Sample records for hydrated sodium calcium

  1. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729 Section...Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  2. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Sodium calcium aluminosilicate, hydrated. 182...Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  3. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Sodium calcium aluminosilicate, hydrated. 182...Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  4. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729 Section...Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  5. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Sodium calcium aluminosilicate, hydrated. 182...Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  6. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729 Section...Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  7. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Sodium calcium aluminosilicate, hydrated. 182...Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  8. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729 Section...Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  9. 21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729 Section...Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  10. 21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2009-04-01 true Sodium calcium aluminosilicate, hydrated. 182...Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium...

  11. Hydrated sodium calcium aluminosilicate: a high affinity sorbent for aflatoxin.

    PubMed

    Phillips, T D; Kubena, L F; Harvey, R B; Taylor, D R; Heidelbaugh, N D

    1988-02-01

    Aluminas, silicas and aluminosilicates were evaluated for their ability to sorb radiolabeled aflatoxin B1 (AFB1) from aqueous solution (in vitro). Hydrated sodium calcium aluminosilicate (HSCAS) was selected for testing in vivo due to its high affinity for AFB1, because of its stable association with AFB1, and its GRAS (generally recognized as safe) status as an anticaking agent. The HSCAS, when added to the diet of Leghorn and broiler chicks at a level of .5%, significantly diminished the adverse effects of feeding 7.5 mg AFB1/kg of feed. Thus, this agent (and other aluminosilicate congeners) may prove effective in the preventive management of aflatoxicosis. PMID:2837754

  12. Diminution of aflatoxicosis in growing chickens by the dietary addition of a hydrated, sodium calcium aluminosilicate.

    PubMed

    Kubena, L F; Harvey, R B; Phillips, T D; Corrier, D E; Huff, W E

    1990-05-01

    The amelioration of aflatoxicosis in broiler and Leghorn chickens was examined by feeding a hydrated, sodium calcium aluminosilicate (HSCAS) or activated charcoal. In three experiments, HSCAS or activated charcoal at a concentration of .5% of the total diet were incorporated into diets for broiler and Leghorn chicks containing either no added, purified aflatoxin B1 (AFB1), 7.5 mg of AFB1 per kg, or 5 mg of aflatoxin (AF) per kg (produced by Aspergillus parasiticus on rice). Compared to the controls, the AFB1 reduced BW gains at 0 to 3 wk by 21 to 38% in broilers; and the AF reduced BW gains at 0 to 4 wk in Leghorns by 20 percent. The HSCAS significantly diminished the growth-inhibitory effects of AFB1 or of AF on growing chicks by 50 to 67 percent. Feeding 5 mg of AF per kg of diet with or without charcoal to Leghorn chicks caused a significant increase in the relative weights of the liver, kidney, proventriculus, and gizzard as well as significant increases in activity of serum gamma glutamyltransferase; also, significant decreases in the relative bursa weights as well as the concentrations of serum total protein and albumin. With the exception of the relative bursa weights, the toxic effects caused by aflatoxin were prevented or were reduced by adding hydrated, sodium calcium aluminosilicate. These data suggest that HSCAS can modulate the toxicity of AFB1 and AF in the chicken; however, adding activated charcoal to the diet did not appear to have protective properties against the effects of aflatoxin B1 or of aflatoxin. PMID:1973286

  13. Efficacy of hydrated sodium calcium aluminosilicate and activated charcoal in reducing the toxicity of dietary aflatoxin to mink

    Microsoft Academic Search

    R. J. Bonna; R. J. Aulerich; S. J. Bursian; R. H. Poppenga; W. E. Braselton; G. L. Watson

    1991-01-01

    Mink were fed diets that contained 0, 34, or 102 ppb (µg\\/kg) aflatoxins with or without 0.5% hydrated sodium calcium aluminosilicate (HSCAS) and\\/or 1.0% activated charcoal (AC) for 77 days. Consumption of the diet that contained 34 ppb aflatoxins was lethal to 20% of the mink, while 102 ppb dietary aflatoxins resulted in 100% mortality within 53 days. The addition

  14. Hydrated sodium calcium aluminosilicate for reduction of aflatoxin in quails (Coturnix coturnix japonica).

    PubMed

    Sehu, A; Ergün, L; Cakir, S; Ergün, E; Cantekin, Z; Sahin, T; Essiz, D; Sareyyüpo?lu, B; Gürel, Y; Yi?it, Y

    2007-07-01

    The purpose of the present study was to evaluate the toxic effects of aflatoxin (AF) on growth performance and various processing parameters of quails and to determine the preventive efficacy of hydrated sodium calcium aluminosilicate (HSCAS). One hundred and eighty 1-d-old quails of both sexes were randomly divided into 4 experimental groups with 5 replicates and 45 birds following weighing. The experimental design consisted of four dietary treatments: 1) control with 0 mg AF/kg of diet and 0% HSCAS; 2) 0.5% HSCAS; 3) 2.5 mg AF/kg of diet; 4) 2.5 mg AF/kg of diet plus 0.5% HSCAS. The chicks were housed in electrically heated battery cages and exposed to light for 24 h from hatching to 3 weeks of age. Quails consumed the diets and water ad libitum. Body weight (BW) was significantly (p < 0.001) increased by addition of HSCAS to AF diet. The lowest BW gains in groups received AF alone was observed at all periods. The reduction in BW gain caused by 2.5 mg AF/kg of diet was significantly (p < 0.001) diminished by the addition of 0.5% HSCAS to the diet. The addition of HSCAS to the AF diet significantly (p < 0.001) protected against decrease of feed intake at all periods with exception of the first period. None of the treatments altered significantly the feed conversion ratio (FCR). The relative weights of the liver, kidney and spleen were increased in the chickens consuming the AF alone diet. However, light microscopic examination demonstrated the addition of HSCAS to quail feed to partially decrease fat deposition caused by the toxin, and besides, electron microscopic examination of indicated a reorganization in the endoplasmic reticulum and increase in the number of ribosomes and polisomes. Furthermore, the decrease in the antibody titre induced by Newcastle vaccine, due to aflatoxins, was relatively prevented. No significant differences were observed for serum total protein, total cholesterol and glucose levels. The results of indicate that HSCAS is effective in preventing the deleterious effects of AF. PMID:17724933

  15. The calcium silicate hydrates

    Microsoft Academic Search

    I. G. Richardson

    2008-01-01

    This article is concerned with the calcium silicate hydrates, including crystalline minerals and the extremely variable and poorly ordered phase (C-S-H) that is the main binding phase in most concrete. Up-to-date composition and crystal-structure information is tabulated for the most important crystalline calcium (alumino) silicate hydrates and related phases. A number of models for the nanostructure of C-S-H are summarized

  16. Comparison of the sequestering properties of yeast cell wall extract and hydrated sodium calcium aluminosilicate in three in vitro models accounting for the animal physiological bioavailability of zearalenone.

    PubMed

    Yiannikouris, A; Kettunen, H; Apajalahti, J; Pennala, E; Moran, C A

    2013-01-01

    The sequestration/inactivation of the oestrogenic mycotoxin zearalenone (ZEA) by two adsorbents--yeast cell wall extract (YCW) and hydrated sodium calcium aluminosilicate (HSCAS)--was studied in three laboratory models: (1) an in vitro model was adapted from referenced methods to test for the sequestrant sorption capabilities under buffer conditions at two pH values using liquid chromatography coupled to a fluorescence detector for toxin quantification; (2) a second in vitro model was used to evaluate the sequestrant sorption stability according to pH variations and using ³H-labelled ZEA at low toxin concentration; and (3) an original, ex vivo Ussing chamber model was developed to further understand the transfer of ZEA through intestinal tissue and the impact of each sequestrant on the mycotoxin bioavailability of ³H-labelled ZEA. YCW was a more efficient ZEA adsorbent than HSCAS in all three models, except under very acidic conditions (pH 2.5 or 3.0). The Ussing chamber model offered a novel, ex vivo, alternative method for understanding the effect of sequestrant on the bioavailability of ZEA. The results showed that compared with HSCAS, YCW was more efficient in sequestering ZEA and that it reduced the accumulation of ZEA in the intestinal tissue by 40% (p < 0.001). PMID:23844575

  17. Efficiency of hydrated sodium calcium aluminosilicate to ameliorate the adverse effects of graded levels of aflatoxin B1 in broiler chicks.

    PubMed

    Chen, X; Horn, N; Applegate, T J

    2014-08-01

    The objective of this study was to evaluate the efficiency of a hydrated sodium calcium aluminosilicate (HSCAS) adsorbent to ameliorate the adverse effects of 0.5 to 2 mg of aflatoxin B1 (AFB1)/kg in broiler chicks. The study consisted of 8 dietary treatments, including 4 concentrations of AFB1 (0, 0.5, 1, and 2 mg/kg) with or without HSCAS (0.5%) fed to 8 replicate cages per diet (6 males chicks per cage) from 0 to 21 d of age. Cumulative feed intake, BW gain (P < 0.0001), and G:F (P = 0.004) of birds fed the 2 mg of AFB1/kg of diet were significantly lower in comparison with birds fed 0 to 1 mg of AFB1/kg. Relative liver weight was increased in the 2 mg of AFB1/kg group (P < 0.0001). Dietary HSCAS improved cumulative BW gain (main effect P = 0.06), particularly from 14 to 21 d of age (P = 0.037). Dietary HSCAS also reversed the increase in relative liver weight for birds fed AFB1 (P = 0.019). Dietary AFB1 negatively affected major serum parameters (albumin, total protein, globulin, phosphorus, glucose, alkaline phosphatase, and creatine phosphokinase), whereas supplementation with HSCAS partially alleviated the affected serum biochemistry. In addition, serum complement activity and liver gene expression were negatively affected by 2 mg of AFB1/kg. The HSCAS supplement increased the liver expression of catalase and superoxide dismutase (P < 0.05). Results from this study indicate that dietary supplementation with HSCAS can effectively improve BW gain and partially ameliorate aflatoxicosis for broiler chicks fed AFB1-contaminated feeds. PMID:24894529

  18. Hydration of calcium sulfoaluminate cements - Experimental findings and thermodynamic modelling

    SciTech Connect

    Winnefeld, Frank, E-mail: Frank.Winnefeld@empa.c [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, Duebendorf (Switzerland); Lothenbach, Barbara [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Concrete and Construction Chemistry, Duebendorf (Switzerland)

    2010-08-15

    Calcium sulfoaluminate cements (CSA) are a promising low-CO{sub 2} alternative to ordinary Portland cements and are as well of interest concerning their use as binder for waste encapsulation. In this study, the hydration of two CSA cements has been investigated experimentally and by thermodynamic modelling between 1 h and 28 days at w/c ratios of 0.72 and 0.80, respectively. The main hydration product of CSA is ettringite, which precipitates together with amorphous Al(OH){sub 3} until the calcium sulfate is consumed after around 1-2 days of hydration. Afterwards, monosulfate is formed. In the presence of belite, straetlingite occurs as an additional hydration product. The pore solution analysis reveals that straetlingite can bind a part of the potassium ions, which are released by the clinker minerals. The microstructure of both cements is quite dense even after 16 h of hydration, with not much pore space available at a sample age of 28 days. The pore solution of both cements is dominated during the first hours of hydration by potassium, sodium, calcium, aluminium and sulfate; the pH is around 10-11. When the calcium sulfate is depleted, the sulfate concentration drops by a factor of 10. This increases pH to around 12.5-12.8. Based on the experimental data, a thermodynamic hydration model for CSA cements based on cement composition, hydration kinetics of clinker phases and calculations of thermodynamic equilibria by geochemical speciation has been established. The modelled phase development with ongoing hydration agrees well with the experimental findings.

  19. Solubility and structure of calcium silicate hydrate

    Microsoft Academic Search

    Jeffrey J. Chen; Jeffrey J. Thomas; Hal F. W. Taylor; Hamlin M. Jennings

    2004-01-01

    The poorly crystalline calcium silicate hydrate (C-S-H) phases that form near room temperature, which include the technically important C-S-H gel phase formed during the hydration of Portland cement, have a broad similarity to the crystalline minerals tobermorite and jennite, but are characterized by extensive atomic imperfections and structural variations at the nanometer scale. Relationships between the aqueous solubility and chemical

  20. Intrinsic elastic properties of Calcium Silicate Hydrates by nanoindentation

    E-print Network

    Paris-Sud XI, Université de

    1 Intrinsic elastic properties of Calcium Silicate Hydrates by nanoindentation C. Plassard, E. Lesniewska, I. Pochard, A. Nonat University of Bourgogne, Dijon, France Abstract Calcium Silicate Hydrate (C-S-H) nanoparticles were partially recrystallized by Ostwald ripening after long-term equilibrium in calcium hydroxide

  1. Hydration of Portland cement with additions of calcium sulfoaluminates

    SciTech Connect

    Le Saout, Gwenn, E-mail: gwenn.le-saout@mines-ales.fr [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Lothenbach, Barbara [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)] [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Hori, Akihiro [DENKA Chemicals GmbH, Wehrhahn-Center, Cantadorstr. 3, D-40211 Duesseldorf (Germany)] [DENKA Chemicals GmbH, Wehrhahn-Center, Cantadorstr. 3, D-40211 Duesseldorf (Germany); Higuchi, Takayuki [Denki Kagaku Kogyo Kabushiki Kaisha (DENKA), Omi, Itoigawa, Niigata, 949-0393 (Japan)] [Denki Kagaku Kogyo Kabushiki Kaisha (DENKA), Omi, Itoigawa, Niigata, 949-0393 (Japan); Winnefeld, Frank [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)] [Empa, Swiss Federal Laboratories for Materials Science and Technology, Concrete and Construction Chemistry Laboratory, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2013-01-15

    The effect of mineral additions based on calcium aluminates on the hydration mechanism of ordinary Portland cement (OPC) was investigated using isothermal calorimetry, thermal analysis, X-ray diffraction, scanning electron microscopy, solid state nuclear magnetic resonance and pore solution analysis. Results show that the addition of a calcium sulfoaluminate cement (CSA) to the OPC does not affect the hydration mechanism of alite but controls the aluminate dissolution. In the second blend investigated, a rapid setting cement, the amorphous calcium aluminate reacts very fast to ettringite. The release of aluminum ions strongly retards the hydration of alite but the C-S-H has a similar composition as in OPC with no additional Al to Si substitution. As in CSA-OPC, the aluminate hydration is controlled by the availability of sulfates. The coupling of thermodynamic modeling with the kinetic equations predicts the amount of hydrates and pore solution compositions as a function of time and validates the model in these systems.

  2. The hydration of interstitial Portland cement phases in sodium hydroxide and magnesium sulfate solutions

    NASA Astrophysics Data System (ADS)

    Clark, Boyd Arthur

    Formation of sulfoaluminate compounds was investigated by isothermal calorimetry and X-ray diffraction (XRD). Tricalcium aluminate/gypsum mixtures with a molar ratio of 1:1 sulfate-to-aluminate were hydrated at constant temperatures from 30 to 90°C; in de-ionized water, in 200mM and in 500mM sodium hydroxide (NaOH) solutions. Hydration in de-ionized water produced ettringite and monosulfate as the dominant crystalline phases, regardless of temperature. Complex assemblages of phases formed in 200mM and 500mM sodium hydroxide including ettringite, monosulfate and U-phase, at all temperatures. Hydration of monosulfate and gypsum was also carried out at constant temperatures from 30° to 80°C using de-ionized water and 0.2M, 0.5M, and 1.0M sodium hydroxide (NaOH) solutions. Ettringite was found to be the dominant crystalline phase over the entire temperature range and at all sodium hydroxide concentrations. A sodium-substituted monosulfate phase was formed as a hydration product in the 1.0M sodium hydroxide solution regardless of temperature. Sulfoaluminate compounds formed by tricalcium aluminate hydration in magnesium sulfate solution were investigated by isothermal calorimetry, XRD, and scanning electron microscopy (SEM). Hydration was carried out in 0.5, 1.0 and 3.0M magnesium sulfate solutions and isothermally at temperatures from 30 to 80°C. Monosulfate, ettringite, gypsum and a hydrogarnet phase (Ca3Al2O6·6H2O) were all observed as hydration products. Monosulfate and hydrogarnet were the only phases observed for hydration in 0.5 and 1.0M magnesium sulfate solutions. Ettringite was the dominant crystalline phase after hydration in 3.0M solution, regardless of temperature. To investigate the rate of hydration, reactions at 60°C in 3.0M magnesium sulfate solution were quenched after 26 minutes, 73 minutes, 2.5 hours and 12 hours to establish the evolution of hydrated phases. Depending on hydration times ettringite, monosulfate, gypsum, hydrogarnet and residual tricalcium aluminate were observed. No crystalline magnesium-rich phases were detected by XRD. The products formed by hydration of tetracalcium aluminoferrite (Ca 2AlFeO5) and magnesium sulfate solutions were investigated by isothermal calorimetry, XRD and SEM analyses. Hydration reactions were carried out isothermally at temperatures from 25 to 80°C in 0.25M, 0.5M, 1.0M, 2.0M, and 3.0M magnesium sulfate solutions. Gypsum was the initial hydration product in all magnesium sulfate concentrations and was the only crystalline hydration product in 2.0M and 3.0M magnesium sulfate solutions. Monosulfate was the dominant crystalline phase produced over the entire temperature range when hydration was carried out in magnesium sulfate concentrations between 0.25M and 1.0M. No crystalline phases incorporating iron were observed regardless of magnesium sulfate concentration or temperature. Hydration in 1.0M MgSO 4 solution was more extensively investigated at 50°C. SEM observations indicated gypsum formed initially, consisting of fine particles (<5 mum). Complex phase assemblages including gypsum, ettringite, and monosulfate were present at intermediate times. Monosulfate was the final crystalline hydration product. Amorphous solids produced include a calcium/iron-rich gel and a magnesium/aluminum/sulfate-rich phase. The calcium/iron-rich gel is the only iron-rich phase observed in the hydrated phase assemblage.

  3. Sodium-calcium interactions under salinity stress 205 SODIUM-CALCIUM INTERACTIONS UNDER SALINITY STRESS

    E-print Network

    Cramer, Grant R.

    Sodium-calcium interactions under salinity stress 205 CHAPTER 10 SODIUM-CALCIUM INTERACTIONS UNDER SALINITY STRESS G.R. CRAMER Department of Biochemistry, Mail Stop 200 University of Nevada, Reno, NV 89557 USA cramer@unr.edu Abstract There are a wide range of responses of plants to salinity which involve

  4. 21 CFR 180.37 - Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...true Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin. 180...37 Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin. ...additives saccharin, ammonium saccharin, calcium saccharin, and sodium...

  5. Dynamic behavior of hydration water in calcium-silicate-hydrate gel: A quasielastic neutron scattering spectroscopy investigation

    E-print Network

    Li, Hua

    The translational dynamics of hydration water confined in calcium-silicate-hydrate (C-S-H) gel was studied by quasielastic neutron scattering spectroscopy in the temperature range from 280 to 230 K. The stretch exponent ...

  6. A nanoscale numerical model of calcium silicate hydrate P.C. Fonseca a,

    E-print Network

    Andrade, Jose

    A nanoscale numerical model of calcium silicate hydrate P.C. Fonseca a, , H.M. Jennings b , J-density and high-density calcium­ silicate­hydrate (C­S­H) gel phases in cement paste. Generated using reserved. 1. Introduction Calcium silicate hydrate (C­S­H)1 is the primary binding phase in cement

  7. 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)

  8. Experimental investigation of calcium silicate hydrate (CSH) nucleation

    Microsoft Academic Search

    S. Garrault-Gauffinet; A Nonat

    1999-01-01

    Due to the importance of calcium silicate hydrate (C-S-H) in cement chemistry, its nucleation mode and parameters influencing it were investigated. It has been observed that the C-S-H nucleation follows the general laws governing the nucleation. The degree of supersaturation has been found to be the main parameter controlling homogeneous nucleation rates. The lime concentration in solution, well known to

  9. The role of calcium ions and lignosulphonate plasticiser in the hydration of cement

    SciTech Connect

    Grierson, L.H.; Knight, J.C.; Maharaj, R

    2005-04-01

    Experiments involving equilibrium dialysis, conductivity, X-ray diffraction analysis (XRD), differential thermal analysis (DTA) and isothermal titration calorimetry (ITC) have been carried out to investigate the role of calcium ions and polymeric plasticisers in cement/admixture hydration. Results from a study of lignosulphonic acid, sodium salt, acetate as a plasticiser shows that a plasticiser has dual role; one mainly as a kinetic inhibitor (poison) in cement hydration mechanism and the other as a dispersant. Evidence of a weak Ca{sup 2+} binding to lignosulphonate sulphonic moieties was found at low ionic strengths of 0.1 M using ITC. No evidence of formal Ca{sup 2+} binding to lignosulphonate sulphonic acid moieties was found using equilibrium dialysis at higher ionic strength of 1 M (ionic strengths of 0.4 M are typically found in Portland cement pore solution), as is often suggested in cement/admixture literature.

  10. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 2014-04-01 false Feed-grade calcium stearate and sodium stearate. 573.280...Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate. Feed-grade calcium stearate and sodium stearate may be...

  11. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Feed-grade calcium stearate and sodium stearate. 573.280...Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate. Feed-grade calcium stearate and sodium stearate may be...

  12. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Feed-grade calcium stearate and sodium stearate. 573.280...Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate. Feed-grade calcium stearate and sodium stearate may be...

  13. 21 CFR 573.280 - Feed-grade calcium stearate and sodium stearate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 2011-04-01 false Feed-grade calcium stearate and sodium stearate. 573.280...Additive Listing § 573.280 Feed-grade calcium stearate and sodium stearate. Feed-grade calcium stearate and sodium stearate may be...

  14. Order and disorder in calcium–silicate–hydrate

    SciTech Connect

    Bauchy, M., E-mail: bauchy@mit.edu [Concrete Sustainability Hub, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); MIT-CNRS Joint Laboratory at Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Qomi, M. J. Abdolhosseini; Ulm, F.-J. [Concrete Sustainability Hub, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Pellenq, R. J.-M. [Concrete Sustainability Hub, Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); MIT-CNRS Joint Laboratory at Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States); Centre Interdisciplinaire des Nanosciences de Marseille, CNRS and Aix-Marseille University, Campus de Luminy, 13288 Marseille Cedex 09 (France)

    2014-06-07

    Despite advances in the characterization and modeling of cement hydrates, the atomic order in Calcium–Silicate–Hydrate (C–S–H), the binding phase of cement, remains an open question. Indeed, in contrast to the former crystalline model, recent molecular models suggest that the nanoscale structure of C–S–H is amorphous. To elucidate this issue, we analyzed the structure of a realistic simulated model of C–S–H, and compared the latter to crystalline tobermorite, a natural analogue of C–S–H, and to an artificial ideal glass. The results clearly indicate that C–S–H appears as amorphous, when averaged on all atoms. However, an analysis of the order around each atomic species reveals that its structure shows an intermediate degree of order, retaining some characteristics of the crystal while acquiring an overall glass-like disorder. Thanks to a detailed quantification of order and disorder, we show that, while C–S–H retains some signatures of a tobermorite-like layered structure, hydrated species are completely amorphous.

