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Sample records for calcium sensor ncs

  1. Fission yeast homolog of neuronal calcium sensor-1 (Ncs1p) regulates sporulation and confers calcium tolerance.

    PubMed

    Hamasaki-Katagiri, Nobuko; Molchanova, Tatiana; Takeda, Kazuyo; Ames, James B

    2004-03-26

    The neuronal calcium sensor (NCS) proteins (e.g. recoverin, neurocalcins, and frequenin) are expressed at highest levels in excitable cells, and some of them regulate desensitization of G protein-coupled receptors. Here we present NMR analysis and genetic functional studies of an NCS homolog in fission yeast (Ncs1p). Ncs1p binds three Ca2+ ions at saturation with an apparent affinity of 2 microm and Hill coefficient of 1.9. Analysis of NMR and fluorescence spectra of Ncs1p revealed significant Ca2+-induced protein conformational changes indicative of a Ca2+-myristoyl switch. The amino-terminal myristoyl group is sequestered inside a hydrophobic cavity of the Ca2+-free protein and becomes solvent-exposed in the Ca2+-bound protein. Subcellular fractionation experiments showed that myristoylation and Ca2+ binding by Ncs1p are essential for its translocation from cytoplasm to membranes. The ncs1 deletion mutant (ncs1Delta) showed two distinct phenotypes: nutrition-insensitive sexual development and a growth defect at high levels of extracellular Ca2+ (0.1 m CaCl(2)). Analysis of Ncs1p mutants lacking myristoylation (Ncs1p(G2A)) or deficient in Ca2+ binding (Ncs1p(E84Q/E120Q/E168Q)) revealed that Ca2+ binding was essential for both phenotypes, while myristoylation was less critical. Exogenous cAMP, a key regulator for sexual development, suppressed conjugation and sporulation of ncs1Delta, suggesting involvement of Ncs1p in the adenylate cyclase pathway turned on by the glucose-sensing G protein-coupled receptor Git3p. Starvation-independent sexual development of ncs1Delta was also complemented by retinal recoverin, which controls Ca2+-regulated desensitization of rhodopsin. In contrast, the Ca2+-intolerance of ncs1Delta was not affected by cAMP or recoverin, suggesting that the two ncs1Delta phenotypes are mechanistically independent. We propose that Schizosaccharomyces pombe Ncs1p negatively regulates sporulation perhaps by controlling Ca2+-dependent desensitization

  2. Datasets depicting mobility retardation of NCS proteins observed upon incubation with calcium, but not with magnesium, barium or strontium

    PubMed Central

    Viviano, Jeffrey; Krishnan, Anuradha; Scully, Jenna; Wu, Hao; Venkataraman, Venkat

    2016-01-01

    In this data article we show the specificity of the Ca2+-induced mobility shift in three proteins that belong to the neuronal calcium sensor (NCS) protein family: Hippocalcin, GCAP1 and GCAP2. These proteins did not display a shift in mobility in native gels when incubated with divalent cations other than Ca2+ – such as Mg2+, Ba2+, and Sr2+, even at 10× concentrations. The data is similar to that obtained with another NCS protein, neurocalcin delta (Viviano et al., 2016, “Electrophoretic Mobility Shift in Native Gels Indicates Calcium-dependent Structural Changes of Neuronal Calcium Sensor Proteins”, [1]). PMID:27222862

  3. Datasets depicting mobility retardation of NCS proteins observed upon incubation with calcium, but not with magnesium, barium or strontium.

    PubMed

    Viviano, Jeffrey; Krishnan, Anuradha; Scully, Jenna; Wu, Hao; Venkataraman, Venkat

    2016-06-01

    In this data article we show the specificity of the Ca(2+)-induced mobility shift in three proteins that belong to the neuronal calcium sensor (NCS) protein family: Hippocalcin, GCAP1 and GCAP2. These proteins did not display a shift in mobility in native gels when incubated with divalent cations other than Ca(2+) - such as Mg(2+), Ba(2+), and Sr(2+), even at 10× concentrations. The data is similar to that obtained with another NCS protein, neurocalcin delta (Viviano et al., 2016, "Electrophoretic Mobility Shift in Native Gels Indicates Calcium-dependent Structural Changes of Neuronal Calcium Sensor Proteins", [1]). PMID:27222862

  4. Paclitaxel accelerates spontaneous calcium oscillations in cardiomyocytes by interacting with NCS-1 and the InsP3R

    PubMed Central

    Zhang, Kun; Heidrich, Felix M.; DeGray, Brenda; Boehmerle, Wolfgang; Ehrlich, Barbara E.

    2010-01-01

    Paclitaxel (Taxol) is a microtubule-stabilizing compound that is used for cancer chemotherapy. However, Taxol administration is limited by serious side effects including cardiac arrhythmia, which cannot be explained by its microtubule-stabilizing effect. Recently, neuronal calcium sensor 1 (NCS-1), a calcium binding protein that modulates the inositol-1,4,5-trisphosphate receptor (InsP3R), was described as a binding partner of Taxol and as a substrate of calpain. We examined calcium signaling processes in cardiomyocytes after treatment with Taxol to investigate the basis of Taxol-induced cardiac arrhythmia. After treating isolated neonatal rat ventricular myocytes with a therapeutic concentration of Taxol for several hours live cell imaging experiments showed that the frequency of spontaneous calcium oscillations significantly increased. This effect was not mimicked by other tubulin-stabilizing agents. However, it was prevented by inhibiting the InsP3R. Taxol treated cells had increased expression of NCS-1, an effect also detectable after Taxol administration in vivo. Short hairpin RNA mediated knock down of NCS-1 decreased InsP3R dependent intracellular calcium release, whereas Taxol treatment, that increased NCS-1 levels, increased InsP3R dependent calcium release. The effects of Taxol were ryanodine receptor independent. At the single channel level Taxol and NCS-1 mediated an increase in InsP3R activity. Calpain activity was not affected by Taxol in cardiomyocytes suggesting a calpain independent signaling pathway. In short, our study shows that Taxol impacts calcium signaling and calcium oscillations in cardiomyocytes through NCS-1 and the InsP3R. PMID:20801127

  5. Neuronal Calcium Sensor 1 Has Two Variants with Distinct Calcium Binding Characteristics.

    PubMed

    Wang, Baisheng; Boeckel, Göran R; Huynh, Larry; Nguyen, Lien; Cao, Wenxiang; De La Cruz, Enrique M; Kaftan, Edward J; Ehrlich, Barbara E

    2016-01-01

    Neuronal calcium sensor-1 (NCS-1 Var1) is a calcium-binding protein expressed in most tissues. We examined a poorly characterized variant of NCS-1 (Var2), identified only in humans where the N-terminal 22 amino acid residues of native NCS-1(MGKSNSKLKPEVVEELTRKTY) were replaced with 4 different residues (MATI). Because alterations in the level of expression of NCS-1 Var1 and the expression of NCS-1 variants have been correlated with several neurological diseases, the relative expression and functional role of NCS-1 Var2 was examined. We found that NCS-1 Var2 mRNA levels are not found in mouse tissues and are expressed at levels ~1000-fold lower than NCS-1 Var1 in three different human cell lines (SHSY5Y, HEK293, MB231). Protein expression of both variants was only identified in cell lines overexpressing exogenous NCS-1 Var2. The calcium binding affinity is ~100 times weaker in purified NCS-1 Var2 than NCS-1 Var1. Because truncation of NCS-1 Var1 has been linked to functional changes in neurons, we determined whether the differing properties of the NCS-1 variants could potentially contribute to the altered cell function. In contrast to previous reports showing that overexpression of NCS-1 Var1 increases calcium-dependent processes, functional differences in cells overexpressing NCS-1 Var2 were undetectable in assays for cell growth, cell death and drug (paclitaxel) potency. Our results suggest that NCS-1 Var1 is the primary functional version of NCS-1. PMID:27575489

  6. Neuronal Calcium Sensor 1 Has Two Variants with Distinct Calcium Binding Characteristics

    PubMed Central

    Wang, Baisheng; Boeckel, Göran R.; Huynh, Larry; Nguyen, Lien; Cao, Wenxiang; De La Cruz, Enrique M.; Kaftan, Edward J.

    2016-01-01

    Neuronal calcium sensor-1 (NCS-1 Var1) is a calcium-binding protein expressed in most tissues. We examined a poorly characterized variant of NCS-1 (Var2), identified only in humans where the N-terminal 22 amino acid residues of native NCS-1(MGKSNSKLKPEVVEELTRKTY) were replaced with 4 different residues (MATI). Because alterations in the level of expression of NCS-1 Var1 and the expression of NCS-1 variants have been correlated with several neurological diseases, the relative expression and functional role of NCS-1 Var2 was examined. We found that NCS-1 Var2 mRNA levels are not found in mouse tissues and are expressed at levels ~1000-fold lower than NCS-1 Var1 in three different human cell lines (SHSY5Y, HEK293, MB231). Protein expression of both variants was only identified in cell lines overexpressing exogenous NCS-1 Var2. The calcium binding affinity is ~100 times weaker in purified NCS-1 Var2 than NCS-1 Var1. Because truncation of NCS-1 Var1 has been linked to functional changes in neurons, we determined whether the differing properties of the NCS-1 variants could potentially contribute to the altered cell function. In contrast to previous reports showing that overexpression of NCS-1 Var1 increases calcium-dependent processes, functional differences in cells overexpressing NCS-1 Var2 were undetectable in assays for cell growth, cell death and drug (paclitaxel) potency. Our results suggest that NCS-1 Var1 is the primary functional version of NCS-1. PMID:27575489

  7. Modulation of gamma oscillations in the pedunculopontine nucleus by neuronal calcium sensor protein-1: relevance to schizophrenia and bipolar disorder

    PubMed Central

    D'Onofrio, Stasia; Kezunovic, Nebojsa; Hyde, James R.; Luster, Brennon; Messias, Erick; Urbano, Francisco J.

    2014-01-01

    Reduced levels of gamma-band activity are present in schizophrenia and bipolar disorder patients. In the same disorders, increased neuronal calcium sensor protein-1 (NCS-1) expression was reported in a series of postmortem studies. These disorders are also characterized by sleep dysregulation, suggesting a role for the reticular activating system (RAS). The discovery of gamma-band activity in the pedunculopontine nucleus (PPN), the cholinergic arm of the RAS, revealed that such activity was mediated by high-threshold calcium channels that are regulated by NCS-1. We hypothesized that NCS-1 normally regulates gamma-band oscillations through these calcium channels and that excessive levels of NCS-1, such as would be expected with overexpression, decrease gamma-band activity. We found that PPN neurons in rat brain slices manifested gamma-band oscillations that were increased by low levels of NCS-1 but suppressed by high levels of NCS-1. Our results suggest that NCS-1 overexpression may be responsible for the decrease in gamma-band activity present in at least some schizophrenia and bipolar disorder patients. PMID:25376789

  8. The neuronal calcium sensor family of Ca2+-binding proteins.

    PubMed Central

    Burgoyne, R D; Weiss, J L

    2001-01-01

    Ca(2+) plays a central role in the function of neurons as the trigger for neurotransmitter release, and many aspects of neuronal activity, from rapid modulation to changes in gene expression, are controlled by Ca(2+). These actions of Ca(2+) must be mediated by Ca(2+)-binding proteins, including calmodulin, which is involved in Ca(2+) regulation, not only in neurons, but in most other cell types. A large number of other EF-hand-containing Ca(2+)-binding proteins are known. One family of these, the neuronal calcium sensor (NCS) proteins, has a restricted expression in retinal photoreceptors or neurons and neuroendocrine cells, suggesting that they have specialized roles in these cell types. Two members of the family (recoverin and guanylate cyclase-activating protein) have established roles in the regulation of phototransduction. Despite close sequence similarities, the NCS proteins have distinct neuronal distributions, suggesting that they have different functions. Recent work has begun to demonstrate the physiological roles of members of this protein family. These include roles in the modulation of neurotransmitter release, control of cyclic nucleotide metabolism, biosynthesis of polyphosphoinositides, regulation of gene expression and in the direct regulation of ion channels. In the present review we describe the known sequences and structures of the NCS proteins, information on their interactions with target proteins and current knowledge about their cellular and physiological functions. PMID:11115393

  9. Neuronal calcium sensor-1 deletion in the mouse decreases motivation and dopamine release in the nucleus accumbens.

    PubMed

    Ng, Enoch; Varaschin, Rafael K; Su, Ping; Browne, Caleb J; Hermainski, Joanna; Le Foll, Bernard; Pongs, Olaf; Liu, Fang; Trudeau, Louis-Eric; Roder, John C; Wong, Albert H C

    2016-03-15

    Calcium sensors detect intracellular calcium changes and interact with downstream targets to regulate many functions. Neuronal Calcium Sensor-1 (NCS-1) or Frequenin is widely expressed in the nervous system, and involved in neurotransmission, synaptic plasticity and learning. NCS-1 interacts with and regulates dopamine D2 receptor (D2R) internalization and is implicated in disorders like schizophrenia and substance abuse. However, the role of NCS-1 in behaviors dependent on dopamine signaling in the striatum, where D2R is most highly expressed, is unknown. We show that Ncs-1 deletion in the mouse decreases willingness to work for food. Moreover, Ncs-1 knockout mice have significantly lower activity-dependent dopamine release in the nucleus accumbens core in acute slice recordings. In contrast, food preference, responding for conditioned reinforcement, ability to represent changes in reward value, and locomotor response to amphetamine are not impaired. These studies identify novel roles for NCS-1 in regulating activity-dependent striatal dopamine release and aspects of motivated behavior. PMID:26738968

  10. Chronic exposure to paclitaxel diminishes phosphoinositide signaling by calpain-mediated neuronal calcium sensor-1 degradation.

    PubMed

    Boehmerle, Wolfgang; Zhang, Kun; Sivula, Michael; Heidrich, Felix M; Lee, Yashang; Jordt, Sven-Eric; Ehrlich, Barbara E

    2007-06-26

    Paclitaxel (Taxol) is a well established chemotherapeutic agent for the treatment of solid tumors, but it is limited in its usefulness by the frequent induction of peripheral neuropathy. We found that prolonged exposure of a neuroblastoma cell line and primary rat dorsal root ganglia with therapeutic concentrations of Taxol leads to a reduction in inositol trisphosphate (InsP(3))-mediated Ca(2+) signaling. We also observed a Taxol-specific reduction in neuronal calcium sensor 1 (NCS-1) protein levels, a known modulator of InsP(3) receptor (InsP(3)R) activity. This reduction was also found in peripheral neuronal tissue from Taxol treated animals. We further observed that short hairpin RNA-mediated NCS-1 knockdown had a similar effect on phosphoinositide-mediated Ca(2+) signaling. When NCS-1 protein levels recovered, so did InsP(3)-mediated Ca(2+) signaling. Inhibition of the Ca(2+)-activated protease mu-calpain prevented alterations in phosphoinositide-mediated Ca(2+) signaling and NCS-1 protein levels. We also found that NCS-1 is readily degraded by mu-calpain in vitro and that mu-calpain activity is increased in Taxol but not vehicle-treated cells. From these results, we conclude that prolonged exposure to Taxol activates mu-calpain, which leads to the degradation of NCS-1, which, in turn, attenuates InsP(3)mediated Ca(2+) signaling. These findings provide a previously undescribed approach to understanding and treating Taxol-induced peripheral neuropathy. PMID:17581879

  11. Characterisation of the Interaction of the C-Terminus of the Dopamine D2 Receptor with Neuronal Calcium Sensor-1

    PubMed Central

    Lian, Lu-Yun; Pandalaneni, Sravan R.; Patel, Pryank; McCue, Hannah V.; Haynes, Lee P.; Burgoyne, Robert D.

    2011-01-01

    NCS-1 is a member of the neuronal calcium sensor (NCS) family of EF-hand Ca2+ binding proteins which has been implicated in several physiological functions including regulation of neurotransmitter release, membrane traffic, voltage gated Ca2+ channels, neuronal development, synaptic plasticity, and learning. NCS-1 binds to the dopamine D2 receptor, potentially affecting its internalisation and controlling dopamine D2 receptor surface expression. The D2 receptor binds NCS-1via a short 16-residue cytoplasmic C-terminal tail. We have used NMR and fluorescence spectroscopy to characterise the interactions between the NCS-1/Ca2+ and D2 peptide. The data show that NCS-1 binds D2 peptide with a Kd of ∼14.3 µM and stoichiometry of peptide binding to NCS-1 of 2∶1. NMR chemical shift mapping confirms that D2 peptide binds to the large, solvent-exposed hydrophobic groove, on one face of the NCS-1 molecule, with residues affected by the presence of the peptide spanning both the N and C-terminal portions of the protein. The NMR and mutagenesis data further show that movement of the C-terminal helix 11 of NCS-1 to fully expose the hydrophobic groove is important for D2 peptide binding. Molecular docking using restraints derived from the NMR chemical shift data, together with the experimentally-derived stoichiometry, produced a model of the complex between NCS-1 and the dopamine receptor, in which two molecules of the receptor are able to simultaneously bind to the NCS-1 monomer. PMID:22114693

  12. Interaction of ARF-1.1 and neuronal calcium sensor-1 in the control of the temperature-dependency of locomotion in Caenorhabditis elegans

    PubMed Central

    Todd, Paul A. C.; McCue, Hannah V.; Haynes, Lee P.; Barclay, Jeff W.; Burgoyne, Robert D.

    2016-01-01

    Neuronal calcium sensor-1 (NCS-1) mediates changes in cellular function by regulating various target proteins. Many potential targets have been identified but the physiological significance of only a few has been established. Upon temperature elevation, Caenorhabditis elegans exhibits reversible paralysis. In the absence of NCS-1, worms show delayed onset and a shorter duration of paralysis. This phenotype can be rescued by re-expression of ncs-1 in AIY neurons. Mutants with defects in four potential NCS-1 targets (arf-1.1, pifk-1, trp-1 and trp-2) showed qualitatively similar phenotypes to ncs-1 null worms, although the effect of pifk-1 mutation on time to paralysis was considerably delayed. Inhibition of pifk-1 also resulted in a locomotion phenotype. Analysis of double mutants showed no additive effects between mutations in ncs-1 and trp-1 or trp-2. In contrast, double mutants of arf-1.1 and ncs-1 had an intermediate phenotype, consistent with NCS-1 and ARF-1.1 acting in the same pathway. Over-expression of arf-1.1 in the AIY neurons was sufficient to rescue partially the phenotype of both the arf-1.1 and the ncs-1 null worms. These findings suggest that ARF-1.1 interacts with NCS-1 in AIY neurons and potentially pifk-1 in the Ca2+ signaling pathway that leads to inhibited locomotion at an elevated temperature. PMID:27435667

  13. Interaction of ARF-1.1 and neuronal calcium sensor-1 in the control of the temperature-dependency of locomotion in Caenorhabditis elegans.

    PubMed

    Todd, Paul A C; McCue, Hannah V; Haynes, Lee P; Barclay, Jeff W; Burgoyne, Robert D

    2016-01-01

    Neuronal calcium sensor-1 (NCS-1) mediates changes in cellular function by regulating various target proteins. Many potential targets have been identified but the physiological significance of only a few has been established. Upon temperature elevation, Caenorhabditis elegans exhibits reversible paralysis. In the absence of NCS-1, worms show delayed onset and a shorter duration of paralysis. This phenotype can be rescued by re-expression of ncs-1 in AIY neurons. Mutants with defects in four potential NCS-1 targets (arf-1.1, pifk-1, trp-1 and trp-2) showed qualitatively similar phenotypes to ncs-1 null worms, although the effect of pifk-1 mutation on time to paralysis was considerably delayed. Inhibition of pifk-1 also resulted in a locomotion phenotype. Analysis of double mutants showed no additive effects between mutations in ncs-1 and trp-1 or trp-2. In contrast, double mutants of arf-1.1 and ncs-1 had an intermediate phenotype, consistent with NCS-1 and ARF-1.1 acting in the same pathway. Over-expression of arf-1.1 in the AIY neurons was sufficient to rescue partially the phenotype of both the arf-1.1 and the ncs-1 null worms. These findings suggest that ARF-1.1 interacts with NCS-1 in AIY neurons and potentially pifk-1 in the Ca(2+) signaling pathway that leads to inhibited locomotion at an elevated temperature. PMID:27435667

  14. Modulation of CaV2.1 channels by neuronal calcium sensor-1 induces short-term synaptic facilitation.

    PubMed

    Yan, Jin; Leal, Karina; Magupalli, Venkat G; Nanou, Evanthia; Martinez, Gilbert Q; Scheuer, Todd; Catterall, William A

    2014-11-01

    Facilitation and inactivation of P/Q-type Ca2+ currents mediated by Ca2+/calmodulin binding to Ca(V)2.1 channels contribute to facilitation and rapid depression of synaptic transmission, respectively. Other calcium sensor proteins displace calmodulin from its binding site and differentially modulate P/Q-type Ca2 + currents, resulting in diverse patterns of short-term synaptic plasticity. Neuronal calcium sensor-1 (NCS-1, frequenin) has been shown to enhance synaptic facilitation, but the underlying mechanism is unclear. We report here that NCS-1 directly interacts with IQ-like motif and calmodulin-binding domain in the C-terminal domain of Ca(V)2.1 channel. NCS-1 reduces Ca2 +-dependent inactivation of P/Q-type Ca2+ current through interaction with the IQ-like motif and calmodulin-binding domain without affecting peak current or activation kinetics. Expression of NCS-1 in presynaptic superior cervical ganglion neurons has no effect on synaptic transmission, eliminating effects of this calcium sensor protein on endogenous N-type Ca2+ currents and the endogenous neurotransmitter release machinery. However, in superior cervical ganglion neurons expressing wild-type Ca(V)2.1 channels, co-expression of NCS-1 induces facilitation of synaptic transmission in response to paired pulses and trains of depolarizing stimuli, and this effect is lost in Ca(V)2.1 channels with mutations in the IQ-like motif and calmodulin-binding domain. These results reveal that NCS-1 directly modulates Ca(V)2.1 channels to induce short-term synaptic facilitation and further demonstrate that CaS proteins are crucial in fine-tuning short-term synaptic plasticity. PMID:25447945

  15. Single-Molecule Folding Mechanisms of the apo- and Mg2+-Bound States of Human Neuronal Calcium Sensor-1

    PubMed Central

    Naqvi, Mohsin M.; Heidarsson, Pétur O.; Otazo, Mariela R.; Mossa, Alessandro; Kragelund, Birthe B.; Cecconi, Ciro

    2015-01-01

    Neuronal calcium sensor-1 (NCS-1) is the primordial member of a family of proteins responsible primarily for sensing changes in neuronal Ca2+ concentration. NCS-1 is a multispecific protein interacting with a number of binding partners in both calcium-dependent and independent manners, and acting in a variety of cellular processes in which it has been linked to a number of disorders such as schizophrenia and autism. Despite extensive studies on the Ca2+-activated state of NCS proteins, little is known about the conformational dynamics of the Mg2+-bound and apo states, both of which are populated, at least transiently, at resting Ca2+ conditions. Here, we used optical tweezers to study the folding behavior of individual NCS-1 molecules in the presence of Mg2+ and in the absence of divalent ions. Under tension, the Mg2+-bound state of NCS-1 unfolds and refolds in a three-state process by populating one intermediate state consisting of a folded C-domain and an unfolded N-domain. The interconversion at equilibrium between the different molecular states populated by NCS-1 was monitored in real time through constant-force measurements and the energy landscapes underlying the observed transitions were reconstructed through hidden Markov model analysis. Unlike what has been observed with the Ca2+-bound state, the presence of Mg2+ allows both the N- and C-domain to fold through all-or-none transitions with similar refolding rates. In the absence of divalent ions, NCS-1 unfolds and refolds reversibly in a two-state reaction involving only the C-domain, whereas the N-domain has no detectable transitions. Overall, the results allowed us to trace the progression of NCS-1 folding along its energy landscapes and provided a solid platform for understanding the conformational dynamics of similar EF-hand proteins. PMID:26153708

  16. Temperature-Dependent Conformational Properties of Human Neuronal Calcium Sensor-1 Protein Revealed by All-Atom Simulations.

    PubMed

    Zhu, Yuzhen; Ma, Buyong; Qi, Ruxi; Nussinov, Ruth; Zhang, Qingwen

    2016-04-14

    Neuronal calcium sensor-1 (NCS-1) protein has orthologues from Saccharomyces cerevisiae to human with highly conserved amino acid sequences. NCS-1 is an important factor controlling the animal's response to temperature change. This leads us to investigate the temperature effects on the conformational dynamics of human NCS-1 at 310 and 316 K by all-atom molecular dynamics (MD) simulations and dynamic community network analysis. Four independent 500 ns MD simulations show that secondary structure content at 316 K is similar to that at 310 K, whereas the global protein structure is expanded. Loop 3 (L3) adopts an extended state occuping the hydrophobic crevice, and the number of suboptimal communication paths between residue D176 and V190 is reduced at 316 K. The dynamic community network analysis suggests that the interdomain correlation is weakened, and the intradomain coupling is strengthened at 316 K. The elevated temperature reduces the number of the salt bridges, especially in C-domain. This study suggests that the elevated temperature affects the conformational dynamics of human NCS-1 protein. Comparison of the structural dynamics of R102Q mutant and Δ176-190 truncated NCS-1 suggests that the structural and dynamical response of NCS-1 protein to elevated temperature may be one of its intrinsic functional properties. PMID:27007011

  17. Neuronal calcium sensor proteins are direct targets of the insulinotropic agent repaglinide.

    PubMed Central

    Okada, Miki; Takezawa, Daisuke; Tachibanaki, Shuji; Kawamura, Satoru; Tokumitsu, Hiroshi; Kobayashi, Ryoji

    2003-01-01

    The NCS (neuronal calcium sensor) proteins, including neurocalcins, recoverins and visinin-like proteins are members of a family of Ca2+-sensitive regulators, each with three Ca2+-binding EF-hand motifs. In plants, lily CCaMK [chimaeric Ca2+/CaM (calmodulin)-dependent protein kinase] and its PpCaMK ( Physcomitrella patens CCaMK) homologue are characterized by a visinin-like domain with three EF-hands. In the present study, in an effort to discover NCS antagonists, we screened a total of 43 compounds using Ca2+-dependent drug affinity chromatography and found that the insulinotropic agent repaglinide targets the NCS protein family. Repaglinide was found to bind to NCS proteins, but not to CaM or S100 proteins, in a Ca2+-dependent manner. Furthermore, the drug antagonized the inhibitory action of recoverin in a rhodopsin kinase assay with IC50 values of 400 microM. Moreover, repaglinide tightly bound to the visinin-like domain of CCaMK and PpCaMK in a Ca2+-dependent manner and antagonized the regulatory function of the domain with IC50 values of 55 and 4 microM for CCaMK and PpCaMK respectively. Although both repaglinide and a potent insulin secretagogue, namely glibenclamide, blocked K(ATP) channels with similar potency, glibenclamide had no antagonizing effect on the Ca2+-stimulated CCaMK and PpCaMK autophosphorylation, mediated by their visinin-like domain. In addition, a typical CaM antagonist, trifluoperazine, had no effect on the CCaMK and PpCaMK autophosphorylation. Repaglinide appears to be the first antagonist of NCS proteins and visinin-like domain-bearing enzymes. It may serve as a useful tool for evaluating the physiological functions of the NCS protein family. In addition, since repaglinide selectively targets NCS proteins among the EF-hand Ca2+-binding proteins, it is a potential lead compound for the development of more potent NCS antagonists. PMID:12844348

  18. Neuronal Calcium Sensor-1 Binds the D2 Dopamine Receptor and G-protein-coupled Receptor Kinase 1 (GRK1) Peptides Using Different Modes of Interactions*

    PubMed Central

    Pandalaneni, Sravan; Karuppiah, Vijaykumar; Saleem, Muhammad; Haynes, Lee P.; Burgoyne, Robert D.; Mayans, Olga; Derrick, Jeremy P.; Lian, Lu-Yun

    2015-01-01

    Neuronal calcium sensor-1 (NCS-1) is the primordial member of the neuronal calcium sensor family of EF-hand Ca2+-binding proteins. It interacts with both the G-protein-coupled receptor (GPCR) dopamine D2 receptor (D2R), regulating its internalization and surface expression, and the cognate kinases GRK1 and GRK2. Determination of the crystal structures of Ca2+/NCS-1 alone and in complex with peptides derived from D2R and GRK1 reveals that the differential recognition is facilitated by the conformational flexibility of the C-lobe-binding site. We find that two copies of the D2R peptide bind within the hydrophobic crevice on Ca2+/NCS-1, but only one copy of the GRK1 peptide binds. The different binding modes are made possible by the C-lobe-binding site of NCS-1, which adopts alternative conformations in each complex. C-terminal residues Ser-178–Val-190 act in concert with the flexible EF3/EF4 loop region to effectively form different peptide-binding sites. In the Ca2+/NCS-1·D2R peptide complex, the C-terminal region adopts a 310 helix-turn-310 helix, whereas in the GRK1 peptide complex it forms an α-helix. Removal of Ser-178–Val-190 generated a C-terminal truncation mutant that formed a dimer, indicating that the NCS-1 C-terminal region prevents NCS-1 oligomerization. We propose that the flexible nature of the C-terminal region is essential to allow it to modulate its protein-binding sites and adapt its conformation to accommodate both ligands. This appears to be driven by the variability of the conformation of the C-lobe-binding site, which has ramifications for the target specificity and diversity of NCS-1. PMID:25979333

  19. Fast Kinetics of Calcium Signaling and Sensor Design

    PubMed Central

    Tang, Shen; Reddish, Florence; Zhuo, You; Yang, Jenny J.

    2015-01-01

    Fast calcium signaling is regulated by numerous calcium channels exhibiting high spatiotemporal profiles which are currently measured by fluorescent calcium sensors. There is still a strong need to improve the kinetics of genetically encoded calcium indicators (sensors) to capture calcium dynamics in the millisecond time frame. In this review, we summarize several major fast calcium signaling pathways and discuss the recent developments and application of genetically encoded calcium indicators to detect these pathways. A new class of genetically encoded calcium indicators designed with site-directed mutagenesis on the surface of beta-barrel fluorescent proteins to form a pentagonal bipyramidal-like calcium binding domain dramatically accelerates calcium binding kinetics. Furthermore, novel genetically encoded calcium indicators with significantly increased fluorescent lifetime change are advantageous in deep-field imaging with high light-scattering and notable morphology change. PMID:26151819

  20. EVALUATION OF CALCIUM SENSORS IN FRESH AND SALTWATER

    EPA Science Inventory

    The Orion Calcium Ion Electrode No. 93-20 was evaluated for suitability as a calcium ion sensor for monitoring or in-situ marine applications by testing for the following parameters: accuracy, precision, temperature dependence, short- and long-term stability, durability, sensitiv...

  1. NATIONAL COMORBIDITY SURVEY (NCS)

    EPA Science Inventory

    The National Comorbidity Survey (NCS) was a collaborative epidemiologic investigation designed to study the prevalence and correlates of DSM III-R disorders and patterns and correlates of service utilization for these disorders. The NCS was the first survey to administer a struct...

  2. Direct single-molecule observation of calcium-dependent misfolding in human neuronal calcium sensor-1.

    PubMed

    Heidarsson, Pétur O; Naqvi, Mohsin M; Otazo, Mariela R; Mossa, Alessandro; Kragelund, Birthe B; Cecconi, Ciro

    2014-09-01

    Neurodegenerative disorders are strongly linked to protein misfolding, and crucial to their explication is a detailed understanding of the underlying structural rearrangements and pathways that govern the formation of misfolded states. Here we use single-molecule optical tweezers to monitor misfolding reactions of the human neuronal calcium sensor-1, a multispecific EF-hand protein involved in neurotransmitter release and linked to severe neurological diseases. We directly observed two misfolding trajectories leading to distinct kinetically trapped misfolded conformations. Both trajectories originate from an on-pathway intermediate state and compete with native folding in a calcium-dependent manner. The relative probability of the different trajectories could be affected by modulating the relaxation rate of applied force, demonstrating an unprecedented real-time control over the free-energy landscape of a protein. Constant-force experiments in combination with hidden Markov analysis revealed the free-energy landscape of the misfolding transitions under both physiological and pathological calcium concentrations. Remarkably for a calcium sensor, we found that higher calcium concentrations increased the lifetimes of the misfolded conformations, slowing productive folding to the native state. We propose a rugged, multidimensional energy landscape for neuronal calcium sensor-1 and speculate on a direct link between protein misfolding and calcium dysregulation that could play a role in neurodegeneration. PMID:25157171

  3. Direct single-molecule observation of calcium-dependent misfolding in human neuronal calcium sensor-1

    PubMed Central

    Heidarsson, Pétur O.; Naqvi, Mohsin M.; Otazo, Mariela R.; Mossa, Alessandro; Kragelund, Birthe B.; Cecconi, Ciro

    2014-01-01

    Neurodegenerative disorders are strongly linked to protein misfolding, and crucial to their explication is a detailed understanding of the underlying structural rearrangements and pathways that govern the formation of misfolded states. Here we use single-molecule optical tweezers to monitor misfolding reactions of the human neuronal calcium sensor-1, a multispecific EF-hand protein involved in neurotransmitter release and linked to severe neurological diseases. We directly observed two misfolding trajectories leading to distinct kinetically trapped misfolded conformations. Both trajectories originate from an on-pathway intermediate state and compete with native folding in a calcium-dependent manner. The relative probability of the different trajectories could be affected by modulating the relaxation rate of applied force, demonstrating an unprecedented real-time control over the free-energy landscape of a protein. Constant-force experiments in combination with hidden Markov analysis revealed the free-energy landscape of the misfolding transitions under both physiological and pathological calcium concentrations. Remarkably for a calcium sensor, we found that higher calcium concentrations increased the lifetimes of the misfolded conformations, slowing productive folding to the native state. We propose a rugged, multidimensional energy landscape for neuronal calcium sensor-1 and speculate on a direct link between protein misfolding and calcium dysregulation that could play a role in neurodegeneration. PMID:25157171

  4. The calcium sensor synaptotagmin 7 is required for synaptic facilitation.

    PubMed

    Jackman, Skyler L; Turecek, Josef; Belinsky, Justine E; Regehr, Wade G

    2016-01-01

    It has been known for more than 70 years that synaptic strength is dynamically regulated in a use-dependent manner. At synapses with a low initial release probability, closely spaced presynaptic action potentials can result in facilitation, a short-term form of enhancement in which each subsequent action potential evokes greater neurotransmitter release. Facilitation can enhance neurotransmitter release considerably and can profoundly influence information transfer across synapses, but the underlying mechanism remains a mystery. One proposed mechanism is that a specialized calcium sensor for facilitation transiently increases the probability of release, and this sensor is distinct from the fast sensors that mediate rapid neurotransmitter release. Yet such a sensor has never been identified, and its very existence has been disputed. Here we show that synaptotagmin 7 (Syt7) is a calcium sensor that is required for facilitation at several central synapses. In Syt7-knockout mice, facilitation is eliminated even though the initial probability of release and the presynaptic residual calcium signals are unaltered. Expression of wild-type Syt7 in presynaptic neurons restored facilitation, whereas expression of a mutated Syt7 with a calcium-insensitive C2A domain did not. By revealing the role of Syt7 in synaptic facilitation, these results resolve a longstanding debate about a widespread form of short-term plasticity, and will enable future studies that may lead to a deeper understanding of the functional importance of facilitation. PMID:26738595

  5. Network Characterization Service (NCS)

    SciTech Connect

    Jin, Guojun; Yang, George; Crowley, Brian; Agarwal, Deborah

    2001-06-06

    Distributed applications require information to effectively utilize the network. Some of the information they require is the current and maximum bandwidth, current and minimum latency, bottlenecks, burst frequency, and congestion extent. This type of information allows applications to determine parameters like optimal TCP buffer size. In this paper, we present a cooperative information-gathering tool called the network characterization service (NCS). NCS runs in user space and is used to acquire network information. Its protocol is designed for scalable and distributed deployment, similar to DNS. Its algorithms provide efficient, speedy and accurate detection of bottlenecks, especially dynamic bottlenecks. On current and future networks, dynamic bottlenecks do and will affect network performance dramatically.

  6. The calcium sensor synaptotagmin 7 is required for synaptic facilitation

    PubMed Central

    Jackman, Skyler L.; Turecek, Josef; Belinsky, Justine E.

    2015-01-01

    It has been known for over 70 years that synaptic strength is dynamically regulated in a use-dependent manner1. At synapses with a low initial release probability, closely spaced presynaptic action potentials can result in facilitation, a short-term form of enhancement where each subsequent action potential evokes greater neurotransmitter release2. Facilitation can enhance neurotransmitter release manyfold and profoundly influence information transfer across synapses3, but the underlying mechanism remains a mystery. Among the proposed mechanisms is that a specialized calcium sensor for facilitation transiently increases the probability of release2,4 and is distinct from the fast sensors that mediate rapid neurotransmitter release. Yet such a sensor has never been identified, and its very existence has been disputed5,6. Here we show that synaptotagmin 7 (syt7) is a calcium sensor that is required for facilitation at multiple central synapses. In syt7 knockout mice, facilitation is eliminated even though the initial probability of release and presynaptic residual calcium signals are unaltered. Expression of wild-type syt7 in presynaptic neurons restored facilitation, whereas expression of a mutated syt7 with a calcium-insensitive C2A domain did not. By revealing the role of syt7 in synaptic facilitation, these results resolve a longstanding debate about a widespread form of short-term plasticity, and will enable future studies that may lead to a deeper understanding of the functional importance of facilitation. PMID:26738595

  7. Assembly and Calcium Binding Properties of Quantum Dot-Calmodulin Calcium Sensor.

    PubMed

    Eun, Su-yong; Nguyen-ta, Kim; Yoo, Hoon; Silva, Gabriel A; Kim, Soon-jong

    2016-02-01

    We have developed the first nanoengineered quantum dot molecular complex designed to measure changes of calcium ion (Ca2+) concentration at high spatial and temporal resolutions in real time. The sensor is ratiometric and composed of three components: a quantum dot (QD) emitting at 620 nm as a fluorescence donor, an organic dye (Alexa Fluor 647) as a fluorescence acceptor, and a calmodulin-M13 (CaM-M13) protein part as a calcium sensing component. In this work, we have determined the maximal number of CaM-M13 required for saturating a single QD particle to be approximately 16. The dissociation constant, Kd of the QD-based calcium ion sensor was also estimated to be around 30 microM. PMID:27433729

  8. Demonstration of Binding of Neuronal Calcium Sensor-1 to the Cav2.1 P/Q-Type Calcium Channel

    PubMed Central

    2014-01-01

    In neurons, entry of extracellular calcium (Ca2+) into synaptic terminals through Cav2.1 (P/Q-type) Ca2+ channels is the driving force for exocytosis of neurotransmitter-containing synaptic vesicles. This class of Ca2+ channel is, therefore, pivotal during normal neurotransmission in higher organisms. In response to channel opening and Ca2+ influx, specific Ca2+-binding proteins associate with cytoplasmic regulatory domains of the P/Q channel to modulate subsequent channel opening. Channel modulation in this way influences synaptic plasticity with consequences for higher-level processes such as learning and memory acquisition. The ubiquitous Ca2+-sensing protein calmodulin (CaM) regulates the activity of all types of mammalian voltage-gated Ca2+ channels, including the P/Q class, by direct binding to specific regulatory motifs. More recently, experimental evidence has highlighted a role for additional Ca2+-binding proteins, particularly of the CaBP and NCS families in the regulation of P/Q channels. NCS-1 is a protein found from yeast to humans and that regulates a diverse number of cellular functions. Physiological and genetic evidence indicates that NCS-1 regulates P/Q channel activity, including calcium-dependent facilitation, although a direct physical association between the proteins has yet to be demonstrated. In this study, we aimed to determine if there is a direct interaction between NCS-1 and the C-terminal cytoplasmic tail of the Cav2.1 α-subunit. Using distinct but complementary approaches, including in vitro binding of bacterially expressed recombinant proteins, fluorescence spectrophotometry, isothermal titration calorimetry, nuclear magnetic resonance, and expression of fluorescently tagged proteins in mammalian cells, we show direct binding and demonstrate that CaM can compete for it. We speculate about how NCS-1/Cav2.1 association might add to the complexity of calcium channel regulation mediated by other known calcium-sensing proteins and how

  9. Neuronal calcium sensor-1 and cocaine addiction: A genetic association study in African-Americans and European Americans

    PubMed Central

    Multani, Pushpinder K.; Clarke, Toni-Kim; Narasimhan, Sneha; Ambrose-Lanci, Lisa; Kampman, Kyle M.; Pettinati, Helen M.; Oslin, David W.; O’Brien, Charles P.; Berrettini, Wade H.; Lohoff, Falk W.

    2013-01-01

    Genes involved in drug reward pathways are plausible candidates for susceptibility to substance use disorders. Given the prominent role of dopamine in drug reward, dopamine receptor-interacting proteins (DRIPs) such as the neuronal calcium sensor-1 (NCS-1) protein have been hypothesized to play a role in the pathophysiology of cocaine addiction (CA). In this study, we investigated whether genetic variants in the NCS-1 gene confer risk to CA. We genotyped 8 SNPs (rs4837479, rs7849345, rs3824544, rs10819611, rs947513, rs2277200, rs7873936 and rs1342043) in our discovery sample (cases n = 796, controls n = 416) of African descent. Confirmation of associated or trending SNPs (rs7849345, rs10819611, rs1342043) was attempted using a replication sample of African American (AA) ethnicity (cases n = 335, controls n = 336) and European-American (EA) ancestry (cases n = 336, controls n = 656). Secondary sex specific analysis was also carried out for each SNP in both AA and EA individuals. Genotyping of the discovery cohort showed significant genotypic (p = 0.0005, corrected q-value) as well as allelic (p = 0.005, corrected q-value) associations of rs1342043 with CA in AAs; however, this marker could not be confirmed in either the AA or EA replication sample. Combined analysis of all AA samples (n = 1883) for rs1342043 showed a significant association with CA (genotypic p = 0.0001, allelic p = 0.002) with a gender specific effect for males (allelic p = 0.005, genotypic p = 0.0003). Our data suggest that genetic variants in the NCS-1 gene contribute to susceptibility of CA in individuals of African descent. PMID:22999924

  10. Self-directed exploration provides a Ncs1-dependent learning bonus

    PubMed Central

    Mun, Ho-Suk; Saab, Bechara J.; Ng, Enoch; McGirr, Alexander; Lipina, Tatiana V.; Gondo, Yoichi; Georgiou, John; Roder, John C.

    2015-01-01

    Understanding the mechanisms of memory formation is fundamental to establishing optimal educational practices and restoring cognitive function in brain disease. Here, we show for the first time in a non-primate species, that spatial learning receives a special bonus from self-directed exploration. In contrast, when exploration is escape-oriented, or when the full repertoire of exploratory behaviors is reduced, no learning bonus occurs. These findings permitted the first molecular and cellular examinations into the coupling of exploration to learning. We found elevated expression of neuronal calcium sensor 1 (Ncs1) and dopamine type-2 receptors upon self-directed exploration, in concert with increased neuronal activity in the hippocampal dentate gyrus and area CA3, as well as the nucleus accumbens. We probed further into the learning bonus by developing a point mutant mouse (Ncs1P144S/P144S) harboring a destabilized NCS-1 protein, and found this line lacked the equivalent self-directed exploration learning bonus. Acute knock-down of Ncs1 in the hippocampus also decoupled exploration from efficient learning. These results are potentially relevant for augmenting learning and memory in health and disease, and provide the basis for further molecular and circuit analyses in this direction. PMID:26639399

  11. The Neuronal Calcium Sensor Protein Acrocalcin: A Potential Target of Calmodulin Regulation during Development in the Coral Acropora millepora

    PubMed Central

    Reyes-Bermudez, Alejandro; Miller, David J.; Sprungala, Susanne

    2012-01-01

    To understand the calcium-mediated signalling pathways underlying settlement and metamorphosis in the Scleractinian coral Acropora millepora, a predicted protein set derived from larval cDNAs was scanned for the presence of EF-hand domains (Pfam Id: PF00036). This approach led to the identification of a canonical calmodulin (AmCaM) protein and an uncharacterised member of the Neuronal Calcium Sensor (NCS) family of proteins known here as Acrocalcin (AmAC). While AmCaM transcripts were present throughout development, AmAC transcripts were not detected prior to gastrulation, after which relatively constant mRNA levels were detected until metamorphosis and settlement. The AmAC protein contains an internal CaM-binding site and was shown to interact in vitro with AmCaM. These results are consistent with the idea that AmAC is a target of AmCaM in vivo, suggesting that this interaction may regulate calcium-dependent processes during the development of Acropora millepora. PMID:23284743

  12. Soil calcium and pH monitoring sensor system.

    PubMed

    Lemos, Sherlan G; Nogueira, Ana Rita A; Torre-Neto, André; Parra, Aleix; Alonso, Julian

    2007-06-13

    An agrarian sensorial system based on temperature, moisture, and all solid-state ion-selective potentiometric sensors was developed with the objective of monitoring the behavior of H+ and Ca2+ ions in soil and in real conditions, contributing with a new tool that tries to complement the current precision agriculture technology. The evaluation of the sensorial system to pH monitoring presented a good correlation between the results obtained by the system and the standard methodology, allowing us to notice the soil buffer capacity at different soil depths. With regard to calcium, the sensor system also presented an agreement between its results and those obtained by flame atomic absorption spectrometry, using a calibration model based on multiple linear regressions that allows the correct determination of Ca2+ concentrations in soil depths where the relative moisture is different. In this way, using well-known potentiometric sensors in a complex, discontinued, and heterogeneous matrix, such as soil, the sensorial system proved to be a useful task for agrochemical field applications. PMID:17500528

  13. Network Adaptive Deadband: NCS Data Flow Control for Shared Networks

    PubMed Central

    Díaz-Cacho, Miguel; Delgado, Emma; Prieto, José A. G.; López, Joaquín

    2012-01-01

    This paper proposes a new middleware solution called Network Adaptive Deadband (NAD) for long time operation of Networked Control Systems (NCS) through the Internet or any shared network based on IP technology. The proposed middleware takes into account the network status and the NCS status, to improve the global system performance and to share more effectively the network by several NCS and sensor/actuator data flows. Relationship between network status and NCS status is solved with a TCP-friendly transport flow control protocol and the deadband concept, relating deadband value and transmission throughput. This creates a deadband-based flow control solution. Simulation and experiments in shared networks show that the implemented network adaptive deadband has better performance than an optimal constant deadband solution in the same circumstances. PMID:23208556

  14. Protein-specific localization of a rhodamine-based calcium-sensor in living cells.

    PubMed

    Best, Marcel; Porth, Isabel; Hauke, Sebastian; Braun, Felix; Herten, Dirk-Peter; Wombacher, Richard

    2016-06-28

    A small synthetic calcium sensor that can be site-specifically coupled to proteins in living cells by utilizing the bio-orthogonal HaloTag labeling strategy is presented. We synthesized an iodo-derivatized BAPTA chelator with a tetramethyl rhodamine fluorophore that allows further modification by Sonogashira cross-coupling. The presented calcium sensitive dye shows a 200-fold increase in fluorescence upon calcium binding. The derivatization with an aliphatic linker bearing a terminal haloalkane-function by Sonogashira cross-coupling allows the localization of the calcium sensor to Halo fusion proteins which we successfully demonstrate in in vitro and in vivo experiments. The herein reported highly sensitive tetramethyl rhodamine based calcium indicator, which can be selectively localized to proteins, is a powerful tool to determine changes in calcium levels inside living cells with spatiotemporal resolution. PMID:27072883

  15. Protein intake and calcium absorption – Potential role of the calcium sensor receptor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary protein induces calcium excretion but the source of this calcium is unclear. Evidence from short-term studies indicates that protein promotes bone resorption, but many epidemiologic studies do not corroborate this. Evidence is also mixed on weather protein promotes calcium absorption. Stud...

  16. Generation of a Homozygous Transgenic Rat Strain Stably Expressing a Calcium Sensor Protein for Direct Examination of Calcium Signaling

    PubMed Central

    Szebényi, Kornélia; Füredi, András; Kolacsek, Orsolya; Pergel, Enikő; Bősze, Zsuzsanna; Bender, Balázs; Vajdovich, Péter; Tóvári, József; Homolya, László; Szakács, Gergely; Héja, László; Enyedi, Ágnes; Sarkadi, Balázs; Apáti, Ágota; Orbán, Tamás I.

    2015-01-01

    In drug discovery, prediction of selectivity and toxicity require the evaluation of cellular calcium homeostasis. The rat is a preferred laboratory animal for pharmacology and toxicology studies, while currently no calcium indicator protein expressing rat model is available. We established a transgenic rat strain stably expressing the GCaMP2 fluorescent calcium sensor by a transposon-based methodology. Zygotes were co-injected with mRNA of transposase and a CAG-GCaMP2 expressing construct, and animals with one transgene copy were pre-selected by measuring fluorescence in blood cells. A homozygous rat strain was generated with high sensor protein expression in the heart, kidney, liver, and blood cells. No pathological alterations were found in these animals, and fluorescence measurements in cardiac tissue slices and primary cultures demonstrated the applicability of this system for studying calcium signaling. We show here that the GCaMP2 expressing rat cardiomyocytes allow the prediction of cardiotoxic drug side-effects, and provide evidence for the role of Na+/Ca2+ exchanger and its beneficial pharmacological modulation in cardiac reperfusion. Our data indicate that drug-induced alterations and pathological processes can be followed by using this rat model, suggesting that transgenic rats expressing a calcium-sensitive protein provide a valuable system for pharmacological and toxicological studies. PMID:26234466

  17. Biosensor and chemical sensor probes for calcium and other metal ions

    DOEpatents

    Vo-Dinh, Tuan; Viallet, Pierre

    1996-01-01

    The present invention relates to chemical sensor and biosensor probes for measuring low concentration of metals and metal ions in complex samples such as biological fluids, living cells, and environmental samples. More particularly the present invention relates to a gel-based Indo-1 and Fura-2 chemical sensor probes for the measurement of low concentrations of calcium, cadmium, magnesium and the like. Also disclosed is a detector device using the sensors of the present invention.

  18. Activation of the Endoplasmic Reticulum Calcium Sensor STIM1 and Store-Operated Calcium Entry by Rotavirus Requires NSP4 Viroporin Activity

    PubMed Central

    Hyser, Joseph M.; Utama, Budi; Crawford, Sue E.; Broughman, James R.

    2013-01-01

    Rotavirus nonstructural protein 4 (NSP4) induces dramatic changes in cellular calcium homeostasis. These include increased endoplasmic reticulum (ER) permeability, resulting in decreased ER calcium stores and activation of plasma membrane (PM) calcium influx channels, ultimately causing a 2- to 4-fold elevation in cytoplasmic calcium. Elevated cytoplasmic calcium is absolutely required for virus replication, but the underlying mechanisms responsible for calcium influx remain poorly understood. NSP4 is an ER-localized viroporin, whose activity depletes ER calcium, which ultimately leads to calcium influx. We hypothesized that NSP4-mediated depletion of ER calcium activates store-operated calcium entry (SOCE) through activation of the ER calcium sensor stromal interaction molecule 1 (STIM1). We established and used a stable yellow fluorescent protein-expressing STIM1 cell line (YFP-STIM1) as a biosensor to assess STIM1 activation (puncta formation) by rotavirus infection and NSP4 expression. We found that STIM1 is constitutively active in rotavirus-infected cells and that STIM1 puncta colocalize with the PM-localized Orai1 SOCE calcium channel. Expression of wild-type NSP4 activated STIM1, resulting in PM calcium influx, but an NSP4 viroporin mutant failed to induce STIM1 activation and did not activate the PM calcium entry pathway. Finally, knockdown of STIM1 significantly reduced rotavirus yield, indicating STIM1 plays a critical role in virus replication. These data demonstrate that while rotavirus may ultimately activate multiple calcium channels in the PM, calcium influx is predicated on NSP4 viroporin-mediated activation of STIM1 in the ER. This is the first report of viroporin-mediated activation of SOCE, reinforcing NSP4 as a robust model to understand dysregulation of calcium homeostasis during virus infections. PMID:24109210

  19. Fast calcium sensor proteins for monitoring neural activity

    PubMed Central

    Badura, Aleksandra; Sun, Xiaonan Richard; Giovannucci, Andrea; Lynch, Laura A.; Wang, Samuel S.-H.

