relocation of arc volcanicity is suggested. Paleomagnetic directions at 108 localities in 10 islands fall into normal and reversed groups with 6 sites intermediate and 5 indeterminate. The mean dipole axis is within 2% of the present rotation axis. The data generally agrees with the established geomagnetic polarity time scale but there is some suggestion of a normal polarity event at about 1.18 million years. The paleomagnetic data suggest that in the past 10 million years the Lesser Antilles have not changed their latitude or geographical orientation and the geomagnetic field has averaged that of a central axial dipole. (author)

  10. K-Ar ages of the Hiruzen volcano group and the Daisen volcano

    International Nuclear Information System (INIS)

    Tsukui, Masashi; Nishido, Hirotsugu; Nagao, Keisuke.

    1985-01-01

    Seventeen volcanic rocks of the Hiruzen volcano group and the Daisen volcano, in southwest Japan, were dated by the K-Ar method to clarify the age of volcanic activity in this region and the evolution of these composite volcanoes. The eruption ages of the Hiruzen volcano group were revealed to be about 0.9 Ma to 0.5 Ma, those of the Daisen volcano to be about 1 Ma to very recent. These results are consistent with geological and paleomagnetic data of previous workers. Effusion of lavas in the area was especially vigorous at 0.5+-0.1 Ma. It was generally considered that the Hiruzen volcano group had erupted during latest Pliocene to early Quaternary and it is older than the Daisen volcano, mainly from their topographic features. However, their overlapping eruption ages and petrographical similarities of the lavas of the Hiruzen volcano group and the Daisen volcano suggest that they may be included in the Daisen volcano in a broad sense. The aphyric andesite, whose eruption age had been correlated to Wakurayama andesite (6.34+-0.19 Ma) in Matsue city and thought to be the basement of the Daisen volcano, was dated to be 0.46+-0.04 Ma. It indicates that petrographically similar aphyric andesite erupted sporadically at different time and space in the San'in district. (author)

  11. K-Ar chronological study of the quaternary volcanic activity in Shin-etsu Highland

    International Nuclear Information System (INIS)

    Kaneko, Takayuki; Shimizu, Satoshi; Itaya, Tetsumaru.

    1989-01-01

    In order to clarify the temporal and spatial patterns in arc volcanism, 55 K-Ar ages of volcanic rocks from 17 volcanoes in Shin-etsu Highland, central Japan were determined. In addition, life spans, volume of erupted materials and eruption rates of each volcano were estimated. Graphical analysis demonstrates that volume of ejecta varies proportionately with both life span and eruption rate, and that there is no significant correlation between eruption rate and distance from the volcanic front. The life span of each volcano in this Highland is less than 0.6 m.y. In the central Shiga and southern Asama area, the volcanism started at 1 Ma and is still active. However the former had a peak in the activity at around 0.5 Ma, while the latter is apparently most intense at present. Northern Kenashi area has the volcanism without peak in 1.7 - 0.2 Ma, though the activity within a volcanic cluster or chain in central Japan lasts generally for 1 m.y. or less with a peak. (author)

  12. Acute alterations of somatodendritic action potential dynamics in hippocampal CA1 pyramidal cells after kainate-induced status epilepticus in mice.

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    Daniel Minge

    Full Text Available Pathophysiological remodeling processes at an early stage of an acquired epilepsy are critical but not well understood. Therefore, we examined acute changes in action potential (AP dynamics immediately following status epilepticus (SE in mice. SE was induced by intraperitoneal (i.p. injection of kainate, and behavioral manifestation of SE was monitored for 3-4 h. After this time interval CA1 pyramidal cells were studied ex vivo with whole-cell current-clamp and Ca(2+ imaging techniques in a hippocampal slice preparation. Following acute SE both resting potential and firing threshold were modestly depolarized (2-5 mV. No changes were seen in input resistance or membrane time constant, but AP latency was prolonged and AP upstroke velocity reduced following acute SE. All cells showed an increase in AP halfwidth and regular (rather than burst firing, and in a fraction of cells the notch, typically preceding spike afterdepolarization (ADP, was absent following acute SE. Notably, the typical attenuation of backpropagating action potential (b-AP-induced Ca(2+ signals along the apical dendrite was strengthened following acute SE. The effects of acute SE on the retrograde spread of excitation were mimicked by applying the Kv4 current potentiating drug NS5806. Our data unveil a reduced somatodendritic excitability in hippocampal CA1 pyramidal cells immediately after acute SE with a possible involvement of both Na(+ and K(+ current components.

  13. Cyto- and receptor architecture of area 32 in human and macaque brains.

    Science.gov (United States)

    Palomero-Gallagher, Nicola; Zilles, Karl; Schleicher, Axel; Vogt, Brent A

    2013-10-01

    Human area 32 plays crucial roles in emotion and memory consolidation. It has subgenual (s32), pregenual (p32), dorsal, and midcingulate components. We seek to determine whether macaque area 32 has subgenual and pregenual subdivisions and the extent to which they are comparable to those in humans by means of NeuN immunohistochemistry and multireceptor analysis of laminar profiles. The macaque has areas s32 and p32. In s32, layer IIIa/b neurons are larger than those of layer IIIc. This relationship is reversed in p32. Layer Va is thicker and Vb thinner in s32. Area p32 contains higher kainate, benzodiazepine (BZ), and serotonin (5-HT)1A but lower N-methyl-D-aspartate (NMDA) and α2 receptor densities. Most differences were found in layers I, II, and VI. Together, these differences support the dual nature of macaque area 32. Comparative analysis of human and macaque s32 and p32 supports equivalences in cyto- and receptor architecture. Although there are differences in mean areal receptor densities, there are considerable similarities at the layer level. Laminar receptor distribution patterns in each area are comparable in the two species in layers III-Va for kainate, NMDA, γ-aminobutyric acid (GABA)B , BZ, and 5-HT1A receptors. Multivariate statistical analysis of laminar receptor densities revealed that human s32 is more similar to macaque s32 and p32 than to human p32. Thus, macaque 32 is more complex than hitherto known. Our data suggest a homologous neural architecture in anterior cingulate s32 and p32 in human and macaque brains. © 2013 Wiley Periodicals, Inc.

  14. Effect of lanthanum on rooting of in vitro regenerated shoots of Saussurea involucrata Kar. et Kir.

    Science.gov (United States)

    Guo, Bin; Xu, Ling-Ling; Guan, Zhen-Jun; Wei, Ya-Hui

    2012-06-01

    In present study, the effect of lanthanum (La) on the rooting of regenerated shoots of Saussurea involucrata Kar. et Kir was analyzed. Rooting occurred from regenerated shoots inoculated on a medium supplemented with La, the plant rooting hormone indole-3-acetic acid (IAA), or both La and IAA together. The highest rooting efficiency (96%), root number/shoot (8.5), and root length (63 mm) were recorded in shoots cultured on medium containing 2.5 μM IAA combined with 100 μM La(3+). In order to elucidate the mechanism of rooting enhancement by La, we examined dynamic changes in antioxidant enzyme activities in plant tissue over time in culture. We found that the activities of peroxidase (POX) and superoxide dismutase (SOD) were significantly higher in plant tissue cultured in IAA plus La than in La or IAA alone. At the same time, the highest H(2)O(2) content was detected in plant tissue in the presence of 2.5 μM IAA plus 100 μM La(3+). In light of these data and previous results, we speculate that La enhanced IAA-induced rooting by acting as a mild abiotic stress to stimulate POX and SOD activities in plant cells. Then, IAA reacted with oxygen and POX to form the ternary complex enzyme-IAA-O(2) that dissociated into IAA radicals and O(2)(-). Subsequently, IAA-induced O(2)(-) readily converted to hydroxyl radical (HO·) via SOD-catalyzed dismutation. Finally, cell wall loosening and cell elongation occurred as a consequence of HO-dependent scission of wall components, leading to root growth. The treatment of IAA combined with La resulted in the highest plantlet survival (80%) compared to single treatments with IAA or La alone. These data suggest that rare earth elements enhance root morphogenesis and the growth of S. involucrata.

  15. K-Ar ages of Early Miocene arc-type volcanoes in northern New Zealand

    International Nuclear Information System (INIS)

    Hayward, B.W.; Black, P.M.; Smith, I.E.M.; Ballance, P.F.; Itaya, T.; Doi, M.; Takagi, M.; Bergman, S.; Adams, C.J.; Herzer, R.H.; Robertson, D.J.

    2001-01-01

    Understanding the temporal and spatial development of the Early Miocene Northland Volcanic Arc is critical to interpreting the patterns of volcanic activity in northern New Zealand through the Late Cenozoic. The northwesterly trending arc is considered to have developed above a southwest-dipping subduction system. The distribution of its constituent eruptive centres is described in terms of an eastern belt that extends along the eastern side of Northland and a complementary broad western belt which includes subaerial and submarine volcanic edifices. Critical examination of all 216 K-Ar ages available, including 180 previously unpublished ages, and their assessment against tectonic, lithostratigraphic, seismic stratigraphic, and biostratigraphic constraints, leads us to deduce a detailed chronology of periods of activity for the various Early (and Middle) Miocene arc-type volcanic complexes and centres of northern New Zealand: Waipoua Shield Volcano Complex (19-18 Ma, Altonian); Kaipara Volcanic Complex (23-16 Ma, Waitakian-Altonian); Manukau Volcanic Complex (c. 23-15.5 Ma, Waitakian-Clifdenian); North Cape Volcanic Centre (23-18 Ma, Waitakian-Altonian); Whangaroa Volcanic Complex (22.5-17.5 Ma, Waitakian-Altonian); Taurikura Volcanic Complex (22-15.5 Ma, Otaian-Clifdenian); Parahaki Dacites (22.5-18 Ma, Waitakian-Altonian); Kuaotunu Volcanic Complex (18.5-11 Ma, Altonian-Waiauan). In general, volcanic activity does not show geographic migration with time, and the western (25-15.5 Ma) and eastern (23-11 Ma) belts appear to have developed concurrently. (author). 123 refs., 9 figs., 1 tab

  16. TRADITION OF KARS MINSTREL ACCORDING TO THE TYPE OF FOLK POET IN DEDE KORKUT STORIES DEDE KORKUT HİKÂYELERİNDEKİ OZAN TİPİ BAĞLAMINDA KARS ÂŞIKLIK GELENEĞİ

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    Cengiz GÖKŞEN

    2011-12-01

    Full Text Available The Dede Korkut stories are one of the most important commonvalues of Turkish World. Although this work had been written thehundreds of years later that the Turks accepted Islam religion, it hasmany elements of Turkish culture that belongs to pre-islamic period. Thecustom of being a poet, which is a type of musician, is one of theTurkish culture of pre-islamic age. The poets were not only musicianswho had ability of music, but also they have the ability of a religiousperson, a doctor or a witch. After a while, by the effects of Islamicculture, these poets had left their places to the minstrels(=Aşık. Kars andits neighbourhood is one of the place that the custom of minstrel hasperformed mostly. There has been many common elements between thetype of poets in the Dede Korkut Stories and in the living tradition ofminstrel of Kars. In this study, the similarities between the Dede KorkutStories and Kars minstrel tadition, and the reason of these had been triedto be defineted. Dede Korkut Hikâyeleri Türk Dünyasının en önemli ortakdeğerlerinden biridir. Bu eser, Türklerin İslam dinini kabul etmesindenyüzlerce yıl sonra yazıya geçirilmiş olmasına rağmen, İslamiyet öncesiTürk kültür hayatına ait birçok unsur taşımaktadır. İslamiyet öncesiTürk kültürünün müzisyen sanatçı tipi olan ozan’lık geleneği bunlardanbiridir. Müzisyenlik yanında, din adamlığı, büyücülük, hekimlik gibi bilgive becerilere de sahip olan ozanlar İslamiyet’in de etkisiyle bir süre sonrayerlerini âşıklara bırakmışlardır Âşıklık geleneğinin ülkemizde en canlıyaşadığı yerlerden biri Kars ve çevresidir. Yaşayan Kars âşıklık geleneğiiçinde Dede Korkut Hikâyelerindeki ozan tipi ve ozanlık geleneğiyle ortakbirçok unsur bulunmaktadır. Bu çalışmada Dede Korkut Hikâyelerindekiozanlık geleneğiyle Kars âşıklık geleneğindeki benzerlikler ve bunlarınsebepleri tespit edilmeye çalışılmıştır.

  17. Estudio computacional de las relaciones evolutivas de los receptores ionotrópicos NMDA, AMPA y kainato en cuatro especies de primates

    Directory of Open Access Journals (Sweden)

    Francy Johanna Moreno-Pedraza

    2010-12-01

    Full Text Available Computational study of the evolutionary relationships of the ionotropic receptors NMDA, AMPA and kainate in four species ofprimates. Objective. To identify the influence of changes on the secondary structure and evolutionary relationship of NMDA, AMPA andkainate receptors in Homo sapiens, Pan troglodytes, Pongo pygmaeus and Macaca mulatta. Materials and methods. We identified 91sequences for NMDA, AMPA and kainate receptors and analyzed with software for predicting secondary structure, phosphorylation sites,multiple alignments, selection of protein evolution models and phylogenetic prediction. Results. We found that subunits GLUR5, NR2A,NR2C and NR3A showed structural changes in the C-terminal region and formation or loss of phosphorylation sites in this zone.Additionally the phylogenetic prediction suggests that the NMDA NR2 subunits are the closest to the ancestral node that gives rise to theother subunits. Conclusions. Changes in structure and phosphorylation sites in GLUR5, NR2A, NR2C and NR3A subunits suggestvariations in the interaction of the C-terminal region with kinase proteins and with proteins with PDZ domains, which could affect thetrafficking and anchoring of the subunits. On the other hand, the phylogenetic prediction suggests that the changes that occurred in the NR2subunits gave rise to the other subunits of glutamate ionotropic receptors, primarily because the NMDA and particularly the NR2D subunitsare the most closely related to the ancestral node that possibly gave rise to the iGluRs.

  18. The Plio-Quaternary Volcanic Evolution of Gran Canaria Based on new Unspiked K-Ar ages and Magnetostratigraphy

    Science.gov (United States)

    Guillou, H.; Carracedo, J.; Perez Torrado, F.

    2003-12-01

    The combined use of radioisotopic dating, magnetostratigraphy and field geology is a powerful tool to provide reliable chronological frameworks of volcanic edifices. This approach has been used to investigate the last two stages of the volcanic evolution of Gran Canaria. Fifty samples were dated using the unspiked K-Ar method and had their magnetic polarity measured both in the field and in laboratory. Ages were compared to their stratigraphic positions and magnetic polarities before accepting their validity. The unspiked K-Ar chronology constrains the timing of lateral collapses, eruption rates and the contemporaneity of different volcano-magmatic stages at Gran Canaria. Our new data set modifies significantly the previous chronological framework of Gran Canaria, especially between 4 and 2.8 Ma. Based on these new ages, we can bracket the age of the multiple lateral collapses of the Roque Nublo stratovolcano flanks between 3.5 and 3.1 Ma .This time interval corresponds to a main period of volcanic quiescence. Calculated eruptive rates during the stratovolcano edification are about 0.1 km3/kyr which is significantly lower than the published estimates. The dating also reveals that the two main last stages are not separated by a major time gap, but that the early stages of the rift forming eruption and the vanishing activity of the Roque Nublo strato-volcano were contemporaneous for at least 600 kyrs. These results support that our combined approach provides a rapid first-pass and reliable geochronology. Nevertheless, this chronology can be amplified and made more precise where necessary through detailed Ar-Ar incremental-heating methods. Samples which should be investigated using this method are the oldest and youngest K-Ar dated flows of each volcanic stage, and samples from stratigraphic sections that hold potential to study the behaviour of the earth's magnetic field during reversals (Gauss-Gilbert transition, Olduvai and Reunion events).

  19. K/Ar hornblende ages from the higher Himalaya: implications for India-Asia collision and Himalayan metamorphosis

    International Nuclear Information System (INIS)

    Sorkhabi, R.B.; Stump, A.K.; Jain, A.K.; Manickavasagam, R.M.; Nishimura Susumu

    1993-01-01

    Two amphibolite samples from the Higher Himalayan Crystalline (HHC) belt from the Suru Valley, Zanskar, have yielded Eocene K/Ar hornblende cooling ages between 40 and 45 Ma, thus indicating much older peak metamorphic conditions in northern parts of the Indian Plate. These ages are in conformity with almost identical ages from metamorphic complexes across the Nanga Parbat syntaxis in Pakistan and reveal a 65 to 70-Ma collision phase of the Indian indentor in the NW-Himalaya. (author). 21 refs., 2 figs

  20. New K-Ar ages of volcanic rocks and associated mineralization in Canada Honda district, San Luis, Argentina

    International Nuclear Information System (INIS)

    Urbina, N.E.; Oggier, F.P

    2001-01-01

    New K-Ar ages in the Late Tertiary gold-bearing volcanic belt of the Sierras Pampeanas of San Luis, Argentina are presented. At Canada Honda district, an age of 8.49±0.2 Ma yielded by Cerro del Valle andesite indicates that the dome emplacement postdates the Diente Verde eruptive event. An even younger age of 7.3±0.2 Ma was obtained for illite from hydrothermal alteration at La Reynela mineralization which is hosted by Cerro del Valle andesite (au)

  1. K-Ar age for alunite-bearing rock from the Iwato gold deposit, Kagoshima Prefecture, southern Japan

    International Nuclear Information System (INIS)

    Togashi, Yukio; Shibata, Ken

    1984-01-01

    K-Ar age determination was made on a whole rock sample of the alunite-bearing silicified rock from the Iwato gold deposit, Kagoshima Prefecture, southern Japan. The sample is from one of the Nansatsu-type gold deposits, whose mineralization is characterized by the occurrence of leaching-type massive silicified rocks with gold dissemination. The result, 4.15 +- 0.78 Ma, is interpreted to be the age of the mineralization at the Iwato gold deposit. It also suggests that the Nansatsu-type deposits were formed in close association with andesitic volcanism in the early Pliocene age. (author)

  2. Properties of GluR3 receptors tagged with GFP at the amino or carboxyl terminus.

    Science.gov (United States)

    Limon, Agenor; Reyes-Ruiz, Jorge Mauricio; Eusebi, Fabrizio; Miledi, Ricardo

    2007-09-25

    Anatomical visualization of neurotransmitter receptor localization is facilitated by tagging receptors, but this process can alter their functional properties. We have evaluated the distribution and properties of WT glutamate receptor 3 (GluR3) alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (WT GluR3) and two receptors in which GFP was tagged to the amino terminus (GFP-GluR3) or to the carboxyl terminus (GluR3-GFP). Although the fluorescence in Xenopus oocytes was stronger in the vegetal hemisphere because of localization of internal structures (probable sites of production, storage or recycling of receptors), the insertion of receptors into the plasma membrane was polarized to the animal hemisphere. The fluorescence intensity of oocytes injected with GluR3-GFP RNA was approximately double that of oocytes injected with GFP-GluR3 RNA. Accordingly, GluR3-GFP oocytes generated larger kainate-induced currents than GFP-GluR3 oocytes, with similar EC(50) values. Currents elicited by glutamate, or AMPA coapplied with cyclothiazide, were also larger in GluR3-GFP oocytes. The glutamate- to kainate-current amplitude ratios differed, with GluR3-GFP being activated more efficiently by glutamate than the WT or GFP-GluR3 receptors. This pattern correlates with the slower decay of glutamate-induced currents generated by GluR3-GFP receptors. These changes were not observed when GFP was tagged to the amino terminus, and these receptors behaved like the WT. The antagonistic effects of 6-nitro-7-sulfamoylbenzo[f]quinoxaline-2,3-dione (NBQX) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) were not altered in any of the tagged receptors. We conclude that GFP is a useful and convenient tag for visualizing these proteins. However, the effects of different sites of tag insertion on receptor characteristics must be taken into account in assessing the roles played by these receptor proteins.

  3. Effect of endurance training on seizure susceptibility, behavioral changes and neuronal damage after kainate-induced status epilepticus in spontaneously hypertensive rats.

    Science.gov (United States)

    Tchekalarova, J; Shishmanova, M; Atanasova, D; Stefanova, M; Alova, L; Lazarov, N; Georgieva, K

    2015-11-02

    The therapeutic efficacy of regular physical exercises in an animal model of epilepsy and depression comorbidity has been confirmed previously. In the present study, we examined the effects of endurance training on susceptibility to kainate (KA)-induced status epilepticus (SE), behavioral changes and neuronal damage in spontaneously hypertensive rats (SHRs). Male SHRs were randomly divided into two groups. One group was exercised on a treadmill with submaximal loading for four weeks and the other group was sedentary. Immediately after the training period, SE was evoked in half of the sedentary and trained rats by KA, while the other half of the two groups received saline. Basal systolic (SP), diastolic (DP) and mean arterial pressure (MAP) of all rats were measured at the beginning and at the end of the training period. Anxiety, memory and depression-like behaviour were evaluated a month after SE. The release of 5-HT in the hippocampus was measured using a liquid scintillation method and neuronal damage was analyzed by hematoxylin and eosin staining. SP and MAP of exercised SHRs decreased in comparison with the initial values. The increased resistance of SHRs to KA-induced SE was accompanied by an elongated latent seizure-free period, improved object recognition memory and antidepressant effect after the training program. While the anticonvulsant and positive behavioral effects of endurance training were accompanied by an increase of 5-HT release in the hippocampus, it did not exert neuroprotective activity. Our results indicate that prior exercise is an effective means to attenuate KA-induced seizures and comorbid behavioral changes in a model of hypertension and epilepsy suggesting a potential influence of hippocampal 5-HT on a comorbid depression. However, this beneficial impact does not prevent the development of epilepsy and concomitant brain damage. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Southern Brasilia Belt (SE Brazil): tectonic discontinuities, K-Ar data and evolution during the Neoproterozoic Brasiliano orogeny

    International Nuclear Information System (INIS)

    Valeriano, Claudio Morrison de; Teixeira, Wilson; Simoes, Luiz Sergio Amarante; Heilbron, Monica

    2000-01-01

    This paper focuses the tectonic evolution of the southern brasilia belt, with emphasis on the Furnas segment, along the 21 deg C S parallel. The uppermost structural unit (Passos Nappe - PN) comprises a highly deformed metasedimentary succession interpreted as a fragment of the Neoproterozoic passive margin of western Sao francisco craton. An inverted metamorphic gradient ranging from greensvhits to lower granulite facies of medium to high-pressure regime characterizes the PN as relict of a subduction zone. The External Domain display a complex imbrication of basement rocks (Archean Piumhi greenstones, a turbiditic gaywacke succession and a calc-alkaline granitoid suite) with undated siliciclast low-grade metasedimentary rocks. The Sao Francisco Craton (SFC) comprises pre-1.8 Ga basement rocks covered by anchimetamorphic Neoproterozoic carbonatic shallow marine platform deposits of the Bambui group. The Brasiliano thrust stacking generated a coarse clastic influx of molassic character on the foreland zone of Sao Francisco Craton, coeval with the exhumation of the External Domain thrust sheets. New K-Ar determinations on mineral separates are presented an interpreted among previous data. The SFC basement rocks display Paleo-to Meesoproterozoic cooling ages. The allochthonous units, in contrast, display K-Ar ages within the 560-675 Ma range. Brasiliano thrust stacking is therefore interpreted to have taken place onto a cold Sao Francisco craton foreland, in a thin-skinned style, as basement rocks were not heated enough to have their-K-ar systems reset during the allochthony. (author)

  5. K-Ar geochronology of the Survey Pass, Ambler River and Eastern Baird Mountains quadrangles, southwestern Brooks Range, Alaska

    Science.gov (United States)

    Turner, Donald L.; Forbes, R.B.; Mayfield, C.F.

    1978-01-01

    We report 76 previously unpublished K-Ar mineral ages from 47 metamorphic and igneous rocks in the southwestern Brooks Range. The pattern of radiometric ages is complex, reflecting the complex geologic history of this area. Local and regional radiometric evidence suggests that the southern Brooks Range schist belt has, at least in part, undergone a late Precambrian metamorphism and that the parent sedimentary and igneous rocks for the metamorphic rocks dated as late Precambrian are at least this old (Precambrian Z). This schist terrane experienced a major thermal event in mid-Cretaceous time, causing widespread resetting of nearly all K-Ar mica ages. A series of apparent ages intermediate between late Precambrian and mid-Cretaceous are interpreted as indicating varying amounts of partial argon loss from older rocks during the Cretaceous event. The schist belt is characterized by dominant metasediments and subordinate metabasites and metafelsites. Blueschists occur within the schist belt from the Chandalar quadrangle westward to the Baird Mountains quadrangle, but geologic evidence does not support the existence of a fossil subduction zone.

  6. Molecular and serological investigation of border disease virus infection in sheep in the Kars District of Turkey

    Directory of Open Access Journals (Sweden)

    Volkan Yilmaz

    2014-01-01

    Full Text Available This study is a serological and virological examination of the border disease virus (BDV in sheep at 1–5 years of age from private small scale production units of less than 20 sheep per unit, in the Kars District of Turkey. For this purpose, blood sera from 460 sheep were tested for antibodies against BDV using a commercial enzyme-linked immunosorbent assay (ELISA. Since BDV causes persistent infection, antigen-ELISA was also performed for this agent. Seropositivity rate was detected to be 74.57%. In addition, the BDV antigen was detected in one sample of seronegative sera (0.85%. Reverse transcription polymerase chain reaction (RT-PCR technique was used to determine the presence of pestivirus nucleic acid by using 5’UTR primer pair. Pestivirus nucleic acid was found in 2 of 117 seronegative samples (1.71% by RT-PCR. The results suggest that the infection was spreading in private small scale production units. Furthermore, recommendations for the control of BDV infection are presented. This study is the first molecular and serological study to determine viroprevalence and seroprevalence of BDV infection in sheep in the Kars District of Turkey.

  7. Regulation of GABA and benzodiazepine receptors following neurotoxin-induced striatal and medial forebrain bundle lesions

    International Nuclear Information System (INIS)

    Pan, H.S.I.

    1985-01-01

    GABA, a major inhibitory transmitter, is used by many projection neurons of the striatum. To investigate the role of GABA in striatal function, the GABA receptor complex was studied after lesions of the striatum or the nigrostriatal neurons. Quantitative receptor autoradiography using thaw-mounted tissue slices was developed for the study of GABA and benzodiazepine (BDZ) receptors. With the technique established, binding to GABA and BDZ receptors after unilateral striatal kainate lesions was examined. Subsequently, changes in GABA and BDZ receptors were studied following the destruction of dopaminergic nigrostriatal cells by unilateral 6-hydroxydopamine lesion of the medial forebrain bundle. In summary, quantitative receptor autoradiography allowed the detection of GABA and BDZ receptor changes in multiple small areas in each lesioned brain. This technique made it feasible to carry out kinetic saturation, and competition studies using less than 1 mg of tissue. The data suggest that dopamine is functionally inhibitory on striatopallidal neurons but is functionally excitatory on striatoentopeduncular and striatonigral cells which in turn inhibit the thalamus. This quantitative autoradiographic technique can be generalized to study other transmitter receptors and can be combined with 2-deoxyglucose uptake studies

  8. Systemic administration of kainic acid induces selective time dependent decrease in [125I]insulin-like growth factor I, [125I]insulin-like growth factor II and [125I]insulin receptor binding sites in adult rat hippocampal formation

    International Nuclear Information System (INIS)

    Quirion, R.; Chabot, J.-G.; Dore, S.; Seto, D.; Kar, S.

    1997-01-01

    Administration of kainic acid evokes acute seizure in hippocampal pathways that results in a complex sequence of functional and structural alterations resembling human temporal lobe epilepsy. The structural alterations induced by kainic acid include selective loss of neurones in CA1-CA3 subfields and the hilar region of the dentate gyrus followed by sprouting and permanent reorganization of the synaptic connections of the mossy fibre pathways. Although the neuronal degeneration and process of reactive synaptogenesis have been extensively studied, at present little is known about means to prevent pathological conditions leading to kainate-induced cell death. In the present study, to address the role of insulin-like growth factors I and II, and insulin in neuronal survival as well as synaptic reorganization following kainate-induced seizure, the time course alterations of the corresponding receptors were evaluated. Additionally, using histological preparations, the temporal profile of neuronal degeneration and hypertrophy of resident astroglial cells were also studied. [ 125 I]Insulin-like growth factor I binding was found to be decreased transiently in almost all regions of the hippocampal formation at 12 h following treatment with kainic acid. The dentate hilar region however, exhibited protracted decreases in [ 125 I]insulin-like growth factor I receptor sites throughout (i.e. 30 days) the study. [ 125 I]Insulin-like growth factor II receptor binding sites in the hippocampal formation were found to be differentially altered following systemic administration of kainic acid. A significant decrease in [ 125 I]insulin-like growth factor II receptor sites was observed in CA1 subfield and the pyramidal cell layer of the Ammon's horn at all time points studied whereas the hilar region and the stratum radiatum did not exhibit alteration at any time. A kainate-induced decrease in [ 125 I]insulin receptor binding was noted at all time points in the molecular layer of the

  9. New K-Ar ages of altered rocks from Paramillos Sur and Norte: Interpretation of the results; Nuevas edades K-Ar de las rocas alteradas de Paramillos Sur y Norte: Interpretacion de los resultados

    Energy Technology Data Exchange (ETDEWEB)

    Koukharsky, Magdalena; Brodtkorb, Alejo [Buenos Aires Univ. (Argentina). Facultad de Ciencias Exactas y Naturales; Munizaga, Francisco [Chile Univ., Santiago (Chile). Dept. de Geologia

    1998-07-01

    The whole-rock K-Ar dates from porphyry copper prospects of Paramillos Sur (phyllic and potasic alteration zones) and Paramillos Norte (propilitic zone) are reported. Radiometric data yielded 17,8 {+-} 0,9 Ma, 15,8 {+-} 1,0 Ma and 15,2 {+-} 0,5 Ma in Paramillos Sur, and 17,3 {+-} 0,7 Ma in Paramillos Norte, which can be added to an previously reported age of 16,4 {+-} 0,3 Ma. These data are in agreement with isotopic ages from non altered or non mineralized magmatic rocks of the region. When the isotopic ages and petrographic characteristics of the dated rocks are considered, two alteration-mineralization events are suggested for Paramillos Sur prospect. However this possibility needs to be confirmed by means of future studies, in view of the reduced interval between these events when compared with the analytical errors. (author)

  10. Plio-Pleistocene basanitic and melilititic series of the Bohemian Massif: K-Ar ages, major/trace element and Sr–Nd isotopic data

    Czech Academy of Sciences Publication Activity Database

    Ulrych, Jaromír; Ackerman, Lukáš; Balogh, K.; Hegner, E.; Jelínek, E.; Pécskay, Z.; Přichystal, A.; Upton, B. G. J.; Zimák, J.; Foltýnová, R.

    2013-01-01

    Roč. 73, č. 4 (2013), s. 429-450 ISSN 0009-2819 Institutional support: RVO:67985831 Keywords : Bohemian Massif * Plio-Pleistocene * Basanite * Melilitite * K-Ar age * Magmatism * Sr–Nd isotopes Subject RIV: DD - Geochemistry Impact factor: 1.397, year: 2013

  11. Investigation into the metamorphic Nappes of the Central Scandinavian Caledonides on the basis of Rb-Sr and K-Ar age determination

    International Nuclear Information System (INIS)

    Reymer, A.P.S.

    1979-01-01

    This study concerns age determinations on several rock units of metamorphic nappes in the central Scandinavian Caledonides. Rb-Sr analyses on whole-rocks and minerals (biotite, muscovite/phengite, feldspars, garnet) were made as well as K-Ar determinations on biotite, muscovite/phengite, amphibole and feldspar. (Auth.)

  12. The use of Rb-Sr and K-Ar dating methods as a stratigraphic tool applied to sedimentary rocks and minerals

    International Nuclear Information System (INIS)

    Bonhomme, M.G.

    1982-01-01

    Rb-Sr and K-Ar methods can be used for direct numerical chronostratigraphy of sediments using the clay silicates they contain. The interpretation of the ages calculated depends on the satisfaction of the following requirements: (1) The series studied must include diagenetic clay sediments. Coarsely-detrital or slightly-metamorphic formations must be excluded. Studies in progress concerning decarbonatation may lead to the application of direct dating of sediments being extended to carbonate sediments. (2) Careful mineralogical study of the clay minerals must prove early diagenetic recrystallization or new formation. This part of the study must precede any isotopic work. (3) The isotopic study must involve the use of both Rb-Sr and K-Ar methods. The extreme sensibility of the K-Ar isotopic system to late diagenesis helps to choose between early or late diagenesis: a younger K-Ar age may generally be regarded as that of the late diagenesis, whereas the Rb-Sr age may be that of the early diagenesis. (4) The initial 87 Sr/ 86 Sr isotopic ratio is not always a reliable criterion, owing to the effects of the dilution of the radiogenic 87 Sr by the great amounts of primary Sr contained in carbonates. (5) The regularly-decreasing succession of isotopic ages must follow the stratigraphic succession. When this condition is satisfied, there is a high probability that the calculated ages are indeed those of the deposition dates. (Auth.)

  13. K/Ar dating of Neogene volcanic activity in Hungary: Experimental technique, experiences and methods of chronological studies

    International Nuclear Information System (INIS)

    Balogh, Kadosa

    1985-01-01

    Construction and essential parameters of an argon extraction line and magnetic mass spectrometer for K/Ar dating are descibed. Experiences of chronoligical studies on Miocene intermediate and acid lavas and tuffs as well as on Pliocene basalts are summarized. Great attention is paid to the ascertainment of the geological reliability of radiometric ages. Experiences concerning the frequency, character and reason of geological errors for the different rock types are reviewed and methods of sample selection used for the recognition of unreliable ages are outlined. The isochron methods are used mostly for dating Pliocene basalts. The limitations of the pure mathematical treatment of the experimental data are pointed out and geological interpretation of the isochron ages is discussed. The uncertainty of error estimation of isotopic ratio and potassium concentration measurements is emphasized. (author)

  14. European Islands, Development and the Cohesion Policy: A Case Study of Kökar, Åland Islands

    Directory of Open Access Journals (Sweden)

    Godfrey Baldacchino

    2010-05-01

    Full Text Available A European Union initiative is seeking ways of determining the development potential of Europe’s lagging regions, which include various islands. On the basis of the policy review, methodology and data collected by the ongoing EUROISLANDS project, this paper present Kökar (population: 262, the easternmost municipality of the Åland Islands, as a prototype archipelago that is seriously challenged by its size and multiple peripherality. It reviews the state of its social and transportation infrastructure, and of its human and financial capital. While the situation is serious, there are opportunities for branding, for developing associated economic activity, as well for appealing to a new wave of residents.

  15. New K-Ar ages of altered rocks from Paramillos Sur and Norte: Interpretation of the results

    International Nuclear Information System (INIS)

    Koukharsky, Magdalena; Brodtkorb, Alejo; Munizaga, Francisco

    1998-01-01

    The whole-rock K-Ar dates from porphyry copper prospects of Paramillos Sur (phyllic and potasic alteration zones) and Paramillos Norte (propilitic zone) are reported. Radiometric data yielded 17,8 ± 0,9 Ma, 15,8 ± 1,0 Ma and 15,2 ± 0,5 Ma in Paramillos Sur, and 17,3 ± 0,7 Ma in Paramillos Norte, which can be added to an previously reported age of 16,4 ± 0,3 Ma. These data are in agreement with isotopic ages from non altered or non mineralized magmatic rocks of the region. When the isotopic ages and petrographic characteristics of the dated rocks are considered, two alteration-mineralization events are suggested for Paramillos Sur prospect. However this possibility needs to be confirmed by means of future studies, in view of the reduced interval between these events when compared with the analytical errors. (author)

  16. K-AR chronology of the ultimate activity of Piton des Neiges volcano, Reunion Island, Indian Ocean

    International Nuclear Information System (INIS)

    Gillot, P.Y.; Nativel, P.; Paris-11 Univ., 91 - Orsay

    1982-01-01

    Potassium-argon measurements were made on 17 samples from the ultimate stage of activity of the Piton des Neiges volcano, which corresponds to a differentiated series with lavas varying from basalt to quartz trachyte. Samples were selected as a function of their stratographic position and their representativity of magmatic evolution. The technology used to date young volcanic rocks (Pleistocene) by K-Ar is described and discussed because of its reliability in the analysis of modern lavas and because of the agreement of the results with the available stratigraphic control. The data, together with those previously obtained by McDougall, yield ages ranging between 330.000 and 30.000 years, with two mainly effusive periods separated by a phase of instability of chiefly explosive volcanism around 190.000 to 150.000 years ago. A rough correlation between the chemical evolution of the lavas and time is established. (orig./ME)

  17. K-Ar ages of the low-grade metamorphic rocks in the Altar massif, Northwest Sonora, Mexico

    International Nuclear Information System (INIS)

    Hayama, Yoshikazu; Shibata, Ken; Takeda, Hideo.

    1984-01-01

    The K-Ar ages of low-grade regional metamorphism, granodiorite intrusion and its contact metamorphism were studied in the Altar massif of Northwest Sonora, Mexico. The results gave the ages of 55 Ma for metamorphic hornblende and 15 to 17 Ma for mica of metamorphic rocks and granodiorite. About the meaning of these discordant ages and the too young ages of 15 to 17 Ma against the previously presented data, we pointed out the following two possibilities; 1) the contact effect of the Miocene granodiorite on the regional metamorphic rocks of the Laramide phase, 2) both regional metamorphism and granodiorite intrusion took place during the Laramide phase, whereas the young ages, 15 to 17 Ma, show the time of temperature release after the low-angle thrust movement, which is well known in the hinterland of the Sevier orogenic belt in Nevada and Utah. (author)

  18. K-Ar ages, paleomagnetism, and geochemistry of the South Auckland volcanic field, North Island, New Zealand

    International Nuclear Information System (INIS)

    Briggs, R.M.; Okada, T.; Itaya, T.; Shibuya, H.; Smith, I.E.M.

    1994-01-01

    The South Auckland volcanic field is one of the Pliocene-Quaternary intraplate basaltic fields in northern North Island. It consists of at least 97 monogenetic volcanic centres covering an area of c. 300 km 2 , 38 km south of Auckland. Fifty-nine of the volcanic centres are characterised by mainly magmatic or effusive activity that constructed scoria cones and lava flows, while 38 are mainly phreatomagmatic or explosive that produced tuff rings and maars. Rock types consist of basanites, hawaiites, nepheline hawaiites, transitional basalts, and ol-tholeiitic basalts, with relatively minor amounts of nephelinites, alkali basalts, Q-tholeiitic basalts, and nepheline mugearites. Forty-three new K-Ar ages are presented, which range from 0.51 to 1.59 Ma, and show two peaks of activity at 0.6 and 1.3 Ma. Paleomagnetic determinations at 26 selected sites agree well with the paleomagnetic reversal time scale and support the K-Ar age data. Age data from each of the volcanic fields of Okete, Ngatutura, South Auckland, and Auckland, which constitute the Auckland intraplate basaltic province, show that they have developed within a time span of 0.3-1.1 Ma. After activity ceased in any particular field, a new field then developed 35-38 km to the north. These consistent time/space patterns indicate the possibility of a mantle source migrating northwards at c. 5 cm/yr. There is no correlation of rock composition with time, which is consistent with observations in the Northland intraplate province, but is not consistent with the formerly invoked rising diapir model. (author). 30 refs., 8 figs., 3 tabs

  19. Insulin receptors

    International Nuclear Information System (INIS)

    Kahn, C.R.; Harrison, L.C.

    1988-01-01

    This book contains the proceedings on insulin receptors. Part A: Methods for the study of structure and function. Topics covered include: Method for purification and labeling of insulin receptors, the insulin receptor kinase, and insulin receptors on special tissues

  20. Adeno-associated viral vector-induced overexpression of neuropeptide Y Y2 receptors in the hippocampus suppresses seizures

    DEFF Research Database (Denmark)

    Woldbye, David Paul Drucker; Ängehagen, Mikael; Gøtzsche, Casper René

    2010-01-01

    Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure...... recombinant adeno-associated viral vectors. In two temporal lobe epilepsy models, electrical kindling and kainate-induced seizures, vector-based transduction of Y2 receptor complementary DNA in the hippocampus of adult rats exerted seizure-suppressant effects. Simultaneous overexpression of Y2...... and neuropeptide Y had a more pronounced seizure-suppressant effect. These results demonstrate that overexpression of Y2 receptors (alone or in combination with neuropeptide Y) could be an alternative strategy for epilepsy treatment....

  1. Radial symmetry in a chimeric glutamate receptor pore

    Science.gov (United States)

    Wilding, Timothy J.; Lopez, Melany N.; Huettner, James E.

    2014-02-01

    Ionotropic glutamate receptors comprise two conformationally different A/C and B/D subunit pairs. Closed channels exhibit fourfold radial symmetry in the transmembrane domain (TMD) but transition to twofold dimer-of-dimers symmetry for extracellular ligand binding and N-terminal domains. Here, to evaluate symmetry in open pores we analysed interaction between the Q/R editing site near the pore loop apex and the transmembrane M3 helix of kainate receptor subunit GluK2. Chimeric subunits that combined the GluK2 TMD with extracellular segments from NMDA receptors, which are obligate heteromers, yielded channels made up of A/C and B/D subunit pairs with distinct substitutions along M3 and/or Q/R site editing status, in an otherwise identical homotetrameric TMD. Our results indicate that Q/R site interaction with M3 occurs within individual subunits and is essentially the same for both A/C and B/D subunit conformations, suggesting that fourfold pore symmetry persists in the open state.

  2. Role of glutamatergic receptors located in the nucleus raphe magnus on antinociceptive effect of morphine microinjected into the nucleus cuneiformis of rat.

    Science.gov (United States)

    Haghparast, Abbas; Soltani-Hekmat, Ava; Khani, Abbas; Komaki, Alireza

    2007-10-29

    Neurons in the nucleus cuneiformis (CnF), located just ventrolateral to the periaqueductal gray, project to medullary nucleus raphe magnus (NRM), which is a key medullary relay for descending pain modulation and is critically involved in opioid-induced analgesia. Previous studies have shown that antinociceptive response of CnF-microinjected morphine can be modulated by the specific subtypes of glutamatergic receptors within the CnF. In this study, we evaluated the role of NMDA and kainate/AMPA receptors that are widely distributed within the NRM on morphine-induced antinociception elicited from the CnF. Hundred and five male Wistar rats weighing 250-300 g were used. Morphine (10, 20 and 40 microg) and NMDA receptor antagonist, MK-801 (10 microg) or kainate/AMPA receptor antagonist, DNQX (0.5 microg) in 0.5 microl saline were stereotaxically microinjected into the CnF and NRM, respectively. The latency of tail-flick response was measured at set intervals (2, 7, 12, 17, 22, 27 min after microinjection) by using an automated tail-flick analgesiometer. The results showed that morphine microinjection into the CnF dose-dependently causes increase in tail-flick latency (TFL). MK-801 microinjected into the NRM, just 1 min before morphine injection into the CnF, significantly attenuated antinociceptive effects of morphine. On the other hand, DNQX microinjected into the NRM, significantly increased TFL after local application of morphine into the CnF. We suggest that morphine related antinociceptive effect elicited from the CnF is mediated, in part, by NMDA receptor at the level of the NRM whereas kainite/AMPA receptor has a net inhibitory influence at the same pathway.

  3. Changes in flip/flop splicing of astroglial AMPA receptors in human temporal lobe epilepsy.

    Science.gov (United States)

    Seifert, Gerald; Schröder, Wolfgang; Hinterkeuser, Stefan; Schumacher, Thekla; Schramm, Johannes; Steinhäuser, Christian

    2002-01-01

    Recent data suggested a role for glial cells in epilepsy. This study sought to identify and functionally characterize AMPA receptors expressed by astrocytes in human hippocampal tissue resected from patients with intractable temporal lobe epilepsy. Patch-clamp and fast application methods were combined to investigate astrocytes in situ and after fresh isolation from the stratum radiatum of the hippocampal CA1 subfield. Relying on presurgical and histopathologic analysis, we divided human specimens into two groups, Ammon's horn sclerosis (AHS) and lesion-associated epilepsy. Fast application of glutamate and kainate evoked receptor currents in all cells studied. Reversal-potential analysis revealed an intermediate Ca2+ permeability of the receptor channels that did not vary between the two groups of patients. However, preapplication of the AMPA receptor-specific modulator, cyclothiazide, disclosed differences in flip-flop splicing. This treatment considerably enhanced the receptor conductance, with potentiation being significantly stronger in cells from AHS specimens compared with lesion-associated cells, suggesting upregulation of AMPA receptor flip splice variants in astrocytes of the sclerotic tissue. Compelling evidence has been accumulated showing direct and rapid signaling between neurons and glial cells. Our data suggest that in AHS patients, neuronally released glutamate will lead to an enhanced and prolonged depolarization of astrocytes, which might be involved in seizure generation and spread in this particular condition of human temporal lobe epilepsy.

  4. Structural and K/Ar Illite geochronological constraints on the brittle deformation history of the Olkiluoto Region, Southwest Finland

    International Nuclear Information System (INIS)

    Viola, G.; Zwingmann, H.; Todd, A.; Raven, M.

    2011-07-01

    Sveconorwegian orogeny whereas younger extension, almost coaxial with the latter, is interpreted as the result of the late Sveconorwegian orogenic collapse at the Meso- Neoproterozoic boundary. In order to add absolute time constraints to the conceptual model of the structural evolution of the Olkiluoto region, selected fault gouge samples were collected for K/Ar dating of authigenic and synkinematic illite. The new K/Ar ages range in total from 561.3 ± 11.2 Ma (Neoproterozoic-Ediacaran) to 1451.7 ± 29.3 Ma (Mesoproterozoic-Calymmian). Structural analysis of the dated fault cores made it possible to assign tight time constraints to several of the faulting episodes, thus strengthening the structural model produced by the study. (orig.)

  5. K-Ar ages of the Nyuto-Takakura volcanic products, southern part of the Sengan geothermal area, northeast Japan

    International Nuclear Information System (INIS)

    Suto, Shigeru; Uto, Kozo; Uchiumi, Shigeru

    1990-01-01

    The K-Ar age determination of the volcanic rocks from the Nyuto-Takakura volcano group, northeast Japan, was carried out. Nyuto-Takakura volcanoes are situated in the southern part of the Sengan geothermal area. And the Young Volcanic Rocks in the area were already divided into the Early stage volcanics (erupted in Matsuyama reversed epoch or more older epoch) and the Later stage volcanics (erupted in Brunhes normal epoch) by accumulated paleomagnetic and K-Ar age data. The results in this study are as follows; Nyuto Volcano: 0.63±0.06, 0.36±0.07 Ma, Sasamoriyama Volcano: 0.09±0.07, 0.3±0.3 Ma, Marumori Lava Dome: 0.4±0.3, 0.31±0.12 Ma, Mikadoyama Lava Dome: <1 Ma, Takakurayama-Kotakakurayama volcano: 1.4±0.5, 1.0±0.4, <0.4 Ma. The determinated ages are concordant with the volcanic stratigraphy and the paleomagnetic data. Nyuto Volcano, Sasamoriyama Volcano, Marumori Lava Dome, Mikadoyama Lava Dome and upper part of the Takakurayama-Kotakakurayama Volcano are interpreted to be erupted in Brunhes normal epoch. The volcanic rocks from the lower part of the Takakurayama-Kotakakurayama volcano show normal magnetic polarity, so they are interpreted to be erupted in Jaramillo normal polarity event. The Early stage volcanics and the Later stage volcanics in the studied area are tend to be distributed in the central part and the outer part of the area, respectively. But the determinated ages in this study show that there is no simple migration of the eruption center of the volcanic rocks from the central part to the peripheral part. There is no geothermal manifestation or alteration area around the Sasamoriyama Volcano and the Marumori Lava Dome, which are the youngest volcanoes in the studied area. So it is concluded that there is no direct correlation between the eruption age of the nearest volcano and the geothermal activity. (author)

  6. K-Ar cooling age profile from Joinville massif (PR and SC, Brazil) and Dom Feliciano belt (SC, Brazil) - Tectonics entanglement

    International Nuclear Information System (INIS)

    Siga Junior, O.; Basei, M.A.S.; Kawashita, K.

    1990-01-01

    A K-Ar cooling age profile using different minerals from metamorphic rocks of the Joinville Massif and Dom Feliciano Belt is presented. Three main geochronological domains are distinguishable, from NW to SE: 1) Northern part of the Joinville Massif (NJM); 2) Southern part of the Joinville Massif (SJM) and 3) Dom Feliciano Belt (DBF). Geochronological domains 1 and 3 yielded K-Ar values in the range 800-500 Ma and 700-500 Ma, respectively, which show a clear influence of the Brasiliano Cycle. The granulite terrain comprising the SMJ exhibits ages older than 1700 Ma, indicating that this area was cool during the Late Proterozoic Brasiliano Cycle. The SJM and NJM limit is marked by a rapid Transition from Early Proterozoic ages in the SJM to Late Proterozoic ages in the NJM. On the other hand the contact between the SJM and DFB is interpreted as a thrust at a high, relatively cool crustal level. (author)

  7. Biyodizel ve Karışımlarının Kullanıldığı bir Dizel Motorda Performans ve Emisyon Analizi

    Directory of Open Access Journals (Sweden)

    Ahmet Necati ÖZSEZEN

    2009-02-01

    Full Text Available Bu çalışmada, atık palmiye yağı kökenli biyodizel ve petrol kökenli dizel yakıtı (PKDY ile karışımlarının, bir dizel motordaki performans ve emisyon karakteristikleri üç boyutlu haritalar üzerinden analiz edilmiştir. Biyodizel ve karışımlarının performans ve emisyon karakterlerini belirlemek amacıyla, motor tam yük ve değişik devir testlerine tabi tutulmuştur. Analiz sonucunda, karışımdaki biyodizel oranı arttıkça PKDY'a göre özgül yakıt tüketiminde artış olduğu, motorun döndürme momentinde ise azalma meydana geldiği tespit edilmiştir. Emisyon analizi sonucunda ise, karışımdaki biyodizel oranı ile ilişkili olarak PKDY'a kıyasla yanmamış hidrokarbon (HC, karbon monoksit (CO ve duman koyuluğu emisyonlarında iyileşmeler olduğu, bununla birlikte karbon dioksit (CO2 ve azot oksit (NOx emisyonlarının motor devrine göre kararlı bir yapı sergilemediği belirlenmiştir.

  8. Legacy K/Ar and 40Ar/39Ar geochronologic data from the Alaska-Aleutian Range batholith of south-central Alaska

    Science.gov (United States)

    Koeneman, Lisa L.; Wilson, Frederic H.

    2018-04-06

    Sample descriptions and analytical data for more than 200 K/Ar and 40Ar/39Ar analyses from rocks of the Alaska-Aleutian Range batholith of south-central Alaska are reported here. Samples were collected over a period of 20 years by Bruce R. Reed and Marvin A. Lanphere (both U.S. Geological Survey) as part of their studies of the batholith.

  9. Structural, K-Ar and 40Ar-39Ar age studies of adularia K-feldspars from the Lizard Complex, England

    International Nuclear Information System (INIS)

    Halliday, A.N.; Mitchell, J.G.

    1976-01-01

    Conventional K-Ar analyses of fifteen adularia feldspars from the Lizard Complex yield ages between 181+-2 Ma and 220+-3 Ma (with one exception from Holseer Cove yielding an age of 156+-3 Ma). The feldspars are dominantly monoclinic but most contain a minor but constant proportion of triclinic material with variable triclinicity. An inverse correlation exists between triclinicity and K-Ar age interpreted as representing argon loss related to the structural state. Extrapolation of the data to zero triclinicity indicates a true age of 210-220 Ma. 40 Ar- 39 Ar stepwise degassing analyses yield plateau ages related to the K-Ar ages and not the crystallization age. The results can be explained in terms of postcrystallization Al-Si ordering resulting in argon loss from lattice sites which under normal diffusion conditions requires a range of activation energies. The Holseer Cove sample is monoclinic and an 40 Ar- 39 Ar stepheating analysis suggests a later crystallization at 160-170 Ma. Neither primary crystallization nor spontaneous ordering through time explain the origin of the triclinic adularia. It is suggested that ordering has been induced by the passage of low-temperature alkaline solutions at a subsequent point in geological time. Argon loss by ordering could explain the low ages found using both K-Ar and 40 Ar- 39 Ar stepheating methods when applied to feldspars in general. The 210-220 Ma, and 160-170 Ma hydrothermal events affected much of southwest England and are probably related to major geotectonic movements in western Europe. (Auth.)

  10. From the immortal regulator to the wanna-be dictator: the specters of the father in Saatleri Ayarlama Enstitüsü and kar

    OpenAIRE

    Aslan, Adile

    2012-01-01

    This study brings two texts of modern Turkish literature together, Saatleri Ayarlama Enstitüsü [The Clock-Setting Institute] and Kar (Snow) in order to show their dialogue with each other through the issues of modernization/westernization, the father complex, East-West division. Close textual analysis shows that the former is a model for the latter, which Orhan Pamuk develops in accordance with the changes in narrative techniques, developments in literary movements and unfolding of events in ...

  11. [Pēdējais karš. Atmiņa un traumas kominikācija] / Eva-Clarita Pettai

    Index Scriptorium Estoniae

    Pettai, Eva-Clarita, 1971-

    2012-01-01

    Arvustus: Pēdējais karš. Atmiņa un traumas kominikācija. Hrsg. von Mārtiņš Kaprāns, Vita Zelče. Latvijas Universitāte - Sociālo zinātņu fakultāte - Sociālo un politisko pētījumu institūts (Riga 2010)

  12. Glutamate requires NMDA receptors to modulate alpha2 adrenoceptor in medulla oblongata cultured cells of newborn rats.

    Science.gov (United States)

    Marinho da Silva, Sergio; Carrettiero, Daniel C; Chadi, Débora R F

    2014-04-03

    α2 Adrenoceptors (α2-ARs) are important in regulating the central control of blood pressure in medulla oblongata. However, it is unclear how this receptor is modulated by different receptors, especially the glutamatergic. In the present study, we studied the influence of ionotropic glutamatergic receptors over the α2-ARs in cultured cells of the medulla oblongata of newborn rats. For this purpose, the protein level of the α2-ARs was assessed after administration to the cultured cells of glutamate (glu), the agonists NMDA and kainate (KA), the NMDA receptor antagonist MK801 and the KA receptor antagonist DNQX. Results indicate that the α2-AR protein levels were increased after the treatments with glu and NMDA, and the addition of MK801 to this treatment thwarted this increase. Notwithstanding the fact that KA did not alter the receptor protein level, the combined treatment of DNQX with glu prevented the α2-AR protein modulation. In conclusion, the present study suggests that ionotropic glutamatergic receptors could be related to the α2-AR protein regulation in the medulla oblongata. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Rb-Sr and K-Ar isotopic evidence for neoproterozoic (Pan-African) granulite metamorphism from the basement of Mumbai offshore basin, India

    International Nuclear Information System (INIS)

    Rathore, S.S.; Vijan, A.R.; Singh, M.P.; Misra, K.N.; Prabhu, B.N.