  15. Uptake of chloride and carbonate ions by calcium monosulfoaluminate hydrate

    SciTech Connect

    Mesbah, Adel [Commissariat a l'Energie Atomique et aux Energies Alternatives, CEA DEN/DTCD/SPDE, F-30207 Bagnols sur Ceze (France); Clermont Universite, ENSCCF, Laboratoire des Materiaux Inorganiques, BP 10448, F-63000 Clermont-Ferrand (France); Cau-dit-Coumes, Celine, E-mail: celine.cau-dit-coumes@cea.fr [Commissariat a l'Energie Atomique et aux Energies Alternatives, CEA DEN/DTCD/SPDE, F-30207 Bagnols sur Ceze (France); Renaudin, Guillaume [Clermont Universite, ENSCCF, Laboratoire des Materiaux Inorganiques, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6002, F-63177 Aubiere (France); Frizon, Fabien [Commissariat a l'Energie Atomique et aux Energies Alternatives, CEA DEN/DTCD/SPDE, F-30207 Bagnols sur Ceze (France); Leroux, Fabrice [Clermont Universite, Universite Blaise Pascal, Laboratoire des Materiaux Inorganiques, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6002, F-63177 Aubiere (France)

    2012-08-15

    Decommissioning of old nuclear reactors may produce waste streams containing chlorides and carbonates, including radioactive {sup 36}Cl{sup -} and {sup 14}CO{sub 3}{sup 2-}. Their insolubilization by calcium monosulfoaluminate hydrate was investigated. Carbonates were readily depleted from the solution, giving at thermodynamic equilibrium monocarboaluminate, monocarboaluminate + calcite, or calcite only, depending on the initial ratio between the anion and calcium monosulfoaluminate hydrate. Chloride ions reacted more slowly and were precipitated as Kuzel's salt, Kuzel's and Friedel's salts, or Friedel's salt only. Rietveld refinement of X-Ray powder diffraction patterns was successfully used to quantify the phase distributions, which were compared to thermodynamic calculations. Moreover, analysing the lattice parameters of Kuzel's salt as a function of its chloride content showed the occurrence of a restricted solid solution towards the sulfate side with general formula 3CaO{center_dot}Al{sub 2}O{sub 3}{center_dot}xCaCl{sub 2}{center_dot}(1 - x)CaSO{sub 4}{center_dot}(12 - 2x){center_dot}H{sub 2}O (0.36 {<=} x {<=} 0.50).

  16. Sodium-calcium exchange and calcium-calcium exchange in internally dialyzed squid giant axons

    Microsoft Academic Search

    M. P. Blaustein; J. M. Russell

    1975-01-01

    Summary The influx and efflux of calcium (as45Ca) and influx of sodium (as24Na) were studied in internally dialyzed squid giant axons. The axons were poisoned with cyanide and ATP was omitted from the dialysis fluid. The internal ionized Ca2+ concentration ([Ca2+]i) was controlled with Ca-EGTA buffers. With [Ca2+]i>0.5 µm,45Ca efflux was largely dependent upon external Na and Ca. The Na0-dependent

  17. Calcium and sodium bentonite for hydraulic containment applications

    Microsoft Academic Search

    Mark H. Gleason; David E. Daniel; Gerald R. Eykholt

    1997-01-01

    The hydraulic conductivity of calcium and sodium bentonites was investigated for sand-bentonite mixtures, a thin bentonite layer simulating a geosynthetic clay liner (GCL), and bentonite-cement mixtures simulating backfill for a vertical cutoff wall. The permeant liquids were tap water and distilled water containing 0.25 M calcium chloride. In general, the hydraulic performance of calcium bentonite was not significantly better than

  18. Hydration studies of calcium sulfoaluminate cements blended with fly ash

    SciTech Connect

    García-Maté, M.; De la Torre, A.G. [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga (Spain)] [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga (Spain); León-Reina, L. [Servicios Centrales de Apoyo a la Investigación, Universidad de Málaga, 29071 Málaga (Spain)] [Servicios Centrales de Apoyo a la Investigación, Universidad de Málaga, 29071 Málaga (Spain); Aranda, M.A.G. [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga (Spain) [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga (Spain); CELLS-Alba synchrotron, Carretera BP 1413, Km. 3.3, E-08290 Cerdanyola, Barcelona (Spain); Santacruz, I., E-mail: isantacruz@uma.es [Departamento de Química Inorgánica, Cristalografía y Mineralogía, Universidad de Málaga, 29071 Málaga (Spain)

    2013-12-15

    The main objective of this work is to study the hydration and properties of calcium sulfoaluminate cement pastes blended with fly ash (FA) and the corresponding mortars at different hydration ages. Laboratory X-ray powder diffraction, rheological studies, thermal analysis, porosimetry and compressive strength measurements were performed. The analysis of the diffraction data by Rietveld method allowed quantifying crystalline phases and overall amorphous contents. The studied parameters were: i) FA content, 0, 15 and 30 wt.%; and ii) water addition, water-to-CSA mass ratio (w/CSA = 0.50 and 0.65), and water-to-binder mass ratio (w/b = 0.50). Finally, compressive strengths after 6 months of 0 and 15 wt.% FA [w/CSA = 0.50] mortars were similar: 73 ± 2 and 72 ± 3 MPa, respectively. This is justified by the filler effect of the FA as no strong evidences of reactivity of FA with CSA were observed. These results support the partial substitution of CSA cements with FA with the economic and environmental benefits.

  19. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  20. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  1. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  2. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  3. 21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification...polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive is a device...

  4. Structural relationship and desolvation behavior of cromolyn, cefazolin and fenoprofen sodium hydrates.

    PubMed

    Stephenson, G A; Diseroad, B A

    2000-04-01

    The hydrated crystal structures of cromolyn, cefazolin, and fenoprofen sodium salts are reported. The former two compounds are non-stoichiometric hydrates, whereas the fenoprofen lattice maintains its stoichiometry over a broad range of relative humidity. The relationship between composition, lattice parameters, and relative humidity is studied using a combination of moisture sorption isotherms and variable humidity X-ray powder diffraction. The dehydration properties of the sodium salts are related to the ion coordination and hydrogen bonding of the water molecules in the structures. Anisotropic lattice contraction is observed during dehydration of the cromolyn and cefazolin sodium and is related to the closeness of intermolecular contacts in the hydrated structures. PMID:10767566

  5. A model for the microstructure of calcium silicate hydrate in cement paste

    Microsoft Academic Search

    Hamlin M. Jennings

    2000-01-01

    A model is proposed for the structure of calcium silicate hydrate (C-S-H) as it is formed during the hydration of Portland cement. One purpose of the model is to move toward an ability to evaluate the microstructure quantitatively, so that it can be related to properties on the one hand and processing on the other hand. It is a hypothesis

  6. Sodium sulfate heptahydrate: a synchrotron energy-dispersive diffraction study of an elusive metastable hydrated salt 

    E-print Network

    Hamilton, Andrea; Hall, Christopher

    2008-01-01

    We describe an unusual application of synchrotron energy-dispersive diffraction with hard X-rays to obtain structural information on metastable sodium sulfate heptahydrate. This hydrate was often mentioned in nineteenth ...

  7. The influence of calcium on sodium efflux in squid axons

    PubMed Central

    Baker, P. F.; Blaustein, M. P.; Hodgkin, A. L.; Steinhardt, R. A.

    1969-01-01

    1. Previous work has shown that the sodium efflux from the axons of Loligo forbesi increases when external sodium is replaced by lithium. 2. The increase in efflux in lithium was unaffected by ouabain but was abolished by removal of external calcium; in these respects it differed from the potassium-dependent sodium efflux which was abolished by ouabain but not reduced by removal of external calcium. 3. Strontium but not magnesium could replace calcium in activating the ouabain-insensitive sodium efflux; lanthanum had an inhibitory effect. 4. Replacing all the external NaCl by choline chloride or dextrose gave a rise in Na efflux which was abolished by ouabain but not by removal of external calcium. 5. The rise in Na efflux resulting from partial replacement of NaCl by dextrose or choline chloride consisted of two components one of which was ouabain-insensitive and calcium-dependent and the other was inhibited by ouabain but calcium-insensitive. 6. The ouabain-insensitive component of the Na efflux was activated by low concentrations of Na, Li or K but inhibited by high concentrations of Na and to a lesser extent Li. The inhibiting effect of high Na was of the kind expected if these ions displace calcium from an external site. 7. The ouabain-insensitive component of the Na efflux was abolished by cyanide, had a Q10 of 2·7; and was roughly proportional to [Na]i2. It was much more variable in magnitude than the ouabain-sensitive, potassium-dependent component of the sodium efflux. 8. The calcium influx increased five to fortyfold when external NaCl was replaced by LiCl or dextrose, the increase for Li being larger than the increase for dextrose. 9. The calcium influx from Na, Li or dextrose sea water was increased three to tenfold by increasing the internal Na about fourfold. 10. The experiments provide evidence for a coupling between an inward movement of calcium and an outward movement of sodium. PMID:5764407

  8. Pressure induced reactions amongst calcium aluminate hydrate phases

    SciTech Connect

    Moon, Ju-hyuk [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States); Oh, Jae Eun [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan Metropolitan City, 689-798 (Korea, Republic of); Balonis, Magdalena; Glasser, Fredrik P. [Department of Chemistry, Meston Building, University of Aberdeen, Aberdeen, AB24 3UE Scotland (United Kingdom); Clark, Simon M. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA20015 (United States); Department of Earth and Planetary Sciences, University of California, Berkeley, CA94720 (United States); Monteiro, Paulo J.M., E-mail: monteiro@berkeley.ed [Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 (United States)

    2011-06-15

    The compressibilities of two AFm phases (straetlingite and calcium hemicarboaluminate hydrate) and hydrogarnet were obtained up to 5 GPa by using synchrotron high-pressure X-ray powder diffraction with a diamond anvil cell. The AFm phases show abrupt volume contraction regardless of the molecular size of the pressure-transmitting media. This volume discontinuity could be associated to a structural transition or to the movement of the weakly bound interlayer water molecules in the AFm structure. The experimental results seem to indicate that the pressure-induced dehydration is the dominant mechanism especially with hygroscopic pressure medium. The Birch-Murnaghan equation of state was used to compute the bulk modulus of the minerals. Due to the discontinuity in the pressure-volume diagram, a two stage bulk modulus of each AFm phase was calculated. The abnormal volume compressibility for the AFm phases caused a significant change to their bulk modulus. The reliability of this experiment is verified by comparing the bulk modulus of hydrogarnet with previous studies.

  9. Zeta-Potential Study of Calcium Silicate Hydrates Interacting with Alkaline Cations

    Microsoft Academic Search

    Hélène Viallis-Terrisse; André Nonat; Jean-Claude Petit

    2001-01-01

    An investigation into the interaction between alkaline cations and calcium silicate hydrates (CSH) was conducted by electrokinetic measurements, which provided information on the nature of the interface between the solid and its equilibrium solution. Calcium constitutes for the CSH surface a potential-determining cation. A model of the CSH surface could be proposed, accounting for the experimental evolution of the CSH

  10. RLE DES IONS SODIUM DANS L'ABSORPTION GASTRIQUE DU CALCIUM CHEZ LES RUMINANTS

    E-print Network

    Paris-Sud XI, Université de

    of a calcium salt (chloride, carbonate or phosphate) and sodium chloride. The concentration of calciumR�LE DES IONS SODIUM DANS L'ABSORPTION GASTRIQUE DU CALCIUM CHEZ LES RUMINANTS D. TIMET D. EMANOVI, Université de Zagreb, B. P. 190, YU-41001 Zagreb, Yougoslavie Summary ROLE OF SODIUM IONS IN GASTRIC

  11. Hydration Status Regulates Sodium Flux and Inflammatory Pathways through Epithelial Sodium Channel (ENaC) in the Skin.

    PubMed

    Xu, Wei; Hong, Seok Jong; Zeitchek, Michael; Cooper, Garry; Jia, Shengxian; Xie, Ping; Qureshi, Hannan A; Zhong, Aimei; Porterfield, Marshall D; Galiano, Robert D; Surmeier, D James; Mustoe, Thomas A

    2015-03-01

    Although it is known that the inflammatory response that results from disruption of epithelial barrier function after injury results in excessive scarring, the upstream signals remain unknown. It has also been observed that epithelial disruption results in reduced hydration status and that the use of occlusive dressings that prevent water loss from wounds decreases scar formation. We hypothesized that hydration status changes sodium homeostasis and induces sodium flux in keratinocytes, which result in activation of pathways responsible for keratinocyte-fibroblast signaling and ultimately lead to activation of fibroblasts. Here, we demonstrate that perturbations in epithelial barrier function lead to increased sodium flux in keratinocytes. We identified that sodium flux in keratinocytes is mediated by epithelial sodium channels (ENaCs) and causes increased secretion of proinflammatory cytokines, which activate fibroblast via the cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) pathway. Similar changes in signal transduction and sodium flux occur by increased sodium concentration, which simulates reduced hydration, in the media in epithelial cultures or human ex vivo skin cultures. Blockade of ENaC, prostaglandin synthesis, or PGE2 receptors all reduce markers of fibroblast activation and collagen synthesis. In addition, employing a validated in vivo excessive scar model in the rabbit ear, we demonstrate that utilization of either an ENaC blocker or a COX-2 inhibitor results in a marked reduction in scarring. Other experiments demonstrate that the activation of COX-2 in response to increased sodium flux is mediated through the PIK3/Akt pathway. Our results indicate that ENaC responds to small changes in sodium concentration with inflammatory mediators and suggest that the ENaC pathway is a potential target for a strategy to prevent fibrosis. PMID:25371970

  12. Composition and density of nanoscale calcium–silicate–hydrate in cement

    Microsoft Academic Search

    Jeffrey J. Thomas; Hamlin M. Jennings; Andrew J. Allen

    2007-01-01

    Although Portland cement concrete is the world’s most widely used manufactured material, basic questions persist regarding its internal structure and water content, and their effect on concrete behaviour. Here, for the first time without recourse to drying methods, we measure the composition and solid density of the principal binding reaction product of cement hydration, calcium–silicate–hydrate (C–S–H) gel, one of the

  13. Accelerating effects of colloidal nano-silica for beneficial calcium–silicate–hydrate formation in cement

    Microsoft Academic Search

    J. Bjornstrom; A. Martinelli; A. Matic; L. Borjesson; I. Panas

    2004-01-01

    The hydration process of Ca3SiO5 (C3S) cement is investigated, and accelerating effects of adding colloidal silica (CS) are established. CS accelerates dissolution of the C3S phase, and renders a more rapid formation of the calcium–silicate–hydrate (C–S–H) binding phase. The role of water is demonstrated. Water evaporation correlates with the appearance of a sharp IR band at 3650 cm?1 signifying non-hydrogen

  14. 29Si MAS NMR study of the structure of calcium silicate hydrate

    Microsoft Academic Search

    Xiandong Cong; R. James Kirkpatrick

    1996-01-01

    This paper presents the results of a comprehensive investigation of single-phase calcium silicate hydrate (C?S?H) with known compositions using the combined capabilities of 29Si magic angle spinning (MAS) NMR, powder X-ray diffraction (XRD), and chemical analysis of the solution and solid. C?S?H gels with C\\/S ratios ranging from 0.4 to 1.85 have been synthesized by hydration of highly reactive ?-C2S

  15. Formation of Hydroxyl Groups at Calcium-Silicate-Hydrate (C-S-H): Coexistence of Ca-OH and Si-OH on Wollastonite(001)

    E-print Network

    Schmidt, Wolf Gero

    Formation of Hydroxyl Groups at Calcium-Silicate-Hydrate (C-S-H): Coexistence of Ca-OH and Si understanding of the concrete interface formed with water is essential. Calcium-silicate-hydrate (C-S-H) phases

  16. Mass density and water content of saturated never-dried calcium silicate hydrates.

    PubMed

    da Silva, Julio C; Trtik, Pavel; Diaz, Ana; Holler, Mirko; Guizar-Sicairos, Manuel; Raabe, Jörg; Bunk, Oliver; Menzel, Andreas

    2015-04-01

    Calcium silicate hydrates (C-S-H) are the most abundant hydration products in ordinary Portland cement paste. Yet, despite the critical role they play in determining mechanical and transport properties, there is still a debate about their density and exact composition. Here, the site-specific mass density and composition of C-S-H in hydrated cement paste are determined with nanoscale resolution in a nondestructive approach. We used ptychographic X-ray computed tomography in order to determine spatially resolved mass density and water content of the C-S-H within the microstructure of the cement paste. Our findings indicate that the C-S-H at the border of hydrated alite particles possibly have a higher density than the apparent inner-product C-S-H, which is contrary to the common expectations from previous works on hydrated cement paste. PMID:25794183

  17. Sodium entry through endothelial store-operated calcium entry channels: regulation by Orai1.

    PubMed

    Xu, Ningyong; Cioffi, Donna L; Alexeyev, Mikhail; Rich, Thomas C; Stevens, Troy

    2015-02-15

    Orai1 interacts with transient receptor potential protein of the canonical subfamily (TRPC4) and contributes to calcium selectivity of the endothelial cell store-operated calcium entry current (ISOC). Orai1 silencing increases sodium permeability and decreases membrane-associated calcium, although it is not known whether Orai1 is an important determinant of cytosolic sodium transitions. We test the hypothesis that, upon activation of store-operated calcium entry channels, Orai1 is a critical determinant of cytosolic sodium transitions. Activation of store-operated calcium entry channels transiently increased cytosolic calcium and sodium, characteristic of release from an intracellular store. The sodium response occurred more abruptly and returned to baseline more rapidly than did the transient calcium rise. Extracellular choline substitution for sodium did not inhibit the response, although 2-aminoethoxydiphenyl borate and YM-58483 reduced it by ?50%. After this transient response, cytosolic sodium continued to increase due to influx through activated store-operated calcium entry channels. The magnitude of this sustained increase in cytosolic sodium was greater when experiments were conducted in low extracellular calcium and when Orai1 expression was silenced; these two interventions were not additive, suggesting a common mechanism. 2-Aminoethoxydiphenyl borate and YM-58483 inhibited the sustained increase in cytosolic sodium, only in the presence of Orai1. These studies demonstrate that sodium permeates activated store-operated calcium entry channels, resulting in an increase in cytosolic sodium; the magnitude of this response is determined by Orai1. PMID:25428882

  18. Silicate Anion Structural Change in Calcium Silicate Hydrate Gel on Dissolution of Hydrated Cement

    Microsoft Academic Search

    Kazuko HAGA; Masahito SHIBATA; Michihiko HIRONAGA; Satoru TANAKA; Shinya NAGASAKI

    2002-01-01

    High pH conditions of aqueous solutions in a radioactive waste repository can be brought about by dissolution of cementitious materials. In order to clarify the mechanisms involved in maintaining this high pH for long time, we investigated the dissolution phenomena of OPC hydrate. In the present research, leaching tests on powdered cement hydrates were conducted by changing the ratio of

  19. Investigation of the surface structure and elastic properties of calcium silicate hydrates at the nanoscale

    Microsoft Academic Search

    Cédric Plassard; Eric Lesniewska; Isabelle Pochard; André Nonat

    2004-01-01

    This work is the first step towards the understanding of the structure of calcium silicate hydrate (C–S–H), the main constituent of cement paste, at the nanoscale. The first demonstration of atomic-resolution imaging of the (C–S–H) surface with an atomic force microscope (AFM) was performed.C–S–H nanoparticles (60×30×5nm3) were partially recrystallized by Ostwald ripening after long-term equilibrium in saturated calcium hydroxide solution

  20. Potassium bicarbonate, but not sodium bicarbonate, reduces urinary calcium excretion and improves calcium balance in healthy men

    Microsoft Academic Search

    Jacob Lemann; Richard W Gray; Joan A Pleuss

    1989-01-01

    Potassium bicarbonate, but not sodium bicarbonate, reduces urinary calcium excretion and improves calcium balance in healthy men. Previous studies demonstrated that the administration of NaHCO3 or sodium citrate had either only a small effect to reduce urinary Ca excretion or no effect, but that potassium citrate significantly reduced urinary Ca excretion. In order to further evaluate and compare the effects

  1. Accelerated growth of calcium silicate hydrates: Experiments and simulations

    SciTech Connect

    Nicoleau, Luc, E-mail: luc.nicoleau@basf.com

    2011-12-15

    Despite the usefulness of isothermal calorimetry in cement analytics, without any further computations this brings only little information on the nucleation and growth of hydrates. A model originally developed by Garrault et al. is used in this study in order to simulate hydration curves of cement obtained by calorimetry with different known hardening accelerators. The limited basis set of parameters used in this model, having a physical or chemical significance, is valuable for a better understanding of mechanisms underlying in the acceleration of C-S-H precipitation. Alite hydration in presence of four different types of hardening accelerators was investigated. It is evidenced that each accelerator type plays a specific role on one or several growth parameters and that the model may support the development of new accelerators. Those simulations supported by experimental observations enable us to follow the formation of the C-S-H layer around grains and to extract interesting information on its apparent permeability.

  2. Microanalysis of calcium silicate hydrate gel formed within a geopolymeric binder

    Microsoft Academic Search

    C. K. Yip; J. S. J. van Deventer

    2003-01-01

    It is possible to have geopolymeric gel and calcium silicate hydrate (CSH) gel forming simultaneously within a single system. Scanning electron microscopy was employed in studying the morphology and elemental composition of the two phases. The elemental composition within the different phases was consistent. However, CSH gel formed in such system had a significantly lower Ca\\/Si ratio than the CSH

  3. The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation

    Microsoft Academic Search

    C. K. Yip; G. C. Lukey; J. S. J. van. Deventer

    2005-01-01

    Scanning electron microscopy was used to study the effects of the addition of ground granulated blast furnace slag (GGBFS) on the microstructure and mechanical properties of metakaolin (MK) based geopolymers. It was found that it is possible to have geopolymeric gel and calcium silicate hydrate (CSH) gel forming simultaneously within a single binder. The coexistence of these two phases is

  4. Accepted by the Journal of Building Physics (2007) Microstructure and Thermal Conductivity of Hydrated Calcium Silicate Board Materials

    E-print Network

    Bentz, Dale P.

    of Hydrated Calcium Silicate Board Materials Chi T. Do, Dale P. Bentz1 , and Paul E. Stutzman Building and pore size are examined for two calcium silicate boards of different densities. Thermal conductivities; radiation; thermal conductivity. Introduction In recent years, a variety of low-density calcium silicate

  5. Hydration and strength development of binder based on high-calcium oil shale fly ash

    SciTech Connect

    Freidin, C. [Ben-Gurion Univ. of the Negev, Sede-Boqer (Israel)] [Ben-Gurion Univ. of the Negev, Sede-Boqer (Israel)

    1998-06-01

    The properties of high-calcium oil shale fly ash and low-calcium coal fly ash, which are produced in Israeli power stations, were investigated. High-calcium oil shale fly ash was found to contain a great amount of CaO{sub free} and SO{sub 3} in the form of lime and anhydrite. Mixtures of high-calcium oil shale fly ash and low-calcium coal fly ash, termed fly ash binder, were shown to cure and have improved strength. The influence of the composition and curing conditions on the compressive strength of fly ash binders was examined. The microstructure and the composition of fly ash binder after curing and long-term exposure in moist air, water and open air conditions were studied. It was determined that ettringite is the main variable in the strength and durability of cured systems. The positive effect of calcium silicate hydrates, CSH, which are formed by interaction of high-calcium oil shale fly ash and low-calcium coal fly ash components, on the carbonation and dehydration resistance of fly ash binder in open air is pronounced. It was concluded that high-calcium oil shale fly ash with high CaO{sub free} and SO{sub 3} content can be used as a binder for building products.

  6. Crystal chemistry and structure refinement of five hydrated calcium borates

    USGS Publications Warehouse

    Clark, J.R.; Appleman, D.E.; Christ, C.L.

    1964-01-01

    The crystal structures of the five known members of the series Ca2B6O11??xH2O (x = 1, 5, 5, 7, 9, and 13) have been refined by full-matrix least-squares techniques, yielding bond distances and angles with standard errors of less than 0??01 A?? and 0??5??, respectively. The results illustrate the crystal chemical principles that govern the structures of hydrated borate compounds. The importance of hydrogen bonding in the ferroelectric transition of colemanite is confirmed by more accurate proton assignments. ?? 1964.

  7. Atomistic structure of sodium and calcium silicate intergranular films in alumina

    E-print Network

    Garofalini, Stephen H.

    Atomistic structure of sodium and calcium silicate intergranular films in alumina David A. Litton. The results were compared to previous simulations of calcium silicate and sol-gel silica IGF's in contact March 1998; accepted 21 October 1998) Sodium silicate intergranular films (IGF) in contact

  8. A model for two types of calcium silicate hydrate in the microstructure of Portland cement pastes

    Microsoft Academic Search

    Paul D Tennis; Hamlin M Jennings

    2000-01-01

    A new physical basis for a previously published model for the structure of calcium silicate hydrate (C-S-H) as measured by nitrogen sorption is described. This refined model provides a method of predicting the density, the nitrogen accessible gel porosity, and associated surface area of C-S-H in Portland cement pastes. The basis for the model is that C-S-H forms as one

  9. The effects of calcium and magnesium on sodium fluxes through gills of Carassius auratus, L

    PubMed Central

    Cuthbert, A. W.; Maetz, J.