    2014-01-01

    Abstract. A major goal of the BRAIN Initiative is the development of technologies to monitor neuronal network activity during active information processing. Toward this goal, genetically encoded calcium indicator proteins have become widely used for reporting activity in preparations ranging from invertebrates to awake mammals. However, slow response times, the narrow sensitivity range of Ca2+ and in some cases, poor signal-to-noise ratio still limit their usefulness. Here, we review recent improvements in the field of neural activity-sensitive probe design with a focus on the GCaMP family of calcium indicator proteins. In this context, we present our newly developed Fast-GCaMPs, which have up to 4-fold accelerated off-responses compared with the next-fastest GCaMP, GCaMP6f. Fast-GCaMPs were designed by destabilizing the association of the hydrophobic pocket of calcium-bound calmodulin with the RS20 binding domain, an intramolecular interaction that protects the green fluorescent protein chromophore. Fast-GCaMP6f-RS06 and Fast-GCaMP6f-RS09 have rapid off-responses in stopped-flow fluorimetry, in neocortical brain slices, and in the intact cerebellum in vivo. Fast-GCaMP6f variants should be useful for tracking action potentials closely spaced in time, and for following neural activity in fast-changing compartments, such as axons and dendrites. Finally, we discuss strategies that may allow tracking of a wider range of neuronal firing rates and improve spike detection. PMID:25558464

  20. CBL1, a calcium sensor that differentially regulates salt, drought, and cold responses in Arabidopsis.

    PubMed

    Cheong, Yong Hwa; Kim, Kyung-Nam; Pandey, Girdhar K; Gupta, Rajeev; Grant, John J; Luan, Sheng

    2003-08-01

    Although calcium is a critical component in the signal transduction pathways that lead to stress gene expression in higher plants, little is known about the molecular mechanism underlying calcium function. It is believed that cellular calcium changes are perceived by sensor molecules, including calcium binding proteins. The calcineurin B-like (CBL) protein family represents a unique group of calcium sensors in plants. A member of the family, CBL1, is highly inducible by multiple stress signals, implicating CBL1 in stress response pathways. When the CBL1 protein level was increased in transgenic Arabidopsis plants, it altered the stress response pathways in these plants. Although drought-induced gene expression was enhanced, gene induction by cold was inhibited. In addition, CBL1-overexpressing plants showed enhanced tolerance to salt and drought but reduced tolerance to freezing. By contrast, cbl1 null mutant plants showed enhanced cold induction and reduced drought induction of stress genes. The mutant plants displayed less tolerance to salt and drought but enhanced tolerance to freezing. These studies suggest that CBL1 functions as a positive regulator of salt and drought responses and a negative regulator of cold response in plants. PMID:12897256

  1. Submicron fiber optic sensors for calcium ions and pH with internal calibration

    NASA Astrophysics Data System (ADS)

    Plaschke, Markus; Geyer, Michael; Reichert, Johannes; Ache, Hans-Joachim

    1997-05-01

    Submicron optical sensors can be prepared by immobilization of fluorescent indicators on tapered fiber tips. However, fluorescence intensity based sensing depends on many parameters (e.g. light source, collection geometry, quenching effects, etc.) and therefore quantification is usually complicated. Ratio measurements are established as a common method to quantify fluorescence signals using a sensing and a reference dye. The sensors described in this work are based on a new immobilization concept which consists of the encapsulation of dextran-linked fluorescence indicators in an organic hydrogel. This concept allows co-immobilization and stable encapsulation of different indicators. The calcium- and pH-sensors presented contain dextran-coupled fluorescein- derivatives as indicators (Calcium GreenTM and fluorescein) and a rhodamine-derivative (Texas RedR) as reference dye, co-immobilized in PolyHEMA. These sensors exhibit a signal stability of several weeks (when stored in buffer solution), fast response times and calibration curves which are not affected by immobilization. Due to the ratio measurement signal reproducibility was less than or equal to 5%. The working lifetime of submicron sensors was limited only by photobleaching of the indicators which can be minimized by reduction of the laser power. The dynamic range and short response times of these sensors suggest applications in physiological fluids, cell cultures or micro-bioreactors.

  2. Calcium

    MedlinePlus

    ... of calcium dietary supplements are carbonate and citrate. Calcium carbonate is inexpensive, but is absorbed best when taken ... antacid products, such as Tums® and Rolaids®, contain calcium carbonate. Each pill or chew provides 200–400 mg ...

  3. Calcium Sensors as Key Hubs in Plant Responses to Biotic and Abiotic Stresses

    PubMed Central

    Ranty, Benoît; Aldon, Didier; Cotelle, Valérie; Galaud, Jean-Philippe; Thuleau, Patrice; Mazars, Christian

    2016-01-01

    The Ca2+ ion is recognized as a crucial second messenger in signaling pathways coupling the perception of environmental stimuli to plant adaptive responses. Indeed, one of the earliest events following the perception of environmental changes (temperature, salt stress, drought, pathogen, or herbivore attack) is intracellular variation of free calcium concentrations. These calcium variations differ in their spatio-temporal characteristics (subcellular location, amplitude, kinetics) with the nature and strength of the stimulus and, for this reason, they are considered as signatures encrypting information from the initial stimulus. This information is believed to drive a specific response by decoding via calcium-binding proteins. Based on recent examples, we illustrate how individual calcium sensors from the calcium-dependent protein kinase and calmodulin-like protein families can integrate inputs from various environmental changes. Focusing on members of these two families, shown to be involved in plant responses to both abiotic and biotic stimuli, we discuss their role as key hubs and we put forward hypotheses explaining how they can drive the signaling pathways toward the appropriate plant responses. PMID:27014336

  4. Differential Nanosecond Protein Dynamics in Homologous Calcium Sensors.

    PubMed

    Robin, Jörg; Brauer, Jens; Sulmann, Stefan; Marino, Valerio; Dell'Orco, Daniele; Lienau, Christoph; Koch, Karl-Wilhelm

    2015-10-16

    Shaping the temporal response of photoreceptors is facilitated by a well-balanced second messenger cascade, in which two neuronal Ca(2+)-sensor proteins operate in a sequential relay mechanism. Although they share structurally similar sensing units, they differentially activate the same target protein. Here, as a prototypical case in Ca(2+)-mediated signal processing, we investigate differential cellular responsiveness in protein conformational dynamics on a nanosecond time scale. For this, we have site-specifically labeled cysteine residues in guanylate cyclase-activating protein GCAP1 by the fluorescent dye Alexa647 and probed its local environment via time-resolved fluorescence spectroscopy. Fluorescence lifetime and rotational anisotropy measurements reveal a distinct structural movement of the polypeptide chain around position 106 upon release of Ca(2+). This is supported by analyzing the diffusional dye motion in a wobbling-in-a-cone model and by molecular dynamics simulations. We conclude that GCAP1 and its cellular cognate GCAP2 operate by distinctly different switching mechanisms despite their high structural homology. PMID:26204433

  5. Calcium

    MedlinePlus

    ... body stores more than 99 percent of its calcium in the bones and teeth to help make and keep them ... in the foods you eat. Foods rich in calcium include Dairy products such as milk, cheese, and yogurt Leafy, green vegetables Fish with soft bones that you eat, such as canned sardines and ...

  6. Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.

    PubMed

    Gonçalves, Letícia Christina Pires; Da Silva, Sandra Maria; DeRose, Paul C; Ando, Rômulo Augusto; Bastos, Erick Leite

    2013-01-01

    In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5) L mol(-1). The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)(+)] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0 × 10(-6) mol L(-1) and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1 ± 0.3)× 10(6) spores mL(-1). This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications. PMID:24019934

  7. Nanodevice-induced conformational and functional changes in a prototypical calcium sensor protein

    NASA Astrophysics Data System (ADS)

    Marino, Valerio; Astegno, Alessandra; Pedroni, Marco; Piccinelli, Fabio; Dell'Orco, Daniele

    2013-12-01

    Calcium (Ca2+) plays a major role in a variety of cellular processes. Fine changes in its concentration are detected by calcium sensor proteins, which adopt specific conformations to regulate their molecular targets. Here, two distinct nanodevices were probed as biocompatible carriers of Ca2+-sensors and the structural and functional effects of protein-nanodevice interactions were investigated. The prototypical Ca2+-sensor recoverin (Rec) was incubated with 20-25 nm CaF2 nanoparticles (NPs) and 70-80 nm liposomes with lipid composition similar to that found in photoreceptor cells. Circular dichroism and fluorescence spectroscopy were used to characterize changes in the protein secondary and tertiary structure and in thermal stability upon interaction with the nanodevice, both in the presence and in the absence of free Ca2+. Variations in the hydrodynamic diameter of the complex were measured by dynamic light scattering and the residual capability of the protein to act as a Ca2+-sensor in the presence of NPs was estimated spectroscopically. The conformation, thermal stability and Ca2+-sensing capability of Rec were all significantly affected by the presence of NPs, while liposomes did not significantly perturb Rec conformation and function, allowing reversible binding. NP-bound Rec maintained an all-helical fold but showed lower thermal stability and high cooperativity of unfolding. Our analysis can be proficiently used to validate the biocompatibility of other nanodevices intended for biomedical applications involving Ca2+-sensors.Calcium (Ca2+) plays a major role in a variety of cellular processes. Fine changes in its concentration are detected by calcium sensor proteins, which adopt specific conformations to regulate their molecular targets. Here, two distinct nanodevices were probed as biocompatible carriers of Ca2+-sensors and the structural and functional effects of protein-nanodevice interactions were investigated. The prototypical Ca2+-sensor recoverin (Rec

  8. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  9. Arabidopsis CML38, a Calcium Sensor That Localizes to Ribonucleoprotein Complexes under Hypoxia Stress1[OPEN

    PubMed Central

    McClintock, Carlee; Li, Tian

    2016-01-01

    During waterlogging and the associated oxygen deprivation stress, plants respond by the induction of adaptive programs, including the redirected expression of gene networks toward the synthesis of core hypoxia-response proteins. Among these core response proteins in Arabidopsis (Arabidopsis thaliana) is the calcium sensor CML38, a protein related to regulator of gene silencing calmodulin-like proteins (rgsCaMs). CML38 transcripts are up-regulated more than 300-fold in roots within 6 h of hypoxia treatment. Transfer DNA insertional mutants of CML38 show an enhanced sensitivity to hypoxia stress, with lowered survival and more severe inhibition of root and shoot growth. By using yellow fluorescent protein (YFP) translational fusions, CML38 protein was found to be localized to cytosolic granule structures similar in morphology to hypoxia-induced stress granules. Immunoprecipitation of CML38 from the roots of hypoxia-challenged transgenic plants harboring CML38pro::CML38:YFP followed by liquid chromatography-tandem mass spectrometry analysis revealed the presence of protein targets associated with messenger RNA ribonucleoprotein (mRNP) complexes including stress granules, which are known to accumulate as messenger RNA storage and triage centers during hypoxia. This finding is further supported by the colocalization of CML38 with the mRNP stress granule marker RNA Binding Protein 47 (RBP47) upon cotransfection of Nicotiana benthamiana leaves. Ruthenium Red treatment results in the loss of CML38 signal in cytosolic granules, suggesting that calcium is necessary for stress granule association. These results confirm that CML38 is a core hypoxia response calcium sensor protein and suggest that it serves as a potential calcium signaling target within stress granules and other mRNPs that accumulate during flooding stress responses. PMID:26634999

  10. Arabidopsis CML38, a Calcium Sensor That Localizes to Ribonucleoprotein Complexes under Hypoxia Stress.

    PubMed

    Lokdarshi, Ansul; Conner, W Craig; McClintock, Carlee; Li, Tian; Roberts, Daniel M

    2016-02-01

    During waterlogging and the associated oxygen deprivation stress, plants respond by the induction of adaptive programs, including the redirected expression of gene networks toward the synthesis of core hypoxia-response proteins. Among these core response proteins in Arabidopsis (Arabidopsis thaliana) is the calcium sensor CML38, a protein related to regulator of gene silencing calmodulin-like proteins (rgsCaMs). CML38 transcripts are up-regulated more than 300-fold in roots within 6 h of hypoxia treatment. Transfer DNA insertional mutants of CML38 show an enhanced sensitivity to hypoxia stress, with lowered survival and more severe inhibition of root and shoot growth. By using yellow fluorescent protein (YFP) translational fusions, CML38 protein was found to be localized to cytosolic granule structures similar in morphology to hypoxia-induced stress granules. Immunoprecipitation of CML38 from the roots of hypoxia-challenged transgenic plants harboring CML38pro::CML38:YFP followed by liquid chromatography-tandem mass spectrometry analysis revealed the presence of protein targets associated with messenger RNA ribonucleoprotein (mRNP) complexes including stress granules, which are known to accumulate as messenger RNA storage and triage centers during hypoxia. This finding is further supported by the colocalization of CML38 with the mRNP stress granule marker RNA Binding Protein 47 (RBP47) upon cotransfection of Nicotiana benthamiana leaves. Ruthenium Red treatment results in the loss of CML38 signal in cytosolic granules, suggesting that calcium is necessary for stress granule association. These results confirm that CML38 is a core hypoxia response calcium sensor protein and suggest that it serves as a potential calcium signaling target within stress granules and other mRNPs that accumulate during flooding stress responses. PMID:26634999

  11. Polyaniline-graphene oxide nanocomposite sensor for quantification of calcium channel blocker levamlodipine.

    PubMed

    Jain, Rajeev; Sinha, Ankita; Khan, Ab Lateef

    2016-08-01

    A novel polyaniline-graphene oxide nanocomposite (PANI/GO/GCE) sensor has been fabricated for quantification of a calcium channel blocker drug levamlodipine (LAMP). Fabricated sensor has been characterized by electrochemical impedance spectroscopy, square wave and cyclic voltammetry, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The developed PANI/GO/GCE sensor has excellent analytical performance towards electrocatalytic oxidation as compared to PANI/GCE, GO/GCE and bare GCE. Under optimized experimental conditions, the fabricated sensor exhibits a linear response for LAMP for its oxidation over a concentration range from 1.25μgmL(-1) to 13.25μgmL(-1) with correlation coefficient of 0.9950 (r(2)), detection limit of 1.07ngmL(-1) and quantification limit of 3.57ngmL(-1). The sensor shows an excellent performance for detecting LAMP with reproducibility of 2.78% relative standard deviation (RSD). The proposed method has been successfully applied for LAMP determination in pharmaceutical formulation with a recovery from 99.88% to 101.75%. PMID:27157745

  12. Synaptotagmin-7 Is an Asynchronous Calcium Sensor for Synaptic Transmission in Neurons Expressing SNAP-23

    PubMed Central

    Weber, Jens P.; Toft-Bertelsen, Trine L.; Mohrmann, Ralf; Delgado-Martinez, Ignacio; Sørensen, Jakob B.

    2014-01-01

    Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs). Use of neurons from double-knock-out (SNAP-25, synaptotagmin-7) mice in combination with viral transduction showed that SNAP-23-driven release is triggered by endogenous synaptotagmin-7. In the absence of synaptotagmin-7 release became even more asynchronous, and the spontaneous release rate increased even more, indicating that synaptotagmin-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein pairs SNAP-25/synaptotagmin-1 and SNAP-23/synaptotagmin-7 might act as mutually exclusive calcium sensors. Expression of fusion proteins between pHluorin (pH-sensitive GFP) and synaptotagmin-1 or -7 showed that vesicles that fuse using the SNAP-23/synaptotagmin-7 combination contained synaptotagmin-1, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity. PMID:25422940

  13. Monitoring of hardening and hygroscopic induced strains in a calcium phosphate bone cement using FBG sensor.

    PubMed

    Bimis, A; Karalekas, D; Bouropoulos, N; Mouzakis, D; Zaoutsos, S

    2016-07-01

    This study initially deals with the investigation of the induced strains during hardening stage of a self-setting calcium phosphate bone cement using fiber-Bragg grating (FBG) optical sensors. A complementary Scanning Electron Microscopy (SEM) investigation was also conducted at different time intervals of the hardening period and its findings were related to the FBG recordings. From the obtained results, it is demonstrated that the FBG response is affected by the microstructural changes taking place when the bone cement is immersed into the hardening liquid media. Subsequently, the FBG sensor was used to monitor the absorption process and hygroscopic response of the hardened and dried biocement when exposed to a liquid/humid environment. From the FBG-based calculated hygric strains as a function of moisture concentration, the coefficient of moisture expansion (CME) of the examined bone cement was obtained, exhibiting two distinct linear regions. PMID:26807773

  14. 47 CFR 216.1 - NCS Directives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL NATIONAL COMMUNICATIONS..., has developed a system of official documents of a referential nature. The documents include NCS... procedures of a continuing nature. The Directives are issued by the Executive Office of the President...

  15. 47 CFR 216.1 - NCS Directives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL NATIONAL COMMUNICATIONS..., has developed a system of official documents of a referential nature. The documents include NCS... procedures of a continuing nature. The Directives are issued by the Executive Office of the President...

  16. 47 CFR 216.1 - NCS Directives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL NATIONAL COMMUNICATIONS..., has developed a system of official documents of a referential nature. The documents include NCS... procedures of a continuing nature. The Directives are issued by the Executive Office of the President...

  17. 47 CFR 216.1 - NCS Directives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL NATIONAL COMMUNICATIONS..., has developed a system of official documents of a referential nature. The documents include NCS... procedures of a continuing nature. The Directives are issued by the Executive Office of the President...

  18. 47 CFR 216.1 - NCS Directives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Telecommunication OFFICE OF SCIENCE AND TECHNOLOGY POLICY AND NATIONAL SECURITY COUNCIL NATIONAL COMMUNICATIONS..., has developed a system of official documents of a referential nature. The documents include NCS... procedures of a continuing nature. The Directives are issued by the Executive Office of the President...

  19. Synthesis of an azido-tagged low affinity ratiometric calcium sensor

    PubMed Central

    Caldwell, Stuart T.; Cairns, Andrew G.; Olson, Marnie; Chalmers, Susan; Sandison, Mairi; Mullen, William; McCarron, John G.; Hartley, Richard C.

    2015-01-01

    Changes in high localised concentrations of Ca2+ ions are fundamental to cell signalling. The synthesis of a dual excitation, ratiometric calcium ion sensor with a Kd of 90 μM, is described. It is tagged with an azido group for bioconjugation, and absorbs in the blue/green and emits in the red region of the visible spectrum with a large Stokes shift. The binding modulating nitro group is introduced to the BAPTA core prior to construction of a benzofuran-2-yl carboxaldehyde by an allylation–oxidation–cyclisation sequence, which is followed by condensation with an azido-tagged thiohydantoin. The thiohydantoin unit has to be protected with an acetoxymethyl (AM) caging group to allow CuAAC click reaction and incorporation of the KDEL peptide endoplasmic reticulum (ER) retention sequence. PMID:26709317

  20. Calmodulin and STIM proteins: Two major calcium sensors in the cytoplasm and endoplasmic reticulum.

    PubMed

    Marshall, Christopher B; Nishikawa, Tadateru; Osawa, Masanori; Stathopulos, Peter B; Ikura, Mitsuhiko

    2015-04-24

    The calcium (Ca(2+)) ion is a universal signalling messenger which plays vital physiological roles in all eukaryotes. To decode highly regulated intracellular Ca(2+) signals, cells have evolved a number of sensor proteins that are ideally adapted to respond to a specific range of Ca(2+) levels. Among many such proteins, calmodulin (CaM) is a multi-functional cytoplasmic Ca(2+) sensor with a remarkable ability to interact with and regulate a plethora of structurally diverse target proteins. CaM achieves this 'multi-talented' functionality through two EF-hand domains, each with an independent capacity to bind targets, and an adaptable flexible linker. By contrast, stromal interaction molecule-1 and -2 (STIMs) have evolved for a specific role in endoplasmic reticulum (ER) Ca(2+) sensing using EF-hand machinery analogous to CaM; however, whereas CaM structurally adjusts to dissimilar binding partners, STIMs use the EF-hand machinery to self-regulate the stability of the Ca(2+) sensing domain. The molecular mechanisms underlying the Ca(2+)-dependent signal transduction by CaM and STIMs have revealed a remarkable repertoire of actions and underscore the flexibility of nature in molecular evolution and adaption to discrete Ca(2+) levels. Recent genomic sequencing efforts have uncovered a number of disease-associated mutations in both CaM and STIM1. This article aims to highlight the most recent key structural and functional findings in the CaM and STIM fields, and discusses how these two Ca(2+) sensor proteins execute their biological functions. PMID:25998729

  1. PyNCS: a microkernel for high-level definition and configuration of neuromorphic electronic systems.

    PubMed

    Stefanini, Fabio; Neftci, Emre O; Sheik, Sadique; Indiveri, Giacomo

    2014-01-01

    Neuromorphic hardware offers an electronic substrate for the realization of asynchronous event-based sensory-motor systems and large-scale spiking neural network architectures. In order to characterize these systems, configure them, and carry out modeling experiments, it is often necessary to interface them to workstations. The software used for this purpose typically consists of a large monolithic block of code which is highly specific to the hardware setup used. While this approach can lead to highly integrated hardware/software systems, it hampers the development of modular and reconfigurable infrastructures thus preventing a rapid evolution of such systems. To alleviate this problem, we propose PyNCS, an open-source front-end for the definition of neural network models that is interfaced to the hardware through a set of Python Application Programming Interfaces (APIs). The design of PyNCS promotes modularity, portability and expandability and separates implementation from hardware description. The high-level front-end that comes with PyNCS includes tools to define neural network models as well as to create, monitor and analyze spiking data. Here we report the design philosophy behind the PyNCS framework and describe its implementation. We demonstrate its functionality with two representative case studies, one using an event-based neuromorphic vision sensor, and one using a set of multi-neuron devices for carrying out a cognitive decision-making task involving state-dependent computation. PyNCS, already applicable to a wide range of existing spike-based neuromorphic setups, will accelerate the development of hybrid software/hardware neuromorphic systems, thanks to its code flexibility. The code is open-source and available online at https://github.com/inincs/pyNCS. PMID:25232314

  2. PyNCS: a microkernel for high-level definition and configuration of neuromorphic electronic systems

    PubMed Central

    Stefanini, Fabio; Neftci, Emre O.; Sheik, Sadique; Indiveri, Giacomo

    2014-01-01

    Neuromorphic hardware offers an electronic substrate for the realization of asynchronous event-based sensory-motor systems and large-scale spiking neural network architectures. In order to characterize these systems, configure them, and carry out modeling experiments, it is often necessary to interface them to workstations. The software used for this purpose typically consists of a large monolithic block of code which is highly specific to the hardware setup used. While this approach can lead to highly integrated hardware/software systems, it hampers the development of modular and reconfigurable infrastructures thus preventing a rapid evolution of such systems. To alleviate this problem, we propose PyNCS, an open-source front-end for the definition of neural network models that is interfaced to the hardware through a set of Python Application Programming Interfaces (APIs). The design of PyNCS promotes modularity, portability and expandability and separates implementation from hardware description. The high-level front-end that comes with PyNCS includes tools to define neural network models as well as to create, monitor and analyze spiking data. Here we report the design philosophy behind the PyNCS framework and describe its implementation. We demonstrate its functionality with two representative case studies, one using an event-based neuromorphic vision sensor, and one using a set of multi-neuron devices for carrying out a cognitive decision-making task involving state-dependent computation. PyNCS, already applicable to a wide range of existing spike-based neuromorphic setups, will accelerate the development of hybrid software/hardware neuromorphic systems, thanks to its code flexibility. The code is open-source and available online at https://github.com/inincs/pyNCS. PMID:25232314

  3. Calcium Binding Promotes Conformational Flexibility of the Neuronal Ca2+ Sensor Synaptotagmin

    PubMed Central

    Bykhovskaia, Maria

    2015-01-01

    Synaptotagmin 1 (Syt1) is a synaptic vesicle protein that serves as a calcium sensor of neuronal secretion. It is established that calcium binding to Syt1 triggers vesicle fusion and release of neuronal transmitters, however, the dynamics of this process is not fully understood. To investigate how Ca2+ binding affects Syt1 conformational dynamics, we performed prolonged molecular dynamics (MD) simulations of Ca2+-unbound and Ca2+-bound forms of Syt1. MD simulations were performed at a microsecond scale and combined with Monte Carlo sampling. We found that in the absence of Ca2+ Syt1 structure in the solution is represented by an ensemble of conformational states with tightly coupled domains. To investigate the effect of Ca2+ binding, we used two different strategies to generate a molecular model of a Ca2+-bound form of Syt1. First, we employed subsequent replacements of monovalent cations transiently captured within Syt1 Ca2+-binding pockets by Ca2+ ions. Second, we performed MD simulations of Syt1 at elevated Ca2+ levels. All the simulations produced Syt1 structures bound to four Ca2+ ions, two ions chelated at the binding pocket of each domain. MD simulations of the Ca2+-bound form of Syt1 revealed that Syt1 conformational flexibility drastically increased upon Ca2+ binding. In the presence of Ca2+, the separation between domains increased, and interdomain rotations became more frequent. These findings suggest that Ca2+ binding to Syt1 may induce major changes in the Syt1 conformational state, which in turn may initiate the fusion process. PMID:25992729

  4. FINAL REPORT: NATIONAL CHILDREN'S STUDY (NCS) ESTIMATING SUBJECT BURDEN FOR POTENTIAL NCS MEASUREMENTS

    EPA Science Inventory

    Purpose The National Children's Study (NCS), a large longitudinal cohort study of environmental exposures among children, is currently in the planning stage. Prior to enrollment of 100,000 pregnant women across the United Sates for this study, a better understanding of the partic...

  5. Functional heterogeneity of the four voltage sensors of a human L-type calcium channel

    PubMed Central

    Pantazis, Antonios; Savalli, Nicoletta; Sigg, Daniel; Neely, Alan; Olcese, Riccardo

    2014-01-01

    Excitation-evoked Ca2+ influx is the fastest and most ubiquitous chemical trigger for cellular processes, including neurotransmitter release, muscle contraction, and gene expression. The voltage dependence and timing of Ca2+ entry are thought to be functions of voltage-gated calcium (CaV) channels composed of a central pore regulated by four nonidentical voltage-sensing domains (VSDs I–IV). Currently, the individual voltage dependence and the contribution to pore opening of each VSD remain largely unknown. Using an optical approach (voltage-clamp fluorometry) to track the movement of the individual voltage sensors, we discovered that the four VSDs of CaV1.2 channels undergo voltage-evoked conformational rearrangements, each exhibiting distinct voltage- and time-dependent properties over a wide range of potentials and kinetics. The voltage dependence and fast kinetic components in the activation of VSDs II and III were compatible with the ionic current properties, suggesting that these voltage sensors are involved in CaV1.2 activation. This view is supported by an obligatory model, in which activation of VSDs II and III is necessary to open the pore. When these data were interpreted in view of an allosteric model, where pore opening is intrinsically independent but biased by VSD activation, VSDs II and III were each found to supply ∼50 meV (∼2 kT), amounting to ∼85% of the total energy, toward stabilizing the open state, with a smaller contribution from VSD I (∼16 meV). VSD IV did not appear to participate in channel opening. PMID:25489110

  6. Porous polymer film calcium ion chemical sensor and method of using the same

    DOEpatents

    Porter, M.D.; Chau, L.K.

    1991-02-12

    A method of measuring calcium ions is disclosed wherein a calcium sensitive reagent, calcichrome, is immobilized on a porous polymer film. The reaction of the calcium sensitive reagent to the Ca(II) is then measured and concentration determined as a function of the reaction. 1 figure.

  7. Porous polymer film calcium ion chemical sensor and method of using the same

    DOEpatents

    Porter, Marc D.; Chau, Lai-Kwan

    1991-02-12

    A method of measuring calcium ions is disclosed wherein a calcium sensitive reagent, calcichrome, is immobilized on a porour polymer film. The reaction of the calcium sensitive reagent to the Ca(II) is then measured and concentration determined as a function of the reaction.

  8. Structural basis for a hand-like site in the calcium sensor CatchER with fast kinetics

    SciTech Connect

    Zhang, Ying; Reddish, Florence; Tang, Shen; Zhuo, You; Wang, Yuan-Fang; Yang, Jenny J.; Weber, Irene T.

    2013-12-01

    High-resolution crystal structures of the designed calcium sensor CatchER revealed snapshots of calcium and gadolinium ions binding within the designed site in agreement with its fast kinetics. Calcium ions, which are important signaling molecules, can be detected in the endoplasmic reticulum by an engineered mutant of green fluorescent protein (GFP) designated CatchER with a fast off-rate. High resolution (1.78–1.20 Å) crystal structures were analyzed for CatchER in the apo form and in complexes with calcium or gadolinium to probe the binding site for metal ions. While CatchER exhibits a 1:1 binding stoichiometry in solution, two positions were observed for each of the metal ions bound within the hand-like site formed by the carboxylate side chains of the mutated residues S147E, S202D, Q204E, F223E and T225E that may be responsible for its fast kinetic properties. Comparison of the structures of CatchER, wild-type GFP and enhanced GFP confirmed that different conformations of Thr203 and Glu222 are associated with the two forms of Tyr66 of the chromophore which are responsible for the absorbance wavelengths of the different proteins. Calcium binding to CatchER may shift the equilibrium for conformational population of the Glu222 side chain and lead to further changes in its optical properties.

  9. Tonoplast calcium sensors CBL2 and CBL3 control plant growth and ion homeostasis through regulating V-ATPase activity in Arabidopsis

    PubMed Central

    Tang, Ren-Jie; Liu, Hua; Yang, Yang; Yang, Lei; Gao, Xiao-Shu; Garcia, Veder J; Luan, Sheng; Zhang, Hong-Xia

    2012-01-01

    Plant responses to developmental and environmental cues are often mediated by calcium (Ca2+) signals that are transmitted by diverse calcium sensors. The calcineurin B-like (CBL) protein family represents calcium sensors that decode calcium signals through specific interactions with a group of CBL-interacting protein kinases. We report functional analysis of Arabidopsis CBL2 and CBL3, two closely related CBL members that are localized to the vacuolar membrane through the N-terminal tonoplast-targeting sequence. While cbl2 or cbl3 single mutant did not show any phenotypic difference from the wild type, the cbl2 cbl3 double mutant was stunted with leaf tip necrosis, underdeveloped roots, shorter siliques and fewer seeds. These defects were reminiscent of those in the vha-a2 vha-a3 double mutant deficient in vacuolar H+-ATPase (V-ATPase). Indeed, the V-ATPase activity was reduced in the cbl2 cbl3 double mutant, connecting tonoplast CBL-type calcium sensors to the regulation of V-ATPase. Furthermore, cbl2 cbl3 double mutant was compromised in ionic tolerance and micronutrient accumulation, consistent with the defect in V-ATPase activity that has been shown to function in ion compartmentalization. Our results suggest that calcium sensors CBL2 and CBL3 serve as molecular links between calcium signaling and V-ATPase, a central regulator of intracellular ion homeostasis. PMID:23184060

  10. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps.

    PubMed

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A S; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-06-01

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K(+) uptake system in the Venus flytrap. In search of K(+) transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K(+)-transporter genes into Xenopus oocytes, however, both putative K(+) transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K(+) transporter 1 (AKT1), we coexpressed the putative K(+) transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K(+) uptake. DmKT1 was found to be a K(+)-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around -120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K(+), reducing its concentration from millimolar levels down to trace levels. PMID:25997445

  11. Calcium sensor kinase activates potassium uptake systems in gland cells of Venus flytraps

    PubMed Central

    Scherzer, Sönke; Böhm, Jennifer; Krol, Elzbieta; Shabala, Lana; Kreuzer, Ines; Larisch, Christina; Bemm, Felix; Al-Rasheid, Khaled A. S.; Shabala, Sergey; Rennenberg, Heinz; Neher, Erwin; Hedrich, Rainer

    2015-01-01

    The Darwin plant Dionaea muscipula is able to grow on mineral-poor soil, because it gains essential nutrients from captured animal prey. Given that no nutrients remain in the trap when it opens after the consumption of an animal meal, we here asked the question of how Dionaea sequesters prey-derived potassium. We show that prey capture triggers expression of a K+ uptake system in the Venus flytrap. In search of K+ transporters endowed with adequate properties for this role, we screened a Dionaea expressed sequence tag (EST) database and identified DmKT1 and DmHAK5 as candidates. On insect and touch hormone stimulation, the number of transcripts of these transporters increased in flytraps. After cRNA injection of K+-transporter genes into Xenopus oocytes, however, both putative K+ transporters remained silent. Assuming that calcium sensor kinases are regulating Arabidopsis K+ transporter 1 (AKT1), we coexpressed the putative K+ transporters with a large set of kinases and identified the CBL9-CIPK23 pair as the major activating complex for both transporters in Dionaea K+ uptake. DmKT1 was found to be a K+-selective channel of voltage-dependent high capacity and low affinity, whereas DmHAK5 was identified as the first, to our knowledge, proton-driven, high-affinity potassium transporter with weak selectivity. When the Venus flytrap is processing its prey, the gland cell membrane potential is maintained around −120 mV, and the apoplast is acidified to pH 3. These conditions in the green stomach formed by the closed flytrap allow DmKT1 and DmHAK5 to acquire prey-derived K+, reducing its concentration from millimolar levels down to trace levels. PMID:25997445

  12. Crystal Structures of the GCaMP Calcium Sensor Reveal the Mechanism of Fluorescence Signal Change and Aid Rational Design

    SciTech Connect

    Akerboom, Jasper; Velez Rivera, Jonathan D.; Rodriguez Guilbe, María M.; Alfaro Malavé, Elisa C.; Hernandez, Hector H.; Tian, Lin; Hires, S. Andrew; Marvin, Jonathan S.; Looger, Loren L.; Schreiter, Eric R.

    2009-03-16

    The genetically encoded calcium indicator GCaMP2 shows promise for neural network activity imaging, but is currently limited by low signal-to-noise ratio. We describe x-ray crystal structures as well as solution biophysical and spectroscopic characterization of GCaMP2 in the calcium-free dark state, and in two calcium-bound bright states: a monomeric form that dominates at intracellular concentrations observed during imaging experiments and an unexpected domain-swapped dimer with decreased fluorescence. This series of structures provides insight into the mechanism of Ca{sup 2+}-induced fluorescence change. Upon calcium binding, the calmodulin (CaM) domain wraps around the M13 peptide, creating a new domain interface between CaM and the circularly permuted enhanced green fluorescent protein domain. Residues from CaM alter the chemical environment of the circularly permuted enhanced green fluorescent protein chromophore and, together with flexible inter-domain linkers, block solvent access to the chromophore. Guided by the crystal structures, we engineered a series of GCaMP2 point mutants to probe the mechanism of GCaMP2 function and characterized one mutant with significantly improved signal-to-noise. The mutation is located at a domain interface and its effect on sensor function could not have been predicted in the absence of structural data.

  13. Redox Modulation of Cellular Signaling and Metabolism Through Reversible Oxidation of Methionine Sensors in Calcium Regulatory Proteins

    SciTech Connect

    Bigelow, Diana J.; Squier, Thomas C.

    2005-01-17

    Adaptive responses associated with environmental stressors are critical to cell survival. These involve the modulation of central signaling protein functions through site-specific and enzymatically reversible oxidative modifications of methionines to coordinate cellular metabolism, energy utilization, and calcium signaling. Under conditions when cellular redox and antioxidant defenses are overwhelmed, the selective oxidation of critical methionines within selected protein sensors functions to down-regulate energy metabolism and the further generation of reactive oxygen species (ROS). Mechanistically, these functional changes within protein sensors take advantage of the helix-breaking character of methionine sulfoxide. Thus, depending on either the ecological niche of the organism or the cellular milieu of different organ systems, cellular metabolism can be fine-tuned to maintain optimal function in the face of variable amounts of collateral oxidative damage. The sensitivity of several calcium regulatory proteins to oxidative modification provides cellular sensors that link oxidative stress to cellular response and recovery. Calmodulin (CaM) is one such critical calcium regulatory protein, which is functionally sensitive to methionine oxidation. Helix destabilization resulting from the oxidation of either Met{sup 144} or Met{sup 145} results in the nonproductive association between CaM and target proteins. The ability of oxidized CaM to stabilize its target proteins in an inhibited state with an affinity similar to that of native (unoxidized) CaM permits this central regulatory protein to function as a cellular rheostat that down-regulates energy metabolism in response to oxidative stress. Likewise, oxidation of a methionine within a critical switch region of the regulatory protein phospholamban is expected to destabilize the phosphorylationdependent helix formation necessary for the release of enzyme inhibition, resulting in a down-regulation of the Ca-ATPase in

  14. Polymorphism in Cs[AgZn(NCS)4].

    PubMed

    Güneş, Minna; Valkonen, Jussi

    2002-12-01

    The title compound, caesium silver zinc tetrathiocyanate, crystallizes in two polymorphic forms, in space groups P2(1)/n and C2/c. Both structures form a continuous three-dimensional network. The structure in C2/c contains a delocalized Ag atom in a binuclear-like anion, where two [Ag(NCS)(4)] units (delocalized Ag as an average) share two common NCS(-) ligands. PMID:12466595

  15. The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory

    PubMed Central

    Reinhard, Judith R.; Kriz, Alexander; Galic, Milos; Angliker, Nico; Rajalu, Mathieu; Vogt, Kaspar E.; Ruegg, Markus A.

    2016-01-01

    Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory. PMID:27194588

  16. The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory.

    PubMed

    Reinhard, Judith R; Kriz, Alexander; Galic, Milos; Angliker, Nico; Rajalu, Mathieu; Vogt, Kaspar E; Ruegg, Markus A

    2016-01-01

    Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory. PMID:27194588

  17. Overlapping functions of stonin 2 and SV2 in sorting of the calcium sensor synaptotagmin 1 to synaptic vesicles

    PubMed Central

    Kaempf, Natalie; Kochlamazashvili, Gaga; Puchkov, Dmytro; Maritzen, Tanja; Bajjalieh, Sandra M.; Kononenko, Natalia L.; Haucke, Volker

    2015-01-01

    Neurotransmission involves the calcium-regulated exocytic fusion of synaptic vesicles (SVs) and the subsequent retrieval of SV membranes followed by reformation of properly sized and shaped SVs. An unresolved question is whether each SV protein is sorted by its own dedicated adaptor or whether sorting is facilitated by association between different SV proteins. We demonstrate that endocytic sorting of the calcium sensor synaptotagmin 1 (Syt1) is mediated by the overlapping activities of the Syt1-associated SV glycoprotein SV2A/B and the endocytic Syt1-adaptor stonin 2 (Stn2). Deletion or knockdown of either SV2A/B or Stn2 results in partial Syt1 loss and missorting of Syt1 to the neuronal surface, whereas deletion of both SV2A/B and Stn2 dramatically exacerbates this phenotype. Selective missorting and degradation of Syt1 in the absence of SV2A/B and Stn2 impairs the efficacy of neurotransmission at hippocampal synapses. These results indicate that endocytic sorting of Syt1 to SVs is mediated by the overlapping activities of SV2A/B and Stn2 and favor a model according to which SV protein sorting is guarded by both cargo-specific mechanisms as well as association between SV proteins. PMID:26015569

  18. Development of calcium zirconate-based hydrogen sensors with oxide reference electrodes for molten aluminum

    NASA Astrophysics Data System (ADS)

    Krishnan, Vivek

    Hydrogen is a major cause of gas porosity in aluminum and is frequently removed from the melt prior to casting. The degassing process can be better controlled if the hydrogen content in the melt is known. Thus, gas sensors which can make continuous in situ measurements in molten aluminum are needed. Current online hydrogen sensing systems are complex designs which are prohibitively expensive. Solid electrolyte based potentiometric sensors have been developed as an attractive alternate. These sensors have traditionally used a gas phase as the reference electrode. The present design has a condensed-phase reference electrode to avoid the need for transport of the reference gas into and out of the melt. The use of an oxide rather than a hydride phase reference is expected to considerably lower device cost and improve shelf life and reliability. The sensor element consists of a solid electrolyte tube based on 10 mol% Indoped CaZrO3, which was synthesized using both solid oxide and oxalate co-precipitation techniques. Precursor oxalate powders prepared using polymeric surfactants (PEG) were characterized using SEM, XRD, FTIR and particle size analysis. PEG was found to reduce particle size and also influence the process of perovskite formation. The oxalate co-precipitation technique enabled powder synthesis at reduced processing time and temperature. Closed-one-end tubes were slip cast and densified for use as solid electrolytes. Impedance spectroscopy and D.C. resistance measurements were made at temperatures between 650 and 900°C. Undoped CaZrO3 was found to be a p-type conductor in air. Indoped CaZrO3 acted as a proton conductor in air and argon+H2O, whereas the material was found to be a p-type conductor in pure argon. While bulk conduction was found to be homogenous with activation energies matching those from D.C. measurements, conduction across the grain boundary was found to be heterogeneous. Potentiometric sensors using In-doped CaZrO3 as the electrolyte, and

  19. Toxicity of 33 NCS to freshwater fish and sea lamprey

    USGS Publications Warehouse

    Marking, Leif L.; King, Everett L.; Walker, Charles R.; Howell, John H.

    1970-01-01

    The chemical 33NCS (3'-chloro-3-nitrosalicylanilide) was evaluated as a fish control agent and as a larvicide for sea lampreys at the Fish Control Laboratories of the Bureau of Sport Fisheries and Wildlife and the Hammond Bay Biological Station of the Bureau of Commercial Fisheries. The chemical is rapidly toxic to many species. Sea lampreys, bowfin, and channel catfish are the most sensitive species. Carp are more sensitive than trouts or sunfishes. Use of 33NCS in selective control of freshwater fishes or sea lampreys requires precise control because its toxicity is strongly influenced by variations in water quality.

  20. CO2/HCO3−- and Calcium-regulated Soluble Adenylyl Cyclase as a Physiological ATP Sensor*

    PubMed Central

    Zippin, Jonathan H.; Chen, Yanqiu; Straub, Susanne G.; Hess, Kenneth C.; Diaz, Ana; Lee, Dana; Tso, Patrick; Holz, George G.; Sharp, Geoffrey W. G.; Levin, Lonny R.; Buck, Jochen

    2013-01-01

    The second messenger molecule cAMP is integral for many physiological processes. In mammalian cells, cAMP can be generated from hormone- and G protein-regulated transmembrane adenylyl cyclases or via the widely expressed and structurally and biochemically distinct enzyme soluble adenylyl cyclase (sAC). sAC activity is uniquely stimulated by bicarbonate ions, and in cells, sAC functions as a physiological carbon dioxide, bicarbonate, and pH sensor. sAC activity is also stimulated by calcium, and its affinity for its substrate ATP suggests that it may be sensitive to physiologically relevant fluctuations in intracellular ATP. We demonstrate here that sAC can function as a cellular ATP sensor. In cells, sAC-generated cAMP reflects alterations in intracellular ATP that do not affect transmembrane AC-generated cAMP. In β cells of the pancreas, glucose metabolism generates ATP, which corresponds to an increase in cAMP, and we show here that sAC is responsible for an ATP-dependent cAMP increase. Glucose metabolism also elicits insulin secretion, and we further show that sAC is necessary for normal glucose-stimulated insulin secretion in vitro and in vivo. PMID:24100033

  1. Fluorescence Lifetime Readouts of Troponin-C-Based Calcium FRET Sensors: A Quantitative Comparison of CFP and mTFP1 as Donor Fluorophores

    PubMed Central

    Laine, Romain; Stuckey, Daniel W.; Manning, Hugh; Warren, Sean C.; Kennedy, Gordon; Carling, David

    2012-01-01

    We have compared the performance of two Troponin-C-based calcium FRET sensors using fluorescence lifetime read-outs. The first sensor, TN-L15, consists of a Troponin-C fragment inserted between CFP and Citrine while the second sensor, called mTFP-TnC-Cit, was realized by replacing CFP in TN-L15 with monomeric Teal Fluorescent Protein (mTFP1). Using cytosol preparations of transiently transfected mammalian cells, we have measured the fluorescence decay profiles of these sensors at controlled concentrations of calcium using time-correlated single photon counting. These data were fitted to discrete exponential decay models using global analysis to determine the FRET efficiency, fraction of donor molecules undergoing FRET and calcium affinity of these sensors. We have also studied the decay profiles of the donor fluorescent proteins alone and determined the sensitivity of the donor lifetime to temperature and emission wavelength. Live-cell fluorescence lifetime imaging (FLIM) of HEK293T cells expressing each of these sensors was also undertaken. We confirmed that donor fluorescence of mTFP-TnC-Cit fits well to a two-component decay model, while the TN-L15 lifetime data was best fitted to a constrained four-component model, which was supported by phasor analysis of the measured lifetime data. If the constrained global fitting is employed, the TN-L15 sensor can provide a larger dynamic range of lifetime readout than the mTFP-TnC-Cit sensor but the CFP donor is significantly more sensitive to changes in temperature and emission wavelength compared to mTFP and, while the mTFP-TnC-Cit solution phase data broadly agreed with measurements in live cells, this was not the case for the TN-L15 sensor. Our titration experiment also indicates that a similar precision in determination of calcium concentration can be achieved with both FRET biosensors when fitting a single exponential donor fluorescence decay model to the fluorescence decay profiles. We therefore suggest that m

  2. Excited-state structural dynamics of a dual-emission calmodulin-green fluorescent protein sensor for calcium ion imaging.

    PubMed

    Oscar, Breland G; Liu, Weimin; Zhao, Yongxin; Tang, Longteng; Wang, Yanli; Campbell, Robert E; Fang, Chong

    2014-07-15

    Fluorescent proteins (FPs) have played a pivotal role in bioimaging and advancing biomedicine. The versatile fluorescence from engineered, genetically encodable FP variants greatly enhances cellular imaging capabilities, which are dictated by excited-state structural dynamics of the embedded chromophore inside the protein pocket. Visualization of the molecular choreography of the photoexcited chromophore requires a spectroscopic technique capable of resolving atomic motions on the intrinsic timescale of femtosecond to picosecond. We use femtosecond stimulated Raman spectroscopy to study the excited-state conformational dynamics of a recently developed FP-calmodulin biosensor, GEM-GECO1, for calcium ion (Ca(2+)) sensing. This study reveals that, in the absence of Ca(2+), the dominant skeletal motion is a ∼ 170 cm(-1) phenol-ring in-plane rocking that facilitates excited-state proton transfer (ESPT) with a time constant of ∼ 30 ps (6 times slower than wild-type GFP) to reach the green fluorescent state. The functional relevance of the motion is corroborated by molecular dynamics simulations. Upon Ca(2+) binding, this in-plane rocking motion diminishes, and blue emission from a trapped photoexcited neutral chromophore dominates because ESPT is inhibited. Fluorescence properties of site-specific protein mutants lend further support to functional roles of key residues including proline 377 in modulating the H-bonding network and fluorescence outcome. These crucial structural dynamics insights will aid rational design in bioengineering to generate versatile, robust, and more sensitive optical sensors to detect Ca(2+) in physiologically relevant environments. PMID:24987121

  3. Calredoxin represents a novel type of calcium-dependent sensor-responder connected to redox regulation in the chloroplast

    PubMed Central

    Hochmal, Ana Karina; Zinzius, Karen; Charoenwattanasatien, Ratana; Gäbelein, Philipp; Mutoh, Risa; Tanaka, Hideaki; Schulze, Stefan; Liu, Gai; Scholz, Martin; Nordhues, André; Offenborn, Jan Niklas; Petroutsos, Dimitris; Finazzi, Giovanni; Fufezan, Christian; Huang, Kaiyao; Kurisu, Genji; Hippler, Michael

    2016-01-01

    Calcium (Ca2+) and redox signalling play important roles in acclimation processes from archaea to eukaryotic organisms. Herein we characterized a unique protein from Chlamydomonas reinhardtii that has the competence to integrate Ca2+- and redox-related signalling. This protein, designated as calredoxin (CRX), combines four Ca2+-binding EF-hands and a thioredoxin (TRX) domain. A crystal structure of CRX, at 1.6 Å resolution, revealed an unusual calmodulin-fold of the Ca2+-binding EF-hands, which is functionally linked via an inter-domain communication path with the enzymatically active TRX domain. CRX is chloroplast-localized and interacted with a chloroplast 2-Cys peroxiredoxin (PRX1). Ca2+-binding to CRX is critical for its TRX activity and for efficient binding and reduction of PRX1. Thereby, CRX represents a new class of Ca2+-dependent ‘sensor-responder' proteins. Genetically engineered Chlamydomonas strains with strongly diminished amounts of CRX revealed altered photosynthetic electron transfer and were affected in oxidative stress response underpinning a function of CRX in stress acclimation. PMID:27297041

  4. Calredoxin represents a novel type of calcium-dependent sensor-responder connected to redox regulation in the chloroplast.

    PubMed

    Hochmal, Ana Karina; Zinzius, Karen; Charoenwattanasatien, Ratana; Gäbelein, Philipp; Mutoh, Risa; Tanaka, Hideaki; Schulze, Stefan; Liu, Gai; Scholz, Martin; Nordhues, André; Offenborn, Jan Niklas; Petroutsos, Dimitris; Finazzi, Giovanni; Fufezan, Christian; Huang, Kaiyao; Kurisu, Genji; Hippler, Michael

    2016-01-01

    Calcium (Ca(2+)) and redox signalling play important roles in acclimation processes from archaea to eukaryotic organisms. Herein we characterized a unique protein from Chlamydomonas reinhardtii that has the competence to integrate Ca(2+)- and redox-related signalling. This protein, designated as calredoxin (CRX), combines four Ca(2+)-binding EF-hands and a thioredoxin (TRX) domain. A crystal structure of CRX, at 1.6 Å resolution, revealed an unusual calmodulin-fold of the Ca(2+)-binding EF-hands, which is functionally linked via an inter-domain communication path with the enzymatically active TRX domain. CRX is chloroplast-localized and interacted with a chloroplast 2-Cys peroxiredoxin (PRX1). Ca(2+)-binding to CRX is critical for its TRX activity and for efficient binding and reduction of PRX1. Thereby, CRX represents a new class of Ca(2+)-dependent 'sensor-responder' proteins. Genetically engineered Chlamydomonas strains with strongly diminished amounts of CRX revealed altered photosynthetic electron transfer and were affected in oxidative stress response underpinning a function of CRX in stress acclimation. PMID:27297041

  5. Genome-wide identification and analyses of the rice calmodulin and related potential calcium sensor proteins

    PubMed Central

    Boonburapong, Bongkoj; Buaboocha, Teerapong

    2007-01-01

    Background A wide range of stimuli evoke rapid and transient increases in [Ca2+]cyt in plant cells which are transmitted by protein sensors that contain EF-hand motifs. Here, a group of Oryza sativa L. genes encoding calmodulin (CaM) and CaM-like (CML) proteins that do not possess functional domains other than the Ca2+-binding EF-hand motifs was analyzed. Results By functional analyses and BLAST searches of the TIGR rice database, a maximum number of 243 proteins that possibly have EF-hand motifs were identified in the rice genome. Using a neighbor-joining tree based on amino acid sequence similarity, five loci were defined as Cam genes and thirty two additional CML genes were identified. Extensive analyses of the gene structures, the chromosome locations, the EF-hand motif organization, expression characteristics including analysis by RT-PCR and a comparative analysis of Cam and CML genes in rice and Arabidopsis are presented. Conclusion Although many proteins have unknown functions, the complexity of this gene family indicates the importance of Ca2+-signals in regulating cellular responses to stimuli and this family of proteins likely plays a critical role as their transducers. PMID:17263873

  6. Bio-NCs - the marriage of ultrasmall metal nanoclusters with biomolecules

    NASA Astrophysics Data System (ADS)

    Goswami, Nirmal; Zheng, Kaiyuan; Xie, Jianping

    2014-10-01

    Ultrasmall metal nanoclusters (NCs) have attracted increasing attention due to their fascinating physicochemical properties. Today, functional metal NCs are finding growing acceptance in biomedical applications. To achieve a better performance in biomedical applications, metal NCs can be interfaced with biomolecules, such as proteins, peptides, and DNA, to form a new class of biomolecule-NC composites (or bio-NCs in short), which typically show synergistic or novel physicochemical and physiological properties. This feature article focuses on the recent studies emerging at the interface of metal NCs and biomolecules, where the interactions could impart unique physicochemical properties to the metal NCs, as well as mutually regulate biological functions of the bio-NCs. In this article, we first provide a broad overview of key concepts and developments in the novel biomolecule-directed synthesis of metal NCs. A special focus is placed on the key roles of biomolecules in metal NC synthesis. In the second part, we describe how the encapsulated metal NCs affect the structure and function of biomolecules. Followed by that, we discuss several unique synergistic effects observed in the bio-NCs, and illustrate them with examples highlighting their potential biomedical applications. Continued interdisciplinary efforts are required to build up in-depth knowledge about the interfacial chemistry and biology of bio-NCs, which could further pave their ways toward biomedical applications.

