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Sample records for ca3 ca1 subiculum

  1. Synaptic Remodeling in the Dentate Gyrus, CA3, CA1, Subiculum, and Entorhinal Cortex of Mice: Effects of Deprived Rearing and Voluntary Running

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    Andrea T. U. Schaefers

    2010-01-01

    Full Text Available Hippocampal cell proliferation is strongly increased and synaptic turnover decreased after rearing under social and physical deprivation in gerbils (Meriones unguiculatus. We examined if a similar epigenetic effect of rearing environment on adult neuroplastic responses can be found in mice (Mus musculus. We examined synaptic turnover rates in the dentate gyrus, CA3, CA1, subiculum, and entorhinal cortex. No direct effects of deprived rearing on rates of synaptic turnover were found in any of the studied regions. However, adult wheel running had the effect of leveling layer-specific differences in synaptic remodeling in the dentate gyrus, CA3, and CA1, but not in the entorhinal cortex and subiculum of animals of both rearing treatments. Epigenetic effects during juvenile development affected adult neural plasticity in mice, but seemed to be less pronounced than in gerbils.

  2. Electrophysiological and Morphological Characterization of Chrna2 Cells in the Subiculum and CA1 of the Hippocampus: An Optogenetic Investigation

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    Heather Nichol

    2018-02-01

    Full Text Available The nicotinic acetylcholine receptor alpha2 subunit (Chrna2 is a specific marker for oriens lacunosum-moleculare (OLM interneurons in the dorsal CA1 region of the hippocampus. It was recently shown using a Chrna2-cre mice line that OLM interneurons can modulate entorhinal cortex and CA3 inputs and may therefore have an important role in gating, encoding, and recall of memory. In this study, we have used a combination of electrophysiology and optogenetics using Chrna2-cre mice to determine the role of Chrna2 interneurons in the subiculum area, the main output region of the hippocampus. We aimed to assess the similarities between Chrna2 subiculum and CA1 neurons in terms of the expression of interneuron markers, their membrane properties, and their inhibitory input to pyramidal neurons. We found that subiculum and CA1 dorsal Chrna2 cells similarly expressed the marker somatostatin and had comparable membrane and firing properties. The somas of Chrna2 cells in both regions were found in the deepest layer with axons projecting superficially. However, subiculum Chrna2 cells displayed more extensive projections with dendrites which occupied a significantly larger area than in CA1. The post-synaptic responses elicited by Chrna2 cells in pyramidal cells of both regions revealed comparable inhibitory responses elicited by GABAA receptors and, interestingly, GABAB receptor mediated components. This study provides the first in-depth characterization of Chrna2 cells in the subiculum, and suggests that subiculum and CA1 Chrna2 cells are generally similar and may play comparable roles in both sub-regions.

  3. Synaptic plasticity in the hippocampal area CA1-subiculum projection: implications for theories of memory.

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    O'Mara, S M; Commins, S; Anderson, M

    2000-01-01

    This paper reviews investigations of synaptic plasticity in the major, and underexplored, pathway from hippocampal area CA1 to the subiculum. This brain area is the major synaptic relay for the majority of hippocampal area CA1 neurons, making the subiculum the last relay of the hippocampal formation prior to the cortex. The subiculum thus has a very major role in mediating hippocampal-cortical interactions. We demonstrate that the projection from hippocampal area CA1 to the subiculum sustains plasticity on a number of levels. We show that this pathway is capable of undergoing both long-term potentiation (LTP) and paired-pulse facilitation (PPF, a short-term plastic effect). Although we failed to induce long-term depression (LTD) of this pathway with low-frequency stimulation (LFS) and two-pulse stimulation (TPS), both protocols can induce a "late-developing" potentiation of synaptic transmission. We further demonstrate that baseline synaptic transmission can be dissociated from paired-pulse stimulation of the same pathway; we also show that it is possible, using appropriate protocols, to change PPF to paired-pulse depression, thus revealing subtle and previously undescribed mechanisms which regulate short-term synaptic plasticity. Finally, we successfully recorded from individual subicular units in the freely-moving animal, and provide a description of the characteristics of such neurons in a pellet-chasing task. We discuss the implications of these findings in relation to theories of the biological consolidation of memory.

  4. Memory Dysfunction in Type 2 Diabetes Mellitus Correlates with Reduced Hippocampal CA1 and Subiculum Volumes

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    Yan-Wei Zhang

    2015-01-01

    Full Text Available Background: Little attention has been paid to the role of subcortical deep gray matter (SDGM structures in type 2 diabetes mellitus (T2DM-induced cognitive impairment, especially hippocampal subfields. Our aims were to assess the in vivo volumes of SDGM structures and hippocampal subfields using magnetic resonance imaging (MRI and to test their associations with cognitive performance in T2DM. Methods: A total of 80 T2DM patients and 80 neurologically unimpaired healthy controls matched by age, sex and education level was enrolled in this study. We assessed the volumes of the SDGM structures and seven hippocampal subfields on MRI using a novel technique that enabled automated volumetry. We used Mini-Mental State Examination and Montreal Cognitive Assessment (MoCA scores as measures of cognitive performance. The association of glycosylated hemoglobin (HbA1c with SDGM structures and neuropsychological tests and correlations between hippocampal subfields and neuropsychological tests were assessed by partial correlation analysis in T2DM. Results: Bilaterally, the hippocampal volumes were smaller in T2DM patients, mainly in the CA1 and subiculum subfields. Partial correlation analysis showed that the MoCA scores, particularly those regarding delayed memory, were significantly positively correlated with reduced hippocampal CA1 and subiculum volumes in T2DM patients. Additionally, higher HbA1c levels were significantly associated with poor memory performance and hippocampal atrophy among T2DM patients. Conclusions: These data indicate that the hippocampus might be the main affected region among the SDGM structures in T2DM. These structural changes in the hippocampal CA1 and subiculum areas might be at the core of underlying neurobiological mechanisms of hippocampal dysfunction, suggesting that degeneration in these regions could be responsible for memory impairments in T2DM patients.

  5. Cell-Type-Specific Circuit Connectivity of Hippocampal CA1 Revealed through Cre-Dependent Rabies Tracing

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    Yanjun Sun

    2014-04-01

    Full Text Available We developed and applied a Cre-dependent, genetically modified rabies-based tracing system to map direct synaptic connections to specific CA1 neuron types in the mouse hippocampus. We found common inputs to excitatory and inhibitory CA1 neurons from CA3, CA2, the entorhinal cortex (EC, the medial septum (MS, and, unexpectedly, the subiculum. Excitatory CA1 neurons receive inputs from both cholinergic and GABAergic MS neurons, whereas inhibitory neurons receive a great majority of inputs from GABAergic MS neurons. Both cell types also receive weaker input from glutamatergic MS neurons. Comparisons of inputs to CA1 PV+ interneurons versus SOM+ interneurons showed similar strengths of input from the subiculum, but PV+ interneurons received much stronger input than SOM+ neurons from CA3, the EC, and the MS. Thus, rabies tracing identifies hippocampal circuit connections and maps how the different input sources to CA1 are distributed with different strengths on each of its constituent cell types.

  6. Preictal activity of subicular, CA1, and dentate gyrus principal neurons in the dorsal hippocampus before spontaneous seizures in a rat model of temporal lobe epilepsy.

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    Fujita, Satoshi; Toyoda, Izumi; Thamattoor, Ajoy K; Buckmaster, Paul S

    2014-12-10

    Previous studies suggest that spontaneous seizures in patients with temporal lobe epilepsy might be preceded by increased action potential firing of hippocampal neurons. Preictal activity is potentially important because it might provide new opportunities for predicting when a seizure is about to occur and insight into how spontaneous seizures are generated. We evaluated local field potentials and unit activity of single, putative excitatory neurons in the subiculum, CA1, CA3, and dentate gyrus of the dorsal hippocampus in epileptic pilocarpine-treated rats as they experienced spontaneous seizures. Average action potential firing rates of neurons in the subiculum, CA1, and dentate gyrus, but not CA3, increased significantly and progressively beginning 2-4 min before locally recorded spontaneous seizures. In the subiculum, CA1, and dentate gyrus, but not CA3, 41-57% of neurons displayed increased preictal activity with significant consistency across multiple seizures. Much of the increased preictal firing of neurons in the subiculum and CA1 correlated with preictal theta activity, whereas preictal firing of neurons in the dentate gyrus was independent of theta. In addition, some CA1 and dentate gyrus neurons displayed reduced firing rates preictally. These results reveal that different hippocampal subregions exhibit differences in the extent and potential underlying mechanisms of preictal activity. The finding of robust and significantly consistent preictal activity of subicular, CA1, and dentate neurons in the dorsal hippocampus, despite the likelihood that many seizures initiated in other brain regions, suggests the existence of a broader neuronal network whose activity changes minutes before spontaneous seizures initiate. Copyright © 2014 the authors 0270-6474/14/3416671-17$15.00/0.

  7. Focal CA3 hippocampal subfield atrophy following LGI1 VGKC-complex antibody limbic encephalitis.

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    Miller, Thomas D; Chong, Trevor T-J; Aimola Davies, Anne M; Ng, Tammy W C; Johnson, Michael R; Irani, Sarosh R; Vincent, Angela; Husain, Masud; Jacob, Saiju; Maddison, Paul; Kennard, Christopher; Gowland, Penny A; Rosenthal, Clive R

    2017-05-01

    Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0.39 × 1.0 mm3) 7.0 T magnetic resonance imaging [n = 18 patients, 17 patients (94%) positive for LGI1 antibody and one patient negative for LGI1/CASPR2 but positive for VGKC-complex antibodies, mean age: 64.0 ± 2.55 years, median 4 years post-limbic encephalitis onset; n = 18 controls]. First, hippocampal subfield quantitative morphometry indicated significant volume loss confined to bilateral CA3 [F(1,34) = 16.87, P 3 months from symptom onset) were associated with CA3 atrophy. Third, whole-brain voxel-by-voxel morphometry revealed no significant grey matter loss. Fourth, CA3 subfield atrophy was associated with severe episodic but not semantic amnesia for postmorbid autobiographical events that was predicted by variability in CA3 volume. The results raise important questions about the links with histopathology, the impact of the observed focal atrophy on other CA3-mediated reconstructive and episodic mechanisms, and the role of potential antibody-mediated pathogenicity as part of the pathophysiology cascade in humans. © The Author (2017). Published by Oxford University Press on behalf of the Guarantors of Brain.

  8. CaV 3.1 and CaV 3.3 account for T-type Ca2+ current in GH3 cells

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    M.A. Mudado

    2004-06-01

    Full Text Available T-type Ca2+ channels are important for cell signaling by a variety of cells. We report here the electrophysiological and molecular characteristics of the whole-cell Ca2+ current in GH3 clonal pituitary cells. The current inactivation at 0 mV was described by a single exponential function with a time constant of 18.32 ± 1.87 ms (N = 16. The I-V relationship measured with Ca2+ as a charge carrier was shifted to the left when we applied a conditioning pre-pulse of up to -120 mV, indicating that a low voltage-activated current may be present in GH3 cells. Transient currents were first activated at -50 mV and peaked around -20 mV. The half-maximal voltage activation and the slope factors for the two conditions are -35.02 ± 2.4 and 6.7 ± 0.3 mV (pre-pulse of -120 mV, N = 15, and -27.0 ± 0.97 and 7.5 ± 0.7 mV (pre-pulse of -40 mV, N = 9. The 8-mV shift in the activation mid-point was statistically significant (P < 0.05. The tail currents decayed bi-exponentially suggesting two different T-type Ca2+ channel populations. RT-PCR revealed the presence of a1G (CaV3.1 and a1I (CaV3.3 T-type Ca2+ channel mRNA transcripts.

  9. Resilience to audiogenic seizures is associated with p-ERK1/2 dephosphorylation in the subiculum of Fmr1 knockout mice

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    Giulia eCuria

    2013-04-01

    Full Text Available Young, but not adult, Fmr1 knockout (KO mice display audiogenic seizures (AGS that can be prevented by inhibiting extracellular signal-regulated kinases 1/2 (ERK1/2 phosphorylation. In order to identify the cerebral regions involved in these phenomena, we characterized the response to AGS in Fmr1 KO mice and wild type (WT controls at postnatal day (P 45 and P90. To characterize the diverse response to AGS in various cerebral regions, we evaluated the activity markers FosB/ΔFosB and phosphorylated ERK1/2 (p-ERK1/2. Wild running (100% of tested mice followed by clonic/tonic seizures (30% were observed in P45 Fmr1 KO mice, but not in WT mice. In P90 Fmr1 KO mice, wild running was only present in 25% of tested animals. Basal FosB/ΔFosB immunoreactivity was higher (P<0.01 vs WT in the CA1 and subiculum of P45 Fmr1 KO mice. Following the AGS test, FosB/ΔFosB expression consistently increased in most of the analyzed regions in both groups at P45, but not at P90. Interestingly, FosB/ΔFosB immunoreactivity was significantly higher in P45 Fmr1 KO mice in the medial geniculate body (P<0.05 vs WT and CA3 (P<0.01. Neurons presenting with immunopositivity to p-ERK1/2 were more abundant in the subiculum of Fmr1 KO mice in control condition (P<0.05 vs WT, in both age groups. In this region, p-ERK1/2-immunopositive cells significantly decreased (-75%, P<0.01 in P90 Fmr1 KO mice exposed to the AGS test, but no changes were found in P45 mice or in other brain regions. In both age groups of WT mice, p-ERK1/2-immunopositive cells increased in the subiculum after exposure to the acoustic test. Our findings illustrate that FosB/ΔFosB markers are overexpressed in the medial geniculate body and CA3 in Fmr1 KO mice experiencing AGS, and that p-ERK1/2 is markedly decreased in the subiculum of Fmr1 KO mice resistant to AGS induction. These findings suggest that resilience to AGS is associated with dephosphorylation of p-ERK1/2 in the subiculum of mature Fmr1 KO mice.

  10. Ventral tegmental area disruption selectively affects CA1/CA2 but not CA3 place fields during a differential reward working memory task.

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    Martig, Adria K; Mizumori, Sheri J Y

    2011-02-01

    Hippocampus (HPC) receives dopaminergic (DA) projections from the ventral tegmental area (VTA) and substantia nigra. These inputs appear to provide a modulatory signal that influences HPC dependent behaviors and place fields. We examined how efferent projections from VTA to HPC influence spatial working memory and place fields when the reward context changes. CA1 and CA3 process environmental context changes differently and VTA preferentially innervates CA1. Given these anatomical data and electrophysiological evidence that implicate DA in reward processing, we predicted that CA1 place fields would respond more strongly to both VTA disruption and changes in the reward context than CA3 place fields. Rats (N = 9) were implanted with infusion cannula targeting VTA and recording tetrodes aimed at HPC. Then they were tested on a differential reward, win-shift working memory task. One recording session consisted of 5 baseline and 5 manipulation trials during which place cells in CA1/CA2 (N = 167) and CA3 (N = 94) were recorded. Prior to manipulation trials rats were infused with either baclofen or saline and then subjected to control or reward conditions during which the learned locations of large and small reward quantities were reversed. VTA disruption resulted in an increase in errors, and in CA1/CA2 place field reorganization. There were no changes in any measures of CA3 place field stability during VTA disruption. Reward manipulations did not affect performance or place field stability in CA1/CA2 or CA3; however, changes in the reward locations "rescued" performance and place field stability in CA1/CA2 when VTA activity was compromised, perhaps by trigging compensatory mechanisms. These data support the hypothesis that VTA contributes to spatial working memory performance perhaps by maintaining place field stability selectively in CA1/CA2. Copyright © 2009 Wiley-Liss, Inc.

  11. High-pressure synthesis and structural, physical properties of CaIr1-xPtxO3 and CaIr1-xRhxO3

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    Hirai, S.; Bromiley, G. D.; Klemme, S.; Irifune, T.; Ohfuji, H.; Attfield, P.; Nishiyama, N.

    2010-12-01

    in terms of materials science applications. To our knowledge, this will be the first report on structural, magnetic and charge-transport properties of B-site substituted solid solutions of post-perovskite oxides with 4d/5d transition metals. High-quality polycrystalline samples of CaIr1-xPtxO3 and CaIr1-xRhxO3 have been obtained at high pressures, and structural, magnetic and charge-transport properties of the compounds will be reported. ODF analysis reveals that solutions of CaIrO3, CaPtO3 and CaRhO3 exhibit similar grain growth features to the mother compound, although growth in [0 1 0] plays a more dominant role than the growth in [0 0 1] for the solid solutions. CaIrO3 is a characteristic hard magnet suitable for applications such as magnetic recording, with TN = 108K. A new phase of CaIr1-xPtxO3 synthesized at a high P/T condition has Raman modes which resemble those of CaIrO3 perovskite, suggesting this phase has a perovskite structure.The instability of the perovskite phase of CaIr1-xPtxO3 reveals why the post-perovskite to peovskite phase transition has not been observed for CaPtO3 unlike the case for CaIrO3, CaRhO3 and CaRuO3.

  12. Ischemic damage in hippocampal CA1 is dependent on glutamate release and intact innervation from CA3

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    Benveniste, H; Jørgensen, M B; Sandberg, M

    1989-01-01

    The removal of glutamatergic afferents to CA1 by destruction of the CA3 region is known to protect CA1 pyramidal cells against 10 min of transient global ischemia. To investigate further the pathogenetic significance of glutamate, we measured the release of glutamate in intact and CA3-lesioned CA...

  13. Cannabinoids disrupt memory encoding by functionally isolating hippocampal CA1 from CA3.

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    Roman A Sandler

    2017-07-01

    Full Text Available Much of the research on cannabinoids (CBs has focused on their effects at the molecular and synaptic level. However, the effects of CBs on the dynamics of neural circuits remains poorly understood. This study aims to disentangle the effects of CBs on the functional dynamics of the hippocampal Schaffer collateral synapse by using data-driven nonparametric modeling. Multi-unit activity was recorded from rats doing an working memory task in control sessions and under the influence of exogenously administered tetrahydrocannabinol (THC, the primary CB found in marijuana. It was found that THC left firing rate unaltered and only slightly reduced theta oscillations. Multivariate autoregressive models, estimated from spontaneous spiking activity, were then used to describe the dynamical transformation from CA3 to CA1. They revealed that THC served to functionally isolate CA1 from CA3 by reducing feedforward excitation and theta information flow. The functional isolation was compensated by increased feedback excitation within CA1, thus leading to unaltered firing rates. Finally, both of these effects were shown to be correlated with memory impairments in the working memory task. By elucidating the circuit mechanisms of CBs, these results help close the gap in knowledge between the cellular and behavioral effects of CBs.

  14. CaV1.3 L-type Ca2+ channels modulate depression-like behaviour in mice independent of deaf phenotype.

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    Busquet, Perrine; Nguyen, Ngoc Khoi; Schmid, Eduard; Tanimoto, Naoyuki; Seeliger, Mathias W; Ben-Yosef, Tamar; Mizuno, Fengxia; Akopian, Abram; Striessnig, Jörg; Singewald, Nicolas

    2010-05-01

    Mounting evidence suggests that voltage-gated L-type Ca2+ channels can modulate affective behaviour. We therefore explored the role of CaV1.3 L-type Ca2+ channels in depression- and anxiety-like behaviours using CaV1.3-deficient mice (CaV1.3-/-). We showed that CaV1.3-/- mice displayed less immobility in the forced swim test as well as in the tail suspension test, indicating an antidepressant-like phenotype. Locomotor activity in the home cage or a novel open-field test was not influenced. In the elevated plus maze (EPM), CaV1.3-/- mice entered the open arms more frequently and spent more time there indicating an anxiolytic-like phenotype which was, however, not supported in the stress-induced hyperthermia test. By performing parallel experiments in Claudin 14 knockout mice (Cldn14-/-), which like CaV1.3-/- mice are congenitally deaf, an influence of deafness on the antidepressant-like phenotype could be ruled out. On the other hand, a similar EPM behaviour indicative of an anxiolytic phenotype was also found in the Cldn14-/- animals. Using electroretinography and visual behavioural tasks we demonstrated that at least in mice, CaV1.3 channels do not significantly contribute to visual function. However, marked morphological changes were revealed in synaptic ribbons in the outer plexiform layer of CaV1.3-/- retinas by immunohistochemistry suggesting a possible role of this channel type in structural plasticity at the ribbon synapse. Taken together, our findings indicate that CaV1.3 L-type Ca2+ channels modulate depression-like behaviour but are not essential for visual function. The findings raise the possibility that selective modulation of CaV1.3 channels could be a promising new therapeutic concept for the treatment of mood disorders.

  15. Elementary properties of CaV1.3 Ca2+ channels expressed in mouse cochlear inner hair cells

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    Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Lawrence, Neil D; Münkner, Stefan; Engel, Jutta; Knipper, Marlies; Magistretti, Jacopo; Masetto, Sergio; Marcotti, Walter

    2010-01-01

    Mammalian cochlear inner hair cells (IHCs) are specialized to process developmental signals during immature stages and sound stimuli in adult animals. These signals are conveyed onto auditory afferent nerve fibres. Neurotransmitter release at IHC ribbon synapses is controlled by L-type CaV1.3 Ca2+ channels, the biophysics of which are still unknown in native mammalian cells. We have investigated the localization and elementary properties of Ca2+ channels in immature mouse IHCs under near-physiological recording conditions. CaV1.3 Ca2+ channels at the cell pre-synaptic site co-localize with about half of the total number of ribbons present in immature IHCs. These channels activated at about −70 mV, showed a relatively short first latency and weak inactivation, which would allow IHCs to generate and accurately encode spontaneous Ca2+ action potential activity characteristic of these immature cells. The CaV1.3 Ca2+ channels showed a very low open probability (about 0.15 at −20 mV: near the peak of an action potential). Comparison of elementary and macroscopic Ca2+ currents indicated that very few Ca2+ channels are associated with each docked vesicle at IHC ribbon synapses. Finally, we found that the open probability of Ca2+ channels, but not their opening time, was voltage dependent. This finding provides a possible correlation between presynaptic Ca2+ channel properties and the characteristic frequency/amplitude of EPSCs in auditory afferent fibres. PMID:19917569

  16. Elementary properties of CaV1.3 Ca(2+) channels expressed in mouse cochlear inner hair cells.

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    Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Lawrence, Neil D; Münkner, Stefan; Engel, Jutta; Knipper, Marlies; Magistretti, Jacopo; Masetto, Sergio; Marcotti, Walter

    2010-01-01

    Mammalian cochlear inner hair cells (IHCs) are specialized to process developmental signals during immature stages and sound stimuli in adult animals. These signals are conveyed onto auditory afferent nerve fibres. Neurotransmitter release at IHC ribbon synapses is controlled by L-type Ca(V)1.3 Ca(2+) channels, the biophysics of which are still unknown in native mammalian cells. We have investigated the localization and elementary properties of Ca(2+) channels in immature mouse IHCs under near-physiological recording conditions. Ca(V)1.3 Ca(2+) channels at the cell pre-synaptic site co-localize with about half of the total number of ribbons present in immature IHCs. These channels activated at about 70 mV, showed a relatively short first latency and weak inactivation, which would allow IHCs to generate and accurately encode spontaneous Ca(2+) action potential activity characteristic of these immature cells. The Ca(V)1.3 Ca(2+) channels showed a very low open probability (about 0.15 at 20 mV: near the peak of an action potential). Comparison of elementary and macroscopic Ca(2+) currents indicated that very few Ca(2+) channels are associated with each docked vesicle at IHC ribbon synapses. Finally, we found that the open probability of Ca(2+) channels, but not their opening time, was voltage dependent. This finding provides a possible correlation between presynaptic Ca(2+) channel properties and the characteristic frequency/amplitude of EPSCs in auditory afferent fibres.

  17. Altered thalamocortical rhythmicity and connectivity in mice lacking CaV3.1 T-type Ca2+ channels in unconsciousness

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    Choi, Soonwook; Yu, Eunah; Lee, Seongwon; Llinás, Rodolfo R.

    2015-01-01

    In unconscious status (e.g., deep sleep and anesthetic unconsciousness) where cognitive functions are not generated there is still a significant level of brain activity present. Indeed, the electrophysiology of the unconscious brain is characterized by well-defined thalamocortical rhythmicity. Here we address the ionic basis for such thalamocortical rhythms during unconsciousness. In particular, we address the role of CaV3.1 T-type Ca2+ channels, which are richly expressed in thalamic neurons. Toward this aim, we examined the electrophysiological and behavioral phenotypes of mice lacking CaV3.1 channels (CaV3.1 knockout) during unconsciousness induced by ketamine or ethanol administration. Our findings indicate that CaV3.1 KO mice displayed attenuated low-frequency oscillations in thalamocortical loops, especially in the 1- to 4-Hz delta band, compared with control mice (CaV3.1 WT). Intriguingly, we also found that CaV3.1 KO mice exhibited augmented high-frequency oscillations during unconsciousness. In a behavioral measure of unconsciousness dynamics, CaV3.1 KO mice took longer to fall into the unconscious state than controls. In addition, such unconscious events had a shorter duration than those of control mice. The thalamocortical interaction level between mediodorsal thalamus and frontal cortex in CaV3.1 KO mice was significantly lower, especially for delta band oscillations, compared with that of CaV3.1 WT mice, during unconsciousness. These results suggest that the CaV3.1 channel is required for the generation of a given set of thalamocortical rhythms during unconsciousness. Further, that thalamocortical resonant neuronal activity supported by this channel is important for the control of vigilance states. PMID:26056284

  18. Hippocampal CA3-dentate gyrus volume uniquely linked to improvement in associative memory from childhood to adulthood.

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    Daugherty, Ana M; Flinn, Robert; Ofen, Noa

    2017-06-01

    Associative memory develops into adulthood and critically depends on the hippocampus. The hippocampus is a complex structure composed of subfields that are functionally-distinct, and anterior-posterior divisions along the length of the hippocampal horizontal axis that may also differ by cognitive correlates. Although each of these aspects has been considered independently, here we evaluate their relative contributions as correlates of age-related improvement in memory. Volumes of hippocampal subfields (subiculum, CA1-2, CA3-dentate gyrus) and anterior-posterior divisions (hippocampal head, body, tail) were manually segmented from high-resolution images in a sample of healthy participants (age 8-25 years). Adults had smaller CA3-dentate gyrus volume as compared to children, which accounted for 67% of the indirect effect of age predicting better associative memory via hippocampal volumes. Whereas hippocampal body volume demonstrated non-linear age differences, larger hippocampal body volume was weakly related to better associative memory only when accounting for the mutual correlation with subfields measured within that region. Thus, typical development of associative memory was largely explained by age-related differences in CA3-dentate gyrus. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Hippocampal CA3-dentate gyrus volume uniquely linked to improvement in associative memory from childhood to adulthood

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    Daugherty, Ana M.; Flinn, Robert; Ofen, Noa

    2017-01-01

    Associative memory develops into adulthood and critically depends on the hippocampus. The hippocampus is a complex structure composed of subfields that are functionally-distinct, and anterior-posterior divisions along the length of the hippocampal horizontal axis that may also differ by cognitive correlates. Although each of these aspects has been considered independently, here we evaluate their relative contributions as correlates of age-related improvement in memory. Volumes of hippocampal subfields (subiculum, CA1-2, CA3-dentate gyrus) and anterior-posterior divisions (hippocampal head, body, tail) were manually segmented from high-resolution proton density-weighted images in a sample of healthy participants (age 8–25 years). Adults had smaller CA3-dentate gyrus volume as compared to children, which accounted for 67% of the indirect effect of age predicting better associative memory via hippocampal volumes. Whereas hippocampal body volume demonstrated non-linear age differences, larger hippocampal body volume was weakly related to better associative memory only when accounting for the mutual correlation with subfields measured within that region. Thus, typical development of associative memory was largely explained by age-related differences in CA3-dentate gyrus. PMID:28342999

  20. Roles for the subiculum in spatial information processing, memory, motivation and the temporal control of behaviour.

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    O'Mara, Shane M; Sanchez-Vives, Maria V; Brotons-Mas, Jorge R; O'Hare, Eugene

    2009-08-01

    The subiculum is in a pivotal position governing the output of the hippocampal formation. Despite this, it is a rather under-explored and sometimes ignored structure. Here, we discuss recent data indicating that the subiculum participates in a wide range of neurocognitive functions and processes. Some of the functions of subiculum are relatively well-known-these include providing a relatively coarse representation of space and participating in, and supporting certain aspects of, memory (particularly in the dynamic bridging of temporal intervals). The subiculum also participates in a wide variety of other neurocognitive functions too, however. Much less well-known are roles for the subiculum, and particularly the ventral subiculum, in the response to fear, stress and anxiety, and in the generation of motivated behaviour (particularly the behaviour that underlies drug addiction and the response to reward). There is an emerging suggestion that the subiculum participates in the temporal control of behaviour. It is notable that these latter findings have emerged from a consideration of instrumental behaviour using operant techniques; it may well be the case that the use of the watermaze or similar spatial tasks to assess subicular function (on the presumption that its functions are very similar to the hippocampus proper) has obscured rather than revealed neurocognitive functions of subiculum. The anatomy of subiculum suggests it participates in a rather subtle fashion in a very broad range of functions, rather than in a relatively more isolated fashion in a narrower range of functions, as might be the case for "earlier" components of hippocampal circuitry, such as the CA1 and CA3 subfields. Overall, there appears to a strong dorso-ventral segregation of function within subiculum, with the dorsal subiculum relatively more concerned with space and memory, and the ventral hippocampus concerned with stress, anxiety and reward. Finally, it may be the case that the whole

  1. Lysosomes shape Ins(1,4,5)P3-evoked Ca2+ signals by selectively sequestering Ca2+ released from the endoplasmic reticulum

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    López-Sanjurjo, Cristina I.; Tovey, Stephen C.; Prole, David L.; Taylor, Colin W.

    2013-01-01

    Summary Most intracellular Ca2+ signals result from opening of Ca2+ channels in the plasma membrane or endoplasmic reticulum (ER), and they are reversed by active transport across these membranes or by shuttling Ca2+ into mitochondria. Ca2+ channels in lysosomes contribute to endo-lysosomal trafficking and Ca2+ signalling, but the role of lysosomal Ca2+ uptake in Ca2+ signalling is unexplored. Inhibition of lysosomal Ca2+ uptake by dissipating the H+ gradient (using bafilomycin A1), perforating lysosomal membranes (using glycyl-L-phenylalanine 2-naphthylamide) or lysosome fusion (using vacuolin) increased the Ca2+ signals evoked by receptors that stimulate inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] formation. Bafilomycin A1 amplified the Ca2+ signals evoked by photolysis of caged Ins(1,4,5)P3 or by inhibition of ER Ca2+ pumps, and it slowed recovery from them. Ca2+ signals evoked by store-operated Ca2+ entry were unaffected by bafilomycin A1. Video-imaging with total internal reflection fluorescence microscopy revealed that lysosomes were motile and remained intimately associated with the ER. Close association of lysosomes with the ER allows them selectively to accumulate Ca2+ released by Ins(1,4,5)P3 receptors. PMID:23097044

  2. Sustained increase of spontaneous input and spike transfer in the CA3-CA1 pathway following long term potentiation in vivo

    Directory of Open Access Journals (Sweden)

    Oscar eHerreras

    2012-10-01

    Full Text Available Long term potentiation (LTP is commonly used to study synaptic plasticity but the associated changes in the spontaneous activity of individual neurons or the computational properties of neural networks in vivo remain largely unclear. The multisynaptic origin of spontaneous spikes makes difficult estimating the impact of a particular potentiated input. Accordingly, we adopted an approach that isolates pathway-specific postsynaptic activity from raw local field potentials (LFPs in the rat hippocampus in order to study the effects of LTP on ongoing spike transfer between cell pairs in the CA3-CA1 pathway. CA1 Schaffer-specific LFPs elicited by spontaneous clustered firing of CA3 pyramidal cells involved a regular succession of elementary micro-field-EPSPs (gamma-frequency that fired spikes in CA1 units. LTP increased the amplitude but not the frequency of these ongoing excitatory quanta. Also, the proportion of Schaffer-driven spikes in both CA1 pyramidal cells and interneurons increased in a cell-specific manner only in previously connected CA3-CA1 cell pairs, i.e., when the CA3 pyramidal cell had shown pre-LTP significant correlation with firing of a CA1 unit and potentiated spike-triggered average of Schaffer LFPs following LTP. Moreover, LTP produced subtle reorganization of presynaptic CA3 cell assemblies. These findings show effective enhancement of pathway specific ongoing activity which leads to increased spike transfer in potentiated segments of a network. These indicate that plastic phenomena induced by external protocols may intensify spontaneous information flow across specific channels as proposed in transsynaptic propagation of plasticity and synfire chain hypotheses that may be the substrate for different types of memory involving multiple brain structures.

  3. Mucins CA 125, CA 19.9, CA 15.3 and TAG-72.3 as tumor markers in patients with lung cancer: comparison with CYFRA 21-1, CEA, SCC and NSE.

    Science.gov (United States)

    Molina, Rafael; Auge, Jose Maria; Escudero, Jose Miguel; Marrades, Ramon; Viñolas, Nuria; Carcereny, Emilio; Ramirez, Jose; Filella, Xavier

    2008-01-01

    Tumor marker serum levels were prospectively studied in 289 patients with suspected, but unconfirmed, lung cancer and in 513 patients with lung cancer [417 non-small cell lung cancer (NSCLC) patients and 96 small cell lung cancer (SCLC) patients]. In patients with benign disease, abnormal serum levels were found for the following tumor markers: CEA (in 6.6% of patients); CA 19.9 (6.2%); CA 125 (28.7%); NSE (0.7%); CYFRA (8.7%); TAG-72.3 (4.2%); SCC (3.5%), and CA 15.3 (3.5%). Excluding patients with renal failure or liver diseases, tumor marker specificity improved with abnormal levels in 0.5% for NSE, 0.9% for SCC, 2.8% for CEA, CA 15.3 and TAG-72.3, 3.8% for CA 19.9, 4.2% for CYFRA and 21.4% for CA 125. Excluding CA 125, one of the markers was abnormal in 15% of patients without malignancy. Tumor marker sensitivity was related to cancer histology and tumor extension. NSE had the highest sensitivity in SCLC and CYFRA and CEA in NSCLC. Significantly higher concentrations of CEA, SCC, CA 125, CA 15.3 and TAG-72.3 were found in NSCLC than in SCLC. Likewise, significantly higher CEA (p tumors. Using a combination of 3 tumor markers (CEA, CYFRA 21-1 in all histologies, SCC in squamous tumors and CA 15.3 in adenocarcinomas), a high sensitivity may be achieved in all histological types. Tumor markers may be useful in the histological differentiation of NSCLC and SCLC. Using specific criteria for the differentiation of SCLC and NSCLC, the sensitivity was 84.2 and 68.8%, the specificity was 93.8 and 99.7%, the positive predictive value was 98.3 and 98.5% and the negative predictive value was 57.7 and 93.3%, respectively. Copyright 2008 S. Karger AG, Basel.

  4. Thermoelectric properties of Ca1-xYxMnO3 and Ca0.9Y0.1-yFeyMnO3 perovskite compounds

    DEFF Research Database (Denmark)

    Thuy, Nguyen Thi; Minh, Dang Le; Van Nong, Ngo

    2012-01-01

    Polycrystalline Ca1-xYxMnO3 (x = 0.0; 0.1; 0.3; 0.5; 0.7) and Ca0.9Y0.1-yFeyMnO3 (y = 0.00; 0.01; 0.03; 0.05) compounds were prepared by solid-state reaction. X-ray diffraction (XRD) analysis revealed all XRD peaks of all the samples as identical to the orthorhombic structure. The thermoelectric ...

  5. The functional genome of CA1 and CA3 neurons under native conditions and in response to ischemia

    Directory of Open Access Journals (Sweden)

    Rossner Moritz

    2007-10-01

    Full Text Available Abstract Background The different physiological repertoire of CA3 and CA1 neurons in the hippocampus, as well as their differing behaviour after noxious stimuli are ultimately based upon differences in the expressed genome. We have compared CA3 and CA1 gene expression in the uninjured brain, and after cerebral ischemia using laser microdissection (LMD, RNA amplification, and array hybridization. Results Profiling in CA1 vs. CA3 under normoxic conditions detected more than 1000 differentially expressed genes that belong to different, physiologically relevant gene ontology groups in both cell types. The comparison of each region under normoxic and ischemic conditions revealed more than 5000 ischemia-regulated genes for each individual cell type. Surprisingly, there was a high co-regulation in both regions. In the ischemic state, only about 100 genes were found to be differentially expressed in CA3 and CA1. The majority of these genes were also different in the native state. A minority of interesting genes (e.g. inhibinbetaA displayed divergent expression preference under native and ischemic conditions with partially opposing directions of regulation in both cell types. Conclusion The differences found in two morphologically very similar cell types situated next to each other in the CNS are large providing a rational basis for physiological differences. Unexpectedly, the genomic response to ischemia is highly similar in these two neuron types, leading to a substantial attenuation of functional genomic differences in these two cell types. Also, the majority of changes that exist in the ischemic state are not generated de novo by the ischemic stimulus, but are preexistant from the genomic repertoire in the native situation. This unexpected influence of a strong noxious stimulus on cell-specific gene expression differences can be explained by the activation of a cell-type independent conserved gene-expression program. Our data generate both novel

  6. Sol–gel synthesis and photoluminescence of CaTi1–x Zrx O3: Pr 3 ...

    Indian Academy of Sciences (India)

    The strongest red excitation obtained from CaTi1–ZrO3 : Pr3+ ( = 4/300) and CaTi1–ZrO3 : Pr3+ ( = 5/300) possesses the strongest emission at 610 nm, similar to the intensities of Ca(Ti1–Zr)O3 : Pr3+ ( = 3/300, 4/300, 6/300), which may be corresponded to the cell parameters of CaTi1–ZrO3 : Pr3+.

  7. Structure determinations for Ca3Ti2O7, Ca4Ti3O10, Ca3.6Sr0.4Ti3O10 and a refinement of Sr3Ti2O7

    International Nuclear Information System (INIS)

    Elcombe, M.M.; Kisi, E.H.; Hawkins, K.D.; White, T.J.; Goodman, P.; Matheson, S.

    1991-01-01

    The structures of the orthorhombic Ruddlesden-Popper (A n+1 B n X 3n+1 ) phases Ca 3 Ti 2 O 7 (n=2) refined from neutron powder diffraction data at λ=1.893 A. They consist of coherent intergrowths of perovskite (CaTiO 3 ) blocks, n TiO 6 octahedra thick, with single layers of CaO having a distorted NaCl configuration. TiO 6 octahedra are tilted and distorted in a very similar fashion to those in CaTiO 3 (n=∞). This fact was used to determine the space groups of the layered structures. Convergent-beam electron diffraction patterns are best matched by calculations in the above space groups which are thus confirmed. Octahedral tilt angles increase slightly in the sequence n=2, 3, ∞. Strontium addition reduces the octahedral tilt angles because of preferential substitution of Sr on the Ca sites within the perovskite blocks of Ca 4 Ti 3 O 10 . The algorithm used to produce starting models for structure refinements is thought to be generally applicable to Ruddlesden-Popper and possibly other layered perovskite structures. It furnishes the predictions: (a) all n-even compounds in the Ca n+1 Ti n O 3n+1 series will have space group Ccm2 1 , (b) all n-odd compounds in this series will have space group Pcab, (c) all A n+1 B n X 3n+1 series for which the n=∞ end member (ABX 3 ) is isostructural with CaTiO 3 will be isostructural with the compounds reported above (e.g. Ca n+1 Zr n O 3n+1 ). (orig./WL)

  8. Electrical and microstructural properties of CaTiO3-doped K1/2Na1 ...

    Indian Academy of Sciences (India)

    KNN) and CaTiO3- modified K1/2Na1/2NbO3 (CTO-KNN) systems, were investigated. Discs doped with 0 to 0.55% mol of CaTiO3 (CTO) were sintered at 1125°C for 2 h. Although minority phases were found in doped samples, CaTiO3 was not ...

  9. Thermoluminescence of CaCO3:Dy and CaCO3:Mn

    International Nuclear Information System (INIS)

    Bapat, V.N.; Nambi, K.S.V.

    1976-01-01

    CaCO 3 samples doped with Dy and Mn were prepared in the laboratory by co-precipitation techniques. Thermoluminescence and emission spectra of these phosphors were studied and were compared with those of the naturally occuring calcite and undoped CaCO 3 samples. Dy-doping seems to give a more efficient phosphor and indicates a possibility of getting a better phosphor by a judicious choice of a rare earth doping of CaCO 3 . Interesting result have been obtained on the TL glow curve variations of these phosphors with different temperature treatments prior to irradiation. (author)

  10. The CaV2.3 R-type voltage-gated Ca2+ channel in mouse sleep architecture.

    Science.gov (United States)

    Siwek, Magdalena Elisabeth; Müller, Ralf; Henseler, Christina; Broich, Karl; Papazoglou, Anna; Weiergräber, Marco

    2014-05-01

    Voltage-gated Ca(2+) channels (VGCCs) are key elements in mediating thalamocortical rhythmicity. Low-voltage activated (LVA) CaV 3 T-type Ca(2+) channels have been related to thalamic rebound burst firing and to generation of non-rapid eye movement (NREM) sleep. High-voltage activated (HVA) CaV 1 L-type Ca(2+) channels, on the opposite, favor the tonic mode of action associated with higher levels of vigilance. However, the role of the HVA Non-L-type CaV2.3 Ca(2+) channels, which are predominantly expressed in the reticular thalamic nucleus (RTN), still remains unclear. Recently, CaV2.3(-/-) mice were reported to exhibit altered spike-wave discharge (SWD)/absence seizure susceptibility supported by the observation that CaV2.3 mediated Ca(2+) influx into RTN neurons can trigger small-conductance Ca(2+)-activated K(+)-channel type 2 (SK2) currents capable of maintaining thalamic burst activity. Based on these studies we investigated the role of CaV2.3 R-type Ca(2+) channels in rodent sleep. The role of CaV2.3 Ca(2+) channels was analyzed in CaV2.3(-/-) mice and controls in both spontaneous and artificial urethane-induced sleep, using implantable video-EEG radiotelemetry. Data were analyzed for alterations in sleep architecture using sleep staging software and time-frequency analysis. CaV2.3 deficient mice exhibited reduced wake duration and increased slow-wave sleep (SWS). Whereas mean sleep stage durations remained unchanged, the total number of SWS epochs was increased in CaV2.3(-/-) mice. Additional changes were observed for sleep stage transitions and EEG amplitudes. Furthermore, urethane-induced SWS mimicked spontaneous sleep results obtained from CaV2.3 deficient mice. Quantitative Real-time PCR did not reveal changes in thalamic CaV3 T-type Ca(2+) channel expression. The detailed mechanisms of SWS increase in CaV2.3(-/-) mice remain to be determined. Low-voltage activated CaV2.3 R-type Ca(2+) channels in the thalamocortical loop and extra

  11. Ensemble place codes in hippocampus: CA1, CA3, and dentate gyrus place cells have multiple place fields in large environments.

    Directory of Open Access Journals (Sweden)

    Eunhye Park

    Full Text Available Previously we reported that the hippocampus place code must be an ensemble code because place cells in the CA1 region of hippocampus have multiple place fields in a more natural, larger-than-standard enclosure with stairs that permitted movements in 3-D. Here, we further investigated the nature of hippocampal place codes by characterizing the spatial firing properties of place cells in the CA1, CA3, and dentate gyrus (DG hippocampal subdivisions as rats foraged in a standard 76-cm cylinder as well as a larger-than-standard box (1.8 m×1.4 m that did not have stairs or any internal structure to permit movements in 3-D. The rats were trained to forage continuously for 1 hour using computer-controlled food delivery. We confirmed that most place cells have single place fields in the standard cylinder and that the positional firing pattern remapped between the cylinder and the large enclosure. Importantly, place cells in the CA1, CA3 and DG areas all characteristically had multiple place fields that were irregularly spaced, as we had reported previously for CA1. We conclude that multiple place fields are a fundamental characteristic of hippocampal place cells that simplifies to a single field in sufficiently small spaces. An ensemble place code is compatible with these observations, which contradict any dedicated coding scheme.

  12. Multiple C-terminal tail Ca(2+)/CaMs regulate Ca(V)1.2 function but do not mediate channel dimerization.

    Science.gov (United States)

    Kim, Eun Young; Rumpf, Christine H; Van Petegem, Filip; Arant, Ryan J; Findeisen, Felix; Cooley, Elizabeth S; Isacoff, Ehud Y; Minor, Daniel L

    2010-12-01

    Interactions between voltage-gated calcium channels (Ca(V)s) and calmodulin (CaM) modulate Ca(V) function. In this study, we report the structure of a Ca(2+)/CaM Ca(V)1.2 C-terminal tail complex that contains two PreIQ helices bridged by two Ca(2+)/CaMs and two Ca(2+)/CaM-IQ domain complexes. Sedimentation equilibrium experiments establish that the complex has a 2:1 Ca(2+)/CaM:C-terminal tail stoichiometry and does not form higher order assemblies. Moreover, subunit-counting experiments demonstrate that in live cell membranes Ca(V)1.2s are monomers. Thus, contrary to previous proposals, the crystallographic dimer lacks physiological relevance. Isothermal titration calorimetry and biochemical experiments show that the two Ca(2+)/CaMs in the complex have different properties. Ca(2+)/CaM bound to the PreIQ C-region is labile, whereas Ca(2+)/CaM bound to the IQ domain is not. Furthermore, neither of lobes of apo-CaM interacts strongly with the PreIQ domain. Electrophysiological studies indicate that the PreIQ C-region has a role in calcium-dependent facilitation. Together, the data show that two Ca(2+)/CaMs can bind the Ca(V)1.2 tail simultaneously and indicate a functional role for Ca(2+)/CaM at the C-region site.

  13. Identification of expressed genes in cDNA library of hemocytes from the RLO-challenged oyster, Crassostrea ariakensis Gould with special functional implication of three complement-related fragments (CaC1q1, CaC1q2 and CaC3).

    Science.gov (United States)

    Xu, Ting; Xie, Jiasong; Li, Jianming; Luo, Ming; Ye, Shigen; Wu, Xinzhong

    2012-06-01

    A SMARTer™ cDNA library of hemocyte from Rickettsia-like organism (RLO) challenged oyster, Crassostrea ariakensis Gould was constructed. Random clones (400) were selected and single-pass sequenced, resulted in 200 unique sequences containing 96 known genes and 104 unknown genes. The 96 known genes were categorized into 11 groups based on their biological process. Furthermore, we identified and characterized three complement-related fragments (CaC1q1, CaC1q2 and CaC3). Tissue distribution analysis revealed that all of three fragments were ubiquitously expressed in all tissues studied including hemocyte, gills, mantle, digestive glands, gonads and adductor muscle, while the highest level was seen in the hemocyte. Temporal expression profile in the hemocyte monolayers reveled that the mRNA expression levels of three fragments presented huge increase after the RLO incubation at 3 h and 6 h in post-challenge, respectively. And the maximal expression levels at 3 h in post-challenge are about 256, 104 and 64 times higher than the values detected in the control of CaC1q1, CaC1q2 and CaC3, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. CaV3.1 is a tremor rhythm pacemaker in the inferior olive

    Science.gov (United States)

    Park, Young-Gyun; Park, Hye-Yeon; Lee, C. Justin; Choi, Soonwook; Jo, Seonmi; Choi, Hansol; Kim, Yang-Hann; Shin, Hee-Sup; Llinas, Rodolfo R.; Kim, Daesoo

    2010-01-01

    The rhythmic motor pathway activation by pacemaker neurons or circuits in the brain has been proposed as the mechanism for the timing of motor coordination, and the abnormal potentiation of this mechanism may lead to a pathological tremor. Here, we show that the potentiation of CaV3.1 T-type Ca2+ channels in the inferior olive contributes to the onset of the tremor in a pharmacological model of essential tremor. After administration of harmaline, 4- to 10-Hz synchronous neuronal activities arose from the IO and then propagated to cerebellar motor circuits in wild-type mice, but those rhythmic activities were absent in mice lacking CaV3.1 gene. Intracellular recordings in brain-stem slices revealed that the CaV3.1-deficient inferior olive neurons lacked the subthreshold oscillation of membrane potentials and failed to trigger 4- to 10-Hz rhythmic burst discharges in the presence of harmaline. In addition, the selective knockdown of CaV3.1 gene in the inferior olive by shRNA efficiently suppressed the harmaline-induced tremor in wild-type mice. A mathematical model constructed based on data obtained from patch-clamping experiments indicated that harmaline could efficiently potentiate CaV3.1 channels by changing voltage-dependent responsiveness in the hyperpolarizing direction. Thus, CaV3.1 is a molecular pacemaker substrate for intrinsic neuronal oscillations of inferior olive neurons, and the potentiation of this mechanism can be considered as a pathological cause of essential tremor. PMID:20498062

  15. Possibility of adjusting the photoluminescence spectrum of Ca scheelites to the emission spectrum of incandescent lamps: [ nCaWO4-(1- n)CaMoO4]: Eu3+ solid solutions

    Science.gov (United States)

    Bakovets, V. V.; Zolotova, E. S.; Antonova, O. V.; Korol'kov, I. V.; Yushina, I. V.

    2016-12-01

    The specific features of the photoluminescence of [ nCaWO4-(1- n)CaMoO4]:Eu3+ solid solutions with the scheelite structure are examined using X-ray phase analysis and photoluminescence, Raman scattering, and diffuse reflectance spectroscopy. The studied features are associated with a change in the long- and short-range orders of the crystal lattice upon variations in the composition of solutions in the range n = 0-1.0 (with a pitch of 0.2) at a concentration of red photoluminescence activator Eu3+ of 2 mol %. The mechanism of the modification of photoluminescence of solid solutions upon variations in their composition has been discussed. Anomalies in the variations in parameters of the crystal lattice, its short-range order, and luminescence spectra have been observed in the transition from pure compounds CaMoO4:Eu3+ and CaWO4:Eu3+ to solutions; the concentration of Eu3+ ions in the centrosymmetric localization increases (decreases) in the transition from the molybdate (tungstate). It has been demonstrated that the spectral radiant emittance of solid solution [0.4CaWO4-0.6CaMoO4]:Eu3+ (2 mol %) is the closest to that of an incandescent lamp.

  16. Value of Combined Detection of Serum CEA, CA72-4, CA19-9, CA15-3 and CA12-5 in the Diagnosis of Gastric Cancer.

    Science.gov (United States)

    Chen, Changguo; Chen, Qiuyuan; Zhao, Qiangyuan; Liu, Min; Guo, Jianwei

    2017-05-01

    To examine whether the combined detection of serum tumor markers (CEA, CA72-4, CA19-9, CA15-3 and CA12-5) improves the sensitivity and accuracy in the diagnosis of gastric cancer (GC). An automatic chemiluminescence immune analyzer with matched kits was used to determine the levels of serum CEA, CA72-4, CA19-9, CA15-3, and CA12-5 in 87 patients with gastric cancer (GC group), 60 patients with gastric benign diseases (GBD group) who were hospitalized during the same period, and 40 healthy subjects undergoing a physical examination. The values of these 5 tumor markers in the diagnosis of gastric cancer were analyzed. The levels of serum CEA, CA72-4, CA19-9, and CA12-5 were higher in the GC group than in the GBD group and healthy subjects, and these differences were significant ( P 0.05). The combined detection of CEA, CA72-4, CA19-9, and CA12-5 had a higher diagnostic value for gastric cancer than did single detection, and the positive detection rate of the combined detection of the four tumor markers was 60.9%. The diagnostic power when using the combined detection of CA72-4, CEA, CA19-9, and CA12-5 was the best. The combined detection of serum CA72-4, CEA, CA19-9 and CA12-5 increases the sensitivity and accuracy in the diagnosis of GC and can thus be considered an important tool for early diagnosis. © 2017 by the Association of Clinical Scientists, Inc.

  17. Prenatal nicotine and maternal deprivation stress de-regulate the development of CA1, CA3, and dentate gyrus neurons in hippocampus of infant rats.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Adverse experiences by the developing fetus and in early childhood are associated with profound effects on learning, emotional behavior, and cognition as a whole. In this study we investigated the effects of prenatal nicotine exposure (NIC, postnatal maternal deprivation (MD or the combination of the two (NIC+MD to determine if hippocampal neuron development is modulated by exposure to drugs of abuse and/or stress. Growth of rat offspring exposed to MD alone or NIC+MD was repressed until after weaning. In CA1 but not CA3 of postnatal day 14 (P14 pups, MD increased pyramidal neurons, however, in dentate gyrus (DG, decreased granule neurons. NIC had no effect on neuron number in CA1, CA3 or DG. Unexpectedly, NIC plus MD combined caused a synergistic increase in the number of CA1 or CA3 neurons. Neuron density in CA regions was unaffected by treatment, but in the DG, granule neurons had a looser packing density after NIC, MD or NIC+MD exposure. When septotemporal axes were analyzed, the synergism of stress and drug exposure in CA1 and CA3 was associated with rostral, whereas MD effects were predominantly associated with caudal neurons. TUNEL labeling suggests no active apoptosis at P14, and doublecortin positive neurons and mossy fibers were diminished in NIC+MD relative to controls. The laterality of the effect of nicotine and/or maternal deprivation in right versus left hippocampus was also analyzed and found to be insiginificant. We report for the first time that early life stressors such as postnatal MD and prenatal NIC exposure, when combined, may exhibit synergistic consequences for CA1 and CA3 pyramidal neuron development, and a potential antagonistic influence on developing DG neurons. These results suggest that early stressors may modulate neurogenesis, apoptosis, or maturation of glutamatergic neurons in the hippocampus in a region-specific manner during critical periods of neurodevelopment.

  18. IP3 stimulates CA++ efflux from fusogenic carrot protoplasts

    International Nuclear Information System (INIS)

    Rincon, M.; Boss, W.F.

    1986-01-01

    Polyphosphoinositide breakdown plays an important role in signal transduction in animal cells (Berridge and Irvine, 1984, Nature, 312:315). Upon stimulation, phospholipase C hydrolyzes phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate (IP 3 ) and diacylglycerol both of which act as cellular second messengers. IP 3 mobilizes Ca ++ from internal stores, hence the cytosolic free Ca ++ concentration increases and those physiological activities regulated by Ca ++ are stimulated. To test if plant cells also responded to IP 3 , Ca ++ efflux studies were done with fusogenic carrot protoplasts released in EGTA. The protoplasts were preloaded with 45 Ca ++ placed in a Ca ++ -free medium, and efflux determined as 45 Ca ++ loss from the protoplasts. IP 3 (10-20μM) caused enhanced 45 Ca ++ efflux and the response was sustained for at least 15 min. In plants, as in animals, the observed IP 3 -enhanced 45 Ca ++ efflux suggested that IP 3 released Ca ++ from internal stores, and the increased free cytosolic Ca ++ activated Ca ++ pumping mechanisms which restored the Ca ++ concentration in the cytosol to the normal level

  19. Electrical and magnetic behavior of La0.7Ca0.3MnO3/La0.7Sr0.2Ca0.1MnO3 composites

    International Nuclear Information System (INIS)

    Phong, P.T.; Dai, N.V.; Manh, D.H.; Thanh, T.D.; Khiem, N.V.; Hong, L.V.; Phuc, N.X.

    2010-01-01

    The electrical transport properties and the magnetoresistance of La 0.7 Ca 0.3 MnO 3 /La 0.7 Sr 0.2 Ca 0.1 MnO 3 composites are investigated as a function of sintering temperature. On the basis of an analysis by X-ray powder diffraction and scanning electron microscopy we suggest that raising the sintering temperature enhanced the interfacial reaction and creates interfacial phases at the boundaries of the La 0.7 Ca 0.3 MnO 3 and La 0.7 Sr 0.2 Ca 0.1 MnO 3 . Results also show that in 3 kOe, and at the Curie temperature, the magnetoresistance value of 14% was observed for the composite sintered at 1300 o C. Based on the phenomenological equation for conductivity under a percolation approach, which depends on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions, we fitted the experimental resistivity-temperature data from 50-300 K and find that the activation barrier decreases as temperature is increased.

  20. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex

    Directory of Open Access Journals (Sweden)

    Shih-pi Ku

    2017-07-01

    Full Text Available The subiculum and the lateral entorhinal cortex (LEC are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1 receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum, both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors. This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval.

  1. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex.

    Science.gov (United States)

    Ku, Shih-Pi; Nakamura, Nozomu H; Maingret, Nicolas; Mahnke, Liv; Yoshida, Motoharu; Sauvage, Magdalena M

    2017-01-01

    The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc , which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval.

  2. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex

    Science.gov (United States)

    Ku, Shih-pi; Nakamura, Nozomu H.; Maingret, Nicolas; Mahnke, Liv; Yoshida, Motoharu; Sauvage, Magdalena M.

    2017-01-01

    The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval. PMID:28790897

  3. Control theory-based regulation of hippocampal CA1 nonlinear dynamics.

    Science.gov (United States)

    Hsiao, Min-Chi; Song, Dong; Berger, Theodore W

    2008-01-01

    We are developing a biomimetic electronic neural prosthesis to replace regions of the hippocampal brain area that have been damaged by disease or insult. Our previous study has shown that the VLSI implementation of a CA3 nonlinear dynamic model can functionally replace the CA3 subregion of the hippocampal slice. As a result, the propagation of temporal patterns of activity from DG-->VLSI-->CA1 reproduces the activity observed experimentally in the biological DG-->CA3-->CA1 circuit. In this project, we incorporate an open-loop controller to optimize the output (CA1) response. Specifically, we seek to optimize the stimulation signal to CA1 using a predictive dentate gyrus (DG)-CA1 nonlinear model (i.e., DG-CA1 trajectory model) and a CA1 input-output model (i.e., CA1 plant model), such that the ultimate CA1 response (i.e., desired output) can be first predicted by the DG-CA1 trajectory model and then transformed to the desired stimulation through the inversed CA1 plant model. Lastly, the desired CA1 output is evoked by the estimated optimal stimulation. This study will be the first stage of formulating an integrated modeling-control strategy for the hippocampal neural prosthetic system.

  4. Impaired expression of GABA transporters in the human Alzheimer's disease hippocampus, subiculum, entorhinal cortex and superior temporal gyrus.

    Science.gov (United States)

    Fuhrer, Tessa E; Palpagama, Thulani H; Waldvogel, Henry J; Synek, Beth J L; Turner, Clinton; Faull, Richard L; Kwakowsky, Andrea

    2017-05-20

    Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the brain and plays an important role in regulating neuronal excitability. GABA reuptake from the synapse is dependent on specific transporters - mainly GAT-1, GAT-3 and BGT-1 (GATs). This study is the first to show alterations in the expression of the GATs in the Alzheimer's disease (AD) hippocampus, entorhinal cortex and superior temporal gyrus. We found a significant increase in BGT-1 expression associated with AD in all layers of the dentate gyrus, in the stratum oriens of the CA2 and CA3 and the superior temporal gyrus. In AD there was a significant decrease in GAT-1 expression in the entorhinal cortex and superior temporal gyrus. We also found a significant decrease in GAT-3 immunoreactivity in the stratum pyramidale of the CA1 and CA3, the subiculum and entorhinal cortex. These observations indicate that the expression of the GATs shows brain-region- and layer-specific alterations in AD, suggesting a complex activation pattern of different GATs during the course of the disease. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  5. The diagnostic value of serum tumor markers CEA, CA19-9, CA125, CA15-3, and TPS in metastatic breast cancer.

    Science.gov (United States)

    Wang, Weigang; Xu, Xiaoqin; Tian, Baoguo; Wang, Yan; Du, Lili; Sun, Ting; Shi, Yanchun; Zhao, Xianwen; Jing, Jiexian

    2017-07-01

    This study aims to understand the diagnostic value of serum tumor markers carcinoembryonic antigen (CEA), cancer antigen 19-9 (CA19-9), cancer antigen 125 (CA125), cancer antigen 15-3 (CA15-3), and tissue polypeptide-specific antigen (TPS) in metastatic breast cancer (MBC). A total of 164 metastatic breast cancer patients in Shanxi Cancer Hospital were recruited between February 2016 and July 2016. 200 breast cancer patients without metastasis in the same period were randomly selected as the control group. The general characteristics, immunohistochemical, and pathological results were investigated between the two groups, and tumor markers were determined. There were statistical differences in the concentration and the positive rates of CEA, CA19-9, CA125, CA15-3, and TPS between the MBC and control group (Ptumor marker at 56.7% and 97.0%, respectively. In addition, two tumor markers were used for the diagnosis of MBC and the CEA and TPS combination had the highest diagnostic sensitivity with 78.7%, while the CA15-3 and CA125 combination had the highest specificity of 91.5%. Analysis of tumor markers of 164 MBC found that there were statistical differences in the positive rates of CEA and CA15-3 between bone metastases and other metastases (χ 2 =6.00, P=0.014; χ 2 =7.32, P=0.007, respectively). The sensitivity and specificity values of the CEA and CA15-3 combination in the diagnosis of bone metastases were 77.1% and 45.8%, respectively. The positive rate of TPS in the lung metastases group was lower than in other metastases (χ 2 =8.06, P=0.005).There were significant differences in the positive rates of CA15-3 and TPS between liver metastases and other metastases (χ 2 =15.42, Ptumor markers have varying diagnostic value. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Low temperature synthesis of CaZrO3 nanoceramics from CaCl2–NaCl molten eutectic salt

    Directory of Open Access Journals (Sweden)

    Rahman Fazli

    2015-06-01

    Full Text Available CaZrO3 nanoceramics were successfully synthesized at 700 C using the molten salt method, and the effects of processing parameters, such as temperature, holding time, and amount of salt on the crystallization of CaZrO3 were investigated. CaCl2, Na2CO3, and nano-ZrO2 were used as starting materials. On heating, CaCl2–NaCl molten eutectic salt provided a liquid medium for the reaction of CaCO3 and ZrO2 to form CaZrO3. The results demonstrated that CaZrO3 started to form at about 600C and that, after the temperature was increased to 1,000C, the amounts of CaZrO3 in the resultant powders increased with a concomitant decrease in CaCO3and ZrO2 contents. After washing with hot distilled water, the samples heated for 3 h at 700C were single-phase CaZrO3 with 90–95 nm particle size. Furthermore, the synthesized CaZrO3 particles retained the size and morphology of the ZrO2 powders which indicated that a template mechanism dominated the formation of CaZrO3 by molten-salt method.

  7. Mechanosynthesis of nanocrystalline CaTi1-xMnxO3

    Directory of Open Access Journals (Sweden)

    Figueiredo, F. M.

    2008-08-01

    Full Text Available The mechanosynthesis of nanocrystalline CaTi1-xMnxO3-δ is reported for the first time. Powdered CaO, TiO2 anatase and Mn2O3 (Aldrich were weighed in the appropriate stoichiometric quantities in order to obtain CaTi1-xMnxO3-δ (x=0.05, 0.10, 0.15, 0.20, 0.30, 0.50 and 0.80 and dry milled in a planetary high-energy ball mill, using zirconia containers and balls, with a 10:1 ball/mass ratio. The planetary rotation was kept constant at 650 rpm and the container at 1300 rpm, in the opposite direction. Powder XRD patterns revealed a perovskite forming from the early milling stages and a completed reaction after 180 min, with no apparent crystalline or amorphous intermediates, indicating significant Mn solubility in CaTiO3. Patterns show a decrease in lattice volume upon Mn substitution, as expected from the lower Mn3+ or Mn4+ ionic radii when compared to Ti4+. The average crystallite size is in the range 5-30 nm, as determined from Williamson-Hall plots and confirmed by high resolution transmission electron microscopy.La mecanosíntesis de CaTi1-xMnxO3-δ nanocristalino es presentada por primera vez. Polvos reactivos de CaO, TiO2 anatasa y Mn2O3 (Aldrich fueron pesados en las cantidades estequiométricas adecuadas para obtener CaTi1-xMnxO3-δ (x=0.05, 0.10, 0.15, 0.20, 0.30, 0.50 y 0.80 por molienda en seco en un molino planetario de alta energía utilizando contenedores y bolas de circona, en una relación masa de bolas : masa de polvo de 10:1. La rotación del planetario se mantuvo constante a 650 revoluciones por minuto (rpm y la del contenedor a 1300 rpm, en el sentido inverso. La formación de una fase con estructura de perovskita fue identificada a través del análisis de los polvos por difracción de rayos X, siendo esta fase claramente mayoritaria en los polvo molidos durante 180 min y sin observarse la formación de compuestos intermediarios. Los patrones de difracción de rayos X también indicaron una disminución de los parámetro de red

  8. Neutron investigation of Ru-doped Nd1/2Ca1/2MnO3. Comparison with Cr-doped Nd1/2Ca1/2MnO3

    International Nuclear Information System (INIS)

    Moritomo, Yutaka; Nonobe, Toshihiko; Machida, Akihiko; Ohoyama, Kenji

    2002-01-01

    Lattice and magnetic properties are investigated for 3% Ru- and Cr-doped Nd 1/2 Ca 1/2 MnO 3 . The parent Nd 1/2 Ca 1/2 MnO 3 is a charge-ordered insulator (T CO =250K). With decreasing temperature below ≅210K, these compounds are separated into two perovskite phases, that is, the long-c and short-c phases. The long-c region shows a ferromagnetic transition at T C ≅210K for the Ru-doped compound and ≅130K for the Cr-doped compound, while the short-c region shows antiferromagnetic transition at T N ≅150K for Ru and ≅110K for Cr. We discuss the origin of the enhanced T C for the Ru-doped compound in terms of the effective one-electron bandwidth W of the e g -band. (author)

  9. Inhomogeneous ferrimagnetic-like behavior in Gd2/3Ca1/3MnO3 single crystals

    International Nuclear Information System (INIS)

    Haberkorn, N.; Larregola, S.; Franco, D.; Nieva, G.

    2009-01-01

    We present a study of the magnetic properties of Gd 2/3 Ca 1/3 MnO 3 single crystals at low temperatures, showing that this material behaves as an inhomogeneous ferrimagnet. In addition to small saturation magnetization at 5 K, we have found history dependent effects in the magnetization and the presence of exchange bias. These features are compatible with microscopic phase separation in the clean Gd 2/3 Ca 1/3 MnO 3 system studied

  10. Cation-exchange antibody labeling for simultaneous electrochemical detection of tumor markers CA15-3 and CA19-9

    International Nuclear Information System (INIS)

    Wang, Guangjie; Qing, Yi; Shan, Jinlu; Jin, Feng; Wang, Dong; Yuan, Ruo

    2013-01-01

    We report on a new kind of non-covalent multi-label electrochemical immunoassay that was applied to simultaneously quantify the tumor markers CA15-3 and CA19-9. The method employs a nanohybrid composed of an ionomer and conductive titanium dioxide nanoparticles that act as a matrix support for the antibodies. The two antibodies (anti-CA153 and anti-CA199) were labeled (a) with a cobaltous dipyridine complex, and (b) with methylene blue. Labeling is based on cation-exchange interaction rather than on covalent conjugation. The redox potentials of the two labels are separated by an interval of 0.3 V. The resulting sandwich-type immunosensor was read out by differential pulse voltammetry. The potential sites and currents of the two redox probes reflect the concentration of the two analytes. The two analytes were determined with a detection limit of 1.6 U mL −1 for CA19-9, and of 0.3 U mL −1 for CA15-3 (author)

  11. Ab-initio calculations of the Ruddlesden-Popper phases CaMnO3, CaO(CaMnO3) and CaO(CaMnO3)2

    International Nuclear Information System (INIS)

    Cardoso, C; Borges, R P; Gasche, T; Godinho, M

    2008-01-01

    The present work reports ab-initio density functional theory calculations for the Ruddlesden-Popper phase CaO(CaMnO 3 ) n compounds. In order to study the evolution of the properties with the number of perovskite layers, a detailed analysis of the densities of states calculated for each compound and for several magnetic configurations was performed. The effect of distortions of the crystal structure on the magnetic ground state is also analysed and the exchange constants and transition temperatures are calculated for the three compounds using a mean field model. The calculated magnetic ground state structures and magnetic moments are in good agreement with experimental results and previous calculations

  12. Functional properties of a newly identified C-terminal splice variant of Cav1.3 L-type Ca2+ channels.

    Science.gov (United States)

    Bock, Gabriella; Gebhart, Mathias; Scharinger, Anja; Jangsangthong, Wanchana; Busquet, Perrine; Poggiani, Chiara; Sartori, Simone; Mangoni, Matteo E; Sinnegger-Brauns, Martina J; Herzig, Stefan; Striessnig, Jörg; Koschak, Alexandra

    2011-12-09

    An intramolecular interaction between a distal (DCRD) and a proximal regulatory domain (PCRD) within the C terminus of long Ca(v)1.3 L-type Ca(2+) channels (Ca(v)1.3(L)) is a major determinant of their voltage- and Ca(2+)-dependent gating kinetics. Removal of these regulatory domains by alternative splicing generates Ca(v)1.3(42A) channels that activate at a more negative voltage range and exhibit more pronounced Ca(2+)-dependent inactivation. Here we describe the discovery of a novel short splice variant (Ca(v)1.3(43S)) that is expressed at high levels in the brain but not in the heart. It lacks the DCRD but, in contrast to Ca(v)1.3(42A), still contains PCRD. When expressed together with α2δ1 and β3 subunits in tsA-201 cells, Ca(v)1.3(43S) also activated at more negative voltages like Ca(v)1.3(42A) but Ca(2+)-dependent inactivation was less pronounced. Single channel recordings revealed much higher channel open probabilities for both short splice variants as compared with Ca(v)1.3(L). The presence of the proximal C terminus in Ca(v)1.3(43S) channels preserved their modulation by distal C terminus-containing Ca(v)1.3- and Ca(v)1.2-derived C-terminal peptides. Removal of the C-terminal modulation by alternative splicing also induced a faster decay of Ca(2+) influx during electrical activities mimicking trains of neuronal action potentials. Our findings extend the spectrum of functionally diverse Ca(v)1.3 L-type channels produced by tissue-specific alternative splicing. This diversity may help to fine tune Ca(2+) channel signaling and, in the case of short variants lacking a functional C-terminal modulation, prevent excessive Ca(2+) accumulation during burst firing in neurons. This may be especially important in neurons that are affected by Ca(2+)-induced neurodegenerative processes.

  13. Vibrational spectroscopic study of poldervaartite CaCa[SiO3(OH)(OH)

    Science.gov (United States)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Lima, Rosa Malena Fernandes

    2015-02-01

    We have studied the mineral poldervaartite CaCa[SiO3(OH)(OH)] which forms a series with its manganese analogue olmiite CaMn[SiO3(OH)](OH) using a range of techniques including scanning electron microscopy, thermogravimetric analysis, Raman and infrared spectroscopy. Chemical analysis shows the mineral is reasonably pure and contains only calcium and manganese with low amounts of Al and F. Thermogravimetric analysis proves the mineral decomposes at 485 °C with a mass loss of 7.6% compared with the theoretical mass loss of 7.7%. A strong Raman band at 852 cm-1 is assigned to the SiO stretching vibration of the SiO3(OH) units. Two Raman bands at 914 and 953 cm-1 are attributed to the antisymmetric vibrations. Intense prominent peaks observed at 3487, 3502, 3509, 3521 and 3547 cm-1 are assigned to the OH stretching vibration of the SiO3(OH) units. The observation of multiple OH bands supports the concept of the non-equivalence of the OH units. Vibrational spectroscopy enables a detailed assessment of the molecular structure of poldervaartite.

  14. Structural basis for the differential effects of CaBP1 and calmodulin on CaV1.2 calcium-dependent inactivation

    Science.gov (United States)

    Findeisen, Felix; Minor, Daniel L.