    2000-01-01

    Precambrian basement from well HBM-1 in the Heera oil field of Mumbai offshore basin has been dated by Rb-Sr and K-Ar methods. Five granulitic basement samples from three conventional drill cores have yielded Rb-Sr isochron age of 502±25 Ma with an initial Sr ratio of 0.70855±0.00013. This age has been interpreted as the time of granulite facies metamorphism of the basement rocks in the region. Two whole rock samples from the basement of this well have yielded mutually concordant K-Ar ages of 505±16 Ma and 507±17 Ma. The K-Ar ages are significantly similar to Rb-Sr age obtained from this well, suggesting complete isotopic reequilibration around 500 Ma ago. The time of secondary thermal heating around 500 Ma ago in the basement of Heera field coincides with the widespread neoproterozoic (Pan-African) thermo-tectonic event extending from the Arabian Peninsula and eastern Africa covering Madagascar, southern India. Sri Lanka and East Antarctica. This study widens the limit of the Pan-African zone, which hitherto was thought to be confined to the western part (presently southern part) of the Indian subcontinent, towards further east. (author)

  14. /sup 40/Ar//sup 39/Ar and K-Ar dating of altered glassy volcanic rocks: the Dabi Volcanics, P. N. G

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.A. (Australian National Univ., Canberra. Dept. of Geology); McDougall, I. (Australian National Univ., Canberra. Research School of Earth Sciences)

    1982-11-01

    K-Ar and /sup 40/Ar//sup 39/Ar ages have been determined for altered submarine tholeiitic and boninite (high-Mg andesite) lavas from the Dabi Volcanics, Cape Vogel Peninsula, Papua New Guinea. /sup 40/Ar//sup 39/Ar whole rock total fusion and plateau ages identify a Late Paleocene age for the tholeiitic lavas (58.9 +- 1.1 Ma), and also for the boninitic lavas (58.8 +- 0.8 Ma). Apparent K-Ar ages for the same samples range from 27.2 +- 0.7 to 63.9 +- 4.5 Ma, and young K-Ar ages for glassy boninites are probably due to variable radiogenic /sup 40/Ar(/sup 40/Ar*) loss. These new ages effectively reconcile previously ambiguous age data for the Dabi Volcanics, and indicate contemporaneous tholeiitic and boninitic volcanism occurring in southeast PNG during the Late Paleocene. Smectites, developed as alteration products after glass in oceanic lavas commonly do not retain /sup 39/Ar during or subsequent to irradiation, but in some cases may contain /sup 40/Ar*. The results are discussed.

  15. 40Ar/39Ar and K-Ar dating of altered glassy volcanic rocks: the Dabi Volcanics, P.N.G

    International Nuclear Information System (INIS)

    Walker, D.A.; McDougall, I.

    1982-01-01

    K-Ar and 40 Ar/ 39 Ar ages have been determined for altered submarine tholeiitic and boninite (high-Mg andesite) lavas from the Dabi Volcanics, Cape Vogel Peninsula, Papua New Guinea. 40 Ar/ 39 Ar whole rock total fusion and plateau ages identify a Late Paleocene age for the tholeiitic lavas (58.9 +- 1.1 Ma), and also for the boninitic lavas (58.8 +- 0.8 Ma). Apparent K-Ar ages for the same samples range from 27.2 +- 0.7 to 63.9 +- 4.5 Ma, and young K-Ar ages for glassy boninites are probably due to variable radiogenic 40 Ar( 40 Ar*) loss. These new ages effectively reconcile previously ambiguous age data for the Dabi Volcanics, and indicate contemporaneous tholeiitic and boninitic volcanism occurring in southeast PNG during the Late Paleocene. Smectites, developed as alteration products after glass in oceanic lavas commonly do not retain 39 Ar during or subsequent to irradiation, but in some cases may contain 40 Ar*. The results are discussed. (author)

  16. KARS İLİNDE ÖRGÜN EĞİTİMİN GELİŞİMİ VE MEVCUT DURUMU

    OpenAIRE

    DEMİR, MUCİP

    2016-01-01

    Doğu Anadolu Bölgesinin Kars Erzurum bölümünde yer alan Kars İli ortalama irtifası 2000 metre civarında olan ve birçok yeri volkanik materyallerle örtülü Kars Platosu üzerinde bulunmaktadır. Mevcut topografik koşulların etkisiyle sert karasal iklimin görüldüğü ilde başta nüfus olmak üzere diğer beşeri faaliyetler bu coğrafik faktörlerin yoğun etkisiyle şekillenmektedir. İlde halen 300.000 civarında bulunan nüfus il dışına doğru meydana gelen göçlerle azalış eğilimi göstermektedir.373 ilkokul,...

  17. Spindle pole body-anchored Kar3 drives the nucleus along microtubules from another nucleus in preparation for nuclear fusion during yeast karyogamy.

    Science.gov (United States)

    Gibeaux, Romain; Politi, Antonio Z; Nédélec, François; Antony, Claude; Knop, Michael

    2013-02-01

    Nuclear migration during yeast karyogamy, termed nuclear congression, is required to initiate nuclear fusion. Congression involves a specific regulation of the microtubule minus end-directed kinesin-14 motor Kar3 and a rearrangement of the cytoplasmic microtubule attachment sites at the spindle pole bodies (SPBs). However, how these elements interact to produce the forces necessary for nuclear migration is less clear. We used electron tomography, molecular genetics, quantitative imaging, and first principles modeling to investigate how cytoplasmic microtubules are organized during nuclear congression. We found that Kar3, with the help of its light chain, Cik1, is anchored during mating to the SPB component Spc72 that also serves as a nucleator and anchor for microtubules via their minus ends. Moreover, we show that no direct microtubule-microtubule interactions are required for nuclear migration. Instead, SPB-anchored Kar3 exerts the necessary pulling forces laterally on microtubules emanating from the SPB of the mating partner nucleus. Therefore, a twofold symmetrical application of the core principle that drives nuclear migration in higher cells is used in yeast to drive nuclei toward each other before nuclear fusion.

  18. Autecology of Astragalus arpilobus Kar. & Kir, a promised species for restoration of the winter rangelands in the northeast of Iran

    Directory of Open Access Journals (Sweden)

    M. Jankju

    2016-04-01

    Full Text Available Studying the autecology of range plants provides the basic information on their ecological requirements, cultivation methods and the interactions with the prevailing environment. Such information is necessary for a proper range management. Some ecological characteristics of Astragalus arpilobus Kar. & Kir., were studied in the winter rangelands of Northern Khorasan province. It was naturally growing in Jargalan, Bojnourd, where the altitudinal range varied 500-600 a.s.l, slope 20-100%, and the average annual rainfall 236.85 mm. Soil properties were: loamy texture, average organic matter, low fertility, pH 7.32 and EC 2.30 ds.m-1. A. aripilobus started vegetative growth at the early March, flowering during early May, seed production during June, and terminated its yearly growth at early July. The highest nutritive values and forage quality were at the beginning of growth, which was gradually decreased towards the end of growth season. Crude protein (CP, and ash were decreased whereas acid detergent fiber (ADF, natural detergent fiber (NDF, and dry matter (DM increased by the growing season. Seeds were easily established within pots; however, seed germination rate was low (24%, which by sand paper scarification was increased up to 51%. In conclusion, feasibility of seedling establishment, high nutritive value, and concurrence of plant phenology with the time of maximum need to fodder, by livestocks, propose A. arpilobus as a promising forage plant species for restoration of the winter rangelands in Northern Khorasan province.

  19. K-Ar ages of rocks from Lago Alumine, Rucachoroi and Quillen, North Patagonian Andes, Neuquen, Republica Argentina

    International Nuclear Information System (INIS)

    Latorre, Carlos O.; Vattuone, M.E; Linares, Enrique; Leal, Pablo R

    2001-01-01

    This study presents new K-Ar ages of granitic rocks from the Patagonian Batholit in the North Patagonian Andes (38 o 00'- 39 o 30' SL), from localities near Alumine lake and from Norquinco lake to Quillen valley, in the Neuquen Province, Argentine. The granitic rocks of Patagonia had been recognized as Upper Paleozoic to Middle Jurassic batholits and as Late Jurassic to Tertiary batholiths (Rapela and Pankhurst, 1992). Geochronologically, Rapela and Kay (1988) had distinguished Early Cretaceous (140 to 120 Ma) and Late Cretaceous (110 to 75 Ma ) magmatic episodes based in potassium-argon data. For the granitic rocks of the area of Paso Icalma, Moquehue and the Rahue granodiorites, Cingolani et al. (1991) presented Rb-Sr whole rock isochron ages of 70±10 Ma, 209±13 Ma and 237±37 Ma, respectively, and Varela et al. (1994), with the same method, cited an age of 285±5 Ma for the Rahue granodiorites and diorites (au)

  20. In situ dating on Mars: A new approach to the K-Ar method utilizing cosmogenic argon

    Science.gov (United States)

    Cassata, William S.

    2014-01-01

    Cosmogenic argon isotopes are produced in feldspars via nuclear reactions between cosmic rays and Ca and K atoms within the lattice. These cosmogenic isotopes can be used as proxies for K and Ca, much like nuclear reactor-derived 39Ar and 37Ar are used as proxies for K and Ca, respectively, in 40Ar/39Ar geochronology. If Ca and K are uniformly distributed, then the ratio of radiogenic 40Ar (40Ar*) to cosmogenic 38Ar or 36Ar (38Arcos or 36Arcos) is proportional to the difference between the radioisotopic and exposure ages, as well as the K/Ca ratio of the degassing phase. Thus cosmogenic, radiogenic, and trapped Ar isotopes, all of which can be measured remotely and are stable over geologic time, are sufficient to generate an isochron-like diagram from which the isotopic composition of the trapped component may be inferred. Such data also provide a means to assess the extent to which the system has remained closed with respect to 40Ar*, thereby mitigating otherwise unquantifiable uncertainties that complicate the conventional K-Ar dating method.

  1. Çok Etmenli Sistemlerde NetLogo İle Karınca Kolonisi Optimizasyonu

    Directory of Open Access Journals (Sweden)

    Mustafa Tüker

    2013-02-01

    Full Text Available Çok etmenli sistemler (ÇES, karmaşık optimizasyon problemlerinin modellenmesi ve çözülmesi için etkin bir yol sunarlar. Bu çalışmada, Gezgin Satıcı Problemi (GSP'ni çözmek için ÇES ve karınca kolonileri birlikte kullanılmıştır. Sistem benzetimi, etmen tabanlı bir programlama ortamı olan NetLogo ile gerçekleştirilmiştir. Problemin modellenmesi ve benzetimi için NetLogo'nun nasıl kullanılacağı kodlarla ayrıntılı olarak açıklanmıştır. Algoritma farklı düğüm sayıları için denenmiş ve elde edilen sonuçlar tartışılmıştır.

  2. K-Ar ages of some metamorphic rocks of Oban massif and their implications for the tectonothermal evolution of Southeastern Nigeria

    International Nuclear Information System (INIS)

    Ekwueme, B.N.; Itaya, Tetsumaru; Yabe, Hisatomo

    2000-01-01

    The following K-Ar ages have been obtained on mineral separates from some metamorphic rocks in the Oban massif: amphibolites (592-930 Ma), banded gneisses (492-538 Ma), granodioritic gneiss (502 Ma), schists (514-519 Ma) and charnockite (481 Ma). Comparison of these ages with previous dates obtained by the Rb-Sr whole rock method and the Pb-Pb evaporation technique on single zircon throws light on the cooling history and orogenic events in the Oban massif. The banded gneiss in the Oban massif yields a zircon age of 1932±5 Ma, indicating that it was emplaced during the early Proterozoic (Eburnean orogeny). The K-Ar age of 492-538 Ma suggests that these rocks were metamorphosed during the Pan-African orogeny. This age is similar to the Rb-Sr isochron age of 510±10 Ma earlier suggested to be the age of migmatization in the Oban massif. The amphibolite yielded Rb-Sr isochron ages of 784±31 Ma and 1313±37 Ma. The age of 1313±37 Ma fits into the Kibaran event. The K-Ar hornblende age of 930±37 Ma on the same amphibolite strongly suggests that this amphibolite belongs to an event older than Pan-African (600±150 Ma) and has not been reset perfectly by the Pan-African event. The migmatitic schists in the Oban massif yielded a Rb-Sr isochron age of 527±16 Ma which has been interpreted as the age of its migmatization. One sample of this schist, however, gave a model age of 676±24 Ma. The K-Ar ages for the Oban massif schists (514-519 Ma) are close to the Rb-Sr isochron age of ca. 527 Ma and confirm that a metamorphic event occurred in the area at this time. This was followed by final cooling at 515±10 Ma. Charnockite in the Oban area has yielded a zircon age of 584±20 Ma, which is Pan-African. The age possibly dates the time of formation of the charnockites. The K-Ar age (481 Ma) obtained in this study is approximately 100 Ma younger than the zircon age and possibly dates the subsequent cooling of the charnockite through hornblende blocking temperature. (author)

  3. Modulation of GABA receptors expressed in Xenopus oocytes by 13-L-hydroxylinoleic acid and food additives.

    Science.gov (United States)

    Aoshima, H; Tenpaku, Y

    1997-12-01

    To study the effects of 13-L-hydroxylinoleic acid (LOH) and food additives on gamma-aminobutyric acid (GABA) receptors, ionotropic GABA receptors were expressed in Xenopus oocytes by injecting mRNAs prepared from rat whole brain. LOH, which was prepared by reduction of 13-L-hydroperoxylinoleic acid (LOOH), inhibited the response of GABA receptors in the presence of high concentrations of GABA. LOH also inhibited nicotinic acetylcholine, glycine, and kainate receptors, while it had little effect on NMDA receptors expressed in Xenopus oocytes. However, LOH potentiated the response of GABA receptors as well as LOOH in the presence of low concentrations of GABA, possibly increasing the affinity of GABA for the receptors, while linoleic acid did not. Since some modification of the compounds seemed to change their effects on GABA receptors, the responses of GABA receptors elicited by 10 microM GABA were measured in the presence of compounds with various kinds of functional groups or the structural isomers of pentanol. Potentiation of GABA receptors depended strongly on the species of functional groups and also depended on the structure of the isomers. Then effects of various kinds of food additives on GABA receptors were also examined; perfumes such as alcohols or esters potentiated the responses strongly, while hexylamine, nicotinamide, or caffeine inhibited the responses, mainly in a competitive manner, and vanillin inhibited the responses noncompetitively. These results suggest the possibility that production of LOOH and LOH, or intake of much of some food additives, modulates the neural transmission in the brain, especially through ionotropic GABA receptors and changes the frame of the human mind, as alcohol or tobacco does.

  4. Role of glutamate receptors and nitric oxide on the effects of glufosinate ammonium, an organophosphate pesticide, on in vivo dopamine release in rat striatum.

    Science.gov (United States)

    Faro, Lilian R F; Ferreira Nunes, Brenda V; Alfonso, Miguel; Ferreira, Vania M; Durán, Rafael

    2013-09-15

    The purpose of the present work was to assess the possible role of glutamatergic receptors and nitric oxide (NO) production on effects of glufosinate ammonium (GLA), an organophosphate pesticide structurally related to glutamate, on in vivo striatal dopamine release in awake and freely moving rats. For this, we used antagonists of NMDA (MK-801 and AP5) or AMPA/kainate (CNQX) receptors, or nitric oxide synthase (NOS) inhibitors (l-NAME and 7-NI), to study the effects of GLA on release of dopamine from rat striatum. So, intrastriatal infusion of 10mM GLA significantly increased dopamine levels (1035±140%, compared with basal levels) and administration of GLA to MK-801 (250μM) or AP5 (650μM) pretreated animals, produced increases in dopamine overflow that were ∼40% and ∼90% smaller than those observed in animals not pretreated with MK-801 or AP5. Administration of GLA to CNQX (500μM) pretreated animals produced an effect that was not significantly different from the one produced in animals not pretreated with CNQX. On the other hand, administration of GLA to l-NAME (100μM) or 7-NI (100μM) pretreated animals, produced increases in dopamine overflow that were ∼80% and ∼75% smaller than those observed in animals not pretreated with these inhibitors. In summary, GLA appears to act, at least in part, through an overstimulation of NMDA (and not AMPA/kainate) receptors with possible NO production to induce in vivo dopamine release. Administration of NMDA receptor antagonists and NOS inhibitors partially blocks the release of dopamine from rat striatum. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  5. Somatostatin receptors

    DEFF Research Database (Denmark)

    Møller, Lars Neisig; Stidsen, Carsten Enggaard; Hartmann, Bolette

    2003-01-01

    functional units, receptors co-operate. The total receptor apparatus of individual cell types is composed of different-ligand receptors (e.g. SRIF and non-SRIF receptors) and co-expressed receptor subtypes (e.g. sst(2) and sst(5) receptors) in characteristic proportions. In other words, levels of individual......-peptides, receptor agonists and antagonists. Relatively long half lives, as compared to those of the endogenous ligands, have been paramount from the outset. Motivated by theoretical puzzles or the shortcomings of present-day diagnostics and therapy, investigators have also aimed to produce subtype...

  6. K-Ar age data and geochemistry of the Kiwitahi Volcanics, western Hauraki Rift, North Island, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Black, P M [Department of Geology, Auckland University, Auckland (New Zealand); Briggs, R M [Department of Earth Sciences, Waikato University, Hamilton (New Zealand); Itaya, T [Hiruzen Research Institute, Okayama University of Science, Okayama (Japan); Dewes, E R [Department of Earth Sciences, Waikato University, Hamilton (New Zealand); Dunbar, H M [Department of Earth Sciences, Waikato University, Hamilton (New Zealand); Kawasaki, K [Hiruzen Research Institute, Okayama University of Science, Okayama (Japan); Kuschel, E [Department of Geology, Auckland University, Auckland (New Zealand); Smith, I E.M. [Department of Geology, Auckland University, Auckland (New Zealand)

    1992-07-01

    The Kiwitahi Volcanics of late Miocene age crop out in a number of localities situated along the western side of the Hauraki Rift in northern North Island, New Zealand. They extend from Waiheke Island in the north to Te Tapui in the south. From 19 new K-Ar ages presented here and geochemical data from volcanics at each locality, it is suggested that the Kiwitahi Volcanics should be informally subdivided into five groups: (1) an oldest group of agglomerates and volcanic breccias at northeastern Waiheke, containing pyroxene and hornblende andesites with an age range of 14.4-16.02 Ma; (2) a volcanic centre at Stony Batter (6.85-8.34 Ma) comprised of olivine basaltic andesites which should be assigned to the geochemically and temporally similar Ti Point Volcanics; (3) a group including the andesitic breccias at Ness Valley and the volcanic centres of Miranda (pyroxene basaltic andesite, pyroxene and hornblende andesite, hornblende dacite) and Pukekamaka (hornblende andesites), all within the age range 10.22-12.96 Ma; (4) a separate group at Tahuna (6.36-6.80 Ma) consisting of pyroxene basaltic andesites and pyroxene andesites; and (5) a southern group of Maungatapu, Ruru, Maungakawa, and Te Tapui (5.52-6.23 Ma), forming eroded cones of olivine basaltic andesites, pyroxene basaltic andesites, and pyroxene andesites. The Kiwitahi Volcanics of late Miocene age crop out in a number of localities situated along the western side of the Hauraki Rift in northern North Island, New Zealand. They extend from Waiheke Island in the north to Te Tapui in the south. From 19 new K-Ar ages presented here and geochemical data from volcanics at each locality, it is suggested that the Kiwitahi Volcanics should be informally subdivided into five groups: (1) an oldest group of agglomerates and volcanic breccias at northeastern Waiheke, containing pyroxene and hornblende andesites with an age range of 14.4-16.02 Ma; (2) a volcanic centre at Stony Batter (6.85-8.34 Ma) comprised of olivine

  7. K-Ar age data and geochemistry of the Kiwitahi Volcanics, western Hauraki Rift, North Island, New Zealand

    International Nuclear Information System (INIS)

    Black, P.M.; Briggs, R.M.; Itaya, T.; Dewes, E.R.; Dunbar, H.M.; Kawasaki, K.; Kuschel, E.; Smith, I.E.M.

    1992-01-01

    The Kiwitahi Volcanics of late Miocene age crop out in a number of localities situated along the western side of the Hauraki Rift in northern North Island, New Zealand. They extend from Waiheke Island in the north to Te Tapui in the south. From 19 new K-Ar ages presented here and geochemical data from volcanics at each locality, it is suggested that the Kiwitahi Volcanics should be informally subdivided into five groups: (1) an oldest group of agglomerates and volcanic breccias at northeastern Waiheke, containing pyroxene and hornblende andesites with an age range of 14.4-16.02 Ma; (2) a volcanic centre at Stony Batter (6.85-8.34 Ma) comprised of olivine basaltic andesites which should be assigned to the geochemically and temporally similar Ti Point Volcanics; (3) a group including the andesitic breccias at Ness Valley and the volcanic centres of Miranda (pyroxene basaltic andesite, pyroxene and hornblende andesite, hornblende dacite) and Pukekamaka (hornblende andesites), all within the age range 10.22-12.96 Ma; (4) a separate group at Tahuna (6.36-6.80 Ma) consisting of pyroxene basaltic andesites and pyroxene andesites; and (5) a southern group of Maungatapu, Ruru, Maungakawa, and Te Tapui (5.52-6.23 Ma), forming eroded cones of olivine basaltic andesites, pyroxene basaltic andesites, and pyroxene andesites. The Kiwitahi Volcanics of late Miocene age crop out in a number of localities situated along the western side of the Hauraki Rift in northern North Island, New Zealand. They extend from Waiheke Island in the north to Te Tapui in the south. From 19 new K-Ar ages presented here and geochemical data from volcanics at each locality, it is suggested that the Kiwitahi Volcanics should be informally subdivided into five groups: (1) an oldest group of agglomerates and volcanic breccias at northeastern Waiheke, containing pyroxene and hornblende andesites with an age range of 14.4-16.02 Ma; (2) a volcanic centre at Stony Batter (6.85-8.34 Ma) comprised of olivine

  8. The distribution of excitatory amino acid receptors on acutely dissociated dorsal horn neurons from postnatal rats.

    Science.gov (United States)

    Arancio, O; Yoshimura, M; Murase, K; MacDermott, A B

    1993-01-01

    Excitatory amino acid receptor distribution was mapped on acutely dissociated neurons from postnatal rat spinal cord dorsal horn. N-methyl D-aspartate, quisqualate and kainate were applied to multiple locations along the somal and dendritic surfaces of voltage-clamped neurons by means of a pressure application system. To partially compensate for the decrement of response amplitude due to current loss between the site of activation on the dendrite and the recording electrode at the soma, a solution containing 0.15 M KCl was applied on the cell bodies and dendrites of some cells to estimate an empirical length constant. In the majority of the cells tested, the dendritic membrane had regions of higher sensitivity to excitatory amino acid agonists than the somatic membrane, with dendritic response amplitudes reaching more than seven times those at the cell body. A comparison of the relative changes in sensitivity between each combination of two of the three excitatory amino acid agonists along the same dendrite showed different patterns of agonist sensitivity along the dendrite in the majority of the cells. These data were obtained from dorsal horn neurons that had developed and formed synaptic connections in vivo. They demonstrate that in contrast to observations made on ventral horn neurons, receptor density for all the excitatory amino acid receptors on dorsal horn neurons, including the N-methyl-D-aspartate receptor, are generally higher on the dendrites than on the soma. Further, these results are similar to those obtained from dorsal horn neurons grown in culture.

  9. K-Ar geochronology of mafic dyke swarms from the meridional part of Sao Francisco craton and implications on tectonic context

    International Nuclear Information System (INIS)

    Teixeira, W.; Kawashita, K.; Pecchio, M.; Tame, N.R.

    1988-01-01

    The southern region of the Sao Francisco Craton is made up of gneissic-granitoid terranes (mainly of amphibolite facies) associated with supracrustals, which can be separed into two crustal provinces, the oldest formed during the Archean (3-2-2.6 Ga.), and the youngest in the Early Proterozoic (2.4-2.0 Ga.). Mafic dyke swarms inject the basement complexes in the area west of Belo Horizonte city, but not the Late proterozoic Bambui sedimentary cover. These dykes show NNW, NW, WNW, NNE and ENE trends and are of anorogenic character. Most dykes are tholeiitic in composition. Metamorphic recrystallization at greenschist to amphibolite facies as well as minor hidrothermal and/or deuteric transformations are characteristics in the majority of the these dykes. About sixty K/Ar determinations have been performed on plagioclases, amphiboles and whole rocks. They are interpretated combining the use of K/Ar diagrams and histogram, and according to the crustal evolution proposed for the craton. The available radiometric data suggest that the main period of mafic intrusions took place in the Early proterozoic as supported by the apparent ages on amphiboles. However, the beginning of the Middle Proterozoic (1.7-1.5 Ga.) probably corresponds to a period of tensional tectonics as well. On the other hand, most ages obtained on plagioclases and whole rocks, can be associated with Late Proterozoic processes of argon gain or loss. The results are tectonicaly associated with crustal rifting of the continental mass. This two radiometric groupings are characteristic for the evolution of the Early proterozoic crustal provine and of the Mid-Proterozoic intracratonic Espinhaco System respectively. The youngest Late Proterozoic apparent ages associated with the reflections of the contemporaneous evolution of the Braziliano marginal mobile belt which is also suggested by the partial resetting of the K/Ar ages of basement rocks within the eastern part of the Sao Francisco Craton. (author) [pt

  10. Discordant K-Ar ages between hornblende and biotite from the Tanzawa tonalitic pluton in the southern Fossa Magna, central Japan

    International Nuclear Information System (INIS)

    Sato, Kohei; Shibata, Ken; Uchiumi, Shigeru

    1986-01-01

    K-Ar ages were determined for hornblende and biotite in three tonalites from the Tanzawa pluton in the southern Fossa Magna, central Japan. The two minerals show discordant ages of 10.1 and 10.7 Ma for hornblende and 4.6 - 5.1 Ma for biotite. The age data and field evidence indicate that the pluton was emplaced in the Tanzawa Group in Middle Miocene time and its slow cooling (ca. 50 deg C/Ma in average) resulted in younger ages of boitites than hornblendes due to lower closure temperature for biotite. (author)

  11. K-Ar dating celadonite: A contribution to timing of a very low-grade metamorphism in the Central Andes of Chile

    International Nuclear Information System (INIS)

    Belmar, M; Schmidt, S.; Frey, M

    2001-01-01

    Clay minerals have been used in several studies to date very low-grade metamorphism processes and hydrothermal episodes. The technique of using the K-Ar isotopic dating was demonstrated by many authors (e.g. Hunziker et al., 1986; Clauer et al., 1995; Kirschner et al 1995; Zhao et al., 1997; Glasmacher et al., 2001). White mica and illitic materials of different size are usually analysed, whereasceladonite mineral with high potassium content has been low developed and few data are published. Successful dating of continental Andean celadonite could mean that is possible to date the very low-grade metamorphism (zeolites facies) in which celadonites are very often observed (au)

  12. Hayıt (Vitex agnus-castus), Çam ve Karışım Çiçek Balının Bazı Kalite Kriterleri Açısından Karşılaştırılması

    OpenAIRE

    UÇAK KOÇ, Aytül; KARACAOĞLU, Mete; DOĞAN, Mustafa

    2017-01-01

    Bu araştırma, Aydın yöresinde üretilen hayıt balının bazı kalite parametrelerinin belirlenerek, çam ve karışım çiçek balları ile karşılaştırılması amacıyla gerçekleştirilmiştir. Çalışmada, Aydın ili sınırları içinde üretilmiş ve yeni hasat edilmiş hayıt balı, çam balı ve yöre arıcılarının Orta Anadolu’da ürettiği karışım çiçek ballarının bazı kimyasal parametreleri belirlenmiştir. Üç bal grubunda her bir özelliğe ait veriler basit varyans analizi (ANOVA) ile değerlendirilmiştir. Tüm özellikle...

  13. Caffeine and an adenosine A(2A) receptor antagonist prevent memory impairment and synaptotoxicity in adult rats triggered by a convulsive episode in early life.

    Science.gov (United States)

    Cognato, Giana P; Agostinho, Paula M; Hockemeyer, Jörg; Müller, Christa E; Souza, Diogo O; Cunha, Rodrigo A

    2010-01-01

    Seizures early in life cause long-term behavioral modifications, namely long-term memory deficits in experimental animals. Since caffeine and adenosine A(2A) receptor (A(2A)R) antagonists prevent memory deficits in adult animals, we now investigated if they also prevented the long-term memory deficits caused by a convulsive period early in life. Administration of kainate (KA, 2 mg/kg) to 7-days-old (P7) rats caused a single period of self-extinguishable convulsions which lead to a poorer memory performance in the Y-maze only when rats were older than 90 days, without modification of locomotion or anxiety-like behavior in the elevated-plus maze. In accordance with the relationship between synaptotoxicity and memory dysfunction, the hippocampus of these adult rats treated with kainate at P7 displayed a lower density of synaptic proteins such as SNAP-25 and syntaxin (but not synaptophysin), as well as vesicular glutamate transporters type 1 (but not vesicular GABA transporters), with no changes in PSD-95, NMDA receptor subunits (NR1, NR2A, NR2B) or alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor subunits (GluR1, GluR2) compared with controls. Caffeine (1 g/L) or the A(2A)R antagonist, KW6002 (3 mg/kg) applied in the drinking water from P21 onwards, prevented these memory deficits in P90 rats treated with KA at P7, as well as the accompanying synaptotoxicity. These results show that a single convulsive episode in early life causes a delayed memory deficit in adulthood accompanied by a glutamatergic synaptotoxicity that was prevented by caffeine or adenosine A(2A)R antagonists.

  14. The Role of GluK4 in Synaptic Plasticity and Affective Behavior in Mice

    Science.gov (United States)

    Catches, Justin Samuel

    Kainate receptors (KARs) are glutamate-gated ion channels that signal through both ionotropic and metabotropic pathways (Contractor et al., 2011). Combinations of five KAR subunits (GluK1-5) form tetrameric receptors with GluK1, GluK2, and GluK3 able to form functional homomeric channels. The high-affinity subunits, GluK4 and GluK5, do not form homomeric channels but modify the properties of heteromeric receptors. Expression of the GluK4 receptor subunit in the forebrain is restricted to the CA3 region of the hippocampus and dentate gyrus regions where KARs modulate synaptic plasticity. In this study, ablation of Grik4, which encodes GluK4, in mice reduced KAR synaptic currents and altered activation properties of postsynaptic receptors but left two forms of presynaptic short-term plasticity intact. Disruption of both Grik4 and Grik5 caused complete loss of the postsynaptic ionotropic KAR current and impaired presynaptic frequency facilitation. Additionally, KAR surface expression was altered at pre- and postsynaptic sites at the MF synapse. Despite the loss of ionotropic signaling, KAR-mediated inhibition of the slow afterhyperpolarization current, which is dependent on metabotropic signaling, was intact in CA3 neurons. Long-term potentiation at the MF-CA3 synapse was reduced, likely through a loss of KAR modulation of excitability of the presynaptic MF axons. Genetic variants in the human GRIK4 gene alter the susceptibility for affective disorders (Bloss and Hunter, 2010). We found that ablation of Grik4 in mice resulted in reduced anxiety and an antidepressant-like phenotype. In the elevated zero-maze, a test for anxiety and risk taking behavior, and in two anxiogenic tests, marble-burying and novelty-induced suppression of feeding, anxiety-like behavior was consistently reduced in knockout animals. In the forced swim, a test of learned helplessness used to determine depression-like behavior, knockout mice demonstrated significantly less immobility suggesting

  15. Cell-specific cre recombinase expression allows selective ablation of glutamate receptors from mouse horizontal cells.

    Directory of Open Access Journals (Sweden)

    Sebastian Ströh

    Full Text Available In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57, a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99% and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl. In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼ 50% in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼ 75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less

  16. Cell-Specific Cre Recombinase Expression Allows Selective Ablation of Glutamate Receptors from Mouse Horizontal Cells

    Science.gov (United States)

    Janssen-Bienhold, Ulrike; Schultz, Konrad; Cimiotti, Kerstin; Weiler, Reto; Willecke, Klaus; Dedek, Karin

    2013-01-01

    In the mouse retina, horizontal cells form an electrically coupled network and provide feedback signals to photoreceptors and feedforward signals to bipolar cells. Thereby, horizontal cells contribute to gain control at the first visual synapse and to the antagonistic organization of bipolar and ganglion cell receptive fields. However, the nature of horizontal cell output remains a matter of debate, just as the exact contribution of horizontal cells to center-surround antagonism. To facilitate studying horizontal cell function, we developed a knockin mouse line which allows ablating genes exclusively in horizontal cells. This knockin line expresses a Cre recombinase under the promoter of connexin57 (Cx57), a gap junction protein only expressed in horizontal cells. Consistently, in Cx57+/Cre mice, Cre recombinase is expressed in almost all horizontal cells (>99%) and no other retinal neurons. To test Cre activity, we crossbred Cx57+/Cre mice with a mouse line in which exon 11 of the coding sequence for the ionotropic glutamate receptor subunit GluA4 was flanked by two loxP sites (GluA4fl/fl). In GluA4fl/fl:Cx57+/Cre mice, GluA4 immunoreactivity was significantly reduced (∼50%) in the outer retina where horizontal cells receive photoreceptor inputs, confirming the functionality of the Cre/loxP system. Whole-cell patch-clamp recordings from isolated horizontal cell somata showed a reduction of glutamate-induced inward currents by ∼75%, suggesting that the GluA4 subunit plays a major role in mediating photoreceptor inputs. The persistent current in GluA4-deficient cells is mostly driven by AMPA and to a very small extent by kainate receptors as revealed by application of the AMPA receptor antagonist GYKI52466 and concanavalin A, a potentiator of kainate receptor-mediated currents. In summary, the Cx57+/Cre mouse line provides a versatile tool for studying horizontal cell function. GluA4fl/fl:Cx57+/Cre mice, in which horizontal cells receive less excitatory input

  17. (S)-2-Amino-3-(3-hydroxy-7,8-dihydro-6H-cyclohepta[d]isoxazol-4-yl)propionic acid, a potent and selective agonist at the GluR5 subtype of ionotropic glutamate receptors. Synthesis, modeling, and molecular pharmacology

    DEFF Research Database (Denmark)

    Brehm, Lotte; Greenwood, Jeremy R; Hansen, Kasper B

    2003-01-01

    )propionic acid (AMPA) but inactive at NMDA receptors. However, 4-AHCP was found to be much weaker than AMPA as an inhibitor of [(3)H]AMPA binding and to have limited effect in a [(3)H]kainic acid binding assay using rat cortical membranes. To shed light on the mechanism(s) underlying this quite enigmatic......, activated cloned AMPA receptor subunits GluR1o, GluR3o, and GluR4o with EC(50) values in the range 4.5-15 microM and the coexpressed kainate-preferring subunits GluR6 + KA2 (EC(50) = 6.4 microM). Compound 6, but not 7, proved to be a very potent agonist (EC(50) = 0.13 microM) at the kainate-preferring GluR5...... subunit, equipotent with (S)-2-amino-3-(5-tert-butyl-3-hydroxyisothiazol-4-yl)propionic acid [(S)-Thio-ATPA, 4] and almost 4 times more potent than (S)-2-amino-3-(5-tert-butyl-3-hydroxyisoxazol-4-yl)propionic acid [(S)-ATPA, 3]. Compound 6 thus represents a new structural class of GluR5 agonists...

  18. Sm-Nd, Rb-Sr and K-Ar age constraints of the El Molle and Barroso plutons, western Sierra de San Luis, Argentina

    International Nuclear Information System (INIS)

    Sato, A.M.; Gonzalez, P.D; Petronilho, L.A; Llambias, E.J.; Varela, R; Basei, M.A.S

    2001-01-01

    Within the Early Paleozoic Famatinian orogeny of Southern Sierras Pampeanas (Sierra de San Luis and Sierra de Cordoba), the post-orogenic granitoids are characterized by circular intrusions. The published Rb-Sr and K-Ar ages from plutons in the Sierra de San Luis range between 408 and 320 Ma (see synthesis in Llambias et al., 1998). The El Molle and Barroso plutons (Sims et al., 1997; Gonzalez and Sato, 2000) are the two main exposures of a post-orogenic intrusive complex located in the western area of the Sierra de San Luis basement. They also exhibit an overall circular map view of almost 8 km in diameter, and are emplaced in a metamorphic complex developed through pre-Famatinian (Proterozoic? to Early Paleozoic) to Famatinian (Early Paleozoic) orogenies (Gonzalez and Llambias, 1998; von Gosen and Prozzi, 1998). We are carrying out isotopic datings of the El Molle and Barroso plutons in order to contribute to the understanding of the magmatic and metamorphic evolution of the final stages of the Famatinian orogenic cycle in the Sierra de San Luis. The first results of the Sm-Nd, Rb-Sr and K-Ar dates are here presented (au)

  19. Mineralogy and clinoptilolite K/Ar results from Yucca Mountain, Nevada, USA: A potential high-level radioactive waste repository site

    International Nuclear Information System (INIS)

    WoldeGabriel, G.; Broxton, D.E.; Bish, D.L.; Chipera, S.J.

    1993-11-01

    The Yucca Mountain Site Characterization Project is investigating Yucca Mountain, Nevada, as a potential site for a high-level nuclear waste repository. An important aspect of this evaluation is to understand the geologic history of the site including the diagenetic processes that are largely responsible for the present-day chemical and physical properties of the altered tuffs. This study evaluates the use of K/Ar geochronology in determining the alteration history of the zeolitized portions of Miocene tuffs at Yucca Mountain. Clinoptilolite is not generally regarded as suitable for dating because of its open structure and large ion-exchange capacity. However, it is the most abundant zeolite at Yucca Mountain and was selected for this study to assess the feasibility of dating the zeolitization process and/or subsequent processes that may have affected the zeolites. In this study we examine the ability of this mineral to retain all or part of its K and radiogenic Ar during diagenesis and evaluate the usefulness of the clinoptilolite K/Ar dates for determining the history of alteration

  20. The tectonic significance of K/Ar illite fine-fraction ages from the San Luis Formation (Eastern Sierras Pampeanas, Argentina)

    Science.gov (United States)

    Wemmer, Klaus; Steenken, André; Müller, Stefan; de Luchi, Mónica G. López; Siegesmund, Siegfried

    2011-04-01

    The Sierra de San Luis forms the southern tip of the Eastern Sierras Pampeanas in central Argentina. Two narrow belts of low-grade phyllites and quartz arenites, i.e. the San Luis Formation, have accommodated part of the strain-related differential exhumation of the medium- to high-grade metamorphic domains that constitute to the basement complex of the sierra. Eleven phyllite samples were subjected to the K/Ar fine-fraction dating technique. Results are interpreted in relation to the Kübler index of the illites, which indicate epimetamorphic conditions for the majority of the samples. Obtained ages between 330 and 290 Ma cover a period of compressional tectonics in the late Mississippian (Visean/Serpukhovian boundary) followed by the subsidence during the formation of the Paganzo Basin in the provinces of La Rioja and San Luis. These tectonic movements are coincident with the Toco orogeny in northern Chile and southern Bolivia. This suggests that the older K/Ar ages document the compressional stage and that younger ages record the cooling of the basement during the subsequent extensional uplift of the basement.

  1. K-Ar ages of basalts from the Higashi-Matsuura district, northwestern Kyushu, Japan and regional geochronology of the Cenozoic alkaline volcanic rocks in eastern Asia

    International Nuclear Information System (INIS)

    Nakamura, Eizo; Campbell, I.H.; McDougall, I.

    1986-01-01

    Seven new K-Ar age determinations are presented on whole rock samples from alkaline and tholeiitic basalts of the Higashi-Matsuura district, northwestern Kyushu, Japan. Ages obtained range from 2.92 ± 0.03 Ma to 3.01 ± 0.04 Ma; these ages are essentially identical within analytical errors and yield an average age of 2.98 ± 0.03 Ma (Late Pliocene). When combined on an isochron type diagram the six Higashi-Matsuura samples give an age of 3.00 ± 0.03 Ma with the composition of nonradiogenic 40 Ar/ 36 Ar = 294.2 ± 2.0. The excellent age agreement of samples with different K contents and petrographic characteristics provides strong evidence that the tholeiitic and alkaline basalts were erupted for an extremely short period in the Higashi-Matsuura district. A basalt from Ogawashima Island yields a K-Ar age of 3.58 ± 0.04 Ma. This study and previously reported data support the hypothesis that alkaline volcanic activity in southwestern Japan commenced some 10 Ma ago and continued intermittently until recent times. Systematic variations of age and distribution of Cenozoic alkaline basalts are recognized in northeastern China, Korea and southwestern Japan. It is suggested that these variations are related to the initiation of 'mantle plumes' resulting from convection in the mantle wedge caused or controlled by subduction of the Kula and Pacific plates. (author)

  2. XIX-wieczne badania ludoznawcze na obszarze Łotwy w świetle korespondencji Stefanii Ulanowskiej do Jana Karłowicza

    Directory of Open Access Journals (Sweden)

    Dorota Krystyna Rembiszewska

    2014-12-01

    Full Text Available 19th century ethnological research on the territory of Latvia in view of correspondence of Stefania Ulanowska to Jan Karłowicz Letters, which are the basis of the article, are a part of Jan Karlowicz’s (a 19th century ethnographer, lexicographer heritage kept in the historical archive in Vilnius. They are evidence of correspondence between Jan Karłowicz and Stefania Ulanowska, the author of Łotysze Inflant Polskich, a w szczególności z gminy wielońskiej powiatu rzeżyckiego since October 1889 until January 1890 during Ulanowska’s stay in the village of Wielony, now Viļāni (Latvia. The correspondence is a source of rich material including information about Ulanowska that has not been published so far as well as data of Latgale’s and its inhabitants’ past. Moreover, it is a unique evidence of scientific peregrinations. These letters have their contribution in ethnographic research on the former territory of Poland as they show circumstances and methods of exploration used in the 19th century. At the same time they can be an interesting gloss for research over Latgalian dialects as far as names of material culture are concerned.   XIX-wieczne badania ludoznawcze na obszarze Łotwy w świetle korespondencji Stefanii Ulanowskiej do Jana Karłowicza Listy, stanowiące podstawę omówienia, pochodzą ze spuścizny Jana Karłowicza (XIX-wiecznego etnografa, leksykografa przechowywanej w litewskim archiwum historycznym w Wilnie. Są one świadectwem korespondencji prowadzonej przez Jana Karłowicza i Stefanię Ulanowską – m.in. autorkę Łotyszy Inflant Polskich, a w szczególności z gminy wielońskiej powiatu rzeżyckiego, od października 1889 r. do stycznia 1890 r. podczas pobytu badaczki w miejscowości Wielony, obecnie Viļāni (Łotwa. Korespondencja ta dostarcza dość bogatego materiału, zawierającego informacje dotychczas niedrukowane na temat Ulanowskiej. Przynosi także sporo danych z przeszłości Łatgalii i jej

  3. Receptor assay

    Energy Technology Data Exchange (ETDEWEB)

    Kato, K; Ibayashi, H [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1975-05-01

    This paper summarized present status and problems of analysis of hormone receptor and a few considerations on clinical significance of receptor abnormalities. It was pointed that in future clinical field quantitative and qualitative analysis of receptor did not remain only in the etiological discussion, but that it was an epoch-making field of investigation which contained the possiblity of artificial change of sensitivity of living body on drugs and the development connected directly with treatment of various diseases.

  4. Quantitative Potassium Measurements with Laser-Induced Breakdown Spectroscopy Using Low-Energy Lasers: Application to In Situ K-Ar Geochronology for Planetary Exploration.

    Science.gov (United States)

    Cho, Yuichiro; Horiuchi, Misa; Shibasaki, Kazuo; Kameda, Shingo; Sugita, Seiji

    2017-08-01

    In situ radiogenic isotope measurements to obtain the absolute age of geologic events on planets are of great scientific value. In particular, K-Ar isochrons are useful because of their relatively high technical readiness and high accuracy. Because this isochron method involves spot-by-spot K measurements using laser-induced breakdown spectroscopy (LIBS) and simultaneous Ar measurements with mass spectrometry, LIBS measurements are conducted under a high vacuum condition in which emission intensity decreases significantly. Furthermore, using a laser power used in previous planetary missions is preferable to examine the technical feasibility of this approach. However, there have been few LIBS measurements for K under such conditions. In this study, we measured K contents in rock samples using 30 mJ and 15 mJ energy lasers under a vacuum condition (10 -3  Pa) to assess the feasibility of in situ K-Ar dating with lasers comparable to those used in NASA's Curiosity and Mars 2020 missions. We obtained various calibration curves for K using internal normalization with the oxygen line at 777 nm and continuum emission from the laser-induced plasma. Experimental results indicate that when K 2 O laser energy, with a detection limit of 88 ppm and 20% of error at 2400 ppm of K 2 O. Futhermore, the calibration curve based on the K 769 nm line intensity normalized with continuum emission yielded the best result for the 15 mJ laser, giving a detection limit of 140 ppm and 20% error at 3400 ppm K 2 O. Error assessments using obtained calibration models indicate that a 4 Ga rock with 3000 ppm K 2 O would be measured with 8% (30 mJ) and 10% (15 mJ) of precision in age when combined with mass spectrometry of 40 Ar with 10% of uncertainty. These results strongly suggest that high precision in situ isochron K-Ar dating is feasible with a laser used in previous and upcoming Mars rover missions.

  5. 40Ar/39Ar and K-Ar age constraints on the timing of regional deformation, south coast of New South Wales, Lachlan Fold Belt: problems and implications

    International Nuclear Information System (INIS)

    Fergusson, C.L.; Phillips, D.

    2001-01-01

    Four slate samples from subduction complex rocks exposed on the south coast of New South Wales, south of Batemans Bay, were analysed by K-Ar and 40 Ar/ 39 Ar step-heating methods, One sample contains relatively abundant detrital muscovite flakes that are locally oblique to the regional cleavage in the rock, whereas the remaining samples appear to contain sparse detrital muscovite. Separates of detrital muscovite yielded plateau ages of 505 + 3 Ma and 513 + 3 Ma indicating that inheritance has not been eliminated by metamorphism and recrystallisation. Step-heating analyses of whole-rock chips from all four slate samples produced discordant apparent age spectra with 'saddle shapes' following young apparent ages at the lowest temperature increments. Elevated apparent ages associated with the highest temperature steps are attributed to the presence of variable quantities of detrital muscovite ( 40 Ar/ 39 Ar integrated ages of ca 455Ma, which are some 15-30 million years older than K-Ar ages for the same samples. These discrepancies suggest that the slates have also been affected by recoil loss/redistribution of 39 Ar, Ieading to anomalously old 40 Ar/ 39 Ar ages. Two other samples, from slaty tectonic melange and intensely cleaved slate, yielded average 40 Ar/ 39 Ar integrated ages of ca 424Ma, which are closer to associated mean K-Ar ages of 423 + 4Ma and 409 + 16Ma, respectively. Taking into account the potential influences of recoil loss/redistribution of 39 Ar and inheritance, the results from the latter samples suggest a maximum age of ca 440 Ma for deformation/metamorphism. The current results indicate that recoil and inheritance problems may also have affected whole-rock 40 Ar/ 39 Ar data reported from other regions of the Lachlan Fold Belt. Therefore, until these effects are adequately quantified, models for the evolution of the Lachlan Fold Belt, that are based on such whole-rock 40 Ar/ 39 Ar data, should be treated with caution. Copyright (2001) Geological

  6. Tectono-metamorphic evolution of high-P/T and low-P/T metamorphic rocks in the Tia Complex, southern New England Fold Belt, eastern Australia: Insights from K-Ar chronology

    Science.gov (United States)

    Fukui, Shiro; Tsujimori, Tatsuki; Watanabe, Teruo; Itaya, Tetsumaru

    2012-10-01

    The Tia Complex in the southern New England Fold Belt is a poly-metamorphosed Late Paleozoic accretionary complex. It consists mainly of high-P/low-T type pumpellyite-actinolite facies (rare blueschist facies) schists, phyllite and serpentinite (T = 300 °C and P = 5 kbar), and low-P/high-T type amphibolite facies schist and gneiss (T = 600 °C and P Tia granodiorite). White mica and biotite K-Ar ages distinguish Carboniferous subduction zone metamorphism and Permian granitic intrusions, respectively. The systematic K-Ar age mapping along a N-S traverse of the Tia Complex exhibits a gradual change. The white mica ages become younger from the lowest-grade zone (339 Ma) to the highest-grade zone (259 Ma). In contrast, Si content of muscovite changes drastically only in the highest-grade zone. The regional changes of white mica K-Ar ages and chemical compositions of micas indicate argon depletion from precursor high-P/low-T type phengitic white mica during the thermal overprinting and recrystallization by granitoids intrusions. Our new K-Ar ages and available geological data postulate a model of the eastward rollback of a subduction zone in Early Permian. The eastward shift of a subduction zone system and subsequent magmatic activities of high-Mg andesite and adakite might explain formation of S-type granitoids (Hillgrove suite) and coeval low-P/high-T type metamorphism in the Tia Complex.

  7. 6061 Alüminyum Alaşımının Sürtünme Karıştırma Kaynak Yöntemi ile Kaynak Edilebilirliğinin İncelenmesi

    Directory of Open Access Journals (Sweden)

    İlker EKER

    2009-02-01

    Full Text Available Bu çalışmada sürtünme karıştırma kaynağı yöntemiyle birleştirilen alüminyum döküm levhaların kaynak bölgelerinin değişen parametrelerle mikrosertlik ve mekanik özellikleri incelenmiştir. Kaynak süresince karıştırıcı ucun devir sayısı ve kaynak ilerleme hızı değişken parametreler olarak alınmıştır. Alüminyum alaşımlı levhaların kaynağında SAE 8620 malzeme numaralı sementasyon çeliğinden imal edilmiş karıştırıcı uç kullanılmıştır. Karıştırıcı ucun devir hızı sabitken kaynak ilerleme hızı dört farklı değerde seçilmiştir. Kaynaklı birleştirmelere metalografik ve mekanik testler yapılarak işlem parametrelerinin etkileri araştırılmıştır.

  8. Coenzyme Q10 instilled as eye drops on the cornea reaches the retina and protects retinal layers from apoptosis in a mouse model of kainate-induced retinal damage.

    Science.gov (United States)

    Lulli, Matteo; Witort, Ewa; Papucci, Laura; Torre, Eugenio; Schipani, Christian; Bergamini, Christian; Dal Monte, Massimo; Capaccioli, Sergio

    2012-12-17

    To evaluate if coenzyme Q10 (CoQ10) can protect retinal ganglion cells (RGCs) from apoptosis and, when instilled as eye drops on the cornea, if it can reach the retina and exert its antiapoptotic activity in this area in a mouse model of kainate (KA)-induced retinal damage. Rat primary or cultured RGCs were subjected to glutamate (50 μM) or chemical hypoxia (Antimycin A, 200 μM) or serum withdrawal (FBS, 0.5%) in the presence or absence of CoQ10 (10 μM). Cell viability was evaluated by light microscopy and fluorescence-activated cell sorting analyses. Apoptosis was evaluated by caspase 3/7 activity and mitochondrion depolarization tetramethylrhodamine ethyl ester analysis. CoQ10 transfer to the retina following its instillation as eye drops on the cornea was quantified by HPLC. Retinal protection by CoQ10 (10 μM) eye drops instilled on the cornea was then evaluated in a mouse model of KA-induced excitotoxic retinal cell apoptosis by cleaved caspase 3 immunohistofluorescence, caspase 3/7 activity assays, and quantification of inhibition of RGC loss. CoQ10 significantly increased viable cells by preventing RGC apoptosis. Furthermore, when topically applied as eye drops to the cornea, it reached the retina, thus substantially increasing local CoQ10 concentration and protecting retinal layers from apoptosis. The ability of CoQ10 eye drops to protect retinal cells from apoptosis in the mouse model of KA-induced retinal damage suggests that topical CoQ10 may be evaluated in designing therapies for treating apoptosis-driven retinopathies.

  9. Asetonitril-Su İkili Karışımlarında Piroksikam ve Tenoksikam'ın Potansiyometrik pKa Tayini

    OpenAIRE

    Çubuk Demiralay, Ebru; Yılmaz, Hülya

    2012-01-01

    İyonlaşma sabiti (pKa) çözünebilirlik sınırlaması olmaksızın doğru tahmin edilebilen parametrelerden birisidir. Sunulan bu çalışmada, piroksikam ve tenoksikamın asit- baz davranışı çalışılmıştır. Potansiyometrik metot kullanılarak, piroksikam ve tenoksikamın pKa değerleri asetonitril-su ikili karışımlarının farklı yüzdelerinde tayin edilmiştir (asetonitril içeriği hacimce % 30 ile 45 arasında). Bu bileşiklerin sudaki pKa değerleri mol kesri ve Yasuda-Shedlovsky eşitlikleri kullanarak hesaplan...

  10. Temps, Espace et la Eeprésentation de la Subjectivité Dans les Films de Wong Kar-wai

    Directory of Open Access Journals (Sweden)

    MOREIRA MACEDO, Ludmila

    2006-12-01

    Full Text Available Given the importance of the filmmaker Wong Kar-wai not only in the panorama of the cinema of Hong Kong, but in the contemporary cinematographic production as a whole, this paper proposes an analysis of his work concentrated on the problem of the identity of his characters. What we may call the «wongian subject” can be analyzed through various elements such as the tension between past, present and future, the relationship to public and private space, the changes of the perception of time and memory. Another important question that is analyzed is the relationship of the films with the social and political context of contemporary Hong Kong, because the topics of love, loneliness and alienation which invade the protagonists find relation in the transnational character of the Asian cinema and the fusion – often problematic – between Orient and Occident.

  11. Successive reactivation of older structures under variable heat flow conditions evidenced by K-Ar fault gouge dating in Sierra de Ambato, northern Argentine broken foreland

    Science.gov (United States)

    Nóbile, Julieta C.; Collo, Gilda; Dávila, Federico M.; Martina, Federico; Wemmer, Klaus

    2015-12-01

    The Argentine broken foreland has been the subject of continuous research to determine the uplift and exhumation history of the region. High-elevation mountains are the result of N-S reverse faults that disrupted a W-E Miocene Andean foreland basin. In the Sierra de Ambato (northern Argentine broken foreland) the reverse faults offset Neogene sedimentary rocks (Aconquija Fm., ˜9 Ma) and affect the basement comprising Paleozoic metamorphic rocks that have been dated at ˜477-470 Ma. In order to establish a chronology of these faults affecting the previous continuous basin we date the formation age of clay minerals associated with fault gouge using the K-Ar dating technique. Clay mineral formation is a fundamental process in the evolution of faults under the brittle regime (history with a minimum age of ˜360 Ma and a last clay minerals forming event at ˜220 Ma. Moreover, given the progression of apparent ages decreasing from coarse to fine size fractions (˜360-311 Ma for 2-1 μm grain size fraction, ˜326-286 Ma for 1-0.2 μm and ˜291-219 Ma of <0.2 μm), we modeled discrete deformation events at ˜417 Ma (ending of the Famatinian cycle), ˜317-326 Ma (end of Gondwanic orogeny), and ˜194-279 Ma (Early Permian - Jurassic deformation). According to our data, the Neogene reactivation would not have affected the K-Ar system neither generated a significant clay minerals crystallization in the fault gouge, although an exhumation of more than 2 Km is recorded in this period from stratigraphic data.