  7. Single-column purification of the tag-free, recombinant form of the neuronal calcium sensor protein, hippocalcin expressed in Escherichia coli.

    PubMed

    Krishnan, Anuradha; Viviano, Jeffrey; Morozov, Yaroslav; Venkataraman, Venkat

    2016-07-01

    Hippocalcin is a 193 aa protein that is a member of the neuronal calcium sensor protein family, whose functions are regulated by calcium. Mice that lack the function of this protein are compromised in the long term potentiation aspect of memory generation. Recently, mutations in the gene have been linked with dystonia in human. The protein has no intrinsic enzyme activity but is known to bind to variety of target proteins. Very little information is available on how the protein executes its critical role in signaling pathways, except that it is regulated by binding of calcium. Further delineation of its function requires large amounts of pure protein. In this report, we present a single-step purification procedure that yields high quantities of the bacterially expressed, recombinant protein. The procedure may be adapted to purify the protein from inclusion bodies or cytosol in its myristoylated or non-myristoylated forms. MALDI-MS (in source decay) analyses demonstrates that the myristoylation occurs at the glycine residue. The protein is also biologically active as measured through tryptophan fluorescence, mobility shift and guanylate cyclase activity assays. Thus, further analyses of hippocalcin, both structural and functional, need no longer be limited by protein availability. PMID:27001424

  8. Examination of tapered plastic multimode fiber-based sensor performance with silver coating for different concentrations of calcium hypochlorite by soft computing methodologies--a comparative study.

    PubMed

    Zakaria, Rozalina; Sheng, Ong Yong; Wern, Kam; Shamshirband, Shahaboddin; Wahab, Ainuddin Wahid Abdul; Petković, Dalibor; Saboohi, Hadi

    2014-05-01

    A soft methodology study has been applied on tapered plastic multimode sensors. This study basically used tapered plastic multimode fiber [polymethyl methacrylate (PMMA)] optics as a sensor. The tapered PMMA fiber was fabricated using an etching method involving deionized water and acetone to achieve a waist diameter and length of 0.45 and 10 mm, respectively. In addition, a tapered PMMA probe, which was coated by silver film, was fabricated and demonstrated using a calcium hypochlorite (G70) solution. The working mechanism of such a device is based on the observation increment in the transmission of the sensor that is immersed in solutions at high concentrations. As the concentration was varied from 0 to 6 ppm, the output voltage of the sensor increased linearly. The silver film coating increased the sensitivity of the proposed sensor because of the effective cladding refractive index, which increases with the coating and thus allows more light to be transmitted from the tapered fiber. In this study, the polynomial and radial basis function (RBF) were applied as the kernel function of the support vector regression (SVR) to estimate and predict the output voltage response of the sensors with and without silver film according to experimental tests. Instead of minimizing the observed training error, SVR_poly and SVR_rbf were used in an attempt to minimize the generalization error bound so as to achieve generalized performance. An adaptive neuro-fuzzy interference system (ANFIS) approach was also investigated for comparison. The experimental results showed that improvements in the predictive accuracy and capacity for generalization can be achieved by the SVR_poly approach in comparison to the SVR_rbf methodology. The same testing errors were found for the SVR_poly approach and the ANFIS approach. PMID:24979634

  9. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  10. Structural Insights into Membrane Targeting by the Flagellar Calcium-binding Protein (FCaBP) a Myristoylated and Palmitoylated Calcium Sensor in Trypanosoma cruzi

    SciTech Connect

    J Wingard; J Ladner; M Vanarotti; A Fisher; H Robinson; K Buchanan; D Engman; J Ames

    2011-12-31

    The flagellar calcium-binding protein (FCaBP) of the protozoan Trypanosoma cruzi is targeted to the flagellar membrane where it regulates flagellar function and assembly. As a first step toward understanding the Ca{sup 2+}-induced conformational changes important for membrane-targeting, we report here the x-ray crystal structure of FCaBP in the Ca{sup 2+}-free state determined at 2.2{angstrom} resolution. The first 17 residues from the N terminus appear unstructured and solvent-exposed. Residues implicated in membrane targeting (Lys-19, Lys-22, and Lys-25) are flanked by an exposed N-terminal helix (residues 26-37), forming a patch of positive charge on the protein surface that may interact electrostatically with flagellar membrane targets. The four EF-hands in FCaBP each adopt a 'closed conformation' similar to that seen in Ca{sup 2+}-free calmodulin. The overall fold of FCaBP is closest to that of grancalcin and other members of the penta EF-hand superfamily. Unlike the dimeric penta EF-hand proteins, FCaBP lacks a fifth EF-hand and is monomeric. The unstructured N-terminal region of FCaBP suggests that its covalently attached myristoyl group at the N terminus may be solvent-exposed, in contrast to the highly sequestered myristoyl group seen in recoverin and GCAP1. NMR analysis demonstrates that the myristoyl group attached to FCaBP is indeed solvent-exposed in both the Ca{sup 2+}-free and Ca{sup 2+}-bound states, and myristoylation has no effect on protein structure and folding stability. We propose that exposed acyl groups at the N terminus may anchor FCaBP to the flagellar membrane and that Ca{sup 2+}-induced conformational changes may control its binding to membrane-bound protein targets..

  11. Fluorescent gold nanoclusters based photoelectrochemical sensors for detection of H2O2 and glucose.

    PubMed

    Zhang, Jianxiu; Tu, Liping; Zhao, Shuang; Liu, Guohua; Wang, Yangyun; Wang, Yong; Yue, Zhao

    2015-05-15

    In this work, low-toxicity fluorescent gold nanoclusters (AuNCs) based photoelectrochemical sensors were developed for H2O2 and glucose detection. Herein, the processes used to fabricate the sensors and the photoelectrochemical performances of the sensors under different conditions were presented. Based on the energy band levels of the AuNCs and electron tunneling processes, a detailed photoelectrochemical sensing model was given. The designed sensors were then used for H2O2 and glucose detection without any extra modification of the AuNCs or complex enzyme immobilization. The results demonstrate that the AuNCs allow for H2O2 sensing based on their capacity for both fluorescence and catalysis. Indeed, it was observed that H2O2 was catalyzed by the AuNCs and reduced by photoinduced electrons derived from excited AuNCs. Furthermore, an enhancement in photocurrent amplitude followed the increase in the concentrations of H2O2 and glucose. The effects of the types of ligands surrounding the AuNCs and the applied potential on the output photocurrent were well studied to optimize the measurement conditions. The sensitivity and LOD of MUA-AuNCs at -500 mV were 4.33 nA/mM and 35 μM, respectively. All experimental results indicated that AuNCs could not only serve as a promising photoelectrical material for building the photoelectrochemical biosensors but as catalysts for H2O2 sensing. PMID:25190086

  12. Structural basis for a hand-like site in the calcium sensor CatchER with fast kinetics

    PubMed Central

    Zhang, Ying; Reddish, Florence; Tang, Shen; Zhuo, You; Wang, Yuan-Fang; Yang, Jenny J.; Weber, Irene T.

    2013-01-01

    Calcium ions, which are important signaling molecules, can be detected in the endoplasmic reticulum by an engineered mutant of green fluorescent protein (GFP) designated CatchER with a fast off-rate. High resolution (1.78–1.20 Å) crystal structures were analyzed for CatchER in the apo form and in complexes with calcium or gadolinium to probe the binding site for metal ions. While CatchER exhibits a 1:1 binding stoichiometry in solution, two positions were observed for each of the metal ions bound within the hand-like site formed by the carboxylate side chains of the mutated residues S147E, S202D, Q204E, F223E and T225E that may be responsible for its fast kinetic properties. Comparison of the structures of CatchER, wild-type GFP and enhanced GFP confirmed that different conformations of Thr203 and Glu222 are associated with the two forms of Tyr66 of the chromophore which are responsible for the absorbance wavelengths of the different proteins. Calcium binding to CatchER may shift the equilibrium for conformational population of the Glu222 side chain and lead to further changes in its optical properties. PMID:24311573

  13. Calcium - ionized

    MedlinePlus

    ... at both ionized calcium and calcium attached to proteins. You may need to have a separate ionized calcium test if you have factors that increase or decrease total calcium levels. These may include abnormal blood levels ...

  14. Calcium sensor regulation of the CaV2.1 Ca2+ channel contributes to short-term synaptic plasticity in hippocampal neurons.

    PubMed

    Nanou, Evanthia; Sullivan, Jane M; Scheuer, Todd; Catterall, William A

    2016-01-26

    Short-term synaptic plasticity is induced by calcium (Ca(2+)) accumulating in presynaptic nerve terminals during repetitive action potentials. Regulation of voltage-gated CaV2.1 Ca(2+) channels by Ca(2+) sensor proteins induces facilitation of Ca(2+) currents and synaptic facilitation in cultured neurons expressing exogenous CaV2.1 channels. However, it is unknown whether this mechanism contributes to facilitation in native synapses. We introduced the IM-AA mutation into the IQ-like motif (IM) of the Ca(2+) sensor binding site. This mutation does not alter voltage dependence or kinetics of CaV2.1 currents, or frequency or amplitude of spontaneous miniature excitatory postsynaptic currents (mEPSCs); however, synaptic facilitation is completely blocked in excitatory glutamatergic synapses in hippocampal autaptic cultures. In acutely prepared hippocampal slices, frequency and amplitude of mEPSCs and amplitudes of evoked EPSCs are unaltered. In contrast, short-term synaptic facilitation in response to paired stimuli is reduced by ∼ 50%. In the presence of EGTA-AM to prevent global increases in free Ca(2+), the IM-AA mutation completely blocks short-term synaptic facilitation, indicating that synaptic facilitation by brief, local increases in Ca(2+) is dependent upon regulation of CaV2.1 channels by Ca(2+) sensor proteins. In response to trains of action potentials, synaptic facilitation is reduced in IM-AA synapses in initial stimuli, consistent with results of paired-pulse experiments; however, synaptic depression is also delayed, resulting in sustained increases in amplitudes of later EPSCs during trains of 10 stimuli at 10-20 Hz. Evidently, regulation of CaV2.1 channels by CaS proteins is required for normal short-term plasticity and normal encoding of information in native hippocampal synapses. PMID:26755594

  15. Calcium Oscillations

    PubMed Central

    Dupont, Geneviève; Combettes, Laurent; Bird, Gary S.; Putney, James W.

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlying mechanism of calcium oscillations through the power of mathematical modeling. We also summarize recent findings on the role of calcium entry through store-operated channels in sustaining calcium oscillations and in the mechanism by which calcium oscillations couple to downstream effectors. PMID:21421924

  16. Calcium aluminate silicate Ca2Al2SiO7 single crystal applicable to piezoelectric sensors at high temperature

    NASA Astrophysics Data System (ADS)

    Takeda, Hiroaki; Hagiwara, Manabu; Noguchi, Hiroaki; Hoshina, Takuya; Takahashi, Tomoko; Kodama, Nobuhiro; Tsurumi, Takaaki

    2013-06-01

    Ca2Al2SiO7 (CAS) bulk single crystals were grown by the Czochralski method. Material constants of the crystal were determined over the driving temperature range of a typical combustion pressure sensor. The electrical resistivity at 800 °C was found to be of the order of 108 Ωcm. We constructed a measurement system for the direct piezoelectric effect at high temperature, and characterized the crystals in a simulated engine cylinder combustion environment. Output charge signal against applied stress was detected at 700 °C. These observations suggest that CAS crystals are superior candidate materials for high temperature for stress sensing.

  17. A calcium sensor – protein kinase signaling module diversified in plants and is retained in all lineages of Bikonta species

    PubMed Central

    Beckmann, Linda; Edel, Kai H.; Batistič, Oliver; Kudla, Jörg

    2016-01-01

    Calcium (Ca2+) signaling is a universal mechanism of signal transduction and involves Ca2+ signal formation and decoding of information by Ca2+ binding proteins. Calcineurin B-like proteins (CBLs), which upon Ca2+ binding activate CBL-interacting protein kinases (CIPKs) regulate a multitude of physiological processes in plants. Here, we combine phylogenomics and functional analyses to investigate the occurrence and structural conservation of CBL and CIPK proteins in 26 species representing all major clades of eukaryotes. We demonstrate the presence of at least singular CBL-CIPK pairs in representatives of Archaeplastida, Chromalveolates and Excavates and their general absence in Opisthokonta and Amoebozoa. This denotes CBL-CIPK complexes as evolutionary ancient Ca2+ signaling modules that likely evolved in the ancestor of all Bikonta. Furthermore, we functionally characterize the CBLs and CIPK from the parabasalid human pathogen Trichomonas vaginalis. Our results reveal strict evolutionary conservation of functionally important structural features, preservation of biochemical properties and a remarkable cross-kingdom protein-protein interaction potential between CBLs and CIPKs from Arabidopsis thaliana and T. vaginalis. Together our findings suggest an ancient evolutionary origin of a functional CBL-CIPK signaling module close to the root of eukaryotic evolution and provide insights into the initial evolution of signaling networks and Ca2+ signaling specificity. PMID:27538881

  18. A calcium sensor - protein kinase signaling module diversified in plants and is retained in all lineages of Bikonta species.

    PubMed

    Beckmann, Linda; Edel, Kai H; Batistič, Oliver; Kudla, Jörg

    2016-01-01

    Calcium (Ca(2+)) signaling is a universal mechanism of signal transduction and involves Ca(2+) signal formation and decoding of information by Ca(2+) binding proteins. Calcineurin B-like proteins (CBLs), which upon Ca(2+) binding activate CBL-interacting protein kinases (CIPKs) regulate a multitude of physiological processes in plants. Here, we combine phylogenomics and functional analyses to investigate the occurrence and structural conservation of CBL and CIPK proteins in 26 species representing all major clades of eukaryotes. We demonstrate the presence of at least singular CBL-CIPK pairs in representatives of Archaeplastida, Chromalveolates and Excavates and their general absence in Opisthokonta and Amoebozoa. This denotes CBL-CIPK complexes as evolutionary ancient Ca(2+) signaling modules that likely evolved in the ancestor of all Bikonta. Furthermore, we functionally characterize the CBLs and CIPK from the parabasalid human pathogen Trichomonas vaginalis. Our results reveal strict evolutionary conservation of functionally important structural features, preservation of biochemical properties and a remarkable cross-kingdom protein-protein interaction potential between CBLs and CIPKs from Arabidopsis thaliana and T. vaginalis. Together our findings suggest an ancient evolutionary origin of a functional CBL-CIPK signaling module close to the root of eukaryotic evolution and provide insights into the initial evolution of signaling networks and Ca(2+) signaling specificity. PMID:27538881

  19. The National Comorbidity Survey Adolescent Supplement (NCS-A): I. Background and Measures

    PubMed Central

    Merikangas, Kathleen R.; Avenevoli, Shelli; Costello, E. Jane; Koretz, Doreen; Kessler, Ronald C.

    2009-01-01

    Objective This paper presents an overview of the background and measures used in the National Comorbidity Survey Replication Adolescent Supplement (NCS-A). Methods The NCS-A is a national psychiatric epidemiological survey of adolescents ages 13–17. Results The NCS-A was designed to provide the first nationally representative estimates of the prevalence, correlates and patterns of service use for DSM-V mental disorders among US adolescents and to lay the groundwork for follow-up studies of risk-protective factors, consequences, and early expressions of adult mental disorders. The core NCS-A diagnostic interview, the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI), is a fully-structured research diagnostic interview designed for use by trained lay interviewers. A multi-construct, multi-method, multi-informant battery was also included to assess risk and protective factors and barriers to service use. Design limitations due to the NCS-A evolving as a supplement to an ongoing survey of mental disorders of US adults include restricted age range of youth, cross-sectional assessment, and lack of full parental/surrogate informant reports on youth mental disorders and correlates. Conclusions Despite these limitations, the NCS-A contains unparalleled information that can be used to generate national estimates of prevalence and correlates of adolescent mental disorders, risk and protective factors, patterns of service use, and barriers to receiving treatment for these disorders. The retrospective NCS-A data on the development of psychopathology can additionally complement data from longitudinal studies based on more geographically restricted samples and serve as a useful baseline for future prospective studies of the onset and progression of mental disorders in adulthood. PMID:19242382

  20. Calcium Carbonate

    MedlinePlus

    Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not ... for healthy bones, muscles, nervous system, and heart. Calcium carbonate also is used as an antacid to relieve ...

  1. Calcium - urine

    MedlinePlus

    ... best treatment for the most common type of kidney stone , which is made of calcium. This type of ... the kidneys into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production ...

  2. Electrochemical sensors using gold submicron particles modified electrodes based on calcium complexes formed with alizarin red S for determination of Ca(2+) in isolated rat heart mitochondria.

    PubMed

    Yang, Jin-Xiang; He, Yan-Bin; Lai, Li-Na; Li, Jun-Bo; Song, Xiao-Liang

    2015-04-15

    A simple glassy carbon electrode (GCE) modified with gold submicron particles (AuSPs), characterized by a mean diameter of about0.15-0.20μm has been developed. Herein, the complexation reaction of Ca(2+) with alizarin red S (ARS), in 0.1M KOH, has been followed by electrochemical methods using the modified electrode which is able to catalyze the electro-reduction of ARS. When the stoichiometry ratio of Ca(2+) and ARS is 1:2, a new reduction peak at a higher negative potential of -0.975V appeared, and the peak of ARS at -0.815V disappeared. The peak current of ARS in alkaline solution is proportional to the concentration of Ca(2+) in the range 6.0×10(-7)-1.2×10(-4)M with a limit of detection (LOD) of 5.1×10(-7)M. Furthermore, the complex site of Ca(2+) with ARS was analysized by the experimental UV-vis and infrared spectrums and those calculated electronic and vibrational spectroscopies with density functional theory (DFT). The good accordance between theoretical and experimental data confirms that chelation of calcium ion preferentially occurs at the deprotonated catechol site. Then, we implemented an electrochemical assay for the investigation of Ca(2+) in preparations of isolated rat heart mitochondria, which demonstrates the submicron particles modified electrode is a simple and rapid sensor for determining the Ca(2+) in the biological samples. PMID:25497981

  3. Preparation and characterization of bioactive calcium silicate and poly(epsilon-caprolactone) nanocomposite for bone tissue regeneration.

    PubMed

    Wei, Jie; Heo, S J; Liu, Changsheng; Kim, D H; Kim, S E; Hyun, Y T; Shin, Ji-Wang; Shin, Jung-Woog

    2009-09-01

    A novel biocomposite of nanosized calcium silicate (n-CS) and poly(epsilon-caprolactone) (PCL) was successfully fabricated directly using n-CS slurry, not dried n-CS powder, in a solvent-casting method. The in vitro bioactivity of the composite was evaluated by investigating the apatite-forming ability in simulated body fluid. A proliferation assay with mouse L929 fibroblasts was used to test the in vitro biocompatibility. The composition, hydrophilicity, and mechanical properties were also evaluated. Results suggest that the incorporation of n-CS could significantly improve the hydrophilicity, compressive strength, and elastic modulus of n-CS/PCL composites, with the enhancements mainly dependent on n-CS content. The n-CS/PCL composites exhibit excellent in vitro bioactivity, with surface apatite formation for 40% (w/w) n-CS (C40) exceeding that of 20% (w/w) n-CS (C20) at 7 and 14 days. The Ca/P ratios of apatite formed on C20 and C40 surfaces were 1.58 and 1.61, respectively, indicating nonstoichiometric apatite with defective structure. Composites demonstrated significantly better cell attachment and proliferation than that of PCL alone, with C40 demonstrating the best bioactivity. The apatite layers that formed on the composite surfaces facilitated cell attachment (4 h) and proliferation during the early stages (1 and 4 days). Collectively, these results suggest that the incorporation of n-CS produces biocomposites with enhanced bioactivity and biocompatibility. PMID:18563819

  4. Fast doping of Cu into ZnSe NCs by hydrazine promoted cation exchange in aqueous solution at room temperature.

    PubMed

    Shao, Haibao; Wang, Chunlei; Xu, Shuhong; Wang, Zhuyuan; Yin, Haihong; Cui, Yiping

    2015-03-01

    Controllable doping is an effective way of tuning the properties of semiconductor nanocrystals (NCs). In this work, a simple strategy of fast doping Cu ions into ZnSe NCs under ambient conditions was proposed. The principle of doping is based on hydrazine (N2H4) promoted cation exchange reaction. By direct addition of Cu ion stock solution into the preformed ZnSe NCs, Cu doped ZnSe NCs can be obtained. Furthermore, the emission of doped NCs can be tuned by changing the amount of impurity ion addition. The cation exchange reaction is facilitated by three factors: 1) N2H4 addition, 2) fast impurity ions, and 3) partial stabilizer removal. The proposed cation exchange reaction in aqueous solution could be an alternate route for NC doping as well as synthesis of ionic NCs. PMID:25605441

  5. Chloroplast Structure and Function Is Altered in the NCS2 Maize Mitochondrial Mutant 1

    PubMed Central

    Roussell, Deborah L.; Thompson, Deborah L.; Pallardy, Steve G.; Miles, Donald; Newton, Kathleen J.

    1991-01-01

    The nonchromosomal stripe 2 (NCS2) mutant of maize (Zea mays L.) has a DNA rearrangement in the mitochondrial genome that segregates with the abnormal growth phenotype. Yet, the NCS2 characteristic phenotype includes striped sectors of pale-green tissue on the leaves. This suggests a chloroplast abnormality. To characterize the chloroplasts present in the mutant sectors, we examined the chloroplast structure by electron microscopy, chloroplast function by radiolabeled carbon dioxide fixation and fluorescence induction kinetics, and thylakoid protein composition by polyacrylamide gel electrophoresis. The data from these analyses suggest abnormal or prematurely arrested chloroplast development. Deleterious effects of the NCS2 mutant mitochondria upon the cells of the leaf include structural and functional alterations in the both the bundle sheath and mesophyll chloroplasts. ImagesFigure 1Figure 2Figure 3Figure 5Figure 6 PMID:16668157

  6. NICMOS Small ΔT Dewar / NCS PID Model for Orbit Night Power Reduction

    NASA Astrophysics Data System (ADS)

    Wheeler, T.; Robinson, M.

    2005-10-01

    Without SM4 and the installation of new Ni-HB2B batteries, HST is facing a future with decreasing battery capacity. This ISR explores one option for reducing HST’s battery load during orbit night while maintaining the science capability of the NICMOS. Modulating the NCS setpoint temperature, i.e., increasing it during orbit night and decreasing it during orbit day, can accomplish this. A linear NICMOS small ΔT thermal model was developed based on flight data serendipitously obtained during Proposal 10097, NICMOS Temperature Setpoint Darks, to predict camera one’s temperature, NCS compressor speed, and total NCS power for modulations of +/-1, +/-2, and +/-3K. The results are presented.

  7. Toxicity of 33NCS (3'-chloro-3-nitrosalicylanilide) to freshwater fish and sea lampreys

    USGS Publications Warehouse

    Marking, Leif L.; King, Everett L.; Walker, Charles R.; Howell, John H.

    1970-01-01

    The chemical 33NCS (3'-chloro-3-nitrosalicylanilide) was evaluated as a fish control agent and as a larvicide for sea lampreys at the Fish Control Laboratories of the Bureau of Sport Fisheries and Wildlife and the Hammond Bay Biological Station of the Bureau of Commercial Fisheries. The chemical is rapidly toxic to many species. Sea lampreys, bowfin, and channel catfish are the most sensitive species. Carp are more sensitive than trouts or sunfishes. Use of 33NCS in selective control of freshwater fishes or sea lampreys requires precise control because its toxicity is strongly influenced by variations in water quality.

  8. Atomic Resolution of Calcium and Oxygen Sublattices of Calcite in Ambient Conditions by Atomic Force Microscopy Using qPlus Sensors with Sapphire Tips.

    PubMed

    Wastl, Daniel S; Judmann, Michael; Weymouth, Alfred J; Giessibl, Franz J

    2015-01-01

    Characterization and imaging at the atomic scale with atomic force microscopy in biocompatible environments is an ongoing challenge. We demonstrate atomically resolved imaging of the calcite (101̅4) surface plane using stiff quartz cantilevers ("qPlus sensors", stiffness k = 1280 N/m) equipped with sapphire tips in ambient conditions without any surface preparation. With 10 atoms in one surface unit cell, calcite has a highly complex surface structure comprising three different chemical elements (Ca, C, and O). We obtain true atomic resolution of calcite in air at relative humidity ranging from 20% to 40%, imaging atomic steps and single atomic defects. We observe a great durability of sapphire tips with their Mohs hardness of 9, only one step below diamond. Depending on the state of the sapphire tip, we resolve either the calcium or the oxygen sublattice. We determine the tip termination by comparing the experimental images with simulations and discuss the possibility of chemical tip identification in air. The main challenges for imaging arise from the presence of water layers, which form on almost all surfaces and have the potential to dissolve the crystal surface. Frequency shift versus distance spectra show the presence of at least three ordered hydration layers. The measured height of the first hydration layer corresponds well to X-ray diffraction data and molecular dynamic simulations, namely, ∼220 pm. For the following hydration layers we measure ∼380 pm for the second and third layer, ending up in a total hydration layer thickness of at least 1 nm. Understanding the influence of water layers and their structure is important for surface segregation, surface reactions including reconstructions, healing of defects, and corrosion. PMID:25816927

  9. In vivo characterization of NcsB3 to establish the complete biosynthesis of the naphthoic acid moiety of the neocarzinostatin chromophore.

    PubMed

    Hang, Vu Thi Thu; Oh, Tae Jin; Yamaguchi, Tokutaro; Sohng, Jae Kyung

    2010-10-01

    Neocarzinostatin (NCS) is an enediyne antibiotic produced by Streptomyces carzinostaticus. The NCS chromophore consists of an enediyne core, a sugar moiety, and a naphthoic acid (NA) moiety. The latter plays a key role in binding the NCS chromophore to its apoprotein to protect and stabilize the bioactive NCS chromophore. In this study, we expressed three genes: ncsB (naphthoic acid synthase), ncsB3 (P450 hydroxylase), and ncsB1 (O-methyltransferase), in Streptomyces lividans TK24. The three genes were sufficient to produce 2-hydroxy-7-methoxy-5-methyl-1-naphthoic acid. Production was analyzed and confirmed by LC-MS and nuclear magnetic resonance. Here, we report the functional characterization of ncsB3 and thereby elucidate the complete biosynthetic pathway of NA moiety of the NCS chromophore. PMID:20735485

  10. Calcium-binding proteins and development

    NASA Technical Reports Server (NTRS)

    Beckingham, K.; Lu, A. Q.; Andruss, B. F.; McIntire, L. V. (Principal Investigator)

    1998-01-01

    The known roles for calcium-binding proteins in developmental signaling pathways are reviewed. Current information on the calcium-binding characteristics of three classes of cell-surface developmental signaling proteins (EGF-domain proteins, cadherins and integrins) is presented together with an overview of the intracellular pathways downstream of these surface receptors. The developmental roles delineated to date for the universal intracellular calcium sensor, calmodulin, and its targets, and for calcium-binding regulators of the cytoskeleton are also reviewed.

  11. Identity of the Perchlorate Parent Salt(s) at the Phoenix Mars Landing Site Based on Reanalysis of the Calcium Sensor Response

    NASA Astrophysics Data System (ADS)

    Kounaves, S. P.; Folds, K. E.; Hansen, V. M.; Weber, A. W.; Carrier, B. L.; Chaniotakis, N. A.

    2012-12-01

    In 2008 the first comprehensive wet chemical analyses of the martian soil were performed by the Wet Chemistry Laboratory (WCL) on board the Phoenix Mars lander [1-4]. In addition to being dominated by Ca2+ and Mg2+ carbonates, SO4=, and other minor soluble species, the soil contained about 0.6 %wt perchlorate (ClO4-). Its discovery on Mars has broad implications for that planet's water cycle, astrobiology, human habitability, and possible formation of liquid brines. One remaining important question raised by the WCL discovery of ClO4- on Mars is the identity of the parent perchlorate salt. New refined analysis of the Phoenix WCL sensor data and laboratory analyses and equilibrium modeling, indicate that the identity and ratios of the ClO4- parent salts are different than initially proposed. The analyses performed by the Phoenix WCL, along with previous mission results [5], indicated that K+, Na+, Mg2+, Ca2+, or Fe2/3+, either singly or as a mixture, were possible candidate counter cations that could be associated with the amount of ClO4- present in solution. If we assumed 100% association of the ClO4- in the soil, then Ca2+ or Mg2+ could account for 100% in each case, since there is in effect a more than sufficient supply of these two counter cations. For other cations, measured concentrations limit the ClO4- salt potentially present, with Na+ accounting for < 30%, K+ < 5%, and Fe2/3+ < 3%. Clearly, Mg(ClO4)2 or Ca(ClO4)2 could constitute as much as 100% of the perchlorate salt present in the soil, either alone or in combination. To definitively identify the parent salt of the ClO4- detected by WCL, we have; (1) reexamined the original Phoenix WCL data in terms of the perchlorate and calcium sensor response; (2) performed a set of laboratory analyses using a WCL testbed to better understand the behavior of the sensor responses on Mars; and (3) have modeled possible chemical equilibrium and the effect of the perchlorate parent salt on other minerals present. The new

  12. Syntheses, structures and properties of homo- and heterobimetallic complexes of the type [Zn(tren)NCS] 2[M(NCS) 4] [tren = tris(2-aminoethyl)amine; M = Zn, Cu

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Soumi; Bhar, Kishalay; Das, Sumitra; Chantrapromma, Suchada; Fun, Hoong-Kun; Ghosh, Barindra Kumar

    2010-04-01

    A 2:2:1:6 molar ratio of Zn(ClO 4) 2·6H 2O, tris(2-aminoethyl)amine (tren), Zn(ClO 4) 2·6H 2O/Cu(ClO 4) 2·6H 2O and NH 4NCS in methanol-water solution mixtures affords homo-/heterobimetallic compounds of the type [Zn(tren)NCS] 2[M(NCS) 4] (M = Zn, 1; M = Cu, 2) which have been characterized using microanalytical, spectroscopic, magnetic and other physicochemical results. The structures of the compounds are determined by X-ray diffraction measurements. Structural analyses reveal that 1 and 2 are isomorphous and consist of two discrete [Zn(tren)NCS] + cations and a [M(NCS) 4] 2- (M = Zn/Cu) anion. Zinc(II) centers in the [Zn(tren)NCS] + units adopt distorted trigonal bipyramidal geometry with ZnN 5 chromophores coordinated through four N atoms of tren and one N atom of terminal thiocyanate. Each metal(II) center in [M(NCS) 4] 2- has a distorted tetrahedral coordination environment with an MN 4 chromophore ligated by four N atoms of the terminal thiocyanates. In solid state, doubly N-H…S hydrogen bonded 1D chains of [Zn(tren)NCS] + cations are interconnected by tetrahedral [Zn(NCS) 4] 2-/[Cu(NCS) 4] 2- anions through cooperative N-H…S and N-H…N (in 1) and N-H…S and C-H…S (in 2) hydrogen bonds resulting in 3D network structures. Establishment of such networks seems to be aiding the crystallization.

  13. Calcium - urine

    MedlinePlus

    ... into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production of ... Milk-alkali syndrome Proximal renal tubular acidosis Rickets Sarcoidosis Vitamin D Update Date 5/3/2015 Updated ...

  14. Calcium supplements

    MedlinePlus

    ... SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the human body. It helps build and protect your teeth ... absorb calcium. You can get vitamin D from sunlight exposure to your skin and from your diet. Ask your provider whether ...

  15. Heterogeneous Nature of Relaxation Dynamics of Room-Temperature Ionic Liquids (EMIm)2[Co(NCS)4] and (BMIm)2[Co(NCS)4

    DOE PAGESBeta

    Hensel-Bielowka, Stella; Wojnarowska, Zaneta; Dzida, Marzena; Zorębski, Edward; Zorębski, Michał; Geppert-Rybczyńska, Monika; Peppel, Tim; Grzybowska, Katarzyna; Wang, Yangyang; Sokolov, Alexei P.; et al

    2015-08-11

    Dynamic crossover above Tg has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel–Fulcher–Tammann dependence or a breakdown of the Stokes–Einstein and related relations. In this study, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm)2[Co(NCS)4] and (EMIm)2[Co(NCS)4] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observed in the entire studied temperature range. On themore » contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Finally and moreover, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole–Cole function should be used instead.« less

  16. Improvement in γ-hydroxybutyrate-induced contextual fear memory deficit by systemic administration of NCS-382.

    PubMed

    Ishiwari, Keita; Sircar, Ratna

    2016-06-15

    Low, nonsedative doses of γ-hydroxybutyric acid (GHB) produce short-term anterograde amnesia in humans and memory impairments in experimental animals. We have previously shown that acute systemic treatment of GHB in adolescent female rats impairs the acquisition, but not the expression, of contextual fear memory while sparing both the acquisition and the expression of auditory cued fear memory. In the brain, GHB binds to specific GHB-binding sites as well as to γ-aminobutyric acid type B (GABAB) receptors. Although many of the behavioral effects of GHB at high doses have been attributed to its effects on the GABAB receptor, it is unclear which receptor mediates its relatively low-dose memory-impairing effects. The present study examined the ability of the putative GHB receptor antagonist NCS-382 to block the disrupting effects of GHB on fear memory in adolescent rat. Groups of rats received either a single dose of NCS-382 (3-10 mg/kg, intraperitoneally) or vehicle, followed by an injection of either GHB (100 mg/kg, intraperitoneally) or saline. All rats were trained in the fear paradigm, and tested for contextual fear memory and auditory cued fear memory. NCS-382 dose-dependently reversed deficits in the acquisition of contextual fear memory induced by GHB in adolescent rats, with 5 mg/kg of NCS-382 maximally increasing freezing to the context compared with the group administered GHB alone. When animals were tested for cued fear memory, treatment groups did not differ in freezing responses to the tone. These results suggest that low-dose amnesic effects of GHB are mediated by GHB receptors. PMID:27105320

  17. Improvement in γ-hydroxybutyrate-induced contextual fear memory deficit by systemic administration of NCS-382

    PubMed Central

    Ishiwari, Keita

    2016-01-01

    Low, nonsedative doses of γ-hydroxybutyric acid (GHB) produce short-term anterograde amnesia in humans and memory impairments in experimental animals. We have previously shown that acute systemic treatment of GHB in adolescent female rats impairs the acquisition, but not the expression, of contextual fear memory while sparing both the acquisition and the expression of auditory cued fear memory. In the brain, GHB binds to specific GHB-binding sites as well as to γ-aminobutyric acid type B (GABAB) receptors. Although many of the behavioral effects of GHB at high doses have been attributed to its effects on the GABAB receptor, it is unclear which receptor mediates its relatively low-dose memory-impairing effects. The present study examined the ability of the putative GHB receptor antagonist NCS-382 to block the disrupting effects of GHB on fear memory in adolescent rat. Groups of rats received either a single dose of NCS-382 (3–10 mg/kg, intraperitoneally) or vehicle, followed by an injection of either GHB (100 mg/kg, intraperitoneally) or saline. All rats were trained in the fear paradigm, and tested for contextual fear memory and auditory cued fear memory. NCS-382 dose-dependently reversed deficits in the acquisition of contextual fear memory induced by GHB in adolescent rats, with 5 mg/kg of NCS-382 maximally increasing freezing to the context compared with the group administered GHB alone. When animals were tested for cued fear memory, treatment groups did not differ in freezing responses to the tone. These results suggest that low-dose amnesic effects of GHB are mediated by GHB receptors. PMID:27105320

  18. The National Children’s Study (NCS) Establishment and Protection of the Inferential Base

    PubMed Central

    Ellenberg, Jonas H.

    2014-01-01

    SUMMARY The National Children’s Study is a unique study of environment and health that will follow a cohort of 100,000 women from prior to or early in pregnancy and then their children until 21 years of age. The NCS cohort will be a national multi-stage probability sample, using a U.S. Census Bureau geographic sampling frame unrelated to factors that might influence selection into the sample (e.g. access to health care). I present the case for the use of a national probability sample as the design base for the NCS, arguing that selection of the original cohort should be as free from selection bias as possible. The dangers of using a selected or non probability sample approach are demonstrated by an example of its use in outlining the clinical management of children with febrile seizures, an infrequent disorder, which was so wrong for decades. In addition I stress the importance of and the NCS approach to avoiding selection bias that might occur after the initial selection of the cohort. Selection of and maintenance of an unselected cohort is an important element for the validity of inferences in this major undertaking. PMID:20527009

  19. A Calcium-Relay Mechanism in Vertebrate Phototransduction

    PubMed Central

    2013-01-01

    Calcium-signaling in cells requires a fine-tuned system of calcium-transport proteins involving ion channels, exchangers, and ion-pumps but also calcium-sensor proteins and their targets. Thus, control of physiological responses very often depends on incremental changes of the cytoplasmic calcium concentration, which are sensed by calcium-binding proteins and are further transmitted to specific target proteins. This Review will focus on calcium-signaling in vertebrate photoreceptor cells, where recent physiological and biochemical data indicate that a subset of neuronal calcium sensor proteins named guanylate cyclase-activating proteins (GCAPs) operate in a calcium-relay system, namely, to make gradual responses to small changes in calcium. We will further integrate this mechanism in an existing computational model of phototransduction showing that it is consistent and compatible with the dynamics that are characteristic for the precise operation of the phototransduction pathways. PMID:23472635

  20. Calcium antagonists.

    PubMed

    Grossman, Ehud; Messerli, Franz H

    2004-01-01

    Calcium antagonists were introduced for the treatment of hypertension in the 1980s. Their use was subsequently expanded to additional disorders, such as angina pectoris, paroxysmal supraventricular tachycardias, hypertrophic cardiomyopathy, Raynaud phenomenon, pulmonary hypertension, diffuse esophageal spasms, and migraine. Calcium antagonists as a group are heterogeneous and include 3 main classes--phenylalkylamines, benzothiazepines, and dihydropyridines--that differ in their molecular structure, sites and modes of action, and effects on various other cardiovascular functions. Calcium antagonists lower blood pressure mainly through vasodilation and reduction of peripheral resistance. They maintain blood flow to vital organs, and are safe in patients with renal impairment. Unlike diuretics and beta-blockers, calcium antagonists do not impair glucose metabolism or lipid profile and may even attenuate the development of arteriosclerotic lesions. In long-term follow-up, patients treated with calcium antagonists had development of less overt diabetes mellitus than those who were treated with diuretics and beta-blockers. Moreover, calcium antagonists are able to reduce left ventricular mass and are effective in improving anginal pain. Recent prospective randomized studies attested to the beneficial effects of calcium antagonists in hypertensive patients. In comparison with placebo, calcium antagonist-based therapy reduced major cardiovascular events and cardiovascular death significantly in elderly hypertensive patients and in diabetic patients. In several comparative studies in hypertensive patients, treatment with calcium antagonists was equally effective as treatment with diuretics, beta-blockers, or angiotensin-converting enzyme inhibitors. From these studies, it seems that a calcium antagonist-based regimen is superior to other regimens in preventing stroke, equivalent in preventing ischemic heart disease, and inferior in preventing congestive heart failure

  1. Oral administration of iron-saturated bovine lactoferrin–loaded ceramic nanocapsules for breast cancer therapy and influence on iron and calcium metabolism

    PubMed Central

    Mahidhara, Ganesh; Kanwar, Rupinder K; Roy, Kislay; Kanwar, Jagat R

    2015-01-01

    We determined the anticancer efficacy and internalization mechanism of our polymeric–ceramic nanoparticle system (calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate nanocapsules/nanocarriers [ACSC NCs]) loaded with iron-saturated bovine lactoferrin (Fe-bLf) in a breast cancer xenograft model. ACSC-Fe-bLf NCs with an overall size of 322±27.2 nm were synthesized. In vitro internalization and anticancer efficacy were evaluated in the MDA-MB-231 cells using multicellular tumor spheroids, CyQUANT and MTT assays. These NCs were orally delivered in a breast cancer xenograft mice model, and their internalization, cytotoxicity, biodistribution, and anticancer efficacy were evaluated. Chitosan-coated calcium phosphate Fe-bLf NCs effectively (59%, P≤0.005) internalized in a 1-hour period using clathrin-mediated endocytosis (P≤0.05) and energy-mediated pathways (P≤0.05) for internalization; 3.3 mg/mL of ACSC-Fe-bLf NCs completely disintegrated (~130-fold reduction, P≤0.0005) the tumor spheroids in 72 hours and 96 hours. The IC50 values determined for ACSC-Fe-bLf NCs were 1.69 mg/mL at 10 hours and 1.62 mg/mL after 20 hours. We found that Fe-bLf-NCs effectively (P≤0.05) decreased the tumor size (4.8-fold) compared to the void NCs diet and prevented tumor recurrence when compared to intraperitoneal injection of Taxol and Doxorubicin. Receptor gene expression and micro-RNA analysis confirmed upregulation of low-density lipoprotein receptor and transferrin receptor (liver, intestine, and brain). Several micro-RNAs responsible for iron metabolism upregulated with NCs were identified. Taken together, orally delivered Fe-bLf NCs offer enhanced antitumor activity in breast cancer by internalizing via low-density lipoprotein receptor and transferrin receptor and regulating the micro-RNA expression. These NCs also restored the body iron and calcium levels and increased the hematologic counts. PMID:26124661

  2. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  3. Calcium Test

    MedlinePlus

    ... as thyroid disease , parathyroid disorder , malabsorption , cancer, or malnutrition An ionized calcium test may be ordered when ... albumin , which can result from liver disease or malnutrition , both of which may result from alcoholism or ...

  4. Calcium Calculator

    MedlinePlus

    ... with Sarcopenia Skeletal Rare Disorders Data & Publications Facts and Statistics Vitamin D map Fracture Risk Map Hip Fracture ... Training Courses Working Groups Regional Audits Reports Facts and Statistics Popular content Calcium content of common foods What ...

  5. Calcium - ionized

    MedlinePlus

    ... levels. These may include abnormal blood levels of albumin or immunoglobulins. Normal Results Children: 4.8 to ... 2016:chap 245. Read More Acute kidney failure Albumin - blood (serum) test Bone tumor Calcium blood test ...

  6. Phosphorylation of Calcineurin B-like (CBL) Calcium Sensor Proteins by Their CBL-interacting Protein Kinases (CIPKs) Is Required for Full Activity of CBL-CIPK Complexes toward Their Target Proteins*

    PubMed Central

    Hashimoto, Kenji; Eckert, Christian; Anschütz, Uta; Scholz, Martin; Held, Katrin; Waadt, Rainer; Reyer, Antonella; Hippler, Michael; Becker, Dirk; Kudla, Jörg

    2012-01-01

    Calcineurin B-like proteins (CBLs) represent a family of calcium sensor proteins that interact with a group of serine/threonine kinases designated as CBL-interacting protein kinases (CIPKs). CBL-CIPK complexes are crucially involved in relaying plant responses to many environmental signals and in regulating ion fluxes. However, the biochemical characterization of CBL-CIPK complexes has so far been hampered by low activities of recombinant CIPKs. Here, we report on an efficient wheat germ extract-based in vitro transcription/translation protocol that yields active full-length wild-type CIPK proteins. We identified a conserved serine residue within the C terminus of CBLs as being phosphorylated by their interacting CIPKs. Remarkably, our studies revealed that CIPK-dependent CBL phosphorylation is strictly dependent on CBL-CIPK interaction via the CIPK NAF domain. The phosphorylation status of CBLs does not appear to influence the stability, localization, or CIPK interaction of these calcium sensor proteins in general. However, proper phosphorylation of CBL1 is absolutely required for the in vivo activation of the AKT1 K+ channel by CBL1-CIPK23 and CBL9-CIPK23 complexes in oocytes. Moreover, we show that by combining CBL1, CIPK23, and AKT1, we can faithfully reconstitute CBL-dependent enhancement of phosphorylation of target proteins by CIPKs in vitro. In addition, we report that phosphorylation of CBL1 by CIPK23 is also required for the CBL1-dependent enhancement of CIPK23 activity toward its substrate. Together, these data identify a novel general regulatory mechanism of CBL-CIPK complexes in that CBL phosphorylation at their flexible C terminus likely provokes conformational changes that enhance specificity and activity of CBL-CIPK complexes toward their target proteins. PMID:22253446

  7. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables. PMID:26940168

  8. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  9. Calcium Hydroxylapatite

    PubMed Central

    Yutskovskaya, Yana Alexandrovna; Philip Werschler, WM.

    2015-01-01

    Background: Calcium hydroxylapatite is one of the most well-studied dermal fillers worldwide and has been extensively used for the correction of moderate-to-severe facial lines and folds and to replenish lost volume. Objectives: To mark the milestone of 10 years of use in the aesthetic field, this review will consider the evolution of calcium hydroxylapatite in aesthetic medicine, provide a detailed injection protocol for a global facial approach, and examine how the unique properties of calcium hydroxylapatite provide it with an important place in today’s market. Methods: This article is an up-to-date review of calcium hydroxylapatite in aesthetic medicine along with procedures for its use, including a detailed injection protocol for a global facial approach by three expert injectors. Conclusion: Calcium hydroxylapatite is a very effective agent for many areas of facial soft tissue augmentation and is associated with a high and well-established safety profile. Calcium hydroxylapatite combines high elasticity and viscosity with an ability to induce long-term collagen formation making it an ideal agent for a global facial approach. PMID:25610523

  10. Modelling the protocol stack in NCS with deterministic and stochastic petri net

    NASA Astrophysics Data System (ADS)

    Hui, Chen; Chunjie, Zhou; Weifeng, Zhu

    2011-06-01

    Protocol stack is the basis of the networked control systems (NCS). Full or partial reconfiguration of protocol stack offers both optimised communication service and system performance. Nowadays, field testing is unrealistic to determine the performance of reconfigurable protocol stack; and the Petri net formal description technique offers the best combination of intuitive representation, tool support and analytical capabilities. Traditionally, separation between the different layers of the OSI model has been a common practice. Nevertheless, such a layered modelling analysis framework of protocol stack leads to the lack of global optimisation for protocol reconfiguration. In this article, we proposed a general modelling analysis framework for NCS based on the cross-layer concept, which is to establish an efficiency system scheduling model through abstracting the time constraint, the task interrelation, the processor and the bus sub-models from upper and lower layers (application, data link and physical layer). Cross-layer design can help to overcome the inadequacy of global optimisation based on information sharing between protocol layers. To illustrate the framework, we take controller area network (CAN) as a case study. The simulation results of deterministic and stochastic Petri-net (DSPN) model can help us adjust the message scheduling scheme and obtain better system performance.

  11. Visinin-like proteins (VSNLs): interaction partners and emerging functions in signal transduction of a subfamily of neuronal Ca2+-sensor proteins

    PubMed Central

    Braunewell, Karl-Heinz; Klein-Szanto, Andres J.

    2009-01-01

    The visinin-like protein (VSNL) subfamily, including the founder protein VILIP-1, VILIP-2, VILIP-3, hippocalcin and neurocalcin δ, constitute a highly homologous subfamily of neuronal calcium sensor (NCS) proteins. Comparative studies have shown that VSNLs are expressed predominantly in the brain with restricted expression patterns in different subsets of neurons, but are also found in peripheral organs. In addition, the proteins display differences in their calcium affinities, their membrane binding kinetics and in the intracellular targets to which they associate after calcium binding. Even though the proteins use a similar calcium-myristoyl switch mechanism to translocate to cellular membranes, they show calcium-dependent localization to different subcellular compartments when expressed in the same neuron. These distinct calcium-myristoyl switch properties might be explained by specificity for defined phospholipids and membrane-bound targets, which enable VSNLs to modulate various cellular signal transduction pathways, including cyclic nucleotide and MAPK signaling. An emerging theme is the direct or indirect effect of VSNLs on gene expression and the interaction with components of membrane trafficking complexes which may determine a role in membrane trafficking of different receptors and ion channels, such as glutamate receptors of the kainate and AMPA subtype, nicotinic ACh receptors and Ca2+-channels. One hypothesis is that the highly homologous VSNLs have evolved to fulfill specialized functions in membrane trafficking and thereby affect neuronal signaling and differentiation in defined subsets of neurons. VSNLs are involved in differentiation processes showing a tumor invasion suppressor function in peripheral organs. Finally, VSNLs play neuroprotective and neurotoxic roles and have been implicated in neurodegenerative diseases. PMID:18989702

  12. Regiospecific O-methylation of naphthoic acids catalyzed by NcsB1, an O-methyltransferase involved in the biosynthesis of the enediyne antitumor antibiotic neocarzinostatin.

    PubMed

    Luo, Yinggang; Lin, Shuangjun; Zhang, Jian; Cooke, Heather A; Bruner, Steven D; Shen, Ben

    2008-05-23

    Neocarzinostatin, a clinical anticancer drug, is the archetypal member of the chromoprotein family of enediyne antitumor antibiotics that are composed of a nonprotein chromophore and an apoprotein. The neocarzinostatin chromophore consists of a nine-membered enediyne core, a deoxyaminosugar, and a naphthoic acid moiety. We have previously cloned and sequenced the neocarzinostatin biosynthetic gene cluster and proposed that the biosynthesis of the naphthoic acid moiety and its incorporation into the neocarzinostatin chromophore are catalyzed by five enzymes NcsB, NcsB1, NcsB2, NcsB3, and NcsB4. Here we report the biochemical characterization of NcsB1, unveiling that: (i) NcsB1 is an S-adenosyl-L-methionine-dependent O-methyltransferase; (ii) NcsB1 catalyzes regiospecific methylation at the 7-hydroxy group of its native substrate, 2,7-dihydroxy-5-methyl-1-naphthoic acid; (iii) NcsB1 also recognizes other dihydroxynaphthoic acids as substrates and catalyzes regiospecific O-methylation; and (iv) the carboxylate and its ortho-hydroxy groups of the substrate appear to be crucial for NcsB1 substrate recognition and binding, and O-methylation takes place only at the free hydroxy group of these dihydroxynaphthoic acids. These findings establish that NcsB1 catalyzes the third step in the biosynthesis of the naphthoic acid moiety of the neocarzinostatin chromophore and further support the early proposal for the biosynthesis of the naphthoic acid and its incorporation into the neocarzinostatin chromophore with free naphthoic acids serving as intermediates. NcsB1 represents another opportunity that can now be exploited to produce novel neocarzinostatin analogs by engineering neocarzinostatin biosynthesis or applying directed biosynthesis strategies. PMID:18387946

  13. New, high-capacity, calcium-based sorbents: Calcium silicate sorbents. Final report

    SciTech Connect

    Kenney, M.E.; Chiang, Ray-Kuang

    1993-09-30

    A search is being carried out for new calcium-based SO{sub 2} sorbents for induct injection. More specifically, a search is being carried out for induct injection calcium silicate sorbents that are highly cost effective. The objectives of the past year were to study the sorption of SO{sub 2} by representative calcium silicates, to study the composition of the Ca(OH){sub 2}-fly ash sorbent, and to install a humidity sensor in the sorption system.

  14. Exploiting structure similarity in refinement: automated NCS and target-structure restraints in BUSTER

    SciTech Connect

    Smart, Oliver S. Womack, Thomas O.; Flensburg, Claus; Keller, Peter; Paciorek, Włodek; Sharff, Andrew; Vonrhein, Clemens; Bricogne, Gérard

    2012-04-01

    Local structural similarity restraints (LSSR) provide a novel method for exploiting NCS or structural similarity to an external target structure. Two examples are given where BUSTER re-refinement of PDB entries with LSSR produces marked improvements, enabling further structural features to be modelled. Maximum-likelihood X-ray macromolecular structure refinement in BUSTER has been extended with restraints facilitating the exploitation of structural similarity. The similarity can be between two or more chains within the structure being refined, thus favouring NCS, or to a distinct ‘target’ structure that remains fixed during refinement. The local structural similarity restraints (LSSR) approach considers all distances less than 5.5 Å between pairs of atoms in the chain to be restrained. For each, the difference from the distance between the corresponding atoms in the related chain is found. LSSR applies a restraint penalty on each difference. A functional form that reaches a plateau for large differences is used to avoid the restraints distorting parts of the structure that are not similar. Because LSSR are local, there is no need to separate out domains. Some restraint pruning is still necessary, but this has been automated. LSSR have been available to academic users of BUSTER since 2009 with the easy-to-use -autoncs and @@target target.pdb options. The use of LSSR is illustrated in the re-refinement of PDB entries http://scripts.iucr.org/cgi-bin/cr.cgi?rm, where -target enables the correct ligand-binding structure to be found, and http://scripts.iucr.org/cgi-bin/cr.cgi?rm, where -autoncs contributes to the location of an additional copy of the cyclic peptide ligand.