    2010-01-01

    Calcium-binding protein 1 (CaBP1), a calmodulin (CaM) homolog, endows certain voltage-gated calcium channels (CaVs) with unusual properties. CaBP1 inhibits CaV1.2 calcium-dependent inactivation (CDI) and introduces calcium-dependent facilitation (CDF). Here, we show that the ability of CaBP1 to inhibit CaV1.2 CDI and induce CDF arises from interaction between the CaBP1 N-lobe and interlobe linker residue Glu94. Unlike CaM, where functional EF hands are essential for channel modulation, CDI inhibition does not require functional CaBP1 EF-hands. Furthermore, CaBP1-mediated CDF has different molecular requirements than CaM-mediated CDF. Overall, the data show that CaBP1 comprises two structural modules having separate functions: similar to CaM, the CaBP1 C-lobe serves as a high-affinity anchor that binds the CaV1.2 IQ domain at a site that overlaps with the Ca2+/CaM C-lobe site, whereas the N-lobe/linker module houses the elements required for channel modulation. Discovery of this division provides the framework for understanding how CaBP1 regulates CaVs. PMID:21134641

  15. Structural basis for the differential effects of CaBP1 and calmodulin on Ca(V)1.2 calcium-dependent inactivation.

    Science.gov (United States)

    Findeisen, Felix; Minor, Daniel L

    2010-12-08

    Calcium-binding protein 1 (CaBP1), a calmodulin (CaM) homolog, endows certain voltage-gated calcium channels (Ca(V)s) with unusual properties. CaBP1 inhibits Ca(V)1.2 calcium-dependent inactivation (CDI) and introduces calcium-dependent facilitation (CDF). Here, we show that the ability of CaBP1 to inhibit Ca(V)1.2 CDI and induce CDF arises from interaction between the CaBP1 N-lobe and interlobe linker residue Glu94. Unlike CaM, where functional EF hands are essential for channel modulation, CDI inhibition does not require functional CaBP1 EF hands. Furthermore, CaBP1-mediated CDF has different molecular requirements than CaM-mediated CDF. Overall, the data show that CaBP1 comprises two structural modules having separate functions: similar to CaM, the CaBP1 C-lobe serves as a high-affinity anchor that binds the Ca(V)1.2 IQ domain at a site that overlaps with the Ca²+/CaM C-lobe site, whereas the N-lobe/linker module houses the elements required for channel modulation. Discovery of this division provides the framework for understanding how CaBP1 regulates Ca(V)s. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes.

    Directory of Open Access Journals (Sweden)

    Cristina I López Sanjurjo

    Full Text Available Inositol 1,4,5-trisphosphate (IP3 evokes release of Ca2+ from the endoplasmic reticulum (ER, but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.

  17. Rapid recycling of Ca2+ between IP3-sensitive stores and lysosomes.

    Science.gov (United States)

    López Sanjurjo, Cristina I; Tovey, Stephen C; Taylor, Colin W

    2014-01-01

    Inositol 1,4,5-trisphosphate (IP3) evokes release of Ca2+ from the endoplasmic reticulum (ER), but the resulting Ca2+ signals are shaped by interactions with additional intracellular organelles. Bafilomycin A1, which prevents lysosomal Ca2+ uptake by inhibiting H+ pumping into lysosomes, increased the amplitude of the initial Ca2+ signals evoked by carbachol in human embryonic kidney (HEK) cells. Carbachol alone and carbachol in combination with parathyroid hormone (PTH) evoke Ca2+ release from distinct IP3-sensitive Ca2+ stores in HEK cells stably expressing human type 1 PTH receptors. Bafilomycin A1 similarly exaggerated the Ca2+ signals evoked by carbachol or carbachol with PTH, indicating that Ca2+ released from distinct IP3-sensitive Ca2+ stores is sequestered by lysosomes. The Ca2+ signals resulting from store-operated Ca2+ entry, whether evoked by thapsigargin or carbachol, were unaffected by bafilomycin A1. Using Gd3+ (1 mM) to inhibit both Ca2+ entry and Ca2+ extrusion, HEK cells were repetitively stimulated with carbachol to assess the effectiveness of Ca2+ recycling to the ER after IP3-evoked Ca2+ release. Blocking lysosomal Ca2+ uptake with bafilomycin A1 increased the amplitude of each carbachol-evoked Ca2+ signal without affecting the rate of Ca2+ recycling to the ER. This suggests that Ca2+ accumulated by lysosomes is rapidly returned to the ER. We conclude that lysosomes rapidly, reversibly and selectively accumulate the Ca2+ released by IP3 receptors residing within distinct Ca2+ stores, but not the Ca2+ entering cells via receptor-regulated, store-operated Ca2+ entry pathways.

  18. Burst activity and ultrafast activation kinetics of CaV1.3 Ca²⁺ channels support presynaptic activity in adult gerbil hair cell ribbon synapses.

    Science.gov (United States)

    Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Knipper, Marlies; Holley, Matthew C; Magistretti, Jacopo; Masetto, Sergio; Marcotti, Walter

    2013-08-15

    Auditory information transfer to afferent neurons relies on precise triggering of neurotransmitter release at the inner hair cell (IHC) ribbon synapses by Ca²⁺ entry through CaV1.3 Ca²⁺ channels. Despite the crucial role of CaV1.3 Ca²⁺ channels in governing synaptic vesicle fusion, their elementary properties in adult mammals remain unknown. Using near-physiological recording conditions we investigated Ca²⁺ channel activity in adult gerbil IHCs. We found that Ca²⁺ channels are partially active at the IHC resting membrane potential (-60 mV). At -20 mV, the large majority (>70%) of Ca²⁺ channel first openings occurred with an estimated delay of about 50 μs in physiological conditions, with a mean open time of 0.5 ms. Similar to other ribbon synapses, Ca²⁺ channels in IHCs showed a low mean open probability (0.21 at -20 mV), but this increased significantly (up to 0.91) when Ca²⁺ channel activity switched to a bursting modality. We propose that IHC Ca²⁺ channels are sufficiently rapid to transmit fast signals of sound onset and support phase-locking. Short-latency Ca²⁺ channel opening coupled to multivesicular release would ensure precise and reliable signal transmission at the IHC ribbon synapse.

  19. Ca 3d unoccupied states in Bi2Sr2CaCu2O8 investigated by Ca L2,3 x-ray-absorption near-edge structure

    International Nuclear Information System (INIS)

    Borg, A.; King, P.L.; Pianetta, P.; Lindau, I.; Mitzi, D.B.; Kapitulnik, A.; Soldatov, A.V.; Della Longa, S.; Bianconi, A.

    1992-01-01

    The high-resolution Ca L 2,3 x-ray-absorption near-edge-structure (XANES) spectrum of a Bi 2 Sr 2 CaCu 2 O 8 single crystal has been measured by use of a magnetic-projection x-ray microscope probing a surface area of 200x200 μm 2 . The Ca L 2,3 XANES spectrum is analyzed by performing a multiple-scattering XANES calculation in real space and comparing the results with the spectrum of CaF 2 . Good agreement between the calculated and experimental crystal-field splitting Δ f of the Ca 3d final states is found and the splitting is shown to be smaller by 0.5 eV than in the initial state. The Ca 3d partial density of states is found to be close to the Fermi level in the initial state. The Ca-O(in plane) distance is shown to be a critical parameter associated with the shift of the Ca 3d states relative to the Fermi level; in particular, we have studied the effect of the out-of-plane dimpling mode of the in-plane oxygen atoms O(in plane) that will move the Ca 3d states on or off the Fermi level. This mode can therefore play a role in modulating the charge transfer between the two CuO 2 planes separated by the Ca ions

  20. Ca 3d unoccupied states in Bi2Sr2CaCu2O8 investigated by Ca L2,3 x-ray-absorption near-edge structure

    Energy Technology Data Exchange (ETDEWEB)

    Borg, A; King, P L; Pianetta, P; Lindau, I; Mitzi, D B

    1992-01-01

    The high-resolution Ca L(2,3) x-ray-absorption near-edge-structure (XANES) spectrum of a Bi2Sr2CaCu2O8 single crystal has been measured by use of a magnetic-projection x-ray microscope probing a surface area of 200x200 micrometers square. The Ca L(2,3) XANES spectrum is analyzed by performing a multiple-scattering XANES calculation in real space and comparing the results with the spectrum of CaF2. Good agreement between the calculated and experimental crystal-field splitting Delta f of the Ca 3d final states is found and the splitting is shown to be smaller by 0.5 eV than in the initial state. The Ca 3d partial density of states is found to be close to the Fermi level in the initial state. The Ca-O (in plane) distance is shown to be a critical parameter associated with the shift of the Ca 3d states relative to the Fermi level; in particular, the authors have studied the effect of the out-of-plane dimpling mode of the in-plane oxygen atoms O(in plane) that will move the Ca 3d states on or off the Fermi level. This mode can therefore play a role in modulating the charge transfer between the two CuO2 planes separated by the Ca ions.

  1. A process analysis of the CA3 subregion of the hippocampus

    Directory of Open Access Journals (Sweden)

    Raymond PIERRE Kesner

    2013-05-01

    Full Text Available AbstractFrom a behavioral perspective the CA3a,b subregion of the hippocampus plays an important role in the encoding of new spatial information within short-term memory with a duration of seconds and minutes. This can easily be observed in tasks that require rapid encoding, novelty detection, 1-trial short- term or working memory, and 1-trial cued recall primarily for spatial information. These are tasks that have been assumed to reflect the operations of episodic memory and require interactions between CA3a,b and the dentate gyrus via mossy fiber inputs into the CA3a,b. The CA3a,b is also important for encoding of spatial information requiring the acquisition of arbitrary and relational associations. All these tasks are assumed to operate within an autoassociative network function of the CA3 region. The CA3a,b also supports retrieval of short-term memory information based on a spatial pattern completion process. Based on afferent inputs into CA3a,b from the dentate gyrus (DG via mossy fibers and afferents from the entorhinal cortex into CA3a,b as well as reciprocal connections with the septum, CA3a,b can bias the process of encoding utilizing the operation of spatial pattern separation and the process of retrieval utilizing the operation of pattern completion. The CA3a,b also supports sequential processing of information in cooperation with CA1 based on the Schaffer collateral output from CA3a,b to CA1. The CA3c function is in part based on modulation of the DG in supporting pattern separation processes.

  2. Behavior-driven arc expression is reduced in all ventral hippocampal subfields compared to CA1, CA3, and dentate gyrus in rat dorsal hippocampus.

    Science.gov (United States)

    Chawla, M K; Sutherland, V L; Olson, K; McNaughton, B L; Barnes, C A

    2018-02-01

    Anatomical connectivity and lesion studies reveal distinct functional heterogeneity along the dorsal-ventral axis of the hippocampus. The immediate early gene Arc is known to be involved in neural plasticity and memory and can be used as a marker for cell activity that occurs, for example, when hippocampal place cells fire. We report here, that Arc is expressed in a greater proportion of cells in dorsal CA1, CA3, and dentate gyrus (DG), following spatial behavioral experiences compared to ventral hippocampal subregions (dorsal CA1 = 33%; ventral CA1 = 13%; dorsal CA3 = 23%; ventral CA3 = 8%; and dorsal DG = 2.5%; ventral DG = 1.2%). The technique used here to obtain estimates of numbers of behavior-driven cells across the dorsal-ventral axis, however, corresponds quite well with samples from available single unit recording studies. Several explanations for the two- to-threefold reduction in spatial behavior-driven cell activity in the ventral hippocampus can be offered. These include anatomical connectivity differences, differential gain of the self-motion signals that appear to alter the scale of place fields and the proportion of active cells, and possibly variations in the neuronal responses to non-spatial information within the hippocampus along its dorso-ventral axis. © 2017 Wiley Periodicals, Inc.

  3. Formation process of micro arc oxidation coatings obtained in a sodium phytate containing solution with and without CaCO{sub 3} on binary Mg-1.0Ca alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.F. [School of Material and Electromechanics, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Zhang, Y.Q. [Zhejiang DunAn Light Alloy Technology CO,.LTD, Zhuji 311835 (China); Hunan University of Science and Technology, Xiangtan 411201 (China); Zhang, S.F.; Qu, B. [School of Material and Electromechanics, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Guo, S.B. [Hunan University of Science and Technology, Xiangtan 411201 (China); Xiang, J.H., E-mail: xiangjunhuai@163.com [School of Material and Electromechanics, Jiangxi Science and Technology Normal University, Nanchang 330013 (China)

    2015-01-15

    Highlights: • Compared to the Mg phase, the area of Mg{sub 2}Ca phase is much smaller. • The coatings are preferentially developed on the area adjacent to Mg{sub 2}Ca phase. • During MAO process, some sodium phytate molecules are hydrolyzed. • Anodic coatings are developed from uneven to uniform. - Abstract: Micro arc oxidation (MAO) is an effective method to improve the corrosion resistance of magnesium alloys. In order to reveal the influence of alloying element Ca and CaCO{sub 3} electrolyte on the formation process and chemical compositions of MAO coatings on binary Mg-1.0Ca alloy, anodic coatings after different anodizing times were prepared on binary Mg-1.0Ca alloy in a base solution containing 3 g/L sodium hydroxide and 15 g/L sodium phytate with and without addition of CaCO{sub 3}. The coating formation was studied by using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results show that Mg-1.0Ca alloy is composed of two phases, the Mg phase and Mg{sub 2}Ca phase. After treating for 5 s, the coating began to develop and was preferentially formed on the area nearby Mg{sub 2}Ca phase, which may be resulted from the intrinsic electronegative potential of the Mg phase than that of Mg{sub 2}Ca phase. Anodic coatings unevenly covered the total surface after 20 s. After 80 s, the coatings were uniformly developed on Mg-1.0Ca alloy with micro pores. During MAO process, some sodium phytate molecules are hydrolyzed into inorganic phosphate. CaCO{sub 3} has minor influence on the calcium content of the obtained MAO coatings.

  4. Formation of ternary CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) complexes under neutral to weakly alkaline conditions.

    Science.gov (United States)

    Lee, Jun-Yeop; Yun, Jong-Il

    2013-07-21

    The chemical behavior of ternary Ca-UO2-CO3 complexes was investigated by using time-resolved laser fluorescence spectroscopy (TRLFS) in combination with EDTA complexation at pH 7-9. A novel TRLFS revealed two distinct fluorescence lifetimes of 12.7 ± 0.2 ns and 29.2 ± 0.4 ns for uranyl complexes which were formed increasingly dependent upon the calcium ion concentration, even though nearly indistinguishable fluorescence peak shapes and positions were measured for both Ca-UO2-CO3 complexes. For identifying the stoichiometric number of complexed calcium ions, slope analysis in terms of relative fluorescence intensity versus calcium concentration was employed in a combination with the complexation reaction of CaEDTA(2-) by adding EDTA. The formation of CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) was identified under given conditions and their formation constants were determined at I = 0.1 M Na/HClO4 medium, and extrapolated to infinitely dilute solution using specific ion interaction theory (SIT). As a result, the formation constants for CaUO2(CO3)3(2-) and Ca2UO2(CO3)3(aq) were found to be log β113(0) = 27.27 ± 0.14 and log β213(0) = 29.81 ± 0.19, respectively, providing that the ternary Ca-UO2-CO3 complexes were predominant uranium(vi) species at neutral to weakly alkaline pH in the presence of Ca(2+) and CO3(2-) ions.

  5. Menstrual Cycle Dependent Variability for Serum Tumor Markers CEA, AFP, CA 19-9, CA 125 and CA 15-3 in Healthy Women

    Directory of Open Access Journals (Sweden)

    Ayşe Binnur Erbağci

    1999-01-01

    Full Text Available Information on menstrual cycle dependent variation of tumor markers in healthy women is a subject of diagnostic efficiency and has an impact in elucidating the normal function of these markers. In this study midfollicular and midluteal concentrations of serum CEA, AFP, CA 19-9, CA 125, CA 15-3 and their relations with LH, FSH, prolactin, estradiol and progesterone were evaluated during ovulatory cycles in a group of 23 healthy female individuals. Samples were collected on the 7th and 21st day of the same menstrual cycle. Tumor marker and hormone concentrations were determined with chemiluminescence or electrochemiluminescence EIA methods. A significant phase-dependent difference was observed for CA 15-3, midluteal concentrations (mean ± SEM; 26.33 ± 1.56 U/ml higher than the midfollicular (mean ± SEM; 19.27 ± 1.49 U/ml concentrations (p < 0.001. But an obvious difference for other tumor markers investigated did not exist. Significant correlations of follicular and luteal CA 125 levels with body mass index of the subjects were observed (r:0.52, p < 0.05 and r:0.57, p < 0.005, respectively.

  6. Long term potentiation, but not depression, in interlamellar hippocampus CA1.

    Science.gov (United States)

    Sun, Duk-Gyu; Kang, Hyeri; Tetteh, Hannah; Su, Junfeng; Lee, Jihwan; Park, Sung-Won; He, Jufang; Jo, Jihoon; Yang, Sungchil; Yang, Sunggu

    2018-03-26

    Synaptic plasticity in the lamellar CA3 to CA1 circuitry has been extensively studied while interlamellar CA1 to CA1 connections have not yet received much attention. One of our earlier studies demonstrated that axons of CA1 pyramidal neurons project to neighboring CA1 neurons, implicating information transfer along a longitudinal interlamellar network. Still, it remains unclear whether long-term synaptic plasticity is present within this longitudinal CA1 network. Here, we investigate long-term synaptic plasticity between CA1 pyramidal cells, using in vitro and in vivo extracellular recordings and 3D holography glutamate uncaging. We found that the CA1-CA1 network exhibits NMDA receptor-dependent long-term potentiation (LTP) without direction or layer selectivity. By contrast, we find no significant long-term depression (LTD) under various LTD induction protocols. These results implicate unique synaptic properties in the longitudinal projection suggesting that the interlamellar CA1 network could be a promising structure for hippocampus-related information processing and brain diseases.

  7. Removal of area CA3 from hippocampal slices induces postsynaptic plasticity at Schaffer collateral synapses that normalizes CA1 pyramidal cell discharge.

    Science.gov (United States)

    Dumas, Theodore C; Uttaro, Michael R; Barriga, Carolina; Brinkley, Tiffany; Halavi, Maryam; Wright, Susan N; Ferrante, Michele; Evans, Rebekah C; Hawes, Sarah L; Sanders, Erin M

    2018-05-05

    Neural networks that undergo acute insults display remarkable reorganization. This injury related plasticity is thought to permit recovery of function in the face of damage that cannot be reversed. Previously, an increase in the transmission strength at Schaffer collateral to CA1 pyramidal cell synapses was observed after long-term activity reduction in organotypic hippocampal slices. Here we report that, following acute preparation of adult rat hippocampal slices and surgical removal of area CA3, input to area CA1 was reduced and Schaffer collateral synapses underwent functional strengthening. This increase in synaptic strength was limited to Schaffer collateral inputs (no alteration to temporoammonic synapses) and acted to normalize postsynaptic discharge, supporting a homeostatic or compensatory response. Short-term plasticity was not altered, but an increase in immunohistochemical labeling of GluA1 subunits was observed in the stratum radiatum (but not stratum moleculare), suggesting increased numbers of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors and a postsynaptic locus of expression. Combined, these data support the idea that, in response to the reduction in presynaptic activity caused by removal of area CA3, Schaffer collateral synapses undergo a relatively rapid increase in functional efficacy likely supported by insertion of more AMPARs, which maintains postsynaptic excitability in CA1 pyramidal neurons. This novel fast compensatory plasticity exhibits properties that would allow it to maintain optimal network activity levels in the hippocampus, a brain structure lauded for its ongoing experience-dependent malleability. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Oxygen chain disorder and compensation by Ca in Y(1-2-3) cuprates

    International Nuclear Information System (INIS)

    Suryanarayanan, R.; Ouhammou, L.; Das, A.; Leelaprute, S.

    1994-01-01

    Several M dopants such as Al, Fe, and Co at the Cu site destroy the superconductivity of YBa 2 Cu 3 O 6+z . However, superconductivity is restored by substituting Ca at the Y site. Arguments are developed to show that the oxygen chain disorder is not the only cause for destroying the superconductivity. A universal relation seems to exist between the net hole density as a result of Ca substitution and Tc. To stabilize the perovskite structure of YSr 2 Cu 3 O 6+z , it is necessary to substitute Cu by certain elements. Examples are given on Ti and Re substitution. Again, Ca cosubstitution increases Tc. Further, the irreversibility line is enhanced by Ca, indicating improved pinning in these materials in spite of the oxygen disorder. 16 refs., 4 figs., 1 tab

  9. CaCO3-III and CaCO3-VI, high-pressure polymorphs of calcite: Possible host structures for carbon in the Earth's mantle

    Science.gov (United States)

    Merlini, M.; Hanfland, M.; Crichton, W. A.

    2012-06-01

    Calcite, CaCO3, undergoes several high pressure phase transitions. We report here the crystal structure determination of the CaCO3-III and CaCO3-VI high-pressure polymorphs obtained by single-crystal synchrotron X-ray diffraction. This new technical development at synchrotron beamlines currently affords the possibility of collecting single-crystal data suitable for structure determination in-situ at non-ambient conditions, even after multiphase transitions. CaCO3-III, observed in the pressure range 2.5-15 GPa, is triclinic, and it presents two closely related structural modifications, one, CaCO3-III, with 50 atoms in the unit cell [a=6.281(1) Å, b=7.507(2) Å, c=12.516(3) Å, α=93.76(2)°, β=98.95(2)°, γ=106.49(2)°, V=555.26(20) Å3 at 2.8 GPa], the second, CaCO3-IIIb, with 20 atoms [a=6.144(3) Å, b=6.3715(14) Å, c=6.3759(15) Å, α= 93.84(2)°, β=107.34(3)°, γ=107.16(3)°, V=224.33(13) Å3 at 3.1 GPa]. Different pressure-time experimental paths can stabilise one or the other polymorph. Both structures are characterised by the presence of non-coplanar CO3 groups. The densities of CaCO3-III (2.99 g/cm3 at 2.8 GPa) and CaCO3-IIIb (2.96 g/cm3 at 3.1 GPa) are lower than aragonite, in agreement with the currently accepted view of aragonite as the thermodynamically stable Ca-carbonate phase at these pressures. The presence of different cation sites, with variable volume and coordination number (7-9), suggests however that these structures have the potential to accommodate cations with different sizes without introducing major structural strain. Indeed, this structure can be adopted by natural Ca-rich carbonates, which often exhibit compositions deviating from pure calcite. Mg-calcites are found both in nature (Frezzotti et al., 2011) and in experimental syntheses at conditions corresponding to deep subduction environments (Poli et al., 2009). At these conditions, the low pressure rhombohedral calcite structure is most unlikely to be stable, and, at the same

  10. PGC-1α accelerates cytosolic Ca2+ clearance without disturbing Ca2+ homeostasis in cardiac myocytes

    International Nuclear Information System (INIS)

    Chen, Min; Wang, Yanru; Qu, Aijuan

    2010-01-01

    Energy metabolism and Ca 2+ handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1α in cardiac Ca 2+ signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1α via adenoviral transduction. Our data shows that overexpressing PGC-1α improved myocyte contractility without increasing the amplitude of Ca 2+ transients, suggesting that myofilament sensitivity to Ca 2+ increased. Interestingly, the decay kinetics of global Ca 2+ transients and Ca 2+ waves accelerated in PGC-1α-expressing cells, but the decay rate of caffeine-elicited Ca 2+ transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca 2+ -ATPase (SERCA2a), but not Na + /Ca 2+ exchange (NCX) contribute to PGC-1α-induced cytosolic Ca 2+ clearance. Furthermore, PGC-1α induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1α did not disturb cardiac Ca 2+ homeostasis, because SR Ca 2+ load and the propensity for Ca 2+ waves remained unchanged. These data suggest that PGC-1α can ameliorate cardiac Ca 2+ cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1α-calcium handing pathway sheds new light on the role of PGC-1α in the therapy of cardiac diseases.

  11. Role of Caspase-3 Cleaved IP3R1 on Ca2+ Homeostasis and Developmental Competence of Mouse Oocytes and Eggs

    Science.gov (United States)

    Zhang, Nan; Fissore, Rafael. A.

    2014-01-01

    Apoptosis in most cell types is accompanied by altered Ca2+ homeostasis. During apoptosis, caspase-3 mediated cleavage of the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) generates a 95-kDa C-terminal fragment (C-IP3R1), which represents the channel domain of the receptor. Aged mouse eggs display abnormal Ca2+ homeostasis and express C-IP3R1, although whether or not C-IP3R1 expression contributes to Ca2+ misregulation or a decrease in developmental competency is unknown. We sought to answer these questions by injecting in mouse oocytes and eggs cRNAs encoding CIP3R1. We found that: 1) expression of C-IP3R1 in eggs lowered the Ca2+ content of the endoplasmic reticulum (ER), although, as C-IP3R1 is quickly degraded at this stage, its expression did not impair pre-implantation embryo development; 2) expression of CIP3R1 in eggs enhanced fragmentation associated with aging; 3) endogenous IP3R1 is required for aging associated apoptosis, as its down-regulation prevented fragmentation, and expression of C-IP3R1 in eggs with downregulated IP3R1 partly restored fragmentation; 4) C-IP3R1 expression in GV oocytes resulted in persistent levels of protein, which abolished the increase in the ER releasable Ca2+ pool that occurs during maturation, undermined the Ca2+ oscillatory ability of matured eggs and their activation potential. Collectively, this study supports a role for IP3R1 and C-IP3R1 in regulating Ca2+ homeostasis and the ER Ca2+ content during oocyte maturation. Nevertheless, the role of C-IP3R1 on Ca2+ homeostasis in aged eggs seems minor, as in MII eggs the majority of endogenous IP3R1 remains intact and C-IP3R1 undergoes rapid turnover. PMID:24692207

  12. crdi.ca

    International Development Research Centre (IDRC) Digital Library (Canada)

    et des enfants d'Afrique. INITIATIVE CONCERTÉE. Innovation pour la santé des mères et des enfants d'Afrique. Centre de recherches pour le développement international. CP Box 8500 Ottawa ON Canada K1G 3H9. Téléphone : +1 613 236 6163 • Télécopieur : +1 613 657 7749 ismea@crdi.ca | www.crdi.ca/ismea crdi.ca.

  13. Close Association of Carbonic Anhydrase (CA2a and CA15a), Na+/H+ Exchanger (Nhe3b), and Ammonia Transporter Rhcg1 in Zebrafish Ionocytes Responsible for Na+ Uptake

    Science.gov (United States)

    Ito, Yusuke; Kobayashi, Sayako; Nakamura, Nobuhiro; Miyagi, Hisako; Esaki, Masahiro; Hoshijima, Kazuyuki; Hirose, Shigehisa

    2013-01-01

    Freshwater (FW) fishes actively absorb salt from their environment to tolerate low salinities. We previously reported that vacuolar-type H+-ATPase/mitochondrion-rich cells (H-MRCs) on the skin epithelium of zebrafish larvae (Danio rerio) are primary sites for Na+ uptake. In this study, in an attempt to clarify the mechanism for the Na+ uptake, we performed a systematic analysis of gene expression patterns of zebrafish carbonic anhydrase (CA) isoforms and found that, of 12 CA isoforms, CA2a and CA15a are highly expressed in H-MRCs at larval stages. The ca2a and ca15a mRNA expression were salinity-dependent; they were upregulated in 0.03 mM Na+ water whereas ca15a but not ca2a was down-regulated in 70 mM Na+ water. Immunohistochemistry demonstrated cytoplasmic distribution of CA2a and apical membrane localization of CA15a. Furthermore, cell surface immunofluorescence staining revealed external surface localization of CA15a. Depletion of either CA2a or CA15a expression by Morpholino antisense oligonucleotides resulted in a significant decrease in Na+ accumulation in H-MRCs. An in situ proximity ligation assay demonstrated a very close association of CA2a, CA15a, Na+/H+ exchanger 3b (Nhe3b), and Rhcg1 ammonia transporter in H-MRC. Our findings suggest that CA2a, CA15a, and Rhcg1 play a key role in Na+uptake under FW conditions by forming a transport metabolon with Nhe3b. PMID:23565095

  14. Semiconductor-metal transition in CaMO3-CaTiO2 (M-Ru,Ir) systems

    International Nuclear Information System (INIS)

    Lazarev, V.B.; Shaplygin, I.S.

    1982-01-01

    Properties of CaRusub(x)Tisub(1-x)Osub(3) and CaIsub(2x)Tisub(1-x)Osub(3) solid solutions were studied in the whole range of concentrations by the methods of X-ray diffraction, electric conductivity and magnetic susceptibility. It was ascertained that the transition of semiconductor-metal type proceeded in the both families of solid solutions at x approximately 0.77 and 0.85 respectively and was accompanied by the change of structural type of solid solutions

  15. Ca isotopes in refractory inclusions

    International Nuclear Information System (INIS)

    Niederer, F.R.; Papanastassiou, D.A.

    1984-01-01

    We report measurements of the absolute isotope abundance of Ca in Ca-Al-rich inclusions from the Allende and Leoville meteorites. Improved high precision measurements are reported also for 46 Ca. We find that nonlinear isotope effects in Ca are extremely rare in these inclusions. The absence of nonlinear effects in Ca, except for the effects in FUN inclusions, is in sharp contrast to the endemic effects in Ti. One fine-grained inclusion shows an excess of 46 Ca of (7 +- 1) per mille, which is consistent with addition of only 46 Ca or of an exotic (*) component with 46 Ca* approx. 48 Ca*. FUN inclusion EK-1-4-1 shows a small 46 Ca excess of (3.3 +- 1.0) per mille; this confirms that the exotic Ca components in EK-1-4-1 were even more deficient in 46 Ca relative to 48 Ca than is the case for normal Ca. The Ca in the Ca-Al-rich inclusions shows mass dependent isotope fractionation effects which have a range from -3.8 to +6.7 per mille per mass unit difference. This range is a factor of 20 wider than the range previously established for bulk meteorites and for terrestrial and lunar samples. Ca and Mg isotope fractionation effects in the Ca-Al-rich inclusions are common and attributed to kinetic isotope effects. (author)

  16. Local Structure of Mn in (La1-xHox)2/3Ca1/3MnO3 Studied by X-ray Absorption Fine Structure

    International Nuclear Information System (INIS)

    Pietnoczka, A.; Bacewicz, R.; Antonowicz, J.; Zalewski, W.; Pekala, M.; Drozd, V.; Fagnard, J.F.; Vanderbemden, P.

    2010-01-01

    Results of X-ray absorption fine structure measurements in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 with 0.15 3 is doped with a divalent element such as Ca 2+ , substituting for La 3+ , holes are induced in the filled Mn d orbitals. This leads to a strong ferromagnetic coupling between Mn sites. Ca ions in La 1-x Ca x MnO 3 introduce a distortion of the crystal lattice and mixed valence Mn ions (Mn 3+ and Mn 4+ ). On the other hand, in manganites (La 1-x Ho x ) 2/3 Ca 1/3 MnO 3 the substitution of La for Ho causes a lattice distortion and induces a disorder, which reduces a magnetic interaction. The ferromagnetic transition temperature and conductivity decrease very quickly with increasing x. The magnetic and transport properties of compounds depend on the local atomic structure around Mn ions. The information on the bond lengths and Debye-Waller factor are obtained from the extended X-ray absorption fine structure (EXAFS) data analysis. The charge state of Mn is determined from the position of the absorption edge in X-ray absorption near edge structure (XANES) data. XAFS results are in good agreement with magnetic characteristics of the studied materials. (authors)

  17. Probing the electronic properties of ternary AnM3n−1B2n (n = 1: A = Ca, Sr; M = Rh, Ir and n = 3: A = Ca, Sr; M = Rh phases: observation of superconductivity

    Directory of Open Access Journals (Sweden)

    Hiroyuki Takeya, Mohammed ElMassalami, Luis A Terrazos, Raul E Rapp, Rodrigo B Capaz, Hiroki Fujii, Yoshihiko Takano, Mathias Doerr and Sergey A Granovsky

    2013-01-01

    Full Text Available We follow the evolution of the electronic properties of the titled homologous series when n as well as the atomic type of A and M are varied where for n = 1, A = Ca, Sr and M = Rh, Ir while for n = 3, A = Ca, Sr and M = Rh. The crystal structure of n = 1 members is known to be CaRh2B2-type (Fddd, while that of n = 3 is Ca3Rh8B6-type (Fmmm; the latter can be visualized as a stacking of structural fragments from AM3B2 (P6/mmm and AM2B2. The metallic properties of the n = 1 and 3 members are distinctly different: on the one hand, the n = 1 members are characterized by a linear coefficient of the electronic specific heat γ ≈ 3 mJ mol−1 K−2, a Debye temperature θD ≈ 300 K, a normal conductivity down to 2 K and a relatively strong linear magnetoresistivity for fields up to 150 kOe. The n = 3 family, on the other hand, exhibits γ ≈ 18 mJ mol−1 K−2, θD ≈ 330 K, a weak linear magnetoresistivity and an onset of superconductivity (for Ca3Rh8B6, Tc = 4.0 K and Hc2 = 14.5 kOe, while for Sr3Rh8 B6, Tc = 3.4 K and Hc2 ≈ 4.0 kOe. These remarkable differences are consistent with the findings of the electronic band structures and density of state (DOS calculations. In particular, satisfactory agreement between the measured and calculated γ was obtained. Furthermore, the Fermi level, EF, of Ca3Rh8B6 lies at almost the top of a pronounced local DOS peak, while that of CaRh2B2 lies at a local valley: this is the main reason behind the differences between the, e.g., superconducting properties. Finally, although all atoms contribute to the DOS at EF, the contribution of the Rh atoms is the strongest.

  18. Probing the electronic properties of ternary AnM3n−1B2n (n = 1: A = Ca, Sr; M = Rh, Ir and n = 3: A = Ca, Sr; M = Rh) phases: observation of superconductivity

    Science.gov (United States)

    Takeya, Hiroyuki; ElMassalami, Mohammed; Terrazos, Luis A; Rapp, Raul E; Capaz, Rodrigo B; Fujii, Hiroki; Takano, Yoshihiko; Doerr, Mathias; Granovsky, Sergey A

    2013-01-01

    We follow the evolution of the electronic properties of the titled homologous series when n as well as the atomic type of A and M are varied where for n = 1, A = Ca, Sr and M = Rh, Ir while for n = 3, A = Ca, Sr and M = Rh. The crystal structure of n = 1 members is known to be CaRh2B2-type (Fddd), while that of n = 3 is Ca3Rh8B6-type (Fmmm); the latter can be visualized as a stacking of structural fragments from AM3B2 (P6/mmm) and AM2B2. The metallic properties of the n = 1 and 3 members are distinctly different: on the one hand, the n = 1 members are characterized by a linear coefficient of the electronic specific heat γ ≈ 3 mJ mol−1 K−2, a Debye temperature θD ≈ 300 K, a normal conductivity down to 2 K and a relatively strong linear magnetoresistivity for fields up to 150 kOe. The n = 3 family, on the other hand, exhibits γ ≈ 18 mJ mol−1 K−2, θD ≈ 330 K, a weak linear magnetoresistivity and an onset of superconductivity (for Ca3Rh8B6, Tc = 4.0 K and Hc2 = 14.5 kOe, while for Sr3Rh8 B6, Tc = 3.4 K and Hc2 ≈ 4.0 kOe). These remarkable differences are consistent with the findings of the electronic band structures and density of state (DOS) calculations. In particular, satisfactory agreement between the measured and calculated γ was obtained. Furthermore, the Fermi level, EF, of Ca3Rh8B6 lies at almost the top of a pronounced local DOS peak, while that of CaRh2B2 lies at a local valley: this is the main reason behind the differences between the, e.g., superconducting properties. Finally, although all atoms contribute to the DOS at EF, the contribution of the Rh atoms is the strongest. PMID:27877576

  19. Effect of Nd substitution for Ca on crystal structure, optical and magnetic properties of multiferroic Bi0.9Ca0.1FeO3

    International Nuclear Information System (INIS)

    Quan, Chuye; Ma, Yuhui; Han, Yumin; Tang, Xingxing; Lu, Mengjia; Mao, Weiwei; Zhang, Jian; Yang, Jianping; Li, Xing’ao

    2015-01-01

    Highlights: • Crystal structure of doped samples transform to two phase coexistence. • The crystal size decreased to ∼50 nm after doping. • Ultraviolet absorption peak demonstrates apparent blue shift for doped sample. • The ratio of Fe 2+ increased by merging Nd. • Ca, Nd co-doped can promote the ferromagnetism obviously. - Abstract: Pure and co-doped BiFeO 3 (Ca, Nd) nanoparticles with diameter in the range of 50–250 nm were synthesized through a sol–gel method. X-ray diffraction (XRD) and Raman results show that Bi-site co-doped with Ca, Nd could result in a transition of crystal structure (from single phase rhombohedral (R3c) to two phase coexistence). An apparent blue shift can be observed in the co-doped samples along with a decrease of the direct optical band gap. Moreover, the leakage current was decreased due to the introduction of nonvolatile Ca and Nd at Bi 3+ site. Analysis of MPMS-VSM magnetic hysteresis data reveals a further enhancement in magnetism in the Nd doped Bi 0.9 Ca 0.1 FeO 3, which is further explained by XPS characterization

  20. Synthesis, microstructure and EPR of CaMnO3 and EuxCa1-xMnO3 manganite, obtained by coprecipitation

    International Nuclear Information System (INIS)

    Santiago T, M.; Hernandez C, L.; Legorreta G, F.; Montiel S, H.; Alvarez L, G.; Flores G, M. A.

    2011-01-01

    The synthesis of CaMnO 3 and Eu x Ca 1-x MnO 3 obtained by coprecipitation method is showed. The synthesized samples were characterized by X-ray diffraction and scanning electronic microscopy, the powders showed orthorhombic structure and pnma space group. When it was doped with Europium, their morphology tendency was spherical. Measurements were carried out on electron paramagnetic resonance (EPR) with constant frequency = 9.4 GHz (band X) and dc magnetic field (H dc) 0-0.8 T, measurements were at 300 K and 77 K. EPR spectra showed significant differences between both samples, indicating that the substitution of divalent alkaline earth cations by trivalent rare earth ions, allowing the formation of a mixed valence state of manganese, Mn 3+ and Mn 4+ . A 77 K, the manganite of concentration x = 0.30 had a magnetic ordering, noted by the presence of hysteresis. (Author)

  1. Anti-tumor activity of self-charged (Eu,Ca):WO3 and Eu:CaWO4 nanoparticles

    International Nuclear Information System (INIS)

    Lin, Cao; Cong, Wang; De'An, Pan; Jiexin, Cao; Ping, Che; Volinsky, Alex A.

    2012-01-01

    Non-stoichiometric (Eu,Ca):WO 3 and Eu:CaWO 4 nanoparticles with anti-tumor activity are synthesized in a sol-gel method by adding excessive Eu 3+ and Ca 2+ ions to tungsten oxide crystal structure. Colorimetric assay shows that 10 nm (Eu,Ca):WO 3 and Eu:CaWO 4 nanoparticles can effectively inhibit growth of mammary cancer cells without any harm to normal cells. Nanoparticles are characterized by X-ray diffraction, high resolution transmission electron microscopy and fluorescence optical spectrometry. Nanomaterials, insoluble in synthesized water, have complicated self-charging surfaces that trap mammary cancer cells. Surface self-charging effect is suggested as the inhibition mechanism. (author)

  2. Effects of 45Ca on murine skeletal muscle. 1

    International Nuclear Information System (INIS)

    Asotra, K.; Katoch, S.S.; Krishan, K.; Malhotra, R.K.

    1983-01-01

    Adult Swiss albino mice weighing 16+-1 g were injected with 3.7x10 4 Bq and 7.4x10 4 Bq/g body weight of 45 Ca. Mice of both dose groups were autopsied on days 1, 3, 5, 7, 14 and 28 after 45 Ca administration. Diaphragm and gastrocnemius in the 45 Ca-treated and normal mice were analyzed for quantitation of glycogen as well as bioassay of phosphorylase and phosphohexose isomerase activities. Internal irradiation with the two doses of 45 Ca resulted in glycogen accumulation in both the muscles. 45 Ca-treated diaphragm showed greater radioresponse but a slower recovery than gastrocnemius with respect to glycogen accumulation. A decline in the rates of glycogenolysis and glycolysis indicated by decreased phosphorylase and phosphohexose isomerase activities appeared to be responsible for glycogen accumulation in skeletal muscle on account of 45 Ca treatment. (author)

  3. Fine Tuning of CaV1.3 Ca2+ channel properties in adult inner hair cells positioned in the most sensitive region of the Gerbil Cochlea.

    Directory of Open Access Journals (Sweden)

    Valeria Zampini

    Full Text Available Hearing relies on faithful signal transmission by cochlear inner hair cells (IHCs onto auditory fibres over a wide frequency and intensity range. Exocytosis at IHC ribbon synapses is triggered by Ca(2+ inflow through Ca(V1.3 (L-type Ca(2+ channels. We investigated the macroscopic (whole-cell and elementary (cell-attached properties of Ca(2+ currents in IHCs positioned at the middle turn (frequency ∼ 2 kHz of the adult gerbil cochlea, which is their most sensitive hearing region. Using near physiological recordings conditions (body temperature and a Na(+ based extracellular solution, we found that the macroscopic Ca(2+ current activates and deactivates very rapidly (time constant below 1 ms and inactivates slowly and only partially. Single-channel recordings showed an elementary conductance of 15 pS, a sub-ms latency to first opening, and a very low steady-state open probability (Po: 0.024 in response to 500-ms depolarizing steps at ∼-18 mV. The value of Po was significantly larger (0.06 in the first 40 ms of membrane depolarization, which corresponds to the time when most Ca(2+ channel openings occurred clustered in bursts (mean burst duration: 19 ms. Both the Po and the mean burst duration were smaller than those previously reported in high-frequency basal IHCs. Finally, we found that middle turn IHCs are likely to express about 4 times more Ca(2+ channels per ribbon than basal cells. We propose that middle-turn IHCs finely-tune Ca(V1.3 Ca(2+ channel gating in order to provide reliable information upon timing and intensity of lower-frequency sounds.

  4. Fine Tuning of CaV1.3 Ca2+ channel properties in adult inner hair cells positioned in the most sensitive region of the Gerbil Cochlea.

    Science.gov (United States)

    Zampini, Valeria; Johnson, Stuart L; Franz, Christoph; Knipper, Marlies; Holley, Matthew C; Magistretti, Jacopo; Russo, Giancarlo; Marcotti, Walter; Masetto, Sergio

    2014-01-01

    Hearing relies on faithful signal transmission by cochlear inner hair cells (IHCs) onto auditory fibres over a wide frequency and intensity range. Exocytosis at IHC ribbon synapses is triggered by Ca(2+) inflow through Ca(V)1.3 (L-type) Ca(2+) channels. We investigated the macroscopic (whole-cell) and elementary (cell-attached) properties of Ca(2+) currents in IHCs positioned at the middle turn (frequency ∼ 2 kHz) of the adult gerbil cochlea, which is their most sensitive hearing region. Using near physiological recordings conditions (body temperature and a Na(+) based extracellular solution), we found that the macroscopic Ca(2+) current activates and deactivates very rapidly (time constant below 1 ms) and inactivates slowly and only partially. Single-channel recordings showed an elementary conductance of 15 pS, a sub-ms latency to first opening, and a very low steady-state open probability (Po: 0.024 in response to 500-ms depolarizing steps at ∼-18 mV). The value of Po was significantly larger (0.06) in the first 40 ms of membrane depolarization, which corresponds to the time when most Ca(2+) channel openings occurred clustered in bursts (mean burst duration: 19 ms). Both the Po and the mean burst duration were smaller than those previously reported in high-frequency basal IHCs. Finally, we found that middle turn IHCs are likely to express about 4 times more Ca(2+) channels per ribbon than basal cells. We propose that middle-turn IHCs finely-tune Ca(V)1.3 Ca(2+) channel gating in order to provide reliable information upon timing and intensity of lower-frequency sounds.

  5. Microwave dielectric properties of (Ca0.8Sr0.2)(SnxTi1−x)O3 ceramics

    International Nuclear Information System (INIS)

    Hsu, Cheng-Hsing; Chang, Chia-Hao

    2013-01-01

    Highlights: ► New microwave dielectric properties of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics were investigated. ► A single-phase solid solution containing orthorhombic Pbnm with different Sn contents was formed. ► A significant improvement of Q × f value and τ f were achieved by (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 system. ► Second phases were formed and affected the dielectric properties of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 system. ► Low cost and suitable τ f value of (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 demonstrate a good potential for use in microwave device. -- Abstract: In this paper, we study the behavior of the B-site behavior with the incorporation of Sn 4+ ion in (Ca 0.8 Sr 0.2 )TiO 3 ceramics. An excess of Sn 4+ resulted in the formation of a secondary phase of CaSnO 3 and SrSnO 3 affecting the microwave dielectric properties of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics. The dielectric properties of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics were improved because of the solid solution of Sn 4+ substitution in the B-site. The temperature coefficient of resonant frequency (τ f ) of the (Ca 0.8 Sr 0.2 )(Sn x Ti 1−x )O 3 ceramics also improved with increasing Sn content

  6. A Novel Mutation in Isoform 3 of the Plasma Membrane Ca2+ Pump Impairs Cellular Ca2+ Homeostasis in a Patient with Cerebellar Ataxia and Laminin Subunit 1α Mutations.

    Science.gov (United States)

    Calì, Tito; Lopreiato, Raffaele; Shimony, Joshua; Vineyard, Marisa; Frizzarin, Martina; Zanni, Ginevra; Zanotti, Giuseppe; Brini, Marisa; Shinawi, Marwan; Carafoli, Ernesto

    2015-06-26

    The particular importance of Ca(2+) signaling to neurons demands its precise regulation within their cytoplasm. Isoform 3 of the plasma membrane Ca(2+) ATPase (the PMCA3 pump), which is highly expressed in brain and cerebellum, plays an important role in the regulation of neuronal Ca(2+). A genetic defect of the PMCA3 pump has been described in one family with X-linked congenital cerebellar ataxia. Here we describe a novel mutation in the ATP2B3 gene in a patient with global developmental delay, generalized hypotonia and cerebellar ataxia. The mutation (a R482H replacement) impairs the Ca(2+) ejection function of the pump. It reduces the ability of the pump expressed in model cells to control Ca(2+) transients generated by cell stimulation and impairs its Ca(2+) extrusion function under conditions of low resting cytosolic Ca(2+) as well. In silico analysis of the structural effect of the mutation suggests a reduced stabilization of the portion of the pump surrounding the mutated residue in the Ca(2+)-bound state. The patient also carries two missense mutations in LAMA1, encoding laminin subunit 1α. On the basis of the family pedigree of the patient, the presence of both PMCA3 and laminin subunit 1α mutations appears to be necessary for the development of the disease. Considering the observed defect in cellular Ca(2+) homeostasis and the previous finding that PMCAs act as digenic modulators in Ca(2+)-linked pathologies, the PMCA3 dysfunction along with LAMA1 mutations could act synergistically to cause the neurological phenotype. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  7. A Novel Mutation in Isoform 3 of the Plasma Membrane Ca2+ Pump Impairs Cellular Ca2+ Homeostasis in a Patient with Cerebellar Ataxia and Laminin Subunit 1α Mutations*

    Science.gov (United States)

    Calì, Tito; Lopreiato, Raffaele; Shimony, Joshua; Vineyard, Marisa; Frizzarin, Martina; Zanni, Ginevra; Zanotti, Giuseppe; Brini, Marisa; Shinawi, Marwan; Carafoli, Ernesto

    2015-01-01

    The particular importance of Ca2+ signaling to neurons demands its precise regulation within their cytoplasm. Isoform 3 of the plasma membrane Ca2+ ATPase (the PMCA3 pump), which is highly expressed in brain and cerebellum, plays an important role in the regulation of neuronal Ca2+. A genetic defect of the PMCA3 pump has been described in one family with X-linked congenital cerebellar ataxia. Here we describe a novel mutation in the ATP2B3 gene in a patient with global developmental delay, generalized hypotonia and cerebellar ataxia. The mutation (a R482H replacement) impairs the Ca2+ ejection function of the pump. It reduces the ability of the pump expressed in model cells to control Ca2+ transients generated by cell stimulation and impairs its Ca2+ extrusion function under conditions of low resting cytosolic Ca2+ as well. In silico analysis of the structural effect of the mutation suggests a reduced stabilization of the portion of the pump surrounding the mutated residue in the Ca2+-bound state. The patient also carries two missense mutations in LAMA1, encoding laminin subunit 1α. On the basis of the family pedigree of the patient, the presence of both PMCA3 and laminin subunit 1α mutations appears to be necessary for the development of the disease. Considering the observed defect in cellular Ca2+ homeostasis and the previous finding that PMCAs act as digenic modulators in Ca2+-linked pathologies, the PMCA3 dysfunction along with LAMA1 mutations could act synergistically to cause the neurological phenotype. PMID:25953895

  8. Photoluminescence and thermoluminescence characterization of Eu3+- and Dy3+ -activated Ca3(PO4)2 phosphor

    International Nuclear Information System (INIS)

    Nagpure, I.M.; Saha, Subhajit; Dhoble, S.J.

    2009-01-01

    Rare-earth-doped polycrystalline Ca 3 (PO 4 ) 2 :Eu, Ca 3 (PO 4 ) 2 :Dy and Ca 3 (PO 4 ) 2 :Eu,Dy phosphors prepared by a modified solid-state synthesis has been studied for its X-ray diffraction, thermoluminescence (TL) and photoluminescence (PL) characteristics. The PL emission spectra of the phosphor suggest the presence of Eu 3+ ion in Ca 3 (PO 4 ) 2 :Eu and Dy 3+ ion in Ca 3 (PO 4 ) 2 :Dy lattice sites. The TL glow curve of the Ca 3 (PO 4 ) 2 :Eu compounds has a simple structure with a prominent peak at 228 deg. C, while Ca 3 (PO 4 ) 2 :Dy peaking at 146 and 230 deg. C. TL sensitivity of phosphors are compared with CaSO 4 : Dy and found 1.52 and 1.20 times less in Ca 3 (PO 4 ) 2 :Eu and Ca 3 (PO 4 ) 2 :Dy phosphors, respectively. The Ca 3 (PO 4 ) 2 :Eu,Dy phosphors shows switching behavior under two different excitation wavelengths and enhancement in PL intensity of Dy 3+ ions were reported. The paper discusses the photoluminescence and thermoluminescence behavior of Eu 3+ and Dy 3+ ion in Ca 3 (PO 4 ) 2 hosts, it may be applicable to solid-state lighting as well as thermoluminescence dosimetry applications.

  9. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility.

    Science.gov (United States)

    González-Vega, J Caroline; Walk, Carrie L; Liu, Yanhong; Stein, Hans H

    2014-01-01

    An experiment was conducted to test the hypothesis that the standardised digestibility of Ca in calcium carbonate and Lithothamnium calcareum Ca is not different regardless of the level of dietary Ca, and that phytic acid affects the digestibility of Ca in these two ingredients to the same degree. The objectives were to determine where in the intestinal tract Ca absorption takes place and if there are measurable quantities of basal endogenous Ca fluxes in the stomach, small intestine or large intestine. Diets contained calcium carbonate or L. calcareum Ca as the sole source of Ca, 0% or 1% phytic acid and 0.4% or 0.8% Ca. A Ca-free diet was also formulated and used to measure endogenous fluxes and losses of Ca. Nine growing pigs (initial body weight 23.8 ± 1.3 kg) were cannulated in the duodenum and in the distal ileum, and faecal, ileal and duodenal samples were collected. Duodenal endogenous fluxes of Ca were greater (p calcareum Ca diets, but that was not the case if calcium carbonate was the source of Ca (interaction, p calcareum Ca was greater (p calcareum Ca. In conclusion, under the conditions of this experiment, standardised digestibility of Ca is not affected by the level of phytic acid, but may be affected by dietary Ca level depending on the Ca source. Calcium from calcium carbonate is mostly absorbed before the duodenum, but Ca from L. calcareum Ca is mostly absorbed in the jejunum and ileum.

  10. Pycnometric and Spectroscopic Studies of Red Phosphors Ca{sub (1-1.5x)}{sup 2+} WO{sub 4}:Eu{sub x}{sup 3+} Ca{sub (1}-{sub 2x)}{sup 2+} WO{sub 4}:Eu{sub x}{sup 3+},Na{sub x}{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seonwoog [Silla Univ., Busan (Korea, Republic of)

    2013-09-15

    Red phosphors Ca{sub (1-1.5x)}Eu{sub x}WO{sub 4} and Ca{sub (1-2x)}Eu{sub x}Na{sub x}WO{sub 4} were synthesized with various concentrations x of Eu{sup 3+} ions by using a solid-state reaction method. The crystal structure of the red phosphors were found to be a tetragonal scheelite structure with space group I4{sub 1}/a. X-ray diffraction (XRD) results show the (112) main diffraction peak centered at 2θ = 28.71 .deg., and indicate that there is no basic structural deformation caused by the vacancies V{sub Ca}'' or the Eu{sup 3+} (and Na{sup +}) ions in the host crystals. Densities of Ca{sub (1.1.5x)}Eu{sub x}WO{sub 4} were measured on a (helium) gas pycnometer. Comparative results between the experimental and theoretical densities reveal that Eu{sup 3+} (and Na{sup +}) ions replace the Ca{sup 2+} ions in the host CaWO{sub 4}. Also, the photoluminescence (PL) emission and photoluminescence excitation (PLE) spectra show the optical properties of trivalent Eu{sup 3+} ions, not of divalent Eu{sup 2+}. Raman spectra exhibit that, without showing any difference before and after the doping of activators to the host material CaWO{sub 4}, all the gerade normal modes occur at the identical frequencies with the same shapes and weaker intensities after the substitution. However, the FT-IR spectra show that some of the ungerade normal modes have shifted positions and different shapes, caused by different masses of Eu{sup 3+} ions (or Na{sup +} ions, or V{sub Ca}'' vacancies) from Ca2{sup +}.

  11. Probing the electronic properties of ternary A n M3n-1B2n (n = 1: A = Ca, Sr; M = Rh, Ir and n = 3: A = Ca, Sr; M = Rh) phases: observation of superconductivity.

    Science.gov (United States)

    Takeya, Hiroyuki; ElMassalami, Mohammed; Terrazos, Luis A; Rapp, Raul E; Capaz, Rodrigo B; Fujii, Hiroki; Takano, Yoshihiko; Doerr, Mathias; Granovsky, Sergey A

    2013-06-01

    We follow the evolution of the electronic properties of the titled homologous series when n as well as the atomic type of A and M are varied where for n = 1, A = Ca, Sr and M = Rh, Ir while for n = 3, A = Ca, Sr and M = Rh. The crystal structure of n = 1 members is known to be CaRh 2 B 2 -type ( Fddd ), while that of n = 3 is Ca 3 Rh 8 B 6 -type ( Fmmm ); the latter can be visualized as a stacking of structural fragments from AM 3 B 2 ( P 6/ mmm ) and AM 2 B 2 . The metallic properties of the n = 1 and 3 members are distinctly different: on the one hand, the n = 1 members are characterized by a linear coefficient of the electronic specific heat γ ≈ 3 mJ mol -1 K -2 , a Debye temperature θ D ≈ 300 K, a normal conductivity down to 2 K and a relatively strong linear magnetoresistivity for fields up to 150 kOe. The n = 3 family, on the other hand, exhibits γ ≈ 18 mJ mol -1 K -2 , θ D ≈ 330 K, a weak linear magnetoresistivity and an onset of superconductivity (for Ca 3 Rh 8 B 6 , T c = 4.0 K and H c2 = 14.5 kOe, while for Sr 3 Rh 8 B 6 , T c = 3.4 K and H c2 ≈ 4.0 kOe). These remarkable differences are consistent with the findings of the electronic band structures and density of state (DOS) calculations. In particular, satisfactory agreement between the measured and calculated γ was obtained. Furthermore, the Fermi level, E F , of Ca 3 Rh 8 B 6 lies at almost the top of a pronounced local DOS peak, while that of CaRh 2 B 2 lies at a local valley: this is the main reason behind the differences between the, e.g., superconducting properties. Finally, although all atoms contribute to the DOS at E F , the contribution of the Rh atoms is the strongest.

  12. Low-energy optics of Sr{sub 1-x}Ca{sub x}RuO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Diana; Scheffler, Marc; Dressel, Martin [1. Physikalisches Institut, Universitaet Stuttgart (Germany); Schneider, Melanie; Gegenwart, Philipp [I. Physikalisches Institut, Georg-August-Universitaet, Goettingen (Germany)

    2012-07-01

    The pseudo-cubic perovskite ruthenates SrRuO{sub 3} and CaRuO{sub 3} have recently attracted interest due to their unconventional electronic properties. For both materials, non-Fermi liquid behavior has been reported in previous optical studies at infrared frequencies. In addition to these two pure compounds, the doping series Sr{sub 1-x}Ca{sub x}RuO{sub 3} offers a rich phase diagram: going from the itinerant ferromagnet SrRuO{sub 3} to the paramagnet CaRuO{sub 3}, indications for a quantum phase transition at x{approx}0.8 have been found. Using THz spectroscopy at frequencies between 5 cm{sup -1} and 45 cm{sup -1}, we have studied thin-film samples of the Sr{sub 1-x}Ca{sub x}RuO{sub 3} system, which were prepared by metalorganic aerosol deposition. From transmission and phase measurements we have determined the frequency-dependent conductivity for a set of temperatures between 5 K and 300 K, and we discuss it in the framework of the extended Drude model with frequency-dependent relaxation rate and effective mass. While for pure SrRuO{sub 3} as well as for doped systems approaching the quantum phase transition we find conventional metallic Drude behavior, CaRuO{sub 3} exhibits highly unusual optical properties which we compare to results of dc measurements on these thin films, which also revealed temperature ranges with non-Fermi liquid behavior.

  13. Novel method of generation of Ca(HCO32 and CaCO3 aerosols and first determination of hygroscopic and cloud condensation nuclei activation properties

    Directory of Open Access Journals (Sweden)

    A. Trimborn

    2010-09-01

    Full Text Available Atmospheric mineral aerosols contain CaCO3 as a reactive component. A novel method to produce CaCO3 aerosol was developed by spraying Ca(HCO32 solution, which was generated from a CaCO3 suspension and CO2. By aerosol mass spectrometry the freshly sprayed and dried aerosol was characterized to consist of pure Ca(HCO32 which under annealing in a tube furnace transformed into CaCO3. Transmission Electron Microscopy demonstrated that the particles produced were spherical. The method was able to generate aerosol of sufficient concentration and proper size for the study of physiochemical properties and investigations of heterogeneous reactions of mineral aerosol. The dried Ca(HCO32 particles were somewhat more hygroscopic than CaCO3 particles. However, during humidification a restructuring took place and ∼2/3 of the Ca(HCO32 was transformed to CaCO3. The mixed Ca(HCO32/CaCO3(s particles were insoluble with a growth factor of 1.03 at 95% (hygroscopicity parameter κ=0.011±0.007 relative humidity. This compares to a corresponding growth factor of 1.01 for CaCO3(s (κ=0.0016±0.0004. Mass spectrometric composition analysis, restructuring, and insolubility of the mixed particles suggested that solid Ca(HCO32(s was observed. This would be in contrast to the current belief that Ca(HCO32(s is thermodynamically instable. The CCN activity of Ca(HCO32(s aerosol (κ≈0.15 is remarkably higher than that of CaCO3 aerosol (κ=0.0019±0.0007 and less than that of Ca(NO32. The noticeable but limited solubility of Ca(HCO32 of ≈0.01 mol/l explains limited hygroscopic growth and good CCN activity. Experiments in the Large Jülich Aerosol Chamber indicated that Ca(HCO32(s could exist for several hours under dry atmospheric conditions. However, it was likely buried in a protective layer of CaCO3(s. We conclude that Ca(HCO32 may be formed in the atmosphere in cloud droplets of activated mineral dust by reaction of CaCO3 with CO2 and H2O. The presence of Ca(HCO32 and

  14. Post-perovskite transitions in CaB4+O3 at high pressure

    International Nuclear Information System (INIS)

    Akaogi, M; Shirako, Y; Kojitani, H; Takamori, S; Yamaura, K; Takayama-Muromachi, E

    2010-01-01

    High-pressure phase transitions in CaRhO 3 were examined using a multianvil apparatus up to 27 GPa and 1930 o C. CaRhO 3 perovskite transforms to post-perovskite via a monoclinic intermediate phase with increasing pressure. Volume changes for the transitions of perovskite - intermediate phase and of intermediate phase - post-perovskite are -1.1 and -0.7 %, respectively. CaRhO 3 post-perovskite is the fourth quenchable post-perovskite oxide found so far. By high-temperature calorimetric experiments, enthalpy of the perovskite - post-perovskite transition in CaRuO 3 was measured as 15.2±3.3 kJ/mol. Combining the datum with those of CaIrO 3 , it is shown that CaIrO 3 perovskite is energetically less stable than CaRuO 3 perovskite. This is consistent with the fact that orthorhombic distortion of CaIrO 3 perovskite is larger than CaRuO 3 , as indicated with the tilt-angle of octahedral framework of perovskite structure. The transition pressure from perovskite to post-perovskite in CaBO 3 (B = Ru, Rh, Ir) increases almost linearly with decreasing the tilt-angle, suggesting that the perovskite - post-perovskite transition may result from instability of the perovskite structure with pressure.

  15. Chemical purification of CaCO{sub 3} and CaWO{sub 4} powders used for CaWO{sub 4} crystal production for the CRESST experiment

    Energy Technology Data Exchange (ETDEWEB)

    Trinh Thi, H.H.; Defay, X.; Erb, A.; Hampf, R.; Lanfranchi, J.C.; Langenkaemper, A.; Morgalyuk, V.; Muenster, A.; Mondragon, E.; Oppenheimer, C.; Potzel, W.; Schoenert, S.; Steiger, H.; Ulrich, A.; Wawoczny, S.; Willers, M.; Zoeller, A. [Physik-Department and Excellence Cluster Universe, Technische Universitaet Muenchen, Garching (Germany)

    2016-07-01

    CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) uses CaWO{sub 4} single crystals as targets for the direct search for dark matter particles. Since several years these CaWO{sub 4} crystals are grown at the Technische Universitaet Muenchen. Thereby, commercially available CaCO{sub 3} and WO{sub 3} powders are used for the synthesis of CaWO{sub 4} powder. For the experiment low intrinsic contaminations of the crystals play a crucial role. In order to improve the radiopurity of the crystals it is necessary to reduce potential sources for radioactive backgrounds such as U and Th. In this poster we will present our studies of the chemical purification of the CaCO{sub 3} and CaWO{sub 4} powders.

  16. Nature of potential barrier in (Ca 1/4,Cu 3/4)TiO 3 polycrystalline perovskite

    Science.gov (United States)

    Marques, V. P. B.; Bueno, P. R.; Simões, A. Z.; Cilense, M.; Varela, J. A.; Longo, E.; Leite, E. R.

    2006-04-01

    The nonohmic electrical features of (Ca 1/4,Cu 3/4)TiO 3 perovskite ceramics, which have very strong gigantic dielectric is believed originate from potential barriers at the grain boundaries. In the present study, we used the admittance and impedance spectroscopy technique to investigate (Ca 1/4,Cu 3/4)TiO 3 perovskite ceramics with low nonohmic electrical properties. The study was conducted under two different conditions: on as-sintered ceramics and on ceramics thermally treated in an oxygen-rich atmosphere. The results confirm that thermal treatment in oxygen-rich atmospheres influence the nonohmic properties. Annealing at oxygen-rich atmospheres improve the nonohmic behavior and annealing at oxygen-poor atmospheres decrease the nonohmic properties, a behavior already reported for common metal oxide nonohmic devices and here firstly evidenced for the (Ca 1/4,Cu 3/4)TiO 3 perovskite related materials. The results show that oxygen also influences the capacitance values at low frequencies, a behavior that is indicative of the Schottky-type nature of the potential barrier.

  17. 1,25(OH)2D3 and Ca-binding protein in fetal rats: Relationship to the maternal vitamin D status

    International Nuclear Information System (INIS)

    Verhaeghe, J.; Thomasset, M.; Brehier, A.; Van Assche, F.A.; Bouillon, R.

    1988-01-01

    The autonomy and functional role of fetal 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] were investigated in nondiabetic and diabetic BB rats fed diets containing 0.85% calcium-0.7% phosphorus or 0.2% calcium and phosphorus and in semistarved rats on the low calcium-phosphorus diet. The changes in maternal and fetal plasma 1,25(OH) 2 D 3 were similar: the levels were increased by calcium-phosphorus restriction and decreased by diabetes and semistarvation. Maternal and fetal 1,25(OH) 2 D 3 levels were correlated. The vitamin D-dependent calcium-binding proteins (CaBP 9K and CaBP 28K ) were measured in multiple maternal and fetal tissues and in the placenta of nondiabetic, diabetic, and calcium-phosphorus-restricted rats. The distributions of CaBP 9K and CaBP 28K in the pregnant rat were similar to that of the growing rat. The increased maternal plasma 1,25(OH) 2 D 3 levels in calcium-phosphorus-restricted rats were associated with higher duodenal CaBP 9K and renal CaBPs, but placental CaBP 9K was not different. In diabetic pregnant rats, duodenal CaBP 9K was not different. In diabetic pregnant rats, duodenal CaBP 9K tended to be lower, while renal CaBPs were normal; placental CaBP 9K was decreased. The results indicate that in the rat fetal 1,25(OH) 2 D 3 depends on maternal 1,25(OH) 2 D 3 or on factors regulating maternal 1,25(OH) 2 D 3 . The lack of changes in fetal CaBP in the presence of altered fetal plasma 1,25(OH) 2 D 3 levels confirms earlier data showing that 1,25(H) 2 D 3 has a limited hormonal function during perinatal development in the rat

  18. Distinct roles of two ceramide synthases, CaLag1p and CaLac1p, in the morphogenesis of Candida albicans

    DEFF Research Database (Denmark)

    Cheon, Seon Ah; Bal, Jyotiranjan; Song, Yunkyoung

    2012-01-01

    p) and Lac1p (CaLac1p) are functionally distinct. Lack of CaLag1p, but not CaLac1p, caused severe defects in the growth and hyphal morphogenesis of C. albicans. Deletion of CaLAG1 decreased expression of the hypha-specific HWP1 and ECE1 genes. Moreover, overexpression of CaLAG1 induced pseudohyphal...... growth in this organism under non-hypha-inducing conditions, suggesting that CaLag1p is necessary for relaying signals to induce hypha-specific gene expression. Analysis of ceramide and sphingolipid composition revealed that CaLag1p predominantly synthesizes ceramides with C24:0/C26:0 fatty acid moieties...

  19. Combined Evaluation of AFP, CA15-3, CA125, CA19-9, and CEA Tumor Markers in Patients with Hepatitis B and C.

    Science.gov (United States)

    Assmar, Mehdi; Yeganeh, Sara; Mansourghanaei, Fariborz; Amirmozafari, Nour

    2016-12-01

    This study aimed to determine the role of tumor markers AFP, CA15-3, CA125, CA19-9 and CEA in patients with hepatitis B and C. This descriptive cross-sectional study was performed from Oct 2012 to Oct 2014. Serum samples of 129 patients with hepatitis B and C referred to Guilan Liver and Digestive Disease Research Center in Rasht, Iran were collected and checked for the existence of the listed tumor markers by ELISA. No increase in serum levels of tumor marker CA19-9, CEA and CA15-3 were seen in patients with hepatitis ( P >0.05). In patients with hepatitis B, increase in CA125 were observed ( P =0.03). In hepatitis C patients, there was an increase in AFP levels ( P =0.03). The levels of AFP and CA125 markers were high in hepatitis C and hepatitis B, respectively. However, the increased levels were not seen is malignancy. Due to the small sample size, further study is necessary to find the reasons of the increase.

  20. Mechanical and thermal-expansion characteristics of Ca10(PO46(OH2-Ca3(PO42 composites

    Directory of Open Access Journals (Sweden)

    Ruseska G.

    2006-01-01

    Full Text Available Three types of composites consisting of Ca10(PO46(OH2 and Ca3(PO42 with composition: 75% (wt Ca10(PO46(OH2: 25%(wt Ca3(PO42; 50%(wt Ca10(PO46(OH2: 50%(wtCa3(PO42 and 25 %(wt Ca10(PO46(OH2: 75%(wt Ca3(PO42 were the subject of our investigation. Sintered compacts were in thermal equilibrium, which was proved by the absence of hysteresis effect of the dependence ΔL/L=f(T during heating /cooling in the temperature interval 20-1000-200C. Sintered compacts with the previously mentioned composition possess 26-50% higher values of the E-modulus, G-modulus and K-modulus indicating the presence of a synergism effect. Several proposed model equations for predicting the thermal expansion coefficient in dependence of the thermal and elastic properties of the constitutive phases and their volume fractions, given by: Turner, Kerner, Tummala and Friedberg, Thomas and Taya, were used for making correlations between mechanical and thermal-expansion characteristics of the Ca10(PO46(OH2 - Ca3(PO42 composites. Application of the previously mentioned model equations to all kinds of composites leads to the conclusion that the experimentally obtained results for the thermal expansion coefficient are in an excellent agreement with the theoretical calculated values on account of the volume fraction of each constitutive phase and with all applied model equations, with a coefficient of correlation from 98.16-99.86 %.

  1. Distribution of calcium channel Ca(V)1.3 immunoreactivity in the rat spinal cord and brain stem.

    Science.gov (United States)

    Sukiasyan, N; Hultborn, H; Zhang, M

    2009-03-03

    The function of local networks in the CNS depends upon both the connectivity between neurons and their intrinsic properties. An intrinsic property of spinal motoneurons is the presence of persistent inward currents (PICs), which are mediated by non-inactivating calcium (mainly Ca(V)1.3) and/or sodium channels and serve to amplify neuronal input signals. It is of fundamental importance for the prediction of network function to determine the distribution of neurons possessing the ion channels that produce PICs. Although the distribution pattern of Ca(V)1.3 immunoreactivity (Ca(V)1.3-IR) has been studied in some specific central nervous regions in some species, so far no systematic investigations have been performed in both the rat spinal cord and brain stem. In the present study this issue was investigated by immunohistochemistry. The results indicated that the Ca(V)1.3-IR neurons were widely distributed across different parts of the spinal cord and the brain stem although with variable labeling intensities. In the spinal gray matter large neurons in the ventral horn (presumably motoneurons) tended to display higher levels of immunoreactivity than smaller neurons in the dorsal horn. In the white matter, a subset of glial cells labeled by an oligodendrocyte marker was also Ca(V)1.3-positive. In the brain stem, neurons in the motor nuclei appeared to have higher levels of immunoreactivity than those in the sensory nuclei. Moreover, a number of nuclei containing monoaminergic cells, for example the locus coeruleus, were also strongly immunoreactive. Ca(V)1.3-IR was consistently detected in the neuronal perikarya regardless of the neuronal type. However, in the large neurons in the spinal ventral horn and the cranial motor nuclei the Ca(V)1.3-IR was clearly detectable in first and second order dendrites. These results indicate that in the rat spinal cord and brain stem Ca(V)1.3 is probably a common calcium channel used by many kinds of neurons to facilitate the neuronal

  2. EFFECT OF FERRITE PHASE ON THE FORMATION AND COEXISTENCE OF 3CaO.3Al₂O₃.CaSO₄ AND 3CaO.SiO₂ MINERALS

    Directory of Open Access Journals (Sweden)

    Xiaolei Lu

    2017-12-01

    Full Text Available The effect of ferrite on the formation and coexistence of 3CaO.3Al₂O₃.CaSO₄ (C₄A₃$ and 3CaO.SiO₂ (C3S was investigated in this paper. The results indicate that 20 % content of ferrite phase with the composition of C₂A0.5F0.5 can facilitate the coexistence of C₄A₃$ and C₃S solid solutions at 1350 ° C. There are other trace elements that incorporate into clinker minerals and form solid solutions. In addition, the dark and polygonal C₄A₃$ solid solution is not dissolved in liquid phase at 1350 ° C. It can promote the burnability of the raw mixes and provide a favorable condition for the formation of C₃S. However, it has an adverse effect on the coexistence of two clinker minerals with the changing of ferrite compositions. This will provide the important basis for the preparation of the calcium sulphoaluminate cement clinker containing C₃S.