    1972-01-01

    1. Removal of calcium from Carassius either with chelating agents or by adaptation to deionized water increased sodium influx through the gills twofold. 2. Treatment of fish with chelating agents increased sodium outflux, whereas adaptation to deionized water reduced sodium outflux. The effects on outflux do not appear to result from calcium removal. 3. Addition of calcium (2-20 mM) reversed the effects on influx of chelating agents and of adaptation to deionized water. 4. Magnesium (2-10 mM) was without significant effect on sodium influx, but increased the outflow in fish adapted to deionized water. PMID:4622716

  10. Relevance of Rheological Properties of Sodium Alginate in Solution to Calcium Alginate Gel Properties

    Microsoft Academic Search

    Shao Fu; Ankur Thacker; Diana M. Sperger; Riccardo L. Boni; Ira S. Buckner; Sachin Velankar; Eric J. Munson; Lawrence H. Block

    2011-01-01

    The purpose of this study is to determine whether sodium alginate solutions’ rheological parameters are meaningful relative\\u000a to sodium alginate’s use in the formulation of calcium alginate gels. Calcium alginate gels were prepared from six different\\u000a grades of sodium alginate (FMC Biopolymer), one of which was available in ten batches. Cylindrical gel samples were prepared\\u000a from each of the gels

  11. Effects of metabolic acidosis and alkalosis on sodium and calcium transport in the dog kidney.

    PubMed

    Sutton, R A; Wong, N L; Dirks, J H

    1979-05-01

    Clearance and micropuncture studies have been performed in dogs to examine the effects of acute and chronic metabolic acidosis and acute alkalosis on tubular sodium and calcium transport. Acute metabolic acidosis, induced by the infusion of hydrochloric acid, decreased proximal fluid reabsorption and increased the fractional delivery of sodium and calcium to the distal tubule, but not to the final urine. In comparison with normal dogs, dogs with chronic metabolic acidosis (induced by feeding ammonium chloride) showed an increase in proximal fluid reabsorption and a dissociation of calcium from sodium reabsorption more distally, leading to an increased delivery of calcium relative to sodium at the distal tubule and in the final urine. The infusion of sodium bicarbonate to correct chronic metabolic acidosis, both in intact and thyroparathyroidectomized (TPTX) dogs, reduced proximal fluid reabsorption and caused a selective enhancement of calcium reabsorption relative to sodium in the more distal nephron, resulting in a reversal of the dissociation observed in acidosis, both at the distal tubule and in the final urine. By contrastin fusion of sodium chloride in parathyroid-intact acidotic dogs did not reduce proximal fluid reabsorption or enhance tubular calcium reabsorption. In nonacidotic dogs, both intact and TPTX, infusion of sodium bicarconate to induce acute alkalosis resulted in selhese data demonstrate the presence of a component of tubular calcium reabsorption situated beyond the proximal tubule, which is inhibited by chronic (but not acute) metabolic acidosis and enhanced by metabolic alkalosis (or bicarbonate infusion) independently of parathyroid hormone. PMID:480784

  12. Novel attempts for the synthesis of calcium sulfate hydrates in calcium chloride solutions under atmospheric conditions

    Microsoft Academic Search

    Jen-Chang Yang; Hong-Da Wu; Nai-Chia Teng; Dian-Yu Ji; Sheng-Yang Lee

    The medical grade calcium sulfate is widely used in clinical applications for treating bone defects. A high-purity and predictable calcium sulfate (CS) synthesis process is desirable in the medical industry. The objective of this study was to develop a one-pot method for the direct preparation of calcium sulfate hemihydrates (CSHs; such as the ?- and ?-forms) in a CaCl2 solution.

  13. Santaclaraite, a new calcium-manganese silicate hydrate from California.

    USGS Publications Warehouse

    Erd, R.C.; Ohashi, Y.

    1984-01-01

    Santaclaraite, ideally CaMn4(Si5O14(OH))(OH).H2O, occurs as pink and tan veins and masses in Franciscan chert in the Diablo Range, Santa Clara and Stanislaus counties, California. It is associated with four unidentified Mn silicates, Mn-howieite, quartz, braunite, calcite, rhodochrosite, kutnahorite, baryte, harmotome, chalcopyrite and native copper. Santaclaraite is triclinic, space group B1, a 15.633(1), b 7.603(1) , c 12.003(1) A, alpha 109.71(1)o, beta 88.61(1)o, gamma 99.95(1) o, V 1322.0(3) A3; Z = 4. The strongest lines of the X-ray pattern are 7.04(100), 3.003(84), 3.152(80), 7.69(63), 3.847(57) A. Crystals are lamellar to prismatic (flattened on (100)), with good cleavage on (100) and (010); H. 61/2 Dcalc. 3.398 g/cm3, Dmeas. 3.31 (+ or -0.01); optically biaxial negative, alpha 1.681, beta 1.696, gamma 1.708 (all + or - 0.002), 2Valpha 83 (+ or -1)o. Although chemically a hydrated rhodonite, santaclaraite dehydrates to Mn-bustamite at approx 550oC (in air) . Santaclaraite is a five-tetrahedral-repeat single-chain silicate and has structural affinities with rhodonite, nambulite, marsturite, babingtonite and inesite.-J.A.Z.

  14. Crystallographic basis for calcium regulation of sodium channels.

    PubMed

    Sarhan, Maen F; Tung, Ching-Chieh; Van Petegem, Filip; Ahern, Christopher A

    2012-02-28

    Voltage-gated sodium channels underlie the rapid regenerative upstroke of action potentials and are modulated by cytoplasmic calcium ions through a poorly understood mechanism. We describe the 1.35 Å crystal structure of Ca(2+)-bound calmodulin (Ca(2+)/CaM) in complex with the inactivation gate (DIII-IV linker) of the cardiac sodium channel (Na(V)1.5). The complex harbors the positions of five disease mutations involved with long Q-T type 3 and Brugada syndromes. In conjunction with isothermal titration calorimetry, we identify unique inactivation-gate mutations that enhance or diminish Ca(2+)/CaM binding, which, in turn, sensitize or abolish Ca(2+) regulation of full-length channels in electrophysiological experiments. Additional biochemical experiments support a model whereby a single Ca(2+)/CaM bridges the C-terminal IQ motif to the DIII-IV linker via individual N and C lobes, respectively. The data suggest that Ca(2+)/CaM destabilizes binding of the inactivation gate to its receptor, thus biasing inactivation toward more depolarized potentials. PMID:22331908

  15. Composition and density of nanoscale calcium?silicate?hydrate in cement

    SciTech Connect

    Allen, Andrew J.; Thomas, Jeffrey J.; Jennings, Hamlin M. (NIST); (NWU)

    2009-08-26

    Although Portland cement concrete is the world's most widely used manufactured material, basic questions persist regarding its internal structure and water content, and their effect on concrete behaviour. Here, for the first time without recourse to drying methods, we measure the composition and solid density of the principal binding reaction product of cement hydration, calcium-silicate-hydrate (C-S-H) gel, one of the most complex of all gels. We also quantify a nanoscale calcium hydroxide phase that coexists with C-S-H gel. By combining small-angle neutron and X-ray scattering data, and by exploiting the hydrogen/deuterium neutron isotope effect both in water and methanol, we determine the mean formula and mass density of the nanoscale C-S-H gel particles in hydrating cement. We show that the formula, (CaO){sub 1.7}(SiO{sub 2})(H{sub 2}O){sub 1.80}, and density, 2.604 Mg m{sup -3}, differ from previous values for C-S-H gel, associated with specific drying conditions. Whereas previous studies have classified water within C-S-H gel by how tightly it is bound, in this study we classify water by its location - with implications for defining the chemically active (C-S-H) surface area within cement, and for predicting concrete properties.

  16. Impact of hydration state and molecular oxygen on the chemical stability of levothyroxine sodium.

    PubMed

    Hamad, Mazen Lee; Engen, William; Morris, Kenneth R

    2015-05-01

    Levothyroxine sodium is an important medication used primarily for treating patients with hypothyroidism. Levothyroxine sodium tablets have been recalled many times since their 1955 introduction to the US market. These recalls resulted from the failure of lots to meet their content uniformity and potency specifications. The purpose of this study is to test the hypothesis that the chemical stability of levothyroxine sodium pentahydrate is compromised upon exposing the dehydrated substance to molecular oxygen. The impact of temperature, oxygen and humidity storage conditions on the stability of solid-state levothyroxine sodium was examined. After exposure to these storage conditions for selected periods of time, high performance liquid chromatography (HPLC) was used to quantify the formation of impurities. The results showed that levothyroxine sodium samples degraded significantly over a 32-day test period when subjected to dry conditions in the presence of molecular oxygen. However, dehydrated samples remained stable when oxygen was removed from the storage chamber. Furthermore, hydrated samples were stable in the presence of oxygen and in the absence of oxygen. These results reveal conditions that will degrade levothyroxine sodium pentahydrate and elucidate measures that can be taken to stabilize the drug substance. PMID:24295156

  17. The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation

    SciTech Connect

    Yip, C.K. [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Lukey, G.C. [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia); Deventer, J.S.J. van [Department of Chemical and Biomolecular Engineering, University of Melbourne, Victoria 3010 (Australia)]. E-mail: jannie@unimelb.edu.au

    2005-09-01

    Scanning electron microscopy was used to study the effects of the addition of ground granulated blast furnace slag (GGBFS) on the microstructure and mechanical properties of metakaolin (MK) based geopolymers. It was found that it is possible to have geopolymeric gel and calcium silicate hydrate (CSH) gel forming simultaneously within a single binder. The coexistence of these two phases is dependent on the alkalinity of the alkali activator and the MK / GGBFS mass ratio. It has been found that the formation of CSH gel together with the geopolymeric gel occurs only in a system at low alkalinity. In the presence of high concentrations of NaOH (> 7.5 M), the geopolymeric gel is the predominant phase formed with small calcium precipitates scattered within the binder. The coexistence of the two phases is not observed unless a substantial amount of a reactive calcium source is present initially. It is thought that voids and pores within the geopolymeric binder become filled with the CSH gel. This helps to bridge the gaps between the different hydrated phases and unreacted particles; thereby resulting in the observed increase in mechanical strength for these binders.

  18. A thermodynamic model of dissolution and precipitation of calcium silicate hydrates

    SciTech Connect

    Sugiyama, Daisuke [Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1, Iwado-kita, Komae-shi, Tokyo 201-8511 (Japan)]. E-mail: daisukes@criepi.denken.or.jp; Fujita, Tomonari [Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry (CRIEPI), 2-11-1, Iwado-kita, Komae-shi, Tokyo 201-8511 (Japan)

    2006-02-15

    A thermodynamic incongruent dissolution/precipitation model of calcium silicate hydrate (C-S-H) is proposed, assuming a binary nonideal solid solution of Ca(OH){sub 2} and SiO{sub 2}. Using this model, both dissolution and precipitation of the C-S-H phase, with a continuous change in the Ca / Si ratio of the solid phase, can be predicted. The notable features of the model are its good continuity and simplicity so that calculation can be easily compiled in a calculation code. A series of experiments were carried out. C-S-H precipitates were prepared using two techniques: precipitation by contacting Ca(OH){sub 2} solution with C-S-H gel and hydrolysis in a mixture of Ca and Si solutions. The equilibria in these experiments were predicted well by the proposed model. A calculation using the model also predicted well the dissolution of ordinary Portland cement hydrate with water exchange.

  19. On the nature of structural disorder in calcium silicate hydrates with a calcium/silicon ratio similar to tobermorite

    SciTech Connect

    Grangeon, Sylvain, E-mail: S.Grangeon@brgm.fr [BRGM, 3, Avenue Claude Guillemin, 45060 Orléans Cedex 2 (France)] [BRGM, 3, Avenue Claude Guillemin, 45060 Orléans Cedex 2 (France); Claret, Francis; Lerouge, Catherine [BRGM, 3, Avenue Claude Guillemin, 45060 Orléans Cedex 2 (France)] [BRGM, 3, Avenue Claude Guillemin, 45060 Orléans Cedex 2 (France); Warmont, Fabienne [CRMD, UMR 6619 – CNRS, 1b rue de la férollerie, 45071 Orléans Cedex 2 (France)] [CRMD, UMR 6619 – CNRS, 1b rue de la férollerie, 45071 Orléans Cedex 2 (France); Sato, Tsutomu; Anraku, Sohtaro [Laboratory of Environmental Geology, Research Group of Geoenvironmental/Engineering Division of Solid Waste, Resources and Geoenvironmental/Engineering Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Sapporo 060-8628 (Japan)] [Laboratory of Environmental Geology, Research Group of Geoenvironmental/Engineering Division of Solid Waste, Resources and Geoenvironmental/Engineering Graduate School of Engineering, Hokkaido University, Kita 13 Nishi 8, Sapporo 060-8628 (Japan); Numako, Chiya [Faculty of Integrated Arts and Sciences, The University of Tokushima, 1-1, Minami-Josanjima, Tokushima, 770-8502 (Japan)] [Faculty of Integrated Arts and Sciences, The University of Tokushima, 1-1, Minami-Josanjima, Tokushima, 770-8502 (Japan); Linard, Yannick [ANDRA, Centre de Meuse/Haute Marne, 55290 Bure (France)] [ANDRA, Centre de Meuse/Haute Marne, 55290 Bure (France); Lanson, Bruno [ISTerre, Grenoble University, CNRS, F-38041 Grenoble (France)] [ISTerre, Grenoble University, CNRS, F-38041 Grenoble (France)

    2013-10-15

    Four calcium silicate hydrates (C-S-H) with structural calcium/silicon (Ca/Si) ratios ranging from 0.82 ± 0.02 to 0.87 ± 0.02 were synthesized at room temperature, 50, 80, and 110 °C. Their structure was elucidated by collating information from electron probe micro-analysis, transmission electron microscopy, extended X-ray absorption fine structure spectroscopy, and powder X-ray diffraction (XRD). A modeling approach specific to defective minerals was used because sample turbostratism prevented analysis using usual XRD refinement techniques (e.g. Rietveld analysis). It is shown that C-S-H with Ca/Si ratio of ? 0.8 are structurally similar to nano-crystalline turbostratic tobermorite, a naturally occurring mineral. Their structure thus consists of sheets of calcium atoms in 7-fold coordination, covered by ribbons of silicon tetrahedra with a dreierketten (wollastonite-like) organization. In these silicate ribbons, 0.42 Si per bridging tetrahedron are missing. Random stacking faults occur systematically between successive layers (turbostratic stacking). Layer-to-layer distance is equal to 11.34 Å. Crystallites have a mean size of 10 nm in the a–b plane, and a mean number of 2.6–2.9 layers stacked coherently along the c* axis.

  20. Preparation and properties of calcium silicate hydrate-poly(vinyl alcohol) nanocomposite materials

    Microsoft Academic Search

    S. C. Mojumdar; L. Raki

    2005-01-01

    Summary  A series of calcium silicate hydrate (C-S-H)-polymer nanocomposite (C-S-HPN) materials were prepared by incorporating poly(vinyl\\u000a alcohol) (PVA) into the inorganic layers of C-S-H during precipitation of quasicrystalline C-S-H from aqueous solution. The\\u000a as synthesized C-S-HPN materials were characterized by Fourier-transform infrared photoacoustic (FTIRPAS) spectroscopy, X-ray\\u000a diffraction (XRD), scanning electron microscopy\\/energy dispersed spectroscopy (SEM\\/EDS), thermogravimetric analysis (TG),\\u000a differential thermogravimetry (DTG) and

  1. Thermal,spectral and AFM studies of calcium silicate hydrate-polymer nanocompositematerial

    Microsoft Academic Search

    S. C. Mojumdar; L. Raki; N. Mathis; K. Schimdt; S. Lang

    2006-01-01

    A non-ionic polymer (poly(vinyl\\u000a alcohol) (PVA)) has been incorporated into the inorganic layers of calcium\\u000a silicate hydrate (C–S–H) during precipitation of quasicrystalline\\u000a C–S–H from aqueous solution. C–S–H and a C–S–H-polymer\\u000a nanocomposite (C–S–HPN) material were synthesized and characterized\\u000a by X-ray fluorescence (XRF), energy dispersive spectroscopy (EDS), 29Si\\u000a magic angle spinning nuclear magnetic resonance (29Si\\u000a MAS NMR) and 13C cross-polarization nuclear magnetic

  2. Behavioral/Systems/Cognitive Sodium and Calcium Current-Mediated Pacemaker Neurons

    E-print Network

    Del Negro, Christopher A.

    Behavioral/Systems/Cognitive Sodium and Calcium Current-Mediated Pacemaker Neurons and RespiratoryICAN enhanceneuronalexcitabilityandpromoterhythmogenesis,eveniftheirmagnitudeisinsufficienttosupport bursting-pacemaker activity in individual neurons excitability, which is inconsistent with a pacemaker-essential mechanism of respiratory rhythmogenesis

  3. Structure of the calcium pyrophosphate monohydrate phase (Ca2P2O7·H2O): towards understanding the dehydration process in calcium pyrophosphate hydrates.

    PubMed

    Gras, Pierre; Ratel-Ramond, Nicolas; Teychéné, Sébastien; Rey, Christian; Elkaim, Erik; Biscans, Béatrice; Sarda, Stéphanie; Combes, Christèle

    2014-09-01

    Calcium pyrophosphate hydrate (CPP, Ca(2)P(2)O(7) · nH2O) and calcium orthophosphate compounds (including apatite, octacalcium phosphate etc.) are among the most prevalent pathological calcifications in joints. Even though only two dihydrated forms of CPP (CPPD) have been detected in vivo (monoclinic and triclinic CPPD), investigations of other hydrated forms such as tetrahydrated or amorphous CPP are relevant to a further understanding of the physicochemistry of those phases of biological interest. The synthesis of single crystals of calcium pyrophosphate monohydrate (CPPM; Ca(2)P(2)O(7) · H2O) by diffusion in silica gel at ambient temperature and the structural analysis of this phase are reported in this paper. Complementarily, data from synchrotron X-ray diffraction on a CPPM powder sample have been fitted to the crystal parameters. Finally, the relationship between the resolved structure for the CPPM phase and the structure of the tetrahydrated calcium pyrophosphate ? phase (CPPT-?) is discussed. PMID:25186358

  4. Calcium transient and sodium-calcium exchange current in human versus rabbit sinoatrial node pacemaker cells.

    PubMed

    Verkerk, Arie O; van Borren, Marcel M G J; Wilders, Ronald

    2013-01-01

    There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN) cells, focusing on the relative importance of the "membrane clock" and the "Ca(2+) clock" in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, I f , which is also known as the "funny current" or "pacemaker current," or the Ca(2+) clock-driven sodium-calcium exchange current, I NaCa, is the main contributor to diastolic depolarization. In our contribution to this journal's "Special Issue on Cardiac Electrophysiology," we present a numerical reconstruction of I f and I NaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, I f , and intracellular calcium concentration ([Ca(2+)] i ) that we have acquired from these cells. The human SAN pacemaker cells have a smaller I f , a weaker [Ca(2+)] i transient, and a smaller I NaCa than the rabbit cells. However, when compared to the diastolic net membrane current, I NaCa is of similar size in human and rabbit SAN pacemaker cells, whereas I f is smaller in human than in rabbit cells. PMID:23606816

  5. Effect of some inorganic admixtures on the formation and properties of calcium silicate hydrates produced in hydrothermal conditions

    Microsoft Academic Search

    Wies?awa Nocu?-Wczelik

    1997-01-01

    Hydrated calcium silicates have been synthesized at 200 °C under saturated steam pressure, giving materials consisting of ill crystallized calcium silicate hydrates, formed as an initial product and\\/or more crystalline forms. Three series of samples having different CaOSiO2 ratios and doped with inorganic compounds such as CaCl2, AlCl3, CrCl3, Na2CrO4, NaOH and Al(OH)3 were produced. The phase composition of the

  6. X-ray photoelectron spectroscopic investigation of nanocrystalline calcium silicate hydrates synthesised by reactive milling

    SciTech Connect

    Black, Leon [Forschungszentrum Karlsruhe GmbH, Institut fuer Technische Chemie, Bereich Thermische Abfallbehandlung (ITC-TAB), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany) and Materials and Engineering Research Institute, Sheffield Hallam University, Howard Street, Sheffield, S1 1WB (United Kingdom)]. E-mail: l.black@shu.ac.uk; Garbev, Krassimir [Forschungszentrum Karlsruhe GmbH, Institut fuer Technische Chemie, Bereich Thermische Abfallbehandlung (ITC-TAB), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Beuchle, Guenter [Forschungszentrum Karlsruhe GmbH, Institut fuer Technische Chemie, Bereich Thermische Abfallbehandlung (ITC-TAB), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Stemmermann, Peter [Forschungszentrum Karlsruhe GmbH, Institut fuer Technische Chemie, Bereich Thermische Abfallbehandlung (ITC-TAB), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Schild, Dieter [Forschungszentrum Karlsruhe GmbH, Institut fuer Nukleare Entsorgung (INE), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2006-06-15

    X-ray photoelectron spectroscopy (XPS) has been used to analyse a series of mechanochemically synthesised, nanocrystalline calcium silicate hydrates (C-S-H). The samples, with Ca/Si ratios of 0.2 to 1.5, showed structural features of C-S-H(I). XPS analysis revealed changes in the extent of silicate polymerisation. Si 2p, Ca 2p and O 1s spectra showed that, unlike for the crystalline calcium silicate hydrate phases studied previously, there was no evidence of silicate sheets (Q{sup 3}) at low Ca/Si ratios. Si 2p and O 1s spectra indicated silicate depolymerisation, expressed by decreasing silicate chain length, with increasing C/S. In all spectra, peak narrowing was observed with increasing Ca/Si, indicating increased structural ordering. The rapid changes of the slope of FWHM of Si 2p, {delta} {sub Ca-Si} and {delta} {sub NBO-BO} as function of C/S ratio indicated a possible miscibility gap in the C-S-H-solid solution series between C/S 5/6 and 1. The modified Auger parameter ({alpha}') of nanocrystalline C-S-H decreased with increasing silicate polymerisation, a trend already observed studying crystalline C-S-H. Absolute values of {alpha}' were shifted about - 0.7 eV with respect to crystalline phases of equal C/S ratio, due to reduced crystallinity.

  7. Interplay between sodium and calcium dynamics in granule cell presynaptic terminals.

    PubMed Central

    Regehr, W G

    1997-01-01

    Fluorescent indicators were used to detect stimulus-evoked changes in presynaptic levels of intracellular sodium (Na(i)) and calcium (Ca(i)) in granule cell parallel fibers in brain slices from rat cerebellum. Ca(i) increased during stimulation, and three exponentials were needed to approximate its return to prestimulus levels. Ca(i) decayed to approximately 10% of peak levels with tau approximately 100 ms, to approximately 1% of peak values with tau approximately 6 s, and then returned to prestimulus levels with tau approximately 1-2 min. After stimulation, Na(i) accumulated in two phases; one rapid, the other continuing for several hundred milliseconds. The return of Na(i) to prestimulus levels was well approximated by a double exponential decay with time constants of 6-17 s and 2-3 min. Manipulations that prevented calcium entry eliminated both the slow component of sodium entry and the rapid component of Na(i) decay. Reductions of extracellular sodium slowed the rapid phase of Ca(i) decay. These Ca(i) and Na(i) transients were well described by a model in which the plasma membrane of presynaptic boutons contained both a sodium/calcium exchanger and a calcium ATPase (Ca-ATPase). According to this model, immediately after stimulation the sodium/calcium exchanger removes calcium from the terminal more rapidly than does the Ca-ATPase. Eventually, the large concomitant sodium influx brings the exchanger into steady-state, leaving only the Ca-ATPase to remove calcium. This perturbs the equilibrium of the sodium/calcium exchanger, which opposes the Ca-ATPase, leading to a slow return of Ca(i) and Na(i) to resting levels. PMID:9370441

  8. Effects of anesthetics pentobarbital sodium and chloral hydrate on urine proteome

    PubMed Central

    Zhao, Mindi; Li, Xundou; Li, Menglin

    2015-01-01

    Urine can be a better source than blood for biomarker discovery since it accumulates many changes. The urine proteome is susceptible to many factors, including anesthesia. Pentobarbital sodium and chloral hydrate are commonly used anesthetics in animal experiments. This study demonstrated the effects of these two anesthetics on the rat urine proteome using liquid chromatography–tandem mass spectrometry (LC-MS/MS). With anesthesia, the urinary protein-to-creatinine ratio of all rats increased twofold. The relative abundance of 22 and 23 urinary proteins were changed with pentobarbital sodium or chloral hydrate anesthesia, respectively, as determined by label-free quantification. Among these changed proteins, fifteen had been considered as candidate biomarkers such as uromodulin, and sixteen had been considered stable in healthy human urine, which are more likely to be considered as potential biomarkers when changed, such as transferrin. The pattern of changed urinary proteins provides clues to the discovery of urinary proteins regulatory mechanisms. When determining a candidate biomarker, anesthetic-related effects can be excluded from future biomarker discovery studies. Since anesthetics take effects via nervous system, this study is the first to provide clues that the protein handling function of the kidney may possibly be regulated by the nervous system. PMID:25789206

  9. Intake of protein, calcium and sodium in public child day care centers

    PubMed Central

    Longo-Silva, Giovana; Toloni, Maysa Helena de A.; de Menezes, Risia Cristina E.; Temteo, Tatiane Leocádio; Oliveira, Maria Alice A.; Asakura, Leiko; Costa, Emília Chagas; Taddei, José Augusto de A. C.