  15. [Mitochondria, calcium homeostasis and calcium signaling].

    PubMed

    Zavodnik, I B

    2016-03-01

    Са2+ is a very important and versatile intracellular signal which controls numerous biochemical and physiological (pathophysiological) processes in the cell. Good evidence exists that mitochondria are sensors, decoders and regulators of calcium signaling. Precise regulation of calcium signaling in the cell involves numerous molecular targets, which induce and decode changes of Са2+ concentrations in the cell (pumps, channels, Са2+-binding proteins, Са2+-dependent enzymes, localized in the cytoplasm and organelles). Mitochondrial Са2+ uniporter accumulates excess of Са2+ in mitochondria, while Na+/Са2+- and H+/Са2+-antiporters extrude Са2+ in the cytoplasm. Mitochondrial Са2+ overloading results in formation of mitochondria permeability transition pores which play an important role in cell death under many pathological conditions. Mitochondria regulate Са2+ homeostasis and control important cellular functions such as metabolism, proliferation, survival. Identification of cellular and mitochondrial Ca2+ transporters and understanding their functional mechanisms open up new prospects for their using as therapeutic targets. PMID:27420625

  16. Calcium and bones

    MedlinePlus

    Bone strength and calcium ... calcium (as well as phosphorus) to make healthy bones. Bones are the main storage site of calcium in ... your body does not absorb enough calcium, your bones can get weak or will not grow properly. ...

  17. Get Enough Calcium

    MedlinePlus

    ... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of calcium ...

  18. Calcium carbonate overdose

    MedlinePlus

    Tums overdose; Calcium overdose ... Calcium carbonate can be dangerous in large amounts. ... Some products that contain calcium carbonate are certain: ... and mineral supplements Other products may also contain calcium ...

  19. Calcium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for calcium cyanide is included in th

  20. Effect of salts, solvents and buffer on miRNA detection using DNA silver nanocluster (DNA/AgNCs) probes.

    PubMed

    Shah, Pratik; Cho, Seok Keun; Thulstrup, Peter Waaben; Bhang, Yong-Joo; Ahn, Jong Cheol; Choi, Suk Won; Rørvig-Lund, Andreas; Yang, Seong Wook

    2014-01-31

    MicroRNAs (miRNAs) are small regulatory RNAs (size ~21 nt to ~25 nt) which regulate a variety of important cellular events in plants, animals and single cell eukaryotes. Especially because of their use in diagnostics of human diseases, efforts have been directed towards the invention of a rapid, simple and sequence selective detection method for miRNAs. Recently, we reported an innovative method for the determination of miRNA levels using the red fluorescent properties of DNA/silver nanoclusters (DNA/AgNCs). Our method is based on monitoring the emission drop of a DNA/AgNCs probe in the presence of its specific target miRNA. Accordingly, the accuracy and efficiency of the method relies on the sensitivity of hybridization between the probe and target. To gain specific and robust hybridization between probe and target, we investigated a range of diverse salts, organic solvents, and buffer to optimize target sensing conditions. Under the newly adjusted conditions, the target sensitivity and the formation of emissive DNA/AgNCs probes were significantly improved. Also, fortification of the Tris-acetate buffer with inorganic salts or organic solvents improved the sensitivity of the DNA/AgNC probes. On the basis of these optimizations, the versatility of the DNA/AgNCs-based miRNA detection method can be expanded. PMID:24393838

  1. 47 CFR 4.13 - Reports by the National Communications System (NCS) and by special offices and facilities, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Reports by the National Communications System (NCS) and by special offices and facilities, and related responsibilities of communications providers. 4.13 Section 4.13 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL DISRUPTIONS TO COMMUNICATIONS Reporting Requirements for...

  2. Effect of salts, solvents and buffer on miRNA detection using DNA silver nanocluster (DNA/AgNCs) probes

    NASA Astrophysics Data System (ADS)

    Shah, Pratik; Cho, Seok Keun; Waaben Thulstrup, Peter; Bhang, Yong-Joo; Ahn, Jong Cheol; Choi, Suk Won; Rørvig-Lund, Andreas; Yang, Seong Wook

    2014-01-01

    MicroRNAs (miRNAs) are small regulatory RNAs (size ˜21 nt to ˜25 nt) which regulate a variety of important cellular events in plants, animals and single cell eukaryotes. Especially because of their use in diagnostics of human diseases, efforts have been directed towards the invention of a rapid, simple and sequence selective detection method for miRNAs. Recently, we reported an innovative method for the determination of miRNA levels using the red fluorescent properties of DNA/silver nanoclusters (DNA/AgNCs). Our method is based on monitoring the emission drop of a DNA/AgNCs probe in the presence of its specific target miRNA. Accordingly, the accuracy and efficiency of the method relies on the sensitivity of hybridization between the probe and target. To gain specific and robust hybridization between probe and target, we investigated a range of diverse salts, organic solvents, and buffer to optimize target sensing conditions. Under the newly adjusted conditions, the target sensitivity and the formation of emissive DNA/AgNCs probes were significantly improved. Also, fortification of the Tris-acetate buffer with inorganic salts or organic solvents improved the sensitivity of the DNA/AgNC probes. On the basis of these optimizations, the versatility of the DNA/AgNCs-based miRNA detection method can be expanded.

  3. Free radical scavenging in vitro and biological activity of diphenyl diselenide-loaded nanocapsules: DPDS-NCS antioxidant and toxicological effects

    PubMed Central

    Stefanello, Sílvio Terra; Dobrachinski, Fernando; de Carvalho, Nélson Rodrigues; Amaral, Guilherme Pires; Barcelos, Rômulo Pillon; Oliveira, Vitor Antunes; Oliveira, Cláudia Sirlene; Giordani, Camila Ferrazza Alves; Pereira, Maria Ester; Rodrigues, Oscar Endrigo Dorneles; Soares, Félix Alexandre Antunes

    2015-01-01

    Selenium compounds, such as diphenyl diselenide (DPDS), have been shown to exhibit biological activity, including antioxidant effects. However, the use of DPDS in pharmacology is limited due to in vivo pro-oxidative effects. In addition, studies have shown that DPDS-loaded nanocapsules (DPDS-NCS) have greater bioavailability than free DPDS in mice. Accordingly, the aim of this study was to investigate the antioxidant properties of DPDS-NCS in vitro and biological activity in mice. Our in vitro results suggested that DPDS-NCS significantly reduced the production of reactive oxygen species and Fe(II)-induced lipid peroxidation (LPO) in brain. The administration of DPDS-NCS did not result in death or change the levels of endogenous reduced or oxidized glutathione after 72 hours of exposure. Moreover, ex vivo assays demonstrated that DPDS-NCS significantly decreased the LPO and reactive oxygen species levels in the brain. In addition, the highest dose of DPDS-NCS significantly reduced Fe(II)- and sodium nitroprusside-induced LPO in the brain and Fe(II)-induced LPO in the liver. Also, δ-aminolevulinate acid dehydratase within the brain was inhibited only in the highest dose of DPDS-NCS. In conclusion, our data demonstrated that DPDS-NCS exhibited low toxicity in mice and have significant antioxidant characteristics, indicating that nanoencapsulation is a safer method of DPDS administration. PMID:26379436

  4. Calcium signaling and cell proliferation.

    PubMed

    Pinto, Mauro Cunha Xavier; Kihara, Alexandre Hiroaki; Goulart, Vânia A M; Tonelli, Fernanda M P; Gomes, Katia N; Ulrich, Henning; Resende, Rodrigo R

    2015-11-01

    Cell proliferation is orchestrated through diverse proteins related to calcium (Ca(2+)) signaling inside the cell. Cellular Ca(2+) influx that occurs first by various mechanisms at the plasma membrane, is then followed by absorption of Ca(2+) ions by mitochondria and endoplasmic reticulum, and, finally, there is a connection of calcium stores to the nucleus. Experimental evidence indicates that the fluctuation of Ca(2+) from the endoplasmic reticulum provides a pivotal and physiological role for cell proliferation. Ca(2+) depletion in the endoplasmatic reticulum triggers Ca(2+) influx across the plasma membrane in an phenomenon called store-operated calcium entries (SOCEs). SOCE is activated through a complex interplay between a Ca(2+) sensor, denominated STIM, localized in the endoplasmic reticulum and a Ca(2+) channel at the cell membrane, denominated Orai. The interplay between STIM and Orai proteins with cell membrane receptors and their role in cell proliferation is discussed in this review. PMID:26275497

  5. Chemical sensors

    SciTech Connect

    Janata, J.; Josowicz, M.; DeVaney, D.M. )

    1994-06-15

    This review of chemical sensors contains the following topics of interest: books and reviews; reviews of sensors by their type; fabrication and selectivity; data processing; thermal sensors; mass sensors (fabrication, gas sensors, and liquid sensors); electrochemical sensors (potentiometric sensors, amperometric sensors, and conductometric sensors); and optical sensors (fabrication, liquid sensors, biosensors, and gas sensors). 795 refs., 1 tab.

  6. Magnetocaloric Evidence for FFLO Superconductivity in κ-(BEDT-TTF)2Cu(NCS)2

    NASA Astrophysics Data System (ADS)

    Fortune, Nathanael; Agosta, Charles; Hannahs, Scott; Park, Ju-Hyun; Gu, Shuyao; Liang, Lucy; Schleuter, John

    We present new magnetocaloric and calorimetric measurements of the high field superconducting state in the layered structure superconductor κ - (BEDT-TTF)2Cu(NCS)2. The strongly field-orientation dependent phase transition between the low field superconducting state and high field superconducting states is first order and is nearly temperature independent, occurring at the Clogston-Chandrasakar paramagnetic limit Hp. Magnetocaloric measurements dT / dH as a function of magnetic field reveal that the system becomes strongly paramagnetic at the cross over from the low field to high field state. At lower temperatures, we are able to resolve small changes at the phase boundary due to the absorption/release of latent heat when increasing/decreasing field, indicating that the high field state is higher entropy than the low field state. These results provide strong new evidence for the formation of paramagnetic spin domains within an inhomogeneous FFLO superconducting state. They also allow us to rule out alternative explanations involving the formation of spin density waves within a homogenous superconducting state. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida.

  7. Giant magnetoresistance in organic superconductors {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}

    SciTech Connect

    Zuo, F.; Schlueter, J.A.; Kelly, M.E.; Williams, J.M.

    1997-08-01

    In this letter, the authors report transport measurements with field and current parallel to the {alpha} axis (perpendicular to the conducting plane) in the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}. The magnetoresistance displays a peak effect as a function of field and temperature with the peak fields increasing linearly with decreasing temperatures. The peak resistance is found to be greater than the normal state value extrapolated from both high and low field measurements. This is a first report of above normal resistance in a superconducting state. The results are in sharp contrast to the conventional dissipation mechanisms in the mixed state for anisotropic superconductors, as in the case of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. They propose a phenomenological model that the peak in the magnetoresistance is caused by a new scattering mechanism due to a strong coupling to the underlying crystal lattice of fluctuating vortices (vortex polarons). The model can semiquantitatively fit the data.

  8. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium ...

  9. Estimation of Magnetic Interactions and Magnetic Structures in Charge-transfer Salts Based on [Cr(isoq)2(NCS)4]- (isoq = Isoquinoline)

    NASA Astrophysics Data System (ADS)

    Katsuhara, Mao; Mori, Takehiko

    2004-12-01

    Magnetic interactions J in [Cr(isoq)2(NCS)4]--based charge-transfer salts, (BDH-TTP)[Cr(isoq)2(NCS)4], (TMTTF)[Cr(isoq)2(NCS)4], and (BO)[Cr(isoq)2(NCS)4], are estimated on the basis of the extended Hückel molecular orbital calculations (BDH-TTP = 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene, BO = bis(ethylenedioxy)-tetrathiafulvalene, TMTTF = tetramethyltetrathiafulvalene, and isoq = isoquinoline). From this, experimental magnetic properties are discussed, and the magnetic structures are determined. (BDH-TTP)[Cr(isoq)2(NCS)4] is composed of two-dimensional array of antiferromagnetically coupled ferrimagnetic chains. These two-dimensional arrays, however, have net magnetic moment perpendicular to the sheets and give rise to weak ferromagnetism. (TMTTF)[Cr(isoq)2(NCS)4] and (BO)[Cr(isoq)2(NCS)4] have similar “body-centered” molecular arrangement. The TMTTF salt has considerable πd-interaction in two directions, and this compound actually shows a magnetic transition. The BO salt has large πd-interaction only in one direction, but the frustrating dd- and ππ-interactions are considerably large. Consequently, this compound does not exhibit a magnetic transition.

  10. Calcium in Plants

    PubMed Central

    WHITE, PHILIP J.; BROADLEY, MARTIN R.

    2003-01-01

    Calcium is an essential plant nutrient. It is required for various structural roles in the cell wall and membranes, it is a counter‐cation for inorganic and organic anions in the vacuole, and the cytosolic Ca2+ concentration ([Ca2+]cyt) is an obligate intracellular messenger coordinating responses to numerous developmental cues and environmental challenges. This article provides an overview of the nutritional requirements of different plants for Ca, and how this impacts on natural flora and the Ca content of crops. It also reviews recent work on (a) the mechanisms of Ca2+ transport across cellular membranes, (b) understanding the origins and specificity of [Ca2+]cyt signals and (c) characterizing the cellular [Ca2+]cyt‐sensors (such as calmodulin, calcineurin B‐like proteins and calcium‐dependent protein kinases) that allow plant cells to respond appropriately to [Ca2+]cyt signals. PMID:12933363

  11. Calcium and bones (image)

    MedlinePlus

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human ... body, are continually being re-formed and incorporate calcium into their structure. Calcium is essential for the ...

  12. Calcium source (image)

    MedlinePlus

    Getting enough calcium to keep bones from thinning throughout a person's life may be made more difficult if that person has ... as a tendency toward kidney stones, for avoiding calcium-rich food sources. Calcium deficiency also effects the ...

  13. Coronary Calcium Scan

    MedlinePlus

    ... the NHLBI on Twitter. What Is a Coronary Calcium Scan? A coronary calcium scan is a test ... you have calcifications in your coronary arteries. Coronary Calcium Scan Figure A shows the position of the ...

  14. Calcium hydroxide poisoning

    MedlinePlus

    Hydrate - calcium; Lime milk; Slaked lime ... Calcium hydroxide ... These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement ...

  15. First order vortex phase transition in the organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}

    SciTech Connect

    Inada, M.; Sasaki, T.; Nishizaki, T.; Kobayashi, N.; Yamada, S.; Fukase, T.

    1999-12-01

    The local magnetic induction is measured in the quasi-two dimensional organic superconductor {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2} by using a micro Hall probe. The small step is observed on the temperature dependence of the local magnetic induction. This result implies the existence of the first-order phase transition of the vortex system in this organic superconductor as is already reported in high-{Tc} oxide and other organic superconductors.

  16. Synthesis and magnetic studies of the {π }-d ferrimagnet TTF[ Cr(NCS){4}(1,10'-phenanthroline)] , TTF = tetrathiafulvalene

    NASA Astrophysics Data System (ADS)

    Turner, S. S.; Carling, S. G.; Day, P.; Gómez-Garcia, C. J.; Coronado, E.

    2004-04-01

    A new synthesis route to the π -d ferrimagnet TTF[ Cr(NCS){4}(1,10'-phenanthroline)] is described along with recent magnetic investigations. In particular the variable frequency AC magnetisation of the protonated and fully deuterated samples indicate no frequency dependence and a Tc of 8.7 K. Single crystal heat capacity and muon spin relaxation experiments show a second magnetic transition at 2.4 K. Key words. Charge-transfer salts, conductivity, ferrimagnetism.

  17. AC susceptibility and critical current in the organic superconductor {kappa}-(ET){sub 2}Cu(NCS){sub 2}

    SciTech Connect

    Gonzalez, M.A.; Velez, M.; Vicent, J.L.; Schleuter, J.; Williams, J.M.; Crabtree, G.W.

    1994-05-01

    The AC susceptibility (X{prime}, X{double_prime}) has bee measured in a single crystal of the organic superconductor K-(ET){sub 2}Cu(NCS){sub 2} ({Tc} = 9.5 K) as a function of the DC magnetic field, for several frequencies (10 {sup 2} Hz

  18. Optimizing radiolabeling amine-functionalized silica nanoparticles using SarAr-NCS for applications in imaging and radiotherapy.

    PubMed

    Kong, Linggen; Mume, Eskender; Triani, Gerry; Smith, Suzanne V

    2013-05-01

    Silica nanoparticles functionalized with amine groups and in the size range of approximately 60-94 nm were produced by combining sol-gel processing and emulsion technology. Hexa-aza cage ligand SarAr-NCS was conjugated to the silica nanoparticles and subsequently radiolabeled with a solution of (57)Co(2+)-doped carrier Co(2+). The number of Co(2+) ions bound to the silica particles at pH 7 was used to determine the average number of available SarAr-NCS ligands conjugated to a silica particle. For organically modified silica particles of 94.0 and 59.5 nm diameter, the maximum number of metal binding sites was determined to be 11700 and 3270 sites per particle, respectively. For silica particles (63.5 nm peak diameter) produced using an water-in-oil emulsion, the calculated average was 4480 on the particle surface. The number of SarAr-NCS conjugated on the particles was easily controlled, potentially providing for a range of products for applications in the risk assessment of particles and theranostic imaging or radiotherapy when radiolabeled with a suitable radioisotope such as (64)Cu or (67)Cu. PMID:23581487

  19. A theoretical study on the interstellar synthesis of H{sub 2}NCS{sup +} and HNCSH{sup +} cations

    SciTech Connect

    Gronowski, Marcin; Kołos, Robert E-mail: rkolos@ichf.edu.pl

    2014-09-10

    HNCS and NCSH molecules, recently discovered in the interstellar medium, are likely formed via the dissociative recombination of H{sub 2}NCS{sup +} or HNCSH{sup +} isomeric ions. Interstellar synthesis of the latter is discussed on theoretical grounds. The analysis of relevant potential energy surfaces suggests a key role for chemical processes in which CSH{sup +} or HCS{sup +} cations (most likely formed in CS+H{sub 3}{sup +} collisions) react with NH{sub 2} or NH{sub 3}. The astrochemical kinetic database (kida.uva.2011), appended with 7 sulfur-bearing molecules and 48 corresponding reactions, has been applied to model the evolution of HNCS, NCSH, and their cationic precursors in a quiescent molecular cloud. Based on the model and on spectroscopic predictions, for an object like TMC-1, we expect the total intensity of H{sub 2}NCS{sup +} microwave lines to be comparable to that observed for HSCN. Theoretically derived molecular parameters, of interest for radio spectroscopy, are given for the most stable cations sharing the H{sub 2}NCS{sup +} stoichiometry.

  20. Nanocrystals of Fe(phen)2(NCS)2 and the size-dependent spin-crossover characteristics.

    PubMed

    Laisney, J; Tissot, A; Molnár, G; Rechignat, L; Rivière, E; Brisset, F; Bousseksou, A; Boillot, M-L

    2015-10-21

    We report on the size reduction of the neutral Fe(phen)2(NCS)2 prototypical compound exhibiting a cooperative spin-crossover associated with a first-order phase transition (at ca. 176 K). We use the [Fe(phen)3](NCS)2 ionic precursor and the solvent-assisted precipitation technique to prepare an array of crystalline objects with sizes varying over two orders of magnitude (from 15 up to 1400 nm). TEM, X-ray diffraction and IR measurements provide evidences for the formation of particles of neutral and ionic species, which results from the interplay between the relevant chemical equilibrium and the reaction kinetics (ligand extraction, complex precipitation), and the modulation of the latter by physico-chemical parameters. A thermal transformation of diamagnetic nanocrystals of [Fe(phen)3](NCS)2 leads to spin-crossover particles of Fe(phen)2(NCS)2 of a comparable size. Powders of nano-, micro- and polycrystals of Fe(phen)2(NCS)2 present X-ray diffractograms typical of the so-called polymorph II. The importance of size effects on the cooperative spin-crossover process was probed with magnetic, Mössbauer, Raman and IR spectroscopic measurements. Each sample exhibits spin-state switching of the Fe(ii) ions. The salient features are: a cooperativity preserved at the micrometric scale, a very limited downshift of the transition temperature and an asymmetric spreading of the thermal process (over ca. 100 K) with the size reduction. At temperatures close to room temperature, the process appears to be quasi complete whatever the size of the samples. This result, extracted from Raman data, was confirmed by Mössbauer measurements in the case of the largest objects (LS residue <5-10% for bulk and microparticles). Below 150 K, a very efficient low-spin to high-spin photoexcitation was induced by the Raman laser beam in all the samples which prevents the extraction of the high-spin fraction in this temperature range. However variable temperature IR spectra of the 29 nm particles

  1. Towards the chemical control of molecular packing: syntheses and crystal structures of three trans-[NiL4(NCS)2] complexes.

    PubMed

    Soliman, Saied M; Elzawy, Zahia B; Abu-Youssef, Morsy A M; Albering, Jörg; Gatterer, Karl; Ohrström, Lars; Kettle, Sidney F A

    2014-02-01

    Three nickel(II) isothiocyanato complexes of the formula trans-[NiL4(NCS)2] (L = ethylisonicotinate, methylisonicotinate and 4-benzoylpyridine) have been prepared: [Ni(ethylisonicotinate)4(NCS)2] (I), [Ni(methylisonicotinate)4(NCS)2] (II) and [Ni(4-benzoylpyridine)4(NCS)2] (III). All three complexes are monomeric and have a distorted octahedral geometry around Ni(II). Despite their apparent molecular similarity, the crystal density of (III) (1.454 g cm(-3)) is significantly higher than that of (I) and (II) (both 1.408 g cm(-3)), suggesting that the molecular packing is most efficient in (III). A study of the molecular Hirshfeld surfaces, together with density functional theory (DFT) calculations, provide insights into the origin of the molecular packing features, and it is suggested that the greater crystal density of (III) results from smaller intermolecular electrostatic repulsions. PMID:24441134

  2. A visual physiological temperature sensor developed with gelatin-stabilized luminescent silver nanoclusters.

    PubMed

    Lan, Jing; Zou, Hongyan; Liu, Zexi; Gao, Mingxuan; Chen, Binbin; Li, Yuanfang; Huang, Chengzhi

    2015-10-01

    A visual physiological temperature sensor was successfully developed with newly hydrothermally prepared fluorescent silver nanoclusters (AgNCs) at room temperature using gelatin as the protective and reducing agent. The as-prepared gelatin-stabilized AgNCs was water-soluble, uniform and exhibited a narrow distribution with an average size of 1.16 nm, showing a maximum emission band at 552 nm (2.45 eV) when excited at 445 nm (2.79 eV). The large Stokes shift of 110 nm of the gelatin-stabilized AgNCs makes it actually applicable with very low background and light scattering interferences. It was found that the as-prepared gelatin-stabilized AgNCs is temperature-sensitive over the range from 5°C to 45°C, and thus a visual physiological temperature sensor could be developed with the gelatin-AgNCs as under the irradiation of visible light. PMID:26078186

  3. DFT structural investigation on Fe(1,10-phenanthroline){sub 2} (NCS){sub 2} spin crossover molecule

    SciTech Connect

    Chiş, V.; Isai, R.; Droghetti, A.; Rungger, I.; Sanvito, S.; Morari, C.

    2013-11-13

    Understanding the coupling of spin crossover molecules to metallic surfaces is a key ingredient for harnessing of their remarkable features for future spintronics applications. Here we investigate the structural and electronic properties of deformed Fe(1,10-phenanthroline){sub 2} (NCS){sub 2} molecules, mimicking the possible effects arising from the interaction with a metallic substrate. We find a relatively large structural flexibility for this molecule, accompanied by small changes in their total energy. This suggests that the spin crossover activity can be modulated by the interaction with the substrate.

  4. Nature and mechanism of the photoinduced spin transition in [Fe(PM-BiA){sub 2}(NCS){sub 2}

    SciTech Connect

    Ichiyanagi, K.; Hebert, J.; Toupet, L.; Cailleau, H.; Collet, E.

    2006-02-01

    We report the investigation of a prototype cooperative photoinduced spin transition in [Fe(PM-BiA){sub 2}(NCS){sub 2}] by x-ray diffraction. The structural rearrangement accompanying the change of an electronic state between the low spin and the photoinduced out-of-equilibrium high spin phases is similar to the one occurring around the phase transition at thermal equilibrium. The cooperative behavior of the light-induced optical hysteresis and light-induced thermal hysteresis phenomena investigated here show a strong similarity with thermal hysteresis around first-order phase transitions, since they are driven by a domain nucleation process.

  5. Extracellular calcium sensing and extracellular calcium signaling

    NASA Technical Reports Server (NTRS)

    Brown, E. M.; MacLeod, R. J.; O'Malley, B. W. (Principal Investigator)

    2001-01-01

    , localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

  6. Calcium/calmodulin-mediated signal network in plants

    NASA Technical Reports Server (NTRS)

    Yang, Tianbao; Poovaiah, B. W.

    2003-01-01

    Various extracellular stimuli elicit specific calcium signatures that can be recognized by different calcium sensors. Calmodulin, the predominant calcium receptor, is one of the best-characterized calcium sensors in eukaryotes. In recent years, completion of the Arabidopsis genome project and advances in functional genomics have helped to identify and characterize numerous calmodulin-binding proteins in plants. There are some similarities in Ca(2+)/calmodulin-mediated signaling in plants and animals. However, plants possess multiple calmodulin genes and many calmodulin target proteins, including unique protein kinases and transcription factors. Some of these proteins are likely to act as "hubs" during calcium signal transduction. Hence, a better understanding of the function of these calmodulin target proteins should help in deciphering the Ca(2+)/calmodulin-mediated signal network and its role in plant growth, development and response to environmental stimuli.

  7. Heterogeneous Nature of Relaxation Dynamics of Room-Temperature Ionic Liquids (EMIm)2[Co(NCS)4] and (BMIm)2[Co(NCS)4

    SciTech Connect

    Hensel-Bielowka, Stella; Wojnarowska, Zaneta; Dzida, Marzena; Zorębski, Edward; Zorębski, Michał; Geppert-Rybczyńska, Monika; Peppel, Tim; Grzybowska, Katarzyna; Wang, Yangyang; Sokolov, Alexei P.; Paluch, Marian

    2015-08-11

    Dynamic crossover above Tg has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel–Fulcher–Tammann dependence or a breakdown of the Stokes–Einstein and related relations. In this study, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm)2[Co(NCS)4] and (EMIm)2[Co(NCS)4] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observed in the entire studied temperature range. On the contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Finally and moreover, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole–Cole function should be used instead.

  8. Single-source-precursor synthesis of hafnium-containing ultrahigh-temperature ceramic nanocomposites (UHTC-NCs).

    PubMed

    Yuan, Jia; Hapis, Stefania; Breitzke, Hergen; Xu, Yeping; Fasel, Claudia; Kleebe, Hans-Joachim; Buntkowsky, Gerd; Riedel, Ralf; Ionescu, Emanuel

    2014-10-01

    Amorphous SiHfBCN ceramics were prepared from a commercial polysilazane (HTT 1800, AZ-EM), which was modified upon reactions with Hf(NEt2)4 and BH3·SMe2, and subsequently cross-linked and pyrolyzed. The prepared materials were investigated with respect to their chemical and phase composition, by means of spectroscopy techniques (Fourier transform infrared (FTIR), Raman, magic-angle spinning nuclear magnetic resonance (MAS NMR)), as well as X-ray diffraction (XRD) and transmission electron microscopy (TEM). Annealing experiments of the SiHfBCN samples in an inert gas atmosphere (Ar, N2) at temperatures in the range of 1300-1700 °C showed the conversion of the amorphous materials into nanostructured UHTC-NCs. Depending on the annealing atmosphere, HfC/HfB2/SiC (annealing in argon) and HfN/Si3N4/SiBCN (annealing in nitrogen) nanocomposites were obtained. The results emphasize that the conversion of the single-phase SiHfBCN into UHTC-NCs is thermodynamically controlled, thus allowing for a knowledge-based preparative path toward nanostructured ultrahigh-temperature stable materials with adjusted compositions. PMID:25231931

  9. Towards Understanding Quantum Monodromy in Quasi-Symmetric Molecules: Fassst Rotational Spectra of CH_3NCO and CH_3NCS

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Fortman, Sarah; Medvedev, Ivan R.; Winnewisser, Manfred; De Lucia, Frank C.; Koput, Jacek

    2010-06-01

    The recent studies of the rotational spectrum of the NCNCS molecule demonstrated the success of quantum monodromy in describing the quasilinear behavior of this molecule, inclusive of the abrupt transition of spectroscopic behavior from the bent to the linear molecule regime. Similar, quasisymmetric behaviour, is known to be present in symmetric top molecules, and has been studied at lowest-J transitions for two such molecules, CH_3NCO and CH_3NCS. Further progress requires more experimental data and presently we report FASSST rotational spectra of CH_3NCO and CH_3NCS. The spectra provide practically continuous 117-376 GHz coverage and are very rich, since the ladder of excited vibrational states associated with the qusilinear bending coordinate is multiplied by the nearly free internal rotation of the methyl group. Initial stages of the analysis leading up to an analysis in an extension of the framework used for NCNCS are described. B.P.Winnewisser, et al., Phys. Rev. Lett. 95. 243002 (2005). M.Winnewisser, et al., J. Mol. Struct. 798, 1 {2006}. B.P.Winnewisser, et al., Phys. Chem. Chem. Phys. DOI:10.1039/B922023B (2010). J.Koput, J. Mol. Spectrosc. 115, 131 (1986) J.Koput, J. Mol. Spectrosc. 118, 189 (1986)

  10. [Do cows drink calcium?].

    PubMed

    Geishauser, T; Lechner, S; Plate, I; Heidemann, B

    2008-03-01

    The objective of this study was to investigate how well cows drink the Propeller calcium drink, and it's effect on blood calcium concentration. Drinking was tested in 120 cows right after calving, before cows drank anything else. 60 cows each were offered 20 liters of Propeller calcium drink or 20 liters of water. Cows drank the Propeller as good as water. 72% of all cows drank all 20 liters, 18% drank on average 8.2 liters and 10% drank less than 1 liter. Blood calcium concentration was studied in 16 cows right after calving. Eight cows each were offered 20 liters of Propeller calcium drink or no calcium drink. Blood calcium significantly increased ten minutes after Propeller intake and stayed significantly elevated for 24 hours. Without calcium drink blood calcium levels decreased significantly. Advantages of the new Propeller calcium drink over calcium gels or boli could be that cows now drink calcium themselves and that the Propeller increases blood calcium concentration rapidly and long lasting. PMID:18429501

  11. Calcium and Vitamin D

    MedlinePlus

    ... to your weekly shopping list. Produce Serving Size Estimated Calcium* Collard greens, frozen 8 oz 360 mg ... Oranges 1 whole 55 mg Seafood Serving Size Estimated Calcium* Sardines, canned with bones 3 oz 325 ...

  12. Fenoprofen calcium overdose

    MedlinePlus

    ... page: //medlineplus.gov/ency/article/002649.htm Fenoprofen calcium overdose To use the sharing features on this page, please enable JavaScript. Fenoprofen calcium is a type of medicine called a nonsteroidal ...

  13. Calcium channel blocker overdose

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/002580.htm Calcium channel blocker overdose To use the sharing features on this page, please enable JavaScript. Calcium channel blockers are a type of medicine used ...

  14. Fenoprofen calcium overdose

    MedlinePlus

    Fenoprofen calcium is a type of medicine called a nonsteroidal anti-inflammatory drug. It is a prescription pain medicine used to relieve symptoms of arthritis . Fenoprofen calcium overdose occurs when someone takes more than the ...

  15. Calcium and bones (image)

    MedlinePlus

    Calcium is one of the most important minerals for the growth, maintenance, and reproduction of the human body. Bones, like other tissues in the body, are continually being re-formed and incorporate calcium into their ...

  16. Calcium and magnesium disorders.

    PubMed

    Goff, Jesse P

    2014-07-01

    Hypocalcemia is a clinical disorder that can be life threatening to the cow (milk fever) and predisposes the animal to various other metabolic and infectious disorders. Calcium homeostasis is mediated primarily by parathyroid hormone, which stimulates bone calcium resorption and renal calcium reabsorption. Parathyroid hormone stimulates the production of 1,25-dihydroxyvitamin D to enhance diet calcium absorption. High dietary cation-anion difference interferes with tissue sensitivity to parathyroid hormone. Hypomagnesemia reduces tissue response to parathyroid hormone. PMID:24980727

  17. Calcium and Mitosis

    NASA Technical Reports Server (NTRS)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  18. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter describes the roles of calcium and vitamin D in bone health. Calcium is required for the bone formation phase of bone remodeling and it also affects bone mass through its impact on the remodeling rate. Typically, about 5 nmol (200 mg) of calcium is removed from the adult skeleton and ...

  19. Calcium and bones

    MedlinePlus

    Bone strength and calcium ... or if your body does not absorb enough calcium, your bones can get weak or will not grow properly. ... injury. As you age, your body still needs calcium to keep your bones dense and strong. Most experts recommend at least ...

  20. A "turn-on" silver nanocluster based fluorescent sensor for folate receptor detection and cancer cell imaging under visual analysis.

    PubMed

    Jiang, Hong; Xu, Gang; Sun, Yimin; Zheng, Weiwei; Zhu, Xiangxiang; Wang, Baojuan; Zhang, Xiaojun; Wang, Guangfeng

    2015-07-28

    A novel terminal protection based label-free and "turn-on" fluorescent sensor for detection of folate receptors (FRs) and HeLa cells is developed by fluorescence resonance energy transfer (FRET) between single-walled carbon nanotubes (SWCNTs) and silver nanoclusters (AgNCs). Multilevel visual analysis (m(2)VA) was firstly proposed and applied in optimizing the experimental parameters. PMID:26108636

  1. Multiscale Experimental and Theoretical Investigations of Spin Crossover FeII Complexes: Examples of [Fe(phen)2(NCS)2] and [Fe(PM-BiA)2(NCS)2

    PubMed Central

    Matar, Samir F.; Guionneau, Philippe; Chastanet, Guillaume

    2015-01-01

    For spin crossover (SCO) complexes, computation results are reported and confirmed with experiments at multiscale levels of the isolated molecule and extended solid on the one hand and theory on the other hand. The SCO phenomenon which characterizes organometallics based on divalent iron in an octahedral FeN6-like environment with high spin (HS) and low spin (LS) states involves the LS/HS switching at the cost of small energies provided by temperature, pressure or light, the latter connected with Light-Induced Excited Spin-State Trapping (LIESST) process. Characteristic infra red (IR) and Raman vibration frequencies are computed within density functional theory (DFT) framework. In [Fe(phen)2(NCS)2] a connection of selected frequencies is established with an ultra-fast light-induced LS → HS photoswitching mechanism. In the extended solid, density of state DOS and electron localization function (ELF) are established for both LS and HS forms, leading to characterizion of the compound as an insulator in both spin states with larger gaps for LS configuration, while keeping molecular features in the solid. In [Fe(PM-BiA)2(NCS)2], by combining DFT and classical molecular dynamics, the properties and the domains of existence of the different phases are obtained by expressing the potential energy surfaces in a short range potential for Fe–N interactions. Applying such Fe–N potentials inserted in a classical force field and carrying out molecular dynamics (MD) in so-called “semi-classical MD” calculations, lead to the relative energies of HS/LS configurations of the crystal and to the assessment of the experimental (P, T) phase diagram. PMID:25686037

  2. Multiscale experimental and theoretical investigations of spin crossover Fe(II) complexes: examples of [Fe(phen)2(NCS)2] and [Fe(PM-BiA)2(NCS)2].

    PubMed

    Matar, Samir F; Guionneau, Philippe; Chastanet, Guillaume

    2015-01-01

    For spin crossover (SCO) complexes, computation results are reported and confirmed with experiments at multiscale levels of the isolated molecule and extended solid on the one hand and theory on the other hand. The SCO phenomenon which characterizes organometallics based on divalent iron in an octahedral FeN6-like environment with high spin (HS) and low spin (LS) states involves the LS/HS switching at the cost of small energies provided by temperature, pressure or light, the latter connected with Light-Induced Excited Spin-State Trapping (LIESST) process. Characteristic infra red (IR) and Raman vibration frequencies are computed within density functional theory (DFT) framework. In [Fe(phen)2(NCS)2] a connection of selected frequencies is established with an ultra-fast light-induced LS → HS photoswitching mechanism. In the extended solid, density of state DOS and electron localization function (ELF) are established for both LS and HS forms, leading to characterizion of the compound as an insulator in both spin states with larger gaps for LS configuration, while keeping molecular features in the solid. In [Fe(PM-BiA)2(NCS)2], by combining DFT and classical molecular dynamics, the properties and the domains of existence of the different phases are obtained by expressing the potential energy surfaces in a short range potential for Fe-N interactions. Applying such Fe-N potentials inserted in a classical force field and carrying out molecular dynamics (MD) in so-called "semi-classical MD" calculations, lead to the relative energies of HS/LS configurations of the crystal and to the assessment of the experimental (P, T) phase diagram. PMID:25686037

  3. Calcium bioavailability from calcium fortified food products.

    PubMed

    Kohls, K

    1991-08-01

    The calcium balance of 12 presumed healthy human young adult subjects was assessed. Subjects consumed a constant laboratory-controlled diet supplemented with one of four calcium-fortified food products: orange juice (OJ), milk (M), experimental pasteurized processed cheese (T), soda (S), or a calcium carbonate plus vitamin D tablet (CC). Study length was 6 weeks with seven-day experimental periods (2-days allowed for adjustment with 5-days combined for purposes of analysis). All urine and fecal samples were collected by the subjects for the duration of the study. Blood samples were drawn at the end of each experimental period. Urine and fecal calcium contents were determined. Blood samples were analyzed for alkaline phosphatase. Results of this study indicate a higher fecal calcium content (mg/day) when subjects consumed CC and T, and when subjects consumed self-selected diets, than when given S, M, or OJ. Urinary calcium excretion was significantly lower when subjects consumed OJ than when they consumed M, T, or their self-selected diets. A significantly larger positive calcium balance was demonstrated when subjects consumed OJ as compared to T. Fecal transmit time did not vary significantly. Serum alkaline phosphatase was significantly lower when subjects consumed T than when they consumed self-selected diets. PMID:1765836

  4. Synthesis, crystal structure and luminescence properties of one inorganic-organic hybrid compound [FTMA] 2[Co(NCS) 4] (FTMA = ferrocenylmethyltrimethylammonium cation)

    NASA Astrophysics Data System (ADS)

    Bai, Yan; Zhang, Guo-Qiang; Dang, Dong-Bin; Ma, Peng-Tao; Niu, Jing-Yang

    2011-08-01

    A new inorganic-organic hybrid compound [FTMA] 2[Co(NCS) 4] (FTMA = ferrocenylmethyltrimethylammonium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Co(II) atom has a distorted tetrahedral environment with four N atoms of four NCS - anions. In the solid state there are C-H⋯π interactions between adjacent ferrocenyl cations, which generate one-dimensional (1-D) supramolecular chain, and C-H⋯S hydrogen bonds between [FTMA] + cations and cobalt thiocyanate anions. The title compound shows strong purple fluorescence emission in the solid state at room temperature.

  5. Synthesis, crystal structure and luminescence properties of one inorganic-organic hybrid compound [FTMA]2[Co(NCS)4] (FTMA = ferrocenylmethyltrimethylammonium cation).

    PubMed

    Bai, Yan; Zhang, Guo-Qiang; Dang, Dong-Bin; Ma, Peng-Tao; Niu, Jing-Yang

    2011-08-01

    A new inorganic-organic hybrid compound [FTMA](2)[Co(NCS)(4)] (FTMA = ferrocenylmethyltrimethylammonium cation) has been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Co(II) atom has a distorted tetrahedral environment with four N atoms of four NCS(-) anions. In the solid state there are C-H⋯π interactions between adjacent ferrocenyl cations, which generate one-dimensional (1-D) supramolecular chain, and C-H⋯S hydrogen bonds between [FTMA](+) cations and cobalt thiocyanate anions. The title compound shows strong purple fluorescence emission in the solid state at room temperature. PMID:21530374

  6. Density functional plus dynamical mean-field theory of the spin-crossover molecule Fe(phen)2(NCS)2

    NASA Astrophysics Data System (ADS)

    Chen, Jia; Millis, Andrew J.; Marianetti, Chris A.

    2015-06-01

    We study the spin-crossover molecule Fe(phen) 2(NCS) 2 using density functional theory (DFT) plus dynamical mean-field theory, which allows access to observables not attainable with traditional quantum chemical or electronic structure methods. The temperature dependent magnetic susceptibility, electron addition and removal spectra, and total energies are calculated and compared to experiment. We demonstrate that the proper quantitative energy difference between the high-spin and low-spin state, as well as reasonably accurate values of the magnetic susceptibility can be obtained when using reasonable interaction parameters. Comparisons to DFT and DFT+U calculations demonstrate that dynamical correlations are critical to the energetics of the low-spin state. Additionally, we elucidate the differences between DFT+U and spin density functional theory (SDFT) plus U methodologies, demonstrating that DFT+U can recover SDFT+U results for an appropriately chosen on-site exchange interaction.

  7. Matrix-assisted relaxation in Fe(phen)2(NCS)2 spin-crossover microparticles, experimental and theoretical investigations

    NASA Astrophysics Data System (ADS)

    Enachescu, Cristian; Tanasa, Radu; Stancu, Alexandru; Tissot, Antoine; Laisney, Jérôme; Boillot, Marie-Laure

    2016-07-01

    In this study, we present the influence of the embedding matrix on the relaxation of Fe(phen)2(NCS)2 (phen = 1,10-phenanthroline) spin-transition microparticles as revealed by experiments and provide an explanation within the framework of an elastic model based on a Monte-Carlo method. Experiments show that the shape of the high-spin → low-spin relaxation curves is drastically changed when the particles are dispersed in glycerol. This effect was considered in the model by means of interactions between the microparticles and the matrix. A faster start of the relaxation for microparticles embedded in glycerol is due to an initial positive local pressure acting on the edge spin-crossover molecules from the matrix side. This local pressure diminishes and eventually becomes negative during relaxation, as an effect of the decrease of the volume of spin-crossover microparticles from high-spin to low-spin.

  8. Structural and Magnetic Behavior of a Quasi-1D Antiferromagnetic Chain Compound Cu(NCS)(2)(PYZ)

    SciTech Connect

    Bordallo, H. N.; Chapon, L. C.; Manson, Jamie L; Qualls, J. S.; Hall, D.; Argyriou, D. N.

    2003-01-01

    Synchrotron X-ray diffraction (XRD) and neutron powder diffraction (NPD) were used to determine the structure of Cu(NCS){sub 2}(pyz) (pyz=pyrazine=C{sub 4}N{sub 2}H{sub 4}), which consists of a stacking of Cu-pyz-Cu chains. While NPD measurements showed no evidence of long-range magnetic ordering, the temperature dependence of the magnetic susceptibility and magnetization suggests that the system can be adequately described on the local scale as a spin-1/2 antiferromagnet (AFM) chain with an intrachain exchange interaction J/k{sub B} = -8 K ({approx}0.7 meV). Comparison of isothermal magnetization data acquired up to 30 T at 1.6 K to a linear chain model shows excellent agreement, making this material a nearly ideal example of an isotropic Heisenberg AFM chain.

  9. Calculated impact of ferromagnetic substrate on the spin crossover in a Fe(1 ,10 -phenanthroline) 2(NCS) 2 molecule

    NASA Astrophysics Data System (ADS)

    Gueddida, S.; Alouani, M.

    2016-05-01

    Spin crossover in the Fe(1 ,10 -phenanthroline) 2(NCS) 2 (Fephen) molecule adsorbed on ferromagnetic cobalt (001) and (111) surfaces as well as a gold (001) surface has been studied using the projector augmented wave method in conjunction with the density functional theory within the generalized gradient approximation, including a Hubbard interaction U at the iron site and a van der Waals weak interaction between the molecule and the surface. It is shown that the energy difference between the high-spin (HS) and the low-spin (LS) states and the energy barrier of Fephen/Co(111) are significantly reduced compared to those of the adsorbed molecule on Cu(001) and Au(001). This makes the switching of the molecule from the HS to the LS state much easier than when the molecule is adsorbed on a copper or gold substrate. It is also shown that an indirect exchange mechanism is responsible for the ferromagnetic coupling between the Fe center of Fephen and the cobalt substrate and that, in the LS state, the Fephen/Co interface remains magnetically active due to small induced magnetic moments in the NCS group and iron center. This magnetic coupling between the molecule and the substrate decreases in an oscillatory fashion as a function of the number of copper layers inserted between the molecule and the cobalt substrate, in a manner similar to that of the interlayer magnetic exchange coupling. Finally, scanning tunneling microscopy images at the Fermi level show that the separation between the phen lobes is larger in the HS state than in the LS state and the work functions of cobalt, gold, and copper substrates are strongly reduced upon adsorption of the Fephen molecule.

  10. Sense and specificity in neuronal calcium signalling☆

    PubMed Central

    Burgoyne, Robert D.; Haynes, Lee P.

    2015-01-01

    Changes in the intracellular free calcium concentration ([Ca2 +]i) in neurons regulate many and varied aspects of neuronal function over time scales from microseconds to days. The mystery is how a single signalling ion can lead to such diverse and specific changes in cell function. This is partly due to aspects of the Ca2 + signal itself, including its magnitude, duration, localisation and persistent or oscillatory nature. The transduction of the Ca2 + signal requires Ca2 + binding to various Ca2 + sensor proteins. The different properties of these sensors are important for differential signal processing and determine the physiological specificity of Ca2 + signalling pathways. A major factor underlying the specific roles of particular Ca2 + sensor proteins is the nature of their interaction with target proteins and how this mediates unique patterns of regulation. We review here recent progress from structural analyses and from functional analyses in model organisms that have begun to reveal the rules that underlie Ca2 + sensor protein specificity for target interaction. We discuss three case studies exemplifying different aspects of Ca2 + sensor/target interaction. This article is part of a special issue titled the 13th European Symposium on Calcium. PMID:25447549

  11. Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy)2(PS)2 complexes, PS = CN, NCS and N3

    NASA Astrophysics Data System (ADS)

    Compton, Ryan; Gerardi, Helen K.; Weidinger, Daniel; Brown, Douglas J.; Dressick, Walter J.; Heilweil, Edwin J.; Owrutsky, Jeffrey C.

    2013-08-01

    Static and transient infrared spectroscopy were used to investigate cis-Ru(bpy)2(N3)2 (bpy = 2,2‧-bipyridine), cis-Ru(bpy)2(NCS)2, and cis-Ru(bpy)2(CN)2 in solution. The NC stretching IR band for cis-Ru(bpy)2(NCS)2 appears at higher frequency (∼2106 cm-1 in DMSO) than for the free NCS- anion while the IR bands for the azide and cyanide complexes are closer to those of the respective free anions. The vibrational energy relaxation (VER) lifetime for the azide complex is found to be much shorter (∼5 ps) than for either the NCS or CN species (both ∼70 ps in DMSO) and the lifetimes resemble those for each corresponding free anion in solution. However, for cis-Ru(bpy)2(N3)2, it is determined that the transition frequency depends more on the solvent than the VER lifetime implying that intramolecular vibrational relaxation is predominant over solvent energy-extracting interactions. These results are compared to the behavior of other related metal complexes in solution.

  12. From Too Much Freedom to Too Much Restriction: The Case of Teacher Autonomy from National Curriculum Statement (NCS) to Curriculum and Assessment Statement (CAPS)

    ERIC Educational Resources Information Center

    Ramatlapana, K.; Makonye, J. P.

    2012-01-01

    The major curricula revisions in South Africa in the last two decades or so have changed the curriculum landscape. These revisions are meant to effect among other issues, the socio-economic development for all through quality education. The latest curricula transition from National Curriculum Statement (NCS) to Curriculum and Assessment Policy…

  13. Two-bit memory and quantized storage phenomenon in conventional MOS structures with double-stacked Pt-NCs in an HfAlO matrix.

    PubMed

    Zhou, Guangdong; Wu, Bo; Liu, Xiaoqin; Li, Ping; Zhang, Shuangju; Sun, Bai; Zhou, Ankun

    2016-03-01

    A two-bit memory and quantized storage phenomenon are observed at room temperature for a device based on the traditional MOS structure with double-stacked Pt-nanocrystals (Pt-NCs). A 2.68 and 1.72 V flat band voltage shift (memory window) has been obtained when applying a ±7 V programming/erasing voltage to the structures with double-stacked Pt-NCs. The memory windows of 2.40 and 1.44 V can be retained after stress for 10(5) seconds, which correspond to 89.55% and 83.72% stored charges reserved. The quantized charge storage phenomenon characterized by current-voltage (J-V) hysteresis curves was detected at room temperature. The shrinkage of the memory window results from the decreasing tunneling probability, which strongly depends on the number of stacks. The traps, de-traps and quantum confinement effects of Pt-NCs may contribute to the improvement of dielectric characteristics and the two-bit memory behavior. The multi-bit memory and quantized storage behavior observed in the Pt-NCs stacks structure at room temperature might provide a feasible method for realizing the multi-bit storage in non-volatile flash memory devices. PMID:26864686

  14. Lifetime Prevalence of Mental Disorders in U.S. Adolescents: Results from the National Comorbidity Survey Replication-Adolescent Supplement (NCS-A)

    ERIC Educational Resources Information Center

    Merikangas, Kathleen Ries; He, Jian-ping; Burstein, Marcy; Swanson, Sonja A.; Avenevoli, Shelli; Cui, Lihong; Benjet, Corina; Georgiades, Katholiki; Swendsen, Joel

    2010-01-01

    Objective: To present estimates of the lifetime prevalence of "DSM-IV" mental disorders with and without severe impairment, their comorbidity across broad classes of disorder, and their sociodemographic correlates. Method: The National Comorbidity Survey-Adolescent Supplement NCS-A is a nationally representative face-to-face survey of 10,123…

  15. Synthesis and structure of R{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (R = Rb or Cs)

    SciTech Connect

    Serezhkin, V. N.; Peresypkina, E. V.; Grigor’eva, V. A.; Virovets, A. V.; Serezhkina, L. B.

    2015-01-15

    Crystals Rb{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (I) and Cs{sub 2}[UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}] (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals I are monoclinic, with the following parameters: a = 12.2118(5) Å, b = 10.2545(3) Å, c = 11.8754(4) Å, β = 110.287(1)°, sp. gr. C2/c, Z = 4, and R = 0.0523. Crystals II are orthorhombic, with a = 13.7309(3) Å, b = 10.5749(2) Å, c = 10.1891(2) Å, sp. gr. Pnma, Z = 4, and R = 0.0411. The basic structural units of crystals I and II are one-core complexes [UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}]{sup 2−}, which belong to the crystallochemical group cis-AB{sub 2}{sup 01}M{sub 2}{sup 1} (A = UO{sub 2}{sup 2+}, B{sup 01} = NO{sub 3}{sup −}, M{sup 1} = NCS{sup −}), which are combined into a framework via electrostatic interactions with ions of alkaline metals R (R = Rb or Cs). The structural features of crystals I and II, which condition the formation of [UO{sub 2}(NO{sub 3}){sub 2}(NCS){sub 2}]{sup 2−} complexes with a cis rather than a trans position of isothiocyanate ions in the coordination sphere of uranyl ions, are discussed.