  3. Effect of Ca2+ Ions on Electrical Properties of Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 Ceramics

    Science.gov (United States)

    Chen, Zhi-hui; Li, Zhi-wei; Ding, Jian-ning; Zhao, Tian-xiang; Qiu, Jian-hua; Zhu, Ke-qian; Xu, Jiu-jun; Zhang, Bing

    2018-03-01

    Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 (BCTSY) lead-free piezoceramics with x = 0.02 to 0.10 have been fabricated by solid-state sintering method at 1420°C. The effects of Ca2+ ions on the microstructure and electrical properties of the samples were studied. X-ray diffraction analysis showed that all samples possessed pure perovskite structure with Ca2+ ions diffused into the matrix lattice. The rhombohedral phase and tetragonal phase coexisted in the composition range of 0.02 ceramic became more homogeneous with addition of Ca2+ ions, and the average grain size of the samples decreased from 97 μm (x = 0.02) to 18 μm (x = 0.10). Addition of Ca2+ remarkably improved the piezoelectric properties, enhanced the dielectric frequency dispersion, and increased the Curie temperature of the ceramics. The piezoelectric properties of the ceramics were optimized at x = 0.04 with d 33 and K p values of 579 pC/N and 52.7%, respectively.

  4. Phase formation, structural and microstructural characterization of novel oxynitride-perovskites synthesized by thermal ammonolysis of (Ca,Ba)MoO4 and (Ca,Ba)MoO3

    International Nuclear Information System (INIS)

    Logvinovich, D.; Aguirre, M.H.; Hejtmanek, J.; Aguiar, R.; Ebbinghaus, S.G.; Reller, A.; Weidenkaff, A.

    2008-01-01

    Reactions of AMoO 4 and AMoO 3 (A=Ca 2+ , Ba 2+ ) with ammonia were investigated at 873 K 3 and to study their crystal structure. CaMo(O,N) 3 and BaMo(O,N) 3 were prepared by thermal ammonolysis of the corresponding CaMoO 3 and BaMoO 3 precursors at T=898 and 998 K, respectively. The structural parameters of the oxynitrides were obtained from Rietveld refinements of X-ray and neutron powder diffraction data. CaMo(O,N) 3 crystallizes in the GdFeO 3 distorted perovskite structure with orthorhombic space group Pbnm and a=5.5029(1) A, b=5.5546(1) A, c=7.8248(1) A as determined by X-ray powder diffraction. Its O/N content refined from the neutron diffraction data corresponds to the composition CaMoO 1.7(1) N 1.3(1) . BaMo(O,N) 3 crystallizes in the cubic perovskite structure with space group Pm3-bar m and a=4.0657(1) A as determined by X-ray powder diffraction. Transmission electron microscopy reveals a complex microstructure for both CaMoO 3 and CaMoO 1.7(1) N 1.3(1) represented by twin domains of different orientation. - Graphical abstract: Reactions of AMoO 4 and AMoO 3 (A=Ca 2+ , Ba 2+ ) oxides with ammonia have been studied at T=873-1123 K. Orthorhombic CaMoO 1.7(1) N 1.3(1) (Pbnm) and cubic BaMo(O,N) 3 (Pm3-bar m) were prepared by thermal ammonolysis of the corresponding CaMoO 3 and BaMoO 3 precursors at T=898 and 998 K, respectively. Display Omitted

  5. Effect of Ca doping level on the laser-induced voltages in tilted La{sub 1-x}Ca{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.7) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ji; Zhang, Hui; Chen, Qingming; Liu, Xiang [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China); Theingi, Mya [Kunming University of Science and Technology, Faculty of Materials Science and Engineering, Kunming (China); University of Yangon, Department of Chemistry, Yangon (Myanmar)

    2014-03-15

    Tilted La{sub 1-x}Ca{sub x}MnO{sub 3} (0.1 ≤ x ≤ 0.7) thin films have been grown on vicinal cut LaAlO{sub 3} (100) substrate by pulsed laser deposition. The laser-induced voltage effect was studied at room temperature with the KrF excimer laser using as the thermal source. The relationships between Ca doping level and voltage signal, response time and anisotropy Seebeck coefficient were established. The voltage signal and anisotropy Seebeck coefficient increase at first with increasing Ca doping level, reach a maximum at the same Ca content around x = 0.5, and then decrease. The respond time decreases with the Ca concentration increasing, and changes very little after x = 0.5. The figure of merit F{sub m} was also the largest at this doping level, indicating a potential good performance of the photodetector devices. The variation of intrinsic structural and transport anisotropy induced by the change of Ca concentration has been proposed to account for the different LIV effects observed in LCMO thin films. (orig.)

  6. Morphometric characteristics of the neurons of the human subiculum proper

    Directory of Open Access Journals (Sweden)

    Živanović-Mačužić Ivana

    2012-01-01

    Full Text Available The human subiculum is a significant part of the hippocampal formation positioned between the hippocampus proper and the entorhinal and other cortices. It plays an important role in spatial navigation, memory processing and control of the response to stress. The aim of our study was identification of the morphometric characteristics of the neurons of the human subiculum proper: the maximum length and width of cell body and total dendritic length and volume of cell body. Comparing the measured parameters of different types of subicular neurons (bipolar, multipolar, pyramidal neurons with triangular-shaped soma and neurons with oval-shaped soma, we can conclude that bipolar neurons have the lowest values of the measured parameters: the maximum length of their cell body is 14.1 ± 0.2 µm, the maximum width is 13.9 ± 0.5 µm, and total dendritic length is 14597 ± 3.1 µm. The lowest volume value was observed in bipolar neurons; the polymorphic layer is 1152.99 ± 662.69 µm3. The pyramidal neurons of the pyramidal layer have the highest value for the maximal length of the cell body (44.43 ± 7.94 µm, maximum width (23.64 ± 1.89 µm, total dendritic length (1830 ± 466.3 µm and volume (11768.65±4004.9 µm3 These characteristics of the pyramidal neurons indicate their importance, because the axons of these neurons make up the greatest part of the fornix, along with the axons of neurons of the CA1 hippocampal field.

  7. Comparison of CA15-3 and CEA in breast cancer

    International Nuclear Information System (INIS)

    Rajkovaca, Z.; Mijatovic, J.; Matavulj, A.; Kovacevic, P.; Ponorac, N.

    2002-01-01

    Aim: Tumor markers are potentially powerful means for obtaining information about cancers whilst causing minimal morbidity, inconvenience and cost. CA 15-3 and CEA are considered useful tumor markers in monitoring breast cancer patients. The aim of this study was to evaluate which of these two markers are in better correlate with the disease in patients surgically treated for breast cancer. Material and Methods: We retrospectively reviewed values of CA15-3 and CEA in 342 patients (median age 52.18 years, range 27-78 years) with surgically treated and pathologically proven breast cancer. CA15-3 and CEA was measured by radioimmunoassay. CA15-3 levels above 30 U/ml and CEA levels above 5 ng/ml were considered as positive values. Results: Out of 342 patients, 86 had elevated CA15-3 levels (sensitivity: 25.1%) and 68 of 342 patients had positive CEA levels (sensitivity 19.9%). Two hundred thirty seven (237) of the patients suffering from breast cancer (69.3%) did not have metastatic disease. In this group CA15-3 sensitivity was 94.5%, while CEA sensitivity was 87.3%. One hundred and five (105) patients (30.7%) had metastatic disease. In this group, CA15-3 sensitivity was 69.5% and CEA sensitivity was 36.2% (P < 0.05). With regard to the correlation of the two tumor markers with clinical course patients had significantly higher levels of CA15-3 than of CEA in metastatic breast cancer. Conclusion: This result suggests CA15-3 to be the more sensitive and more specific of the two tumor markers for metastatic breast cancer detection and monitoring

  8. A role for CA3 in social recognition memory.

    Science.gov (United States)

    Chiang, Ming-Ching; Huang, Arthur J Y; Wintzer, Marie E; Ohshima, Toshio; McHugh, Thomas J

    2018-02-02

    Social recognition memory is crucial for survival across species, underlying the need to correctly identify conspecifics, mates and potential enemies. In humans the hippocampus is engaged in social and episodic memory, however the circuit mechanisms of social memory in rodent models has only recently come under scrutiny. Work in mice has established that the dorsal CA2 and ventral CA1 regions play critical roles, however a more comprehensive comparative analyses of the circuits and mechanisms required has not been reported. Here we employ conditional genetics to examine the differential contributions of the hippocampal subfields to social memory. We find that the deletion of NMDA receptor subunit 1 gene (NR1), which abolishes NMDA receptor synaptic plasticity, in CA3 pyramidal cells led to deficits in social memory; however, mice lacking the same gene in DG granule cells performed indistinguishable from controls. Further, we use conditional pharmacogenetic inhibition to demonstrate that activity in ventral, but not dorsal, CA3 is necessary for the encoding of a social memory. These findings demonstrated CA3 pyramidal cell plasticity and transmission contribute to the encoding of social stimuli and help further identify the distinct circuits underlying the role of the hippocampus in social memory. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Reorganization of Basolateral Amygdala-Subiculum Circuitry in Mouse Epilepsy Model

    Directory of Open Access Journals (Sweden)

    Dongliang eMa

    2016-01-01

    Full Text Available In this study, we investigated the reorganized basolateral amygdala (BLA-subiculum pathway in a status epilepticus (SE mouse model with epileptic episodes induced by pilocarpine. We have previously observed a dramatic loss of neurons in the CA1-3 fields of the hippocampus in epileptic mice. Herein, we observed a 43-57 % reduction in the number of neurons in the BLA of epileptic mice. However, injection of an anterograde tracer, Phaseolus vulgaris leucoagglutinin (PHA-L into the BLA indicated 25.63 % increase in the number of PHA-L-immunopositive terminal-like structures in the ventral subiculum (v-Sub of epileptic mice as compared to control mice. These data suggest that the projections from the basal nucleus at BLA to the vSub in epileptic mice are resistant to epilepsy-induced damage. Consequently, these epileptic mice exhibit partially impairment but not total loss of context-dependent fear memory. Epileptic mice also show increased c-Fos expression in the BLA and vSub when subjected to contextual memory test, suggesting the participation of these 2 brain areas in foot shock-dependent fear conditioning. These results indicate the presence of functional neural connections between the BLA-vSub regions that participate in learning and memory in epileptic mice.

  10. PGC-1{alpha} accelerates cytosolic Ca{sup 2+} clearance without disturbing Ca{sup 2+} homeostasis in cardiac myocytes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min, E-mail: chenminyx@gmail.com [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Yunnan Centers for Diseases Prevention and Control, Kunming 650022 (China); Wang, Yanru [Institute of Molecular Medicine, State Key Laboratory of Biomembrane and Membrane Biotechnology, Peking University, Beijing 100871 (China); Qu, Aijuan [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States)

    2010-06-11

    Energy metabolism and Ca{sup 2+} handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1{alpha}) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1{alpha} in cardiac Ca{sup 2+} signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1{alpha} via adenoviral transduction. Our data shows that overexpressing PGC-1{alpha} improved myocyte contractility without increasing the amplitude of Ca{sup 2+} transients, suggesting that myofilament sensitivity to Ca{sup 2+} increased. Interestingly, the decay kinetics of global Ca{sup 2+} transients and Ca{sup 2+} waves accelerated in PGC-1{alpha}-expressing cells, but the decay rate of caffeine-elicited Ca{sup 2+} transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca{sup 2+}-ATPase (SERCA2a), but not Na{sup +}/Ca{sup 2+} exchange (NCX) contribute to PGC-1{alpha}-induced cytosolic Ca{sup 2+} clearance. Furthermore, PGC-1{alpha} induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1{alpha} did not disturb cardiac Ca{sup 2+} homeostasis, because SR Ca{sup 2+} load and the propensity for Ca{sup 2+} waves remained unchanged. These data suggest that PGC-1{alpha} can ameliorate cardiac Ca{sup 2+} cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1{alpha}-calcium handing pathway sheds new light on the role of PGC-1{alpha} in the therapy of cardiac diseases.

  11. Interaction of peridotite with Ca-rich carbonatite melt at 3.1 and 6.5 GPa: Implication for merwinite formation in upper mantle, and for the metasomatic origin of sublithospheric diamonds with Ca-rich suite of inclusions

    Science.gov (United States)

    Sharygin, Igor S.; Shatskiy, Anton; Litasov, Konstantin D.; Golovin, Alexander V.; Ohtani, Eiji; Pokhilenko, Nikolay P.

    2018-03-01

    We performed an experimental study, designed to reproduce the formation of an unusual merwinite + olivine-bearing mantle assemblage recently described as a part of a Ca-rich suite of inclusions in sublithospheric diamonds, through the interaction of peridotite with an alkali-rich Ca-carbonatite melt, derived from deeply subducted oceanic crust. In the first set of experiments, we studied the reaction between powdered Mg-silicates, olivine and orthopyroxene, and a model Ca-carbonate melt (molar Na:K:Ca = 1:1:2), in a homogeneous mixture, at 3.1 and 6.5 GPa. In these equilibration experiments, we observed the formation of a merwinite + olivine-bearing assemblage at 3.1 GPa and 1200 °C and at 6.5 GPa and 1300-1400 °C. The melts coexisting with this assemblage have a low Si and high Ca content (Ca# = molar 100 × Ca/(Ca + Mg) > 0.57). In the second set of experiments, we investigated reaction rims produced by interaction of the same Ca-carbonate melt (molar Na:K:Ca = 1:1:2) with Mg-silicate, olivine and orthopyroxene, single crystals at 3.1 GPa and 1300 °C and at 6.5 GPa and 1400 °C. The interaction of the Ca-carbonate melt with olivine leads to merwinite formation through the expected reaction: 2Mg2SiO4 (olivine) + 6CaCO3 (liquid) = Ca3MgSi2O8 (merwinite) + 3CaMg(CO3)2 (liquid). Thus, our experiments confirm the idea that merwinite in the upper mantle may originate via interaction of peridotite with Ca-rich carbonatite melt, and that diamonds hosting merwinite may have a metasomatic origin. It is remarkable that the interaction of the Ca-carbonate melt with orthopyroxene crystals does not produce merwinite both at 3.1 and 6.5 GPa. This indicates that olivine grain boundaries are preferable for merwinite formation in the upper mantle.

  12. Effect of 1,25(OH)2 vitamin D3 and ionized Ca2+ on 45Ca uptake by primary cultures of aortic myocytes of spontaneously hypertensive and Wistar Kyoto normotensive rats

    International Nuclear Information System (INIS)

    Bukoski, R.D.; Xue, H.; McCarron, D.A.

    1987-01-01

    The effect of several regulators of whole animal Ca 2+ homeostasis on 45 Ca uptake by primary cultures of aortic myocytes isolated from spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats was examined. Exposure of confluent cells to 1.0, 1.25 or 1.50 mM ionized Ca 2+ in serum-free medium for seven days resulted in increased 45 Ca uptake at the higher concentrations of Ca 2+ in cells of the SHR but not the WKY. 1,25 (OH)2 vitamin D3 (1 ng/ml) for 7 days caused enhanced influx in cells from both the SHR and WKY while parathyroid hormone (1-34) (1 ng/ml) was without effect. The data indicate that humoral factors that serve to regulate whole animal Ca 2+ homeostasis may also play a role in the regulation of Ca 2+ metabolism of the vascular smooth muscle cell

  13. PIK3CA Mutation in Colorectal Cancer: Relationship with Genetic and Epigenetic Alterations

    Directory of Open Access Journals (Sweden)

    Katsuhiko Nosho

    2008-06-01

    Full Text Available Somatic PIK3CA mutations are often present in colorectal cancer. Mutant PIK3CA activates AKT signaling, which up-regulates fatty acid synthase (FASN. Microsatellite instability (MSI and CpG island methylator phenotype (CIMP are important molecular classifiers in colorectal cancer. However, the relationship between PIK3CA mutation, MSI and CIMP remains uncertain. Using Pyrosequencing technology, we detected PIK3CA mutations in 91 (15% of 590 population-based colorectal cancers. To determine CIMP status, we quantified DNA methylation in eight CIMP-specific promoters [CACNA1G, CDKN2A (p16, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1] by real-time polymerase chain reaction (MethyLight. PIK3CA mutation was significantly associated with mucinous tumors [P = .0002; odds ratio (OR = 2.44], KRAS mutation (P < .0001; OR = 2.68, CIMP-high (P = .03; OR = 2.08, phospho–ribosomal protein S6 expression (P = .002; OR = 2.19, and FASN expression (P = .02; OR = 1.85 and inversely with p53 expression (P = .01; OR = 0.54 and β-catenin (CTNNB1 alteration (P = .004; OR = 0.43. In addition, PIK3CA G-to-A mutations were associated with MGMT loss (P = .001; OR = 3.24 but not with MGMT promoter methylation. In conclusion, PIK3CA mutation is significantly associated with other key molecular events in colorectal cancer, and MGMT loss likely contributes to the development of PIK3CA G>A mutation. In addition, Pyrosequencing is useful in detecting PIK3CA mutation in archival paraffin tumor tissue. PIK3CA mutational data further emphasize heterogeneity of colorectal cancer at the molecular level.

  14. Significance of the tumor markers CA 125 and CA 15-3 in postoperative diagnosis of ovarian and breast cancer

    International Nuclear Information System (INIS)

    Johannsen, B.; Bartel, U.; Elling, D.

    1989-01-01

    In 271 patients with ovarian carcinoma, benign ovarian tumors, breast cancer, and two control groups, serum levels of CA 125, CA 15-3, CEA and, partly, CA 19-9 were determined immunoradiometrically. According to the results of the determination of CA 125 in the follow-up of ovarian carcinoma, CA 125 represents a useful marker for early detection of recurrences, especially in cases of diffuse carcinoma dissemination. In incomplete tumor debulking, postoperative CA 125 serum levels did not prove to be helpful except that a positive level renders invasive diagnostic investigation no longer necessary. Postoperative follow-up in breast cancer early reveals distant metastases, with very high levels in patients with bone metastases. By simultaneous measurement of CA 15-3 and CEA the sensitivity could be increased from 86% (CA 15-3 only) to 93%. (author)

  15. Ablation of CaV2.1 Voltage-Gated Ca2+ Channels in Mouse Forebrain Generates Multiple Cognitive Impairments

    Science.gov (United States)

    Mallmann, Robert Theodor; Elgueta, Claudio; Sleman, Faten; Castonguay, Jan; Wilmes, Thomas; van den Maagdenberg, Arn; Klugbauer, Norbert

    2013-01-01

    Voltage-gated CaV2.1 (P/Q-type) Ca2+ channels located at the presynaptic membrane are known to control a multitude of Ca2+-dependent cellular processes such as neurotransmitter release and synaptic plasticity. Our knowledge about their contributions to complex cognitive functions, however, is restricted by the limited adequacy of existing transgenic CaV2.1 mouse models. Global CaV2.1 knock-out mice lacking the α1 subunit Cacna1a gene product exhibit early postnatal lethality which makes them unsuitable to analyse the relevance of CaV2.1 Ca2+ channels for complex behaviour in adult mice. Consequently we established a forebrain specific CaV2.1 knock-out model by crossing mice with a floxed Cacna1a gene with mice expressing Cre-recombinase under the control of the NEX promoter. This novel mouse model enabled us to investigate the contribution of CaV2.1 to complex cognitive functions, particularly learning and memory. Electrophysiological analysis allowed us to test the specificity of our conditional knock-out model and revealed an impaired synaptic transmission at hippocampal glutamatergic synapses. At the behavioural level, the forebrain-specific CaV2.1 knock-out resulted in deficits in spatial learning and reference memory, reduced recognition memory, increased exploratory behaviour and a strong attenuation of circadian rhythmicity. In summary, we present a novel conditional CaV2.1 knock-out model that is most suitable for analysing the in vivo functions of CaV2.1 in the adult murine forebrain. PMID:24205277

  16. Size-driven magnetic transitions in La1/3Ca2/3MnO3 nanoparticles

    Science.gov (United States)

    Markovich, V.; Fita, I.; Wisniewski, A.; Mogilyansky, D.; Puzniak, R.; Titelman, L.; Gorodetsky, G.

    2010-09-01

    Magnetic properties of electron-doped La1/3Ca2/3MnO3 manganite nanoparticles with average particle size ranging from 12 to 42 nm, prepared by the glycine-nitrate method, have been investigated in temperature range 5-300 K and in magnetic fields up to 90 kOe. Reduction in the particle size suppresses antiferromagnetism and decreases the Néel temperature. In contrast to bulk crystals, the charge ordering does not occur in all studied nanoparticles, while a weak ferromagnetism appears above 200 K. Low temperature magnetic hysteresis loops indicate upon exchange bias effect displayed by horizontal and vertical shifts in field cooled processes. The spontaneous and remanent magnetization at low temperature shows a relatively complex variation with particle size. The size-induced structural/magnetic disorder drives the La1/3Ca2/3MnO3 nanoparticles to a pronounced glassy behavior for the smallest 12 nm particles, as evidenced by large difference between zero field cooled and field cooled magnetization, frequency dependent ac-susceptibility, as well as characteristic slowing down in the spin dynamics. Time evolution of magnetization recorded in magnetic fields after field cooling to low temperatures exhibits pronounced relaxation and a very noisy behavior that may be caused by formation of some collective states. Magnetic properties of the nanoparticle samples are compared with those of La0.2Ca0.8MnO3 nanoparticles. These results shed some light on the coupling between charges and spin degrees of freedom in antiferromagnetic manganite nanoparticles.

  17. The interhemispheric CA1 circuit governs rapid generalisation but not fear memory.

    Science.gov (United States)

    Zhou, Heng; Xiong, Gui-Jing; Jing, Liang; Song, Ning-Ning; Pu, De-Lin; Tang, Xun; He, Xiao-Bing; Xu, Fu-Qiang; Huang, Jing-Fei; Li, Ling-Jiang; Richter-Levin, Gal; Mao, Rong-Rong; Zhou, Qi-Xin; Ding, Yu-Qiang; Xu, Lin

    2017-12-19

    Encoding specificity theory predicts most effective recall by the original conditions at encoding, while generalization endows recall flexibly under circumstances which deviate from the originals. The CA1 regions have been implicated in memory and generalization but whether and which locally separated mechanisms are involved is not clear. We report here that fear memory is quickly formed, but generalization develops gradually over 24 h. Generalization but not fear memory is impaired by inhibiting ipsilateral (ips) or contralateral (con) CA1, and by optogenetic silencing of the ipsCA1 projections onto conCA1. By contrast, in vivo fEPSP recordings reveal that ipsCA1-conCA1 synaptic efficacy is increased with delay over 24 h when generalization is formed but it is unchanged if generalization is disrupted. Direct excitation of ipsCA1-conCA1 synapses using chemogenetic hM3Dq facilitates generalization formation. Thus, rapid generalization is an active process dependent on bilateral CA1 regions, and encoded by gradual synaptic learning in ipsCA1-conCA1 circuit.

  18. Grain refinement of Ca addition in a twin-roll-cast Mg-3Al-1Zn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Bin, E-mail: jiangbinrong@cqu.edu.cn [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China); College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); Liu Wenjun [College of Materials Science and Engineering, Chongqing University, Chongqing 400030 (China); Qiu Dong; Zhang Mingxing [Division of Materials, School of Mechanical and Mining Engineering, University of Queensland, St Lucia, QLD 4072 (Australia); Pan Fusheng [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030 (China)

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer Grain refinement of Ca addition in a twin-roll-cast Mg-3Al-1Zn alloy was investigated. Black-Right-Pointing-Pointer Addition of 0.08 wt% Ca into Mg melts can significantly reduce the grain size to 30 {mu}m from 100 {mu}m. Black-Right-Pointing-Pointer Al{sub 2}Ca intermetallic particles have high potency to act as heterogeneous nucleation sites for {alpha}-Mg. - Abstract: Addition of 0.08 wt% Ca into AZ31 melts significantly reduces the average grain size of thin strips produced by twin-roll-cast to 30 {mu}m from 100 {mu}m. Like Zr, due to the high chemical activity, the Ca added into the melts reacts with Al and forms Al{sub 2}Ca intermetallic compound. X-ray diffraction result approves the existence of Al{sub 2}Ca in the thin strips, which formed in the melts. Crystallographic examination of relationship between Al{sub 2}Ca and Mg using the edge-to-edge matching model indicates that Al{sub 2}Ca particles are effective inoculants for heterogeneous nucleation of Mg. It is considered that Al{sub 2}Ca is a potential and effective grain refiner for Mg alloys and the grain refinement through addition of Ca in the AZ31 alloy is attributed to the inoculation effect of Al{sub 2}Ca particles formed in the melts.

  19. Electrical and magnetic behavior of La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/La{sub 0.7}Sr{sub 0.2}Ca{sub 0.1}MnO{sub 3} composites

    Energy Technology Data Exchange (ETDEWEB)

    Phong, P.T., E-mail: ptphong.nh@khanhhoa.edu.v [Nhatrang Pedagogic College, Khanhhoa (Viet Nam); Institute of Material Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Dai, N.V.; Manh, D.H.; Thanh, T.D. [Institute of Material Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam); Khiem, N.V. [Department of Natural Sciences, Hongduc University, Thanhhoa (Viet Nam); Hong, L.V.; Phuc, N.X. [Institute of Material Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam)

    2010-09-15

    The electrical transport properties and the magnetoresistance of La{sub 0.7}Ca{sub 0.3}MnO{sub 3}/La{sub 0.7}Sr{sub 0.2}Ca{sub 0.1}MnO{sub 3} composites are investigated as a function of sintering temperature. On the basis of an analysis by X-ray powder diffraction and scanning electron microscopy we suggest that raising the sintering temperature enhanced the interfacial reaction and creates interfacial phases at the boundaries of the La{sub 0.7}Ca{sub 0.3}MnO{sub 3} and La{sub 0.7}Sr{sub 0.2}Ca{sub 0.1}MnO{sub 3}. Results also show that in 3 kOe, and at the Curie temperature, the magnetoresistance value of 14% was observed for the composite sintered at 1300 {sup o}C. Based on the phenomenological equation for conductivity under a percolation approach, which depends on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions, we fitted the experimental resistivity-temperature data from 50-300 K and find that the activation barrier decreases as temperature is increased.

  20. Filling the holes in the CaFe4As3 structure: Synthesis and magnetism of CaCo5As3

    Science.gov (United States)

    Rosa, P. F. S.; Scott, B. L.; Ronning, F.; Bauer, E. D.; Thompson, J. D.

    2017-07-01

    Here, we investigate single crystals of CaCo5As3 by means of single-crystal x-ray diffraction, microprobe, magnetic susceptibility, heat capacity, and pressure-dependent transport measurements. CaCo5As3 shares the same structure of CaFe4As3 with an additional Co atom filling a lattice vacancy and undergoes a magnetic transition at TM=16 K associated with a frustrated magnetic order. CaCo5As3 displays metallic behavior and its Sommerfeld coefficient (γ =70 mJ/mol K2) indicates a moderate enhancement of electron-electron correlations. Transport data under pressures to 2.5 GPa reveal a suppression of TM at a rate of -0.008 K/GPa. First-principles electronic structure calculations show a complex three-dimensional band structure and magnetic moments that depend on the local environment at each Co site. Our results are compared with previous data on CaFe4As3 and provide a scenario for a magnetically frustrated ground state in this family of compounds.

  1. The transcriptional repressor Zbtb20 is essential for specification of hippocampal projection neurons and territory in mice

    DEFF Research Database (Denmark)

    Rosenthal, Eva Helga

    for specification of both hippocampal pyramidal neurons and territory in a mouse knockout model. Homozygous Zbtb20-/- mice are viable at birth, but display dwarfism and die during the first month of postnatal life. Characterization of the Zbtb20-/- brain phenotype reveals a small vestigial hippocampus...... with a dramatic change in the molecular patterning of the subiculum and Ammon’s horn. In absence of Zbtb20, the pattern of expression of distinct molecular markers was altered at four borders: retrosplenial cortex/subiculum, subiculum/CA1, CA1/CA2, and CA2/CA3, leading to a replacement of Ammon’s horn...

  2. Focal CA3 hippocampal subfield atrophy following LGI1 VGKC-complex antibody limbic encephalitis

    OpenAIRE

    Miller, T; Chong, T; Aimola Davies, A; Ng, T; Johnson, M; Irani, S; Vincent, A; Husain, M; Jacob, S; Maddison, P; Kennard, C; Gowland, P; Rosenthal, C

    2017-01-01

    Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0....

  3. Size and receptor density of glutamatergic synapses: a viewpoint from left-right asymmetry of CA3-CA1 connections

    Directory of Open Access Journals (Sweden)

    Yoshiaki Shinohara

    2009-07-01

    Full Text Available Synaptic plasticity is considered to be the main mechanism for learning and memory. Excitatory synapses in the cerebral cortex and hippocampus undergo plastic changes during development and in response to electric stimulation. It is widely accepted that this process is mediated by insertion and elimination of various glutamate receptors. In a series of recent investigations on left-right asymmetry of hippocampal CA3-CA1 synapses, glutamate receptor subunits have been found to have distinctive expression patterns that depend on the postsynaptic density (PSD area. Particularly notable are the GluR1 AMPA receptor subunit and NR2B NMDA receptor subunit, where receptor density has either a supra-linear (GluR1 AMPA or inverse (NR2B NMDAR relationship to the PSD area. We review current understanding of structural and physiological synaptic plasticity and propose a scheme to classify receptor subtypes by their expression pattern with respect to PSD area.

  4. Functional Properties of a Newly Identified C-terminal Splice Variant of Cav1.3 L-type Ca2+ Channels*

    Science.gov (United States)

    Bock, Gabriella; Gebhart, Mathias; Scharinger, Anja; Jangsangthong, Wanchana; Busquet, Perrine; Poggiani, Chiara; Sartori, Simone; Mangoni, Matteo E.; Sinnegger-Brauns, Martina J.; Herzig, Stefan; Striessnig, Jörg; Koschak, Alexandra

    2011-01-01

    An intramolecular interaction between a distal (DCRD) and a proximal regulatory domain (PCRD) within the C terminus of long Cav1.3 L-type Ca2+ channels (Cav1.3L) is a major determinant of their voltage- and Ca2+-dependent gating kinetics. Removal of these regulatory domains by alternative splicing generates Cav1.342A channels that activate at a more negative voltage range and exhibit more pronounced Ca2+-dependent inactivation. Here we describe the discovery of a novel short splice variant (Cav1.343S) that is expressed at high levels in the brain but not in the heart. It lacks the DCRD but, in contrast to Cav1.342A, still contains PCRD. When expressed together with α2δ1 and β3 subunits in tsA-201 cells, Cav1.343S also activated at more negative voltages like Cav1.342A but Ca2+-dependent inactivation was less pronounced. Single channel recordings revealed much higher channel open probabilities for both short splice variants as compared with Cav1.3L. The presence of the proximal C terminus in Cav1.343S channels preserved their modulation by distal C terminus-containing Cav1.3- and Cav1.2-derived C-terminal peptides. Removal of the C-terminal modulation by alternative splicing also induced a faster decay of Ca2+ influx during electrical activities mimicking trains of neuronal action potentials. Our findings extend the spectrum of functionally diverse Cav1.3 L-type channels produced by tissue-specific alternative splicing. This diversity may help to fine tune Ca2+ channel signaling and, in the case of short variants lacking a functional C-terminal modulation, prevent excessive Ca2+ accumulation during burst firing in neurons. This may be especially important in neurons that are affected by Ca2+-induced neurodegenerative processes. PMID:21998310

  5. Perirhinal cortical inactivation impairs object-in-place memory and disrupts task-dependent firing in hippocampal CA1, but not in CA3.

    Science.gov (United States)

    Lee, Inah; Park, Seong-Beom

    2013-01-01

    Objects and their locations can associatively define an event and a conjoint representation of object-place can form an event memory. Remembering how to respond to a certain object in a spatial context is dependent on both hippocampus and perirhinal cortex (PER). However, the relative functional contributions of the two regions are largely unknown in object-place associative memory. We investigated the PER influence on hippocampal firing in a goal-directed object-place memory task by comparing the firing patterns of CA1 and CA3 of the dorsal hippocampus between conditions of PER muscimol inactivation and vehicle control infusions. Rats were required to choose one of the two objects in a specific spatial context (regardless of the object positions in the context), which was shown to be dependent on both hippocampus and PER. Inactivation of PER with muscimol (MUS) severely disrupted performance of well-trained rats, resulting in response bias (i.e., choosing any object on a particular side). MUS did not significantly alter the baseline firing rates of hippocampal neurons. We measured the similarity in firing patterns between two trial conditions in which the same target objects were chosen on opposite sides within the same arm [object-in-place (O-P) strategy] and compared the results with the similarity in firing between two trial conditions in which the rat chose any object encountered on a particular side [response-in-place (R-P) strategy]. We found that the similarity in firing patterns for O-P trials was significantly reduced with MUS compared to control conditions (CTs). Importantly, this was largely because MUS injections affected the O-P firing patterns in CA1 neurons, but not in CA3. The results suggest that PER is critical for goal-directed organization of object-place associative memory in the hippocampus presumably by influencing how object information is associated with spatial information in CA1 according to task demand.

  6. Perirhinal cortical inactivation impairs object-in-place memory and disrupts task-dependent firing in hippocampal CA1, but not in CA3

    Directory of Open Access Journals (Sweden)

    Inah eLee

    2013-08-01

    Full Text Available Objects and their locations can associatively define an event and a conjoint representation of object-place can form an event memory. Remembering how to respond to a certain object in a spatial context is dependent on both hippocampus and perirhinal cortex (PER. However, the relative functional contributions of the two regions are largely unknown in object-place associative memory. We investigated the PER influence on hippocampal firing in a goal-directed object-place memory task by comparing the firing patterns of CA1 and CA3 of the dorsal hippocampus between conditions of PER muscimol inactivation and vehicle control infusions. Rats were required to choose one of the two objects in a specific spatial context (regardless of the object positions in the context, which was shown to be dependent on both hippocampus and PER. Inactivation of PER with muscimol (MUS severely disrupted performance of well-trained rats, resulting in response bias (i.e., choosing any object on a particular side. MUS did not significantly alter the baseline firing rates of hippocampal neurons. We measured the similarity in firing patterns between two trial conditions in which the same target objects were chosen on opposite sides within the same arm (object-in-place strategy and compared the results with the similarity in firing between two trial conditions in which the rat chose any object encountered on a particular side (response-in-place strategy. We found that the similarity in firing patterns for object-in-place trials was significantly reduced with MUS compared to control conditions. Importantly, this was largely because MUS injections affected the object-in-place firing patterns in CA1 neurons, but not in CA3. The results suggest that PER is critical for goal-directed organization of object-place associative memory in the hippocampus presumably by influencing how object information is associated with spatial information in CA1 according to task demand.

  7. Photoemission study of Ca-intercalated graphite superconductor CaC6

    International Nuclear Information System (INIS)

    Okazaki, Hiroyuki; Yoshida, Rikiya; Iwai, Keisuke; Noami, Kengo; Muro, Takayuki; Nakamura, Tetsuya; Wakita, Takanori; Muraoka, Yuji; Hirai, Masaaki; Tomioka, Fumiaki; Takano, Yoshihiko; Takenaka, Asami; Toyoda, Masahiro; Oguchi, Tamio; Yokoya, Takayoshi

    2010-01-01

    In this work, we have performed resonant photoemission studies of Ca-intercalated graphite superconductor CaC 6 . Using photon energy of the Ca 2p-3d threshold, the photoemission intensity of the peak at Fermi energy (E F ) is resonantly enhanced. This result provides spectroscopic evidence for the existence of Ca 3d states at E F , and strongly supports that Ca 3d state plays a crucial role for the superconductivity of this material with relatively high T c .

  8. Effect of Nd substitution for Ca on crystal structure, optical and magnetic properties of multiferroic Bi{sub 0.9}Ca{sub 0.1}FeO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Chuye; Ma, Yuhui; Han, Yumin; Tang, Xingxing; Lu, Mengjia [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Mao, Weiwei [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023 (China); Zhang, Jian [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); Yang, Jianping [School of Science, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023 (China); Li, Xing’ao, E-mail: lxahbmy@126.com [Key Laboratory for Organic Electronics & Information Displays (KLOEID), Synergetic Innovation Center for Organic Electronics and Information Displays (SICOEID), Institute of Advanced Materials - IAM, School of Materials Science and Engineering - SMSE, Nanjing University of Posts and Telecommunications - NUPT, Nanjing 210023 (China); and others

    2015-06-25

    Highlights: • Crystal structure of doped samples transform to two phase coexistence. • The crystal size decreased to ∼50 nm after doping. • Ultraviolet absorption peak demonstrates apparent blue shift for doped sample. • The ratio of Fe{sup 2+} increased by merging Nd. • Ca, Nd co-doped can promote the ferromagnetism obviously. - Abstract: Pure and co-doped BiFeO{sub 3} (Ca, Nd) nanoparticles with diameter in the range of 50–250 nm were synthesized through a sol–gel method. X-ray diffraction (XRD) and Raman results show that Bi-site co-doped with Ca, Nd could result in a transition of crystal structure (from single phase rhombohedral (R3c) to two phase coexistence). An apparent blue shift can be observed in the co-doped samples along with a decrease of the direct optical band gap. Moreover, the leakage current was decreased due to the introduction of nonvolatile Ca and Nd at Bi{sup 3+} site. Analysis of MPMS-VSM magnetic hysteresis data reveals a further enhancement in magnetism in the Nd doped Bi{sub 0.9}Ca{sub 0.1}FeO{sub 3,} which is further explained by XPS characterization.

  9. The investigation of minoxidil-induced [Ca2+]i rises and non-Ca2+-triggered cell death in PC3 human prostate cancer cells.

    Science.gov (United States)

    Chen, I-Shu; Chou, Chiang-Ting; Liu, Yuan-Yuarn; Yu, Chia-Cheng; Liang, Wei-Zhe; Kuo, Chun-Chi; Shieh, Pochuen; Kuo, Daih-Huang; Chen, Fu-An; Jan, Chung-Ren

    2017-02-01

    Minoxidil is clinically used to prevent hair loss. However, its effect on Ca 2+ homeostasis in prostate cancer cells is unclear. This study explored the effect of minoxidil on cytosolic-free Ca 2+ levels ([Ca 2+ ] i ) and cell viability in PC3 human prostate cancer cells. Minoxidil at concentrations between 200 and 800 μM evoked [Ca 2+ ] i rises in a concentration-dependent manner. This Ca 2+ signal was inhibited by 60% by removal of extracellular Ca 2+ . Minoxidil-induced Ca 2+ influx was confirmed by Mn 2+ -induced quench of fura-2 fluorescence. Pre-treatment with the protein kinase C (PKC) inhibitor GF109203X, PKC activator phorbol 12-myristate 13 acetate (PMA), nifedipine and SKF96365 inhibited minoxidil-induced Ca 2+ signal in Ca 2+ containing medium by 60%. Treatment with the endoplasmic reticulum Ca 2+ pump inhibitor 2,5-ditert-butylhydroquinone (BHQ) in Ca 2+ -free medium abolished minoxidil-induced [Ca 2+ ] i rises. Conversely, treatment with minoxidil abolished BHQ-induced [Ca 2+ ] i rises. Inhibition of phospholipase C (PLC) with U73122 abolished minoxidil-evoked [Ca 2+ ] i rises. Overnight treatment with minoxidil killed cells at concentrations of 200-600 μM in a concentration-dependent fashion. Chelation of cytosolic Ca 2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid/AM (BAPTA/AM) did not prevent minoxidil's cytotoxicity. Together, in PC3 cells, minoxidil induced [Ca 2+ ] i rises that involved Ca 2+ entry through PKC-regulated store-operated Ca 2+ channels and PLC-dependent Ca 2+ release from the endoplasmic reticulum. Minoxidil-induced cytotoxicity in a Ca 2+ -independent manner.

  10. An inhibitory effect of extracellular Ca2+ on Ca2+-dependent exocytosis.

    Directory of Open Access Journals (Sweden)

    Wei Xiong

    Full Text Available AIM: Neurotransmitter release is elicited by an elevation of intracellular Ca(2+ concentration ([Ca(2+](i. The action potential triggers Ca(2+ influx through Ca(2+ channels which causes local changes of [Ca(2+](i for vesicle release. However, any direct role of extracellular Ca(2+ (besides Ca(2+ influx on Ca(2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG neurons and chromaffin cells, widely used models for studying vesicle exocytosis. RESULTS: Using photolysis of caged Ca(2+ and caffeine-induced release of stored Ca(2+, we found that extracellular Ca(2+ inhibited exocytosis following moderate [Ca(2+](i rises (2-3 µM. The IC(50 for extracellular Ca(2+ inhibition of exocytosis (ECIE was 1.38 mM and a physiological reduction (∼30% of extracellular Ca(2+ concentration ([Ca(2+](o significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca(2+](o. The calcimimetics Mg(2+, Cd(2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca(2+-sensing receptor (CaSR was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. CONCLUSION/SIGNIFICANCE: As an extension of the classic Ca(2+ hypothesis of synaptic release, physiological levels of extracellular Ca(2+ play dual roles in evoked exocytosis by providing a source of Ca(2+ influx, and by directly regulating quantal size and release probability in neuronal cells.

  11. Observation of microstructure of hydrated Ca3SiO5

    International Nuclear Information System (INIS)

    Mori, Kazuhiro; Sato, Takashi; Fukunaga, Toshiharu; Oishi, Koji; Kimura, Katsuhiko; Iwase, Kenji; Sugiyama, Masaaki; Itoh, Keiji; Shikanai, Fumihito; Wuernisha, Tuerxun; Yonemura, Masao; Sulistyanintyas, Dyah; Tsukushi, Itaru; Takata, Shinich; Otomo, Toshiya; Kamiyma, Takashi; Kawai, Masayoshi

    2006-01-01

    Quasi-elastic neutron scattering experiments were carried out to evaluate the hydration rate of tricalcium silicate (Ca 3 SiO 5 ). Furthermore, in the early hydration period, a variation in surface roughness of Ca 3 SiO 5 was observed in nano-scale by the small-angle neutron scattering. From these results, it was found that the hydration rate of Ca 3 SiO 5 is suppressed when the surface of Ca 3 SiO 5 becomes rough through the creation of hydration products C-S-H gel and Ca(OH) 2 , and this roughness is associated with changes in the Ca 3 SiO 5 hydration rate

  12. Mg and Ca isotope fractionation during CaCO3 biomineralisation

    International Nuclear Information System (INIS)

    Chang, Veronica T.-C.; Williams, R.J.P.; Makishima, Akio; Belshawl, Nick S.; O'Nions, R. Keith

    2004-01-01

    The natural variation of Mg and Ca stable isotopes of carbonates has been determined in carbonate skeletons of perforate foraminifera and reef coral together with Mg/Ca ratios to assess the influence of biomineralisation processes. The results for coral aragonite suggest its formation, in terms of stable isotope behaviour, approximates to inorganic precipitation from a seawater reservoir. In contrast, results for foraminifera calcite suggest a marked biological control on Mg isotope ratios presumably related to its low Mg content compared with seawater. The bearing of these observations on the use of Mg and Ca isotopes as proxies in paleoceanography is considered

  13. Regulation of the voltage-gated Ca2+ channel CaVα2δ-1 subunit expression by the transcription factor Egr-1.

    Science.gov (United States)

    González-Ramírez, Ricardo; Martínez-Hernández, Elizabeth; Sandoval, Alejandro; Gómez-Mora, Kimberly; Felix, Ricardo

    2018-04-23

    It is well known that the Ca V α 2 δ auxiliary subunit regulates the density of high voltage-activated Ca 2+ channels in the plasma membrane and that alterations in their functional expression might have implications in the pathophysiology of diverse human diseases such as neuropathic pain. However, little is known concerning the transcriptional regulation of this protein. We previously characterized the promoter of Ca V α 2 δ, and here we report its regulation by the transcription factor Egr-1. Using the neuroblastoma N1E-115 cells, we found that Egr-1 interacts specifically with its binding site in the promoter, affecting the transcriptional regulation of Ca V α 2 δ. Overexpression and knockdown analysis of Egr-1 showed significant changes in the transcriptional activity of the Ca V α 2 δ promoter. Egr-1 also regulated the expression of Ca V α 2 δ at the level of protein. Also, functional studies showed that Egr-1 knockdown significantly decreases Ca 2+ currents in dorsal root ganglion (DRG) neurons, while overexpression of the transcription factor increased Ca 2+ currents in the F11 cell line, a hybrid of DRG and N18TG2 neuroblastoma cells. Studying the effects of Egr-1 on the transcriptional expression of Ca V α 2 δ could help to understand the regulatory mechanisms of this protein in both health and disease. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Epigallocatechin-3-gallate increases intracellular [Ca2+] in U87 cells mainly by influx of extracellular Ca2+ and partly by release of intracellular stores.

    Science.gov (United States)

    Kim, Hee Jung; Yum, Keun Sang; Sung, Jong-Ho; Rhie, Duck-Joo; Kim, Myung-Jun; Min, Do Sik; Hahn, Sang June; Kim, Myung-Suk; Jo, Yang-Hyeok; Yoon, Shin Hee

    2004-02-01

    Green tea has been receiving considerable attention as a possible preventive agent against cancer and cardiovascular disease. Epigallocatechin-3-gallate (EGCG) is a major polyphenol component of green tea. Using digital calcium imaging and an assay for [3H]-inositol phosphates, we determined whether EGCG increases intracellular [Ca2+] ([Ca2+]i) in non-excitable human astrocytoma U87 cells. EGCG induced concentration-dependent increases in [Ca2+]i. The EGCG-induced [Ca2+]i increases were reduced to 20.9% of control by removal of extracellular Ca2+. The increases were also inhibited markedly by treatment with the non-specific Ca2+ channel inhibitors cobalt (3 mM) for 3 min and lanthanum (1 mM) for 5 min. The increases were not significantly inhibited by treatment for 10 min with the L-type Ca2+ channel blocker nifedipine (100 nM). Treatment with the inhibitor of endoplasmic reticulum Ca2+-ATPase thapsigargin (1 micro M) also significantly inhibited the EGCG-induced [Ca2+]i increases. Treatment for 15 min with the phospholipase C (PLC) inhibitor neomycin (300 micro M) attenuated the increases significantly, while the tyrosine kinase inhibitor genistein (30 micro M) had no effect. EGCG increased [3H]-inositol phosphates formation via PLC activation. Treatment for 10 min with mefenamic acid (100 micro M) and flufenamic acid (100 micro M), derivatives of diphenylamine-2-carboxylate, blocked the EGCG-induced [Ca2+]i increase in non-treated and thapsigargin-treated cells but indomethacin (100 micro M) did not affect the increases. Collectively, these data suggest that EGCG increases [Ca2+]i in non-excitable U87 cells mainly by eliciting influx of extracellular Ca2+ and partly by mobilizing intracellular Ca2+ stores by PLC activation. The EGCG-induced [Ca2+]i influx is mediated mainly through channels sensitive to diphenylamine-2-carboxylate derivatives.

  15. Infrared spectroscopic study of CaFe0.7Co0.3O3

    Science.gov (United States)

    Zhang, C. X.; Xia, H. L.; Dai, Y. M.; Qiu, Z. Y.; Sui, Q. T.; Long, Y. W.; Qiu, X. G.

    2017-08-01

    Temperature-dependent infrared spectroscopy has been investigated for CaFe0.7Co0.3O3 which undergoes a ferromagnetic transition at TC≈177 K . It is observed that the spectral weight is transferred from ˜4800 -14 000 cm-1 to ˜0 -4800 cm-1 as the temperature is lowered around TC. Such a large-range spectral weight transfer is attributed to the Hund's interaction. The phonons in CaFe0.7Co0.3O3 show minor asymmetric line shapes, implying relatively weak electron-phonon coupling compared with the parent compound CaFeO3. The optical conductivity also reveals a broad peak structure in the range of ˜700 -1500 cm-1. Fit by the model of single-polaron absorption, the broad peak is interpreted by the excitation of polarons. From the fitting parameters of the polaron peak, we estimate the electron-phonon coupling constant α ˜ 0.4 -0.5 , implying that CaFe0.7Co0.3O3 falls into the weak-coupling regime.

  16. Epitaxial growth of lithium fluoride on the (1 1 1) surface of CaF 2

    Science.gov (United States)

    Klumpp, St; Dabringhaus, H.

    1999-08-01

    Growth of lithium fluoride by molecular beam epitaxy on the (1 1 1) surface of calcium fluoride crystals was studied by TEM and LEED for crystal temperatures from 400 to 773 K and impinging lithium fluoride fluxes from 3×10 11 to 3×10 14 cm -2 s -1. Growth starts, usually, at the steps on the (1 1 1) surface of CaF 2. For larger step distances and at later growth stages also growth on the terraces between the steps is found. Preferably, longish, roof-like crystallites are formed, which can be interpreted by growth of LiF(2 0 1¯)[0 1 0] parallel to CaF 2(1 1 1)[ 1¯ 0 1]. To a lesser extent square crystallites, i.e. growth with LiF(0 0 1), and, rarely, three-folded pyramidal crystallites, i.e. growth with LiF(1 1 1) parallel to CaF 2(1 1 1), are observed. While the pyramidal crystallites show strict epitaxial orientation with LiF[ 1¯ 0 1]‖CaF 2[ 1¯ 0 1] and LiF[ 1¯ 0 1]‖CaF 2[11], only about 80% of the square crystallites exhibit an epitaxial alignment, where LiF[1 0 0]‖CaF 2[ 1¯ 0 1] is preferred to LiF[1 1 0]‖CaF 2[ 1¯ 0 1]. The epitaxial relationships are discussed on the basis of theoretically calculated adsorption positions of the lithium fluoride monomer and dimer on the terrace and at the steps of the CaF 2(1 1 1) surface.

  17. Troponin T3 regulates nuclear localization of the calcium channel Ca{sub v}β{sub 1a} subunit in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tan; Taylor, Jackson; Jiang, Yang [Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States); Pereyra, Andrea S. [Department of Histology, National University of La Plata, 1900 La Plata (Argentina); Messi, Maria Laura; Wang, Zhong-Min [Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States); Hereñú, Claudia [Department of Histology, National University of La Plata, 1900 La Plata (Argentina); Delbono, Osvaldo, E-mail: odelbono@wakehealth.edu [Department of Internal Medicine-Gerontology, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States); Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, NC 27157 (United States)

    2015-08-15

    The voltage-gated calcium channel (Ca{sub v}) β{sub 1a} subunit (Ca{sub v}β{sub 1a}) plays an important role in excitation–contraction coupling (ECC), a process in the myoplasm that leads to muscle-force generation. Recently, we discovered that the Ca{sub v}β{sub 1a} subunit travels to the nucleus of skeletal muscle cells where it helps to regulate gene transcription. To determine how it travels to the nucleus, we performed a yeast two-hybrid screening of the mouse fast skeletal muscle cDNA library and identified an interaction with troponin T3 (TnT3), which we subsequently confirmed by co-immunoprecipitation and co-localization assays in mouse skeletal muscle in vivo and in cultured C2C12 muscle cells. Interacting domains were mapped to the leucine zipper domain in TnT3 COOH-terminus (160–244 aa) and Ca{sub v}β{sub 1a} NH{sub 2}-terminus (1–99 aa), respectively. The double fluorescence assay in C2C12 cells co-expressing TnT3/DsRed and Ca{sub v}β{sub 1a}/YFP shows that TnT3 facilitates Ca{sub v}β{sub 1a} nuclear recruitment, suggesting that the two proteins play a heretofore unknown role during early muscle differentiation in addition to their classical role in ECC regulation. - Highlights: • Previously, we demonstrated that Ca{sub v}β{sub 1a} is a gene transcription regulator. • Here, we show that TnT3 interacts with Ca{sub v}β{sub 1a}. • We mapped TnT3 and Ca{sub v}β{sub 1a} interaction domain. • TnT3 facilitates Ca{sub v}β{sub 1a} nuclear enrichment. • The two proteins play a heretofore unknown role during early muscle differentiation.

  18. Apo-states of calmodulin and CaBP1 control CaV1 voltage-gated calcium channel function through direct competition for the IQ domain

    Science.gov (United States)

    Findeisen, Felix; Rumpf, Christine; Minor, Daniel L.

    2013-01-01

    In neurons, binding of calmodulin (CaM) or calcium-binding protein 1 (CaBP1) to the CaV1 (L-type) voltage-gated calcium channel IQ domain endows the channel with diametrically opposed properties. CaM causes calcium-dependent inactivation (CDI) and limits calcium entry, whereas CaBP1 blocks CDI and allows sustained calcium influx. Here, we combine isothermal titration calorimetry (ITC) with cell-based functional measurements and mathematical modeling to show that these calcium sensors behave in a competitive manner that is explained quantitatively by their apo-state binding affinities for the IQ domain. This competition can be completely blocked by covalent tethering of CaM to the channel. Further, we show that Ca2+/CaM has a sub-picomolar affinity for the IQ domain that is achieved without drastic alteration of calcium binding properties. The observation that the apo-forms of CaM and CaBP1 compete with each other demonstrates a simple mechanism for direct modulation of CaV1 function and suggests a means by which excitable cells may dynamically tune CaV activity. PMID:23811053

  19. Apo states of calmodulin and CaBP1 control CaV1 voltage-gated calcium channel function through direct competition for the IQ domain.

    Science.gov (United States)

    Findeisen, Felix; Rumpf, Christine H; Minor, Daniel L

    2013-09-09

    In neurons, binding of calmodulin (CaM) or calcium-binding protein 1 (CaBP1) to the CaV1 (L-type) voltage-gated calcium channel IQ domain endows the channel with diametrically opposed properties. CaM causes calcium-dependent inactivation and limits calcium entry, whereas CaBP1 blocks calcium-dependent inactivation (CDI) and allows sustained calcium influx. Here, we combine isothermal titration calorimetry with cell-based functional measurements and mathematical modeling to show that these calcium sensors behave in a competitive manner that is explained quantitatively by their apo-state binding affinities for the IQ domain. This competition can be completely blocked by covalent tethering of CaM to the channel. Further, we show that Ca(2+)/CaM has a sub-picomolar affinity for the IQ domain that is achieved without drastic alteration of calcium-binding properties. The observation that the apo forms of CaM and CaBP1 compete with each other demonstrates a simple mechanism for direct modulation of CaV1 function and suggests a means by which excitable cells may dynamically tune CaV activity. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. 2:1 Charge disproportionation in perovskite-structure oxide La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+}

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Haichuan; Hosaka, Yoshiteru; Seki, Hayato; Saito, Takashi; Ichikawa, Noriya [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Shimakawa, Yuichi, E-mail: shimak@scl.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Integrated Research Consortium on Chemical Sciences, Uji, Kyoto 611-0011 (Japan)

    2017-02-15

    La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} was synthesized at a high pressure and high temperature. The compound crystallizes in a √2a×2a×√2a perovskite cell in which the La and Ca ions at the A site are disordered. At 217 K the Fe{sup 3.67+} shows charge disproportionation to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1, and this disproportionation is accompanied by transitions in magnetic and transport properties. The charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. The local electronic and magnetic environments of Fe in La{sub 1/3}Ca{sub 2/3}FeO{sub 3} are quite similar to those of Fe in La{sub 1/3}Sr{sub 2/3}FeO{sub 3}, and the 2:1 charge disproportionation pattern of Fe{sup 3+} and Fe{sup 5+} in La{sub 1/3}Ca{sub 2/3}FeO{sub 3} is also the same as that in La{sub 1/3}Sr{sub 2/3}FeO{sub 3}. - Graphical abstract: The perovskite-structure oxide La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} shows charge disproportionation to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1, and the charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. - Highlights: • La{sub 1/3}Ca{sub 2/3}FeO{sub 3} with unusually-high-valence Fe{sup 3.67+} was synthesized at a high pressure and high temperature. • At 217 K the Fe{sup 3.67+} shows charge disproportionation (CD) to Fe{sup 3+} and Fe{sup 5+} in a ratio of 2:1. • The charge-disproportionated Fe{sup 3+} and Fe{sup 5+} are arranged along the <111> direction of the cubic perovskite cell. • The disproportionation is accompanied by transitions in magnetic and transport properties.

  1. Stochastic simulation of a single inositol 1,4,5-trisphosphate-sensitive Ca2+ channel reveals repetitive openings during 'blip-like' Ca2+ transients.

    Science.gov (United States)

    Swillens, S; Champeil, P; Combettes, L; Dupont, G

    1998-05-01

    Confocal microscope studies with fluorescent dyes of inositol 1,4,5-trisphosphate (InsP3)-induced intracellular Ca2+ mobilization recently established the existence of 'elementary' events, dependent on the activity of individual InsP3-sensitive Ca2+ channels. In the present work, we try by theoretical stochastic simulation to explain the smallest signals observed in those studies, which were referred to as Ca2+ 'blips' [Parker I., Yao Y. Ca2+ transients associated with openings of inositol trisphosphate-gated channels in Xenopus oocytes. J Physiol Lond 1996; 491: 663-668]. For this purpose, we assumed a simple molecular model for the InsP3-sensitive Ca2+ channel and defined a set of parameter values accounting for the results obtained in electrophysiological bilayer experiments [Bezprozvanny I., Watras J., Ehrlich B.E. Bell-shaped calcium-response curves of Ins(1,4,5)P3- and calcium-gated channels from endoplasmic reticulum of cerebellum. Nature 1991; 351: 751-754; Bezprozvanny I., Ehrlich B.E. Inositol (1,4,5)-trisphosphate (InsP3)-gated Ca channels from cerebellum: conduction properties for divalent cations and regulation by intraluminal calcium. J Gen Physiol 1994; 104: 821-856]. With a stochastic procedure which considered cytosolic Ca2+ diffusion explicitly, we then simulated the behaviour of a single channel, placed in a realistic physiological environment. An attractive result was that the simulated channel exhibited bursts of activity, arising from repetitive channel openings, which were responsible for transient rises in Ca2+ concentration and were reminiscent of the relatively long-duration experimental Ca2+ blips. The influence of the values chosen for the various parameters (affinity and diffusion coefficient of the buffers, luminal Ca2+ concentration) on the kinetic characteristics of these theoretical blips is analyzed.

  2. Solidification of Bi2Sr2Ca1Cu2Oy and Bi2Sr1.75Ca0.25CuOy

    International Nuclear Information System (INIS)

    Holesinger, T.G.; Miller, D.J.; Viswanathan, H.K.; Chumbley, L.S.

    1993-01-01

    The solidification processes for the compositions Bi 2 Sr 2 CaCu 2 O y (2212) and Bi 2 Sr 1.75 Ca 0.25 CuO y (2201) were determined as a function of oxygen partial pressure. During solidification in argon, the superconducting phases were generally not observed to form for either composition. In both cases, the solidus is lowered to approximately 750 degree C. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 2-x Ca x O y (22x) and Cu 2 O while solidification of Bi 2 Sr 2 CaCu 2 O y in Ar resulted in a divorced eutectic structure of Bi 2 Sr 3-x Ca x O y (23x) and Cu 2 O. Solidification of Bi 2 Sr 1.75 Ca 0.25 CuO y in O 2 resulted in large grains of 2201 interspersed with small regions containing the eutectic structure of 22x and CuO/Cu 2 O. Solidification of Bi 2 Sr 2 CaCu 2 O y in partial pressures of 1%, 20%, and 100% oxygen resulted in multiphase samples consisting of 2212, 2201, some alkaline-earth cuprates, and both divorced eutectic structures found during solidification in Ar. For both compositions, these latter structures can be attributed to oxygen deficiencies present in the melt regardless of the overpressure of oxygen. These eutectic structures are unstable and convert into the superconducting phases during subsequent anneals in oxygen. The formation process of the 2212 phase during solidification from the melt was determined to proceed through an intermediate state involving the 2201 phase

  3. The system La(PO3)3-Ca(PO3)2-P2O5

    International Nuclear Information System (INIS)

    Jungowska, W.; Znamierowska, T.

    1993-01-01

    Ternary system La(PO 3 ) 3 -Ca(PO 3 ) 2 -P 2 O 5 has been studied by means of thermal and roentgenography analysis. The existence of single intermediate compound CaLa(PO 3 ) 5 has been observed. The phase diagrams for the ternary system as well as for two binary systems La(PO 3 ) 3 -Ca(PO 3 ) 2 and CaLa(PO 3 ) 5 -LaP 5 O 11 have been shown. 7 refs, 3 figs

  4. Gene of the month: PIK3CA.

    Science.gov (United States)

    Lai, K; Killingsworth, M C; Lee, C S

    2015-04-01

    PIK3CA encodes the p110α catalytic subunit of phosphatidylinositol 3-kinase (PI3K) which through its role in the PI3K/Akt pathway is important for the regulation of important cellular functions such as proliferation, metabolism and protein synthesis, angiogenesis and apoptosis. Mutations in PIK3CA are known to be involved in a wide range of human cancers and mutant PIK3CA is thought to act as an oncogene. The specific PIK3CA inhibitor, NVP-BYL719, has displayed promising results in cancer therapy and is currently under clinical trials. Furthermore, PI3K regulates autophagy, a cellular process that recycles proteins and organelles through lysosomal degradation and has recently been recognised as an attractive therapeutic target due to its pro- and anti-cancer properties. Several studies have attempted to investigate the effects of combining the inhibition of both PI3K and autophagy in cancer therapy, and an in vivo model has demonstrated that the combined use of a concomitant PI3K and autophagy inhibitor induced apoptosis in glioma cells. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  5. Positive Feedback Regulation of Agonist-Stimulated Endothelial Ca2+ Dynamics by KCa3.1 Channels in Mouse Mesenteric Arteries

    DEFF Research Database (Denmark)

    Qian, Xun; Francis, Michael; Köhler, Ralf

    2014-01-01

    Intermediate and small conductance KCa channels IK1 (KCa3.1) and SK3 (KCa2.3) are primary targets of endothelial Ca(2+) signals in the arterial vasculature, and their ablation results in increased arterial tone and hypertension. Activation of IK1 channels by local Ca(2+) transients from internal ...... stores or plasma membrane channels promotes arterial hyperpolarization and vasodilation. Here, we assess arteries from genetically altered IK1 knockout mice (IK1(-/-)) to determine whether IK1 channels exert a positive feedback influence on endothelial Ca(2+) dynamics....

  6. Luminescence and energy transfer of Sm3+ and Eu3+ in Ca2PO4Cl

    International Nuclear Information System (INIS)

    Wang, Zhijun; Li, Panlai; Yang, Zhiping; Guo, Qinglin

    2014-01-01

    Sm 3+ , Eu 3+ , and Sm 3+ –Eu 3+ doped Ca 2 PO 4 Cl phosphors are synthesized by a solid-state method. Ca 2 PO 4 Cl:Sm 3+ can produce red emission under the 400 nm radiation excitation, and the emission peak is located at 601 nm, which is assigned to the 4 G 5/2 → 6 H 7/2 transition of Sm 3+ . Ca 2 PO 4 Cl:Eu 3+ can create red emission under the 392 nm radiation excitation, and the strongest peak is located at 620 nm, which is attributed to the 5 D 0 → 7 F 2 transition of Eu 3+ . The energy transfer from Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl has been validated and the critical distance (R c ) of Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl is calculated to be 1.14 nm. With increasing Eu 3+ doping concentration, the energy transfer efficiency (Sm 3+ →Eu 3+ ) gradually increases to 53.7%. The luminescence property of Ca 2 PO 4 Cl:Sm 3+ , Eu 3+ can be tuned by properly tuning the relative ratio of Sm 3+ –Eu 3+ , and the emission intensity of Ca 2 PO 4 Cl:Eu 3+ can be greatly enhanced by codoped Sm 3+ . - Highlights: • Ca 2 PO 4 Cl:Sm 3+ , Eu 3+ can produce red emission under the 400 nm radiation excitation. • The energy transfer from Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl has been validated. • The critical distance of Sm 3+ to Eu 3+ in Ca 2 PO 4 Cl is calculated to be 1.14 nm

  7. Physiological and Pathological Roles of CaMKII-PP1 Signaling in the Brain

    Directory of Open Access Journals (Sweden)

    Norifumi Shioda

    2017-12-01

    Full Text Available Ca2+/calmodulin (CaM-dependent protein kinase II (CaMKII, a multifunctional serine (Ser/threonine (Thr protein kinase, regulates diverse activities related to Ca2+-mediated neuronal plasticity in the brain, including synaptic activity and gene expression. Among its regulators, protein phosphatase-1 (PP1, a Ser/Thr phosphatase, appears to be critical in controlling CaMKII-dependent neuronal signaling. In postsynaptic densities (PSDs, CaMKII is required for hippocampal long-term potentiation (LTP, a cellular process correlated with learning and memory. In response to Ca2+ elevation during hippocampal LTP induction, CaMKIIα, an isoform that translocates from the cytosol to PSDs, is activated through autophosphorylation at Thr286, generating autonomous kinase activity and a prolonged Ca2+/CaM-bound state. Moreover, PP1 inhibition enhances Thr286 autophosphorylation of CaMKIIα during LTP induction. By contrast, CaMKII nuclear import is regulated by Ser332 phosphorylation state. CaMKIIδ3, a nuclear isoform, is dephosphorylated at Ser332 by PP1, promoting its nuclear translocation, where it regulates transcription. In this review, we summarize physio-pathological roles of CaMKII/PP1 signaling in neurons. CaMKII and PP1 crosstalk and regulation of gene expression is important for neuronal plasticity as well as survival and/or differentiation.

  8. Dentate network activity is necessary for spatial working memory by supporting CA3 sharp-wave ripple generation and prospective firing of CA3 neurons.

    Science.gov (United States)

    Sasaki, Takuya; Piatti, Verónica C; Hwaun, Ernie; Ahmadi, Siavash; Lisman, John E; Leutgeb, Stefan; Leutgeb, Jill K

    2018-02-01

    Complex spatial working memory tasks have been shown to require both hippocampal sharp-wave ripple (SWR) activity and dentate gyrus (DG) neuronal activity. We therefore asked whether DG inputs to CA3 contribute to spatial working memory by promoting SWR generation. Recordings from DG and CA3 while rats performed a dentate-dependent working memory task on an eight-arm radial maze revealed that the activity of dentate neurons and the incidence rate of SWRs both increased during reward consumption. We then found reduced reward-related CA3 SWR generation without direct input from dentate granule neurons. Furthermore, CA3 cells with place fields in not-yet-visited arms preferentially fired during SWRs at reward locations, and these prospective CA3 firing patterns were more pronounced for correct trials and were dentate-dependent. These results indicate that coordination of CA3 neuronal activity patterns by DG is necessary for the generation of neuronal firing patterns that support goal-directed behavior and memory.

  9. Low-Temperature Sintering Li3Mg1.8Ca0.2NbO6 Microwave Dielectric Ceramics with LMZBS Glass

    Science.gov (United States)

    Wang, Gang; Zhang, Huaiwu; Liu, Cheng; Su, Hua; Jia, Lijun; Li, Jie; Huang, Xin; Gan, Gongwen

    2018-05-01

    Li3Mg1.8Ca0.2NbO6 ceramics doped with Li2O-MgO-ZnO-B2O3-SiO2 glass (LMZBS) were prepared via a solid-state route. The LMZBS glass effectively reduced the sintering temperature of Li3Mg1.8Ca0.2NbO6 ceramics to 950°C. The effects of the LMZBS glass on the sintering behavior, microstructures and microwave dielectric properties of Li3Mg1.8Ca0.2NbO6 ceramics are discussed in detail. Among all the LMZBS doped Li3Mg1.8Ca0.2NbO6 ceramics, the sample with 1 wt.% of LMZBS glass sintered at 950°C for 4 h exhibited good dielectric properties: ɛ r = 16.7, Q × f = 31,000 GHz (9.92 GHz), τ f = - 1.3 ppm/°C. The Li3Mg1.8Ca0.2NbO6 ceramics possessed excellent chemical compatibility with Ag electrodes, and could be applied in low temperature co-fired ceramics (LTCC) applications.

  10. La 1-x Ca x MnO 3 semiconducting nanostructures: morphology and thermoelectric properties.

    Science.gov (United States)

    Culebras, Mario; Torán, Raquel; Gómez, Clara M; Cantarero, Andrés

    2014-01-01

    Semiconducting metallic oxides, especially perosvkite materials, are great candidates for thermoelectric applications due to several advantages over traditionally metallic alloys such as low production costs and high chemical stability at high temperatures. Nanostructuration can be the key to develop highly efficient thermoelectric materials. In this work, La 1-x Ca x MnO 3 perosvkite nanostructures with Ca as a dopant have been synthesized by the hydrothermal method to be used in thermoelectric applications at room temperature. Several heat treatments have been made in all samples, leading to a change in their morphology and thermoelectric properties. The best thermoelectric efficiency has been obtained for a Ca content of x=0.5. The electrical conductivity and Seebeck coefficient are strongly related to the calcium content.

  11. Effects of 45Ca on murine skeletal muscle. 3

    International Nuclear Information System (INIS)

    Malhotra, R.K.; Asotra, K.; Katoch, S.S.; Krishan, K.

    1983-01-01

    Swiss albino mice were injected intraperitoneally with 3.7x10 4 Bq and 7.4x10 4 Bq 45 Ca/g body weight. Mice of both dose groups were autopsied on days 1, 3, 5, 7, 14 and 28 and activities of alanine aminotransferase and aspartate aminotransferase bioassayed in diaphragm and gastrocnemius in 45 Ca-treated and normal mice. Alanine aminotransferase activity in the two muscles increased in response to 45 Ca administration suggesting a stepped up utilization of alanine in glucose generation. Aspartate aminotransferase levels, on the other hand, diminished in both the 45 Ca-treated muscles and are maintained at low values throughout the 28 day period of study. The results suggest an innate ability of skeletal muscle to selectively utilize either of the two glucogenic amino acids during radiation stress. The data are discussed in light of previous findings on glycogen accumulation in irradiated skeletal muscle. (author)

  12. Enhanced magnetoresistance in La0.7Ca0.3Mn03/Nd0.7Ca0.3Mn03 epitaxial multilayers

    International Nuclear Information System (INIS)

    Sharma, Himanshu; Khan, Md. S.; Tomy, C.V.; Jain, Sourabh; Tulapurkar, Ashwin

    2014-01-01

    Magnanite multilayers of La 0.7 Ca 0.3 MnO 3 /Nd 0.7 Ca 0.5 MnO 3 have been fabricated on SrTiO 3 (100) substrate using Nd 0.7 Ca 0.5 MnO 3 as the spacer layers. An enhanced magnetoresistance (MR) of more than 80% is observed in the multilayers compared with LCMO thin film (∼50%). Result suggests that the interface strains between LCMO and NCMO layers may have influences on the transport properties and a suitable film structure could be used to increase the large low field magnetoresistance. (author)

  13. Ablation of Ca(V)2.1 voltage-gated Ca²⁺ channels in mouse forebrain generates multiple cognitive impairments.

    Science.gov (United States)

    Mallmann, Robert Theodor; Elgueta, Claudio; Sleman, Faten; Castonguay, Jan; Wilmes, Thomas; van den Maagdenberg, Arn; Klugbauer, Norbert

    2013-01-01

    Voltage-gated Ca(V)2.1 (P/Q-type) Ca²⁺ channels located at the presynaptic membrane are known to control a multitude of Ca²⁺-dependent cellular processes such as neurotransmitter release and synaptic plasticity. Our knowledge about their contributions to complex cognitive functions, however, is restricted by the limited adequacy of existing transgenic Ca(V)2.1 mouse models. Global Ca(V)2.1 knock-out mice lacking the α1 subunit Cacna1a gene product exhibit early postnatal lethality which makes them unsuitable to analyse the relevance of Ca(V)2.1 Ca²⁺ channels for complex behaviour in adult mice. Consequently we established a forebrain specific Ca(V)2.1 knock-out model by crossing mice with a floxed Cacna1a gene with mice expressing Cre-recombinase under the control of the NEX promoter. This novel mouse model enabled us to investigate the contribution of Ca(V)2.1 to complex cognitive functions, particularly learning and memory. Electrophysiological analysis allowed us to test the specificity of our conditional knock-out model and revealed an impaired synaptic transmission at hippocampal glutamatergic synapses. At the behavioural level, the forebrain-specific Ca(V)2.1 knock-out resulted in deficits in spatial learning and reference memory, reduced recognition memory, increased exploratory behaviour and a strong attenuation of circadian rhythmicity. In summary, we present a novel conditional Ca(V)2.1 knock-out model that is most suitable for analysing the in vivo functions of Ca(V)2.1 in the adult murine forebrain.