    2014-01-01

    OBJECTIVE: To assess calcium, protein and sodium intake, of children that attend public day-care centers and to compare it with the recommended one. METHODS: Cross-sectional descriptive study in seven public day care centers of São Paulo city, Southeast Brazil, which enrolled 366 children between 12 and 36 months of age. The data collection occurred between September and December 2010. Each day care center was evaluated for three non-consecutive days, totaling 42 days and 210 meals. Dietary intake was assessed by a direct food weighing method. For the nutritional calculation, DietWin(r) Profissional 2.0 was used, and the adequacy was calculated according to the recommendations of the National School Feeding Program for energy, protein, calcium and sodium. The calcium/protein relation was also calculated, as well as calcium density (mg/1,000kcal). RESULTS: The energy (406.4kcal), protein (18.2g) and calcium (207.6mg) consumption did not reach the recommended values ??in all the evaluated day care centers. Sodium intake exceeded up to three times the recommendation. The calcium/protein ratio of 11.7mg/g was less than the adequate one (20mg/g). CONCLUSIONS: There was inadequacy of calcium, protein and sodium dietary intake, in children attending public day-care centers. PMID:25119750

  10. Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aluminate by {sup 27}Al and {sup 29}Si MAS NMR spectroscopy

    SciTech Connect

    Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Joergen

    2004-05-01

    The effects of hydrating a white Portland cement (wPc) in 0.30 and 0.50 M solutions of sodium aluminate (NaAlO{sub 2}) at 5 and 20 deg. C are investigated by {sup 27}Al and {sup 29}Si magic-angle spinning (MAS) NMR spectroscopy. It is demonstrated that NaAlO{sub 2} accelerates the hydration of alite and belite and results in calcium-silicate-hydrate (C-S-H) phases with longer average chain lengths of SiO{sub 4}/AlO{sub 4} tetrahedra. The C-S-H phases are investigated in detail and it is shown that the Al/Si ratio for the chains of tetrahedra is quite constant during the time studied for the hydration (6 h to 2 years) but increases for higher concentration of the NaAlO{sub 2} solution. The average chain lengths of 'pure' silicate and SiO{sub 4}/AlO{sub 4} tetrahedra demonstrate that Al acts as a linker for the silicate chains, thereby producing aluminosilicate chains with longer average chain lengths. Finally, it is shown that NaAlO{sub 2} reduces the quantity of ettringite and results in larger quantities of monosulfate and a calcium aluminate hydrate phase.

  11. Acidosis and hypercalciuria: renal mechanisms affecting calcium, magnesium and sodium excretion in the sheep.

    PubMed

    Stacy, B D; Wilson, B W

    1970-10-01

    1. Observations were made on the excretion of calcium and magnesium by the sheep's kidney following manipulation of the acid-base status.2. Intravascular administration of a synthetic solution resembling saliva abolished the naturally occurring acidosis in sheep during feeding, and it also prevented the normal onset of post-prandial hypercalciuria and hypermagnesiuria.3. Non-respiratory acidosis (induced by infusion of hydrochloric acid) and respiratory acidosis arising from inhalation of 6% (v/v) CO(2) in air both caused an acute increase in calcium excretion.4. Measurement of filtered loads showed that feeding exerted an effect on the functional characteristics of the sheep's kidney. The renal clearances of calcium and magnesium increased, whereas sodium clearance decreased.5. Experimental conditions were arranged so that variations in acid-base status could be imposed at a time when the filtered load of calcium was declining.6. With hydrochloric acid-acidosis the renal excretion of calcium increased, despite a steady fall in the filtered load. With sodium bicarbonate alkalosis, the filtered load and the renal excretion of calcium decreased in unison.7. These variations in calcium excretion were not accompanied by corresponding changes in the excretion of sodium.8. It is concluded that the renal tubules in the sheep are sensitive to acid-base status and that they respond to a lowering of the blood pH by decreasing the tubular reabsorption of filtered calcium. PMID:5499811

  12. Selective removal of radio-sodium from neutron-activated materials by retention on hydrated antimony pentoxide

    Microsoft Academic Search

    F. Girardi; E. Sabbioni

    1968-01-01

    A new method is presented to remove sodium interferences from neutron-activated materials. The method is based on passage\\u000a of the samples, dissolved in a concentrated acid solution on a column of hydrated antimony pentoxide (HAP). The retention\\u000a is quantitative with a maximum capacity of 31 mg Na\\/g HAP. Only tantalum, in addition to sodium, was retained by HAP out of

  13. Study on Immobilization Activated Sludge by Polyvinyl Alcohol-sodium Alginate - Calcium Nitrate in Domestic Sewage Treatment

    Microsoft Academic Search

    Nie Qian; Jian Peichao; Liu Zhibin; Gu Fang

    2010-01-01

    Preparation conditions of immobilization activated sludge were studied with polyvinyl alcohol-sodium alginate as carrier and calcium nitrate as cross linking agent. Physical properties and removal effect of immobilization activated sludge were also investigated, where cross linking agent was boric acid, calcium chloride, calcium nitrate, respectively. The effect of sewage treatment was compared with activated sludge cross optimum linker calcium nitrate

  14. Preparation,thermal, spectral and microscopic studies of calcium silicate hydrate–poly(acrylicacid) nanocomposite materials

    Microsoft Academic Search

    S. C. Mojumdar; L. Raki

    2006-01-01

    A series of calcium silicate hydrate (C–S–H)-polymer nanocomposite\\u000a (C–S–HPN) materials were prepared by incorporating poly(acrylic\\u000a acid) (PAA) into the inorganic layers of C–S–H during precipitation\\u000a of quasicrystalline C–S–H from aqueous solution. The as-synthesized\\u000a C–S–HPN materials were characterized by X-ray fluorescence (XRF),\\u000a X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy\\u000a (SEM-EDS), Fourier-transform infrared (FTIR) spectroscopy, thermogravimetric\\u000a analysis (TG) and differential scanning

  15. Hydration kinetics of CA{sub 2} and CA-Investigations performed on a synthetic calcium aluminate cement

    SciTech Connect

    Klaus, S.R., E-mail: klaus@geol.uni-erlangen.de; Neubauer, J., E-mail: juergen.neubauer@gzn.uni-erlangen.de; Goetz-Neunhoeffer, F., E-mail: friedlinde.goetz@gzn.uni-erlangen.de

    2013-01-15

    Much is already known about the hydration of monocalcium aluminate (CA) in calcium aluminate cements (CACs). CA{sub 2} is known to be weakly hydraulic. Therefore, the hydration kinetics of CA{sub 2} were not of as great interest as those of the hydration of CAC. We were able to show that the hydration of CA{sub 2} begins as soon as the hydration rate of CA has reached its maximum and the first precipitation of C{sub 2}AH{sub 8} has started. The hydration of different CA/CA{sub 2} ratios was analyzed by the G-factor quantification. The individual contributions of the phases CA and CA{sub 2} to the heat flow were calculated based on the amounts dissolved by applying thermodynamic data. The heat flow as calculated from XRD data was then compared with the measured heat flow. It obtained a good consistency between the two. The very pronounced influence of CA{sub 2} during hydration of CAC can be clearly demonstrated.

  16. Interaction of Nanostructured Calcium Silicate Hydrate with Ibuprofen Drug Molecules: X-ray Absorption Near Edge Structure (XANES) Study at the Ca, Si and O K-edge

    NASA Astrophysics Data System (ADS)

    Guo, X. X.; Sham, T. K.; Zhu, Y. J.; Hu, Y. F.

    2013-04-01

    Mesoporous calcium silicate hydrate (CSH) nanostructure has been proven to be bioactive and biocompatible, and has a bright future in the application of bone treatment among other applications. X-ray absorption near edge structure (XANES) is a powerful tool for the study of the interactions of calcium silicate hydrates with drug molecules because it is element specific and it probes the unoccupied electronic states. Herein, we report the use of the calcium, silicon and oxygen K-edge XANES spectroscopy to identify how drug molecules interact with different groups in calcium silicate hydrate mesoporous nano-carriers with different morphologies. Significant changes are observed in XANES spectra after drug loading into the calcium silicate hydrate system, especially at the Si and O K-edge. The implications of these findings are discussed.

  17. Inhibitive effect of calcium gluconate and sodium molybdate on carbon steel

    Microsoft Academic Search

    S. M. A. Shibli; V. Anitha Kumary

    2004-01-01

    There is an increasing demand for eco-friendly inhibitors for use in cooling water systems. Both calcium gluconates and molybdate are eco-friendly, non-toxic chemicals. The corrosion inhibition of calcium gluconate and sodium molybdate on carbon steel in neutral aqueous media was evaluated by means of weight loss, electrochemical polarisation and impedance techniques. A synergistic effect was observed when these two eco-friendly

  18. Thermodynamic behaviour of sodium and calcium based sorbents in the emission control of waste incinerators.

    PubMed

    Verdone, Nicola; De Filippis, Paolo

    2004-02-01

    The dry treatment of flue gas produced by incineration processes is discussed thermodynamically. The study investigates the theoretical limits achieved by sodium and calcium based sorbents in the removal of the pollutant species HCl, NOx and SO2. Calculations were performed varying the temperature and the molar ratio between the amount of the injected alkaline sorbent and the content of the pollutant gaseous species in the flue gas. Results show that sodium cation based sorbents are more efficient than calcium based ones in the whole investigated temperature range (100-600 degrees C). The higher effectiveness of sodium based sorbents is particularly remarkable towards hydrogen chloride, whose concentration can always be reduced below the values set by the environmental regulations. Possible improvements in the treatment efficiency of combustion fumes obtainable with sodium based sorbents can be mainly summarised in a lower concentration of HCl in the treated gas and in a partial reduction of NOx concentration. PMID:14637355

  19. Dietary Sodium Effects on Bone Loss and Calcium Metabolism During Bed Rest

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Arnaud, Sara B.; Abrams, Steven A.; Paloski, W. H. (Technical Monitor)

    2000-01-01

    The acceleration of age-related bone loss is one of the most detrimental effects of space flight. The ability to understand and counteract this loss will be critical for crew health and safety during and after long-duration missions. Studies in healthy ambulatory individuals have linked high salt (sodium) diets, hypercalciuria, and increased renal stone risk. Dietary salt may modulate bone loss through changes in calcium metabolism and the calcium endocrine system. The research proposed here will determine the role of dietary salt in the loss of bone during simulated space flight. Calcium metabolism will be determined through calcium kinetics studies, endocrine and biochemical measurements; and estimates of the mass, distribution and mechanical properties of bone, in subjects fed low (100 mmol sodium/day) or high (250 mmol sodium/day) levels of dietary salt during 28 days of headdown tilt bedrest. This research addresses the role of dietary salt in the loss of bone and calcium in space flight, and integrates the changes in calcium metabolism with those occurring in other physiologic systems. These data will be critical for both countermeasure development, and in determination of nutritional requirements for extended-duration space flight. The potential countermeasures resulting from this research will reduce health risks due to acceleration of age-related osteoporosis and increased risk of renal stone formation..

  20. Enzymatic changes in liver in Calcium oxalate stone forming rats treated with sodium pentosan polysulphate

    Microsoft Academic Search

    K. Subha; P. Varalakshmi

    1992-01-01

    The effect of sodium pentosan polysulphate (SPP) in calcium oxalate stone forming rats was studied in relation to enzymatic\\u000a changes in liver. A significant increase in liver glycollate oxidase (GAO) activity was observed in stone forming rats fed\\u000a sodium glycollate. SPP treatment lowered the enzyme acitivity in both stone formers and 30 days drug treated control rats.\\u000a Moderate elevation in

  1. Variation in crystal structure, ionic conductivity, and magnetic properties with the water uptake of a new hydrated sodium beta'' ferrite

    Microsoft Academic Search

    S. Nicolopoulos; H. Vincent; M. Anne; J. C. Joubert

    1990-01-01

    The room temperature single-crystal X-ray data of Na1.5(H3O)0.5 Fe10ZnO17 + 0.3H2O (hydrated sodium beta'' alumina-like ferrite) were refined. The space group is R3m and the hexagonal cell parameters are a = 5.940, c = 35.731 Å. Water molecules are localized in the conduction region and the total amount of absorbed water depends on hydration conditions, leading to different possible chemical

  2. The relationship among intracellular sodium activity, calcium, and strophanthidin inotropy in canine cardiac Purkinje fibers

    PubMed Central

    1984-01-01

    The role of sodium and calcium ions in strophanthidin inotropy was studied by measuring simultaneously the electrical, mechanical, and intracellular sodium ion activities in electrically driven cardiac Purkinje fibers under conditions that change the intracellular sodium or calcium level (tetrodotoxin, strophanthidin, high calcium, and norepinephrine). Tetrodotoxin (TTX; 1-5 X 10(-6)M) shifted the action potential plateau to more negative values, shortened the action potential duration, and decreased the contractile tension and the intracellular sodium ion activity (aiNa). The changes in tension and in aiNa caused by TTX appear to be related since they had similar time courses. Strophanthidin (2-5 X 10(-7)M) increased tension and aiNa less in the presence of TTX, and, for any given value of aiNa, tension was less than in the absence of TTX. Increasing extracellular calcium (from 1.8 to 3.3-3.6 mM) or adding norepinephrine (0.5-1 X 10(-6)M) increased tension and decreased aiNa less in the presence than in the absence of TTX. When two of the above procedures were combined, the results were different. Thus, during the increase in aiNa and tension caused by strophanthidin in the presence of TTX, increasing calcium or adding norepinephrine increased tension markedly but did not increase aiNa further. In a TTX-high calcium or TTX-norepinephrine solution, adding strophanthidin increased both tension and aiNa, and the increase in tension was far greater than in the presence of TTX alone. The results indicate that: (a) the contractile force in Purkinje fibers is affected by a change in aiNa; (b) a decrease in aiNa by TTX markedly reduces the inotropic effect of strophanthidin, possibly as a consequence of depletion of intracellular calcium; (c) increasing calcium influx with norepinephrine or high calcium in the TTX-strophanthidin solution produces a potentiation of tension development, even if aiNa does not increase further; and (d) when the calcium influx is already increased by high calcium or norepinephrine, strophanthidin has its usual inotropic effect even in the presence of TTX. In conclusion, the positive inotropic effect of strophanthidin requires that an increase in aiNa be associated with suitable calcium availability. PMID:6325584

  3. Ion-exchange characteristics of sodium-calcium-silicate glass: Calculation from mode spectra

    NASA Astrophysics Data System (ADS)

    Zhurikhina, V. V.; Petrov, M. I.; Sokolov, K. S.; Shustova, O. V.

    2010-10-01

    The characteristics of silver-sodium ion exchange in standard commercial sodium-calcium-silicate glass are investigated using mode spectroscopy. The activation energy of the process, the silver-sodium interdiffusion coefficient, and the dependence of the maximal modulation of the refractive index on the silver nitrate concentration in the experimental salt bath are determined. The data set presented here makes it possible to specify the conditions for the formation of ion-exchange optical structures with preset parameters based on the glasses studied here.

  4. Calcium-Silicate-Hydrate in cementitious systems : chemomechanical correlations, extreme temperature behavior, and kinetics and morphology of in-situ formation

    E-print Network

    Jagannathan, Deepak

    2013-01-01

    Concrete, the second most used material on the planet, is a multi-scale heterogeneous material. A fundamental component known as Calcium-Silicate-Hydrate which forms from the reaction between cement and water is the binding ...

  5. ALZHEIMER'S AMYLOID-BETA PEPTIDE INHIBITS SODIUM/CALCIUM EXCHANGE MEASURED IN RAT AND

    E-print Network

    ALZHEIMER'S AMYLOID-BETA PEPTIDE INHIBITS SODIUM/CALCIUM EXCHANGE MEASURED IN RAT AND HUMAN BRAIN vesicles isolated from normal and Alzheimer's disease frontal cortex with less potency but the same mechanisms of A -induced neurotoxicity in cell culture has yet to be solved. Accumulation of free radicals

  6. Thermodynamic behaviour of sodium and calcium based sorbents in the emission control of waste incinerators

    Microsoft Academic Search

    Nicola Verdone; Paolo De Filippis

    2004-01-01

    The dry treatment of flue gas produced by incineration processes is discussed thermodynamically. The study investigates the theoretical limits achieved by sodium and calcium based sorbents in the removal of the pollutant species HCl, NOx and SO2. Calculations were performed varying the temperature and the molar ratio between the amount of the injected alkaline sorbent and the content of the

  7. Effects of Dietary Sodium Bicarbonate and Calcium Chloride on Physiological Responses of Lactating Dairy Cows in Hot Weather

    Microsoft Academic Search

    A. Escobosa; C. E. Coppock; L. D. Rowe Jr; W. L. Jenkins; C. E. Gates

    1984-01-01

    Twenty-four lactating cows were as- signed randomly to three treatments to evaluate responses to large differences of dietary sodium and chloride. Treatments were corn-cottonseed meal-corn silage based complete rations with either: 1) .23% sodium chloride (control), 2) control plus 2.28% calcium chloride, or 3) control plus 1.70% sodium bicarbonate.

  8. A clinical study of the effect of calcium sodium phosphosilicate on dentin hypersensitivity

    PubMed Central

    Surve, Sai M.; Thakur, Srinath L.

    2013-01-01

    Objective: Dentinal hypersensitivity is a commonly encountered problem with varied treatment options for its management. A large number of home use products have been tested and used for the management of dentinal hypersensitivity. This 8 week clinical trial investigates the temporal efficacy of commercially available calcium sodium phosphosilicate containing toothpaste in comparison to a potassium nitrate containing toothpaste. Methods: A total 20 subjects between the ages of 18 to 65 years were screened for a visual analogue score (VAS) for sensitivity of 5 or more by testing with a cold stimulus and randomly divided into test and positive control groups. Baseline sensitivity VAS scores to air evaporative stimulus were recorded for minimum two teeth. The subjects were prescribed respective dentifrices and revaluated for sensitivity scores at 2, 4 and 8 weeks. Results:The study demonstrated reduction in symptoms for all treatment groups from baseline to 2, 4 and 8 weeks. The calcium sodium phosphosilicate group showed a higher degree of effectiveness at reducing hypersensitivity to air evaporative stimulus at 2 weeks, than commercially available potassium nitrate. However, there was no significant difference in scores of subjects using the calcium sodium phosphosilicate toothpaste as compared to potassium nitrate at 4 weeks and 8 weeks. Conclusion: Calcium sodium phosphosilicate showed greater reduction in sensitivity compared to potassium nitrate at an earlier stage which is of high clinical value. However, based on the findings of the present study long term effects of calcium sodium phosphosilicate seem to be less promising than previously claimed. Key words:Dentinal desensitizing agents, dentinal hypersensitivity, toothpaste, pain measurement. PMID:24455046

  9. Glycine enhances microglial intracellular calcium signaling. A role for sodium-coupled neutral amino acid transporters.

    PubMed

    Van den Eynden, Jimmy; Notelaers, Kristof; Brône, Bert; Janssen, Daniel; Nelissen, Katherine; Sahebali, Sheen; Smolders, Inge; Hellings, Niels; Steels, Paul; Rigo, Jean-Michel

    2011-04-01

    The inhibitory neurotransmitter glycine is known to enhance microglial nitric oxide production. However, up to now, the mechanism is undocumented. Since calcium is an important second messenger in both immune and glial cells, we studied the effects of glycine on intracellular calcium signaling. We found that millimolar concentrations of glycine enhance microglial intracellular calcium transients induced by 100 ?M ATP or by 500 nM thapsigargin. This modulation was unaffected by the glycine receptor antagonist strychnine and could not be mimicked by glycine receptor agonists such as taurine or ?-alanine, indicating glycine receptor independency. The modulation of calcium responses could be mimicked by several structurally related amino acids (e.g., serine, alanine, or glutamine) and was inhibited in the presence of the neutral amino acid transporter substrate ?-aminoisobutyric acid (AIB). We correlated these findings to immunofluorescence glycine uptake experiments which showed a clear glycine uptake which was inhibited by AIB. Furthermore, all amino acids that were shown to modulate calcium responses also evoked AIB-sensitive inward currents, mainly carried by sodium, as demonstrated by patch clamp experiments. Based on these findings, we propose that sodium-coupled neutral amino acid transporters are responsible for the observed glycine modulation of intracellular calcium responses. PMID:21350800

  10. Calcium-aluminum-silicate-hydrate "cement" phases and rare Ca-zeolite association at Colle Fabbri, Central Italy

    NASA Astrophysics Data System (ADS)

    Stoppa, F.; Scordari, F.; Mesto, E.; Sharygin, V.; Bortolozzi, G.

    2010-06-01

    Very high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate-alkaline hydrothermal plume produced a zone of mineralization several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate (CSH), i.e., tobermorite-afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) — "cement" phases - i.e., thaumasite, strätlingite and an ettringite-like phase and several different species of zeolites: chabazite-Ca, willhendersonite, gismon-dine, three phases bearing Ca with the same or perhaps lower symmetry of phillipsite-Ca, levyne-Ca and the Ca-rich analogue of merlinoite. In addition, apophyllite-(KF) and/or apophyllite-(KOH), Ca-Ba-carbonates, portlandite and sulphates were present. A new polymorph from the pyrrhotite group, containing three layers of sphalerite-type structure in the unit cell, is reported for the first time. Such a complex association is unique. Most of these minerals are specifically related to hydration processes of: (1) pyrometamorphic metacarbonate/metapelitic rocks (natural analogues of cement clinkers); (2) mineralization between intrusive stocks and slates; and (3) high-calcium, alkaline igneous rocks such as melilitites and foidites as well as carbonatites. The Colle Fabbri outcrop offers an opportunity to study in situ complex crystalline overgrowth and specific crystal chemistry in mineral phases formed in igneous to hydrothermal conditions.