  16. Calcium Stores in Vertebrate Photoreceptors

    PubMed Central

    Križaj, David

    2012-01-01

    This review lays out the emerging evidence for the fundamental role of Ca2+ stores and store-operated channels in the Ca2+ homeostasis of rods and cones. Calcium-induced calcium release (CICR) is a major contributor to steady-state and light-evoked photoreceptor Ca2+ homeostasis in the darkness whereas store-operated Ca2+ channels play a more significant role under sustained illumination conditions. The homeostatic response includes dynamic interactions between the plasma membrane, endoplasmic reticulum (ER), mitochondria and/or outer segment disk organelles which dynamically sequester, accumulate and release Ca2+. Coordinated activation of SERCA transporters, ryanodine receptors (RyR), inositol triphosphate receptors (IP3Rs) and TRPC channels amplifies cytosolic voltage-operated signals but also provides a memory trace of previous exposures to light. Store-operated channels, activated by the STIM1 sensor, prevent pathological decrease in [Ca2+]i mediated by excessive activation of PMCA transporters in saturating light. CICR and SOCE may also modulate the transmission of afferent and efferent signals in the outer retina. Thus, Ca2+ stores provide additional complexity, adaptability, tuneability and speed to photoreceptor signaling. PMID:22453974

  17. Lead in calcium supplements.

    PubMed

    Scelfo, G M; Flegal, A R

    2000-04-01

    Intercalibrated measurements of lead in calcium supplements indicate the importance of rigorous analytical techniques to accurately quantify contaminant exposures in complex matrices. Without such techniques, measurements of lead concentrations in calcium supplements may be either erroneously low, by as much as 50%, or below the detection limit needed for new public health criteria. In this study, we determined the lead content of 136 brands of supplements that were purchased in 1996. The calcium in the products was derived from natural sources (bonemeal, dolomite, or oyster shell) or was synthesized and/or refined (chelated and nonchelated calcium). The dried products were acid digested and analyzed for lead by high resolution-inductively coupled plasma-mass spectrometry. The method's limit of quantitation averaged 0.06 microg/g, with a coefficient of variation of 1.7% and a 90-100% lead recovery of a bonemeal standard reference material. Two-thirds of those calcium supplements failed to meet the 1999 California criteria for acceptable lead levels (1.5 microg/daily dose of calcium) in consumer products. The nonchelated synthesized and/or refined calcium products, specifically antacids and infant formulas, had the lowest lead concentrations, ranging from nondetectable to 2.9 microg Pb/g calcium, and had the largest proportion of brands meeting the new criteria (85% of the antacids and 100% of the infant formulas). PMID:10753088

  18. Lead in calcium supplements.

    PubMed Central

    Scelfo, G M; Flegal, A R

    2000-01-01

    Intercalibrated measurements of lead in calcium supplements indicate the importance of rigorous analytical techniques to accurately quantify contaminant exposures in complex matrices. Without such techniques, measurements of lead concentrations in calcium supplements may be either erroneously low, by as much as 50%, or below the detection limit needed for new public health criteria. In this study, we determined the lead content of 136 brands of supplements that were purchased in 1996. The calcium in the products was derived from natural sources (bonemeal, dolomite, or oyster shell) or was synthesized and/or refined (chelated and nonchelated calcium). The dried products were acid digested and analyzed for lead by high resolution-inductively coupled plasma-mass spectrometry. The method's limit of quantitation averaged 0.06 microg/g, with a coefficient of variation of 1.7% and a 90-100% lead recovery of a bonemeal standard reference material. Two-thirds of those calcium supplements failed to meet the 1999 California criteria for acceptable lead levels (1.5 microg/daily dose of calcium) in consumer products. The nonchelated synthesized and/or refined calcium products, specifically antacids and infant formulas, had the lowest lead concentrations, ranging from nondetectable to 2.9 microg Pb/g calcium, and had the largest proportion of brands meeting the new criteria (85% of the antacids and 100% of the infant formulas). Images Figure 1 Figure 2 PMID:10753088

  19. Spin crossover transition of Fe(phen)2(NCS)2: periodic dispersion-corrected density-functional study.

    PubMed

    Bučko, Tomáš; Hafner, Jürgen; Lebègue, Sébastien; Ángyán, János G

    2012-04-28

    Periodic dispersion corrected DFT calculations have been performed to study the spin-crossover transition of Fe(phen)(2)(NCS)(2) in the molecular and in the crystalline state. We show that London dispersion interactions play a crucial role in the cohesion of the crystals. Based on calculations of vibrational eigenstates of the isolated molecule and of the crystalline phase in both the low- and high-spin states, the transition entropies and enthalpies have been calculated. We demonstrate that, due to the stabilization of the low-spin state by intermolecular dispersion forces, the transition enthalpy at the transition temperature is larger for the crystalline phase in comparison with an isolated molecule. The effective coordination number of the nitrogen atoms of the ligands around the iron atom has been identified as the order parameter driving the quasi-reversible low-spin to high-spin transition in the crystal. Finally, using constrained geometry relaxations at fixed values of the coordination number, we computed the energy barrier of the LS to HS transition and found it to be in a reasonable agreement with the experimental value. PMID:22415338

  20. [Intensive care therapy of space-occupying large hemispheric infarction. Summary of the NCS/DGNI guidelines].

    PubMed

    Bösel, J; Schönenberger, S; Dohmen, C; Jüttler, E; Staykov, D; Zweckberger, K; Hacke, W; Schwab, S; Torbey, M T; Huttner, H B

    2015-08-01

    Large hemispheric infarction (LHI), synonymously called malignant middle cerebral artery (MCA) infarction, is a severe neurological disease with a high mortality and morbidity. Treating physicians as well as relatives are often faced with few and low quality data when attempting to apply optimal treatment to these patients and make decisions. While current stroke treatment guidelines focus on risk factors, prevention and acute management, they include only limited recommendations concerning intensive care management of LHI. The Neurocritical Care Society (NCS) and the German Society for Neurocritical and Emergency Medicine (DGNI) organized an interdisciplinary consensus conference on intensive care management of LHI to meet this demand. European and American experts in neurology, neurocritical care, neurosurgery, neuroradiology and neuroanesthesiology were selected based on their expertise and research focus. Subgroups for several main topics elaborated a number of central clinical questions concerning this topic and evaluated the quality of the currently available data according to the grading of recommendation assessment, development and evaluation (GRADE) guideline system. Subsequently, evidence-based recommendations were compiled after weighing the advantages against the disadvantages of certain management options. This is a commented abridged version of the results of the consensus conference. PMID:26108877

  1. Mixed-state magnetoresistance in organic superconductors {kappa}{endash}(BEDT-TTF){sub 2}Cu(NCS){sub 2}

    SciTech Connect

    Zuo, F.; Schlueter, J.A.; Kelly, M.E.; Williams, J.M.

    1996-11-01

    We report transport measurements with field and current parallel to the {ital a} axis (perpendicular to the conducting plane) in the organic superconductor {kappa}{endash}(BEDT-TTF){sub 2}Cu(NCS){sub 2}. The magnetoresistance displays a peak effect as a function of field and temperature with the peak fields increasing linearly with decreasing temperatures. The peak resistance is found to be greater than the normal-state value extrapolated from both high- and low-field measurements. The results are in sharp contrast to the conventional dissipation mechanisms in the mixed state for anisotropic superconductors, as in the case of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}. We propose a phenomenological model that the peak in the magnetoresistance is caused by a scattering mechanism due to a strong coupling to the underlying crystal lattice of fluctuating vortices (vortex polarons). The model can semiquantitatively fit the data. {copyright} {ital 1996 The American Physical Society.}

  2. Decoding of calcium signal through calmodulin: calmodulin-binding proteins in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many abiotic and biotic stimuli such as heat, cold, drought, salt, light, wind, touch, wounding, symbionts and pathogens as well as growth, developmental and hormonal cues can quickly induce cytosolic calcium increases. Calmodulin, the most thoroughly studied calcium sensor, mediates interpretation...

  3. Comparative effects of oral aromatic and branched-chain amino acids on urine calcium and excretion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aromatic amino acids (AAAs) bind to the calcium sensor receptor (CaR) but branched-chain amino acids (B-CAAs) do not; by binding to this receptor, AAAs have an increased potential to affect calcium homeostasis. This study was conducted to determine and compare the effects of AAAs and B-CAAs on calci...

  4. [Calcium and health].

    PubMed

    Ortega Anta, Rosa M; Jiménez Ortega, Ana I; López-Sobaler, Ana M

    2015-01-01

    An adequate intake of calcium is only not limited to avoid the risk of osteoporosis and its benefits in longterm bone health, but also it has been linked to protection against various major diseases, such as hypertension, cancer, kidney stones, insulin resistance, diabetes... and several investigations suggest its importance in preventing and controlling obesity. Studies conducted in Spanish representative samples show that a high percentage of adults and children (> 75%) don't achieve the recommended intake of calcium. Moreover, are growing trends among the population suggesting that calcium intake and dairy consumption (main food source of the mineral) are high, and even excessive, in many individuals. This misconception results in that the calcium intake is increasingly far from the recommended one. The maximum tolerable intake of the mineral is fixed at 2.500 mg/day, but this intake is unusual, and it's more disturbing and frequent, to find intakes below the recommended calcium intakes (1.000 and 1.200 mg/day in adults, men and women, respectively). Data from different studies highlight the risk of an inadequate calcium intake and the damages that may affect the health in a long term. It is not about transmitting indiscriminate guidelines in order to increase the intake of calcium / dairy, but the recommended intakes must be met to achieve both the nutritional and health benefits. Also activities for demystification of misconceptions are need, increasingly frequent, that may impair health population. PMID:25862324

  5. GCY-8, PDE-2, and NCS-1 are critical elements of the cGMP-dependent thermotransduction cascade in the AFD neurons responsible for C. elegans thermotaxis

    PubMed Central

    Wang, Dong; O’Halloran, Damien

    2013-01-01

    Certain thermoreceptor neurons are sensitive to tiny thermal fluctuations (0.01°C or less) and maintain their sensitivity across a wide range of ambient temperatures through a process of adaptation, but understanding of the biochemical basis for this performance is rudimentary. Prior studies of the AFD thermoreceptor in Caenorhabditis elegans revealed a signaling cascade that depends on a trio of receptor guanylate cyclases (rGCs), GCY-8, GCY-18, and GCY-23, and gives rise to warming-activated thermoreceptor currents (ThRCs) carried by cyclic GMP–gated ion channels. The threshold for ThRC activation adapts to the ambient temperature through an unknown calcium-dependent process. Here, we use in vivo whole-cell patch-clamp recording from AFD to show that loss of GCY-8, but not of GCY-18 or GCY-23, reduces or eliminates ThRCs, identifying this rGC as a crucial signaling element. To learn more about thermotransduction and adaptation, we used behavioral screens and analysis of gene expression patterns to identify phosphodiesterases (PDEs) likely to contribute to thermotransduction. Deleting PDE-2 decouples the threshold for ThRC activation from ambient temperature, altering adaptation. We provide evidence that the conserved neuronal calcium sensor 1 protein also regulates the threshold for ThRC activation and propose a signaling network to account for ThRC activation and adaptation. Because PDEs play essential roles in diverse biological processes, including vertebrate phototransduction and olfaction, and regulation of smooth muscle contractility and cardiovascular function, this study has broad implications for understanding how extraordinary sensitivity and dynamic range is achieved in cyclic nucleotide–based signaling networks. PMID:24081984

  6. Handling packet dropouts and random delays for unstable delayed processes in NCS by optimal tuning of PIλDμ controllers with evolutionary algorithms.

    PubMed

    Pan, Indranil; Das, Saptarshi; Gupta, Amitava

    2011-10-01

    The issues of stochastically varying network delays and packet dropouts in Networked Control System (NCS) applications have been simultaneously addressed by time domain optimal tuning of fractional order (FO) PID controllers. Different variants of evolutionary algorithms are used for the tuning process and their performances are compared. Also the effectiveness of the fractional order PI(λ)D(μ) controllers over their integer order counterparts is looked into. Two standard test bench plants with time delay and unstable poles which are encountered in process control applications are tuned with the proposed method to establish the validity of the tuning methodology. The proposed tuning methodology is independent of the specific choice of plant and is also applicable for less complicated systems. Thus it is useful in a wide variety of scenarios. The paper also shows the superiority of FOPID controllers over their conventional PID counterparts for NCS applications. PMID:21621208

  7. Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

    NASA Astrophysics Data System (ADS)

    Nehm, F.; Müller-Meskamp, L.; Klumbies, H.; Leo, K.

    2015-12-01

    A major failure mechanism is identified in electrical calcium corrosion tests for quality assessment of high-end application moisture barriers. Accelerated calcium corrosion is found at the calcium/electrode junction, leading to an electrical bottleneck. This causes test failure not related to overall calcium loss. The likely cause is a difference in electrochemical potential between the aluminum electrodes and the calcium sensor, resulting in a corrosion element. As a solution, a thin, full-area copper layer is introduced below the calcium, shifting the corrosion element to the calcium/copper junction and inhibiting bottleneck degradation. Using the copper layer improves the level of sensitivity for the water vapor transmission rate (WVTR) by over one order of magnitude. Thin-film encapsulated samples with 20 nm of atomic layer deposited alumina barriers this way exhibit WVTRs of 6 × 10-5 g(H2O)/m2/d at 38 °C, 90% relative humidity.

  8. Calcium, channels, intracellular signaling and autoimmunity.

    PubMed

    Izquierdo, Jorge-Hernán; Bonilla-Abadía, Fabio; Cañas, Carlos A; Tobón, Gabriel J

    2014-01-01

    Calcium (Ca²⁺) is an important cation able to function as a second messenger in different cells of the immune system, particularly in B and T lymphocytes, macrophages and mastocytes, among others. Recent discoveries related to the entry of Ca²⁺ through the store-operated calcium entry (SOCE) has opened a new investigation area about the cell destiny regulated by Ca²⁺ especially in B and T lymphocytes. SOCE acts through calcium-release-activated calcium (CRAC) channels. The function of CRAC depends of two recently discovered regulators: the Ca²⁺ sensor in the endoplasmic reticulum or stromal interaction molecule (STIM-1) and one subunit of CRAC channels called Orai1. This review focuses on the role of Ca²⁺ signals in B and T lymphocytes functions, the signalling pathways leading to Ca²⁺ influx, and the relationship between Ca²⁺ signals and autoimmune diseases. PMID:24001934

  9. Molecular Basis of Substrate Promiscuity for the SAM-Dependent O-Methyltransferase NcsB1, Involved in the Biosynthesis of the Enediyne Antitumor Antibiotic Neocarzinostatin

    SciTech Connect

    Cooke, H.; Guenther, E; Luo, Y; Shen, B; Bruner, S

    2009-01-01

    The small molecule component of chromoprotein enediyne antitumor antibiotics is biosynthesized through a convergent route, incorporating amino acid, polyketide, and carbohydrate building blocks around a central enediyne hydrocarbon core. The naphthoic acid moiety of the enediyne neocarzinostatin plays key roles in the biological activity of the natural product by interacting with both the carrier protein and duplex DNA at the site of action. We have previously described the in vitro characterization of an S-adenosylmethionine-dependent O-methyltransferase (NcsB1) in the neocarzinostatin biosynthetic pathway [Luo, Y., Lin, S., Zhang, J., Cooke, H. A., Bruner, S. D., and Shen, B. (2008) J. Biol. Chem. 283, 14694-14702]. Here we provide a structural basis for NcsB1 activity, illustrating that the enzyme shares an overall architecture with a large family of S-adenosylmethionine-dependent proteins. In addition, NcsB1 represents the first enzyme to be structurally characterized in the biosynthetic pathway of neocarzinostatin. By cocrystallizing the enzyme with various combinations of the cofactor and substrate analogues, details of the active site structure have been established. Changes in subdomain orientation were observed via comparison of structures in the presence and absence of substrate, suggesting that reorientation of the enzyme is involved in binding of the substrate. In addition, residues important for substrate discrimination were predicted and probed through site-directed mutagenesis and in vitro biochemical characterization.

  10. Locking-to-unlocking system is an efficient strategy to design DNA/silver nanoclusters (AgNCs) probe for human miRNAs

    PubMed Central

    Shah, Pratik; Choi, Suk Won; Kim, Ho-jin; Cho, Seok Keun; Bhang, Yong-Joo; Ryu, Moon Young; Thulstrup, Peter Waaben; Bjerrum, Morten Jannik; Yang, Seong Wook

    2016-01-01

    MicroRNAs (miRNAs), small non-coding RNA molecules, are important biomarkers for research and medical purposes. Here, we describe the development of a fast and simple method using highly fluorescent oligonucleotide-silver nanocluster probes (DNA/AgNCs) to efficiently detect specific miRNAs. Due to the great sequence diversity of miRNAs in humans and other organisms, a uniform strategy for miRNA detection is attractive. The concept presented is an oligonucleotide-based locking-to-unlocking system that can be endowed with miRNA complementarity while maintaining the same secondary structure. The locking-to-unlocking system is based on fold-back anchored DNA templates that consist of a cytosine-rich loop for AgNCs stabilization, an miRNA recognition site and an overlap region for hairpin stabilization. When an miRNA is recognized, fluorescence in the visible region is specifically extinguished in a concentration-dependent manner. Here, the exact composition of the fold-back anchor for the locking-to-unlocking system has been systematically optimized, balancing propensity for loop-structure formation, encapsulation of emissive AgNCs and target sensitivity. It is demonstrated that the applied strategy successfully can detect a number of cancer related miRNAs in RNA extracts from human cancer cell lines. PMID:26681688

  11. Locking-to-unlocking system is an efficient strategy to design DNA/silver nanoclusters (AgNCs) probe for human miRNAs.

    PubMed

    Shah, Pratik; Choi, Suk Won; Kim, Ho-Jin; Cho, Seok Keun; Bhang, Yong-Joo; Ryu, Moon Young; Thulstrup, Peter Waaben; Bjerrum, Morten Jannik; Yang, Seong Wook

    2016-04-01

    MicroRNAs (miRNAs), small non-coding RNA molecules, are important biomarkers for research and medical purposes. Here, we describe the development of a fast and simple method using highly fluorescent oligonucleotide-silver nanocluster probes (DNA/AgNCs) to efficiently detect specific miRNAs. Due to the great sequence diversity of miRNAs in humans and other organisms, a uniform strategy for miRNA detection is attractive. The concept presented is an oligonucleotide-based locking-to-unlocking system that can be endowed with miRNA complementarity while maintaining the same secondary structure. The locking-to-unlocking system is based on fold-back anchored DNA templates that consist of a cytosine-rich loop for AgNCs stabilization, an miRNA recognition site and an overlap region for hairpin stabilization. When an miRNA is recognized, fluorescence in the visible region is specifically extinguished in a concentration-dependent manner. Here, the exact composition of the fold-back anchor for the locking-to-unlocking system has been systematically optimized, balancing propensity for loop-structure formation, encapsulation of emissive AgNCs and target sensitivity. It is demonstrated that the applied strategy successfully can detect a number of cancer related miRNAs in RNA extracts from human cancer cell lines. PMID:26681688

  12. Molecular basis of substrate promiscuity for the SAM-dependent O-methyltransferase NcsB1, involved in the biosynthesis of the enediyne antitumor antibiotic neocarzinostatin.

    PubMed

    Cooke, Heather A; Guenther, Elizabeth L; Luo, Yinggang; Shen, Ben; Bruner, Steven D

    2009-10-13

    The small molecule component of chromoprotein enediyne antitumor antibiotics is biosynthesized through a convergent route, incorporating amino acid, polyketide, and carbohydrate building blocks around a central enediyne hydrocarbon core. The naphthoic acid moiety of the enediyne neocarzinostatin plays key roles in the biological activity of the natural product by interacting with both the carrier protein and duplex DNA at the site of action. We have previously described the in vitro characterization of an S-adenosylmethionine-dependent O-methyltransferase (NcsB1) in the neocarzinostatin biosynthetic pathway [Luo, Y., Lin, S., Zhang, J., Cooke, H. A., Bruner, S. D., and Shen, B. (2008) J. Biol. Chem. 283, 14694-14702]. Here we provide a structural basis for NcsB1 activity, illustrating that the enzyme shares an overall architecture with a large family of S-adenosylmethionine-dependent proteins. In addition, NcsB1 represents the first enzyme to be structurally characterized in the biosynthetic pathway of neocarzinostatin. By cocrystallizing the enzyme with various combinations of the cofactor and substrate analogues, details of the active site structure have been established. Changes in subdomain orientation were observed via comparison of structures in the presence and absence of substrate, suggesting that reorientation of the enzyme is involved in binding of the substrate. In addition, residues important for substrate discrimination were predicted and probed through site-directed mutagenesis and in vitro biochemical characterization. PMID:19702337

  13. Calcium in diet

    MedlinePlus

    ... level based on scientific research evidence. Adequate Intake (AI): This level is established when there is not ... enough calcium from the foods they eat. Infants (AI) 0 to 6 months: 200 milligrams per day ( ...

  14. Get Enough Calcium

    MedlinePlus

    ... Previous section Overview 2 of 4 sections Take Action! Take Action: Calcium Sources Protect your bones – get plenty of ... Foods and Vitamins 3 of 4 sections Take Action: Vitamin D Get enough vitamin D. Vitamin D ...

  15. Stoichiometry of Calcium Medicines

    ERIC Educational Resources Information Center

    Pinto, Gabriel

    2005-01-01

    The topic of calcium supplement and its effects on human lives is presented in the way of questions to the students. It enables the students to realize the relevance of chemistry outside the classroom surrounding.

  16. Calcium pyrophosphate arthritis

    MedlinePlus

    ... that can cause attacks of arthritis. Like with gout, crystals form in the joints. But in calcium ... pyrophosphate arthritis can be misdiagnosed as: Gouty arthritis (gout) Osteoarthritis Rheumatoid arthritis

  17. Risk factors for twelve-month suicide attempts in the National Comorbidity Survey Replication (NCS-R)

    PubMed Central

    Borges, Guilherme; Angst, Jules; Nock, Matthew K.; Ruscio, Ayelet Meron; Walters, Ellen E.; Kessler, Ronald C.

    2007-01-01

    BACKGROUND Clinical judgments about the likelihood of suicide attempt would be aided by an index of risk factors that could be quickly assessed in diverse settings. We sought to develop such a risk index for 12-month suicide attempts among suicide ideators. METHOD The National Comorbidity Survey Replication (NCS-R), a household survey of adults ages 18+, assessed 12-month occurrence of suicide ideation, plans, and attempts in a subsample of 5692 respondents. Retrospectively assessed correlates include history of prior suicidality, socio-demographics, parental psychopathology, and 12-month DSM-IV disorders. RESULTS Twelve-month prevalence estimates of suicide ideation, plans, and attempts are 2.6%, 0.7%, and 0.4%. Although ideators with a plan are more likely to make an attempt (31.9%) than those without a plan (9.6%), 43% of attempts were described as unplanned. History of prior attempts is the strongest correlate of 12-month attempts. Other significant correlates include shorter duration of ideation, presence of a suicide plan, and several socio-demographic and parental psychopathology variables. Twelve-month disorders are not powerful correlates. A four-category summary index of correlates is strongly related to attempts among ideators (AUC = .88). The distribution (conditional probability of attempt) of the risk index is 19.0% very low (0.0%), 51.1% low (3.5%), 16.2% intermediate (21.3%), and 13.7% high (78.1%). Two-thirds (67.1%) of attempts were made by ideators in the high risk category. CONCLUSIONS A short, preliminary risk index based on retrospectively reported responses to fully structured questions is strongly correlated with 12-month suicide attempts among ideators, with a high concentration of attempts among high-risk ideators. PMID:16938149

  18. Pathological Gambling, Problem Gambling and Sleep Complaints: An Analysis of the National Comorbidity Survey: Replication (NCS-R)

    PubMed Central

    Siani, Aaron; Rosenthal, Richard J.; Fong, Timothy W.

    2012-01-01

    The purpose of this study is to investigate the relationship between sleep disturbances and gambling behavior. Data from the National Comorbidity Survey—Replication (NCS-R) was used to examine the relationship between three specific sleep complaints (difficulty initiating sleep [DIS], difficulty maintaining sleep [DMS], and early morning awakening [EMA]) and gambling behavior. Bivariate logistic regression models were used to control for potentially confounding psychiatric disorders and age. Almost half of respondents with problem gambling behavior (45.9%) and two thirds (67.7%) of respondents with pathological gambling behavior reported at least one sleep compliant. Compared to respondents with no gambling pathology, respondents with pathological gambling were significantly more likely to report at least one sleep complaint (Adjusted Odds Ratio [AOR] = 3.444, 95% CI = 1.538–7.713), to report all sleep complaints (AOR = 3.449, 95% CI = 1.503–7.914), and to report any individual complaint (DIS: OR = 2.300, 95% CI = 1.069–4.946; DMS: AOR = 4.604, 95% CI = 2.093–10.129; EMA: AOR = 3.968, 95% CI = 1.856–8.481). The relationship between problem gambling and sleep complaints were more modest (any sleep complaint: AOR = 1.794, 95% CI = 1.142–2.818; all three sleep complaints: AOR = 2.144, 95% CI = 1.169–3.931; DIS: AOR = 1.961, 95% CI = 1.204–3.194; DMS: AOR = 1.551, 95% CI = 0.951–2.529; EMA: AOR = 1.796, 95% CI = 1.099–2.935). Given the individual and societal ramifications linked with the presence of sleep problems, this study presents another health-related repercussion associated with gambling pathology rarely discussed in the literature. PMID:22396174

  19. Synthesis, characterization and crystal structure of a 1D thiocyanato bridged [Cu(en)2Zn(NCS)4]ṡH2O. Comparison of the three structures with the same [Cu(en)2Zn(NCS)4] unit - different in structural terms

    NASA Astrophysics Data System (ADS)

    Wrzeszcz, Grzegorz; Muzioł, Tadeusz M.; Tereba, Natalia

    2015-03-01

    In this paper we report the synthesis method and the structure of a one-dimensional thiocyanato bridged heterometallic compound, [Cu(en)2Zn(NCS)4]ṡH2O (1). Moreover, we compare the structure of (1) with the previously described structures of [Cu(en)2Zn(NCS)4]ṡ0.5H2O (2) and [Cu(en)2Zn(NCS)4]ṡCH3CN (3) Pryma et al. (2003) [7]. The compound (1) has been characterized by thermal decomposition, IR, Vis and EPR spectra, and magnetic studies. Structure has been determined by X-ray analysis. Described coordination polymer crystallizes in the orthorhombic Cmcm space group with a = 12.414(2), b = 10.3276(14), c = 14.967(2) Å, α = β = γ = 90°, V = 1918.8(5) Å3 and Z = 4. Each distorted tetrahedral zinc(II) centre (with N-bonded NCS-) links two tetragonally distorted octahedral copper(II) centres by two end-to-end thiocyanato bridges and vice versa forming a zigzag type of CuZn chain. The structures of (1), (2) and (3) differ in crystallographic system, space group and/or CuZn chain type as well as in details. Variable temperature magnetic susceptibility measurements show very weak antiferromagnetic interactions between the paramagnetic copper(II) ions for compound (1).

  20. NCS TECHNOLOGY WORKSHOP & REPORT

    EPA Science Inventory

    Innovative Technologies for Remote Collection of Data

  21. May 12-14, 2003
  22. Hyatt Harborside Hotel
  23. Boston, MA
  24. This meeting was held in conjunction with the National Children's ...

  1. Calcium decorated and doped phosphorene for gas adsorption

    NASA Astrophysics Data System (ADS)

    Lalitha, Murugan; Nataraj, Yuvarani; Lakshmipathi, Senthilkumar

    2016-07-01

    In this paper, we present the results from first-principles study based on the electronic structure and adsorption characteristics of CH4, CO2, H2 and NH3 adsorbed on Ca decorated/doped phosphorene. Our study finds that phosphorene exhibits n-type behaviour on decorating calcium, and p-type on doping calcium. Gas molecules are physisorbed on both pristine and calcium-mediated phosphorene, visible through their lower binding energy and charge transfer values. Ca decorated phosphorene is suitable for hydrogen storage due to its higher binding energy for H2. Ca doped structures shows increased binding affinity towards CH4 and NH3 in zigzag1 direction and armchair directions respectively. The extracts of our study implies that Ca doped phosphorene possess increased binding affinity towards gas molecules, and the results are highly helpful for gas adsorption and to design gas sensors based on calcium doped or decorated phosphorene.

  2. Current sensor

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2007-01-16

    A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

  3. Modelling of calcium phosphates

    NASA Astrophysics Data System (ADS)

    Calderin Hidalgo, Lazaro Juan

    This work is a contribution to a large scale joint experimental and theoretical effort to understand the biological properties of silicon doped calcium phosphates undertaken by Queen's University and Millenium Biologix Corp. We have modeled calcium phosphates and silicon doped calcium phosphates in close relation to experiment in order to study possible location of silicon in the lattice. Density functional theory has been used to study the structural and dynamical properties of small systems of calcium phosphates to gain preliminary information on phosphates and the performance of the theoretical methods. The same methods were used to investigate structural and electronic properties of larger scale calcium phosphate systems, while a classical shell model was developed to investigate the dynamical properties of such large and complex systems. In the context of the shell model a method was devised to calculate the dynamical matrix corrected for the long range Coulomb interaction in the long wave length limit. It was necessary also to develop a theoretical expression for the dielectric function in the context of the shell model. Infrared spectra and thermal parameters were calculated based on these methods. We also propose some directions for future research.

  4. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    ERIC Educational Resources Information Center

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

    The gravimetric determination of calcium as calcium carbonate is described. This experiment is suitable for undergraduate quantitative analysis laboratories. It is less expensive than determination of chloride as silver chloride. (BB)

  5. Calcium and olfactory transduction.

    PubMed

    Winegar, B D; Rosick, E R; Schafer, R

    1988-01-01

    1. Inorganic cations, organic calcium antagonists, and calmodulin antagonists were applied to olfactory epithelia of frogs (Rana pipiens) while recording electroolfactogram (EOG) responses. 2. Inorganic cations inhibited EOGs in a rank order, reflecting their calcium channel blocking potency: La3+ greater than Zn2+ greater than Cd2+ greater than Al3+ greater than Ca2+ greater than Sr2+ greater than Co2+ greater than Ba2+ greater than Mg2+. Barium ion significantly enhanced EOGs immediately following application. 3. Diltiazem and verapamil produced dose-dependent EOG inhibition. 4. Calmodulin antagonists inhibited EOGs without correlation to their anti-calmodulin potency. PMID:2904344

  6. Calcium metabolism in microgravity.

    PubMed

    Heer, M; Kamps, N; Biener, C; Korr, C; Boerger, A; Zittermann, A; Stehle, P; Drummer, C

    1999-09-01

    Unloading of weight bearing bones as induced by microgravity or immobilization has significant impacts on the calcium and bone metabolism and is the most likely cause for space osteoporosis. During a 4.5 to 6 month stay in space most of the astronauts develop a reduction in bone mineral density in spine, femoral neck, trochanter, and pelvis of 1%-1.6% measured by Dual Energy X-ray Absorption (DEXA). Dependent on the mission length and the individual turnover rates of the astronauts it can even reach individual losses of up to 14% in the femoral neck. Osteoporosis itself is defined as the deterioration of bone tissue leading to enhanced bone fragility and to a consequent increase in fracture risk. Thinking of long-term missions to Mars or interplanetary missions for years, space osteoporosis is one of the major concerns for manned spaceflight. However, decrease in bone density can be initiated differently. It either can be caused by increases in bone formation and bone resorption resulting in a net bone loss, as obtained in fast looser postmenopausal osteoporosis. On the other hand decrease in bone formation and increase in bone resorption also leads to bone losses as obtained in slow looser postmenopausal osteoporosis or in Anorexia Nervosa patients. Biomarkers of bone turnover measured during several missions indicated that the pattern of space osteoporosis is very similar to the pattern of Anorexia Nervosa patients or slow looser postmenopausal osteoporosis. However, beside unloading, other risk factors for space osteoporosis exist such as stress, nutrition, fluid shifts, dehydration and bone perfusion. Especially nutritional factors may contribute considerably to the development of osteoporosis. From earthbound studies it is known that calcium supplementation in women and men can prevent bone loss of 1% bone per year. Based on these results we studied the calcium intake during several European missions and performed an experiment during the German MIR 97 mission

  7. Structural aspects of calcium-release activated calcium channel function

    PubMed Central

    Stathopulos, Peter B; Ikura, Mitsuhiko

    2013-01-01

    Store-operated calcium (Ca2+) entry is the process by which molecules located on the endo/sarcoplasmic reticulum (ER/SR) respond to decreased luminal Ca2+ levels by signaling Ca2+ release activated Ca2+ channels (CRAC) channels to open on the plasma membrane (PM). This activation of PM CRAC channels provides a sustained cytosolic Ca2+ elevation associated with myriad physiological processes. The identities of the molecules which mediate SOCE include stromal interaction molecules (STIMs), functioning as the ER/SR luminal Ca2+ sensors, and Orai proteins, forming the PM CRAC channels. This review examines the current available high-resolution structural information on these CRAC molecular components with particular focus on the solution structures of the luminal STIM Ca2+ sensing domains, the crystal structures of cytosolic STIM fragments, a closed Orai hexameric crystal structure and a structure of an Orai1 N-terminal fragment in complex with calmodulin. The accessible structural data are discussed in terms of potential mechanisms of action and cohesiveness with functional observations. PMID:24213636

  8. CALCIUM-INDUCED SUPRAMOLECULAR STRUCTURES IN THE CALCIUM CASEINATE SYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The molecular details deciphering the spontaneous calcium-induced protein aggregation process in the calcium caseinate system remain obscure. Understanding this complex process could lead to potential new applications of this important food ingredient. In this work, we studied calcium-induced supra...

  9. Calcium carbonate with magnesium overdose

    MedlinePlus

    The combination of calcium carbonate and magnesium is commonly found in antacids. These medicines provide heartburn relief. Calcium carbonate with magnesium overdose occurs when someone takes more than the ...

  10. Calcium Content of Common Foods

    MedlinePlus

    ... 130 Waffle 80 g 47 Meat, fish and eggs Food Serving Size Calcium (mg) Egg 50 g 27 Red meat 120 g 7 ... foods Food Serving Size Calcium (mg) Quiche (cheese, eggs) 200 g 212 Omelette with cheese 120 g ...

  11. Intestinal Stem Cells: Got Calcium?

    PubMed

    Nászai, Máté; Cordero, Julia B

    2016-02-01

    Calcium ions are well-known intracellular signalling molecules. A new study identifies local cytoplasmic calcium as a central integrator of metabolic and proliferative signals in Drosophila intestinal stem cells. PMID:26859268

  12. Children's Bone Health and Calcium

    MedlinePlus

    ... Trials Resources and Publications Children's Bone Health and Calcium: Condition Information Skip sharing on social media links ... straight, walk, run, and lead an active life. Calcium is one of the key dietary building blocks ...

  13. Synthesis, characterization and crystal structures of the bidentate Schiff base N,N'-bis(2-nitrocinnamaldehyde)ethylenediamine and its complex with CuNCS and triphenylphosphane.

    PubMed

    Clegg, William; Harrington, Ross W; Barati, Kazem; Habibi, Mohammad Hossein; Montazerozohori, Morteza; Lalegani, Arash

    2015-07-01

    Reaction of copper(I) thiocyanate and triphenylphosphane with the bidentate Schiff base N,N'-bis(trans-2-nitrocinnamaldehyde)ethylenediamine {Nca2en, (1); systematic name (1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]}, C20H18N4O4, in a 1:1:1 molar ratio in acetonitrile resulted in the formation of the complex {(1E,1'E,2E,2'E)-N,N'-(ethane-1,2-diyl)bis[3-(2-nitrophenyl)prop-2-en-1-imine]-κ(2)N,N'}(thiocyanato-κN)(triphenylphosphane-κP)copper(I)], [Cu(NCS)(C20H18N4O4)(C18H15P)] or [Cu(NCS)(Nca2en)(PPh3)], (2). The Schiff base and copper(I) complex have been characterized by elemental analyses, IR, electronic and (1)H NMR spectroscopy, and X-ray crystallography [from synchrotron data for (1)]. The molecule of (1) lies on a crystallographic inversion centre, with a trans conformation for the ethylenediamine unit, and displays significant twists from coplanarity of its nitro group, aromatic ring, conjugated chain and especially ethylenediamine segments. It acts as a bidentate ligand coordinating via the imine N atoms to the Cu(I) atom in complex (2), in which the ethylenediamine unit necessarily adopts a somewhat flattened gauche conformation, resulting in a rather bowed shape overall for the ligand. The NCS(-) ligand is coordinated through its N atom. The geometry around the Cu(I) atom is distorted tetrahedral, with a small N-Cu-N bite angle of 81.56 (12)° and an enlarged opposite angle of 117.29 (9)° for SCN-Cu-P. Comparisons are made with the analogous Schiff base having no nitro substituents and with metal complexes of both ligands. PMID:26146396

  14. A Tiered Framework for Risk-Relevant Characterization and Ranking of Chemical Exposures: Applications to the National Children’s Study (NCS)

    PubMed Central

    Georgopoulos, Panos G.; Brinkerhoff, Christopher J.; Isukapalli, Sastry; Dellarco, Michael; Landrigan, Philip J.; Lioy, Paul J.

    2014-01-01

    A challenge for large-scale environmental health investigations such as the National Children’s Study (NCS), is characterizing exposures to multiple, co-occurring chemical agents with varying spatiotemporal concentrations and consequences modulated by biochemical, physiological, behavioral, socioeconomic, and environmental factors. Such investigations can benefit from systematic retrieval, analysis, and integration of diverse extant information on both contaminant patterns and exposure-relevant factors. This requires development, evaluation, and deployment of informatics methods that support flexible access and analysis of multiattribute data across multiple spatiotemporal scales. A new “Tiered Exposure Ranking” (TiER) framework, developed to support various aspects of risk-relevant exposure characterization, is described here, with examples demonstrating its application to the NCS. TiER utilizes advances in informatics computational methods, extant database content and availability, and integrative environmental/exposure/biological modeling to support both “discovery-driven” and “hypothesis-driven” analyses. “Tier 1” applications focus on “exposomic” pattern recognition for extracting information from multidimensional data sets, whereas second and higher tier applications utilize mechanistic models to develop risk-relevant exposure metrics for populations and individuals. In this article, “tier 1” applications of TiER explore identification of potentially causative associations among risk factors, for prioritizing further studies, by considering publicly available demographic/socioeconomic, behavioral, and environmental data in relation to two health endpoints (preterm birth and low birth weight). A “tier 2” application develops estimates of pollutant mixture inhalation exposure indices for NCS counties, formulated to support risk characterization for these endpoints. Applications of TiER demonstrate the feasibility of developing risk

  15. Synthesis, structural and electrical properties of [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2}

    SciTech Connect

    Karoui, Sahel; Kamoun, Slaheddine; Jouini, Amor

    2013-01-15

    Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2} reveals that the adjacent Sn(II) centres are bridged by a pair of SCN{sup -} anions to form a 1-D array giving rise to the anionic chains (SnCl(NCS){sub 2}){sub n}{sup n-}. These chains are themselves interconnected by means of N-H Horizontal-Ellipsis Cl(S) hydrogen bonds originating from the organic cation [(NH{sub 3}){sub 2}(CH{sub 2}){sub 2}]{sup 2+}. The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. - Graphical abstract: Atomic coordination in [C2H10N2][SnCl(NCS)2)2]. Highlights: Black-Right-Pointing-Pointer X-ray diffraction analysis shows the 1D network character of the structure. Black-Right-Pointing-Pointer DSC experiments show a phase transition at 336 K. Black-Right-Pointing-Pointer The AC conductivity is interpreted in terms of Jonsher's law. Black-Right-Pointing-Pointer Two conduction mechanisms are proposed for phase I and II.

  16. Zeeman-driven phase transition within the superconducting state of {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}.

    SciTech Connect

    Wright, J. A.; Green, E.; kuhns, P.; Reyes, A.; Brooks, J.; Schlueter, J.; Kato, R.; Yamamoto, H.; Kobayashi, M.; Brown , S. E.

    2011-08-16

    {sup 13}C nuclear magnetic resonance measurements were performed on {kappa}-(BEDT-TTF){sub 2}Cu(NCS){sub 2}, with the external field placed parallel to the quasi-2D conducting layers. The absorption spectrum is used to determine the electronic spin polarization M{sub s} as a function of external field H at a temperature T = 0.35 K. A discontinuity in the derivative dM{sub s}/dH at an applied field of H{sub s} = 213 {+-} 3 kOe is taken as evidence for a Zeeman-driven transition within the superconducting state and stabilization of inhomogeneous superconductivity.

  17. Calcium and phosphorus fluxes during hemodialysis with low calcium dialysate.

    PubMed

    Hou, S H; Zhao, J; Ellman, C F; Hu, J; Griffin, Z; Spiegel, D M; Bourdeau, J E

    1991-08-01

    We evaluated the acute effects of varying dialysate calcium concentration on plasma concentrations and dialyzer fluxes of calcium and phosphorus in adult hemodialysis patients. Seven individuals with stable end-stage renal failure were dialyzed 4 hours, three times weekly. The effects of dialysates containing 1.75, 1.25, or 0.75 mmol/L (70.1, 50.1, or 30.1 mg/L) of calcium were compared. Each patient was studied once at each bath calcium concentration. Compared with the predialysis mean value of 2.27 mmol/L (9.1 mg/dL), plasma total calcium concentration increased, remained constant, or decreased with the 1.75-, 1.25-, or 0.75-mmol/L calcium dialysates, respectively. The 0.75-mmol/L calcium dialysate did not cause signs or symptoms of hypocalcemia (and the plasma calcium concentration did not fall below 1.80 mmol/L [7.2 mg/dL]). Plasma phosphorus concentrations decreased equally from a predialysis mean value of 2.16 mmol/L (6.7 mg/dL), regardless of the dialysate calcium concentration. After 4 hours of treatment with the three different dialysates, the cumulative calcium fluxes were significantly different. With 1.75 mmol/L calcium, mean bodily calcium accumulation was 21.9 mmol (879 mg). With 1.25 mmol/L, there was no net calcium flux. With 0.75 mmol/L, mean patient calcium loss was 5.8 mmol (231 mg). Mean phosphorus removal after 4 hours was 32.5 mmol (1,006 mg) and was unaffected by dialysate calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1867178

  18. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Adequate intakes of vitamin D and calcium are essential preventative measures and essential components of any therapeutic regimen for osteoporosis. Vitamin D is also important for the prevention of falls. Current evidence suggests that a 25-hydroxyvitamin D level of 75 nmol/L (30 ng/ml) or higher ...

  19. High Blood Calcium (Hypercalcemia)

    MedlinePlus

    ... as sarcoidosis • Hormone disorders, such as overactive thyroid (hyperthyroidism) • A genetic condition called familial hypocalciuric hypercalcemia • Kidney ... topics: www.hormone.org (search for PHPT, calcium, hyperthyroidism, or osteoporosis) • MedlinePlus (National Institutes of Health-NIH): ...

  20. Calcium silicate insulation structure

    DOEpatents

    Kollie, Thomas G.; Lauf, Robert J.

    1995-01-01

    An insulative structure including a powder-filled evacuated casing utilizes a quantity of finely divided synthetic calcium silicate having a relatively high surface area. The resultant structure-provides superior thermal insulating characteristics over a broad temperature range and is particularly well-suited as a panel for a refrigerator or freezer or the insulative barrier for a cooler or a insulated bottle.

  1. Diet and calcium stones.

    PubMed Central

    Hughes, J; Norman, R W

    1992-01-01

    OBJECTIVE: To review the current literature on the dietary modification of urinary risk factors as a means of reducing the likelihood of recurrent stone formation and to develop practical dietary recommendations that might be useful to this end. DATA SOURCES: MEDLINE was searched for English-language articles published from 1983 to 1990. Additional references were selected from the bibliographies of identified articles. STUDY SELECTION: Nonrandomized trials and retrospective reviews were included because of a paucity of randomized controlled trials. DATA SYNTHESIS: Information on the dietary intake of calcium, oxalate, protein, sodium and fibre and on alcohol and fluid intake was used to develop practical guidelines on dietary modification. CONCLUSION: Dietary modification plays an important role in the reduction of urinary risk factors in patients with calcium stone disease of the urinary tract. As an initial form of prevention attention should be directed toward moderating the intake of calcium, oxalate, protein, sodium and alcohol and increasing the intake of fibre and water. Future research should include an assessment of the long-term reduction of dietary and urinary risk factors and the rates of recurrence of calcium stones. PMID:1310430

  2. Calcium biofortification of crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    More than half of the world's population is deficient in calcium (Ca), iron (Fe), iodine (I), magnesium (Mg), selenium (Se), or zinc (Zn). The consumption of plants, directly or via livestock, containing inadequate concentrations of particular minerals causes these deficiencies. Agronomic and geneti...

  3. The Plasma Membrane Calcium Pump

    NASA Technical Reports Server (NTRS)

    Rasmussen, H.

    1983-01-01

    Three aspect of cellular calcium metabolism in animal cells was discussed including the importance of the plasma membrane in calcium homeostasis, experiments dealing with the actual mechanism of the calcium pump, and the function of the pump in relationship to the mitochondria and to the function of calmodulin in the intact cell.

  4. Impregnating Coal With Calcium Carbonate

    NASA Technical Reports Server (NTRS)

    Sharma, Pramod K.; Voecks, Gerald E.; Gavalas, George R.

    1991-01-01

    Relatively inexpensive process proposed for impregnating coal with calcium carbonate to increase rates of gasification and combustion of coal and to reduce emission of sulfur by trapping sulfur in calcium sulfide. Process involves aqueous-phase reactions between carbon dioxide (contained within pore network of coal) and calcium acetate. Coal impregnated with CO2 by exposing it to CO2 at high pressure.

  5. Photoelastic sensors

    SciTech Connect

    Kulakov, G.I.

    1985-07-01

    This paper presents the result of a study of photoelastic sensors which makes it possible to explain many mechanical and physical features of the operation of annular photoelastic borehole sensors and to plan ways of utilizing these features for interpreting the sensor readings.

  6. Voltage-Gated Calcium Channels

    NASA Astrophysics Data System (ADS)

    Zamponi, Gerald Werner

    Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

  7. Structure-function relationship of a plant NCS1 member--homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from Arabidopsis.

    PubMed

    Witz, Sandra; Panwar, Pankaj; Schober, Markus; Deppe, Johannes; Pasha, Farhan Ahmad; Lemieux, M Joanne; Möhlmann, Torsten

    2014-01-01

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. PMID:24621654

  8. Structure-Function Relationship of a Plant NCS1 Member – Homology Modeling and Mutagenesis Identified Residues Critical for Substrate Specificity of PLUTO, a Nucleobase Transporter from Arabidopsis

    PubMed Central

    Witz, Sandra; Panwar, Pankaj; Schober, Markus; Deppe, Johannes; Pasha, Farhan Ahmad; Lemieux, M. Joanne; Möhlmann, Torsten

    2014-01-01

    Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. PMID:24621654

  9. Fruit Calcium: Transport and Physiology

    PubMed Central

    Hocking, Bradleigh; Tyerman, Stephen D.; Burton, Rachel A.; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  10. Fruit Calcium: Transport and Physiology.

    PubMed

    Hocking, Bradleigh; Tyerman, Stephen D; Burton, Rachel A; Gilliham, Matthew

    2016-01-01

    Calcium has well-documented roles in plant signaling, water relations and cell wall interactions. Significant research into how calcium impacts these individual processes in various tissues has been carried out; however, the influence of calcium on fruit ripening has not been thoroughly explored. Here, we review the current state of knowledge on how calcium may impact the development, physical traits and disease susceptibility of fruit through facilitating developmental and stress response signaling, stabilizing membranes, influencing water relations and modifying cell wall properties through cross-linking of de-esterified pectins. We explore the involvement of calcium in hormone signaling integral to the physiological mechanisms behind common disorders that have been associated with fruit calcium deficiency (e.g., blossom end rot in tomatoes or bitter pit in apples). This review works toward an improved understanding of how the many roles of calcium interact to influence fruit ripening, and proposes future research directions to fill knowledge gaps. Specifically, we focus mostly on grapes and present a model that integrates existing knowledge around these various functions of calcium in fruit, which provides a basis for understanding the physiological impacts of sub-optimal calcium nutrition in grapes. Calcium accumulation and distribution in fruit is shown to be highly dependent on water delivery and cell wall interactions in the apoplasm. Localized calcium deficiencies observed in particular species or varieties can result from differences in xylem morphology, fruit water relations and pectin composition, and can cause leaky membranes, irregular cell wall softening, impaired hormonal signaling and aberrant fruit development. We propose that the role of apoplasmic calcium-pectin crosslinking, particularly in the xylem, is an understudied area that may have a key influence on fruit water relations. Furthermore, we believe that improved knowledge of the calcium

  11. Nutrition in calcium nephrolithiasis

    PubMed Central

    2013-01-01

    Idiopathic calcium nephrolithiasis is a multifactorial disease with a complex pathogenesis due to genetic and environmental factors. The importance of social and health effects of nephrolithiasis is further highlighted by the strong tendency to relapse of the disease. Long-term prospective studies show a peak of disease recurrence within 2–3 years since onset, 40-50% of patients have a recurrence after 5 years and more than 50-60% after 10 years. International nutritional studies demonstrated that nutritional habits are relevant in therapy and prevention approaches of nephrolithiasis. Water, right intake of calcium, low intake of sodium, high levels of urinary citrate are certainly important for the primary and secondary prevention of nephrolithiasis. In this review is discussed how the correction of nutritional mistakes can reduce the incidence of recurrent nephrolithiasis. PMID:23634702

  12. DISTILLATION OF CALCIUM

    DOEpatents

    Barton, J.

    1954-07-27

    This invention relates to an improvement in the process for the purification of caicium or magnesium containing an alkali metal as impurity, which comprises distiiling a batch of the mixture in two stages, the first stage distillation being carried out in the presence of an inert gas at an absolute pressure substantially greater than the vapor pressure of calcium or maguesium at the temperature of distillation, but less than the vaper pressure at that temperature of the alkali metal impurity so that only the alkali metal is vaporized and condensed on a condensing surface. A second stage distilso that substantially only the calcium or magnesium distills under its own vapor pressure only and condenses in solid form on a lower condensing surface.

  13. Synthesis of calcium superoxide

    NASA Technical Reports Server (NTRS)

    Rewick, R. T.; Blucher, W. G.; Estacio, P. L.

    1972-01-01

    Efforts to prepare Ca(O2) sub 2 from reactions of calcium compounds with 100% O3 and with O(D-1) atoms generated by photolysis of O3 at 2537 A are described. Samples of Ca(OH) sub 2, CaO, CaO2, Ca metal, and mixtures containing suspected impurities to promote reaction have been treated with excess O3 under static and flow conditions in the presence and absence of UV irradiation. Studies with KO2 suggest that the superoxide anion is stable to radiation at 2537 A but reacts with oxygen atoms generated by the photolysis of O3 to form KO3. Calcium superoxide is expected to behave in an analogous.

  14. Complexometric Determination of Calcium

    NASA Astrophysics Data System (ADS)

    Nielsen, S. Suzanne

    Ethylenediaminetetraacetate (EDTA) complexes with numerous mineral ions, including calcium and magnesium. This reaction can be used to determine the amount of these minerals in a sample by a complexometric titration. Endpoints in the titration are detected using indicators that change color when they complex with mineral ions. Calmagite and eriochrome black T (EBT) are such indicators that change from blue to pink when they complex with calcium and magnesium. In the titration of a mineral-containing solution with EDTA, the solution turns from pink to blue at the endpoint with either indicator. The pH affects a complexometric EDTA titration in several ways, and must be carefully controlled. A major application of EDTA titration is testing the hardness of water, for which the method described is an official one (Standard Methods for the Examination of Water and Wastewater, Method 2340C; AOAC Method 920.196).

  15. Prebiotics and calcium bioavailability.

    PubMed

    Cashman, Kevin

    2003-03-01

    A prebiotic substance has been defined as a non-digestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon. Therefore, compared to probiotics, which introduce exogenous bacteria into the colonic microflora, a prebiotic aims at stimulating the growth of one or a limited number of the potentially health-promoting indigenous micro-organisms, thus modulating the composition of the natural ecosystem. In recent years, increasing attention has been focussed on the possible beneficial effects of prebiotics, such as enhanced resistance to invading pathogens, improved bowel function, anti-colon cancer properties, lipid lowering action, improved calcium bioavailability, amongst others. The objective of this review is to critically assess the available data on the effects of prebiotics on calcium bioavailability, and place it in the context of human physiology and, when possible, explain the underlying cellular and molecular mechanisms. The review will also try to highlight future areas of research that may help in the evaluation of prebiotics as potential ingredients for functional foods aimed at enhancing calcium bioavailability and protecting against osteoporosis. PMID:12691259

  16. [Calcium--essential for everybody].