  14. SNAP-25 in hippocampal CA3 region is required for long-term memory formation

    International Nuclear Information System (INIS)

    Hou Qiuling; Gao Xiang; Lu Qi; Zhang Xuehan; Tu Yanyang; Jin Meilei; Zhao Guoping; Yu Lei; Jing Naihe; Li Baoming

    2006-01-01

    SNAP-25 is a synaptosomal protein of 25 kDa, a key component of synaptic vesicle-docking/fusion machinery, and plays a critical role in exocytosis and neurotransmitter release. We previously reported that SNAP-25 in the hippocampal CA1 region is involved in consolidation of contextual fear memory and water-maze spatial memory (Hou et al. European J Neuroscience, 20: 1593-1603, 2004). SNAP-25 is expressed not only in the CA1 region, but also in the CA3 region, and the SNAP-25 mRNA level in the CA3 region is higher than in the CA1 region. Here, we provide evidence that SNAP-25 in the CA3 region is also involved in learning/memory. Intra-CA3 infusion of SNAP-25 antisense oligonucleotide impaired both long-term contextual fear memory and water-maze spatial memory, with short-term memory intact. Furthermore, the SNAP-25 antisense oligonucleotide suppressed the long-term potentiation (LTP) of field excitatory post-synaptic potential (fEPSP) in the mossy-fiber pathway (DG-CA3 pathway), with no effect on paired-pulse facilitation of the fEPSP. These results are consistent with the notion that SNAP-25 in the hippocampal CA3 region is required for long-term memory formation

  15. 1,25 (OH)2 vitamin D3-induced 45Ca uptake in vascular myocytes cultured from spontaneously hypertensive and normotensive rats

    International Nuclear Information System (INIS)

    Xue, Hong; McCarron, D.A.; Bukoski, R.D.

    1991-01-01

    The effect of 1,25 (OH) 2 vitamin D 3 on basal 45 Ca uptake was examined in vasvular smooth muscle cells cultured from mesenteric arteries of spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) normotensive rats. Basal uptake of 45 Ca was significantly greater in myocytes of WKY than SHR at 5, 10, 30 and 60 min incubation with the isotope. Incubation with 1 ng/ml 1,25 (OH) 2 vitamin D 3 for 48 hr increased basal 45 Ca uptake between 1-10 min in SHR and between 5-10 min in WKY. The dose-response relationship indicated that cells from both strains are equally sensitive to the calciotropic effects of 1,25 (OH) 2 vitamin D 3 with half-maximal stimulation occurring at approximately 0.3-0.4 ng/ml. In cells of both strains maximal stimulation of 45 Ca uptake was achieved only after a 12-24 hr period of incubation with hormone and pretreatment with cycloheximide inhibited 1,24 (OH) 2 vitamin D 3 -enhanced 45 Ca uptake. Although 45 Ca binding by extracellular matrix material was significantly greater in WKY than SHR, 1,25 (OH) 2 vitamin D 3 had no effect on the amount of matrix 45 Ca binding in either strain

  16. Spin decomposition of the responses of 44Ca and 48Ca to 300 MeV protons

    International Nuclear Information System (INIS)

    Baker, F.T.; Bimbot, L.; Fergerson, R.W.; Glashausser, C.; Green, A.; Haeusser, O.; Hicks, K.; Jones, K.; Miller, C.A.; Vetterli, M.; Abegg, R.; Beatty, D.; Bonin, B.; Castel, B.; Chen, X.Y.; Cupps, V.; Djalali, C.; Henderson, R.; Jackson, K.P.; Jeppesen, R.; Nakayama, K.; Nanda, S.K.; Sawafta, R.; Yen, S.; Institut de Physique Nucleaire, F-91406 Orsay, France; Rutgers University, Piscataway, New Jersey 08854; Simon Fraser University, Burnaby, Canada V5A1S6; TRIUMF, 4004 Westbrook Mall, Vancouver, Canada V6T2A3; Los Alamos National Laboratory, Los Alamos, New Mexico 87544; Centre d'Etudes Nucleaires de Saclay, 91191 Gif sur Yvette, CEDEX, France; Queen's University, Kingston, Canada K7L3N6; University of Colorado, Boulder, Colorado 80309; University of South Carolina, Columbia, South Carolina 29208; Continuous Electron Beam Accelerator Facility, 12000 Jefferson Ave., Newport News, Virginia 23606; University of Alberta, Edmonton, Canada T6G2J1)

    1991-01-01

    Angular distributions of the double-differential cross section d 2 σ/dΩ dE(σ) and the spin-flip probability S nn have been measured for inclusive proton inelastic scattering from 44 Ca at 290 MeV and from 48 Ca at 318 MeV. Excitation energies up to about 50 MeV for 44 Ca and 40 MeV for 48 Ca have been investigated over the laboratory angular ranges of 3 degree to 12 degree for 44 Ca and 3 degree to 9 degree for 48 Ca. Multipole decompositions of angular distributions of both the spin-flip cross section σS nn and the estimated cross section for ΔS=0 transitions have been performed. Distributions of strengths were deduced for ΔL=1, ΔS=0 (the giant dipole), ΔL=2, ΔS=0 (the giant quadrupole), ΔL=0, ΔS=1 (the magnetic dipole), ΔL=1, ΔS=1 (the spin dipole), and ΔL=2, ΔS=1 (the spin quadrupole). The ΔS=0 summed strengths for 44 Ca are lower than for 40 Ca and 48 Ca. The spin-dipole summed strengths are found to be approximately independent of A. For 48 Ca, essentially all M1 strength observed was in the 10.23 MeV 1 + state; for 44 Ca, M1 strength was observed to be fragmented over a range of 7 to 18 Mev

  17. Microstructure and electric characteristics of AETiO3 (AE=Mg, Ca, Sr doped CaCu3Ti4O12 thin films prepared by the sol–gel method

    Directory of Open Access Journals (Sweden)

    Dong Xu

    2015-10-01

    Full Text Available This paper focuses on the effects of alkline-earth metal titante AETiO3 (AE=Mg, Ca, Sr doping on the microstructure and electric characteristics of CaCu3Ti4O12 thin films prepared by the sol–gel method. The results showed that the grain size of CCTO thin films could be increased by MgTiO3 doping. The movement of the grain boundaries was impeded by the second phases of CaTiO3 and SrTiO3 concentrating at grain boundaries in CaTiO3 and SrTiO3 doped CCTO thin films. Rapid ascent of dielectric constant could be observed in 0.1Mg TiO3 doped CCTO thin films, which was almost as three times high as pure CCTO thin film and the descent of the dielectric loss at low frequency could also be observed. In addition, the nonlinear coefficient (α, threshold voltage (VT and leakage current (IL of AETiO3 doped CCTO thin films (AE=Mg, Ca, Sr showed different variation with the increasing content of the MgTiO3, CaTiO3 and SrTiO3.

  18. Protein Kinase Cα and P-Type Ca2+ Channel CaV2.1 in Red Blood Cell Calcium Signalling

    Directory of Open Access Journals (Sweden)

    Lisa Wagner-Britz

    2013-06-01

    Full Text Available Background/Aims: Protein kinase Cα (PKCα is activated by an increase in cytosolic Ca2+ in red blood cells (RBCs. Previous work has suggested that PKCα directly stimulates the CaV2.1 channel, whereas other studies revealed that CaV2.1 is insensitive to activation by PKC. The aim of this study was to resolve this discrepancy. Methods: We performed experiments based on a single cell read-out of the intracellular Ca2+ concentration in terms of Fluo-4 fluorescence intensity and phosphatidylserine exposure to the external membrane leaflet. Measurement modalities included flow cytometry and live cell imaging. Results: Treatment of RBCs with phorbol 12-myristate 13-acetate (PMA led to two distinct populations of cells with an increase in intracellular Ca2+: a weak-responding and a strong-responding population. The EC50 of PMA for the number of cells with Ca2+ elevation was 2.7±1.2 µM; for phosphatidylserine exposure to the external membrane surface, it was 2.8±0.5 µM; and for RBC haemolysis, it was 2.9±0.5 µM. Using pharmacological manipulation with the CaV2.1 inhibitor ω-agatoxin TK and the broad protein kinase C inhibitor Gö6983, we are able to show that there are two independent PMA-activated Ca2+ entry processes: the first is independent of CaV2.1 and directly PKCα-activated, while the second is associated with a likely indirect activation of CaV2.1. Further studies using lysophosphatidic acid (LPA as a stimulation agent have provided additional evidence that PKCα and CaV2.1 are not directly interconnected in a signalling chain. Conclusion: Although we provide evidence for a lack of interaction between PKCα and CaV2.1 in RBCs, further studies are required to decipher the signalling relationship between LPA, PKCα and CaV2.1.

  19. Ca2+/cation antiporters (CaCA: Identification, characterization and expression profiling in bread wheat (Triticum aestivum L.

    Directory of Open Access Journals (Sweden)

    Mehak Taneja

    2016-11-01

    Full Text Available The Ca2+/cation antiporters (CaCA superfamily proteins play vital function in Ca2+ ion homeostasis, which is an important event during development and defense response. Molecular characterization of these proteins has been performed in certain plants, but they are still not characterized in Triticum aestivum (bread wheat. Herein, we identified thirty four TaCaCA superfamily proteins, which were classified into TaCAX, TaCCX, TaNCL and TaMHX protein families based on their structural organization and evolutionary relation with earlier reported proteins. Since the T. aestivum comprises an allohexaploid genome, TaCaCA genes were derived from each A, B and D subgenome and homeologous chromosome (HC, except chromosome-group 1. Majority of genes were derived from more than one HCs in each family that were considered as homeologous genes (HGs due to their high similarity with each other. These HGs showed comparable gene and protein structures in terms of exon/intron organization and domain architecture. Majority of TaCaCA proteins comprised two Na_Ca_ex domains. However, TaNCLs consisted of an additional EF-hand domain with calcium binding motifs. Each TaCaCA protein family consisted of about ten transmembrane and two α-repeat regions with specifically conserved signature motifs except TaNCL, which had single α-repeat. Variable expression of most of the TaCaCA genes during various developmental stages suggested their specified role in development. However, constitutively high expression of a few genes like TaCAX1-A and TaNCL1-B indicated their role throughout the plant growth and development. The modulated expression of certain genes during biotic (fungal infections and abiotic stresses (heat, drought, salt suggested their role in stress response. Majority of TaCCX and TaNCL family genes were found highly affected during various abiotic stresses. However the role of individual gene needs to be established. The present study unfolded the opportunity

  20. Ca2+/Cation Antiporters (CaCA): Identification, Characterization and Expression Profiling in Bread Wheat (Triticum aestivum L.).

    Science.gov (United States)

    Taneja, Mehak; Tyagi, Shivi; Sharma, Shailesh; Upadhyay, Santosh Kumar

    2016-01-01

    The Ca 2+ /cation antiporters (CaCA) superfamily proteins play vital function in Ca 2+ ion homeostasis, which is an important event during development and defense response. Molecular characterization of these proteins has been performed in certain plants, but they are still not characterized in Triticum aestivum (bread wheat). Herein, we identified 34 TaCaCA superfamily proteins, which were classified into TaCAX, TaCCX, TaNCL, and TaMHX protein families based on their structural organization and evolutionary relation with earlier reported proteins. Since the T. aestivum comprises an allohexaploid genome, TaCaCA genes were derived from each A, B, and D subgenome and homeologous chromosome (HC), except chromosome-group 1. Majority of genes were derived from more than one HCs in each family that were considered as homeologous genes (HGs) due to their high similarity with each other. These HGs showed comparable gene and protein structures in terms of exon/intron organization and domain architecture. Majority of TaCaCA proteins comprised two Na_Ca_ex domains. However, TaNCLs consisted of an additional EF-hand domain with calcium binding motifs. Each TaCaCA protein family consisted of about 10 transmembrane and two α-repeat regions with specifically conserved signature motifs except TaNCL, which had single α-repeat. Variable expression of most of the TaCaCA genes during various developmental stages suggested their specified role in development. However, constitutively high expression of a few genes like TaCAX1-A and TaNCL1-B indicated their role throughout the plant growth and development. The modulated expression of certain genes during biotic (fungal infections) and abiotic stresses (heat, drought, salt) suggested their role in stress response. Majority of TaCCX and TaNCL family genes were found highly affected during various abiotic stresses. However, the role of individual gene needs to be established. The present study unfolded the opportunity for detail

  1. Characterization of Corn Starch Films Reinforced with CaCO3 Nanoparticles

    Science.gov (United States)

    Sun, Qingjie; Xi, Tingting; Li, Ying; Xiong, Liu

    2014-01-01

    The characterization of corn starch (CS) films impregnated with CaCO3 nanoparticles was investigated. Criteria such as morphology, crystallinity, water vapor permeability (WVP), opacity, and mechanical properties were the focus of the investigation. It was found that the CaCO3 contents had significant effects on the tensile properties of the nanocomposite films. The addition of CaCO3 nanoparticles to the CS films significantly increased tensile strength from 1.40 to 2.24 MPa, elongation from 79.21 to 118.98%, and Young’s modulus from 1.82 to 2.41 MPa. The incorporation of CaCO3 nanoparticles increased the opacity of films, lowered the degree of WVP and film solubility value compared to those of the CS films. The results of scanning electron microscopy (SEM) showed that with the increase of CaCO3 nanoparticles content in starch films, the roughness of the films increased, and pores or cavities were found on the surface of the films, while small cracks were observed in the structures of the fractured surfaces. X-ray diffraction showed that the addition of nanoparticles increased the peaks in the intensity of films. PMID:25188503

  2. IP3 Receptor-Dependent Cytoplasmic Ca2+ Signals Are Tightly Controlled by Cavβ3

    Directory of Open Access Journals (Sweden)

    Anouar Belkacemi

    2018-01-01

    Full Text Available Voltage-gated calcium channels (Cavs are major Ca2+ entry pathways in excitable cells. Their β subunits facilitate membrane trafficking of the channel’s ion-conducting α1 pore and modulate its gating properties. We report that one β subunit, β3, reduces Ca2+ release following stimulation of phospholipase C-coupled receptors and inositol 1,4,5-trisphosphate (IP3 formation. This effect requires the SH3-HOOK domain of Cavβ3, includes physical β3/IP3 receptor interaction, and prevails when agonist-induced IP3 formation is bypassed by photolysis of caged IP3. In agreement with β3 acting as a brake on Ca2+ release, fibroblast migration is enhanced in vitro, and in vivo, closure of skin wounds is accelerated in the absence of β3. To mediate specific physiological responses and to prevent Ca2+ toxicity, cytoplasmic Ca2+ signals must be tightly controlled. The described function of β3, unrelated to its function as a Cav subunit, adds to this tight control.

  3. Mutations in PIK3CA are infrequent in neuroblastoma

    International Nuclear Information System (INIS)

    Dam, Vincent; Morgan, Brian T; Mazanek, Pavel; Hogarty, Michael D

    2006-01-01

    Neuroblastoma is a frequently lethal pediatric cancer in which MYCN genomic amplification is highly correlated with aggressive disease. Deregulated MYC genes require co-operative lesions to foster tumourigenesis and both direct and indirect evidence support activated Ras signaling for this purpose in many cancers. Yet Ras genes and Braf, while often activated in cancer cells, are infrequent targets for activation in neuroblastoma. Recently, the Ras effector PIK3CA was shown to be activated in diverse human cancers. We therefore assessed PIK3CA for mutation in human neuroblastomas, as well as in neuroblastomas arising in transgenic mice with MYCN overexpressed in neural-crest tissues. In this murine model we additionally surveyed for Ras family and Braf mutations as these have not been previously reported. Sixty-nine human neuroblastomas (42 primary tumors and 27 cell lines) were sequenced for PIK3CA activating mutations within the C2, helical and kinase domain 'hot spots' where 80% of mutations cluster. Constitutional DNA was sequenced in cases with confirmed alterations to assess for germline or somatic acquisition. Additionally, Ras family members (Hras1, Kras2 and Nras) and the downstream effectors Pik3ca and Braf, were sequenced from twenty-five neuroblastomas arising in neuroblastoma-prone transgenic mice. We identified mutations in the PIK3CA gene in 2 of 69 human neuroblastomas (2.9%). Neither mutation (R524M and E982D) has been studied to date for effects on lipid kinase activity. Though both occurred in tumors with MYCN amplification the overall rate of PIK3CA mutations in MYCN amplified and single-copy tumors did not differ appreciably (2 of 31 versus 0 of 38, respectively). Further, no activating mutations were identified in a survey of Ras signal transduction genes (including Hras1, Kras2, Nras, Pik3ca, or Braf genes) in twenty-five neuroblastic tumors arising in the MYCN-initiated transgenic mouse model. These data suggest that activating

  4. Ablation of Ca(V2.1 voltage-gated Ca²⁺ channels in mouse forebrain generates multiple cognitive impairments.

    Directory of Open Access Journals (Sweden)

    Robert Theodor Mallmann

    Full Text Available Voltage-gated Ca(V2.1 (P/Q-type Ca²⁺ channels located at the presynaptic membrane are known to control a multitude of Ca²⁺-dependent cellular processes such as neurotransmitter release and synaptic plasticity. Our knowledge about their contributions to complex cognitive functions, however, is restricted by the limited adequacy of existing transgenic Ca(V2.1 mouse models. Global Ca(V2.1 knock-out mice lacking the α1 subunit Cacna1a gene product exhibit early postnatal lethality which makes them unsuitable to analyse the relevance of Ca(V2.1 Ca²⁺ channels for complex behaviour in adult mice. Consequently we established a forebrain specific Ca(V2.1 knock-out model by crossing mice with a floxed Cacna1a gene with mice expressing Cre-recombinase under the control of the NEX promoter. This novel mouse model enabled us to investigate the contribution of Ca(V2.1 to complex cognitive functions, particularly learning and memory. Electrophysiological analysis allowed us to test the specificity of our conditional knock-out model and revealed an impaired synaptic transmission at hippocampal glutamatergic synapses. At the behavioural level, the forebrain-specific Ca(V2.1 knock-out resulted in deficits in spatial learning and reference memory, reduced recognition memory, increased exploratory behaviour and a strong attenuation of circadian rhythmicity. In summary, we present a novel conditional Ca(V2.1 knock-out model that is most suitable for analysing the in vivo functions of Ca(V2.1 in the adult murine forebrain.

  5. Age-dependent changes in diastolic Ca2+ and Na+ concentrations in dystrophic cardiomyopathy: Role of Ca2+ entry and IP3

    International Nuclear Information System (INIS)

    Mijares, Alfredo; Altamirano, Francisco; Kolster, Juan; Adams, José A.; López, José R.

    2014-01-01

    Highlights: • Age-dependent increase in [Ca 2+ ] d and [Na + ] d in mdx cardiomyocytes. • Gadolinium significantly reduced both [Ca 2+ ] d and [Na + ] d at all ages. • IP 3 -pathway inhibition reduced cations concentrations in dystrophic cardiomyocytes. - Abstract: Duchenne muscular dystrophy (DMD) is a lethal X-inherited disease caused by dystrophin deficiency. Besides the relatively well characterized skeletal muscle degenerative processes, DMD is also associated with a dilated cardiomyopathy that leads to progressive heart failure at the end of the second decade. The aim of the present study was to characterize the diastolic Ca 2+ concentration ([Ca 2+ ] d ) and diastolic Na + concentration ([Na + ] d ) abnormalities in cardiomyocytes isolated from 3-, 6-, 9-, and 12-month old mdx mice using ion-selective microelectrodes. In addition, the contributions of gadolinium (Gd 3+ )-sensitive Ca 2+ entry and inositol triphosphate (IP 3 ) signaling pathways in abnormal [Ca 2+ ] d and [Na + ] d were investigated. Our results showed an age-dependent increase in both [Ca 2+ ] d and [Na + ] d in dystrophic cardiomyocytes compared to those isolated from age-matched wt mice. Gd 3+ treatment significantly reduced both [Ca 2+ ] d and [Na + ] d at all ages. In addition, blockade of the IP 3 -pathway with either U-73122 or xestospongin C significantly reduced ion concentrations in dystrophic cardiomyocytes. Co-treatment with U-73122 and Gd 3+ normalized both [Ca 2+ ] d and [Na + ] d at all ages in dystrophic cardiomyocytes. These data showed that loss of dystrophin in mdx cardiomyocytes produced an age-dependent intracellular Ca 2+ and Na + overload mediated at least in part by enhanced Ca 2+ entry through Gd 3+ sensitive transient receptor potential channels (TRPC), and by IP 3 receptors

  6. Spatial information is preferentially processed by the distal part of CA3: implication for memory retrieval.

    Science.gov (United States)

    Flasbeck, Vera; Atucha, Erika; Nakamura, Nozomu H; Yoshida, Motoharu; Sauvage, Magdalena M

    2018-07-16

    For the past decades, CA3 was considered as a single functional entity. However, strong differences between the proximal (close to the dentate gyrus) and the distal (close to CA2) parts of CA3 in terms of connectivity patterns, gene expression and electrophysiological properties suggest that it is not the case. We recently showed that proximal CA3 (together with distal CA1) preferentially deals with non-spatial information [1]. In contrast to proximal CA3, distal CA3 mainly receives and predominantly projects to spatially tuned areas. Here, we tested if distal CA3 preferentially processes spatial information, which would suggest a segregation of the spatial information along the proximodistal axis of CA3. We used a high-resolution imaging technique based on the detection of the expression of the immediate-early gene Arc, commonly used to map activity in the medial temporal lobe. We showed that distal CA3 is strongly recruited in a newly designed delayed nonmatching-to-location task with high memory demands in rats, while proximal CA3 is not. These results indicate a functional segregation of CA3 that mirrors the one reported in CA1, and suggest the existence of a distal CA3- proximal CA1 spatial subnetwork. These findings bring further evidence for the existence of 'specialized' spatial and non-spatial subnetworks segregated along the proximodistal axis of the hippocampus and put forward the 'segregated' view of information processing in the hippocampus as a reasonable alternative to the well-accepted 'integrated' view, according to which spatial and non-spatial information are systematically integrated in the hippocampus to form episodic memory. Copyright © 2018. Published by Elsevier B.V.

  7. Significance of CaV3.2 T-type Ca2+ channels for pressure- and flow-dependent vasomotor responses in rat and mouse mesenteric small arteries

    DEFF Research Database (Denmark)

    Jensen, Lars Jørn; Björling, K.; Hansen, Pernille B. Lærkegaard

    RNA was similar in WT vs. CaV3.2-/- mice. CONCLUSION: FMVD responses appear to rely on an endothelium-dependent hyperpolarization in rat small mesenteric arteries. CaV3.2 channels are negative feedback modulators of myogenic tone in small mesenteric artery in young mice. The age-dependent decline in CaV3...... in young CaV3.2-/- mice (8-15 weeks) vs. age-matched WT mice (Pyoung WT mice, the CaV3.2 blocker NiCl2 (30 µM) significantly enhanced myogenic tone (P... was not seen (N=4). In young and old CaV3.2-/- mice no effects of NiCl2 were observed. The FMVD response in rat mesenteric arteries was not blocked by L-NAME, but was almost abolished by the SKCa/IKCa channel blockers apamin/TRAM-34 (50 nM/1 µM) (P

  8. The diagnostic value of determination of serum GOLPH3 associated with CA125, CA19.9 in patients with ovarian cancer.

    Science.gov (United States)

    Fan, H-Y; Duan, D-M; Liu, Y-F

    2017-09-01

    To evaluate the value of three tumor markers serum Golgi phosphoprotein-3 (GOLPH3), cancer antigen 125 (CA125) and cancer antigen 19-9 (CA19.9) in the diagnosis and postoperative evaluation of ovarian cancer by detecting these three markers. A total of 187 patients were studied and included in the ovarian cancer group, benign pelvic mass group, and the normal control group. The levels of serum Golgi phosphoprotein-3 (GOLPH3), cancer antigen 125 (CA125) and cancer antigen 199 (CA19.9) were detected, respectively, and their effects on the diagnosis, evaluation, pathology typing and staging of ovarian cancer were measured. The sensitivity of the detection of ovarian cancer by GOLPH3 combined with CA125 and CA19.9 was higher than that by a single marker (pserum GOLPH3 in patients with serous and endometrioid carcinoma was significantly higher than that in patients with mucinous carcinoma, clear-cell carcinoma and germ cell tumor (pserum GOLPH3 level between patients with ovarian malignancies at stage III-IV and those at stage I-II (p>0.05). The levels of serum GOLPH3, CA125 and CA19.9 in patients with ovarian malignancies after surgery were significantly lower than those before surgery (p<0.05). The combined detection by GOLPH3, CA125, and CA19.9 may improve the diagnosis rate of ovarian epithelial cancer. GOLPH3, as a new ovarian cancer tumor marker used in clinical diagnosis, is expected to become an important indicator for the early diagnosis of ovarian cancer and the determination of clinical surgery efficacy.

  9. Excitatory Synaptic Drive and Feedforward Inhibition in the Hippocampal CA3 Circuit Are Regulated by SynCAM 1.

    Science.gov (United States)

    Park, Kellie A; Ribic, Adema; Laage Gaupp, Fabian M; Coman, Daniel; Huang, Yuegao; Dulla, Chris G; Hyder, Fahmeed; Biederer, Thomas

    2016-07-13

    Select adhesion proteins control the development of synapses and modulate their structural and functional properties. Despite these important roles, the extent to which different synapse-organizing mechanisms act across brain regions to establish connectivity and regulate network properties is incompletely understood. Further, their functional roles in different neuronal populations remain to be defined. Here, we applied diffusion tensor imaging (DTI), a modality of magnetic resonance imaging (MRI), to map connectivity changes in knock-out (KO) mice lacking the synaptogenic cell adhesion protein SynCAM 1. This identified reduced fractional anisotropy in the hippocampal CA3 area in absence of SynCAM 1. In agreement, mossy fiber refinement in CA3 was impaired in SynCAM 1 KO mice. Mossy fibers make excitatory inputs onto postsynaptic specializations of CA3 pyramidal neurons termed thorny excrescences and these structures were smaller in the absence of SynCAM 1. However, the most prevalent targets of mossy fibers are GABAergic interneurons and SynCAM 1 loss unexpectedly reduced the number of excitatory terminals onto parvalbumin (PV)-positive interneurons in CA3. SynCAM 1 KO mice additionally exhibited lower postsynaptic GluA1 expression in these PV-positive interneurons. These synaptic imbalances in SynCAM 1 KO mice resulted in CA3 disinhibition, in agreement with reduced feedforward inhibition in this network in the absence of SynCAM 1-dependent excitatory drive onto interneurons. In turn, mice lacking SynCAM 1 were impaired in memory tasks involving CA3. Our results support that SynCAM 1 modulates excitatory mossy fiber inputs onto both interneurons and principal neurons in the hippocampal CA3 area to balance network excitability. This study advances our understanding of synapse-organizing mechanisms on two levels. First, the data support that synaptogenic proteins guide connectivity and can function in distinct brain regions even if they are expressed broadly

  10. Synaptically evoked Ca2+ release from intracellular stores is not influenced by vesicular zinc in CA3 hippocampal pyramidal neurones.

    Science.gov (United States)

    Evstratova, Alesya; Tóth, Katalin

    2011-12-01

    The co-release of neuromodulatory substances in combination with classic neurotransmitters such as glutamate and GABA from individual presynaptic nerve terminals has the capacity to dramatically influence synaptic efficacy and plasticity. At hippocampal mossy fibre synapses vesicular zinc is suggested to serve as a cotransmitter capable of regulating calcium release from internal stores in postsynaptic CA3 pyramidal cells. Here we investigated this possibility using combined intracellular ratiometric calcium imaging and patch-clamp recording techniques. In acute hippocampal slices a brief train of mossy fibre stimulation produced a large, delayed postsynaptic Ca(2+) wave that was spatially restricted to the proximal apical dendrites of CA3 pyramidal cells within stratum lucidum. This calcium increase was sensitive to intracellularly applied heparin indicating reliance upon release from internal stores and was triggered by activation of both group I metabotropic glutamate and NMDA receptors. Importantly, treatment of slices with the membrane-impermeant zinc chelator CaEDTA did not influence the synaptically evoked postsynaptic Ca(2+) waves. Moreover, mossy fibre stimulus evoked postsynaptic Ca(2+) signals were not significantly different between wild-type and zinc transporter 3 (ZnT3) knock-out animals. Considered together our data do not support a role for vesicular zinc in regulating mossy fibre evoked Ca(2+) release from CA3 pyramidal cell internal stores.

  11. Compound effect of CaCO3 and CaSO4·2H2O on the strength of steel slag: cement binding materials

    International Nuclear Information System (INIS)

    Qi, Liqian; Liu, Jiaxiang; Liu, Qian

    2016-01-01

    In this study, we replaced 30% of the cement with steel slag to prepare binding material; additionally, small amounts of CaCO 3 and CaSO 4 ·2H 2 O were added. This was done to study the compound effect of CaCO 3 and CaSO 4 ·2H 2 O on the strength of steel slag-cement binding materials. The hydration degree of the steel slag cementitious material was analyzed by XRD, TG and SEM. The results showed that the optimum proportions of CaCO 3 and CaSO 4 ·2H 2 O were 3% and 2%, respectively. Compared with the steel slag-cement binders without adding CaCO 3 and CaSO 4 ·2H 2 O, the compressive strength increased by 59.9% at 3 days and by 17.8% at 28 days. Acting as the nucleation matrix, CaCO 3 could accelerate the hydration of C 3 S. In addition, CaCO 3 was involved in the hydration reaction, generating a new hydration product, which could stably exist in a slurry. Meanwhile, CaSO 4 ·2H 2 O could increase the number of AFt. The compound effect of CaCO 3 and CaSO 4 ·2H 2 O enhanced the intensity of steel slag-cement binding materials and improved the whole hydration behavior. (author)

  12. Reverse mode Na+/Ca2+ exchange mediated by STIM1 contributes to Ca2+ influx in airway smooth muscle following agonist stimulation

    Directory of Open Access Journals (Sweden)

    Fox Jane

    2010-12-01

    Full Text Available Abstract Background Agonist stimulation of airway smooth muscle (ASM results in IP3 mediated Ca2+ release from the sarcoplasmic reticulum followed by the activation of store operated and receptor operated non-selective cation channels. Activation of these non-selective channels also results in a Na+ influx. This localised increase in Na+ levels can potentially switch the Na+/Ca2+ exchanger into reverse mode and so result in a further influx of Ca2+. The aim of this study was to characterise the expression and physiological function of the Na+/Ca2+ exchanger in cultured human bronchial smooth muscle cells and determine its contribution to agonist induced Ca2+ influx into these cells. Methods The expression profile of NCX (which encodes the Na+/Ca2+ exchanger homologues in cultured human bronchial smooth muscle cells was determined by reverse transcriptase PCR. The functional activity of reverse mode NCX was investigated using a combination of whole cell patch clamp, intracellular Ca2+ measurements and porcine airway contractile analyses. KB-R7943 (an antagonist for reverse mode NCX and target specific siRNA were utilised as tools to inhibit NCX function. Results NCX1 protein was detected in cultured human bronchial smooth muscle cells (HBSMC cells and NCX1.3 was the only mRNA transcript variant detected. A combination of intracellular Na+ loading and addition of extracellular Ca2+ induced an outwardly rectifying current which was augmented following stimulation with histamine. This outwardly rectifying current was inhibited by 10 μM KB-R7943 (an antagonist of reverse mode NCX1 and was reduced in cells incubated with siRNA against NCX1. Interestingly, this outwardly rectifying current was also inhibited following knockdown of STIM1, suggesting for the first time a link between store operated cation entry and NCX1 activation. In addition, 10 μM KB-R7943 inhibited agonist induced changes in cytosolic Ca2+ and induced relaxation of porcine

  13. X-ray Photoelectron Spectroscopy study of CaV1-xMoxO3

    Science.gov (United States)

    Belyakov, S. A.; Kuznetsov, M. V.; Shkerin, S. N.

    2018-06-01

    An investigation was carried out on perovskite-based derivatives of CaV1-xMoxO3-δ using X-ray Photoelectron Spectroscopy (XPS). According to the XRD pattern, the area of homogeneity covers the region from x = 0 to x = 0.6. Wide XPS-peaks of Ca, V, Mo and O are observed, signalling that elements are presented in multiple states. A model for explaining the large chemical shifts of XPS peaks due to different charging effects on different parts of the sample surface is proposed.

  14. Local-moment formation and metal–nonmetal transition in Ca1 ...

    Indian Academy of Sciences (India)

    Abstract. Electron-doped metallic states of Ca1−x Yx VO3 and Ca1−x Yx TiO3 change into non- metallic states around x ∼ 0.4 and 0.6, respectively. The residual resistivity in the metallic states increases with increasing effective magnetic moment or coefficient of T2 term of resistivity. The effective moment reaches ∼ 0.5 ...

  15. Cadmium induces Ca2+ mediated, calpain-1/caspase-3-dependent apoptosis in primary cultured rat proximal tubular cells.

    Science.gov (United States)

    Wang, Hong; Zhai, Nianhui; Chen, Ying; Xu, Haibin; Huang, Kehe

    2017-07-01

    Calcium, as a ubiquitous second messenger, governs a large array of cellular processes and is necessary for cell survival. More recently, it was observed that the cytosolic Ca 2+ concentration ([Ca 2+ ] c ) elevation could induce apoptosis in primary cultured rat proximal tubular (rPT) cells exposed to cadmium (Cd), but the concrete mechanism is still unclear. This study was designed to investigate the signal pathway involved in [Ca 2+ ] c elevation-mediated apoptosis. The results confirmed the elevation of [Ca 2+ ] c by confocal microscopy and enhancement of the apoptosis by Hoechst 33258 staining and flow cytometer when rPT cells were exposed to Cd for 12h. Then we demonstrated that Cd enhanced the protein levels of active calpain-1 and caspase-3 in rPT cells. Pretreatment with a cytosolic Ca 2+ chelator, 1,2-Bis (2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM), markedly blocked the up-regulation of active calpain-1 and caspase-3 and inhibited the apoptosis induced by Cd. Further, rPT cells were pretreated with a cell-permeable selective calpain-1 inhibitor, 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) and caspase-3 inhibitor, N-Acetyl-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO), respectively. PD150606 significantly attenuated the up-regulation of active caspase-3 and the apoptosis induced by Cd. As expected, inhibition of active caspase-3 by Ac-DEVD-CHO decreased the apoptosis induced by Cd. Taken together, it could be concluded that [Ca 2+ ] c elevation did act as a pro-apoptotic signal in Cd-induced cytotoxicity of rPT cells, triggered calpain-1 and caspase-3 activation in turn, and induced apoptosis of rPT cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Efeitos de relações CaSO4/CaCO3 na mobilidade de nutrientes no solo e no crescimento do algodoeiro

    Directory of Open Access Journals (Sweden)

    A. A. Silva

    1998-09-01

    Full Text Available O experimento, realizado em casa de vegetação no Departamento de Ciência do Solo da Universidade Federal de Lavras, teve por objetivo estudar o efeito de diferentes relações de CaSO4/CaCO3, que simulam o uso de gesso e calcário, na movimentação de nutrientes no solo e no crescimento do algodoeiro, cultivar IAC-20. As proporções de CaSO4/CaCO3 utilizadas foram: 0/100, 25/75, 50/50, 75/25 e 100/0, com base em peso equivalente, além de um tratamento-testemunha, sem aplicação de CaSO4 e CaCO3. Observou-se acentuada movimentação de cálcio e de sulfato em profundidade, como íons acompanhantes, com o aumento da relação CaSO4/CaCO3. Para o N-NO3- e Mg2+, ao contrário do N-NH4+ e K+, observou-se um acúmulo em profundidade, com a elevação da relação CaSO4/CaCO3. Neste estudo, o gesso teve pouco ou nenhum efeito sobre a acidez e Al trocável presentes nas camadas subsuperficiais. A produção de matéria seca do algodoeiro foi reduzida com o aumento da relação CaSO4/CaCO3, porém, quando comparada à do tratamento-testemunha, a aplicação de gesso aumentou-a significativamente, atestando o potencial de uso do gesso agrícola.

  17. Activity of RE/sub 2/O/sub 3/ in liquid La/sub 2/O/sub 3/-Al/sub 2/O/sub 3/-CaF/sub 2/ and Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slags

    International Nuclear Information System (INIS)

    Changzhen, W.; Shuqing, Y.; Qieng, D.

    1985-01-01

    In the course of electro-slag refining, if the slag contains rare earth oxides, the amount of rare earth introduced to the steel depends on the composition of the slag and other conditions. The main aim of this investigation is to study the activity of RE/sub 2/O/sub 3/ in the electro-slags of various compositions. One is the La/sub 2/O/sub 3/-CaO-CaF/sub 2/ ternary slag system and the other is the Ce/sub 2/O/sub 3/-CaO-CaF/sub 2/ slag system. The iso-activity diagram for RE/sub 2/O/sub 3/ and the liquid boundary for slags system were estimated

  18. Effect of carbonation temperature on CO_2 adsorption capacity of CaO derived from micro/nanostructured aragonite CaCO_3

    International Nuclear Information System (INIS)

    Hlaing, Nwe Ni; Sreekantan, Srimala; Hinode, Hirofumi; Kurniawan, Winarto; Thant, Aye Aye; Othman, Radzali; Mohamed, Abdul Rahman; Salime, Chris

    2016-01-01

    Recent years, CaO-based synthetic materials have been attracted attention as potential adsorbents for CO_2 capture mainly due to their high CO_2 adsorption capacity. In this study, micro/nanostructured aragonite CaCO_3 was synthesized by a simple hydrothermal method with using polyacrylamide (PAM). The structural, morphological and thermal properties of the synthesized sample were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and thermogravimetry analysis (TG-DTA). The XRD and FESEM results showed that the obtained sample was aragonite CaCO_3 with aggregated nanorods and microspheres composed of nanorods. A TG-DTA apparatus with Thermoplus 2 software was used to investigate the effect of carbonation temperature on the CO_2 adsorption capacity of CaO derived from aragonite CaCO_3 sample. At 300 °C, the sample reached the CO_2 adsorption capacity of 0.098 g-CO_2/g-adsorbent, whereas the sample achieved the highest capacity of 0.682 g-CO_2/g-adsorbent at 700 °C. The results showed that the carbonation temperature significantly influenced on the CO_2 adsorption capacity of the CaO derived from aragonite CaCO_3.

  19. BAG3 regulates contractility and Ca(2+) homeostasis in adult mouse ventricular myocytes.

    Science.gov (United States)

    Feldman, Arthur M; Gordon, Jennifer; Wang, JuFang; Song, Jianliang; Zhang, Xue-Qian; Myers, Valerie D; Tilley, Douglas G; Gao, Erhe; Hoffman, Nicholas E; Tomar, Dhanendra; Madesh, Muniswamy; Rabinowitz, Joseph; Koch, Walter J; Su, Feifei; Khalili, Kamel; Cheung, Joseph Y

    2016-03-01

    Bcl2-associated athanogene 3 (BAG3) is a 575 amino acid anti-apoptotic protein that is constitutively expressed in the heart. BAG3 mutations, including mutations leading to loss of protein, are associated with familial cardiomyopathy. Furthermore, BAG3 levels have been found to be reduced in end-stage non-familial failing myocardium. In contrast to neonatal myocytes in which BAG3 is found in the cytoplasm and involved in protein quality control and apoptosis, in adult mouse left ventricular (LV) myocytes BAG3 co-localized with Na(+)-K(+)-ATPase and L-type Ca(2+) channels in the sarcolemma and t-tubules. BAG3 co-immunoprecipitated with β1-adrenergic receptor, L-type Ca(2+) channels and phospholemman. To simulate decreased BAG3 protein levels observed in human heart failure, we targeted BAG3 by shRNA (shBAG3) in adult LV myocytes. Reducing BAG3 by 55% resulted in reduced contraction and [Ca(2+)]i transient amplitudes in LV myocytes stimulated with isoproterenol. L-type Ca(2+) current (ICa) and sarcoplasmic reticulum (SR) Ca(2+) content but not Na(+)/Ca(2+) exchange current (INaCa) or SR Ca(2+) uptake were reduced in isoproterenol-treated shBAG3 myocytes. Forskolin or dibutyryl cAMP restored ICa amplitude in shBAG3 myocytes to that observed in WT myocytes, consistent with BAG3 having effects upstream and at the level of the receptor. Resting membrane potential and action potential amplitude were unaffected but APD50 and APD90 were prolonged in shBAG3 myocytes. Protein levels of Ca(2+) entry molecules and other important excitation-contraction proteins were unchanged in myocytes with lower BAG3. Our findings that BAG3 is localized at the sarcolemma and t-tubules while modulating myocyte contraction and action potential duration through specific interaction with the β1-adrenergic receptor and L-type Ca(2+) channel provide novel insight into the role of BAG3 in cardiomyopathies and increased arrhythmia risks in heart failure. Copyright © 2016 Elsevier Ltd. All rights

  20. BAG3 regulates contractility and Ca2+ homeostasis in adult mouse ventricular myocytes

    Science.gov (United States)

    Feldman, Arthur M.; Gordon, Jennifer; Wang, JuFang; Song, Jianliang; Zhang, Xue-Qian; Myers, Valerie D.; Tilley, Douglas G.; Gao, Erhe; Hoffman, Nicholas E.; Tomar, Dhanendra; Madesh, Muniswamy; Rabinowitz, Joseph; Koch, Walter J.; Su, Feifei; Khalili, Kamel; Cheung, Joseph Y.

    2016-01-01

    Bcl2-associated athanogene 3 (BAG3) is a 575 amino acid anti-apoptotic protein that is constitutively expressed in the heart. BAG3 mutations, including mutations leading to loss of protein, are associated with familial cardiomyopathy. Furthermore, BAG3 levels have been found to be reduced in end-stage non-familial failing myocardium. In contrast to neonatal myocytes in which BAG3 is found in the cytoplasm and involved in protein quality control and apoptosis, in adult mouse left ventricular (LV) myocytes BAG3 co-localized with Na+-K+-ATPase and L-type Ca2+ channels in the sarcolemma and t-tubules. BAG3 co-immunoprecipitated with β1-adrenergic receptor, L-type Ca2+ channels and phospholemman. To simulate decreased BAG3 protein levels observed in human heart failure, we targeted BAG3 by shRNA (shBAG3) in adult LV myocytes. Reducing BAG3 by 55% resulted in reduced contraction and [Ca2+]i transient amplitudes in LV myocytes stimulated with isoproterenol. L-type Ca2+ current (ICa) and sarcoplasmic reticulum (SR) Ca2+ content but not Na+/Ca2+ exchange current (INaCa) or SR Ca2+ uptake were reduced in isoproterenol-treated shBAG3 myocytes. Forskolin or dibutyrl cAMP restored ICa amplitude in shBAG3 myocytes to that observed in WT myocytes, consistent with BAG3 having effects upstream and at the level of the receptor. Resting membrane potential and action potential amplitude were unaffected but APD50 and APD90 were prolonged in shBAG3 myocytes. Protein levels of Ca2+ entry molecules and other important excitation-contraction proteins were unchanged in myocytes with lower BAG3. Our findings that BAG3 is localized at the sarcolemma and t-tubules while modulating myocyte contraction and action potential duration through specific interaction with the β1-adrenergic receptor and L-type Ca2+ channel provide novel insight into the role of BAG3 in cardiomyopathies and increased arrhythmia risks in heart failure. PMID:26796036

  1. Aspirin exerts high anti-cancer activity in PIK3CA-mutant colon cancer cells.

    Science.gov (United States)

    Gu, Mancang; Nishihara, Reiko; Chen, Yang; Li, Wanwan; Shi, Yan; Masugi, Yohei; Hamada, Tsuyoshi; Kosumi, Keisuke; Liu, Li; da Silva, Annacarolina; Nowak, Jonathan A; Twombly, Tyler; Du, Chunxia; Koh, Hideo; Li, Wenbin; Meyerhardt, Jeffrey A; Wolpin, Brian M; Giannakis, Marios; Aguirre, Andrew J; Bass, Adam J; Drew, David A; Chan, Andrew T; Fuchs, Charles S; Qian, Zhi Rong; Ogino, Shuji

    2017-10-20

    Evidence suggests that nonsteroidal anti-inflammatory drug aspirin (acetylsalicylic acid) may improve patient survival in PIK3CA -mutant colorectal carcinoma, but not in PIK3CA -wild-type carcinoma. However, whether aspirin directly influences the viability of PIK3CA -mutant colon cancer cells is poorly understood. We conducted in vitro experiments to test our hypothesis that the anti-proliferative activity of aspirin might be stronger for PIK3CA -mutant colon cancer cells than for PIK3CA -wild-type colon cancer cells. We measured the anti-proliferative effect of aspirin at physiologic concentrations in seven PIK3CA -mutant and six PIK3CA -wild-type human colon cancer cell lines. After exposure to aspirin, the apoptotic index and cell cycle phase of colon cancer cells were assessed. In addition, the effect of aspirin was examined in parental SW48 cells and SW48 cell clones with individual knock-in PIK3CA mutations of either c.3140A>G (p.H1047R) or c.1633G>A (p.E545K). Aspirin induced greater dose-dependent loss of cell viability in PIK3CA -mutant cells than in PIK3CA -wild-type cells after treatment for 48 and 72 hours. Aspirin treatment also led to higher proportions of apoptotic cells and G0/G1 phase arrest in PIK3CA -mutant cells than in PIK3CA -wild-type cells. Aspirin treatment of isogenic SW48 cells carrying a PIK3CA mutation, either c.3140A>G (p.H1047R) or c.1633G>A (p. E545K), resulted in a more significant loss of cell viability compared to wild-type controls. Our findings indicate that aspirin causes cell cycle arrest, induces apoptosis, and leads to loss of cell viability more profoundly in PIK3CA -mutated colon cancer cells than in PIK3CA -wild-type colon cancer cells. These findings support the use of aspirin to treat patients with PIK3CA -mutant colon cancer.

  2. Structure and magnetic properties of La2/3Sr1/3MnO3/CaMnO3 multilayers

    International Nuclear Information System (INIS)

    Granada, Mara; Sirena, Martin; Steren, Laura B.; Leyva, Gabriela

    2004-01-01

    Structural and magnetic properties of manganite-based multilayers, La 2/3 Sr 1/3 MnO 3 /CaMnO 3 , composed of ferromagnetic metals and antiferromagnetic insulator barriers are investigated in this work. Compounds of similar lattice parameters were used to build the samples, so we expect an excellent stacking of the different layers along the structure. To get a first insight of this system, the crystalline structure of a series of samples, grown on (1 0 0) SrTiO 3 and (1 0 0) MgO single-crystalline substrates, has been studied. X-ray diffraction patterns show that the structure is strongly textured in the (1 0 0) direction when grown on SrTiO 3 , regardless the composition of the bottom layer. A different result is found on the same system grown on MgO: when the buffer layer is CaMnO 3 , the structure grows in the (1 1 0) orientation while it grows in the (1 0 0) direction when the bottom layer is La 2/3 Sr 1/3 MnO 3 . Magnetic coupling of the ferromagnetic layers across the antiferromagnetic spacer has been studied with magnetization measurements

  3. Electron radiation damages to dicalcium (Ca{sub 2}SiO{sub 4}) and tricalcium (Ca{sub 3}SiO{sub 5}) orthosilicates

    Energy Technology Data Exchange (ETDEWEB)

    Noirfontaine, Marie-Noëlle de; Dunstetter, Frédéric [Laboratoire des Solides Irradiés, UMR CNRS 7642, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau Cedex (France); Courtial, Mireille [Laboratoire des Solides Irradiés, UMR CNRS 7642, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau Cedex (France); Université d’Artois, 1230 Rue de l’Université, CS 20819, F-62408 Béthune (France); Signes-Frehel, Marcel [Laboratoire des Solides Irradiés, UMR CNRS 7642, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau Cedex (France); Wang, Guillaume [Laboratoire Matériaux et Phénomènes Quantiques, UMR CNRS 7162, Université Paris Diderot, F-75205 Paris Cedex 13 (France); Gorse - Pomonti, Dominique [Laboratoire des Solides Irradiés, UMR CNRS 7642, Ecole Polytechnique, Université Paris-Saclay, F-91128 Palaiseau Cedex (France)

    2016-05-01

    Electron radiation damages to dicalcium silicate (Ca{sub 2}SiO{sub 4}) and tricalcium silicate (Ca{sub 3}SiO{sub 5}) are reported for the first time in this paper. With increasing flux, between 2.7 × 10{sup 17} and 2.2 × 10{sup 22} e{sup −} cm{sup −2} s{sup −1}, decomposition into nanodomains of crystalline CaO plus an amorphous silica rich phase is first observed for both silicates, then amorphization at higher flux always for both silicates, and finally hole drilling but only for Ca{sub 3}SiO{sub 5}. These structural modifications are accompanied by a net reduction of Ca content under the electron beam depending on the silicate species. These radiation effects occur for values of flux and dose larger than in previously studied orthosilicates (like olivines), and much larger than in all tectosilicates.

  4. Ozone (O{sub 3}) elicits neurotoxicity in spinal cord neurons (SCNs) by inducing ER Ca{sup 2+} release and activating the CaMKII/MAPK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yun; Lin, Xiaowen; Zhao, XueJun; Xie, Juntian; JunNan, Wang; Sun, Tao; Fu, Zhijian, E-mail: zhijian_fu@163.com

    2014-11-01

    Ozone (O{sub 3}) is widely used in the treatment of spinal cord related diseases. Excess or accumulation of this photochemical air can however be neurotoxic. In this study, in vitro cultured Wister rat spinal cord neurons (SCNs) were used to investigate the detrimental effects and underlying mechanisms of O{sub 3}. Ozone in a dose-dependent manner inhibited cell viability at a range of 20 to 500 μg/ml, with the dose at 40 μg/ml resulting in a decrease of cell viability to 75%. The cell death after O{sub 3} exposure was related to endoplasmic reticulum (ER) calcium (Ca{sup 2+}) release. Intracellular Ca{sup 2+} chelator, ER stabilizer (inositol 1,4,5-trisphosphate receptor (IP3R) antagonist and ryanodine receptor (RyR) antagonist) and calcium/calmodulin-dependent protein kinase II (CaMKII) antagonist could effectively block Ca{sup 2+} mobilization and inhibit cell death following 40 μg/ml O{sub 3} exposure. In addition, ER Ca{sup 2+} release due to O{sub 3} exposure enhanced phospho-p38 and phospho-JNK levels and apoptosis of SCNs through activating CaMKII. Based on these results, we confirm that ozone elicits neurotoxicity in SCNs via inducing ER Ca{sup 2+} release and activating CaMKII/MAPK signaling pathway. Therefore, physicians should get attention to the selection of treatment concentrations of oxygen/ozone. And, approaches, such as chelating intracellular Ca{sup 2+} and stabilizing neuronal Ca{sup 2+} homeostasis could effectively ameliorate the neurotoxicity of O{sub 3}. - Highlights: • Exposure to O{sub 3} can reduce the viability of SCNs and cause the cell death. • Exposure to O{sub 3} can trigger RyR and IP3R dependent intracellular Ca{sup 2+} release. • Exposure to O{sub 3} can enhance the phospho-CaMKII, phospho-JNK and phospho-p38 levels.

  5. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

    Science.gov (United States)

    Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

    2016-01-01

    Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

  6. Phase diagram study for the PbO-ZnO-CaO-SiO_2 -“Fe_2O_3 ” system in air with CaO/SiO_2 in 1.1 and PbO/(CaO+SiO_2) in 2.4 weight ratios

    International Nuclear Information System (INIS)

    Lopez-Rodriguez, Josue; Romero-Serrano, Antonio; Hernandez-Ramirez, Aurelio; Cruz-Ramirez, Alejandro; Almaguer-Guzman, Isaias; Benavides-Perez, Ricardo; Flores-Favela, Manuel

    2017-01-01

    An experimental study on the phase equilibrium and the liquidus isotherms for the PbO-ZnO-CaO-SiO_2 -“Fe_2O_3 ” system with CaO/SiO_2 in 1.1 and PbO/(CaO+SiO_2) in 2.4 weight ratios, respectively, was carried out in the temperature range 1100-1300 deg C (1373-1573 K). High temperature phases were determined by the equilibrium-quenching method. Results are presented in the form of pseudo-ternary sections “Fe_2O_3 ”-ZnO-(PbO+CaO+SiO_2). X-Ray diffraction (XRD) and SEM-EDS results showed that the phase equilibria in this system are dominated by the high melting temperature spinel and zincite phases. It was observed that if the system is at a temperature below 1300 deg C and the total (Fe_2O_3 + ZnO) is greater than 20 wt%, spinel and/or zincite will be present in the slag system. As an application of the phase diagram, the liquid phase compositions below the liquidus surface were estimated, then their viscosities were calculated using FACTSage software. (author)

  7. Compound Method to Disperse CaCO3 Nanoparticles to Nano-Size in Water.

    Science.gov (United States)

    Gu, Sui; Cai, Jihua; Wang, Jijun; Yuan, Ye; Chang, Dewu; Chikhotkin, Viktor F

    2015-12-01

    The invalidation of CaCO3 nanoparticles (nCaCO3) is often caused by the fact of agglomeration and inhomogeneous dispersion which limits its application into water-based drilling muds for low permeability reservoirs such as coalbed methane reservoir and shale gas/oil reservoir. Effective methods to disperse nCaCO3 to nano-size (≤ 100 nm) in water have seldom been reported. Here we developed a compound method containing mechanical stirring, ultrasonic treatment, the use of surfactant and stabilizer to disperse nCaCO3 in water. It comprises the steps adding 2% nCaCO3, 1% sodium dodecyl sulfonate (SDS), 2% cetyltrimethyl ammonium bromide (CTAB), 2% OP-10, 3% to 4% biopolymer (XC) in water successively, stirring it at a shear rate of 6000 to 8000 r/min for 15 minutes and treating it with ultrasonic at a frequency of 28 KHz for 30 to 40 minutes. The dispersed nCaCO3 was characterized with scanning electron microscope (SEM), transmission electron microscope (TEM) and particle size distribution (PSD) tests. We found that nCaCO3 could be dispersed to below 100 nm in water and the medium value of nCaCO3 was below 50 nm. This method paved the way for the utilization of nCaCO3 in drilling fluid and completion fluid for low permeability reservoirs such as coal seams and shale gas/oil formations.

  8. Breast cancer 1 (BrCa1 may be behind decreased lipogenesis in adipose tissue from obese subjects.

    Directory of Open Access Journals (Sweden)

    Francisco J Ortega

    Full Text Available CONTEXT: Expression and activity of the main lipogenic enzymes is paradoxically decreased in obesity, but the mechanisms behind these findings are poorly known. Breast Cancer 1 (BrCa1 interacts with acetyl-CoA carboxylase (ACC reducing the rate of fatty acid biosynthesis. In this study, we aimed to evaluate BrCa1 in human adipose tissue according to obesity and insulin resistance, and in vitro cultured adipocytes. RESEARCH DESIGN AND METHODS: BrCa1 gene expression, total and phosphorylated (P- BrCa1, and ACC were analyzed in adipose tissue samples obtained from a total sample of 133 subjects. BrCa1 expression was also evaluated during in vitro differentiation of human adipocytes and 3T3-L1 cells. RESULTS: BrCa1 gene expression was significantly up-regulated in both omental (OM; 1.36-fold, p = 0.002 and subcutaneous (SC; 1.49-fold, p = 0.001 adipose tissue from obese subjects. In parallel with increased BrCa1 mRNA, P-ACC was also up-regulated in SC (p = 0.007 as well as in OM (p = 0.010 fat from obese subjects. Consistent with its role limiting fatty acid biosynthesis, both BrCa1 mRNA (3.5-fold, p<0.0001 and protein (1.2-fold, p = 0.001 were increased in pre-adipocytes, and decreased during in vitro adipogenesis, while P-ACC decreased during differentiation of human adipocytes (p = 0.005 allowing lipid biosynthesis. Interestingly, BrCa1 gene expression in mature adipocytes was restored by inflammatory stimuli (macrophage conditioned medium, whereas lipogenic genes significantly decreased. CONCLUSIONS: The specular findings of BrCa1 and lipogenic enzymes in adipose tissue and adipocytes reported here suggest that BrCa1 might help to control fatty acid biosynthesis in adipocytes and adipose tissue from obese subjects.

  9. Changes in CaCO3 Burial Trump the Biological Pump

    Science.gov (United States)

    Toggweiler, J.; Dunne, J. P.

    2008-12-01

    The dramatic increases in atmospheric CO2 at the ends of ice ages are usually attributed to a one-two punch coming from the ocean. First, a weakened biological pump vents organically cycled CO2 from the deep ocean via changes in the ventilation of the deep ocean around Antarctica. The initial CO2 increase is then augmented by an enhancement of CaCO3 burial due to a process called CaCO3 compensation (after Broecker, W. S and T.-H. Peng, Global Biogeochem. Cycles, 1, 15-29, 1987). Here, we argue that the importance of the biological pump has been exaggerated. The main effect comes from circulation-induced changes in the burial of CaCO3. As shown in a recent paper by Andreas Schmittner and co-authors (Schmittner, A., E. Brook and J. Ahn, Impact of the ocean's overturning circulation on atmospheric CO2, in Ocean Circulation: Mechanisms and Impacts, Geophys. Monogr. 173, A. Schmittner, J. Chiang, and S. Hemming, eds., pp. 209-246, AGU, 2007) changes in the ventilation of the deep ocean around Antarctica gave rise to 20-30 ppm increases in atmospheric CO2 every 5,000-7,000 years during isotope stages 3 and 4 (30,000 to 70,000 years ago). None of these venting events gave rise to a compensation response. Meanwhile, Jaccard et al. (Science, 308, 1003-1006, 2005) show that all the big CO2 increases during terminations through stage 11 were accompanied by huge increases in CaCO3 burial. This suggests that the enhanced burial of CaCO3 is obligatory rather than compensatory with respect to the dramatic CO2 increases. Broecker and Peng's compensation idea is based on an assumption that the rain of CaCO3 to the sea floor is the same everywhere. More specifically, it assumes that there is no spatial correlation between the production of CaCO3 at the surface and the burial on the sea floor. We find instead that the production and burial of CaCO3 tend to be co-located in regional "hot spots" and that burial in the hot spots balances the input of Ca++ and HCO3- ions in rivers. The

  10. CA 15-3: uses and limitation as a biomarker for breast cancer.

    LENUS (Irish Health Repository)

    Duffy, Michael J

    2012-02-01

    CA 15-3 which detects soluble forms of MUC-1 protein is the most widely used serum marker in patients with breast cancer. Its main use is for monitoring therapy in patients with metastatic disease. In monitoring therapy in this setting, CA 15-3 should not be used alone but measured in conjunction with diagnostic imaging, clinical history and physical examination. CA 15-3 is particularly valuable for treatment monitoring in patients that have disease that cannot be evaluated using existing radiological procedures. CA 15-3 may also be used in the postoperative surveillance of asymptomatic women who have undergone surgery for invasive breast cancer. In this setting, serial determination can provide median lead-times of 5-6 months in the early detection of recurrent\\/metastatic breast cancer. It is unclear however, whether administering systemic therapy based on this lead-time improves patient outcome. Consequently, expert panels disagree on the utility of regularly measuring CA 15-3 in the postoperative surveillance of asymptomatic women following a diagnosis of breast cancer. The main limitation of CA 15-3 as a marker for breast cancer is that serum levels are rarely increased in patients with early or localized disease.

  11. Bone scan and serum CA 15-3 in bone metastasis in breast cancer

    International Nuclear Information System (INIS)

    Mendoza, G.; Cano, R.; Morales, R.; Guzman, C.

    1996-01-01

    CA 15-3 is a tumor marker useful in evolution control of breast cancer, being the serum levels trend the most important parameter. The purpose of this study was to report our experience and show the concordance of bone scan and CA 15-3 in patients with breast cancer attending the Breast and Bone Department of INEN from June to December 1993. One hundred patients had serum CA 15-3 quantification between June and December of 1993 in Nuclear Medicine Center (Peruvian Institute of Nuclear Energy and National Institute of Neoplasic Diseases). We selected 52 patients which simultaneously had a bone scan performed. Patients age ranged from 21 to 67 years (media of 44,57 years). 99m Tc methylenediphosphonate produced by IPEN was the radiopharmaceutical employed. A GE AZS-400 gamma camera was utilized to obtain the bone scans. Ca 15-5 quantification was performed with ELSA-CA 15-3 (CIS bio France) IRMA kit. Bone scan and CA 15-3 media of 17,06 U/ml (DS 15,4). Eight patients had a positive bone scan with a CA 15-3 media of 41,6 U/ml (SD 23,0). CA 15-3 levels ranged between 4,6 and 96,0 U/ml in the first group and 10,1 U/ml to 75,0 U/ml in the second group. Using a cut-off point of 30 U/ml the sensitivity of CA 15-3 was 62,5% and the specificity 93,2% respectively. Mean CA 15-3 values of the negative and positive bone scan groups were significantly different (p=0,0361). The high negative predictive value of CA 15-3 may help to establish which patients will benefit from bone scan procedure. (authors) 42 refs., 2 tabs

  12. Interface exchange parameters in La{sub 2/3}Ca{sub 1/3}Mn{sub 3}O/La{sub 1/3}Ca{sub 2/3}Mn{sub 3}O bilayers: a Monte Carlo approach

    Energy Technology Data Exchange (ETDEWEB)

    Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Universidad Nacional de Colombia-Sede Manizales, PCM Computational Applications, Manizales (Colombia); Londoño-Navarro, J. [Universidad Nacional de Colombia-Sede Manizales, PCM Computational Applications, Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulación. Instituto de Física. Universidad de Antioquia. A.A. 1226, Medellín (Colombia)

    2013-10-15

    Ferromagnetic/antiferromagnetic (FM/AF) bilayers have been widely studied because they exhibit special phenomena, such as exchange bias and magnetoresistance. These effects are strongly influenced by interface behavior. In this work, a study of hysteresis loops in La{sub 2/3}Ca{sub 1/3}MnO{sub 3}/La{sub 1/3}Ca{sub 2/3}MnO{sub 3} bilayers is presented. Simulations were carried out using the Monte Carlo method combined with the Metropolis algorithm and Heisenberg model. The study was focused on determining the most suitable exchange parameters at the interface by applying the model proposed by Kiwi. This model considers the use of two interface exchange parameters to represent the anisotropy that occurs at the interface because of the contact between two phases (ferromagnetic and antiferromagnetic). These two interface exchange parameters were named J{sub I1} and J{sub I2}. Initially, we assumed J{sub I1} to be equal to J{sub I2} without presenting exchange bias. Then, J{sub I1} and J{sub I2} were assumed to be different. In this configuration, the exchange phenomenon appeared in the hysteresis loops. It was also observed that the exchange bias is strongly dependent on the ratio of J{sub I1} to J{sub I2}. As J{sub I1} increases, the exchange bias decreases slowly and becomes comparable to the effective exchange bias field, assuming that it only depends on ΔJ{sub I}=J{sub I1}−J{sub I2}. - Highlights: • Exchange bias is influenced by the type of interaction ions and exchange parameters. • An interface asymmetric is required for observing the exchange bias phenomenon. • Monte Carlo method allows simulating the exchange bias phenomenon in FM/AF systems.

  13. Formation of carrageenan-CaCO{sub 3} bioactive membranes

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, Lucas F.B.; Maniglia, Bianca C.; Pereira, Lourivaldo S.; Tapia-Blácido, Delia R.; Ramos, Ana P., E-mail: anapr@ffclrp.usp.br

    2016-01-01

    The high biocompatibility and resorbability of polymeric membranes have encouraged their use to manufacture medical devices. Here, we report on the preparation of membranes consisting of carrageenan, a naturally occurring sulfated polysaccharide that forms helical structures in the presence of calcium ions. We incorporated CaCO{sub 3} particles into the membranes to enhance their bioactivity and mechanical properties. Infrared spectroscopy and X-ray diffraction data confirmed CaCO{sub 3} incorporation into the polymeric matrix. We tested the bioactivity of the samples by immersing them in a solution that mimics the ionic composition and pH of the human body fluid. The hybrid membranes generated hydroxyapatite, as attested by X-ray diffraction data. Scanning electron and atomic force microscopies aided investigation of membrane topography before and after CaCO{sub 3} deposition. The wettability and surface free energy, evaluated by contact angle measures, increased in the presence of CaCO{sub 3} particles. These parameters are important for membrane implantation in the body. Moreover, membrane stiffness was up to 110% higher in the presence of the inorganic particles, as revealed by Young's modulus. - Highlights: • Hybrid kappa and iota carrageenan-CaCO{sub 3} membranes were formed. • The hybrid membrane's origin hydroxyapatite after exposure to simulated body fluid • The carrageenan's specificity to bind Ca{sup 2+} ions tailors the surface properties.

  14. Pion-nucleus forward scattering amplitudes at Δ(3,3) energies for π+---12C, 40Ca and 48Ca

    International Nuclear Information System (INIS)

    Dragoset, W.H. Jr.

    1978-01-01

    Using the LAMPF P 3 channel, small angle elastic cross sections and total cross sections were measured for π +- -- 12 C, 40 Ca and 48 Ca at incident pion kinetic energies spanning the energy region of the Δ(3,3) resonance. The sigma/sub EL/ experiment employed a spectrometer consisting of two magnets and six MWPC to measure scattering angles and momenta. For the sigma/sub T/ experiment six MWPC were positioned about the target in the beam to measure the deflection or absorption of the incident pions. Both experiments monitored the Jacobian cusp of the π → μ + ν decay to achieve absolute normalization. The two complementary data sets allowed the nuclear forward scattering amplitudes, f/sub N/(0), to be completely determined. The sigma/sub EL/ data were fit by a phenomenological small angle scattering model developed by Bethe and modified by West and Yennie. Due to the presence of nuclear-Coulomb interference in the elastic cross sections, both the magnitude and sign of Re f/sub N/ were determined by the fits. The Re f/sub N/ results were used in the sigma/sub T/ analysis to calculate corrections for the nuclear and nuclear-Coulomb interference amplitudes. Im f/sub N/ was calculated from the sigma/sub T/ results via the optical theorem. The overall self-consistencies of the data were checked by inserting IM f/sub N/ as a fixed parameter into the sigma/sub EL/ fits and comparing the resulting Re f/sub N/ to the original Re f/sub N/. It was determined that Re f/sub N/(0) has a zero near 180 MeV for both 12 C and 40 Ca. For 48 Ca, however, the Re f/sub N/ obtained by fitting with the West-Yennie formula was quite charge dependent and did not exhibit a zero in the energy range investigated. The differences in the 40 Ca, 48 Ca total cross sections were compared to a simple Kisslinger optical model calculation. The model indicated that the RMS neutron radius of 48 Ca exceeds the proton radius by 0.10 +- 0.06 fm

  15. Influence of Fe doped on the magnetocaloric behavior of La_{{2}/{3}} Ca_{{1}/{3}} Mn1-x Fe x O3 compounds: a Monte Carlo simulation

    Science.gov (United States)

    Alzate-Cardona, J. D.; Barco-Rios, H.; Restrepo-Parra, E.

    2018-02-01

    The magnetocaloric behavior of La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3 for x  =  0.00, 0.02, 0.03, 0.05, 0.07, 0.08 and 0.10 under the influence of an external magnetic field was simulated and analyzed. Simulations were carried out using the Monte Carlo method and the classical Heisenberg model under the Metropolis algorithm. These mixed valence manganites are characterized by having three types of magnetic ions corresponding to Mn4+≤ft(S=\\frac{3}{2}\\right) , which are bonded with Ca2+ , and Mneg3+ and Mneg\\prime3+ (S=2) , related to La3+ . The Fe ions were randomly included, replacing Mn ions. With this model, the magnetic entropy change, Δ S , in an isothermal process was determined. -Δ Sm showed maximum peaks around the paramagnetic-ferromagnetic transition temperature, which depends on Fe doping. Relative cooling power was computed for different Fe concentrations varying the magnetic applied field. Our model and results show that the Fe doping decreases the magnetocaloric effect in the La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3, making this a bad candidate for magnetic refrigeration. The strong dependence of the magnetocaloric behavior on Fe doping and the external magnetic field in La{2/{3}} Ca{1/{3}} Mn1-x Fe x O3 can boost these materials for the future technological applications.

  16. Electronic Structure and Thermoelectric Properties of Ca3 Co4O9

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The relation among electronic structure, chemical bond and thermoelectric property of Ca3 Co4 O9 was studied using density function and discrete variation method (DFT-DVM).The gap between the highest valence band (HVB) and the lowest conduction band (LCB) shows a semiconducting property.Ca3 Co4 O9 colsists of CoO2 and Ca2 CoO3 two layers.The HVB and LCB near Fermi level are only mainly from O(2) 2p and Co(2) 3d in Ca2 CoO3 layer. Therefore, the semiconducting or thermoelectric property of Ca3 Co4 O9 should be mainly from Ca2 CoO3 layer, but it seems to have no direct relation to the CoO2 layer,which is consistent with that binary oxides hardly have a thermoelectric property, but trinary oxide compounds have quite a good thermoelectric property.The covalent and ionic bonds of Ca2 CoO3 layer are both weaker than those of CoO2 layer.Ca plays the role of connections between CoO2 and Ca2 CoO3 layers in Ca3 Co4 O9, decrease the ionic and covalent bond strength, and improve the thermoelectric property.

  17. Induction of metallothionein(s) in organ-cultured duodenum: relationship to 1α,25-(OH)2-D3-induced CaBP synthesis

    International Nuclear Information System (INIS)

    Corradino, R.A.; Fullmer, C.S.; Frelier, E.; Maxwell, S.

    1979-01-01

    The embryonic chick duodenum contains no vitamin D-induced, calcium-binding protein (CaBP). However, when maintained in organ culture, the duodenum responds to 1α,25-(OH) 2 -D 3 in the culture medium by de novo synthesis of CaBP. Studies with this system have provided evidence that CaBP is directly involved in calcium transport at least at the mucosal surface. The present paper extends previous observations on the effects of the extremely toxic environmental pollutant, cadmium. Cadmium was found to inhibit 1α,25-(OH) 2 -D 3 -mediated responses in the organ-cultured duodenum, i.e., CaBP biosynthesis and 45 Ca uptake at the mucosal surface. Cadmium also stimulated concomitent production of a specific metallothionein (MT). Zinc had similar actions in inhibiting CaBP and stimulating Mt biosynthesis

  18. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material.

    Science.gov (United States)

    Gu, X N; Li, X L; Zhou, W R; Cheng, Y; Zheng, Y F

    2010-06-01

    Rapidly solidified (RS) Mg–3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s(-1), 30 m s(-1) and 45 m s(-1) with the as-cast Mg–3Ca alloy ingot as a raw material. The RS45 Mg–3Ca alloy ribbon showed a much more fine grain size feature (approximately 200–500 nm) in comparison to the coarse grain size (50–100 μm)of the original as-cast Mg–3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg–3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds(1.43 mm yr(-1) for RS15, 0.94 mm yr(-1) for RS30 and 0.36 mm yr(-1) for RS45). The RS Mg–3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg–3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg–3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells,whereas the as-cast Mg–3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg–3Ca alloy ribbons than that of the as-cast Mg–3Ca alloy ingot.

  19. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material

    International Nuclear Information System (INIS)

    Gu, X N; Zhou, W R; Zheng, Y F; Li, X L; Cheng, Y

    2010-01-01

    Rapidly solidified (RS) Mg-3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s -1 , 30 m s -1 and 45 m s -1 ) with the as-cast Mg-3Ca alloy ingot as a raw material. The RS45 Mg-3Ca alloy ribbon showed a much more fine grain size feature (approximately 200-500 nm) in comparison to the coarse grain size (50-100 μm) of the original as-cast Mg-3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg-3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds (1.43 mm yr -1 for RS15, 0.94 mm yr -1 for RS30 and 0.36 mm yr -1 for RS45). The RS Mg-3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg-3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg-3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells, whereas the as-cast Mg-3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg-3Ca alloy ribbons than that of the as-cast Mg-3Ca alloy ingot.