  11. Sodium and carbonate distribution in substituted calcium hydroxyapatite

    Microsoft Academic Search

    Hafed El Feki; Jean Michel Savariault; Abdelhamid Ben Salah; Mohamed Jemal

    2000-01-01

    Hydroxyapatites containing sodium and carbonate are prepared according to a double decomposition method. Two samples have been investigated by IR absorption spectroscopy and X-ray powder pattern fitting methods. Results confirm that both compounds pertain to the apatite family crystallising in a hexagonal system, space group P63\\/m. The cell parameters of the lower carbonate content apatite are a=9.3892(4) and c=6.9019(3) Å,

  12. Non-ideal solid solution aqueous solution modeling of synthetic calcium silicate hydrate

    SciTech Connect

    Walker, Colin S. [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol, BS8 1RJ (United Kingdom)]. E-mail: c.walker@nhm.ac.uk; Savage, David [Quintessa Limited, Dalton House, Newtown Road, Henley-on-Thames, RG9 1HG (United Kingdom); Tyrer, Mark [Department of Materials, Imperial College, South Kensington, London, SW7 2AZ (United Kingdom); Ragnarsdottir, K. Vala [Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol, BS8 1RJ (United Kingdom)

    2007-04-15

    New data relevant to calcium silicate hydrate (C-S-H) gels prepared at room temperature have been obtained over a time period of up to 112 weeks. X-ray diffraction (XRD) indicates equilibrium was attained after 64 weeks. Coupled with fourier transform infrared (FT-IR) spectroscopy, a phase change in C-S-H gel at Ca/Si {approx} 1.0 was identified and the occurrence of portlandite as a distinct phase for Ca/Si > 1.64. The incongruent dissolution of C-S-H gel was modeled as a non-ideal solid solution aqueous solution (SSAS) between the end-member components CaH{sub 2}SiO{sub 4} (CSH) and Ca(OH){sub 2} (CH) using equations defining the solidus and solutus curves on a Lippmann phase diagram. Despite being semi-empirical, the model provides a reasonable and consistent fit to the solubility data and can therefore be used to describe the incongruent dissolution of C-S-H gels with compositions Ca/Si {>=} 1.0.

  13. Dissolution-precipitation behaviour of ettringite, monosulfate, and calcium silicate hydrate

    SciTech Connect

    Baur, Isabel; Keller, Peter; Mavrocordatos, Denis; Wehrli, Bernhard; Johnson, C. Annette

    2004-02-01

    The stability of the cement minerals ettringite, monosulfate, and calcium silicate hydrate (C-S-H) was investigated to better understand the uptake of contaminants in waste-cement mixes. Suspensions were spiked with radioisotopes of components ({sup 45}Ca and {sup 35}SO{sub 4} for ettringite and monosulfate and {sup 45}Ca and {sup 32}Si for C-S-H) to observe their uptake behaviour within 0-70 days. A physical model was applied to determine dissolution-precipitation rates. An initial fast uptake was observed to occur in most systems, so the data obtained between 7 and 70 days were chosen for analysis. Dissolution-precipitation rates were in the range of 10{sup -11.5} to 10{sup -12.2} mol m{sup -2} s{sup -1} for all minerals. The whole solids would be dissolved and reprecipitated within 1-4 years. The measured dissolution-precipitation rates of pure cement minerals give the maximum rate for ion substitution processes with contaminants and are distinguishable from faster processes such as surface complexation and ion exchange processes.

  14. Stabilization of ZnCl2-containing wastes using calcium sulfoaluminate cement: cement hydration, strength development and volume stability.

    PubMed

    Berger, Stéphane; Cau Dit Coumes, Céline; Le Bescop, Patrick; Damidot, Denis

    2011-10-30

    The potential of calcium sulfoaluminate (CSA) cement was investigated to solidify and stabilize wastes containing large amounts of soluble zinc chloride (a strong inhibitor of Portland cement hydration). Hydration of pastes and mortars prepared with a 0.5 mol/L ZnCl(2) mixing solution was characterized over one year as a function of the gypsum content of the binder and the thermal history of the material. Blending the CSA clinker with 20% gypsum enabled its rapid hydration, with only very small delay compared with a reference prepared with pure water. It also improved the compressive strength of the hardened material and significantly reduced its expansion under wet curing. Moreover, the hydrates assemblage was less affected by a thermal treatment at early age simulating the temperature rise and fall occurring in a large-volume drum of cemented waste. Fully hydrated materials contained ettringite, amorphous aluminum hydroxide, strätlingite, together with AFm phases (Kuzel's salt associated with monosulfoaluminate or Friedel's salt depending on the gypsum content of the binder), and possibly C-(A)-S-H. Zinc was readily insolubilized and could not be detected in the pore solution extracted from cement pastes. PMID:21889260

  15. Calcium silicate hydrates investigated by solid-state high resolution {sup 1}H and {sup 29}Si nuclear magnetic resonance

    SciTech Connect

    Meducin, Fabienne [Laboratoire de Physique et Mecanique des Milieux Heterogenes, Ecole Superieure de Physique et Chimie Industrielles, 75231 Paris Cedex 05 (France)]. E-mail: meducin@cnrs-orleans.fr; Bresson, Bruno [Laboratoire de Physique Quantique, ESPCI (France); Lequeux, Nicolas [Laboratoire de Physico-Chimie des polymeres et des milieux disperses, ESPCI (France); Noirfontaine, Marie-Noelle de [Laboratoire CECM-CNRS, 15, rue Georges Urbain, 94407 Vitry sur Seine (France); Zanni, Helene [Laboratoire de Physique et Mecanique des Milieux Heterogenes, Ecole Superieure de Physique et Chimie Industrielles, 75231 Paris Cedex 05 (France)

    2007-05-15

    This work focuses on phases formed during cement hydration under high pressure and temperature: portlandite Ca(OH){sub 2} (CH); hillebrandite Ca{sub 2}(SiO{sub 3})(OH){sub 2} ({beta}-dicalcium silicate hydrate); calcium silicate hydrate (C-S-H); jaffeite Ca{sub 6}(Si{sub 2}O{sub 7})(OH){sub 6} (tricalcium silicate hydrate); {alpha}-C{sub 2}SH Ca{sub 2}(SiO{sub 3})(OH){sub 2} ({alpha}-dicalcium silicate hydrate); xonotlite Ca{sub 6}(Si{sub 6}O{sub 17})(OH){sub 2} and kilchoanite Ca{sub 6}(SiO{sub 4})(Si{sub 3}O{sub 10}). Portlandite and hillebrandite were synthesized and characterised by high resolution solid-state {sup 1}H and {sup 29}Si Nuclear Magnetic Resonance. In addition, information from the literature concerning the last five phases was gathered. In certain cases, a schematic 3D-structure could be determined. These data allow identification of the other phases present in a mixture. Their morphology was also observed by Scanning Electron Microscopy.

  16. Effects of Hypotonic Saline Loading in Hydrated Dog: Evidence for a Saline-induced Limit on Distal Tubular Sodium Transport*

    PubMed Central

    Stein, Richard M.; Abramson, Ruth G.; Kahn, Thomas; Levitt, Marvin F.

    1967-01-01

    We performed studies on dogs under hydrated conditions, utilizing the rate of free water formation (CH2O) as an index of the rate of distal tubular sodium transport. Since CH2O could be progressively increased with no evidence of a maximal rate during loading with hypotonic (2.5%) mannitol, it was concluded that there is no limit on distal tubular sodium transport during mannitol loading. In contrast, during hypotonic (0.45%) saline loading CH2O rose initially, but as urine flow (V) exceeded 25% of the filtered load CH2O attained maximal levels (up to 20% of the filtered load) and remained stable as V increased to 50% of the filtered load. It was concluded that saline loading progressively inhibits proximal sodium reabsorption. Initially, the distal tubule absorbes a large fraction of the proximal rejectate and sodium excretion rises slightly. Eventually, an alteration in distal sodium transport appears which culminates in a maximal rate or transport limit. This distal transport limit provoked by saline loading could not be characterized by a classical Tm as seen with glucose and does not seem to be consequent to high rates of flow through the distal tubule. Regardless of the precise nature of this limit, the major increment in sodium excretion develops during saline loading only after saline alters the capacity of the distal tubule to transport sodium. PMID:6027084

  17. NALCN Ion Channels Have Alternative Selectivity Filters Resembling Calcium Channels or Sodium Channels

    PubMed Central

    Senatore, Adriano; Monteil, Arnaud; van Minnen, Jan; Smit, August B.; Spafford, J. David

    2013-01-01

    NALCN is a member of the family of ion channels with four homologous, repeat domains that include voltage-gated calcium and sodium channels. NALCN is a highly conserved gene from simple, extant multicellular organisms without nervous systems such as sponges and placozoans and mostly remains a single gene compared to the calcium and sodium channels which diversified into twenty genes in humans. The single NALCN gene has alternatively-spliced exons at exons 15 or exon 31 that splices in novel selectivity filter residues that resemble calcium channels (EEEE) or sodium channels (EKEE or EEKE). NALCN channels with alternative calcium, (EEEE) and sodium, (EKEE or EEKE) -selective pores are conserved in simple bilaterally symmetrical animals like flatworms to non-chordate deuterostomes. The single NALCN gene is limited as a sodium channel with a lysine (K)-containing pore in vertebrates, but originally NALCN was a calcium-like channel, and evolved to operate as both a calcium channel and sodium channel for different roles in many invertebrates. Expression patterns of NALCN-EKEE in pond snail, Lymnaea stagnalis suggest roles for NALCN in secretion, with an abundant expression in brain, and an up-regulation in secretory organs of sexually-mature adults such as albumen gland and prostate. NALCN-EEEE is equally abundant as NALCN-EKEE in snails, but is greater expressed in heart and other muscle tissue, and 50% less expressed in the brain than NALCN-EKEE. Transfected snail NALCN-EEEE and NALCN-EKEE channel isoforms express in HEK-293T cells. We were not able to distinguish potential NALCN currents from background, non-selective leak conductances in HEK293T cells. Native leak currents without expressing NALCN genes in HEK-293T cells are NMDG+ impermeant and blockable with 10 µM Gd3+ ions and are indistinguishable from the hallmark currents ascribed to mammalian NALCN currents expressed in vitro by Lu et al. in Cell. 2007 Apr 20;129(2):371-83. PMID:23383067

  18. EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS

    SciTech Connect

    Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

    2001-12-01

    Powdered activated carbon (PAC) has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated disinfection by-products (DBPs). Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. The Energy & Environmental Research Center has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During previous studies, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon product. As much as a 130% increase in the humic acid sorption capacity of a PAC produced from a high-sodium-content lignite was observed. During this study, activated carbons were prepared from three coals representing high-sodium, low-sodium--low-calcium, and high-calcium compositions in two steps, an initial char formation followed by mild activation with steam to avoid excessive burnout. This set of carbons was characterized with respect to physical and chemical properties. The BET (Brunauer-Emmett-Teller) nitrogen adsorption isotherms gave relatively low surface areas (ranging from 245 to 370 m{sup 2}/g). The lowest-BET area was obtained for the high-sodium carbon, which can be attributed to enlargement of micropores as a result of sodium-catalyzed gasification reaction of the carbon structure. This hypothesis is consistent with the scanning electron microscopy microprobe analyses, which show that in both the coal and the activated carbon from this coal, the sodium is distributed over both the carbon structure and the mineral particles. Thus it is initially associated with carboxylate groups on the coal and then as sodium oxide or other active form in close proximity to the carbon and is, therefore, readily available for catalysis of gasification. Humate adsorption isotherms for the high-sodium carbon gave superior results as defined by very high intercepts in modified Freundlich plots. Thus the high-sodium carbon will be considerably more effective in reducing the humate concentration for a given carbon dosage. Analysis of adsorption isotherms indicated the results were consistent with the hypothesis that only the larger pores are effective for binding the large humate molecules, and that the larger pores developed during activation of the high-sodium char give the appropriate macropore structure for humate binding. Toluene adsorption isotherms indicated that the high-calcium carbon and the low-calcium, low-sodium carbon were superior to the high-sodium carbon for small molecules in aqueous solution, but not as effective as a Calgon F-400 commercial activated carbon. This is consistent with the low-BET surface areas observed for the lignite-derived carbons, and thus there are a lower number of sites for binding the smaller toluene molecule in these carbons.

  19. Lead and zinc retention during hydration of tri-calcium silicate: A study by sorption isotherms and ²⁹Si nuclear magnetic resonance spectroscopy

    Microsoft Academic Search

    Isabelle Moulin; J. Y. Bottero; W. E. E. Stone; J. Sanz; Francis Mosnier; Claude Haehnel

    1999-01-01

    In cement-based materials heavy metals contents are rarely larger than a few hundred parts per million. Sorption isotherms of Zn(II) and Pb(II) carried out on nonhydrated (CâS) and hydrated (C-S-H) calcium silicate show t hat lead and zinc have different affinities for calcium silicate in a concentration range lower than the saturation concentration values of PbO and calcium zinc hydroxide.

  20. Toward a microscopic understanding of the calcium-silicate-hydrates/water interface

    NASA Astrophysics Data System (ADS)

    Ebbert, Christoph; Grundmeier, Guido; Buitkamp, Nadine; Kröger, Alexander; Messerschmidt, Florian; Thissen, Peter

    2014-01-01

    Calcium-Silicate-Hydrates (C-S-H) are the main binding phases in most concrete which is the primarily used composite construction material in the world. However, a big lack is cleaving between the actual knowledge about C-S-H, compared to what could be reached using state-of-the-art technologies of modern research. In this article, the formation of a C-S-H phase on a native oxide covered silicon wafer is investigated by means of in-situ attenuated total reflection infrared (ATR-IR) and ex-situ surface-enhanced Raman spectroscopy (SERS). The total thickness of the C-S-H phase is determined by X-ray photoelectron spectroscopy (XPS) to be 3 nm. The formation appears to be reversible depending on the environment pH value and can be performed at room temperature. Based on density functional theory (DFT) calculations, it is shown that the C-S-H phase in the presence of water will change its chemical composition in order to reach the thermodynamic ground state of the system. This change is achieved by a metal-proton exchange reaction. The stoichiometry of these metal-proton exchange reactions is nearly independent of the environment pH value. Electrokinetic measurements yield isoelectric points of 2.0 and 2.6 for the native oxide covered silicon wafer (SiO2) and the C-S-H phase. This is consistent with a predominance of Si-O sites at the C-S-H/water interface.

  1. Amorphous calcium silicate hydrate/block copolymer hybrid nanoparticles: synthesis and application as drug carriers.

    PubMed

    Wu, Jin; Zhu, Ying-Jie; Chen, Feng; Zhao, Xin-Yu; Zhao, Jing; Qi, Chao

    2013-05-21

    Amorphous calcium silicate hydrate (CSH)/block copolymer monomethoxy(polyethyleneglycol)-block-poly(lactide-co-glycolide) (mPEG-PLGA) (CSHP) hybrid nanoparticles have been prepared in aqueous solution via a facile coprecipitation route at room temperature. The block copolymer mPEG-PLGA micelles in aqueous solution serve as the templates, and the CSH links to the micelles by hydrogen bonding between the silanol groups and the hydrophilic mPEG segments. The obtained core/shell hybrid nanoparticles can be transformed to solid hybrid nanoparticles by washing with water. The drug ibuprofen (IBU) loading capacity of the CSHP hybrid nanoparticles is ultrahigh (~1.9 g drug per g carrier), and the IBU loading efficiency can reach as high as ~100%. The drug release of loaded IBU in the CSHP hybrid nanoparticles has been investigated in simulated body fluid (SBF). The loaded IBU drug in CSHP hybrid nanoparticles can release in SBF for a long period of time (about 300 h), during which the CSHP nanocarrier is completely transformed to hydroxyapatite, exhibiting a good bioactivity. The IBU drug release profile can be interpreted by the Higuchi model. The loading capacity for the anticancer drug docetaxel (DTX) in the CSHP hybrid nanoparticles is about 82 mg g(-1). More importantly, the release of the loaded DTX in phosphate buffer saline (PBS) at pH 5.5 is obviously faster than that at pH 7.4, which is promising for the application in cancer therapy. Human gastric carcinoma (SGC-7901) cells can be effectively killed in the presence of the DTX-loaded CSHP hybrid nanoparticles at appropriate concentrations. Thus, the CSHP hybrid nanoparticles are promising nanocarriers in drug delivery. Furthermore, the hemoglobin (Hb) loading capacity of CSHP hybrid nanoparticles can achieve an utrahigh value of 995 mg g(-1), suggesting that the as-prepared CSHP hybrid nanoparticles are excellent protein adsorbents. PMID:23511873

  2. Kinetics of HCl reactions with calcium and sodium sorbents for IGCC fuel gas cleaning

    Microsoft Academic Search

    J. H. A. Kiel; A. Bos; H. Den Uil

    1996-01-01

    Experiments for HCl sorption by calcium and sodium sorbents have been carried out with simulated gases of compositions typical for “air-blown” and “oxygen-blown” IGCC fuel gases. The concentration of CO2 affects the behaviour of HCl sorption by Ca-sorbents but does not influence the performance of Na-sorbents in the temperature range 300–600°C. The sorbent particle size has a slight effect on

  3. Economic comparison of calcium fumarate and sodium fumarate production by Rhizopus arrhizus

    Microsoft Academic Search

    Irene C. Gangl; William A. Weigand; Frederick A. Keller

    1990-01-01

    The economics of using Na2CO3 rather than CaCO3 as the neutralizing agent in fumaric acid production byRhizopus arrhizus is investigated and compared with the benzene route. Because sodium fumarate, unlike calcium fumarate, is soluble, downstream\\u000a processing is simplified by requiring less equipment and no heat, and also allows the reuse of cells. In spite of a fumaric\\u000a acid productivity (g\\/L\\/h)

  4. Small-scale pilot evaluation of calcium- and sodium-based sorbents for dry SOâ removal

    Microsoft Academic Search

    C. Jorgensen; J. C. S. Chang; T. G. Brna; C. B. Sedman

    1987-01-01

    A 100 m³\\/h pilot facility incorporating a spray dryer, a sorbent injection system, a duct section, and a pulse jet baghouse or cyclone separator was used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SOâ in the concentration range of 1000-2500 ppm. The specific sorbents selected for testing were based on earlier reported sand-bed

  5. The effects of calcium on branchial sodium fluxes in the sea-water adapted eel, Anguilla anguilla, L

    PubMed Central

    Bornancin, M.; Cuthbert, A. W.; Maetz, J.

    1972-01-01

    1. The sodium influx through the gills of eels placed in calcium-free sea water for 15 hr was double that of controls. The effect was reversed in 1 hr by addition of calcium. 2. The total sodium outflux through the gills of fish placed in calcium-free sea water for 15 hr was double that of controls. The effect was only partially reversed in 15 hr by addition of calcium. 3. The passive outflux component of the total outflux was increased fourfold when calcium was removed and was restored to normal in 15 hr by addition of calcium. The active (exchange) outflux component of the total outflux was halved by calcium removal and increased above normal following calcium addition. 4. The inability of calcium to restore the total outflux to normal within 15 hr in calcium-depleted fish, together with the raised plasma sodium concentration at this time, suggests that the raised outflux is caused by homoeostatic mechanisms, rather than permeability changes in the gill epithelium. PMID:5033473

  6. Hydration and strength development of binder based on high-calcium oil shale fly ash

    Microsoft Academic Search

    C Freidin

    1998-01-01

    The properties of high-calcium oil shale fly ash and low-calcium coal fly ash, which are produced in Israeli power stations, were investigated. High-calcium oil shale fly ash was found to contain a great amount of CaOfree and SO3 in the form of lime and anhydrite. Mixtures of high-calcium oil shale fly ash and low-calcium coal fly ash, termed fly ash

  7. Ternary phase behaviour and vesicle formation of a sodium N-lauroylsarcosinate hydrate/1-decanol/water system

    NASA Astrophysics Data System (ADS)

    Akter, Nasima; Radiman, Shahidan; Mohamed, Faizal; Rahman, Irman Abdul; Reza, Mohammad Imam Hasan

    2011-08-01

    The phase behaviour of a system composed of amino acid-based surfactant (sodium N-lauroylsarcosinate hydrate), 1-decanol and deionised water was investigated for vesicle formation. Changing the molar ratio of the amphiphiles, two important aggregate structures were observed in the aqueous corner of the phase diagram. Two different sizes of microemulsions were found at two amphiphile-water boundaries. A stable single vesicle lobe was found for 1?2 molar ratios in 92 wt% water with vesicles approximately 100 nm in size and with high zeta potential value. Structural variation arises due to the reduction of electrostatic repulsions among the ionic headgroups of the surfactants and the hydration forces due to adsorbed water onto monolayer's. The balance of these two forces determines the aggregate structures. Analysis was followed by the molecular geometrical structure. These findings may have implications for the development of drug delivery systems for cancer treatments, as well as cosmetic and food formulations.

  8. Pore solution in alkali-activated slag cement pastes. Relation to the composition and structure of calcium silicate hydrate

    SciTech Connect

    Puertas, F.; Fernandez-Jimenez, A.; Blanco-Varela, M.T

    2004-01-01

    In this work, the relationship between the composition of pore solution in alkali-activated slag cement (AAS) pastes activated with different alkaline activator, and the composition and structure of the main reaction products, has been studied. Pore solution was extracted from hardened AAS pastes. The analysis of the liquids was performed through different techniques: Na, Mg and Al by atomic absorption (AA), Ca ions by ionic chromatography (IC) and Si by colorimetry; pH was also determined. The solid phases were analysed by XRD, FTIR, solid-state {sup 29}Si and {sup 27}Al NMR and BSE/EDX. The most significant changes in the ionic composition of the pore solution of the AAS pastes activated with waterglass take place between 3 and 24 h of reaction. These changes are due to the decrease of the Na content and mainly to the Si content. Results of {sup 29}Si MAS NMR and FTIR confirm that the activation process takes place with more intensity after 3 h (although at this age, Q{sup 2} units already exist). The pore solution of the AAS pastes activated with NaOH shows a different evolution to this of pastes activated with waterglass. The decrease of Na and Si contents progresses with time. The nature of the alkaline activator influences the structure and composition of the calcium silicate hydrate formed as a consequence of the alkaline activation of the slag. The characteristic of calcium silicate hydrate in AAS pastes activated with waterglass is characterised by a low structural order with a low Ca/Si ratio. Besides, in this paste, Q{sup 3} units are detected. The calcium silicate hydrate formed in the pastes activated with NaOH has a higher structural order (higher crystallinity) and contains more Al in its structure and a higher Ca/Si ratio than those obtained with waterglass.

  9. Corrosion resistance of inconel 690 to sodium carbonate, calcium carbonate, and sodium meta silicate at 900 and 1100{degrees}C

    SciTech Connect

    Imrich, K.J.

    1997-01-29

    Corrosive attack of Inconel 690 coupons was not observed following 3 day exposure tests to calcium carbonate, sodium carbonate, and sodium meta silicate at 900 {degrees}C. However, melt line attack was evident on coupons exposed to sodium meta silicate and sodium carbonate tested for 3 days at 1100 {degrees}C. In addition, intergranular attack (IGA), approximately 0.67 mils/day, was observed on the Inconel 690 coupon exposed to calcium carbonate at 1100 {degrees}C. Calcium carbonate did not completely remove the glass coating at 950 {degrees}C. In fact, it was comparable to the results obtained by exposing a glass coated coupon at 950 {degrees}C in air. Therefore, calcium carbonate is not recommended for cleaning the DWPF melter pour spout. Both sodium carbonate and sodium meta silicate appear to remove most of the glass. However, these cleaning agents will remain on the metal surface following exposure at 950 {degrees}C resulting in very rough surface and a potential for corrosive attack when heated to 1100 {degrees}C.

  10. Imaging of drug loading distributions in individual microspheres of calcium silicate hydrate - an X-ray spectromicroscopy study.