  12. Phanerozoic polyphase orogenies recorded in the northeastern Okcheon Belt, Korea from SHRIMP U-Pb detrital zircon and K-Ar illite geochronologies

    Science.gov (United States)

    Jang, Yirang; Kwon, Sanghoon; Song, Yungoo; Kim, Sung Won; Kwon, Yi Kyun; Yi, Keewook

    2018-05-01

    We present the SHRIMP U-Pb detrital zircon and K-Ar illite 1Md/1M and 2M1 ages, suggesting new insight into the Phanerozoic polyphase orogenies preserved in the northeastern Okcheon Belt, Korea since the initial basin formation during Neoproterozoic rifting through several successive contractional orogens. The U-Pb detrital zircon ages from the Early Paleozoic strata of the Taebaeksan Zone suggest a Cambrian maximum deposition age, and are supported by trilobite and conodont biostratigraphy. Although the age spectra from two sedimentary groups, the Yeongwol and Taebaek Groups, show similar continuous distributions from the Late Paleoproterozoic to Early Paleozoic ages, a Grenville-age hiatus (1.3-0.9 Ga) in the continuous stratigraphic sequence from the Taebaek Group suggests the existence of different peripheral clastic sources along rifted continental margin(s). In addition, we present the K-Ar illite 1Md/1M ages of the fault gouges, which confirm fault formation/reactivation during the Late Cretaceous to Early Paleogene (ca. 82-62 Ma) and the Early Miocene (ca. 20-18 Ma). The 2M1 illite ages, at least those younger than the host rock ages, provide episodes of deformation, metamorphism and hydrothermal effects related to the tectonic events during the Devonian (ca.410 Ma) and Permo-Triassic (ca. 285-240 Ma). These results indicate that the northeastern Okcheon Belt experienced polyphase orogenic events, namely the Okcheon (Middle Paleozoic), Songrim (Late Paleozoic to Early Mesozoic), Daebo (Middle Mesozoic) and Bulguksa (Late Mesozoic to Early Cenozoic) Orogenies, reflecting the Phanerozoic tectonic evolution of the Korean Peninsula along the East Asian continental margin.

  13. Transition of neogene arc volcanism in central-western Hokkaido, viewed from K-Ar ages, style of volcanic activity, and bulk rock chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, Wataru; Iwasaki, Miyuki; Nakagawa, Mitsuhiro [Hokkaido Univ., Sapporo (Japan)

    2000-02-01

    Spatial and temporal variations in late Cenozoic volcanism of southwestern Hokkaido at the northern end of NE-Japan arc have been clarified by 261 K-Ar and 76 FT ages including 49 newly determined K-Ar ages, volcanic stratigraphy, physical volcanology and whole-rock geochemistry. Arc volcanism characterized by rocks with low-Ti and Nb, and by across-arc increase in K{sub 2}O content in these rocks has continued at least since 12 Ma. Based on volcanic stratigraphy, physical volcanology and whole-rock geochemistry, volcanism after 12 Ma can be subdivided into 4 stages, 12-5, 5-1.7, and 1.7-0 Ma. The volcanism from 12 Ma to 5 Ma extended northward widely compared with distribution of Quaternary arc volcanism (1.7-0 Ma). This suggests that the arc trench junction between Kuril and NE-Japan arc's trenches was located about 100 km northward from the present position. Since around 5 Ma until 1.7 Ma, different type of volcanism under local extension field, characterized by a group of monogenetic volcanoes of alkali basalt and shield volcanoes of calc-alkaline andesite, had occurred at northern end of the volcanic region (Takikawa-Mashike region). During and after this volcanism, the northern edge of arc volcanism in the area has migrated southward. This suggests that the trench junction has migrated about 100 km southward since {approx}5 Ma. The quaternary arc volcanism (1.7-0 Ma) has been restricted at the southern part of the region. The volcanism since 12 Ma might be influenced by oblique subduction of Pacific plate beneath Kuril arc, resulting in the formation of local back arc basin at the junction and to southward migration of the trench junction. (author)

  14. Dataciones radiometricas (14C y K/Ar del Teide y el Rift noroeste, Tenerife, Islas Canarias

    Directory of Open Access Journals (Sweden)

    Hansen, A.

    2003-08-01

    unstable slopes of Teide, it took place without any apparent response of the volcano; on the contrary, these eruptions seemed to progressively buttress and enhance the stability of Teide Volcano. Conversely, the occurrence of these flank eruptions, combined with the Pico Viejo and NW rift eruptions, poses a very high lava-flow risk to the now densely populated areas in north and west Tenerife, which have been almost entirely resurfaced during the past 20,000 years.El Teide, el edificio volcánico más alto del planeta (3.718 m sobre el nivel del mar, > 7 km desde el fondo oceánico después del Mauna Loa y Mauna Kea en las islas Hawaii, forma un complejo volcánico en el centro de la isla de Tenerife. Su actividad eruptiva reciente (últimos 20 Ka está asociada con la rama NO del rift triple (120" que ha configurado la etapa reciente de construcción de la isla. La mayoría de las erupciones de Tenerife en este período se han localizado en estas estructuras volcánicas, generando frecuentes y extensas coladas máficas y félsicas, muchas alcanzado la costa e invadiendo lo que es ahora una de las zonas más densamente pobladas de Tenerife y, probablemente, de cualquier isla oceánica del planeta. Sin embargo, y a pesar de los numerosos estudios y proyectos previos, falta aún información geológica básica para este importante sistema volcánico, en particular la datación de las diferentes erupciones que lo componen, con objeto de reconstruir el marco geocronológico indispensable para conocer su evolución y determinar científicamente los riesgos volcánicos, de perentoria necesidad habida cuenta de su naturaleza y entidad, y de la población potencialmente afectada. Nuevas dataciones de Carbono-14 y K/Ar aportan ahora importante información a este respecto. La mayoría de las erupciones de los últimos 20 Ka no están relacionadas con el estratovolcán Teide, que sólo ha tenido una hace 1.240 f 60 años -entre 663 y 943 AD una vez calibrada la edad-, sino con el

  15. Comparison of germination responses of Anigozanthos flavidus (Haemodoraceae), Gyrostemon racemiger and Gyrostemon ramulosus (Gyrostemonaceae) to smoke-water and the smoke-derived compounds karrikinolide (KAR1) and glyceronitrile.

    Science.gov (United States)

    Downes, Katherine S; Light, Marnie E; Pošta, Martin; Kohout, Ladislav; van Staden, Johannes

    2013-03-01

    A major germination-promoting chemical in smoke-water is 3-methyl-2H-furo[2,3-c]pyran-2-one (karrikinolide, KAR(1)). However, not all species that germinate in response to smoke-water are responsive to KAR(1), such as Tersonia cyathiflora (Gyrostemonaceae). In this study, a test was made of whether two Gyrostemon species (Gyrostemonaceae) that have previously been shown to respond to smoke-water, respond to KAR(1). If not, then the smoke-derived chemical that stimulates germination of these species is currently unknown. Recently, glyceronitrile was isolated from smoke-water and promoted the germination of certain Anigozanthos species (Haemodoraceae). Whether this chemical promotes Gyrostemon racemiger germination is also examined. Furthermore, an investigation was carried out into whether these species germinate in response to smoke-water derived from burning cellulose alone. Gyrostemon racemiger and G. ramulosus seeds were buried after collection and retrieved in autumn the following year when dormancy was alleviated and seeds had become responsive to smoke-water. Anigozanthos flavidus seeds were after-ripened at 35 °C to alleviate dormancy. Gyrostemon and Anigozanthos seeds were then tested with 'Seed Starter' smoke-water, KAR(1), glyceronitrile and cellulose-derived smoke-water. Although Gyrostemon racemiger, G. ramulosus and A. flavidus were all stimulated to germinate by 'Seed Starter' smoke-water, none of these species responded to KAR(1). Gyrostemon racemiger germination was not promoted by glyceronitrile. This is in contrast to A. flavidus, where glyceronitrile, at concentrations of 1-500 µm, promoted germination, although seedling growth was inhibited at ≥400 µm. Maximum A. flavidus germination occurred at glyceronitrile concentrations of 25-300 µm. Some Gyrostemon germination was promoted by cellulose-derived smoke-water. KAR(1) and glyceronitrile, chemicals in smoke-water that are known to stimulate germination in other species, did not promote the

  16. Akademisyen Ücretlerine İlişkin Karşılaştırmalı Bir Analiz A Comparative Analysis Concerned With Academic Salaries

    Directory of Open Access Journals (Sweden)

    Hilmi SÜNGÜ

    2013-09-01

    retilen hizmetin kalitesinin geliştirilmesi ile emeğin karşılığında elde edilen kazanç doğrudan ilişkili olarak görülmektedir. Benzer statülere sahip ve birbirine eşit sayılabilecek görevlerde çalışan bireylere orantılı ücretler verilmesi örgütsel adaletin bir gereğidir. Ancak kamuda; hizmetlerin çeşitliliği, çalışan sayısının fazlalığı, kurum sayısının çok olması gibi nedenler ücret dengesinin sağlanmasını güçleştirmektedir. Karşılaştırmalı çalışmalarda ücret adaletsizliğinden en çok etkilenen gruplardan birinin akademisyenler olduğu görülmektedir. Gelir adaletsizliğini ortadan kaldırmak ve cumhuriyetin kuruluşunun 100 yılında, 2023 vizyonuna ilişkin belirlenen iddialı hedeflere ulaşabilmek için yetenekli bireyleri akademisyenliğe özendirmek gerekmektedir. Ancak ulusal bazda kamu çalışanları arasında bir karşılaştırma yapıldığında üniversitede görev yapmakta olan öğretim elemanlarının özellikle son yıllarda diğer çalışanlara oranla yıllık ücret artışlarından yeterince yararlanamadığı, bu durumun akademisyenlik mesleğinden uzaklaşmalara neden olduğu öne sürülmektedir. Uluslararası bazda yapılan karşılaştırma yapıldığında ise, Türkiye’deki kamu üniversitelerinde görev yapmakta olan akademisyenlerin aldıkları ücretin ortalamaların altında olduğuna işaret edilmektedir. Bu çalışmada Türkiye’de kamu üniversitelerinde görev yapmakta olan akademisyenlerin aylık ücretlerinin mevcut durumuna ve yıllar içindeki değişimine yer verilecek, üniversite öğretim elemanlarının aylık ücretleri ve diğer kamu çalışanları arasında bu açıdan yapılan karşılaştırmalarla birlikte, Türkiye ile diğer ülkelerdeki üniversitelerde görev yapan akademisyenlerin aylık ücretleri mevcut durumu tartışılmaktadır.

  17. Effect of intrathecal non-NMDA EAA receptor antagonist LY293558 in rats: a new class of drugs for spinal anesthesia.

    Science.gov (United States)

    Von Bergen, Nicholas H; Subieta, Alberto; Brennan, Timothy J

    2002-07-01

    Excitatory amino acid receptors are important for both sensory and motor function in the spinal cord. We studied the effects of intrathecal LY293558, a competitive non-N-methyl-D-aspartate excitatory amino acid receptor antagonist, on motor and sensory function in rats to determine whether drugs blocking these receptors could potentially be used as alternative agents to local anesthetics for spinal anesthesia. Rats were tested before and 15-240 min after intrathecal injection of 5 nmol (in 10 microl) LY293558. Sensory function was tested at the hind paw using withdrawal response to pin prick and withdrawal to pinch with sharp forceps. Motor performance (ambulation, placing reflex, and Rotorod time), blood pressure, and heart rate were also evaluated. Some tests were repeated the next day. Responses after LY293558 were compared to injection of 40 microl bupivacaine, 0.75%. Pin-prick responses at the forepaw, chest, abdomen, hind leg, and hind paw were also examined after intrathecal LY293558. Intrathecal LY293558 blocked both sensory and motor responses through 180 min; complete recovery was present the following day. No change in blood pressure or heart rate occurred. The effects of LY293558 were more pronounced and sustained than those of bupivacaine. Segmental blockade of the response to pin prick was present after LY293558. Drugs like LY293558 that block alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA)/kainate receptors may be an alternative to local anesthetics for spinal anesthesia in humans.

  18. Developing a chronostratigraphic tool for climatic archives: absolute dating (K/Ar and 40Ar/39Ar) and paleo-magnetism applied to lavas

    International Nuclear Information System (INIS)

    Sasco, Romain

    2015-01-01

    The understanding of climatic mechanisms and rapid climate changes requires a high-resolution, robust, and precise timescale which allows long-distance and multi-archives correlations.An appropriate tool to construct such a timescale is provided by the Earth magnetic field (EMF). The EMF is independent from climatic variations and its past evolution, global at the surface of the Earth, is recorded by most of the geological/climatic archives. Sedimentary sequences provide continuous records of relative intensities of the EMF on timescales usually based on ice core age models or orbital tuning. Lavas, though discontinuously emitted through time, record the absolute intensity of the EMF during their cooling at the surface of the Earth. Lavas are dated using 2 complementary methods: 40 Ar/ 39 Ar and K-Ar, both independent from climatic parameters. Lavas have therefore the potential to deliver tie-points (age - paleo-intensity couples) enabling the time calibration of sedimentary sequences and their transfer onto absolute intensity scale and chronological time scale. This timescale can then be transferred to other climatic archives. The present study focusses on the last 200 ka with lavas sampled from young volcanoes of Ardeche (South Massif Central, France) and recent phases of volcanism in the Canary Islands. Lava flows from Ardeche provided un-exploitable paleo-intensity results and ages with large uncertainties. Therefore, they failed to provide suitable tie-points. However, our geochronological results evidence how crucial the combination of both the K-Ar and 40 Ar/ 39 Ar methods is to test the accuracy and geological meaning of the ages. Ardeche lavas have abundant mantellic and crustal xenoliths, potential carriers of excess 40 Ar*. Our study suggests that the argon excess is located in sites that decrepitate at low temperature (≤600 C). Because 40 Ar/ 39 Ar ages are not affected by excess 40 Ar*, they provide reliable results. The new age dataset indicates

  19. Updates of the KArLE Experiment: New Libs Calibration Under High Vacuum for the Quantification of Potassium in Basalt for In Situ Geochronology

    Science.gov (United States)

    Devismes, D.; Cohen, B. A.; Li, Z.-H.; Miller, J. S.

    2014-01-01

    In planetary exploration, in situ absolute geochronology is one of the main important measurements that needs to be accomplished. Until now, on Mars, the age of the surface is only determined by crater density counting, which gives relative ages. These ages can have a lot of uncertainty as they depend on many parameters. More than that, the curves must be ties to absolute ages. Thus far, only the lost lander Beagle 2 was designed to conduct absolute geochronology measurements, though some recent attempts using MSL Curiosity show that this investigation is feasible and should be strongly encouraged for future flight. Experimental: The Potassium (K)-Argon Laser Experiment (KArLE) is being developed at MSFC through the NASA Planetary Instrument Definition and Development Program (PIDDP). The goal of this experiment is to provide in situ geochronology based on the K-Ar method. A laser ablates a rock under high vacuum, creating a plasma which is sensed by an optical spectrometer to do Laser Induced Breakdown Spectroscopy (LIBS). The ablated material frees gases, including radiogenic 40Ar,which is measured by a mass spectrometer (MS). As the potassium is a content and the 40Ar is a quantity, the ablated mass needed in order to relate them. The mass is given by the product of the ablated volume by the density of this material. So we determine the mineralogy of the ablated material with the LIBS spectra and images and calculate its density. The volume of the pit is measured by using microscopy. LIBS measurement of K under high vacuum: Three independant projects [1, 2, 3] including KArLE, are developing geochronological instruments based on this LA-LIBS-MS method. Despite several differences in their setup, all of them have validated the methods with analyses and ages. However, they all described difficulties with the LIBS measurements of K [3,4]. At ambient pressure, the quantification of K by LIBS on geological materials can be accurate [5]. However the protocol of the LA

  20. Transmitter receptors reveal segregation of the arcopallium/amygdala complex in pigeons (Columba livia).

    Science.gov (United States)

    Herold, Christina; Paulitschek, Christina; Palomero-Gallagher, Nicola; Güntürkün, Onur; Zilles, Karl

    2018-02-15

    At the beginning of the 20th century it was suggested that a complex group of nuclei in the avian posterior ventral telencephalon is comparable to the mammalian amygdala. Subsequent findings, however, revealed that most of these structures share premotor characteristics, while some indeed constitute the avian amygdala. These developments resulted in 2004 in a change of nomenclature of these nuclei, which from then on were named arcopallial or amygdala nuclei and referred to as the arcopallium/amygdala complex. The structural basis for the similarities between avian and mammalian arcopallial and amygdala subregions is poorly understood. Therefore, we analyzed binding site densities for glutamatergic AMPA, NMDA and kainate, GABAergic GABA A , muscarinic M 1 , M 2 and nicotinic acetylcholine (nACh; α 4 β 2 subtype), noradrenergic α 1 and α 2 , serotonergic 5-HT 1A and dopaminergic D 1/5 receptors using quantitative in vitro receptor autoradiography combined with a detailed analysis of the cyto- and myelo-architecture. Our approach supports a segregation of the pigeon's arcopallium/amygdala complex into the following subregions: the arcopallium anterius (AA), the arcopallium ventrale (AV), the arcopallium dorsale (AD), the arcopallium intermedium (AI), the arcopallium mediale (AM), the arcopallium posterius (AP), the nucleus posterioris amygdalopallii pars basalis (PoAb) and pars compacta (PoAc), the nucleus taeniae amgygdalae (TnA) and the area subpallialis amygdalae (SpA). Some of these subregions showed further subnuclei and each region of the arcopallium/amygdala complex are characterized by a distinct multi-receptor density expression. Here we provide a new detailed map of the pigeon's arcopallium/amygdala complex and compare the receptor architecture of the subregions to their possible mammalian counterparts. © 2017 Wiley Periodicals, Inc.

  1. The 40Ar/39Ar and K/Ar dating of lavas from the Hilo 1-km core hole, Hawaii Scientific Drilling Project

    Science.gov (United States)

    Sharp, W.D.; Turrin, B.D.; Renne, P.R.; Lanphere, M.A.

    1996-01-01

    Mauna Kea lava flows cored in the HilIo hole range in age from <200 ka to about 400 ka based on 40Ar/39Ar incremental heating and K-Ar analyses of 16 groundmass samples and one coexisting plagioclase. The lavas, all subaerially deposited, include a lower section consisting only of tholeiitic basalts and an upper section of interbedded alkalic, transitional tholeiitic, and tholeiitic basalts. The lower section has yielded predominantly complex, discordant 40Ar/39Ar age spectra that result from mobility of 40Ar and perhaps K, the presence of excess 40Ar, and redistribution of 39Ar by recoil. Comparison of K-Ar ages with 40Ar/39Ar integrated ages indicates that some of these samples have also lost 39Ar. Nevertheless, two plateau ages of 391 ?? 40 and 400 ?? 26 ka from deep in the hole, combined with data from the upper section, show that the tholeiitic section accumulated at an average rate of about 7 to 8 m/kyr and has an mean recurrence interval of 0.5 kyr/flow unit. Samples from the upper section yield relatively precise 40Ar/39Ar plateau and isotope correlation ages of 326 ?? 23, 241 ?? 5, 232 ?? 4, and 199 ?? 9 ka for depths of -415.7 m to -299.2 m. Within their uncertainty, these ages define a linear relationship with depth, with an average accumulation rate of 0.9 m/kyr and an average recurrence interval of 4.8 kyr/flow unit. The top of the Mauna Kea sequence at -280 m must be older than the plateau age of 132 ?? 32 ka, obtained for the basal Mauna Loa flow in the corehole. The upward decrease in lava accumulation rate is a consequence of the decreasing magma supply available to Mauna Kea as it rode the Pacific plate away from its magma source, the Hawaiian mantle plume. The age-depth relation in the core hole may be used to test and refine models that relate the growth of Mauna Kea to the thermal and compositional structure of the mantle plume.

  2. A reconnaissance Rb-Sr, Sm-Nd, U-Pb, and K-Ar study of some host rocks and ore minerals in the West Shasta Cu- Zn district, California ( USA).

    Science.gov (United States)

    Kistler, R.W.; McKee, E.H.; Futa, K.; Peterman, Z.E.; Zartman, R.E.

    1985-01-01

    The Copley Greenstone, Balaklala Rhyolite, and Mule Mountain stock in the West Shasta Cu-Zn district, California, have Rb-Sr, Sm-Nd, U-Pb, and K-Ar systematics that indicate they are a cogenetic suite of ensimatic island-arc rocks about 400 Ma. Pervasive alteration and mineralization of these rocks, for the most part, was syngenetic and the major component of the mineralizing fluid was Devonian seawater. K-Ar ages of quarz-sericite concentrates from ore horizons and Rb-Sr systematics of a few rock and ore specimens record a later thermal and mineralizing event in the district of about 260 Ma. Contamination of some rocks with pelagic sediments is indicated by the Sm-Nd data. -Authors

  3. An arid episod in the climatic evolution of the Atakor mountains (Hoggar) about 1.5 m.y. (K/Ar datations). Its signification in the paleoclimatic context during the Plio-Pleistocene of Africa

    International Nuclear Information System (INIS)

    Rognon, Pierre; Gourinard, Yves; Bandet, Y.

    1981-01-01

    Nine K/Ar datations of some basaltic lavas from the Atakor mountains allow to date, for the first time, an arid period at 1.5 m.y. +- 0.1. This arid period takes place after the drying of the Plio-Pleistocene tropical lakes and after the first cool Pluvial, during an important turning phase of the geomorphologic and climatic evolution. These environmental changes are similar to those pointed out in Eastern Africa [fr

  4. Nd and Sr isotopes and K-Ar ages of the Ulreungdo alkali volcanic rocks in the East Sea, South Korea

    International Nuclear Information System (INIS)

    Kim Kyuhan; Jang Sunkyung; Tanaka, Tsuyoshi; Nagao, Keisuke

    1999-01-01

    Temporal geochemical and isotopical variations in the Ulreundgo alkali volcanic rocks provide important constraints on the origin and evolution of the volcanic rocks in relation to backarc basin tectonism. We determined the K-Ar ages, major and trace element contents, and Nd and Sr isotopic rations of the alkali volcanic rocks. The activities of Ulreungdo volcanoes can be divided, on the basis of radiometric ages and field occurrences, into five stages, though their activities range from 1.4 Ma to 0.01 Ma with short volcanic hiatus (ca. 0.05-0.3 Ma). The Nd-Sr isotopic data for Ulreungdo volcanic rocks enable us to conclude that: (1) the source materials of Ulreungdo volcanics are isotopically heterogeneous in composition, which is explained by the mixing of mantle derived magma and continental crustal source rocks. There is no systematic isotopic variations with eruption stages. Particularly, some volcanic rocks of stage 2 and 3 have extremely wide initial 87 Sr/ 86 Sr isotopic variations ranging from 0.7038 to 0.7092, which are influenced by seawater alterations; (2) the Ulreungdo volcanic rocks show EMI characteristic, while volcanic rocks from the Jejudo, Yeong-il and Jeon-gok areas have slightly depleted mantle source characteristics; (3) the trachyandesite of the latest eruption stage was originated from the mantle source materials which differ from other stages. A schematic isotopic evolution model for alkali basaltic magma is presented in the Ulreungdo volcanic island of the backarc basin of Japanese island arc system. (author)

  5. 3He/4He ratio, noble gas abundance and K-Ar dating of diamonds - an attempt to search for the records of early terrestrial history

    International Nuclear Information System (INIS)

    Ozima, M.; Zashu, S.; Nitoh, O.

    1983-01-01

    The 3 He/ 4 He ratios measured in 27 Southern Africa diamond stones, four from Premier Mine and the rest of unidentified origin, range from 4.2 x 10 -8 to 3.2 x 10 -4 , with three stones above 1 x 10 -4 . We conclude that the initial helium isotopic ratio ( 3 He/ 4 He) 0 in the earth was significantly higher than that of the planetary helium-A ( 3 He/ 4 He = 1.42 x 10 -4 ), but close to the solar helium ( 3 He/ 4 He = approx. 4 x 10 -4 ). The apparent K-Ar ages for the twelve diamonds of unidentified origin show enormously old age, indicating excess argon-40. 3 He/ 4 He evolution in diamonds suggests that the diamonds with the high 3 He/ 4 He ratio (> 2 x 10 -4 ) may be as old as the earth. Noble gas elemental abundance in the diamonds relative to the air noble gas abundance shows monotonic decrease with a decreasing mass number. This paper discusses the implications of these observations on the early solar system and the origin of diamonds. (author)

  6. Chemical, petrographic, and K-Ar age data to accompany reconnaissance geologic strip map from Kingman to south of Bill Williams Mountain, Arizona

    International Nuclear Information System (INIS)

    Arney, B.; Goff, F.; Eddy, A.C.

    1985-04-01

    As part of a reconnaissance mapping project, 40 chemical analyses and 13 potassium-argon age dates were obtained for Tertiary volcanic and Precambrian granitic rocks between Kingman and Bill Williams Mountain, Arizona. The dated volcanic rocks range in age from 5.5 +- 0.2 Myr for basalt in the East Juniper Mountains to about 25 Myr for a biotite-pyroxene andesite. The date for Picacho Butte, a rhyodacite in the Mt. Floyd volcanic field, was 9.8 +- 0.07 Myr, making it the oldest rhyodacite dome in that volcanic field. Dated rocks in the Fort Rock area range from 20.7 to 24.3 Myr. No ages were obtained on the Precambrian rocks. Compositionally, the volcanic rocks analyzed range from alkali basalt to rhyolite, but many rocks on the western side of the map area are unusually potassic. The granites chosen for analysis include syenogranite from the Hualapai Mountains, a muscovite granite from the Picacho Butte area, and two other granites. The chemical and K-Ar age data and petrographic descriptions included in this report accompany the reconnaissance geologic strip map published as LA-9202-MAP by Goff, Eddy, and Arney. 9 refs., 4 figs., 2 tabs

  7. Augsnes un zemes kvalitātes novērtējuma karšu digitizēšana

    OpenAIRE

    Stalīdzāns, Didzis

    2014-01-01

    Maģistra darba mērķis ir nodrošināt augšņu agroķīmiskās izpētes izstrādes procesa kartogrāfiskā materiāla lietošanas efektivitātes pieaugumu. Maģistra darbā tiek aprakstīts līdzšinējais augšņu agroķīmiskās izstrādes process Valsts augu aizsardzības dienestā un digitālo augšņu karšu izmantošanas iespējas. Pamatojoties uz darbā veiktās izpētes rezultātiem ir definēta problēma: augšņu agroķīmiskās kartes nav pieejamas telpisko datu formātā. Problēmas risinājumam tiek piedāvātas projekta alternat...

  8. U-Pb and K-Ar geochronology from the Cerro Empexa Formation, 1st and 2nd Regions, Precordillera, northern Chile

    International Nuclear Information System (INIS)

    Tomlinson, A.J; Martin, M.W; Blanco, N.; Perez de Arce, C

    2001-01-01

    The Cerro Empexa Formation (Galli, 1957) is a regionally distributed andesitic volcanic and continental sedimentary unit exposed in the Precordillera of the 1st and 2nd Regions of northern Chile. The formation has generally been considered to lie within the Lower or 'mid' Cretaceous, however, this assignment is based on scant, unreliable geochronologic data. Furthermore, there are conflicting interpretations as to whether the unit predates or postdates the first major Mesozoic shortening event affecting northern Chile. Because of the formation's presumed mid-Cretaceous age and its stratigraphic position over older back-arc sedimentary successions, the unit has been interpreted to represent products of the first eastward jump in the Andean magmatic arc from the arc's initial position in the Cordillera de la Costa (Scheuber and Reutter, 1992). In this paper we present the results of mapping and field observations that indicate exposures previously assigned to the Cerro Empexa Formation include two andesitic volcanic units separated by a major unconformity. The Cerro Empexa Formation proper lies above this unconformity. We also present U-Pb zircon and K-Ar geochronology that indicate the Cerro Empexa Formation is latest Cretaceous in its lower levels, and integrate our data with previously reported 40 Ar/ 39 Ar and fission-track data in the Cerros de Montecristo area (Maksaev, 1990; Maksaev and Zentilli, 1999) to show that 1800±600 m of rocks were deposited within ca. 2.5 m.y (au)

  9. Citation and quantitative analysis for articles of scientific- research journal of “SALAMAT KAR- E- IRAN”, Tehran University of Medical Sciences

    Directory of Open Access Journals (Sweden)

    A.A. Farshad

    2011-12-01

    Full Text Available Background and aimsNowadays study on journals is a common work. Thus, for the first time scientific- research journal of “SALAMAT KAR- E- IRAN” has considered to be study.MethodsImportant qualitative indices in studying articles were selected at first (such as distribution of study type, number of studies and balance between subjects, then based on original documents of all volumes, they were analyzed (by Microsoft Excel 2010 software and results were calculated via descriptive statistics methods. ResultsResults from survey and evaluation of 12 published volumes (106 articles showed that the majority of articles were about ergonomics and safety issues. However, in some other subjects there was no article at all. Majority of them have cited the English references. Consensus was a method that has used more than the other sampling methods. Research articles conducted by Male authors were five times more than articles written by females and; Total team corporation coefficient was calculated to be 0.62. Conclusion it was concluded that there was no proper distribution between subjects of articles. English references have cited more than Persian references because of a lack in Persian references or infirmity of a comprehensive indexing system. Considering the methodological point of view the majority of studies were of observational. However, interventional and high level studies can be performed in this field, conditions and facilities must be provided in order to achieve a higher quality and quantity of studies.

  10. K-Ar and Ar-Ar dating of the Palaeozoic metamorphic complex from the Mid-Bosnian Schist Mts., Central Dinarides, Bosnia and Hercegovina

    International Nuclear Information System (INIS)

    Pamic, J.; Balogh, K.; Hrvatovic, H.; Balen, D.; Palinkas, L.; Jurkovic, I.

    2004-01-01

    K-Ar and Ar-Ar whole rock and mineral ages are presented for 25 samples of metamorphic rocks from the Mid-Bosnian Schist Mts., representing one of the largest allochthonous Palaeozoic terranes incorporated within the Internal Dinarides. Four main age groups can be distinguished: 1) Variscan (∼ 343 Ma), 2) post-Variscan (288-238 Ma), 3) Early Cretaceous (mainly 121-92 Ma), and 4) Eocene (59--35 Ma) ages. Apart from this, an Oligocene (31 Ma) age was obtained on Alpine vein hyalophane. The radiometric dating indicates a polyphase metamorphic evolution of the Palaeozoic formations and suggests a pre-Carboniferous age of the volcano-sedimentary protoliths, an Early Carboniferous age of Variscan metamorphism and deformation, post-Variscan volcanism, an Early Cretaceous metamorphic overprint related to out-of-sequence thrusting of the Palaeozoic complex, and an Eocene and Oligocene metamorphic overprint related to the main Alpine compressional deformation and subsequent strike-slip faulting, and uplift of the metamorphic core. Accordingly, the Mid-Bosnian Schist Mts. can be correlated in its multistage geodynamic evolution with some Palaeozoic tectonostratigraphic units from the Austroalpine domain in the Eastern Alps. (author)

  11. Upper Triassic mafic dykes of Lake Nyos, Cameroon (West Africa) I: K-Ar age evidence within the context of Cameroon Line magmatism, and the tectonic significance

    Science.gov (United States)

    Aka, Festus Tongwa; Hasegawa, Takeshi; Nche, Linus Anye; Asaah, Asobo Nkengmatia Elvis; Mimba, Mumbfu Ernestine; Teitchou, Isidore; Ngwa, Caroline; Miyabuchi, Yasuo; Kobayashi, Tetsuo; Kankeu, Boniface; Yokoyama, Tetsuya; Tanyileke, Gregory; Ohba, Takeshi; Hell, Joseph Victor; Kusakabe, Minoru

    2018-05-01

    The hydrodynamic fragmentation that formed Lake Nyos in northwest Cameroon did not only make it the most unpopular lake in the world from a gas disaster perspective, it also opened a rare and formidable window through which much of the geology of Cameroon can be studied in a single locality. The Cambrian quartz monzonite cliff excavated by the maar-forming explosion and exposed in its northeastern shore is intruded by mafic dykes, two of which we dated. Even though close to one another, the dykes are different in composition. The alkaline dyke yields a slightly older (Carnian) K-Ar fedspar age of 231.1 ± 4.8 Ma, while the sub alkaline dyke yields an age of 224.8 ± 4.7 Ma (Norian). Based on radioisotopic age data available over the last 48 years (347 data) for the Cameroon Line magmatism comprising eruptives and volcano-plutonic complexes, the Nyos dykes are way older than the Cameroon Line, and even pre-date the Lower Cretaceous initiation of west Gondwana fragmentation in Equatorial Atlantic domain. They would therefore not have been directly linked to the formation of the Cameroon Line. Alternatively, they might be associated with the development of intra-continental rift systems in West Central Africa that pre-dated west Gondwana breakup to form the Atlantic Ocean.

  12. Anticonvulsant effect of AMP by direct activation of adenosine A1 receptor.

    Science.gov (United States)

    Muzzi, Mirko; Coppi, Elisabetta; Pugliese, Anna Maria; Chiarugi, Alberto

    2013-12-01

    Purinergic neurotransmission mediated by adenosine (Ado) type 1 receptors (A1Rs) plays pivotal roles in negative modulation of epileptic seizures, and Ado is thought to be a key endogenous anticonvulsant. Recent evidence, however, indicates that AMP, the metabolic precursor of Ado, also activate A1Rs. Here, we evaluated the antiepileptic effects of AMP adopting in vitro and in vivo models of epilepsy. We report that AMP reversed the increase in population spike (PS) amplitude and the decrease in PS latency induced by a Mg(2+)-free extracellular solution in CA1 neurons of mouse hippocampal slices. The AMP effects were inhibited by the A1R antagonist DPCPX, but not prevented by inhibiting conversion of AMP into Ado, indicating that AMP inhibited per se sustained hippocampal excitatory neurotransmission by directly activating A1Rs. AMP also reduced seizure severity and mortality in a model of audiogenic convulsion. Of note, the anticonvulsant effects of AMP were potentiated by preventing its conversion into Ado and inhibited by DPCPX. When tested in a model of kainate-induced seizure, AMP prolonged latency of convulsions but had no effects on seizure severity and mortality. Data provide the first evidence that AMP is an endogenous anticonvulsant acting at A1Rs. © 2013.

  13. Vitamin E-Mediated Modulation of Glutamate Receptor Expression in an Oxidative Stress Model of Neural Cells Derived from Embryonic Stem Cell Cultures

    Directory of Open Access Journals (Sweden)

    Afifah Abd Jalil

    2017-01-01

    Full Text Available Glutamate is the primary excitatory neurotransmitter in the central nervous system. Excessive concentrations of glutamate in the brain can be excitotoxic and cause oxidative stress, which is associated with Alzheimer’s disease. In the present study, the effects of vitamin E in the form of tocotrienol-rich fraction (TRF and alpha-tocopherol (α-TCP in modulating the glutamate receptor and neuron injury markers in an in vitro model of oxidative stress in neural-derived embryonic stem (ES cell cultures were elucidated. A transgenic mouse ES cell line (46C was differentiated into a neural lineage in vitro via induction with retinoic acid. These cells were then subjected to oxidative stress with a significantly high concentration of glutamate. Measurement of reactive oxygen species (ROS was performed after inducing glutamate excitotoxicity, and recovery from this toxicity in response to vitamin E was determined. The gene expression levels of glutamate receptors and neuron-specific enolase were elucidated using real-time PCR. The results reveal that neural cells derived from 46C cells and subjected to oxidative stress exhibit downregulation of NMDA, kainate receptor, and NSE after posttreatment with different concentrations of TRF and α-TCP, a sign of neurorecovery. Treatment of either TRF or α-TCP reduced the levels of ROS in neural cells subjected to glutamate-induced oxidative stress; these results indicated that vitamin E is a potent antioxidant.

  14. PRM1 and KAR5 function in cell-cell fusion and karyogamy to drive distinct bisexual and unisexual cycles in the Cryptococcus pathogenic species complex.

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    Ci Fu

    2017-11-01

    Full Text Available Sexual reproduction is critical for successful evolution of eukaryotic organisms in adaptation to changing environments. In the opportunistic human fungal pathogens, the Cryptococcus pathogenic species complex, C. neoformans primarily undergoes bisexual reproduction, while C. deneoformans undergoes both unisexual and bisexual reproduction. During both unisexual and bisexual cycles, a common set of genetic circuits regulates a yeast-to-hyphal morphological transition, that produces either monokaryotic or dikaryotic hyphae. As such, both the unisexual and bisexual cycles can generate genotypic and phenotypic diversity de novo. Despite the similarities between these two cycles, genetic and morphological differences exist, such as the absence of an opposite mating-type partner and monokaryotic instead of dikaryotic hyphae during C. deneoformans unisexual cycle. To better understand the similarities and differences between these modes of sexual reproduction, we focused on two cellular processes involved in sexual reproduction: cell-cell fusion and karyogamy. We identified orthologs of the plasma membrane fusion protein Prm1 and the nuclear membrane fusion protein Kar5 in both Cryptococcus species, and demonstrated their conserved roles in cell fusion and karyogamy during C. deneoformans α-α unisexual reproduction and C. deneoformans and C. neoformans a-α bisexual reproduction. Notably, karyogamy occurs inside the basidum during bisexual reproduction in C. neoformans, but often occurs earlier following cell fusion during bisexual reproduction in C. deneoformans. Characterization of these two genes also showed that cell fusion is dispensable for solo unisexual reproduction in C. deneoformans. The blastospores produced along hyphae during C. deneoformans unisexual reproduction are diploid, suggesting that diploidization occurs early during hyphal development, possibly through either an endoreplication pathway or cell fusion-independent karyogamy

  15. Rb-Sr and K-Ar age of globular phyllosilicates and biostratigraphy of the Riphean deposits of the Olenek Uplift (North Siberia)

    Science.gov (United States)

    Zaitseva, T. S.; Gorokhov, I. M.; Semikhatov, M. A.; Ivanovskaya, T. A.; Kuznetsov, A. B.; Dorzhieva, O. V.

    2017-11-01

    This work presents results of the complex mineralogical, geochemical, and isotope-geochronological investigation of globular dioctahedral 2: 1 phyllosilicates (GPS) of the illite-glauconite series from the Riphean sequences of the Olenek Uplift. It is established that GPS (glauconite, Al-glauconite, Fe-illite) in deposits of the Arymass, Debengda, and Khaipakh formations are represented by mixed-layer varieties of two types: (1) with relatively low (cell of minerals varies from 9.18 to 9.72 Å. The Rb-Sr age dating of GPS was first carried out in combination with the calculation of theoretical pattern of the cation distribution in the mineral structure and comparison of the calculation results obtained with the Mössbauer and IR spectroscopy data. This approach is based on the assumption that development and evolution of isotope systems in GPS are synchronous with the evolution of the crystalline structure of the mineral at various stages of the geological and geochemical history of the development of sedimentary units. Analysis of the obtained data allows us to state that the structural features of the Riphean GPS from the Olenek section reflect the early diagenetic stages of the formation of the minerals studied. The 87Sr/86Sr initial ratios in the studied sediments are consistent with the range of variations in this ratio in the Middle Riphean Ocean (0.7049-0.7061). The Rb-Sr and K-Ar ages of the GPS of the Arymass (1305 ± 8 and 1302 Ma, respectively), Debengda (1265 ± 12 and 1284 ± 22 Ma), and Khaipakh (1172 ± 18 and 1112 ± 24 Ma) formations in the Olenek Uplift section are close to the accumulation time of corresponding deposits and, correspondingly, have significance for stratigraphic correlations.

  16. 40Ar/ 39Ar, K-Ar and 230Th- 238U dating of the Laschamp excursion: A radioisotopic tie-point for ice core and climate chronologies

    Science.gov (United States)

    Singer, Brad S.; Guillou, Hervé; Jicha, Brian R.; Laj, Carlo; Kissel, Catherine; Beard, Brian L.; Johnson, Clark M.

    2009-08-01

    A brief period of enhanced 10Be flux that straddles the interstadial warm period known as Dansgaard-Oeschger event 10 in Greenland and its counterpart in Antarctica, the Antarctic Isotope Maximum 10 is but one consequence of the weakening of Earth's magnetic field associated with the Laschamp excursion. This 10Be peak measured in the GRIP ice core is dated at 41,250 y b2k (= before year 2000 AD) in the most recent GICC05 age model obtained from the NorthGRIP core via multi-parameter counting of annual layers. Uncertainty in the age of the 10Be peak is, however, no better than ± 1630 y at the 95% confidence level, reflecting accumulated error in identifying annual layers. The age of the Laschamp excursion [Guillou, H., Singer, B.S., Laj, C., Kissel, C., Scaillet, S., Jicha, B., 2004. On the age of the Laschamp geomagnetic excursion. Earth Planet. Sci. Lett. 227, 331-343.] is revised on the basis of new 40Ar/ 39Ar, unspiked K-Ar and 238U- 230Th data from three lava flows in the Massif Central, France, together with the 40Ar/ 39Ar age of a transitionally magnetized lava flow at Auckland, New Zealand. Combined, these data yield an age of 40,700 ± 950 y b2k, where the uncertainty includes both analytical and systematic ( 40K and 230Th decay constant) errors. Taking the radioisotopic age as a calibration tie point suggests that the layer-counting chronologies for the NorthGRIP and GISP2 ice cores are more accurate and precise than previously thought at depths corresponding to the Laschamp excursion.

  17. Nd and Sr isotopes and K-Ar ages of the Ulreungdo alkali volcanic rocks in the East Sea, South Korea

    Energy Technology Data Exchange (ETDEWEB)

    Kim Kyuhan; Jang Sunkyung [Ewha Womans Univ., Seoul (Korea); Tanaka, Tsuyoshi; Nagao, Keisuke

    1999-07-01

    Temporal geochemical and isotopical variations in the Ulreundgo alkali volcanic rocks provide important constraints on the origin and evolution of the volcanic rocks in relation to backarc basin tectonism. We determined the K-Ar ages, major and trace element contents, and Nd and Sr isotopic rations of the alkali volcanic rocks. The activities of Ulreungdo volcanoes can be divided, on the basis of radiometric ages and field occurrences, into five stages, though their activities range from 1.4 Ma to 0.01 Ma with short volcanic hiatus (ca. 0.05-0.3 Ma). The Nd-Sr isotopic data for Ulreungdo volcanic rocks enable us to conclude that: (1) the source materials of Ulreungdo volcanics are isotopically heterogeneous in composition, which is explained by the mixing of mantle derived magma and continental crustal source rocks. There is no systematic isotopic variations with eruption stages. Particularly, some volcanic rocks of stage 2 and 3 have extremely wide initial {sup 87}Sr/{sup 86}Sr isotopic variations ranging from 0.7038 to 0.7092, which are influenced by seawater alterations; (2) the Ulreungdo volcanic rocks show EMI characteristic, while volcanic rocks from the Jejudo, Yeong-il and Jeon-gok areas have slightly depleted mantle source characteristics; (3) the trachyandesite of the latest eruption stage was originated from the mantle source materials which differ from other stages. A schematic isotopic evolution model for alkali basaltic magma is presented in the Ulreungdo volcanic island of the backarc basin of Japanese island arc system. (author)

  18. Bidirectional modulation of hippocampal gamma (20-80 Hz) frequency activity in vitro via alpha(α)- and beta(β)-adrenergic receptors (AR).

    Science.gov (United States)

    Haggerty, D C; Glykos, V; Adams, N E; Lebeau, F E N

    2013-12-03

    Noradrenaline (NA) in the hippocampus plays an important role in memory function and has been shown to modulate different forms of synaptic plasticity. Oscillations in the gamma frequency (20-80 Hz) band in the hippocampus have also been proposed to play an important role in memory functions and, evidence from both in vitro and in vivo studies, has suggested this activity can be modulated by NA. However, the role of different NA receptor subtypes in the modulation of gamma frequency activity has not been fully elucidated. We have found that NA (30 μM) exerts a bidirectional control on the magnitude of kainate-evoked (50-200 nM) gamma frequency oscillations in the cornu Ammonis (CA3) region of the rat hippocampus in vitro via activation of different receptor subtypes. Activation of alpha-adrenergic receptors (α-AR) reduced the power of the gamma frequency oscillation. In contrast, activation of beta-adrenergic receptors (β-AR) caused an increase in the power of the gamma frequency oscillations. Using specific agonists and antagonists of AR receptor subtypes we demonstrated that these effects are mediated specifically via α1A-AR and β1-AR subtypes. NA activated both receptor subtypes, but the α1A-AR-mediated effect predominated, resulting in a reversible suppression of gamma frequency activity. These results suggest that NA is able to differentially modulate on-going gamma frequency oscillatory activity that could result in either increased or decreased information flow through the hippocampus. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Germination induction of dormant Avena fatua caryopses by KAR(1) and GA(3) involving the control of reactive oxygen species (H2O2 and O2(·-)) and enzymatic antioxidants (superoxide dismutase and catalase) both in the embryo and the aleurone layers.

    Science.gov (United States)

    Cembrowska-Lech, Danuta; Koprowski, Marek; Kępczyński, Jan

    2015-03-15

    Avena fatua L. caryopses did not germinate at 20 °C in darkness because they were dormant. However, they were able to germinate in the presence of karrikinolide (KAR1), a key bioactive compound present in smoke, and also in the presence of gibberellin A3 (GA3), a commonly known stimulator of seed germination. The aim of this study was to collect information on a possible relationship between the above regulators and abscisic acid (ABA), reactive oxygen species (ROS) and ROS scavenging antioxidants in the regulation of dormant caryopses germination. KAR1 and GA3 caused complete germination of dormant A. fatua caryopses. Hydrogen peroxide (H2O2), compounds generating the superoxide (O2(·-)), i.e. menadione (MN), methylviologen (MV) and an inhibitor of catalase activity, aminotriazole (AT), induced germination of dormant caryopses. KAR1, GA3, H2O2 and AT decreased ABA content in embryos. Furthermore, KAR1, GA3, H2O2, MN, MV and AT increased α-amylase activity in caryopses. The effect of KAR1 and GA3 on ROS (H2O2, O2(·-)) and activities of the superoxide dismutase (SOD) and catalase (CAT) were determined in caryopses, embryos and aleurone layers. SOD was represented by four isoforms and catalase by one. In situ localization of ROS showed that the effect of KAR1 and GA3 was associated with the localization of hydrogen peroxide mainly on the coleorhiza. However, the superoxide was mainly localized on the surface of the scutellum. Superoxide was also detected in the protruding radicle. Germination induction of dormant caryopses by KAR1 and GA3 was related to an increasing content of H2O2, O2(·-)and activities of SOD and CAT in embryos, thus ROS homeostasis was probably required for the germination of dormant caryopses. The above regulators increased the content of ROS in aleurone layers and decreased the activities of SOD and CAT, probably leading to the programmed cell death. The presented data provide new insights into the germination induction of A. fatua dormant

  20. Antik Yunan Dönemi Karşılaştırmalı Siyaset Biliminde Siyasal Sistem Sınıflandırmalarına Genel bir Bakış

    Directory of Open Access Journals (Sweden)

    Nihat YILMAZ

    2014-01-01

    Full Text Available Siyaset Biliminin bir alt disiplini olarak karşılaştırmalı siyaset biliminin popülaritesi günümüzde gittikçe artmaktadır. Bu disiplin, farklı ülkelerin siyasal sistemleri hakkında detaylı bilgiler vermesinden dolayı fazlaca önemsenmektedir. Günümüzde ilginin giderek arttığı böyle bir alanın tarihsel geçmişi ise oldukça eski dönemlere dayanmaktadır. karşılaştırmalı siyaset bilimi alanında yapılan ilk siyasal sistem sınıflandırmaları Antik Yunan döneminde ortaya çıkmıştır. Bundan dolayı bu makalede, batı siyasal düşüncesi içerisinde yer alan Antik Yunan dönemindeki siyasal sistem sınıflandırmalarının bazı düşünürler bağlamında incelenmesi amaçlanmaktadır. Makalede, öncelikle temel kavramlar olan karşılaştırmalı siyaset bilimi ve siyasal sistem kavramlarına değinilmekte ve daha sonra Antik Yunan dönemi siyasal sistem sınıflandırmaları Heredotos, Platon ve Aristoteles örnekleri ile incelenmektedir.

  1. Dating low-grade metamorphism and deformation of the Espinhaço Supergroup in the Chapada Diamantina (Bahia, NE Brazil: a K/Ar fine-fraction study

    Directory of Open Access Journals (Sweden)

    Annette Süssenberger

    Full Text Available This study focuses on the northernmost part of the Mesoproterozoic Espinhaço Supergroup that crops out in the Chapada Diamantina. The fine-fraction K/Ar dating obtained on slightly metamorphosed sediments of the siliciclastic Espinhaço Supergroup shows a polyphase deformation history that corresponds to the Brasiliano (Pan-African orogenic cycle. The isotopic results are interpreted to indicate three age domains coincident with three structurally different domains. Constrained by the Kübler Index ('illite crystallinity' and illite polytypism, the thermal conditions generated during the tectonic activity show a gradual trend from the craton margins to the interior from epizonal to diagenetic. The northern Chapada Diamantina is situated in the foreland of the Riacho do Pontal belt and comprises the sediments of the Espinhaço Supergroup northeast of the Irecê basin. The K/Ar ages for < 2 µm illite fractions range between 645 and 621 Ma [mean 637±9 Ma (2s] and for < 0.2 µm fraction range between 625 and 603 Ma [mean 614±9 Ma (2s]. Samples from the central Chapada Diamantina east of the Irecê basin are not affected by a Brasiliano deformation event and therefore, the N-S-trending structures are assumed to be older. The deformation of the southern Chapada Diamantina was established in conjunction with the formation of the Araçuai orogenesis and the inversion and reactivation of the Paramirim impactogen. The last stage of deformation in this area is recorded by the K/Ar fine-fraction dating between 470 and 460 Ma.

  2. Cooling age of the Birimian juvenile crust in West Africa. U-Pb, Rb-Sr and K-Ar data on the 2.1 Ga granite-greenstone terrains from SW-Niger

    International Nuclear Information System (INIS)

    Lama, C.; Dautel, D.; Zimmermann, J.L.; Cheilletz, A.; Pons, J.

    1994-01-01

    A comparison between zircon U-Pb, whole-rock Rb-Sr and biotite-amphibole K-Ar data on Birimian granite-greenstone terrains from SW-Niger indicates that the youngest granitic plutons were emplaced at 2.115 ± 5 Ma and that both the plutons and the surrounding greenstones yield cooling ages around 2.118 Ma. The age similarity between the end of the plutonism and the cooling of plutons and surrounding greenstone further suggests rapid cooling at the end of the plutonic event and, thus, corroborates a model of greenstone metamorphism linked to the thermal effect of the plutons. (authors)

  3. The LDL receptor.

    Science.gov (United States)

    Goldstein, Joseph L; Brown, Michael S

    2009-04-01

    In this article, the history of the LDL receptor is recounted by its codiscoverers. Their early work on the LDL receptor explained a genetic cause of heart attacks and led to new ways of thinking about cholesterol metabolism. The LDL receptor discovery also introduced three general concepts to cell biology: receptor-mediated endocytosis, receptor recycling, and feedback regulation of receptors. The latter concept provides the mechanism by which statins selectively lower plasma LDL, reducing heart attacks and prolonging life.

  4. Isotopegeochemical investigations and dating on minerals and fossils from sedimentary rocks: 1. Glauconites from Jura, Molasse and Helveticum (K-Ar, Rb-Sr), 2. 87Sr/86Sr-Isotope stratigraphy on marine and limnetic micro- and macro-fossils, 3. Primary minerals from tertiary bentonites and tuffs (U-Pb, K-Ar)

    International Nuclear Information System (INIS)

    Fischer, H.

    1988-01-01

    Glauconite investigations: the main problem in dating glauconites lies in the identification of authigenic minerals which have not been influenced by post-sedimentary processes. The age determination on glauconites from the three different tectonic units: the Jura mountains, the molasse basin and the Helvetic nappes, yield inconsistent results. Up to 35% too young K-Ar ''ages'' of glauconites from limestones from the Helvetic nappes can be traced to partial Ar loss caused by sediment-lithification and tectonic events. Sr-isotope stratigraphy: multiple analyses of recent samples from the Mediterranean Sea and from the North Atlantic show that the 87 Sr/ 86 Sr isotope ratios correspond well. In a stratigraphic ideal section from the Upper marine molasse a resolution of 206 Pb/ 238 U method zircons from the Fish Canyon Tuff were measured and yielded ages of 28.49±0.10, 24.46±0.11 and 28.46±0.13 Ma. These values correspond well with the published mean value of zircon and apatite fission track age of 28.4±0.7 Ma. Thus, the U-Pb method for dating young volcanic minerals seems to be suitable. However, the published mean value (''solid state age'') of Naeser et al. (1981) is higher than the published (''gas age'') mean value of 27.2±0.7 Ma based on biotite, sanidine, hornblende and plagioclase. (author) figs., tabs., refs

  5. Amaç ve Beklenti Karşısında Karşılaştırmalı Edebiyatın Tanı(MSal Krizine İlişkin Birtakım Tartışmalı Saptamalar Some Argumentative Determinations Regarding Diagnostic/Definitional Crisis Of Comparative Literature In Terms Of Accordance With Its Purpose And Expectation

    Directory of Open Access Journals (Sweden)

    Abdulhakim TUĞLUK

    2013-09-01

    Full Text Available Comparison which possesses the characteristics of critic in linewith its purposes and ambitions keeps on its actuality and differenceperception because of its argumentative position within the science ofliterature. “Comparative Literature Science” which has become effectivein literature argumentations in recent years in Turkey has not beenable to make its identity and conceptual entity acceptable, yet. Not onlythe uncertainties in the definition, but also some problems in practicekeep the questions against comparative literature in a certain level.There are also some uncertainties whether it is a method or a science initself as well as the acceptability of it by national men of literature.Comparison, which is seen as easy to do at first in terms of feasibility,shows itself as a complex process when the literal and aestheticmissions attributed by the concept to it are taken into consideration.This complexity becomes a crisis in which there are many questionswhen it is faced with diagnostic and definitive problems. On the otherhand, West-centered perception of the comparative literature and itsinternational face embracing the concept of „world literature‟(Weltliteratur make global scale expectations committed by the conceptmore argumentative rather than meeting these expectations. In thisstudy, the main starting point is gaining a certain point of view to theidentity confusion of comparative literature and establishing a generalargumentation basis. The purpose of this study is revealing somecomplex points in theory and practice considering existential problemsof comparative literature and bringing some expansion to somehandicaps regarding essence of the comparative literature. Amaç ve hedefleri doğrultusunda bir eleştiri türü niteliği taşıyan karşılaştırma, edebiyat bilimi içerisindeki tartışmalı konumu nedeniyle güncelliğini ve farklılık algısını sürdürmektedir. Türkiye‟de, son yıllarda, edebi tart

  6. Karacaların (C. capreolus Av Değerlerinin Farklı Sistemlerce Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Milan Urošević

    2017-03-01

    Full Text Available Bu çalışma, avlanan karacaların değerkendirilmesindeki en iyi metodun belirlenmesi amacıyla gerçekleştirilmiştir. Bu amaçla, Sırbistan av sahasında 2009-2010 yıllarında avlanmış 192 karacanın av formları kullanılmıştır. Avlanan hayvanların boynuz kütleleri ile CIC (Uluslararası Av ve Yaban Hayatı Koruma Konseyi değeri arasındaki korelasyon kadar boynuzun kütlesi ve hacmi arasındaki korelasyon ile bu iki değişkenin boynuzların ortalama uzunlukları ve boynuz estetik unsurlarının boynuz değerinin tespitinde iyi bir belirteç olup olmadığı da araştırıldı. Mümkün olduğu durumlarda, avcı için hangi modelin daha avantajlı olduğunun belirlenmesi için eski ve yeni sisteme göre boynuzun ticari değeri ile aynı boynuzun bu iki sisteme göre maliyet-fiyat karşılaştırması da yapıldı. Sonuçlar, boynuzun kütlesinin değerlendilidiği çoğu durumda, CIC sistemindeki boynuz hacim puanlarına göre değerlendirilmesinin iyi bir indikatör olduğunu göstermiştir. Böylece, karaca boynuzlarının değerini belirleyen hacmi ve diğer belirleyicileri arasında, ağırlığa oranla daha güçlü korelasyon olduğundan, avcılık esnasında, boynuzların büyüklüğüne odaklanılması gerektiği söylenebilir.