  20. Application package DeCA. Version 3.3

    International Nuclear Information System (INIS)

    Gladkikh, P.I.; Strelkov, M.A.; Zelinskij, A.Yu.

    1993-01-01

    The application package DeCA (Design of Cyclic Accelerators) is intended for solving a wide range of problems related to the dynamics of charged particle beams in cyclic accelerators and storage rings. It can be used for both design or modification purposes and numerical experimentation. The package DeCA consist of several program blocks, which are unified by functional principle. In this article we are consider the description of two blocks: the control block (COMM), and the description of magnetic elements and lattices block (IMOS). The formats of package commands, language of lattice definition and list of own commands of these blocks are described. (author). 4 refs., 3 ape

  1. Features of the core-valence luminescence and electron energy band structure of A1-xCsxCaCl3 (A = K,Rb) crystals

    International Nuclear Information System (INIS)

    Chornodolskyy, Ya; Stryganyuk, G; Syrotyuk, S; Voloshinovskii, A; Rodnyi, P

    2007-01-01

    From luminescence spectroscopy of CsCaCl 3 , Rb 1-x Cs x CaCl 3 and K 1-x Cs x CaCl 3 crystals, we have found evidence for intrinsic and impurity core-valence luminescence due to the radiative recombination of valence electrons with the holes of intrinsic or impurity 5p Cs + core states. The structural similarity of core-valence luminescence spectra has been revealed for the A 1-x Cs x CaCl 3 (A = K,Rb) crystals investigated. The electron energy structure of the CsCaCl 3 crystal has been calculated using the pseudopotential approach taking into account the gradient corrections for the exchange-correlation energy. The calculated density of the electronic states of CsCaCl 3 has been compared with corresponding parameters obtained from the analysis of core-valence luminescence spectra

  2. 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.

  3. Lowering glucose level elevates [Ca2+]i in hypothalamic arcuate nucleus NPY neurons through P/Q-type Ca2+ channel activation and GSK3β inhibition

    Science.gov (United States)

    Chen, Yu; Zhou, Jun; Xie, Na; Huang, Chao; Zhang, Jun-qi; Hu, Zhuang-li; Ni, Lan; Jin, You; Wang, Fang; Chen, Jian-guo; Long, Li-hong

    2012-01-01

    Aim: To identify the mechanisms underlying the elevation of intracellular Ca2+ level ([Ca2+]i) induced by lowering extracellular glucose in rat hypothalamic arcuate nucleus NPY neurons. Methods: Primary cultures of hypothalamic arcuate nucleus (ARC) neurons were prepared from Sprague-Dawley rats. NPY neurons were identified with immunocytochemical method. [Ca2+]i was measured using fura-2 AM. Ca2+ current was recorded using whole-cell patch clamp recording. AMPK and GSK3β levels were measured using Western blot assay. Results: Lowering glucose level in the medium (from 10 to 1 mmol/L) induced a transient elevation of [Ca2+]i in ARC neurons, but not in hippocampal and cortical neurons. The low-glucose induced elevation of [Ca2+]i in ARC neurons depended on extracellular Ca2+, and was blocked by P/Q-type Ca2+channel blocker ω-agatoxin TK (100 nmol/L), but not by L-type Ca2+ channel blocker nifedipine (10 μmol/L) or N-type Ca2+channel blocker ω-conotoxin GVIA (300 nmol/L). Lowering glucose level increased the peak amplitude of high voltage-activated Ca2+ current in ARC neurons. The low-glucose induced elevation of [Ca2+]i in ARC neurons was blocked by the AMPK inhibitor compound C (20 μmol/L), and enhanced by the GSK3β inhibitor LiCl (10 mmol/L). Moreover, lowering glucose level induced the phosphorylation of AMPK and GSK3β, which was inhibited by compound C (20 μmol/L). Conclusion: Lowering glucose level enhances the activity of P/Q type Ca2+channels and elevates [Ca2+]i level in hypothalamic arcuate nucleus neurons via inhibition of GSK3β. PMID:22504905

  4. The Effect of Increasing Sn Content on High-Temperature Mechanical Deformation of an Mg-3%Cu-1%Ca Alloy

    Directory of Open Access Journals (Sweden)

    Georgios S.E. Antipas

    2013-11-01

    Full Text Available Chill casting of magnesium alloy samples with secondary alloying elements of Cu, Ca and Sn at % w.t. concentrations in the range 1–5, 0.1–5 and 0.13 respectively, gave rise to appreciably enhanced resistance to high-temperature creep, while maintaining good heat conductivity. The latter was considered to be driven by Cu and Mg-Cu intermetallics while it was clear that Sn mediated the high-temperature performance, mainly via networks of Mg2Sn and MgCaSn precipitates along the Mg matrix grain boundaries. It was postulated that Sn formed intermetallics by preferential substitution of Ca atoms and, thus, did not degrade the heat conductivity by retaining Cu. The % w.t. stoichiometry with the optimum combination of heat conductivity and resistance to high-temperature creep was found to be Mg-3Cu-1Ca-0.1Sn.

  5. The Properties of Sintered Calcium Phosphate with [Ca]/[P] = 1.50

    Directory of Open Access Journals (Sweden)

    Moo-Chin Wang

    2012-10-01

    Full Text Available In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD, inductively coupled plasma-mass spectrometry (ICP-MS, Fourier-transform infrared (FT-IR spectra, Vickers hardness indentation and scanning electron microscopy (SEM. When the pellet samples were sintered between 700 °C and 1200 °C for 4 h, the hydroxyapatite (Ca10(PO46(OH2, HA still maintained the major phase, accompanied with the rhenanite (NaCaPO4 as the secondary phase and β-tricalcium phosphate (β-Ca3(PO42, β-TCP as the minor phases. In addition, the HA partially transformed to α-tricalcium phosphate (α-Ca3(PO42, α-TCP and tetracalcium phosphate (Ca4(PO42O, TTCP, when the pellet samples were sintered at 1300 °C and 1400 °C, respectively, for 4 h. The maximum density and Vickers Hardness (HV of sintered pellet samples were 2.85 g/cm3 (90.18% theoretical density (T.D. and 407, which appeared at 1200 °C and 900 °C, respectively.

  6. Synthesis, microstructure and EPR of CaMnO{sub 3} and Eu{sub x}Ca{sub 1-x}MnO{sub 3} manganite, obtained by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Santiago T, M.; Hernandez C, L.; Legorreta G, F. [Universidad Autonoma del Estado de Hidalgo, AACTyM, Carretera Pachuca-Tulancingo Km 4.5, 42074 Pachuca, Hidalgo (Mexico); Montiel S, H. [UNAM, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Departamento de Tecnociencias, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Alvarez L, G. [IPN, Escuela Superior de Fisica y Matematicas, Departamento de Fisica, U. P. Adolfo Lopez Mateos, Edif. 9, Col. Lindavista, 07738 Mexico D. F. (Mexico); Flores G, M. A., E-mail: mar200878@hotmail.com [Universidad Politecnica de Pachuca, Laboratorio de Nanotecnologia y Bioelectromagnetismo Aplicado, Carretera Pachuca-Cd. Sahagun Km 20, Ex-Hacienda de Santa Barbara, 43830 Zempoala, Hidalgo (Mexico)

    2011-07-01

    The synthesis of CaMnO{sub 3} and Eu{sub x}Ca{sub 1-x}MnO{sub 3} obtained by coprecipitation method is showed. The synthesized samples were characterized by X-ray diffraction and scanning electronic microscopy, the powders showed orthorhombic structure and pnma space group. When it was doped with Europium, their morphology tendency was spherical. Measurements were carried out on electron paramagnetic resonance (EPR) with constant frequency = 9.4 GHz (band X) and dc magnetic field (H dc) 0-0.8 T, measurements were at 300 K and 77 K. EPR spectra showed significant differences between both samples, indicating that the substitution of divalent alkaline earth cations by trivalent rare earth ions, allowing the formation of a mixed valence state of manganese, Mn{sup 3+} and Mn{sup 4+}. A 77 K, the manganite of concentration x = 0.30 had a magnetic ordering, noted by the presence of hysteresis. (Author)

  7. PLCζ Induced Ca2+ Oscillations in Mouse Eggs Involve a Positive Feedback Cycle of Ca2+ Induced InsP3 Formation From Cytoplasmic PIP2

    Science.gov (United States)

    Sanders, Jessica R.; Ashley, Bethany; Moon, Anna; Woolley, Thomas E.; Swann, Karl

    2018-01-01

    Egg activation at fertilization in mammalian eggs is caused by a series of transient increases in the cytosolic free Ca2+ concentration, referred to as Ca2+ oscillations. It is widely accepted that these Ca2+ oscillations are initiated by a sperm derived phospholipase C isoform, PLCζ that hydrolyses its substrate PIP2 to produce the Ca2+ releasing messenger InsP3. However, it is not clear whether PLCζ induced InsP3 formation is periodic or monotonic, and whether the PIP2 source for generating InsP3 from PLCζ is in the plasma membrane or the cytoplasm. In this study we have uncaged InsP3 at different points of the Ca2+ oscillation cycle to show that PLCζ causes Ca2+ oscillations by a mechanism which requires Ca2+ induced InsP3 formation. In contrast, incubation in Sr2+ media, which also induces Ca2+ oscillations in mouse eggs, sensitizes InsP3-induced Ca2+ release. We also show that the cytosolic level Ca2+ is a key factor in setting the frequency of Ca2+ oscillations since low concentrations of the Ca2+ pump inhibitor, thapsigargin, accelerates the frequency of PLCζ induced Ca2+ oscillations in eggs, even in Ca2+ free media. Given that Ca2+ induced InsP3 formation causes a rapid wave during each Ca2+ rise, we use a mathematical model to show that InsP3 generation, and hence PLCζ's substate PIP2, has to be finely distributed throughout the egg cytoplasm. Evidence for PIP2 distribution in vesicles throughout the egg cytoplasm is provided with a rhodamine-peptide probe, PBP10. The apparent level of PIP2 in such vesicles could be reduced by incubating eggs in the drug propranolol which also reversibly inhibited PLCζ induced, but not Sr2+ induced, Ca2+ oscillations. These data suggest that the cytosolic Ca2+ level, rather than Ca2+ store content, is a key variable in setting the pace of PLCζ induced Ca2+ oscillations in eggs, and they imply that InsP3 oscillates in synchrony with Ca2+ oscillations. Furthermore, they support the hypothesis that PLCζ and sperm

  8. PIK3CA activating mutation in colorectal carcinoma: associations with molecular features and survival.

    Directory of Open Access Journals (Sweden)

    Christophe Rosty

    Full Text Available Mutations in PIK3CA are present in 10 to 15% of colorectal carcinomas. We aimed to examine how PIK3CA mutations relate to other molecular alterations in colorectal carcinoma, to pathologic phenotype and survival. PIK3CA mutation testing was carried out using direct sequencing on 757 incident tumors from the Melbourne Collaborative Cohort Study. The status of O-6-methylguanine-DNA methyltransferase (MGMT was assessed using both immunohistochemistry and methyLight techniques. Microsatellite instability, CpG island phenotype (CIMP, KRAS and BRAF V600E mutation status, and pathology review features were derived from previous reports. PIK3CA mutation was observed in 105 of 757 (14% of carcinomas, characterized by location in the proximal colon (54% vs. 34%; P<0.001 and an increased frequency of KRAS mutation (48% vs. 25%; P<0.001. High-levels of CIMP were more frequently found in PIK3CA-mutated tumors compared with PIK3CA wild-type tumors (22% vs. 11%; P = 0.004. There was no difference in the prevalence of BRAF V600E mutation between these two tumor groups. PIK3CA-mutated tumors were associated with loss of MGMT expression (35% vs. 20%; P = 0.001 and the presence of tumor mucinous differentiation (54% vs. 32%; P<0.001. In patients with wild-type BRAF tumors, PIK3CA mutation was associated with poor survival (HR 1.51 95% CI 1.04-2.19, P = 0.03. In summary, PIK3CA-mutated colorectal carcinomas are more likely to develop in the proximal colon, to demonstrate high levels of CIMP, KRAS mutation and loss of MGMT expression. PIK3CA mutation also contributes to significantly decreased survival for patients with wild-type BRAF tumors.

  9. Microstructure, biocorrosion and cytotoxicity evaluations of rapid solidified Mg-3Ca alloy ribbons as a biodegradable material

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X N; Zhou, W R; Zheng, Y F [State Key Laboratory for Turbulence and Complex System and Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Li, X L [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Cheng, Y, E-mail: yfzheng@pku.edu.c [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2010-06-01

    Rapidly solidified (RS) Mg-3Ca alloy ribbons were prepared by the melt-spinning technique at different wheel rotating speeds (15 m s{sup -1}, 30 m s{sup -1} and 45 m s{sup -1}) with the as-cast Mg-3Ca alloy ingot as a raw material. The RS45 Mg-3Ca alloy ribbon showed a much more fine grain size feature (approximately 200-500 nm) in comparison to the coarse grain size (50-100 {mu}m) of the original as-cast Mg-3Ca alloy ingot. The corrosion electrochemical tests in simulated body fluid indicated that the corrosion rate of the as-cast Mg-3Ca alloy was strongly reduced by the RS procedure and tended to be further decreased with increasing wheel rotating speeds (1.43 mm yr{sup -1} for RS15, 0.94 mm yr{sup -1} for RS30 and 0.36 mm yr{sup -1} for RS45). The RS Mg-3Ca alloy ribbons showed more uniform corrosion morphology compared with the as-cast Mg-3Ca alloy after polarization. The cytotoxicity evaluation revealed that the three experimental as-spun Mg-3Ca alloy ribbon extracts did not induce toxicity to the L-929 cells, whereas the as-cast Mg-3Ca alloy ingot extract did. The L-929 cells showed more improved adhesion on the surfaces of the three as-spun Mg-3Ca alloy ribbons than that of the as-cast Mg-3Ca alloy ingot.

  10. In situ observation of electron beam-induced phase transformation of CaCO3 to CaO via ELNES at low electron beam energies.

    Science.gov (United States)

    Golla-Schindler, Ute; Benner, Gerd; Orchowski, Alexander; Kaiser, Ute

    2014-06-01

    It is demonstrated that energy-filtered transmission electron microscope enables following of in situ changes of the Ca-L2,3 edge which can originate from variations in both local symmetry and bond lengths. Low accelerating voltages of 20 and 40 kV slow down radiation damage effects and enable study of the start and finish of phase transformations. We observed electron beam-induced phase transformation of single crystalline calcite (CaCO3) to polycrystalline calcium oxide (CaO) which occurs in different stages. The coordination of Ca in calcite is close to an octahedral one streched along the direction. Changes during phase transformation to an octahedral coordination of Ca in CaO go along with a bond length increase by 5 pm, where oxygen is preserved as a binding partner. Electron loss near-edge structure of the Ca-L2,3 edge show four separated peaks, which all shift toward lower energies during phase transformation at the same time the energy level splitting increases. We suggest that these changes can be mainly addressed to the change of the bond length on the order of picometers. An important pre-condition for such studies is stability of the energy drift in the range of meV over at least 1 h, which is achieved with the sub-Ångström low-voltage transmission electron microscope I prototype microscope.

  11. A novel approach in preparing polymer/nano-CaCO3 composites

    Institute of Scientific and Technical Information of China (English)

    Zhengying LIU; Runze YU; Mingbo YANG; Jianmin FENG; Wei YANG; Bo YIN

    2008-01-01

    An novel compounding process using nano-CaCO3 aqueous suspension for preparing polymer/ nano-CaCO3 composites with nanoparticles dispersed at the nanoscale is reported. The process is called the mild mixing method. In this method, the pre-dispersed nano-particle suspensions are blended with melting polymers in a weak shearing field using an extruder, followed by removing the water from the vent. The four typical poly-meric nanocomposites were prepared by mild mixing method. The dispersion of nano-CaCO3 in the matrix of the polymer at the nanoscale was confirmed by scanning electron microscopy (SEM). The molecular weights of polycarbonate (PC) and its nanocomposite showed that the degradation had not occurred during the mild mixing processing. The mechanical properties of the composite with 1.5 wt-% nano-CaCO3 improve slightly. It proved that this approach is suitable for the preparation of nano-composites based on both polar and non-polar polymers.

  12. Structural and compositional characterization of synthetic (Ca,Sr)-tremolite and (Ca,Sr)-diopside solid solutions

    Science.gov (United States)

    Gottschalk, M.; Najorka, J.; Andrut, M.

    Tremolite (CaxSr1-x)2Mg5[Si8O22/(OH)2] and diopside (CaxSr1-x)Mg[Si2O6] solid solutions have been synthesized hydrothermally in equilibrium with a 1 molar (Ca,Sr)Cl2 aqueous solution at 750°C and 200 MPa. The solid run products have been investigated by optical, electron scanning and high resolution transmission electron microscopy, electron microprobe, X-ray-powder diffraction and Fourier-transform infrared spectroscopy. The synthesized (Ca,Sr)-tremolites are up to 2000 µm long and 30 µm wide, the (Ca,Sr)-diopsides are up to 150 µm long and 20 µm wide. In most runs the tremolites and diopsides are well ordered and chain multiplicity faults are rare. Nearly pure Sr-tremolite (tr0.02Sr-tr0.98) and Sr-diopside (di0.01Sr-di0.99) have been synthesized. A continuous solid solution series, i.e. complete substitution of Sr2+ for Ca2+ on M4-sites exists for (Ca,Sr)-tremolite. Total substitution of Sr2+ for Ca2+ on M2-sites can be assumed for (Ca,Sr)-diopsides. For (Ca,Sr)-tremolites the lattice parameters a, b and β are linear functions of composition and increase with Sr-content whereas c is constant. For the diopside series all 4 lattice parameters are a linear function of composition; a, b, c increase and β decreases with rising Sr-content. The unit cell volume for tremolite increases 3.47% from 906.68 Å3 for tremolite to 938.21 Å3 for Sr-tremolite. For diopside the unit cell volume increases 4.87 % from 439.91 Å3 for diopside to 461.30 Å3 for Sr-diopside. The observed splitting of the OH stretching band in tremolite is caused by different configurations of the next nearest neighbors (multi mode behavior). Resolved single bands can be attributed to the following configurations on the M4-sites: SrSr, SrCa, CaCa and CaMg. The peak positions of these 4 absorption bands are a linear function of composition. They are shifted to lower wavenumbers with increasing Sr-content. No absorption band due to the SrMg configuration on the M4-site is observed. This indicates

  13. Facile combustion synthesis of novel CaZrO 3

    Indian Academy of Sciences (India)

    Abstract. A facile sol–gel combustion route was reported for the direct preparation of CaZrO3:Eu3+ and CaZrO3:Eu3+, Gd3+. The obtained deposits were characterized by XRD, TGA-DSC, SEM, EDS, PL measurements and microscope fluorescence. When the Gd3+ ions were introduced in this compound, the emissions of ...

  14. Radiolysis of Ca14CO3

    International Nuclear Information System (INIS)

    Sanchez, M.G.A.

    1986-01-01

    The partition-ion exclusion chromatography is evaluated to analyse non-ionic organic compounds obtained from radiolysis of high specific activity Ca 14 CO 3 . The Ca 14 CO 3 was irradiated by β - decay of carbon-14 or by γ rays from a cobalt-60 source. The crystals were dissolved for qualitative and quantitative analysis of the radiolytic products. Formic and oxalic acids were produced in high yields. Glyoxylic, acetic and glycolic acids, formaldehyde and methanol were produced in low yields. Quantitative determination was carried out by liquid scintillation spectroscopy and the chemical yields (G-values) were calculated for the products. Mechanisms of product formation are proposed based on thermal annealing experiments. (Author) [pt

  15. Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) interacts with neurofilament L and inhibits its filament association

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Hana [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Katoh, Tsuyoshi [Department of Biochemistry, Asahikawa Medical University, Asahikawa, 078-8510 (Japan); Nakagawa, Ryoko; Ishihara, Yasuhiro [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Sueyoshi, Noriyuki; Kameshita, Isamu [Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795 (Japan); Taniguchi, Takanobu [Department of Biochemistry, Asahikawa Medical University, Asahikawa, 078-8510 (Japan); Hirano, Tetsuo; Yamazaki, Takeshi [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Ishida, Atsuhiko, E-mail: aishida@hiroshima-u.ac.jp [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan)

    2016-09-02

    Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) is a Ser/Thr phosphatase that belongs to the PPM family. Growing evidence suggests that PPM phosphatases including CaMKP act as a complex with other proteins to regulate cellular functions. In this study, using the two-dimensional far-western blotting technique with digoxigenin-labeled CaMKP as a probe, in conjunction with peptide mass fingerprinting analysis, we identified neurofilament L (NFL) as a CaMKP-binding protein in a Triton-insoluble fraction of rat brain. We confirmed binding of fluorescein-labeled CaMKP (F-CaMKP) to NFL in solution by fluorescence polarization. The analysis showed that the dissociation constant of F-CaMKP for NFL is 73 ± 17 nM (n = 3). Co-immunoprecipitation assay using a cytosolic fraction of NGF-differentiated PC12 cells showed that endogenous CaMKP and NFL form a complex in cells. Furthermore, the effect of CaMKP on self-assembly of NFL was examined. Electron microscopy revealed that CaMKP markedly prevented NFL from forming large filamentous aggregates, suggesting that CaMKP-binding to NFL inhibits its filament association. These findings may provide new insights into a novel mechanism for regulating network formation of neurofilaments during neuronal differentiation. - Highlights: • NFL was identified as a CaMKP-binding protein in an insoluble fraction of rat brain. • CaMKP bound to NFL in solution with a K{sub d} value of 73 ± 17 nM. • A CaMKP-NFL complex was found in NGF-differentiated PC12 cells. • CaMKP-binding to NFL inhibited its filament association. • CaMKP may regulate network formation of neurofilaments in neurons.

  16. Effects of Calcium Source on Biochemical Properties of Microbial CaCO3 Precipitation.

    Science.gov (United States)

    Xu, Jing; Du, Yali; Jiang, Zhengwu; She, Anming

    2015-01-01

    The biochemical properties of CaCO3 precipitation induced by Sporosarcina pasteurii, an ureolytic type microorganism, were investigated. Effects of calcium source on the precipitation process were examined, since calcium source plays a key role in microbiologically induced mineralization. Regardless of the calcium source type, three distinct stages in the precipitation process were identified by Ca(2+), NH4 (+), pH and cell density monitoring. Compared with stage 1 and 3, stage 2 was considered as the most critical part since biotic CaCO3 precipitation occurs during this stage. Kinetics studies showed that the microbial CaCO3 precipitation rate for calcium lactate was over twice of that for calcium nitrate, indicating that calcium lactate is more beneficial for the cell activity, which in turn determines urease production and CaCO3 precipitation. X-ray diffraction analysis confirmed the CaCO3 crystal as calcite, although scanning electron microscopy revealed a difference in crystal size and morphology if calcium source was different. The findings of this paper further suggest a promising application of microbiologically induced CaCO3 precipitation in remediation of surface and cracks of porous media, e.g., cement-based composites, particularly by using organic source of calcium lactate.

  17. caGrid 1.0: a Grid enterprise architecture for cancer research.

    Science.gov (United States)

    Oster, Scott; Langella, Stephen; Hastings, Shannon; Ervin, David; Madduri, Ravi; Kurc, Tahsin; Siebenlist, Frank; Covitz, Peter; Shanbhag, Krishnakant; Foster, Ian; Saltz, Joel

    2007-10-11

    caGrid is the core Grid architecture of the NCI-sponsored cancer Biomedical Informatics Grid (caBIG) program. The current release, caGrid version 1.0, is developed as the production Grid software infrastructure of caBIG. Based on feedback from adopters of the previous version (caGrid 0.5), it has been significantly enhanced with new features and improvements to existing components. This paper presents an overview of caGrid 1.0, its main components, and enhancements over caGrid 0.5.

  18. Neuronal migration and its disorders affecting the CA3 region

    Directory of Open Access Journals (Sweden)

    Richard eBelvindrah

    2014-03-01

    Full Text Available In this review, we focus on CA3 neuronal migration disorders in the rodent. We begin by introducing the main steps of hippocampal development, and we summarize characteristic hippocampal malformations in human. We then describe various mouse mutants showing structural hippocampal defects. Notably, genes identified in human cortical neuronal migration disorders consistently give rise to a CA3 phenotype when mutated in the mouse. We successively describe their molecular, physiological and behavioral phenotypes that together contribute to a better understanding of CA3-dependent functions. We finally discuss potential factors underlying the CA3 vulnerability revealed by these mouse mutants and that may also contribute to other human neurological and psychiatric disorders.

  19. Determination of standard Gibbs free energy of formation for Ca2P2O7 and Ca(PO3)2 from solid-state EMF measurements using yttria stabilised zirconia as solid electrolyte

    International Nuclear Information System (INIS)

    Sandstroem, Malin Hannah; Bostroem, Dan; Rosen, Erik

    2006-01-01

    The equilibrium reactions: 3Ca 2 P 2 O 7 (s)+6Ni(s)-bar 2Ca 3 (PO 4 ) 2 (s)+2Ni 3 P(s)+52O 2 (g) and 2Ca(PO 3 ) 2 (s)+6Ni(s)-bar Ca 2 P 2 O 7 (s)+2Ni 3 P(s)+52O 2 (g) were studied in the temperature range 890K to 1140K. The oxygen equilibrium pressures were determined using galvanic cells incorporating yttria stabilized zirconia as solid electrolyte. From the measured data and using the literature values of standard Gibbs free energy of formation for Ca 3 (PO 4 ) 2 and Ni 3 P, the following relationship of the standard Gibbs free energy of formation for Ca 2 P 2 O 7 and Ca(PO 3 ) 2 were calculated:Δ f G o (Ca 2 P 2 O 7 )+/-11/(kJ.mol -1 )=-3475.9+1.5441(T/K)-0.1051(T/K).ln(T/K)andΔ f G o (Ca(PO 3 ) 2 )+/-12/(kJ.mol -1 )=-3334.8+6.1561(T/K)-0.6950(T/K).ln(T/K)

  20. The 15th Internatonal Conference Quality in Resarch (Qir) 2017 Preparation and Ionic Conductivity of Li3.9Ca0.1Ti5O12 Using Waste Chicken Eggshells as ca Source for Anode Material of Lithium-Ion Batteries

    Science.gov (United States)

    Subhan, Achmad; Setiawan, Dedy; Ahmiatri Saptari, Sitti

    2018-03-01

    Li3.9Ca0.1Ti5O12 has been synthesized as anode material for lithium-ion batteries parallel with Li4Ti5O12 anode material using solid state reaction method in an air atmosphere. LiOH.H2O, TiO2, and waste chicken eggshells in the form of CaCO3 were chosen as sources of Li, Ti, and Ca respectively and prepared using stoichiometric. The phase structure, morphology, and electrochemical impedance of as-prepared samples were characterized using XRD, SEM, and EIS. The XRD characterization revealed that in Li3.9Ca0.1Ti5O12 sample, all amount of dopant had entered the lattice structure of Li4Ti5O12. The EDX image also detect the existence of Ca in the structure of Li3.9Ca0.1Ti5O12. The EIS characterization revealed that the Li3.9Ca0.1Ti5O12 sample had lower electrochemical impedance compared to the Li4Ti5O12 sample. The diffusion coefficient were obtained by Faraday’s method, and exhibited that the Li3.9Ca0.1Ti5O12 sample (1.46986 × 10-12 cm2/s) had higher ionic conductivity than the Li4Ti5O12 sample (4.40995 × 10-16 cm2/s). According to the cycle performance test, the Li3.9Ca0.1Ti5O12 sample also had higher charge-discharge capacity and stability compared to the Li4Ti5O12 sample.

  1. Encoding, Consolidation, and Retrieval of Contextual Memory: Differential Involvement of Dorsal CA3 and CA1 Hippocampal Subregions

    Science.gov (United States)

    Daumas, Stephanie; Halley, Helene; Frances, Bernard; Lassalle, Jean-Michel

    2005-01-01

    Studies on human and animals shed light on the unique hippocampus contributions to relational memory. However, the particular role of each hippocampal subregion in memory processing is still not clear. Hippocampal computational models and theories have emphasized a unique function in memory for each hippocampal subregion, with the CA3 area acting…

  2. Intracellular alkalinization induces cytosolic Ca2+ increases by inhibiting sarco/endoplasmic reticulum Ca2+-ATPase (SERCA.

    Directory of Open Access Journals (Sweden)

    Sen Li

    Full Text Available Intracellular pH (pHi and Ca(2+ regulate essentially all aspects of cellular activities. Their inter-relationship has not been mechanistically explored. In this study, we used bases and acetic acid to manipulate the pHi. We found that transient pHi rise induced by both organic and inorganic bases, but not acidification induced by acid, produced elevation of cytosolic Ca(2+. The sources of the Ca(2+ increase are from the endoplasmic reticulum (ER Ca(2+ pools as well as from Ca(2+ influx. The store-mobilization component of the Ca(2+ increase induced by the pHi rise was not sensitive to antagonists for either IP(3-receptors or ryanodine receptors, but was due to inhibition of the sarco/endoplasmic reticulum Ca(2+-ATPase (SERCA, leading to depletion of the ER Ca(2+ store. We further showed that the physiological consequence of depletion of the ER Ca(2+ store by pHi rise is the activation of store-operated channels (SOCs of Orai1 and Stim1, leading to increased Ca(2+ influx. Taken together, our results indicate that intracellular alkalinization inhibits SERCA activity, similar to thapsigargin, thereby resulting in Ca(2+ leak from ER pools followed by Ca(2+ influx via SOCs.

  3. FGFR3, PIK3CA and RAS mutations in benign lichenoid keratosis.

    Science.gov (United States)

    Groesser, L; Herschberger, E; Landthaler, M; Hafner, C

    2012-04-01

    Benign lichenoid keratoses (BLKs) are solitary skin lesions which have been proposed to represent a regressive form of pre-existent epidermal tumours such as solar lentigo or seborrhoeic keratosis. However, the genetic basis of BLK is unknown. FGFR3, PIK3CA and RAS mutations have been shown to be involved in the pathogenesis of seborrhoeic keratosis and solar lentigo. We thus investigated whether these mutations are also present in BLK. After manual microdissection and DNA isolation, 52 BLKs were screened for FGFR3, PIK3CA and RAS hotspot mutations using SNaPshot(®) multiplex assays. We identified 6/52 (12%) FGFR3 mutations, 10/52 (19%) PIK3CA mutations, 6/52 (12%) HRAS mutations and 2/52 (4%) KRAS mutations. FGFR3 and RAS mutations were mutually exclusive. One BLK showed a simultaneous PIK3CA and HRAS mutation. In nine BLKs with a mutation, nonlesional control tissue from the epidermal margin and the dermal lymphocytic infiltrate were wild-type, indicating that these mutations are somatic. To demonstrate that these findings are specific, 10 samples of lichen planus were analysed without evidence for FGFR3, PIK3CA or RAS mutations. Our results indicate that FGFR3, PIK3CA and RAS mutations are present in approximately 50% of BLKs. These findings support the concept on the molecular genetic level that at least a proportion of BLKs represents regressive variants resulting from former benign epidermal tumours such as seborrhoeic keratosis and solar lentigo. © 2011 The Authors. BJD © 2011 British Association of Dermatologists 2011.

  4. Orai1 mediates exacerbated Ca(2+ entry in dystrophic skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhao

    Full Text Available There is substantial evidence indicating that disruption of Ca(2+ homeostasis and activation of cytosolic proteases play a key role in the pathogenesis and progression of Duchenne Muscular Dystrophy (DMD. However, the exact nature of the Ca(2+ deregulation and the Ca(2+ signaling pathways that are altered in dystrophic muscles have not yet been resolved. Here we examined the contribution of the store-operated Ca(2+ entry (SOCE for the pathogenesis of DMD. RT-PCR and Western blot found that the expression level of Orai1, the pore-forming unit of SOCE, was significantly elevated in the dystrophic muscles, while parallel increases in SOCE activity and SR Ca(2+ storage were detected in adult mdx muscles using Fura-2 fluorescence measurements. High-efficient shRNA probes against Orai1 were delivered into the flexor digitorum brevis muscle in live mice and knockdown of Orai1 eliminated the differences in SOCE activity and SR Ca(2+ storage between the mdx and wild type muscle fibers. SOCE activity was repressed by intraperitoneal injection of BTP-2, an Orai1 inhibitor, and cytosolic calpain1 activity in single muscle fibers was measured by a membrane-permeable calpain substrate. We found that BTP-2 injection for 2 weeks significantly reduced the cytosolic calpain1 activity in mdx muscle fibers. Additionally, ultrastructural changes were observed by EM as an increase in the number of triad junctions was identified in dystrophic muscles. Compensatory changes in protein levels of SERCA1, TRP and NCX3 appeared in the mdx muscles, suggesting that comprehensive adaptations occur following altered Ca(2+ homeostasis in mdx muscles. Our data indicates that upregulation of the Orai1-mediated SOCE pathway and an overloaded SR Ca(2+ store contributes to the disrupted Ca(2+ homeostasis in mdx muscles and is linked to elevated proteolytic activity, suggesting that targeting Orai1 activity may be a promising therapeutic approach for the prevention and treatment of

  5. High pressure study of low compressibility tetracalcium aluminum carbonate hydrates 3CaO·Al2O3·CaCO3·11H2O

    KAUST Repository

    Moon, Juhyuk; Oh, Jae Eun; Balonis, Magdalena; Glasser, Fredrik P.; Clark, Simon M.; Monteiro, Paulo J.M.

    2012-01-01

    Synchrotron X-ray diffraction data was collected from a sample of monocarboaluminate 3CaO•Al2O3CaCO 3•11H2O from ambient pressure to 4.3 GPa. The refined crystal structure at ambient pressure is triclinic with parameters a = 5.77(2) Å, b = 8

  6. The hippocampal CA2 ensemble is sensitive to contextual change.

    Science.gov (United States)

    Wintzer, Marie E; Boehringer, Roman; Polygalov, Denis; McHugh, Thomas J

    2014-02-19

    Contextual learning involves associating cues with an environment and relating them to past experience. Previous data indicate functional specialization within the hippocampal circuit: the dentate gyrus (DG) is crucial for discriminating similar contexts, whereas CA3 is required for associative encoding and recall. Here, we used Arc/H1a catFISH imaging to address the contribution of the largely overlooked CA2 region to contextual learning by comparing ensemble codes across CA3, CA2, and CA1 in mice exposed to familiar, altered, and novel contexts. Further, to manipulate the quality of information arriving in CA2 we used two hippocampal mutant mouse lines, CA3-NR1 KOs and DG-NR1 KOs, that result in hippocampal CA3 neuronal activity that is uncoupled from the animal's sensory environment. Our data reveal largely coherent responses across the CA axis in control mice in purely novel or familiar contexts; however, in the mutant mice subject to these protocols the CA2 response becomes uncoupled from CA1 and CA3. Moreover, we show in wild-type mice that the CA2 ensemble is more sensitive than CA1 and CA3 to small changes in overall context. Our data suggest that CA2 may be tuned to remap in response to any conflict between stored and current experience.

  7. Serotonin Regulates the Firing of Principal Cells of the Subiculum by Inhibiting a T-type Ca(2+) Current

    DEFF Research Database (Denmark)

    Petersen, Anders V; Jensen, Camilla S; Crépel, Valérie

    2017-01-01

    The subiculum is the main output of the hippocampal formation. A high proportion of its principal neurons fire action potentials in bursts triggered by the activation of low threshold calcium currents. This firing pattern promotes synaptic release and regulates spike-timing-dependent plasticity. ...... of epileptiform discharges induced in in vitro models for temporal lobe epilepsy (TLE)....

  8. Effect of Ca{sup 2+} substitution on impedance and electrical conduction mechanism of Ba{sub 1−x}Ca{sub x}Zr{sub 0.1}Ti{sub 0.9}O{sub 3} (0.00≤x≤0.20) ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Tanusree [Functional Ceramics Laboratory, Department of Applied Physics, Indian Institute of Technology (ISM), Dhanbad 826004 (India); Das, Sayantani [Department of Physics, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700009 (India); Badapanda, T. [Department of Physics, C.V. Raman College of Engineering, Bhubaneswar, Odisha 7520544 (India); Sinha, T.P. [Department of Physics, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata 700009 (India); Sarun, P.M., E-mail: sarun.res@gmail.com [Functional Ceramics Laboratory, Department of Applied Physics, Indian Institute of Technology (ISM), Dhanbad 826004 (India)

    2017-03-01

    The Ca modified Ba{sub 1−x}Ca{sub x}Zr{sub 0.1}Ti{sub 0.9}O{sub 3} (BCZT) system for x=0.00–0.20 is synthesized by the high-temperature conventional solid state reaction method. The morphotropic phase boundary (MPB) between the tetragonal and cubic structure is obtained at room temperature for the composition x=0.15. The doping of Ca facilitates the enhancement of the homogeneity of microstructure and growth of the grain size. The phase transition is also confirmed by Raman spectroscopy. In order to explore the effect of Ca concentration variation on the conduction mechanism of BaZr{sub 0.1}Ti{sub 0.9}O{sub 3} (BZT) ceramic, the frequency dependent ac impedance spectroscopy technique is used at various temperatures. The effect of Ca doping on the electrical properties of BZT is clearly noticeable. The resistance of the grain (bulk) and the grain boundary is increased as a consequence of the increase in the activation energy of Ca substituted BZT samples. The enhanced resistivity of the Ca substituted BZT ceramics is explained in terms of the decrease in the mobility of the charge carriers associated with the lattice distortion. The electric modulus analysis reveals the enhanced capacitance of BCZT ceramics which is in good agreement with the results obtained from complex impedance analysis.

  9. Physical conditions in CaFe interstellar clouds

    OpenAIRE

    Gnacinski, P.; Krogulec, M.

    2007-01-01

    Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.

  10. Regulation of Blood Pressure by Targeting CaV1.2-Galectin-1 Protein Interaction.

    Science.gov (United States)

    Hu, Zhenyu; Li, Guang; Wang, Jiong-Wei; Chong, Suet Yen; Yu, Dejie; Wang, Xiaoyuan; Soon, Jia Lin; Liang, Mui Cheng; Wong, Yuk Peng; Huang, Na; Colecraft, Henry M; Liao, Ping; Soong, Tuck Wah

    2018-04-12

    Background -L-type Ca V 1.2 channels play crucial roles in regulation of blood pressure. Galectin-1 (Gal-1), has been reported to bind to the I-II loop of Ca V 1.2 channels to reduce their current density. However, the mechanistic understanding for the down-regulation of Ca V 1.2 channels by Gal-1, and whether Gal-1 plays a direct role in blood pressure regulation remain unclear. Methods - In vitro experiments involving co-IP, western blot, patch-clamp recordings, immunohistochemistry and pressure myography were used to evaluate the molecular mechanisms by which Gal-1 down-regulates Ca V 1.2 channel in transfected HEK 293 cells, smooth muscle cells, arteries from Lgasl1 -/- mice, rat and human patients. In vivo experiments involving delivery of Tat-e9c peptide and AAV5-Gal-1 into rats were performed to investigate the effect of targeting Ca V 1.2-Gal-1 interaction on blood pressure monitored by tail cuff or telemetry methods. Results -Our study reveals that Gal-1 is a key regulator for proteasomal degradation of Ca V 1.2 channels. Gal-1 competed allosterically with Ca V β subunit for binding to the I-II loop of Ca V 1.2 channel. This competitive disruption of Ca V β binding led to Ca V 1.2 degradation by exposing the channels to poly-ubiquitination. Notably, we demonstrated that the inverse relationship of reduced Gal-1 and increased Ca V 1.2 protein levels in arteries was associated with hypertension in hypertensive rats and patients, and Gal-1 deficiency induces higher blood pressure in mice due to up-regulated Ca V 1.2 protein level in arteries. To directly regulate blood pressure by targeting the Ca V 1.2-Gal-1 interaction, we administered Tat-e9c, a peptide that competed for binding of Gal-1, by a mini-osmotic pump and this specific disruption of Ca V 1.2-Gal-1 coupling increased smooth muscle Ca V 1.2 currents, induced larger arterial contraction and caused hypertension in rats. In contrasting experiments, over-expression of Gal-1 in smooth muscle by a

  11. High-pressure compressibility and vibrational properties of (Ca,Mn)CO 3

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jin; Caracas, Razvan; Fan, Dawei; Bobocioiu, Ema; Zhang, Dongzhou; Mao, Wendy L.

    2016-12-01

    Knowledge of potential carbon carriers such as carbonates is critical for our understanding of the deep-carbon cycle and related geological processes within the planet. Here we investigated the high-pressure behavior of (Ca,Mn)CO3 up to 75 GPa by synchrotron single-crystal X-ray diffraction, laser Raman spectroscopy, and theoretical calculations. MnCO3-rich carbonate underwent a structural phase transition from the CaCO3-I structure into the CaCO3-VI structure at 45–48 GPa, while CaCO3-rich carbonate transformed into CaCO3-III and CaCO3-VI at approximately 2 and 15 GPa, respectively. The equation of state and vibrational properties of MnCO3-rich and CaCO3-rich carbonates changed dramatically across the phase transition. The CaCO3-VI-structured CaCO3-rich and MnCO3-rich carbonates were stable at room temperature up to at least 53 and 75 GPa, respectively. The addition of smaller cations (e.g., Mn2+, Mg2+, and Fe2+) can enlarge the stability field of the CaCO3-I phase as well as increase the pressure of the structural transition into the CaCO3-VI phase.

  12. Local Ca²+ entry via Orai1 regulates plasma membrane recruitment of TRPC1 and controls cytosolic Ca²+ signals required for specific cell functions.

    Directory of Open Access Journals (Sweden)

    Kwong Tai Cheng

    2011-03-01

    Full Text Available Store-operated Ca²+ entry (SOCE has been associated with two types of channels: CRAC channels that require Orai1 and STIM1 and SOC channels that involve TRPC1, Orai1, and STIM1. While TRPC1 significantly contributes to SOCE and SOC channel activity, abrogation of Orai1 function eliminates SOCE and activation of TRPC1. The critical role of Orai1 in activation of TRPC1-SOC channels following Ca²+ store depletion has not yet been established. Herein we report that TRPC1 and Orai1 are components of distinct channels. We show that TRPC1/Orai1/STIM1-dependent I(SOC, activated in response to Ca²+ store depletion, is composed of TRPC1/STIM1-mediated non-selective cation current and Orai1/STIM1-mediated I(CRAC; the latter is detected when TRPC1 function is suppressed by expression of shTRPC1 or a STIM1 mutant that lacks TRPC1 gating, STIM1(⁶⁸⁴EE⁶⁸⁵. In addition to gating TRPC1 and Orai1, STIM1 mediates the recruitment and association of the channels within ER/PM junctional domains, a critical step in TRPC1 activation. Importantly, we show that Ca²+ entry via Orai1 triggers plasma membrane insertion of TRPC1, which is prevented by blocking SOCE with 1 µM Gd³+, removal of extracellular Ca²+, knockdown of Orai1, or expression of dominant negative mutant Orai1 lacking a functional pore, Orai1-E106Q. In cells expressing another pore mutant of Orai1, Orai1-E106D, TRPC1 trafficking is supported in Ca²+-containing, but not Ca²+-free, medium. Consistent with this, I(CRAC is activated in cells pretreated with thapsigargin in Ca²+-free medium while I(SOC is activated in cells pretreated in Ca²+-containing medium. Significantly, TRPC1 function is required for sustained K(Ca activity and contributes to NFκB activation while Orai1 is sufficient for NFAT activation. Together, these findings reveal an as-yet unidentified function for Orai1 that explains the critical requirement of the channel in the activation of TRPC1 following Ca²+ store

  13. Ca and Mg binding induce conformational stability of Calfumirin-1 ...

    Indian Academy of Sciences (India)

    The thermal unfolding curves of wtCAF-1 monitored at neutral pH by CD spectroscopy are reversible and show ... These domains have either structurally dependent or independent Ca2+- ... that behave as a Ca2+ sensor protein, CaBP1 and.

  14. Structure and properties of electron-doped Ca1-xSmxMnO3 nanoparticles

    International Nuclear Information System (INIS)

    Sanmathi, C.S.; Retoux, R.; Singh, M.P.; Noudem, J.

    2009-01-01

    In this paper, we report the structural and magnetic properties of electron-doped Ca 1-x Sm x MnO 3 (CSM) nanoparticles. The samarium's composition 'x' was varied from 0 to 0.2 with the special attention up to 0.05. Spherical 60-70 nm polycrystalline CSM nanoparticles were synthesised by chemical co-precipitation technique. Doping of Sm 3+ in antiferromagnetic CaMnO 3 has drastically altered its magnetic behavior due to the formation of ferromagnetic clusters. For example, the CSM powder with x = 0.04 displays about 115 K magnetic Curie temperature and about 0.1 emu/mole saturation magnetization. Physical properties of our nano-CSM powders are also compared with identical bulk-samples. To understand the differences, we invoked the intra-grain and inter-grain magnetic coupling process that facilitates to enhance their ferromagnetic behaviors. Unlike the bulk samples, such magnetic couplings in nanoparticles are favored by the presence of low-level crystal and interfacial defects

  15. Perovskite-related Ca(Nb,Ti)O3.33

    International Nuclear Information System (INIS)

    Guevarra, J.; Smaalen, S. van; Daniels, P.; Rotiroti, N.; Lichtenberg, F.

    2005-01-01

    Crystals of nominal composition Ca(Nb 0.8 Ti 0.2 )O 3.4 , an n = 5 member of the homologous series A n B n O 3n+2 , have been synthesized by floating-zone melting. The material was found to be multiphase consisting also of the n = 6 type. A good single crystal of this n = 6 type was found and the crystal structure at room temperature was determined by X-ray diffraction using synchrotron radiation. Structure refinements indicate a composition of Ca(Nb 0.76 Ti 0.24 )O 3.33 . The crystal structure is monoclinic P2 1 and consists of slabs of corner-sharing (Nb,Ti)O 6 octahedra interrupted by layers of oxygen atoms. Ca atoms within the slabs are 12-fold coordinated whereas those at the borders show irregular coordination geometries. The octahedral distortion is greatest near the borders of the slabs and least near the middle of the slabs. Ti 4+ preferentially occupy octahedral sites in the middle of slabs. The non-stoichiometry in the refined composition and the insulating character of the material may be explained in terms of extra oxygen, vacancies on the cation sites, or by localization of the electrons in the 4d orbitals of Nb at the borders of slabs. (orig.)

  16. Decay of 1, 2 and 3-phonon states in 40Ca

    International Nuclear Information System (INIS)

    Fallot, M.; Scarpaci, J.A.; Frascaria, N.; Blumenfeld, Y.; Chbihi, A.; Chomaz, Ph.; Desesquelles, P.; Frankland, J.; Khan, E.; Laville, J.L.; Plagnol, E.; Pollacco, E.C.; Roussel-Chomaz, P.; Roynette, J.C.; Shrivastava, A.; Zerguerras, T.

    2007-01-01

    Inelastic scattering of 40 Ca on 40 Ca at 50 A.MeV has been measured in coincidence with protons at the GANIL facility using a very performant set-up. The SPEG spectrometer was associated with 240 CsI(Tl) scintillators of the INDRA 4π array, allowing for the measurement of complete decay events. The missing energy method was applied to these events to study the particle decay of collective states. For events with excitation energy between 42 and 55 MeV, a direct decay branch by three protons towards the low energy states of 37 Cl gives the first evidence for a 3-phonon giant resonance state. A significant direct decay branch by alpha-particles of the GQR is also measured for the first time

  17. Giant magnetoresistance on low field in non-stoichiometric La2/3Ca1/3Mn1-xO3

    International Nuclear Information System (INIS)

    Zhao Lifeng; Chen Wei; Shang Jingling; Chen Lei; Liu Sheng; Xia Zhengcai; Yuan Songliu

    2005-01-01

    Electrical transport and low field magnetoresistance (MR) are reported in the La 2/3 Ca 1/3 Mn 1-x O 3 (x = 0-0.16) samples, which are prepared by the sol-gel method followed by a sintering treatment at 1100 0 C. Experimental results show, for x = 0.06, an MR platform is observed in a temperature ∼200 K under the magnetic field of 0.5 T. With an increase in x, the MR effect gets augmented. For the sample with x = 0.16, its MR peak is as high as 50%

  18. Studies of highly ionized atoms using internal conversion: 197Au, 57Fe; electric monopole transitions in 40Ca, 42Ca, and 44Ca

    International Nuclear Information System (INIS)

    Ulrickson, M.A.

    1975-01-01

    By using heavy-ion reactions, highly ionized electronic states of atoms may be produced. The interaction between excited nuclear levels and the surrounding atomic electrons via internal conversion allows the nucleus to be used as a probe of the electronic structure of the highly ionized atoms. Studies of such atoms were undertaken for strongly internally converted nuclear levels in 197 Au and 57 Fe. The nuclear levels were Coulomb excited by using 16 O and 32 S beams. Simultaneous measurement of the lifetime of the 77-keV state of 197 Au in both neutral gold atoms and gold atoms with mean charge +10 resulted in a measured change in the internal conversion coefficient of Δalpha/alpha equals - 1.7 +- 3.0)10 -3 . This result is consistent with calculations using a Hartree-Fock--Slater program. Measurements of the electric monopole strengths for 0 + → 0 + transitions were undertaken to determine the amount of core-deformation in calcium nuclei. The E0 strengths for the decays of the 0 + states at 5.21 MeV in 40 C, 1.84 MeV in 42 Ca, and 1.88 MeV in 44 Ca were observed. The branching ratios for the subsequent E0 pair decays were measured by observing the coincident annihilation radiation from the e + member of the pair in coincidence with protons feeding the state in the cases of 42 Ca and 44 Ca, and by observing the actual coincident e + --e - pair together with protons feeding the state in the case of 40 Ca. The resulting E0 strengths (rho less than or equal to 0.06, rho = 0.34 +- 0.03, rho = 0.30 +- 0.10 for 40 Ca, 42 Ca, and 44 Ca respectively) agree with theoretical descriptions

  19. The humic matter as natural inhibitor of CaCO{sub 3} in cooling water system; Las sustancias humicas como inhibidores naturales del CaCO{sub 3}, en sistemas de enfriamiento

    Energy Technology Data Exchange (ETDEWEB)

    Celada Murillo, Ana Teresa [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2000-07-01

    Important problems are presented in cooling water systems by the formation of mineral deposits on the heat transference equipment. Calcium carbonate (CaCO{sub 3}) is one of the minerals that more deposits produces. The CaCO{sub 3} scale is controlled by the addition of sulfuric acid and chemical inhibitors with phosphates (among the most utilized). These chemicals bring an environmental impact because they are associate with eutrophication of water bodies. In order to contribute to the decrease of the use of these chemical additives, this investigation proposes the utilization of humic matter as natural inhibitor of CaCO{sub 3}, precipitation. Humic matter is a complex organic molecule present in water-and soils by the degradation of plants and animals dead. Humic matter participates in ionic interchange complex and adsorption reactions with metallic ions. Inhibition of CaCO{sub 3} precipitation was observed in synthetic and naturals water solutions (well water, river water and treated wastewater). These solutions contained typical concentrations of calcium and alkalinity of makeup and circulation water of cooling systems in electrical power plants in Mexico. The CaCO{sub 3} precipitation in these solutions was induced by the addition of NaOH 0.1 N in continuos form (pH critical method), in absence and presence of humic matter. Time and NaOH volume were registered. Increase of CaCO{sub 3} nucleation time was evident in presence of humic matter. In the synthetic solutions, the nucleation time was increased 30-40%; while in the natural watery solutions (well water) the humic inhibited the CaCO{sub 3} precipitation during 120 minutes of experimentation. [Spanish] En la instalacion de sistemas solares para enfriamiento que emplean agua se presentan problemas importantes por la formacion de depositos minerales sobre equipos de transferencia de calor. El carbonato de calcio (CaCO{sub 3}) es uno de los minerales que mas depositos produce. Con el fin de disminuir su

  20. Clinical applicability of determination of serum tumor markers (CEA, CA15-3 and CA125) levels changes for assessment of efficacy of chemotherapy in patients with breast cancer

    International Nuclear Information System (INIS)

    Xu Junying; Liu Chaoying; Li Jiang; Hu Hong; Wang Runjie

    2009-01-01

    Objective: To study the usefulness of monitoring changes of serum levels of tumor markers (CEA, CA15-3 and CA125) for assessment of efficacy of chemotherapy in patients with breast cancer. Methods: Serum CEA, CA15-3 and CA125 levels were measured with CLIA three days before beginning 1st course of appropriate chemotherapy and 3 weeks after completing 2nd course of treatment in 45 patients with advanced breast cancer (TNM stage III, n=20, stage IV n=25). Results: Expressed as CR, PR, SD and PD as defined by the changes of serum tumor markers levels (according to Bac D.J. et al) were compared with clinically observed ones (WHO standard). The serum levels of Cea, CA15-3 decreased markedly in the CR and PR groups of patients but increased markedly in PD patients (P 0.05). The coincidence rate between the results observed clinically and results derived from tumor marker changes was 50.0% for CEA, 55.6% for CA15-3, 31.1% for CA125 and 73% for three markers combined. Conclusion: Combined determination of the changes of serum levels of three tumor marker would help to make a reasonably satisfactory assessment of efficacy of chemotherapy in patients with breast cancer. (authors)

  1. Characteristics of the binding of [3H]nitrendipine to rabbit ventricular membranes: modification by other Ca++ channel antagonists and by the Ca++ channel agonist Bay K 8644

    International Nuclear Information System (INIS)

    Janis, R.A.; Sarmiento, J.G.; Maurer, S.C.; Bolger, G.T.; Triggle, D.J.

    1984-01-01

    This study was carried out to characterize [ 3 H]nitrendipine binding to cardiac membranes and to test the hypothesis that high affinity binding of Ca++ channel antagonists and agonists is to Ca++ channels. Binding was specific, rapid, reversible and stereoselective. The relative order of potency of nifedipine analogs for inhibition of binding was the same as that for inhibition of smooth and cardiac muscle contraction. Results with diltiazem, verapamil and lidoflazine were consistent with the hypothesis that nondihydropyridine Ca++ channel antagonists act at one or more sites allosterically linked to the 1,4-dihydropyridine site in cardiac cells. The Ca++ channel agonist Bay K 8644 [methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate] displaced specifically bound [ 3 H]nitrendipine in an apparently competitive manner with an IC50 value of 5 nM. The results suggest that organic antagonists do not act by physically blocking the Ca++ channel. The data also support the hypothesis that the high affinity binding sites for [ 3 H]nitrendipine in isolated cardiac membranes are associated with Ca++ channels that are inactivated or are otherwise unavailable for opening

  2. Dihydrotestosterone induces SREBP-1 expression and lipogenesis through the phosphoinositide 3-kinase/Akt pathway in HaCaT cells

    Directory of Open Access Journals (Sweden)

    Zhou Bing-rong

    2012-11-01

    Full Text Available Abstract Background The purpose of this study was to investigate the effects and mechanisms of dihydrotestosterone (DHT-induced expression of sterol regulatory element binding protein-1 (SREBP-1, and the synthesis and secretion of lipids, in HaCaT cells. HaCaT cells were treated with DHT and either the phosphoinositide 3-kinase inhibitor LY294002 or the extracellular-signal-regulated kinase (ERK inhibitor PD98059. Real time-PCR, Western blot, Oil Red staining and flow cytometry were employed to examine the mRNA and protein expressions of SREBP-1, the gene transcription of lipid synthesis, and lipid secretion in HaCaT cells. Findings We found that DHT upregulated mRNA and protein expressions of SREBP-1. DHT also significantly upregulated the transcription of lipid synthesis-related genes and increased lipid secretion, which can be inhibited by the addition of LY294002. Conclusions Collectively, these results indicate that DHT induces SREBP-1 expression and lipogenesis in HaCaT cells via activation of the phosphoinositide 3-kinase/Akt Pathway.

  3. Development of novel antibacterial active, HaCaT biocompatible and biodegradable CA-g-P(3HB-EC biocomposites with caffeic acid as a functional entity

    Directory of Open Access Journals (Sweden)

    H. M. N. Iqbal

    2015-09-01

    Full Text Available We have developed novel composites by grafting caffeic acid (CA onto the P(3HB-EC based material and laccase from Trametes versicolor was used for grafting purposes. The resulting composites were designated as CA-g-P(3HB-EC i.e., P(3HB-EC (control, 5CA-g-P(3HB-EC, 10CA-g-P(3HB-EC, 15CA-g-P(3HB-EC and 20CA-g-P(3HB-EC. FT-IR (Fourier-transform infrared spectroscopy was used to examine the functional and elemental groups of the control and laccase-assisted graft composites. Evidently, 15CA-g-P(3HB-EC composite exhibited resilient antibacterial activity against Gram-positive and Gram-negative bacterial strains. Moreover, a significant level of biocompatibility and biodegradability of the CA-g-P(3HB-EC composites was also achieved with the human keratinocytes-like HaCaT cells and soil burial evaluation, respectively. In conclusion, the newly developed novel composites with multi characteristics could well represent the new wave of biomaterials for medical applications, and more specifically have promising future in the infection free would dressings, burn and/or skin regeneration field due to their sophisticated characteristics.

  4. Teratological studies of DTPA-CaNa3, DTPA-ZnNa3 and quinamic acid in mice

    International Nuclear Information System (INIS)

    Luo Meichu; Ruan Tianming; Tong Shungao

    1989-01-01

    DTPA-CaNa 3 , DTPA-ZnNa 3 and quinamic acid are effective chelating agents for removing actinide elements from the body. In this experiment, different doses of DTPA-CaNa 3 , DTPA-ZnNa 3 and quinamic acid were given to mice on gestation days 6-10. Eight groups of mice received 0.8 and 2.0 mM/kg of DTPA-CaNa 3 , 3.8, 7.6, and 11.4 mM/kg of DTPA-ZnNa 3 and 0.42, 2.1, and 4.2 mM/kg of quinamic acid. Hypetonic saline and isotonic saline were given to two control groups. DTPA-CaNa 3 and quinamidic acid were found to be much more toxic to fetus of mice than DTPA-ZnNa 3 . When the doses of DTPA-CaMa 3 and quinamidic acid were 20 times higher than the human dose, the number of resorbed fetus was increased and the number and weight of live fetus were reduced. The result of injection with 7.6 mM/kg (200 times of human dose)DTPA-ZnNa 3 and that of injection with isotonic saline are the same. Therefore, we suggest that the DTPA-CaNa 3 and quinamidic acid should not be given to pregnant woman, if chelation therapy is needed, while the much safer DTPA-ZnNa 3 could be used

  5. Determination of 40Ca and 48Ca matter densities by 600 MeV and 1 GeV proton elastic scattering

    International Nuclear Information System (INIS)

    Brissaud, I.; Campi, X.

    1979-02-01

    The 600MeV and 1GeV data of proton elastic scattering on 40 Ca and 48 Ca have been analyzed in the framework of the Glauber model. The matter distributions are extracted from the data in an approximately model-independent form based on a Fourier series expansion. A similar method is used to deduce directly the 48 Ca- 40 Ca neutron density difference

  6. Assessing PIK3CA and PTEN in Early-Phase Trials with PI3K/AKT/mTOR Inhibitors

    Directory of Open Access Journals (Sweden)

    Filip Janku

    2014-01-01

    Full Text Available Despite a wealth of preclinical studies, it is unclear whether PIK3CA or phosphatase and tensin homolog (PTEN gene aberrations are actionable in the clinical setting. Of 1,656 patients with advanced, refractory cancers tested for PIK3CA or PTEN abnormalities, PIK3CA mutations were found in 9% (146/1,589, and PTEN loss and/or mutation was found in 13% (149/1,157. In multicovariable analysis, treatment with a phosphatidylinositol 3-kinase (PI3K/AKT/mammalian target of rapamycin (mTOR inhibitor was the only independent factor predicting response to therapy in individuals harboring a PIK3CA or PTEN aberration. The rate of stable disease ≥6 months/partial response reached 45% in a subgroup of individuals with H1047R PIK3CA mutations. Aberrations in the PI3K/AKT/mTOR pathway are common and potentially actionable in patients with diverse advanced cancers. This work provides further important clinical validation for continued and accelerated use of biomarker-driven trials incorporating rational drug combinations.

  7. Synthesis and luminescence enhancement of CaTiO{sub 3}:Bi{sup 3+} yellow phosphor by codoping Al{sup 3+}/B{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Renping, E-mail: jxcrp@163.com; Fu, Ting; Xu, Haidong; Luo, Wenjie; Peng, Dedong; Chen, Zhiquan; Fu, Jingwei

    2016-07-25

    CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors are synthesized by solid-state reaction method in air. With excitation 272 and 320 nm, broad PL band peaking at 555 nm with full width at half maximum ∼200 nm is observed in the range of 400–800 nm due to the {sup 3}P{sub 1,0} → {sup 1}S{sub 0} transitions of Bi{sup 3+} ion. PLE spectrum monitored at 555 nm contains two PLE band peaking at ∼272 and 320 nm within the range 230–420 nm owing to metal-to-metal charge-transfer and {sup 1}S{sub 0} → {sup 3}P{sub 1} transition of Bi{sup 3+} ion, respectively. The optimal Bi{sup 3+} doping concentration in CaTiO{sub 3}:Bi{sup 3+} phosphor is about 0.5 mol%. Luminescence properties of CaTiO{sub 3}:Bi{sup 3+} phosphor may be improved obviously by co-doping Al{sup 3+}/B{sup 3+} ions, and its emission intensity can be enhanced 13–15 times after Al{sup 3+} ion is co-doped. Luminous mechanism of CaTiO{sub 3}:Bi{sup 3+} phosphor is analyzed by energy level diagram of Bi{sup 3+} ion. Decay curve and time-resolved spectra confirm that only a single type of Bi{sup 3+} luminescence center exists in CaTiO{sub 3}:Bi{sup 3+} phosphor. - Graphical abstract: PL spectra of CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors and the corresponding pictures under 365 nm UV lamp. - Highlights: • CaTiO{sub 3}:Bi{sup 3+} and CaTiO{sub 3}:Bi{sup 3+}, Al{sup 3+}/B{sup 3+} phosphors are synthesized by solid-state reaction in air. • Broadband emission with FWHM ∼200 nm is observed within the range 400–800 nm. • Luminescence properties of CaTiO{sub 3}:Bi{sup 3+} phosphor can be improved by codoping Al{sup 3+}/B{sup 3+} ions. • PL intensity of CaTiO{sub 3}:Bi{sup 3+} phosphor can be enhanced 13–15 times after Al{sup 3+} ion is codoped.

  8. Late calcium EDTA rescues hippocampal CA1 neurons from global ischemia-induced death.

    Science.gov (United States)

    Calderone, Agata; Jover, Teresa; Mashiko, Toshihiro; Noh, Kyung-min; Tanaka, Hidenobu; Bennett, Michael V L; Zukin, R Suzanne

    2004-11-03

    Transient global ischemia induces a delayed rise in intracellular Zn2+, which may be mediated via glutamate receptor 2 (GluR2)-lacking AMPA receptors (AMPARs), and selective, delayed death of hippocampal CA1 neurons. The molecular mechanisms underlying Zn2+ toxicity in vivo are not well delineated. Here we show the striking finding that intraventricular injection of the high-affinity Zn2+ chelator calcium EDTA (CaEDTA) at 30 min before ischemia (early CaEDTA) or at 48-60 hr (late CaEDTA), but not 3-6 hr, after ischemia, afforded robust protection of CA1 neurons in approximately 50% (late CaEDTA) to 75% (early CaEDTA) of animals. We also show that Zn2+ acts via temporally distinct mechanisms to promote neuronal death. Early CaEDTA attenuated ischemia-induced GluR2 mRNA and protein downregulation (and, by inference, formation of Zn2+-permeable AMPARs), the delayed rise in Zn2+, and neuronal death. These findings suggest that Zn2+ acts at step(s) upstream from GluR2 gene downregulation and implicate Zn2+ in transcriptional regulation and/or GluR2 mRNA stability. Early CaEDTA also blocked mitochondrial release of cytochrome c and Smac/DIABLO (second mitochondria-derived activator of caspases/direct inhibitor of apoptosis protein-binding protein with low pI), caspase-3 activity (but not procaspase-3 cleavage), p75NTR induction, and DNA fragmentation. These findings indicate that CaEDTA preserves the functional integrity of the mitochondrial outer membrane and arrests the caspase death cascade. Late injection of CaEDTA at a time when GluR2 is downregulated and caspase is activated inhibited the delayed rise in Zn2+, p75NTR induction, DNA fragmentation, and cell death. The finding of neuroprotection by late CaEDTA administration has striking implications for intervention in the delayed neuronal death associated with global ischemia.

  9. Effect of carbonation temperature on CO{sub 2} adsorption capacity of CaO derived from micro/nanostructured aragonite CaCO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Hlaing, Nwe Ni, E-mail: nwenihlaing76@gmail.com [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Sreekantan, Srimala, E-mail: srimala@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Hinode, Hirofumi, E-mail: hinode@ide.titech.ac.jp; Kurniawan, Winarto, E-mail: Kurniawan.w.ab@m.titech.ac.jp [Department of International Development Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo (Japan); Thant, Aye Aye, E-mail: a2thant@gmail.com [Department of Physics, University of Yangon, 11041 Kamayut, Yangon (Myanmar); Othman, Radzali, E-mail: radzali@utem.edu.my [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Malacca (Malaysia); Mohamed, Abdul Rahman, E-mail: chrahman@eng.usm.my [Low Carbon Economy (LCE) Research Group, School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia); Salime, Chris, E-mail: chris.salim@surya.ac.id [Environmental Engineering, Surya University, Tangerang, 15810 Banten (Indonesia)

    2016-07-06

    Recent years, CaO-based synthetic materials have been attracted attention as potential adsorbents for CO{sub 2} capture mainly due to their high CO{sub 2} adsorption capacity. In this study, micro/nanostructured aragonite CaCO{sub 3} was synthesized by a simple hydrothermal method with using polyacrylamide (PAM). The structural, morphological and thermal properties of the synthesized sample were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and thermogravimetry analysis (TG-DTA). The XRD and FESEM results showed that the obtained sample was aragonite CaCO{sub 3} with aggregated nanorods and microspheres composed of nanorods. A TG-DTA apparatus with Thermoplus 2 software was used to investigate the effect of carbonation temperature on the CO{sub 2} adsorption capacity of CaO derived from aragonite CaCO{sub 3} sample. At 300 °C, the sample reached the CO{sub 2} adsorption capacity of 0.098 g-CO{sub 2}/g-adsorbent, whereas the sample achieved the highest capacity of 0.682 g-CO{sub 2}/g-adsorbent at 700 °C. The results showed that the carbonation temperature significantly influenced on the CO{sub 2} adsorption capacity of the CaO derived from aragonite CaCO{sub 3}.

  10. Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave dielectric ceramic

    Science.gov (United States)

    Hu, Mingzhe; Wei, Huanghe; Xiao, Lihua; Zhang, Kesheng; Hao, Yongde

    2017-10-01

    The crystal structure and dielectric properties of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the B-site order-disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li1/3Nb2/3)0.8Sn0.2]O3-δ ceramic can be compensated and the optimal microwave dielectric properties can reach 𝜀r = 25.66, Qf = 18,894 GHz and TCF = -6.3 ppm/∘C when sintered at 1170∘C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.

  11. Ca(2+-dependent regulation of the Ca(2+ concentration in the myometrium mitochondria. II. Ca(2+ effects on mitochondria membranes polarization and [Ca(2+](m

    Directory of Open Access Journals (Sweden)

    L. G. Babich

    2017-06-01

    Full Text Available It is known that Ca2+ accumulation in the mitochondria undergoes complex regulation by Ca2+ itself. But the mechanisms of such regulation are still discussed. In this paper we have shown that Ca ions directly or indirectly regulate the level of myometrium mitochondria membranes polarization. The additions of 100 µM Ca2+ were accompanied by depolarization of the mitochondria membranes. The following experiments were designed to study the impact of Ca2+ on the myometrium mitochondria [Ca2+]m. Isolated myometrium mitochondria were preincubated without or with 10 μM Са2+ followed by 100 μM Са2+ addition. Experiments were conducted in three mediums: without ATP and Mg2+ (0-medium, in the presence of 3 mM Mg2+ (Mg-medium and 3 mM Mg2+ + 3 mM ATP (Mg,ATP-medium. It was shown that the effects of 10 μM Са2+ addition were different in different mediums, namely in 0- and Mg-medium the [Ca2+]m values increased, whereas in Mg,ATP-medium statistically reliable changes were not registered. Preincubation of mitochondria with 10 μM Са2+ did not affect the [Ca2+]m value after the addition of 100 μM Са2+. The [Ca2+]m values after 100 μM Са2+ addition were the same in 0- and Mg,ATP-mediums and somewhat lower in Mg-medium. Preliminary incubation of mitochondria with 10 μM Са2+ in 0- and Mg-mediums reduced changes of Fluo 4 normalized fluorescence values that were induced by 100 μM Са2+ additions, but in Mg,ATP-medium such differences were not recorded. It is concluded that Са2+ exchange in myometrium mitochondria is regulated by the concentration of Ca ions as in the external medium, so in the matrix of mitochondria. The medium composition had a significant impact on the [Са2+]m values in the absence of exogenous cation. It is suggested that light increase of [Са2+]m before the addition of 100 μM Са2+ may have a positive effect on the functional activity of the mitochondria.

  12. Production and electrical parameters of La /SUB 1-x/ Ca /SUB x/ Cr /SUB 1-y/ Ni /SUB y/ O3 (x ranging from 0-0.3; y ranging from 0-1)

    International Nuclear Information System (INIS)

    Kononyuk, I.F.; Surmach, N.G.; Tolochko, S.P.

    1986-01-01

    This paper deals with the conditions for the formation of LaCr /SUB 1-y/ Ni /SUB y/ O 3 , La /SUB 1-x/ Ca /SUB x/ CrO 3 , and La /SUB 1-x/ Ca /SUB x/ Cr /SUB 1-y/ Ni /SUB y/ O 3 solid solutions and the electrical parameters of these. The initial materials were lanthanum, calcium, nickel, and chromium nitrates of pure or analytical grade. It is shown that partial replacement of lanthanum by calcium does not have any substantial effect on the electrical parameters of La /SUB 1-x/ Ca /SUB x/ Cr /SUB 1-y/ Ni /SUB y/ O 3 solid solutions for y = 0.2-0.6, but it increases the conductivity of La /SUB 1-x/ Ca /SUB x/ CrO 3 by three orders of magnitude as x varies from 0 to 0.3. The electrical parameters are virtually the same for lanthanum chromites containing calcium and strontium. The solubility of calcium in lanthanum chromite is reduced in the presence of nickel

  13. Value and significance of tumor markers as CEA, CA125, SCC-Ag, CA199 and CYFRA21-1 in the diagnosis of cervical cancer

    Directory of Open Access Journals (Sweden)

    Xiao-Juan Wang

    2017-09-01

    Full Text Available Objective: To investigate the value and significance of serum CEA, CA125, SCC-Ag, CA199 and CYFRA21-1 in the diagnosis of cervical cancer by comparing the detection of five serum markers. Methods: A total of 108 cases were divided into three groups, including 60 cervical cancerpatients and 20 cervical intraepithelial neoplasiain patients treated in our hospital from September 2015 to September 2016 and 28 healthy women. Radioimmunoassay was used to detect and compare the serum levels of CA125, CA199, CYFRA21-1 and ELISA method was used to detect and compare the serum levels of SCC-Ag, CEA. Results: (1 There was no statistically significant difference in the serum CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels between CIN group and control group. The serums CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels of cervical cancer patients were significantly higher than the other two groups. The differences were statistically significant. (2There were statistically significant differences in the serum CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels between different cervical pathological type groups.The serum CA125, CA199, CEA levels of cervical glandular cancer patients were significantly higher than the other two groups. The differences were statistically significant. The serum SCC-Ag, CYFRA21-1 levels of cervical squamous cancer patients were significantly higher than the other two groups. The differences were statistically significant. Conclusion: The serums CEA, CA125, SCC-Ag, CA199, CYFRA21-1 levels of cervical cancer patients were significantly higher than cervical intraepithelial neoplasiain patients and healthy women. The serum CA125, CA199, CEA levels of cervical glandular cancer patients were significantly higher and the serum SCC-Ag, CYFRA21-1 levels of cervical squamous cancer patients were significantly higher. The five tumor markers can be used in diagnosis of cervical cancer and they are also worthy in distinguishing cervical pathological types.