    PubMed

    Cichosz, Grazyna; Czeczot, Hanna

    2014-06-01

    Calcium regulates majority of metabolic processes within human organism and its optimal intake decreases risk of metabolic illnesses conditioned by diet. Deficiency of calcium results in higher body max index, increase risk of insulin resistance, diabetes type 2 and osteoporosis. Diet delivering full calcium load diminished impendency of hypertension; calcium regulates tension of smooth muscles of blood vessels, limits neurotransmitters activity and also diminish hazardous activity of sodium chloride. Anticancerogenic activity of calcium results from formation insoluble bile acids and fat acids salts, and most of all, from inhibition of intestine mucosa cells hyper proliferation. Due to presence of vitamin D3, CLA, proteins and bioactive peptides emerging from them, milk is more efficient in prophylaxis of diet conditioned illnesses than calcium supplements. Efficiency of milk and dairy products in treatment of obesity, sclerosis and hypertension has been proved by DASH diet. PMID:25095643

  17. Sensor web

    NASA Technical Reports Server (NTRS)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  18. Changes in gravity rapidly alter the magnitude and direction of a cellular calcium current.

    PubMed

    Salmi, Mari L; ul Haque, Aeraj; Bushart, Thomas J; Stout, Stephen C; Roux, Stanley J; Porterfield, D Marshall

    2011-05-01

    In single-celled spores of the fern Ceratopteris richardii, gravity directs polarity of development and induces a directional, trans-cellular calcium (Ca(2+)) current. To clarify how gravity polarizes this electrophysiological process, we measured the kinetics of the cellular response to changes in the gravity vector, which we initially estimated using the self-referencing calcium microsensor. In order to generate more precise and detailed data, we developed a silicon microfabricated sensor array which facilitated a lab-on-a-chip approach to simultaneously measure calcium currents from multiple cells in real time. These experiments revealed that the direction of the gravity-dependent polar calcium current is reversed in less than 25 s when the cells are inverted, and that changes in the magnitude of the calcium current parallel rapidly changing g-forces during parabolic flight on the NASA C-9 aircraft. The data also revealed a hysteresis in the response of cells in the transition from 2g to micro-g in comparison to cells in the micro-g to 2-g transition, a result consistent with a role for mechanosensitive ion channels in the gravity response. The calcium current is suppressed by either nifedipine (calcium-channel blocker) or eosin yellow (plasma membrane calcium pump inhibitor). Nifedipine disrupts gravity-directed cell polarity, but not spore germination. These results indicate that gravity perception in single plant cells may be mediated by mechanosensitive calcium channels, an idea consistent with some previously proposed models of plant gravity perception. PMID:21234599

  19. Calcium Kinetics During Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Wastney, Meryl E.; OBrien, Kimberly O.; Lane, Helen W.

    1999-01-01

    Bone loss is one of the most detrimental effects of space flight, threatening to limit the duration of human space missions. The ability to understand and counteract this loss will be critical for crew health and safety during and after extended-duration missions. The hypotheses to be tested in this project are that space flight alters calcium homeostasis and bone mineral metabolism, and that calcium homeostasis and bone mineral metabolism will return to baseline within days to weeks of return to Earth. These hypotheses will be evidenced by elevated rates of bone mineral resorption and decreased bone mineral deposition, decreased absorption of dietary calcium, altered calcitropic endocrine profiles, elevated excretion of calcium in urine and feces, and elevated excretion of markers of bone resorption. The second hypothesis will be evidenced by return of indices of calcium homeostasis and bone metabolism to preflight levels within days to weeks of return to Earth. Studies will be conducted on International Space Station astronauts before, during, and after extended-duration flights. Measurements of calcium kinetics, bone mass, and endocrine/biochemical markers of bone and calcium homeostasis will be conducted. Kinetic studies utilizing dual isotope tracer kinetic studies and mathematical modeling techniques will allow for determination of bone calcium deposition, bone calcium resorption, dietary calcium absorption and calcium excretion (both urinary and endogenous fecal excretion). These studies will build upon preliminary work conducted on the Russian Mir space station. The results from this project will be critical for clarifying how microgravity affects bone and calcium homeostasis, and will provide an important control point for assessment of countermeasure efficacy. These results are expected to aid in developing countermeasures for bone loss, both for space crews and for individuals on Earth who have metabolic bone diseases.

  20. Mechanisms of intestinal calcium absorption.

    PubMed

    Bronner, Felix

    2003-02-01

    Calcium is absorbed in the mammalian small intestine by two general mechanisms: a transcellular active transport process, located largely in the duodenum and upper jejunum; and a paracellular, passive process that functions throughout the length of the intestine. The transcellular process involves three major steps: entry across the brush border, mediated by a molecular structure termed CaT1, intracellular diffusion, mediated largely by the cytosolic calcium-binding protein (calbindinD(9k) or CaBP); and extrusion, mediated largely by the CaATPase. Chyme travels down the intestinal lumen in approximately 3 h, spending only minutes in the duodenum, but over 2 h in the distal half of the small intestine. When calcium intake is low, transcellular calcium transport accounts for a substantial fraction of the absorbed calcium. When calcium intake is high, transcellular transport accounts for only a minor portion of the absorbed calcium, because of the short sojourn time and because CaT1 and CaBP, both rate-limiting, are downregulated when calcium intake is high. Biosynthesis of CaBP is fully and CaT1 function is approximately 90% vitamin D-dependent. At high calcium intakes CaT1 and CaBP are downregulated because 1,25(OH)(2)D(3), the active vitamin D metabolite, is downregulated. PMID:12520541

  1. Calcium channel blockers and dementia

    PubMed Central

    Nimmrich, V; Eckert, A

    2013-01-01

    Degenerative dementia is mainly caused by Alzheimer's disease and/or cerebrovascular abnormalities. Disturbance of the intracellular calcium homeostasis is central to the pathophysiology of neurodegeneration. In Alzheimer's disease, enhanced calcium load may be brought about by extracellular accumulation of amyloid-β. Recent studies suggest that soluble forms facilitate influx through calcium-conducting ion channels in the plasma membrane, leading to excitotoxic neurodegeneration. Calcium channel blockade attenuates amyloid-β-induced neuronal decline in vitro and is neuroprotective in animal models. Vascular dementia, on the other hand, is caused by cerebral hypoperfusion and may benefit from calcium channel blockade due to relaxation of the cerebral vasculature. Several calcium channel blockers have been tested in clinical trials of dementia and the outcome is heterogeneous. Nimodipine as well as nilvadipine prevent cognitive decline in some trials, whereas other calcium channel blockers failed. In trials with a positive outcome, BP reduction did not seem to play a role in preventing dementia, indicating a direct protecting effect on neurons. An optimization of calcium channel blockers for the treatment of dementia may involve an increase of selectivity for presynaptic calcium channels and an improvement of the affinity to the inactivated state. Novel low molecular weight compounds suitable for proof-of-concept studies are now available. PMID:23638877

  2. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium alginate. 184.1187 Section 184.1187 Food... GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown algae. Calcium alginate is prepared...

  3. 21 CFR 184.1212 - Calcium pantothenate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate. 184.1212 Section 184.1212... Listing of Specific Substances Affirmed as GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate... and the DL-racemic mixture of calcium pantothenate are used in food. Commercial calcium...

  4. 21 CFR 184.1212 - Calcium pantothenate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium pantothenate. 184.1212 Section 184.1212... Listing of Specific Substances Affirmed as GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate... and the DL- racemic mixture of calcium pantothenate are used in food. Commercial calcium...

  5. 21 CFR 184.1212 - Calcium pantothenate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium pantothenate. 184.1212 Section 184.1212... GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate ((C9H16NO5)2Ca, CAS Reg. No. of the D... calcium pantothenate are used in food. Commercial calcium pantothenate is prepared synthetically...

  6. 21 CFR 184.1212 - Calcium pantothenate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate. 184.1212 Section 184.1212... Listing of Specific Substances Affirmed as GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate... and the DL-racemic mixture of calcium pantothenate are used in food. Commercial calcium...

  7. 21 CFR 184.1212 - Calcium pantothenate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium pantothenate. 184.1212 Section 184.1212... Listing of Specific Substances Affirmed as GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate... and the DL-racemic mixture of calcium pantothenate are used in food. Commercial calcium...

  8. Antiferromagnetism in a Family of S = 1 Square Lattice Coordination Polymers NiX2(pyz)2 (X = Cl, Br, I, NCS; pyz = Pyrazine).

    PubMed

    Liu, Junjie; Goddard, Paul A; Singleton, John; Brambleby, Jamie; Foronda, Francesca; Möller, Johannes S; Kohama, Yoshimitsu; Ghannadzadeh, Saman; Ardavan, Arzhang; Blundell, Stephen J; Lancaster, Tom; Xiao, Fan; Williams, Robert C; Pratt, Francis L; Baker, Peter J; Wierschem, Keola; Lapidus, Saul H; Stone, Kevin H; Stephens, Peter W; Bendix, Jesper; Woods, Toby J; Carreiro, Kimberly E; Tran, Hope E; Villa, Cecelia J; Manson, Jamie L

    2016-04-01

    The crystal structures of NiX2(pyz)2 (X = Cl (1), Br (2), I (3), and NCS (4)) were determined by synchrotron X-ray powder diffraction. All four compounds consist of two-dimensional (2D) square arrays self-assembled from octahedral NiN4X2 units that are bridged by pyz ligands. The 2D layered motifs displayed by 1-4 are relevant to bifluoride-bridged [Ni(HF2)(pyz)2]EF6 (E = P, Sb), which also possess the same 2D layers. In contrast, terminal X ligands occupy axial positions in 1-4 and cause a staggered packing of adjacent layers. Long-range antiferromagnetic (AFM) order occurs below 1.5 (Cl), 1.9 (Br and NCS), and 2.5 K (I) as determined by heat capacity and muon-spin relaxation. The single-ion anisotropy and g factor of 2, 3, and 4 were measured by electron-spin resonance with no evidence for zero-field splitting (ZFS) being observed. The magnetism of 1-4 spans the spectrum from quasi-two-dimensional (2D) to three-dimensional (3D) antiferromagnetism. Nearly identical results and thermodynamic features were obtained for 2 and 4 as shown by pulsed-field magnetization, magnetic susceptibility, as well as their Néel temperatures. Magnetization curves for 2 and 4 calculated by quantum Monte Carlo simulation also show excellent agreement with the pulsed-field data. Compound 3 is characterized as a 3D AFM with the interlayer interaction (J⊥) being slightly stronger than the intralayer interaction along Ni-pyz-Ni segments (J(pyz)) within the two-dimensional [Ni(pyz)2](2+) square planes. Regardless of X, J(pyz) is similar for the four compounds and is roughly 1 K. PMID:27002487

  9. Synthesis of a New Bimetallic Re(I)-NCS-Pt(II) Complex as Chemodosimetric Ensemble for the Selective Detection of Mercapto-Containing Pesticides.

    PubMed

    Chow, Cheuk-Fai; Ho, Keith Yat-Fung; Gong, Cheng-Bin

    2015-06-16

    Detection of mercapto-containing pesticides plays a crucial role in food and water safety. A new Re(I)-NCS-Pt(II) complex, [Re(4,4'-di-tert-butyl-2,2'-bipyridine)(CO)3(NCS)]-[Pt(DMSO)(Cl)2] (1), was synthesized and characterized. The synthetic procedure, characterization results, and photophysical data for 1 are reported in this paper. Solvated complex 1 demonstrated luminescent chemodosimetric selectivity for phorate, demeton, and aldicarb (three common mercapto-containing pesticides) with method detection limits (MDLs) of 1.00, 2.87, and 2.08 ppm, respectively. The binding constants (log K) of 1 toward them were in the 3.24-3.44 range. The analyte selectivity of the complex was found to be dependent on the bridging linkage (C≡N and N═C═S) between the Re(I) and Pt(II) centers. The solid-supported dosimetric device 1 was fabricated by blending complex 1 with Al2O3 and poly(vinyl chloride) (PVC) powder. The MDLs of the device toward the mercapto-containing pesticides were 0.48-0.60 ppm. The device was applicable to pesticides in real water bodies such as taps, rivers, lakes, and underground water bodies with excellent recoveries and relative standard deviations of 76.2-108.0% and 2.9-6.7%, respectively. Its spectrofluorimetric changes could be analyzed by naked eye within 20 min with a linear luminometric response toward increases in the phorate concentration (0-8.0 ppm) with R = 0.999. PMID:26039794

  10. A comprehensive search for calcium binding sites critical for TMEM16A calcium-activated chloride channel activity.

    PubMed

    Tien, Jason; Peters, Christian J; Wong, Xiu Ming; Cheng, Tong; Jan, Yuh Nung; Jan, Lily Yeh; Yang, Huanghe

    2014-01-01

    TMEM16A forms calcium-activated chloride channels (CaCCs) that regulate physiological processes such as the secretions of airway epithelia and exocrine glands, the contraction of smooth muscles, and the excitability of neurons. Notwithstanding intense interest in the mechanism behind TMEM16A-CaCC calcium-dependent gating, comprehensive surveys to identify and characterize potential calcium sensors of this channel are still lacking. By aligning distantly related calcium-activated ion channels in the TMEM16 family and conducting systematic mutagenesis of all conserved acidic residues thought to be exposed to the cytoplasm, we identify four acidic amino acids as putative calcium-binding residues. Alterations of the charge, polarity, and size of amino acid side chains at these sites alter the ability of different divalent cations to activate the channel. Furthermore, TMEM16A mutant channels containing double cysteine substitutions at these residues are sensitive to the redox potential of the internal solution, providing evidence for their physical proximity and solvent accessibility. PMID:24980701

  11. Temperature Sensor

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Weed Instrument Inc. produces a line of thermocouples - temperature sensors - for a variety of industrial and research uses. One of the company's newer products is a thermocouple specially designed for high accuracy at extreme temperatures above 3,000 degrees Fahrenheit. Development of sensor brought substantial increases in Weed Instrument sales and employment.

  12. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  13. Chemical sensors

    SciTech Connect

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section.

  14. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate...

  15. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate...

  16. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate...

  17. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate...

  18. 21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium pantothenate, calcium chloride double salt... Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may be safely used in foods for...

  19. Recent developments in intestinal calcium absorption.

    PubMed

    Bronner, Felix

    2009-02-01

    Calcium absorption proceeds by transcellular and paracellular flux, with the latter accounting for most absorbed calcium when calcium intake is adequate. Vitamin D helps regulate transcellular calcium transport by increasing calcium uptake via a luminal calcium channel and by inducing the cytosolic calcium transporting protein, calbindinD(9k). Recent studies utilizing knockout mice have challenged the functional importance of the channel and calbindin. To integrate the new findings with many previous studies, the function of the two molecules must be evaluated in the calcium transport and economy of mice. When calcium intake is high, transcellular calcium transport contributes little to total calcium absorption. Therefore, increasing calcium intake seems the most effective nutritional approach to ensure adequate absorption and prevent bone loss. PMID:19178653

  20. Calcium, vitamin D, and your bones

    MedlinePlus

    ... medlineplus.gov/ency/patientinstructions/000490.htm Calcium, vitamin D, and your bones To use the sharing features ... maintain strong bones. How Much Calcium and Vitamin D Do I Need? Amounts of calcium are given ...

  1. Vitamin D, Calcium, and Bone Health

    MedlinePlus

    ... Balance › Vitamin D, Calcium, and Bone Health Vitamin D, Calcium, and Bone Health March 2012 Download PDFs ... helps keep your bones strong. Why are vitamin D and calcium important to bone health? Vitamin D ...

  2. Calcium transporters: From fields to the table

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium transporters regulate calcium fluxes within cells. Plants, like all organisms, contain channels, pumps, and exchangers to carefully modulate intracellular calcium levels. This review presents a summary of the recent advances in cloning and characterizing of these transporters and highlight...

  3. Major Minerals - Calcium, Magnesium, Phosphorus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium, magnesium and phosphorus are essential elements critically important for the function of the musculoskeletal system, including the formation and transduction of energy and the maintenance of healthy bone. The major calcium concern for physically active healthy middle-aged adults is to consu...

  4. Calcium Intake: A Lifelong Proposition.

    ERIC Educational Resources Information Center

    Amschler, Denise H.

    1985-01-01

    This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)

  5. Electrochemical cell with calcium anode

    DOEpatents

    Cooper, John F.; Hosmer, Pamela K.; Kelly, Benjamin E.

    1979-01-01

    An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

  6. Fabrication and Tailoring Plasmonic Properties of Two Dimensional Assemblies of Metal Nanostructures towards Engineering Novel Plasmonic Sensors

    NASA Astrophysics Data System (ADS)

    Ahamad, Nur Uddin

    Electromagnetic mechanism of enhancement, proposed to elucidate surface enhanced Raman scattering (SERS) and Surface enhanced fluorescence (SEF), was justified by studying distance dependent enhancement of SERS and SEF using 2D self-assembled spheroidal silver nanoparticles containing probe molecules. Spacer layer between the metal surface and the probe was created by layer-by-layer deposition of oppositely charged polyelectrolytes. A decreasing trend in SERS enhancement factor and an increasing trend in SEF enhancement factor with increasing separation distance were observed, which corroborate with proposed electromagnetic mechanism of SERS and SEF. In order to fabricate effective SERS substrates by exploiting hot spots, supported 2D assemblies of silver nanocubes (NCs) with controlled interparticles distance were fabricated using LB technique. Interparticles distance in such substrates was tailored by incorporation of NCs in phospholipid monolayers in Langmuir trough and optimizing lateral surface pressure during the film transfer onto a solid surface. However, to develop plasmonic sensors with high refractive index sensitivity (RIS), investigation was performed to optimize RIS of supported and colloidal silver NCs. The size of the NCs, RI of supporting dielectric substrate, and the monolayer surface pressure were used as variables in refractive index sensing optimization. It was found that high refractive index dielectric substrates, a passive molecular spacer and large angles of incidence facilitate the detection of plasmonic response of supported 2D assemblies of nanocubes. Furthermore, a simple and robust strategy was demonstrated for assembling silver NCs into 2D hierarchical structures (uniform rounded islands, branched-parallel chains) on LB films exploiting phase behaviors of multi-components lipid mixtures in Langmuir films. The density of the building blocks, size and shape of the resulting patterns can be controlled by tailoring the lateral surface

  7. Effect of Ca2+ on the Steady-State and Time-Resolved Emission Properties of the Genetically Encoded Fluorescent Sensor CatchER

    PubMed Central

    2015-01-01

    We previously designed a calcium sensor CatchER (a GFP-based Calcium sensor for detecting high concentrations in the high calcium concentration environment such as ER) with a capability for monitoring calcium ion responses in various types of cells. Calcium binding to CatchER induces the ratiometric changes in the absorption spectra, as well as an increase in fluorescence emission at 510 nm upon excitation at both 395 and 488 nm. Here, we have applied the combination of the steady-state and time-resolved optical methods and Hydrogen/Deuterium isotope exchange to understand the origin of such calcium-induced optical property changes of CatchER. We first demonstrated that calcium binding results in a 44% mean fluorescence lifetime increase of the indirectly excited anionic chromophore. Thus, CatchER is the first protein-based calcium indicator with the single fluorescent moiety to show the direct correlation between the lifetime and calcium binding. Calcium exhibits a strong inhibition on the excited-state proton transfer nonadiabatic geminate recombination in protic (vs deuteric) medium. Analysis of CatchER crystal structures and the MD simulations reveal the proton transfer mechanism in which the disrupted proton migration path in CatchER is rescued by calcium binding. Our finding provides important insights for a strategy to design calcium sensors and suggests that CatchER could be a useful probe for FLIM imaging of calcium in situ. PMID:24836743

  8. Synthesis, crystal structure, and magnetic properties of the coordination polymer [Fe(NCS)2(1,2-bis(4-pyridyl)-ethylene)]n showing a two step metamagnetic transition.

    PubMed

    Wöhlert, Susanne; Wriedt, Mario; Fic, Tomasz; Tomkowicz, Zbigniew; Haase, Wolfgang; Näther, Christian

    2013-01-18

    Reaction of iron(II) thiocyanate with an excess of trans-1,2-bis(4-pyridyl)-ethylene (bpe) in acetonitrile at room temperature leads to the formation of [Fe(NCS)(2)(bpe)(2)·(bpe)] (1), which is isotypic to its Co(II) analogue. Using slightly different reaction conditions the literature known compound [Fe(NCS)(2)(bpe)(2)(H(2)O)(2)] (2) was obtained as a phase pure material. Simultaneous differential thermoanalysis and thermogravimetry prove that the hydrate 2 transforms into the anhydrate [Fe(NCS)(2)(bpe)(2)] (3), that decomposes on further heating into the new ligand-deficient 1:1 compound of composition [Fe(NCS)(2)(bpe)](n) (4), which can also be obtained directly by thermal decomposition of 1. Further investigations reveal that 4 can also be prepared under solvothermal conditions, and single crystal structure analysis shows that the iron(II) cations are linked via μ-1,3 bridging thiocyanato anions into chains, that are further connected into layers by the bpe ligands. Magnetic measurements, performed on powder samples, prove that 1 and 2 show only Curie-Weiss behavior, whereas in 4 antiferromagnetic ordering with a Néel temperature of 5.0 K is observed. At T < 4.0 K a two-step metamagnetic transition occurs at applied magnetic fields of 1300 and 1775 Oe. The magnetic properties are discussed and compared with those of related compounds. PMID:23276282

  9. Diffusion in calcium oxide/calcium sulfate pellets

    SciTech Connect

    Chang, K.L.

    1981-10-01

    Diffusion rates in calcium oxide pellets after partial conversion to calcium sulfate were measured. A Wicke-Kallenbach type diffusion cell operated in the pulse-response mode was used to measure effective diffusivity. Cylindrical calcium oxide pellets were formed from the powder using pelletizing pressures of 10,000, 20,000 and 30,000 psi. The pellets were reacted at 325, 500 and 600/sup 0/C with sulfur dioxide and oxygen to form calcium sulfate. The volume of calcium sulfate is 2.7 times that of calcium oxide, so partial pore closure occurs. The diffusivity was measured in the original pellet and in pellets partially reacted to several different conversion levels. The effective diffusivity decreases as conversion decreases and is roughly inversely proportional to pellet porosity squared for low conversions. However, the porosity and diffusion rate do not become zero when the reaction rate approaches zero. Pore closure is, therefore, not the mechanism which limits the ultimate conversion. A large diffusion resistance through the calcium sulfate product layer probably causes the reaction to stop before total conversion. The final conversion obtainable increases as reaction temperature increases and decreases as pelletizing pressure increases.

  10. The activity of calcium in calcium-metal-fluoride fluxes

    NASA Astrophysics Data System (ADS)

    Ochifuji, Yuichiro; Tsukihashi, Fumitaka; Sano, Nobuo

    1995-08-01

    The standard Gibbs energy of reaction Ca (1) + O (mass pct, in Zr) = CaO (s) has been determined as follows by equilibrating molten calcium with solid zirconium in a CaO crucible: Δ G° = -64,300(±700) + 19.8(±3.5) T J/mol (1373 to 1623 K) The activities of calcium in the CaOsatd-Ca- MF2 ( M: Ca, Ba, Mg) and CaOsatd-Ca-NaF systems were measured as a function of calcium composition at high calcium contents at 1473 K on the basis of the standard Gibbs energy. The activities of calcium increase in the order of CaF2, BaF2, and MgF2 at the same calcium fraction of these fluxes. The observed activities are compared with those estimated by using the Temkin model for ionic solutions. Furthermore, the possibility of the removal of tramp elements such as tin, arsenic, antimony, bismuth, and lead from carbon-saturated iron by using calcium-metal-fluoride fluxes is discussed.

  11. The activity of calcium in calcium-metal-fluoride fluxes

    SciTech Connect

    Ochifuji, Yuichiro; Tsukihashi, Fumitaka; Sano, Nobuo

    1995-08-01

    The standard Gibbs energy of reaction Ca (1) + {und O} (mass pct, in Zr) = CaO (s) has been determined as follows by equilibrating molten calcium with solid zirconium in a CaO crucible: {Delta}G{degree} = {minus}64,300({+-}700) + 19.8({+-}3.5)T J/mol (1,373 to 1,623 K). The activities of calcium in the CaO{sub satd.}-Ca-MF{sub 2} (M: Ca, Ba, Mg) and CaO{sub satd.}-Ca-NaF systems were measured as a function of calcium composition at high calcium contents at 1,473 K on the basis of the standard Gibbs energy. The activities of calcium increase in the order of CaF{sub 2}, BaF{sub 2}, and MgF{sub 2} at the same calcium fraction of these fluxes. The observed activities are compared with those estimated by using the Temkin model for ionic solutions. Furthermore, the possibility of the removal of tramp elements such as tin, arsenic, antimony, bismuth, and lead from carbon-saturated iron by using calcium-metal-fluoride fluxes is discussed.

  12. Two mixed-ligand lanthanide–hydrazone complexes: [Pr(NCS)3(pbh)2]·H2O and [Nd(NCS)(NO3)(pbh)2(H2O)]NO3·2.33H2O [pbh is N′-(pyridin-2-ylmethylidene)benzo­hydrazide, C13H11N3O

    PubMed Central

    Paschalidis, Damianos G.; Harrison, William T. A.

    2016-01-01

    The gel-mediated syntheses and crystal structures of [N′-(pyridin-2-ylmethylidene-κN)benzohydrazide-κ2 N′,O]tris(thiocyanato-κN)praseodymium(III) mono­hydrate, [Pr(NCS)3(C13H11N3O)2]·H2O, (I), and aqua(nitrato-κ2 O,O′)[N′-(pyri­din-2-ylmethylidene-κN)benzohydrazide-κ2 N′,O](thiocyanato-κN)neo­dym­ium(III) nitrate 2.33-hydrate, [Nd(NCS)(NO3)(C13H11N3O)2(H2O)]NO3·2.33H2O, (II), are reported. The Pr3+ ion in (I) is coordinated by two N,N,O-tridentate N′-(pyridin-2-ylmethylidene)benzohydrazide (pbh) ligands and three N-bonded thio­cyanate ions to generate an irregular PrN7O2 coordination polyhedron. The Nd3+ ion in (II) is coordinated by two N,N,O-tridentate pbh ligands, an N-bonded thio­cyanate ion, a bidentate nitrate ion and a water mol­ecule to generate a distorted NdN5O5 bicapped square anti­prism. The crystal structures of (I) and (II) feature numerous hydrogen bonds, which lead to the formation of three-dimensional networks in each case. PMID:26958385

  13. Two mixed-ligand lanthanide-hydrazone complexes: [Pr(NCS)3(pbh)2]·H2O and [Nd(NCS)(NO3)(pbh)2(H2O)]NO3·2.33H2O [pbh is N'-(pyridin-2-ylmethylidene)benzo-hydrazide, C13H11N3O].

    PubMed

    Paschalidis, Damianos G; Harrison, William T A

    2016-02-01

    The gel-mediated syntheses and crystal structures of [N'-(pyridin-2-ylmethylidene-κN)benzohydrazide-κ(2) N',O]tris(thiocyanato-κN)praseodymium(III) mono-hydrate, [Pr(NCS)3(C13H11N3O)2]·H2O, (I), and aqua(nitrato-κ(2) O,O')[N'-(pyri-din-2-ylmethylidene-κN)benzohydrazide-κ(2) N',O](thiocyanato-κN)neo-dym-ium(III) nitrate 2.33-hydrate, [Nd(NCS)(NO3)(C13H11N3O)2(H2O)]NO3·2.33H2O, (II), are reported. The Pr(3+) ion in (I) is coordinated by two N,N,O-tridentate N'-(pyridin-2-ylmethylidene)benzohydrazide (pbh) ligands and three N-bonded thio-cyanate ions to generate an irregular PrN7O2 coordination polyhedron. The Nd(3+) ion in (II) is coordinated by two N,N,O-tridentate pbh ligands, an N-bonded thio-cyanate ion, a bidentate nitrate ion and a water mol-ecule to generate a distorted NdN5O5 bicapped square anti-prism. The crystal structures of (I) and (II) feature numerous hydrogen bonds, which lead to the formation of three-dimensional networks in each case. PMID:26958385

  14. Limestone reaction in calcium aluminate cement–calcium sulfate systems

    SciTech Connect

    Bizzozero, Julien Scrivener, Karen L.

    2015-10-15

    This paper reports a study of ternary blends composed of calcium aluminate cement, calcium sulfate hemihydrate and limestone. Compressive strength tests and hydration kinetics were studied as a function of limestone and calcium sulfate content. The phase evolution and the total porosity were followed and compared to thermodynamic simulation to understand the reactions involved and the effect of limestone on these binders. The reaction of limestone leads to the formation of hemicarboaluminate and monocarboaluminate. Increasing the ratio between sulfate and aluminate decreases the extent of limestone reaction.

  15. Sensitivity to calcium intake in calcium stone forming patients.

    PubMed

    Heilberg, I P; Martini, L A; Draibe, S A; Ajzen, H; Ramos, O L; Schor, N

    1996-01-01

    The absorptive or renal origin of hypercalciuria can be discriminated using an acute oral calcium load test (ACLT). Of 86 patients with calcium oxalate kidney stones, 28 (23%) were found to be hypercalciuric (HCa) and 58 (67%) normocalciuric (NCa) on their customary free diet, containing 542 +/- 29 mg/day (mean +/- SE) of calcium. Since the apparently normal 24-hour calcium excretion of many calcium stone formers (CSF) may be due to a combination of high calcium absorption with moderately low calcium intake, all patients were investigated by ACLT. Of 28 HCa patients, 13 (46%) were classified as absorptive (AH) and 15 (54%) as renal hypercalciuria (RH). Of the 58 NCa patients, 38 (65%) presented features of intestinal hyperabsorption and were therefore designated as AH-like, and 20 (35%) as RH-like. To further elucidate the role of dietary calcium in these CSF, a chronic calcium load test (CCLT), consisting of 1 g/day of oral Ca for 7 days, was designed. A positive response to the CCLT was considered to occur when urinary calcium (uCa) was > or = 4 mg/ kg/24 h on the 7th day. Among NCa patients, 29% of AH-like subjects responded to the CCLT and 71% did not; 50% of RH-like subjects also responded and 50% did not. In HCa patients, 85% of AH and 67% of RH subjects maintained uCa > or = 4 mg/kg/24 h after the CCLT and 15% of AH and 23% of RH subjects did not. However, a significant additional increase in mean uCa was not observed among HCa patients. All patients were submitted to a second evaluation of fasting calciuria (Ca/Cr). A modification of this parameter was noticed in 89% of RH-like and 78% of RH patients. In conclusion, these data suggest the presence of subpopulations of patients sensitive or not to calcium intake, regardless of whether the acute response to a calcium overload test suggested AH or RH. The CCLT disclosed dietary hypercalciuria in 21/58 (36%) of previously NCa patients. In these NCa patients, the ACLT may be replaced by the CCLT. The distinction

  16. Regulation of Cellular Calcium in Vestibular Supporting Cells by Otopetrin 1

    PubMed Central

    Kim, Euysoo; Hyrc, Krzysztof L.; Speck, Judith; Lundberg, Yunxia W.; Salles, Felipe T.; Kachar, Bechara; Goldberg, Mark P.; Warchol, Mark E.

    2010-01-01

    Otopetrin 1 (OTOP1) is a multitransmembrane domain protein, which is essential for mineralization of otoconia, the calcium carbonate biominerals required for vestibular function, and the normal sensation of gravity. The mechanism driving mineralization of otoconia is poorly understood, but it has been proposed that supporting cells and a mechanism to maintain high concentrations of calcium are critical. Using Otop1 knockout mice and a utricular epithelial organ culture system, we show that OTOP1 is expressed at the apex of supporting cells and functions to increase cytosolic calcium in response to purinergic agonists, such as adenosine 5′-triphosphate (ATP). This is achieved by blocking mobilization of calcium from intracellular stores in an extracellular calcium-dependent manner and by mediating influx of extracellular calcium. These data support a model in which OTOP1 acts as a sensor of the extracellular calcium concentration near supporting cells and responds to ATP in the endolymph to increase intracellular calcium levels during otoconia mineralization. PMID:20554841

  17. Sensor technology

    NASA Technical Reports Server (NTRS)

    Sokoloski, Martin M.

    1988-01-01

    The objective is to provide necessary expertise and technology to advance space remote sensing of terrestrial, planetary, and galactic phenomena through the use of electromagnetic and electro-optic properties of gas, liquid, and solid state materials technology. The Sensor Technology Program is divided into two subprograms: a base research and development part and a Civil Space Technology Initiative (CSTI) part. The base research and development consists of research on artificially grown materials such as quantum well and superlattice structure with the potential for new and efficient means for detecting electromagnetic phenomena. Research is also being done on materials and concepts for detector components and devices for measuring high energy phenomena such as UV, X-, and gamma rays that are required observables in astrophysis and solar physics missions. The CSTI program is more mission driven and is balanced among four major disciplines: detector sensors; submillimeter wave sensors; LIDAR/DIAL sensors; and cooler technology.

  18. Wireless sensor

    DOEpatents

    Lamberti, Vincent E.; Howell, JR, Layton N.; Mee, David K.; Sepaniak, Michael J.

    2016-02-09

    Disclosed is a sensor for detecting a target material. The sensor includes a ferromagnetic metal and a molecular recognition reagent coupled to the ferromagnetic metal. The molecular recognition reagent is operable to expand upon exposure to vapor or liquid from the target material such that the molecular recognition reagent changes a tensile stress upon the ferromagnetic metal. The target material is detected based on changes in the magnetic switching characteristics of the ferromagnetic metal caused by the changes in the tensile stress.

  19. Vibration sensors

    NASA Astrophysics Data System (ADS)

    Gupta, Amita; Singh, Ranvir; Ahmad, Amir; Kumar, Mahesh

    2003-10-01

    Today, vibration sensors with low and medium sensitivities are in great demand. Their applications include robotics, navigation, machine vibration monitoring, isolation of precision equipment & activation of safety systems e.g. airbags in automobiles. Vibration sensors have been developed at SSPL, using silicon micromachining to sense vibrations in a system in the 30 - 200 Hz frequency band. The sensing element in the silicon vibration sensor is a seismic mass suspended by thin silicon hinges mounted on a metallized glass plate forming a parallel plate capacitor. The movement of the seismic mass along the vertical axis is monitored to sense vibrations. This is obtained by measuring the change in capacitance. The movable plate of the parallel plate capacitor is formed by a block connected to a surrounding frame by four cantilever beams located on sides or corners of the seismic mass. This element is fabricated by silicon micromachining. Several sensors in the chip sizes 1.6 cm x 1.6 cm, 1 cm x 1 cm and 0.7 cm x 0.7 cm have been fabricated. Work done on these sensors, techniques used in processing and silicon to glass bonding are presented in the paper. Performance evaluation of these sensors is also discussed.

  20. Influence of dietary calcium on bone calcium utilization

    SciTech Connect

    Farmer, M.; Roland, D.A. Sr.; Clark, A.J.

    1986-02-01

    In Experiment 1, 10 microCi /sup 45/Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of /sup 45/Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and /sup 45/Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on /sup 45/Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and /sup 45/Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly.

  1. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    NASA Technical Reports Server (NTRS)

    Gooding, J. L.; Wentworth, S. J.

    1987-01-01

    Chips of glassy Lithology C of EETA79001 were studied by scanning electron microscopy and energy dispersive X-ray spectroscopy to determine the mineralogy and petrogenesis of the glass that was shown by others to contain trapped Mars-like gases. Calcium carbonite was identified as massive to acicular crystals for which Ca, C, and O were the major elements. Calcium sulfate was identified as prismatic-acicular crystals with Ca and S as the major elements.

  2. Prevalence, correlates and treatment of lifetime suicidal behavior among adolescents: Results from the National Comorbidity Survey Replication – Adolescent Supplement (NCS-A)

    PubMed Central

    Nock, Matthew K.; Green, Jennifer Greif; Hwang, Irving; McLaughlin, Katie A.; Sampson, Nancy A.; Zaslavsky, Alan M.; Kessler, Ronald C.

    2013-01-01

    Context Although suicide is the third leading cause of death among US adolescents, little is known about the prevalence, correlates, or treatment of its immediate precursors, adolescent suicidal behaviors (i.e., suicide ideation, plans, and attempts). Objectives To estimate lifetime prevalence of suicidal behaviors among US adolescents and associations of retrospectively-reported temporally primary DSM-IV disorders with the subsequent onset of suicidal behaviors. Design Dual-frame national sample of adolescents from the National Comorbidity Survey-Replication Adolescent Supplement (NCS-A). Setting Face-to-face household interviews with adolescents and questionnaires with parents. Participants 6,483 adolescents (ages 13–18 years) and parents. Main outcome measures Lifetime suicide ideation, plans, and attempts. Results The estimated lifetime prevalence of suicide ideation, plans, and attempts among NCS-A respondents is 12.1%, 4.0% and 4.1%. The vast majority of adolescents with these behaviors meet lifetime criteria for at least one DSM-IV mental disorder assessed in the survey. Most temporally primary (based on retrospective age-of-onset reports) fear/anger, distress, disruptive behavior, and substance disorders significantly predict elevated odds of subsequent suicidal behaviors in bivariate models. The most consistently significant associations of these disorders are with suicide ideation, although a number of disorders also predict plans and both planned and unplanned attempts among ideators. Most suicidal adolescents (>80%) receive some form of mental health treatment. In most cases (>55%) treatment starts prior to onset of suicidal behaviors but fails to prevent these behaviors from occurring. Conclusions Suicidal behaviors are commonly occurring among US adolescents, with rates that approach those of adults. The vast majority of youth with suicidal behaviors have pre-existing mental disorders. The disorders most powerfully predicting ideation, though, are

  3. Calcium signalling and calcium channels: evolution and general principles.

    PubMed

    Verkhratsky, Alexei; Parpura, Vladimir

    2014-09-15

    Calcium as a divalent cation was selected early in evolution as a signaling molecule to be used by both prokaryotes and eukaryotes. Its low cytosolic concentration likely reflects the initial concentration of this ion in the primordial soup/ocean as unicellular organisms were formed. As the concentration of calcium in the ocean subsequently increased, so did the diversity of homeostatic molecules handling calcium. This includes the plasma membrane channels that allowed the calcium entry, as well as extrusion mechanisms, i.e., exchangers and pumps. Further diversification occurred with the evolution of intracellular organelles, in particular the endoplasmic reticulum and mitochondria, which also contain channels, exchanger(s) and pumps to handle the homeostasis of calcium ions. Calcium signalling system, based around coordinated interactions of the above molecular entities, can be activated by the opening of voltage-gated channels, neurotransmitters, second messengers and/or mechanical stimulation, and as such is all-pervading pathway in physiology and pathophysiology of organisms. PMID:24291103

  4. Role of Calcium Signaling in B Cell Activation and Biology.

    PubMed

    Baba, Yoshihiro; Kurosaki, Tomohiro

    2016-01-01

    Increase in intracellular levels of calcium ions (Ca2+) is one of the key triggering signals for the development of B cell response to the antigen. The diverse Ca2+ signals finely controlled by multiple factors participate in the regulation of gene expression, B cell development, and effector functions. B cell receptor (BCR)-initiated Ca2+ mobilization is sourced from two pathways: one is the release of Ca2+ from the intracellular stores, endoplasmic reticulum (ER), and other is the prolonged influx of extracellular Ca2+ induced by depleting the stores via store-operated calcium entry (SOCE) and calcium release-activated calcium (CRAC) channels. The identification of stromal interaction molecule 1(STIM1), the ER Ca2+ sensor, and Orai1, a key subunit of the CRAC channel pore, has now provided the tools to understand the mode of Ca2+ influx regulation and physiological relevance. Herein, we discuss our current understanding of the molecular mechanisms underlying BCR-triggered Ca2+ signaling as well as its contribution to the B cell biological processes and diseases. PMID:26369772

  5. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactobionate. 172.720 Section 172.720 Food... Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... additive is the calcium salt of lactobionic acid (4-(β,D-galactosido)-D-gluconic acid) produced by...

  6. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  7. 21 CFR 184.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium hydroxide. 184.1205 Section 184.1205 Food... Specific Substances Affirmed as GRAS § 184.1205 Calcium hydroxide. (a) Calcium hydroxide (Ca(OH)2, CAS Reg. No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration...

  8. 21 CFR 184.1187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium alginate. 184.1187 Section 184.1187 Food... Specific Substances Affirmed as GRAS § 184.1187 Calcium alginate. (a) Calcium alginate (CAS Reg. No. 9005-35-0) is the calcium salt of alginic acid, a natural polyuronide constituent of certain brown...

  9. 21 CFR 172.715 - Calcium lignosulfonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lignosulfonate. 172.715 Section 172.715... CONSUMPTION Other Specific Usage Additives § 172.715 Calcium lignosulfonate. Calcium lignosulfonate may be safely used in or on food, subject to the provisions of this section. (a) Calcium lignosulfonate...

  10. 21 CFR 184.1199 - Calcium gluconate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... acid with lime or calcium carbonate. (b) The ingredient meets the specifications of the Food Chemicals... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium gluconate. 184.1199 Section 184.1199 Food... Specific Substances Affirmed as GRAS § 184.1199 Calcium gluconate. (a) Calcium gluconate ( 2Ca, CAS Reg....

  11. 21 CFR 172.410 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium silicate. 172.410 Section 172.410 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents § 172.410 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be...

  12. Calcium and Arrhythmogenesis

    PubMed Central

    Ter Keurs, Henk E. D. J.; Boyden, Penelope A.

    2010-01-01

    Triggered activity in cardiac muscle and intracellular Ca2+ have been linked in the past. However, today not only are there a number of cellular proteins that show clear Ca2+ dependence but also there are a number of arrhythmias whose mechanism appears to be linked to Ca2+-dependent processes. Thus we present a systematic review of the mechanisms of Ca2+ transport (forward excitation-contraction coupling) in the ventricular cell as well as what is known for other cardiac cell types. Second, we review the molecular nature of the proteins that are involved in this process as well as the functional consequences of both normal and abnormal Ca2+ cycling (e.g., Ca2+ waves). Finally, we review what we understand to be the role of Ca2+ cycling in various forms of arrhythmias, that is, those associated with inherited mutations and those that are acquired and resulting from reentrant excitation and/or abnormal impulse generation (e.g., triggered activity). Further solving the nature of these intricate and dynamic interactions promises to be an important area of research for a better recognition and understanding of the nature of Ca2+ and arrhythmias. Our solutions will provide a more complete understanding of the molecular basis for the targeted control of cellular calcium in the treatment and prevention of such. PMID:17429038

  13. Calcium transport in turtle bladder

    SciTech Connect

    Sabatini, S.; Kurtzman, N.A. )

    1987-12-01

    Unidirectional {sup 45}Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (J{sup net}{sub Ca}) was secretory (serosa to mucosa). Ouabain reversed J{sup net}{sub Ca} to an absorptive flux. Amiloride reduced both fluxes such that J{sup net}{sub Ca} was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, J{sup net}{sub Ca} decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J{sup net}{sub Ca} was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue {sup 45}Ca content was {approx equal}30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca{sup 2+}-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na{sup +}-K{sup +}-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa.

  14. Medical therapy, calcium oxalate urolithiasis

    NASA Technical Reports Server (NTRS)

    Ruml, L. A.; Pearle, M. S.; Pak, C. Y.

    1997-01-01

    The development of diagnostic protocols that identify specific risk factors for calcium oxalate nephrolithiasis has led to the formulation of directed medical regimens that are aimed at correcting the underlying metabolic disturbances. Initiation of these treatment programs has reduced markedly the rate of stone formation in the majority of patients who form stones. This article discusses the rationale that underlies the choice of medical therapy for the various pathophysiologic causes of calcium oxalate nephrolithiasis and the appropriate use of available medications.

  15. Research sensors

    NASA Astrophysics Data System (ADS)

    Englund, David R.

    1988-05-01

    The work described is part of a program (Englund and Seasholtz, 1988) to develop sensors and sensing techniques for research applications on aircraft turbine engines. In general, the sensors are used to measure the environment at a given location within a turbine engine or to measure the response of an engine component to the imposed environment. Locations of concern are generally in the gas path and, for the most part, are within the hot section. Specific parameters of concern are dynamic gas temperature, heat flux, airfoil surface temperature, and strain on airfoils and combustor liners. To minimize the intrusiveness of surface-mounted sensors, a considerable effort was expended to develop thin-film sensors for surface temperature, strain, and heat flux measurements. In addition, an optical system for viewing the interior of an operating combustor was developed. Most of the work described is sufficiently advanced that the sensors were used and useful data were obtained. The notable exception is the work to develop a high-temperature static strain measuring capability; the work is still in progress.

  16. Crystal growth and characterization of a novel inorganic-organic hybrid NLO crystal: (NH4)[Cd(NCS)3]·C12H24O6

    NASA Astrophysics Data System (ADS)

    Ramesh, V.; Rajarajan, K.

    2013-10-01

    It is reported here, for the first time, that high-quality bulk size (18 × 5 × 4 mm3) single crystals of a new nonlinear optical crystal, [(NH4)[Cd(NCS)3]·C12H24O6] [Ammonium (18-crown-6-ether) Cadmium(II) tri-thiocyanate; ACCTC], have been grown from aqueous solution via slow evaporation technique. Solubility of ACCTC has been determined for various temperatures. The grown crystals were characterized by single crystal X-ray diffraction, FT-IR, FT-Raman, and UV-Vis-NIR studies. ACCTC crystallizes in orthorhombic system with cell parameters a = 14.7568 Ǻ, b = 15.4378 Ǻ, and c = 10.6383 Ǻ with space group Cmc21. The optical second-harmonic generation effect has been measured by using the Kurtz powder technique and is found to be 2 times higher than that of KDP (KH2PO4). The sample possesses wide optical transparency range from 200 to 2,500 nm. The TG-DSC thermal analysis revealed that the sample is thermally stable up to 237.92 °C, which is comparatively far better than the thermal stability of [(18C6)Li][Cd(SCN)3]; CLTC (170 °C).

  17. A fourth polymorph in the family of BEDT-TTF salts with thiocyanatocuprate(I) anions: (BEDT-TTF){<_4}Cu{<_3}(NCS){<_5}.

    SciTech Connect

    Schlueter, J. A.; Geiser, U.; Wang, H. H.; Manson, J. L.

    2012-05-01

    A new crystallographic modification was found in the family of BEDT-TTF salts containing thiocyanatocuprate(I) anions. The cation radical salt crystallizes in the P{sup {bar 1}} space group with a = 8.2720(9) {angstrom}, b = 19.099(2) {angstrom}, c = 43.758(5) {angstrom}, {alpha} = 81.088(4){sup o}, {beta} = 87.253(4){sup o}, {gamma} = 83.790(4){sup o}, V = 6786.2(13) {angstrom}{sup 3} at 150 K. The BEDT-TTF radical cations pack in an {alpha}-type motif, but every four columns, there is a slip in the layer. Where this slip occurs, the stacks are coupled in a {beta}'' manner. The material exhibits semiconductive behavior with an activation energy of 0.13 eV above 250 K and 0.22 eV below. Packing motif of the (BEDT-TTF){sub 4}Cu{sub 3}(NCS){sub 5} structure.

  18. Synthesis of Nanocrystals and Particle Size Effects Studies on the Thermally Induced Spin Transition of the Model Spin Crossover Compound [Fe(phen)2(NCS)2].

    PubMed

    Valverde-Muñoz, Francisco Javier; Gaspar, Ana B; Shylin, Sergii I; Ksenofontov, Vadim; Real, José A

    2015-08-17

    Surfactant-free nanocrystals of the model spin-crossover compound [Fe(phen)2(NCS)2] (phen: 1,10-phenanthroline) have been synthesized applying the reverse micelle technique. The morphology of the nanocrystals, characterized by scanning electronic microscopy, corresponds to rhombohedric platelets with dimensions ranging from 203 × 203 × 106 nm to 142 × 142 × 74 nm. Variation of the concentration of the Fe(BF4)2·6H2O salt in the synthesis has been found to have little influence on the crystallite size. In contrast, the solvent-surfactant ratio (ω) is critical for a good particle growth. The spin transition of the nanocrystals has been characterized by magnetic susceptibility measurements and Mössbauer spectroscopy. The nanocrystals undergo an abrupt and more cooperative spin transition in comparison with the bulk compound. The spin transition is centered in the interval of temperature of 175-185 K and is accompanied by 8 K of thermal hysteresis width. The crystallite quality more than the crystallite size is responsible for the higher cooperativity. The magnetic properties of the nanocrystals embedded in organic polymers such as polyethylene glycol, nujol, glycerol, and triton have been studied as well. The spin transition in the nanocrystals is affected by the polymer coating. The abrupt and first-order spin transition transforms into a more continuous spin transition as a result of the chemical pressure asserted by the organic polymers on the Fe(II) centers. PMID:26208031

  19. S=½ Ising Behavior in the Two-dimensional Molecular Magnet Fe(NCS)2(pyrazine)2

    SciTech Connect

    Bordallo, H. N.; Chapon, L. C.; Manson, Jamie L; Hernandez-Velasco, J.; Ravot, D.; Reiff, W. M.; Argyriou, D. N.

    2004-01-01

    The magnetic ordering and critical behavior of antiferromagnetic Fe(NCS){sub 2}(pyrazine){sub 2} has been studied by neutron powder diffraction (NPD), inelastic neutron scattering (INS), Moessbauer spectroscopy, and magnetic measurements. The system can be regarded as a two-dimensional (2D) antiferromagnet even in the ordered phase, given that long-range magnetic ordering between the layers simply follows a necessary consequence of the establishment of long-range ordering within the planes. The INS data, which were taken on a cold neutron time-of-flight spectrometer, reveals that when the temperature is lowered towards T{sub N}, the correlation length within the 2D layers increases and ultimately crosses over from two- to three-dimensional (3D) behavior. Indeed, 3D long-range antiferromagnetic order, associated with a propagation vector [1,0,1/4+{epsilon}], is observed in the NPD data below 6.8 K. Furthermore, in agreement with the behavior of both {chi}(T) and C{sub m}(T) data, the order parameter follows the exact Osanger solution for a 2D S = 1/2, Ising system.

  20. Reliability and storage capacity: a compromise illustrated in the two-step spin-crossover system [Fe(bapbpy)(NCS)(2)].

    PubMed

    Kepenekian, Mikael; Costa, José Sánchez; Le Guennic, Boris; Maldivi, Pascale; Bonnet, Sylvestre; Reedijk, Jan; Gamez, Patrick; Robert, Vincent

    2010-12-01

    The design of bistable magnetic systems should enable the storage of information by manipulation of the spin degrees of freedom. However, such a strategy relies on the preparation of target objects, whose environment must be controlled to favor a hysteretic behavior. Here, we report the successful modeling of a highly cooperative two-step spin-crossover iron(II) compound, [Fe(bapbpy)(NCS)(2)]. The magnetic susceptibility measurements and low- and high-temperature hysteretic cycles reflect the presence of an intermediate phase, which controls the memory-storage capacity of this material. It is shown that the hysteresis loop widths can be traced theoretically by evaluating the electrostatic contributions between the transiting units. Despite the apparent reduction of intermolecular interactions upon cooling, it is suggested that the enhanced fluctuations of the Madelung field are responsible for the observed hysteresis width changes. This counterintuitive scenario makes the preparation of information storage devices an even more challenging task, where theoretical inspections are very insightful. PMID:20973484

  1. Optimum calcination temperature in the synthesis of a N-C-S co-doped TiO2 photocatalyst, as monitored by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Rozas, Francisco; Bengtsson, Nicklas; Fabelo, Oscar; Puente, Inés; Castellote, Marta

    2014-11-01

    Calcination of a co-doped (N-C-S) TiO2 photocatalyst has been done following the whole process by neutron diffraction (instrument D1B of the ILL) with the objective of study the transition between two crystalline phases: anatase and rutile in order to find the optimum temperature leading to the coexistence of both for this catalyst whose band gap has been shifted to give activity in the visible part of the electromagnetic spectrum. This coexistence is important as it has been established that these catalyst are more efficient than those having only one individual phase. At this respect, it is very important to find the optimum temperature at with synthesis has to be done. In this research it was established that at the heating ramp of 17°C/5 min, the coexistence of both crystalline phases took place within a narrow margin of temperatures between 610°C and 690°C. At higher temperatures only rutile can be identified as the crystalline phase of the TiO2.