    PubMed

    Guo, Xiaoxuan; Wang, Zhiqiang; Wu, Jin; Wang, Jian; Zhu, Ying-Jie; Sham, Tsun-Kong

    2015-04-01

    Imaging is one of the most direct and ideal ways to track drug loading distributions in drug carriers on the molecular level, which will facilitate the optimization of drug carriers and drug loading capacities. Herein, we report the mapping of an individual mesoporous calcium silicate hydrate (CSH) microsphere before and after the loading of ibuprofen (IBU) and the interactions between drug carriers and drug molecules simultaneously by scanning transmission X-ray microscopy (STXM). Nanoscaled X-ray absorption near edge structure (XANES) spectroscopy clearly indicates that IBU is bonded to calcium and silicate sites via carboxylic acid groups. More importantly, STXM has been successfully used to determine the absolute thickness of IBU, revealing its distribution in the CSH microsphere. PMID:25804516

  11. Physiological characterisation of a pH and calcium-dependent sodium uptake mechanism in the freshwater crustacean, Daphnia magna

    Microsoft Academic Search

    Chris N. Glover; Chris M. Wood

    2005-01-01

    Daphnia are highly sensitive to sodium metabolism disruption caused by aquatic acidification and ionoregulatory toxicants, due to their finely balanced ion homeostasis. Nine different water chemistries of varying pH (4, 6 and 8) and calcium concentration (0, 0.5 and 1·mmol·l -1 ) were used to delineate the mechanism of sodium influx in Daphnia magna. Lowering water pH severely inhibited sodium

  12. The characterization of hardened alkali-activated blast-furnace slag pastes and the nature of the calcium silicate hydrate (CSH) phase

    Microsoft Academic Search

    I. G. Richardson; A. R. Brough; G. W. Groves; C. M. Dobson

    1994-01-01

    Calcium silicate hydrate (C-S-H) gel is the principal binding phase in hardened OPC pastes and concretes, and also when the OPC has been partially replaced by pozzolanic by-products such as ground granulated blast-furnace slag (GGBFS) and pulverized fuel ash. The C-S-H gels present in commercial blast-furnace slag and synthetic-slag glass pastes produced by hydrating with 5M KOH solution have been

  13. Influence of Calcium Hydroxide Dissolution on the Transport Properties of Hydrated Cement Systems

    E-print Network

    Bentz, Dale P.

    with data of calcium leaching experimentsperformed in deionizedwater. INTRODUCTION Calcium hydroxide (CH to approximately 100 microns in diameterl,2. The leaching of calcium may be a matter of concern for the durability of the surface layers of concrete, and detrimentally affect the resistance of the material to deicer salt scaling

  14. Surfactant effects on hydrate formation in an unstirred gas\\/liquid system: An experimental study using HFC32 and sodium dodecyl sulfate

    Microsoft Academic Search

    Kazuyoshi Watanabe; Shuntaro Imai; Yasuhiko H. Mori

    2005-01-01

    This paper deals with the effects of a surfactant additive on the formation of a clathrate hydrate in a quiescent guest-gas\\/liquid–water system. The paper first presents our strong suspicion against the existing hypothesis that the surfactant-micelle formation in the liquid–water phase promotes the hydrate formation. It is pointed out that the Krafft point for sodium dodecyl sulfate (SDS), a popular

  15. Inhibition of ?-Cell Sodium-Calcium Exchange Enhances Glucose-Dependent Elevations in Cytoplasmic Calcium and Insulin Secretion

    PubMed Central

    Hamming, Kevin S.C.; Soliman, Daniel; Webster, Nicola J.; Searle, Gavin J.; Matemisz, Laura C.; Liknes, David A.; Dai, Xiao-Qing; Pulinilkunnil, Thomas; Riedel, Michael J.; Dyck, Jason R.B.; MacDonald, Patrick E.; Light, Peter E.

    2010-01-01

    OBJECTIVE The sodium-calcium exchanger isoform 1 (NCX1) regulates cytoplasmic calcium (Ca2+c) required for insulin secretion in ?-cells. NCX1 is alternatively spliced, resulting in the expression of splice variants in different tissues such as NCX1.3 and -1.7 in ?-cells. As pharmacological inhibitors of NCX1 splice variants are in development, the pharmacological profile of ?-cell NCX1.3 and -1.7 and the cellular effects of NCX1 inhibition were investigated. RESEARCH DESIGN AND METHODS The patch-clamp technique was used to examine the pharmacological profile of the NCX1 inhibitor KB-R7943 on recombinant NCX1.3 and -1.7 activity. Ca2+ imaging and membrane capacitance were used to assess the effects of KB-R7943 on Ca2+c and insulin secretion in mouse and human ?-cells and islets. RESULTS NCX1.3 and -1.7 calcium extrusion (forward-mode) activity was ?16-fold more sensitive to KB-R7943 inhibition compared with cardiac NCX1.1 (IC50s = 2.9 and 2.4 vs. 43.0 ?mol/l, respectively). In single mouse/human ?-cells, 1 ?mol/l KB-R7943 increased insulin granule exocytosis but was without effect on ?-cell glucagon granule exocytosis. KB-R7943 also augmented sulfonylurea and glucose-stimulated Ca2+c levels and insulin secretion in mouse and human islets, although KB-R7943 was without effect under nonstimulated conditions. CONCLUSIONS Islet NCX1 splice variants display a markedly greater sensitivity to pharmacological inhibition than the cardiac NCX1.1 splice variant. NCX1 inhibition resulted in glucose-dependent increases in Ca2+c and insulin secretion in mouse and human islets. Thus, we identify ?-cell NCX1 splice variants as targets for the development of novel glucose-sensitive insulinotropic drugs for type 2 diabetes. PMID:20413506

  16. Calcium role in base-line and ADH-stimulated sodium transport in frog skin.

    PubMed

    Casavola, V; Svelto, M

    1985-01-01

    Treatment of ventral frog skin with serosal A23187 calcium ionophore caused an initially transient increase in transepithelial sodium transport. After 60 min of treatment with A23187, a steady-state transport value was reached which was significantly lower than the initial one. Furthermore, it was found that ionophore treatment greatly inhibited the natriferic response to ADH and to 8br-cAMP. A further analysis on the possible ionophore action mechanism was carried out through pretreatment of the skin with indomethacin, very powerful prostaglandin synthesis inhibitor. In the experimental conditions reported, A23187 seems no longer capable of inducing a transient increase in sodium transport, although it does inhibit the natriferic response to ADH. PMID:2858310

  17. Human water, sodium, and calcium regulation during space flight and exercise

    NASA Astrophysics Data System (ADS)

    Doty, S. E.; Seagrave, R. C.

    When one is exposed to microgravity, fluid which is normally pooled in the lower extremities is redistributed headward and weight bearing bones begin to demineralize due to reduced mechanical stresses. The kidney, which is the primary regulator of body fluid volume and composition, responds to the fluid shift and bone demineralization by increasing the urinary output of water, sodium, and calcium. This research involves developing a mathematical description of how water and electrolytes are internally redistributed and exchanged with the environment during space flight. This model consequently involves kidney function and the associated endocrine system. The model agrees well with actual data, including that a low sodium diet can prevent bone demineralization. Therefore, assumptions made to develop the model are most likely valid. Additionally, various levels of activity are also considered in the model since exercise may help to eliminate some of the undesired effects of space flight such as muscle atrophy and bone demineralization.

  18. Human water, sodium, and calcium regulation during space flight and exercise

    NASA Astrophysics Data System (ADS)

    Doty, S. E.; Seagrave, R. C.

    2000-05-01

    When one is exposed to microgravity, fluid which is normally pooled in the lower extremities is redistributed headward and weight bearing bones begin to demineralize due to reduced mechanical stresses. The kidney, which is the primary regulator of body fluid volume and composition, responds to the fluid shift and bone demineralization by increasing the urinary output of water, sodium, and calcium. This research involves developing a mathematical description of how water and electrolytes are internally redistributed and exchanged with the environment during space flight. This model consequently involves kidney function and the associated endocrine system. The model agrees well with actual data, including that a low sodium diet can prevent bone demineralization. Therefore, assumptions made to develop the model are most likely valid. Additionally, various levels of activity are also considered in the model since exercise may help to eliminate some of the undesired effects of space flight such as muscle atrophy and bone demineralization.

  19. The regulation of corneal hydration by a salt pump requiring the presence of sodium and bicarbonate ions

    PubMed Central

    Hodson, Stuart

    1974-01-01

    1. The use of polyacrylamide gel salt bridges enables trans-membrane potentials to be measured to an accuracy of 20 ?V over long periods. 2. The technique is applied to measure electrical potentials across corneal endothelia of rabbits. 3. In de-epithelialized corneas which translocate water, a spontaneous potential of 550 ?V is found across the endothelium (tissue resistance 20 ? cm2). 4. This electrical potential (and water translocation) is reduced to zero when sodium is absent from the Ringer, and by about 80% when bicarbonate ions are absent. Removal of chloride has no such effect. 5. Under a variety of conditions, the potential correlates with the observed translocation of fluid across corneal endothelium. The translocated fluid is shown to be isotonic with sodium in the Ringer and therefore the potential correlates with `active' sodium transport. 6. The potential and water translocation are abolished in the presence of ouabain at concentrations greater than 10-5 M. 7. The potential (lens-side negative) is of the wrong polarity to explain the net sodium transport (into the lens-side) by a sodium ion `pump'. 8. The current does not equal the net sodium flux under short circuit conditions. They differ in magnitude and polarity. 9. A model is proposed where the endothelium `pumps' salt out of the corneal stroma into the aqueous humour. 10. Flux equations are derived for a condition where the membrane (corneal endothelium) separates an ion exchanger (corneal stroma) from free solution (aqueous humour), where the usual relationship for free-free solutions ?? = cs??s does not apply. 11. The model is of use only when the stroma is well stirred. It may be used in whole corneas retaining their epithelium but it may not be used in de-epithelialized corneas. 12. The model predicts that the presence of an `active' salt flux out across the endothelium would create passive water and salt fluxes. The passive water flux would also travel out of the stroma across the endothelium; the passive salt flux would travel, in the opposite direction, into the stroma across the endothelium. 13. The kinetics of the passive water efflux, as a swollen cornea reverts to physiological hydration (the temperature reversal phenomenon) are predicted extremely well if the `active' salt flux is chosen at 3·3 × 10-7 m-mole. cm-2 sec-1. 14. The value of the active salt flux which cannot be measured directly is extrapolated to be somewhat greater than 2·8 × 10-7 m-moles. cm-2 sec-1; in good agreement with that required by the model to explain the temperature reversal phenomenon. 15. The model is further used to calculate the salt concentration difference across the endothelium (which drives salt passively into the stroma) at various stromal hydrations. 16. When an appropriate salt concentration is applied across the endothelium of de-epithelialized cornea, it generates a potential of the same polarity and similar magnitude to that found across the endothelium of equilibrated whole cornea. The endothelium acts like a cation exchange membrane. 17. Additionally the calculated salt concentration difference across the endothelium correlates well with the measured transendothelial potentials in whole cornea as the corneal hydration varies. 18. It is concluded that the model of an endothelial neutral salt `pump' regulating corneal hydration is self consistent. The spontaneous potential found across the endothelium could be caused by the consequential passive flux of salt in the opposite direction. PMID:16992435

  20. Mechanical and hydration properties of ground granulated blastfurnace slag pastes activated with MgO-CaO mixtures

    E-print Network

    Gu, Mai; Jin, Fei; Al-Tabbaa, Abir; Shi, Bin; Liu, Jin

    2014-08-07

    activated by sodium silicate. Constr Build Mater 2008;22:1981–9. [9] Yang K-H, Cho A-R, Song J-K, Nam S-H. Hydration products and strength development of calcium hydroxide-based alkali-activated slag mortars. Constr Build Mater 2012;29:410–9. [10] Van... . Sodium silicate-based , alkali-activated slag mortars Part I . Strength , hydration and microstructure 2002;32:865–79. [42] Richardson J, Biernacki J. Stoichiometry of slag hydration with calcium hydroxide. J Am Ceram Soc 2002;85:947–53. [43...

  1. Behaviour of calcium sulfoaluminate cement in presence of high concentrations of chromium salts

    Microsoft Academic Search

    C. A. Luz; J. Pera; M. Cheriaf; J. C. Rocha

    2007-01-01

    This paper deals with the behaviour of calcium sulfoaluminate cement hydrated in presence of high concentration of soluble chromium salts (65 g\\/kg): chromium nitrate and sodium chromate. Chromium nitrate was chosen to verify the good retention of Cr3+ by calcium sulfoaluminate cement. Sodium chromate was employed to assess the ability of calcium sulfoaluminate to immobilize Cr6+.Leaching tests were carried out on

  2. Ethanol inhibition of active sup 86 Rb(+)-transport: Evidence for enhancement by sodium or calcium influx

    SciTech Connect

    Swann, A.C. (Univ. of Texas Medical School, Houston (USA))

    1990-09-01

    We investigated interactions between ethanol and active cation transport mediated by Na,K-ATPase in rat brain synaptoneurosomes. Conditions that increased internal sodium also increased sensitivity of transport to ethanol, whereas low-sodium medium had the opposite effect. Ethanol also blocked the stimulation of ouabain-sensitive transport, glucose uptake and hyperpolarization associated with sodium influx. Low calcium decreased, while the calcium ionophore A23187 increased, sensitivity to ethanol. Inhibition of mitochondrial respiration or incubation under anaerobic conditions increased sensitivity of transport to inhibition by ethanol, but did not prevent the effect of A23187. Consistent with increased sensitivity to ethanol by cell calcium, ethanol potentiated the inhibition of transport by A23187. Although transport under basal conditions does not appear very sensitive to ethanol, these data suggest that sensitivity to ethanol may be increased under conditions associated with increased neural activity, and that ethanol may reduce the transport response to electrical activity.

  3. The mechanism of vapor phase hydration of calcium oxide: implications for CO2 capture.

    PubMed

    Kud?acz, Krzysztof; Rodriguez-Navarro, Carlos

    2014-10-21

    Lime-based sorbents are used for fuel- and flue-gas capture, thereby representing an economic and effective way to reduce CO2 emissions. Their use involves cyclic carbonation/calcination which results in a significant conversion reduction with increasing number of cycles. To reactivate spent CaO, vapor phase hydration is typically performed. However, little is known about the ultimate mechanism of such a hydration process. Here, we show that the vapor phase hydration of CaO formed after calcination of calcite (CaCO3) single crystals is a pseudomorphic, topotactic process, which progresses via an intermediate disordered phase prior to the final formation of oriented Ca(OH)2 nanocrystals. The strong structural control during this solid-state phase transition implies that the microstructural features of the CaO parent phase predetermine the final structural and physicochemical (reactivity and attrition) features of the product hydroxide. The higher molar volume of the product can create an impervious shell around unreacted CaO, thereby limiting the efficiency of the reactivation process. However, in the case of compact, sintered CaO structures, volume expansion cannot be accommodated in the reduced pore volume, and stress generation leads to pervasive cracking. This favors complete hydration but also detrimental attrition. Implications of these results in carbon capture and storage (CCS) are discussed. PMID:25233236

  4. Expression of the Sodium/Calcium/Potassium Exchanger, NCKX4, in Ameloblasts

    PubMed Central

    Hu, Ping; Lacruz, Rodrigo S.; Smith, Charles E.; Smith, Susan M.; Kurtz, Ira; Paine, Michael L.

    2012-01-01

    Transcellular calcium transport is an essential activity in mineralized tissue formation, including dental hard tissues. In many organ systems, this activity is regulated by membrane-bound sodium/calcium (Na+/Ca2+) exchangers, which include the NCX and NCKX [sodium/calcium-potassium (Na+/Ca2+-K+ ) exchanger] proteins. During enamel maturation, when crystals expand in thickness, Ca2+ requirements vastly increase but exactly how Ca2+ traffics through ameloblasts remains uncertain. Previous studies have shown that several NCX proteins are expressed in ameloblasts, although no significant shifts in expression were observed during maturation which pointed to the possible identification of other Ca2+ membrane transporters. NCKX proteins are encoded by members of the solute carrier gene family, Slc24a, which include 6 different proteins (NCKX1–6). NCKX are bidirectional electrogenic transporters regulating Ca2+ transport in and out of cells dependent on the transmembrane ion gradient. In this study we show that all NCKX mRNAs are expressed in dental tissues. Real-time PCR indicates that of all the members of the NCKX group, NCKX4 is the most highly expressed gene transcript during the late stages of amelogenesis. In situ hybridization and immunolocalization analyses clearly establish that in the enamel organ, NCKX4 is expressed primarily by ameloblasts during the maturation stage. Further, during the mid-late maturation stages of amelogenesis, the expression of NCKX4 in ameloblasts is most prominent at the apical poles and at the lateral membranes proximal to the apical ends. These data suggest that NCKX4 might be an important regulator of Ca2+ transport during amelogenesis. PMID:22677781

  5. Hot alkali carbonation of sodium metaphosphate modified fly ash/calcium aluminate blend hydrothermal cements

    SciTech Connect

    Sugama, T. [Brookhaven National Lab., Upton, NY (United States). Energy Efficiency and Conservation Div.] [Brookhaven National Lab., Upton, NY (United States). Energy Efficiency and Conservation Div.

    1996-11-01

    Sodium metaphosphate-modified fly ash/calcium aluminate blend (SFCB) cements were prepared by autoclaving for 1 day at 300 C and their resistance was evaluated in a highly concentrated Na{sub 2}CO{sub 3} solution at 300 C. The hydroxyapatite and analcime phases formed in the autoclaved SFCB cements played an essential role in conferring resistance to the degradation of cements caused by alkali carbonation. Although the carbonating reaction of the analcime phase led to the formation of cancrinite, this analcime cancrinite transformation did not show any influence on the changes in the mechanical and physical properties of the cements. Additionally, there was no formation of the water-soluble calcium bicarbonate in the cements exposed for 28 days. Contrarily, the conventional class G cement systems were very vulnerable to a hot alkali carbonation. The major reason for the damage caused by carbonation of the cements was the fact that the xonotlite phase formed in the 300{degree} autoclaved cements was converted into two carbonation products, calcite and pectolite. Furthermore, the reaction between calcite and carbonic acid derived from Na{sub 2}CO{sub 3} led to the formation of water-soluble calcium bicarbonate, thereby causing the alteration of dense structures into porous ones and the loss of strength of cements.

  6. ORM-10103: a significant advance in sodium-calcium exchanger pharmacology?

    PubMed Central

    Terracciano, C M; Hancox, J C

    2013-01-01

    The sodium-calcium exchanger (NCX) is an electrogenic transporter that is widely expressed in different tissues. In the heart, the NCX plays important roles in calcium ion homeostasis, excitation-contraction coupling and the electrophysiological properties of cardiac myocytes. Precise determination of the roles of the NCX has somewhat been hampered by a lack of selective small molecule inhibitors. In this issue of the BJP, Jost and colleagues present data on a new NCX inhibitor, ORM-10103, which has submicromolar EC50 values against cardiac forward and reverse exchange activity. The compound exhibits improved selectivity over existing small molecule NCX inhibitors and, in particular, appears to be without effect on L-type calcium channels at high concentrations. ORM-10103 could therefore have significant value for studies of the (patho)physiological roles of the NCX in the heart. Further pharmacological studies are required to investigate the actions of ORM-10103 on cardiac cells and tissues and to determine its effects on non-cardiac NCX isoforms. Linked Article This article is a commentary on Jost et al., pp. 768–778 of this issue. To view this paper visit http://dx.doi.org/10.1111/bph.12228 PMID:23848255

  7. The effect of calcium on gill potentials and on sodium and chloride fluxes in the goldfish, Carassius auratus

    Microsoft Academic Search

    F. B. Eddy

    1975-01-01

    Measurements of electric potential and of sodium and chloride effluxes were carried out on a freshwater fish, the goldfishCarassius auratus. The potential was affected by a number of inorganic ion species but that with the most significant influence on transepithelial potential was calcium. The potential was about 10 mV negative in the absence of calcium and about 10 mV positive

  8. Role of Sodium and Calcium Channel Block in Unmasking the Brugada Syndrome

    PubMed Central

    Fish, Jeffrey M.; Antzelevitch, Charles

    2006-01-01

    Objective: The Brugada syndrome (BS) is characterized by an ST segment elevation in the right precordial ECG leads and a high risk of sudden death. The ECG sign of BS is often concealed, but can be unmasked with potent sodium channel blockers. Using canine right ventricular (RV) wedge preparations, we previously developed an experimental model of BS using flecainide to depress the action potential (AP) dome in RV epicardium. We hypothesized that a combination of INa and ICa blockade may be more effective in causing loss of the epicardial AP dome and precipitating the syndrome. The present study was designed to test this hypothesis using terfenadine, an antihistamine known to block both INa and ICa (as well as IKr). Methods: Intracellular APs and a transmural ECG were simultaneously recorded from canine RV wedge preparations. Results: Terfenadine (5-10 ?M) caused a heterogeneous loss of the epicardial AP dome, resulting in ST segment elevation, phase 2 reentry (12/16), and spontaneous polymorphic VT/VF (6/16). Flecainide (?7.5 ?M), ajmaline (?20 ?M) and procainamide (?300 ?M) failed to generate polymorphic VT in any preparation except when combined with a calcium channel blocker (verapamil, ?20 ?M). Terfenadine-induced ST segment elevation was normalized and arrhythmias suppressed following Ito block with 4-aminopyridine (0.5 - 2 mM). Conclusion: Our data suggest that combined sodium and calcium channel block may be more effective than sodium channel block alone in unmasking the Brugada syndrome and that pharmacologic agents that inhibit Ito may be useful in preventing lethal arrhythmias in patients with the syndrome. PMID:15851155

  9. Cation Hydration Constants by Proton NMR: A Physical Chemistry Experiment.

    ERIC Educational Resources Information Center

    Smith, Robert L.; And Others

    1988-01-01

    Studies the polarization effect on water by cations and anions. Describes an experiment to illustrate the polarization effect of sodium, lithium, calcium, and strontium ions on the water molecule in the hydration spheres of the ions. Analysis is performed by proton NMR. (MVL)

  10. Interaction between alpha-calcium sulfate hemihydrate and superplasticizer from the point of adsorption characteristics, hydration and hardening process

    SciTech Connect

    Guan Baohong; Ye Qingqing; Zhang Jiali; Lou Wenbin [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China); Wu Zhongbiao, E-mail: zbwu@zju.edu.c [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China)

    2010-02-15

    Superplasticizers (SPs), namely sulfonated melamine formaldehyde (SMF) and polycarboxylate (PC), were independently admixed with alpha-calcium sulfate hemihydrate based plaster to improve the material's performance. SMF and PC gave, respectively, 38% and 25% increases in the 2 h bending strength at the optimum dosages of 0.5 wt.% and 0.3 wt.%, which are determined essentially by the maximum water-reducing efficiency. The peak shift of binding energy of Ca2p{sub 3/2} detected by X-ray photoelectron spectroscopy (XPS) suggests that SPs are chemically adsorbed on gypsum surface. A careful examination of the strength development of set plaster allowed the hydration and hardening process to be divided roughly into five stages. SMF accelerates early hydration, while PC decelerates it. Both SPs allowed similar maximum water reductions, giving a more compact structure and a decrease in total pore volume and average pore diameter, and thus leading to higher strengths in the hardened plasters with SPs.

  11. Alendronate sodium hydrate (oral jelly) for the treatment of osteoporosis: review of a novel, easy to swallow formulation

    PubMed Central

    Imai, Kazuhiro

    2013-01-01

    Osteoporosis is a skeletal disorder characterized by loss of bone mass, decreased bone strength, and an increased risk of bone fracture. The disease progresses with age, especially in postmenopausal women. Japan is one of the most rapidly aging societies worldwide. Japanese individuals over 65 years of age constituted 23.0% of the population in 2010 and 25.1% to 25.2% as of 2013. The estimated number of people with osteoporosis in Japan is currently 13 million. Bisphosphonates increase bone mineral density by inhibiting osteoclast-mediated bone resorption, thereby reducing the risk of fractures. Alendronate sodium hydrate (alendronate) is a bisphosphonate that potently inhibits bone resorption and is used to treat osteoporosis. Sufficient water is required to take an alendronate oral tablet; insufficient water could result in digestive system diseases, such as esophageal ulceration. Elderly patients with swallowing difficulty may choke on the tablet. Taking a tablet with oral jelly is a method to prevent digestive system disease and reduce the choking hazard. Once-weekly alendronate oral jelly was approved in 2012 by the Ministry of Health, Labour, and Welfare of Japan as the world’s first drug for osteoporosis in a jelly formulation. It consists of a jelly portion and an air portion. The jelly formulation is smoothly discharged by pushing the air portion. Therefore, elderly patients with physical disabilities are able to easily take all of the jelly formulation from the package. In this review, this new formulation of alendronate sodium hydrate (oral jelly) is introduced and discussed in terms of osteoporosis treatment. This new formulation provides an alternative so that patients may select a method of dosing tailored to their preferences. Management of osteoporosis involves assessing fracture risk and preventing fractures. Higher adherence to the treatment of patients with osteoporosis and prevention of osteoporotic fractures are issues to be resolved. PMID:23766643

  12. Application of ultrasonic testing to describe the hydration of calcium aluminate cement at the early age

    Microsoft Academic Search

    T Chotard; N Gimet-Breart; A Smith; D Fargeot; J. P Bonnet; C Gault

    2001-01-01

    Nondestructive and in situ characterisation techniques, such as ultrasonic measurements, permit to follow cement hydration at the early age from a few minutes to a few hours after mixing. The technique reported in this paper is based on measurements in reflection modes. Results concerning an aluminous cement, Secar71, are presented (water-to-cement weight ratio (W\\/C): 0.3 and 0.4; temperature of measurement:

  13. Inhibitors of arachidonate-regulated calcium channel signaling suppress triggered activity induced by the late sodium current.