  14. Novel electrical conductivity properties in Ca-doped BiFeO3 nanoparticles

    International Nuclear Information System (INIS)

    Wang, X.; Wang, S. Y.; Liu, W. F.; Xi, X. J.; Zhang, H.; Guo, F.; Xu, X. L.; Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B.

    2015-01-01

    The charge defective structure in Bi 1−x Ca x FeO 3 (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum

  15. A Devil in the Details: Matrix-Dependent 40Ca42Ca++/42Ca+ and Its Effects on Estimates of the Initial 41Ca/40Ca in the Solar System

    Science.gov (United States)

    McKeegan, K. D.; Liu, M.-C.

    2015-07-01

    Ian Hutcheon established that the molecular ion interference 40Ca42Ca++/42Ca+ on 41K+ is strongly dependent on the mineral analyzed. Correction for this "matrix effect" led to a downward revision of the initial 41Ca/40Ca of the solar system.

  16. Effect of ball-milling to the surface morphology of CaCO3

    Science.gov (United States)

    Sulimai, N. H.; Rani, Rozina Abdul; Khusaimi, Z.; Abdullah, S.; Salifairus, M. J.; Alrokayan, Salman; Khan, Haseeb; Rusop, M.

    2018-05-01

    Calcium Carbonate can be synthesized in many approaches. This work studied on the physical changes to Calcium Carbonate (CaCO3) by ball-milling activity in different parameters; number of ball; collision duration; revolution per minute (RPM). Zirconia balls were used in the work because it has the best durability to withstand ball-milling conditions set. Industrial grade CaCO3 particles that were run in aforementioned parameters were characterized by Field Emission Scanning Electron Microscope (FE-SEM) to study the physical changes on the size and surface of the CaCO3. They were also characterized with Fourier Transform Infra-red Spectroscopy (FTIR) were fingerprint of CaCO3 regions were identified and any changes in the band position and intensity were discussed. Number of Zirconia balls and collision duration is directly proportional to the absorbance intensity whereas it is inversely proportional for the rpm. The best number of parameters producing the highest Absorbance is 100 Zirconia balls in duration of 1 hour and 100rpm.

  17. Glu¹⁰⁶ in the Orai1 pore contributes to fast Ca²⁺-dependent inactivation and pH dependence of Ca²⁺ release-activated Ca²⁺ (CRAC) current.

    Science.gov (United States)

    Scrimgeour, Nathan R; Wilson, David P; Rychkov, Grigori Y

    2012-01-15

    FCDI (fast Ca²⁺-dependent inactivation) is a mechanism that limits Ca²⁺ entry through Ca²⁺ channels, including CRAC (Ca²⁺ release-activated Ca²⁺) channels. This phenomenon occurs when the Ca²⁺ concentration rises beyond a certain level in the vicinity of the intracellular mouth of the channel pore. In CRAC channels, several regions of the pore-forming protein Orai1, and STIM1 (stromal interaction molecule 1), the sarcoplasmic/endoplasmic reticulum Ca²⁺ sensor that communicates the Ca²⁺ load of the intracellular stores to Orai1, have been shown to regulate fast Ca²⁺-dependent inactivation. Although significant advances in unravelling the mechanisms of CRAC channel gating have occurred, the mechanisms regulating fast Ca²⁺-dependent inactivation in this channel are not well understood. We have identified that a pore mutation, E106D Orai1, changes the kinetics and voltage dependence of the ICRAC (CRAC current), and the selectivity of the Ca²⁺-binding site that regulates fast Ca²⁺-dependent inactivation, whereas the V102I and E190Q mutants when expressed at appropriate ratios with STIM1 have fast Ca²⁺-dependent inactivation similar to that of WT (wild-type) Orai1. Unexpectedly, the E106D mutation also changes the pH dependence of ICRAC. Unlike WT ICRAC, E106D-mediated current is not inhibited at low pH, but instead the block of Na⁺ permeation through the E106D Orai1 pore by Ca²⁺ is diminished. These results suggest that Glu¹⁰⁶ inside the CRAC channel pore is involved in co-ordinating the Ca²⁺-binding site that mediates fast Ca²⁺-dependent inactivation.

  18. Linear optical properties of Ca4EuO(BO3)3 and Eu3+ : Ca4GdO(BO3)3 crystals

    International Nuclear Information System (INIS)

    Antic-Fidancev, E.; Lemaitre-Blaise, M.; Porcher, P.; Caramanian, A.; Aka, G.

    1998-01-01

    Full text: The title compounds are now intensively studied due to their quadratic nonlinear properties in view of applications, e.g. high power laser frequency conversion. Rare earth calcium oxoborates, Ca 4 REO(BO 3 ) 3 , constitute an isostructural family along the rare earth series with RE = La - Lu, Y included. These compounds crystallize in the monoclinic biaxial crystal system with Cm (N 8) space group. They are isostructural to the calcium fluoroborate Ca 5 (BO 3 ) 3 F which is related to the fluoroapatite structure Ca 5 (PO 4 ) 3 F. The rare earth ions are located in the distorted octahedron with C s point site symmetry in the mirror plane. Two types of distorted octahedral sites exist for calcium ions. The existence of some disorder between calcium and rare earth atoms is suspected from the structural analysis. Good optical quality crystals of europium (or gadolinium) oxoborate, EuCOB (GdCOB) have been grown from the stoichiometric melt by the Czochralski pulling method. From the luminescence of the Eu 3+ doped gadolinium or in the europium stoichiometric compound very complex emission spectra have been obtained. It principally depends on the preparation method of studied samples: i) for a monocrystalline sample, a single phase with a single site is observed; ii) for a polycrystalline sample complex feature occurs. It is probably due to an expanded disorder between calcium and rare earth atoms. Practically, there is one principal site corresponding to the low symmetry site of the rare earth as expected from the structural investigation. Other minor sites are attributed to the local distortion created around the active rare earth ion. The intensity of the emission lines of Eu 3+ used as a local structural probe related to these minor sites increases when the gadolinium in Ca 4 GdO(BO 0 ) 3 is substituted by lanthanum or yttrium ions. It seems therefore evident that the synthesis of these rare earth calcium oxoborates must be realised carefully. The crystal

  19. Spin glass properties of Y0.7Ca0.3MnO3 and Th0.35Ba0.37Ca0.28MnO3

    Science.gov (United States)

    Sedmidubský, D.; Hejtmánek, J.; Maryško, M.; Jirák, Z.; Hardy, V.; Martin, C.

    2002-05-01

    Two perovskite manganites with the same nominal concentration of Mn4+ have been studied by the magnetic susceptibility and specific heat measurements: the Y0.7Ca0.3MnO3 single crystal (YCa) with low tolerance factor and negligible ionic radii variance and the Th0.35Ba0.37Ca0.28MnO3 (ThBaCa) ceramics with favorable tolerance factor but huge substitution induced disorder. Both systems were found to possess an insulating ground state with activated conductivity. The ac susceptibility data exhibit a frequency dependent peak at Tsg=32 K for YCa and Tsg=43 K for ThBaCa. The Cole-Cole analysis revealed a sharper than exponential increase of the relaxation time for the former sample while almost linear slowly growing characteristics below Tsg were observed for the latter one. Using the heat capacity curves, the magnetic contribution was separated and magnetic peaks with typical linear on-set tails were obtained. This observation and the abovementioned characteristics are all indicative of spin or cluster glass character. The necessary magnetic frustration is here induced by a considerable tilting of MnO6 octahedra and deformation of Mn-O bonds which occur in a cooperative manner for YCa and locally for ThBaCa.

  20. [Endoplasmic-mitochondrial Ca(2+)-functional unit: dependence of respiration of secretory cells on activity of ryanodine- and IP3 - sensitive Ca(2+)-channels].

    Science.gov (United States)

    Velykopols'ka, O Iu; Man'ko, B O; Man'ko, V V

    2012-01-01

    Using Clark oxygen electrode, dependence of mitochondrial functions on Ca(2+)-release channels activity of Chironomus plumosus L. larvae salivary glands suspension was investigated. Cells were ATP-permeabilized in order to enable penetration of exogenous oxidative substrates. Activation of plasmalemmal P2X-receptors (as well as P2Y-receptors) per se does not modify the endogenous respiration of salivary gland suspension. That is, Ca(2+)-influx from extracellular medium does not influence functional activity of mitochondria, although they are located along the basal part of the plasma membrane. Activation of RyRs intensifies endogenous respiration and pyruvate-malate-stimulated respiration, but not succinate-stimulated respiration. Neither activation of IP3Rs (via P2Y-receptors activation), nor their inhibition alters endogenous respiration. Nevertheless, IP3Rs inhibition by 2-APB intensifies succinate-stimulated respiration. All abovementioned facts testify that Ca2+, released from stores via channels, alters functional activity of mitochondria, and undoubtedly confirm the existence of endoplasmic-mitochondrial Ca(2+)-functional unit in Ch. plumosus larvae salivary glands secretory cells. In steady state of endoplasmic-mitochondrial Ca(2+)-functional unit the spontaneous activity of IP3Rs is observed; released through IP3Rs, Ca2+ is accumulated in mitochondria via uniporter and modulates oxidative processes. Activation of RyRs induces the transition of endoplasmic-mitochondrial Ca(2+)-functional unit to the active state, which is required to intensify cell respiration and oxidative phosphorylation. As expected, the transition of endoplasmic-mitochondrial Ca(2+)-functional unit to inactivated state (i. e. inhibition of Ca(2+)-release channels at excessive [Ca2+]i) limits the duration of signal transduction, has protective nature and prevents apoptosis.

  1. Synthesis of carbon-11 labeled 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinolinium derivatives as new potential PET SK{sub Ca} channel imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Gao Mingzhang; Wang Min [Department of Radiology, Indiana University School of Medicine, 1345 West 16th Street, L-3 Room 202, Indianapolis, IN 46202 (United States); Zheng Qihuang [Department of Radiology, Indiana University School of Medicine, 1345 West 16th Street, L-3 Room 202, Indianapolis, IN 46202 (United States)], E-mail: qzheng@iupui.edu

    2008-02-15

    Small conductance Ca{sup 2+}-activated K{sup +} (SK{sub Ca}) channels play an important role in many functions such as neuronal communication and behavioral plasticity, secretion, and cell proliferation. SK{sub Ca} channel modulation is associated with various brain, heart, and cancer diseases. N-methyl-laudanosine and its structurally related derivatives, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums, are reversible and selective SK{sub Ca} channel blockers. Carbon-11 labeled N-methyl-laudanosine and its tetrahydroisoquinolinium derivatives may serve as new probes for positron emission tomography (PET) to image SK{sub Ca} channels in the brain, heart, and cancer. The key intermediates, substituted isoquinolines (3a-c), were synthesized using a modification of the Pomeranz-Fritsch procedure. The precursors, substituted 1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3,4-tetrahydroisoquinolines (8a-c), and their corresponding reference standards, substituted 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums (9a-c), were synthesized from compounds 3a-c with 3,4-dimethoxybenzyl chloride (2) in multiple steps with moderate to excellent chemical yields. The precursor 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-2-methyl-1,2,3, 4-tetrahydroisoquinoline (10) was commercially available, and the methylation of compound 10 with methyl iodide provided N-methyl-laudanosine (11). The target quaternary ammonium tracers, carbon-11 labeled 1-(3,4-dimethoxybenzyl)-2,2-dimethyl-1,2,3,4-tetrahydroisoquinoliniums ([{sup 11}C]9a-c and [{sup 11}C]11), were prepared by N-[{sup 11}C]methylation of the tertiary amine precursors (8a-c and 10) with [{sup 11}C]methyl triflate and isolated by a simplified solid-phase extraction (SPE) purification using a SiO{sub 2} or cation-exchange CM Sep-Pak cartridge in 40-65% radiochemical yields.

  2. Compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O on the strength of steel slag: cement binding materials

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Liqian; Liu, Jiaxiang; Liu, Qian, E-mail: ljxpost@263.net [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, The State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing (China)

    2016-03-15

    In this study, we replaced 30% of the cement with steel slag to prepare binding material; additionally, small amounts of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were added. This was done to study the compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O on the strength of steel slag-cement binding materials. The hydration degree of the steel slag cementitious material was analyzed by XRD, TG and SEM. The results showed that the optimum proportions of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O were 3% and 2%, respectively. Compared with the steel slag-cement binders without adding CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O, the compressive strength increased by 59.9% at 3 days and by 17.8% at 28 days. Acting as the nucleation matrix, CaCO{sub 3} could accelerate the hydration of C{sub 3}S. In addition, CaCO{sub 3} was involved in the hydration reaction, generating a new hydration product, which could stably exist in a slurry. Meanwhile, CaSO{sub 4}·2H{sub 2}O could increase the number of AFt. The compound effect of CaCO{sub 3} and CaSO{sub 4}·2H{sub 2}O enhanced the intensity of steel slag-cement binding materials and improved the whole hydration behavior. (author)

  3. Formation pathways in the synthesis and properties of (Tl0.5Pb0.5)(Sr0.9Ba0.1)2Ca2Cu3Oz and (Tl0.5Pb0.5)(Sr0.8Ba0.2)2Ca2Cu3Oz-1223 superconductors

    International Nuclear Information System (INIS)

    Auinger, M; Gritzner, G; Bertrand, Ch; Galez, Ph; Soubeyroux, J-L

    2007-01-01

    The formation pathway of (Tl 0.5 Pb 0.5 )(Sr 0.9 Ba 0.1 ) 2 Ca 2 Cu 3 O z and (Tl 0.5 Pb 0.5 )(Sr 0.8 Ba 0.2 ) 2 Ca 2 Cu 3 O z was studied by neutron and x-ray diffraction. The following reaction pathway was proposed: thallium oxide and lead oxide react with Sr-rich (Sr 1-x Ca x )CuO 2 and Ca-rich (Ca x Sr 1-x )O to form Sr 4 Tl 2 O 7 and (Ca x Sr 1-x )PbO 3 , respectively. The thallate and the plumbate compounds then form the (Tl 0.5 Pb 0.5 )-1212 phase starting at a temperature of 600 deg. C. Finally, between 850 and 900 deg. C, the 1223 phase is formed from (Tl 0.5 Pb 0.5 )-1212 (Ca x Sr 1-x ) 2 CuO 3 and CuO. Parallel experiments to fabricate the (Tl, Pb)-1223 superconductor resulted in specimens with critical temperatures of 117.5 K and 116 K, respectively, and transition widths of 2 K. Differences between the pathways for the formation of Pb-doped, Sr-rich and Pb-free, Ba-rich Tl-1223 superconductors are discussed

  4. Investigations on FCAM-III (Ca2.38Mg2.09Fe3+10.61Fe2+1.59Al9.33O36): A new homologue of the aenigmatite structure-type in the system CaO-MgO-Fe2O3-Al2O3

    Science.gov (United States)

    Zöll, Klaus; Kahlenberg, Volker; Krüger, Hannes; Tropper, Peter

    2018-02-01

    In the course of a systematic study of a part of the quaternary system Fe2O3-CaO-Al2O3-MgO (FCAM) the previously unknown compound Ca2.38Mg2.09Fe3+10.61Fe2+1.59Al9.33O36 (FCAM-III) has been synthesized. By analogy with the so-called SFCA series [1-5], our investigation in the system of FCAM shows the existence of a stoichiometric homologous series M14+6nO20+8n, where M = Fe, Ca, Al, Mg and n = 1 or 2. In air, we can prove the formation of coexisting FCAM-III and FCAM-I solid solutions at 1400 °C. By increasing the temperature up to 1425 °C FCAM-I disappears completely and FCAM-III co-exists with magnesiumferrite and a variety of calcium iron oxides. At 1450 °C FCAM-III breaks down to a mixture of FCAM-I again as well as magnesioferrite and melt. Small single-crystals of FCAM-III up to 35 μm in size could be retrieved from the 1425 °C experiment and were subsequently characterized using electron microprobe analysis and synchroton X-ray single-crystal diffraction. Finally the Fe2+/Fetot ratio was calculated from the total iron content based on the crystal-chemical formula obtained from EMPA measurements and charge balance considerations. FCAM-III or Ca2.38Mg2.09Fe3+10.61Fe2+1.59Al9.33O36 has a triclinic crystal structure (space group P 1 ̅). The basic crystallographic data are: a = 10.223(22) Å, b = 10.316(21) Å, c = 14.203(15) Å, α = 93.473(50)°, β = 107.418(67)°, γ = 109.646(60)°, V = 1323.85(2) ų, Z = 1. Using Schreinemaker's technique to analyze the phase relations in the system Fe2O3-CaO-Al2O3-MgO it was possible to obtain the semi-quantitative stability relations between the participating phases and construct a topologically correct phase sequence as a function of T and fO2. The analysis shows that Ca2Al0.5Fe1.5O5 (C2A0.25F0.75) and CaAl1.5Fe2.5O7 (CA0.75F1.25) with higher calculated Fe2+ contents are preferably formed at lower oxygen fugacity and react to CaAl0.5Fe1.5O4 (CA0.25F0.75) by increasing fO2. Spinel-type magnesium

  5. Hydrolysis of molten CaCl2-CaF2 with additions of CaO

    Directory of Open Access Journals (Sweden)

    Espen Olsen

    2017-10-01

    Full Text Available Calcium halide based molten salts have recently attracted interest for a number of applications such as direct reduction of oxides for metal production and as liquefying agent in cyclic sorption processes for CO2 by CaO from dilute flue gases (Ca-looping. A fundamental aspect of these melts is the possible hydrolysis reaction upon exposure to gaseous H2O forming corrosive and poisonous hydrogen halides. In this work experiments have been performed investigating the formation of HCl and HF from a molten salt consisting of a 13.8 wt% CaF2 in CaCl2 eutectic exposed to a flowing gas consisting of 10 vol% H2O in N2. Hydrolysis has been investigated as function of content of CaO and temperature. HCl and HF are shown to be formed at elevated temperatures; HCl forms to a substantially larger extent than HF. Addition of CaO has a marked, limiting effect on the hydrolysis. Thermodynamic modeling of the reaction indicates activity coefficients for CaO above unity in the system. For cyclic CO2-capture based on thermal swing, it is advisable to keep the temperature in the carbonation (absorption reactor well below 850 ℃ while maintaining a high CaO content if molten CaCl2 is employed. Similar conclusions can be drawn with regards to CaF2.

  6. Preparation of core-shell structured CaCO3 microspheres as rapid and recyclable adsorbent for anionic dyes

    Science.gov (United States)

    Zhao, Mengen; Chen, Zhenhua; Lv, Xinyan; Zhou, Kang; Zhang, Jie; Tian, Xiaohan; Ren, Xiuli; Mei, Xifan

    2017-09-01

    Core-shell structured CaCO3 microspheres (MSs) were prepared by a facile, one-pot method at room temperature. The adsorbent dosage and adsorption time of the obtained CaCO3 MSs were investigated. The results suggest that these CaCO3 MSs can rapidly and efficiently remove 99-100% of anionic dyes within the first 2 min. The obtained CaCO3 MSs have a high Brunauer-Emmett-Teller surface area (211.77 m2 g-1). In addition, the maximum adsorption capacity of the obtained CaCO3 MSs towards Congo red was 99.6 mg g-1. We also found that the core-shell structured CaCO3 MSs have a high recycling capability for removing dyes from water. Our results demonstrate that the prepared core-shell structured CaCO3 MSs can be used as an ideal, rapid, efficient and recyclable adsorbent to remove dyes from aqueous solution.

  7. Characteristics of the binding of (/sup 3/H)nitrendipine to rabbit ventricular membranes: modification by other Ca++ channel antagonists and by the Ca++ channel agonist Bay K 8644

    Energy Technology Data Exchange (ETDEWEB)

    Janis, R.A.; Sarmiento, J.G.; Maurer, S.C.; Bolger, G.T.; Triggle, D.J.

    1984-10-01

    This study was carried out to characterize (/sup 3/H)nitrendipine binding to cardiac membranes and to test the hypothesis that high affinity binding of Ca++ channel antagonists and agonists is to Ca++ channels. Binding was specific, rapid, reversible and stereoselective. The relative order of potency of nifedipine analogs for inhibition of binding was the same as that for inhibition of smooth and cardiac muscle contraction. Results with diltiazem, verapamil and lidoflazine were consistent with the hypothesis that nondihydropyridine Ca++ channel antagonists act at one or more sites allosterically linked to the 1,4-dihydropyridine site in cardiac cells. The Ca++ channel agonist Bay K 8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyridine- 5-carboxylate) displaced specifically bound (/sup 3/H)nitrendipine in an apparently competitive manner with an IC50 value of 5 nM. The results suggest that organic antagonists do not act by physically blocking the Ca++ channel. The data also support the hypothesis that the high affinity binding sites for (/sup 3/H)nitrendipine in isolated cardiac membranes are associated with Ca++ channels that are inactivated or are otherwise unavailable for opening.

  8. MIRO-1 Determines Mitochondrial Shape Transition upon GPCR Activation and Ca2+ Stress

    Directory of Open Access Journals (Sweden)

    Neeharika Nemani

    2018-04-01

    Full Text Available Summary: Mitochondria shape cytosolic calcium ([Ca2+]c transients and utilize the mitochondrial Ca2+ ([Ca2+]m in exchange for bioenergetics output. Conversely, dysregulated [Ca2+]c causes [Ca2+]m overload and induces permeability transition pore and cell death. Ablation of MCU-mediated Ca2+ uptake exhibited elevated [Ca2+]c and failed to prevent stress-induced cell death. The mechanisms for these effects remain elusive. Here, we report that mitochondria undergo a cytosolic Ca2+-induced shape change that is distinct from mitochondrial fission and swelling. [Ca2+]c elevation, but not MCU-mediated Ca2+ uptake, appears to be essential for the process we term mitochondrial shape transition (MiST. MiST is mediated by the mitochondrial protein Miro1 through its EF-hand domain 1 in multiple cell types. Moreover, Ca2+-dependent disruption of Miro1/KIF5B/tubulin complex is determined by Miro1 EF1 domain. Functionally, Miro1-dependent MiST is essential for autophagy/mitophagy that is attenuated in Miro1 EF1 mutants. Thus, Miro1 is a cytosolic Ca2+ sensor that decodes metazoan Ca2+ signals as MiST. : Metazoan Ca2+ signal determines mitochondrial shape transition (MiST and cellular quality control. Nemani et al. find that mitochondria undergo shape changes upon Ca2+ stress. MiST is distinct from matrix Ca2+-induced swelling and mitochondrial dynamics. The conserved Ca2+ sensor Miro1 enables MiST and promotes autophagy/mitophagy. Keywords: mitochondrial shape, MiST, calcium, Miro, EF hand, PTP, MCU, mitophagy, autophagy, mitochondrial dynamics

  9. Investigation of structural and optical properties of CaTiO3 powders doped with Mg2+ and Eu3+ ions

    International Nuclear Information System (INIS)

    Oliveira, Larissa H.; Savioli, Julia; Moura, Ana P. de; Nogueira, Içamira C.; Li, Maximo S.; Longo, Elson; Varela, José A.; Rosa, Ieda L.V.

    2015-01-01

    In this work, CaTiO 3 powders doped with Mg 2+ ions and CaTiO 3 powders co-doped with Mg 2+ and Eu 3+ ions were prepared by the polymeric precursor method (PPM). These powders were characterized by different characterization techniques to study the influence of Mg 2+ doping as well as Mg 2+ and Eu 3+ co-doping in structural and optical properties of CaTiO 3 perovskite-type structure. The Rietveld refinement and Micro-Raman analyses suggested the substitution Mg 2+ and Eu 3+ ions in the A-site of CaTiO 3 perovskite. The influence of Mg 2+ doping can be detected by the displacement of calcium and oxygen atomic positions when compared to the non-doped CaTiO 3 powder. When Eu 3+ ions are added to the A-site of this perovskite the excess of positive charge can be compensated by the formation of calcium vacancies. Luminescence data showed that Ca 1-x Mg x TiO 3 and Ca 1x Mg x/2 Eu 2y/3 TiO 3 powders are potential materials for fabrication of lighting devices based on near-UV and blue LED using an excitation wavelength of 397 and/or 450 nm. - Highlights: • CaTiO 3 co-doped with Mg 2+ and Eu 3+ were obtained by the Polymeric Precursor Method. • Incorporation of Mg 2+ and Eu 3+ ions in the CaTiO 3 lattice. • Enhancement of the Eu 3+ photoluminescence

  10. UV-induced photoluminescence and thermally stimulated luminescence of CaSO{sub 4}:Eu and CaF{sub 2}:Tb{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Godbole, S.V.; Nagpal, J.S.; Page, A.G. E-mail: agpage@magnum.barc.ernet.in

    2000-08-15

    Ultraviolet radiation induced changes in photoluminescence (PL) and thermally stimulated luminescence (TSL) of europium activated calcium sulphate (CaSO{sub 4}:Eu{sup 3+}, Eu{sup 2+}) and terbium doped calcium fluoride (CaF{sub 2}:Tb{sup 3+}) phosphors have been studied. PL measurements suggest conversion of Eu{sup 3+} to Eu{sup 2+} on 254 nm irradiation corresponding to charge transfer band of Eu{sup 3+} ions and reduction of Eu{sup 2+} ions with 365 nm illumination representing a f-d transition of Eu{sup 2+} ions. Similar studies carried out on CaF{sub 2}:Tb{sup 3+} phosphor, however, do not show any significant wavelength specific changes. The integrated TSL output appears to be rate-dependent for both phosphors. The wavelength dependent changes in TSL output observed for CaSO{sub 4}:Eu phosphor have been correlated with those obtained in PL studies. The changes in TSL and PL characteristics of CaF{sub 2}:Tb{sup 3+} phosphor have been explained on the basis of stabilisation of traps based on matrix specific charge similarities.

  11. Influence of ER leak on resting cytoplasmic Ca2+ and receptor-mediated Ca2+ signalling in human macrophage.

    Science.gov (United States)

    Layhadi, Janice A; Fountain, Samuel J

    2017-06-03

    Mechanisms controlling endoplasmic reticulum (ER) Ca 2+ homeostasis are important regulators of resting cytoplasmic Ca 2+ concentration ([Ca 2+ ] cyto ) and receptor-mediated Ca 2+ signalling. Here we investigate channels responsible for ER Ca 2+ leak in THP-1 macrophage and human primary macrophage. In the absence of extracellular Ca 2+ we employ ionomycin action at the plasma membrane to stimulate ER Ca 2+ leak. Under these conditions ionomycin elevates [Ca 2+ ] cyto revealing a Ca 2+ leak response which is abolished by thapsigargin. IP 3 receptors (Xestospongin C, 2-APB), ryanodine receptors (dantrolene), and translocon (anisomycin) inhibition facilitated ER Ca 2+ leak in model macrophage, with translocon inhibition also reducing resting [Ca 2+ ] cyto . In primary macrophage, translocon inhibition blocks Ca 2+ leak but does not influence resting [Ca 2+ ] cyto . We identify a role for translocon-mediated ER Ca 2+ leak in receptor-mediated Ca 2+ signalling in both model and primary human macrophage, whereby the Ca 2+ response to ADP (P2Y receptor agonist) is augmented following anisomycin treatment. In conclusion, we demonstrate a role of ER Ca 2+ leak via the translocon in controlling resting cytoplasmic Ca 2+ in model macrophage and receptor-mediated Ca 2+ signalling in model macrophage and primary macrophage. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Chemical stability and defect formation in CaHfO3

    KAUST Repository

    Alay-E-Abbas, Syed Muhammad

    2014-04-01

    Defects in CaHfO3 are investigated by ab initio calculations based on density functional theory. Pristine and anion-deficient CaHfO 3 are found to be insulating, whereas cation-deficient CaHfO 3 is hole-doped. The formation energies of neutral and charged cation and anion vacancies are evaluated to determine the stability in different chemical environments. Moreover, the energies of the partial and full Schottky defect reactions are computed. We show that clustering of anion vacancies in the HfO layers is energetically favorable for sufficiently high defect concentrations and results in metallicity. © 2014 EPLA.

  13. Chemical stability and defect formation in CaHfO3

    KAUST Repository

    Alay-E-Abbas, Syed Muhammad; Nazir, Safdar; Mun Wong, Kin; Shaukat, Ali; Schwingenschlö gl, Udo

    2014-01-01

    Defects in CaHfO3 are investigated by ab initio calculations based on density functional theory. Pristine and anion-deficient CaHfO 3 are found to be insulating, whereas cation-deficient CaHfO 3 is hole-doped. The formation energies of neutral and charged cation and anion vacancies are evaluated to determine the stability in different chemical environments. Moreover, the energies of the partial and full Schottky defect reactions are computed. We show that clustering of anion vacancies in the HfO layers is energetically favorable for sufficiently high defect concentrations and results in metallicity. © 2014 EPLA.

  14. Synthesis and Characterization of Nd(3+)-Doped CaF2 Nanoparticles.

    Science.gov (United States)

    Yuan, Dan; Li, Weiwei; Mei, Bingchu; Song, Jinghong

    2015-12-01

    The Ca(1-x)F(2+x):Nd(x) nanoparticles were synthesized by chemical direct precipitation method. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Image analyzer, absorption spectrum and transmittance were taken to characterization the phases, morphologies, sizes, size distribution and optical properties of the samples. The results indicate that the Ca(1-x)F(2+x):Nd(x) samples can be rationally modified in size and morphology by altering the Nd3+ ions doping concentration. With increasing concentration of Nd3+ ions, the particle size decreased from 24 to 14 nm, the intensity of the diffraction peaks decreased, the Ca(1-x)F(2+x):Nd(x) particles aggregated ion of the formed clusters which should have an effect on both speed and orientation of the particles growth. The transmittance of ceramics with a thickness of 2 mm showed that the transmittance can reach 90% when the doping concentration was 5%, which should be profitable for LD pumping.

  15. Giant magnetostructural coupling in Gd{sub 2/3}Ca{sub 1/3}MnO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Correa, V F; Nieva, G; Haberkorn, N [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, 8400 S. C. de Bariloche (Argentina); Saenger, N [Fachbereich Physik, Universitaet Konstanz, D-78457 Konstanz (Germany); Jorge, G, E-mail: victor.correa@cab.cnea.gov.a [Departamento de Fisica, FCEyN, Universidad de Buenos Aires (Argentina)

    2009-05-01

    We report high magnetic field magnetostructural studies on Gd{sub 2/3}Ca{sub 1/3}MnO{sub 3} single crystals. A giant linear magnetostrictive effect is observed in a wide temperature range (T < 120 K). Above 25 K a large hysteresis is seen reflecting the Mn magnetic moments ordering. At lower temperature (T < 15 K), a rather complicated field dependence arising from the competition between the Mn and Gd magnetic sublattices is observed. The relevance of the Gd ions in the low temperature behavior is further corroborated by specific heat experiments.

  16. Revising the Subsystem Nurse’s A-Phase-Silicocarnotite within the System Ca3(PO42–Ca2SiO4

    Directory of Open Access Journals (Sweden)

    Patricia Ros-Tárraga

    2016-04-01

    Full Text Available The subsystem Nurse’s A-phase-silicocarnotite within the system Ca3(PO42–Ca2SiO4 was conducted as a preliminary step toward obtaining new biomaterials with controlled microstructures. Phase composition of the resulting ceramics was studied by X-ray diffraction, differential thermal analysis, and scanning electron microscopy with attached wavelength dispersive spectroscopy. The results showed that the sub-system presents an invariant eutectoid point at 1366 ± 4 °C with a composition of 59.5 wt % Ca3(PO42 and 40.5 wt % Ca2SiO4, and typical eutectoid microstructure of lamellae morphology. These results are in disagreement with the previous reported data, which locate the invariant eutectoid point at 1250 ± 20 °C with a composition of 55 wt % Ca3(PO42 and 45 wt % Ca2SiO4. In addition, cell attachment testing showed that the new eutectoid material supported the mesenchymal stem cell adhesion and spreading, and the cells established close contact with the ceramic after 28 days of culture. These findings indicate that the new ceramic material with eutectoid microstructure of lamellae morphology possesses good bioactivity and biocompatibility and might be a promising bone implant material.

  17. High-temperature crystal chemistry of layered calcium borosilicates: CaBSiO4(OH) (datolite), Ca4B5Si3O15(OH)5 (`bakerite') and Ca2B2SiO7 (synthetic analogue of okayamalite)

    Science.gov (United States)

    Krzhizhanovskaya, Maria G.; Gorelova, L. A.; Bubnova, R. S.; Pekov, I. V.; Krivovichev, S. V.

    2018-05-01

    The high-temperature behaviour of three Ca borosilicates has been studied by in situ powder high-temperature X-ray diffraction (HTXRD), differential scanning calorimetry and thermogravimetry in the temperature range 30-900 °C for natural samples of datolite, CaBSiO4(OH), and `bakerite', Ca4B5Si3O15(OH)5, and a synthetic analogue of okayamalite, Ca2B2SiO7. The latter was obtained by heating datolite at 800 °C for 5 h. Datolite and bakerite start to dehydroxylate above 700 and 500 °C, respectively, and decompose fully to form a high-temperature modification of okayamalite, HT-Ca2B2SiO7, and wollastonite, CaSiO3 at about 730 °C. Above 900 °C, HT-okayamalite decomposes with the formation of wollastonite, CaSiO3, and metaborate CaB2O4. The latter melts at about 990 °C. Above 1000 °C, only the existence of wollastonite, CaSiO3 and cristobalite, SiO2 was observed. According to the HTXRD data, in the temperature range 30-500 °C, datolite and `bakerite' demonstrate very similar and relatively low volumetric thermal expansion: α v = 29 and 27 × 10-6 °C-1, respectively. A high thermal expansion anisotropy ( α max/ α min 3) is caused by both the layered character of the crystal structures and the shear deformations of their monoclinic unit cells. The direction of maximum expansion is intermediate between the normal direction to the layers and the ( a + c) vector. A possible transformation mechanism from the datolite to the okayamalite structure topology is proposed from geometrical considerations. The synthetic analogue of okayamalite, Ca2B2SiO7, undergoes a reversible polymorphic transition at about 550 °C with a decrease in symmetry from tetragonal to orthorhombic. The crystal structure of the high-temperature (HT) modification of okayamalite was solved from the powder-diffraction data [900 °C: P21212, a = 7.3361(4), b = 7.1987(4), c = 4.8619(4) Å, V = 256.76(3) Å3, R wp = 6.61, R Bragg = 2.68%].

  18. Hippocampal deletion of BDNF gene attenuates gamma oscillations in area CA1 by up-regulating 5-HT3 receptor.

    Directory of Open Access Journals (Sweden)

    Ying Huang

    2011-01-01

    Full Text Available Pyramidal neurons in the hippocampal area CA3 express high levels of BDNF, but how this BDNF contributes to oscillatory properties of hippocampus is unknown.Here we examined carbachol-induced gamma oscillations in hippocampal slices lacking BDNF gene in the area CA3. The power of oscillations was reduced in the hippocampal area CA1, which coincided with increases in the expression and activity of 5-HT3 receptor. Pharmacological block of this receptor partially restored power of gamma oscillations in slices from KO mice, but had no effect in slices from WT mice.These data suggest that BDNF facilitates gamma oscillations in the hippocampus by attenuating signaling through 5-HT3 receptor. Thus, BDNF modulates hippocampal oscillations through serotonergic system.

  19. Magnetic Field Effects on CaCO3 Precipitation Process in Hard Water

    Directory of Open Access Journals (Sweden)

    Nelson Saksono

    2010-10-01

    Full Text Available Magnetic treatment is applied as physical water treatment for scale prevention especially CaCO3, from hard water in piping equipment by reducing its hardness.Na2CO3 and CaCl2 solution sample was used in to investigate the magnetic fields influence on the formation of particle of CaCO3. By changing the strength of magnetic fields, exposure time and concentration of samples solution, this study presents quantitative results of total scale deposit, total precipitated CaCO3 and morphology of the deposit. This research was run by comparing magnetically and non-magnetically treated  samples. The results showed an increase of deposits formation rate and total number of precipitated CaCO3 of magnetically treated samples. The increase of concentration solution sample will also raised the deposit under magnetic  field. Microscope images showed a greater number but smaller size of CaCO3 deposits form in magnetically treated samples, and aggregation during the processes. X-ray diffraction (XRD analysis showed that magnetically samples were dominated by calcite. But, there was a significant decrease of calcite’s peak intensities from magnetized  samples that indicated the decrease of the amount of calcite and an increase of total amorphous of deposits. This result  showed that magnetization of hard water leaded to the decreasing of ion Ca2+ due to the increasing of total CaCO3 precipitation process.

  20. Synthesis and photoluminescence properties of Sm3+-doped CaWO4 nanoparticles

    International Nuclear Information System (INIS)

    Xiao Qi; Zhou Qitao; Li Ming

    2010-01-01

    The Sm 3+ -doped CaWO 4 nanoparticles were synthesized by hydrothermal method. The room temperature photoluminescence (PL) spectra of Sm 3+ -doped CaWO 4 nanoparticles doped with different Sm 3+ concentrations under 405 nm excitation have been investigated. The PL spectra showed four strong emission peaks at 460, 571, 609, and 653 nm. The first emission peak at 460 nm could be due to a structural defect of the lattice, an oxygen-deficient WO 3 complex. The other three emissions at 571, 609, and 653 nm were due to the f-f forbidden transitions of the 4f electrons of Sm 3+ , corresponding to 4 G 5/2 → 6 H 5/2 (571 nm), 6 H 7/2 (609 nm), and 6 H 9/2 (653 nm), respectively. In addition, the optimum Sm 3+ concentration in CaWO 4 nanoparticles for optical emission was determined to be 1.0%. The Sm 3+4 G 5/2 → 6 H 7/2 (609 nm) emission intensity of Sm 3+ -doped CaWO 4 nanoparticles significantly increased with the increase of Sm 3+ concentration, and showed a maximum when Sm 3+ doping content was 1.0%. If Sm 3+ concentration continued to increase, namely more than 1.0%, the Sm 3+4 G 5/2 → 6 H 7/2 emission intensity would decrease. The present materials might be a promising phosphor for white-light LED applications.

  1. Numerical study of IP3-induced Ca2+ spiral pattern evolution

    International Nuclear Information System (INIS)

    Tang Jun; Ma Jun; Yi Ming; Jia Ya

    2008-01-01

    The effect of change in concentration of messenger molecule inositol 1,4,5-trisphosphate (IP 3 ) on intracellular Ca 2+ spiral pattern evolution is studied numerically. The results indicate that when the IP 3 concentration decreases from 0.27 μM, a physiologically reasonable value, to different values, the spiral centre drifts to the edge of the medium and disappears for a small enough IP 3 concentration. The instability of spiral pattern can be understood in terms of excitability-change controlled by the IP 3 concentration. On the other hand, when the IP 3 concentration increases from 0.27 μM, a homogeneous area with a high Ca 2+ concentration emerges and competes with the spiral pattern. A high enough IP 3 concentration can lead the homogeneous area to occupy the whole medium. The instability of spiral pattern is ascribed to the change in stability of a stationary state with a high Ca 2+ concentration. (general)

  2. The Pr and Ca substitution in GdBa2Cu3O7-8

    International Nuclear Information System (INIS)

    Shakeri, H.; Akhavan, M.

    2002-01-01

    The granular Gd 1 -x-zPr x Ca z Ba 2 Cu 3 O 7 -8 (Gd Pr Ca-123) high-temperature cuprate samples with 0.0≤x≤0.3 and 0.0≤z≤0.35 are prepared by standard solid state reaction and characterized by XRD and SEM techniques. The BaCuO 2 and impurity phases are less than 1% in the samples having high levels of Pr and Ca concentrations. The electrical resistivity measurements show a nonlinear reduction in T c (x,z=etc) versus x. Moreover, the T c (z) curve with x=0 is nonlinear and a plateau appears at z≅0.05-0.015. For Pr-Ca-doped samples with a constant concentration of Pr, T c increases with the increase of Ca up to an optimum value of Ca doping and then in decreases. Based on these observations, we suggest that hole filling and hole localization the main effects of Pr ion substitution. The magnetic measurements indicate that the value of H C 1 is in the order of 10 m T. The magnetoresistance measurements have been measured and analyzed. The superconducting transition region is broadened by the application of magnetic field. The experimental data near the on sen of superconductivity are fitted with the Ambegakor and Halperin (A H) phase-slip model. We observe that the A H parameter, γ(H), depends not only on the temperature and the magnetic field, but also on the Pr and Ca ions concentrations. It is observed that the critical current density increases with Ca substitution and decreases with pr substitution in Gd-123 system. We suggest that the pr ion substitution probably enhances the weak link, but the Ca ion acts as flux pinning center in the Gd Pr Ca-123 system

  3. Extremely Elevated CA 125 and CA 19-9 in Endometrioma; A Case Series

    Directory of Open Access Journals (Sweden)

    Vugar Bayramov

    2010-03-01

    Full Text Available Although endometriosis is a benign condition, increased levels of the tumor markers CA 125 and CA 19-9 may be seen. However, these tumor markers reach to very high levels, rarely. In this report, 4 patients between 20 and 43 year-old with extremely elevated CA 125, CA 19-9 and CA 15-3 levels are discussed. In endometriosis extremely increased tumor markers are determined in the case of ruptured endometrioma cyst. There are two mechanisms to clarify extremely elevated levels of CA 125 in endometriosis. First, the peritoneal irritation of CA 125 molecule after the rupture of endometioma cyst and CA 125 secretion from the periton. And the second is penetration of the CA 125 moecule easily to the circulation through the peritoneal endothelial surface after the cyst rupture. In conclusion, the diagnosis of ruptured endometrioma cyst should be kept in mind especially in young patients with extremely elevated serum CA 125 levels with regard to the history and ultrasonographical signs and invasive procedures should be avoided.

  4. Entorhinal-CA3 Dual-Input Control of Spike Timing in the Hippocampus by Theta-Gamma Coupling.

    Science.gov (United States)

    Fernández-Ruiz, Antonio; Oliva, Azahara; Nagy, Gergő A; Maurer, Andrew P; Berényi, Antal; Buzsáki, György

    2017-03-08

    Theta-gamma phase coupling and spike timing within theta oscillations are prominent features of the hippocampus and are often related to navigation and memory. However, the mechanisms that give rise to these relationships are not well understood. Using high spatial resolution electrophysiology, we investigated the influence of CA3 and entorhinal inputs on the timing of CA1 neurons. The theta-phase preference and excitatory strength of the afferent CA3 and entorhinal inputs effectively timed the principal neuron activity, as well as regulated distinct CA1 interneuron populations in multiple tasks and behavioral states. Feedback potentiation of distal dendritic inhibition by CA1 place cells attenuated the excitatory entorhinal input at place field entry, coupled with feedback depression of proximal dendritic and perisomatic inhibition, allowing the CA3 input to gain control toward the exit. Thus, upstream inputs interact with local mechanisms to determine theta-phase timing of hippocampal neurons to support memory and spatial navigation. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Basal activity of voltage-gated Ca(2+) channels controls the IP3-mediated contraction by α(1)-adrenoceptor stimulation of mouse aorta segments.

    Science.gov (United States)

    Leloup, Arthur J; Van Hove, Cor E; De Meyer, Guido R Y; Schrijvers, Dorien M; Fransen, Paul

    2015-08-05

    α1-Adrenoceptor stimulation of mouse aorta causes intracellular Ca(2+) release from sarcoplasmic reticulum Ca(2+) stores via stimulation of inositoltriphosphate (IP3) receptors. It is hypothesized that this Ca(2+) release from the contractile and IP3-sensitive Ca(2+) store is under the continuous dynamic control of time-independent basal Ca(2+) influx via L-type voltage-gated Ca(2+) channels (LCC) residing in their window voltage range. Mouse aortic segments were α1-adrenoceptor stimulated with phenylephrine in the absence of external Ca(2+) (0Ca) to measure phasic isometric contractions. They gradually decreased with time in 0Ca, were inhibited with 2-aminoethoxydiphenyl borate, and declined with previous membrane potential hyperpolarization (levcromakalim) or with previous inhibition of LCC (diltiazem). Former basal stimulation of LCC with depolarization (15 mM K(+)) or with BAY K8644 increased the subsequent phasic contractions by phenylephrine in 0Ca. Although exogenous NO (diethylamine NONOate) reduced the phasic contractions by phenylephrine, stimulation of endothelial cells with acetylcholine in 0Ca failed to attenuate these phasic contractions. Finally, inhibition of the basal release of NO with N(Ω)-nitro-L-arginine methyl ester also attenuated the phasic contractions by phenylephrine. Results indicated that α1-adrenoceptor stimulation with phenylephrine causes phasic contractions, which are controlled by basal LCC and endothelial NO synthase activity. Endothelial NO release by acetylcholine was absent in 0Ca. Given the growing interest in the active regulation of arterial compliance, the dependence of contractile SR Ca(2+) store-refilling in basal conditions on the activity of LCC and basal eNOS may contribute to a more thorough understanding of physiological mechanisms leading to arterial stiffness. Copyright © 2015. Published by Elsevier B.V.

  6. Analysis of PIK3CA Mutations and Activation Pathways in Triple Negative Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Paolo Cossu-Rocca

    Full Text Available Triple Negative Breast Cancer (TNBC accounts for 12-24% of all breast carcinomas, and shows worse prognosis compared to other breast cancer subtypes. Molecular studies demonstrated that TNBCs are a heterogeneous group of tumors with different clinical and pathologic features, prognosis, genetic-molecular alterations and treatment responsivity. The PI3K/AKT is a major pathway involved in the regulation of cell survival and proliferation, and is the most frequently altered pathway in breast cancer, apparently with different biologic impact on specific cancer subtypes. The most common genetic abnormality is represented by PIK3CA gene activating mutations, with an overall frequency of 20-40%. The aims of our study were to investigate PIK3CA gene mutations on a large series of TNBC, to perform a wider analysis on genetic alterations involving PI3K/AKT and BRAF/RAS/MAPK pathways and to correlate the results with clinical-pathologic data.PIK3CA mutation analysis was performed by using cobas® PIK3CA Mutation Test. EGFR, AKT1, BRAF, and KRAS genes were analyzed by sequencing. Immunohistochemistry was carried out to identify PTEN loss and to investigate for PI3K/AKT pathways components.PIK3CA mutations were detected in 23.7% of TNBC, whereas no mutations were identified in EGFR, AKT1, BRAF, and KRAS genes. Moreover, we observed PTEN loss in 11.3% of tumors. Deregulation of PI3K/AKT pathways was revealed by consistent activation of pAKT and p-p44/42 MAPK in all PIK3CA mutated TNBC.Our data shows that PIK3CA mutations and PI3K/AKT pathway activation are common events in TNBC. A deeper investigation on specific TNBC genomic abnormalities might be helpful in order to select patients who would benefit from current targeted therapy strategies.

  7. Analysis of PIK3CA Mutations and Activation Pathways in Triple Negative Breast Cancer.

    Science.gov (United States)

    Cossu-Rocca, Paolo; Orrù, Sandra; Muroni, Maria Rosaria; Sanges, Francesca; Sotgiu, Giovanni; Ena, Sara; Pira, Giovanna; Murgia, Luciano; Manca, Alessandra; Uras, Maria Gabriela; Sarobba, Maria Giuseppina; Urru, Silvana; De Miglio, Maria Rosaria

    2015-01-01

    Triple Negative Breast Cancer (TNBC) accounts for 12-24% of all breast carcinomas, and shows worse prognosis compared to other breast cancer subtypes. Molecular studies demonstrated that TNBCs are a heterogeneous group of tumors with different clinical and pathologic features, prognosis, genetic-molecular alterations and treatment responsivity. The PI3K/AKT is a major pathway involved in the regulation of cell survival and proliferation, and is the most frequently altered pathway in breast cancer, apparently with different biologic impact on specific cancer subtypes. The most common genetic abnormality is represented by PIK3CA gene activating mutations, with an overall frequency of 20-40%. The aims of our study were to investigate PIK3CA gene mutations on a large series of TNBC, to perform a wider analysis on genetic alterations involving PI3K/AKT and BRAF/RAS/MAPK pathways and to correlate the results with clinical-pathologic data. PIK3CA mutation analysis was performed by using cobas® PIK3CA Mutation Test. EGFR, AKT1, BRAF, and KRAS genes were analyzed by sequencing. Immunohistochemistry was carried out to identify PTEN loss and to investigate for PI3K/AKT pathways components. PIK3CA mutations were detected in 23.7% of TNBC, whereas no mutations were identified in EGFR, AKT1, BRAF, and KRAS genes. Moreover, we observed PTEN loss in 11.3% of tumors. Deregulation of PI3K/AKT pathways was revealed by consistent activation of pAKT and p-p44/42 MAPK in all PIK3CA mutated TNBC. Our data shows that PIK3CA mutations and PI3K/AKT pathway activation are common events in TNBC. A deeper investigation on specific TNBC genomic abnormalities might be helpful in order to select patients who would benefit from current targeted therapy strategies.

  8. Boron-purity-dependent Raman spectra of CaB6

    International Nuclear Information System (INIS)

    Song, M.; Yang, I. S.; Kim, J. Y.; Cho, B. K.

    2006-01-01

    We report significant differences in the Raman spectra of two different kinds of CaB 6 single crystals grown from boron with a purity of 99.9 % (3N) or 99.9999 % (6N). Our Raman spectra of CaB 6 (3N) show peaks around 781 (T 2g ), 1141 (E g ), and 1283 cm -1 (A 1g ), and they are very similar to previous Raman spectra of CaB 6 . The E g mode shows a characteristic double-peak feature due to an additional weak broad peak centered around 1158 cm -1 . However, the Raman spectra of CaB 6 (6N) show sharp peaks around 771 (T 2g ), 1137 (E g ), and 1266 cm -1 (A 1g ). The peak frequencies are down shifted as much as ∼17 cm -1 . In addition, no additional peak feature is observed for the E g mode so that the mode is symmetric in the case of CaB 6 (6N). The X-ray powder diffraction patterns for both CaB 6 (3N) and CaB 6 (6N) show that the lattice parameters are essentially the same. The majority of the impurity in the 99.9 %-pure (3N) boron is C. Thus, we doped CaB 6 (6N) with C, making Ca(B 0.995 C 0.005 ) 6 , and looked for differences in the Raman spectra. The Raman spectra of Ca(B 0.995 C 0.005 ) 6 are nearly identical to those of CaB 6 (6N), indicating that the differences between the Raman spectra of CaB 6 (3N) and CaB 6 (6N) are not due to a C impurity. The Raman results show that the presence of impurities, not the amount of them, is enough to trigger local symmetry breaking in CaB 6 . The broadening of T 2g , the additional E g2 mode and the asymmetry of A 1g in CaB 6 (3N) can be understood in terms of the symmetry of the arrangements of the boron octahedra lowered by local symmetry breaking.

  9. Effects of vitamin D metabolites on cellular Ca2+ and on Ca transport in primary cultures of bone cells.

    Science.gov (United States)

    Eilam, Y; Szydel, N; Harell, A

    1980-09-01

    Both 1,25-dihydroxycholecalciferol (1,25(OH)2D3) and 24,25-dihydroxycholecalciferol (24,25(OH)2D3) exerted direct effects on Ca2+ transport and accumulation in primary cultures of bone cells. The following changes were recorded. (1) A significant decrease in the amount of intracellular exchangeable Ca2+. (2) A marked increase in the rate constants of efflux from the 'slow'-turnover intracellular Ca pool. (3) A marked increase in the 'initial rate' of Ca influx into the cells. Thus, vitamin D metabolites caused an increase in the turnover of Ca2+ in bone cells and altered the steady-stae level of intracellular exchangeable Ca2+. Whereas the changes in the rate of efflux were abolished in the presence of inhibitors of protein synthesis, the increase in the rate of influx was not sensitive to these inhibitors. It is suggested that the changes in the two fluxes were mediated by different mechanisms and that the changes in influx were due to a direct effect of vitamin D metabolites on the cellular membranes.

  10. High-pressure crystal growth and electromagnetic properties of 5d double-perovskite Ca3OsO6

    International Nuclear Information System (INIS)

    Feng, Hai Luke; Shi, Youguo; Guo, Yanfeng; Li, Jun; Sato, Akira; Sun, Ying; Wang, Xia; Yu, Shan; Sathish, Clastin I.; Yamaura, Kazunari

    2013-01-01

    Single crystals of the osmium-containing compound Ca 3 OsO 6 have been successfully grown under high-pressure conditions, for the first time. The crystal structure of Ca 3 OsO 6 were characterized as an ordered double-perovskite structure of space group P2 1 /n with the Ca and Os atoms being fully ordered at the perovskite B-site. The electromagnetic analysis shows that the crystal exhibits a semiconductor-like behavior below 300 K and undergoes an antiferromagnetic transition at 50 K. - Graphical Abstract: Schematic image of crystal structure of Ca 3 OsO 6 as determined by X-ray diffraction, where the gray and black octahedrons are occupied by Ca and Os, respectively. Top inset reveals an optic image of a typical Ca 3 OsO 6 single crystal. Highlights: ► Single crystals of Ca 3 OsO 6 have been successfully grown under high-pressure. ► Ca 3 OsO 6 crystalizes into an ordered double-perovskite structure. ► The Ca 3 OsO 6 undergoes an antiferromagnetic transition at 50 K

  11. Chemical solution deposition of CaCu3Ti4O12 thin film

    Indian Academy of Sciences (India)

    Administrator

    CaCu3Ti4O12; thin film; chemical solution deposition; dielectric properties. 1. Introduction. The CaCu3Ti4O12. (CCTO) compound has recently attracted considerable ... and Kelvin probe force microscopy (Chung et al 2004). Intrinsic .... SEM images of CCTO thin films as a function of sintering temperature. silicon based ...

  12. Dielectric and piezoelectric properties of sol-gel derived Ca doped PbTiO3

    International Nuclear Information System (INIS)

    Chauhan, Arun Kumar Singh; Gupta, Vinay; Sreenivas, K.

    2006-01-01

    Synthesis of Ca doped PbTiO 3 powder by a chemically derived sol-gel process is described. Crystallization characteristics of different compositions Pb 1-x Ca x TiO 3 (PCT) with varying calcium (Ca) content in the range x = 0-0.45 has been investigated by DTA/TGA, X-ray diffraction and scanning electron microscopy. The crystallization temperature is found to decrease with increasing calcium content. X-ray diffraction reveals a tetragonal structure for PCT compositions with x ≤ 0.35, and a cubic structure for x = 0.45. Dielectric properties on sintered ceramics prepared with fine sol-gel derived powders have been measured. The dielectric constant is found to increase with increasing Ca content, and the dielectric loss decreases continuously. Sol-gel derived Pb 1-x Ca x TiO 3 ceramics with x = 0.45 after poling exhibit infinite electromechanical anisotropy (k t /k p ) with a high d 33 = 80 pC/N, ε' = 298 and low dielectric loss (tan δ = 0.0041)

  13. Synthesis and characterization of Er3+ doped CaF2 nanoparticles

    International Nuclear Information System (INIS)

    Zhi Guanglin; Song Jinghong; Mei Bingchu; Zhou Weibing

    2011-01-01

    Highlights: → Er 3+ :CaF 2 nanoparticles were synthesized by co-precipitation method with particle size of 8-36 nm. → Increasing dopant concentration increases lattice constants and decreases grain size. → Annealing treatment has a remarkable effect on luminescence properties. → Luminescence intensity decrease with the increasing of the dopant concentration. - Abstract: Er 3+ doped CaF 2 nanoparticles were synthesized by a chemical co-precipitation method. Effect of the dopant concentrations on the structure and optical properties of the CaF 2 nanoparticles was investigated. The X-ray powder diffraction and transmission electron microscopy analysis was used to characterize the structure and morphology of the nanoparticles. The nanoparticles with different dopant concentration exhibited a sphere-like morphology with diameters of about 8-36 nm. The incorporation of Er 3+ ions into CaF 2 resulted in the decrease in grain size and deterioration of crystallinity, but enlarged the lattice constants of CaF 2 . Additional annealing treatment at 400 deg. C to the prepared CaF 2 removed the NO 3 - and OH - groups adsorbed on the particles' surfaces, and improved the optical properties of the nanoparticles. The fluorescence intensity, with a maximum at approximately 0.4 mol%, decreased with the increase in doping concentration because of concentration quenching.

  14. Age-dependent changes in diastolic Ca{sup 2+} and Na{sup +} concentrations in dystrophic cardiomyopathy: Role of Ca{sup 2+} entry and IP{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Mijares, Alfredo [Instituto Venezolano de Investigaciones Científicas, Centro de Biofísica y Bioquímica, Caracas (Venezuela, Bolivarian Republic of); Altamirano, Francisco [Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616 (United States); Kolster, Juan [Centro de Investigaciones Biomédicas, México D.F. (Mexico); Adams, José A. [Division of Neonatology, Mount Sinai Medical Center, Miami, FL 33140 (United States); López, José R., E-mail: jrlopez@ucdavis.edu [Instituto Venezolano de Investigaciones Científicas, Centro de Biofísica y Bioquímica, Caracas (Venezuela, Bolivarian Republic of); Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616 (United States)

    2014-10-03

    Highlights: • Age-dependent increase in [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} in mdx cardiomyocytes. • Gadolinium significantly reduced both [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} at all ages. • IP{sub 3}-pathway inhibition reduced cations concentrations in dystrophic cardiomyocytes. - Abstract: Duchenne muscular dystrophy (DMD) is a lethal X-inherited disease caused by dystrophin deficiency. Besides the relatively well characterized skeletal muscle degenerative processes, DMD is also associated with a dilated cardiomyopathy that leads to progressive heart failure at the end of the second decade. The aim of the present study was to characterize the diastolic Ca{sup 2+} concentration ([Ca{sup 2+}]{sub d}) and diastolic Na{sup +} concentration ([Na{sup +}]{sub d}) abnormalities in cardiomyocytes isolated from 3-, 6-, 9-, and 12-month old mdx mice using ion-selective microelectrodes. In addition, the contributions of gadolinium (Gd{sup 3+})-sensitive Ca{sup 2+} entry and inositol triphosphate (IP{sub 3}) signaling pathways in abnormal [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} were investigated. Our results showed an age-dependent increase in both [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} in dystrophic cardiomyocytes compared to those isolated from age-matched wt mice. Gd{sup 3+} treatment significantly reduced both [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} at all ages. In addition, blockade of the IP{sub 3}-pathway with either U-73122 or xestospongin C significantly reduced ion concentrations in dystrophic cardiomyocytes. Co-treatment with U-73122 and Gd{sup 3+} normalized both [Ca{sup 2+}]{sub d} and [Na{sup +}]{sub d} at all ages in dystrophic cardiomyocytes. These data showed that loss of dystrophin in mdx cardiomyocytes produced an age-dependent intracellular Ca{sup 2+} and Na{sup +} overload mediated at least in part by enhanced Ca{sup 2+} entry through Gd{sup 3+} sensitive transient receptor potential channels (TRPC), and by IP{sub 3} receptors.

  15. Study of 40Ca-40Ca elastic scattering at intermediate energy

    International Nuclear Information System (INIS)

    Kumar, Ashok; Srivastava, B.B.

    1980-01-01

    The differential cross sections for 40 Ca- 40 Ca elastic scattering have been calculated at laboratory incident energy of 240 MeV using a sharp cut off of the partial waves below a critical angular momentum, 1sub(c)' to account for absorption. The effective 40 Ca- 40 Ca potential is taken to be the sum of a real nuclear potential and the Coulomb potential. The calculated differential cross sections which are in fair agreement with the experimental data are presented and discussed. (author)

  16. Crystal and magnetic study of the disordered perovskites Ca(Mn0.5Sb0.5)O3 and Ca(Fe0.5Sb0.5)O3

    International Nuclear Information System (INIS)

    Retuerto, M.; Martinez-Lope, M.J.; Garcia-Hernandez, M.; Munoz, A.; Fernandez-Diaz, M.T.; Alonso, J.A.

    2010-01-01

    We have investigated the double perovskites Ca 2 MSbO 6 (M = Mn, Fe) that have been prepared by solid-state reaction (M = Fe) and wet chemistry procedures (M = Mn). The crystal and magnetic structures have been studied from X-ray (XRD) and neutron powder diffraction (NPD) data. Rietveld refinements show that the crystal structures are orthorhombic (space group Pbnm) with complete disorder of M and Sb cations, so the formula should be rewritten as Ca(M 0.5 Sb 0.5 )O 3 . Due to this disorder no evidences of Jahn-Teller distortion can be observed in the MnO 6 octahedra of Ca(Mn 0.5 Sb 0.5 )O 3 , in contrast with the ordered double perovskite Sr 2 MnSbO 6 . Ca(Fe 0.5 Sb 0.5 )O 3 behaves as an antiferromagnet with an ordered magnetic moment for Fe 3+ of 1.53(4)μ B and a propagation vector k = 0, as investigated by low-temperature NPD. The antiferromagnetic ordering is a result of the high degree of Fe/Sb anti-site disorder of the sample, which originates the spontaneous formation of Fe-rich islands, characterized by the presence of strong Fe-O-Fe antiferromagnetic couplings with enough long-range coherence to produce a magnetic contribution perceptible by NPD. By contrast, the magnetic structure of Ca(Mn 0.5 Sb 0.5 )O 3 cannot be observed by low-temperature NPD because the magnitude of the ordered magnetic moments is below the detection threshold for neutrons.

  17. Ca2+-mediated generation of inositol 1,4,5-triphosphate and inositol 1,3,4,5-tetrakisphosphate in pancreatic islets. Studies with K+, glucose, and carbamylcholine

    International Nuclear Information System (INIS)

    Biden, T.J.; Peter-Riesch, B.; Schlegel, W.; Wollheim, C.B.

    1987-01-01

    The role of Ca2+ in the generation of inositol phosphates was investigated using rat pancreatic islets after steady state labeling with myo-[2- 3 H]inositol. Depolarizing K+ concentrations (24 mM) evoked early (2 s) increases in inositol 1,4,5-trisphosphate (Ins-1,4,5-P3) and inositol 1,3,4,5-tetrakisphosphate (Ins-1,3,4,5-P4) as measured by high performance anion-exchange chromatography. The increase in Ins-1,4,5-P3 was transient and was followed by a more pronounced rise in Ins-1,3,4-P3. These effects were dependent on the presence of extracellular Ca2+ but were not secondary to release of either neurotransmitters or metabolites of arachidonic acid. K+ also promoted the breakdown of phosphatidylinositol 4,5-bisphosphate (PtdIns-4,5-P2) and of the other phosphoinositides. Glucose (16.7 mM) was less marked in its effects but still promoted rapid increases in Ins-1,3,4,5-P4 (2 s) and Ins-1,4,5-P3 (10 s) and a slower rise in Ins-1,3,4-P3 (30 s). The levels of all three metabolites rose steadily over 10 min stimulation. These responses to glucose could be largely, although not entirely, inhibited by depletion of extracellular Ca2+ or by Ca2+ channel blockade with verapamil (20 microM). Carbamylcholine (0.5 mM) was the most potent stimulus used evoking early rises in Ins-1,4,5-P3 and Ins-1,3,4,5-P4 (2 s) followed by Ins-1,3,4-P3 (10 s), effects which were only partially dependent on extracellular Ca2+. The results suggest that a Ca2+-mediated PtdIns-4,5-P2 hydrolysis accounts for most of the Ins-1,4,5-P3 generated in response to glucose but not carbamylcholine

  18. MiR-124 suppresses cell proliferation in hepatocellular carcinoma by targeting PIK3CA

    International Nuclear Information System (INIS)

    Lang, Qingbo; Ling, Changquan

    2012-01-01

    Highlights: ► PIK3CA is a novel target of miR-124 in HepG2 cells. ► MiR-124 suppresses cell proliferation by downregulating PIK3CA expression. ► MiR-124 regulates the PI3K/Akt pathway in HepG2 cells. ► MiR-124 overexpression inhibits the tumorigenesis in nude mice. -- Abstract: MicroRNAs (miRNAs) have crucial roles in the development and progression of human cancers, including hepatocellular carcinoma (HCC). Recent studies have shown that microRNA-124 (miR-124) was downregulated in HCC; however, the underlying mechanisms by which miR-124 suppresses tumorigenesis in HCC are largely unknown. In this study, we report that phosphoinositide 3-kinase catalytic subunit alpha (PIK3CA) is a novel target of miR-124 in HepG2 cells. Overexpression of miR-124 resulted in decreased expression of PIK3CA at both mRNA and protein levels. We found that miR-124 overexpression markedly suppressed cell proliferation by inducing G1-phase cell-cycle arrest in vitro. Consistent with the restoring miR-124 expression, PIK3CA knockdown suppressed cell proliferation, whereas overexpression of PIK3CA abolished the suppressive effect of miR-124. Mechanistic studies showed that miR-124-mediated reduction of PIK3CA resulted in suppression of PI3K/Akt pathway. The expressions of Akt and mTOR, key components of the PI3K/Akt pathway, were all downregulated. Moreover, we found overexpressed miR-124 effectively repressed tumor growth in xenograft animal experiments. Taken together, our results demonstrate that miR-124 functions as a growth-suppressive miRNA and plays an important role in inhibiting the tumorigenesis through targeting PIK3CA.

  19. MiR-124 suppresses cell proliferation in hepatocellular carcinoma by targeting PIK3CA

    Energy Technology Data Exchange (ETDEWEB)

    Lang, Qingbo [Department of Traditional Chinese Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China); Ling, Changquan, E-mail: lingchangquan@hotmail.com [Department of Traditional Chinese Medicine, Changhai Hospital, Second Military Medical University, Shanghai 200433 (China)

    2012-09-21

    Highlights: Black-Right-Pointing-Pointer PIK3CA is a novel target of miR-124 in HepG2 cells. Black-Right-Pointing-Pointer MiR-124 suppresses cell proliferation by downregulating PIK3CA expression. Black-Right-Pointing-Pointer MiR-124 regulates the PI3K/Akt pathway in HepG2 cells. Black-Right-Pointing-Pointer MiR-124 overexpression inhibits the tumorigenesis in nude mice. -- Abstract: MicroRNAs (miRNAs) have crucial roles in the development and progression of human cancers, including hepatocellular carcinoma (HCC). Recent studies have shown that microRNA-124 (miR-124) was downregulated in HCC; however, the underlying mechanisms by which miR-124 suppresses tumorigenesis in HCC are largely unknown. In this study, we report that phosphoinositide 3-kinase catalytic subunit alpha (PIK3CA) is a novel target of miR-124 in HepG2 cells. Overexpression of miR-124 resulted in decreased expression of PIK3CA at both mRNA and protein levels. We found that miR-124 overexpression markedly suppressed cell proliferation by inducing G1-phase cell-cycle arrest in vitro. Consistent with the restoring miR-124 expression, PIK3CA knockdown suppressed cell proliferation, whereas overexpression of PIK3CA abolished the suppressive effect of miR-124. Mechanistic studies showed that miR-124-mediated reduction of PIK3CA resulted in suppression of PI3K/Akt pathway. The expressions of Akt and mTOR, key components of the PI3K/Akt pathway, were all downregulated. Moreover, we found overexpressed miR-124 effectively repressed tumor growth in xenograft animal experiments. Taken together, our results demonstrate that miR-124 functions as a growth-suppressive miRNA and plays an important role in inhibiting the tumorigenesis through targeting PIK3CA.

  20. Long afterglow property of Er"3"+ doped Ca_2SnO_4 phosphor

    International Nuclear Information System (INIS)

    Zhang, Dongyun; Shi, Mingming; Sun, Yiwen; Guo, Yunyun; Chang, Chengkang

    2016-01-01

    A novel green emitting long afterglow phosphor, Er"3"+ -doped Ca_2SnO_4 (Ca_2SnO_4:Er"3"+), was prepared successfully via a traditional high temperature solid–state reaction method. Its properties have been characterized and analyzed by utilizing x-ray diffraction (XRD), photoluminescence spectroscope (PLS), afterglow decay curve (ADC) and thermal luminescence spectroscope (TLS). Three main emission peaks of PLS locate at 524, 550 and 668 nm, corresponding to CIE chromaticity coordinates of x = 0.326, y = 0.6592. An optimal doping concentration of Er"3"+ of 2% was determined. The Ca_2SnO_4:Er"3"+ phosphors showed a typical triple-exponential afterglow decay behavior when the UV source was switched off. Thermal simulated luminescence study indicated that the persistent afterglow of Ca_2SnO_4:2 mol% Er"3"+ phosphors was generated by the suitable electron or hole traps which were resulted from the doping the Ca_2SnO_4 host with rare-earth ions (Er"3"+). - Highlights: • A novel green emitting long afterglow phosphor, Ca_2SnO_4:Er"3"+, was prepared. • An optimal doping concentration of Er"3"+ of 2% was determined. • After the UV source was turned off, the Ca_2SnO_4:Er"3"+ showed a typical triple-exponential afterglow decay behavior. • CIE chromaticity coordinates results confirmed a green light emitting of the Ca_2SnO_4:Er"3"+. • The persistent afterglow of the Ca_2SnO_4:Er"3"+ was attributed to suitable electron or hole traps.

  1. STIM1 as a key regulator for Ca2+ homeostasis in skeletal-muscle development and function

    Directory of Open Access Journals (Sweden)

    Kiviluoto Santeri

    2011-04-01

    Full Text Available Abstract Stromal interaction molecules (STIM were identified as the endoplasmic-reticulum (ER Ca2+ sensor controlling store-operated Ca2+ entry (SOCE and Ca2+-release-activated Ca2+ (CRAC channels in non-excitable cells. STIM proteins target Orai1-3, tetrameric Ca2+-permeable channels in the plasma membrane. Structure-function analysis revealed the molecular determinants and the key steps in the activation process of Orai by STIM. Recently, STIM1 was found to be expressed at high levels in skeletal muscle controlling muscle function and properties. Novel STIM targets besides Orai channels are emerging. Here, we will focus on the role of STIM1 in skeletal-muscle structure, development and function. The molecular mechanism underpinning skeletal-muscle physiology points toward an essential role for STIM1-controlled SOCE to drive Ca2+/calcineurin/nuclear factor of activated T cells (NFAT-dependent morphogenetic remodeling programs and to support adequate sarcoplasmic-reticulum (SR Ca2+-store filling. Also in our hands, STIM1 is transiently up-regulated during the initial phase of in vitro myogenesis of C2C12 cells. The molecular targets of STIM1 in these cells likely involve Orai channels and canonical transient receptor potential (TRPC channels TRPC1 and TRPC3. The fast kinetics of SOCE activation in skeletal muscle seem to depend on the triad-junction formation, favoring a pre-localization and/or pre-formation of STIM1-protein complexes with the plasma-membrane Ca2+-influx channels. Moreover, Orai1-mediated Ca2+ influx seems to be essential for controlling the resting Ca2+ concentration and for proper SR Ca2+ filling. Hence, Ca2+ influx through STIM1-dependent activation of SOCE from the T-tubule system may recycle extracellular Ca2+ losses during muscle stimulation, thereby maintaining proper filling of the SR Ca2+ stores and muscle function. Importantly, mouse models for dystrophic pathologies, like Duchenne muscular dystrophy, point towards an

  2. Cloning and expression analysis of CaPIP1-1 gene in pepper (Capsicum annuum L.).

    Science.gov (United States)

    Yin, Yan-Xu; Wang, Shu-Bin; Zhang, Huai-Xia; Xiao, Huai-Juan; Jin, Jing-Hao; Ji, Jiao-Jiao; Jing, Hua; Chen, Ru-Gang; Arisha, Mohamed Hamed; Gong, Zhen-Hui

    2015-05-25

    Plant aquaporins are responsible for water transmembrane transport, which play an important role on abiotic and biotic stresses. A novel plasma membrane intrinsic protein of CaPIP1-1 was isolated from the pepper P70 according to transcriptome databases of Phytophthora capsici inoculation and chilling stress library. CaPIP1-1, which is 1155 bp in length with an open reading frame of 861 bp, encoded 286 amino acids. Three introns, exhibited CT/AC splice junctions, were observed in CaPIP1-1. The numbers and location of introns in CaPIP1-1 were the same as observed in tomato and potato. CaPIP1-1 was abundantly expressed in pepper fruit. Increased transcription levels of CaPIP1-1 were found in the different stresses, including chilling stress, salt stress, mannitol stress, salicylic acid, ABA treatment and Phytophthora capsici infection. The expression of CaPIP1-1 was downregulated by 50 μM HgCl2 and 100 μM fluridone. The pepper plants silenced CaPIP1-1 in cv. Qiemen showed growth inhibition and decreased tolerance to salt and mannitol stresses using detached leaf method. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Structure and electrical conduction of the system La sub(1-x)Ca sub(x)FeO sub(3-α)

    International Nuclear Information System (INIS)

    Hombo, Jukichi; Urabe, Noriake; Hiroshige, Gota; Hamada, Kotaro.