  7. K-Ar dating of fluid flow and fault movement in clay rich gouge: an example from the northern Sydney Basis

    International Nuclear Information System (INIS)

    Zwingmann, H.; Wilson, T.; Offler, R.

    1999-01-01

    Full text: The occurrence of synkinematic and authigenic clay minerals, in particular illite, is a common feature in fault gouges. Until recently very few attempts have been made to date fault gouges. We present preliminary age data for synkinematic illite growth in two fault zones of the northern Sydney Basin. This study represents the first of its kind in Australia. Eleven samples were selected for this study from two faults situated at Burwood Beach within the northern Sydney Basin. The faults are subparallel, approximately 1.5m apart and trend N-S with steep easterly dips. A total displacement of 10m is observed on the western fault, whilst 3m of vertical displacement has occurred on the eastern fault. 1cm wide foliated gouge zones are developed along both fault surfaces that represent the regions in which principal displacement has occurred. Samples were collected from the gouge zones and host siltstones and tuffs within and outside the damage zone originating from the Lambton Subgroup of the Newcastle Coal Measures. They were disaggregated using a repetitive freeze-thaw technique to separate 38 Ar spike. XRD analyses of samples indicate that illite/smectite (I/S) and kaolinite in varying proportions are present in the fractions from the fault gouges and host rocks in the damage zone. In most samples, the I/S contains 70-90% illite, suggesting temperatures 40 Ar ranges for these samples range between 59.28 to 98.1% indicating negligible atmospheric Ar contamination. The reliability of the ages is also confirmed by the agreement within 2s analytical limits for the duplicate analyses of the <2mm fraction of some samples. The 272-281 Ma K-Ar dates obtained from the 2-6mm fractions of the host rocks at Burwood Beach are older than the age of the sequence in which the samples occur (245-252 Ma; Roberts et al., 1996). This suggests that detrital mica is present in these samples consistent with petrographic studies. The younger ages of 237-244.9 Ma are thought to

  8. Glutamatergic induction of CREB phosphorylation and Fos expression in primary cultures of the suprachiasmatic hypothalamus in vitro is mediated by co-ordinate activity of NMDA and non-NMDA receptors.

    Science.gov (United States)

    Schurov, I L; McNulty, S; Best, J D; Sloper, P J; Hastings, M H

    1999-01-01

    Exposure of Syrian hamsters to light 1 h after lights-off rapidly (10 min) induced nuclear immunoreactivity (-ir) to the phospho-Ser133 form of the Ca2+/cAMP response element (CRE) binding protein (pCREB) in the retinorecipient zone of the suprachiasmatic nuclei (SCN). Light also induced nuclear Fos-ir in the same region of the SCN after 1 h. The glutamatergic N-methyl-D-aspartate (NMDA) receptor blocker MK801 attenuated the photic induction of both factors. To investigate glutamatergic regulation of pCREB and Fos further, tissue blocks and primary cultures of neonatal hamster SCN were examined by Western blotting and immunocytochemistry in vitro. On Western blots of SCN tissue, the pCREB-ir signal at 45 kDa was enhanced by glutamate or a mixture of glutamatergic agonists (NMDA, amino-methyl proprionic acid (AMPA), and Kainate (KA)), whereas total CREB did not change. Glutamate or the mixture of agonists also induced a 56 kDa band identified as Fos protein in SCN tissue. In dissociated cultures of SCN, glutamate caused a rapid (15 min) induction of nuclear pCREB-ir and Fos-ir (after 60 min) exclusively in neurones, both GABA-ir and others. Treatment with NMDA alone had no effect on pCREB-ir. AMPA alone caused a slight increase in pCREB-ir. However, kainate alone or in combination with NMDA and AMPA induced nuclear pCREB-ir equal to that induced by glutamate. The effects of glutamate on pCREB-ir and Fos-ir were blocked by antagonists of both NMDA (MK801) and AMPA/KA (NBQX) receptors. In the absence of extracellular Mg2+, MK801 blocked glutamatergic induction of Fos-ir. However, the AMPA/KA receptor antagonist was no longer effective at blocking glutamatergic induction of either Fos-ir or pCREB-ir, consistent with the model that glutamate regulates gene expression in the SCN by a co-ordinate action through both NMDA and AMPA/KA receptors. Glutamatergic induction of nuclear pCREB-ir in GABA-ir neurones was blocked by KN-62 an inhibitor of Ca2+/Calmodulin (Ca

  9. Ipsilateral feeding-specific circuits between the nucleus accumbens shell and the lateral hypothalamus: regulation by glutamate and GABA receptor subtypes.

    Science.gov (United States)

    Urstadt, Kevin R; Kally, Peter; Zaidi, Sana F; Stanley, B Glenn

    2013-04-01

    The nucleus accumbens shell (AcbSh) and the lateral hypothalamus (LH) are both involved in the control of food intake. Activation of GABA(A) receptors or blockade of AMPA and kainate receptors within the AcbSh induces feeding, as does blockade of GABA(A) receptors or activation of NMDA receptors in the LH. Further, evidence suggests that feeding induced via the AcbSh can be suppressed by LH inhibition. However, it is unclear if this suppression is specific to feeding. Adult male Sprague-Dawley rats with 3 intracranial guide cannulas, one unilaterally into the AcbSh and two bilaterally into the LH, were used to explore this issue. DNQX (1.25 μg) or muscimol (100 ng) infused into the AcbSh unilaterally elicited feeding, and this elicited intake was suppressed by bilateral LH injection of d-AP5 (2 μg) or muscimol (25 ng). The effectiveness of d-AP5 or muscimol infusion into either the LH site ipsilateral or contralateral to the AcbSh injection was compared. Ipsilateral LH injection of d-AP5 or muscimol was significantly more effective than contralateral injection in suppressing food intake initiated by AcbSh injection of DNQX or muscimol. These results add to the prior evidence that inhibition of the LH through pharmacological modulation of NMDA or GABA(A) receptors specifically suppresses feeding initiated by AcbSh inhibition, and that these two regions communicate via an ipsilateral circuit to specifically regulate feeding. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Nostalgia Gone Bad / Karlis Streips

    Index Scriptorium Estoniae

    Streips, Karlis

    2011-01-01

    9. mai võidupüha tähistamisest. Autor leiab, et 9. mai ja 16. märtsil tähistatava leegionäride päeva üritusi ning pidustusi tuleks ignoreerida, kuna rahvas, kes on minevikus kinni, ei suuda mõelda olevikule ja tulevikule

  11. Sammas number kaks / Karli Luik

    Index Scriptorium Estoniae

    Luik, Karli, 1977-

    2011-01-01

    Eesti Kunstiakadeemia uue hoone arhitektuurikonkursi võidutöö "Art Plaza" (Taani arhitektuuribürood Sea ja Effekt) muudetud joonistest. Kadunud on hoonesisene avar avalik ruum ja alles on jäänud tihedad, sügavad, kitsaste pimedate koridoridega korrused

  12. Tanzimat Hareketleri Karşısında Aşık Seyrani Ashik Seyrânî Against Tanzimat (Reform Movements

    Directory of Open Access Journals (Sweden)

    Eyüp AKMAN

    2012-09-01

    ılları arasında yaşamıştır. Aslen Kayseri Develilidir. Hayatı boyunca üç padişah dönemi görmüştür. Bunlar III. Selim, II. Mahmut ve Abdülmecit dönemleridir. Özellikle son iki padişah dönemi, gençlik ve olgunluk dönemine rastlar. Seyrânî, II. Mahmut döneminde hız kazanan, Abdülmecit döneminde Tanzimat ve Islahat fermanlarıyla resmiyet kazanan yenileşme ve batılılaşama hareketlerine karşı halkın duygularına tercüman olmuş, toplumda gördüğü sosyal aksaklıkları ve çarpıklıkları padişahtan bile çekinmeden pervasızca dile getirmiştir. Seyrani, klasik edebiyatta hiciv, halk edebiyatında taşlama adını alan türde oldukça başarılıdır. Bu durum biraz da onun mizacıyla alakalıdır. İstanbul’a mesleğini icra etmek için gelen Seyrani, devrin her aşığı gibi saray aşıklarının arasına katılmayı arzu etmiştir. Fakat bu arzusu gerçekleşmemiştir. Bundan dolayı olsa gerek saray erkanını özellikle sadrazamları keskin bir dille hicvetmiştir. Seyrani’nin saraya karşı bu kadar sert tavır almasına başka bir sebep olarak da Yeniçeri teşkilatının kaldırılmasını gösterebiliriz. Bektaşiliğe meyilli olan Seyrani de diğer Bektaşi şairleri gibi bu teşkilatın kaldırılmasını kabullenememiş bundan dolayı saraya menfi tavır almıştır. Seyrani’nin şiirlerinde on dokuzuncu yüzyılın sosyal, ekonomik hayatını bulmak mümkündür. Özellikle Tanzimat ve Islahat hareketleri neticesinde ülkenin düştüğü durum, saray tarafından lüzumu olmaksızın yapılan sınırsız harcamalar, halkın yeniliklere ayak uyduramaması, bizzat padişahların bir batılı gibi davranması, kadıların rüşvet alarak adalet mekanizmasının çökmesi onun şiirlerinde hicvedilmiştir. Bu araştırmamızda Tanzimat hareketleri ve bunların halka nasıl yansıdığı Seyrânî’nin şiirlerinden hareketle anlatılacak ve dönem hakkında bazı değerlendirmelerde bulunulacaktır.

  13. Tempe Üretiminde Asetik ve Laktik Asit Ölçümleri İçin Kullanılan İki Metodun Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Günnur Tuncel

    2015-02-01

    Full Text Available Soya fasulyesinin ıslatma aşamasında fermantasyona uğraması tempenin daha kaliteli olmasına neden olmaktadır. Böyle bir fermantasyonda meydana gelen Laktik ve Asetik asit miktarlarının ölçülmesinde çeşitli yöntemler kullanılmaktadır. Araştırmada bu asitler tek olarak ve karıştırılarak HPLC ve Enzimatik yöntemle ölçülmüş ve sonuçlar karşılaştırılmıştır. HPLC yöntemi ile mevcut Laktik ve Asetik asit miktarlarının %40’ı belirlenebilmiş, enzimatik yöntemde ise bu %70’e kadar çıkmıştır.

  14. Preliminary study of geotectonic evolution of the southern region of Sao Francisco (MG, Brazil) craton: an interpretation based on Rb-Sr, K-Ar, Pb-Pb and fission track data

    International Nuclear Information System (INIS)

    Teixeira, W.; Fonseca, A.C.; Poupeau, G.; Padilha, A.V.; Zapparolli, L.H.; Kawashita, K.; Khoury, M.C.

    1985-01-01

    The results obtained from isotopic dating techniques (Rb-Sr, K-Ar, Pb-Pb and fission tracks) applied to samples from the southern region of Sao Francisco craton (Mg, Brazil) are discussed. Rb-Sr and Pb-Pb ages, in total rock, allowed the determination of crust enlargement, with eventual modifications of the pre-existing crust, during the Late Archean period (3000 to 2600 million years) and the Inferior Proterozoic period (2400 to 2100 m.y.). Three main cooling periods of time were determined by K-Ar dating of mica, amphiboles and total rock at the craton border: 2200 to 1700 m.y., 1300 to 1100 m.y. and 900 to 400 m.y. related, respectively, to superposition of three cycles: Transamazonico, Uruacuano and Brasiliano. Cooling below 110 0 C, detected by the fission track method applied to apatites, pointed out an age of 850 m.y. at the internal parts and 550 m.y. at the craton periphery, thus showing a progressive action of Brazilian marginal movable zones in the studied region. The application of these two techniques together enabled the evaluation of the rocks cooling shape. Cooling of these samples was complex between 2700 and 2200 m.y. and slow from 2000 m.y. onwards. The integrated treatment of data from the various dating techniques is of great importance to know the geotectonic evolution of ancient polycyclic sites. (C.L.B.) [pt

  15. U-Pb, Pb-Pb, and K-Ar isotopic study and petrography of uraniferous phosphate-bearing rocks in the Thelon Formation, Dubawnt Group, Northwest Territories, Canada

    International Nuclear Information System (INIS)

    Miller, A.R.; Cumming, G.L.; Krstic, D.

    1989-01-01

    The Thelon Formation, uppermost unit of the Dubawnt Group, overlies a regionally extensive paleoweathered zone developed on a wide range of lithochronological units including formations in the lower Dubawnt Group. Authigenic uraniferous phosphate minerals, fluorapatite and goyazite, cementing Thelon conglomerate - sandstone and filling fractures in the underlying paleoweathered zone, were dated in an attempt to better constrain the age of Thelon sedimentation and diagenesis. The oldest age, 1720 ± 6 Ma, derived from phosphate-cemented sediments, is interpreted as a minimum age for diagenesis and therefore brackets initial Thelon sedimentation between emplacement of fluorite-bearing granites at 1753 Ma and authigenic phosphate cementation at 1720 Ma. Additional ages of 1685 ± 4 and 1647 Ma are interpreted as remobilization or subsequent cementation events. K-Ar ages on illite, 1386 ± 37 and 1266 ± 31 Ma, from the paleoweathered zone and basal conglomerate, respectively, are significantly younger than ages derived from coexisting phosphate. These K-Ar ages recorded hydrothermal events that may be related to processes associated with unconformity-type uranium mineralization at approximately 1400-1300 Ma. Ages from the Thelon Basin permit geochronologic correlations with the Athabasca and Hornby basins, long correlated on the basis of similarities in sedimentation, stratigraphy, and tectonic setting

  16. Geotectonic structural interpretation of the basement complex at the eastern border of the Espinhaco ridge, in Guanhaes and Gouveia region, based on an integration of their U/Pb and K/Ar geochronology united

    International Nuclear Information System (INIS)

    Teixeira, W.; Salvador, E.D.; Siga Junior, O.; Sato, K.; Dossin, I.A.; Dossin, T.M.

    1990-01-01

    The basement complex at the eastern border of the Espinhaco ridge is composed of predominantly gneissic rocks which were subjected to migmatization and granitization. Overall the area shows complex tectonic evolution with recurrence of tectonomagmatic and metamorphic events as supported by geological, geochronological and structural studies. The Rb/Sr geochronology carried out on the basement rocks and metavolcanics from the Espinhaco interpreted together with the published U-Pb, Rb-Sr and K-Ar data defines the following scenario for the Precambrian crustal evolution. 1. Primary origin of a sialic crust at 2.97-2.84 Ga. ago as supported by U-Pb zircon ages. 2. Crustal reworking of the Archean crust and subordinate juvenile accretion from upper mantle during the 2.2-2.OGa. period, as suggested by the isochrons. 3. Recurrence of Middle Proterozoic events over the basement rocks (gneisses and charnockites) and metavolcanics of the Espinhaco as showed by isochrons. 4. Development of Late Proterozoic migmatization over the basement rocks (0.75 Ga., R.I.= 0.787) is association with Collisional tectonics and resetting of K-Ar mineral systems. (author)

  17. Tüketici Fiyat Endeksinin Uyarlamalı Ağa Dayalı Bulanık Çıkarım Sistemi ile Kestirimi / Consumer Price Index Forecast with Adaptive Neuro Fuzzy Inference System

    Directory of Open Access Journals (Sweden)

    Serenay VAROL

    2016-04-01

    Full Text Available Son yıllarda zaman serisi tahmini için birçok alternatif yöntem önerilmiştir. Uyarlamalı ağa dayalı bulanık çıkarım sistemi (ANFIS öngörü problemi için literatürde en çok uygulanan bulanık çıkarım sistemidir. Bu çalışmada tüketici fiyat endeksinin kestiriminde ANFIS’in performansı incelenmiştir. Çalışmanın sonucunda ANFIS yöntemi ile ilgilenilen zaman aralığındaki tüketici fiyat endeksinin kestiriminde ulaşılan sonuçlar yorumlanmıştır. / Alternative methods have been proposed for time series prediction in last years. Adaptive neuro fuzzy inference system (ANFIS is the most used fuzzy inference system in literature for prediction problem. In this study, the performance of ANFIS in forecasting consumer price index is examined, and the results of the consumer price index estimation in time period, on which ANFIS method is applied, are interpreted.

  18. Münih’te Tüketime Sunulan Koyun ve Keçi Peynirlerinde İnek Sütü Karışımının Enzim-İmmünolojik Sandwich-EIA Testi ile Araştırılması

    Directory of Open Access Journals (Sweden)

    Özer Ergün

    2015-02-01

    Full Text Available Münih piyasasında market ve dükkanlarda satışa sunulan yerli veya ithal koyun keçi peynirlerinden 48 adet toplanmış ve Enzim-immünolojik Sandwich-EIA testi ile inek sütü karışımı yönünden incelenmiştir. Numunelerin 27 tanesinde (%56’da inek sütü karışımı tespit edilmiş olup uygulanan testin hassasiyeti %1’dir.

  19. Reviews CD-ROM: Scientific American—The Amateur Scientist 3.0 Book: The New Resourceful Physics Teacher Equipment: DynaKar Book: The Fundamentals of Imaging Book: Teaching Secondary Physics Book: Novel Materials and Smart Applications Equipment: Cryptic disk Web Watch

    Science.gov (United States)

    2012-05-01

    WE RECOMMEND Scientific American—The Amateur Scientist 3.0 Article collection spans the decades DynaKar DynaKar drives dynamics experiments The Fundamentals of Imaging Author covers whole imaging spectrum Teaching Secondary Physics Effective teaching is all in the approach Novel Materials and Smart Applications/Novel materials sample pack Resources kit samples smart materials WORTH A LOOK Cryptic disk Metal disk spins life into discussions about energy, surfaces and kinetics HANDLE WITH CARE The New Resourceful Physics Teacher Book brings creativity to physics WEB WATCH Apps for tablets and smartphones can aid physics teaching

  20. „Słownik wyrazów obcego a mniej jasnego pochodzenia…” Jana Karłowicza – wyrazem wiedzy i zamiłowań lituanistycznych autora

    Directory of Open Access Journals (Sweden)

    Kristina Rutkovska

    2016-12-01

    Full Text Available Dictionary of Foreign Words of the Less Known Origin by Jan Karłowicz – an Expression of Knowledge and Lithuanistic Tastes of Author The object of the description in the article is Lithuanian lexicon occurring in the Dictionary of foreign words of the less known origin (EWS composed by Jan Karłowicz, who was involved in the multifaceted research on the Lithuanian language and culture – he studied the Lithuanian dialect, local names, and initiated research on Lithuanian folklore. He also published materials from Lithuania (ethnographic descriptions, folklore and language descriptions of the Samogitian nobility in the Wisla, previously editing them and adding comments in the text to the Lithuanian vocabulary. His onomastic collections as well as the study About the Lithuanian Language have been rediscovered by Lithuanian linguists who devoted a separate study to them. Solid knowledge of comparative linguistics and his own experience in research the Lithuanian language and culture, work with Lithuanian printed materials, hand­written or derived from field studies in Lithuania, allowed him to use the knowledge and materials in very different ways. Next to words analyzed in the EWS, he included the words of Lithuanian origin and next – Slavic borrowings of Lithuanian dialects, thereby contributing indirectly to the study of foreign lexis in the Lithuanian dia­lects. A similar historic-linguistic interpretation was acceptable in those days when the methodology of etymological research was just developing and every manifestation of language was worth documenting. Karłowicz’s EWS is very important for researchers of the Baltic-Slavic border. He detected a significant part of the Lithuanian lexicon and, more broadly – regional lexicon in intensive Slavic-Lithuanian relations. The greater part of Lithuanianisms was recorded in the mid-nineteenth century, when peasants in Lithuania started massive convertions to the Polish language. At the

  1. Bazı Dondurma Karışımlarının Isıl İletkenliklerinin Sıcaklıkla Değişiminin Belirlenmesi

    Directory of Open Access Journals (Sweden)

    Seher Kumcuoğlu

    2015-02-01

    Full Text Available Bu çalışmada geleneksel ürünlerimizden olan ve modern bir işletmede sürekli sistemde üretilen Maraş usulü ve kaymaklı dondurma karışımlarının  -30 °C ile +30°C sıcaklık aralığındaki  ısıl iletkenlik değerleri çizgisel ısı kaynaklı prob yöntemi kullanılarak deneysel olarak belirlenmiştir. Kalibrasyon materyali olarak % 0.3 agar içeren saf su  kullanılmıştır. Optimum ölçüm koşulları; değişik elektriksel akım, işlem süreleri ve örnek boyutları kullanılarak tespit edilmiştir. Örneklerin donmuş durumlarındaki ısıl iletkenlik değerlerinin donmamış durumlarına ait ısıl iletkenlik değerlerinden daha yüksek olduğu belirlenmiştir.  Maraş usulü dondurma karışımının ısıl iletkenliği 25 °C’de 0.494 W/m.K, –30 °C’de 1.051 W/m.K; kaymaklı dondurma karışımının ısıl iletkenliği ise 25 °C’de 0.452 W/m.K, –30 °C’de 0.993 W/m.K  olarak ölçülmüştür. Örneklerin ısıl iletkenlik değerlerinin bileşim ve sıcaklıkla değişim gösterdiği saptanmıştır.

  2. Receptor-receptor interactions within receptor mosaics. Impact on neuropsychopharmacology.

    Science.gov (United States)

    Fuxe, K; Marcellino, D; Rivera, A; Diaz-Cabiale, Z; Filip, M; Gago, B; Roberts, D C S; Langel, U; Genedani, S; Ferraro, L; de la Calle, A; Narvaez, J; Tanganelli, S; Woods, A; Agnati, L F

    2008-08-01

    Future therapies for diseases associated with altered dopaminergic signaling, including Parkinson's disease, schizophrenia and drug addiction or drug dependence may substantially build on the existence of intramembrane receptor-receptor interactions within dopamine receptor containing receptor mosaics (RM; dimeric or high-order receptor oligomers) where it is believed that the dopamine D(2) receptor may operate as the 'hub receptor' within these complexes. The constitutive adenosine A(2A)/dopamine D(2) RM, located in the dorsal striato-pallidal GABA neurons, are of particular interest in view of the demonstrated antagonistic A(2A)/D(2) interaction within these heteromers; an interaction that led to the suggestion and later demonstration that A(2A) antagonists could be used as novel anti-Parkinsonian drugs. Based on the likely existence of A(2A)/D(2)/mGluR5 RM located both extrasynaptically on striato-pallidal GABA neurons and on cortico-striatal glutamate terminals, multiple receptor-receptor interactions within this RM involving synergism between A(2A)/mGluR5 to counteract D(2) signaling, has led to the proposal of using combined mGluR5 and A(2A) antagonists as a future anti-Parkinsonian treatment. Based on the same RM in the ventral striato-pallidal GABA pathways, novel strategies for the treatment of schizophrenia, building on the idea that A(2A) agonists and/or mGluR5 agonists will help reduce the increased dopaminergic signaling associated with this disease, have been suggested. Such treatment may ensure the proper glutamatergic drive from the mediodorsal thalamic nucleus to the prefrontal cortex, one which is believed to be reduced in schizophrenia due to a dominance of D(2)-like signaling in the ventral striatum. Recently, A(2A) receptors also have been shown to counteract the locomotor and sensitizing actions of cocaine and increases in A(2A) receptors have also been observed in the nucleus accumbens after extended cocaine self-administration, probably

  3. Estrogen receptor and progesterone receptor status of breast cancer patients of eastern India: A multi-institutional study.

    Science.gov (United States)

    Chatterjee, Koushik; Bhaumik, Gautam; Chattopadhyay, Bhargab

    2018-01-01

    There is a paucity of any significant data on the estrogen receptor (ER) and progesterone receptor (PR) status of breast cancer patients from the eastern part of India. This study aims to document the ER and PR status of breast cancer patients in the eastern Indian population, as catered by two premier tertiary care hospitals in Kolkata. All breast cancer patients registered between January 1, 2013 and December 31, 2015, in the Departments of Oncology, of IPGMER and SSKM Hospitals and R. G. Kar Medical College and Hospital, Kolkata, who had at least undergone a core biopsy or surgery, were analyzed retrospectively for documentation of their ER and PR status, using the 2010 American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) interpretation guidelines. Over a period of 3 years, a total of 927 patients were included for the study. A total of 825 (89%) patients had their ER and PR data available for evaluation. ER and PR positive was seen in 312 (37.82%) patients, ER and PR negative in 399 (48.36%) patients, ER positive and PR negative in 71 (8.6%) patients, and ER negative and PR positive results was found in 43 (5.21%) patients. This is the first multi-institutional documentation of ER and PR status from eastern India, having a modest number of patients and one of the earliest documentations using the latest ASCO/CAP interpretation guidelines. These findings resemble the data from the south and also reiterate the fact that majority of the Indian breast cancer patients are still ER and PR negative in spite of the changes in the interpretation guidelines.

  4. Gating characteristics control glutamate receptor distribution and trafficking in vivo.

    Science.gov (United States)

    Petzoldt, Astrid G; Lee, Yü-Hien; Khorramshahi, Omid; Reynolds, Eric; Plested, Andrew J R; Herzel, Hanspeter; Sigrist, Stephan J

    2014-09-08

    Glutamate-releasing synapses dominate excitatory release in the brain. Mechanisms governing their assembly are of major importance for circuit development and long-term plasticity underlying learning and memory. AMPA/Kainate-type glutamate receptors (GluRs) are tetrameric ligand-gated ion channels that open their ion-conducting pores in response to binding of the neurotransmitter. Changes in subunit composition of postsynaptic GluRs are highly relevant for plasticity and development of glutamatergic synapses [1-4]. To date, posttranslational modifications, mostly operating via the intracellular C-terminal domains (CTDs) of GluRs, are presumed to be the major regulator of trafficking [5]. In recent years, structural and electrophysiological analyses have improved our understanding of GluR gating mechanism [6-11]. However, whether conformational changes subsequent to glutamate binding may per se be able to influence GluR trafficking has remained an unaddressed question. Using a Drosophila system allowing for extended visualization of GluR trafficking in vivo, we here provide evidence that mutations changing the gating behavior alter GluR distribution and trafficking. GluR mutants associated with reduced charge transfer segregated from coexpressed wild-type GluRs on the level of individual postsynaptic densities. Segregation was lost upon blocking of evoked glutamate release. Photobleaching experiments suggested increased mobility of mutants with reduced charge transfer, which accumulated prematurely during early steps of synapse assembly, but failed to further increase their level in accordance with assembly of the presynaptic scaffold. In summary, gating characteristics seem to be a new variable for the understanding of GluR trafficking relevant to both development and plasticity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Bazı Şekerlemeler ve Yapay Toz İçeceklerdeki Diazo Boyar Madde Olan Sunset Yellow FCF ile Tartrazin Miktar Tayinlerinin Voltametrik ve Spektrofotometrik Metod Karşılaştırması

    Directory of Open Access Journals (Sweden)

    Nejat Altıniğne

    2015-02-01

    Full Text Available Bazı şekerlemeler ve toz içeceklere katımlı olan sunset yellow FCF ve tartrazin boyar maddelerin analizleri, voltametrik (DPP ve spektrofotometrik metotlarla yapılarak karşılaştırılmıştır. Şekerlemelerde ve sentetik toz içeceklerde boyar maddenin yalnız bir tanesi bulunduğunda, doğru, hassas ve güvenli sonuçlar elde edilebilmektedir. Uygulanan her iki metodun korelasyon sayısı r= 0.995 ve tayin sınıfları 0.8 mg/ml olarak saptanmıştır. Bu çalışma nitel ve nicel tayinlerin, spektrofotometrik metot yanında voltametri metoduyla da yapılabildiğini göstermiştir.

  6. 40Ar/39Ar and K/Ar whole rock age constraints on the timing of regional deformation, South Coast of New South Wales, Lachlan Fold Belt, Southeastern Australia: problems and implications

    International Nuclear Information System (INIS)

    Phillips, D.; Fergusson, C.L.

    1999-01-01

    Full text: Subduction complex rocks are well exposed on the south coast of New South Wales around Batemans Bay. Farther south in the Narooma and Bermagui region, Offier et al (1998) have determined two 40 Ar/ 39 Ar ages of 450 ± 3 Ma and 445 ± 2 Ma. They argued that these ages constrain the timing of intense underplating-related deformation and we have undertaken farther work, from an area south of Batemans Bay, to test this suggestion. The 40 Ar/ 39 Ar method applied to fine-grained, low temperature metamorphic rocks, such as slates, is beset by the problem of recoil loss and/or redistribution of 39 Ar during the irradiation process. Another problem is the difficulty of distinguishing between the contributions to 40 Ar/ 39 Ar spectra from illite/muscovite grown during the cleavage-producing deformation and detrital muscovite/illite. In the current study, four slate samples, with variable contents of detrital white mica, were analysed by both the K-Ar and 40 Ar/ 39 Ar step-heating methods. A separate of detrital white mica from one slate sample yields a plateau age of 500 ± 2 Ma. This result indicates that inheritance has not been eliminated by metamorphism as is commonly assumed and that the 40 Ar/ 39 Ar ages provide only a maximum estimate for the timing of deformation. 40 Ar/ 39 Ar analyses of state chips yield discordant, saddle-shaped age spectra, with minimum, within-saddle' ages of ca. 420 Ma. Two slate samples give identical 40 Ar/ 39 Ar integrated ages of 455 ± 2 Ma. One sample contains relatively abundant detrital bedding-parallel mica flakes that are locally oblique to the regional cleavage in the rock. The 40 Ar/ 39 Ar ages are some 20 Ma older than K-Ar ages for these same samples, suggesting that recoil loss of 39 Ar may also have affected these slates. Both recoil loss of 39 Ar and inherited white micas will yield elevated apparent ages, thus providing only maximum ages for the cleavage-producing deformation. Two other samples from slaty tectonic

  7. Birinci basamak Helikobakter pilori eradikasyon tedavisinde 7 ve 14 günlük lansoprazol, amoksisilin, metronidazol protokolünün karşılaştırılması

    OpenAIRE

    UYGUN, Ahmet; KANTARCIOĞLU, Murat; POLAT, Zülfikar; KİLCİLER, Güldem; GÜLŞEN, Mustafa

    2010-01-01

    Giriş ve Amaç: Ülkemizde günümüzde birinci basamak Helikobakter pilori eradikasyon tedavisinde protokollerin süresi ve eradikasyon oranları konusunda tartışmalar sürmektedir. Bu çalışmadaki amacımız; nonülser dispepsili Helikobakter pilori pozitif hastalarda lansoprazol, amoksisilin, metronidazol'den oluşan 7 ve 14 günlük tedavi protokollerinin eradikasyon oranlarını karşılaştırmaktır. Gereç ve Yöntem: Çalışmaya Helikobakter pilori pozitif nonülser dispepsili 180 hasta (84 kadın,...

  8. Helicobacter pylori eradikasyon tedavisinde 7 ve 14 günlük lansoprazol, amoksisilin, klaritromisin protokolünün karşılaştırılması

    OpenAIRE

    UYGUN, Ahmet; TÜZÜN, Ahmet; YEŞİLOVA, Zeki; ASLAN, Murat; ATEŞ, Yüksel; POLAT, Zülfikar; ERDİL, Ahmet; BAĞCI, Sait; GÜNHAN, Ömer; GÜLŞEN, Mustafa; DAĞALP, Kemal

    2015-01-01

    Giriş ve amaç: Günümüzde birinci basamak Helicobacter pylori (Hp) eradikasyon tedavisinde protokollerin süresi ve eradikasyon oranları konusunda tartışmalar sürmektedir. Bu çalışmadaki amacımız; nonülser dispepsili Hp pozitif hastalarda lansoprazol, klaritromisin ve amoksisilin'den oluşan 7 ve 14 günlük tedavi protokollerinin eradikasyon oranları nı karşılaştırmaktır. Gereç ve yöntem: Çalışmaya Hp pozitif nonülser dispepsili 188 hasta (92 kadın, 96 erkek, ortalama yaş 44.8 yıl) alı...

  9. Elma Bahçelerinde Bazı Önemli Zararlılara Karşı Azadirachtin ve Kaolin Uygulamalarının Etkisi

    Directory of Open Access Journals (Sweden)

    Nazım KÜÇÜKBALLI

    2018-02-01

    Full Text Available Elma bahçelerinde ekonomik kayıplara neden olan birçok hastalık, zararlı ve yabancıot türü bulunmaktadır. Zararlılar içinde elma içkurdu, kırmızıörümcekler ve yaprakbitleri ana zararlılar arasında yer almaktadır. Elma üretiminin yoğun yapıldığı Isparta ilinde özellikle yağışlı geçen yıllarda yılda 20 kezden daha fazla ilaçlama yapıldığı bilinmektedir. Bu çalışmada söz konusu zararlılara karşı çevre ve yararlılara fazla etkisi olmadığı bilinen azadirachtin ve kaolinin etkisi 2015 yılında incelenmiştir. Denemeler Süleyman Demirel Üniversitesi, Ziraat Fakültesi bünyesinde bulunan 5 ve 2 dekarlık iki elma bahçesinde yürütülmüştür. Her bahçe dört parsele ayrılmış ve her bir parsele kaolin, azadirachtin (neem, karşılaştırma ilacı olarak chlorpyrifos-ethyl ve Kontrol parseline de su püskürtme şeklinde uygulanmıştır. Denemeler tesadüf blokları deneme desenine göre kurulmuş olup, her tekerrürde 8 ağaç olacak şekilde 6 tekerrürlü olarak düzenlenmiştir. Her hafta, her bir ağaçtan 40 yaprak örneği alınarak Tetranychus urticae, Pananychus ulmi, Aphis pomi ve Dysaphis plantaginea sayımları yapılmıştır. Elma içkurdu zararı ise hasat zamanında ağaç üzerinde ve yere düşen meyvelerde bulaşma oranına göre belirlenmiştir. Çalışma sonucunda yaprakbitine karşı en etkili Chlorpyrifos-ethyl bulunmuş, bunu kaolin ve neem izlemiştir. Preparatlar kırmızıörümceklere karşı benzer etki gösterirken elma içkurdu bulaşma oranları sırasıyla, kontrol parselinde %49.99, kaolin parselinde %42.27, neem parselinde %41.20 ve chlorpyrifos-ethyl parselinde %31.23 olmuştur.

  10. 40Ar/39Ar laster fusion and K-Ar ages from Lathrop Wells, Nevada, and Cima, California: The age of the latest volcanic activity in the Yucca Mountain area

    International Nuclear Information System (INIS)

    Turrin, B.D.; Champion, D.E.

    1991-01-01

    K-Ar and 40 Ar/ 39 Ar ages from the Lathrop Wells volcanic center, Nevada, and from the Cima volcanic field, California, indicate that the recently reported 20-ka age estimate for the Lathrop Wells volcanic center is incorrect. Instead, an age of 119 ± 11 to 141 ± 10 ka is indicated for the Lathrop Wells volcanic center. This age corrected is concordant with the ages determined by two independent isotopic geochronometric techniques and with the stratigraphy of surficial deposits in the Yucca Mountain region. In addition, paleomagnetic data and radiometric age data indicate only two volcanic events at the Lathrop Wells volcanic center that are probably closely linked in time, not as many as five as recently reported. 32 refs., 2 figs., 2 tabs

  11. Kars ilinde şeker pancarı üretiminin beşeri ve ekonomik önemi, sürdürülebilirliği

    OpenAIRE

    DEMİR, MUCİP

    2017-01-01

    Türkiye’nin kuzeydoğusunda yer alan Kars İlinin büyük kısmı ortalama irtifası 2000 metre civarında bulunan ve volkanik malzemelerle örtülmüş plato sahasında yer almaktadır. İldeki genel morfolojik ve jeolojik özellikler nedeniyle kışları oldukça soğuk, karlı, yazları serin ve yağışlı sert karasal iklim görülmekte bu nedenle bitkisel üretim faaliyetleri yerine daha çok hayvancılık faaliyetleri yapılmaktadır. İlde şeker pancarı üretimi daha çok ilin kuzeyindeki Akyaka ve Arpaçay ilçelerinde...

  12. K/Ar and 40Ar/39Ar dating of emerald mineralizations from Brazil. Evidence of Transamazonian (2 Ga) and Brazilian (650 - 500 Ma) ages. Influence of phlogopite crystallo-chemistry on argon retention

    International Nuclear Information System (INIS)

    Ribeiro-Althoff, A.M.

    1997-01-01

    The emerald deposits of Brazil are always found within basic and ultra-basic formations which have been metasomatized by hydrothermal fluids, and transformed into phlogopitites. Two types of deposits may be distinguished: one associated with pegmatites, the other with shear zones. In both cases the precipitation of emerald is contemporaneous with that of phlogopite. The age of these has been determined by dating of the latter, using K-Ar and 40 Ar/ 39 Ar methods. Deposits associated with pegmatite have ages between 2.0 et 1.9 Ga (Carnaiba, Socoto), and between 650 et 500 Ma (Pombos, Juca, Pirenoplis, Capoeirana, Coqui). The Santa Terezinha deposit, associated with a shear zone where pegmatites are absent, gives an age of formation of 520 Ma. These results show that brazilian emeralds were formed during two distinct orogenic periods: the Transamazonian (2.0 Ga), in the Sao Francisco craton, and the Brasilian (650 - 500 Ma)

  13. Devital dişlerin ıntrakoronal ağartmasında kullanılan iki farklı materyalin klinik etkinliğinin karşılaştırılması

    OpenAIRE

    Keçeci, Diljin

    2009-01-01

    SüleymanDemirel Üniversitesi TIP FAKÜLTESİ DERGİSİ: 2006 Eylül; 13(3) Devital dişlerin ıntrakoronal ağartmasında kullanılan iki farklı materyalin klinik etkinliğinin karşılaştırılması Diljin Keçeci Devital diş renklenmeleri diş dizisinde kolayca ayırt edilebildiği için özellikle ön dişlerde estetik sorunlara yol açmaktadır. Bu çalışmada kanal tedavisi uygulanmış veya travmaya maruz kalmış, ön dişlerde ortaya çıkan renklenmelerin ağartılması amacıyla bir sodyum perborat (Starbrite, Dentr...

  14. Acetylcholine receptor antibody

    Science.gov (United States)

    ... medlineplus.gov/ency/article/003576.htm Acetylcholine receptor antibody To use the sharing features on this page, please enable JavaScript. Acetylcholine receptor antibody is a protein found in the blood of ...

  15. Cooperative ethylene receptor signaling

    OpenAIRE

    Liu, Qian; Wen, Chi-Kuang

    2012-01-01

    The gaseous plant hormone ethylene is perceived by a family of five ethylene receptor members in the dicotyledonous model plant Arabidopsis. Genetic and biochemical studies suggest that the ethylene response is suppressed by ethylene receptor complexes, but the biochemical nature of the receptor signal is unknown. Without appropriate biochemical measures to trace the ethylene receptor signal and quantify the signal strength, the biological significance of the modulation of ethylene responses ...

  16. The combination of glutamate receptor antagonist MK-801 with tamoxifen and its active metabolites potentiates their antiproliferative activity in mouse melanoma K1735-M2 cells

    International Nuclear Information System (INIS)

    Ribeiro, Mariana P.C.; Nunes-Correia, Isabel; Santos, Armanda E.; Custódio, José B.A.

    2014-01-01

    Recent reports suggest that N-methyl-D-aspartate receptor (NMDAR) blockade by MK-801 decreases tumor growth. Thus, we investigated whether other ionotropic glutamate receptor (iGluR) antagonists were also able to modulate the proliferation of melanoma cells. On the other hand, the antiestrogen tamoxifen (TAM) decreases the proliferation of melanoma cells, and is included in combined therapies for melanoma. As the efficacy of TAM is limited by its metabolism, we investigated the effects of the NMDAR antagonist MK-801 in combination with TAM and its active metabolites, 4-hydroxytamoxifen (OHTAM) and endoxifen (EDX). The NMDAR blockers MK-801 and memantine decreased mouse melanoma K1735-M2 cell proliferation. In contrast, the NMDAR competitive antagonist APV and the AMPA and kainate receptor antagonist NBQX did not affect cell proliferation, suggesting that among the iGluR antagonists only the NMDAR channel blockers inhibit melanoma cell proliferation. The combination of antiestrogens with MK-801 potentiated their individual effects on cell biomass due to diminished cell proliferation, since it decreased the cell number and DNA synthesis without increasing cell death. Importantly, TAM metabolites combined with MK-801 promoted cell cycle arrest in G1. Therefore, the data obtained suggest that the activity of MK-801 and antiestrogens in K1735-M2 cells is greatly enhanced when used in combination. - Highlights: • MK-801 and memantine decrease melanoma cell proliferation. • The combination of MK-801 with antiestrogens inhibits melanoma cell proliferation. • These combinations greatly enhance the effects of the compounds individually. • MK-801 combined with tamoxifen active metabolites induces cell cycle arrest in G1. • The combination of MK-801 and antiestrogens is an innovative strategy for melanoma

  17. An N-methyl-D-aspartate receptor mediated large, low-frequency, spontaneous excitatory postsynaptic current in neonatal rat spinal dorsal horn neurons.

    Science.gov (United States)

    Thomson, L M; Zeng, J; Terman, G W

    2006-09-01

    Examples of spontaneous oscillating neural activity contributing to both pathological and physiological states are abundant throughout the CNS. Here we report a spontaneous oscillating intermittent synaptic current located in lamina I of the neonatal rat spinal cord dorsal horn. The spontaneous oscillating intermittent synaptic current is characterized by its large amplitude, slow decay time, and low-frequency. We demonstrate that post-synaptic N-methyl-D-aspartate receptors (NMDARs) mediate the spontaneous oscillating intermittent synaptic current, as it is inhibited by magnesium, bath-applied d-2-amino-5-phosphonovalerate (APV), or intracellular MK-801. The NR2B subunit of the NMDAR appears important to this phenomenon, as the NR2B subunit selective NMDAR antagonist, alpha-(4-hydroxphenyl)-beta-methyl-4-benzyl-1-piperidineethanol tartrate (ifenprodil), also partially inhibited the spontaneous oscillating intermittent synaptic current. Inhibition of spontaneous glutamate release by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or the mu-opioid receptor agonist [D-Ala2, N-Me-Phe4, Gly5] enkephalin-ol (DAMGO) inhibited the spontaneous oscillating intermittent synaptic current frequency. Marked inhibition of spontaneous oscillating intermittent synaptic current frequency by tetrodotoxin (TTX), but not post-synaptic N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314), suggests that the glutamate release important to the spontaneous oscillating intermittent synaptic current is dependent on active neural processes. Conversely, increasing dorsal horn synaptic glutamate release by GABAA or glycine inhibition increased spontaneous oscillating intermittent synaptic current frequency. Moreover, inhibiting glutamate transporters with threo-beta-benzyloxyaspartic acid (DL-TBOA) increased spontaneous oscillating intermittent synaptic current frequency and decay time. A possible functional role of this spontaneous NMDAR

  18. GABA receptor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Doo [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-04-15

    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABA{sub A}-receptor that allows chloride to pass through a ligand gated ion channel and GABA{sub B}-receptor that uses G-proteins for signaling. The GABA{sub A}-receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABA{sub A}-receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with {sup 11}C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, {sup 18}F-fluoroflumazenil (FFMZ) has been developed to overcome {sup 11}C's short half-life. {sup 18}F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '1{sup 1}C-FMZ PET instead of {sup 18}F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABA{sub A} receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas.

  19. GABA receptor imaging

    International Nuclear Information System (INIS)

    Lee, Jong Doo

    2007-01-01

    GABA is primary an inhibitory neurotransmitter that is localized in inhibitory interneurons. GABA is released from presynaptic terminals and functions by binding to GABA receptors. There are two types of GABA receptors, GABA A -receptor that allows chloride to pass through a ligand gated ion channel and GABA B -receptor that uses G-proteins for signaling. The GABA A -receptor has a GABA binding site as well as a benzodiazepine binding sites, which modulate GABA A -receptor function. Benzodiazepine GABAA receptor imaging can be accomplished by radiolabeling derivates that activates benzodiazepine binding sites. There has been much research on flumazenil (FMZ) labeled with 11 C-FMZ, a benzodiazepine derivate that is a selective, reversible antagonist to GABAA receptors. Recently, 18 F-fluoroflumazenil (FFMZ) has been developed to overcome 11 C's short half-life. 18 F-FFMZ shows high selective affinity and good pharmacodynamics, and is a promising PET agent with better central benzodiazepine receptor imaging capabilities. In an epileptic focus, because the GABA/benzodiazepine receptor amount is decreased, using '1 1 C-FMZ PET instead of 18 F-FDG, PET, restrict the foci better and may also help find lesions better than high resolution MR. GABA A receptors are widely distributed in the cerebral cortex, and can be used as an viable neuronal marker. Therefore it can be used as a neuronal cell viability marker in cerebral ischemia. Also, GABA-receptors decrease in areas where neuronal plasticity develops, therefore, GABA imaging can be used to evaluate plasticity. Besides these usages, GABA receptors are related with psychological diseases, especially depression and schizophrenia as well as cerebral palsy, a motor-related disorder, so further in-depth studies are needed for these areas

  20. Swiss Albino Farelerde Fenpiroksimat (Akarisit’ın Teşvik Ettiği Biyokimyasal Değişime Karşı Fındığın Koruyucu Rolü

    Directory of Open Access Journals (Sweden)

    Kültiğin ÇAVUŞOĞLU

    2017-02-01

    Full Text Available Özet. Fenpiroksimat Tetranychidae, Eriophyiidae ve Tarsonemidae ailelerindeki önemli fitofag akarlarına karşı mücadelede kullanılan pirazol bir akarisittir. Bu çalışmanın amacı, Swiss albino farelerde seçilen biyokimyasal parametreler üzerine Fenpiroksimat akarisitinin toksisitesini değerlendirmek ve bu biyokimyasal değişimlere karşı fındığın koruyucu rolünü araştırmaktır. Fareler rastgele bir (1 kontrol ve üç (3 uygulama olmak üzere toplam dört (4 gruba ayrılmıştır. Deneysel periyodun sonunda, tüm fareler hafif eter anestezisi altında bayıltılmış, biyokimyasal analiz ve ölçümler için kan örnekleri ile karaciğer ve böbrek dokuları elde edilmiştir. Serum Aspartat Aminotransferaz (AST, Alanin Aminotransferaz (ALT, Kan Üre Nitrojen (BUN ve kreatinin seviyeleri ölçülmüş, elde edilen dokularda ise Malondialdehit (MDA ve Glutatyon (GSH seviyeleri analiz edilmiştir. Sonuçta, kontrol grubu ile karşılaştırıldığında Fenpiroksimat uygulanan farelerde GSH seviyelerinde önemli bir azalma (p<0.05, AST, ALT, BUN, kreatinin ve MDA seviyelerinde ise önemli bir artış (p<0.05 görülmüştür. Fenpiroksimat uygulama grubu ile karşılaştırıldığında, Fenpiroksimat ile birlikte fındık uygulaması GSH seviyelerinde tekrar önemli bir artışa (p<0.05, AST, ALT, BUN, kreatinin ve MDA seviyelerinde ise önemli bir azalmaya (p<0.05 neden olmuştur. Sonuç olarak, fındık ile beslemenin Fenpiroksimat tarafından teşvik edilen biyokimyasal hasara karşı önemli bir koruma sağladığı söylenebilir.Anahtar Kelimeler: Albino fare, fenpiroksimat, oksidatif stres, serum parametresi Abstract. Fenpyroximate is a pyrazole acaricide with selective activity against important phytophagous mites in the families’ Tetranychidae, Eriophyiidae, and Tarsonemidae. The goal of this study was to evaluate the toxicity of Fenpyroximate acaricide on selected biochemical parameters in Swiss albino mice. And

  1. Glucocorticoid receptor modulators.

    Science.gov (United States)

    Meijer, Onno C; Koorneef, Lisa L; Kroon, Jan

    2018-06-01

    The glucocorticoid hormone cortisol acts throughout the body to support circadian processes and adaptation to stress. The glucocorticoid receptor is the target of cortisol and of synthetic glucocorticoids, which are used widely in the clinic. Both agonism and antagonism of the glucocorticoid receptor may be beneficial in disease, but given the wide expression of the receptor and involvement in various processes, beneficial effects are often accompanied by unwanted side effects. Selective glucocorticoid receptor modulators are ligands that induce a receptor conformation that allows activation of only a subset of downstream signaling pathways. Such molecules thereby combine agonistic and antagonistic properties. Here we discuss the mechanisms underlying selective receptor modulation and their promise in treating diseases in several organ systems where cortisol signaling plays a role. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  2. Dengue virus receptor

    OpenAIRE

    Hidari, Kazuya I.P.J.; Suzuki, Takashi

    2011-01-01

    Dengue virus is an arthropod-borne virus transmitted by Aedes mosquitoes. Dengue virus causes fever and hemorrhagic disorders in humans and non-human primates. Direct interaction of the virus introduced by a mosquito bite with host receptor molecule(s) is crucial for virus propagation and the pathological progression of dengue diseases. Therefore, elucidation of the molecular mechanisms underlying the interaction between dengue virus and its receptor(s) in both humans and mosquitoes is essent...

  3. U/Pb (SHRIMP), 207Pb/206Pb, Rb/Sr, Sm/Nd e K/Ar geochronology of granite-greenstone terrains of Gaviao Block: implications for the Proterozoic and Archean evolution of Sao Francisco Craton, Brazil

    International Nuclear Information System (INIS)

    Leal, Luiz Rogerio Bastos

    1998-01-01

    The Gaviao Block (GB) in the northern portion of the Sao Francisco Craton-Northeast of Brazil, constitutes one of the oldest Archean fragments of the South American Platform Archean crust. GB underwent several events of juvenile accretion and reworking of continental crust along its evolutionary history, notably between the Archean and the Paleoproterozoic. 207 Pb/ 206 Pb isotopic analyses were carried out in two zircons populations from strongly migmatized TTG terranes found in the proximity of Brumado: the first population (7 crystals) is taken as representative of the crystallization period of the TTG terranes at 3300 ± 45 Ma; the second (2 crystals) represents the age of the first even of metamorphism/migmatization at 2910 ± 10 Ma. 207 Pb/ 206 Pb analyses in zircons from an outcrop of non-migmatized TTG in the area yielded a 3202 ± 15 Ma age (4 crystals), interpreted to be the crystallization period of the gneiss protolith. Sm/Nd analyses on the TTG rocks of the Brumado region yielded T DM model ages varying between 3.26 and 3.36 Ga and ε Nd (t) between -3.5 and +0.7. These data suggest the occurrence of juvenile accretions to the continental crust during the Archean, with differential involvement of crustal materials. The geochemical data of rare earth elements corresponding to the TTG terranes revealed moderate LRRE contents (La N =83,5), low HREE contents (La N =2,5) and a fairly fractionated pattern (La/Yb) N =34, besides lack of negative Eu anomaly, showing that these rocks have similar compositions to those TTG terranes of cratonic continents, as well as some Archean rocks from CSF (e.g. Sete Voltas, Boa Vista). Finally, the youngest ages present in GB rocks (ca. 1.2-0.45 Ga) represent the role played by tectono thermal events, which produced partial or total rejuvenation of the Rb/Sr and K/Ar isotopic systems during the Espinhaco and Brasiliano cycles. In particular, K/Ar ages illustrate the effect of younger regional cooling episodes related to the

  4. Organize Sanayi Bölgelerinde Faaliyet Gösteren Firmaların Karşılaştıkları İhracat Engelleri: Mersin Tarsus Organize Sanayi Bölgesinde Bir Uygulama

    Directory of Open Access Journals (Sweden)

    Eda YAŞA ÖZELTÜRKAY

    2014-09-01

    Full Text Available Dış ticaret faaliyetleri, ülke ekonomileri açısından çok önemli bir yere sahiptir. Bu ekonomik katılımlardan yararlanılırken çeşitli güçlüklerle de karşılaşılabilinmektedir. Dış ticaret faaliyetlerini yürüten işletmeler açısından maliyet çok önemli bir unsurdur. Hükümetlerin bu unsuru göz önüne alarak gerçekleştirmiş olduğu maliyet azaltıcı alt yapı faaliyetlerinden biri de organize sanayi bölgeleridir. Bu çalışma Mersin-Tarsus Organize Sanayi Bölgesinde faaliyet gösteren ve ihracat yapan firmalara ihracat yaparken karşılaşmış oldukları engelleri belirlemek amacıyla uygulanmıştır. 108 firmaya gönderilen anket formlarından 49 tanesi değerlendirmeye uygun olarak geri dönmüştür. Tanımlayıcı bir araştırma olan bu çalışmada literatüre dayalı araştırma soruları oluşturulmuştur. Çalışmadaki verilerin analizinde faktör analizi, güvenilirlik analizi ve tanımlayıcı istatistikî analizlerden faydalanılmıştır. Faktör analizi sonucu, değişkenler yedi alt başlık altında toplanmıştır: firmanın kendi yetersizlikleri, dış pazar ortamına ilişkin engeller, finansal engeller, bilgi eksikliği, bürokratik engeller, kültürel farklılıklar ve ulaşım maliyetleri ve destek eksiklikleri.