    PubMed

    Wolkowicz, Paul; Umeda, Patrick K; Sharifov, Oleg F; White, C Roger; Huang, Jian; Mahtani, Harry; Urthaler, Ferdinand

    2014-02-01

    Disturbances in myocyte calcium homeostasis are hypothesized to be one cause for cardiac arrhythmia. The full development of this hypothesis requires (i) the identification of all sources of arrhythmogenic calcium and (ii) an understanding of the mechanism(s) through which calcium initiates arrhythmia. To these ends we superfused rat left atria with the late sodium current activator type II Anemonia sulcata toxin (ATXII). This toxin prolonged atrial action potentials, induced early afterdepolarization, and provoked triggered activity. The calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 (N-[2-[[[3-(4-chlorophenyl)-2-propenyl]methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulphon-amide) suppressed ATXII triggered activity but its inactive congener KN-92 (2-[N-(4-methoxy benzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine) did not. Neither drug affected normal atrial contractility. Calcium entry via L-type channels or calcium leakage from sarcoplasmic reticulum stores are not critical for this type of ectopy as neither verapamil ((RS)-2-(3,4-dimethoxyphenyl)-5-{[2-(3,4-dimethoxyphenyl)ethyl]-(methyl)amino}-2-prop-2-ylpentanenitrile) nor ryanodine affected ATXII triggered activity. By contrast, inhibitors of the voltage independent arachidonate-regulated calcium (ARC) channel and the store-operated calcium channel specifically suppressed ATXII triggered activity without normalizing action potentials or affecting atrial contractility. Inhibitors of cytosolic calcium-dependent phospholipase A2 also suppressed triggered activity suggesting that this lipase, which generates free arachidonate, plays a key role in ATXII ectopy. Thus, increased left atrial late sodium current appears to activate atrial Orai-linked ARC and store operated calcium channels, and these voltage-independent channels may be unexpected sources for the arrhythmogenic calcium that underlies triggered activity. PMID:24362110

  14. Rapid Determination of Milk Salts and Ions. I. Determination of Sodium, Potassium, Magnesium, and Calcium by Flame Spectrophotometry

    Microsoft Academic Search

    V. R. Wenner

    1958-01-01

    SUMMARY A rapid determination of milk cations is presented. A trained technician can make four to six complete analyses a day for sodium, potassium, calcium, and magnesium. The cation exchange resin Dowex 50 is used to eliminate, quantitatively, the total amount of cations from a milk serum prepared according to the procedure of Jenness (2) and Murthy and Whitney (4).

  15. Combination of sodium chlorite and calcium propionate reduces enzymatic browning and microbial population of fresh-cut ‘Granny Smith’ apples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tissue browning and microbial growth are the main concerns associated with fresh-cut apples. In this study, effects of sodium chlorite (SC) and calcium propionate (CP), individually and combined, on quality and microbial population of apple slices were investigated. ‘Granny Smith’ apple slices, dipp...

  16. Modified Calcium Alginate Beads with Sodium Dodecyl Sulfate and Clay as Adsorbent for Removal of Methylene Blue

    Microsoft Academic Search

    Paresh Parekh; Arpan Parmar; Suresh Chavda; Pratap Bahadur

    2011-01-01

    In present study, we have investigated the effect of an anionic surfactant sodium dodecyl sulfate (SDS) and clay on calcium alginate beads was studied to remove methylene blue (MB) and to to improve the adsorption capacity. The effects of various experimental parameters, such as shaking rate, initial dye concentration, temperature and pH on the adsorption rate have been studied. Equilibrium

  17. SMALL-SCALE PILOT EVALUATION OF CALCIUM- AND SODIUM-BASED SORBENTS FOR DRY SO2 REMOVAL

    EPA Science Inventory

    The paper discusses a 100 cu m/h pilot facility (consisting of a spray dryer, a sorbent injection system, a duct section, and a pulse-jet baghouse or cyclone separator) used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SO2 in ...

  18. Dietary sodium, potassium and calcium requirements of the house cricket, Acheta domesticus (L.).

    PubMed

    McFarlane, J E

    1991-01-01

    1. The optimal level of sodium in an artificial diet for the house cricket was found to be 1126 ppm, of potassium 6487 ppm and of calcium 1366 ppm. 2. The revised salt mixture for the house cricket is 68.02 g NaCl, 120.00 g KCl, 310.00 g KH2PO4, 37.65 g CaHPO4, 53.34 g CaCO3, 90.50 g MgSO4.7H2O, 14.70 g FePO4.4H2O, 0.23 g MnSO4.H2O, 0.55 g ZnCO3 and 0.72 g CnSO4 in a total of 695.71 g salts. PMID:1682100

  19. Sodium selenite penta­hydrate, Na2SeO3·5H2O

    PubMed Central

    Mereiter, Kurt

    2013-01-01

    In the crystal structure of Na2SeO3·5H2O [disodium selen­ate(IV) penta­hydrate], two Se, two selenite O atoms and one water O atom are located on a mirror plane, and one water O atom is located on a twofold rotation axis. The coordination of one Na+ cation is distorted trigonal bipyramidal, formed by three equatorial H2O ligands and two axial selenite O atoms. The other Na+ cation has an octa­hedral coordination by six water mol­ecules. The two independent SeO3 groups form almost undistorted trigonal pyramids, with Se—O bond lengths in the range 1.6856?(7)–1.7202?(10)?Å and O—Se—O angles in the range 101.98?(3)–103.11?(5)°, and both are ?2-O:O-bonded to a pair of Na+ cations. Hydrogen bonds involving all water molecules and selenite O atoms consolidate the crystal packing. Although anhydrous Na2SeO3 and Na2TeO3 are isotypic, the title compound is surprisingly not isotypic with Na2TeO3·5H2O. In the tellurite hydrate, all Na+ cations have an octa­hedral coordination and the TeO3 groups are bonded to Na+ only via one of their three O atoms. PMID:24454013

  20. Variation in crystal structure, ionic conductivity, and magnetic properties with the water uptake of a new hydrated sodium. beta. double prime ferrite

    Microsoft Academic Search

    S. Nicolopoulos; H. Vincent; M. Anne; J. C. Joubert

    1990-01-01

    The room temperature single-crystal x-ray data of Na{sub 1.5}(HâO){sub 0.5}FeââZnOââ + 0.3HâO (hydrated sodium β{double prime} alumina-like ferrite) were refined. The space group is R{anti 3}m and the hexagonal cell parameters are a = 5.940, c = 35.731 â«. Water molecules are localized in the conduction region and the total amount of absorbed water depends on hydration conditions, leading to

  1. Differential Hippocampal Protection when Blocking Intracellular Sodium and Calcium Entry during Traumatic Brain Injury in Rats

    PubMed Central

    Zhao, Xueren; Gorin, Fredric A.; Berman, Robert F.

    2008-01-01

    Abstract This study investigated the contributions of the reverse mode of the sodium-calcium exchanger (NCX) and the type 1 sodium-proton antiporter (NHE-1) to acute astrocyte and neuronal pathology in the hippocampus following fluid percussion traumatic brain injury (TBI) in the rat. KB-R7943, EIPA, or amiloride, which respectively inhibit NCX, NHE-1, or NCX, NHE-1, and ASIC1a (acid-sensing ion channel type 1a), was infused intraventricularly over a 60-min period immediately prior to TBI. Astrocytes were immunostained for glial fibrillary acidic protein (GFAP), and degenerating neurons were identified by Fluoro-Jade staining at 24?h after injury. Stereological analysis of the CA2/3 sub-regions of the hippocampus demonstrated that higher doses of KB-R7943 (2 and 20 nmoles) significantly reduced astrocyte GFAP immunoreactivity compared to vehicle-treated animals. EIPA (2–200 nmoles) did not alter astrocyte GFAP immunoreactivity. Amiloride (100 nmoles) significantly attenuated the TBI-induced acute reduction in astrocyte GFAP immunoreactivity. Of the three compounds examined, only amiloride (100 nmoles) reduced hippocampal neuronal degeneration assessed with Fluoro-Jade. The results provide additional evidence of acute astrocyte pathology in the hippocampus following TBI, while suggesting that activation of NHE-1 and the reverse mode of NCX contribute to both astrocyte and neuronal pathology following experimental TBI. PMID:18847376

  2. EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS

    SciTech Connect

    Edwin S. Olson; Kurt E. Eylands; Daniel J. Stepan

    2001-12-01

    New federal drinking water regulations have been promulgated to restrict the levels of disinfection by-products (DBPs) in finished public water supplies. DBPs are suspected carcinogens and are formed when organic material is partially oxidized by disinfectants commonly used in the water treatment industry. Additional federal mandates are expected in the near future that will also affect public water suppliers with respect to DBPs. These new federal drinking water regulations may require public water suppliers to adjust treatment practices or incorporate additional treatment operations into their existing treatment trains. Many options have been identified, including membrane processes, granular activated carbon, powered activated carbon (PAC), enhanced coagulation and/or softening, and alternative disinfectants (e.g., chlorine dioxide, ozone, and chloramines). Of the processes being considered, PAC appears to offer an attractive benefit-to-cost advantage for many water treatment plants, particularly small systems (those serving fewer than 10,000 customers). PAC has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated DBPs. Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. Activated carbons can be produced from a variety of raw materials, including wood, peat, coconut husks, and numerous types of coal. The Energy & Environmental Research Center (EERC) has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During that study, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon product. As much as a 130% increase in the humic acid sorption capacity of a PAC produced from a high-sodium-content lignite was observed. We hypothesize that the sodium and calcium content of the coal plays a significant role in the development of pore structures and pore-size distribution, ultimately producing activated carbon products that have greater sorption capacity for specific contaminants, depending on molecular size.

  3. X-ray diffraction: a powerful tool to probe and understand the structure of nanocrystalline calcium silicate hydrates

    PubMed Central

    Grangeon, Sylvain; Claret, Francis; Linard, Yannick; Chiaberge, Christophe

    2013-01-01

    X-ray diffraction (XRD) patterns were calculated and compared to literature data with the aim of investigating the crystal structure of nanocrystalline calcium silicate hydrates (C-S-H), the main binding phase in hydrated Portland cement pastes. Published XRD patterns from C-S-H of Ca/Si ratios ranging from ??0.6 to ??1.7 are fully compatible with nanocrystalline and turbostratic tobermorite. Even at a ratio close or slightly higher than that of jennite (Ca/Si = 1.5) this latter mineral, which is required in some models to describe the structure of C-S-H, is not detected in the experimental XRD patterns. The 001 basal reflection from C-S-H, positioned at ??13.5?Å when the C-S-H structural Ca/Si ratio is low (< 0.9), shifts towards smaller d values and sharpens with increasing Ca/Si ratio, to reach ??11.2?Å when the Ca/Si ratio is higher than 1.5. Calculations indicate that the sharpening of the 001 reflection may be related to a crystallite size along c* (i.e. a mean number of stacked layers) increasing with the C-S-H Ca/Si ratio. Such an increase would contribute to the observed shift of the 001 reflection, but fails to quantitatively explain it. It is proposed that the observed shift could result from interstratification of at least two tobermorite-like layers, one having a high and the other a low Ca/Si ratio with a basal spacing of 11.3 and 14?Å, respectively. PMID:24056355

  4. Effect of temperature on the microstructure of calcium silicate hydrate (C-S-H)

    SciTech Connect

    Gallucci, E., E-mail: gallucci.emmanuel@ch.sika.com; Zhang, X.; Scrivener, K.L.

    2013-11-15

    Temperature affects the properties of concrete through its effect on the hydration of cement and its associated microstructural development. This paper focuses on the modifications to C-S-H induced by isothermal curing between 5 and 60 °C. The results show that as the temperature increases (within the range studied) the C/S ratio of C-S-H changes only slightly, with a higher degree of polymerisation of silicate chains, but there is a significant decrease in its bound water content and an increase of apparent density of 25%. This increase seems to come from a different packing of C-S-H at the nanoscale. As a consequence of these changes, the microstructure of the cement paste is much coarser and porous, which explains the lower final strengths obtained by curing at elevated temperatures. -- Highlights: •C-S-H structure studied at the atomic level •Multiple analytical techniques used •Studies conducted at temperatures above and below normal temperatures.

  5. Calcium

    MedlinePLUS

    ... following: Milk, yogurt, and cheese are the main food sources of calcium for the majority of people in ... on Calcium Minerals, MedlinePlus® For more information on food sources of calcium: U.S. Department of Agriculture's (USDA) National ...

  6. Final Report On the Safety Assessment of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, and Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and Tea-Lactates, Methyl, Ethyl, Isopropyl, and Butyl Lactates, and Lauryl, Myristyl, and Cetyl Lactates

    Microsoft Academic Search

    F. A. Andersen

    1998-01-01

    This report provides a review of the safety of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and TEA-Lactates, and Lauryl, Myristyl, and Cetyl Lactates. These ingredients belong to a group known as alpha-hydroxy acids (AHAs). Products containing these ingredients may be for consumer use, salon use, or

  7. Altered sodium permeability, calcium binding and Na?K-ATPase activity in the red blood cell membrane in essential hypertension

    Microsoft Academic Search

    Yuvenaly V. Postnov; Sergey N. Orlov; Anatoly Shevchenko; Alexander M. Adler

    1977-01-01

    Summary  Red blood cells (RBC) of patients with essential hypertension differ from those of normotensive individuals by their higher\\u000a passive permeability for sodium ions (the rate constant of steady-state Na\\/Na exchange in RBC is 1.520.12 vs 0.700.12 \\u000a 10?5 mole\\/min l of cells).\\u000a \\u000a Calcium depletion of the RBC by EDTA results in the removal of more calcium ions from the outer part

  8. Calcium reabsorption in the distal tubule: regulation by sodium, pH, and flow.

    PubMed

    Bonny, Olivier; Edwards, Aurélie

    2013-03-01

    We developed a mathematical model of Ca(2+) transport along the late distal convoluted tubule (DCT2) and the connecting tubule (CNT) to investigate the mechanisms that regulate Ca(2+) reabsorption in the DCT2-CNT. The model accounts for apical Ca(2+) influx across transient receptor potential vanilloid 5 (TRPV5) channels and basolateral Ca(2+) efflux via plasma membrane Ca(2+)-ATPase pumps and type 1 Na(+)/Ca(2+) exchangers (NCX1). Model simulations reproduce experimentally observed variations in Ca(2+) uptake as a function of extracellular pH, Na(+), and Mg(2+) concentration. Our results indicate that amiloride enhances Ca(2+) reabsorption in the DCT2-CNT predominantly by increasing the driving force across NCX1, thereby stimulating Ca(2+) efflux. They also suggest that because aldosterone upregulates both apical and basolateral Na(+) transport pathways, it has a lesser impact on Ca(2+) reabsorption than amiloride. Conversely, the model predicts that full NCX1 inhibition and parathyroidectomy each augment the Ca(2+) load delivered to the collecting duct severalfold. In addition, our results suggest that regulation of TRPV5 activity by luminal pH has a small impact, per se, on transepithelial Ca(2+) fluxes; the reduction in Ca(2+) reabsorption induced by metabolic acidosis likely stems from decreases in TRPV5 expression. In contrast, elevations in luminal Ca(2+) are predicted to significantly decrease TRPV5 activity via the Ca(2+)-sensing receptor. Nevertheless, following the administration of furosemide, the calcium-sensing receptor-mediated increase in Ca(2+) reabsorption in the DCT2-CNT is calculated to be insufficient to prevent hypercalciuria. Altogether, our model predicts complex interactions between calcium and sodium reabsorption in the DCT2-CNT. PMID:23152295

  9. Physicochemical characterizations and desulfurization properties in coal combustion of three calcium and sodium industrial wastes

    SciTech Connect

    Jun Cheng; Junhu Zhou; Jianzhong Liu; Xinyu Cao; Kefa Cen [Zhejiang University, Hangzhou (China). State Key Laboratory of Clean Energy Utilization

    2009-05-15

    To recycle industrial wastes and reduce SO{sub 2} pollutant emission in coal combustion, the mineralogical compositions, porosity structures, surface morphologies, and desulfurization properties of three calcium and sodium industrial wastes were investigated via X-ray diffraction (XRD), porosimeter, scanning electron microscopy (SEM), and a fixed-bed reactor. (1) White lime mud (WLM) mainly composed of CaCO{sub 3} with Na{sub 2}O and K{sub 2}O impurities has smaller CaCO{sub 3} particles and a higher surface area than limestone. But calcined WLM has larger CaO particles and a lower surface area than limestone calcined at 1200{sup o}C for 300 s. (2) Calcium carbide residue (CCR) mainly composed of Ca(OH)2, has the highest surface area and smaller Ca(OH){sub 2} particles than the CaCO{sub 3} particles in WLM. Its surface area monotonously and dramatically decreases at 1200{sup o}C for 300 s, but the sintered CaO particles are still smaller than those in the limestone. (3) When brine sludge (BS), mainly composed of NaCl and CaCO{sub 3}, is heated at 1200{sup o}C for 300 s, the NaCl/CaO eutectic solvent facilitates the aggregation of some complex composites to form many larger particles. (4) WLM gives the highest desulfurization efficiency of 80.4% at 1000{sup o}C and 65.0% at 1100{sup o}C in coal combustion. Combined CCR and limestone give a synergistic desulfurization efficiency of 45.8% at 1200{sup o}C. BS with a molar ratio of Na/Ca at 1:15 effectively promotes the synergistic desulfurization efficiency of combined CCR and limestone to a peak of 54.9% at 1200{sup o}C. 23 refs., 10 figs., 3 tabs.

  10. Belite cements: modifications of calcium silicate hydrate (C-S-H) gel by alkaline hydrothermal activation

    SciTech Connect

    Guerrero, A.; Goni, S.; Dolado, J.S. [CSIC, Eduardo Torroja Inst. Construct. Sci., Madrid (Spain)

    2009-03-15

    The C-S-H gel of two types of fly ash belite cements (FABC) are studied at a nanoscale (1 to 100 nm (39.4 to 3940 nin.)) by means of the specific surface area and pore-size distribution, which were measured by the sorption isotherms of nitrogen gas and the BET method. The two belite cements were fabricated by the hydro-thermal-calcination route of Class C fly ash in NaOH 1M solution (FABC-2-N) and demineralized water (FABC-2-W). Two differentiated zones in the pore-size distribution of the C-S-H gel at similar to 12 and similar to 3 nm (similar to 473 and similar to 118 nin.) with different influences in the mechanical strength were produced. The proportion of both zones depends on the age of hydration and type of belite cement. At early ages, the C-S-H gel of FABC-2-N develops both zones in a greater proportion than those of FABC-2-W. At later ages, the behavior is opposite: the C-S-H gel of FABC-2-W develops high proportion of pores of 3 nin (118 nm.) of diameter. Important quantitative correlations were found among these nanostructure characteristics of the C-S-H gel and macrostructural engineering property.

  11. Preparation, crystal structures and rapid hydration of P2- and P3-type sodium chromium antimony oxides

    SciTech Connect

    Pospelov, A.A. [Southern Federal University, 7 ul. Zorge, Rostov-na-Donu 344090 (Russian Federation); Nalbandyan, V.B., E-mail: vbn@sfedu.r [Southern Federal University, 7 ul. Zorge, Rostov-na-Donu 344090 (Russian Federation)

    2011-05-15

    Two new Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2} compounds have been prepared by solid-state reactions in argon. Their structures have been determined by the X-ray Rietveld method. Both new phases together with NaCrO{sub 2}-based solid solution comprise brucite-like layers of edge-shared (Cr,Sb)O{sub 6} octahedra but differ by packing mode of the layers and coordination of the interlayer Na{sup +} ions. A P3 phase exists at x{approx}0.5-0.58. It is rhombohedral (R3-bar m), a=2.966, c=16.937 A at x{approx}0.58, with 29% Na{sup +} occupancy of trigonal prisms. A P2 phase exists at x{approx}0.6-0.7. It is hexagonal (P6{sub 3}/mmc), a=2.960, c=11.190 A at x{approx}0.7, with 37% and 33% Na{sup +} occupancy of two non-equivalent trigonal prisms. Both P2 and P3 phases rapidly absorb moisture in air; packing mode is preserved, the a parameter changes slightly but c increases by 24-25%. Very high sodium ion conductivity is predicted for both P2 and P3 anhydrous phases. -- Graphical Abstract: Polyhedral presentation of layered structures of Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2}. (Cr,Sb)O{sub 6} octahedra are green. Part of the sodium prisms are open to show short distances between sodium sites which cannot be occupied simultaneously. Display Omitted highlights: > Two new layered Na{sub x}[Cr{sub (1+x)/2}Sb{sub (1-x)/2}]O{sub 2} phases, P2 and P3, have been prepared in argon. > Interlayer O-O distances are larger than in Na{sub x}(M,Ti)O{sub 2} analogs (M=Cr,Ni,Li). > As a result, both rapidly hydrate in air with c-axis expansion of 24-25%. > Bottleneck radii are also larger, and this predicts very high Na{sup +}-ion conductivity.

  12. Equilibrium studies of sodium-ammonium potassium-ammonium, and calcium-ammonium exchanges on clinoptilolite zeolite

    SciTech Connect

    Jama, M.A.; Yuecel, H. (Middle East Technical Univ., Ankara (Turkey))

    1989-12-01

    Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv/dm{sup 3} and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full replacement of the cation by the ammonium ion is observed, which conflicts with some earlier work on clinoptilolite. Despite the observed partial exchange levels, clinoptilolite shows a very high preference for ammonium ion over sodium and calcium but not over potassium. Thermodynamic values for the exchanges were calculated and compared with data in the literature. Both the selectivity and thermodynamic affinity sequence, in agreement with previous work reported in the literature, are K{sup +} > NH{sub 4}{sup +} > Na{sup +} > Ca{sup 2+}.

  13. Calcium-Mediated Regulation of Proton-Coupled Sodium Transport - Final Report

    SciTech Connect

    Schumaker, Karen S [Professor] [Professor

    2013-10-24

    The long-term goal of our experiments was to understand mechanisms that regulate energy coupling by ion currents in plants. Activities of living organisms require chemical, mechanical, osmotic or electrical work, the energy for which is supplied by metabolism. Adenosine triphosphate (ATP) has long been recognized as the universal energy currency, with metabolism supporting the synthesis of ATP and the hydrolysis of ATP being used for the subsequent work. However, ATP is not the only energy currency in living organisms. A second and very different energy currency links metabolism to work by the movement of ions passing from one side of a membrane to the other. These ion currents play a major role in energy capture and they support a range of physiological processes from the active transport of nutrients to the spatial control of growth and development. In Arabidopsis thaliana (Arabidopsis), the activity of a plasma membrane Na+/H+ exchanger, SALT OVERLY SENSITIVE1 (SOS1), is essential for regulation of sodium ion homeostasis during plant growth in saline conditions. Mutations in SOS1 result in severely reduced seedling growth in the presence of salt compared to the growth of wild type. SOS1 is a secondary active transporter coupling movement of sodium ions out of the cell using energy stored in the transplasma membrane proton gradient, thereby preventing the build-up of toxic levels of sodium in the cytosol. SOS1 is regulated by complexes containing the SOS2 and CALCINEURIN B-LIKE10 (CBL10) or SOS3 proteins. CBL10 and SOS3 (also identified as CBL4) encode EF-hand calcium sensors that interact physically with and activate SOS2, a serine/threonine protein kinase. The CBL10/SOS2 or SOS3/SOS2 complexes then activate SOS1 Na+/H+ exchange activity. We completed our studies to understand how SOS1 activity is regulated. Specifically, we asked: (1) how does CBL10 regulate SOS1 activity? (2) What role do two putative CBL10-interacting proteins play in SOS1 regulation? (3) Are there differences in the regulation and/or activity of SOS1 in plants differing in their adaptation to salinity?