    1982-01-01

    Perovskite phases in the system, La sub(1-x)Ca sub(x)FeO sub(3-α) were prepared with La 2 O 3 , CaCO 3 , and Fe 2 O 3 by firing in air and in vacuo. The compositions of samples fired in vacuo and in air are represented as La sub(1-x)Ca sub(x)FeO sub(3-x 2) and La sub(1-x)Ca sub(x)Fe sub(1-y)sup(3+)Fe sub(y)sup(4+)O sub(3-x/2+y/2), respectively. That is, samples fired in vacuo contain some oxygen vacancies and no tetravalent iron; in contrast, samples fired in air contain both oxygen vacancies and tetravalent iron in the structures. The electrical conductivities of these synthesized oxides depended extensively upon the content of tetravalent iron. For instance, the conductivity of the sample x = 0.6 fired in air was larger by 10 6 than that of the sample fired in vacuo. In this system, except for the two terminal compositions of x = 0 and x = 1.0, the values of activation energy for conduction are considerably small, and from the results of thermo-electromotive force measurement, the charge carrier was positive. Furthermore, the conductivity increased somewhat with time during the conductivity measurement by the direct-current method. These facts suggest that the electrical conducted would not be ionic but electronic. The electrical conduction would then be carried out by the so-called hopping mechanism by which the positive charge is transferred. (author)

  4. EDF-1 downregulates the CaM/Cn/NFAT signaling pathway during adipogenesis

    International Nuclear Information System (INIS)

    López-Victorio, Carlos J.; Velez-delValle, Cristina; Beltrán-Langarica, Alicia; Kuri-Harcuch, Walid

    2013-01-01

    Highlights: ► EDF-1 participates early adipogenesis in 3T3F442A cells induced with Staurosporine/Dexamethasone. ► EDF-1 associates with CaM and Cn, most likely inactivating Cn. ► EDF-1/CaM complex seems to prevent NFATc1 activation by Cn. ► EDF-1 regulates the Cn/CaM/NFATc1 pathway during adipogenesis. ► EDF-1 may regulate the activation of Cn through a complex formation with CaM. - Abstract: The endothelial differentiation factor-1 (EDF-1) is a calmodulin binding protein that regulates calmodulin-dependent enzymes. In endothelial cells, this factor can form a protein complex with calmodulin. We analyzed the relationship between this factor and the members of calmodulin/calcineurin/nuclear factor of activated T-cells (NFAT) signaling pathway during adipogenesis of 3T3-F442A cells. We found that the expression of edf1 is upregulated during early adipogenesis, whereas that of calcineurin gene is lowered, suggesting that this pathway should be downregulated to allow for adipogenesis to occur. We also found that EDF-1 associates with calmodulin and calcineurin, most likely inactivating calcineurin. Our results showed that EDF-1 inactivates the calmodulin/calcineurin/NFAT pathway via sequestration of calmodulin, during early adipogenesis, and we propose a mechanism that negatively regulates the activation of calcineurin through a complex formation between EDF-1 and calmodulin. This finding raises the possibility that modulating this pathway might offer some alternatives to regulate adipose biology

  5. EDF-1 downregulates the CaM/Cn/NFAT signaling pathway during adipogenesis

    Energy Technology Data Exchange (ETDEWEB)

    López-Victorio, Carlos J.; Velez-delValle, Cristina; Beltrán-Langarica, Alicia [Department of Cell Biology, Center for Research and Advanced Studies-IPN, Apdo. Postal 14-740, México City 07000 (Mexico); Kuri-Harcuch, Walid, E-mail: walidkuri@gmail.com [Department of Cell Biology, Center for Research and Advanced Studies-IPN, Apdo. Postal 14-740, México City 07000 (Mexico)

    2013-03-01

    Highlights: ► EDF-1 participates early adipogenesis in 3T3F442A cells induced with Staurosporine/Dexamethasone. ► EDF-1 associates with CaM and Cn, most likely inactivating Cn. ► EDF-1/CaM complex seems to prevent NFATc1 activation by Cn. ► EDF-1 regulates the Cn/CaM/NFATc1 pathway during adipogenesis. ► EDF-1 may regulate the activation of Cn through a complex formation with CaM. - Abstract: The endothelial differentiation factor-1 (EDF-1) is a calmodulin binding protein that regulates calmodulin-dependent enzymes. In endothelial cells, this factor can form a protein complex with calmodulin. We analyzed the relationship between this factor and the members of calmodulin/calcineurin/nuclear factor of activated T-cells (NFAT) signaling pathway during adipogenesis of 3T3-F442A cells. We found that the expression of edf1 is upregulated during early adipogenesis, whereas that of calcineurin gene is lowered, suggesting that this pathway should be downregulated to allow for adipogenesis to occur. We also found that EDF-1 associates with calmodulin and calcineurin, most likely inactivating calcineurin. Our results showed that EDF-1 inactivates the calmodulin/calcineurin/NFAT pathway via sequestration of calmodulin, during early adipogenesis, and we propose a mechanism that negatively regulates the activation of calcineurin through a complex formation between EDF-1 and calmodulin. This finding raises the possibility that modulating this pathway might offer some alternatives to regulate adipose biology.

  6. Crystal structure and physical properties of new Ca{sub 2}TGe{sub 3} (T = Pd and Pt) germanides

    Energy Technology Data Exchange (ETDEWEB)

    Klimczuk, T., E-mail: tomasz.klimczuk@pg.gda.pl [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80–233 Gdansk (Poland); Xie, Weiwei [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States); Winiarski, M.J.; Kozioł, R.; Litzbarski, L.S. [Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80–233 Gdansk (Poland); Luo, Huixia; Cava, R.J. [Department of Chemistry, Princeton University, Princeton, NJ 08544 (United States)

    2016-11-15

    The crystallographic, electronic transport and thermal properties of Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3} are reported. The compounds crystalize in an ordered variant of the AlB{sub 2} crystal structure, in space group P6/mmm, with the lattice parameters a = 8.4876(4) Å/8.4503(5) Å and c = 4.1911(3) Å/4.2302(3) Å for Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3}, respectively. The resistivity data exhibit metallic behavior with residual-resistivity-ratios (RRR) of 13 for Ca{sub 2}PdGe{sub 3} and 6.5 for Ca{sub 2}PtGe{sub 3}. No superconducting transition is observed down to 0.4 K. Specific heat studies reveal similar values of the Debye temperatures and Sommerfeld coefficients: Θ{sub D} = 298 K, γ = 4.1 mJ mol{sup −1} K{sup −2} and Θ{sub D} = 305 K, γ = 3.2 mJ mol{sup −1} K{sup −2} for Ca{sub 2}PdGe{sub 3} and Ca{sub 2}PtGe{sub 3}, respectively. The low value of γ is in agreement with the electronic structure calculations.

  7. Comparative study of perovskite Pr_(_1_-_x_)Ca_xCoO_3 e Gd_(_1_-_x_)Ca_xCoO_3 (x=0,2) synthesized by gelatin modified route for application in automotive catalysis

    International Nuclear Information System (INIS)

    Araujo, E.M. de; Medeiros, M.R.A.; Paiva, A.K.O.; Borges, F.M.M.; Ruiz, J.A.C.

    2016-01-01

    Increased air pollution intensified the search for materials that could convert pollutant gases into less harmful substances. Thus, mixed oxides with perovskite structure began to be developed for presenting important features for the automotive catalysis. In this study has been compared the chemical composition of the materials with Pr_(_1_-_x_)Ca_xCoO_3 and Gd_(_1_-_x_)Ca_xCoO_3 (x = 0.2) synthesized by the method gelatine. The samples were characterized by techniques: Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-Ray Diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence (XRF) and subjected to the catalytic test in methane combustion reaction. The evaluation of the catalytic activity showed that gadolinium catalyst is more efficient compared with the praseodymium catalyst, although they have similar maximum conversion of methane at high temperature, during the catalytic test the material with gadolinium showed higher catalytic activity and stability. (author)

  8. In-situ thermal analysis and macroscopical characterization of Mg-xCa and Mg-0.5Ca-xZn alloy systems

    Energy Technology Data Exchange (ETDEWEB)

    Farahany, Saeed [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Bakhsheshi-Rad, Hamid Reza, E-mail: Rezabakhsheshi@gmail.com [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Idris, Mohd Hasbullah [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq [Medical Implants Technology Group, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Department of Biomechanics and Biomedical Materials, Faculty of Biomedical Engineering and Health Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Lotfabadi, Amir Fereidouni [Department of Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Ourdjini, Ali [Department of Materials Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer The effect of Ca and Zn addition on Mg-Ca and Mg-Ca-Zn were investigated. Black-Right-Pointing-Pointer Ca and Zn addition decreased solid fraction at coherency point. Black-Right-Pointing-Pointer T{sub N}-T{sub DCP} increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn, respectively. Black-Right-Pointing-Pointer Three reactions were detected when Zn/Ca atomic ratio less than 1.25 in Mg-Ca-Zn. Black-Right-Pointing-Pointer A new peak Mg{sub 51}Zn{sub 20} was identified in Mg-0.5Ca-9Zn in addition of other peaks. - Abstract: This research described the identification phases by thermal analysis and microscopy inspection of Mg-xCa and Mg-0.5%Ca-xZn alloys that were solidified at slow cooling rate. Analysis of cooling curve after Ca addition shows the evolution of the Mg{sub 2}Ca intermetallic phase at around 520 Degree-Sign C in addition to {alpha}-Mg phase. First derivative curves of alloys after the addition of Zn to Mg-0.5Ca alloy reveals three peaks related to {alpha}-Mg, Mg{sub 2}Ca and Ca{sub 2}Mg{sub 6}Zn{sub 3} for alloys that have Zn/Ca atomic ratio less than 1.23. The peak of Mg{sub 2}Ca reaction on the first derivative curves disappeared for alloys containing Zn/Ca ratio more than 1.23. A new peak was also observed at 330 Degree-Sign C for Mg-0.5Ca-9Zn which was identified as Mg{sub 51}Zn{sub 20}. Solid fraction at coherency point decreased with increasing Ca and Zn elements. However, coherency time and difference between the nucleation and coherency temperatures (T{sub N}-T{sub DCP}) increased by adding Ca and Zn in Mg-Ca and Mg-Ca-Zn systems.

  9. F-actin-based Ca signaling-a critical comparison with the current concept of Ca signaling.

    Science.gov (United States)

    Lange, Klaus; Gartzke, Joachim

    2006-11-01

    A short comparative survey on the current idea of Ca signaling and the alternative concept of F-actin-based Ca signaling is given. The two hypotheses differ in one central aspect, the mechanism of Ca storage. The current theory rests on the assumption of Ca-accumulating endoplasmic/sarcoplasmic reticulum-derived vesicles equipped with an ATP-dependent Ca pump and IP3- or ryanodine-sensitive channel-receptors for Ca-release. The alternative hypothesis proceeds from the idea of Ca storage at the high-affinity binding sites of actin filaments. Cellular sites of F-actin-based Ca storage are microvilli and the submembrane cytoskeleton. Several specific features of Ca signaling such as store-channel coupling, quantal Ca release, spiking and oscillations, biphasic and "phasic" uptake kinetics, and Ca-induced Ca release (CICR), which are not adequately described by the current concept, are inherent properties of the F-actin system and its dynamic state of treadmilling. Copyright 2006 Wiley-Liss, Inc.

  10. New High Pressure Phase of CaCO3: Implication for the Deep Diamond Formation

    Science.gov (United States)

    Mao, Z.; Li, X.; Zhang, Z.; Lin, J. F.; Ni, H.; Prakapenka, V.

    2017-12-01

    Surface carbon can be transported to the Earth's deep interior through sinking subduction slabs. Carbonates, including CaCO3, MgCO3 and MgCa(CO3)2, are important carbon carriers for the deep carbon cycle. Experimental studies on the phase stability of carbonates with coexisting mantle minerals at relevant pressure and temperature conditions are thus important for understanding the deep carbon cycle. In particular, recent petrological studies have revealed the evidence for the transportation of CaCO3 to the depth at least of the top lower mantle by analyzing the diamond inclusions. Yet the phase stability of CaCO3 at relevant pressure and temperature conditions of the top lower mantle is still unclear. Previous single-crystal study has shown that CaCO3 transforms from the CaCO3-III structure to CaCO3-VI at 15 GPa and 300 K. The CaCO3-VI is stable at least up to 40 GPa at 300 K. At high temperatures, CaCO3 in the aragonite structure will directly transform into the post-aragonite structure at 40 GPa. However, a recent theoretical study predicted a new phase of CaCO3 with a space group of P21/c between 32 and 48 GPa which is different from previous experimental results. In this study, we have investigated the phase stability of CaCO3 at high pressure-temperature conditions using synchrotron X-ray diffraction in laser-heated diamond anvil cells. We report the discovery of a new phase of CaCO3 at relevant pressure-temperature conditions of the top lower mantle which is consistent with previous theoretical predictions. This new phase is an important carrier for the transportation of carbon to the Earth's lower mantle and crucial for growing deep diamonds in the region.

  11. Decreased store operated Ca2+ entry in dendritic cells isolated from mice expressing PKB/SGK-resistant GSK3.

    Science.gov (United States)

    Schmid, Evi; Yan, Jing; Nurbaeva, Meerim K; Russo, Antonella; Yang, Wenting; Faggio, Caterina; Shumilina, Ekaterina; Lang, Florian

    2014-01-01

    Dendritic cells (DCs), key players of immunity, are regulated by glycogen synthase kinase GSK3. GSK3 activity is suppressed by PKB/Akt and SGK isoforms, which are in turn stimulated by the PI3K pathway. Exposure to bacterial lipopolysaccharides increases cytosolic Ca(2+)-concentration ([Ca(2+)]i), an effect augmented in DCs isolated from mutant mice expressing PKB/SGK-resistant GSK3α,β (gsk3(KI) ). Factors affecting [Ca(2+)]i include Ca(2+)-release from intracellular stores (CRIS), store-operated Ca(2+)-entry (SOCE) through STIM1/STIM2-regulated Orai1, K(+)-dependent Na(+)/Ca(2+)-exchangers (NCKX), K(+)-independent Na(+)/Ca(2+)-exchangers (NCX) and calbindin-D28k. The present study explored whether PKB/SGK-dependent GSK3α, β-activity impacts on CRIS, SOCE, NCKX, NCX or calbindin. DCs were isolated from gsk3(KI) mice and respective wild-type mice (gsk3(WT) ), [Ca(2+)]i estimated from Fura2 fluorescence, Orai1, STIM1, STIM2 as well as calbindin-D28k protein abundance determined by Western blotting and mRNA levels quantified by real time PCR. As a result, thapsigargin-induced CRIS and SOCE were significantly blunted by GSK3-inhibitors SB216763 (1-10 µM, 30 min) or GSK-XIII (10 µM, 30 min) but were significantly lower in gsk3(WT) than in gsk3(KI) DCs. Orai1, STIM1 and STIM2 protein abundance was significantly lower and calbindin-D28k abundance significantly higher in gsk3(KI) than in gsk3(WT) DCs. Activity of NCKX and NCX was significantly higher in gsk3(KI) than in gsk3(WT) DCs and was significantly increased by SB216763 (1 µM, 30 min) or GSK-XIII (10 µM, 30 min). Treatment of gsk3(WT) DCs with SB216763 (1 µM, 4-24 h) or GSK-XIII (10 µM, 4-24 h) did not significantly modify the protein abundance of Orai1, STIM1 and STIM2. The present observations point to a dual role of GSK3 in the regulation of Ca(2+) in DCs. Acute inhibition of GSK3 blunted the increase of [Ca(2+)]i following CRIS and SOCE and stimulated NCKX/NCX activity. However, expression of PKB

  12. Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas

    International Nuclear Information System (INIS)

    Murat, C.B.; Braga, P.B.S.; Fortes, M.A.H.Z.; Bronstein, M.D.; Corrêa-Giannella, M.L.C.; Giorgi, R.R.

    2012-01-01

    The tumorigenesis of pituitary adenomas is poorly understood. Mutations of the PIK3CA proto-oncogene, which encodes the p110-α catalytic subunit of PI3K, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the PI3K/Akt signaling pathway. Only one Chinese study described somatic mutations and amplification of the PIK3CA gene in a large series of pituitary adenomas. The aim of the present study was to determine genetic alterations of PIK3CA in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry: 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. Direct sequencing of exons 9 and 20 assessed by qPCR was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. Previously identified PIK3CA mutations (exon 20) were detected in four cases (12.1%). Interestingly, the Chinese study reported mutations only in invasive tumors, while we found a PIK3CA mutation in one noninvasive corticotroph microadenoma. PIK3CA amplification was observed in 21.2% (7/33) of the cases. This study demonstrates the presence of somatic mutations and amplifications of the PIK3CA gene in a second series of pituitary adenomas, corroborating the previously described involvement of the PI3K/Akt signaling pathway in the tumorigenic process of this gland

  13. Mutation and genomic amplification of the PIK3CA proto-oncogene in pituitary adenomas

    Energy Technology Data Exchange (ETDEWEB)

    Murat, C.B.; Braga, P.B.S.; Fortes, M.A.H.Z. [Laboratório de Endocrinologia Celular e Molecular (LIM-25), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Bronstein, M.D. [Unidade de Neuroendocrinologia, Serviço de Endocrinologia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil); Corrêa-Giannella, M.L.C.; Giorgi, R.R. [Laboratório de Endocrinologia Celular e Molecular (LIM-25), Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2012-07-13

    The tumorigenesis of pituitary adenomas is poorly understood. Mutations of the PIK3CA proto-oncogene, which encodes the p110-α catalytic subunit of PI3K, have been reported in various types of human cancers regarding the role of the gene in cell proliferation and survival through activation of the PI3K/Akt signaling pathway. Only one Chinese study described somatic mutations and amplification of the PIK3CA gene in a large series of pituitary adenomas. The aim of the present study was to determine genetic alterations of PIK3CA in a second series that consisted of 33 pituitary adenomas of different subtypes diagnosed by immunohistochemistry: 6 adrenocorticotropic hormone-secreting microadenomas, 5 growth hormone-secreting macroadenomas, 7 prolactin-secreting macroadenomas, and 15 nonfunctioning macroadenomas. Direct sequencing of exons 9 and 20 assessed by qPCR was employed to investigate the presence of mutations and genomic amplification defined as a copy number ≥4. Previously identified PIK3CA mutations (exon 20) were detected in four cases (12.1%). Interestingly, the Chinese study reported mutations only in invasive tumors, while we found a PIK3CA mutation in one noninvasive corticotroph microadenoma. PIK3CA amplification was observed in 21.2% (7/33) of the cases. This study demonstrates the presence of somatic mutations and amplifications of the PIK3CA gene in a second series of pituitary adenomas, corroborating the previously described involvement of the PI3K/Akt signaling pathway in the tumorigenic process of this gland.

  14. PIK3CA expression in diffuse large B cell lymphoma tissue and the effect of its knockdown in vitro

    Directory of Open Access Journals (Sweden)

    Cui W

    2017-04-01

    Full Text Available Wenli Cui,1–4,* Shutao Zheng,5,6,* Zebing Liu,13 Weige Wang,13 Ying Cai,13 Rui Bi,13 Bing Cao,13 Xiaoyan Zhou13 1Department of Pathology, Shanghai Cancer Center, Fudan University, 2Department of Oncology, Shanghai Medical College, Fudan University, 3Institute of Pathology, Fudan University, Shanghai, 4Department of Pathology, The First Affiliated Hospital of Xinjiang Medical University, 5Clinical Medical Research Institute, First Affiliated Hospital of Xinjiang Medical University, 6State Key Lab Incubation Base of Xinjiang Major Diseases Research, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, People’s Republic of China *These authors contributed equally to this work Abstract: PIK3CA has been extensively investigated from its molecular mechanism perspective and epidemiological association with its mutations in different types of cancers. However, little has been reported regarding the clinicopathological significance of PIK3CA expression in diffuse large B cell lymphoma (DLBCL. In the present study, we investigated the clinicopathological significance of PIK3CA in DLBCL by performing immunohistochemical evaluation of PIK3CA in tissue microarrays consisting of 199 cases of DLBCL. Kaplan–Meier survival analysis was performed to analyze the association between PIK3CA expression and overall prognosis. To further investigate the role of PIK3CA mediated in the proliferation, cell cycle and apoptosis of DLBCL cells, Cell Counting Kit-8 (CCK-8 and flow cytometry assays were carried out in DLBCL cell lines after successful, stable knockdown of PIK3CA using lentiviral short hairpin RNA inference. Our results indicated that although PIK3CA was shown to be extensively expressed in DLBCL, no significant association was observed between PIK3CA expression and clinical outcome or between PIK3CA expression and other clinicopathological parameters, except between performance state (PS

  15. Novel electrical conductivity properties in Ca-doped BiFeO{sub 3} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Wang, S. Y., E-mail: shouyu.wang@yahoo.com [Tianjin Normal University, College of Physics and Materials Science (China); Liu, W. F., E-mail: wfliu@tju.edu.cn [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Xi, X. J. [Tianjin Normal University, College of Physics and Materials Science (China); Zhang, H. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Guo, F. [Tianjin Normal University, College of Physics and Materials Science (China); Xu, X. L. [Tianjin University, Department of Applied Physics, Institute of Advanced Materials Physics, Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science (China); Li, M.; Liu, L.; Zhang, C.; Li, X.; Yang, J. B. [Tianjin Normal University, College of Physics and Materials Science (China)

    2015-05-15

    The charge defective structure in Bi{sub 1−x}Ca{sub x}FeO{sub 3} (CBFO, x = 0, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3) nanoparticles (NPs) ranging from 140 to 25 nm as well as their relations to band gap and leakage current behavior are investigated. It is demonstrated that Ca doping effectively narrows the band gap from ∼2.16 to ∼2.02 eV, due to the appearance and accumulation of oxygen vacancy. Subsequently, enhanced electrical conductivity was obtained in these CBFO NPs, which leads to the appearance of a distinct threshold switching behavior in Ca-doped BFO NPs with higher conductivity at room temperature. Possible mechanisms for Ca doping effects on the electric conduction were discussed upon the interplay of NPs’ size effect and mobile charged defects on the basis of reduced particle size and the increased density of oxygen vacancy analyzed through X-ray photoelectron spectrum.

  16. Structure of the CaMKIIdelta/calmodulin complex reveals the molecular mechanism of CaMKII kinase activation.

    Directory of Open Access Journals (Sweden)

    Peter Rellos

    2010-07-01

    Full Text Available Long-term potentiation (LTP, a long-lasting enhancement in communication between neurons, is considered to be the major cellular mechanism underlying learning and memory. LTP triggers high-frequency calcium pulses that result in the activation of Calcium/Calmodulin (CaM-dependent kinase II (CaMKII. CaMKII acts as a molecular switch because it remains active for a long time after the return to basal calcium levels, which is a unique property required for CaMKII function. Here we describe the crystal structure of the human CaMKIIdelta/Ca2+/CaM complex, structures of all four human CaMKII catalytic domains in their autoinhibited states, as well as structures of human CaMKII oligomerization domains in their tetradecameric and physiological dodecameric states. All four autoinhibited human CaMKIIs were monomeric in the determined crystal structures but associated weakly in solution. In the CaMKIIdelta/Ca2+/CaM complex, the inhibitory region adopted an extended conformation and interacted with an adjacent catalytic domain positioning T287 into the active site of the interacting protomer. Comparisons with autoinhibited CaMKII structures showed that binding of calmodulin leads to the rearrangement of residues in the active site to a conformation suitable for ATP binding and to the closure of the binding groove for the autoinhibitory helix by helix alphaD. The structural data, together with biophysical interaction studies, reveals the mechanism of CaMKII activation by calmodulin and explains many of the unique regulatory properties of these two essential signaling molecules.This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3-D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the Web plugin are available in Text S1.

  17. Interrelation between domain structures and polarization switching in hybrid improper ferroelectric Ca3(Mn,Ti)2O7

    Science.gov (United States)

    Gao, Bin; Huang, Fei-Ting; Wang, Yazhong; Kim, Jae-Wook; Wang, Lihai; Lim, Seong-Joon; Cheong, Sang-Wook

    2017-05-01

    Ca3Mn2O7 and Ca3Ti2O7 have been proposed as the prototypical hybrid improper ferroelectrics (HIFs), and a significant magnetoelectric (ME) coupling in magnetic Ca3Mn2O7 is, in fact, reported theoretically and experimentally. Although the switchability of polarization is confirmed in Ca3Ti2O7 and other non-magnetic HIFs, there is no report of switchable polarization in the isostructural Ca3Mn2O7. We constructed the phase diagram of Ca3Mn2-xTixO7 through our systematic study of a series of single crystalline Ca3Mn2-xTixO7 (x = 0, 0.1, 1, 1.5, and 2). Using transmission electron microscopy, we have unveiled the unique domain structure of Ca3Mn2O7: the high-density 90° stacking of a- and b-domains along the c-axis due to the phase transition through an intermediate Acca phase and the in-plane irregular wavy ferroelastic twin domains. The interrelation between domain structures and physical properties is unprecedented: the stacking along the c-axis prevents the switching of polarization and causes the irregular in-plane ferroelastic domain pattern. In addition, we have determined the magnetic phase diagram and found complex magnetism of Ca3Mn2O7 with isotropic canted moments. These results lead to negligible observable ME coupling in Ca3Mn2O7 and guide us to explore multiferroics with large ME coupling.

  18. Heterogeneous microchemistry between CdSO4 and CaCO3 particles under humidity and liquid water

    International Nuclear Information System (INIS)

    Falgayrac, Guillaume; Sobanska, Sophie; Brémard, Claude

    2013-01-01

    Highlights: ► Raman analysis of chemical reactions between CdSO 4 and CaCO 3 particles. ► Under humid air no changes of morphology and chemical composition were observed. ► Condensation of liquid water generates an insoluble CdCO 3 layer on CaCO 3 surface. ► Addition of water previously equilibrated with CaCO 3 generates CdCO 3 and CaSO 4 . -- Abstract: Laboratory experiments using in situ Raman imaging combined with ex situ TOF-S-SIMS demonstrate the behavior of CdSO 4 ·8/3H 2 O microparticles in contact with {101 ¯ 4} CaCO 3 (calcite) surface under three different experimental conditions representative of unpolluted atmosphere. The contact of CdSO 4 ·8/3H 2 O particles with CaCO 3 surface in humid air (RH ∼ 40–80%) does not induce any chemical reaction. In contrast, the condensation of a water drop on CdSO 4 ·8/3H 2 O/CaCO 3 interface causes the free dissolution of CdSO 4 ·8/3H 2 O particle in the drop. A CdSO 4 ·8/3H 2 O microcrystal is reformed after gentle drying with a CdSO 4 ·H 2 O coating of the CaCO 3 surface. The TOF-S-SIMS image of the CaCO 3 surface provides evidence of a thin layer corresponding probably to insoluble coating of CdCO 3 (otavite) or Cd x Ca 1−x CO 3 solid solution at the liquid–solid interface. This layer armours the CaCO 3 from further dissolution and stops the reaction. The deposition of CdSO 4 ·8/3H 2 O particle in water drop previously in contact with CaCO 3 for a long time generates CdCO 3 small rhombohedral crystals while gentle drying provokes the crystallization of bar shape crystals of CaSO 4 ·2H 2 O (gypsum). These laboratory results provide valuable chemical prediction for a possible fate of cadmium rich particles emitted in the atmosphere and thus, can contribute to realistic assessment of human exposure to Cd hazard

  19. An integrative genomic and proteomic analysis of PIK3CA, PTEN and AKT mutations in breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Stemke-Hale, Katherine; Gonzalez-Angulo, Ana Maria; Lluch, Ana; Neve, Richard M.; Kuo, Wen-Lin; Davies, Michael; Carey, Mark; Hu, Zhi; Guan, Yinghui; Sahin, Aysegul; Symmans, W. Fraser; Pusztai, Lajos; Nolden, Laura K.; Horlings, Hugo; Berns, Katrien; Hung, Mien-Chie; van de Vijver, Marc J.; Valero, Vicente; Gray, Joe W.; Bernards, Rene; Mills, Gordon B.; Hennessy, Bryan T.

    2008-05-06

    Phosphatidylinositol-3-kinase (PI3K)/AKT pathway aberrations are common in cancer. By applying mass spectroscopy-based sequencing and reverse phase protein arrays to 547 human breast cancers and 41 cell lines, we determined the subtype specificity and signaling effects of PIK3CA, AKT and PTEN mutations, and the effects of PIK3CA mutations on responsiveness to PI3K inhibition in-vitro and on outcome after adjuvant tamoxifen. PIK3CA mutations were more common in hormone receptor positive (33.8%) and HER2-positive (24.6%) than in basal-like tumors (8.3%). AKT1 (1.4%) and PTEN (2.3%) mutations were restricted to hormone receptor-positive cancers with PTEN protein levels also being significantly lower in hormone receptor-positive cancers. Unlike AKT1 mutations, PIK3CA (39%) and PTEN (20%) mutations were more common in cell lines than tumors, suggesting a selection for these but not AKT1 mutations during adaptation to culture. PIK3CA mutations did not have a significant impact on outcome in 166 hormone receptor-positive breast cancer patients after adjuvant tamoxifen. PIK3CA mutations, in comparison with PTEN loss and AKT1 mutations, were associated with significantly less and indeed inconsistent activation of AKT and of downstream PI3K/AKT signaling in tumors and cell lines, and PTEN loss and PIK3CA mutation were frequently concordant, suggesting different contributions to pathophysiology. PTEN loss but not PIK3CA mutations rendered cells sensitive to growth inhibition by the PI3K inhibitor LY294002. Thus, PI3K pathway aberrations likely play a distinct role in the pathogenesis of different breast cancer subtypes. The specific aberration may have implications for the selection of PI3K-targeted therapies in hormone receptor-positive breast cancer.

  20. Thermodynamic, electronic, and magnetic properties of intrinsic vacancy defects in antiperovskite Ca3SnO

    Science.gov (United States)

    Batool, Javaria; Alay-e-Abbas, Syed Muhammad; Amin, Nasir

    2018-04-01

    The density functional theory based total energy calculations are performed to examine the effect of charge neutral and fully charged intrinsic vacancy defects on the thermodynamic, electronic, and magnetic properties of Ca3SnO antiperovskite. The chemical stability of Ca3SnO is evaluated with respect to binary compounds CaO, CaSn, and Ca2Sn, and the limits of atomic chemical potentials of Ca, Sn, and O atoms for stable synthesis of Ca3SnO are determined within the generalized gradient approximation parametrization scheme. The electronic properties of the pristine and the non-stoichiometric forms of this compound have been explored and the influence of isolated intrinsic vacancy defects (Ca, Sn, and O) on the structural, bonding, and electronic properties of non-stoichiometric Ca3SnO are analyzed. We also predict the possibility of achieving stable ferromagnetism in non-stoichiometric Ca3SnO by means of charge neutral tin vacancies. From the calculated total energies and the valid ranges of atomic chemical potentials, the formation energetics of intrinsic vacancy defects in Ca3SnO are evaluated for various growth conditions. Our results indicate that the fully charged calcium vacancies are thermodynamically stable under the permissible Sn-rich condition of stable synthesis of Ca3SnO, while tin and oxygen vacancies are found to be stable under the extreme Ca-rich condition.

  1. Synthesis and characterization of nano-sized CaCO3 in purified diet

    Science.gov (United States)

    Mulyaningsih, N. N.; Tresnasari, D. R.; Ramahwati, M. R.; Juwono, A. L.; Soejoko, D. S.; Astuti, D. A.

    2017-07-01

    The growth and development of animals depend strongly on the balanced nutrition in the diet. This research aims is to characterize the weight variations of nano-sized calcium carbonate (CaCO3) in purified diet that to be fed to animal model of rat. The nano-sized CaCO3 was prepared by milling the calcium carbonate particles for 20 hours at a rotation speed of 1000 rpm and resulting particle size in a range of 2-50 nm. Nano-sized CaCO3 added to purified diet to the four formulas that were identified as normal diet (N), deficiency calcium (DC), rich in calcium (RC), and poor calcium (PC) with containing in nano-sized CaCO3 much as 0.50 %, 0.00 %, 0.75 % and 0.25 % respectively. The nutritional content of the purified diet was proximate analyzed, it resulted as followed moisture, ash, fat, protein, crude fiber. The quantities of chemical element were analyzed by atomic absorption spectrometry (AAS), it resulted iron, magnesium, potassium and calcium. The results showed that N diet (Ca: 16,914.29 ppm) were suggested for healthy rats and RC diet (Ca: 33,696.13 ppm) for conditioned osteoporosis rats. The crystalline phases of the samples that were examined by X-ray diffraction showed that crystalline phase increased with the increasing concentration of CaCO3.

  2. Spontaneous release from mossy fiber terminals inhibits Ni2+-sensitive T-type Ca2+ channels of CA3 pyramidal neurons in the rat organotypic hippocampal slice.

    Science.gov (United States)

    Reid, Christopher A; Xu, Shenghong; Williams, David A

    2008-01-01

    Mossy fibers (axons arising from dentate granule cells) form large synaptic contacts exclusively onto the proximal apical dendrites of CA3 pyramidal neurons. They can generate large synaptic currents that occur in close proximity to the soma. These properties mean that active conductance in the proximal apical dendrite could have a disproportionate influence on CA3 pyramidal neuron excitability. Ni(2+)-sensitive T-type Ca(2+) channels are important modulators of dendritic excitability. Here, we use an optical approach to determine the contribution of Ni(2+) (100 microM)-sensitive Ca(2+) channels to action potential (AP) elicited Ca(2+) flux in the soma, proximal apical and distal apical dendrites. At resting membrane potentials Ni(2+)-sensitive Ca(2+) channels do not contribute to the Ca(2+) signal in the proximal apical dendrite, but do contribute in the other cell regions. Spontaneous release from mossy fiber terminals acting on 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)-sensitive postsynaptic channels underlies a tonic inhibition of Ni(2+)-sensitive channels. Chelating Zn(2+) with CaEDTA blocks CNQX-sensitive changes in Ca(2+) flux implicating a mechanistic role of this ion in T-type Ca(2+) channel block. To test if this inhibition influenced excitability, progressively larger depolarizing pulses were delivered to CA3 pyramidal neurons. CNQX significantly reduced the size of the depolarizing step required to generate APs and increased the absolute number of APs per depolarizing step. This change in AP firing was completely reversed by the addition of Ni(2+). This mechanism may reduce the impact of T-type Ca(2+) channels in a region where large synaptic events are common.

  3. Capsicum annuum transcription factor WRKYa positively regulates defense response upon TMV infection and is a substrate of CaMK1 and CaMK2.

    Science.gov (United States)

    Huh, Sung Un; Lee, Gil-Je; Jung, Ji Hoon; Kim, Yunsik; Kim, Young Jin; Paek, Kyung-Hee

    2015-01-23

    Plants are constantly exposed to pathogens and environmental stresses. To minimize damage caused by these potentially harmful factors, plants respond by massive transcriptional reprogramming of various stress-related genes via major transcription factor families. One of the transcription factor families, WRKY, plays an important role in diverse stress response of plants and is often useful to generate genetically engineered crop plants. In this study, we carried out functional characterization of CaWRKYa encoding group I WRKY member, which is induced during hypersensitive response (HR) in hot pepper (Capsicum annuum) upon Tobacco mosaic virus (TMV) infection. CaWRKYa was involved in L-mediated resistance via transcriptional reprogramming of pathogenesis-related (PR) gene expression and affected HR upon TMV-P0 infection. CaWRKYa acts as a positive regulator of this defense system and could bind to the W-box of diverse PR genes promoters. Furthermore, we found Capsicum annuum mitogen-activated protein kinase 1 (CaMK1) and 2 (CaMK2) interacted with CaWRKYa and phosphorylated the SP clusters but not the MAPK docking (D)-domain of CaWRKYa. Thus, these results demonstrated that CaWRKYa was regulated by CaMK1 and CaMK2 at the posttranslational level in hot pepper.

  4. Effect of rabdosia rubescens combined with new assistant chemotherapy on serum CA199, CEA, CA15-3 and T lymphocyte subsets in patients with breast cancer

    Directory of Open Access Journals (Sweden)

    Lei Xi

    2018-07-01

    Full Text Available Objective: To study the effects of Rabdosia rubescens combined with neoadjuvant chemotherapy on serum CA199, CEA, CA15-3 levels and T lymphocyte subsets in patients with breast cancer. Methods: A total of 70 patients with breast cancer in our hospital were enrolled as the subjects of this study. The subjects were divided into control group (n=35 and treatment group (n=35 randomly. Patients in the control group were treated with new assistant chemotherapy, while those who were in the treatment group were treated with rabdosia rubescens combined with new assistant chemotherapy. The two groups of patients were treated for 3 periods. The serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before and after treatment were compared. Results: There were no significantly differences among the serum CA199, CEA, CA15-3 levels and peripheral blood CD4+, CD8+, CD4+/CD8+ cells of the two groups before treatment. The serum CA199, CEA and CA15-3 levels of the two groups after treatment were significantly lower than those before treatment, besides, the serum CA199, CEA and CA15-3 levels of the treatment group were significantly lower than those of the control group. The peripheral blood CD4+, CD4+/ CD8+ cells of the control group after treatment were significantly lower than before treatment, and the peripheral blood CD4+, CD4+/CD8+ cells of the treatment group after treatment were significantly higher than those of the control group. Conclusion: Rabdosia rubescens combined with new assistant chemotherapycan can significantly reduce the serum CA199, CEA and CA15-3 levels, and improve peripheral blood CD4+, CD8+, CD4+/CD8+ levels of patients with breast cancer. It is worthy of clinical application.

  5. DISC1 Modulates Neuronal Stress Responses by Gate-Keeping ER-Mitochondria Ca2+ Transfer through the MAM

    Directory of Open Access Journals (Sweden)

    Sung Jin Park

    2017-12-01

    Full Text Available Summary: A wide range of Ca2+-mediated functions are enabled by the dynamic properties of Ca2+, all of which are dependent on the endoplasmic reticulum (ER and mitochondria. Disrupted-in-schizophrenia 1 (DISC1 is a scaffold protein that is involved in the function of intracellular organelles and is linked to cognitive and emotional deficits. Here, we demonstrate that DISC1 localizes to the mitochondria-associated ER membrane (MAM. At the MAM, DISC1 interacts with IP3R1 and downregulates its ligand binding, modulating ER-mitochondria Ca2+ transfer through the MAM. The disrupted regulation of Ca2+ transfer caused by DISC1 dysfunction leads to abnormal Ca2+ accumulation in mitochondria following oxidative stress, which impairs mitochondrial functions. DISC1 dysfunction alters corticosterone-induced mitochondrial Ca2+ accumulation in an oxidative stress-dependent manner. Together, these findings link stress-associated neural stimuli with intracellular ER-mitochondria Ca2+ crosstalk via DISC1, providing mechanistic insight into how environmental risk factors can be interpreted by intracellular pathways under the control of genetic components in neurons. : Park et al. show that DISC1 regulates ER-mitochondria Ca2+ transfer through mitochondria-associated ER membrane (MAM. DISC1 dysfunction at MAM increases ER-mitochondria Ca2+ transfer during oxidative stress and excessive amounts of corticosterone, which impairs mitochondrial function. Keywords: DISC1, MAM, mitochondria, Ca2+, IP3R1, oxidative stress

  6. Place cell rate remapping by CA3 recurrent collaterals.

    Directory of Open Access Journals (Sweden)

    Trygve Solstad

    2014-06-01

    Full Text Available Episodic-like memory is thought to be supported by attractor dynamics in the hippocampus. A possible neural substrate for this memory mechanism is rate remapping, in which the spatial map of place cells encodes contextual information through firing rate variability. To test whether memories are stored as multimodal attractors in populations of place cells, recent experiments morphed one familiar context into another while observing the responses of CA3 cell ensembles. Average population activity in CA3 was reported to transition gradually rather than abruptly from one familiar context to the next, suggesting a lack of attractive forces associated with the two stored representations. On the other hand, individual CA3 cells showed a mix of gradual and abrupt transitions at different points along the morph sequence, and some displayed hysteresis which is a signature of attractor dynamics. To understand whether these seemingly conflicting results are commensurate with attractor network theory, we developed a neural network model of the CA3 with attractors for both position and discrete contexts. We found that for memories stored in overlapping neural ensembles within a single spatial map, position-dependent context attractors made transitions at different points along the morph sequence. Smooth transition curves arose from averaging across the population, while a heterogeneous set of responses was observed on the single unit level. In contrast, orthogonal memories led to abrupt and coherent transitions on both population and single unit levels as experimentally observed when remapping between two independent spatial maps. Strong recurrent feedback entailed a hysteretic effect on the network which diminished with the amount of overlap in the stored memories. These results suggest that context-dependent memory can be supported by overlapping local attractors within a spatial map of CA3 place cells. Similar mechanisms for context-dependent memory may

  7. Pengaruh Kombinasi Senyawa Humik dan CaCO3 terhadap Alumunium dan Fosfat Typic Paleudult Kentrong Banten

    Directory of Open Access Journals (Sweden)

    Sugeng Winarso

    2009-05-01

    Full Text Available Decomposition of organic matter releases humic compounds, that can chelate metals include Al in acidic soils. This chelation of Al is important for decreasing of Al activity and P fixation in acidic soils. This study was aimed to test the effect of humic compounds extracted from rice-straw compost and CaCO3 combination on aluminium activity and phosphate (available P on an Ultisol (Typic Paleudult collected from Kentrong Banten. A laboratory study was conducted by series consentration of CaCO3 (0, 500, 1.000, 2.000, dan 3.000 ppm in 8 grams of acidic soil. The acidic soil had previously been subjected to continuously addition of humic compounds and none. Then, these mix of soil and CaCO3 were added 40 ml contained 5.000 ppm humic compounds to obtain 1:5 soil:suspension ratio and control was made by using aquadest. They were shaked for 2 hours every day and pH was measured. At 11st days incubation Alexch (N KCl and soluble of P (PB and PC were measured. The results showed that liming or addition of CaCO3 to the acidic soils decreased Alexch (precipitated to be Al(OH3 linearly with formula y = -0.778x + 6.108; y = Alexch (Cmol kg-1, x = CaCO3 (M; R² = 0,916. Combination addition of humic compounds and CaCO3 was able to increase pH and Alexch up to not detected. The increased of P-soluble or desorption P untill 384% took place at addition of 0.0016 M CaCO3 and 5000 ppm humic compounds. More desorption of P was observed if the acidic soils has previously been subjected to continuously addition of humic compounds, such us the increased of soluble P up to 739% at addition of CaCO3 0.0008 M.

  8. A molecular dynamics study of the atomic structure of (CaO)x(SiO2)1-x glasses.

    Science.gov (United States)

    Mead, Robert N; Mountjoy, Gavin

    2006-07-27

    The local atomic environment of Ca in (CaO)x(SiO2)1-x glasses is of interest because of the role of Ca in soda-lime glass, the application of calcium silicate glasses as biomaterials, and the previous experimental measurement of the Ca-Ca correlation in CaSiO(3) glass. Molecular dynamics has been used to obtain models of (CaO)x(SiO2)1-x glasses with x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5, and with approximately 1000 atoms and size approximately 25 A. As expected, the models contain a tetrahedral silica network, the connectivity of which decreases as x increases. In the glass-forming region, i.e., x = 0.4 and 0.5, Ca has a mixture of 6- and 7-fold coordination. Bridging oxygen makes an important contribution to the coordination of Ca, with most bridging oxygens coordinated to 2 Si plus 1 Ca. The x = 0.5 model is in reasonable agreement with previous experimental studies, and does not substantiate the previous theory of cation ordering, which predicted Ca arranged in sheets. In the phase-separated region, i.e., x = 0.1 and 0.2, there is marked clustering of Ca.

  9. Phase diagram study for the PbO-ZnO-CaO-SiO{sub 2} -“Fe{sub 2}O{sub 3} ” system in air with CaO/SiO{sub 2} in 1.1 and PbO/(CaO+SiO{sub 2}) in 2.4 weight ratios

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodriguez, Josue; Romero-Serrano, Antonio; Hernandez-Ramirez, Aurelio; Cruz-Ramirez, Alejandro, E-mail: romeroipn@hotmail.com [Instituto Politecnico Nacional-ESIQIE, Zacatenco, Mexico City (Mexico); Almaguer-Guzman, Isaias; Benavides-Perez, Ricardo; Flores-Favela, Manuel [Servicios Administrativos Penoles S.A de C.V., Torreon, Coahuila (Mexico)

    2017-07-15

    An experimental study on the phase equilibrium and the liquidus isotherms for the PbO-ZnO-CaO-SiO{sub 2} -“Fe{sub 2}O{sub 3} ” system with CaO/SiO{sub 2} in 1.1 and PbO/(CaO+SiO{sub 2}) in 2.4 weight ratios, respectively, was carried out in the temperature range 1100-1300 deg C (1373-1573 K). High temperature phases were determined by the equilibrium-quenching method. Results are presented in the form of pseudo-ternary sections “Fe{sub 2}O{sub 3} ”-ZnO-(PbO+CaO+SiO{sub 2}). X-Ray diffraction (XRD) and SEM-EDS results showed that the phase equilibria in this system are dominated by the high melting temperature spinel and zincite phases. It was observed that if the system is at a temperature below 1300 deg C and the total (Fe{sub 2}O{sub 3} + ZnO) is greater than 20 wt%, spinel and/or zincite will be present in the slag system. As an application of the phase diagram, the liquid phase compositions below the liquidus surface were estimated, then their viscosities were calculated using FACTSage software. (author)

  10. Monte Carlo simulation of roughness effect on magnetic and magnetotransport behavior of La{sub 2/3}Ca{sub 1/3}MnO{sub 3}/La{sub 1/3}Ca{sub 2/3}MnO{sub 3} bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Agudelo-Giraldo, J.D. [PCM Computational Applications, Universidad Nacional de Colombia-Sede Manizales, Km. 9 vía al aeropuerto, Manizales (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [PCM Computational Applications, Universidad Nacional de Colombia-Sede Manizales, Km. 9 vía al aeropuerto, Manizales (Colombia); Restrepo, J. [Grupo de Magnetismo y Simulación, Instituto de Física, Universidad de Antioquia, A.A., 1226 Medellín (Colombia)

    2014-02-01

    In this work we address the study of the magnetic and magnetotransport properties of ferromagnetic (FM)/antiferromagnetic (AFM) La{sub 2/3}Ca{sub 1/3}MnO{sub 3}/La{sub 1/3}Ca{sub 2/3}MnO{sub 3} manganites bilayers by means of the standard Monte Carlo method. Simulations, implemented with a single spin flip Metropolis dynamics, were performed in the framework of a three-dimensional classical Heisenberg model. Four different superexchange interactions, with the two different types of ions Mn{sup 3+} and Mn{sup 4+} involved and the orbital differences accounting for the Mn{sup 3+} ions, were considered in the Hamiltonian. Likewise, terms dealing with magnetocrystalline anisotropy and the influence of an external applied magnetic field were also included. Samples were simulated having dimensions L×L×(d{sub FM}+d{sub AFM}) where L, measured in lattice parameter units, stands for the linear and lateral dimension along which periodic boundary conditions were implemented, whereas d{sub FM} and d{sub AFM} stand for the thicknesses of FM and AFM layers respectively with free boundary conditions. Different degrees of roughness at the interface were also simulated in order to analyze its influence on the magnetic and magnetotransport properties of the system. In particular, low-temperature results reveal a trend of the coercive field to increase with roughness contrary to the exchange bias field behavior, which tends to decrease. Both quantities are modulated by oscillations ascribed to the atomic disorder at the interface. Finally, the roughness effect upon the bilayer resistivity and on the metal–insulator temperature is also presented and discussed.

  11. Luminescence properties of undoped CsCaCl3 and CsSrCl3 crystalline scintillators

    International Nuclear Information System (INIS)

    Fujimoto, Yutaka; Saeki, Keiichiro; Koshimizu, Masanori; Asai, Keisuke; Yanagida, Takayuki

    2015-01-01

    Intrinsic luminescence properties of undoped CsCaCl 3 and CsSrCl 3 crystalline scintillators were studied. The crystal samples were grown by a vertical Bridgman method. Photoluminescence spectra of the crystals showed Auger-free luminescence (AFL) at 310 nm and self-trapped emission (STE) at 400 nm for CsCaCl 3 and 465 nm for CsSrCl 3 , when vacuum ultraviolet (VUV) light at 84 nm and 160 nm excited the crystals. X-ray excited radioluminescence spectra of the crystals showed some emission bands in the 280-600 nm wavelength range, which are owing to AFL, STE, and other origins such as lattice defects and impurities. Scintillation light yield was 400-300 ph/MeV, and the principal scintillation decay time about 2.5 ns and 12 ns for CsCaCl 3 and 1.8 ns and 13 ns for CsSrCl 3 . (author)

  12. Study of heat conductivity, electric conductivity and thermo-emf of BiSrCaCu2Ox and Bi1.82Sr1.73Ca1.73Ca1.25Cu2.2Ox systems

    International Nuclear Information System (INIS)

    Zhukova, T.B.; Parfen'eva, L.S.; Popov, V.V.; Melekh, B.T.; Smirnov, I.A.; Khalmedov, Kh.M.

    1991-01-01

    Phase compositions are determined and temperature dependences are measured of x-heat conductivity, ρ-electric resistance and α-thermo-emf of polycrystal, monophase, highly textured HTSC samples of BiSrCaCu 2 O x and Bi 1.82 Sr 1.73 Ca 1.25 Cu 2.2 O x produced through method of direct induction melting in the air in a cold container. Sample 'aging' after storage in the air and vacuum, leading to decrease in the number of foring phases and increase in the basic phase content as well as to change of x, ρ and α coefficients is identified

  13. PDGF-induced migration of synthetic vascular smooth muscle cells through c-Src-activated L-type Ca2+ channels with full-length CaV1.2 C-terminus.

    Science.gov (United States)

    Guo, Xiaoguang; Kashihara, Toshihide; Nakada, Tsutomu; Aoyama, Toshifumi; Yamada, Mitsuhiko

    2018-06-01

    In atherosclerosis, vascular smooth muscle cells (VSMC) migrate from the media toward the intima of the arteries in response to cytokines, such as platelet-derived growth factor (PDGF). However, molecular mechanism underlying the PDGF-induced migration of VSMCs remains unclear. The migration of rat aorta-derived synthetic VSMCs, A7r5, in response to PDGF was potently inhibited by a Ca V 1.2 channel inhibitor, nifedipine, and a Src family tyrosine kinase (SFK)/Abl inhibitor, bosutinib, in a less-than-additive manner. PDGF significantly increased Ca V 1.2 channel currents without altering Ca V 1.2 protein expression levels in A7r5 cells. This reaction was inhibited by C-terminal Src kinase, a selective inhibitor of SFKs. In contractile VSMCs, the C-terminus of Ca V 1.2 is proteolytically cleaved into proximal and distal C-termini (PCT and DCT, respectively). Clipped DCT is noncovalently reassociated with PCT to autoinhibit the channel activity. Conversely, in synthetic A7r5 cells, full-length Ca V 1.2 (Ca V 1.2FL) is expressed much more abundantly than truncated Ca V 1.2. In a heterologous expression system, c-Src activated Ca V 1.2 channels composed of Ca V 1.2FL but not truncated Ca V 1.2 (Ca V 1.2Δ1763) or Ca V 1.2Δ1763 plus clipped DCT. Further, c-Src enhanced the coupling efficiency between the voltage-sensing domain and activation gate of Ca V 1.2FL channels by phosphorylating Tyr1709 and Tyr1758 in PCT. Compared with Ca V 1.2Δ1763, c-Src could more efficiently bind to and phosphorylate Ca V 1.2FL irrespective of the presence or absence of clipped DCT. Therefore, in atherosclerotic lesions, phenotypic switching of VSMCs may facilitate pro-migratory effects of PDGF on VSMCs by suppressing posttranslational Ca V 1.2 modifications.

  14. Usefulness of CA 130 kit based on IRMA

    International Nuclear Information System (INIS)

    Fujii, Takashi; Kimura, Yoshiko; Ata, Mariko; Miyagawa, Naoko; Iio, Atsushi; Hamamoto, Ken

    1988-01-01

    Immunoradiometric assay for CA 130 was fundamentally and clinically evaluated using a commercially available D-7111 kit. Incubation time was 4 hr with the present CA 133 kit as compared with 16 - 24 hr with conventional CA 125 kit. Laboratory performance of CA 130 kit was satisfactory for standard curve, reproducibility, and recovery test. There was well correlation between the present CA 130 kit and CA 125 kit (r = 0.931). The concentration of CA 130 in the serum was significantly higher in healthy women than men (17.3 +- 10.5 U/ml vs 9.6 +- 5.1 U/ml). Serum CA 130 levels tended to decrease with aging, regardless of sex. These levels were changeable with menstrual cycle ; i.e., these were significantly higher during menstrual phase (24.2 +- 9.0 U/ml) and significantly lower during ovulatory phase (10.9 +- 2.4 U/ml) and during menopause (12.1 +- 3.4 U/ml). Cut off serum CA 130 levels were defined as 20 U/ml for men and 38 U/ml for women. Positive rate for CA 130 was the highest in cases of ovarian cancer (80 %), followed by endometrial cancer (50 %), pancreatic cancer (47 %), benign ovarian tumor (44 %), and lung cancer (39 %). (Namekawa, K.)

  15. Long-term sustainability of microbial-induced CaCO3 precipitation in aqueous media.

    Science.gov (United States)

    Gat, Daniella; Ronen, Zeev; Tsesarsky, Michael

    2017-10-01

    Microbially induced CaCO 3 precipitation (MICP) via urea hydrolysis is an emerging technique for soil amelioration, building materials rehabilitation and pollutants sequestration amongst other various environmental applications. The successful application of MICP requires the sustainability of the precipitated CaCO 3 ; to which the fate of ammonia, the main by-product of ureolysis, is potentially significante. Ammonia volatilization and biological ammonia oxidation both induce a pH decrease, which, in turn, might cause CaCO 3 dissolution. To examine the potential effect of accumulated ammonia on precipitated CaCO 3 , we conducted a long-term MICP batch experiment, using environmental enrichment cultures of ureolytic bacteria. Here we show that CaCO 3 precipitation was completed within 15-27 days, along with a rise in ammonium concentration. Following completion of ureolysis and precipitation, ammonium concentrations decreased, leading to a pH decrease. About 30 days after precipitation was completed, as much as 30% CaCO 3 dissolution, was observed. A two-step model, describing urea hydrolysis followed by the removal of ammonia from the precipitation solution, predicted CaCO 3 dissolution due to ammonia volatilization. We suggest that ureolytic MICP might result in ammonia volatilization, leading to significant CaCO 3 dissolution. These results provide basic insights into the sustainability of ureolytic MICP and should further encourage removal of the accumulated ammonia from the treated site. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Influence of the particle size reduction on magnetic properties of electron-doped Ca1-xYxMnO3

    OpenAIRE

    Alqat Aboalqasim; Gebrel Zohra; Spasojević Vojislav; Kusigerski Vladan; Bošković Snežana; Blanuša Jovan

    2012-01-01

    The electron-doped magnetic nanoparticles of Ca1-xYxMnO3 (x = 0, 0.05, 0.10, 0.15, 0.20, and 0.30) manganite with an average particle size of 50 nm are analyzed and discussed in relation to their bulk counterparts. Nanoparticle samples show dominant anti-ferromagnetic ordering with a significant increase of coercivity, with the maximum value of 0.9 T for x = 0. Particle size reduction in Ca1-xYxMnO3 retains the bulk-like magnetic behavior of samples having up to 15% of Y3+, with the sma...

  17. The sequence of the CA-SP1 junction accounts for the differential sensitivity of HIV-1 and SIV to the small molecule maturation inhibitor 3-O-{3',3'-dimethylsuccinyl}-betulinic acid

    Directory of Open Access Journals (Sweden)

    Aiken Christopher

    2004-06-01

    Full Text Available Abstract Background Despite the effectiveness of currently available antiretroviral therapies in the treatment of HIV-1 infection, a continuing need exists for novel compounds that can be used in combination with existing drugs to slow the emergence of drug-resistant viruses. We previously reported that the small molecule 3-O-{3',3'-dimethylsuccinyl}-betulinic acid (DSB specifically inhibits HIV-1 replication by delaying the processing of the CA-SP1 junction in Pr55Gag. By contrast, SIVmac239 replicates efficiently in the presence of high concentrations of DSB. To determine whether sequence differences in the CA-SP1 junction can fully account for the differential sensitivity of HIV-1 and SIV to DSB, we engineered mutations in this region of two viruses and tested their sensitivity to DSB in replication assays using activated human primary CD4+ T cells. Results Substitution of the P2 and P1 residues of HIV-1 by the corresponding amino acids of SIV resulted in strong resistance to DSB, but the mutant virus replicated with reduced efficiency. Conversely, replication of an SIV mutant containing three amino acid substitutions in the CA-SP1 cleavage site was highly sensitive to DSB, and the mutations resulted in delayed cleavage of the CA-SP1 junction in the presence of the drug. Conclusions These results demonstrate that the CA-SP1 junction in Pr55Gag represents the primary viral target of DSB. They further suggest that the therapeutic application of DSB will be accompanied by emergence of mutant viruses that are highly resistant to the drug but which exhibit reduced fitness relative to wild type HIV-1.

  18. Control of ciliary motility by Ca2+: Integration of Ca2+-dependent functions and targets for Ca2+ action

    International Nuclear Information System (INIS)

    Evans, T.C.

    1988-01-01

    To identify functions that regulate Ca 2+ -induced ciliary reversal in Paramecium, mutants defective in terminating depolarization-induced backward swimming were selected. Six independent recessive mutations (k-shy) comprising two complementation groups, k-shyA and k-shyB, were identified. All mutants exhibited prolonged backward swimming in depolarizing solutions. Voltage clamp studies revealed that mutant Ca 2+ current amplitudes were reduced, but could be restored to wild type levels by EGTA injection. The recovery of the mutant Ca 2+ current from Ca 2+ -dependent inactivation, and the decay of the Ca 2+ -dependent K + and Ca 2+ -dependent Na + currents after depolarization were slow in k-shy compared to wild type. To identify protein targets of Ca 2+ action, ciliary proteins that interact with calmodulin (CaM) were characterized. With a 125 I-CaM blot assay, several CaM-binding proteins were identified including axonemal, soluble, and membrane-bound polypeptides. Competitive displacement studies with unlabeled Paramecium CaM, bovine CaM, and troponinC suggested that both protein types bind CaM with high affinity and specificity. To examine the presence of CaM-binding sites in intact axonemes, a filtration binding assay was developed

  19. Sigma-1 receptor chaperones at the ER-mitochondrion interface regulate Ca(2+) signaling and cell survival.

    Science.gov (United States)

    Hayashi, Teruo; Su, Tsung-Ping

    2007-11-02

    Communication between the endoplasmic reticulum (ER) and mitochondrion is important for bioenergetics and cellular survival. The ER supplies Ca(2+) directly to mitochondria via inositol 1,4,5-trisphosphate receptors (IP3Rs) at close contacts between the two organelles referred to as mitochondrion-associated ER membrane (MAM). We found here that the ER protein sigma-1 receptor (Sig-1R), which is implicated in neuroprotection, carcinogenesis, and neuroplasticity, is a Ca(2+)-sensitive and ligand-operated receptor chaperone at MAM. Normally, Sig-1Rs form a complex at MAM with another chaperone, BiP. Upon ER Ca(2+) depletion or via ligand stimulation, Sig-1Rs dissociate from BiP, leading to a prolonged Ca(2+) signaling into mitochondria via IP3Rs. Sig-1Rs can translocate under chronic ER stress. Increasing Sig-1Rs in cells counteracts ER stress response, whereas decreasing them enhances apoptosis. These results reveal that the orchestrated ER chaperone machinery at MAM, by sensing ER Ca(2+) concentrations, regulates ER-mitochondrial interorganellar Ca(2+) signaling and cell survival.

  20. Effect of Eu{sup 3+} doping on the structural and photoluminescence properties of cubic CaCO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Yan; Sun, Yidi; Zou, Haifeng; Sheng, Ye; Zhou, Xiuqing; Zhang, Bowen; Zhou, Bing, E-mail: zhoubing@jlu.edu.cn

    2016-01-15

    Graphical abstract: - Highlights: • The doping of Eu{sup 3+} ions decreased the size of CaCO{sub 3} nanoparticles. • The doping of Eu{sup 3+} ions brought about the change of CaCO{sub 3}'s optical bandgap. • Multiple sites of Eu{sup 3+} in CaCO{sub 3} nanocrystals have been identified. - Abstract: CaCO{sub 3}:xEu{sup 3+} (x = 0, 0.010, 0.015, 0.020, and 0.025) cubic nanoparticles were synthesized by carbonation method. The powder XRD patterns and SEM images of the CaCO{sub 3}:xEu{sup 3+} nanoparticles demonstrate that both the crystalline sizes and average particle sizes of synthesized samples decreased with the increase of Eu{sup 3+} content until x = 0.020. Kubelka–Munk plots and bandgap energy estimation indicate that the doping of Eu{sup 3+} ions changed optical bandgap of CaCO{sub 3}. Photoluminescence (PL) spectra show that the PL intensity of the CaCO{sub 3}:xEu{sup 3+} nanoparticles was enhanced with the increase of Eu{sup 3+} content in cubic CaCO{sub 3}:xEu{sup 3+}, and concentration quenching occurred when Eu{sup 3+} concentration exceeded 2.0 mol%. In addition, the doped sites of Eu{sup 3+} in CaCO{sub 3} crystalline were identified by the site-selective spectroscopy and decay curves.

  1. Why Do Organisms in the Atlantic Ocean Produce So Much CaCO3?

    Science.gov (United States)

    Toggweiler, J. R.

    2010-12-01

    Sediments in the Atlantic are richer in CaCO3 than sediments in the other oceans. Sediment trap observations show that sinking particles in the Atlantic also tend to have more CaCO3 in relation to organic carbon than sinking particles elsewhere. The reason for the extra production of CaCO3 has never been very clear. The Atlantic is unusual because it receives much more than its share of the global input of river water. River water adds alkalinity to the surface ocean while the production of CaCO3 takes it away. In this presentation a new tracer, called Alk*, is derived from the surface alkalinity distribution to highlight the impact of river inputs and the production of CaCO3. If the production of CaCO3 were evenly distributed across the ocean one would expect the Atlantic to have a higher level of Alk* becaused of its river inputs. We find instead that Alk* is lower in the middle of the Atlantic than almost any place else. This, of course, is consistent with the fact that organisms in the Atlantic produce a lot of CaCO3. Comparison with other areas with especially low values of Alk* (Red Sea and northern Arabian Sea) shows that the production of CaCO3 is highly correlated across the ocean with the surface salinity. Hence, we argue that organisms in the Atlantic produce a lot of CaCO3 simply because the Atlantic is so salty. Salty waters, by definition, have more CO3= ions, which increase the supersaturation with respect to calcite and aragonite. This finding, while extremely simple, has major implifications for the impact of ocean acidification on calcifying organisms.

  2. Specificity of drug transport mediated by CaMDR1: a major facilitator ...

    Indian Academy of Sciences (India)

    Unknown

    CaMDR1 encodes a major facilitator superfamily (MFS) protein in Candida albicans whose expression has been linked to .... by plaque assay and the integration of CaMDR1 at the ... with recombinant virus, vAcCaMDR1 and cells infected.

  3. Tumor markers in the early detection of tumor recurrence in breast cancer patients: CA 125, CYFRA 21-1, HER2 shed antigen, LDH and CRP in combination with CEA and CA 15-3.

    Science.gov (United States)

    Di Gioia, Dorit; Blankenburg, Irene; Nagel, Dorothea; Heinemann, Volker; Stieber, Petra

    2016-10-01

    Kinetics of CA 15-3 and CEA have a high specificity in the early detection of metastatic breast cancer (MBC). However, this high specificity is associated with a lack of sensitivity. To decrease the number of false negative patients, the additional diagnostic potential of an extended panel of biomarkers was evaluated. This analysis was performed as part of a large follow-up study (1998-2010) evaluating 813 patients with a median follow-up of 63months. After primary therapy, all patients underwent tumor marker monitoring for CEA and CA 15-3 at 6-week intervals. A reproducible previously defined increase (≥100%) based on the individual baseline value of each patient was considered as a strong indicator of MBC. For the present analysis, we retrospectively evaluated 1011 blood samples from 95 patients. Forty-seven of these had metastatic disease for the first time at the time of this evaluation, while the remaining 48 patients showed no evidence of disease. The sera of these patients were additionally assessed for the following parameters: cancer antigen (CA) 125, cytokeratin-19 soluble fragment (CYFRA 21-1), HER2 shed antigen, lactate-dehydrogenase (LDH) and C-reactive protein (CRP). 26 of 47 patients with MBC showed a reproducible tumor marker increase of at least CEA and/or CA 15-3 (55.3%, true-positive). The remaining 21 patients with MBC showed no increase in CEA or CA 15-3 (44.7%, false negative, FN). By combining all markers mentioned above, 41 of 47 patients with MBC showed a reproducible marker increase with a sensitivity of 87.2% and specificity of 100%. This retrospective analysis indicates that a panel of biomarkers can increase the sensitivity of the CA 15-3/CEA combination without loss of specificity. The combined use is therefore helpful for early detection of MBC. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. How informative are spatial CA3 representations established by the dentate gyrus?

    Directory of Open Access Journals (Sweden)

    Erika Cerasti

    2010-04-01

    Full Text Available In the mammalian hippocampus, the dentate gyrus (DG is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhinal cortex layer II cells, which project both to the dentate gyrus and to CA3. Computational models of episodic memory have hypothesized that the function of the mossy fibers is to enforce a new, well-separated pattern of activity onto CA3 cells, to represent a new memory, prevailing over the interference produced by the traces of older memories already stored on CA3 recurrent collateral connections. Can this hypothesis apply also to spatial representations, as described by recent neurophysiological recordings in rats? To address this issue quantitatively, we estimate the amount of information DG can impart on a new CA3 pattern of spatial activity, using both mathematical analysis and computer simulations of a simplified model. We confirm that, also in the spatial case, the observed sparse connectivity and level of activity are most appropriate for driving memory storage-and not to initiate retrieval. Surprisingly, the model also indicates that even when DG codes just for space, much of the information it passes on to CA3 acquires a non-spatial and episodic character, akin to that of a random number generator. It is suggested that further hippocampal processing is required to make full spatial use of DG inputs.

  5. The value of clinical expression of CA series in malignancy diagnosis

    International Nuclear Information System (INIS)

    Wei Zhenyuan; Wang Jie

    2002-01-01

    Objective: To study the diagnosis of liver cancer, coloprocto-carcinoma, ovary cancer, pancreatic carcinoma, breast cancer, lung cancer and stomach cancer by labelling immunoassay of CA50, CA125, CA199 and CA153. Methods: The authors had measured the serum content of these tumor markers in 67 liver cancer, 88 coloprocto-carcinoma, 48 ovary cancer, 36 pancreatic carcinoma, 34 breast cancer, 128 lung cancer, 271 stomach cancer and 68 normal controls with labelling immunoassay (LIA). The mean coefficient of variation for intra and inter batch-assay of CA50, CA125, CA199 and CA153 were 3.7% and 8.1%, 4.8% and 10.1%, 7.6% and 12.3%, 8.1% and 10.4% respectively. The average recovery ratio was between 95% and 107%. Results: The levels of CA50 in stomach cancer and coloprocto-carcinoma were significantly higher than those in normal controls (p < 0.001). The levels of CA125 in ovary cancer and lung cancer were significantly higher than in normal controls (p < 0.001). The levels of CA199 in pancreatic carcinoma cancer was significantly higher than those in normal controls (p < 0.001). The levels of CA153 in breast cancer was significantly higher than those in normal controls (p < 0.001). The mean levels of CA50, CA125, CA199 and CA153 in 68 normal controls were 12.4 +- 3.9 U/ml, 14.3 +- 3.9 U/ml, 14.3 +- 10.5 U/ml, 10.0 +- 8.4 U/ml and 15.2 +- 7.5 U/ml respectively. Conclusion: In present study of 672 cases, CA50 measurement seems to be most useful for diagnosis of gastric and coloprocto-carcinoma, CA125 for ovarian cancer, CA199 for pancreatic cancer and CA153 for breast cancer (p < 0.001)

  6. Photoluminescence properties of Eu(3+)/ Sm(3+) activated CaZr4(PO4)6 phosphors.

    Science.gov (United States)

    Nair, Govind B; Dhoble, S J

    2016-09-01

    Solid state reaction method was employed for the synthesis of a series of CaZr4(PO4)6: Eu(3+)/Sm(3+) phosphors. The red-emitting CaZr4(PO4)6:Eu(3+) phosphors can be efficiently excited at 396 nm and thereby, exhibit a strong red luminescence predominantly corresponding to the electric dipole transition at 615 nm. Under 405 nm excitation, CaZr4(PO4)6:Sm(3+) phosphors display orange emission with color temperatures approximately around 2200 K. The acquired results reveal that CaZr4(PO4)6: RE(3+) (RE = Eu, Sm) phosphors could be potential candidates for red and orange emitting phosphor, respectively, for UV/blue-pump LEDs.

  7. Cardiac microvascular endothelial cells express a functional Ca+ -sensing receptor.

    Science.gov (United States)

    Berra Romani, Roberto; Raqeeb, Abdul; Laforenza, Umberto; Scaffino, Manuela Federica; Moccia, Francesco; Avelino-Cruz, Josè Everardo; Oldani, Amanda; Coltrini, Daniela; Milesi, Veronica; Taglietti, Vanni; Tanzi, Franco

    2009-01-01

    The mechanism whereby extracellular Ca(2+) exerts the endothelium-dependent control of vascular tone is still unclear. In this study, we assessed whether cardiac microvascular endothelial cells (CMEC) express a functional extracellular Ca(2+)-sensing receptor (CaSR) using a variety of techniques. CaSR mRNA was detected using RT-PCR, and CaSR protein was identified by immunocytochemical analysis. In order to assess the functionality of the receptor, CMEC were loaded with the Ca(2+)-sensitive fluorochrome, Fura-2/AM. A number of CaSR agonists, such as spermine, Gd(3+), La(3+) and neomycin, elicited a heterogeneous intracellular Ca(2+) signal, which was abolished by disruption of inositol 1,4,5-trisphosphate (InsP(3)) signaling and by depletion of intracellular stores with cyclopiazonic acid. The inhibition of the Na(+)/Ca(2+) exchanger upon substitution of extracellular Na(+) unmasked the Ca(2+) signal triggered by an increase in extracellular Ca(2+) levels. Finally, aromatic amino acids, which function as allosteric activators of CaSR, potentiated the Ca(2+) response to the CaSR agonist La(3+). These data provide evidence that CMEC express CaSR, which is able to respond to physiological agonists by mobilizing Ca(2+) from intracellular InsP(3)-sensitive stores. Copyright 2008 S. Karger AG, Basel.