  5. Organize Sanayi Bölgelerinde Faaliyet Gösteren Firmaların Karşılaştıkları İhracat Engelleri: Mersin Tarsus Organize Sanayi Bölgesinde Bir Uygulama

    Directory of Open Access Journals (Sweden)

    Eda YAŞA ÖZELTÜRKAY

    2014-12-01

    Full Text Available Dış ticaret faaliyetleri, ülke ekonomileri açısından çok önemli bir yere sahiptir. Bu ekonomik katılımlardan yararlanılırken çeşitli güçlüklerle de karşılaşılabilinmektedir. Dış ticaret faaliyetlerini yürüten işletmeler açısından maliyet çok önemli bir unsurdur. Hükümetlerin bu unsuru göz önüne alarak gerçekleştirmiş olduğu maliyet azaltıcı alt yapı faaliyetlerinden biri de organize sanayi bölgeleridir. Bu çalışma Mersin-Tarsus Organize Sanayi Bölgesinde faaliyet gösteren ve ihracat yapan firmalara ihracat yaparken karşılaşmış oldukları engelleri belirlemek amacıyla uygulanmıştır. 108 firmaya gönderilen anket formlarından 49 tanesi değerlendirmeye uygun olarak geri dönmüştür. Tanımlayıcı bir araştırma olan bu çalışmada literatüre dayalı araştırma soruları oluşturulmuştur. Çalışmadaki verilerin analizinde faktör analizi, güvenilirlik analizi ve tanımlayıcı istatistikî analizlerden faydalanılmıştır. Faktör analizi sonucu, değişkenler yedi alt başlık altında toplanmıştır: firmanın kendi yetersizlikleri, dış pazar ortamına ilişkin engeller, finansal engeller, bilgi eksikliği, bürokratik engeller, kültürel farklılıklar ve ulaşım maliyetleri ve destek eksiklikleri.

  6. Dopamine D4 receptor activation increases hippocampal gamma oscillations by enhancing synchronization of fast-spiking interneurons.

    Directory of Open Access Journals (Sweden)

    Richard Andersson

    Full Text Available BACKGROUND: Gamma oscillations are electric activity patterns of the mammalian brain hypothesized to serve attention, sensory perception, working memory and memory encoding. They are disrupted or altered in schizophrenic patients with associated cognitive deficits, which persist in spite of treatment with antipsychotics. Because cognitive symptoms are a core feature of schizophrenia it is relevant to explore signaling pathways that potentially regulate gamma oscillations. Dopamine has been reported to decrease gamma oscillation power via D1-like receptors. Based on the expression pattern of D4 receptors (D4R in hippocampus, and pharmacological effects of D4R ligands in animals, we hypothesize that they are in a position to regulate gamma oscillations as well. METHODOLOGY/PRINCIPAL FINDINGS: To address this hypothesis we use rat hippocampal slices and kainate-induced gamma oscillations. Local field potential recordings as well as intracellular recordings of pyramidal cells, fast-spiking and non-fast-spiking interneurons were carried out. We show that D4R activation with the selective ligand PD168077 increases gamma oscillation power, which can be blocked by the D4R-specific antagonist L745,870 as well as by the antipsychotic drug Clozapine. Pyramidal cells did not exhibit changes in excitatory or inhibitory synaptic current amplitudes, but inhibitory currents became more coherent with the oscillations after application of PD168077. Fast-spiking, but not non-fast spiking, interneurons, increase their action potential phase-coupling and coherence with regard to ongoing gamma oscillations in response to D4R activation. Among several possible mechanisms we found that the NMDA receptor antagonist AP5 also blocks the D4R mediated increase in gamma oscillation power. CONCLUSIONS/SIGNIFICANCE: We conclude that D4R activation affects fast-spiking interneuron synchronization and thereby increases gamma power by an NMDA receptor-dependent mechanism. This

  7. Hrob nemlčí pevněji nežli Vy : (Dopisy Jiřího Karáska, Arnošta Procházky, Jiřiny Böhmové a Antonína Trýba)

    Czech Academy of Sciences Publication Activity Database

    Färber, Vratislav (ed.)

    2007-01-01

    Roč. 18, č. 4 (2007), s. 163-170 ISSN 0862-6928 R&D Projects: GA ČR GA405/05/2152 Institutional research plan: CEZ:AV0Z90560517 Keywords : Kamil Fiala * Jiří Karásek ze Lvovic * Arnošt Procházka * Jiřina Böhmová * Antnoní Trýb Subject RIV: AJ - Letters, Mass-media, Audiovision

  8. Angiotensin type 2 receptors

    DEFF Research Database (Denmark)

    Sumners, Colin; de Kloet, Annette D; Krause, Eric G

    2015-01-01

    In most situations, the angiotensin AT2-receptor (AT2R) mediates physiological actions opposing those mediated by the AT1-receptor (AT1R), including a vasorelaxant effect. Nevertheless, experimental evidence vastly supports that systemic application of AT2R-agonists is blood pressure neutral...

  9. Altered gamma oscillations during pregnancy through loss of δ subunit-containing GABAA receptors on parvalbumin interneurons

    Directory of Open Access Journals (Sweden)

    Isabella eFerando

    2013-09-01

    Full Text Available Gamma (γ oscillations (30-120 Hz, an emergent property of neuronal networks, correlate with memory, cognition and encoding. In the hippocampal CA3 region, locally generated γ oscillations emerge through feedback between inhibitory parvalbumin-positive basket cells (PV+BCs and the principal (pyramidal cells. PV+BCs express δ-subunit-containing GABAARs (-GABAARs and NMDA receptors (NMDA-Rs that balance the frequency of γ oscillations. Neuroactive steroids (NS, such as the progesterone-derived (3α,5α-3-hydroxy-pregnan-20-one (allopregnanolone; ALLO, modulate the expression of δ-GABAARs and the tonic conductance they mediate. Pregnancy produces large increases in ALLO and brain-region-specific homeostatic changes in δ-GABAARs expression. Here we show that in CA3, where most PV+ interneurons (INs express δ-GABAARs, expression of δ-GABAARs on INs diminishes during pregnancy, but reverts to control levels within 48 hours postpartum. These anatomical findings were corroborated by a pregnancy-related increase in the frequency of kainate-induced CA3 γ oscillations in vitro that could be countered by the NMDA-R antagonists D-AP5 and PPDA. Mimicking the typical hormonal conditions during pregnancy by supplementing 100 nM ALLO lowered the γ frequencies to levels found in virgin or postpartum mice. Our findings show that states of altered NS levels (e.g., pregnancy may provoke perturbations in γ oscillatory activity through direct effects on the GABAergic system, and underscore the importance of δ-GABAARs homeostatic plasticity in maintaining constant network output despite large hormonal changes. Inaccurate coupling of NS levels to δ-GABAAR expression may facilitate abnormal neurological and psychiatric conditions such as epilepsy, post-partum depression, and post-partum psychosis, thus providing insights into potential new treatments.

  10. Glutamate receptor agonists

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Greenwood, Jeremy R; Bunch, Lennart

    2011-01-01

    The neurotransmitter (S)-glutamate [(S)-Glu] is responsible for most of the excitatory neurotransmission in the central nervous system. The effect of (S)-Glu is mediated by both ionotropic and metabotropic receptors. Glutamate receptor agonists are generally a-amino acids with one or more...... stereogenic centers due to strict requirements in the agonist binding pocket of the activated state of the receptor. By contrast, there are many examples of achiral competitive antagonists. The present review addresses how stereochemistry affects the activity of glutamate receptor ligands. The review focuses...... mainly on agonists and discusses stereochemical and conformational considerations as well as biostructural knowledge of the agonist binding pockets, which is useful in the design of glutamate receptor agonists. Examples are chosen to demonstrate how stereochemistry not only determines how the agonist...

  11. AMPA receptor ligands

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian

    2004-01-01

    Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player in the f......Alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR), subtype of the ionotropic glutamate receptors (IGRs), mediate fast synaptic transmission in the central nervous system (CNS), and are involved in many neurological disorders, as well as being a key player...... in the formation of memory. Hence, ligands affecting AMPARs are highly important for the study of the structure and function of this receptor, and in this regard polyamine-based ligands, particularly polyamine toxins, are unique as they selectively block Ca2+ -permeable AMPARs. Indeed, endogenous intracellular...

  12. GLYX-13, a NMDA receptor glycine-site functional partial agonist, induces antidepressant-like effects without ketamine-like side effects.

    Science.gov (United States)

    Burgdorf, Jeffrey; Zhang, Xiao-lei; Nicholson, Katherine L; Balster, Robert L; Leander, J David; Stanton, Patric K; Gross, Amanda L; Kroes, Roger A; Moskal, Joseph R

    2013-04-01

    Recent human clinical studies with the NMDA receptor (NMDAR) antagonist ketamine have revealed profound and long-lasting antidepressant effects with rapid onset in several clinical trials, but antidepressant effects were preceded by dissociative side effects. Here we show that GLYX-13, a novel NMDAR glycine-site functional partial agonist, produces an antidepressant-like effect in the Porsolt, novelty induced hypophagia, and learned helplessness tests in rats without exhibiting substance abuse-related, gating, and sedative side effects of ketamine in the drug discrimination, conditioned place preference, pre-pulse inhibition and open-field tests. Like ketamine, the GLYX-13-induced antidepressant-like effects required AMPA/kainate receptor activation, as evidenced by the ability of NBQX to abolish the antidepressant-like effect. Both GLYX-13 and ketamine persistently (24 h) enhanced the induction of long-term potentiation of synaptic transmission and the magnitude of NMDAR-NR2B conductance at rat Schaffer collateral-CA1 synapses in vitro. Cell surface biotinylation studies showed that both GLYX-13 and ketamine led to increases in both NR2B and GluR1 protein levels, as measured by Western analysis, whereas no changes were seen in mRNA expression (microarray and qRT-PCR). GLYX-13, unlike ketamine, produced its antidepressant-like effect when injected directly into the medial prefrontal cortex (MPFC). These results suggest that GLYX-13 produces an antidepressant-like effect without the side effects seen with ketamine at least in part by directly modulating NR2B-containing NMDARs in the MPFC. Furthermore, the enhancement of 'metaplasticity' by both GLYX-13 and ketamine may help explain the long-lasting antidepressant effects of these NMDAR modulators. GLYX-13 is currently in a Phase II clinical development program for treatment-resistant depression.

  13. K-Ar ages of clay-size concentrates from the mineralisation of the Pedroches Batholith, Spain, and evidence for Mesozoic hydrothermal activity associated with the break up of Pangaea

    Energy Technology Data Exchange (ETDEWEB)

    Halliday, A.N. (Scottish Universities Research and Reactor Centre, Glasgow (UK)); Mitchell, J.G. (Newcastle upon Tyne Univ. (UK). School of Physics)

    1984-05-01

    The K-Ar ages of 32 clay concentrates extracted from samples of ore, gangue and wallrock associated with mineralisation in the Pedroches Batholith lie in the range 119-285 Ma. Although some of the mineralisation is of Permian age more than half of the ages lie between 210 and 230 Ma and indicate a hydrothermal event at this (Triassic) time. A comparison with age data for mineralisation and certain anorogenic magmatism in other areas of the North Atlantic reveals a consistent pattern of a major event at ca. 230-210 Ma and a minor event at ca. 160 Ma with little Cretaceous or Tertiary activity. It is proposed that the ca. 230-210 Ma event was related to an initial rapid fracturing of the crust associated with the break up of Pangaea, which was related with an increase in the geothermal gradient and penetration of the deep crust by surface waters which returned via both new and rejuvenated fissure systems.

  14. K-Ar ages of clay-size concentrates from the mineralisation of the Pedroches Batholith, Spain, and evidence for Mesozoic hydrothermal activity associated with the break up of Pangaea

    International Nuclear Information System (INIS)

    Halliday, A.N.; Mitchell, J.G.

    1984-01-01

    The K-Ar ages of 32 clay concentrates extracted from samples of ore, gangue and wallrock associated with mineralisation in the Pedroches Batholith lie in the range 119-285 Ma. Although some of the mineralisation is of Permian age more than half of the ages lie between 210 and 230 Ma and indicate a hydrothermal event at this (Triassic) time. A comparison with age data for mineralisation and certain anorogenic magmatism in other areas of the North Atlantic reveals a consistent pattern of a major event at ca. 230-210 Ma and a minor event at ca. 160 Ma with little Cretaceous or Tertiary activity. It is proposed that the ca. 230-210 Ma event was related to an initial rapid fracturing of the crust associated with the break up of Pangaea, which was related with an increase in the geothermal gradient and penetration of the deep crust by surface waters which returned via both new and rejuvenated fissure systems. (orig.)

  15. Lipophorin Receptor: The Insect Lipoprotein Receptor

    Indian Academy of Sciences (India)

    IAS Admin

    Director of ... function of the Lp is to deliver lipids throughout the insect body for metabolism ... Lipid is used as a major energy source for development as well as other metabolic .... LpR4 receptor variant was expressed exclusively in the brain and.

  16. Serotonin Receptors in Hippocampus

    Science.gov (United States)

    Berumen, Laura Cristina; Rodríguez, Angelina; Miledi, Ricardo; García-Alcocer, Guadalupe

    2012-01-01

    Serotonin is an ancient molecular signal and a recognized neurotransmitter brainwide distributed with particular presence in hippocampus. Almost all serotonin receptor subtypes are expressed in hippocampus, which implicates an intricate modulating system, considering that they can be localized as autosynaptic, presynaptic, and postsynaptic receptors, even colocalized within the same cell and being target of homo- and heterodimerization. Neurons and glia, including immune cells, integrate a functional network that uses several serotonin receptors to regulate their roles in this particular part of the limbic system. PMID:22629209

  17. Batı Karadeniz Bölgesi Düzce Ekolojik Koşulları Altında Bazı Ekmeklik Buğday Çeşitlerinin Yaprak Hastalıklarına Karşı Reaksiyonlarının Belirlenmesi

    Directory of Open Access Journals (Sweden)

    Nedim Altın

    2017-07-01

    Full Text Available Bu çalışma, Batı Karadeniz Bölgesi Düzce ili ekolojik koşulları altında 19 adet ekmeklik buğday çeşidinin doğal enfeksiyon koşullarında yaprak hastalıklarına karşı reaksiyonlarının belirlenmesi amacıyla yürütülmüştür. Deneme tesadüf blokları deneme desenine uygun olarak 4 tekerrürlü olarak kurulmuş ve ekim işlemi 17.11.2015 tarihinde yapılmıştır. Hastalık gözlemleri ile ilgili çalışmalar; Septoria tritici etmeninin neden olduğu septorya yaprak lekesi hastalığı için süt olum dönemi başlangıcında, Puccinia striiformis etmeninin neden olduğu Sarı Pas hastalığı için çiçeklenme dönemi sonunda, Puccinia recondita etmeninin neden olduğu Kahverengi Pas için süt olum dönemi başlangıcında yapılmıştır. Tarla koşullarında doğal bulaşıklığa göre yapılan değerlendirme sonucunda hastalık oranları belirlenmiştir. Belirlenen hastalık şiddetine göre, septorya yaprak lekesi hastalığına karşı en hassas çeşidin % 60 hastalık şiddeti ile “Bereket”, en tolerant çeşidin ise %14 ile “Aslı” olduğu, Sarı Pas hastalığına karşı en hassas çeşidin %45,4 ile “Tekirdağ”, en tolerant çeşidin %0,6 ile “Midas” olduğu ve Kahverengi Pas hastalığına karşı ise en hassas çeşidin %22 ile “Tahirova” en tolerant çeşidin ise %0,2 ile “Midas” olduğu belirlenmiştir. Çalışma sonucunda elde edilen verilere göre septorya yaprak lekesi hastalığına karşı Aldane, Aslı, Konya 2002, Köprü, Masaccio ve Tosunbey, Sarı Pas hastalığına karşı Aslı, Esperia, Kate A1, Karasunya Odeska, Masaccio ve Midas, Kahverengi Pas hastalığına karşı ise Aldane, Aslı, Bereket, Köprü, Masaccio, Midas ve Tekirdağ çeşitlerinin ileride yapılacak ıslah çalışmaları için ümitvar olduğu görülmüştür.

  18. [Glutamate receptors genes polymorphism and the risk of paranoid schizophrenia in Russians and tatars from the Republic of Bashkortostan].

    Science.gov (United States)

    Gareeva, A E; Khusnutdinova, E K

    2014-01-01

    Schizophrenia is a severe mental disorder that affects about 1% of the world population, leading to disability and social exclusion. Glutamatergic neurotransmission is a violation of one of the main hypotheses put forward to explain the neurobiological mechanisms of schizophrenia. Post mortem studies have found changes in the degree of affinity glutamate receptors, their transcription, and altered expression of their subunits in the prefrontal cortex, hippocampus, and thalamus in patients with schizophrenia. As a result of genetic studies of gene family encoding ionotropic AMPA and kainate glutamate receptors in schizophrenia, ambiguous results were received. The association of polymorphic variants of genes GRIA2 and GRIK2 with paranoid schizophrenia and response to therapy with haloperidol in Russian and Tatar of the Republic of Bashkortostan was conducted in the present study. DNA samples of 257 patients with paranoid schizophrenia and of 349 healthy controls of Russian and Tatar ethnic group living in the Republic of Bashkortostan were involved into the present study. In the result of the present study: (1) high risk genetic markers of paranoid schizophrenia (PSZ) were obtained: in Russians-GR4IA2*CCC (OR = 9.60) and in Tatars-GRIK2*ATG (OR = 3.5), GRIK2*TGG (OR = 3.12) (2) The following low risk genetic markers of PSZ were revealed: in Tatars-GRIA2*T/T (rs43025506) of GRIA2 gene (OR = 0.34); in Russians.- GRIA2*CCT (OR = 0.481). (3) Genetic markers of low haloperido! treatment efficacy in respect of negative and positive symptoms GRIK2*T/T (rs2227281) of GRIK2 gene and GRAL42*C/C in Russians, GRIK2*A/A (rs995640) of GRIK2 gene in Tatars. (4) Genetic markers of low haloperidol treatment efficacy in respect of positive symptoms GRL42*C/C in Russians. The results of the present study support the hypothesis of the involvement of glutamate receptor genes in schizophrenia pathway. Considerable inter-ethnic'diversity of genetic risk factors for this disease was

  19. Glutamate Receptors in the Central Nucleus of the Amygdala Mediate Cisplatin-Induced Malaise and Energy Balance Dysregulation through Direct Hindbrain Projections.

    Science.gov (United States)

    Alhadeff, Amber L; Holland, Ruby A; Nelson, Alexandra; Grill, Harvey J; De Jonghe, Bart C

    2015-08-05

    Cisplatin chemotherapy is used commonly to treat a variety of cancers despite severe side effects such as nausea, vomiting, and anorexia that compromise quality of life and limit treatment adherence. The neural mechanisms mediating these side effects remain elusive despite decades of clinical use. Recent data highlight the dorsal vagal complex (DVC), lateral parabrachial nucleus (lPBN), and central nucleus of the amygdala (CeA) as potential sites of action in mediating the side effects of cisplatin. Here, results from immunohistochemical studies in rats identified a population of cisplatin-activated DVC neurons that project to the lPBN and a population of cisplatin-activated lPBN calcitonin gene-related peptide (CGRP, a marker for glutamatergic neurons in the lPBN) neurons that project to the CeA, outlining a neuroanatomical circuit that is activated by cisplatin. CeA gene expressions of AMPA and NMDA glutamate receptor subunits were markedly increased after cisplatin treatment, suggesting that CeA glutamate receptor signaling plays a role in mediating cisplatin side effects. Consistent with gene expression results, behavioral/pharmacological data showed that CeA AMPA/kainate receptor blockade attenuates cisplatin-induced pica (a proxy for nausea/behavioral malaise in nonvomiting laboratory rodents) and that CeA NMDA receptor blockade attenuates cisplatin-induced anorexia and body weight loss in addition to pica, demonstrating that glutamate receptor signaling in the CeA is critical for the energy balance dysregulation caused by cisplatin treatment. Together, these data highlight a novel circuit and CGRP/glutamatergic mechanism through which cisplatin-induced malaise and energy balance dysregulation are mediated. To treat cancer effectively, patients must follow prescribed chemotherapy treatments without interruption, yet most cancer treatments produce side effects that devastate quality of life (e.g., nausea, vomiting, anorexia, weight loss). Although hundreds of

  20. Glutamate Receptors in the Central Nucleus of the Amygdala Mediate Cisplatin-Induced Malaise and Energy Balance Dysregulation through Direct Hindbrain Projections

    Science.gov (United States)

    Alhadeff, Amber L.; Holland, Ruby A.; Nelson, Alexandra; Grill, Harvey J.

    2015-01-01

    Cisplatin chemotherapy is used commonly to treat a variety of cancers despite severe side effects such as nausea, vomiting, and anorexia that compromise quality of life and limit treatment adherence. The neural mechanisms mediating these side effects remain elusive despite decades of clinical use. Recent data highlight the dorsal vagal complex (DVC), lateral parabrachial nucleus (lPBN), and central nucleus of the amygdala (CeA) as potential sites of action in mediating the side effects of cisplatin. Here, results from immunohistochemical studies in rats identified a population of cisplatin-activated DVC neurons that project to the lPBN and a population of cisplatin-activated lPBN calcitonin gene-related peptide (CGRP, a marker for glutamatergic neurons in the lPBN) neurons that project to the CeA, outlining a neuroanatomical circuit that is activated by cisplatin. CeA gene expressions of AMPA and NMDA glutamate receptor subunits were markedly increased after cisplatin treatment, suggesting that CeA glutamate receptor signaling plays a role in mediating cisplatin side effects. Consistent with gene expression results, behavioral/pharmacological data showed that CeA AMPA/kainate receptor blockade attenuates cisplatin-induced pica (a proxy for nausea/behavioral malaise in nonvomiting laboratory rodents) and that CeA NMDA receptor blockade attenuates cisplatin-induced anorexia and body weight loss in addition to pica, demonstrating that glutamate receptor signaling in the CeA is critical for the energy balance dysregulation caused by cisplatin treatment. Together, these data highlight a novel circuit and CGRP/glutamatergic mechanism through which cisplatin-induced malaise and energy balance dysregulation are mediated. SIGNIFICANCE STATEMENT To treat cancer effectively, patients must follow prescribed chemotherapy treatments without interruption, yet most cancer treatments produce side effects that devastate quality of life (e.g., nausea, vomiting, anorexia, weight loss

  1. S-18: Futbol ve Hentbolcuların Fonksiyonel Hareket Değerlendirme Test Sonuçlarının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Ahmet Bayrak

    2017-03-01

    Full Text Available AMAÇ: Functional Movement Screen(FMS(fonksiyonel hareket değerlendirme, sporcularda hareket kapasitesini ve yaralanma riskini değerlendirmek amacıyla kullanılan bir test bataryasıdır. Bu çalışma; profesyonel farklı iki spor branşındaki (Futbol ve hentbol sporcuların yaralanma riskini FMS skorları ile belirlemek ve farklı iki branşın yaralanma riskini karşılaştırmak amacı ile yapıldı. YÖNTEM: Çalışmaya Konya Spor U19 takımından 22 futbolcu ve Selçuklu Belediye Spor Hentbol takımından 24 hentbol sporcusu dahil edildi. Sporculara çalışma öncesi onam formları imzalatıldı ve çalışma hakkında bilgi verildi. Sporcularda yedi temel hareket (hurdle step, inline lunge, shoulder mobility, trunk pushup, deepsquat, activestraightlegraise, rotatorystability değerlendirildi ve bu hareketler 1-2-3 puanlama sistemine göre puanlandı. Değerlendirme esnasında çift kamera kullanılarak görüntüler analiz edildi. Yapılan puanlama sonucu çıkan veriler değerlendirilirken; FMS skoru yaralanma riski için cut off değeri 14 alındı. Sağ ve sol ölçümler için ortalaması alınarak toplama dahil edildi. Asimetri belirlenirken her bir test için bireysel skorların sağ ve sol farkı alınarak, bir ve daha yukarısı için asimetri var; fark sıfır ise asimetri yok olarak kodlandı. FMS skorlarının gruplar arasında toplam ve ortalamalarının karşılaştırılmasında bağımsız t testi kullanıldı. Kategorik değişkenler için ki-kare ve 2x2 tablolar için Fisher’sExact uygulandı ve odds oranları hesaplandı.BULGULARYapılan analiz sonucunda hentbol oyuncularının futbol oyuncularına göre 4,2 kat daha fazla yaralanma riski taşıdıkları saptandı (p>0.05. Alt parametreleri değerlendirildiğinde, sağ ve sol asimetrisi, shoulder mobility testi ve inline lunge asimetrisi için iki grup arasında ile anlamlı bir fark bulundu(p0.05. TARTIŞMA VE SONUÇ22 futbol oyuncusu ve 24 hentbol oyuncusu ile

  2. apılan Sporun Karakteristiği Solunum Fonksiyonlarını Etkiler mi? Voleybol ve Judo Sporcularının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Tuğba KOCAHAN

    2017-06-01

    Full Text Available Sporcular yapılan spora bağlı olarak farklı fizyolojik adaptasyonlar geliştirirler. Solunum fonksiyonları da bu adaptasyonlardan etkilenir. Çalışmamızın amacı karakteristiği birbirinden oldukça farklı olan voleybol ve judo sporunun solunum fonksiyonları üzerindeki etkisini karşılaştırmaktır. Çalışmaya ortalama yaşı 15,50±1,08 yıl olan 12 erkek voleybol sporcusu ile ortalama yaşı 15,10±1.37 yıl olan 10 erkek judo sporcusu dahil edildi. Sporcuların solunum fonksiyonları spirometre ile test edildi. Sporcuların forced expiratory volume-zorlu ekspiratuar hacim (FEV, forced expiratory volume in one second-bir saniyedeki zorlu ekspiratuar hacim (FEV1, forced vital capasity- zorlu vital kapasite (FVC, forced ekspiratuary volume-zorlu ekspiraturar volüm/ forced vital capasity-zorlu vital kapasite yüzdesi (FEV1/FVC%, peak expiratory flow- tepe akım hızı (PEF, forced expiratory volume at %25- %25’deki zorlu ekspiratuar hacim (FEV25, forced expiratory volume at %50- %50’deki zorlu ekspiratuar hacim (FEV50, forced expiratory volume at %75- %75’deki zorlu ekspiratuar hacim (FEV75 değerleri kaydedildi ve SPSS istatistiksel analiz programı kullanılarak veriler karşılaştırıldı. Sporcuların yaşları arasında anlamlı bir fark bulunamamıştır (p>0,05. Boy ve kilo değerleri arasında anlamlı bir fark mevcut olsa da söz konusu bu fark BKI (Beden Kitle İndeksi için geçerli değildir (p>0,05. Spirometrik değişkenlerden FEV1/FVC% haricindeki tüm değerler voleybol sporcularında daha yüksek belirlenmiştir ve iki grup arasındaki değişkenler arasındaki farkın tamamı anlamlılık düzeyine ulaşmıştır (p<0,05. Voleybol sporunda, judo sporuna kıyasla solunum sistemi üzerine düşen yükün daha fazla olması bu sporcuların solunum fonksiyonlarının judo sporcularından yüksek çıkmasına sebep olmuştur. Bu çalışma ile yapılan sporun karakteristiğinin solunum sistemi

  3. İzmir Merkez İlçelerindeki Akvaryum İşletmelerinin Genel Profilinin Çıkarılması Üzerine Bir Araştırma.

    Directory of Open Access Journals (Sweden)

    Müge A. Hekimoğlu

    2015-12-01

    Full Text Available Bu araştırmada, İzmir merkez ilçelerindeki akvaryum işletmelerinin profili çıkarılarak, genel durumları hakkında değerlendirmeler amaçlanmıştır. Çalışmada öncelikle, İzmir`deki mevcut akvaryum işletmelerinin sayısal durumunun tespiti yapılıp; işletmelerin pazarladıkları ürünler belirlenmiş ve gelecekteki pazar durumu hakkında tahminde bulunulmuştur. İzmir ilinde yer alan akvaryum işletmeleriyle doğrudan görüşmeler yoluyla gerçekleştirilen araştırmanın orijinal verileri hazırlanmıştır. Anket çalışmasına temel oluşturan İzmir ilinde bulunan akvaryum işletmeleri ana kitle olarak kabul edilerek tam sayım yöntemi kullanılmıştır. Anket sonuçları SPSS ( The Statistical Package for The Social Sciences paket programı yardımıyla değerlendirilmiştir. Çalışmada belirlenen tüm akvaryum işletmelerinden %65’nin halen faaliyette olduğu, %35’inin ise kapandığı tespit edilmiştir. Halen çalışan akvaryum işletmelerinin %38,2`si Konak, %23,5`u Bornova, %17,6’sı Karşıyaka ve %21,6`sı Buca ve Narlıdere’de bulunmaktadır. Bugüne kadar bu işletmelerin % 82`si üniversiteden danışmanlık almışlardır. Bu akvaryum işletmelerinin %94`ü şahıs işletmesi ve %6’sı ticaret ortaklığıdır, bunun yanında bu işletmelerde çalışanların %94`ü erkek ve çalışanların %59`u lise mezunudur. Araştırma sonunda akvaryumcuların sorunları belirlenerek çözüm önerileri ortaya konulmaya çalışılmıştır

  4. Sınıflandırma Problemlerinin Karşılaştırılmasında ANFIS ve Basamak Korelasyon Sinir Ağının Kullanımı

    Directory of Open Access Journals (Sweden)

    Nilgün ŞENGÖZ

    2016-11-01

    Full Text Available Yapılan bu çalışmada, sınıflandırma problemleri üzerinde durulmuştur. Bu çalışma farklı yapıda olan 3 adet veri kümesinin (Tohum, Arazi Uydu Görüntüleme ve Kırmızı Şarap Kalite Değerlendirme incelenmesi ve aynı algoritmaların bu verilere uygulanması itibariyle hem başarı performansı olarak hem de zaman bakımından aralarındaki ilişkiyi gözler önüne sermektedir. Tohum verisi için yapılan karşılaştırmada Uyarlamalı ağ tabanlı bulanık çıkarım sistemi (Adaptive-Network Based Fuzzy Inference Systems-ANFIS  ile Basamak Korelasyon Sinir Ağı BKSA (Cascade Correlation Neural Network-CCNN test performans yüzdeleri %86.41 ve %88.06 olup, işlem zamanı yönünden bakıldığında ise BKSA  0.59 saniye gibi kısa bir süre içerisinde sınıflandırma yapmıştır.  Arazi Uydu Görüntüleme veri kümesinde ise test performans yüzdeleri ANFIS de %100, BKSA da ise %99.92 olmaktadır. Verinin algoritma içerisinde yaptığı işlem süreleri ise ANFIS 800 saniye, BKSA 72 saniyede tüm sınıflandırma işlemini tamamlamıştır. Son veri kümemiz ise Kırmızı Şarap Kalite değerlendirmedir ve test performans olarak bakıldığında ANFIS %99.975, BKSA ise %99.862 gibi birbirleri arasında çokta anlamlı bir fark oluşturmadığı açıkça görünmektedir. İşlem zamanı bakımından ANFIS 85.271 saniye ile BKSA metoduna göre çok hantal kalmaktadır.

  5. Monzonitoid magmatism of the copper-porphyritic Lazurnoe deposit (South Primor'e): U-Pb and K-Ar geochronology and peculiarities of ore-bearing magma genesis by the data of isotopic-geochemical studies

    Science.gov (United States)

    Sakhno, V. G.; Kovalenko, S. V.; Alenicheva, A. A.

    2011-05-01

    Magmatic rocks from the copper-porphyritic Lazurnoe deposit (Central Primor'e) have been studied. It has been found that rocks from the Lazurnyi massif are referred to gabbro-monzodiorites, monzodiorites, and monzo-granodiorites formed during two magmatic phases of different ages. The earlier phase is represented by gabbro-monzodiorites and diorites of the North Stock, and the later one, by gabbro-monzodiorites and monzo-grano-diorites of the South Stock. On the basis of isotopic dating by the U-Pb (SHRIMP) method for zircon and by the K-Ar method for hornblendes and biotites, the age of magmatic rocks is determined at 110 ± 4 for the earlier phase and at 103.5 ± 1.5 for the later one. Examination of the isotopic composition for Nd, Sr, Pb, Hf, δ18O, and REE spectra has shown that melts of the first phase are contaminated with crustal rocks and they are typical for a high degree of secondary alterations. Potassiumfeldspar, biotite, propylitic alterations, and sulfidization are manifested in these rocks. The rocks of the later stage of magmatism are characteristic for a primitive composition of isotopes and the absence of secondary alterations. They carry the features of adakite specifics that allows us to consider them derivatives of mantle generation under high fluid pressure. The intrusion of fluid-saturated melts of the second phase into the magmatic source of the first phase caused both an alteration pattern of rocks and copper-porphyritic mineralization. Isotopes of sulfur and oxygen allow us to consider the ore component to be of magmatic origin.

  6. Kafkasya Muhacirlerinin Suriye Vilayetine İskânı ve Karşılaşılan Zorluklar The Settlement of Caucasian Refugees to Syria Province and the Hardships Encountered

    Directory of Open Access Journals (Sweden)

    Oktay KIZILKAYA

    2013-03-01

    ı-RusSavaşı sonucunda Osmanlı Devleti savaşı kaybetti. Savaş neticesindeOsmanlı Devleti Balkan coğrafyası’nda büyük bir toprak parçasıkaybetti. Bundan dolayı daha önce Balkan Coğrafyasına iskân edilenKafkasya muhacirleri yeniden muhacir konumuna düştü. HemKafkasya hem de Rumeli’den gelen göçmenlere yeni iskân bölgesi olarakSuriye Vilayeti uygun görüldü. Suriye Vilayetine gönderilen göçmenlerorada büyük zorluklarla karşılaştı. Doğal şartlar yönünden Suriye’ninhavasına ve suyuna uyum problemi yaşadılar. Buna bakımsızlıktankaynaklanan salgın hastalıklarda eklenince, muhacirlerin yarıya yakınıyaşamını kaybetti. Bunun dışında, bölgedeki Dürzî ve Bedevi Arapaşiretleri ile muhacirler arasında yaşanan toplumsal çatışmalar daeklenince muhacirler büyük sıkıntılarla karşılaştı.Muhacirler, Suriye Vilayetine iskânından yaklaşık otuz yıl sonrabölgenin sosyo-kültürel ve iklim şartlarına uyum sağladılar. Muhacirler,Suriye Vilayetine uyum sağladıktan sonra kendilerine saldırılardabulunan Bedevi ve Dürzîlere karşı daha güçlü hale geldiler.Osmanlı Devleti imkânlarının çok üstünde olan muhacir iskânıkonusunda bütün imkânlarını seferber etti. Buna rağmen istenmeyenolayların yaşanmasına engel olamadı.

  7. Ionotropic crustacean olfactory receptors.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Corey

    Full Text Available The nature of the olfactory receptor in crustaceans, a major group of arthropods, has remained elusive. We report that spiny lobsters, Panulirus argus, express ionotropic receptors (IRs, the insect chemosensory variants of ionotropic glutamate receptors. Unlike insects IRs, which are expressed in a specific subset of olfactory cells, two lobster IR subunits are expressed in most, if not all, lobster olfactory receptor neurons (ORNs, as confirmed by antibody labeling and in situ hybridization. Ligand-specific ORN responses visualized by calcium imaging are consistent with a restricted expression pattern found for other potential subunits, suggesting that cell-specific expression of uncommon IR subunits determines the ligand sensitivity of individual cells. IRs are the only type of olfactory receptor that we have detected in spiny lobster olfactory tissue, suggesting that they likely mediate olfactory signaling. Given long-standing evidence for G protein-mediated signaling in activation of lobster ORNs, this finding raises the interesting specter that IRs act in concert with second messenger-mediated signaling.

  8. Assays for calcitonin receptors

    International Nuclear Information System (INIS)

    Teitelbaum, A.P.; Nissenson, R.A.; Arnaud, C.D.

    1985-01-01

    The assays for calcitonin receptors described focus on their use in the study of the well-established target organs for calcitonin, bone and kidney. The radioligand used in virtually all calcitonin binding studies is 125 I-labelled salmon calcitonin. The lack of methionine residues in this peptide permits the use of chloramine-T for the iodination reaction. Binding assays are described for intact bone, skeletal plasma membranes, renal plasma membranes, and primary kidney cell cultures of rats. Studies on calcitonin metabolism in laboratory animals and regulation of calcitonin receptors are reviewed

  9. Angiotensin type 2 receptor (AT2R) and receptor Mas

    DEFF Research Database (Denmark)

    Villela, Daniel; Leonhardt, Julia; Patel, Neal

    2015-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor Mas are components of the protective arms of the renin-angiotensin system (RAS), i.e. they both mediate tissue protective and regenerative actions. The spectrum of actions of these two receptors and their signalling mechanisms display striki...

  10. “Gülün Adı ve Benim Adım Kırmızı” Adlı Romanlara Karşılaştırmalı Bir Yaklaşım A Comparative Approach to the novels “Name of the Rose and My Name Is Red”

    Directory of Open Access Journals (Sweden)

    Elmas ŞAHİN

    2013-09-01

    similarapproaches or re-interpretations of the original text are closely relatedto comparative literature.In this context, The novels of the Italian writer Umberto Eco's Name of the Rose, from author of our time, (1980 and Orhan Pamuk's My Name is Red (1998 from our modern writer enter to field of literature in different geographies, but have similar themes in the terms of the content and form, they are synchronic samples for comparative literatureThe works Name of the Rose and My Name is Red in this study, using the text-oriented analysis method will be compared in terms of essence and form. Both of these works, by considered similar species, subject matter and motifs, examined in intertextual size, will be resolved by their similarities and differences by the method of comparative literature. Özellikle son yıllarda dünya edebiyatına duyulan ilgi dolayısıyla kültürel çalışmaların da etkisi ile karşılaştırmalı edebiyat popüler bir disiplin olarak karşımıza çıkar. Günümüzde eleştiri ve kültürel çalışmalarla başa baş gitmeye başlayan karşılaştırmalı çalışmaların; ulusal edebiyatları uluslar arası boyutlara taşıyarak; gerek kuram ve gerekse uygulamada dünya edebiyatlarının bir noktada buluşmasına zemin hazırladıkları görülür.Bir eserin başka bir eser yada eserlerle ortak konu ve motif bağlamında benzer ve farklılıklarıyla mukayese edilmesi anlamına gelen ″Karşılaştırmalı edebiyat″ terimi, her ne kadar 19. yüzyılda akademik bir disiplin olarak ortaya çıksa da, ″karşılaştırmalı″ (comparative teriminin çıkış noktasının, Platon ve Aristotales'in klasik çağı ile başladığını söylemek yanlış olmaz. Platon ve Aristotale’in şiir ile felsefeyi karşılaştırarak başladıkları karşılaştırmalı söylemler, Horace, Longinus, Dryden, Arnold; Sanctis, Goethe ve Cuiver ile gelişerek 20. yüzyılda akademik boyutta üst seviyeye ulaşır.Batıda Rene Wellek'in The Crisis of Comparative

  11. TLX: An elusive receptor.

    Science.gov (United States)

    Benod, Cindy; Villagomez, Rosa; Webb, Paul

    2016-03-01

    TLX (tailless receptor) is a member of the nuclear receptor superfamily and belongs to a class of nuclear receptors for which no endogenous or synthetic ligands have yet been identified. TLX is a promising therapeutic target in neurological disorders and brain tumors. Thus, regulatory ligands for TLX need to be identified to complete the validation of TLX as a useful target and would serve as chemical probes to pursue the study of this receptor in disease models. It has recently been proved that TLX is druggable. However, to identify potent and specific TLX ligands with desirable biological activity, a deeper understanding of where ligands bind, how they alter TLX conformation and of the mechanism by which TLX mediates the transcription of its target genes is needed. While TLX is in the process of escaping from orphanhood, future ligand design needs to progress in parallel with improved understanding of (i) the binding cavity or surfaces to target with small molecules on the TLX ligand binding domain and (ii) the nature of the TLX coregulators in particular cell and disease contexts. Both of these topics are discussed in this review. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Glutamate receptor ligands

    DEFF Research Database (Denmark)

    Guldbrandt, Mette; Johansen, Tommy N; Frydenvang, Karla Andrea

    2002-01-01

    Homologation and substitution on the carbon backbone of (S)-glutamic acid [(S)-Glu, 1], as well as absolute stereochemistry, are structural parameters of key importance for the pharmacological profile of (S)-Glu receptor ligands. We describe a series of methyl-substituted 2-aminoadipic acid (AA...

  13. Ginkgolides and glycine receptors

    DEFF Research Database (Denmark)

    Jaracz, Stanislav; Nakanishi, Koji; Jensen, Anders A.

    2004-01-01

    Ginkgolides from the Ginkgo biloba tree are diterpenes with a cage structure consisting of six five-membered rings and a unique tBu group. They exert a variety of biological properties. In addition to being antagonists of the platelet activating factor receptor (PAFR), it has recently been shown ...

  14. adrenergic receptor with preeclampsia

    African Journals Online (AJOL)

    User

    2011-05-09

    May 9, 2011 ... due to a post- receptor defect (Karadas et al., 2007). Several polymorphisms have ... the detection of the Arg16Gly polymorphism, overnight digestion at. 37°C with 10 U ..... DW, Wood AJ, Stein CM (2004). Beta2-adrenoceptor ...

  15. Metformin and insulin receptors

    International Nuclear Information System (INIS)

    Vigneri, R.; Gullo, D.; Pezzino, V.

    1984-01-01

    The authors evaluated the effect of metformin (N,N-dimethylbiguanide), a biguanide known to be less toxic than phenformin, on insulin binding to its receptors, both in vitro and in vivo. Specific 125 I-insulin binding to cultured IM-9 human lymphocytes and MCF-7 human breast cancer cells was determined after preincubation with metformin. Specific 125 I-insulin binding to circulating monocytes was also evaluated in six controls, eight obese subjects, and six obese type II diabetic patients before and after a short-term treatment with metformin. Plasma insulin levels and blood glucose were also measured on both occasions. Metformin significantly increased insulin binding in vitro to both IM-9 lymphocytes and MCF-7 cells; the maximum increment was 47.1% and 38.0%, respectively. Metformin treatment significantly increased insulin binding in vivo to monocytes of obese subjects and diabetic patients. Scatchard analysis indicated that the increased binding was mainly due to an increase in receptor capacity. Insulin binding to monocytes of normal controls was unchanged after metformin as were insulin levels in all groups; blood glucose was significantly reduced after metformin only in diabetic patients. These data indicate that metformin increases insulin binding to its receptors in vitro and in vivo. The effect in vivo is observed in obese subjects and in obese type II diabetic patients, paralleling the clinical effectiveness of this antidiabetic agent, and is not due to receptor regulation by circulating insulin, since no variation in insulin levels was recorded

  16. İki Şair: Hâfız–Fuzûli Karşılaştırması Two Poets: The Comparison Between Hafız and Fuzuli

    Directory of Open Access Journals (Sweden)

    Hamdi BİRGÖREN

    2013-09-01

    is going to be seen thatmore comprehensive studies are needed. Klasik Türk edebiyatından bahseden kaynaklar, İran edebiyatının Türk edebiyatına etkisinden söz etmektedirler. Bu etkinin ne boyutlarda olduğunun anlaşılabilmesi için çok yönlü karşılaştırmalara ihtiyaç vardır. Ancak derinlemesine bir araştırma yapmadan Firdevsî, Feridüddin Attar, Nizamî-i Gencevî, Mevlânâ, Sadî, Ömer Hayyam, Hâfız-ı Şîrâzî, Molla Câmî gibi isimleri saymak bile bu etkiye ışık tutacak mahiyettedir. Bu isimlerden Firdevsî’nin Şehnâme, Attar’ın Tezkiretü’l-evliyâ ve Mantıku’t-tayr, Mevlânâ’nın Mesnevî, Sadî’nin Bostan ve Gülistan, Molla Câmî’nin Bahâristan ve Ömer Hayyam’ın rubaileriyle Türk şairleri üzerinde etkili olduğu bilinmekte diğer şairlerin hangi alanda ne kadar etki ettiği pek bilinmemektedir. Bu etkinin anlaşılmasına katkı sağlamak amacıyla biz de Hâfız ile Fuzûlî Divanlarını birkaç açıdan karşılaştırmak istiyoruz.İran edebiyatının büyük gazel şairi Hâfız-ı Şîrâzî ile Türk edebiyatının büyük şairi Fuzûlî arasındaki etkileşimi anlamak için öncelikle bu şairlerin içinde bulundukları sosyal ve siyasi şartlara bir göz atmak yerinde olur sanırız. Sonra bu şairlerin hayatlarına ve edebi şahsiyetlerine değinerek şiirdeki başarılarından söz etmek istiyoruz.Hâfız 14. yüzyılda yaşamış büyük bir İran şairi, Fuzûlî ise 16. yüzyıl Türk edebiyatının büyük şairlerinden biridir. Elbette iki ayrı edebiyatın iki büyük ismini bütün özellikleriyle bir makale çerçevesinde karşılaştırma imkânı olmadığının farkındayız. Bu sebeple genel bir değerlendirmede bulunabilmek için şiirlerinin bazı yönlerine değinecek ve örnek olmak üzere şairlerin birer gazelini ve nesre çevrilmiş biçimini vereceğiz.Yaşadıkları çağlar, kullandıkları diller ve işledikleri konular göz önüne alındığında daha kapsamlı

  17. Metil ve Etil Ester Kullanılan Bir Common-Rail Dizel Motorda Performans, Yanma ve Enjeksiyon Karakteristiklerinin Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Ertan ALPTEKİN

    2017-02-01

    Full Text Available Biyodizel, dünyada kullanımı yaygınlaşan yenilebilir ve alternatif bir dizel yakıtıdır. Biyodizel üretiminde kullanılan alkol büyük önem arz etmekte ve üretilen biyodizelin yakıt özelliklerini doğrudan etkilemektedir. Farklı yakıt özellikleri, dizel motorlarda farklı yakıt enjeksiyon ve yanma karakteristiklerine sebep olabilmektedir. Bu nedenle bu çalışmada, metanol ve etanol kullanılarak üretilen iki farklı ester yakıtı ve saf motorin, common-rail yakıt enjeksiyon sistemine sahip bir dizel motorda üç farklı motor yükü (50 Nm, 100 Nm ve 150 Nm ve 2000 dev/dk sabit motor devrinde deney yakıtı olarak kullanılmıştır. Bu yakıtların performans, yanma ve yakıt enjeksiyon analizi karşılaştırmalı olarak gerçekleştirilmiştir. Deney sonuçlarına göre, etil ve metil ester kullanımıyla özgül yakıt tüketimi (ÖYT motorine kıyasla artış göstermiştir. Etil ve metil ester yakıtlarının silindir içi basıncı ve ısı yayılımı değerleri tüm deney şartlarında motorine kıyasla daha yüksek olmuştur. Yakıt enjeksiyon karakteristikleri, yakıt tipi ve motor yüküne bağlı olarak farklılık göstermiştir.

  18. DBYBHY2007 ve FEMA440 da Önerilen Performans Noktası Belirleme Yaklaşımlarının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Konuralp Girgin

    2013-03-01

    Full Text Available Mevcut betonarme yapı sistemlerinin performansa dayalı hesabında, kapasite ve istem eğrilerinin kesiştirilmesi ile elde edilen performans noktasının belirlenmesi için farklı yaklaşımlar bulunmaktadır. Deprem Bölgelerinde Yapılacak Binalar Hakkında Yönetmelik (DBYBHY2007 de, TB'den daha uzun peryotlu yapılar için eşit yerdeğiştirme prensibine dayalı bir yöntem izlenirken, FEMA440 da efektif periyot ve sönüm tanımlarına dayalı bir ardışık yaklaşım yöntemi önerilmektedir. Bu çalışmada, düzenli betonarme yapı sistemlerini temsil edecek şekilde seçilen, farklı kat sayılarına sahip çerçeve ve perde-çerçeve türü taşıyıcı sistemi olan binalar üzerinde çalışılmıştır. Bu binalar için DBYBHY2007 ve FEMA440 da tanımlanan performans noktası belirleme yaklaşımları kullanılarak elde edilen deprem istemleri, birbirleriyle ve "kesin çözüm" olarak kabul edilen Zaman Tanım Alanında Doğrusal Olmayan Analiz (ZTADOA ile bulunan deprem istemleriyle karşılaştırılmıştır. Bu istemler arasında tepe yerdeğiştirmesi, taban kesme kuvveti, göreli kat ötelemeleri bulunmaktadır. İncelenen sistemlerde, DBYBHY2007 ile belirlenen istemlerin "kesin çözüm" olarak kabul edilen ZTADOA sonuçlarına daha yakın olduğu gözlenmiştir.

  19. Türkiye’nin Farklı Coğrafik Bölgelerinden Toplanan Propolis Örneklerinin Aspergillus versicolor ve Penicillium aurantiogriseum’e Karşı Antifungal Aktiviteleri (İngilizce

    Directory of Open Access Journals (Sweden)

    Ayhan Temiz

    2015-02-01

    Full Text Available Bu çalışmanın amacı, Türkiye’nin çeşitli coğrafik bölgelerinden toplanan 10 propolis örneğinin mikotoksin üreticisi olan, gıda kaynaklı iki küf (Aspergillus versicolor ve Penicillium aurantiogriseum suşuna karşı antifungal aktivitelerini araştırmaktır. Propolis örneklerinin etil alkol ekstraktlarının (EEP kimyasal kompozisyonları kütle spektorometresine birleştirilmiş gaz kromatografisi ile belirlenmiştir. EEP örneklerinin antifungal aktiviteleri %1, %5 ve %10 olacak şekilde üç farklı konsantrasyonda test edilmiştir. EEP örneklerinin antifungal aktiviteleri, incelenen küf suşunun Patates Dekstroz Agar besiyeri yüzeyindeki misel gelişiminde meydana gelen inhibisyonun yüzdesi şeklinde belirlenmiştir. EEP örneklerinin ana bileşenleri flavonoitler, aromatik alkoller, aromatik asit esterler, alifatik asit esterler, aromatik asitler, alkoller ve aromatik hidrokarbonlar olarak tespit edilmiştir. EEP örneklerinin tümü %10 konsantrasyonda her iki küf suşunun misel gelişimi üzerinde %100 inhibisyon sağlamıştır. EEP örneklerinin iki küf suşu üzerindeki antifungal etkisi %1 ve %5 konsantrasyonlarında değişkenlik göstermiştir. Araştırma sonuçları, P. aurantiogriseum suşunun misel gelişimi üzerinde inhibisyon etkisi yaratması için A. versicolor’a kıyasla daha yüksek bir EEP konsantrasyonuna gereksinim olduğuna işaret etmektedir. Küf suşları üzerinde etkin olan propolis örneklerinin flavonoit yüzdesi diğer bileşenlerin yüzdesinden oldukça daha yüksektir. Bu sonuçlar, propolis örneklerinin EEP konsantrasyonuna ve kimyasal kompozisyonuna bağlı olarak iki küf suşu üzerinde de belirgin kuvvette bir antifungal etki yarattığına işaret etmektedir.

  20. New Constraints for Tectono-Thermal Alpine Evolution of the Pyrenees: Combining Zircon Fission-Track and (U-Th)/He Analyses with Raman Spectrometry and In-Situ K-Ar Geochronology

    Science.gov (United States)

    Waldner, M.; Bellahsen, N.; Mouthereau, F.; Pik, R.; Bernet, M.; Scaillet, S.; Rosenberg, C.

    2017-12-01

    The pyrenean range was formed by the convergence of European and Iberian plates following the inversion of the Mesozoic rifting in the north of Pyrenees. In the Axial Zone, the collision caused an antiformal nappe-stacking of tectonic units. Recent studies pointed out the importance of pre-collision structural and thermal inheritance that may play a major role for orogeny such as: 1) Paleozoic Variscan inheritance; 2) Mesozoic rift-related high geothermal gradients, which are maintained during the onset of convergence in the North Pyrenean Zone. From a mineralogical point of view, pre-collision feldspars have been destabilized and influenced the development of alpine phyllonite in brittle-ductile conditions which suggests a weak crustal behavior during the formation of the orogenic wedge. Our aim is to get a better understanding of alpine deformation and exhumation by coupling different thermochronological, geochronological and thermometric methods. We document the thermal evolution of each tectonic unit by using low-temperature thermochronometers (Zircon Fission Tracks, U-Th/He on zircons including laser ablation profiles). Our data on vertical profiles combined to existing dataset on apatite allows to model alpine exhumation across the Axial zone. Structural observations through alpine thrusts coupled to geochronology (in situ K/Ar on phengites), Raman and chlorite-phengite thermo(baro)metry provide new key data to unravel the alpine evolution of the Pyrenees. According to preliminary ZFT results on granite massifs in the central part of Pyrenean Axial zone (near ECORS profile), exhumation ages potentially indicates a migration of exhumation towards the south. Exhumation ages of the northern massifs seems to have preserved the North Pyrenean Cretaceous rift evolution. Further south, the onset of exhumation is as old as Paleocene, which precedes the Eocene ages of the literature. The low burial estimated in the northern massifs may indicate a high thermal gradient

  1. Zihin Kuramı: Otizm Spektrum Bozukluğu Olan ve Normal Gelişen Çocukların Performanslarının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Bahar KEÇELİ KAYSILI

    2013-01-01

    Full Text Available Nedensel karşılaştırma deseni kullanılarak planlanan bu araştırmada, otizm spektrum bozukluğu (OSB olan ve normal gelişen (NG çocukların, zihin kuramı performansları ve bu alandaki performansların genel dil ve kronolojik yaşla ilişkisi incelenmiştir. Araştırma grubunu, Türkçe Erken Dil Gelişimi Testi (TEDİL ifade edici dil eşdeğer yaşları en az 4 olan 30 OSB olan ve 30 NG çocuk oluşturmuştur. OSB olan ve NG çocuklar ortalama sözce uzunluğuna (OSU göre eşleştirilmişlerdir. Zihin kuramı becerileri bir grup işlemle değerlendirilmiştir. Araştırma sonuçları, dilde OSU’ ya göre eşleştirilen OSB olan çocuklarla NG çocukların zihin kuramı performanslarının benzer olduğunu, her iki grupta da dilin, zihin kuramı ile ilişkili olduğunu ancak NG çocuklarda dile ek olarak kronolojik yaşın da zihin kuramı ile ilişkili olduğunu göstermiştir. This study examined the theory of mind (ToM performance and the relationship between language, chronological age and theory of mind in children with autism spectrum disorders (ASD and in typically developing (TD children by utilizing the ex-post-facto design. The participants were 30 children with ASD and 30 TD children whose Test of Early Language Development (TELD - Turkish Version expressive language age scores were at least 4 years old. Children with ASD and TD children were matched on mean length of utterance (MLU. ToM ability was assessed on a battery of tasks that have developmental sequence. The findings revealed that the children with ASD and TD children who were matched according to MLU, performed similarly on ToM tasks. Besides language was related to the performance on ToM tasks in children with ASD and in TD children whereas also chronological age is related to the performance on ToM tasks in TD children.