  2. The calcium-alkali syndrome.

    PubMed

    Arroyo, Mariangeli; Fenves, Andrew Z; Emmett, Michael

    2013-04-01

    The milk-alkali syndrome was a common cause of hypercalcemia, metabolic alkalosis, and renal failure in the early 20th century. It was caused by the ingestion of large quantities of milk and absorbable alkali to treat peptic ulcer disease. The syndrome virtually vanished after introduction of histamine-2 blockers and proton pump inhibitors. More recently, a similar condition called the calcium-alkali syndrome has emerged as a common cause of hypercalcemia and alkalosis. It is usually caused by the ingestion of large amounts of calcium carbonate salts to prevent or treat osteoporosis and dyspepsia. We describe a 78-year-old woman who presented with weakness, malaise, and confusion. She was found to have hypercalcemia, acute renal failure, and metabolic alkalosis. Upon further questioning, she reported use of large amounts of calcium carbonate tablets to treat recent heartburn symptoms. Calcium supplements were discontinued, and she was treated with intravenous normal saline. After 5 days, the calcium and bicarbonate levels normalized and renal function returned to baseline. In this article, we review the pathogenesis of the calcium-alkali syndrome as well as the differences between the traditional and modern syndromes. PMID:23543983

  3. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  4. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications...

  5. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium lactate. 184.1207 Section 184.1207 Food and... Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any... calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of the Food...

  6. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... Specific Substances Affirmed as GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O,...

  7. Water Sensors

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Mike Morris, former Associate Director of STAC, formed pHish Doctor, Inc. to develop and sell a pH monitor for home aquariums. The monitor, or pHish Doctor, consists of a sensor strip and color chart that continually measures pH levels in an aquarium. This is important because when the level gets too high, ammonia excreted by fish is highly toxic; at low pH, bacteria that normally break down waste products stop functioning. Sales have run into the tens of thousands of dollars. A NASA Tech Brief Technical Support Package later led to a salt water version of the system and a DoE Small Business Innovation Research (SBIR) grant for development of a sensor for sea buoys. The company, now known as Ocean Optics, Inc., is currently studying the effects of carbon dioxide buildup as well as exploring other commercial applications for the fiber optic sensor.

  8. Calcium metabolism and cardiovascular function after spaceflight

    NASA Technical Reports Server (NTRS)

    Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric; Orwoll, Shiela; McCarron, David A.

    2002-01-01

    To determine the influence of dietary calcium on spaceflight-induced alterations in calcium metabolism and blood pressure (BP), 9-wk-old spontaneously hypertensive rats, fed either high- (2%) or low-calcium (0.02%) diets, were flown on an 18-day shuttle flight. On landing, flight animals had increased ionized calcium (P < 0.001), elevated parathyroid hormone levels (P < 0.001), reduced calcitonin levels (P < 0.05), unchanged 1,25(OH)(2)D(3) levels, and elevated skull (P < 0.01) and reduced femur bone mineral density. Basal and thrombin-stimulated platelet free calcium (intracellular calcium concentration) were also reduced (P < 0.05). There was a tendency for indirect systolic BP to be reduced in conscious flight animals (P = 0.057). However, mean arterial pressure was elevated (P < 0.001) after anesthesia. Dietary calcium altered all aspects of calcium metabolism (P < 0.001), as well as BP (P < 0.001), but the only interaction with flight was a relatively greater increase in ionized calcium in flight animals fed low- compared with high-calcium diets (P < 0.05). The results indicate that 1) flight-induced disruptions of calcium metabolism are relatively impervious to dietary calcium in the short term, 2) increased ionized calcium did not normalize low-calcium-induced elevations of BP, and 3) parathyroid hormone was paradoxically increased in the high-calcium-fed flight animals after landing.

  9. Microcantilever sensors

    SciTech Connect

    Thundat, T.; Warmack, R.J.; Oden, P.I. |; Dasktos, P.G.; Chen, G.Y. |

    1996-04-01

    Novel sensors based on bending and resonance frequency changes of (coated silicon) microcantilevers are discussed. Adsorption-induced resonance frequency changes of microcantilevers can be due to a combination of mass loading and change of spring constant resulting from adsorption of chemicals on the surface. Cantilevers also undergo static bending due to adsorption-induced differential surface stress if the adsorption is confined to one surface. Hence cantilever deflection as well as resonance frequency change can be used as the basis for development of novel chemcal sensors.

  10. Calcium signaling and cytotoxicity.

    PubMed Central

    Kass, G E; Orrenius, S

    1999-01-01

    The divalent calcium cation Ca(2+) is used as a major signaling molecule during cell signal transduction to regulate energy output, cellular metabolism, and phenotype. The basis to the signaling role of Ca(2+) is an intricate network of cellular channels and transporters that allow a low resting concentration of Ca(2+) in the cytosol of the cell ([Ca(2+)]i) but that are also coupled to major dynamic and rapidly exchanging stores. This enables extracellular signals from hormones and growth factors to be transduced as [Ca(2+)]i spikes that are amplitude and frequency encoded. There is considerable evidence that a number of toxic environmental chemicals target these Ca(2+) signaling processes, alter them, and induce cell death by apoptosis. Two major pathways for apoptosis will be considered. The first one involves Ca(2+)-mediated expression of ligands that bind to and activate death receptors such as CD95 (Fas, APO-1). In the second pathway, Ca(2+) has a direct toxic effect and its primary targets include the mitochondria and the endoplasmic reticulum (ER). Mitochondria may respond to an apoptotic Ca(2+) signal by the selective release of cytochrome c or through enhanced production of reactive oxygen species and opening of an inner mitochondrial membrane pore. Toxic agents such as the environmental pollutant tributyltin or the natural plant product thapsigargin, which deplete the ER Ca(2+) stores, will induce as a direct result of this effect the opening of plasma membrane Ca(2+) channels and an ER stress response. In contrast, under some conditions, Ca(2+) signals may be cytoprotective and antagonize the apoptotic machinery. Images Figure 1 Figure 2 Figure 3 PMID:10229704

  11. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical ...

  12. Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

    SciTech Connect

    Nehm, F. Müller-Meskamp, L.; Klumbies, H.; Leo, K.

    2015-12-15

    A major failure mechanism is identified in electrical calcium corrosion tests for quality assessment of high-end application moisture barriers. Accelerated calcium corrosion is found at the calcium/electrode junction, leading to an electrical bottleneck. This causes test failure not related to overall calcium loss. The likely cause is a difference in electrochemical potential between the aluminum electrodes and the calcium sensor, resulting in a corrosion element. As a solution, a thin, full-area copper layer is introduced below the calcium, shifting the corrosion element to the calcium/copper junction and inhibiting bottleneck degradation. Using the copper layer improves the level of sensitivity for the water vapor transmission rate (WVTR) by over one order of magnitude. Thin-film encapsulated samples with 20 nm of atomic layer deposited alumina barriers this way exhibit WVTRs of 6 × 10{sup −5} g(H{sub 2}O)/m{sup 2}/d at 38 °C, 90% relative humidity.

  13. Gas sensor

    DOEpatents

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  14. Chemical sensors

    DOEpatents

    Lowell, Jr., James R.; Edlund, David J.; Friesen, Dwayne T.; Rayfield, George W.

    1991-01-01

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising (a) a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, operatively coupled to (b) a transducer capable of directly converting said expansion or contraction to a measurable electrical response.

  15. Chemical sensor

    NASA Technical Reports Server (NTRS)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  16. Sensor apparatus

    DOEpatents

    Deason, Vance A [Idaho Falls, ID; Telschow, Kenneth L [Idaho Falls, ID

    2009-12-22

    A sensor apparatus and method for detecting an environmental factor is shown that includes an acoustic device that has a characteristic resonant vibrational frequency and mode pattern when exposed to a source of acoustic energy and, futher, when exposed to an environmental factor, produces a different resonant vibrational frequency and/or mode pattern when exposed to the same source of acoustic energy.

  17. Aging and calcium as an environmental factor.

    PubMed

    Fujita, T

    1985-12-01

    Calcium deficiency is a constant menace to land-abiding animals, including mammals. Humans enjoying exceptional longevity on earth are especially susceptible to calcium deficiency in old age. Low calcium and vitamin D intake, short solar exposure, decreased intestinal absorption, and falling renal function with insufficient 1,25(OH)2 vitamin D biosynthesis all contribute to calcium deficiency, secondary hyperparathyroidism, bone loss and possibly calcium shift from the bone to soft tissue, and from the extracellular to the intracellular compartment, blunting the sharp concentration gap between these compartments. The consequences of calcium deficiency might thus include not only osteoporosis, but also arteriosclerosis and hypertension due to the increase of calcium in the vascular wall, amyotrophic lateral sclerosis and senile dementia due to calcium deposition in the central nervous system, and a decrease in cellular function, because of blunting of the difference in extracellular-intracellular calcium, leading to diabetes mellitus, immune deficiency and others (Fig. 6). PMID:2943880

  18. Transport of Calcium Ions into Mitochondria.

    PubMed

    Xu, Zhaolong; Zhang, Dayong; He, Xiaolan; Huang, Yihong; Shao, Hongbo

    2016-06-01

    To uptake calcium ions of mitochondria is of significant functional connotation for cells, because calcium ions in mitochondria are involved in energy production, regulatory signals transfer, and mitochondrial permeability transition pore opening and even programmed cell death of apoptosis, further playing more roles in plant productivity and quality. Cytoplasmic calcium ions access into outer mitochondrial membrane (OMM) from voltage dependent anion-selective channel (VDAC) and were absorbed into inner mitochondrial membrane (IMM) by mitochondrial calcium uniporter (MCU), rapid mitochondrial calcium uptake (RaM) or mitochondrial ryanodine receptor (mRyR). Although both mitochondria and the mechanisms of calcium transport have been extensively studied, but there are still long-standing or even new challenges. Here we review the history and recent discoveries of the mitochondria calcium ions channel complex involved calcium assimilation, and discuss the role of calcium ions into mitochondria. PMID:27252588

  19. STIM1 Protein Activates Store-Operated Calcium Channels in Cellular Model of Huntington’s Disease

    PubMed Central

    Vigont, V. A.; Zimina, O. A.; Glushankova, L. N.; Kolobkova, J. A.; Ryazantseva, M. A.; Mozhayeva, G. N.; Kaznacheyeva, E. V.

    2014-01-01

    We have shown that the expression of full-length mutated huntingtin in human neuroblastoma cells (SK-N-SH) leads to an abnormal increase in calcium entry through store-operated channels. In this paper, the expression of the N-terminal fragment of mutated huntingtin (Htt138Q-1exon) is shown to be enough to provide an actual model for Huntington’s disease. We have shown that Htt138Q-1exon expression causes increased store-operated calcium entry, which is mediated by at least two types of channels in SK-N-SH cells with different reversal potentials. Calcium sensor, STIM1, is required for activation of store-operated calcium entry in these cells. The results provide grounds for considering the proteins responsible for the activation and maintenance of the store-operated calcium entry as promising targets for developing novel therapeutics for neurodegenerative diseases. PMID:25558393

  20. Calcium supplement: humanity's double-edged sword.

    PubMed

    Bunyaratavej, Narong; Buranasinsup, Shutipen

    2011-10-01

    The principle aim of the present study is to investigate the dark side of calcium, pollutions in calcium preparation especially lead (Pb), mercury (Hg) and cadmium (Cd). The collected samples were the different calcium salts in the market and 18 preparations which were classified into 3 groups: Calcium carbonate salts, Chelated calcium and natural-raw calcium. All samples were analyzed for lead, cadmium and mercury by inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique, in house method based on AOAC (2005) 999.10 by ICP-MS. The calcium carbonate and the natural-raw calcium in every sample contained lead at 0.023-0.407 mg/kg of calcium powder. Meanwhile, the natural-raw calcium such as oyster, coral and animal bone showed amount of lead at 0.106-0.384 mg/kg with small amounts of mercury and cadmium. The chelated calcium such as calcium gluconate, calcium lactate and calcium citrate are free of lead. PMID:22338928

  1. Optimizing calcium selective fluorimetric nanospheres.

    PubMed

    Kisiel, Anna; Kłucińska, Katarzyna; Gniadek, Marianna; Maksymiuk, Krzysztof; Michalska, Agata

    2015-11-01

    Recently it was shown that optical nanosensors based on alternating polymers e.g. poly(maleic anhydride-alt-1-octadecene) were characterized by a linear dependence of emission intensity on logarithm of concentration over a few of orders of magnitude range. In this work we focus on the material used to prepare calcium selective nanosensors. It is shown that alternating polymer nanosensors offer competitive performance in the absence of calcium ionophore, due to interaction of the nanospheres building blocks with analyte ions. The emission increase corresponds to increase of calcium ions contents in the sample within the range from 10(-4) to 10(-1) M. Further improvement in sensitivity (from 10(-6) to 10(-1) M) and selectivity can be achieved by incorporating calcium ionophore in the nanospheres. The optimal results were obtained for core-shell nanospheres, where the core was prepared from poly(styrene-co-maleic anhydride) and the outer layer from poly(maleic anhydride-alt-1-octadecene). Thus obtained chemosensors were showing linear dependence of emission on logarithm of calcium ions concentration within the range from 10(-7) to 10(-1) M. PMID:26452839

  2. Two-step spin crossover in the mononuclear iron(II) complex [Fe(II)(L)(2)(NCS)(2)] (L = 2,5-di-(2-pyridyl)-1,3,4-thiadiazole).

    PubMed

    Klingele, Julia; Kaase, Dominik; Klingele, Marco H; Lach, Jochen; Demeshko, Serhiy

    2010-02-21

    The first iron(ii) complex of 2,5-di-(2-pyridyl)-1,3,4-thiadiazole (L), namely [Fe(II)(L)(2)(NCS)(2)], has been synthesised and studied by magnetic susceptibility measurements, Mössbauer spectroscopy and X-ray diffraction. It has been found to undergo thermally-induced spin crossover featuring two well-separated, abrupt steps at T(1/2)(1) = 167 K and T(1/2)(2) = 112 K. PMID:20449403

  3. Synthesis of hexa aza cages, SarAr-NCS and AmBaSar and a study of their metal complexation, conjugation to nanomaterials and proteins for application in radioimaging and therapy.

    PubMed

    Mume, Eskender; Asad, Ali; Di Bartolo, Nadine M; Kong, Linggen; Smith, Christopher; Sargeson, Alan M; Price, Roger; Smith, Suzanne V

    2013-10-28

    A novel hexa aza cage, N(1)-(4-isothiocyanatobenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane-1,8-diamine (SarAr-NCS) was synthesized in good yield and characterized by (1)H NMR and electrospray mass spectrometry. A new method for the synthesis of the related N(1)-(4-carboxybenzyl)-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane-1,8-diamine (AmBaSar) using the p-carboxybenzaldehyde is reported. The complexation of Cu(2+), Co(2+) and Zn(2+) by the two ligands over a range of pHs was found to be similar to the parent derivative SarAr. SarAr-NCS was conjugated to both silica particles (≈90 nm diam.) and the model B72.3 murine antibody. The SarAr-NCSN-silica particles were radiolabeled with Cu(2+) doped (64)Cu and the number of ligands conjugated was calculated to be an average of 7020 ligands per particle. Conjugation of SarAr-NCS to the B72.3 antibody was optimized over a range of conditions. The SarAr-NCSN-B72.3 conjugate was stored in buffer and as a lyophilized powder at 4 °C over 38 days. Its radiolabeling efficiency, stability and immunoreactivity were maintained. The development of a high yielding synthesis of SarAr-NCS should provide an entry point for a wide range of Cu and Zn radiometal PET imaging agents and potentially radiotherapeutic agents with (67)Cu. PMID:23851350

  4. Determining crystal growth kinetic parameters using optical fibre sensors

    NASA Astrophysics Data System (ADS)

    Boerkamp, M.; Lamb, D. W.; Lye, P. G.

    2012-12-01

    The capability of an 'intrinsic exposed core optical fibre sensor' (IECOFS) as a monitoring device of scale formation has been evaluated. The IECOFS has been used to measure kinetics parameters of calcium carbonate heterogeneous crystal growth such as the activation energy, the crystal growth rate and the induction time. The IECOFS was able to evaluate crystal growth inhibition through the use of chemical inhibitors.

  5. Exploring the associations between microRNA expression profiles and environmental pollutants in human placenta from the National Children's Study (NCS)

    PubMed Central

    Li, Qian; Kappil, Maya A; Li, An; Dassanayake, Priyanthi S; Darrah, Thomas H; Friedman, Alan E; Friedman, Michelle; Lambertini, Luca; Landrigan, Philip; Stodgell, Christopher J; Xia, Yulin; Nanes, Jessica A; Aagaard, Kjersti M; Schadt, Eric E; Murray, Jeff C; Clark, Edward B; Dole, Nancy; Culhane, Jennifer; Swanson, James; Varner, Michael; Moye, Jack; Kasten, Carol; Miller, Richard K; Chen, Jia

    2015-01-01

    The placenta is the principal regulator of the in utero environment, and disruptions to this environment can result in adverse offspring health outcomes. To better characterize the impact of in utero perturbations, we assessed the influence of known environmental pollutants on the expression of microRNA (miRNA) in placental samples collected from the National Children's Study (NCS) Vanguard birth cohort. This study analyzed the expression of 654 miRNAs in 110 term placentas. Environmental pollutants measured in these placentas included dichlorodiphenyldichloroethylene (DDE), bisphenol A (BPA), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), arsenic (As), mercury (Hg), lead (Pb), and cadmium (Cd). A moderated t-test was used to identify a panel of differentially expressed miRNAs, which were further analyzed using generalized linear models. We observed 112 miRNAs consistently expressed in >70% of the samples. Consistent with the literature, miRNAs located within the imprinted placenta-specific C19MC cluster, specifically mir-517a, mir-517c, mir-522, and mir-23a, are among the top expressed miRNA in our study. We observed a positive association between PBDE 209 and miR-188–5p and an inverse association between PBDE 99 and let-7c. Both PCBs and Cd were positively associated with miR-1537 expression level. In addition, multiple let-7 family members were downregulated with increasing levels of Hg and Pb. We did not observe DDE or BPA levels to be associated with placental miRNA expression. This is the first birth cohort study linking environmental pollutants and placental expression of miRNAs. Our results suggest that placental miRNA profiles may signal in utero exposures to environmental chemicals. PMID:26252056

  6. Service Utilization for Lifetime Mental Disorders in U.S. Adolescents: Results of the National Comorbidity Survey Adolescent Supplement (NCS-A)

    PubMed Central

    Merikangas, Kathleen Ries; He, Jian-ping; Burstein, Marcy E.; Swendsen, Joel; Avenevoli, Shelli; Case, Brady; Georgiades, Katholiki; Heaton, Leanne; Swanson, Sonja; Olfson, Mark

    2013-01-01

    Objective Mental health policy for youth has been constrained by a paucity of nationally representative data concerning patterns and correlates of mental health service utilization in this segment of the population. The objectives of this investigation are to examine the rates and sociodemographic correlates of lifetime mental health service use by severity, type, and number of DSM-IV disorders in the National Comorbidity Survey-Adolescent Supplement (NCS-A). Method Face-to-face survey of mental disorders from 2002-2004 using a modified version of the fully-structured World Health Organization Composite International Diagnostic Interview in a nationally representative sample of 6,483 adolescents aged 13-18 years for whom information on service use was available from both an adolescent and a parent report. Both total and sector-specific mental health service use was also assessed. Results Approximately one-third of adolescents with mental disorders received services for their illness (36.2%). Although disorder severity was significantly associated with an increased likelihood of receiving treatment, half of adolescents with severely impairing mental disorders had never received mental health treatment for their symptoms. Service rates were highest among those with attention-deficit/hyperactivity disorder (59.8%) and behavior disorders (45.4%), but less than one in five affected adolescents received services for anxiety, eating, or substance use disorders. Comorbidity and severe impairment were strongly associated with service utilization, particularly among youth with behavior disorders. Hispanic and non-Hispanic black adolescents were less likely than their white counterparts to receive services for mood and anxiety disorders, even when such disorders were associated with severe impairment. Conclusions Despite advances in public awareness of mental disorders in youth, a substantial proportion of young people with severe mental disorders have never received

  7. The Prevalence and Correlates of Lifetime Psychiatric Disorders and Trauma Exposures in Urban and Rural Settings: Results from the National Comorbidity Survey Replication (NCS-R)

    PubMed Central

    McCall-Hosenfeld, Jennifer S.; Mukherjee, Sucharita; Lehman, Erik B.

    2014-01-01

    Introduction Distinctions between rural and urban environments produce different frequencies of traumatic exposures and psychiatric disorders. We examine the prevalence of psychiatric disorders and frequency of trauma exposures by position on the rural-urban continuum. Methods The National Comorbidity Survey Replication (NCS-R) was used to evaluate psychiatric disorders among a nationally-representative sample of the U.S. population. Rurality was designated using the Department of Agriculture's 2003 rural-urban continuum codes (RUCC), which differentiate counties into levels of rurality by population density and adjacency to metropolitan areas. Lifetime psychiatric disorders included post-traumatic stress disorder (PTSD), anxiety disorders, major depressive disorder, mood disorders, impulse-control disorders, and substance abuse. Trauma exposures were classified as war-related, accident-related, disaster-related, interpersonal or other. Weighted logistic regression models examined the odds of psychiatric disorders and trauma exposures by position on the rural-urban continuum, adjusted for relevant covariates. Results 75% of participants were metropolitan, 12.2% were suburban, and 12.8% were from rural counties. The most common disorder reported was any anxiety disorder (38.5%). Drug abuse was more common among metropolitan (8.7%, p = 0.018), compared to nonmetropolitan (5.1% suburban, 6.1% rural) participants. A one-category increase in rurality was associated with decreased odds for war-related trauma (aOR = 0.86, 95%CI 0.78–0.95). Rurality was not associated with risk for any other lifetime psychiatric disorders or trauma exposure. Discussion/Conclusions Contrary to the expectation of some rural primary care providers, the frequencies of most psychiatric disorders and trauma exposures are similar across the rural-urban continuum, reinforcing calls to improve mental healthcare access in resource-poor rural communities. PMID:25380277

  8. Calcium release-activated calcium current in rat mast cells.

    PubMed

    Hoth, M; Penner, R

    1993-06-01

    1. Whole-cell patch clamp recordings of membrane currents and fura-2 measurements of free intracellular calcium concentration ([Ca2+]i) were used to study the biophysical properties of a calcium current activated by depletion of intracellular calcium stores in rat peritoneal mast cells. 2. Calcium influx through an inward calcium release-activated calcium current (ICRAC) was induced by three independent mechanisms that result in store depletion: intracellular infusion of inositol 1,4,5-trisphosphate (InsP3) or extracellular application of ionomycin (active depletion), and intracellular infusion of calcium chelators (ethylene glycol bis-N,N,N',N'-tetraacetic acid (EGTA) or 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)) to prevent reuptake of leaked-out calcium into the stores (passive depletion). 3. The activation of ICRAC induced by active store depletion has a short delay (4-14 s) following intracellular infusion of InsP3 or extracellular application of ionomycin. It has a monoexponential time course with a time constant of 20-30 s and, depending on the complementary Ca2+ buffer, a mean normalized amplitude (at 0 mV) of 0.6 pA pF-1 (with EGTA) and 1.1 pA pF-1 (with BAPTA). 4. After full activation of ICRAC by InsP3 in the presence of EGTA (10 mM), hyperpolarizing pulses to -100 mV induced an instantaneous inward current that decayed by 64% within 50 ms. This inactivation is probably mediated by [Ca2+]i, since the decrease of inward current in the presence of the fast Ca2+ buffer BAPTA (10 mM) was only 30%. 5. The amplitude of ICRAC was dependent on the extracellular Ca2+ concentration with an apparent dissociation constant (KD) of 3.3 mM. Inward currents were nonsaturating up to -200 mV. 6. The selectivity of ICRAC for Ca2+ was assessed by using fura-2 as the dominant intracellular buffer (at a concentration of 2 mM) and relating the absolute changes in the calcium-sensitive fluorescence (390 nm excitation) with the calcium current integral

  9. Calcium phosphate in catheter encrustation.

    PubMed

    Cox, A J; Harries, J E; Hukins, D W; Kennedy, A P; Sutton, T M

    1987-02-01

    Encrusted catheters from nine female patients were the source of samples of deposits which were examined by X-ray diffraction, atomic absorption spectroscopy, infra-red spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. In eight samples the only crystalline phase which could be clearly distinguished by X-ray diffraction was ammonium magnesium orthophosphate hexahydrate, NH4MgPO4 X 6H2O, which occurs naturally as the mineral struvite. However, atomic absorption spectroscopy revealed an appreciable concentration of calcium in all samples. Calcium phosphates have previously been detected in catheter deposits. Infra-red and EXAFS spectra were consistent with the calcium phosphate being present as a poorly crystalline hydroxyapatite. Thus the deposits appear to consist of a mixture of crystalline struvite and a form of hydroxyapatite which is not fully crystalline. PMID:3030487

  10. The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Chu, J.

    1971-01-01

    The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

  11. Detection of high-energy compounds using photoluminescent silicon nanocrystal paper based sensors

    NASA Astrophysics Data System (ADS)

    Gonzalez, Christina M.; Iqbal, Muhammad; Dasog, Mita; Piercey, Davin G.; Lockwood, Ross; Klapötke, Thomas M.; Veinot, Jonathan G. C.

    2014-02-01

    Luminescent silicon nanocrystals (Si-NCs) surface functionalized with dodecyl groups were exposed to solutions of nitroaromatic compounds including nitrobenzene, nitrotoluene, and dinitrotoluene. It was found that Si-NC luminescence was quenched upon exposure to nitroaromatics via an electron transfer mechanism as indicated by Stern-Volmer analysis. This quenching was exploited and a straightforward paper-based Si-NC sensor was developed. This paper motif was found to be sensitive to solution, vapor, and solid phase nitroaromatics, as well as solution borne RDX and PETN.Luminescent silicon nanocrystals (Si-NCs) surface functionalized with dodecyl groups were exposed to solutions of nitroaromatic compounds including nitrobenzene, nitrotoluene, and dinitrotoluene. It was found that Si-NC luminescence was quenched upon exposure to nitroaromatics via an electron transfer mechanism as indicated by Stern-Volmer analysis. This quenching was exploited and a straightforward paper-based Si-NC sensor was developed. This paper motif was found to be sensitive to solution, vapor, and solid phase nitroaromatics, as well as solution borne RDX and PETN. Electronic supplementary information (ESI) available: Experimental details, Si-NC characterization, fluorescence spectra, solid residue testing and vapor study images. See DOI: 10.1039/c3nr06271f

  12. A coated-wire ion-selective electrode for ionic calcium measurements

    NASA Technical Reports Server (NTRS)

    Hines, John W.; Arnaud, Sara; Madou, Marc; Joseph, Jose; Jina, Arvind

    1991-01-01

    A coated-wire ion-selective electrode for measuring ionic calcium was developed, in collaboration with Teknektron Sensor Development Corporation (TSDC). This coated wire electrode sensor makes use of advanced, ion-responsive polyvinyl chloride (PVC) membrane technology, whereby the electroactive agent is incorporated into a polymeric film. The technology greatly simplifies conventional ion-selective electrode measurement technology, and is envisioned to be used for real-time measurement of physiological and environment ionic constituents, initially calcium. A primary target biomedical application is the real-time measurement of urinary and blood calcium changes during extended exposure to microgravity, during prolonged hospital or fracture immobilization, and for osteoporosis research. Potential advanced life support applications include monitoring of calcium and other ions, heavy metals, and related parameters in closed-loop water processing and management systems. This technology provides a much simplified ionic calcium measurement capability, suitable for both automated in-vitro, in-vivo, and in-situ measurement applications, which should be of great interest to the medical, scientific, chemical, and space life sciences communities.

  13. Pressure sensor

    SciTech Connect

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  14. Corrosion sensor

    DOEpatents

    Glass, R.S.; Clarke, W.L. Jr.; Ciarlo, D.R.

    1994-04-26

    A corrosion sensor array is described incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis. 7 figures.

  15. Corrosion sensor

    DOEpatents

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  16. Sensor assembly

    DOEpatents

    Bennett, Thomas E.; Nelson, Drew V.

    2004-04-13

    A ribbon-like sensor assembly is described wherein a length of an optical fiber embedded within a similar lengths of a prepreg tow. The fiber is ""sandwiched"" by two layers of the prepreg tow which are merged to form a single consolidated ribbon. The consolidated ribbon achieving a generally uniform distribution of composite filaments near the embedded fiber such that excess resin does not ""pool"" around the periphery of the embedded fiber.

  17. Gas Sensor

    NASA Technical Reports Server (NTRS)

    1990-01-01

    High Technology Sensors, Inc.'s Model SS-250 carbon dioxide detector uses a patented semiconductor optical source that efficiently creates infrared radiation, which is focused through an airway on a detector. Carbon dioxide passing through the airway absorbs the radiation causing the detector to generate a signal. The small size and low power requirements of the SS-250 make it attractive for incorporation in a variety of medical instruments.

  18. Chemical sensors

    DOEpatents

    Lowell, Jr., James R.; Edlund, David J.; Friesen, Dwayne T.; Rayfield, George W.

    1992-01-01

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material.

  19. Chemical sensors

    DOEpatents

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1992-06-09

    Sensors responsive to small changes in the concentration of chemical species are disclosed, comprising a mechanicochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment, either operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical or optical response, or adhered to a second inert polymeric strip, or doped with a conductive material. 12 figs.

  20. Position sensor

    NASA Technical Reports Server (NTRS)

    Auer, Siegfried (Inventor)

    1988-01-01

    A radiant energy angle sensor is provided wherein the sensitive portion thereof comprises a pair of linear array detectors with each detector mounted normal to the other to provide X and Y channels and a pair of slits spaced from the pair of linear arrays with each of the slits positioned normal to its associated linear array. There is also provided electrical circuit means connected to the pair of linear array detectors and to separate X and Y axes outputs.

  1. Calcium revisited: part II calcium supplements and their effects

    PubMed Central

    Lamy, Olivier; Burckhardt, Peter

    2014-01-01

    Calcium supplements were tested in pregnancy and lactation, in childhood and adolescence, in pre- and postmenopausal women and in elderly persons with various effects on bone density and fracture incidence. They must be properly chosen and adequately used. In this case, the reported minor negative side-effects do not restrict their use. All these aspects are reviewed here. PMID:25328675

  2. Estimation of presynaptic calcium currents and endogenous calcium buffers at the frog neuromuscular junction with two different calcium fluorescent dyes

    PubMed Central

    Samigullin, Dmitry; Fatikhov, Nijaz; Khaziev, Eduard; Skorinkin, Andrey; Nikolsky, Eugeny; Bukharaeva, Ellya

    2015-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dye Magnesium Green or the high-affinity dye Oregon Green BAPTA-1, simultaneously with microelectrode recordings of nerve-action potentials and end-plate currents. The action-potential-induced fluorescence signals in the nerve terminals developed much more slowly than the postsynaptic response. To clarify the reasons for this observation and to define a spatiotemporal profile of intracellular calcium and of the concentration of mobile and fixed calcium buffers, mathematical modeling was employed. The best approximations of the experimental calcium transients for both calcium dyes were obtained when the calcium current had an amplitude of 1.6 ± 0.08 pA and a half-decay time of 1.2 ± 0.06 ms, and when the concentrations of mobile and fixed calcium buffers were 250 ± 13 μM and 8 ± 0.4 mM, respectively. High concentrations of endogenous buffers define the time course of calcium transients after an action potential in the axoplasm, and may modify synaptic plasticity. PMID:25709579

  3. Calcium release from experimental dental materials.

    PubMed

    Okulus, Zuzanna; Buchwald, Tomasz; Voelkel, Adam

    2016-11-01

    The calcium release from calcium phosphate-containing experimental dental restorative materials was examined. The possible correlation of ion release with initial calcium content, solubility and degree of curing (degree of conversion) of examined materials was also investigated. Calcium release was measured with the use of an ion-selective electrode in an aqueous solution. Solubility was established by the weighing method. Raman spectroscopy was applied for the determination of the degree of conversion, while initial calcium content was examined with the use of energy-dispersive spectroscopy. For examined materials, the amount of calcium released was found to be positively correlated with solubility and initial calcium content. It was also found that the degree of conversion does not affect the ability of these experimental composites to release calcium ions. PMID:27524015

  4. DISSOLUTION AND CRYSTALLIZATION OF CALCIUM SULFITE PLATELETS

    EPA Science Inventory

    The paper discusses the dissolution and crystallization of calcium sulfite platelets. The rates of calcium sulfite dissolution and crystallization are important in slurry scrubbing processes for flue gas desulfurization. The rates affect the scrubber solution composition, SO2 abs...

  5. Magnesium/Calcium Competition at Excitable Membranes.

    ERIC Educational Resources Information Center

    Belzer, Bill; Fry, Panni

    1998-01-01

    Considers some consequences of altering intracellular calcium supply by magnesium concentration changes. Focuses on using this procedure as an exercise with allied health students as they witness therapeutic uses of magnesium and other calcium entry inhibitors. (DDR)

  6. Calcium, vitamin D, and your bones

    MedlinePlus

    ... can break easily, even without an obvious injury. Vitamin D helps your body absorb calcium. Eat foods that provide the right amounts of calcium, vitamin D, and protein. This kind of diet will give ...

  7. 7 CFR 58.434 - Calcium chloride.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Quality Specifications for Raw Material § 58.434 Calcium chloride. Calcium chloride, when used, shall meet the requirements of the...

  8. Dairy Dilemma: Are You Getting Enough Calcium?

    MedlinePlus

    ... Dairy Dilemma Dairy Dilemma Are You Getting Enough Calcium? You may be avoiding dairy products because of ... But dairy products are a major source of calcium, vitamin D and other nutrients that are important ...

  9. 21 CFR 184.1191 - Calcium carbonate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... three common methods of manufacture: (1) As a byproduct in the “Lime soda process”; (2) By precipitation of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation...

  10. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets...

  11. Calcium - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Calcium URL of this page: https://www.nlm.nih.gov/medlineplus/languages/calcium.html Other topics A-Z A B ...

  12. 21 CFR 184.1210 - Calcium oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium oxide. 184.1210 Section 184.1210 Food and... Substances Affirmed as GRAS § 184.1210 Calcium oxide. (a) Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. It is produced from calcium carbonate, limestone,...

  13. 21 CFR 184.1221 - Calcium propionate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium propionate. 184.1221 Section 184.1221 Food... Specific Substances Affirmed as GRAS § 184.1221 Calcium propionate. (a) Calcium propionate (C6H10CaO4, CAS Reg. No. 4075-81-4) is the calcium salt of propionic acid. It occurs as white crystals or...

  14. 21 CFR 184.1185 - Calcium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium acetate. 184.1185 Section 184.1185 Food and... Substances Affirmed as GRAS § 184.1185 Calcium acetate. (a) Calcium acetate (Ca (C2H3O2)2, CAS Reg. No. 62-54-4), also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may...

  15. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium stearate. 184.1229 Section 184.1229 Food... Specific Substances Affirmed as GRAS § 184.1229 Calcium stearate. (a) Calcium stearate (Ca(C17H35COO)2, CAS Reg. No. 1529-23-0) is the calcium salt of stearic acid derived from edible sources. It is prepared...

  16. Oxalic acid decreases calcium absorption in rats

    SciTech Connect

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

    1987-11-01

    Calcium absorption from salts and foods intrinsically labeled with /sup 45/Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO/sub 3/ and CaCl/sub 2/ than from CaC/sub 2/O/sub 4/ (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach.

  17. 21 CFR 184.1210 - Calcium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Substances Affirmed as GRAS § 184.1210 Calcium oxide. (a) Calcium oxide (CaO, CAS Reg. No. 1305-78-8) is also known as lime, quick lime, burnt lime, or calx. It is produced from calcium carbonate, limestone, or... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium oxide. 184.1210 Section 184.1210 Food...

  18. Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

    ERIC Educational Resources Information Center

    Liang, Willmann

    2008-01-01

    This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

  19. Calcium orthophosphates and human beings

    PubMed Central

    Dorozhkin, Sergey V.

    2012-01-01

    The historical development of a scientific knowledge on calcium orthophosphates from the 1770s until 1940 is described. Many forgotten and poorly known historical facts and approaches have been extracted from old publications and then they have been analyzed, systematized and reconsidered from the modern point of view. The chosen time scale starts with the earliest available studies of 1770s (to the best of my findings, calcium orthophosphates had been unknown before), passes through the entire 19th century and finishes in 1940, because since then the amount of publications on calcium orthophosphates rapidly increases and the subject becomes too broad. Furthermore, since publications of the second half of the 20th century are easily accessible, a substantial amount of them have already been reviewed by other researchers. The reported historical findings clearly demonstrate that the substantial amount of the scientific facts and experimental approaches have been known for very many decades and, in fact, the considerable quantity of relatively recent investigations on calcium orthophosphates is just either a further development of the earlier studies or a rediscovery of the already forgotten knowledge. PMID:23507803

  20. Calcium channels in Paramecium aurelia.

    PubMed

    Schein, S J

    1977-01-01

    Reversal of swimming direction in paramecium is dependent on the calcium influx through the excitable-membrane calcium channels. Several mutants of Paramecium aurelia have been selected on the basis of their resistance to the paralyzing effect of barium. The mutants have reduced reversal behavior and are in the same three pawn genes as discovered by Kung (16, 17). Also, in barium solutions, the pawns live longer than the wild-type; however, pwB mutants are more resistant to barium toxicity than pwA mutants. These results suggest that the selection picked up mutants in the calcium channel. Electrophysiological studies demonstrate this point directly, showing defective calcium activation in all pawns, but also defective anomalous rectification in pwB mutants. A model is presented which accounts for the differences between pwA and pwB mutants. It ascribes the depolarization-sensitive "gate" function to the pwA gene product and the "pore" function to the pwB gene product. Additionally, the stability of the channel structure is demonstrated, channel half-life being from five to eight days. PMID:928443

  1. Acute calcium pyrophosphate deposition arthropathy.

    PubMed

    Rosen, Thomas; Furman, Janet

    2016-06-01

    Acute calcium pyrophosphate deposition (CPPD) arthropathy, also called pseudogout, is common, and becomes more prevalent as patients age. The presenting symptoms are similar to both gout and septic arthritis but may be treated differently. This article describes a typical patient presentation and management from an emergency medicine and orthopedic surgery standpoint. PMID:27228038

  2. Calcium Kinetics During Space Flight

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; OBrien, K. O.; Abrams, S. A.; Wastney, M. E.

    2005-01-01

    Bone loss during space flight is one of the most critical challenges to astronaut health on space exploration missions. Defining the time course and mechanism of these changes will aid in developing means to counteract bone loss during space flight, and will have relevance for other clinical situations that impair weight-bearing activity. Bone health is a product of the balance between bone formation and bone resorption. Early space research could not clearly identify which of these was the main process altered in bone loss, but identification of the collagen crosslinks in the 1990s made possible a clear understanding that the impact of space flight was greater on bone resorption, with bone formation being unchanged or only slightly decreased. Calcium kinetics data showed that bone resorption was greater during flight than before flight (668 plus or minus 130 vs. 427 plus or minus 153 mg/d, p less than 0.001), and clearly documented that true intestinal calcium absorption was lower during flight than before flight (233 plus or minus 87 vs. 460 plus or minus 47 mg/d, p less than 0.01). Weightlessness had a detrimental effect on the balance in bone turnover: the difference between daily calcium balance during flight (-234 plus or minus 102 mg/d) and calcium balance before flight (63 plus or minus 75 mg/d) approached 300 mg/d (p less than 0.01). These data demonstrate that the bone loss that occurs during space flight is a consequence of increased bone resorption and decreased intestinal calcium absorption. Examining the changes in bone and calcium homeostasis in the initial days and weeks of space flight, as well as at later times on missions longer than 6 months, is critical to understanding the nature of bone adaptation to weightlessness. To increase knowledge of these changes, we studied bone adaptation to space flight on the 16-day Space Shuttle Columbia (STS-107) mission. When the brave and talented crew of Columbia were lost during reentry on the tragic morning

  3. Plant calcium content: Ready to remodel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    By identifying the relationship between calcium location in the plant cell and nutrient bioavailability, the plant characteristics leading to maximal calcium absorption by humans can be identified. Knowledge of plant cellular and molecular targets controlling calcium location in plants is emerging. ...

  4. 21 CFR 73.1070 - Calcium carbonate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine,...

  5. 21 CFR 573.240 - Calcium periodate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium periodate. 573.240 Section 573.240...

  6. 21 CFR 573.240 - Calcium periodate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240...

  7. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate may be safely used in food in accordance with the following prescribed conditions: (a) The food additive is the calcium salt of...

  8. 21 CFR 172.720 - Calcium lactobionate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Other Specific Usage Additives § 172.720 Calcium lactobionate. The food additive calcium lactobionate... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium lactobionate. 172.720 Section 172.720...

  9. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  10. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  11. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  12. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  13. 21 CFR 573.240 - Calcium periodate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES PERMITTED IN FEED AND DRINKING WATER OF ANIMALS Food Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used in... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium periodate. 573.240 Section 573.240...

  14. 21 CFR 182.8217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium phosphate. 182.8217 Section 182.8217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8217 Calcium phosphate. (a) Product. Calcium phosphate...

  15. 21 CFR 73.1070 - Calcium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine, white, synthetically prepared powder consisting essentially...

  16. 21 CFR 582.1195 - Calcium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.1195 Section 582.1195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1195 Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance...

  17. 21 CFR 582.1193 - Calcium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.1193 Section 582.1193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1193 Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This...

  18. 21 CFR 582.6197 - Calcium diacetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium diacetate. 582.6197 Section 582.6197 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium diacetate. (a) Product. Calcium diacetate. (b) Conditions of use. This substance is...

  19. 21 CFR 582.6195 - Calcium citrate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium citrate. 582.6195 Section 582.6195 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium citrate. (a) Product. Calcium citrate. (b) Conditions of use. This substance is...

  20. 21 CFR 582.1199 - Calcium gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium gluconate. 582.1199 Section 582.1199 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1199 Calcium gluconate. (a) Product. Calcium gluconate. (b) Conditions of use....

  1. 21 CFR 582.6185 - Calcium acetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium acetate. 582.6185 Section 582.6185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium acetate. (a) Product. Calcium acetate. (b) Conditions of use. This substance is...

  2. 21 CFR 582.1191 - Calcium carbonate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  3. 21 CFR 582.7187 - Calcium alginate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium alginate. 582.7187 Section 582.7187 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium alginate. (a) Product. Calcium alginate. (b) Conditions of use. This substance is...

  4. 21 CFR 184.1206 - Calcium iodate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium iodate. 184.1206 Section 184.1206 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1206 Calcium iodate. (a) Calcium iodate , also referred to as...

  5. 21 CFR 182.3225 - Calcium sorbate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sorbate. 182.3225 Section 182.3225 Food and... CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Chemical Preservatives § 182.3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is generally recognized...

  6. 21 CFR 182.2227 - Calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  7. 21 CFR 582.6219 - Calcium phytate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phytate. 582.6219 Section 582.6219 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium phytate. (a) Product. Calcium phytate. (b) Conditions of use. This substance is...

  8. 21 CFR 182.6203 - Calcium hexametaphosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium hexametaphosphate. 182.6203 Section 182.6203 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6203 Calcium hexametaphosphate. (a) Product. Calcium hexametaphosphate. (b) Conditions of use....

  9. 21 CFR 582.1205 - Calcium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  10. 21 CFR 582.6203 - Calcium hexametaphosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hexametaphosphate. 582.6203 Section 582.6203 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED....6203 Calcium hexametaphosphate. (a) Product. Calcium hexametaphosphate. (b) Conditions of use....

  11. 21 CFR 201.70 - Calcium labeling.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Calcium labeling. 201.70 Section 201.70 Food and... LABELING Labeling Requirements for Over-the-Counter Drugs § 201.70 Calcium labeling. (a) The labeling of over-the-counter (OTC) drug products intended for oral ingestion shall contain the calcium content...

  12. 21 CFR 582.1210 - Calcium oxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium oxide. 582.1210 Section 582.1210 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1210 Calcium oxide. (a) Product. Calcium oxide. (b) Conditions of use. This substance is...

  13. 21 CFR 582.6199 - Calcium gluconate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium gluconate. 582.6199 Section 582.6199 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium gluconate. (a) Product. Calcium gluconate. (b) Conditions of use. This substance is...

  14. 21 CFR 582.1207 - Calcium lactate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium lactate. 582.1207 Section 582.1207 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1207 Calcium lactate. (a) Product. Calcium lactate. (b) Conditions of use. This substance...

  15. 21 CFR 184.1230 - Calcium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium sulfate. 184.1230 Section 184.1230 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1230 Calcium sulfate. (a) Calcium sulfate (CaSO4, CAS Reg. No. 7778-18-9...

  16. 21 CFR 182.6197 - Calcium diacetate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium diacetate. 182.6197 Section 182.6197 Food... HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Sequestrants 1 § 182.6197 Calcium diacetate. (a) Product. Calcium diacetate. (b) Conditions of use. This substance is generally recognized...

  17. 21 CFR 582.3189 - Calcium ascorbate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium ascorbate. 582.3189 Section 582.3189 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3189 Calcium ascorbate. (a) Product. Calcium ascorbate. (b) Conditions of use. This substance...

  18. 21 CFR 582.3221 - Calcium propionate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium propionate. 582.3221 Section 582.3221 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3221 Calcium propionate. (a) Product. Calcium propionate. (b) Conditions of use. This substance...

  19. 21 CFR 582.6193 - Calcium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium chloride. 582.6193 Section 582.6193 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium chloride. (a) Product. Calcium chloride. (b) Conditions of use. This substance is...

  20. 21 CFR 582.2227 - Calcium silicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  1. 21 CFR 582.3225 - Calcium sorbate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium sorbate. 582.3225 Section 582.3225 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL....3225 Calcium sorbate. (a) Product. Calcium sorbate. (b) Conditions of use. This substance is...

  2. 21 CFR 182.3189 - Calcium ascorbate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium ascorbate. 182.3189 Section 182.3189 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Calcium ascorbate. (a) Product. Calcium ascorbate. (b) Conditions of use. This substance is...

  3. 7 CFR 58.434 - Calcium chloride.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Calcium chloride. 58.434 Section 58.434 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Material § 58.434 Calcium chloride. Calcium chloride, when used, shall meet the requirements of the...

  4. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  5. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  6. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  7. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  8. 21 CFR 582.5212 - Calcium pantothenate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium pantothenate. 582.5212 Section 582.5212 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5212 Calcium pantothenate. (a) Product. Calcium pantothenate. (b) Conditions of use....

  9. 21 CFR 73.1070 - Calcium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine, white, synthetically prepared powder consisting essentially...

  10. 21 CFR 582.1191 - Calcium carbonate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  11. 21 CFR 582.2227 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  12. 21 CFR 182.2227 - Calcium silicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  13. Abnormalities of serum calcium and magnesium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Neonatal hypocalcemia is defined as a total serum calcium concentration of <7 mg/dL or an ionized calcium concentration of <4 mg/dL (1mmol/L). In very low birth weight (VLBW) infants, ionized calcium values of 0.8 to 1 mmol/L are common and not usually associated with clinical symptoms. In larger in...

  14. Characterization of calcium carbonate/chitosan composites

    SciTech Connect

    Gonsalves, K.E.; Zhang, S.

    1995-12-31

    The crystal growth of calcium carbonate on a chitosan substrate was achieved using a supersaturated calcium carbonate solution, by using various additives, polyacrylic acid (PAA). Polyacrylic acid modified the chitosan-film surface and promoted the nucleation of calcium carbonate crystals.

  15. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  16. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  18. 21 CFR 582.1217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Calcium phosphate. 582.1217 Section 582.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  19. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food... GENERALLY RECOGNIZED AS SAFE Multiple Purpose GRAS Food Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic). (b) Conditions of use. This substance is...

  20. 21 CFR 182.1217 - Calcium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Calcium phosphate. 182.1217 Section 182.1217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  1. Facile and scalable disposable sensor based on laser engraved graphene for electrochemical detection of glucose

    NASA Astrophysics Data System (ADS)

    Tehrani, Farshad; Bavarian, Behzad

    2016-06-01

    A novel and highly sensitive disposable glucose sensor strip was developed using direct laser engraved graphene (DLEG) decorated with pulse deposited copper nanocubes (CuNCs). The high reproducibility (96.8%), stability (97.4%) and low cost demonstrated by this 3-step fabrication method indicates that it could be used for high volume manufacturing of disposable glucose strips. The fabrication method also allows for a high degree of flexibility, allowing for control of the electrode size, design, and functionalization method. Additionally, the excellent selectivity and sensitivity (4,532.2 μA/mM.cm2), low detection limit (250 nM), and suitable linear range of 25 μM–4 mM, suggests that these sensors may be a great potential platform for glucose detection within the physiological range for tear, saliva, and/or sweat.

  2. Facile and scalable disposable sensor based on laser engraved graphene for electrochemical detection of glucose

    PubMed Central

    Tehrani, Farshad; Bavarian, Behzad

    2016-01-01

    A novel and highly sensitive disposable glucose sensor strip was developed using direct laser engraved graphene (DLEG) decorated with pulse deposited copper nanocubes (CuNCs). The high reproducibility (96.8%), stability (97.4%) and low cost demonstrated by this 3-step fabrication method indicates that it could be used for high volume manufacturing of disposable glucose strips. The fabrication method also allows for a high degree of flexibility, allowing for control of the electrode size, design, and functionalization method. Additionally, the excellent selectivity and sensitivity (4,532.2 μA/mM.cm2), low detection limit (250 nM), and suitable linear range of 25 μM–4 mM, suggests that these sensors may be a great potential platform for glucose detection within the physiological range for tear, saliva, and/or sweat. PMID:27306706

  3. Calcium supplements: benefits and risks.

    PubMed

    Reid, I R; Bristow, S M; Bolland, M J

    2015-10-01

    Calcium is an essential element in the diet, but there is continuing controversy regarding its optimal intake, and its role in the pathogenesis of osteoporosis. Most studies show little evidence of a relationship between calcium intake and bone density, or the rate of bone loss. Re-analysis of data from the placebo group from the Auckland Calcium Study demonstrates no relationship between dietary calcium intake and rate of bone loss over 5 years in healthy older women with intakes varying from <400 to >1500 mg day(-1) . Thus, supplements are not needed within this range of intakes to compensate for a demonstrable dietary deficiency, but might be acting as weak anti-resorptive agents via effects on parathyroid hormone and calcitonin. Consistent with this, supplements do acutely reduce bone resorption and produce small short-term effects on bone density, without evidence of a cumulative density benefit. As a result, anti-fracture efficacy remains unproven, with no evidence to support hip fracture prevention (other than in a cohort with severe vitamin D deficiency) and total fracture numbers are reduced by 0-10%, depending on which meta-analysis is considered. Five recent large studies have failed to demonstrate fracture prevention in their primary analyses. This must be balanced against an increase in gastrointestinal side effects (including a doubling of hospital admissions for these problems), a 17% increase in renal calculi and a 20-40% increase in risk of myocardial infarction. Each of these adverse events alone neutralizes any possible benefit in fracture prevention. Thus, calcium supplements appear to have a negative risk-benefit effect, and so should not be used routinely in the prevention or treatment of osteoporosis. PMID:26174589

  4. Visualizing Presynaptic Calcium Dynamics and Vesicle Fusion with a Single Genetically Encoded Reporter at Individual Synapses.