  8. Long-term effects of intravenous 1 alpha (OH)D3 combined with CaCO3 and low-calcium dialysis on secondary hyperparathyroidism and biochemical bone markers in patients on chronic hemodialysis

    DEFF Research Database (Denmark)

    Brandi, L; Daugaard, H; Nielsen, P K

    1996-01-01

    doses of CaCO3 and to reduce the doses of an aluminium-containing oral phosphate binder. A decrease in p-Ca2+ during dialysis was induced, and special care had to focus on the compliance to CaCO3, in order not to aggravate the secondary hyperparathyroidism. (2) The combination of 'low......The effects of intravenous administration of 1 alpha-hydroxycholecalciferol [1 alpha (OH)D3] in combination with CaCO3 and 'low-calcium dialysis' (1.25 mmol/l) on plasma (p) parathyroid hormone (PTH) and biochemical bone markers (osteocalcin, alkaline phosphatase, procollagen type 1 c......-terminal extension peptide) were examined in 54 patients on chronic hemodialysis with either normal or elevated PTH. Increasing doses of 1 alpha (OH)D3 were administered intravenously under careful control of p-Ca2+ and inorganic phosphate. Blood samples were obtained 1 week before the start of treatment...

  9. Performance Characteristics of CA 19-9 Radioimmunoassay and Clinical Significance of Serum CA 19-9 Assay in Patients with Malignancy

    International Nuclear Information System (INIS)

    Kim, Sang Eun; Shong, Young Kee; Cho, Bo Youn; Kim, Noe Kyeong; Koh, Chang Soon; Lee, Mun Ho; Hong, Seong Woon; Hong, Kee Suk

    1985-01-01

    To evaluate the performance characteristics of CA 19-9 radioimmunoassay and the clinical significance of serum CA 19-9 assay in patients with malignancy, serum. CA 19-9 levels were measured by radioimmunoassay using monoclonal antibody in 135 normal controls, 81 patients with various untreated malignancy, 9 patients of postoperative colon cancer without recurrence and 20 patients with benign gastrointestinal diseases, who visited Seoul National University Hospital from June, 1984 to March, 1985. The results were as follows; 1) The CA 19-9 radioimmunoassay was simple to perform and can be completed in one work day. And the between-assay reproducibility and the assay recovery were both excellent. 2) The mean serum CA 19-9 level in 135 normal controls was 8.4±4.2 U/mL. Normal upper limit of serum CA 19-9 was defined as 21.0 U/mL. 4 out of 135 (3.0%) normal controls showed elevated CA 19-9 levels above the normal upper limit. 3) One out of 20 (5.0%) patients with benign gastrointestinal diseases showed elevated serum CA 19-9 level above the normal upper limit. 4) In 81 patients with various untreated malignancy, 41 patients (50.6%) showed elevated serum CA 19-9 levels. 66.7% of 18 patients with colorectal cancer, 100% of 2 patients with pancreatic cancer, 100% of 3 patients with common bile duct cancer, 47.1% of 17 patients with stomach cancer, 28.6% of 28 patients with hepatoma and 60.0% of 5 gastrointestinal tract cancers showed elevated serum CA 19-9 levels. 5) The sensitivities of serum CA 19-9 related to respectability in colorectal and stomach cancer were 33.3% in resectable colorectal cancer, 83.3% in unresectable colorectal cancer, 41.7% in resectable stomach cancer, 60.0% in unresectable stomach cancer respectively. 6) The sensitivity of serum CA 19-9 in 9 patients of postoperative colorectal cancer without recurrence were 33.3% and significantly decreased compared with that of untreated colorectal cancer, 66.7% (p<0.05). 7) In Patients with colorectal cancer

  10. Synthesis and luminescent properties of CaCO3:Eu3+@SiO2 phosphors with core-shell structure

    Science.gov (United States)

    Liu, Min; Kang, Ming; Chen, Kexu; Mou, Yongren; Sun, Rong

    2018-03-01

    Integrating the processes of preparation of CaCO3:Eu3+ and its surface-coating, core-shell structured CaCO3:Eu3+@SiO2 phosphors with red emission were synthesized by the carbonation method and surface precipitation procedure using sodium silicate as silica source. The phase structure, thermal stability, morphology and luminescent property of the as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectrum, thermal analysis, field-emission scanning electron microscopy, transmission electron microscope and photoluminescence spectra. The experimental results show that Eu3+ ions as the luminescence center are divided into two types: one is at the surface of the CaCO3 and the other inhabits the site of Ca2+. For CaCO3:Eu3+@SiO2 phosphors, the SiO2 layers are continuously coated on the surface of CaCO3:Eu3+ and show a typical core-shell structure. After coated with SiO2 layer, the luminous intensity and the compatibility with the rubber matrix increase greatly. Additionally, the luminous intensity increases with the increasing of Eu3+ ions concentration in CaCO3 core and concentration quenching occurs when Eu3+ ions concentration exceeds 7.0 mol%, while it is 5.0 mol% for CaCO3:Eu3+ phosphors. Therefore, preparation of CaCO3:Eu3+@SiO2 phosphors can not only simplify the experimental process through integrating the preparation of CaCO3:Eu3+ and SiO2 layer, but also effectively increase the luminous intensities of CaCO3:Eu3+ phosphors. The as-obtained phosphors may have potential applications in the fields of optical materials and functional polymer composite materials, such as plastics and rubbers.

  11. Ca-site substitution induced a metal-insulator transition in manganite CaMnO3

    International Nuclear Information System (INIS)

    Sousa, D.; Nunes, M.R.; Silveira, C.; Matos, I.; Lopes, A.B.; Melo Jorge, M.E.

    2008-01-01

    A systematic study of the A-site doping in Mn(IV)-rich perovskite manganites Ca 1-x Ho x MnO 3 , over a large homogeneity range (0.1 ≤ x ≤ 0.4), has been performed. A significant increase in the lattice parameters indicated the presence of mixed valence state of Mn: Mn 3+ and Mn 4+ . The substitution of calcium by holmium also induces strong changes in the electrical properties. We found that small Ho concentration produces an important decrease in the electrical resistivity and induces an electrical transition, the temperature corresponding to the metal-insulator transition (T MI ) shifts with the holmium content. This electrical behavior is attributed to the Mn 3+ ions content and a charge order effect

  12. Avaliação dos valores sérico e pleural dos marcadores tumorais CEA, CYFRA21-1 e CA 15-3 em portadores de derrame pleural Evaluation of serum and pleural levels of the tumor markers CEA, CYFRA21-1 and CA 15-3 in patients with pleural effusion

    Directory of Open Access Journals (Sweden)

    Isabella Coimbra Wagner

    2007-04-01

    Full Text Available OBJETIVO: Dosar os marcadores tumorais antígeno carcinoembrionário (CEA, fragmento da citoqueratina 19 (CYFRA21-1 e antígeno glicosídico associado a tumor 15-3 (CA 15-3 em sangue e líquido pleural de portadores de derrames pleurais benignos e malignos, avaliando a sensibilidade de cada um deles nesses fluidos. MÉTODOS: Avaliamos prospectivamente 85 pacientes com derrame pleural. O estudo do líquido pleural obedeceu a critérios determinados pela literatura. A dosagem dos marcadores foi realizada por eletroquimioluminescência. A sensibilidade foi determinada sob a condição de que a especificidade fosse > 90%. RESULTADOS: Foram diagnosticados 36 casos malignos (42,4%, 30 benignos (35,3%; em 19 pacientes (22,3%, o diagnóstico foi inconclusivo. Nos casos malignos, os valores de CEA e CYFRA21-1 foram maiores no líquido pleural do que no sangue, fato não observado para o CA 15-3. Nos casos benignos, os valores do CYFRA21-1 foram maiores no líquido pleural do que no soro, enquanto que para o CEA e o CA 15-3, ocorreu o oposto. Todos os marcadores apresentaram diferença significativa entre os casos malignos e benignos, em líquido pleural e soro. Foi encontrada sensibilidade para CEA, CYFRA21-1 e CA 15-3 no líquido pleural de 69,4%, 69,4% e 66,7%, respectivamente e quando associados, foi 80,6%. No soro, a sensibilidade foi 57,1, 71,4 e 48,6% para CEA, CYFRA21-1 e CA 15-3, respectivamente, e quando associados, foi 77%. CONCLUSÃO: Os resultados sugerem que a utilização desses marcadores pode ser útil na diferenciação entre derrames pleurais malignos e benignos.OBJECTIVE: To determine the levels of the tumor markers carcinoembryonic antigen (CEA, cytokeratin 19 fragment (CYFRA21-1 and carbohydrate antigen 15-3 (CA 15-3 in the blood and pleural fluid of patients with benign or malignant pleural effusion, evaluating the sensitivity of each marker in these fluids. METHODS: We prospectively evaluated 85 patients with pleural effusion. The

  13. Trapping processes in CaS:Eu2+,Tm3+

    International Nuclear Information System (INIS)

    Jia, Dongdong; Jia, Weiyi; Evans, D. R.; Dennis, W. M.; Liu, Huimin; Zhu, Jing; Yen, W. M.

    2000-01-01

    CaS:Eu 2+ ,Tm 3+ is a persistent red phosphor. Thermoluminescence was measured under different excitation and thermal treatment conditions. The results reveal that the charge defects, created by substituting Tm 3+ for Ca 2+ , serve as hole traps for the afterglow at room temperature. Tm 3+ plays the role of deep electron trapping centers, capturing electrons either through the conduction band or directly from the excited Eu 2+ ions. These two processes, in which two different sites of Tm 3+ are involved, correspond to two traps with different depths. (c) 2000 American Institute of Physics

  14. The Pr and Ca Substitution in GdBa2Cu3O7- & delta

    Directory of Open Access Journals (Sweden)

    H. S. H.

    2001-12-01

    Full Text Available   The granular Gd1-x-zPrxCazBa2Cu3O7-δ high-temperature cuprate samples with 0.0 ≤ x ≤ 0.3 and 0.0≤ x ≤ 0.35 are prepared by standard solid state reaction and characterized by XRD and SEM techniques. The BaCuO2 and impurity phases are less than 1% in the samples having high levels of pr and Ca concentrations. The electrical resistivity measurements show a nonlinear reduction in Tc(x,z=etc versus x. Moreover, the Tc(z curve with x=0 is nonlinear and aplateau appears at z≈ 0.05-0.015. For Pr-Ca-doped samples with a constant concentration of Pr, Tc increases with the increase of Ca up to an optimum value of Ca doping and then in decreases. Based on these observations, we suggest that hole filling and hole localization the main effects of Pr ion substiution. The magnetic measurements indicate that the value of Hc1 is in the order of 10 mT. The mangetoresistance measurements have been measured and analyzed. The superconducting transition region is broadened by the application of magnetic field. The experimental data near the onsen of superconductivity are fitted with the Ambegakor and Halperin (AH phase-slip model. We observe that the AH parameter,γ (H, depends not only on the temperature and the magnetic field, but also on the Pr and Ca ions concentrations. It is observed that the critical current density increases with Ca substitution and decreases with Pr substitution in Gd-123 system. We suggest that the Pr ion substitution probably enhances the weak link, but the Ca ion acts as flux pinning center in the GdPrCa-123 system.

  15. Modelling Ca2+ bound Troponin in Excitation Contraction Coupling

    Directory of Open Access Journals (Sweden)

    Henry G. Zot

    2016-09-01

    Full Text Available To explain disparate decay rates of cytosolic Ca2+ and structural changes in the thin filaments during a twitch, we model the time course of Ca2+ bound troponin (Tn resulting from the free Ca2+ transient of fast skeletal muscle. In fibers stretched beyond overlap, the decay of Ca2+ as measured by a change in fluo 3 fluorescence is significantly slower than the intensity decay of the meridional 1/38.5 nm-1 reflection of Tn; this is not simply explained by considering only the Ca2+ binding properties of Tn alone (Matsuo, T., Iwamoto, H., and Yagi, N. (2010. Biophys. J. 99, 193-200. We apply a comprehensive model that includes the known Ca2+ binding properties of Tn in the context of the thin filament with and without cycling crossbridges. Calculations based on the model predict that the transient of Ca2+ bound Tn correlates with either the fluo 3 time course in muscle with overlapping thin and thick filaments or the intensity of the meridional 1/38.5 nm-1 reflection in overstretched muscle. Hence, cycling crossbridges delay the dissociation of Ca2+ from Tn. Correlation with the fluo 3 fluorescence change is not causal given that the transient of Ca2+ bound Tn depends on sarcomere length, whereas the fluo-3 fluorescence change does not. Transient positions of tropomyosin calculated from the time course of Ca2+ bound Tn are in reasonable agreement with the transient of measured perturbations of the Tn repeat in overlap and non-overlap muscle preparations.

  16. Green tide deactivation with layered-structure cuboids of Ag/CaTiO3 under UV light

    International Nuclear Information System (INIS)

    Lee, Soo-Wohn; Lozano-Sánchez, L.M.; Rodríguez-González, V.

    2013-01-01

    Graphical abstract: Synergic reasons such as mass transfer, morphology, biocide properties, UV-A photoresponse, and electron trapping that reduce recombination on Ag/CaTiO 3 nanocomposites, have the potential for the generation of reactive radicals that promote the fatal irreversible deactivation of Tetraselmis suecica algae in 12 min under UV-A irradiation. -- Highlights: • An alternative to deactivate harmful green tide is proposed by employing Ag/CaTiO 3 . • Particles of perovskite-like have rectangular prisms morphology with AgNPs ∼13 nm. • The cuboids achieve complete inactivation of Tetraselmis suecica algae in 12 min. • AgNPs functionalization induce fatal irreversible damages on the algae surface. -- Abstract: In this work, an alternative to deactivate noxious green tide Tetraselmis suecica in the short-term is proposed by employing Perovskite-like cube-shaped, crystalline CaTiO 3 semiconductors functionalized with atomic silver nanoparticles. CaTiO 3 was prepared by a microwave-assisted hydrothermal method and then Ag 0 NPs (1 wt% of CaTiO 3 ), were added by the photoreduction method. The XRD results show that crystalline CaTiO 3 has an orthorhombic unit cell with a Perovskite-like structure. Images obtained by FESEM and HRTEM microscopies show well-faceted CaTiO 3 rectangular prismatic morphology functionalizated with silver nanoparticles ∼13.5 nm. XPS and EDS-FESEM has confirmed the composition of CaTiO 3 and silver occurring mainly as reduced metal. The UV inactivation of noxious T. suecica with Ag/CaTiO 3 nanocomposites formed on bare materials results in complete deactivation of the algae in 12 min. The direct contact between harmful algae and Ag/CaTiO 3 nanocomposite is necessary to deactivate the algae and inhibits algae viability

  17. Absolute Ca Isotopic Measurement Using an Improved Double Spike Technique

    Directory of Open Access Journals (Sweden)

    Jason Jiun-San Shen

    2009-01-01

    Full Text Available A new vector analytical method has been developed in order to obtain the true isotopic composition of the 42Ca-48Ca double spike. This is achieved by using two different sample-spike mixtures combined with the double spike and natural Ca data. Be cause the natural sample (two mixtures and the spike should all lie on a single mixing line, we are able to con strain the true isotopic composition of our double spike using this new approach. Once the isotopic composition of the Ca double spike is established, we are able to obtain the true Ca isotopic composition of the NIST Ca standard SRM915a, 40Ca/44Ca = 46.537 ± 2 (2sm, n = 55, 42Ca/44Ca = 0.31031 ± 1, 43Ca/44Ca = 0.06474 ± 1, and 48Ca/44Ca = 0.08956 ± 1. De spite an off set of 1.3% in 40Ca/44Ca between our result and the previously re ported value (Russell et al. 1978, our data indicate an off set of 1.89__in 40Ca/44Ca between SRM915a and seawater, entirely consistent with the published results.

  18. In vivo behaviors of Ca(OH){sub 2} activated nano SiO{sub 2} (n{sub Ca}/n{sub Si} = 3) cement in rabbit model

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Qing, E-mail: lnqing@yahoo.com [School of Material Engineering, Jinling Institute of Technology, Nanjing 211169 (China); Zhang, Xiaojuan [School of Material Engineering, Jinling Institute of Technology, Nanjing 211169 (China); Lu, Chunhua; Lan, Xianghui [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China); Hou, Guihua [Key Laboratory for Advanced Technology in Environmental Protection of Jiangsu Province, Yancheng Institute of Technology, Yancheng 224051 (China); Xu, Zhongzi [State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009 (China)

    2016-01-01

    In vivo behaviors of Ca(OH){sub 2} activated nano SiO{sub 2} (n{sub Ca}/n{sub Si} = 3, TCS) cement were investigated in the rabbit femoral defects using the poly(methyl methacrylate) (PMMA) as control. The deposited apatite and CaCO{sub 3} layers round TCS paste surfaces were completely used to construct the new bone tissue. TCS paste could stimulate the formation of new bone tissue in marrow tissue. The osteostimulation was mainly attributed to the proliferation and differentiation effects of Ca and Si ions released from TCS paste on the osteoprogenitor cells. However, Calcium–Silicate–Hydrate (C–S–H) gel in TCS paste was harder to degradate than Ca(OH){sub 2}. TCS paste kept the original shape during implantation, and could not provide the pores or spaces for further formation of bone tissue. Osteolytic defects induced by wear particles from TCS paste surface could not be completely avoided, because of the interfacial strain and the extensive micromotion between TCS paste surface and new bone tissue. Overall, our results indicated that Ca(OH){sub 2} activated nano SiO{sub 2} cement was bioactivity and osteostimulation. The further improvements of Ca(OH){sub 2} activated nano SiO{sub 2} cement should be done by achieving a balance between biological properties and mechanical performances. - Highlights: • Ca(OH){sub 2} activated nano SiO{sub 2} (n{sub Ca}/n{sub Si} = 3, TCS) cement was in vivo bioactivity. • Deposited apatite and CaCO{sub 3} particles round TCS paste were utilized to restructure new bone tissue. • TCS paste was able to induce osteogenesis in marrow tissue. • Wear particle could induced osteolytic defect between TCS paste and bone tissue.

  19. Dielectric and piezoelectric properties of sol-gel derived Ca doped PbTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Arun Kumar Singh [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Gupta, Vinay [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)]. E-mail: drvin_gupta@rediffmail.com; Sreenivas, K. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2006-06-15

    Synthesis of Ca doped PbTiO{sub 3} powder by a chemically derived sol-gel process is described. Crystallization characteristics of different compositions Pb{sub 1-x}Ca {sub x}TiO{sub 3} (PCT) with varying calcium (Ca) content in the range x = 0-0.45 has been investigated by DTA/TGA, X-ray diffraction and scanning electron microscopy. The crystallization temperature is found to decrease with increasing calcium content. X-ray diffraction reveals a tetragonal structure for PCT compositions with x {<=} 0.35, and a cubic structure for x = 0.45. Dielectric properties on sintered ceramics prepared with fine sol-gel derived powders have been measured. The dielectric constant is found to increase with increasing Ca content, and the dielectric loss decreases continuously. Sol-gel derived Pb{sub 1-x}Ca {sub x}TiO{sub 3} ceramics with x = 0.45 after poling exhibit infinite electromechanical anisotropy (k {sub t}/k {sub p}) with a high d {sub 33} = 80 pC/N, {epsilon}' = 298 and low dielectric loss (tan {delta} = 0.0041)

  20. Fabrication of superhydrophobic surfaces via CaCO3 mineralization mediated by poly(glutamic acid)

    Science.gov (United States)

    Cao, Heng; Yao, Jinrong; Shao, Zhengzhong

    2013-03-01

    Surfaces with micrometer and nanometer sized hierarchical structures were fabricated by an one-step in situ additive controlled CaCO3 mineralization method. After chemical modification, the surfaces with various morphologies showed superhydrophobicity in different states, which could be easily adjusted by the initial supersaturation of the mineralization solution (concentration of calcium ion and poly(glutamic acid)). Generally, the "lotus state" surface which was covered by a thick layer of tetrahedron-shaped CaCO3 particles to exhibit a contact angle (CA) of 157±1° and a very low contact angle hysteresis (CAH) (roll-off angle=1°) was produced under high supersaturation. On the other hands, the petal-like surface with flower-shaped calcite spherulites was obtained in a relative low supersaturation, which showed both high CA (156±2°) and CAH (180°) in a "Cassie impregnating wetting state".

  1. In situ biosynthesis of bacterial nanocellulose-CaCO3 hybrid bionanocomposite: One-step process

    International Nuclear Information System (INIS)

    Mohammadkazemi, Faranak; Faria, Marisa; Cordeiro, Nereida

    2016-01-01

    In this work, a simple and green route to the synthesis of the bacterial nanocellulose-calcium carbonate (BNC/CaCO 3 ) hybrid bionanocomposites using one-step in situ biosynthesis was studied. The CaCO 3 was incorporated in the bacterial nanocellulose structure during the cellulose biosynthesis by Gluconacetobacter xylinus PTCC 1734 bacteria. Hestrin-Schramm (HS) and Zhou (Z) culture media were used to the hybrid bionanocomposites production and the effect of ethanol addition was investigated. Attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, inverse gas chromatography and thermogravimetric analysis were used to characterize the samples. The experimental results demonstrated that the ethanol and culture medium play an important role in the BNC/CaCO 3 hybrid bionanocomposites production, structure and properties. The BNC/CaCO 3 biosynthesized in Z culture medium revealed higher O/C ratio and amphoteric surface character, which justify the highest CaCO 3 content incorporation. The CaCO 3 was incorporated into the cellulosic matrix decreasing the bacterial nanocellulose crystallinity. This work reveals the high potential of in situ biosynthesis of BNC/CaCO 3 hybrid bionanocomposites and opens a new way to the high value-added applications of bacterial nanocellulose. - Graphical Abstract: Display Omitted - Highlights: • BNC/CaCO 3 hybrid bionanocomposites were produced using in situ biosynthesis process. • Ethanol and culture medium play an important role in the production and properties. • Z-BNC/CaCO 3 bionanocomposites revealed higher O/C ratio and amphoteric surface character. • CaCO 3 incorporated into the BNC decreased crystallinity.

  2. Thermodynamic modeling of the CaO-SiO2-CaCO3-HCaCO2O closed and open system at 25ºC

    Directory of Open Access Journals (Sweden)

    Martínez-Ramírez, S.

    2003-06-01

    Full Text Available This paper reports on a thermodynamic calculation-based study of the CaO-SiOCaCO2-CaCOCaCO3-HCaCO2O closed system at 25 °C, conducted to determine the range of carbonate ion concentrations at which each phase of the system is stable. Portlandite (CH and the CSH gel were found to be stable for carbonate ion concentrations of less than or equal to 7.62 X 10-3 mM/kg and 1.62 x 10-2 mM/kg, respectively. The CSH gel was found to remain stable in the system at pH values ranging from 10.18 to 10.48. In the CaO-SiO2-H2O open system at 25 °C, likewise studied, with PCO2 held constant at atmospheric values, only hydrated silica (SH and calcite were found to be stable.En este trabajo se estudia el sistema CaO2-CaCO3-H2O, cerrado y a 25 ºC a través de cálculos termodinámicos, y se determina el rango de concentración de ion carbonato en el que son estables cada una de las fases del sistema. Se concluye que la portlandita (CH y el gel CSH son estables para concentraciones de ion carbonato iguales o inferiores a 7,62 X 10-3 niM/kg y 1,62 x 10-2 mM/kg respectivamente. El rango de pH en el que el gel CSH es estable en el sistema es 10,18-10,48. También se estudia el sistema CaO-SiO2-H2O a 25 °C, en sistema abierto a PCO2 constante e igual a la de dicho gas en la atmósfera, encontrando que solo la sílice hidratada (SH y la calcita son estables en dicho sistema.

  3. Structure and electrical conduction of the system La sub(1-x)Ca sub(x)FeO sub(3-. cap alpha. )

    Energy Technology Data Exchange (ETDEWEB)

    Hombo, Jukichi; Urabe, Noriake [Kumamoto Univ. (Japan). Faculty of Engineering; Hiroshige, Gota; Hamada, Kotaro

    1982-08-01

    Perovskite phases in the system, La sub(1-x)Ca sub(x)FeO sub(3-..cap alpha..) were prepared with La/sub 2/O/sub 3/, CaCO/sub 3/, and Fe/sub 2/O/sub 3/ by firing in air and in vacuo. The compositions of samples fired in vacuo and in air are represented as La sub(1-x)Ca sub(x)FeO sub(3-x 2) and La sub(1-x)Ca sub(x)Fe sub(1-y)sup(3+)Fe sub(y)sup(4+)O sub(3-x/2+y/2), respectively. That is, samples fired in vacuo contain some oxygen vacancies and no tetravalent iron; in contrast, samples fired in air contain both oxygen vacancies and tetravalent iron in the structures. The electrical conductivities of these synthesized oxides depended extensively upon the content of tetravalent iron. For instance, the conductivity of the sample x = 0.6 fired in air was larger by 10/sup 6/ than that of the sample fired in vacuo. In this system, except for the two terminal compositions of x = 0 and x = 1.0, the values of activation energy for conduction are considerably small, and from the results of thermo-electromotive force measurement, the charge carrier was positive. Furthermore, the conductivity increased somewhat with time during the conductivity measurement by the direct-current method. These facts suggest that the electric conduction would not be ionic but electronic. The electrical conduction would then be carried out by the so-called hopping mechanism by which the positive charge is transferred.

  4. Systems of Ba(PO3)2-Sr(Pu3)2, Cd(PO3)2-Ca(PO3)2

    International Nuclear Information System (INIS)

    Tokman, I.A.; Bukhalova, G.A.

    1977-01-01

    Phase diagrams of the Ba(PO 3 ) 2 -Sr(PO 3 ) 2 and Cd(PO 3 ) 2 -Ca(PO 3 ) 2 systems have been studied and plotted by the methods of differential-thermal analysis (DTA), visual-polythermal, X-ray phase and infrared spectroscopy. The Ba(PO 3 ) 2 -Sr(PO 3 ) 2 system is of the eutectic type. In the binary system Cd(PO 3 ) 2 -Ca(PO 3 ) 2 the existence of a continuous series of solid solutions with a minimum at 858 deg C and 27.5 mol.% Ca(PO 3 ) 2 has been established

  5. Synthesis of Al₂Ca Dispersoids by Powder Metallurgy Using a Mg-Al Alloy and CaO Particles.

    Science.gov (United States)

    Fujita, Junji; Umeda, Junko; Kondoh, Katsuyoshi

    2017-06-28

    The elemental mixture of Mg-6 wt %Al-1 wt %Zn-0.3 wt %Mn (AZ61B) alloy powder and CaO particles was consolidated by an equal-channel angular bulk mechanical alloying (ECABMA) process to form a composite precursor. Subsequently, the precursor was subjected to a heat treatment to synthesize fine Al₂Ca particles via a solid-state reaction between the Mg-Al matrix and CaO additives. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS) and electron probe micro-analysis on the precursor indicated that 4.7-at % Al atoms formed a supersaturated solid solution in the α-Mg matrix. Transmission electron microscopy-EDS and X-ray diffraction analyses on the AZ61B composite precursor with 10-vol % CaO particles obtained by heat treatment confirmed that CaO additives were thermally decomposed in the Mg-Al alloy, and the solid-soluted Ca atoms diffused along the α-Mg grain boundaries. Al atoms also diffused to the grain boundaries because of attraction to the Ca atoms resulting from a strong reactivity between Al and Ca. As a result, needle-like (Mg,Al)₂Ca intermetallics were formed as intermediate precipitates in the initial reaction stage during the heat treatment. Finally, the precipitates were transformed into spherical Al₂Ca particles by the substitution of Al atoms for Mg atoms in (Mg,Al)₂Ca after a long heat treatment.

  6. Oestrogen directly inhibits the cardiovascular L-type Ca2+ channel Cav1.2

    International Nuclear Information System (INIS)

    Ullrich, Nina D.; Koschak, Alexandra; MacLeod, Kenneth T.

    2007-01-01

    Oestrogen can modify the contractile function of vascular smooth muscle and cardiomyocytes. The negative inotropic actions of oestrogen on the heart and coronary vasculature appear to be mediated by L-type Ca 2+ channel (Ca v 1.2) inhibition, but the underlying mechanisms remain elusive. We tested the hypothesis that oestrogen directly inhibits the cardiovascular L-type Ca 2+ current, I CaL . The effect of oestrogen on I CaL was measured in Ca v 1.2-transfected HEK-293 cells using the whole-cell patch-clamp technique. The current revealed typical activation and inactivation profiles of nifedipine- and cadmium-sensitive I CaL . Oestrogen (50 μM) rapidly reduced I CaL by 50% and shifted voltage-dependent activation and availability to more negative potentials. Furthermore, oestrogen blocked the Ca 2+ channel in a rate-dependent way, exhibiting higher efficiency of block at higher stimulation frequencies. Our data suggest that oestrogen inhibits I CaL through direct interaction of the steroid with the channel protein

  7. The race to learn: spike timing and STDP can coordinate learning and recall in CA3.

    Science.gov (United States)

    Nolan, Christopher R; Wyeth, Gordon; Milford, Michael; Wiles, Janet

    2011-06-01

    The CA3 region of the hippocampus has long been proposed as an autoassociative network performing pattern completion on known inputs. The dentate gyrus (DG) region is often proposed as a network performing the complementary function of pattern separation. Neural models of pattern completion and separation generally designate explicit learning phases to encode new information and assume an ideal fixed threshold at which to stop learning new patterns and begin recalling known patterns. Memory systems are significantly more complex in practice, with the degree of memory recall depending on context-specific goals. Here, we present our spike-timing separation and completion (STSC) model of the entorhinal cortex (EC), DG, and CA3 network, ascribing to each region a role similar to that in existing models but adding a temporal dimension by using a spiking neural network. Simulation results demonstrate that (a) spike-timing dependent plasticity in the EC-CA3 synapses provides a pattern completion ability without recurrent CA3 connections, (b) the race between activation of CA3 cells via EC-CA3 synapses and activation of the same cells via DG-CA3 synapses distinguishes novel from known inputs, and (c) modulation of the EC-CA3 synapses adjusts the learned versus test input similarity required to evoke a direct CA3 response prior to any DG activity, thereby adjusting the pattern completion threshold. These mechanisms suggest that spike timing can arbitrate between learning and recall based on the novelty of each individual input, ensuring control of the learn-recall decision resides in the same subsystem as the learned memories themselves. The proposed modulatory signal does not override this decision but biases the system toward either learning or recall. The model provides an explanation for empirical observations that a reduction in novelty produces a corresponding reduction in the latency of responses in CA3 and CA1. Copyright © 2010 Wiley-Liss, Inc.

  8. Ceramic powders of CaZrO3. Preparation and sintering

    International Nuclear Information System (INIS)

    Tamborenea, S.; Coronel, A.; Mazzoni, A.D.; Aglietti, E.F.

    2003-01-01

    Calcium zirconate (CaZrO 3 ) is a compound belonging to the perovskite family of the A 2+ B 4+ O 3 6- type with orthorhombic crystalline structure (distorted perovskite).CaZrO 3 is used in the manufacture of sensors of oxygen, humidity, hydrogen and hydrocarbides.Additionally, it is also being studied for the manufacture of thermistors.The calcium zirconate preparation by solid state reaction from stoichiometric mixtures of CaCO 3 and ZrO 2 is studied.The formation reaction was followed by thermal analysis techniques (DTA-TG-DTG) and X-ray diffraction (XRD).The different behaviour of the mixtures was studied according to the milling type employed.It could be observed a shift of some peaks, mainly of TG (gravimetry) with a tendency to a temperature decrease.These changes are mainly influenced by the amorphization effects on the carbonate and by the mixing caused by the milling type used.The powder (CaZrO 3 ) was isostatically pressed obtaining then green densities of 50% of the theoretical one.Sintering was made in air between 1300 and 1600degC at times between 0 and 240.Densities reached were between 90 and 95% increasing with the temperature and the sintering time

  9. Trivial topological phase of CaAgP and the topological nodal-line transition in CaAg (P1 -xA sx)

    Science.gov (United States)

    Xu, N.; Qian, Y. T.; Wu, Q. S.; Autès, G.; Matt, C. E.; Lv, B. Q.; Yao, M. Y.; Strocov, V. N.; Pomjakushina, E.; Conder, K.; Plumb, N. C.; Radovic, M.; Yazyev, O. V.; Qian, T.; Ding, H.; Mesot, J.; Shi, M.

    2018-04-01

    By performing angle-resolved photoemission spectroscopy and first-principles calculations, we address the topological phase of CaAgP and investigate the topological phase transition in CaAg (P1 -xA sx) . We reveal that in CaAgP, the bulk band gap and surface states with a large bandwidth are topologically trivial, in agreement with hybrid density functional theory calculations. The calculations also indicate that application of "negative" hydrostatic pressure can transform trivial semiconducting CaAgP into an ideal topological nodal-line semimetal phase. The topological transition can be realized by partial isovalent P/As substitution at x =0.38 .

  10. Tumor markers CA19-9, CA242 and CEA in the diagnosis of pancreatic cancer: a meta-analysis.

    Science.gov (United States)

    Zhang, Yimin; Yang, Jun; Li, Hongjuan; Wu, Yihua; Zhang, Honghe; Chen, Wenhu

    2015-01-01

    Pancreatic cancer has the worst prognosis and early detection is crucial for improving patient prognosis. Therefore, we performed a meta-analysis to evaluate and compare the sensitivity and specificity of single test of CA19-9, CA242, and CEA, as well as combination test in pancreatic cancer detection. We searched PubMed, Embase, Medline, and Wanfang databases for studies that evaluated the diagnostic validity of CA19-9, CA242, and CEA between January 1990 and September 2014. Data were analyzed by Meta-Disc and STATA software. A total of 21 studies including 3497 participants, which fulfilled the inclusion criteria were considered for analysis. The pooled sensitivities for CA19-9, CA242, and CEA were 75.4 (95% CI: 73.4-77.4), 67.8 (95% CI: 65.5-70), and 39.5 (95% CI: 37.3-41.7), respectively. The pooled specificities of CA19-9, CA242, and CEA were 77.6 (95% CI: 75.4-79.7), 83 (95% CI: 81-85), and 81.3 (95% CI: 79.3-83.2), respectively. Parallel combination of CA19-9+CA242 has a higher sensitivity (89, 95% CI: 80-95) without impairing the specificity (75, 95% CI: 67-82). Our meta-analysis showed that CA242 and CA19-9 have better performance in the diagnosis of pancreatic cancer than CEA. Furthermore, parallel combination test of CA19-9+CA242 could be of better diagnostic value than individual CA242 or CA19-9 test.

  11. Human limbic encephalitis serum enhances hippocampal mossy fiber-CA3 pyramidal cell synaptic transmission.

    Science.gov (United States)

    Lalic, Tatjana; Pettingill, Philippa; Vincent, Angela; Capogna, Marco

    2011-01-01

    Limbic encephalitis (LE) is a central nervous system (CNS) disease characterized by subacute onset of memory loss and epileptic seizures. A well-recognized form of LE is associated with voltage-gated potassium channel complex antibodies (VGKC-Abs) in the patients' sera. We aimed to test the hypothesis that purified immunoglobulin G (IgG) from a VGKC-Ab LE serum would excite hippocampal CA3 pyramidal cells by reducing VGKC function at mossy-fiber (MF)-CA3 pyramidal cell synapses. We compared the effects of LE and healthy control IgG by whole-cell patch-clamp and extracellular recordings from CA3 pyramidal cells of rat hippocampal acute slices. We found that the LE IgG induced epileptiform activity at a population level, since synaptic stimulation elicited multiple population spikes extracellularly recorded in the CA3 area. Moreover, the LE IgG increased the rate of tonic firing and strengthened the MF-evoked synaptic responses. The synaptic failure of evoked excitatory postsynaptic currents (EPSCs) was significantly lower in the presence of the LE IgG compared to the control IgG. This suggests that the LE IgG increased the release probability on MF-CA3 pyramidal cell synapses compared to the control IgG. Interestingly, α-dendrotoxin (120 nm), a selective Kv1.1, 1.2, and 1.6 subunit antagonist of VGKC, mimicked the LE IgG-mediated effects. This is the first functional demonstration that LE IgGs reduce VGKC function at CNS synapses and increase cell excitability. Wiley Periodicals, Inc. © 2010 International League Against Epilepsy.

  12. Atomic structure of CaF2/MnF2-Si(1 1 1) superlattices from X-ray diffraction

    International Nuclear Information System (INIS)

    Alcock, Simon G.; Nicklin, C.L.; Howes, P.B.; Norris, C.A.; Kyutt, R.N.; Sokolov, N.S.; Yakovlev, N.L.

    2007-01-01

    X-ray reflectivity and non-specular crystal truncation rod scans have been used to determine the three-dimensional atomic structure of the buried CaF 2 -Si(1 1 1) interface and ultrathin films of MnF 2 and CaF 2 within a superlattice. We show that ultrathin films of MnF 2 , below a critical thickness of approximately four monolayers, are crystalline, pseudomorphic, and adopt the fluorite structure of CaF 2 . High temperature deposition of the CaF 2 buffer layer produces a fully reacted, CaF 2 -Si(1 1 1) type-B interface. The mature, 'long' interface is shown to consist of a partially occupied layer of CaF bonded to the Si substrate, followed by a distorted CaF layer. Our atomistic, semi-kinematical scattering method extends the slab reflectivity method by providing in-plane structural information

  13. Structure and magnetic properties of La{sub 2/3}Sr{sub 1/3}MnO{sub 3}/CaMnO{sub 3} multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Granada, Mara [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina)]. E-mail: granadam@cab.cnea.gov.ar; Sirena, Martin [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Steren, Laura B. [Centro Atomico Bariloche and Instituto Balseiro, CNEA-UNC, Av. Bustillo 9500, 8400 San Carlos de Bariloche (Argentina); Leyva, Gabriela [Depto. de Fisica, Centro Atomico Constituyentes, CNEA, Av. Gral. Paz y Constituyentes, 1650 San Martin (Argentina)

    2004-12-31

    Structural and magnetic properties of manganite-based multilayers, La{sub 2/3}Sr{sub 1/3}MnO{sub 3}/CaMnO{sub 3}, composed of ferromagnetic metals and antiferromagnetic insulator barriers are investigated in this work. Compounds of similar lattice parameters were used to build the samples, so we expect an excellent stacking of the different layers along the structure. To get a first insight of this system, the crystalline structure of a series of samples, grown on (1 0 0) SrTiO{sub 3} and (1 0 0) MgO single-crystalline substrates, has been studied. X-ray diffraction patterns show that the structure is strongly textured in the (1 0 0) direction when grown on SrTiO{sub 3}, regardless the composition of the bottom layer. A different result is found on the same system grown on MgO: when the buffer layer is CaMnO{sub 3}, the structure grows in the (1 1 0) orientation while it grows in the (1 0 0) direction when the bottom layer is La{sub 2/3}Sr{sub 1/3}MnO{sub 3}. Magnetic coupling of the ferromagnetic layers across the antiferromagnetic spacer has been studied with magnetization measurements.

  14. Reduced endogenous Ca2+ buffering speeds active zone Ca2+ signaling.

    Science.gov (United States)

    Delvendahl, Igor; Jablonski, Lukasz; Baade, Carolin; Matveev, Victor; Neher, Erwin; Hallermann, Stefan

    2015-06-09

    Fast synchronous neurotransmitter release at the presynaptic active zone is triggered by local Ca(2+) signals, which are confined in their spatiotemporal extent by endogenous Ca(2+) buffers. However, it remains elusive how rapid and reliable Ca(2+) signaling can be sustained during repetitive release. Here, we established quantitative two-photon Ca(2+) imaging in cerebellar mossy fiber boutons, which fire at exceptionally high rates. We show that endogenous fixed buffers have a surprisingly low Ca(2+)-binding ratio (∼ 15) and low affinity, whereas mobile buffers have high affinity. Experimentally constrained modeling revealed that the low endogenous buffering promotes fast clearance of Ca(2+) from the active zone during repetitive firing. Measuring Ca(2+) signals at different distances from active zones with ultra-high-resolution confirmed our model predictions. Our results lead to the concept that reduced Ca(2+) buffering enables fast active zone Ca(2+) signaling, suggesting that the strength of endogenous Ca(2+) buffering limits the rate of synchronous synaptic transmission.

  15. Contextual Learning Requires Functional Diversity at Excitatory and Inhibitory Synapses onto CA1 Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Dai Mitsushima

    2015-01-01

    Full Text Available Although the hippocampus is processing temporal and spatial information in particular context, the encoding rule creating memory is completely unknown. To examine the mechanism, we trained rats on an inhibitory avoidance (IA task, a hippocampus-dependent rapid one-trial contextual learning paradigm. By combining Herpes virus-mediated in vivo gene delivery with in vitro patch-clamp recordings, I reported contextual learning drives GluR1-containing AMPA receptors into CA3-CA1 synapses. The molecular event is required for contextual memory, since bilateral expression of delivery blocker in CA1 successfully blocked IA learning. Moreover, I found a logarithmic correlation between the number of delivery blocking cells and learning performance. Considering that one all-or-none device can process 1-bit of data per clock (Nobert Wiener 1961, the logarithmic correlation may provides evidence that CA1 neurons transmit essential data of contextual information. Further, I recently reported critical role of acetylcholine as an intrinsic trigger of learning-dependent synaptic plasticity. IA training induced ACh release in CA1 that strengthened not only AMPA receptor-mediated excitatory synapses, but also GABAA receptor-mediated inhibitory synapses on each CA1 neuron. More importantly, IA-trained rats showed individually different excitatory and inhibitory synaptic inputs with wide variation on each CA1 neuron. Here I propose a new hypothesis that the diversity of synaptic inputs on CA1 neurons may depict cell-specific outputs processing experienced episodes after training.

  16. Calcium binding properties of calcium dependent protein kinase 1 (CaCDPK1) from Cicer arietinum.

    Science.gov (United States)

    Dixit, Ajay Kumar; Jayabaskaran, Chelliah

    2015-05-01

    Calcium plays a crucial role as a secondary messenger in all aspects of plant growth, development and survival. Calcium dependent protein kinases (CDPKs) are the major calcium decoders, which couple the changes in calcium level to an appropriate physiological response. The mechanism by which calcium regulates CDPK protein is not well understood. In this study, we investigated the interactions of Ca(2+) ions with the CDPK1 isoform of Cicer arietinum (CaCDPK1) using a combination of biophysical tools. CaCDPK1 has four different EF hands as predicted by protein sequence analysis. The fluorescence emission spectrum of CaCDPK1 showed quenching with a 5 nm red shift upon addition of calcium, indicating conformational changes in the tertiary structure. The plot of changes in intensity against calcium concentrations showed a biphasic curve with binding constants of 1.29 μM and 120 μM indicating two kinds of binding sites. Isothermal calorimetric (ITC) titration with CaCl2 also showed a biphasic curve with two binding constants of 0.027 μM and 1.7 μM. Circular dichroism (CD) spectra showed two prominent peaks at 208 and 222 nm indicating that CaCDPK1 is a α-helical rich protein. Calcium binding further increased the α-helical content of CaCDPK1 from 75 to 81%. Addition of calcium to CaCDPK1 also increased fluorescence of 8-anilinonaphthalene-1-sulfonic acid (ANS) indicating exposure of hydrophobic surfaces. Thus, on the whole this study provides evidence for calcium induced conformational changes, exposure of hydrophobic surfaces and heterogeneity of EF hands in CaCDPK1. Copyright © 2015 Elsevier GmbH. All rights reserved.

  17. New limits on 2β processes in 40Ca and 46Ca by using low radioactive CaF2(Eu) crystal scintillators

    International Nuclear Information System (INIS)

    Belli, P.; Bernabei, R.; Dai, C.J.

    2001-01-01

    The development of highly radiopure CaF 2 (Eu) crystal scintillators has been performed aiming at a substantial sensitivity enhancement of the 2β decay investigation and of the search for dark matter particles with spin-dependent (SD) interaction. The results of CaF 2 (Eu) background measurements and simulation are presented. New and highly improved T 1/2 limits on the 2β decay of 46 Ca and the double electron capture of 40 Ca are obtained

  18. Luminescent properties of Mg3Ca3(PO4)4: Eu2+ blue-emitting phosphor for white light emitting diodes

    International Nuclear Information System (INIS)

    Li Yinqun; Deng Degang; Wang Qian; Li Gaofeng; Hua Youjie; Jia Guohua; Huang Lihui; Zhao Shilong; Wang Huanping; Li Chenxia; Xu Shiqing

    2012-01-01

    A blue-emitting phosphor, Eu 2+ -activated Mg 3 Ca 3 (PO 4 ) 4 phosphor was synthesized by conventional solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the phase formation. Photoluminescence (PL) results showed that Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ could be efficiently excited by UV–visible light from 250 to 430 nm, which matched well with the emission wavelengths of near-UV and UV LED chips. The effects of the doped-Eu 2+ concentration in Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ on the PL were also investigated. The result reveals that Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ is a potential blue-emitting phosphor for white LEDs. - Graphical Abstract: The excitation spectra show a broad peak from 250 to 430 nm, which means Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor can be suitable for application in white LEDs excited by the near-UV and UV LEDs. The emission spectrum peaked at 456 nm with the full-width half-maximum (FWHM) of 102 nm is attributed to the 4f 6 5d 1 –4f 7 transition of the Eu 2+ ion. The asymmetric emission spectra show that Eu 2+ has more one emission center in Mg 3 Ca 3 (PO 4 ) 4 , which can be deconvoluted into at least four Gaussian components peaked at 423, 446, 483 and 510 nm. Highlights: ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor could be effectively excited by UV chips (360–430 nm). ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor is a potential blue-emitting phosphor for white LEDs. ► Mg 3 Ca 3 (PO 4 ) 4 : Eu 2+ phosphor shows a broadband emission.

  19. Kinetic and equilibrium properties of regulatory Ca(2+)-binding domains in sodium-calcium exchangers 2 and 3.

    Science.gov (United States)

    Tal, Inbal; Kozlovsky, Tom; Brisker, Dafna; Giladi, Moshe; Khananshvili, Daniel

    2016-04-01

    In mammals, three sodium-calcium exchanger (NCX) protein isoforms (NCX1, NCX2, and NCX3) mediate Ca(2+) fluxes across the membrane to maintain cellular Ca(2+) homeostasis. NCX isoforms and their splice variants are expressed in a tissue-specific manner to meet physiological demands. NCX1 is ubiquitously expressed, NCX2 is expressed in the brain and spinal cord, and NCX3 is expressed in the brain and skeletal muscle. Eukaryotic NCXs contain two cytosolic regulatory Ca(2+)-binding domains, CBD1 and CBD2, which form a two-domain tandem (CBD12) through a short linker. Ca(2+) binding to the CBDs underlies allosteric regulation of NCX. Previous structural and functional studies in NCX1 have shown that the CBDs synergistically interact, where their interactions are modulated in a splice variant-specific manner by splicing segment at CBD2. Here, we analyze the equilibrium and kinetic properties of Ca(2+) binding to purified preparations of CBD1, CBD2, and CBD12 from NCX2 and from NCX3 splice variants. We show that CBD1 interacts with CBD2 in the context of the CBD12 tandem in all NCX isoforms, where these interactions specifically modulate Ca(2+) sensing at the primary sensor of CBD1 to meet the physiological requirements. For example, the rate-limiting slow dissociation of "occluded" Ca(2+) from the primary allosteric sensor of variants expressed in skeletal muscle is ∼10-fold slower than that of variants expressed in the brain. Notably, these kinetic differences between NCX variants occur while maintaining a similar Ca(2+) affinity of the primary sensor, since the resting [Ca(2+)]i levels are similar among different cell types. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Efectos Estructurales y de Interfase en Capas Finas de La(2/3)Ca(1/3)MnO(3)

    OpenAIRE

    Abad Muñoz, Libertad

    2007-01-01

    En el desarrollo de esta tesis hemos analizado distintos aspectos preliminares relacionados con la utilización de óxidos complejos, tales como las perovskitas de manganeso, en la implementación de dispositivos con potenciales aplicaciones en magnetoelectrónica. En concreto, hemos abordado a fondo distintos aspectos relacionados con la fabricación de uniones túnel magnéticas basadas en el sistema La2/3Ca1/3MnO3 (LCMO)/SrTiO3 (STO).Nuestro trabajo ha puesto de manifiesto que la técnica de pulve...

  1. Preparation and tunable luminescence of CaCO{sub 3}: Eu{sup 3+}, Tb{sup 3+} phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Qijun; Dong, Yanwei; Kang, Ming, E-mail: dyw510@126.com; Zhang, Ping

    2014-12-15

    Luminescent tunable phosphors CaCO{sub 3}: Eu{sup 3+}, Tb{sup 3+} were synthesized by a microwave co-precipitation method. The structure and micro-morphology of samples were characterized and analyzed by an X-ray powder diffraction (XRD) and a scanning electronic microscope (SEM), results showed that Tb{sup 3+} and Eu{sup 3+} ions were uniformly introduced into the host lattice of CaCO{sub 3} entering substitutionally in Ca{sup 2+} sites. The photoluminescence (PL) properties were characterized by PL, PL excitation spectroscopy and chromaticity coordinates. Under the excitation at 235 nm and 267 nm, the transitions of {sup 5}D{sub 4}→{sup 7}F{sub J} (J=3–6) for Tb{sup 3+} and {sup 5}D{sub 0}→{sup 7}F{sub J} (J=0–3) for Eu{sup 3+} were observed, and the luminescent intensities and emitting colors of Eu{sup 3+}–Tb{sup 3+} co-doped CaCO{sub 3} phosphors could be gradually changed between red and green by changing the Eu/Tb atomic ratio and the excitation wavelength. - highlights: • A new phosphor CaCO{sub 3}: Eu{sup 3+}, Tb{sup 3+} was prepared by the microwave co-precipitation method. • The phosphors exhibited green and red color under UV excitation. • The emission color could be gradually tuned between green and red. • The phosphors had the potential as materials for anti-counterfeiting technologies.

  2. The crystal structure of galgenbergite-(Ce), CaCe2(CO3)4•H2O

    Science.gov (United States)

    Walter, Franz; Bojar, Hans-Peter; Hollerer, Christine E.; Mereiter, Kurt

    2013-04-01

    Galgenbergite-(Ce) from the type locality, the railroad tunnel Galgenberg between Leoben and St. Michael, Styria, Austria, was investigated. There it occurs in small fissures of an albite-chlorite schist as very thin tabular crystals building rosette-shaped aggregates associated with siderite, ancylite-(Ce), pyrite and calcite. Electron microprobe analyses gave CaO 9.49, Ce2O3 28.95, La2O3 11.70, Nd2O3 11.86, Pr2O3 3.48, CO2 30.00, H2O 3.07, total 98.55 wt.%. CO2 and H2O calculated by stoichiometry. The empirical formula (based on Ca + REE ∑3.0) is C{{a}_{1.00 }}{{( {C{{e}_{1.04 }}L{{a}_{0.42 }}N{{d}_{0.42 }}P{{r}_{0.12 }}} )}_{2.00 }}{{( {C{{O}_3}} )}_4}\\cdot {{H}_2}O , and the simplified formula is CaC{{e}_2}{{( {C{{O}_3}} )}_4}\\cdot {{H}_2}O . According to X-ray single crystal diffraction galgenbergite-(Ce) is triclinic, space group Poverline{1},a=6.3916(5) , b = 6.4005(4), c = 12.3898(9) Å, α = 100.884(4), β = 96.525(4), γ = 100.492(4)°, V = 483.64(6) Å3, Z = 2. The eight strongest lines in the powder X-ray diffraction pattern are [ d calc in Å/( I)/ hkl]: 5.052/(100)/011; 3.011/(70)/0-22; 3.006/(66)/004; 5.899/(59)/-101; 3.900/(51)/1-12; 3.125/(46)/-201; 2.526/(42)/022; 4.694/(38)/-102. The infrared absorption spectrum reveals H2O (OH-stretching mode at 3,489 cm-1, HOH bending mode at 1,607 cm-1) and indicates the presence of distinctly non-equivalent CO3-groups by double and quadruple peaks of their ν1, ν2, ν3 and ν4 modes. The crystal structure of galgenbergite-(Ce) was refined with X-ray single crystal data to R1 = 0.019 for 2,448 unique reflections ( I > 2 σ( I)) and 193 parameters. The three cation sites of the structure Ca(1), Ce(2) and Ce(3) have a modest mixed site occupation by Ca and small amount of REE (Ce, La, Pr, Nd) and vice versa. The structure is based on double layers parallel to (001), which are composed of Ca(1)Ce(2)(CO3)2 single layers with an ordered chessboard like arrangement of Ca and Ce, and with a roof tile

  3. Clinical evaluation of CEA, CA19-9, CA72-4 and CA125 in gastric cancer patients with neoadjuvant chemotherapy.

    Science.gov (United States)

    Sun, Zhipeng; Zhang, Nengwei

    2014-12-29

    In the clinical practice of neoadjuvant chemotherapy, response markers are very important. We aimed o investigate whether tumor markers CEA(carcino-embryonic antigen), CA19-9(carbohydrate antigen 19-9), CA72-4(carbohydrate antigen 72-4), and CA125(carbohydrate antigen 125) can be used to evaluate the response to neoadjuvant chemotherapy, and to evaluate the diagnosis and prognosis value of four tumor markers in the patients of gastric cancer. A retrospective review was performed of 184 gastric cancer patients who underwent a 5-Fu, leucovorin, and oxaliplatin (FOLFOX) neoadjuvant chemotherapy regimen, followed by surgical treatment. Blood samples for CEA, CA19-9, CA72-4, and CA125 levels were taken from patients upon admission to the hospital and after neoadjuvant chemotherapy. Statistical analysis was performed to identify the clinical value of these tumor markers in predicting the survival and the response to neoadjuvant chemotherapy. Median overall survival times of pretreatment CA19-9-positive and CA72-4-positive patients (14.0 +/-2.8 months and 14.8 +/-4.0 months, respectively) were significantly less than negative patients (32.5 +/-8.9 months and 34.0 +/-10.1 months, respectively) (P = 0.000 and P = 0.002, respectively). Pretreatment status of CA19-9 and CA72-4 were independent prognostic factors in gastric cancer patients (P = 0.029 and P = 0.008, respectively). Pretreatment CEA >50 ng/ml had a positive prediction value for clinical disease progression after neoadjuvant chemotherapy according to the ROC curve (AUC: 0.694, 95% CI: 0.517 to 0.871, P = 0.017). The decrease of tumor markers CEA, CA72-4, and CA125 was significant after neoadjuvant chemotherapy (P = 0.030, P = 0.010, and P = 0.009, respectively), especially in patients with disease control (including complete, partial clinical response, and stable disease) (P = 0.012, P = 0.020, and P = 0.025, respectively). A decrease in CA72-4 by more than 70% had

  4. Search for the 3-phonon state of 40Ca

    International Nuclear Information System (INIS)

    Fallot, M.

    2002-09-01

    We study collective vibrational states of the nucleus: giant resonances and multiphonon states. It has been shown that multiphonon states, which are built with several superimposed giant resonances, can be excited in inelastic heavy ion scattering near the grazing angle. No three photon states have been observed until now. An experiment has been performed at GANIL, aiming at the observation of the 3-phonon state built with the giant quadrupole resonance (GQR) in 40 Ca, with the reaction 40 Ca + 40 Ca at 50 A.Me.V. The ejectile was identified in the SPEG spectrometer. Light charged particles were detected in 240 CsI scintillators of the INDRA 4π array. The analysis confirms the previous results about the GQR and the 2-phonon state in 40 Ca. For the first time, we have measured an important direct decay branch of the GQR by alpha particles. Applying the so-called 'missing energy method' to events containing three protons measured in coincidence with the ejectile, we observe a direct decay branch revealing the presence of a 3-phonon state in the excitation energy region expected for the triple GQR. Dynamical processes are also studied in the inelastic channel, emphasizing a recently discovered mechanism named towing-mode. We observe for the first time the towing-mode of alpha particles. The energies of multiphonon states in 40 Ca and 208 Pb have been computed microscopically including some anharmonicities via boson mapping methods. The basis of the calculation has been extended to the 3-phonon states. Our results show large anharmonicities (several MeV), due to the coupling of 3-phonon states to 2-phonon states. The extension of the basis to 4-phonon states has been performed for the first time. The inclusion of the 4 phonon states in the calculation did not affect the previous observations concerning the 2-phonon states. Preliminary results on the anharmonicities of the 3-phonon states are presented. (author)

  5. CaCO{sub 3} scaling in pressure retarded osmosis

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Willy; Holt, Torleif; Sivertsen, Edvard

    2010-07-01

    Full text: Osmotic power is a renewable energy source exploiting the energy of mixing between freshwater and seawater. Pressure retarded osmosis (PRO) is one of the methods that is technically feasible to extract this energy. In PRO, freshwater and seawater are separated by a semi permeable membrane that ideally only will allow transport of water, whereas salts and dissolved constituents will be retained by the membrane. Due to the difference in osmotic pressure across the membrane, there will be an osmotic transport of water from the freshwater side to the seawater side of the membrane. The osmotic transport of water will take place against a pressure gradient equal to approximately half the osmotic pressure between the two solutions. The resulting net volume increase on the seawater side will be utilised to drive a turbine. One of the major challenges towards realisation of osmotic power as a commercially feasible renewable energy source will be to maintain stable performance of the PRO membranes over time. In this respect the control of membrane fouling and scaling will be essential. Both adequate pre-treatment, in order to reduce the fouling potential of incoming feed waters, and operation and maintenance aspects such as flux control, disinfection and suitable membrane cleaning procedures will be important. A study investigating the CaCO{sub 3} scaling potential in PRO has been accomplished. Laboratory experiments with model solutions having different saturation index (SI) with respect to CaCO{sub 3} have been performed, and the flux decline over time due to precipitation of CaCO{sub 3} scale was monitored. A transport model estimating the concentration of Ca{sup 2+} and CO{sub 3}{sup 2-} at the membrane surface was developed and used to determine the SI for each of the experiments. Further, the SI of CaCO{sub 3} for a selection of 32 Norwegian rivers were calculated and for all cases the SI at the membrane surface was simulated for operation in PRO. (Author)

  6. Nuclear spectroscopy of Ca and Sc isotopes from inelastic scattering and one-nucleon transfer reactions on a radioactive 41Ca target

    International Nuclear Information System (INIS)

    Vold, P.

    1978-04-01

    The structure of energy levels in 40 , 42 Ca and 42 Sc has been studied using inelastic proton scattering and one-nucleon stripping and pick-up transfer reactions on a 41 Ca target. Data has given the following information on the properties of the 41 Ca ground state wave function; i) the 41 Ca (g.s.) looks very much like an f (sub7/2) neutron coupled to the 40 Ca (g.s.) core. ii) The core-excited component of the 41 Ca (g.s.) is determined to be 10 or less. It was inferred that the main constituents of the spectroscopic strength leading to the (f(sub7/2)) 2 , (f(sub7/2)p(sub3/2))(subt=1) and (f(sub7/2)p(sub1/2))(subT=1) configurations have been identified. This was used to deduce the effective two-particle matrix elements for these configurations. The 42 Sc and 42 Ca data result in excellent agreement for the T=1 members of the (f(sub7/2)) 2 multiplet while the (f(sub7/2)p(sub3/2))(subT=1) matrix elements derived from the 42 Sc data are about 0.2 MeV more repulsive than those obtained from the 42 Ca data. The (f(sub7/2)d(sub3/2) -1 ) matrix elements derived from the present ( 3 He,α) data were compared to the corresponding values obtained from one-nucleon stripping to mass 34 nuclei. The two sets of matrix elements are in very good agreement. The 40 Ca values are also well reproduced by calculations using the modified surface delta interaction. The experimental spectroscopic factors to both the T=0 and T=1 states of the (f(sub7/2)) 2 multiplet are in remarkably good agreement with the predicted values of the coexistence model considering the simplicity of this model. (JIW)

  7. Preparation of CaTiO3 Asymmetric Membranes Using Polyetherimide as Binder Polymer

    Directory of Open Access Journals (Sweden)

    Endang Purwanti Setyaningsih

    2016-03-01

    Full Text Available Asymmetric dense and thin membranes have been prepared from powders of perovskite oxide-type CaTiO3 without cracking by phase inversion method. Polyetherimide was used as a polymeric binder in the method. The resulting green membranes, composed of CaTiO3 powder and polyetherimide binder, were sintered at 890, 1100 or 1200 °C. The crystal phase of CaTiO3 was analyzed using X-Ray Diffraction (XRD. The XRD pattern of the synthesized CaTiO3 powder was matched with the reference indicating the formation of CaTiO3 structure. Sintering at 890 °C fails to form a strong membrane. Scanning Electron Microscope (SEM images of the membranes showed that the membrane had the asymmetric structure with dense layer on one side and porous layer on the other side. The pores in the porous layer were both finger-like and sponge-like structure. The mechanical strength of the membranes, which were determined by Vickers micro hardness method, varied from 3.5 to 25.8 Hv. The strongest membrane without any crack was resulted from sintering at 1200°C with hardness values between 19.4 and 25.8 Hv. Thermal expansion coefficients of the asymmetric membranes sintered at 1100 and 1200 °C, measured with Thermomechanical Analyzer (TMA, were 10.82 × 10-6 and 12.78 × 10-6.C-1 respectively.

  8. Superconducting Cd and Ca doped 123 phase in Cdo.8Ba2(Y0.7Ca0.4) Cu3.5Oy

    International Nuclear Information System (INIS)

    Balchev, N.; Kovachev, V; THOMAS, J.; BIEGER, W.; Konstantinov, K.; Kunev, B.

    1999-01-01

    A new Cd-containing superconductor with nominal composition of Cd 0.8 Ba 2 (Y 0.7 Ca 0.4 ) Cu 3.5 O y and T c = 80 K was synthesized and investigated. The obtained XRD pattern shows that the dominating phase is an orthorhombic 123. It was shown that the presence of Cd and Ca facilitates the 123 phase formation. The results of the EDX analysis on SEM and TEM have shown that the distribution of the Cd and Ca in the samples is inhomogeneous. The two elements enter the 123 phase in most of the investigated crystals and form a new Cd-Ba-Y-Ca-Cu-O superconducting compound

  9. Quantifying Ca2+ release and inactivation of Ca2+ release in fast- and slow-twitch muscles.

    Science.gov (United States)

    Barclay, C J

    2012-12-01

    The aims of this study were to quantify the Ca(2+) release underlying twitch contractions of mammalian fast- and slow-twitch muscle and to comprehensively describe the transient inactivation of Ca(2+) release following a stimulus. Experiments were performed using bundles of fibres from mouse extensor digitorum longus (EDL) and soleus muscles. Ca(2+) release was quantified from the amount of ATP used to remove Ca(2+) from the myoplasm following stimulation. ATP turnover by crossbridges was blocked pharmacologically (N-benzyl-p-toluenesulphonamide for EDL, blebbistatin for soleus) and muscle heat production was used as an index of Ca(2+) pump ATP turnover. At 20°C, Ca(2+) release in response to a single stimulus was 34 and 84 μmol (kg muscle)(-1) for soleus and EDL, respectively, and increased with temperature (30°C: soleus, 61 μmol kg(-1); EDL, 168 μmol kg(-1)). Delivery of another stimulus within 100 ms of the first produced a smaller Ca(2+) release. The maximum magnitude of the decrease in Ca(2+) release was greater in EDL than soleus. Ca(2+) release recovered with an exponential time course which was faster in EDL (mean time constant at 20°C, 32.1 ms) than soleus (65.6 ms) and faster at 30°C than at 20°C. The amounts of Ca(2+) released and crossbridge cycles performed are consistent with a scheme in which Ca(2+) binding to troponin-C allowed an average of ∼1.7 crossbridge cycles in the two muscles.

  10. Enhancement of Mechanical Properties of Extruded Mg-9Al-1Zn-1MM-0.7CaO-0.3Mn Alloy Through Pre-aging Treatment

    Science.gov (United States)

    Jeong, Seok Hoan; Kim, Yong Joo; Kong, Kyung Ho; Cho, Tae Hee; Kim, Young Kyun; Lim, Hyun Kyu; Kim, Won Tae; Kim, Do Hyang

    2018-03-01

    The effect of pre-aging treatment before extrusion has been investigated in Mg-9.0Al-1.0Zn-1MM-0.7CaO-0.3Mn alloy. The as-cast microstructure consists of α-Mg dendrite with secondary solidification phase particles, (Mg, Al)2Ca, β-Mg17Al12 and Al11RE3 at the inter-dendritic region. After extrusion, β-Mg17Al12 precipitates are present, but higher density and more homogeneous distribution in pre-aged alloy. In addition, μm-scale banded bulk β-Mg17Al12 particles are generated during extrusion. Al11RE3 particles are broken into small particles, and are aligned along the extrusion direction. (Mg, Al)2Ca particles are only slightly elongated along the extrusion direction, providing stronger particle stimulated nucleation (PSN) effect by severe deformation during extrusion. The mechanical properties can be significantly enhanced by introducing pre-aging treatment, i.e. β-Mg17Al12 precipitates provide grain refining and strengthening effects and (Mg, Al)2Ca particles provide PSN effect.

  11. Schaffer collateral inputs to CA1 excitatory and inhibitory neurons follow different connectivity rules.

    Science.gov (United States)

    Kwon, Osung; Feng, Linqing; Druckmann, Shaul; Kim, Jinhyun

    2018-05-04

    Neural circuits, governed by a complex interplay between excitatory and inhibitory neurons, are the substrate for information processing, and the organization of synaptic connectivity in neural network is an important determinant of circuit function. Here, we analyzed the fine structure of connectivity in hippocampal CA1 excitatory and inhibitory neurons innervated by Schaffer collaterals (SCs) using mGRASP in male mice. Our previous study revealed spatially structured synaptic connectivity between CA3-CA1 pyramidal cells (PCs). Surprisingly, parvalbumin-positive interneurons (PVs) showed a significantly more random pattern spatial structure. Notably, application of Peters' Rule for synapse prediction by random overlap between axons and dendrites enhanced structured connectivity in PCs, but, by contrast, made the connectivity pattern in PVs more random. In addition, PCs in a deep sublayer of striatum pyramidale appeared more highly structured than PCs in superficial layers, and little or no sublayer specificity was found in PVs. Our results show that CA1 excitatory PCs and inhibitory PVs innervated by the same SC inputs follow different connectivity rules. The different organizations of fine scale structured connectivity in hippocampal excitatory and inhibitory neurons provide important insights into the development and functions of neural networks. SIGNIFICANCE STATEMENT Understanding how neural circuits generate behavior is one of the central goals of neuroscience. An important component of this endeavor is the mapping of fine-scale connection patterns that underlie, and help us infer, signal processing in the brain. Here, using our recently developed synapse detection technology (mGRASP and neuTube), we provide detailed profiles of synaptic connectivity in excitatory (CA1 pyramidal) and inhibitory (CA1 parvalbumin-positive) neurons innervated by the same presynaptic inputs (CA3 Schaffer collaterals). Our results reveal that these two types of CA1 neurons follow

  12. Chronic Loss of CA2 Transmission Leads to Hippocampal Hyperexcitability.

    Science.gov (United States)

    Boehringer, Roman; Polygalov, Denis; Huang, Arthur J Y; Middleton, Steven J; Robert, Vincent; Wintzer, Marie E; Piskorowski, Rebecca A; Chevaleyre, Vivien; McHugh, Thomas J

    2017-05-03

    Hippocampal CA2 pyramidal cells project into both the neighboring CA1 and CA3 subfields, leaving them well positioned to influence network physiology and information processing for memory and space. While recent work has suggested unique roles for CA2, including encoding position during immobility and generating ripple oscillations, an interventional examination of the integrative functions of these connections has yet to be reported. Here we demonstrate that CA2 recruits feedforward inhibition in CA3 and that chronic genetically engineered shutdown of CA2-pyramidal-cell synaptic transmission consequently results in increased excitability of the recurrent CA3 network. In behaving mice, this led to spatially triggered episodes of network-wide hyperexcitability during exploration accompanied by the emergence of high-frequency discharges during rest. These findings reveal CA2 as a regulator of network processing in hippocampus and suggest that CA2-mediated inhibition in CA3 plays a key role in establishing the dynamic excitatory and inhibitory balance required for proper network function. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Synthesis and photoluminescence of Ca-(Sn,Ti)-Si-O compounds

    International Nuclear Information System (INIS)

    Abe, Shunsuke; Yamane, Hisanori; Yoshida, Hisashi

    2010-01-01

    The phase relation of the compounds prepared in the CaO-SnO 2 -SiO 2 system at 1673 K and in the CaO-TiO 2 -SiO 2 system at 1573 K was investigated in order to explore new Ti 4+ -activated stannate phosphors. Solid solutions of Ca(Sn 1-x Ti x )SiO 5 and Ca 3 (Sn 1-y Ti y )Si 2 O 9 were synthesized at x = 0-1.0 and y = 0-0.10, respectively, and their crystal structures were analyzed by powder X-ray diffraction. Photoluminescence of these solid solutions was observed in a broad range of a visible light wavelength region under ultraviolet (UV) light excitation. The peaks of the emission band of Ca(Sn 0.97 Ti 0.03 )SiO 5 and Ca 3 (Sn 0.925 Ti 0.075 )Si 2 O 9 were at 510 nm under excitation of 252 nm and at 534 nm under excitation of 258 nm, respectively. The absorption edges estimated by the diffuse reflectance spectra were at 300 nm (4.1 eV) for CaSnSiO 5 and at 270 nm (4.6 eV) for Ca 3 SnSi 2 O 9 , suggesting that the excitation levels in Ca(Sn 1-x Ti x )SiO 5 were above the band gap of the host, although the levels in Ca 3 (Sn 1-y Ti y )Si 2 O 9 were within the band gap and near the conduction band edge.

  14. Solubility of calcium in CaO-CaCl2

    International Nuclear Information System (INIS)

    Perry, G.S.; Shaw, S.J.

    1991-06-01

    The Direct Oxide Reduction (DOR) process is well established as a process to produce plutonium metal from plutonium dioxide by reaction with calcium. Calcium chloride is added to dissolve the calcium oxide produced, allowing the metal to coalesce into a button. Since calcium metal melts at 840 0 C and DOR can take place successfully below this temperature, it is likely calcium dissolved in calcium chloride reacts with the plutonium dioxide. The solubility of calcium in calcium chloride is reasonably well established but the effect of the CaO formed during the DOR process on the solubility of calcium has not been previously determined. For this reason the solubility of calcium in CaCl 2 -CaO melts at 800 o C has been studied. The solubility decreases from 2.7 mol % in CaCl 2 to 0.4 mol % in 9 mol % CaO-CaCl 2 . (author)

  15. Dynamic immobilization of simulated radionuclide 133Cs in soil by thermal treatment/vitrification with nanometallic Ca/CaO composites

    International Nuclear Information System (INIS)

    Mallampati, Srinivasa Reddy; Mitoma, Yoshiharu; Okuda, Tetsuji; Simion, Cristian; Lee, Byeong Kyu

    2015-01-01

    Although direct radiation induced health impacts were considered benign, soil contamination with 137 Cs, due to its long-term radiological impact (30 years half-life) and its high biological availability is of a major concern in Japan in the aftermath of the Fukushima nuclear power plant disaster. Therefore 137 Cs reduction and immobilization in contaminated soil are recognized as important problems to be solved using suitable and effective technologies. One such thermal treatment/vitrification with nanometallic Ca/CaO amendments is a promising treatment for the ultimate immobilization of simulated radionuclide 133 Cs in soil, showing low leachability and zero evaporation. Immobilization efficiencies were 88%, 95% and 96% when the 133 Cs soil was treated at 1200 °C with activated carbon, fly ash and nanometallic Ca/CaO additives. In addition, the combination of nanometallic Ca/CaO and fly ash (1:1) enhanced the immobilization efficiency to 99%, while no evaporation of 133 Cs was observed. At lower temperatures (800 °C) the leachable fraction of Cs was only 6% (94% immobilization). Through the SEM–EDS analysis, decrease in the amount of Cs mass percent detectable on soil parti