  2. Timing and implications for the late Mesozoic geodynamic settings of eastern North China Craton: Evidences from K-Ar dating age and sedimentary-structural characteristics records of Lingshan Island, Shandong Province

    Science.gov (United States)

    Li, Jie; Jin, Aiwen; Hou, Guiting

    2017-12-01

    The Lingshan Island in Shandong Province in the eastern North China Craton, well known for the Late Mesozoic multi-scale slide-slump structures is related to paleo-earthquake. Terrigenous clastic rocks, volcanic clastic rocks and volcanic lavas are extensively exposed in the Lingshan Island and its adjacent regions of the Shandong Province, which led to fierce debates on their ages, sedimentary characteristics and tectono-sedimentary evolution. In this contribution, we present the characteristics of the Late Mesozoic stratigraphy in the Lingshan Island. Whole-rock K-Ar dating of dyke at Beilaishi and rhyolites at Laohuzui of the Lingshan Island yielded ages of 159 Ma and 106-92 Ma which coincides with the Laiyang Period rifting and the Qingshan Period rifting in the Jiaolai Basin, respectively. On the basis of the analysis to the Late Mesozoic sedimentary environment of `flysch' and `molasse'-like formations as well as tectonic stress fields reconstruction, four episodes of the tectono-sedimentary evolution were established in the Lingshan Island and its adjacent regions in the eastern North China Craton. They consist of two episodes of extensional events for the syn-rift, and two episodes of compression events for the inversion of the post-rift. The entire episodes can be summarized as follows: (1) the first syn-rift NW-SE extension in Laiyang Period can be identified by the `flysch' formation (Unit 1) and by emplacement of the NE-trending dyke in the Laiyang Group. This syn-rift episode can be related to the NW-SE post-orogenic extension resulted from the gravity collapse of the thickened lithosphere along the Sulu Orogen. (2) The first post-rift NW-SE inversion, which was caused by the NW-directed subduction of Izanaqi Plate, can be well documented by the `X' type conjugate joints as well as slide slump folds in Unit 1. (3) The second syn-rift NW-SE extension in Qingshan Period is characterized by rhyolite rocks (Unit 2). This syn-rift episode can be considered

  3. Olfactory Receptor Database: a sensory chemoreceptor resource

    OpenAIRE

    Skoufos, Emmanouil; Marenco, Luis; Nadkarni, Prakash M.; Miller, Perry L.; Shepherd, Gordon M.

    2000-01-01

    The Olfactory Receptor Database (ORDB) is a WWW-accessible database that has been expanded from an olfactory receptor resource to a chemoreceptor resource. It stores data on six classes of G-protein-coupled sensory chemoreceptors: (i) olfactory receptor-like proteins, (ii) vomeronasal receptors, (iii) insect olfactory receptors, (iv) worm chemoreceptors, (v) taste papilla receptors and (vi) fungal pheromone receptors. A complementary database of the ligands of these receptors (OdorDB) has bee...

  4. Prostaglandin Receptor Signaling in Disease

    Directory of Open Access Journals (Sweden)

    Toshiyuki Matsuoka

    2007-01-01

    Full Text Available Prostanoids, consisting of the prostaglandins (PGs and the thromboxanes (TXs, are a group of lipid mediators formed in response to various stimuli. They include PGD2, PGE2, PGF2α, PGI2, and TXA2. They are released outside of the cells immediately after synthesis, and exert their actions by binding to a G-protein coupled rhodopsin-type receptor on the surface of target cells. There are eight types of the prostanoid receptors conserved in mammals from mouse to human. They are the PGD receptor (DP, four subtypes of the PGE receptor (EP1, EP2, EP3, and EP4, the PGF receptor (FP, PGI receptor (IP, and TXA receptor (TP. Recently, mice deficient in each of these prostanoid receptors were generated and subjected to various experimental models of disease. These studies have revealed the roles of PG receptor signaling in various pathological conditions, and suggest that selective manipulation of the prostanoid receptors may be beneficial in treatment of the pathological conditions. Here we review these recent findings of roles of prostanoid receptor signaling and their therapeutic implications.

  5. Stress og hjerte-kar-sygdom

    DEFF Research Database (Denmark)

    Ebstrup, Jeanette Frost; Jørgensen, Torben

    2012-01-01

    Risk factors of cardiovascular disease (CVD) have been studied intensely since the 1950s. Results on stress as a risk factor for CVD have been inconsistent, but mainly positive. The risk is mediated through lifestyle, but more direct physiological mechanisms (e.g. autonomous nervous system...... and hypothalamic-pituitary-adrenal axis) are also found. Personality and general coping resources influence stress-appraisal, stress-coping and stress-response. Future studies should integrate stress as a cause (stressor), as a subjective reaction (perception), and as a physiological reaction in the same...

  6. On Education and Politics / Karlis Streips

    Index Scriptorium Estoniae

    Streips, Karlis

    2011-01-01

    5. septembril ilmunud ajalehes Diena kontrolliti Läti poliitikute teadmisi. Küsimustele vastasid Valdis Zatlers, Solvita Aboltina, Nils Usakovs, Raimonds Vejonis, Ainars Slesers ja Gaidis Berzins. Keskharidusega Ainars Slesersi vastustest. Autor leiab, et keskharidusega inimene ei tohiks parlamendis olla

  7. Stress og hjerte-kar-sygdom

    DEFF Research Database (Denmark)

    Ebstrup, Jeanette Frost; Jørgensen, Torben

    2012-01-01

    and hypothalamic-pituitary-adrenal axis) are also found. Personality and general coping resources influence stress-appraisal, stress-coping and stress-response. Future studies should integrate stress as a cause (stressor), as a subjective reaction (perception), and as a physiological reaction in the same...

  8. Maksukorralduse uurimata imidž / Karlis Goldstein

    Index Scriptorium Estoniae

    Goldstein, Karlis

    2007-01-01

    Uurimusest maksukorralduse imago tõstmise, maksude kogumise ja nende kasutamise vahele seoste tekitamise vajalikkusest. Avalike allikate funktsioonidest maksukorralduse maine käsitlemisel ning trükimeedia ja erakondade programmilistest hinnangutest. Lisa: Autori CV. Tabelid: Ajalehtedes kasutatud maksuteemaliste sõnade positiivsus (jaanuar 2002-aprill 2005); Erakondade programmides kasutatud maksuteemaliste sõnade positiivsus; Küsimustiku tulemused üksikute sõnade kaupa

  9. Oh, for God's Sake! / Karlis Streips

    Index Scriptorium Estoniae

    Streips, Karlis

    2011-01-01

    Valdis Zatlersi Reformierakonnast on 6 parlamendiliiget välja astunud, mis tähendab, et koalitsioonil ei ole enam enamust parlamendis. Autor leiab, et koalitsioon võiks alustada läbirääkimisi parlamendivalimised võitnud venemeelse parteiga Üksmeele Keskus ning Valdis Zatlersi parteist välja astunud võiks ka parlamendist lahkuda

  10. Hey, Dude, Wanna Come Over? / Karlis Streips

    Index Scriptorium Estoniae

    Streips, Karlis

    2010-01-01

    Läti president Valdis Zatlers ei ole saanud ametlikku kutset osaleda 9. mail Moskvas Teise maailmasõja lõppemise 65. aastapäevale pühendatud üritustel. Autor leiab, et Läti vajab normaalseid suhteid Venamaaga

  11. Albino Farelerde Paraben Toksisitesine Karşı Urtica Dioica L. (Urticaceae Özütünün Koruyucu Rolünün Araştırılması

    Directory of Open Access Journals (Sweden)

    Emine YALÇIN

    2016-09-01

    Full Text Available Özet. Bu çalışmada parabenin (hidroksibenzoik asit (HBA albino farelerde bazı biyokimyasal parametreler üzerine etkisi incelenmiştir. HBA’nın toksik etkisine karşı ısırgan otu özütü koruyucu madde olarak seçilmiş ve tüm uygulama gruplarına iki doz halinde uygulanmıştır. Bu kapsamda bir grupta 6 albino fare (Mus musculus, 12-14 haftalık, 25-30 g olmak üzere 6 uygulama grubu oluşturulmuştur.  Çalışma süresince I. gruba pellet yem ve çeşme suyu, II. gruba 125 mg/kg.ca dozunda ısırgan otu özütü, III. gruba 250 mg/kg.ca dozunda ısırgan otu özütü, IV. Gruba 150 mg/kg.ca dozunda HBA, V. gruba 150 mg/kg.ca dozunda HBA + 125 mg/kg.ca dozunda ısırgan otu özütü, VI. gruba 150 mg/kg.ca dozunda HBA + 250 mg/kg.ca dozunda ısırgan otu özütü verilmiştir. Uygulama süresi sonunda farelerin kan örnekleri alınarak serum örnekleri elde edilmiştir. Serum örneklerinde Alanintransaminaz (ALT, Aspartattransaminaz (AST, kan üre azotu (BUN ve kreatinin parametreleri incelenmiştir. Ayrıca her uygulama grubuna ait karaciğer ve böbrek dokuları izole edilmiş ve GSH, MDA analizleri gerçekleştirilmiştir. Çalışma sonucunda HBA uygulanan gruplarda serum ALT, AST, BUN ve kreatinin plazma seviyelerinde önemli değişmeler gözlenmiştir. Bu değişimler HBA’nın hücreler üzerindeki muhtemel toksik etkileri ile açıklanabilir. Benzer şekilde HBA uygulanan gruplarda kontrol grubuna kıyasla MDA seviyelerinde artış gözlenirken, GSH seviyelerinde azalmanın olduğu tespit edilmiştir. HBA ile birlikte ısırgan otu özütü uygulanan gruplarda test edilen parametrelerde yeniden düzelme olduğu belirlenmiştir. Bu sonuçlar ısırgan otu özütünün HBA toksisitesine karşı koruyucu etkisini ortaya koymaktadır.Anahtar Kelimeler: Paraben, Isırgan otu özütü, ALT, AST Abstract. In this study effects of paraben (hydroxybenzoicacid (HBA on some biochemical parameters in albino mice were investigated

  12. Attempts of whole-rock K/Ar dating of mesozoic volcanic and hypabissal igneous rocks from the Central Subbetic (Southern Spain: A case of differential Argon loss related to very low-grade metamorphism

    Directory of Open Access Journals (Sweden)

    Sanz de Galdeano, C.

    1988-04-01

    Full Text Available 12 samples of basic intrusives within Triassic rocks «ophites» and 11 samples of volcanic and associated intrusives within Jurassic to Early Cretaceous sequences of the Subbetic Zone were subjected to whole-rock K/Ar dating in combination with chemical/petrological analysis. Satisfactory results were obtained only from a number of samples of volcanic rocks, however, analytical ages commonly agree, within about 10 relative percent, with those deduced from stratigraphic location. «Ophite» samples, on the other hand, may reveal considerably lower analytic ages than the volcanics and show much stronger scattering, even among samples collected within a small area. It is argued that the inferred loss of Ar results from very-low-grade alpine metamorphic alteration, which affected the «ophites» more intensely than the higher volcanic rocks. Other post-emplacement chemical changes, such as the degree of secondary oxidation of Fe, are also distintive among the two groups of samples, and are to some extent consistent with the above view in that the alteration environment of the ophites should have produced conditions for more penetrative fluid-rock interactions and homogeneous recrystallization. Overall, the magmatic activity from which the ophitic rocks originated might have started in the Late Triassic and continued in the Lower Jurassic. 80th, the «ophites» and the volcanics are though to be the result of magmatic events Collowing tensional to transtensive crustal movements affecting the external basins of the Betic Cordilleras Crom Late Triassic to Early Cretaceous times.Doce muestras de cuerpos básicos intrusivos en rocas triásicas («ofitas» y 11 muestras de volcanitas y rocas intrusivas asociadas en secuencias jurásico-cretáceas de la zona Subbética han sido objeto de datación radiométrica K/Ar (roca total en combinación con análisis químico-petrográfico. Las edades analíticas obtenidas son 's

  13. Tüketim, Tüketim Toplumu ve Tüketim Kültürü: Karşılaştırmalı Bir Analiz / Consumption, Consumption Society and Consumption Culture: A Comparative Analysis

    Directory of Open Access Journals (Sweden)

    Olkan SENEMOĞLU

    2017-05-01

    Full Text Available Bu makale, tüketim, tüketim toplumu ve tüketim kültürü kavramlarına odaklanmak¬tadır. Bu kavramların literatürde nasıl tanımlandığına değinerek, karşılaştırmalı bir analizi¬ni sunmayı amaçlamaktadır. Ayrıca bu makalede tüketim olgusu başta olmak üzere, tüketim toplumu ve tüketim kültürünün günümüzde ne ifade ettiğine odaklanılmaktadır. Bu bağlamda ihtiyaçların manipülasyonu tezi, gösteri toplumu kuramı, reklamın bir tüketim propagandası olduğu yönündeki iddia ve tüketimin fazla ürüne sahip olmayla herhangi bir bağlantısının olmadığını ileri süren düşünce ele alınmaktadır. Tüketim olgusunun iktisadi, sosyal ve kültürel olmak üzere çeşitli boyutlarını ele alan literatürün karşılaştırmalı bir analizi üzerine kurulan bu çalışmada, sadece bir şeyler satın almanın insanları tüketici yapmadığına, insanın ihti¬yacına tekabül eden nesneleri tüketmesinin onu tüketiciye dönüştürmediğine değinilmektedir. Tüketim toplumunda, tüketimin artık ihtiyaçtan dolayı gerçekleşmediğine aksine bizzat tüketi¬min kendisinin bir ihtiyaç haline geldiğine odaklanılmaktadır. Böyle olduğu için de insanların artık kültür yaratmadıklarına “tüketim kültürü”nün nesnelerine eklemlenerek kendilerini var ettiklerine dikkat çekilmektedir. Bu doğrultuda genel olarak çağımızın artık tüketim kültürü¬nün hüküm sürdüğü bir çağ olduğu iddia edilmektedir. Bireyin artık tüketimle, kültürüne dair bir ifade biçimi ortaya koymadığı tam tersine artık tüketim nesnesinin kendisinin birey için bir imaj ve mesaj iletimi halini almış olduğu tartışılmaktadır. Bu anlamda tüketim kültürünün, kendi kültürünü her yere sirayet ettirmiş olduğu gösterilmektedir. / This paper centres on the notions of consumption, consumption society and consumption culture. It seeks to present a comparative analysis by addressing

  14. Mobilā reklāma kā mobilo priekšapmaksas sarunu karšu reklāmas komunikācijas instruments: Y paaudzes radītās iespējas

    OpenAIRE

    Daudze, Anita

    2009-01-01

    Bakalaura darba temats ir „Mobilā reklāma kā mobilo priekšapmaksas sarunu karšu reklāmas komunikācijas instruments: Y paaudzes radītās iespējas”. Pētījuma problēma ir mobilās reklāmas piemērotība komunikācijai ar Y paaudzes pārstāvjiem – mobilo priekšapmaksas sarunu karšu lietotājiem. Darba teorētiskais pamatojums balstīts uz Y paaudzes jēdziena izpratni, mobilā telefona kā reklāmas komunikācijas kanāla aplūkošanu, kā arī mobilā mārketinga un reklāmas pamatprincipu izklāstu. Darbā izman...

  15. Geleneksel Mağazalar ile İnternetten Alışverişte Değer Algısı ve Satınalma Niyeti: Bir Karşılaştırma

    OpenAIRE

    Kaya, İsmail; Özen, Hilal

    2012-01-01

    ÖzetGünümüzde geleneksel dağıtım kanalları, internetten alışverişin getirdiği bazı tehditlerle karşı karşıya görünmektedirler. Müşterilerin değer algılarının bu iki kanal arasında anlamlı derecede farklılık gösterebilme ihtimali, tüketicilerin alışverişlerini birinden diğerine kaydırma ihtimalini de beraberinde getirmektedir. Temelde, geleneksel mağazalar ve sanal mağazaların tüketicilerinin değer algılamaları itibariyle ele alındığı bu çalışmada, özelde, değer algılamasının satın alma niyeti...

  16. Hayata ve Vücut Dokunulmazlığına Karşı İşlenen Suçlarda Kadın Suçluluğu ve Dindarlık İlişkisi / Female Criminality and Religiosity in the Homicide and Assault Crimes

    Directory of Open Access Journals (Sweden)

    Fatma Kenevir

    2017-06-01

    Full Text Available Abstract        This study consists of the results of the research conducted with convicted female prisoners who committed crimes against the immunity and body immunity in Ankara (Sincan, İzmir (Şakran and İstanbul (Bakırköy women's closed prisons. The scope of the research includes women convicted of crimes against life and body immunity, who are more religious than prisoners convicted of theft, drugs etc. In this respect, the factors that lead to the criminality of women, who were convicted of murder or attempt murder, convicted of wounding offenses and who defined themselves as religious, are determined. Another aim is to demonstrate the crime and victim relationship, how convicts explain criminal actions to themselves and their surroundings and how they justify themselves. Questionnaires and semi-structured interview techniques were used as a method. In this direction, the findings obtained from the results of the questionnaire conducted with 151 women convicts were evaluated by descriptive statistical method and the results of semi-structured interviews with 8 women were included in the results. These types of explanations, included in neutralization techniques, are: commitment to values, the role of the victim, and rejection of responsibility. In the first place, the victim sees the situation as a matter of honor and explains the guilt involved with their beliefs / beliefs. Secondly, the violence (domestic problems that is experienced is said to be the result, as in the opposite party deserves it. In the third place, the victim rejects the responsibility, indicating that the mental illness or depression is the result of suicide. Öz      Bu çalışma, Ankara (Sincan, İzmir (Şakran ve İstanbul (Bakırköy kadın kapalı ceza infaz kurumlarında bulunan hayata ve vücut dokunulmazlığına karşı suç işlemiş hükümlü kadın mahkûmlarla yapılan araştırma sonuçlarından oluşmaktadır. Araştırmanın kapsam

  17. AA2024 Alüminyum Alaşımının Sürtünme Karıştırma Kaynağında Farklı Parametrelerin Mekanik Özelliklere Etkisinin İncelenmesi

    Directory of Open Access Journals (Sweden)

    Aydın ŞIK

    2010-02-01

    Full Text Available Bu çalışmada, genel özelliği hafifliği, işlenebilirliği, yüksek korozyon dayancı, yüksek dayanıma sahip olmasından dolayı kullanım alanı olarak özellikle uçak gövdelerinde ve kanatlarda ve otomotiv endüstrilerinde kullanılan AA2024 alaşımı sürtünme karıştırma kaynağı yöntemi ile birleştirilerek, oluşan bağlantıların yorulma, sertlik, eğme ve çekme deneyleri incelenmiştir. 4 mm kalınlığındaki levhaların kaynak esnasında kaynak ilerleme hızı ve karıştırıcı ucun dönme devri değişken parametreler olarak belirlenmiştir. Bu parametreler; 20 mm omuz genişliği, devir sayısı 1000 dev/dak, 1500 dev/dak, 2500 dev/dak ve ilerleme hızları 120 mm/dak ve 200 mm/ dak olarak alınmıştır.

  18. The interleukin-4 receptor: signal transduction by a hematopoietin receptor.

    Science.gov (United States)

    Keegan, A D; Pierce, J H

    1994-02-01

    Over the last several years, the receptors for numerous cytokines have been molecularly characterized. Analysis of their amino acid sequences shows that some of these receptors bear certain motifs in their extracellular domains that define a family of receptors called the Hematopoietin receptor superfamily. Significant advances in characterizing the structure, function, and mechanisms of signal transduction have been made for several members of this family. The purpose of this review is to discuss the recent advances made for one of the family members, the interleukin (IL) 4 receptor. Other receptor systems have recently been reviewed elsewhere. The IL-4 receptor consists of, at the minimum, the cloned 140 kDa IL-4-binding chain with the potential for associating with other chains. The IL-4 receptor transduces its signal by activating a tyrosine kinase that phosphorylates cellular substrates, including the receptor itself, and the 170 kDa substrate called 4PS. Phosphorylated 4PS interacts with the SH2 domain of the enzyme PI-3'-kinase and increases its enzymatic activity. These early events in the IL-4 receptor initiated signaling pathway may trigger a series of signals that will ultimately lead to an IL-4 specific biologic outcome.

  19. Meeting report: nuclear receptors

    DEFF Research Database (Denmark)

    Tuckermann, Jan; Bourguet, William; Mandrup, Susanne

    2010-01-01

    The biannual European Molecular Biology Organization (EMBO) conference on nuclear receptors was organized by Beatrice Desvergne and Laszlo Nagy and took place in Cavtat near Dubrovnik on the Adriatic coast of Croatia September 25-29, 2009. The meeting brought together researchers from all over...... the world covering a wide spectrum from fundamental mechanistic studies to metabolism, clinical studies, and drug development. In this report, we summarize the recent and exciting findings presented by the speakers at the meeting....

  20. Neurotransmitter receptor imaging

    International Nuclear Information System (INIS)

    Cordes, M.; Hierholzer, J.; Nikolai-Beyer, K.

    1993-01-01

    The importance of neuroreceptor imaging in vivo using single photon emission tomography (SPECT) and positron emission tomography (PET) has increased enormously. The principal neurotransmitters, such as dopamine, GABA/benzodiazepine, acetylcholine, and serotonin, are presented with reference to anatomical, biochemical, and physiological features. The main radioligands for SPECT and PET are introduced, and methodological characteristics of both PET and SPECT presented. Finally, the results of neurotransmitter receptor imaging obtained so far will be discussed. (orig.) [de

  1. Thyroid Stimulating Hormone Receptor

    Directory of Open Access Journals (Sweden)

    Murat Tuncel

    2017-02-01

    Full Text Available Thyroid stimulating hormone receptor (TSHR plays a pivotal role in thyroid hormone metabolism. It is a major controller of thyroid cell function and growth. Mutations in TSHR may lead to several thyroid diseases, most commonly hyperthyroidism. Although its genetic and epigenetic alterations do not directly lead to carcinogenesis, it has a crucial role in tumor growth, which is initiated by several oncogenes. This article will provide a brief review of TSHR and related diseases.

  2. Melatonin Receptor Genes in Vertebrates

    Directory of Open Access Journals (Sweden)

    Hua Dong Yin

    2013-05-01

    Full Text Available Melatonin receptors are members of the G protein-coupled receptor (GPCR family. Three genes for melatonin receptors have been cloned. The MT1 (or Mel1a or MTNR1A and MT2 (or Mel1b or MTNR1B receptor subtypes are present in humans and other mammals, while an additional melatonin receptor subtype, Mel1c (or MTNR1C, has been identified in fish, amphibians and birds. Another melatonin related orphan receptor, GPR50, which does not bind melatonin, is found exclusively in mammals. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. This hormone acts systemically in numerous organs. In the brain, it is involved in the regulation of various neural and endocrine processes, and it readjusts the circadian pacemaker, the suprachiasmatic nucleus. This article reviews recent studies of gene organization, expression, evolution and mutations of melatonin receptor genes of vertebrates. Gene polymorphisms reveal that numerous mutations are associated with diseases and disorders. The phylogenetic analysis of receptor genes indicates that GPR50 is an outgroup to all other melatonin receptor sequences. GPR50 may have separated from a melatonin receptor ancestor before the split between MTNR1C and the MTNR1A/B ancestor.

  3. Flavivirus Entry Receptors: An Update

    Directory of Open Access Journals (Sweden)

    Manuel Perera-Lecoin

    2013-12-01

    Full Text Available Flaviviruses enter host cells by endocytosis initiated when the virus particles interact with cell surface receptors. The current model suggests that flaviviruses use at least two different sets of molecules for infectious entry: attachment factors that concentrate and/or recruit viruses on the cell surface and primary receptor(s that bind to virions and direct them to the endocytic pathway. Here, we present the currently available knowledge regarding the flavivirus receptors described so far with specific attention to C-type lectin receptors and the phosphatidylserine receptors, T-cell immunoglobulin and mucin domain (TIM and TYRO3, AXL and MER (TAM. Their role in flavivirus attachment and entry as well as their implication in the virus biology will be discussed in depth.

  4. Görme Yetersizliğinden Etkilenmiş ve Normal Gelişim Gösteren Çocukların Sosyal Becerilerinin Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Ufuk Özkubat

    2012-01-01

    Full Text Available Bu araştırmanın amacı, 7–12 yaşlarındaki, görme yetersizliğinden etkilenmiş çocukların sosyal beceri düzeylerini normal gelişim gösteren akranları ile karşılaştırmak ve görme yetersizliğinden etkilenmiş çocukların sosyal beceri düzeylerini eğitim ortamı, yaş ve cinsiyet değişkenlerine bağlı olarak değerlendirmektir. Araştırmanın çalışma grubunu, 2009–2010 eğitim-öğretim yılında, Đstanbul Đli’nde yer alan Milli Eğitim Bakanlığı’na bağlı resmi Đlköğretim Okulları’nda bulunan 100 katılımcı oluşturmaktadır. Araştırmanın verileri, Sosyal Beceri Derecelendirme Sistemi (SBDS anasınıfı–6.sınıf öğretmen formu kullanılarak toplanmıştır. Araştırma sonuçları, normal gelişim gösteren çocukların sosyal beceri düzeylerinin, görme yetersizliğinden etkilenmiş çocuklara göre daha gelişmiş olduğunu göstermiştir. Ek olarak, araştırma verileri kaynaştırma ortamlarında bulunan görme yetersizliğinden etkilenmiş çocukların sosyal beceri düzeylerinin ayrıştırılmış eğitim ortamlarında bulunan görme yetersizliğinden etkilenmiş akranlarına göre daha gelişmiş olduğunu göstermiştir. Araştırma bulguları tartışılmış ve uygulamalara yönelik önerilerde bulunulmuştur. The purpose of this study was to compare the social skills of children with visual impairments between the ages of 7 to 12 and typically developing children and to examine children’s social skill differences across their age, gender, and educational settings. The study group consisted of 100 participants attending National Ministry of Education elementary schools located in Istanbul during the academic year of 2009-2010. Study data were gathered using the Social Skills Rating System (SSRS-Teacher report-Turkish form. Findings from the study showed that typically developing children display higher levels of social skills when compared to children with visual impairments

  5. Rb-Sr, K-Ar, and stable isotope evidence for the ages and sources of fluid components of gold-bearing quartz veins in the northern Sierra Nevada foothills metamorphic belt, California

    Science.gov (United States)

    Böhlke, John Karl; Kistler, R. W.

    1986-01-01

    Gold-bearing quartz veins occur in and near major fault zones in deformed oceanic and island-arc rocks west of the main outcrop of the Sierra Nevada composite batholith. Veins typically occupy minor reverse faults that crosscut blueschist to amphibolite-grade metamorphic rocks whose metamorphic ages range from early Paleozoic to Jurassic. Vein micas and carbonate-quartz-mica assemblages that formed by hydrothermal metasomatism of ultramafic wall rocks in the Alleghany, Grass Valley, Washington, and Mother Lode districts yield concordant K-Ar and Rb-Sr ages. The dated veins are significantly younger than prograde metamorphism, penetrative deformation, and accretion of their host rocks to the continental margin. New and previously published mineralization ages from 13 localities in the Sierra foothills range from about 140 to 110 m.y. ago, with mean and median between 120 and 115 m.y. The age relations suggest that mineralizing fluids were set in motion by deep magmatic activity related to the resumption of east-dipping subduction along the western margin of North America following the Late Jurassic Nevadan collision event.CO 2 -bearing fluids responsible for metasomatism and much of the vein mica, carbonate, albite, and quartz deposition in several northern mines were isotopically heavy (delta 18 O [asymp] 8-14ppm; delta D between about -10 and -50ppm) and do not resemble seawater, magmatic, or meteoric waters. Metasomatic and vein-filling mica, dolomite, magnesite, and quartz in altered ultramafic rocks generally formed from fluids with similar Sr and O isotope ratios at a given locality. Consistent quartz-mica delta 18 O fractionations (delta 18 O (sub Q-M) = 4.5-4.9ppm) from various localities imply uniform equilibration temperatures, probably between 300 degrees and 350 degrees C. On a local (mine) scale, fluids responsible for both carbonate alteration of mafic and ultramafic wall rocks and albitic alteration of felsic and pelitic rocks had similar Sr isotope

  6. Otizm Spektrum Bozukluğu Olan ve Normal Gelişim Gösteren Çocuklarda Anne-Çocuk Etkileşiminin Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Yasemin Doğan

    2016-04-01

    Full Text Available Bu araştırmada otizm spektrum bozukluğu (OSB olan çocuğa sahip (n=34 annelerin ve normal gelişim gösteren (NG çocuğa sahip (n=28 annelerin ebeveyn-çocuk etkileşimi sırasında sergiledikleri etkileşimsel davranışları karşılaştırılmıştır. Araştırma kapsamında çalışma grubunda yer alan annelerin serbest oyun bağlamında çocukları ile etkileşimlerinin video kayıtları alınmıştır. Kayıtlar anne davranışları için oluşturulan beş kategori ve annelerin çocuklarına sunduğu pekiştireçlerin analizi ile incelenmiştir. Anne etkileşimsel davranışları kategorileri; yönlendirici olma, başarı odaklı olma, yanıtlayıcı olma, sıcak olma ve etkileşimsizliktir. Araştırma bulguları OSB‟li çocuğu olan annelerin NG‟li çocuğu olan annelere oranla daha fazla yönlendirici vedaha az yanıtlayıcı etkileşimsel davranışlar sergiledikleri yönündedir. Araştırma bulguları erken çocukluk döneminde OSB‟li çocuğu olan ve NG‟li çocuğu olan annelerin çocuklarına yönelik etkileşimsel davranışları bağlamında tartışılmış ve ileride yapılacak araştırmalara yönelik önerilere yer verilmiştir. This study compares the interactional behaviors of mothers of children with autism spectrum disorders (n=34 and mothers of typically developing children (n=28 through mother-child dyads. Participating mothers and their children were recorded while playing in an unstructured environment. Data were analyzed using five distinct mother interactional behavior categories and mother reinforcements used during the interactions. Mother interactional behaviors were: Directiveness, achievement orientation, responsivity, warmth and un-engagement. Study results were discussed in regard to the interactional behaviors of mothers of children with ASD and TD with their children and suggestions for future research were provided .

  7. Adenosine Receptors and Wound Healing

    Directory of Open Access Journals (Sweden)

    Bruce N. Cronstein

    2004-01-01

    Full Text Available Recent studies have demonstrated that application of topical adenosine A2A receptor agonists promotes more rapid wound closure and clinical studies are currently underway to determine the utility of topical A2A adenosine receptor agonists in the therapy of diabetic foot ulcers. The effects of adenosine A2A receptors on the cells and tissues of healing wounds have only recently been explored. We review here the known effects of adenosine A2A receptor occupancy on the cells involved in wound healing.

  8. Virally encoded 7TM receptors

    DEFF Research Database (Denmark)

    Rosenkilde, M M; Waldhoer, M; Lüttichau, H R

    2001-01-01

    expression of this single gene in certain lymphocyte cell lineages leads to the development of lesions which are remarkably similar to Kaposi's sarcoma, a human herpesvirus 8 associated disease. Thus, this and other virally encoded 7TM receptors appear to be attractive future drug targets.......A number of herpes- and poxviruses encode 7TM G-protein coupled receptors most of which clearly are derived from their host chemokine system as well as induce high expression of certain 7TM receptors in the infected cells. The receptors appear to be exploited by the virus for either immune evasion...

  9. Adenosine receptor desensitization and trafficking.

    Science.gov (United States)

    Mundell, Stuart; Kelly, Eamonn

    2011-05-01

    As with the majority of G-protein-coupled receptors, all four of the adenosine receptor subtypes are known to undergo agonist-induced regulation in the form of desensitization and trafficking. These processes can limit the ability of adenosine receptors to couple to intracellular signalling pathways and thus reduce the ability of adenosine receptor agonists as well as endogenous adenosine to produce cellular responses. In addition, since adenosine receptors couple to multiple signalling pathways, these pathways may desensitize differentially, while the desensitization of one pathway could even trigger signalling via another. Thus, the overall picture of adenosine receptor regulation can be complex. For all adenosine receptor subtypes, there is evidence to implicate arrestins in agonist-induced desensitization and trafficking, but there is also evidence for other possible forms of regulation, including second messenger-dependent kinase regulation, heterologous effects involving G proteins, and the involvement of non-clathrin trafficking pathways such as caveolae. In this review, the evidence implicating these mechanisms is summarized for each adenosine receptor subtype, and we also discuss those issues of adenosine receptor regulation that remain to be resolved as well as likely directions for future research in this field. Copyright © 2010 Elsevier B.V. All rights reserved.

  10. Üniversite Öğrencilerinin ‘‘Topluluk Karşısında Konuşma’’ İle İlgili Çeşitli Görüşleri Some Opinions of the University Students Related to “Giving a Speech in Front of Public”

    Directory of Open Access Journals (Sweden)

    Akif ARSLAN

    2012-09-01

    Full Text Available This study aims to determine various opinions of university students related to the skill of making a speech in front of the public.With this aim 500 university students, attending different departments at Ağrı İbrahim Çecen University, were administered a questionnaire developed by the researcher, and the data of research are gathered. As a result of this study, it is determined that many of the students want to give a speech in front of the public but because of various reasons such as not to have adequacy in Turkish, acquiring Turkish as a second language, the fear of giving wrong or inadequate knowledge, audience’s sarcastic reactions, lack of self-confidence, shy personality, accent problems, worry of not being understood etc. even if they have the chance, they do not speak in front of the public or they avoid the duties required giving speech in front of the public. It is also identified that the students in this study are of the idea that this skill is not improved at educational institutions because of some reasons such as only successful students’ being given the right of the speech, the activities in front of the public’s being limited to some official ceremonies, crowded classroom, students not being given right to speak as required and teachers speaking mostly, fear of students from teacher’s reaction and ignoring speaking skills because of focusing on centrally given examinations. In this study, after the students’ psychological and physical characteristics, getting nervous, sweating, fear of being criticized, forgetting what to say, fear of getting dizzy, and blushing, sweating, trembling, headache, stumbling, trilling, heart beat speeding up, swallowing words respectively are determined it is also mentioned what should be done in order to decrease the level of excitement that occurs in front of public. Çalışmanın amacı üniversite öğrencilerinin topluluk karşısında konuşma becerisi ile ilgili çeşitli g

  11. Axonal GABAA receptors.

    Science.gov (United States)

    Trigo, Federico F; Marty, Alain; Stell, Brandon M

    2008-09-01

    Type A GABA receptors (GABA(A)Rs) are well established as the main inhibitory receptors in the mature mammalian forebrain. In recent years, evidence has accumulated showing that GABA(A)Rs are prevalent not only in the somatodendritic compartment of CNS neurons, but also in their axonal compartment. Evidence for axonal GABA(A)Rs includes new immunohistochemical and immunogold data: direct recording from single axonal terminals; and effects of local applications of GABA(A)R modulators on action potential generation, on axonal calcium signalling, and on neurotransmitter release. Strikingly, whereas presynaptic GABA(A)Rs have long been considered inhibitory, the new studies in the mammalian brain mostly indicate an excitatory action. Depending on the neuron that is under study, axonal GABA(A)Rs can be activated by ambient GABA, by GABA spillover, or by an autocrine action, to increase either action potential firing and/or transmitter release. In certain neurons, the excitatory effects of axonal GABA(A)Rs persist into adulthood. Altogether, axonal GABA(A)Rs appear as potent neuronal modulators of the mammalian CNS.

  12. Orman Kanunu’nun 16’ncı maddesi uygulamalarında alınan bedellerin hesaplanma yaklaşımının değer belirleme yöntemleriyle karşılaştırmalı irdelenmesi

    Directory of Open Access Journals (Sweden)

    Prof.Dr. Kenan Ok

    2017-07-01

    Full Text Available Orman alanlarında sıklıkla maden çıkarılmak istenmektedir. Bu istek, madencilik üretimini artırırken ormancılık üretimlerini azaltmaktadır. Refah ekonomisinin klasik sorunu olan, sektörler arası tahsis kararları, ülkemiz ormancılık uygulamaları içerisinde, arazi izin ve ağaçlandırma bedellerinin belirlenmesi sorunu şeklinde görülmektedir. Bu çalışmanın amacı, Orman Genel Müdürlüğünün (OGM Orman Kanunu’nun 16’ncı maddesi gereği verdiği izinlerde talep ettiği bedelleri hesaplama yaklaşımı ile evrensel değer belirleme yöntemlerini karşılaştırmalı olarak irdelemektir. Bu amaçla, seçilen gerçek bir olayın verileri örnek alınarak OGM’nin ilgili yönetmeliğinin kabul ettiği değer hesapları yapılmıştır. Bu hesaplama yaklaşımı ile evrensel değer belirleme yaklaşımları karşılaştırılmış ve yönetmelikle ortaya konan yaklaşımın kısmen maliyetlere dayalı bir bakış içerdiği, pazar fiyatları, toplumsal tercihler ve transfer edilen faydalarla ilgilenmediği görülmüştür. Buna ek olarak, yönetmelikle ortaya konan yaklaşımın temel bileşenlerinin, bilimsel bulgular yerine idari kararlara dayalı olarak kurgulandığı saptanmıştır.

  13. Possible Relevance of Receptor-Receptor Interactions between Viral- and Host-Coded Receptors for Viral-Induced Disease

    Directory of Open Access Journals (Sweden)

    Luigi F. Agnati

    2007-01-01

    Full Text Available It has been demonstrated that some viruses, such as the cytomegalovirus, code for G-protein coupled receptors not only to elude the immune system, but also to redirect cellular signaling in the receptor networks of the host cells. In view of the existence of receptor-receptor interactions, the hypothesis is introduced that these viral-coded receptors not only operate as constitutively active monomers, but also can affect other receptor function by interacting with receptors of the host cell. Furthermore, it is suggested that viruses could also insert not single receptors (monomers, but clusters of receptors (receptor mosaics, altering the cell metabolism in a profound way. The prevention of viral receptor-induced changes in host receptor networks may give rise to novel antiviral drugs that counteract viral-induced disease.

  14. Receptor studies in biological psychiatry

    International Nuclear Information System (INIS)

    Fujiwara, Yutaka

    1992-01-01

    Recent advances in the pharmacological treatment of endogenous psychosis have led to the development of biological studies in psychiatry. Studies on neurotransmitter receptors were reviewed in order to apply positron-emission tomograph (PET) for biological psychiatry. The dopamine (DA) hypothesis for schizophrenia was advanced on the basis of the observed effects of neuroleptics and methamphetamine, and DA(D 2 ) receptor supersensitivity measured by PET and receptor binding in the schizophrenic brain. The clinical potencies of neuroleptics for schizophrenia were correlated with their abilities to inhibit the D 2 receptor, and not other receptors. The σ receptor was expected to be a site of antipsychotic action. However, the potency of drugs action on it was not correlated with clinical efficacy. Haloperidol binds with high affinity to the σ receptor, which may mediate acute dystonia, an extrapyramidal side effect of neuroleptics. Behavioral and neurochemical changes induced by methamphetamine treatment were studied as an animal model of schizophrenia, and both a decrease of D 2 receptor density and an increase of DA release were detected. The monoamine hypothesis for manic-depressive psychosis was advanced on the basis of the effect of reserpine, monoamine oxidase inhibitor and antidepressants. 3 H-clonidine binding sites were increased in platelet membranes of depressive patients, 3 H-imipramine binding sites were decreased. The GABA A receptor is the target site for the action of anxiolytics and antiepileptics such as benzodiazepines and barbiturates. Recent developments in molecular biology techniques have revealed the structure of receptor proteins, which are classified into two receptor families, the G-protein coupled type (D 2 ) and the ion-channel type (GABA A ). (J.P.N.)

  15. Quantitative analysis of receptor imaging

    International Nuclear Information System (INIS)

    Fu Zhanli; Wang Rongfu

    2004-01-01

    Model-based methods for quantitative analysis of receptor imaging, including kinetic, graphical and equilibrium methods, are introduced in detail. Some technical problem facing quantitative analysis of receptor imaging, such as the correction for in vivo metabolism of the tracer and the radioactivity contribution from blood volume within ROI, and the estimation of the nondisplaceable ligand concentration, is also reviewed briefly

  16. Coronavirus spike-receptor interactions

    NARCIS (Netherlands)

    Mou, H.

    2015-01-01

    Coronaviruses cause important diseases in humans and animals. Coronavirus infection starts with the virus binding with its spike proteins to molecules present on the surface of host cells that act as receptors. This spike-receptor interaction is highly specific and determines the virus’ cell, tissue

  17. Neurobeachin regulates neurotransmitter receptor trafficking to synapses

    NARCIS (Netherlands)

    Nair, R.; Lauks, J.; Jung, S; Cooke, N.E.; de Wit, H.; Brose, N.; Kilimann, M.W.; Verhage, M.; Rhee, J.

    2013-01-01

    The surface density of neurotransmitter receptors at synapses is a key determinant of synaptic efficacy. Synaptic receptor accumulation is regulated by the transport, postsynaptic anchoring, and turnover of receptors, involving multiple trafficking, sorting, motor, and scaffold proteins. We found

  18. A Novel Mechanism of Androgen Receptor Action

    National Research Council Canada - National Science Library

    Roberts, Jr, Charles T

    2006-01-01

    .... Specifically, the authors had determined that the androgen receptor controls the expression of the cell-surface receptor for the hormone IGF-1 at the level of translation of the IGF-1 receptor mRNA...

  19. Quantitative densitometry of neurotransmitter receptors

    International Nuclear Information System (INIS)

    Rainbow, T.C.; Bleisch, W.V.; Biegon, A.; McEwen, B.S.

    1982-01-01

    An autoradiographic procedure is described that allows the quantitative measurement of neurotransmitter receptors by optical density readings. Frozen brain sections are labeled in vitro with [ 3 H]ligands under conditions that maximize specific binding to neurotransmitter receptors. The labeled sections are then placed against the 3 H-sensitive LKB Ultrofilm to produce the autoradiograms. These autoradiograms resemble those produced by [ 14 C]deoxyglucose autoradiography and are suitable for quantitative analysis with a densitometer. Muscarinic cholinergic receptors in rat and zebra finch brain and 5-HT receptors in rat brain were visualized by this method. When the proper combination of ligand concentration and exposure time are used, the method provides quantitative information about the amount and affinity of neurotransmitter receptors in brain sections. This was established by comparisons of densitometric readings with parallel measurements made by scintillation counting of sections. (Auth.)

  20. Dopamine Receptors and Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Shin Hisahara

    2011-01-01

    Full Text Available Parkinson's disease (PD is a progressive extrapyramidal motor disorder. Pathologically, this disease is characterized by the selective dopaminergic (DAergic neuronal degeneration in the substantia nigra. Correcting the DA deficiency in PD with levodopa (L-dopa significantly attenuates the motor symptoms; however, its effectiveness often declines, and L-dopa-related adverse effects emerge after long-term treatment. Nowadays, DA receptor agonists are useful medication even regarded as first choice to delay the starting of L-dopa therapy. In advanced stage of PD, they are also used as adjunct therapy together with L-dopa. DA receptor agonists act by stimulation of presynaptic and postsynaptic DA receptors. Despite the usefulness, they could be causative drugs for valvulopathy and nonmotor complication such as DA dysregulation syndrome (DDS. In this paper, physiological characteristics of DA receptor familyare discussed. We also discuss the validity, benefits, and specific adverse effects of pharmaceutical DA receptor agonist.

  1. Molecular characterization of opioid receptors

    Energy Technology Data Exchange (ETDEWEB)

    Howard, A.D.

    1986-01-01

    The aim of this research was to purify and characterize active opioid receptors and elucidate molecular aspects of opioid receptor heterogeneity. Purification to apparent homogeneity of an opioid binding protein from bovine caudate was achieved by solubilization in the non-ionic detergent, digitonin, followed by sequential chromatography on the opiate affinity matrix, ..beta..-naltrexylethylenediamine-CH-Sepharose 4B, and on the lectine affinity matrix, wheat germ agglutinin-agarose. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) followed by autoradiography revealed that radioiodinated purified receptor gave a single band. Purified receptor preparations showed a specific activity of 12,000-15,000 fmol of opiate bound per mg of protein. Radioiodinated human beta-endorphin (/sup 125/I-beta-end/sub H/) was used as a probe to investigate the ligand binding subunits of mu and delta opioid receptors. /sup 125/I-beta-end/sub H/ was shown to bind to a variety of opioid receptor-containing tissues with high affinity and specificity with preference for mu and delta sites, and with little, if any, binding to kappa sites. Affinity crosslinking techniques were employed to covalently link /sup 125/I-beta-end/sub H/ to opioid receptors, utilizing derivatives of bis-succinimidyl esters that are bifunctional crosslinkers with specificities for amino and sulfhydryl groups. This, and competition experiments with high type-selective ligands, permitted the assignment of two labeled peptides to their receptor types, namely a peptide of M/sub r/ = 65,000 for mu receptors and one of M/sub r/ = 53,000 for delta receptors.

  2. Larinks kanserli hastalarda serum CA 72-4, CA 19-9, CEA ve kombine tümör marker seviyelerinin karşılaştırılması ve prognostik değerleri

    OpenAIRE

    Altaş, Enver; Kızıltunç, Ahmet; Karaşen, R.Murat; Öztürk, Aziz; Sütbeyaz, Yavuz; Gündoğdu, Cemal

    2009-01-01

    SüleymanDemirel Üniversitesi TIP FAKÜLTESİ DERGİSİ: 1997 Haziran; 4(3) Larinks kanserli hastalarda serum CA 72-4, CA 19-9, CEA ve kombine tümör marker seviyelerinin karşılaştırılması ve prognostik değerleri Enver Altaş Ahmet Kızıltunç R. Murat Karaşen Aziz Öztürk Yavuz Sütbeyaz Cemal Gündoğdu ÖzetLarinks kanserli hastaların tedavi etkinliklerinin takibinde çeşitli klinik ve laboratuvar tetkikleri kullanılmaktadır. Tümör markerleri de bu tetkiklerden birisidir. Ancak, CA 19-9 (Carbohydr...

  3. Seçici Özellikteki Farklı Besiyerlerinin bazı Mayaların Meyveli Yoğurttan Geri Kazanımları Amacı ile Karşılaştırılmaları (İngilizce)

    OpenAIRE

    Şule Şenses Ergül; Z. Yeşim Özbaş

    2015-01-01

    Bu çalışmada, yapay olarak aşılanan meyveli yoğurt örneklerinden bazı mayaların izolasyonu için kullanılabilecek farklı besiyerleri karşılaştırılmıştır. Bu amaçla, kontrol besiyeri olarak malt extract agar ve beş farklı seçici besiyeri kullanılmıştır. Bu besiyerleri; malt extract yeast extract %50 fructose glucose agar, malt extract yeast extract %40 sucrose agar, malt extract yeast extract glucose %0.8 peptone agar, malt extract yeast extract glucose %0.1 peptone agar and potato dextrose %50...

  4. “Cihanda Türk” Ve “Şarkımız” Şiirlerinin Varlıkbilim Açısından / Ontolojik Açıdan Karşılaştırılması Ontological Comparison Of “Cihanda Türk” And “Şarkimiz” Poems

    Directory of Open Access Journals (Sweden)

    Salim DURUKOĞLU

    2013-09-01

    orplagiarism, parallel these concepts are closer. Gustave Lanson’a göre, en özgün yazarların bile kişiliği geçmiş nesillerin ve edebi akımların sentezi olarak dörtte üç oranında ödünçleme ögelerden oluştuğu için her şairin yahut yazarın ufkunda başka şair ve yazarlar ile kendinden önce yazılmış edebi metinler vardır. Mitolojik bağlamda, bir söz söylediğinde bunun kendinden önce söylenmediğini bilme olanağına sahip tek kişi Hz. Adem yahut eşi Hz. Havva’dır. Uygarlık, insanlığın ulaştığı en büyük fikir sentezi olarak tanımlanır. Kendisinden zengin kültür ve uygarlıklarla karşılaşmayan ve bunlardan yararlanmayan kültürlerin gelişmesi ve uygarlık düzeyine yükselmesi nasıl mümkün değilse; bir yazarın öteki yazarlar ile karşı karşıya gelmemesi, onları keşfedip kendine mal etmemesi de mümkün değildir. Bu ilişkiler ağı içinden, yazarlık (metnimiz bağlamında şairlik da bir yazarın ulaştığı en büyük fikir sentezidir, çıkarımına ve tanımına ulaşabiliriz.Yazarların birbirlerinden etkilenmeleri doğal olduğu kadar üzerinde durulmaya değecek kertede ilginçtir ve karşılaştırmalı edebiyatın en önemli çalışma alanıdır. Bu yazıda Bekir Sıtkı Erdoğan’ın Cihanda Türk adlı şiiri ile Necip Fazıl Kısakürek’in Şarkımız adlı şiirleri ontolojik açıdan karşılaştırılmıştır. Makalemizde karşılaştırmalı edebiyatın kısa tarihi verildikten ve ontolojik yönteme göre edebi eserdeki varlık tabakaları özetlendikten sonra geçilen karşılaştırmada önce şiirlerin yayın serüveni üzerinde durularak, sahih bir metne ulaşılmaya çalışılmış; devamında edebi eserde varlık tabakaları olarak iç içe geçmiş olan ses tabakaları, anlam tabakaları, farklı şematik görüşler tabakları, alınyazısı tabakaları ayrıştırılmaya çalışılarak değerlendirmeler yapılmıştır. Sonuç başlığında ise aklama yahut karalama amacı g

  5. U/Pb (SHRIMP), {sup 207}Pb/{sup 206}Pb, Rb/Sr, Sm/Nd e K/Ar geochronology of granite-greenstone terrains of Gaviao Block: implications for the Proterozoic and Archean evolution of Sao Francisco Craton, Brazil; Geocronologia U/Pb (SHRIMP), {sup 207}Pb/{sup 206}Pb, Rb/Sr, Sm/Nd e K/Ar dos terrenos granito-greenstone do Bloco do Gaviao: implicacoes para a evolucao arqueana e proterozoica do craton do Sao Francisco, Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Leal, Luiz Rogerio Bastos

    1998-07-01

    The Gaviao Block (GB) in the northern portion of the Sao Francisco Craton-Northeast of Brazil, constitutes one of the oldest Archean fragments of the South American Platform Archean crust. GB underwent several events of juvenile accretion and reworking of continental crust along its evolutionary history, notably between the Archean and the Paleoproterozoic. {sup 207}Pb/{sup 206}Pb isotopic analyses were carried out in two zircons populations from strongly migmatized TTG terranes found in the proximity of Brumado: the first population (7 crystals) is taken as representative of the crystallization period of the TTG terranes at 3300 {+-} 45 Ma; the second (2 crystals) represents the age of the first even of metamorphism/migmatization at 2910 {+-} 10 Ma. {sup 207} Pb/{sup 206} Pb analyses in zircons from an outcrop of non-migmatized TTG in the area yielded a 3202 {+-} 15 Ma age (4 crystals), interpreted to be the crystallization period of the gneiss protolith. Sm/Nd analyses on the TTG rocks of the Brumado region yielded T{sub DM} model ages varying between 3.26 and 3.36 Ga and {epsilon}{sub Nd}{sup (t)} between -3.5 and +0.7. These data suggest the occurrence of juvenile accretions to the continental crust during the Archean, with differential involvement of crustal materials. The geochemical data of rare earth elements corresponding to the TTG terranes revealed moderate LRRE contents (La{sub N}=83,5), low HREE contents (La{sub N}=2,5) and a fairly fractionated pattern (La/Yb){sub N}=34, besides lack of negative Eu anomaly, showing that these rocks have similar compositions to those TTG terranes of cratonic continents, as well as some Archean rocks from CSF (e.g. Sete Voltas, Boa Vista). Finally, the youngest ages present in GB rocks (ca. 1.2-0.45 Ga) represent the role played by tectono thermal events, which produced partial or total rejuvenation of the Rb/Sr and K/Ar isotopic systems during the Espinhaco and Brasiliano cycles. In particular, K/Ar ages illustrate the

  6. Stargazin Modulation of AMPA Receptors

    Directory of Open Access Journals (Sweden)

    Sana A. Shaikh

    2016-10-01

    Full Text Available Fast excitatory synaptic signaling in the mammalian brain is mediated by AMPA-type ionotropic glutamate receptors. In neurons, AMPA receptors co-assemble with auxiliary proteins, such as stargazin, which can markedly alter receptor trafficking and gating. Here, we used luminescence resonance energy transfer measurements to map distances between the full-length, functional AMPA receptor and stargazin expressed in HEK293 cells and to determine the ensemble structural changes in the receptor due to stargazin. In addition, we used single-molecule fluorescence resonance energy transfer to study the structural and conformational distribution of the receptor and how this distribution is affected by stargazin. Our nanopositioning data place stargazin below the AMPA receptor ligand-binding domain, where it is well poised to act as a scaffold to facilitate the long-range conformational selection observations seen in single-molecule experiments. These data support a model of stargazin acting to stabilize or select conformational states that favor activation.

  7. Radioiodinated ligands for dopamine receptors

    International Nuclear Information System (INIS)

    Kung, H.F.

    1994-01-01

    The dopamine receptor system is important for normal brain function; it is also the apparent action site for various neuroleptic drugs for the treatment of schizophrenia and other metal disorders. In the past few years radioiodinated ligands for single photon emission tomography (SPECT) have been successfully developed and tested in humans: [ 123 I]TISCH for D1 dopamine receptors; [ 123 I]IBZM, epidepride, IBF and FIDA2, four iodobenzamide derivatives, for D2/D3 dopamine receptors. In addition, [ 123 I]β-CIT (RTI-55) and IPT, cocaine derivatives, for the dopamine reuptake site are potentially useful for diagnosis of loss of dopamine neurons. The first iodinated ligand, (R)trans-7-OH-PIPAT, for D3 dopamine receptors, was synthesized and characterized with cloned cell lines (Spodoptera frugiperda, Sf9) expressing the D2 and D3 dopamine receptors and with rat basal forebrain membrane preparations. Most of the known iodobenzamides displayed similar potency in binding to both D2 and D3 dopamine receptors expressed in the cell lines. Initial studies appear to suggest that by fine tuning the structures it may be possible to develop agents specific for D2 and D3 dopamine receptors. It is important to investigate D2/D3 selectivity for this series of potent ligands

  8. Labeled receptor ligands for spect

    International Nuclear Information System (INIS)

    Kung, H.F.

    1989-01-01

    Receptor specific imaging agents for single photon emission computed tomography (SPECT) can potentially be useful in the understanding of basic biochemistry and pharmacology of receptors. SPECT images may also provide tools for evaluation of density and binding kinetics of a specific receptor, information important for diagnosis and patient management. Basic requirements for receptor imaging agents are: (a) they are labeled with short-lived isotopes, (b) they show high selectivity and specific uptake, (c) they exhibit high target/background ratio, and (d) they can be modeled to obtain quantitative information. Several good examples of CNS receptor specific ligands labeled with I-123 have been developed, including iodoQNB, iodoestrogen iodobenzadiazepine, iodobenazepine, iodobenzamides for muscarinic, estrogen benzadiazepine, D-1 and D-2 dopamine receptors. With the advent of newer and faster SPECT imaging devices, it may be feasible to quantitate the receptor density by in vivo imaging techniques. These new brain imaging agents can provide unique diagnostic information, which may not be available through other imaging modalities, such as CT and MRI

  9. High-resolution immunogold localization of AMPA type glutamate receptor subunits at synaptic and non-synaptic sites in rat hippocampus.