    PubMed

    Jackson, Rachel E; Burrone, Juan

    2016-01-01

    Synaptic transmission depends on the influx of calcium into the presynaptic compartment, which drives neurotransmitter release. Genetically encoded reporters are widely used tools to understand these processes, particularly pHluorin-based reporters that report vesicle exocytosis and endocytosis through pH dependent changes in fluorescence, and genetically encoded calcium indicators (GECIs) that exhibit changes in fluorescence upon binding to calcium. The recent expansion of the color palette of available indicators has made it possible to image multiple probes simultaneously within a cell. We have constructed a single molecule reporter capable of concurrent imaging of both presynaptic calcium influx and exocytosis, by fusion of sypHy, the vesicle associated protein synaptophysin containing a GFP-based pHluorin sensor, with the red-shifted GECI R-GECO1. Due to the fixed stoichiometry of the two probes, the ratio of the two responses can also be measured, providing an all optical correlate of the calcium dependence of release. Here, we have characterized stimulus-evoked sypHy-RGECO responses of hippocampal synapses in vitro, exploring the effects of different stimulus strengths and frequencies as well as variations in external calcium concentrations. By combining live sypHy-RGECO imaging with post hoc fixation and immunofluorescence, we have also investigated correlations between structural and functional properties of synapses. PMID:27507942

  5. Visualizing Presynaptic Calcium Dynamics and Vesicle Fusion with a Single Genetically Encoded Reporter at Individual Synapses

    PubMed Central

    Jackson, Rachel E.; Burrone, Juan

    2016-01-01

    Synaptic transmission depends on the influx of calcium into the presynaptic compartment, which drives neurotransmitter release. Genetically encoded reporters are widely used tools to understand these processes, particularly pHluorin-based reporters that report vesicle exocytosis and endocytosis through pH dependent changes in fluorescence, and genetically encoded calcium indicators (GECIs) that exhibit changes in fluorescence upon binding to calcium. The recent expansion of the color palette of available indicators has made it possible to image multiple probes simultaneously within a cell. We have constructed a single molecule reporter capable of concurrent imaging of both presynaptic calcium influx and exocytosis, by fusion of sypHy, the vesicle associated protein synaptophysin containing a GFP-based pHluorin sensor, with the red-shifted GECI R-GECO1. Due to the fixed stoichiometry of the two probes, the ratio of the two responses can also be measured, providing an all optical correlate of the calcium dependence of release. Here, we have characterized stimulus-evoked sypHy-RGECO responses of hippocampal synapses in vitro, exploring the effects of different stimulus strengths and frequencies as well as variations in external calcium concentrations. By combining live sypHy-RGECO imaging with post hoc fixation and immunofluorescence, we have also investigated correlations between structural and functional properties of synapses. PMID:27507942

  6. Label-free colorimetric sensor for mercury(II) and DNA on the basis of mercury(II) switched-on the oxidase-mimicking activity of silver nanoclusters.

    PubMed

    Wang, Guang-Li; Jin, Lu-Yi; Wu, Xiu-Ming; Dong, Yu-Ming; Li, Zai-Jun

    2015-04-29

    In this paper, a novel colorimetric biosensor for Hg(2+) and DNA molecules is presented based on Hg(2+) stimulated oxidase-like activity of bovine serum albumin protected silver clusters (BSA-Ag NCs). Under mild conditions, Hg(2+) activated BSA-Ag NCs to show high catalytic activity toward the oxidation of 3,3',5, 5'-tetramethylbenzidine (TMB) using ambient dissolved oxygen as an oxidant. The oxidase-like activity of BSA-Ag NCs was "switched-on" selectively in the presence of Hg(2+), which permitted a novel and facile colorimetric sensor for Hg(2+). As low as 25 nmol L(-1)Hg(2+) could be detected with a linear range from 80 nmol L(-1) to 50 mmol L(-1). In addition, the sensing strategy was also employed to detect DNA molecules. Hg(2+) is known to bind very strongly and specifically with two DNA thymine bases (T) to form thymine-Hg(2+)-thymine (T-Hg(2+)-T) base pairs. The hairpin-structure was disrupted and Hg(2+) ions were released after hybridization with the DNA target. By coupling the Hg(2+) switched-on the oxidase-mimicking activity of BSA-Ag NCs, we developed a novel label-free strategy for facile and fast colorimetric detection of DNA molecules. More important, target DNA can be detected as low as 10 nmol L(-1) with a linear range from 30 to 225 nmol L(-1). Compared with other methods, this method presents several advantages such as the independence of hydrogen peroxide, high sensitivity and good selectivity, avoiding any modification or immobilization of DNA, which holds a great potential of metal NCs for clinical application in biosensing and biotechnology. PMID:25847155

  7. Ultrafast light-induced spin-state trapping photophysics investigated in Fe(phen)2(NCS)2 spin-crossover crystal.

    PubMed

    Bertoni, Roman; Cammarata, Marco; Lorenc, Maciej; Matar, Samir F; Létard, Jean-François; Lemke, Henrik T; Collet, Eric

    2015-03-17

    Few photoactive molecules undergo a complete transformation of physical properties (magnetism, optical absorption, etc.) when irradiated with light. Such phenomena can happen on the time scale of fundamental atomic motions leading to an entirely new state within less than 1 ps following light absorption. Spin crossover (SCO) molecules are prototype systems having the ability to switch between low spin (LS) and high spin (HS) molecular states both at thermal equilibrium and after light irradiation. In the case of Fe(II) (3d(6)) complexes in a nearly octahedral ligand field, the two possible electronic distributions among the 3d split orbitals are S = 0 for the LS diamagnetic state and S = 2 for the HS paramagnetic state. In crystals, such photoexcited states can be long-lived at low temperature, as is the case for the photoinduced HS state of the [Fe(phen)2(NCS)2] SCO compound investigated here. We first show how such bistability between the diamagnetic and paramagnetic states can be characterized at thermal equilibrium or after light irradiation at low temperature. Complementary techniques provide invaluable insights into relationships between changes of electronic states and structural reorganization. But the development of such light-active materials requires the understanding of the basic mechanism following light excitation of molecules, responsible for trapping them into new electronic and structural states. We therefore discuss how we can observe a photomagnetic molecule during switching and catch on the fly electronic and structural molecular changes with ultrafast X-ray and optical absorption spectroscopies. In addition, there is a long debate regarding the mechanism behind the efficiency of such a light-induced process. Recent theoretical works suggest that such speed and efficiency are possible thanks to the instantaneous coupling with the phonons of the final state. We discuss here the first experimental proof of that statement as we observe the

  8. Influenza sensor

    DOEpatents

    Swanson, Basil I.; Song, Xuedong; Unkefer, Clifford; Silks, III, Louis A.; Schmidt, Jurgen G.

    2003-09-30

    A sensor for the detection of tetrameric multivalent neuraminidase within a sample is disclosed, where a positive detection indicates the presence of a target virus within the sample. Also disclosed is a trifunctional composition of matter including a trifunctional linker moiety with groups bonded thereto including (a) an alkyl chain adapted for attachment to a substrate, (b) a fluorescent moiety capable of generating a fluorescent signal, and (c) a recognition moiety having a spacer group of a defined length thereon, the recognition moiety capable of binding with tetrameric multivalent neuraminidase.

  9. Influenza Sensor

    DOEpatents

    Swanson, Basil I.; Song, Xuedong; Unkefer, Clifford; Silks, III, Louis A.; Schmidt, Jurgen G.

    2006-03-28

    A sensor for the detection of tetrameric multivalent neuraminidase within a sample is disclosed, where a positive detection indicates the presence of a target virus within the sample. Also disclosed is a trifunctional composition of matter including a trifunctional linker moiety with groups bonded thereto including (a) an alkyl chain adapted for attachment to a substrate, (b) a fluorescent moiety capable of generating a fluorescent signal, and (c) a recognition moiety having a spacer group of a defined length thereon, the recognition moiety capable of binding with tetrameric multivalent neuraminidase.

  10. Influenza Sensor

    DOEpatents

    Swanson, Basil I.; Song, Xuedong; Unkefer, Clifford; Silks, III, Louis A.; Schmidt, Jurgen G.

    2005-05-17

    A sensor for the detection of tetrameric multivalent neuraminidase within a sample is disclosed, where a positive detection indicates the presence of a target virus within the sample. Also disclosed is a trifunctional composition of matter including a trifunctional linker moiety with groups bonded thereto including (a) an alkyl chain adapted for attachment to a substrate, (b) a fluorescent moiety capable of generating a fluorescent signal, and (c) a recognition moiety having a spacer group of a defined length thereon, the recognition moiety capable of binding with tetrameric multivalent neuraminidase.

  11. Hydrogen sensor

    DOEpatents

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  12. Apatite Formation from Amorphous Calcium Phosphate and Mixed Amorphous Calcium Phosphate/Amorphous Calcium Carbonate.

    PubMed

    Ibsen, Casper J S; Chernyshov, Dmitry; Birkedal, Henrik

    2016-08-22

    Crystallization from amorphous phases is an emerging pathway for making advanced materials. Biology has made use of amorphous precursor phases for eons and used them to produce structures with remarkable properties. Herein, we show how the design of the amorphous phase greatly influences the nanocrystals formed therefrom. We investigate the transformation of mixed amorphous calcium phosphate/amorphous calcium carbonate phases into bone-like nanocrystalline apatite using in situ synchrotron X-ray diffraction and IR spectroscopy. The speciation of phosphate was controlled by pH to favor HPO4 (2-) . In a carbonate free system, the reaction produces anisotropic apatite crystallites with large aspect ratios. The first formed crystallites are highly calcium deficient and hydrogen phosphate rich, consistent with thin octacalcium phosphate (OCP)-like needles. During growth, the crystallites become increasingly stoichiometric, which indicates that the crystallites grow through addition of near-stoichiometric apatite to the OCP-like initial crystals through a process that involves either crystallite fusion/aggregation or Ostwald ripening. The mixed amorphous phases were found to be more stable against phase transformations, hence, the crystallization was inhibited. The resulting crystallites were smaller and less anisotropic. This is rationalized by the idea that a local phosphate-depletion zone formed around the growing crystal until it was surrounded by amorphous calcium carbonate, which stopped the crystallization. PMID:27460160

  13. A quantum sensor for high-performance mass spectrometry

    NASA Astrophysics Data System (ADS)

    Rodríguez, D.

    2012-06-01

    A novel device, called quantum sensor, has been conceived to measure the mass of a single ion with ultimate accuracy and unprecedented sensitivity while the ion is stored and cooled in a trap. The quantum sensor consists of a single calcium ion as sensor, which is laser cooled to mK temperatures and stored in a second trap connected to the trap for the ion under study by a common endcap. The cyclotron motion of the ion under investigation is transformed into axial motion along the magnetic field lines and coupled to the sensor ion by the image current induced in the common endcap. The axial motion of the sensor ion in turn is monitored spatially resolved by its fluorescence light. In this way the detection of phonons can be upgraded to a detection of photons. This device will allow one to overcome recent limitations in high-precision mass spectrometry.

  14. The preparation of calcium superoxide from calcium peroxide diperoxyhydrate

    NASA Technical Reports Server (NTRS)

    Ballou, E. V.; Wood, P. C.; Spitze, L. A.; Wydeven, T.

    1977-01-01

    There is interest in solid materials containing a high percentage of stored oxygen for use in emergency breathing apparatus for miners and as auxiliary oxygen sources for astronauts. In theory, the amount of available oxygen in calcium superoxide, Ca(O2)2 is higher than in potassium superoxide, KO2, and its availability during use should be unhindered by the formation of a low melting and hydrous coating. The decomposition of solid calcium peroxide diperoxyhydrate, CaO2.2H2O2 has been studied, using an apparatus which allows good control of the critical reaction parameters. Samples have been prepared showing apparent superoxide contents in excess of those previously reported and higher than the theoretical 58.4% expected from a disproportionation reaction.

  15. Calcium signals and calcium channels in osteoblastic cells

    NASA Technical Reports Server (NTRS)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  16. Computational study of a calcium release-activated calcium channel

    NASA Astrophysics Data System (ADS)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

    The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

  17. Regulation of Calcium signaling through spatial Organization

    NASA Astrophysics Data System (ADS)

    Ullah, Aman; Ullah, Ghanim; Machaca, Khalid; Jung, Peter

    2010-03-01

    Calcium waves and signals in oocytes are produced and sustained by the release of Ca^2+ from the Endoplasmic Reticulum (ER) through clustered release channels. Changes in the spatial organization of calcium signaling effectors regulate the spatiotemporal features of the calcium signal as is e.g. observed during oocyte maturation. We report here how specific changes in the clustering of the calcium release channels in conjunction with physiologic alterations of other signaling effectors can affect a) the sensitivity of the signaling machinery to external factors, b) the time course of global intracellular signals and c), the speed and propagation range of intracellular calcium waves.

  18. Microcantilever sensor

    DOEpatents

    Thundat, Thomas G.; Wachter, Eric A.

    1998-01-01

    An improved microcantilever sensor is fabricated with at least one microcantilever attached to a piezoelectric transducer. The microcantilever is partially surface treated with a compound selective substance having substantially exclusive affinity for a targeted compound in a monitored atmosphere. The microcantilever sensor is also provided with a frequency detection means and a bending detection means. The frequency detection means is capable of detecting changes in the resonance frequency of the vibrated microcantilever in the monitored atmosphere. The bending detection means is capable of detecting changes in the bending of the vibrated microcantilever in the monitored atmosphere coactively with the frequency detection means. The piezoelectric transducer is excited by an oscillator means which provides a signal driving the transducer at a resonance frequency inducing a predetermined order of resonance on the partially treated microcantilever. Upon insertion into a monitored atmosphere, molecules of the targeted chemical attach to the treated regions of the microcantilever resulting in a change in oscillating mass as well as a change in microcantilever spring constant thereby influencing the resonant frequency of the microcantilever oscillation. Furthermore, the molecular attachment of the target chemical to the treated regions induce areas of mechanical strain in the microcantilever consistent with the treated regions thereby influencing microcantilever bending. The rate at which the treated microcantilever accumulates the target chemical is a function of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change and bending is related to the concentration of target chemical within the monitored atmosphere.

  19. Semiconductor sensors

    NASA Technical Reports Server (NTRS)

    Gatos, Harry C. (Inventor); Lagowski, Jacek (Inventor)

    1977-01-01

    A semiconductor sensor adapted to detect with a high degree of sensitivity small magnitudes of a mechanical force, presence of traces of a gas or light. The sensor includes a high energy gap (i.e., .about. 1.0 electron volts) semiconductor wafer. Mechanical force is measured by employing a non-centrosymmetric material for the semiconductor. Distortion of the semiconductor by the force creates a contact potential difference (cpd) at the semiconductor surface, and this cpd is determined to give a measure of the force. When such a semiconductor is subjected to illumination with an energy less than the energy gap of the semiconductors, such illumination also creates a cpd at the surface. Detection of this cpd is employed to sense the illumination itself or, in a variation of the system, to detect a gas. When either a gas or light is to be detected and a crystal of a non-centrosymmetric material is employed, the presence of gas or light, in appropriate circumstances, results in a strain within the crystal which distorts the same and the distortion provides a mechanism for qualitative and quantitative evaluation of the gas or the light, as the case may be.

  20. Force sensor

    DOEpatents

    Grahn, Allen R.

    1993-01-01

    A force sensor and related method for determining force components. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

  1. Force sensor

    DOEpatents

    Grahn, A.R.

    1993-05-11

    A force sensor and related method for determining force components is described. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

  2. Microcantilever sensor

    DOEpatents

    Thundat, T.G.; Wachter, E.A.

    1998-02-17

    An improved microcantilever sensor is fabricated with at least one microcantilever attached to a piezoelectric transducer. The microcantilever is partially surface treated with a compound selective substance having substantially exclusive affinity for a targeted compound in a monitored atmosphere. The microcantilever sensor is also provided with a frequency detection means and a bending detection means. The frequency detection means is capable of detecting changes in the resonance frequency of the vibrated microcantilever in the monitored atmosphere. The bending detection means is capable of detecting changes in the bending of the vibrated microcantilever in the monitored atmosphere coactively with the frequency detection means. The piezoelectric transducer is excited by an oscillator means which provides a signal driving the transducer at a resonance frequency inducing a predetermined order of resonance on the partially treated microcantilever. Upon insertion into a monitored atmosphere, molecules of the targeted chemical attach to the treated regions of the microcantilever resulting in a change in oscillating mass as well as a change in microcantilever spring constant thereby influencing the resonant frequency of the microcantilever oscillation. Furthermore, the molecular attachment of the target chemical to the treated regions induce areas of mechanical strain in the microcantilever consistent with the treated regions thereby influencing microcantilever bending. The rate at which the treated microcantilever accumulates the target chemical is a function of the target chemical concentration. Consequently, the extent of microcantilever oscillation frequency change and bending is related to the concentration of target chemical within the monitored atmosphere. 16 figs.

  3. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    PubMed Central

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intestinal absorption process was significantly different among the four calcium salts. The rank of absolute bioavailability of calcium was calcium ascorbate > calcium L-lactate ≥ calcium acetate > calcium chloride. The mean residence time (MRTab) of calcium from calcium ascorbate (32.2 minutes) in the intestinal tract was much longer than that from calcium L-lactate (9.5 minutes), calcium acetate (15.0 minutes) and calcium chloride (13.6 minutes). Furthermore, the foods di-D-fructo-furanose-1,2′:2,3′-dianhydride, sudachi (Citrus sudachi) juice, and moromi-su (a Japanese vinegar) increased the absolute bioavailability of calcium from calcium chloride by 2.46-fold, 2.86-fold, and 1.23-fold, respectively, and prolonged MRTab by 48.5 minutes, 43.1 minutes, and 44.9 minutes, respectively. In conclusion, the prolonged MRTab of calcium in the intestinal tract by anion or food might cause the increased absorbability of calcium.

  4. Substitution of calcium by strontium within selected calcium phosphates

    NASA Astrophysics Data System (ADS)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  5. Vegetable Bitterness is Related to Calcium Content

    PubMed Central

    Tordoff, Michael G.; Sandell, Mari A.

    2009-01-01

    In the U.S. and Europe, most people do not consume the recommended amounts of either calcium or vegetables. We investigated whether there might be a connection; specifically, whether the taste of calcium in vegetables contributes to their bitterness and thus acceptability. We found a strong correlation between the calcium content of 24 vegetables, based on USDA Nutrient Database values, and bitterness, based on the average ratings of 35 people (r = 0.93). Correlations between the content of other nutrients and bitterness were lower and most were not statistically significant. To assess whether it is feasible that humans can detect calcium in vegetables we tested two animal models known to display a calcium appetite. Previous work indicates that calcium solutions are preferentially ingested by PWK/PhJ mice relative to C57BL/6J mice, and by rats deprived of dietary calcium relative to replete controls. In choice tests between collard greens, a high-calcium vegetable, and cabbage, a low-calcium vegetable, the calcium-favoring animals had higher preferences for collard greens than did controls. These observations raise the possibility that the taste of calcium contributes to the bitterness and thus acceptability of vegetables. PMID:19260165

  6. Vegetable bitterness is related to calcium content.

    PubMed

    Tordoff, Michael G; Sandell, Mari A

    2009-04-01

    In the U.S. and Europe, most people do not consume the recommended amounts of either calcium or vegetables. We investigated whether there might be a connection; specifically, whether the taste of calcium in vegetables contributes to their bitterness and thus acceptability. We found a strong correlation between the calcium content of 24 vegetables, based on USDA Nutrient Database values, and bitterness, based on the average ratings of 35 people (r = 0.93). Correlations between the content of other nutrients and bitterness were lower and most were not statistically significant. To assess whether it is feasible that humans can detect calcium in vegetables we tested two animal models known to display a calcium appetite. Previous work indicates that calcium solutions are preferentially ingested by PWK/PhJ mice relative to C57BL/6J mice, and by rats deprived of dietary calcium relative to replete controls. In choice tests between collard greens, a high-calcium vegetable, and cabbage, a low-calcium vegetable, the calcium-favoring animals had higher preferences for collard greens than did controls. These observations raise the possibility that the taste of calcium contributes to the bitterness and thus acceptability of vegetables. PMID:19260165

  7. Seasonal Variations in Mercury's Dayside Calcium Exosphere

    NASA Technical Reports Server (NTRS)

    Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee W.; Vervack, Ronald J., Jr.; Cassidy, Timothy A.; Sarantos, Menelaos

    2014-01-01

    The Mercury Atmospheric and Surface Composition Spectrometer on the MESSENGER spacecraft has observed calcium emission in Mercury's exosphere on a near-daily basis since March 2011. During MESSENGER's primary and first extended missions (March 2011 - March 2013) the dayside calcium exosphere was measured over eight Mercury years. We have simulated these data with a Monte Carlo model of exospheric source processes to show that (a) there is a persistent source of energetic calcium located in the dawn equatorial region, (b) there is a seasonal dependence in the calcium source rate, and (c) there are no obvious year-to-year variations in the near-surface dayside calcium exosphere. Although the precise mechanism responsible for ejecting the calcium has not yet been determined, the most likely process is the dissociation of Ca-bearing molecules produced in micrometeoroid impact plumes to form energetic, escaping calcium atoms.

  8. Ways of calcium reabsorption in the kidney.

    PubMed

    Moor, Matthias B; Bonny, Olivier

    2016-06-01

    The role of the kidney in calcium homeostasis has been reshaped from a classic view in which the kidney was regulated by systemic calcitropic hormones such as vitamin D3 or parathyroid hormone to an organ actively taking part in the regulation of calcium handling. With the identification of the intrinsic renal calcium-sensing receptor feedback system, the regulation of paracellular calcium transport involving claudins, and new paracrine regulators such as klotho, the kidney has emerged as a crucial modulator not only of calciuria but also of calcium homeostasis. This review summarizes recent molecular and endocrine contributors to renal calcium handling and highlights the tight link between calcium and sodium reabsorption in the kidney. PMID:27009338

  9. [Effects of different form calcium on growth and tissue calcium level in rats].

    PubMed

    Xu, Q; Yin, S A; Hu, S; Zhao, X; Meng, J; Ge, K Y

    1997-01-01

    In order to solve the problem of calcium deficiency and to look for economic and efficient source of calcium, the effects of calcium carbonate, active calcium and calcium lactate on growth, development and tissue calcium level in rats were compared. Fifty-six 3-week old weaning rats were fed with calcium deficient diet (containing vitamin D 500 IU per kg diet) for 3 weeks, and then were divided into four groups randomly with 14 rats in each group, half male and half female. The diet of control group (A) was the basic diet, while the three experiment diets were supplemented with calcium carbonate (B), active calcium (C) and calcium lactate (D) (3000 mg calcium per kg diet), respectively. The experiment term was 12 weeks. The results showed that the body weight and length of calcium supplemented group were significantly higher than that of control group (P<0.05). Among the calcium supplemented groups, no significant differences were observed except the difference of body length between the group D and the group A in female. Calcium deficiency dramatically hindered the development with reduced dietary intake and decreased food consumption efficiency. The calcium levels in plasma, red blood cells and liver were significantly higher in the supplemented groups than that in the control group (P<0.05), however, there was no difference among the supplemented groups. No significant difference of calcium levels in muscle and heart was observed among all groups. Based on needs for reaching the RDA with additional 400 mg/d from present calcium status in Chinese population, the calcium carbonate is the most economic one and the ideal calcium source for supplementation. PMID:15747462

  10. Sensors, Update 1

    NASA Astrophysics Data System (ADS)

    Baltes, Henry; Göpel, Wolfgang; Hesse, Joachim

    1996-12-01

    Sensors Update ensures that you stay at the cutting edge of the field. Built upon the series Sensors, it presents an overview of highlights in the field. Treatments include current developments in materials, design, production, and applications of sensors, signal detection and processing, as well as new sensing principles. Furthermore, the sensor market as well as peripheral aspects such as standards are covered. Each volume is divided into four sections. Sensor Technology, reviews highlights in applied and basic research, Sensor Applications, covers new or improved applications of sensors, Sensor Markets, provides an overview of suppliers and market trends for a particular section, and Sensor Standards, reviews recent legislation and requirements for sensors. With this unique combination of information in each volume, Sensors Update will be of value for scientists and engineers in industry and at universities, to sensors developers, distributors, and users.

  11. Mass Sensor

    SciTech Connect

    Adams, B.E.

    2001-01-18

    The purpose of this CRADA was to use Honeywell's experience in low temperature cofire ceramics and traditional ceramics to assemble a relatively low-cost, mass-producible miniature mass analyzer. The specific design, given to us by Mass Sensors, LLC, was used to test for helium. The direct benefit for the participant was to have a prototype unit assembled for the purpose of proof of concept and the ability to secure venture capital investors. From that, the company would begin producing their own product for sale. The consumer/taxpayer benefits come from the wide variety of industries that can utilize this technology to improve quality of life. Medical industry can use this technology to improve diagnostic ability; manufacturing industry can use it for improved air, water, and soil monitoring to minimize pollution; and the law enforcement community can use this technology for identification of substances. These are just a few examples of the benefit of this technology. The benefits to DOE were in the area of process improvement for cofire and ceramic materials. From this project we demonstrated nonlinear thickfilm fine lines and spaces that were 5-mil wide with 5-mil spaces; determined height-to diameter-ratios for punched and filled via holes; demonstrated the ability to punch and fill 5-mil microvias; developed and demonstrated the capability to laser cut difficult geometries in 40-mil ceramic; developed and demonstrated coupling LTCC with standard alumina and achieving hermetic seals; developed and demonstrated three-dimensional electronic packaging concepts; and demonstrated printing variable resistors within 1% of the nominal value and within a tightly defined ratio. The capability of this device makes it invaluable for many industries. The device could be used to monitor air samples around manufacturing plants. It also could be used for monitoring automobile exhaust, for doing blood gas analysis, for sampling gases being emitted by volcanoes, for studying

  12. [Calcium pyrophosphate dihydrate deposition disease].

    PubMed

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  13. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    PubMed

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  14. Early redox, Src family kinase, and calcium signaling integrate wound responses and tissue regeneration in zebrafish

    PubMed Central

    Yoo, Sa Kan; Freisinger, Christina M.; LeBert, Danny C.

    2012-01-01

    Tissue injury can lead to scar formation or tissue regeneration. How regenerative animals sense initial tissue injury and transform wound signals into regenerative growth is an unresolved question. Previously, we found that the Src family kinase (SFK) Lyn functions as a redox sensor in leukocytes that detects H2O2 at wounds in zebrafish larvae. In this paper, using zebrafish larval tail fins as a model, we find that wounding rapidly activated SFK and calcium signaling in epithelia. The immediate SFK and calcium signaling in epithelia was important for late epimorphic regeneration of amputated fins. Wound-induced activation of SFKs in epithelia was dependent on injury-generated H2O2. A SFK member, Fynb, was responsible for fin regeneration. This work provides a new link between early wound responses and late regeneration and suggests that redox, SFK, and calcium signaling are immediate “wound signals” that integrate early wound responses and late epimorphic regeneration. PMID:23045550

  15. Simulation strategies for calcium microdomains and calcium-regulated calcium channels.

    PubMed

    von Wegner, Frederic; Wieder, Nicolas; Fink, Rainer H A

    2012-01-01

    In this article, we present an overview of simulation strategies in the context of subcellular domains where calcium-dependent signaling plays an important role. The presentation follows the spatial and temporal scales involved and represented by each algorithm. As an exemplary cell type, we will mainly cite work done on striated muscle cells, i.e. skeletal and cardiac muscle. For these cells, a wealth of ultrastructural, biophysical and electrophysiological data is at hand. Moreover, these cells also express ubiquitous signaling pathways as they are found in many other cell types and thus, the generalization of the methods and results presented here is straightforward.The models considered comprise the basic calcium signaling machinery as found in most excitable cell types including Ca(2+) ions, diffusible and stationary buffer systems, and calcium regulated calcium release channels. Simulation strategies can be differentiated in stochastic and deterministic algorithms. Historically, deterministic approaches based on the macroscopic reaction rate equations were the first models considered. As experimental methods elucidated highly localized Ca(2+) signaling events occurring in femtoliter volumes, stochastic methods were increasingly considered. However, detailed simulations of single molecule trajectories are rarely performed as the computational cost implied is too large. On the mesoscopic level, Gillespie's algorithm is extensively used in the systems biology community and with increasing frequency also in models of microdomain calcium signaling. To increase computational speed, fast approximations were derived from Gillespie's exact algorithm, most notably the chemical Langevin equation and the τ-leap algorithm. Finally, in order to integrate deterministic and stochastic effects in multiscale simulations, hybrid algorithms are increasingly used. These include stochastic models of ion channels combined with deterministic descriptions of the calcium buffering

  16. Kinetics of calcium sulfoaluminate formation from tricalcium aluminate, calcium sulfate and calcium oxide

    SciTech Connect

    Li, Xuerun Zhang, Yu; Shen, Xiaodong Wang, Qianqian; Pan, Zhigang

    2014-01-15

    The formation kinetics of tricalcium aluminate (C{sub 3}A) and calcium sulfate yielding calcium sulfoaluminate (C{sub 4}A{sub 3}$) and the decomposition kinetics of calcium sulfoaluminate were investigated by sintering a mixture of synthetic C{sub 3}A and gypsum. The quantitative analysis of the phase composition was performed by X-ray powder diffraction analysis using the Rietveld method. The results showed that the formation reaction 3Ca{sub 3}Al{sub 2}O{sub 6} + CaSO{sub 4} → Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 6CaO was the primary reaction < 1350 °C with and activation energy of 231 ± 42 kJ/mol; while the decomposition reaction 2Ca{sub 4}Al{sub 6}O{sub 12}(SO{sub 4}) + 10CaO → 6Ca{sub 3}Al{sub 2}O{sub 6} + 2SO{sub 2} ↑ + O{sub 2} ↑ primarily occurred beyond 1350 °C with an activation energy of 792 ± 64 kJ/mol. The optimal formation region for C{sub 4}A{sub 3}$ was from 1150 °C to 1350 °C and from 6 h to 1 h, which could provide useful information on the formation of C{sub 4}A{sub 3}$ containing clinkers. The Jander diffusion model was feasible for the formation and decomposition of calcium sulfoaluminate. Ca{sup 2+} and SO{sub 4}{sup 2−} were the diffusive species in both the formation and decomposition reactions. -- Highlights: •Formation and decomposition of calcium sulphoaluminate were studied. •Decomposition of calcium sulphoaluminate combined CaO and yielded C{sub 3}A. •Activation energy for formation was 231 ± 42 kJ/mol. •Activation energy for decomposition was 792 ± 64 kJ/mol. •Both the formation and decomposition were controlled by diffusion.

  17. Hysteretic behavior of Fe(phen){sub 2}(NCS){sub 2} spin-transition microparticles vs. the environment: A huge reversible component resolved by first order reversal curves

    SciTech Connect

    Tanasa, Radu; Stancu, Alexandru; Enachescu, Cristian; Laisney, Jérôme; Boillot, Marie-Laure

    2014-01-20

    We discuss the influence of the embedding matrix on the thermal hysteretic behavior of spin transition microparticles of Fe(phen){sub 2}(NCS){sub 2} by using a series of experimental first order reversal curves (FORCs). The shape of FORCs supports the hypothesis considering additional interactions between the spin-transition microparticles and the embedding matrix, which compares to a negative pressure on the particles. A mean-field approach based on negative variable external pressures, together with a cut off/switch on of particles-matrix interactions accounts for the experimental features.

  18. Kinetics of light-induced first-order phase transformation in molecular solids: Fe(btr){sub 2}(NCS){sub 2}{center_dot}H{sub 2}O

    SciTech Connect

    Pillet, S.; Legrand, V.; Souhassou, M.; Lecomte, C.

    2006-10-01

    The mechanism and kinetics of the thermally and light-induced spin transition of the highly cooperative spin crossover material Fe(btr){sub 2}(NCS){sub 2}{center_dot}H{sub 2}O (btr=4,4'-bis-1,2,4-triazole) have been investigated by single crystal x-ray diffraction techniques. The key role of like-spin domains is quantitatively analyzed through a nucleation, growing, and coarsening mechanism whose kinetics follow the Kolmogorov-Johnson-Mehl-Avrami model with low dimensional characteristics.

  19. Stress-induced ligand field distribution and consequent multi-mode spin crossover in Fe II(phen) 2(NCS) 2 and Fe II[HB(pz) 3] 2

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Naoko; Tsukamoto, Atsushi; Ohshita, Tadashi; Isobe, Tetsuhiko; Senna, Mamoru; Yoshioka, Naoki; Inoue, Hidenari

    2001-09-01

    Changes in the nature of spin crossover caused by mechanical stressing exerted on the crystalline powders were studied for Fe II(phen) 2(NCS) 2 (phen = 1,10-phenanthroline) and Fe II[HB(pz) 3] 2 (pz = pyrazol-1-yl) by means of a multi-component fitting of the temperature dependence of magnetic susceptibility. The analysis revealed the development and broadening of the ligand field distribution as a consequence of mechanical stressing. This was confirmed by the broadening of Mössbauer and far-infrared spectra.

  20. Structure of a Ca2+-Myristoyl Switch Protein That Controls Activation of a Phosphatidylinositol 4-Kinase in Fission Yeast*

    PubMed Central

    Lim, Sunghyuk; Strahl, Thomas; Thorner, Jeremy; Ames, James B.

    2011-01-01

    Neuronal calcium sensor (NCS) proteins transduce Ca2+ signals and are highly conserved from yeast to humans. We determined NMR structures of the NCS-1 homolog from fission yeast (Ncs1), which activates a phosphatidylinositol 4-kinase. Ncs1 contains an α-NH2-linked myristoyl group on a long N-terminal arm and four EF-hand motifs, three of which bind Ca2+, assembled into a compact structure. In Ca2+-free Ncs1, the N-terminal arm positions the fatty acyl chain inside a cavity near the C terminus. The C14 end of the myristate is surrounded by residues in the protein core, whereas its amide-linked (C1) end is flanked by residues at the protein surface. In Ca2+-bound Ncs1, the myristoyl group is extruded (Ca2+-myristoyl switch), exposing a prominent patch of hydrophobic residues that specifically contact phosphatidylinositol 4-kinase. The location of the buried myristate and structure of Ca2+-free Ncs1 are quite different from those in other NCS proteins. Thus, a unique remodeling of each NCS protein by its myristoyl group, and Ca2+-dependent unmasking of different residues, may explain how each family member recognizes distinct target proteins. PMID:21288895

  1. —Part I. Interaction of Calcium and Copper-Calcium Alloy with Electrolyte

    NASA Astrophysics Data System (ADS)

    Zaikov, Yurii P.; Batukhtin, Victor P.; Shurov, Nikolay I.; Ivanovskii, Leonid E.; Suzdaltsev, Andrey V.

    2014-06-01

    This paper describes the interaction between calcium and molten CaCl2 and the solubility of calcium in this melt, depending on the calcium content in the copper-calcium alloy that comes in contact with the molten CaCl2. The negative influence of the dissolved calcium on the current efficiency was verified. The negative effects of moisture and CaO impurities on the calcium current efficiency were demonstrated. The dependence of the current efficiency and the purity of the metal obtained by the electrolysis conditions were studied in a laboratory electrolyzer (20 to 80 A).

  2. The Role of Calcium in Human Aging

    PubMed Central

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  3. The role of calcium in human aging.

    PubMed

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  4. Rapid screening assay for calcium bioavailability studies

    SciTech Connect

    Luhrsen, K.R.; Hudepohl, G.R.; Smith, K.T.

    1986-03-01

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (/sup 47/Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO/sub 3/. In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the /sup 47/Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison.

  5. Assessment of calcium intake by adolescents

    PubMed Central

    de Oliveira, Cristiane Franco; da Silveira, Carla Rosane; Beghetto, Mariur; de Mello, Paula Daniel; de Mello, Elza Daniel

    2014-01-01

    OBJECTIVE: To evaluate the daily calcium intake of adolescents in schools from Chapecó, Santa Catarina, Southern Brazil, to check if calcium intake is in accordance with the Dietary Reference Intakes (DRI), and to investigate variables associated with daily calcium intake. METHODS: Cross-sectional study approved by the Institutional Review Board and developed in 2010. Students of the 8th grade completed questionnaires with personal data and questions about the calcium-rich foods intake frequency. In order to compare students with adequate (1300mg) or inadequate intake of calcium/day (<1300mg), parametric and nonparametric tests were used. RESULTS: A total of 214 students with a mean age of 14.3±1.0 years were enrolled. The median daily calcium intake was 540mg (interquartile range - IQ: 312-829mg) and only 25 students (11.7%) had calcium intake within the recommendations of the DRI for age. Soft drink consumption ≥3 times/week was associated with a lower intake of calcium. CONCLUSIONS: Few students ingested adequate levels of calcium for the age group. It is necessary to develop a program to encourage a greater intake of calcium-rich foods in adolescence. PMID:25119753

  6. The Role of Calcium in Osteoporosis

    NASA Technical Reports Server (NTRS)

    Arnaud, C. D.; Sanchez, S. D.

    1991-01-01

    Calcium requirements may vary throughout the lifespan. During the growth years and up to age 25 to 30, it is important to maximize dietary intake of calcium to maintain positive calcium balance and achieve peak bone mass, thereby possibly decreasing the risk of fracture when bone is subsequently lost. Calcium intake need not be greater than 800 mg/day during the relatively short period of time between the end of bone building and the onset of bone loss (30 to 40 years). Starting at age 40 to 50, both men and women lose bone slowly, but women lose bone more rapidly around the menopause and for about 10 years after. Intestinal calcium absorption and the ability to adapt to low calcium diets are impaired in many postmenopausal women and elderly persons owing to a suspected functional or absolute decrease in the ability of the kidney to produce 1,25(OH)2D2. The bones then become more and more a source of calcium to maintain critical extracellular fluid calcium levels. Excessive dietary intake of protein and fiber may induce significant negative calcium balance and thus increase dietary calcium requirements. Generally, the strongest risk factors for osteoporosis are uncontrollable (e.g., sex, age, and race) or less controllable (e.g., disease and medications). However, several factors such as diet, physical activity, cigarette smoking, and alcohol use are lifestyle related and can be modified to help reduce the risk of osteoporosis.

  7. The Risks and Benefits of Calcium Supplementation

    PubMed Central

    Kim, Kyoung Min

    2015-01-01

    The association between calcium supplementation and adverse cardiovascular events has recently become a topic of debate due to the publication of two epidemiological studies and one meta-analysis of randomized controlled clinical trials. The reports indicate that there is a significant increase in adverse cardiovascular events following supplementation with calcium; however, a number of experts have raised several issues with these reports such as inconsistencies in attempts to reproduce the findings in other populations and questions concerning the validity of the data due to low compliance, biases in case ascertainment, and/or a lack of adjustment. Additionally, the Auckland Calcium Study, the Women's Health Initiative, and many other studies included in the meta-analysis obtained data from calcium-replete subjects and it is not clear whether the same risk profile would be observed in populations with low calcium intakes. Dietary calcium intake varies widely throughout the world and it is especially low in East Asia, although the risk of cardiovascular events is less prominent in this region. Therefore, clarification is necessary regarding the occurrence of adverse cardiovascular events following calcium supplementation and whether this relationship can be generalized to populations with low calcium intakes. Additionally, the skeletal benefits from calcium supplementation are greater in subjects with low calcium intakes and, therefore, the risk-benefit ratio of calcium supplementation is likely to differ based on the dietary calcium intake and risks of osteoporosis and cardiovascular diseases of various populations. Further studies investigating the risk-benefit profiles of calcium supplementation in various populations are required to develop population-specific guidelines for individuals of different genders, ages, ethnicities, and risk profiles around the world. PMID:25827454

  8. Vasopressin regulates renal calcium excretion in humans

    PubMed Central

    Hanouna, Guillaume; Haymann, Jean-Philippe; Baud, Laurent; Letavernier, Emmanuel

    2015-01-01

    Antidiuretic hormone or arginine vasopressin (AVP) increases water reabsorption in the collecting ducts of the kidney. Three decades ago, experimental models have shown that AVP may increase calcium reabsorption in rat kidney. The objective of this study was to assess whether AVP modulates renal calcium excretion in humans. We analyzed calcium, potassium, and sodium fractional excretion in eight patients affected by insipidus diabetes (nephrogenic or central) under acute vasopressin receptor agonist action and in 10 patients undergoing oral water load test affected or not by inappropriate antidiuretic hormone secretion (SIADH). Synthetic V2 receptor agonist (dDAVP) reduced significantly calcium fractional excretion from 1.71% to 0.58% (P < 0.05) in patients with central diabetes insipidus. In patients with nephrogenic diabetes insipidus (resistant to AVP), calcium fractional excretion did not change significantly after injection (0.48–0.68%, P = NS). In normal subjects undergoing oral water load test, calcium fractional excretion increased significantly from 1.02% to 2.54% (P < 0.05). Patients affected by SIADH had a high calcium fractional excretion at baseline that remained stable during test from 3.30% to 3.33% (P = NS), possibly resulting from a reduced calcium absorption in renal proximal tubule. In both groups, there was a significant correlation between urine output and calcium renal excretion. In humans, dDAVP decreases calcium fractional excretion in the short term. Conversely, water intake, which lowers AVP concentration, increases calcium fractional excretion. The correlation between urine output and calcium excretion suggests that AVP-related antidiuresis increases calcium reabsorption in collecting ducts. PMID:26620256

  9. CatSper and the relationship of hyperactivated motility to intracellular calcium and pH kinetics in equine sperm.

    PubMed

    Loux, Shavahn C; Crawford, Kristin R; Ing, Nancy H; González-Fernández, Lauro; Macías-García, Beatriz; Love, Charles C; Varner, Dickson D; Velez, Isabel C; Choi, Young Ho; Hinrichs, Katrin

    2013-11-01

    In vitro fertilization does not occur readily in the horse. This may be related to failure of equine sperm to initiate hyperactivated motility, as treating with procaine to induce hyperactivation increases fertilization rates. In mice, hyperactivated motility requires a sperm-specific pH-gated calcium channel (CatSper); therefore, we investigated this channel in equine sperm. Motility was assessed by computer-assisted sperm motility analysis and changes in intracellular pH and calcium were assessed using fluorescent probes. Increasing intracellular pH induced a rise in intracellular calcium, which was inhibited by the known CatSper blocker mibefradil, supporting the presence of a pH-gated calcium channel, presumably CatSper. Hyperactivation was associated with moderately increased intracellular pH, but appeared inversely related to increases in intracellular calcium. In calcium-deficient medium, high-pH treatment induced motility loss, consistent with influx of sodium through open CatSper channels in the absence of environmental calcium. However, sperm treated with procaine in calcium-deficient medium both maintained motility and underwent hyperactivation, suggesting that procaine did not act via opening of the CatSper channel. CATSPER1 mRNA was identified in equine sperm by PCR, and CATSPER1 protein was localized to the principal piece on immunocytochemistry. Analysis of the predicted equine CATSPER1 protein revealed species-specific differences in structure in the pH-sensor region. We conclude that the CatSper channel is present in equine sperm but that the relationship of hyperactivated motility to calcium influx is weak. Procaine does not appear to act via CatSper in equine sperm, and its initial hyperactivating action is not dependent upon external calcium influx. PMID:24048572

  10. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    PubMed

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (P<0.01), whereas the aftertaste of commercial tortillas or those fortified with calcium carbonate was preferred over the control (P<0.05). Despite these differences, consumers were equally willing to purchase both fortified and nonfortified tortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  11. Stroma Cell-Derived Factor-1α Signaling Enhances Calcium Transients and Beating Frequency in Rat Neonatal Cardiomyocytes

    PubMed Central

    Hadad, Ielham; Veithen, Alex; Springael, Jean–Yves; Sotiropoulou, Panagiota A.; Mendes Da Costa, Agnès; Miot, Françoise; Naeije, Robert

    2013-01-01

    Stroma cell-derived factor-1α (SDF-1α) is a cardioprotective chemokine, acting through its G-protein coupled receptor CXCR4. In experimental acute myocardial infarction, administration of SDF-1α induces an early improvement of systolic function which is difficult to explain solely by an anti-apoptotic and angiogenic effect. We wondered whether SDF-1α signaling might have direct effects on calcium transients and beating frequency. Primary rat neonatal cardiomyocytes were culture-expanded and characterized by immunofluorescence staining. Calcium sparks were studied by fluorescence microscopy after calcium loading with the Fluo-4 acetoxymethyl ester sensor. The cardiomyocyte enriched cellular suspension expressed troponin I and CXCR4 but was vimentin negative. Addition of SDF-1α in the medium increased cytoplasmic calcium release. The calcium response was completely abolished by using a neutralizing anti-CXCR4 antibody and partially suppressed and delayed by preincubation with an inositol triphosphate receptor (IP3R) blocker, but not with a ryanodine receptor (RyR) antagonist. Calcium fluxes induced by caffeine, a RyR agonist, were decreased by an IP3R blocker. Treatment with forskolin or SDF-1α increased cardiomyocyte beating frequency and their effects were additive. In vivo, treatment with SDF-1α increased left ventricular dP/dtmax. These results suggest that in rat neonatal cardiomyocytes, the SDF-1α/CXCR4 signaling increases calcium transients in an IP3-gated fashion leading to a positive chronotropic and inotropic effect. PMID:23460790

  12. Stroma cell-derived factor-1α signaling enhances calcium transients and beating frequency in rat neonatal cardiomyocytes.

    PubMed

    Hadad, Ielham; Veithen, Alex; Springael, Jean-Yves; Sotiropoulou, Panagiota A; Mendes Da Costa, Agnès; Miot, Françoise; Naeije, Robert; De Deken, Xavier; Entee, Kathleen Mc

    2013-01-01

    Stroma cell-derived factor-1α (SDF-1α) is a cardioprotective chemokine, acting through its G-protein coupled receptor CXCR4. In experimental acute myocardial infarction, administration of SDF-1α induces an early improvement of systolic function which is difficult to explain solely by an anti-apoptotic and angiogenic effect. We wondered whether SDF-1α signaling might have direct effects on calcium transients and beating frequency.Primary rat neonatal cardiomyocytes were culture-expanded and characterized by immunofluorescence staining. Calcium sparks were studied by fluorescence microscopy after calcium loading with the Fluo-4 acetoxymethyl ester sensor. The cardiomyocyte enriched cellular suspension expressed troponin I and CXCR4 but was vimentin negative. Addition of SDF-1α in the medium increased cytoplasmic calcium release. The calcium response was completely abolished by using a neutralizing anti-CXCR4 antibody and partially suppressed and delayed by preincubation with an inositol triphosphate receptor (IP3R) blocker, but not with a ryanodine receptor (RyR) antagonist. Calcium fluxes induced by caffeine, a RyR agonist, were decreased by an IP3R blocker. Treatment with forskolin or SDF-1α increased cardiomyocyte beating frequency and their effects were additive. In vivo, treatment with SDF-1α increased left ventricular dP/dtmax.These results suggest that in rat neonatal cardiomyocytes, the SDF-1α/CXCR4 signaling increases calcium transients in an IP3-gated fashion leading to a positive chronotropic and inotropic effect. PMID:23460790

  13. Extended sensitivity for the calcium selective electrode.

    PubMed

    Morton, R W; Chung, J K; Miller, J L; Charlton, J P; Fager, R S

    1986-09-01

    Sensitivity of calcium-selective electrodes heretofore has been limited to calcium concentrations above 10(-8) M in the absence of competing ions. We describe the use of calcium buffers to stabilize the free calcium in the reference electrode. Electrode calibration is linear to 10(-8) M and is curvilinear to 10(-11) M in the presence of 0.1 M ionic strength. Selectivity with respect to competing cations, magnesium, potassium, sodium, and hydrogen is preserved. Electrode response time is less than 2 s for small changes in calcium activity. Response range is linear over 9 log units of calcium activity. Potential-time stability is less than 10 mV/h at saturation currents. Although the silver-silver chloride terminals are photosensitive throughout the visible and near-ultraviolet regions, housing the reference and indifferent in opaque barrels avoids false photovoltaic response. PMID:3777438

  14. Spinning up the polymorphs of calcium carbonate

    PubMed Central

    Boulos, Ramiz A.; Zhang, Fei; Tjandra, Edwin S.; Martin, Adam D.; Spagnoli, Dino; Raston, Colin L.

    2014-01-01

    Controlling the growth of the polymorphs of calcium carbonate is important in understanding the changing environmental conditions in the oceans. Aragonite is the main polymorph in the inner shells of marine organisms, and can be readily converted to calcite, which is the most stable polymorph of calcium carbonate. Both of these polymorphs are significantly more stable than vaterite, which is the other naturally occurring polymorph of calcium carbonate, and this is reflected in its limited distribution in nature. We have investigated the effect of high shear forces on the phase behaviour of calcium carbonate using a vortex fluidic device (VFD), with experimental parameters varied to explore calcium carbonate mineralisation. Variation of tilt angle, rotation speed and temperature allow for control over the size, shape and phase of the resulting calcium carbonate. PMID:24448077

  15. Binding of calcium and carbonate to polyacrylates.

    PubMed

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  16. STIM and calcium channel complexes in cancer.

    PubMed

    Jardin, Isaac; Rosado, Juan A

    2016-06-01

    The ion Ca(2+) is a ubiquitous second messenger that mediates a variety of cellular functions. Dysfunction of the mechanisms involved in Ca(2+) homeostasis underlies a number of pathological processes, including cancer. Store-operated Ca(2+) entry (SOCE) is a major mechanism for Ca(2+) entry modulated by the intracellular Ca(2+) stores. The Ca(2+)-selective store-operated current (ICRAC) is mediated by the endoplasmic reticulum (ER) Ca(2+) sensor STIM1 and the store-operated Ca(2+) (SOC) channel Orai1, while other non-selective cation currents (ISOC) involves the participation of members of the canonical transient receptor potential (TRPC) channel family, including TRPC1. Distinct isoforms of the key components of SOCE have been described in mammalian cells, STIM1 and 2, Orai1-3 and TRPC1-7. In cancer cells, SOCE has been reported to play an important role in cell cycle progression and proliferation, migration, metastasis and evasion of apoptosis. Changes in the expression of the key elements of SOCE and Ca(2+) homeostasis remodeling have been account to play important roles in the phenotypic changes observed in transformed cells. Despite there are differences in the expression level of the molecular components of SOCE, as well as in the relevance of the STIM, Orai and TRPC isoforms in SOCE and tumorigenesis among cancer cell types, there is a body of evidence supporting an important role for SOCE underlying the phenotypic modifications of cancer cells that propose STIM and the SOC channels as suitable candidate targets for future prognostic or therapeutic strategies. This article is part of a Special Issue entitled: Calcium and Cell Fate. Guest Editors: Jacques Haiech, Claus Heizmann, Joachim Krebs, Thierry Capiod and Olivier Mignen. PMID:26455959

  17. Molecular imaging of in vivo calcium ion expression in area postrema of total sleep deprived rats: Implications for cardiovascular regulation by TOF-SIMS analysis

    NASA Astrophysics Data System (ADS)

    Mai, Fu-Der; Chen, Li-You; Ling, Yong-Chien; Chen, Bo-Jung; Wu, Un-In; Chang, Hung-Ming

    2010-05-01

    Excessive calcium influx in chemosensitive neurons of area postrema (AP) is detrimental for sympathetic activation and participates in the disruption of cardiovascular activities. Since total sleep deprivation (TSD) is a stressful condition known to harm the cardiovascular function, the present study is aimed to determine whether the in vivo calcium expression in AP would significantly alter following TSD by the use of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and calretinin (a specific calcium sensor protein in AP neurons) immunohistochemistry. The results indicated that in normal rats, the calcium intensity was estimated to be 0.5 × 10 5 at m/ z 40.08. However, following TSD, the intensity for calcium ions was greatly increased to 1.2 × 10 5. Molecular imaging revealed that after TSD, various strongly expressed calcium signals were distributed throughout AP with clear identified profiles instead of randomly scattered within this region in normal rats. Immunohistochemical staining corresponded well with ionic image in which a majority of calcium-enriched gathering co-localized with calretinin positive neurons. The functional significance of TSD-induced calcium augmentation was demonstrated by increased heart rate and mean arterial pressure, clinical markers for cardiovascular dysfunction. Considering AP-mediated sympathetic activation is important for cardiovascular regulation, exaggerated calcium influx in AP would render this neurocircuitry more vulnerable to over-excitation, which might serve as the underlying mechanism for the development of TSD-relevant cardiovascular deficiency.

  18. 21 CFR 184.1207 - Calcium lactate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium lactate. 184.1207 Section 184.1207 Food... GRAS § 184.1207 Calcium lactate. (a) Calcium lactate (C6H10CaO6.xH2O, where x is any integer up to 5, CAS Reg. No. 814-80-2) is prepared commercially by the neutralization of lactic acid with...

  19. Gravity, calcium, and bone - Update, 1989

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Morey-Holton, Emily

    1990-01-01

    Recent results obtained on skeletal adaptation, calcium metabolism, and bone browth during short-term flights and ground simulated-microgravity experiments are presented. Results demonstrate that two principal components of calcium metabolism respond within days to changes in body position and to weightlessness: the calcium endocrine system and bone characteristics. Furthermore, results of recent studies imply that bone biomechanics are more severely affected by spaceflight exposures than is the bone mass.

  20. Gravity, Calcium, And Bone: Update, 1989

    NASA Technical Reports Server (NTRS)

    Arnaud, Sara B.; Morey-Holton, Emily

    1992-01-01

    Report reviews short-term flight and ground-based experiments on effects of 1 g and 0 g on skeletal adaptation, calcium metabolism, and growth processes. Results indicate two principal components of calcium metabolism-calcium endocrine system and bone - respond within days to changes in orientation of body in gravitation and to weightlessness. Effects of spaceflight or bed rest on biomechanics of bones more severe than on total body bone mass.