    Science.gov (United States)

    Baude, A; Nusser, Z; Molnár, E; McIlhinney, R A; Somogyi, P

    1995-12-01

    The cellular and subcellular localization of the GluRA, GluRB/C and GluRD subunits of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) type glutamate receptor was determined in the rat hippocampus using polyclonal antipeptide antibodies in immunoperoxidase and immunogold procedures. For the localization of the GluRD subunit a new polyclonal antiserum was developed using the C-terminal sequence of the protein (residues 869-881), conjugated to carrier protein and absorbed to colloidal gold for immunization. The purified antibodies immunoprecipitated about 25% of 3[H]AMPA binding activity from the hippocampus, cerebellum or whole brain, but very little from neocortex. These antibodies did not precipitate a significant amount of 3[H]kainate binding activity. The antibodies also recognize the GluRD subunit, but not the other AMPA receptor subunits, when expressed in transfected COS-7 cells and only when permeabilized with detergent, indicating an intracellular epitope. All subunits were enriched in the neuropil of the dendritic layers of the hippocampus and in the molecular layer of the dentate gyrus. The cellular distribution of the GluRD subunit was studied more extensively. The strata radiatum, oriens and the dentate molecular layer were more strongly immunoreactive than the stratum lacunosum moleculare, the stratum lucidum and the hilus. However, in the stratum lucidum of the CA3 area and in the hilus the weakly reacting dendrites were surrounded by immunopositive rosettes, shown in subsequent electron microscopic studies to correspond to complex dendritic spines. In the stratum radiatum, the weakly reacting apical dendrites contrasted with the surrounding intensely stained neuropil. The cell bodies of pyramidal and granule cells were moderately reactive. Some non-principal cells and their dendrites in the pyramidal cell layer and in the alveus also reacted very strongly for the GluRD subunit. At the subcellular level, silver intensified immunogold

  10. Balzac-Tanpınar: İki Hayalî Mülâkatın Karşılaştırılması Balzac-Tanpinar: Comparing Two Imaginary Interview

    Directory of Open Access Journals (Sweden)

    Abdurrahman KOLCU

    2013-03-01

    olarak sunulur, onun görüş ve tutumları ön plana çıkarılır.20. yüzyıl Türk edebiyatının en önemli kişiliklerinden biri olan Ahmet Hamdi Tanpınar benzer bir hayalî mülakatı, yaklaşık yüzyıl sonra, Halit Ziya Uşaklıgil’in Mai ve Siyah adlı romanının başkahramanı olan Ahmet Cemil ile gerçekleştirir. “Ahmet Cemille Mülakat” başlığını taşıyan bu hayalî mülakat, 1933 yılının son ayında Anayurt dergisinin 8. ve 9. sayılarında yayımlanmıştır. Tanpınar, hayalî mülakatında artık yaşlılık döneminde olan Ahmet Cemil aracılığıyla Servet-i Fünun edebiyatının şiir ve kurgu dünyasını ve o dönemin yaşam biçimini alaycı bir yaklaşımla değerlendirir. Benzer şekilde mülakatın yapıldığı dönemin değişen edebiyat anlayışı ve yaşam biçimiyle ilgili değerlendirmeler de mülakata serpiştirilmiştir.Tanpınar’ın hayalî mülakatında ayrıca Brummell’in hayatı ve dandizm bağlamında değerlendirilebilecek bazı ayrıntılar iki mülakat arasındaki ortak yönleri çoğaltmakta ve bu bağlamda çok daha önce kaleme alınması dolayısıyla Balzac’ın etkisini gündeme getirmektedir.

  11. Albino Farelerde Bisfenol A Tarafından Teşvik Edilen Genotoksisiteye Karşı Yeşil Kahvenin Koruyucu Rolünün Araştırılması

    Directory of Open Access Journals (Sweden)

    Burhan İŞTAR

    2016-09-01

    Full Text Available Özet. Bu çalışmada gıda ve içecek ambalajlama materyallerinde sıkça kullanılan kimyasal maddelerden biri olan Bisfenol A (BFA’nın Swiss albino farelerde muhtemel fizyolojik ve genotoksik etkileri ile bu etkilere karşı yeşil kahvenin koruyucu rolü araştırılmıştır. Fizyolojik etkiler; canlı ağırlık ve karaciğer-böbrek organ ağırlıklarının ölçümü ile genotoksik etkiler ise; eritrosit ve yanak mukoza epitelyum hücrelerindeki mikronukleus (MN sıklığının, kemik iliği hücrelerinde ise kromozomal hasar oluşumunun tespitiyle değerlendirilmiştir. Fareler her grupta altı (6 hayvan olacak şekilde toplam altı (6 gruba ayrılmış, kontrol grubundaki fareler çeşme suyu, uygulama grubundaki fareler ise yeşil kahvenin 100 mg/kg c.a ve 400 mg/kg c.a dozlarıyla ve BFA’nın 50 mg/kg c.a dozuyla beslenmişlerdir. Sonuçta BFA uygulaması canlı ağırlıklarda ve organ ağırlıklarında istatistiksel açıdan önemli bir azalmaya neden olurken, MN ve kromozomal anormallik sıklığında ise önemli bir artışa neden olmuştur. Yeşil kahve uygulaması ise BFA’nın söz konusu olumsuz etkilerini iyileştirerek, tüm parametrelerde doza bağlı bir iyileşme göstermiştir. BFA’nın belli bir doz eşiğinden sonra toksisiteye sebep olduğu, yeşil kahvenin ise bu toksisiteyi azaltmada etkili bir antioksidant ürün olduğu anlaşılmıştır.Anahtar Kelimeler: Bisfenol A, Fizyoloji, Genotoksisite, Kromozomal Anormallikler, Mikronukleus, Yeşil Kahve Abstract. This study researches into the potential physiologic and genotoxic effects of Bisphenol A, which is one of the most frequent chemical substance used in food and beverage packaging materials, on Swiss Albino mice and the protective role of green coffee against these effects. The study analyzes the physiologic effects by measuring the live weight, liver and kidney weight, whilst determining the genotoxic effects by frequency of micronucles (MN on

  12. XMRV: usage of receptors and potential co-receptors

    Directory of Open Access Journals (Sweden)

    Gaddam Durga

    2011-09-01

    Full Text Available Abstract Background XMRV is a gammaretrovirus first identified in prostate tissues of Prostate Cancer (PC patients and later in the blood cells of patients with Chronic Fatigue Syndrome (CFS. Although XMRV is thought to use XPR1 for cell entry, it infects A549 cells that do not express XPR1, suggesting usage of other receptors or co-receptors. Methods To study the usage of different receptors and co- receptors that could play a role in XMRV infection of lymphoid cells and GHOST (GFP- Human osteosarcoma cells expressing CD4 along with different chemokine receptors including CCR1, CCR2, etc., were infected with XMRV. Culture supernatants and cells were tested for XMRV replication using real time quantitative PCR. Results Infection and replication of XMRV was seen in a variety of GHOST cells, LNCaP, DU145, A549 and Caski cell lines. The levels of XMRV replication varied in different cell lines showing differential replication in different cell lines. However, replication in A549 which lacks XPR1 expression was relatively higher than DU145 but lower than, LNCaP. XMRV replication varied in GHOST cell lines expressing CD4 and each of the co- receptors CCR1-CCR8 and bob. There was significant replication of XMRV in CCR3 and Bonzo although it is much lower when compared to DU145, A549 and LNCaP. Conclusion XMRV replication was observed in GHOST cells that express CD4 and each of the chemokine receptors ranging from CCR1- CCR8 and BOB suggesting that infectivity in hematopoietic cells could be mediated by use of these receptors.

  13. Arctigenin reduces neuronal responses in the somatosensory cortex via the inhibition of non-NMDA glutamate receptors

    OpenAIRE

    Borbély, S; Jocsak, Gergely; Moldovan, Kinga; Sedlak, Lucie; Preininger, Eva; Boldizsar, Imre; Toth, Attila; Atlason, Palmi T; Molnar, Elek; Vilagi, Ildiko

    2016-01-01

    Lignans are biologically active phenolic compounds related to lignin, produced in different plants. Arctigenin, a dibenzylbutyrolactone-type lignan, has been used as a neuroprotective agent for the treatment of encephalitis. Previous studies of cultured rat cerebral cortical neurones raised the possibility that arctigenin inhibits kainate-induced excitotoxicity. The aims of the present study were: 1) to analyse the effect of arctigenin on normal synaptic activity in ex vivo brain slices, 2) t...

  14. Quantitative receptor radioautography in the study of receptor-receptor interactions in the nucleus tractus solitarii

    Directory of Open Access Journals (Sweden)

    Fior-Chadi D.R.

    1998-01-01

    Full Text Available The nucleus tractus solitarii (NTS in the dorsomedial medulla comprises a wide range of neuropeptides and biogenic amines. Several of them are related to mechanisms of central blood pressure control. Angiotensin II (Ang II, neuropeptide Y (NPY and noradrenaline (NA are found in the NTS cells, as well as their receptors. Based on this observation we have evaluated the modulatory effect of these peptide receptors on a2-adrenoceptors in the NTS. Using quantitative receptor radioautography, we observed that NPY and Ang II receptors decreased the affinity of a2-adrenoceptors for their agonists in the NTS of the rat. Cardiovascular experiments agreed with the in vitro data. Coinjection of a threshold dose of Ang II or of the NPY agonists together with an ED50 dose of adrenergic agonists such as NA, adrenaline and clonidine counteracted the depressor effect produced by the a2-agonist in the NTS. The results provide evidence for the existence of an antagonistic interaction between Ang II at1 receptors and NPY receptor subtypes with the a2-adrenoceptors in the NTS. This receptor interaction may reduce the transduction over the a2-adrenoceptors which can be important in central cardiovascular regulation and in the development of hypertension

  15. Peripheral adrenergic receptors in hypertension

    NARCIS (Netherlands)

    Michel, M. C.; Brodde, O. E.; Insel, P. A.

    1990-01-01

    Increased sympathoadrenal activity appears to play an important role in the development or maintenance of elevated blood pressure in hypertensive patients and various animal models of hypertension. Alterations of adrenergic receptor number or responsiveness might contribute to this increased

  16. Are olfactory receptors really olfactive?

    DEFF Research Database (Denmark)

    Giorgi, Franco; Maggio, Roberto; Bruni, Luis Emilio

    2011-01-01

    environmental conditions. By adopting this standpoint, the functional attribution as olfactory or chemotactic sensors to these receptors should not be seen neither as a cause conditioning receptor gene expression, nor as a final effect resulting from genetically predetermined programs, but as a direct...... and odor-decoding processes. However, this type of explanation does not entirely justify the role olfactory receptors have played during evolution, since they are also expressed ectopically in different organs and/or tissues. Homologous olfactory genes have in fact been found in such diverse cells and....../or organs as spermatozoa, testis and kidney where they are assumed to act as chemotactic sensors or renin modulators. To justify their functional diversity, homologous olfactory receptors are assumed to share the same basic role: that of conferring a self-identity to cells or tissues under varying...

  17. Nuclear Receptor Signaling Atlas (NURSA)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Nuclear Receptor Signaling Atlas (NURSA) is designed to foster the development of a comprehensive understanding of the structure, function, and role in disease...

  18. L-glutamate Receptor In Paramecium

    Science.gov (United States)

    Bernal-Martínez, Juan; Ortega-Soto, Arturo

    2004-09-01

    Behavioral, electrophysiological and biochemical experiments were performed in order to establish the presence of a glutamate receptor in the ciliate Paramecium. It was found that an AMPA/KA receptor is functionally expressed in Paramecium and that this receptor is immunologically and fillogenetically related to the AMPA/KA receptor present in vertebrates.

  19. Receptor-targeted metalloradiopharmaceuticals. Final technical report

    International Nuclear Information System (INIS)

    Green, Mark A.

    2000-01-01

    Copper (II) and platinum (II) coordination complexes were prepared and characterized. These complexes were designed to afford structural homology with steroidal and non-steroidal estrogens for possible use as receptor-targeted radiopharmaceuticals. While weak affinity for the estrogen receptor was detectable, none would appear to have sufficient receptor-affinity for estrogen-receptor-targeted imaging or therapy

  20. [The receptor theory of atherosclerosis].

    Science.gov (United States)

    Likhoded, V G; Bondarenko, V M; Gintsburg, A L

    2010-01-01

    Lipopolysaccharides of Gram-negative bacteria can interact with Toll-like receptor 4 (TLR4) and induce atheroma formation. The risk of atherosclerosis is decreased in case of TLR4 mutation. Other bacterial ligands and endogenous ligands of TLRs can also be involved in induction of atherogenesis. The general concept of atherosclerosis pathogentsis is presented. According to this concept atherogenesis can be initiated by some reactions resulting from interaction of exogenous and endogenous microbial ligands with Toll-like receptors.

  1. Xenobiotics and the Glucocorticoid Receptor

    International Nuclear Information System (INIS)

    Gulliver, Linda S M

    2017-01-01

    Glucocorticoid Receptor (GR) is present in virtually every human cell type. Representing a nuclear receptor superfamily, GR has several different isoforms essentially acting as ligand-dependent transcription factors, regulating glucocorticoid-responsive gene expression in both a positive and a negative manner. Although the natural ligand of the Glucocorticoid Receptor, glucocorticoids (GC) represent only some of the multiple ligands for GR. Xenobiotics, ubiquitous in the environment, bind to GR and are also capable of activating or repressing GR gene expression, thereby modulating GR cell and tissue-specific downstream effects in a multitude of ways that include responses to inflammatory, allergic, metabolic, neoplastic and autoimmune processes. Many xenobiotics, if inadequately metabolized by xenobiotic metabolizing enzymes and not wholly eliminated, could have deleterious toxic effects with potentially lethal consequences. This review examines GR, the genomic and non-genomic actions of natural and synthetic GC and the body's handling of xenobiotic compounds, before reviewing what is presently known about GR's interactions with many of the more commonly encountered and some of the less well known GR-associated xenobiotics. GR promiscuity and crosstalk with other signaling pathways is discussed, alongside novel roles for GR that include mood disorder and addiction. A knowledge of GR interactions with xenobiotics is increasingly relevant when considering aging populations and the related prevalence of neoplastic disease, together with growing concerns around human exposure to mixtures of chemicals in the environment. Furthermore, escalating rates of obesity, Type 2 diabetes; autoimmune, allergy, addiction and mood disorder-related pathologies, require novel targeted interventions and GR appears a promising pharmacological candidate. - Highlights: • Biological impact of xenobiotics acting through Glucocorticoid Receptor. • Promiscuity of Glucocorticoid

  2. Xenobiotics and the Glucocorticoid Receptor

    Energy Technology Data Exchange (ETDEWEB)

    Gulliver, Linda S M, E-mail: linda.gulliver@otago.ac.nz

    2017-03-15

    Glucocorticoid Receptor (GR) is present in virtually every human cell type. Representing a nuclear receptor superfamily, GR has several different isoforms essentially acting as ligand-dependent transcription factors, regulating glucocorticoid-responsive gene expression in both a positive and a negative manner. Although the natural ligand of the Glucocorticoid Receptor, glucocorticoids (GC) represent only some of the multiple ligands for GR. Xenobiotics, ubiquitous in the environment, bind to GR and are also capable of activating or repressing GR gene expression, thereby modulating GR cell and tissue-specific downstream effects in a multitude of ways that include responses to inflammatory, allergic, metabolic, neoplastic and autoimmune processes. Many xenobiotics, if inadequately metabolized by xenobiotic metabolizing enzymes and not wholly eliminated, could have deleterious toxic effects with potentially lethal consequences. This review examines GR, the genomic and non-genomic actions of natural and synthetic GC and the body's handling of xenobiotic compounds, before reviewing what is presently known about GR's interactions with many of the more commonly encountered and some of the less well known GR-associated xenobiotics. GR promiscuity and crosstalk with other signaling pathways is discussed, alongside novel roles for GR that include mood disorder and addiction. A knowledge of GR interactions with xenobiotics is increasingly relevant when considering aging populations and the related prevalence of neoplastic disease, together with growing concerns around human exposure to mixtures of chemicals in the environment. Furthermore, escalating rates of obesity, Type 2 diabetes; autoimmune, allergy, addiction and mood disorder-related pathologies, require novel targeted interventions and GR appears a promising pharmacological candidate. - Highlights: • Biological impact of xenobiotics acting through Glucocorticoid Receptor. • Promiscuity of Glucocorticoid

  3. Nuclear Receptors, RXR, and the Big Bang.

    Science.gov (United States)

    Evans, Ronald M; Mangelsdorf, David J

    2014-03-27

    Isolation of genes encoding the receptors for steroids, retinoids, vitamin D, and thyroid hormone and their structural and functional analysis revealed an evolutionarily conserved template for nuclear hormone receptors. This discovery sparked identification of numerous genes encoding related proteins, termed orphan receptors. Characterization of these orphan receptors and, in particular, of the retinoid X receptor (RXR) positioned nuclear receptors at the epicenter of the "Big Bang" of molecular endocrinology. This Review provides a personal perspective on nuclear receptors and explores their integrated and coordinated signaling networks that are essential for multicellular life, highlighting the RXR heterodimer and its associated ligands and transcriptional mechanism. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Fibroblast growth factor receptors in breast cancer.

    Science.gov (United States)

    Wang, Shuwei; Ding, Zhongyang

    2017-05-01

    Fibroblast growth factor receptors are growth factor receptor tyrosine kinases, exerting their roles in embryogenesis, tissue homeostasis, and development of breast cancer. Recent genetic studies have identified some subtypes of fibroblast growth factor receptors as strong genetic loci associated with breast cancer. In this article, we review the recent epidemiological findings and experiment results of fibroblast growth factor receptors in breast cancer. First, we summarized the structure and physiological function of fibroblast growth factor receptors in humans. Then, we discussed the common genetic variations in fibroblast growth factor receptors that affect breast cancer risk. In addition, we also introduced the potential roles of each fibroblast growth factor receptors isoform in breast cancer. Finally, we explored the potential therapeutics targeting fibroblast growth factor receptors for breast cancer. Based on the biological mechanisms of fibroblast growth factor receptors leading to the pathogenesis in breast cancer, targeting fibroblast growth factor receptors may provide new opportunities for breast cancer therapeutic strategies.

  5. Prognostic Value of Estrogen Receptor alpha and Progesterone Receptor Conversion in Distant Breast Cancer Metastases

    NARCIS (Netherlands)

    Hoefnagel, Laurien D. C.; Moelans, Cathy B.; Meijer, S. L.; van Slooten, Henk-Jan; Wesseling, Pieter; Wesseling, Jelle; Westenend, Pieter J.; Bart, Joost; Seldenrijk, Cornelis A.; Nagtegaal, Iris D.; Oudejans, Joost; van der Valk, Paul; van Gils, Carla H.; van der Wall, Elsken; van Diest, Paul J.

    2012-01-01

    BACKGROUND: Changes in the receptor profile of primary breast cancers to their metastases (receptor conversion) have been described for the estrogen receptor alpha (ER alpha) and progesterone receptor (PR). The purpose of this study was to evaluate the impact of receptor conversion for ER alpha and

  6. Expression of GABAergic receptors in mouse taste receptor cells.

    Directory of Open Access Journals (Sweden)

    Margaret R Starostik

    Full Text Available BACKGROUND: Multiple excitatory neurotransmitters have been identified in the mammalian taste transduction, with few studies focused on inhibitory neurotransmitters. Since the synthetic enzyme glutamate decarboxylase (GAD for gamma-aminobutyric acid (GABA is expressed in a subset of mouse taste cells, we hypothesized that other components of the GABA signaling pathway are likely expressed in this system. GABA signaling is initiated by the activation of either ionotropic receptors (GABA(A and GABA(C or metabotropic receptors (GABA(B while it is terminated by the re-uptake of GABA through transporters (GATs. METHODOLOGY/PRINCIPAL FINDINGS: Using reverse transcriptase-PCR (RT-PCR analysis, we investigated the expression of different GABA signaling molecules in the mouse taste system. Taste receptor cells (TRCs in the circumvallate papillae express multiple subunits of the GABA(A and GABA(B receptors as well as multiple GATs. Immunocytochemical analyses examined the distribution of the GABA machinery in the circumvallate papillae. Both GABA(A-and GABA(B- immunoreactivity were detected in the peripheral taste receptor cells. We also used transgenic mice that express green fluorescent protein (GFP in either the Type II taste cells, which can respond to bitter, sweet or umami taste stimuli, or in the Type III GAD67 expressing taste cells. Thus, we were able to identify that GABAergic receptors are expressed in some Type II and Type III taste cells. Mouse GAT4 labeling was concentrated in the cells surrounding the taste buds with a few positively labeled TRCs at the margins of the taste buds. CONCLUSIONS/SIGNIFICANCE: The presence of GABAergic receptors localized on Type II and Type III taste cells suggests that GABA is likely modulating evoked taste responses in the mouse taste bud.

  7. Toll-like receptors in neonatal sepsis.

    LENUS (Irish Health Repository)

    O'Hare, Fiona M

    2013-06-01

    Toll-like receptors are vital transmembrane receptors that initiate the innate immune response to many micro-organisms. The discovery of these receptors has improved our understanding of host-pathogen interactions, and these receptors play an important role in the pathogenesis of multiple neonatal conditions such as sepsis and brain injury. Toll-like receptors, especially TLRs 2 and 4, are associated with necrotizing enterocolitis, periventricular leukomalacia and sepsis.

  8. Studies on insulin receptor, 2

    International Nuclear Information System (INIS)

    Sakai, Yukio

    1979-01-01

    The present study is to investigate an influence of starvation and high fat diet on insulin receptor of the plasma membrane by means of radioreceptor assay using 125 I-labelled insulin. Male guinea pigs of Hartley strain were employed for the starvation study, and 125 I-insulin binding capacity on the plasma membrane of the liver and kidney was determined at 24, 48 and 72 hours of the fast after the last meal. Male rats of Wistar strain were employed for the high fat study where the diet containing 35% of butter was fed ad libitum for 38 or 68 days. The animals were killed at the fast of 12 hours, and 125 I-insulin binding capacity on the plasma membrane of the liver was determined. The results obtained are summarized as follows: 1) An increase in 125 I-insulin binding capacity on the plasma membrane of the liver and kidney was observed by the starvation for 24 to 72 hours. 2) The mechanism of the increase by starvation was considered to be different by the organs; it was due to an increase in number of insulin receptor in the liver, and due to an increase in affinity of insulin receptor in the kidney. 3) In non-obese rats fed with high fat diet, the number of insulin receptor on the liver plasma membrane showed a decrease, and this observation clearly indicated that the decrease in number of the receptor did not depend on the obesity. 4) Obese rats also fed with high fat diet presented a decrease in number of insulin receptor without an elevation of insulin levels in the circulating blood. This indicated that at least in the obese rats fed with high fat diet, the decrease in number of the receptor was not due to hyperinsulinemia. (author)

  9. Purinergic Receptors in Ocular Inflammation

    Directory of Open Access Journals (Sweden)

    Ana Guzman-Aranguez

    2014-01-01

    Full Text Available Inflammation is a complex process that implies the interaction between cells and molecular mediators, which, when not properly “tuned,” can lead to disease. When inflammation affects the eye, it can produce severe disorders affecting the superficial and internal parts of the visual organ. The nucleoside adenosine and nucleotides including adenine mononucleotides like ADP and ATP and dinucleotides such as P1,P4-diadenosine tetraphosphate (Ap4A, and P1,P5-diadenosine pentaphosphate (Ap5A are present in different ocular locations and therefore they may contribute/modulate inflammatory processes. Adenosine receptors, in particular A2A adenosine receptors, present anti-inflammatory action in acute and chronic retinal inflammation. Regarding the A3 receptor, selective agonists like N6-(3-iodobenzyl-5′-N-methylcarboxamidoadenosine (CF101 have been used for the treatment of inflammatory ophthalmic diseases such as dry eye and uveoretinitis. Sideways, diverse stimuli (sensory stimulation, large intraocular pressure increases can produce a release of ATP from ocular sensory innervation or after injury to ocular tissues. Then, ATP will activate purinergic P2 receptors present in sensory nerve endings, the iris, the ciliary body, or other tissues surrounding the anterior chamber of the eye to produce uveitis/endophthalmitis. In summary, adenosine and nucleotides can activate receptors in ocular structures susceptible to suffer from inflammatory processes. This involvement suggests the possible use of purinergic agonists and antagonists as therapeutic targets for ocular inflammation.

  10. Scavenger receptors in homeostasis and immunity.

    Science.gov (United States)

    Canton, Johnathan; Neculai, Dante; Grinstein, Sergio

    2013-09-01

    Scavenger receptors were originally identified by their ability to recognize and to remove modified lipoproteins; however, it is now appreciated that they carry out a striking range of functions, including pathogen clearance, lipid transport, the transport of cargo within the cell and even functioning as taste receptors. The large repertoire of ligands recognized by scavenger receptors and their broad range of functions are not only due to the wide range of receptors that constitute this family but also to their ability to partner with various co-receptors. The ability of individual scavenger receptors to associate with different co-receptors makes their responsiveness extremely versatile. This Review highlights recent insights into the structural features that determine the function of scavenger receptors and the emerging role that these receptors have in immune responses, notably in macrophage polarization and in the pathogenesis of diseases such as atherosclerosis and Alzheimer's disease.

  11. Photo-antagonism of the GABAA receptor.

    Science.gov (United States)

    Mortensen, Martin; Iqbal, Favaad; Pandurangan, Arun P; Hannan, Saad; Huckvale, Rosemary; Topf, Maya; Baker, James R; Smart, Trevor G

    2014-07-29

    Neurotransmitter receptor trafficking is fundamentally important for synaptic transmission and neural network activity. GABAA receptors and inhibitory synapses are vital components of brain function, yet much of our knowledge regarding receptor mobility and function at inhibitory synapses is derived indirectly from using recombinant receptors, antibody-tagged native receptors and pharmacological treatments. Here we describe the use of a set of research tools that can irreversibly bind to and affect the function of recombinant and neuronal GABAA receptors following ultraviolet photoactivation. These compounds are based on the competitive antagonist gabazine and incorporate a variety of photoactive groups. By using site-directed mutagenesis and ligand-docking studies, they reveal new areas of the GABA binding site at the interface between receptor β and α subunits. These compounds enable the selected inactivation of native GABAA receptor populations providing new insight into the function of inhibitory synapses and extrasynaptic receptors in controlling neuronal excitation.

  12. Comparison of Secondary School Mathematics Teacher Training Programs in Turkey and Germany [Türkiye ve Almanya’nın Ortaokul Matematik Öğretmeni Yetiştirme Programlarının Karşılaştırması

    Directory of Open Access Journals (Sweden)

    Adnan Baki

    2016-04-01

    Full Text Available The purpose of this study is to compare secondary school mathematics teacher training programs in Turkey and Germany in terms of entry requirements, training time, professional appointment process of the teacher candidates. Due to the nature of comparative studies documents are obtained from two different sources of data and descriptive analysis was conducted. In the stage of data collection the existing practices about teacher training in Germany and Turkey, books, magazines, printed resources such as scientific articles were used. According to the comparative findings the teacher training programs in Turkey are trying to obtain the needed subject area knowledge and pedagogical content knowledge theoretically. In Germany the needed knowledge are trying to give in a more practical way. On the other hand, both countries are different from each other in terms of entry conditions to teacher training institutions and conditions of appointment of the profession. in Germany teacher candidates go through many processes to be appointed as a noble teacher. It is seen that teacher candidates in Turkey have less time and opportunity in terms of teacher training and practice. [Bu çalışmada, Türkiye ve Almanya’daki ortaokul matematik öğretmeni yetiştirme uygulamaları karşılaştırmalı bir yaklaşımla öğretim programları, giriş koşulları, öğretim süreleri, mesleğe atanma koşulları ve aday öğretmenlik süreçleri boyutlarından incelenmektedir. Karşılaştırmalı çalışmaların doğası gereği iki farklı kaynağın dokümanları üzerinden gidilerek veriler elde edilmiş ve betimsel analizler yapılmıştır. Verilerin toplanması aşamasında; Almanya ve Türkiye’deki mevcut öğretmen yetiştirme uygulamalarıyla ilgili tez, kitap, dergi, makale gibi basılı bilimsel kaynaklardan yararlanılmıştır. Elde edilen karşılaştırmalı bulgulara göre, Türkiye’nin öğretmen yetiştirme programlarında öğretmen aday

  13. Üstün Yetenekli Çocukları Belirlemede Öğretmen Öncelikleri: İkili Karşılaştırma Yöntemiyle Bir Ölçekleme Çalışması

    Directory of Open Access Journals (Sweden)

    Eren Halil Özberk

    2016-08-01

    Full Text Available Bu çalışmanın amacı üstün yetenekli çocukları belirlemede öğretmen önceliklerinin tespit edilmesidir. Bu doğrultuda alanyazına ve uzman görüşüne dayalı olarak üstün yetenekli bireylere ait özellikler belirlenmiş, ardından bu öğrencileri seçmede en önemli referans kaynağı olan öğretmenlere bu kriterler sunularak onların görüşlerine göre ölçekleme yöntemi ile önem dereceleri tespit edilmiş ve bu önem derecelerinin öğretmenlerin demografik özelliklerine göre nasıl değişkenlik gösterdiği incelenmiştir. Bu amaçla ölçekleme çalışmasında üstün yetenekli öğrencilerin özellikleri yedi ifade altında toplanmıştır. Araştırmada Ankara ili merkez ilçelerinde bulunan 785 öğretmenden bu 7 özelliği ikili karşılaştırma yaparak sıralamaları istenmiştir. Yapılan ölçekleme işlemi sonunda öğretmenlerin üstün yetenekli çocukları belirlemede ilk önce tercih ettiği özellik, çevreye ve sosyal olaylara karşı duyarlı olması, son tercih ettiği özellik ise arkadaş çevresinde liderlik özelliğine sahip olması olmuştur. Öğretmenlerin demografik özelliklerine göre önem sıralamasında ise üstün yetenekli çocukları belirlemede ilk tercih edilen özellik, çevreye ve sosyal olaylara karşı duyarlı olması olmuştur. The aim of the research is to determine teacher priorities on identifying gifted children. The study is based on the principle of comparison of seven different specifications which were determined by literature and professionals majored in gifted education according to the judgments of the primary and secondary school teachers using pairwise comparison method according to various demographic variable. In that particular scaling study, specifications of gifted children have been summarized in seven statements. These seven statements have been asked 785 teachers in Ankara province to compare by using pairwise comparison. As a result of scaling study

  14. Effect of the non-NMDA receptor antagonist GYKI 52466 on the microdialysate and tissue concentrations of amino acids following transient forebrain ischaemia.

    Science.gov (United States)

    Arvin, B; Lekieffre, D; Graham, J L; Moncada, C; Chapman, A G; Meldrum, B S

    1994-04-01

    The effect of the non-N-methyl-D-aspartate (non-NMDA) receptor antagonist 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride (GYKI 52466) on ischaemia-induced changes in the microdialysate and tissue concentrations of glutamate, aspartate, and gamma-aminobutyric acid (GABA) was studied in rats. Twenty minutes of four-vessel occlusion resulted in a transient increase in microdialysate levels of glutamate, aspartate, and GABA in striatum, cortex, and hippocampus. Administration of GYKI 52466 (10 mg/kg bolus + 10 mg/kg/60 min intravenously starting 20 min before onset of ischaemia) inhibited ischaemia-induced increases in microdialysate glutamate and GABA in striatum without affecting the increases in hippocampus or cortex. Twenty minutes of four-vessel occlusion resulted in immediate small decreases and larger delayed (72 h) decreases in tissue levels of glutamate and aspartate. Transient increases in tissue levels of GABA were shown in all three structures at the end of the ischaemic period. At 72 h, after the ischaemic period, significantly reduced GABA levels were observed in striatum and hippocampus. GYKI 52466, given under identical conditions as above, augmented the ischaemia-induced decrease in striatal tissue levels of glutamate and aspartate, without significantly affecting the decreases in hippocampus and cortex. Twenty minutes of ischaemia resulted in a large increase in microdialysate dopamine in striatum. GYKI 52466 failed to inhibit this increase. Kainic acid (500 microM infused through the probe for 20 min) caused increases in microdialysate glutamate and aspartate in the striatum. GYKI 52466 (10 mg/kg bolus + 10 mg/kg/60 min) completely inhibited the kainic acid-induced glutamate release. In conclusion, the action of the non-NMDA antagonist, GYKI 52466, in the striatum is different from that in the cortex and hippocampus. The inhibition by GYKI 52466 of ischaemia-induced and kainate-induced increases in microdialysate

  15. TAM receptor signaling in development.

    Science.gov (United States)

    Burstyn-Cohen, Tal

    2017-01-01

    TYRO3, AXL and MERTK comprise the TAM family of receptor protein tyrosine kinases. Activated by their ligands, protein S (PROS1) and growth-arrest-specific 6 (GAS6), they mediate numerous cellular functions throughout development and adulthood. Expressed by a myriad of cell types and tissues, they have been implicated in homeostatic regulation of the immune, nervous, vascular, bone and reproductive systems. The loss-of-function of TAM signaling in adult tissues culminates in the destruction of tissue homeostasis and diseased states, while TAM gain-of-function in various tumors promotes cancer phenotypes. Combinatorial ligand-receptor interactions may elicit different molecular and cellular responses. Many of the TAM regulatory functions are essentially developmental, taking place both during embryogenesis and postnatally. This review highlights current knowledge on the role of TAM receptors and their ligands during these developmental processes in the immune, nervous, vascular and reproductive systems.

  16. How calcium makes endocytic receptors attractive

    DEFF Research Database (Denmark)

    Andersen, Christian B F; Moestrup, Søren K

    2014-01-01

    of the receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable...... 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect...... the receptor calcium sites....

  17. Sürtünme Karıştırma Kaynak Yöntemiyle Birleştirilen Farklı Tipteki Alüminyum Bağlantıların Tahribatlı ve Tahribatsız Muayenesi

    Directory of Open Access Journals (Sweden)

    Furkan SARSILMAZ

    2009-04-01

    Full Text Available Bu çalışmada farklı kimyasal ve mekanik özelliklere sahip AA 5754 (AlMg3 ile AA 5083 (AlMg4,5Mn0,7 alüminyum alaşım levhaları, günümüzde yeni geliştirilen sürtünme karıştırma kaynak (SKK yöntemiyle birleştirilmiştir. Çalışmada farklı devir ve ilerleme hızlarının, kaynaklı bağlantıların mekanik özelliklerini belirlemek amacıyla tahribatlı (çekme, çentik darbe, ve yorulma ve tahribatsız (floroskopik testler uygulanmıştır. Tahribatlı testler sonucunda farklı kaynak dönme ve ilerleme hızlarının, bağlantının mekanik test sonuçlarını etkilediği belirlenmiştir. Tahribatsız test sonucunda ise düşük devir sayısının ve yüksek ilerleme hızının, kaynak bölgesinde yetersiz birleşme meydana getirmesiyle, dikiş boyunca bölgesel porozite, tünel ve boşluklu bölgelerin oluştuğu görülmüştür. En iyi mekanik test sonucunu, 1400 devir dönme hızı ve 250 mm/dak ilerleme hızı işlem parametresi ile birleştirilen numune sergilemiştir. Anahtar Kelimeler: Sürtünme Karıştırma Kaynağı, Alüminyum Alaşımları, Tahribatlı Ve Tahribatsız Muayene, Kaynak Bölgesi

  18. Marmara Bölgesi'nde Arpa açık rastığı (Ustilago nuda hordei “Jens.â€? Rostr. Schaffn.)'na karşı arpa çeşit ve hatlarının reaksiyonlarının tespiti üzerinde araştırmalar.

    OpenAIRE

    Gümüştekin, H.; Akın, K.

    2008-01-01

    Arpa çeşit ve hatlarının, arpa açık rastık hastalığı (Ustilago nuda hordei “Jens.â€? Rostr. Schaffn.)'na karşı göstermiş olduğu reaksiyonları tespit etmek amacı ile bu çalışma 1994 yılında başlamıştır. 1994 Yılında 14 arpa çeşit ve hattı, 1995 yılında 23 arpa çeşit ve hattı kullanılmıştır. Denemelerde kullanılan 37 çeşit ve hattan 27'si hastalığa karşı dayanıklı (R) bulunurken, 10'u hassas (S) bulunmuştur.

  19. The lactate receptor, G-protein-coupled receptor 81/hydroxycarboxylic acid receptor 1

    DEFF Research Database (Denmark)

    Morland, Cecilie; Lauritzen, Knut Huso; Puchades, Maja

    2015-01-01

    We have proposed that lactate is a “volume transmitter” in the brain and underpinned this by showing that the lactate receptor, G-protein-coupled receptor 81 (GPR81, also known as HCA1 or HCAR1), which promotes lipid storage in adipocytes, is also active in the mammalian brain. This includes......, energy metabolism, and energy substrate availability, including a glucose- and glycogen-saving response. HCAR1 may contribute to optimizing the cAMP concentration. For instance, in the prefrontal cortex, excessively high cAMP levels are implicated in impaired cognition in old age, fatigue, stress...

  20. Stability of solubilized benzodiazepine receptors

    NARCIS (Netherlands)

    Janssen, M.J; Ensing, K; de Zeeuw, R.A

    1997-01-01

    According to the observations of other researchers, benzodiazepine receptors solubilized with sodium deoxycholate are unstable, but stability can be improved by exchanging deoxycholate for Triton X-100. In our experiments we conclude that the choice of detergent is not the restrictive factor for the

  1. Serum transferrin receptor in polycythemia.

    Science.gov (United States)

    Manteiga, R; Remacha, A F; Sardà, M P; Ubeda, J

    1998-10-01

    We measured serum transferrin receptor (sTfR) levels in 22 patients with polycythemia vera and in 26 cases of secondary polycythemia. In our study, raised sTfR levels in both polycythemia groups were related to iron deficiency.

  2. FMRFamide receptors of Helix aspersa

    International Nuclear Information System (INIS)

    Payza, K.

    1988-01-01

    A receptor binding assay and an isolated heart bioassay were used to identify and characterize the FMRFamide receptors in Helix. In the heart bioassay, FMRFamide increased myocardial contraction force. A potent FMRFamide analog, desaminoTyr-Phe-norLeu-arg-Phe-amide (daYFnLRFamide), was used as a radioiodinated receptor ligand. The high affinity binding of 125 I-daYFnLRFamide at 0 degree C to Helix brain membranes was reversible, saturable, pH-dependent and specific, with a K D of 13-14 nM. A lower affinity (245 nM) site was also observed. Radioligand binding sites were also identified in the heart, male reproductive organs and digestive organs. The structure-activity relations (SAR) of cardiostimulation correlated with the specificity of 125 I-daYFnLRFamide binding to brain and heart receptors. The SAR were similar to those of other molluscan FMRFamide bioassays, except that they showed a marked preference for some analogs with blocked amino-terminals

  3. Pharmacological approach of the receptors

    International Nuclear Information System (INIS)

    Puech, A.J.

    1989-01-01

    This paper explains the three main goals for clinical positron emission tomography (PET) studies: detection of receptor abnormalities in groups of patients to propose therapeutic indication of new ligands; validation of current hypothesis of drug effect; rational clinical drug development specially for dose-finding studies. (H.W.)

  4. Uncompetitive antagonism of AMPA receptors

    DEFF Research Database (Denmark)

    Andersen, Trine F; Tikhonov, Denis B; Bølcho, Ulrik

    2006-01-01

    Philanthotoxins are uncompetitive antagonists of Ca2+-permeable AMPA receptors presumed to bind to the pore-forming region, but a detailed molecular mechanism for this interaction is missing. Here a small library of novel philanthotoxins was designed and synthesized using a solid-phase strategy. ...

  5. NMDA receptors and memory encoding.

    Science.gov (United States)

    Morris, Richard G M

    2013-11-01

    It is humbling to think that 30 years have passed since the paper by Collingridge, Kehl and McLennan showing that one of Jeff Watkins most interesting compounds, R-2-amino-5-phosphonopentanoate (d-AP5), blocked the induction of long-term potentiation in vitro at synapses from area CA3 of the hippocampus to CA1 without apparent effect on baseline synaptic transmission (Collingridge et al., 1983). This dissociation was one of the key triggers for an explosion of interest in glutamate receptors, and much has been discovered since that collectively contributes to our contemporary understanding of glutamatergic synapses - their biophysics and subunit composition, of the agonists and antagonists acting on them, and their diverse functions in different networks of the brain and spinal cord. It can be fairly said that Collingridge et al.'s (1983) observation was the stimulus that has led, on the one hand, to structural biological work at the atomic scale describing the key features of NMDA receptors that enables their coincidence function to happen; and, on the other, to work with whole animals investigating the contributions that calcium signalling via this receptor can have on rhythmical activities controlled by spinal circuits, memory encoding in the hippocampus (the topic of this article), visual cortical plasticity, sensitization in pain, and other functions. In this article, I lay out how my then interest in long-term potentiation (LTP) as a model of memory enabled me to recognise the importance of Collingridge et al.'s discovery - and how I and my colleagues endeavoured to take things forward in the area of learning and memory. This is in some respects a personal story, and I tell it as such. The idea that NMDA receptor activation is essential for memory encoding, though not for storage, took time to develop and to be accepted. Along the way, there have been confusions, challenges, and surprises surrounding the idea that activation of NMDA receptors can

  6. Ror receptor tyrosine kinases: orphans no more

    OpenAIRE

    Green, Jennifer L.; Kuntz, Steven G.; Sternberg, Paul W.

    2008-01-01

    Receptor tyrosine kinase-like orphan receptor (Ror) proteins are a conserved family of tyrosine kinase receptors that function in developmental processes including skeletal and neuronal development, cell movement and cell polarity. Although Ror proteins were originally named because the associated ligand and signaling pathway were unknown, recent studies in multiple species have now established that Ror proteins are Wnt receptors. Depending on the cellular context, Ror proteins can either act...

  7. Benzodiazepine receptor antagonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C

    2004-01-01

    Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy....

  8. Synaptic Bistability Due to Nucleation and Evaporation of Receptor Clusters

    KAUST Repository

    Burlakov, V. M.; Emptage, N.; Goriely, A.; Bressloff, P. C.

    2012-01-01

    interacting receptors and is stabilized against clustering by a high nucleation barrier. The other state contains a receptor gas in equilibrium with a large cluster of immobile receptors, which is stabilized by the turnover rate of receptors into and out

  9. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, B. R.; Korte, S. M.; Buwalda, B.; La Fleur, S. E.; Bohus, B.; Luiten, P. G.

    1998-01-01

    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  10. Repeated blockade of mineralocorticoid receptors, but not of glucocorticoid receptors impairs food rewarded spatial learning

    NARCIS (Netherlands)

    Douma, BRK; Korte, SM; Buwalda, B; la Fleur, SE; Bohus, B; Luiten, PGM

    Corticosteroids from the adrenal cortex influence a variety of behaviours including cognition, learning and memory. These hormones act via two intracellular receptors, the mineralo-corticoid receptor (MR) and the glucocorticoid receptor (GR). These two receptor types display a high concentration and

  11. Receptores de progesterona en meningioma.

    Directory of Open Access Journals (Sweden)

    Herminio Ojeda Di Ninno

    1995-04-01

    Full Text Available Objetivo: Determinar la presencia de los receptores de progesterona en meningiomas y su frecuencia mediante la inmunohistoquímica. Material y Métodos: Se analizaron 24 muestras provenientes de pacientes intervenidos quirúrgicamente en el Instituto Nacional de Enfermedades Neoplásicas entre los años 1990 y 1992 con diagnóstico anatomopatológico de meningioma. La determinación de los receptores se hizo mediante una técnica de inmunohistoquímica rápida que permite el estudio de tejidos fijados previamente en parafina. Resultados: De los 24 casos estudiados, nueve resultaron ser positivos en la determinación de receptores de progesterona (37%. Se pudo observar un marcado predominio dentro del grupo femenino quienes constituyeron 8/9 casos positivos. Conclusiones: El empleo de esta reciente técnica de inmunohistoquímica aplicada a tejido de fijado en parafina, nos ha permitido confirmar la presencia de receptores de progesterona en meningiomas con una frecuencia elevada que creemos amerita un estudio más amplio de manera sistemática que incluya la intervención terapéutica mediante el uso de antiprogestágenos, como el Mifepristone o RU 486. De este estudio podrían beneficiarse no sólo pacientes operados recientemente sino aquellos que, intervenidos en el pasado sean detectados como portadores de receptores de progesterona mediante la aplicación de esta novedosa técnica (Rev Med Hered 1995; 6: 121-130.

  12. A new family of insect tyramine receptors

    DEFF Research Database (Denmark)

    Cazzamali, Giuseppe; Klærke, Dan Arne; Grimmelikhuijzen, Cornelis J P

    2005-01-01

    in the genomic databases from the malaria mosquito Anopheles gambiae and the honeybee Apis mellifera. These four tyramine or tyramine-like receptors constitute a new receptor family that is phylogenetically distinct from the previously identified insect octopamine/tyramine receptors. The Drosophila tyramine...

  13. Imaging of receptors in clinical neurosciences

    NARCIS (Netherlands)

    Korf, J

    This article deals with the question why should one determine receptors in the brain with positron and single photon emission tomography (PET and SPECT, respectively). Radiopharmaceuticals for a wide variety of receptors are available now. Receptors studies with PET and SPECT have thus far focused

  14. Receptor conversion in distant breast cancer metastases

    NARCIS (Netherlands)

    Hoefnagel, L.D.C.

    2013-01-01

    The routine pathological work-up of breast cancer includes the evaluation of the estrogen receptor (ERα), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) which reveals biological information about the tumour as well as provides predictive biomarkers regarding hormonal

  15. Molecular pharmacology of human NMDA receptors

    DEFF Research Database (Denmark)

    Hedegaard, Maiken; Hansen, Kasper Bø; Andersen, Karen Toftegaard

    2012-01-01

    N-methyl-d-aspartate (NMDA) receptors are ionotropic glutamate receptors that mediate excitatory neurotransmission. NMDA receptors are also important drug targets that are implicated in a number of pathophysiological conditions. To facilitate the transition from lead compounds in pre-clinical ani...

  16. Seçici Özellikteki Farklı Besiyerlerinin bazı Mayaların Meyveli Yoğurttan Geri Kazanımları Amacı ile Karşılaştırılmaları (İngilizce

    Directory of Open Access Journals (Sweden)

    Şule Şenses Ergül

    2015-02-01

    Full Text Available Bu çalışmada, yapay olarak aşılanan meyveli yoğurt örneklerinden bazı mayaların izolasyonu için kullanılabilecek farklı besiyerleri karşılaştırılmıştır. Bu amaçla, kontrol besiyeri olarak malt extract agar ve beş farklı seçici besiyeri kullanılmıştır. Bu besiyerleri; malt extract yeast extract %50 fructose glucose agar, malt extract yeast extract %40 sucrose agar, malt extract yeast extract glucose %0.8 peptone agar, malt extract yeast extract glucose %0.1 peptone agar and potato dextrose %50 sucrose glucose agar’dır. Maya suşları olarak; Zygosaccharomyces rouxii IFO 0487, Zygosaccharomyces bailii IFO 0488 ve Saccharomyces cerevisiae IFO 2359 kullanılmıştır. Uygun inkübasyon süreleri sonunda, besiyerlerinin geri kazanım özellikleri belirlenmiştir. Yapılan istatistiksel değerlendirmeler ve bazı öznel verilere göre, malt extract yeast extract %40 sucrose agar besiyerinin test edilen suşlar için daha iyi sonuç verdiği tespit edilmiştir.

  17. Haşim Bey Mecmuasının “Makam Ve Tonalite Karşılaştırması” Yönünden İncelenmesi The Analysis Of Haşim Bey’s Anthology For “Comparison Of Maqam And Tonality”

    Directory of Open Access Journals (Sweden)

    Gökhan YALÇIN

    2013-07-01

    Full Text Available The first printed source contains Western music theory knowledgeis the second edition of “Mecmûa-i Kârhâ ve Nakışhâ ve Şarkıyât”known as “Hâşim Bey Mecmuası” is published by Hasim Bey in 1864.Another feature of this book is in the description of the Turkish musicmaqams, Hasim Bey compared maqams with Western music tonalsequences and identified them. This comparison is completely rejectedby some musicologists, has been considered by some as the first. In therelated researchs, it is confirmed that the translation of Hasim Bey’santhology has been done but the analysis of the chapter about Westernmusic theory has not been done. The aim of this study is theexamination relevant departments of the Western music in Hasim Bey’santhology and to reveal what are the similarities in the comparison ofTurkish music maqams with Western music tonal sequences.According to the findings, the similarities are classified "accordingto the tonic note”, according to the progress and behaviour”, "accordingto the used alterative markings" and "similar in all aspects". Theharmonic analysis of the maqamic polyphonic works composed in thesame period and latter has been done and according to the the usedharmony the tonalities were also in good agreement with similarities ofHasim Bey’s. Furthermore, as a theory book in this anthology thecomparison is used as a method to introduce and teach the tonalities orto introduce and teach the maqams. Afterwards, it is seen that this kindof works are used as a method especially for teaching the Westernmusic notes. 1864’te Haşim Bey tarafından yayınlanan ve “Hâşim Bey Mecmuası” olarak bilinen “Mecmûa-i Kârhâ ve Nakışhâ ve Şarkıyât” adlı eserinin ikinci baskısı Batı müzik teorisi bilgileri içeren ilk basılı kaynaktır. Bu kitabın başka bir özelliği de Türk müziği makamlarının tarifinde Haşim Bey’in makamları Batı müziği tonal dizileri ile karşılaştırmış ve

  18. Sigara karşıtı televizyon reklamlarında kullanılan korku çekiciliği faktörü etkinliğinin beyin görüntüleme tekniği ile ölçümü

    OpenAIRE

    Gürdin, Bahar

    2016-01-01

    Reklam etkinliği işletmelerin çok hassas bir şekilde üzerinde durduğu konulardan bir tanesidir. Reklamların etkinliğinin artırılabilmesi için çeşitli çekicilik faktörleri kullanılmaktadır. Korku çekiciliği faktörü de bu faktörlerden bir tanesidir. Çalışma, sigara karşıtı reklamlarda kullanılan korku çekiciliği faktörünün etkinliği üzerinedir. Etkinliğin ölçümü için fNIRS cihazından yararlanılmış ve bu sayede beyindeki kanın yoğunlaşma durumuna göre deneklerin bu tarz reklamlardan etkilenme dü...

  19. Some theoretical aspects of hormone receptor determination

    International Nuclear Information System (INIS)

    Sluiter, W.J.

    1981-01-01

    Suitable antisera for determination of hormone receptors are not available for the majority of hormone receptors. Therefore, the determination of hormone receptors is mostly performed in terms of binding capacity for the appropriate hormone, using radioactive hormone labels. Some theoretical aspects of such a receptor determination are discussed including the length of incubation (total or unoccupied receptor concentration), single point or multiple point (Scatchard) analysis (regarding the influence of other specific binders), the correction procedure for non-specific binding and the influence of the circulating hormone level. (Auth.)

  20. [Ceruloplasmin receptor on human erythrocytes].

    Science.gov (United States)

    Saenko, E L; Basevich, V V; Iaropolov, A I

    1988-08-01

    The structural fragments of the human ceruloplasmin (CP) molecule and of erythrocyte receptors which provide for the specific interaction of CP with erythrocytes were identified, and their properties were investigated. The interaction of CP with erythrocytes, both intact and treated with neuroaminidase and proteolytic enzymes (trypsin, chymotrypsin, papaine, pronase E) is described. Experiments with CP reception were performed at 4 degrees C, using [125I]CP and [125I]asialo-CP. The parameters of binding were determined in Scatchard plots. It was demonstrated that the specific binding of CP to erythrocyte receptors is determined by its interaction with two structural sites of the carbohydrate moiety of the CP molecule, i.e., the terminal residues of sialic acids and a site, (formula; see text) located at a large distance from the chain terminus.

  1. NGA/Insulin receptor scanning

    International Nuclear Information System (INIS)

    Kurtaran, A.; Virgolini, I.

    1994-01-01

    Tc-99m-galactosyl-neoglycoalbumin (NGA) is one of the first receptor-based radiopharmaceuticals which specifically recognizes the hepatic binding protein (HBP) located on the surface of the hepatocytes. The exclusive interactin of NGA with HBP provided the basis for a kinetic model for the evaluation hepatocellular function. During the last years we have used NGA in more than 300 patients with various liver diseases including liver cirrhosis (Stages Child A to Child C), viral hepatitis, and carcinomas. In these studies, the calculated HBP densities, after i.v.-injection of Tc-99m-NGA, significantly correlated with the clinical course of the diseases. Furthermore, similar to conventional Tc-colloid, NGA provided excellent demonstration of 'cold spots' for hepatic masses. In a further approach we used another hepatocyte receptor-seeking radioligand, I-123-Tyr-A14- insulin, and found, that its in vitro-binding to hepatocellular carcinomas is greatly enhanced over normal hepatic tissue. On this basis, we developed a double-tracer method using NGA and insulin in a single study. Thus, areas of 'cold spots' identifying hepatic masses on NGA scans, take up I-123-Tyr-A14-insulin immediately after i.v.-injection. This was true for hepatocellular hepatomas, but not for adenocarcinomas. In conclusion, NGA/insulin receptor scanning could be a novel and save method for the demonstration of hepatocellular hepatomas. (author)

  2. PAF receptor structure: a hypothesis.

    Science.gov (United States)

    Godfroid, J J; Dive, G; Lamotte-Brasseur, J; Batt, J P; Heymans, F

    1991-12-01

    Different hypotheses of the structure of platelet-activating factor (PAF) receptor based on structure-activity relationships of agonists and antagonists are reviewed. For an agonistic effect, strong hydrophobic interactions and an ether function are required in position-1 of the glycerol backbone; chain length limitations and steric hindrance demand a small group in position-2. The unusual structural properties of non-PAF-like antagonists required 3-D electrostatic potential calculations. This method applied to seven potent antagonists suggests a strong "Cache-orielles" (ear-muff) effect, i.e., two strong electronegative wells (isocontour at -10 Kcal/mole) are located at 180 degrees to each other and at a relatively constant distance. Initial consideration of the "Cache-oreilles" effect implied the structure of a bipolarized cylinder of 10-12 A diameter for the receptor. However, very recent results on studies with agonists and antagonists structurally similar to PAF suggest that the receptor may in fact be a multi-polarized cylinder.

  3. NGA/Insulin receptor scanning

    Energy Technology Data Exchange (ETDEWEB)

    Kurtaran, A; Virgolini, I [Vienna Univ. (Austria). Abt. fuer Nuklearmedizin; Angelberger, P [Ludwig Boltzmann-Institut fuer Nuklearmedizin, Vienna (Austria)

    1994-10-01

    Tc-99m-galactosyl-neoglycoalbumin (NGA) is one of the first receptor-based radiopharmaceuticals which specifically recognizes the hepatic binding protein (HBP) located on the surface of the hepatocytes. The exclusive interactin of NGA with HBP provided the basis for a kinetic model for the evaluation hepatocellular function. During the last years we have used NGA in more than 300 patients with various liver diseases including liver cirrhosis (Stages Child A to Child C), viral hepatitis, and carcinomas. In these studies, the calculated HBP densities, after i.v.-injection of Tc-99m-NGA, significantly correlated with the clinical course of the diseases. Furthermore, similar to conventional Tc-colloid, NGA provided excellent demonstration of `cold spots` for hepatic masses. In a further approach we used another hepatocyte receptor-seeking radioligand, I-123-Tyr-A14- insulin, and found, that its in vitro-binding to hepatocellular carcinomas is greatly enhanced over normal hepatic tissue. On this basis, we developed a double-tracer method using NGA and insulin in a single study. Thus, areas of `cold spots` identifying hepatic masses on NGA scans, take up I-123-Tyr-A14-insulin immediately after i.v.-injection. This was true for hepatocellular hepatomas, but not for adenocarcinomas. In conclusion, NGA/insulin receptor scanning could be a novel and save method for the demonstration of hepatocellular hepatomas. (author).

  4. Lymphocyte receptors for pertussis toxin

    Energy Technology Data Exchange (ETDEWEB)

    Clark, C.G.; Armstrong, G.D. (Univ. of Alberta, Edmonton (Canada))

    1990-12-01

    We have investigated human T-lymphocyte receptors for pertussis toxin by affinity isolation and photoaffinity labeling procedures. T lymphocytes were obtained from peripheral human blood, surface iodinated, and solubilized in Triton X-100. The iodinated mixture was then passed through pertussis toxin-agarose, and the fractions were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Autoradiography of the fixed, dried gels revealed several bands in the pertussis toxin-bound fraction that were not observed in fractions obtained from histone or fetuin-agarose. Further investigations employed a photoaffinity labeling reagent, sulfosuccinimidyl 2-(p-azido-salicylamido)-1,3'-dithiopropionate, to identify pertussis toxin receptors in freshly isolated peripheral blood monocytic cells, T lymphocytes, and Jurkat cells. In all three cell systems, the pertussis toxin affinity probe specifically labeled a single protein species with an apparent molecular weight of 70,000 that was not observed when the procedure was performed in the presence of excess unmodified pertussis toxin. A protein comparable in molecular weight to the one detected by the photoaffinity labeling technique was also observed among the species that bound to pertussis toxin-agarose. The results suggest that pertussis toxin may bind to a 70,000-Da receptor in human T lymphocytes.

  5. The two-state dimer receptor model: a general model for receptor dimers.

    Science.gov (United States)

    Franco, Rafael; Casadó, Vicent; Mallol, Josefa; Ferrada, Carla; Ferré, Sergi; Fuxe, Kjell; Cortés, Antoni; Ciruela, Francisco; Lluis, Carmen; Canela, Enric I

    2006-06-01

    Nonlinear Scatchard plots are often found for agonist binding to G-protein-coupled receptors. Because there is clear evidence of receptor dimerization, these nonlinear Scatchard plots can reflect cooperativity on agonist binding to the two binding sites in the dimer. According to this, the "two-state dimer receptor model" has been recently derived. In this article, the performance of the model has been analyzed in fitting data of agonist binding to A(1) adenosine receptors, which are an example of receptor displaying concave downward Scatchard plots. Analysis of agonist/antagonist competition data for dopamine D(1) receptors using the two-state dimer receptor model has also been performed. Although fitting to the two-state dimer receptor model was similar to the fitting to the "two-independent-site receptor model", the former is simpler, and a discrimination test selects the two-state dimer receptor model as the best. This model was also very robust in fitting data of estrogen binding to the estrogen receptor, for which Scatchard plots are concave upward. On the one hand, the model would predict the already demonstrated existence of estrogen receptor dimers. On the other hand, the model would predict that concave upward Scatchard plots reflect positive cooperativity, which can be neither predicted nor explained by assuming the existence of two different affinity states. In summary, the two-state dimer receptor model is good for fitting data of binding to dimeric receptors displaying either linear, concave upward, or concave downward Scatchard plots.

  6. Localization of mineralocorticoid receptors at mammalian synapses.

    Directory of Open Access Journals (Sweden)

    Eric M Prager

    Full Text Available In the brain, membrane associated nongenomic steroid receptors can induce fast-acting responses to ion conductance and second messenger systems of neurons. Emerging data suggest that membrane associated glucocorticoid and mineralocorticoid receptors may directly regulate synaptic excitability during times of stress when adrenal hormones are elevated. As the key neuron signaling interface, the synapse is involved in learning and memory, including traumatic memories during times of stress. The lateral amygdala is a key site for synaptic plasticity underlying conditioned fear, which can both trigger and be coincident with the stress response. A large body of electrophysiological data shows rapid regulation of neuronal excitability by steroid hormone receptors. Despite the importance of these receptors, to date, only the glucocorticoid receptor has been anatomically localized to the membrane. We investigated the subcellular sites of mineralocorticoid receptors in the lateral amygdala of the Sprague-Dawley rat. Immunoblot analysis revealed the presence of mineralocorticoid receptors in the amygdala. Using electron microscopy, we found mineralocorticoid receptors expressed at both nuclear including: glutamatergic and GABAergic neurons and extra nuclear sites including: presynaptic terminals, neuronal dendrites, and dendritic spines. Importantly we also observed mineralocorticoid receptors at postsynaptic membrane densities of excitatory synapses. These data provide direct anatomical evidence supporting the concept that, at some synapses, synaptic transmission is regulated by mineralocorticoid receptors. Thus part of the stress signaling response in the brain is a direct modulation of the synapse itself by adrenal steroids.

  7. Protein Connectivity in Chemotaxis Receptor Complexes.

    Directory of Open Access Journals (Sweden)

    Stephan Eismann

    2015-12-01

    Full Text Available The chemotaxis sensory system allows bacteria such as Escherichia coli to swim towards nutrients and away from repellents. The underlying pathway is remarkably sensitive in detecting chemical gradients over a wide range of ambient concentrations. Interactions among receptors, which are predominantly clustered at the cell poles, are crucial to this sensitivity. Although it has been suggested that the kinase CheA and the adapter protein CheW are integral for receptor connectivity, the exact coupling mechanism remains unclear. Here, we present a statistical-mechanics approach to model the receptor linkage mechanism itself, building on nanodisc and electron cryotomography experiments. Specifically, we investigate how the sensing behavior of mixed receptor clusters is affected by variations in the expression levels of CheA and CheW at a constant receptor density in the membrane. Our model compares favorably with dose-response curves from in vivo Förster resonance energy transfer (FRET measurements, demonstrating that the receptor-methylation level has only minor effects on receptor cooperativity. Importantly, our model provides an explanation for the non-intuitive conclusion that the receptor cooperativity decreases with increasing levels of CheA, a core signaling protein associated with the receptors, whereas the receptor cooperativity increases with increasing levels of CheW, a key adapter protein. Finally, we propose an evolutionary advantage as explanation for the recently suggested CheW-only linker structures.

  8. Characterization of astrocytic and neuronal benzodiazepine receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bender, A.S.

    1988-01-01

    Primary cultures of astrocytes and neurons express benzodiazepine receptors. Neuronal benzodiazepine receptors were of high-affinity, K{sub D} values were 7.5-43 nM and the densities of receptors (B{sub max}) were 924-4131 fmol/mg protein. Astrocytes posses a high-affinity benzodiazepine receptor, K{sub D} values were 6.6-13 nM. The B{sub max} values were 6,033-12,000 fmol/mg protein. The pharmacological profile of the neuronal benzodiazepine receptor was that of the central-type benzodiazepine receptor, where clonazepam has a high-affinity and Ro 5-4864 (4{prime}-chlorodiazepam) has a low-affinity. Whereas astrocytic benzoidazepine receptor was characteristic of the so called peripheral-type benzodiazepine receptors, which shows a high-affinity towards Ro 5-4863, and a low-affinity towards clonazepam. The astrocytic benzodiazepine receptors was functionally correlated with voltage dependent calcium channels, since dihydropyridines and benzodiazepines interacted with ({sup 3}H) diazepam and ({sup 3}H) nitrendipine receptors with the same rank order of potency, showing a statistically significant correlation. No such correlation was observed in neurons.

  9. Türkiye ve Almanya’daki Coğrafya Öğretim Programlarının Karşılaştırılması / Comparisons of Geography Teaching Programs in Turkey and Germany

    Directory of Open Access Journals (Sweden)

    Mehmet Fatih KAYA

    2011-06-01

    Full Text Available Bu çalışmada; Türkiye’de 2005, Almanya’da ise 2004 yılından itibaren liselerde uygulanmaya başlanan Coğrafya Öğretim Programları karşılaştırılmıştır. Bu araştırma, lise Coğrafya Öğretim Programları’nın hedef, içerik, öğretme-öğrenme ve değerlendirme süreçlerini tespit etmeye yönelik bir araştırma şeklinde tasarlanmıştır. Araştırma nitel bir desene sahiptir. Araştırmanın evrenini Türkiye ve Almanya’da lise Coğrafya Öğretim Programları oluşturmaktadır. Örneklemini ise Türkiye’deki lise 9. sınıflar, Almanya’da ise nüfus miktarı ve yoğunluğu en fazla olan Nordhrhein-Westfalen eyaletindeki lise 9. sınıflar teşkil etmektedir. Coğrafya Öğretim Programları içerik analizine uygun olarak incelenmiş ve elde edilen bulgular doğrultusunda programlar; hedef, içerik, öğretme-öğrenme süreci ve değerlendirme süreci açısından karşılaştırılmıştır. Yaptığımız araştırmada şu sorulara cevap aranmıştır: Türkiye ve Almanya’daki Coğrafya Öğretim Programı’nın benzer ve farklılıkları nelerdir? Türkiye ve Almanya’daki Coğrafya Öğretim Programı’nın hedef, içerik, öğretme-öğrenme süreci ve değerlendirme süreci açısından olumlu ve olumsuz yönleri nelerdir? Her iki programın da benzerlik göstermekle birlikte birtakım farklılıkları da içerdiği tespit edilmiştir. Elde edilen bulgular ışığında araştırmacılara, öğretmenlere ve program geliştirme uzmanlarına bazı önerilerde bulunulmuştur.

  10. Ücretsiz mevsimsel grip aşılarını yaptıran kişilerin, ücretsiz pandemik grip aşısı karşısındaki tutum ve davranışları

    Directory of Open Access Journals (Sweden)

    Muzaffer Eskiocak

    2011-09-01

    Full Text Available Amaç: Bu çalışma, mevsimsel grip aşısına (MGA ücretsiz erişen insanların tutum ve davranışlarını, yine ücretsiz, ama çeşitli tartışmalara konu olan pandemik grip aşısı (PGA karşısındaki tutum ve davranışlarıyla karşılaştırmak amacıyla yapılmıştır. Yöntem: Araştırma tanımlayıcı tipte bir araştırmadır ve Kırklareli-Evrensekiz Sağlık Ocağı bölgesinde, Şubat,2009–Şubat,2010 tarihleri arasında yürütülmüştür. Çalışma anketi yüz-yüze görüşme yöntemiyle doldurulmuştur. Bulgular: Katılımcıların %99,2’si (n=125 kamu kurumlarının ücretsiz MGA sağlamasını destekliyordu ve tamamı (N=126 gelecek yıl da ücretsiz MGA temin edilmesini istiyordu. 2010 yılında yapılan ikinci ankette ücretsiz sağlanan PGA olanların oranının ise %4 (n=5 olduğu tespit edildi. Sonuç: Bağışıklama hizmetlerinden yararlanmada ekonomik faktörlerin çok önemli olduğu, ancak toplumun güven duygusunun zedelenmesinin, ücretsiz sağlansa da aşılamayı ciddi düzeyde engellediği saptanmıştır.Anahtar Kelimeler: Mevsimsel grip aşısı, pandemik grip aşısı Attitudes and behaviors related to free pandemic influenza vaccination of who gets vaccinated with free seasonal influenza vaccine  Objective: This study aims to compare attitudes and behaviors of the people who receive free Seasonal Influenza Vaccine (SIV with their attitudes and behaviors against Pandemic Influenza Vaccine (PIV which is also free, but controversial. Method: This study is a descriptive survey which was carried out within the service area of Evrensekiz Primary Healthcare Center (PHC in Kırklareli province and it was conducted between February 2009 and February 2010. The questionnaire has been applied by face to face interviews. Results: 99,2%of participants (n=125 supported providing free influenza vaccine by governmental organizations and all of them (N=126 wanted to get free influenza vaccine the next year

  11. Malzeme Taşıma Odaklı Planlama için Üretim Sistemlerindeki Tezgah Yerleşim Düzenlerinin Benzetim Analizi ile Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Mehmet AKSARAYLI

    2009-02-01

    Full Text Available Günümüzde işletmeler üretim maliyetlerini azaltmak ve verimliliklerinin artırmak için uygun tesis planları yapmak zorundadırlar. Çalışma, üretim sistemlerindeki tesis içi yerleşim problemlerinin çözümüne ulaşmakta kullanılan temel tezgâh yerleşim şekilleri ve ürüne göre yerleşim için önerilen yeni bir yaklaşımı birbirleriyle karşılaştıran bir çalışmadır. Çalışmada özellikle tezgâhlar arasındaki malzeme taşıma süreleri ve bu sürelerin toplam üretim süresi içerisindeki oranları ile ilgilenilmiştir. Buna ek olarak, incelenen tüm tezgâh yerleşim şekillerine göre benzetim modelleri sonucunda elde edilen tezgâhların kullanım yüzdeleri ve ürünlerin üretim miktarları da bu çalışma kapsamında aktarılmıştır. Çalışmada ilk olarak tesis planlamasında kullanılan temel yerleşim şekilleri için bir üretim sistemi tanımlanmıştır. Daha sonra tanımlanan üretim sistemi, her bir yerleşim şekli için tezgâh yerleşimi yapılmıştır. Ardından ürüne göre yerleşim şekli için önerilen yaklaşım aktarılarak üretim sistemi için tezgâh yerleşimi yapılmıştır. Daha sonra tezgâh yerleşim şekilleri "PROMODEL" benzetim yazılımı ortamına aktarılmıştır. Son olarak yapılan analizler ile farklı tezgâh yerleşim şekillerinin malzeme taşıma süreleri ve toplam üretim süresi içerisindeki oranları karşılaştırılmış ve analizlerden elde edilen sonuçlar yorumlanarak aktarılmıştır.

  12. Receptor Tyrosine Kinases in Drosophila Development

    Science.gov (United States)

    Sopko, Richelle; Perrimon, Norbert

    2013-01-01

    Tyrosine phosphorylation plays a significant role in a wide range of cellular processes. The Drosophila genome encodes more than 20 receptor tyrosine kinases and extensive studies in the past 20 years have illustrated their diverse roles and complex signaling mechanisms. Although some receptor tyrosine kinases have highly specific functions, others strikingly are used in rather ubiquitous manners. Receptor tyrosine kinases regulate a broad expanse of processes, ranging from cell survival and proliferation to differentiation and patterning. Remarkably, different receptor tyrosine kinases share many of the same effectors and their hierarchical organization is retained in disparate biological contexts. In this comprehensive review, we summarize what is known regarding each receptor tyrosine kinase during Drosophila development. Astonishingly, very little is known for approximately half of all Drosophila receptor tyrosine kinases. PMID:23732470

  13. Receptor binding studies of the living heart

    International Nuclear Information System (INIS)

    Syrota, A.

    1988-01-01

    Receptors form a class of intrinsic membrane proteins (or glycoproteins) defined by the high affinity and specificity with which they bind ligands. Many receptors are associated directly or indirectly with membrane ion channels that open or close after a conformational change of the receptor induced by the binding of the neurotransmitter. Changes in number and/or affinity of cardiac neurotransmitter receptors have been associated with myocardial ischemia and infarction, congestive heart failure, and cardiomyopathy as well as diabetes or thyroid-induced heart muscle disease. These alterations of cardiac receptors have been demonstrated in vitro on membrane homogenates from samples collected mainly during surgery or postmortem. The disadvantage of these in vitro binding techniques is that receptors lose their natural environment and their relationships with the other components of the tissue

  14. Subtype selective kainic acid receptor agonists

    DEFF Research Database (Denmark)

    Bunch, Lennart; Krogsgaard-Larsen, Povl

    2009-01-01

    (S)-Glutamic acid (Glu) is the major excitatory neurotransmitter in the mammalian central nervous system, activating the plethora of glutamate receptors (GluRs). In broad lines, the GluRs are divided into two major classes: the ionotropic Glu receptors (iGluRs) and the metabotropic Glu receptors (m......GluRs). Within the iGluRs, five subtypes (KA1, KA2, iGluR5-7) show high affinity and express full agonist activity upon binding of the naturally occurring amino acid kainic acid (KA). Thus these receptors have been named the KA receptors. This review describes all-to our knowledge-published KA receptor agonists...

  15. Characteristic molecular vibrations of adenosine receptor ligands.

    Science.gov (United States)

    Chee, Hyun Keun; Yang, Jin-San; Joung, Je-Gun; Zhang, Byoung-Tak; Oh, S June

    2015-02-13

    Although the regulation of membrane receptor activation is known to be crucial for molecular signal transduction, the molecular mechanism underlying receptor activation is not fully elucidated. Here we study the physicochemical nature of membrane receptor behavior by investigating the characteristic molecular vibrations of receptor ligands using computational chemistry and informatics methods. By using information gain, t-tests, and support vector machines, we have identified highly informative features of adenosine receptor (AdoR) ligand and corresponding functional amino acid residues such as Asn (6.55) of AdoR that has informative significance and is indispensable for ligand recognition of AdoRs. These findings may provide new perspectives and insights into the fundamental mechanism of class A G protein-coupled receptor activation. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  16. Acetylcholine receptors in the human retina

    International Nuclear Information System (INIS)

    Hutchins, J.B.; Hollyfield, J.G.

    1985-01-01

    Evidence for a population of acetylcholine (ACh) receptors in the human retina is presented. The authors have used the irreversible ligand 3 H-propylbenzilylcholine mustard ( 3 H-PrBCM) to label muscarinic receptors. 3 H- or 125 I-alpha-bungarotoxin (alpha-BTx) was used to label putative nicotinic receptors. Muscarinic receptors are apparently present in the inner plexiform layer of the retina. Autoradiographic grain densities are reduced in the presence of saturating concentrations of atropine, quinuclidinyl benzilate or scopolamine; this indicates that 3 H-PrBCM binding is specific for a population of muscarinic receptors in the human retina. Binding sites for radiolabeled alpha-BTx are found predominantly in the inner plexiform layer of the retina. Grain densities are reduced in the presence of d-tubocurarine, indicating that alpha-BTx may bind to a pharmacologically relevant nicotinic ACh receptor. This study provides evidence for cholinergic neurotransmission in the human retina

  17. Mermer Atıkları Kullanılarak Üretilen Otomotiv Fren Balatasının Sürtünme Katsayısının Farklı Fren Balataları İle Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Mustafa Timur

    2013-01-01

    Full Text Available Otomotiv frenlerinde kullanılan balatalar birçok maddenin bileşiminden yapılır. Bir fren balatasından istenilen temel özellikler, standartlara uygun aşınma direnci, sürtünme katsayısıdır. Frenleme sırasında sürtünme nedeniyle fren balataları aşırı ısınmaktadır. Aşırı sıcaklık nedeniyle balataların frenleme performansı değişebilmekte veya balatalar mekanik deformasyona uğramaktadır. Bu çalışmada; Türkiye'de mermerin işlenmesi neticesinde ortaya çıkan mermer toz atıklarının değerlendirilmesi amaçlanmıştır. Bu amaç için, mermer artıkları öğütülerek toz haline getirilmiştir. Çeşitli katkı maddeleri kullanılarak yeni formülasyonlu fren balataları üretilmiştir. Üretilen fren balatalarının sürtünme performansları farklı firmaların balataları ile karşılaştırılarak sonuçlar grafikler halinde gösterilmiştir. Böylece mermer tozunun frenleme performansına etkisi incelenmiştir. Mermer tozunun frenleme performansında olumlu sonuçlar verdiği gözlemlenmiştir.

  18. Veri Madenciliğinde Kümeleme Teknikleri Üzerine Bir Çalışma: K-Means ve K-Medoids Kümeleme Algoritmalarının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Güncel SARIMAN

    2014-07-01

    Full Text Available Günümüzde bilişim alanındaki gelişmeler sayesinde kullanıcılar daha gelişmiş bilgisayar teknolojilerine hakim olmaktadır ve bu gelişmeler beraberinde sayısal verilerin birikmesine neden olmaktadır. Bilişim teknolojileri biriken verileri saklayabilir. Tüm bu saklanan verilerin anlamlandırılması için veri madenciliği kullanılmaktadır. Veri madenciliği, verilerden önceden bilinmeyen anlamlı bilgileri tanımlama ya da tahmin etme tekniklerini içermektedir. Veri madenciliğinde verileri ortak özellikleri ile gruplamak için kümeleme algoritmaları yardımıyla ilginç desenler bulunabilir. Bu çalışmada UCI Machine Learning Repository veritabanından “Flags” veri seti alınarak k-means ve k-medoids bölümlemeli kümeleme algoritmalarıyla ülkelerin özelliklerine göre kümelere ayrılması hedeflenmiştir. Uygulama Asp.Net ile web ara yüzünde geliştirilerek internet ortamında kullanıcılara sunulmuştur. Çalışmanın sonunda veri seti K-Means ve K-Medoids algoritmalarıyla çalıştırılmış ve elde edilen analiz sonuçları karşılaştırılmalı olarak incelenmiş ve kullanım yerlerine yönelik öneriler sunulmuştur

  19. Studies on insulin receptor, 1

    International Nuclear Information System (INIS)

    Sakai, Yukio

    1979-01-01

    The present study was designed for the purpose of establishing a method of insulin radioreceptor assay using plasma membranes of guinea pigs as receptor sites. The results obtained are as follows: 1) Insulin receptor in the renal plasma membranes of guinea pigs showed a significantly high affinity to porcine insulin compared with that in the plasma membranes of guinea pig liver or rat kidney and liver. 2) In the insulin radioreceptor assay, an optimum condition was observed by the incubation at 4 0 C for 24 - 48 hours with 100 μg membrane protein of guinea pig kidney and 0.08 ng of 125 I-insulin. This assay method was specific for insulin and showed an accurate biological activity of insulin. 3) The recovery rate of insulin radioreceptor assay was 98.4% and dilution check up to 16 times did not influence on the result. An average of coefficient variation was 3.92% within assay. All of these results indicated the method to be satisfactory. 4) Glucose induced insulin release by perfusion method in isolated Langerhans islets of rats showed an identical pattern of reaction curves between radioreceptor assay and radioimmunoassay, although the values of radioreceptor assay was slightly low. 5) Insulin free serum produced by ultra filtration method was added to the standard assay medium. By this procedure, direct measurement of human serum by radioreceptor assay became possible. 6) The value of human serum insulin receptor binding activity by the radioreceptor assay showed a high correlation with that of insulin radioimmunoassay in sera of normal, borderline or diabetic type defined by glucose tolerance test. (author)

  20. Seventh Symposium on Subtypes of Musccarinic Receptors.

    Science.gov (United States)

    1997-01-01

    nociceptive pain, are less than ideal. For mild to moderate pain, the first line of therapy includes aspirin, acetaminophen/ paracetamol , and nonsteroidal...due to receptor degradation triggered by prolonged carbachol occupancy. This down-regulation was accompanied by uncoupling of the M2-receptors after 24...be under control by the m3 mAChR, suggesting a complex receptor regulation of phosphoinositide metabolism, including degradation and synthesis. Future

  1. Molecular identification of the first SIFamide receptor

    DEFF Research Database (Denmark)

    Jørgensen, Lars M; Hauser, Frank; Cazzamali, Giuseppe

    2006-01-01

    , an impressive sequence conservation (67-77% amino acid sequence identities between the seven-transmembrane areas; 82-87% sequence similarities). The identification of well-conserved SIFamide receptor orthologues in all other insects with a sequenced genome, suggests that the SIFamide/receptor couple must have...... an essential function in arthropods. This paper is the first report on the identification of a SIFamide receptor....

  2. Progesterone receptor modulators in breast cancer

    OpenAIRE

    WIEHLE, Ronald D.

    2015-01-01

    Breast cancer has been treated successfully with selective estrogen receptor antagonists (SERMs) such as tamoxifen, receptor-depleting agents such as fulvestrant, and aromatase inhibitors such as anastrozole. Selective progesterone receptor modulators (SPRMs or PRMs) have not been studied as much and are currently under investigation for inhibition of mammary carcinogenesis in animal models and breast cancer prevention trials in women. They might follow tamoxifen and aromatase inhibitors in t...

  3. Androgen Receptor Signaling in Bladder Cancer

    OpenAIRE

    Li, Peng; Chen, Jinbo; Miyamoto, Hiroshi

    2017-01-01

    Emerging preclinical findings have indicated that steroid hormone receptor signaling plays an important role in bladder cancer outgrowth. In particular, androgen-mediated androgen receptor signals have been shown to correlate with the promotion of tumor development and progression, which may clearly explain some sex-specific differences in bladder cancer. This review summarizes and discusses the available data, suggesting the involvement of androgens and/or the androgen receptor pathways in u...

  4. Muscarinic Receptor Agonists and Antagonists

    Directory of Open Access Journals (Sweden)

    David R. Kelly

    2001-02-01

    Full Text Available A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes. Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.

  5. Hemoglobin and heme scavenger receptors

    DEFF Research Database (Denmark)

    Nielsen, Marianne Jensby; Møller, Holger Jon; Moestrup, Søren Kragh

    2010-01-01

    Heme, the functional group of hemoglobin, myoglobin, and other hemoproteins, is a highly toxic substance when it appears in the extracellular milieu. To circumvent potential harmful effects of heme from hemoproteins released during physiological or pathological cell damage (such as hemolysis...... and rhabdomyolysis), specific high capacity scavenging systems have evolved in the mammalian organism. Two major systems, which essentially function in a similar way by means of a circulating latent plasma carrier protein that upon ligand binding is recognized by a receptor, are represented by a) the hemoglobin...

  6. Kadına Karşı Ayrımcılığın Önlenmesi Sözleşmesinin (CEDAW Müslüman Ülke Kanunlarına Etkileri / The Impact of the Convention on the Elimination of all Forms of Discrimination against Women (CEDAW on Muslim Countries Laws

    Directory of Open Access Journals (Sweden)

    İsmail Yalçın

    2017-10-01

    Full Text Available Abstract The Convention on the Elimination of All Forms of Discrimination against Women (CEDAW, which was adopted by the UN and by most countries of the world, has influenced women’s rights and led to important developments in countries party to the treaty. Most Islamic countries have put reservations on some articles of the Convention citing Islamic law practices and local culture while ratifying the Treaty, but then have removed some of these reservations by passing adaptive laws. While some of these regulations such as women’s share in inheritance, their testimony, and obedience to husband have a strong connection to main religious sources, others such as reduced sentences in honor killings, women carrying their own surname, voting in elections, and female genital mutilation are based on customary and tacit law judgments. Through CEDAW, Muslim countries have faced pressure and criticism in international platforms with the allegation that their laws on person, family, inheritance, punishments, citizenship, and procedural law involve discrimination against women. With the influence of the international atmosphere, women’s movements have risen in Muslim countries and through legal changes there has been developments with regard to women’s rights in line with CEDAW. Even though after CEDAW there is some convergence between the Islamic World and the West in terms of women’s rights and gender equality, differences based on culture continue to exist.   Öz Dünya ülkelerinin büyük çoğunluğunun taraf olduğu Birleşmiş Milletler Kadına Karşı Her Türlü Ayrımcılığın Önlenmesi Sözleşmesi (CEDAW, imzalandığı günden bu tarafa kadın hakları alanında önemli gelişmelere sebep olmuş ve taraf ülkeleri etkilemiştir. İslam ülkelerinin birçoğu, İslam hukuku uygulamalarından veya yerel kültürden kaynaklanan farlılıklar sebebiyle, katılmadığı maddelere çekince koyarak Sözleşmeyi onaylamış ancak sonradan

  7. Otizm Spektrum Bozukluğu Olan Çocuklar ve Normal Gelişim Gösteren Çocukların Statik ve Hareketli Materyallerde Yüz İşlemelerinin Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Selda Özdemir

    2017-07-01

    Full Text Available Sosyal dikkat eksikliği otizm spektrum bozukluğunun temel özelliklerinden biri olmasına rağmen, OSB’li bireylerde bu probleme neden olan faktörler yeterince anlaşılabilmiş değildir. Bu araştırmanın amacı, otizm spektrum bozukluğu olan (OSB çocukların bilgisayar ekranında kendilerine sunulan statik ve hareketli yüz ifadelerini izlerken sergiledikleri yüz işlemelerini göz izleme tekniği ile incelemek ve normal gelişim gösteren (NG çocukların yüz işleme örüntüleri ile karşılaştırmaktır. Araştırmanın katılımcıları yaşları 5 ile 12 arasında değişen OSB’li 21 çocuk ile 22 NG'li çocuktur. Araştırmada OSB’li ve NG’li çocuklara bilgisayar ekranında fotoğraf ve video izlettirilerek göz izleme verileri toplanmıştır. Araştırma kapsamında incelenen bağımlı değişken, katılımcı çocukların odaklanma sayısıdır. Araştırma kapsamında uyaran türünün (fotoğraf-video ve gelişim durumunun (OSB'li grup-NG'li grup katılımcı çocukların odaklanma sayısı üzerindeki etkileri karşılaştırılmıştır. Araştırma sonuçları bölge bazında yapılan karşılaştırmalarda OSB’li çocukların NG’li çocuklara göre alt gövde alanında daha fazla odaklandıklarını ve NG’li çocukların da ağız bölgesine OSB’li çocuklardan daha fazla odaklandıklarını göstermiştir. Statik fotoğraf ve dinamik video değişkenlerinin etkisini gösteren sonuçlar ise fotoğraf uyarını koşulunda hem OSB’li hem de NG’li çocukların daha fazla odaklanma sergilediklerini göstermiştir. Araştırma bulguları ilgili araştırmalar doğrultusunda tartışılmış ve ileri araştırmalara yönelik önerilere yer verilmiştir. Deficits in social attention is a hallmark of autism spectrum disorders (ASD, though underlying mechanisms are largely unknown. The purpose of this study was to examine face processing of children with ASD while watching a static picture and a dynamic

  8. CERAPP: Collaborative Estrogen Receptor Activity Prediction Project

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data from a large-scale modeling project called CERAPP (Collaborative Estrogen Receptor Activity Prediction Project) demonstrating using predictive computational...

  9. Identification and mechanism of ABA receptor antagonism

    KAUST Repository

    Melcher, Karsten; Xu, Yong; Ng, Ley-Moy; Zhou, X. Edward; Soon, Fen-Fen; Chinnusamy, Viswanathan; Suino-Powell, Kelly M.; Kovach, Amanda; Tham, Fook S.; Cutler, Sean R.; Li, Jun; Yong, Eu-Leong; Zhu, Jian-Kang; Xu, H. Eric

    2010-01-01

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands. © 2010 Nature America, Inc. All rights reserved.

  10. Dehydroepiandrosterone: an ancestral ligand of neurotrophin receptors.

    Science.gov (United States)

    Pediaditakis, Iosif; Iliopoulos, Ioannis; Theologidis, Ioannis; Delivanoglou, Nickoleta; Margioris, Andrew N; Charalampopoulos, Ioannis; Gravanis, Achille

    2015-01-01

    Dehydroepiandosterone (DHEA), the most abundant steroid in humans, affects multiple cellular functions of the endocrine, immune, and nervous systems. However, up to quite recently, no receptor has been described specifically for it, whereas most of its physiological actions have been attributed to its conversion to either androgens or estrogens. DHEA interacts and modulate a variety of membrane and intracellular neurotransmitter and steroid receptors. We have recently reported that DHEA protects neuronal cells against apoptosis, interacting with TrkA, the high-affinity prosurvival receptor of the neurotrophin, nerve growth factor. Intrigued by its pleiotropic effects in the nervous system of a variety of species, we have investigated the ability of DHEA to interact with the other two mammalian neurotrophin receptors, ie, the TrkB and TrkC, as well as their invertebrate counterparts (orthologs) in mollusks Lymnaea and Aplysia and in cephalochordate fish Amphioxus. Amazingly, DHEA binds to all Trk receptors, although with lower affinity by 2 orders of magnitude compared with that of the polypeptidic neurotrophins. DHEA effectively induced the first step of the TrkA and TrkC receptors activation (phosphorylation at tyrosine residues), including the vertebrate neurotrophin nonresponding invertebrate Lymnaea and Aplysia receptors. Based on our data, we hypothesize that early in evolution, DHEA may have acted as a nonspecific neurotrophic factor promoting neuronal survival. The interaction of DHEA with all types of neurotrophin receptors offers new insights into the largely unidentified mechanisms of its actions on multiple tissues and organs known to express neurotrophin receptors.

  11. Characterization of the chicken muscle insulin receptor

    International Nuclear Information System (INIS)

    Adamo, M.; Simon, J.; Rosebrough, R.W.; McMurtry, J.P.; Steele, N.C.; LeRoith, D.

    1987-01-01

    Insulin receptors are present in chicken skeletal muscle. Crude membrane preparations demonstrated specific 125 I-insulin binding. The nonspecific binding was high (36-55% of total binding) and slightly lower affinity receptors were found than are typically observed for crude membrane insulin binding in other chicken tissues. Affinity crosslinking of 125 I-insulin to crude membranes revealed insulin receptor alpha-subunits of Mr 128K, intermediate between those of liver (134K) and brain (124K). When solubilized and partially purified on wheat germ agglutinin (WGA) affinity columns, chicken muscle insulin receptors exhibited typical high affinity binding, with approximately 10(-10) M unlabeled insulin producing 50% inhibition of the specific 125 I-insulin binding. WGA purified chicken muscle insulin receptors also exhibited insulin-stimulated autophosphorylation of the beta-subunit, which appeared as phosphorylated bands of 92- and 81K. Both bands were immunoprecipitated by anti-receptor antiserum (B10). WGA purified membranes also demonstrated dose-dependent insulin-stimulated phosphorylation of the exogenous substrate poly(Glu,Tyr)4:1. However, unlike chicken liver, chicken muscle insulin receptor number and tyrosine kinase activity were unaltered by 48 hr of fasting or 48 hr of fasting and 24 hr of refeeding. Thus, despite the presence of insulin receptors in chicken muscle showing normal coupling to receptor tyrosine kinase activity, nutritional alterations modulate these parameters in a tissue-specific manner in chickens

  12. Human dopamine receptor and its uses

    Energy Technology Data Exchange (ETDEWEB)

    Civelli, Olivier (Portland, OR); Van Tol, Hubert Henri-Marie (Toronto, CA)

    1999-01-01

    The present invention is directed toward the isolation, characterization and pharmacological use of the human D4 dopamine receptor. The nucleotide sequence of the gene corresponding to this receptor and alleleic variant thereof are provided by the invention. The invention also includes recombinant eukaryotic expression constructs capable of expressing the human D4 dopamine receptor in cultures of transformed eukaryotic cells. The invention provides cultures of transformed eukaryotic cells which synthesize the human D4 dopamine receptor, and methods for characterizing novel psychotropic compounds using such cultures.

  13. Chapter 8. Activation mechanisms of chemokine receptors

    DEFF Research Database (Denmark)

    Jensen, Pia C; Rosenkilde, Mette M

    2009-01-01

    binding. Attempts to unravel the activation mechanism of 7TM receptors have led to the conclusion that activation involves movements of the transmembrane segments VI and VII in particular, as recently gathered in the Global Toggle Switch Model. However, to understand the activation mechanism completely......, more research has to be done in this field. Chemokine receptors are interesting tools in this matter. First, the chemokine system has a high degree of promiscuity that allows several chemokines to target one receptor in different ways, as well as a single chemokine ligand to target several receptors...

  14. Identification and mechanism of ABA receptor antagonism

    KAUST Repository

    Melcher, Karsten

    2010-08-22

    The phytohormone abscisic acid (ABA) functions through a family of fourteen PYR/PYL receptors, which were identified by resistance to pyrabactin, a synthetic inhibitor of seed germination. ABA activates these receptors to inhibit type 2C protein phosphatases, such as ABI1, yet it remains unclear whether these receptors can be antagonized. Here we demonstrate that pyrabactin is an agonist of PYR1 and PYL1 but is unexpectedly an antagonist of PYL2. Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition, which enables us to design mutations that convert PYL1 to a pyrabactin-inhibited receptor and PYL2 to a pyrabactin-activated receptor and to identify new pyrabactin-based ABA receptor agonists. Together, our results establish a new concept of ABA receptor antagonism, illustrate its underlying mechanisms and provide a rational framework for discovering novel ABA receptor ligands. © 2010 Nature America, Inc. All rights reserved.

  15. Knock-In Mice with NOP-eGFP Receptors Identify Receptor Cellular and Regional Localization.

    Science.gov (United States)

    Ozawa, Akihiko; Brunori, Gloria; Mercatelli, Daniela; Wu, Jinhua; Cippitelli, Andrea; Zou, Bende; Xie, Xinmin Simon; Williams, Melissa; Zaveri, Nurulain T; Low, Sarah; Scherrer, Grégory; Kieffer, Brigitte L; Toll, Lawrence

    2015-08-19

    The nociceptin/orphanin FQ (NOP) receptor, the fourth member of the opioid receptor family, is involved in many processes common to the opioid receptors including pain and drug abuse. To better characterize receptor location and trafficking, knock-in mice were created by inserting the gene encoding enhanced green fluorescent protein (eGFP) into the NOP receptor gene (Oprl1) and producing mice expressing a functional NOP-eGFP C-terminal fusion in place of the native NOP receptor. The NOP-eGFP receptor was present in brain of homozygous knock-in animals in concentrations somewhat higher than in wild-type mice and was functional when tested for stimulation of [(35)S]GTPγS binding in vitro and in patch-clamp electrophysiology in dorsal root ganglia (DRG) neurons and hippocampal slices. Inhibition of morphine analgesia was equivalent when tested in knock-in and wild-type mice. Imaging revealed detailed neuroanatomy in brain, spinal cord, and DRG and was generally consistent with in vitro autoradiographic imaging of receptor location. Multicolor immunohistochemistry identified cells coexpressing various spinal cord and DRG cellular markers, as well as coexpression with μ-opioid receptors in DRG and brain regions. Both in tissue slices and primary cultures, the NOP-eGFP receptors appear throughout the cell body and in processes. These knock-in mice have NOP receptors that function both in vitro and in vivo and appear to be an exceptional tool to study receptor neuroanatomy and correlate with NOP receptor function. The NOP receptor, the fourth member of the opioid receptor family, is involved in pain, drug abuse, and a number of other CNS processes. The regional and cellular distribution has been difficult to determine due to lack of validated antibodies for immunohistochemical analysis. To provide a new tool for the investigation of receptor localization, we have produced knock-in mice with a fluorescent-tagged NOP receptor in place of the native NOP receptor. These

  16. G-protein-coupled receptors for free fatty acids

    DEFF Research Database (Denmark)

    Milligan, Graeme; Ulven, Trond; Murdoch, Hannah

    2014-01-01

    of these receptors. However, ongoing clinical trials of agonists of free fatty acid receptor 1 suggest that this receptor and other receptors for free fatty acids may provide a successful strategy for controlling hyperglycaemia and providing novel approaches to treat diabetes. Receptors responsive to free fatty acid...

  17. Evidence for Heterodimerization and Functional Interaction of the Angiotensin Type 2 Receptor and the Receptor MAS

    DEFF Research Database (Denmark)

    Leonhardt, Julia; Villela, Daniel C.; Teichmann, Anke

    2017-01-01

    The angiotensin type 2 receptor (AT2R) and the receptor MAS are receptors of the protective arm of the renin-angiotensin system. They mediate strikingly similar actions. Moreover, in various studies, AT2R antagonists blocked the effects of MAS agonists and vice versa. Such cross-inhibition may in...

  18. Interaction of epidermal growth factor receptors with the cytoskeleton is related to receptor clustering

    NARCIS (Netherlands)

    van Belzen, N.; Spaargaren, M.; Verkleij, A. J.; Boonstra, J.

    1990-01-01

    Recently it has been established that cytoskeleton-associated epidermal growth factor (EGF) receptors are predominantly of the high-affinity class and that EGF induces a recruitment of low-affinity receptors to the cytoskeleton. The nature of this EGF-induced receptor-cytoskeleton interaction,

  19. Receptor saturation in roentgen films

    Energy Technology Data Exchange (ETDEWEB)

    Strid, K G; Reichmann, S [Sahlgrenska Sjukhuset, Goeteborg (Sweden)

    1980-01-01

    Roentgen-film recording of small object details of low attenuation differences (e.g. pulmonary vessels) is regularly seen to be impaired when the film is exposed to yield high values of optical density (D). This high-density failure is due to receptor saturation, which implies that at high exposure values most silver halide grains of the film are made developable, leaving few grains available to receive additional informative photons. The receptor saturation is analysed by means of a mathematical model of a non-screen film yielding Dsub(max) = 2.0. Optimum recording, defined by maximum signal-to-noise ratio in the image, is found at D approximately 0.64, corresponding to, on an average, 1.6 photons absorbed per grain. On the other hand, maximum contrast occurs at D approximately 1.4, where, on the average, 3.6 photons are absorbed per grain. The detective quantum efficiency of the film, i.e. the fraction of the photons actually contributing to the information content of the image, drops from 41 per cent at maximum signal-to-noise ratio to a mere 10 per cent at maximum contrast.

  20. Androgen receptor drives cellular senescence.

    Directory of Open Access Journals (Sweden)

    Yelena Mirochnik

    Full Text Available The accepted androgen receptor (AR role is to promote proliferation and survival of prostate epithelium and thus prostate cancer progression. While growth-inhibitory, tumor-suppressive AR effects have also been documented, the underlying mechanisms are poorly understood. Here, we for the first time link AR anti-cancer action with cell senescence in vitro and in vivo. First, AR-driven senescence was p53-independent. Instead, AR induced p21, which subsequently reduced ΔN isoform of p63. Second, AR activation increased reactive oxygen species (ROS and thereby suppressed Rb phosphorylation. Both pathways were critical for senescence as was proven by p21 and Rb knock-down and by quenching ROS with N-Acetyl cysteine and p63 silencing also mimicked AR-induced senescence. The two pathways engaged in a cross-talk, likely via PML tumor suppressor, whose localization to senescence-associated chromatin foci was increased by AR activation. All these pathways contributed to growth arrest, which resolved in senescence due to concomitant lack of p53 and high mTOR activity. This is the first demonstration of senescence response caused by a nuclear hormone receptor.

  1. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  2. Posttransplant chimeric antigen receptor therapy.

    Science.gov (United States)

    Smith, Melody; Zakrzewski, Johannes; James, Scott; Sadelain, Michel

    2018-03-08

    Therapeutic T-cell engineering is emerging as a powerful approach to treat refractory hematological malignancies. Its most successful embodiment to date is based on the use of second-generation chimeric antigen receptors (CARs) targeting CD19, a cell surface molecule found in most B-cell leukemias and lymphomas. Remarkable complete remissions have been obtained with autologous T cells expressing CD19 CARs in patients with relapsed, chemo-refractory B-cell acute lymphoblastic leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. Allogeneic CAR T cells may also be harnessed to treat relapse after allogeneic hematopoietic stem cell transplantation. However, the use of donor T cells poses unique challenges owing to potential alloreactivity. We review different approaches to mitigate the risk of causing or aggravating graft-versus-host disease (GVHD), including CAR therapies based on donor leukocyte infusion, virus-specific T cells, T-cell receptor-deficient T cells, lymphoid progenitor cells, and regulatory T cells. Advances in CAR design, T-cell selection and gene editing are poised to enable the safe use of allogeneic CAR T cells without incurring GVHD. © 2018 by The American Society of Hematology.

  3. Microarray-Based Determination of Estrogen Receptor, Progesterone Receptor, and HER2 Receptor Status in Breast Cancer

    NARCIS (Netherlands)

    Roepman, Paul; Horlings, Hugo M.; Krijgsman, Oscar; Kok, Marleen; Bueno-de-Mesquita, Jolien M.; Bender, Richard; Linn, Sabine C.; Glas, Annuska M.; van de Vijver, Marc J.

    2009-01-01

    Purpose: The level of estrogen receptor (ER), progesterone receptor (PR), and HER2 aids in the determination of prognosis and treatment of breast cancer. Immunohistochemistry is currently the predominant method for assessment, but differences in methods and interpretation can substantially affect

  4. Identifying the receptor subtype selectivity of retinoid X and retinoic acid receptors via quantum mechanics.

    Science.gov (United States)

    Tsuji, Motonori; Shudo, Koichi; Kagechika, Hiroyuki

    2017-03-01

    Understanding and identifying the receptor subtype selectivity of a ligand is an important issue in the field of drug discovery. Using a combination of classical molecular mechanics and quantum mechanical calculations, this report assesses the receptor subtype selectivity for the human retinoid X receptor (hRXR) and retinoic acid receptor (hRAR) ligand-binding domains (LBDs) complexed with retinoid ligands. The calculated energies show good correlation with the experimentally reported binding affinities. The technique proposed here is a promising method as it reveals the origin of the receptor subtype selectivity of selective ligands.

  5. Excitatory amino acid receptors and disease.

    Science.gov (United States)

    Meldrum, B S

    1992-08-01

    Recent advances in the molecular biology of excitatory amino acid receptors are reviewed. Evidence that drugs blocking the excitatory action of glutamate at the N-methyl-D-aspartate (NMDA) and non-NMDA receptors may be of clinical use in epilepsy, Parkinson's disease, cerebral ischaemia and trauma, acquired immune deficiency syndrome (AIDS) encephalopathy and neuropathic pain is summarized.

  6. Docking to flexible nicotinic acetylcholine receptors

    DEFF Research Database (Denmark)

    Sander, Tommy; Bruun, Anne T; Balle, Thomas

    2010-01-01

    Computational docking to nicotinic acetylcholine receptors (nAChRs) and other members of the Cys-loop receptor family is complicated by the flexibility of the so-called C-loop. As observed in the large number of published crystal structures of the acetylcholine binding protein (AChBP), a structural...

  7. Structural Studies of Nicotinic Acetylcholine Receptors

    DEFF Research Database (Denmark)

    Shahsavar, Azadeh; Gajhede, Michael; Kastrup, Jette

    2016-01-01

    Nicotinic acetylcholine receptors (nAChRs) are members of the pentameric ligand-gated ion channel superfamily that play important roles in control of neurotransmitter release in the central and peripheral nervous system. These receptors are important therapeutic targets for development of drugs...

  8. In vivo studies of opiate receptors

    International Nuclear Information System (INIS)

    Frost, J.J.; Dannals, R.F.; Duelfer, T.; Burns, H.D.; Ravert, H.T.; Langstroem, B.; Balasubramanian, V.; Wagner, H.N. Jr.

    1984-01-01

    To study opiate receptors noninvasively in vivo using positron emission tomography, techniques for preferentially labeling opiate receptors in vivo can be used. The rate at which receptor-bound ligand clears from the brain in vivo can be predicted by measuring the equilibrium dissociation constant (KD) at 37 degrees C in the presence of 100 mM sodium chloride and 100 microM guanyl-5'-imidodiphosphate, the drug distribution coefficient, and the molecular weight. A suitable ligand for labeling opiate receptors in vivo is diprenorphine, which binds to mu, delta, and kappa receptors with approximately equal affinity in vitro. However, in vivo diprenorphine may bind predominantly to one opiate receptor subtype, possibly the mu receptor. To predict the affinity for binding to the opiate receptor, a Hansch correlation was determined between the 50% inhibitory concentration for a series of halogen-substituted fentanyl analogs and electronic, lipophilic, and steric parameters. Radiochemical methods for the synthesis of carbon-11-labeled diprenorphine and lofentanil are presented

  9. In vivo studies of opiate receptors

    Energy Technology Data Exchange (ETDEWEB)

    Frost, J.J.; Dannals, R.F.; Duelfer, T.; Burns, H.D.; Ravert, H.T.; Langstroem, B.; Balasubramanian, V.; Wagner, H.N. Jr.

    1984-01-01

    To study opiate receptors noninvasively in vivo using positron emission tomography, techniques for preferentially labeling opiate receptors in vivo can be used. The rate at which receptor-bound ligand clears from the brain in vivo can be predicted by measuring the equilibrium dissociation constant (KD) at 37 degrees C in the presence of 100 mM sodium chloride and 100 microM guanyl-5'-imidodiphosphate, the drug distribution coefficient, and the molecular weight. A suitable ligand for labeling opiate receptors in vivo is diprenorphine, which binds to mu, delta, and kappa receptors with approximately equal affinity in vitro. However, in vivo diprenorphine may bind predominantly to one opiate receptor subtype, possibly the mu receptor. To predict the affinity for binding to the opiate receptor, a Hansch correlation was determined between the 50% inhibitory concentration for a series of halogen-substituted fentanyl analogs and electronic, lipophilic, and steric parameters. Radiochemical methods for the synthesis of carbon-11-labeled diprenorphine and lofentanil are presented.

  10. Receptor study of psychiatric disorders using PET

    International Nuclear Information System (INIS)

    Suhara, Tetsuya

    1992-01-01

    Recent receptor studies of psychiatric disorders using PET have been focused on the change in the number of D 2 dopamine receptors in the striatum of drug-naive schizophrenic patients. One study confirmed an increase in D 2 receptors, while another study denied it. Although there were some differences in the approaches of the two groups, the reason for the discrepancy is not clear yet. Looking to psychiatric disorders other than schizophrenia, our recent study revealed a possible role of dopamine D 1 receptors in bipolar mood disorders. However, some problems must be resolved for further receptor studies with PET. For example, our recent study shows that desipamine decreases the in vivo binding of dopramine D 1 and D 2 receptors whereas these is no effect on dopamine D 1 and D 2 receptors in vitro. Additionally significant methodological problems lie in the method of evaluation of the non-specific binding and the effect of endogenous neurotransmitters. Moreover, difficulties in the diagnosis of psychiatric disorders and ethical problems in psychiatric research are critical factors in receptor studies with PET in psychiatric disorders. (author)

  11. P2X receptors in epithelia

    DEFF Research Database (Denmark)

    Leipziger, Jens Georg

    2015-01-01

    P2X receptors are ubiquitously expressed in all epithelial tissues but their functional roles are less well studied. Here we review the current state of knowledge by focusing on functional effects of P2X receptor in secretory and in absorptive tissues. In glandular tissue like the parotid gland...

  12. Structural Mapping of Adenosine Receptor Mutations

    DEFF Research Database (Denmark)

    Jespers, Willem; Schiedel, Anke C; Heitman, Laura H

    2018-01-01

    The four adenosine receptors (ARs), A1, A2A, A2B, and A3, constitute a subfamily of G protein-coupled receptors (GPCRs) with exceptional foundations for structure-based ligand design. The vast amount of mutagenesis data, accumulated in the literature since the 1990s, has been recently supplemente...

  13. Emerging functions for neuropeptide Y5 receptors

    NARCIS (Netherlands)

    Bischoff, A.; Michel, M. C.

    1999-01-01

    The Y5 subtype of neuropeptide Y (NPY) receptors has raised considerable interest as a mediator of NPY-stimulated food intake, but with the advent of recent data, this hypothesis has come into question. Moreover, Y5 receptor-selective drugs might not be specific for food intake because additional

  14. Immunohistochemical assessment of oestrogen and progesterone receptors

    DEFF Research Database (Denmark)

    Grabau, D A; Thorpe, S M; Knoop, A

    2000-01-01

    Two different methods to determine steroid receptors were analysed with respect to their ability to estimate prognosis in primary breast cancer patients. The immunohistochemical assay (IHA) was compared with the dextran-coated charcoal (DCC) method of receptor determination. A random sample of 28...... distinction between benign and malignant tissue is possible using the IHAmethod. Thus, IHAresults appear to be more clinically relevant....

  15. Lipoprotein receptors in cultured bovine endothelial cells

    International Nuclear Information System (INIS)

    Struempfer, A.E.M.

    1983-07-01

    In this study, receptors that may be involved in the uptake of low density lipoproteins (LDL) and low density lipoproteins which have been modified by acetylation (AcLDL), were characterized. Aortic epithelial cells were used and a cell culture system which closely resembled the in vivo monolayer was established. Endothelial cell and lipoprotein interactions were examined by incubating the cells with 125 l-labelled lipoproteins under various conditions. The receptor affinity of bovine aortic endothelial cells was higher for AcLDL than that for LDL. Competition studies demonstrated that there were two distinct receptors for LDL and AcLDL on the endothelial cells. AcLDL did not compete with LDL for the LDL receptor, and conversely LDL did not compete with AcLDL for the AcLDL receptor. The receptor activities for LDL and AcLDL were examined as a function of culture age. Whereas the LDL receptor could be regulated, the AcLDL receptor was not as susceptible to regulation. Upon exposing endothelial cells for 72 h to either LDL or AcLDL, it was found that the total amount of cellular cholesterol increased by about 50%. However, the increase of total cholesterol was largely in the form of free cholesterol. This is in contrast to macrophages, where the increase in total cholesterol upon exposure to AcLDL is largely in the form cholesteryl esters

  16. Thermogenic characterization of ghrelin receptor null mice

    Science.gov (United States)

    Ghrelin is the only known circulating orexigenic hormone that increases food intake and promotes adiposity, and these physiological functions of ghrelin are mediated through its receptor growth hormone secretagogue receptor (GHS-R). Ghrelin/GHS-R signaling plays a crucial role in energy homeostasis....

  17. Complex Pharmacology of Free Fatty Acid Receptors

    DEFF Research Database (Denmark)

    Milligan, Graeme; Shimpukade, Bharat; Ulven, Trond

    2017-01-01

    pharmacology have shaped understanding of the complex pharmacology of receptors that recognize and are activated by nonesterified or "free" fatty acids (FFAs). The FFA family of receptors is a recently deorphanized set of GPCRs, the members of which are now receiving substantial interest as novel targets...

  18. Neutral anion receptors: design and application

    NARCIS (Netherlands)

    Antonisse, M.M.G.; Reinhoudt, David

    1998-01-01

    After the development of synthetic cation receptors in the late 1960s, only in the past decade has work started on the development of synthetic neutral anion receptors. Combination and preorganization of different anion binding groups, like amides, urea moieties, or Lewis acidic metal centers lead

  19. NRSAS: Nuclear Receptor Structure Analysis Servers.

    NARCIS (Netherlands)

    Bettler, E.J.M.; Krause, R.; Horn, F.; Vriend, G.

    2003-01-01

    We present a coherent series of servers that can perform a large number of structure analyses on nuclear hormone receptors. These servers are part of the NucleaRDB project, which provides a powerful information system for nuclear hormone receptors. The computations performed by the servers include

  20. Transient receptor potential channels in essential hypertension

    DEFF Research Database (Denmark)

    Liu, Daoyan; Scholze, Alexandra; Zhu, Zhiming

    2006-01-01

    The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated.......The role of nonselective cation channels of the transient receptor potential channel (TRPC) family in essential hypertension has not yet been investigated....