  14. Dual inhibition of sodium-mediated proton and calcium efflux triggers non-apoptotic cell death in malignant gliomas

    PubMed Central

    Harley, William; Floyd, Candace; Dunn, Tamara; Zhang, Xiao-Dong; Chen, Tsung-Yu; Hegde, Manu; Palandoken, Hasan; Nantz, Michael H.; Leon, Leonardo; Carraway, K L; Lyeth, Bruce; Gorin, Fredric A.

    2010-01-01

    Malignant glioma cells maintain an elevated intracellular pH (pHi) within hypoxic-ischemic tumor microenvironments through persistent activation of sodium-proton transport (McLean et al., 2000). Amiloride has been reported to selectively kill human malignant glioma cell lines but not primary astrocytes (Hegde et al., 2004). While amiloride reduces pHi of malignant gliomas by inhibiting isoform 1 of sodium-proton exchange (NHE1), direct acidification was shown to be cytostatic rather than cytotoxic. At cytotoxic concentrations, amiloride has multiple drug targets including inhibition of NHE1 and sodium calcium exchange. Amiloride's glioma cytotoxicity can be explained, at least in part, by dual inhibition of NHE1 and of Na+-dependent calcium efflux by isoform 1.1 of the sodium calcium exchanger (NCX1.1) , which increases [Ca2+]i and initiates glioma cell demise. As a result of persistent NHE1 activity, cytosolic free levels of sodium ([Na+]i) in U87 and C6 glioma cells are elevated 3-fold, as compared with normal astrocytes. Basal cytosolic free calcium levels ([Ca2+]i) also are increased 5-fold. 2?, 4?-dichlorobenzamil (DCB) inhibits the sodium-dependent calcium transporter (NCX1.1) much more potently than NHE1. DCB was employed in a concentration-dependent fashion in glioma cells to selectively inhibit the forward mode of NCX1.1 at ?1uM, while dually inhibiting both NHE1 and NCX1.1 at ?20uM. DCB (1uM) was not cytotoxic to glioma cells, while DCB (20?M) further increased basal elevated levels of [Ca2+]i in glioma cells that was followed by cell demise. Cariporide and SEA0400 are more specific inhibitors of NHE1 and NCX1.1 than amiloride or DCB, respectively. Individually, Cariporide and SEA0400 are not cytotoxic, but in combination induced glioma cell death. Like amiloride, the combination of Cariporide and SEA0400 produced glioma cell death in the absence of demonstrable caspase-activation. PMID:20869350

  15. Equilibrium Studies of Sodium-Ammonium, Potassium-Ammonium, and Calcium-Ammonium Exchanges on Clinoptilolite Zeolite

    Microsoft Academic Search

    M. A. Jama; H. Yuecel

    1989-01-01

    Forward and reverse ion-exchange isotherms for the binary sodium-ammonium, potassium-ammonium, and calcium-ammonium systems on clinoptilolite have been measured in aqueous solutions at a total concentration of 0.1 equiv\\/dm and at 298 K. Prior to exchange experiments it was attempted to prepare homoionic forms of the zeolite by exhaustive treatments with appropriate salt solutions of cations. With no binary exchanges, full

  16. Effect of SEA0400, a novel inhibitor of sodium-calcium exchanger, on myocardial ionic currents

    PubMed Central

    Tanaka, Hikaru; Nishimaru, Kazuhide; Aikawa, Tokiko; Hirayama, Wataru; Tanaka, Yoshio; Shigenobu, Koki

    2002-01-01

    The effects of 2-[4-[(2,5-difluorophenyl) methoxy]phenoxy]-5-ethoxyaniline (SEA0400), a newly synthesized Na+-Ca2+ exchanger (NCX) inhibitor, on the NCX current and other membrane currents were examined in isolated guinea-pig ventricular myocytes and compared with those of 2-[2-[4-(4-nitrobenzyloxy) phenyl]ethyl]isothiourea (KB-R7943). SEA0400 concentration-dependently inhibited the NCX current with a 10 fold higher potency than that of KB-R7943; 1??M SEA0400 and 10??M KB-R7943 inhibited the NCX current by more than 80%. KB-R7943, at 10??M, inhibited the sodium current, L-type calcium current, delayed rectifier potassium current and inwardly rectifying potassium current by more than 50%, but SEA0400 (1??M) had no significant effect on these currents. These results indicate that SEA0400 is a potent and highly selective inhibitor of NCX, and would be a powerful tool for further studies on the role of NCX in the heart and the therapeutic potential of its inhibition. PMID:11877314

  17. Structural Insight into the Ion-Exchange Mechanism of the Sodium/Calcium Exchanger

    SciTech Connect

    Liao, Jun; Li, Hua; Zeng, Weizhong; Sauer, David B.; Belmares, Ricardo; Jiang, Youxing (UTSMC)

    2012-06-19

    Sodium/calcium (Na{sup +}/Ca{sup 2+}) exchangers (NCX) are membrane transporters that play an essential role in maintaining the homeostasis of cytosolic Ca{sup 2+} for cell signaling. We demonstrated the Na{sup +}/Ca{sup 2+}-exchange function of an NCX from Methanococcus jannaschii (NCX{_}Mj) and report its 1.9 angstrom crystal structure in an outward-facing conformation. Containing 10 transmembrane helices, the two halves of NCX{_}Mj share a similar structure with opposite orientation. Four ion-binding sites cluster at the center of the protein: one specific for Ca{sup 2+} and three that likely bind Na{sup +}. Two passageways allow for Na{sup +} and Ca{sup 2+} access to the central ion-binding sites from the extracellular side. Based on the symmetry of NCX{_}Mj and its ability to catalyze bidirectional ion-exchange reactions, we propose a structure model for the inward-facing NCX{_}Mj.

  18. Transuranium removal from Hanford high level waste simulants using sodium permanganate and calcium

    NASA Astrophysics Data System (ADS)

    Wilmarth, W. R.; Rosencrance, S. W.; Nash, C. A.; Fonduer, F. F.; DiPrete, D. P.; DiPrete, C. C.

    2000-07-01

    Plutonium and americium are present in the Hanford high level liquid waste complexant concentrate (CC) due to the presence of complexing agents including di-(2-ethylhexyl) phosphoric acid (D2EHPA), tributylphosphate (TBP), hydroxyethylene diamine triacetic acid (HEDTA), ethylene diamine tetraacetic acid (EDTA), citric acid, glycolic acid, and sodium gluconate. The transuranic concentrations approach 600 nCi/g and require processing prior to encapsulation into low activity glass. BNFL's (British Nuclear Fuels Limited's) original process was a ferric co-precipitation method based on earlier investigations by Herting and Orth, et al. Furthermore, flocculation and precipitation are widely used for clarification in municipal water treatment. Co-precipitation of Np, Am, and Pu with ferric hydroxide is also used within an analytical method for the sum of those analytes. Tests to evaluate BNFL's original precipitation process indicated the measured decontamination factors (DFs) and filter fluxes were too low. Therefore, an evaluation of alternative precipitation agents to replace ferric ion was undertaken. Agents tested included various transition metals, lanthanide elements, uranium species, calcium, strontium, and permanganate.

  19. Methylmercury decreases cellular excitability by a direct blockade of sodium and calcium channels in bovine chromaffin cells: an integrative study.

    PubMed

    Fuentes-Antrás, J; Osorio-Martínez, E; Ramírez-Torres, M; Colmena, I; Fernández-Morales, J C; Hernández-Guijo, J M

    2013-12-01

    Methylmercury, a potent environmental pollutant responsible for fatal food poisoning, blocked calcium channels of bovine chromaffin cells in a time- and concentration-dependent manner with an IC50 of 0.93 ?M. This blockade was not reversed upon wash-out and was greater at more depolarising holding potentials (i.e. 21 % at -110 mV and 60 % at -50 mV, after 3 min perfusion with methylmercury). In ?-toxins-sensitive calcium channels, methylmercury caused a higher blockade of I Ba than in ?-toxins-resistant ones, in which a lower blockade was detected. The sodium current was also blocked by acute application of methylmercury in a time- and concentration-dependent manner with an IC50 of 1.05 ?M. The blockade was not reversed upon wash-out of the drug. The drug inhibited sodium current at all test potentials and shows a shift of the I-V curve to the left of about 10 mV. Intracellular dialysis with methylmercury caused no blockade of calcium or sodium channels. Voltage-dependent potassium current was not affected by methylmercury. Calcium- and voltage-dependent potassium current was also drastically depressed. This blockade was related to the prevention of Ca(2+) influx through voltage-dependent calcium channels coupled to BK channels. Under current-clamp conditions, the blockade of ionic current present during the generation and termination of action potentials led to a drastic alteration of cellular excitability. The application of methylmercury greatly reduced the shape and the number of electrically evoked action potentials. Taken together, these results point out that the neurotoxic action evoked by methylmercury may be associated to alteration of cellular excitability by blocking ionic currents responsible for the generation and termination of action potentials. PMID:23821297

  20. Comparative Transcriptome Analysis Reveals Different Molecular Mechanisms of Bacillus coagulans 2-6 Response to Sodium Lactate and Calcium Lactate during Lactic Acid Production

    PubMed Central

    Qin, Jiayang; Wang, Xiuwen; Wang, Landong; Zhu, Beibei; Zhang, Xiaohua; Yao, Qingshou; Xu, Ping

    2015-01-01

    Lactate production is enhanced by adding calcium carbonate or sodium hydroxide during fermentation. However, Bacillus coagulans 2-6 can produce more than 180 g/L L-lactic acid when calcium lactate is accumulated, but less than 120 g/L L-lactic acid when sodium lactate is formed. The molecular mechanisms by which B. coagulans responds to calcium lactate and sodium lactate remain unclear. In this study, comparative transcriptomic methods based on high-throughput RNA sequencing were applied to study gene expression changes in B. coagulans 2-6 cultured in non-stress, sodium lactate stress and calcium lactate stress conditions. Gene expression profiling identified 712 and 1213 significantly regulated genes in response to calcium lactate stress and sodium lactate stress, respectively. Gene ontology assignments of the differentially expressed genes were performed. KEGG pathway enrichment analysis revealed that ‘ATP-binding cassette transporters’ were significantly affected by calcium lactate stress, and ‘amino sugar and nucleotide sugar metabolism’ was significantly affected by sodium lactate stress. It was also found that lactate fermentation was less affected by calcium lactate stress than by sodium lactate stress. Sodium lactate stress had negative effect on the expression of ‘glycolysis/gluconeogenesis’ genes but positive effect on the expression of ‘citrate cycle (TCA cycle)’ genes. However, calcium lactate stress had positive influence on the expression of ‘glycolysis/gluconeogenesis’ genes and had minor influence on ‘citrate cycle (TCA cycle)’ genes. Thus, our findings offer new insights into the responses of B. coagulans to different lactate stresses. Notably, our RNA-seq dataset constitute a robust database for investigating the functions of genes induced by lactate stress in the future and identify potential targets for genetic engineering to further improve L-lactic acid production by B. coagulans. PMID:25875592

  1. A Raman spectroscopic study of glasses along the joins silica-calcium aluminate, silica-sodium aluminate, and silica-potassium aluminate

    Microsoft Academic Search

    Paul McMillan; Bernard Piriou; Alexandra Navrotsky

    1982-01-01

    Aluminosilicate glasses with compositions along the joins silica-calcium aluminate, silica sodium aluminate and silica-potassium aluminate have been prepared by conventional and solar melting techniques and studied by Raman spectroscopy. The Raman spectra of crystalline calcium aluminate, anorthite and silica polymorphs are discussed in relation to their crystal structures, and compared with the spectra of the corresponding glasses. The glass and

  2. Calcium balance and acid-base status of women as affected by increased protein intake and by sodium bicarbonate ingestion13

    Microsoft Academic Search

    Josephine Lutz

    Six women, aged 38 to 62 yr. participated in a 40-day metabolic study to investigate the effect of level of protein intake and of sodium bicarbonate ingestion on urinary calcium, net calcium balance, net renal acid excretion, and arterialized venous blood pH and bicarbonate ion concentration. The diet contained 44 g protein during the first 16 days and 102 g

  3. Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy.

    PubMed

    Houston, Jacqueline R; Maxwell, Robert S; Carroll, Susan A

    2009-01-01

    Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (+/- 0.1) x 10(-5) s(-1) for a solution:solid of 10:1 and 1.6 (+/- 0.8) x 10(-4) s(-1) for a solution:solid of 5:1 (batch mode; T = 150 degrees C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at delta iso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (+/- 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR. PMID:19144195

  4. Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy

    PubMed Central

    2009-01-01

    Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (± 0.1) × 10-5 s-1 for a solution:solid of 10:1 and 1.6 (± 0.8) × 10-4 s-1 for a solution:solid of 5:1 (batch mode; T = 150°C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at ?iso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (± 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR. PMID:19144195

  5. Synthesis and hydration behavior of calcium zirconium aluminate (Ca{sub 7}ZrAl{sub 6}O{sub 18}) cement

    SciTech Connect

    Kang, Eun-Hee [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Yoo, Jun-Sang [Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul 110-749 (Korea, Republic of)] [Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Seoul 110-749 (Korea, Republic of); Kim, Bo-Hye; Choi, Sung-Woo [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Hong, Seong-Hyeon, E-mail: shhong@snu.ac.kr [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)] [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)

    2014-02-15

    Calcium zirconium aluminate (Ca{sub 7}ZrAl{sub 6}O{sub 18}) cements were prepared by solid state reaction and polymeric precursor methods, and their phase evolution, morphology, and hydration behavior were investigated. In polymeric precursor method, a nearly single phase Ca{sub 7}ZrAl{sub 6}O{sub 18} was obtained at relatively lower temperature (1200 °C) whereas in solid state reaction, a small amount of CaZrO{sub 3} coexisted with Ca{sub 7}ZrAl{sub 6}O{sub 18} even at higher temperature (1400 °C). Unexpectedly, Ca{sub 7}ZrAl{sub 6}O{sub 18} synthesized by polymeric precursor process was the large-sized and rough-shaped powder. The planetary ball milling was employed to control the particle size and shape. The hydration behavior of Ca{sub 7}ZrAl{sub 6}O{sub 18} was similar to that of Ca{sub 3}Al{sub 2}O{sub 6} (C3A), but the hydration products were Ca{sub 3}Al{sub 2}O{sub 6}·6H{sub 2}O (C3AH6) and several intermediate products. Thus, Zr (or ZrO{sub 2}) stabilized the intermediate hydration products of C3A.

  6. Study on coordination characteristics of neptunium and uranium ions in calcium nitrate hydrate melt by Raman spectrometry and UV/Vis/NIR spectrometry

    NASA Astrophysics Data System (ADS)

    Fujii, T.; Okude, G.; Uehara, A.; Yamana, H.

    2010-03-01

    Extraction behavior of neptunium (Np) by tri-n-butyl phosphate from calcium nitrate hydrate melt was investigated. Distribution ratio of Np was found to increase with the decrease of water content. Adding nitric acid into the system resulted in an increase of the distribution ratio. In order to understand the extraction trends, Np species in the hydrate melt were analyzed by Raman spectrometry and UV/Vis/NIR spectrometry. Major fraction was assigned to be NpO22+ of Np(VI) and small fraction to be NpO2+ of Np(V). A shift of the v1 symmetric vibrational frequency of NpO22+ in nitrate media was found in Raman spectra. This suggests a coordination circumstance change of NpO22+.

  7. Synthesis of sodium caseinate-calcium carbonate microspheres and their mineralization to bone-like apatite

    NASA Astrophysics Data System (ADS)

    Xu, Zhewu; Liang, Guobin; Jin, Lin; Wang, Zhenling; Xing, Chao; Jiange, Qing; Zhang, Zhiguang

    2014-06-01

    Phosphoproteins can induce and stabilize calcium carbonate (CaCO3) vaterite, which has desirable features for high reactivity. The purpose of this study was to synthesize bioactive CaCO3 microspheres for bone regeneration. Sodium caseinate (NaCas)-containing CaCO3 microspheres, with the crystal phase of vaterite, were synthesized by fast precipitation in an aqueous solution of CaCl2, Na2CO3, and 2 mg/mL of NaCas. The uniform microspheres exhibited rougher surfaces and lower negative charges than CaCO3 particles without NaCas addition. Fourier-transform infrared spectroscopy (FT-IR) of the microspheres showed characteristic peaks or bands corresponding to phosphate and hydroxyl groups. Thermogravimetric analysis (TGA) curves exhibited approximately 5% weight loss below 600 °C due to the decomposition of NaCas. Scanning electron microscope (SEM) images showed lath-like hydroxyapatite (HAp) on the surface after soaking in simulated body fluid (SBF) at 37 °C for 5 and 10 days. Energy dispersive X-ray spectrometry (EDS) revealed that the agglomerates were composed of Ca, C, O, P, Na, and Mg elements, and the Ca/P ratios ranged from 1.53 to 1.56. X-ray diffraction (XRD) patterns exhibited peaks characteristic of hydroxyapatite. The results of this study demonstrated that the addition of NaCas induced the formation of vaterite microspheres which possesses an enhanced apatite formation after soaking in SBF at 37 °C for 5 and 10 days. These NaCas-CaCO3 microspheres may be a potential biomaterial for bone regeneration.

  8. Myocardial Function with Reduced Expression of the Sodium-Calcium Exchanger

    PubMed Central

    Jordan, Maria C.; Henderson, Scott. A.; Han, Tieyan; Fishbein, Michael C.; Philipson, Kenneth D.; Roos, Kenneth P.

    2010-01-01

    Background The complete removal of the cardiac sodium-calcium exchanger (NCX1) is associated with embryonic lethality while its overexpression is linked to heart failure. To determine whether or not a reduced expression of NCX1 is compatible with normal heart structure and function, we studied two knockout mouse models with reduced levels of NCX1: a heterozygous global knockout (HG-KO) with a 50% level of NCX1 expression in all myocytes, and a ventricular specific KO (V-KO) with NCX1 expression in only 10-20% of the myocytes. Methods and Results Both groups of mice were evaluated at baseline, after trans-aortic constriction (TAC), and after acute or chronic beta-adrenergic stimulation. At baseline, the HG-KO mice had smaller hearts and the V-KO mice had larger hearts than their wild-type (WT) controls (P<0.05). The HG-KO and their control WT mice had normal responses to TAC and beta-adrenergic stimulation. However, the V-KO group was intolerant to TAC and had a significantly (P<0.05) blunted response to beta-adrenergic stimulation as compared to the HG-KO mice and WT controls. Unlike the HG-KO mice, the V-KO mice did not tolerate chronic isoproterenol infusion. Telemetric analysis of the ECG, body temperature and activity revealed a normal diurnal rhythm in all groups of mice, but confirmed shorter QT intervals along with increased arrhythmias and reduced R/P amplitude ratios in the V-KO mice. Conclusions Though NCX1 can be reduced by ½ in all myocytes without significant functional alterations, it must be expressed in more than 20% of the myocytes to prevent severe remodeling and heart failure in mouse heart. PMID:20797603

  9. Calcium

    MedlinePLUS

    ... loss. Some clinical research shows that increasing calcium consumption from dairy products such as yogurt seems to ... and vitamin D. For weight loss, increasing calcium consumption from dairy products to total intake of 500- ...

  10. Calcium

    MedlinePLUS

    ... strong bones and teeth. Why Do I Need Calcium? Bones grow rapidly during adolescence, and teens need ... salmon with bones. Almond milk. Back Continue Working Calcium Into Your Diet Looking for ways to up ...

  11. Calcium

    MedlinePLUS

    ... and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system. It is important to get plenty of calcium in the foods you eat. Foods rich in calcium include Dairy ...

  12. Crystal structures of hydrates of simple inorganic salts. II. Water-rich calcium bromide and iodide hydrates: CaBr2 · 9H2O, CaI2 · 8H2O, CaI2 · 7H2O and CaI2 · 6.5H2O.

    PubMed

    Hennings, Erik; Schmidt, Horst; Voigt, Wolfgang

    2014-09-01

    Single crystals of calcium bromide enneahydrate, CaBr(2) · 9H2O, calcium iodide octahydrate, CaI(2) · 8H2O, calcium iodide heptahydrate, CaI(2) · 7H2O, and calcium iodide 6.5-hydrate, CaI(2) · 6.5H2O, were grown from their aqueous solutions at and below room temperature according to the solid-liquid phase diagram. The crystal structure of CaI(2) · 6.5H2O was redetermined. All four structures are built up from distorted Ca(H2O)8 antiprisms. The antiprisms of the iodide hydrate structures are connected either via trigonal-plane-sharing or edge-sharing, forming dimeric units. The antiprisms in calcium bromide enneahydrate are monomeric. PMID:25186361

  13. Trichloroethylene decomposition and in-situ dry sorption of Cl-products by calcium oxides prepared from hydrated limes.

    PubMed

    Gotoh, Yoshimi; Iwata, Goichi; Choh, Kyaw; Kubota, Mitsuhiro; Matsuda, Hitoki

    2011-10-01

    A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours. It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K. It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed. PMID:21821273

  14. Synthesis and nano-mechanical characterization of calcium-silicate-hydrate (C-S-H) made with 1.5 CaO/SiO{sub 2} mixture

    SciTech Connect

    Foley, Emmy M. [Arizona Public Service, Wintersburg, AZ 85354 (United States)] [Arizona Public Service, Wintersburg, AZ 85354 (United States); Kim, Jung J. [Department of Civil and Environmental Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)] [Department of Civil and Environmental Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Reda Taha, M.M., E-mail: mrtaha@unm.edu [Department of Civil Engineering, MSC01 1070, 1 University of New Mexico, Albuquerque, NM 87131-0001 (United States)

    2012-09-15

    In this study, calcium silicate hydrate (C-S-H) is synthesized and characterized. C-S-H slurry was made with calcium oxide (CaO) to micro-silica (SiO{sub 2}) mixture ratio of 1.5 and enough deionized water. The slurry was continuously mixed for 7 days, then the excess water was removed. Two methods of drying were implemented: one method used the standard d-dry technique and the other was equilibrated to 11% relative humidity (RH). The dried powders were characterized using thermo gravimetric analysis (TGA), X-ray diffraction analysis (XRDA), and {sup 29}Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy. The stoichiometric formulas of synthetic C-S-H powders dried to d-dry and 11% RH in this study were approximated as C{sub 1.2}SH{sub 0.7} and C{sub 1.2}SH{sub 2.4} respectively. The powders were then compacted to create specimens with porosities similar to C-S-H in hydrated cement. The specimens underwent nanoindentation to mechanically characterize C-S-H. The experiments provide insight on the nanoscale mechanical characteristics of C-S-H.

  15. Aqueous solubility diagrams for cementitious waste stabilization systems. 4. A carbonation model for Zn-doped calcium silicate hydrate by Gibbs energy minimization.

    PubMed

    Kulik, Dmitrii A; Kersten, Michael

    2002-07-01

    A thermodynamic Gibbs energy minimization (GEM) solid solution-aqueous solution (SSAS) equilibrium model was used to determine the solubility of Zn from calcium silicate hydrate (CSH) phases doped with 0, 0.1, 1, 5, and 10% Zn at a unity (Ca+Zn)/Si molar ratio. Both the stoichiometry and standard molar Gibbs energy (G(o)298) of the Zn-bearing end-member in the ideal ternary Zn-bearing calcium silicate hydrate (CZSH) solid solution were determined by a "dual-thermodynamic" (GEM-DT) estimation technique. The SSAS model reproduces a complex sequence of reactions suggested to occur in a long-term weathering scenario of cementitious waste forms at subsurface repository conditions. The GEM model of CZSH leaching at several Zn loadings and solid/water (s/w) ratios in a C02-free system showed that, upon complete dissolution of portlandite and calcium zincate phases at decreasing s/w < 0.01 mol x kg(H2O)(-1), the total dissolved concentrations Si(aq), Ca(aq), and Zn(aq) are controlled by a CZSH solid solution of changing composition, with a trough-like Znaq drop by 2-3 orders of magnitude. Carbonation was simulated in another GEM model run series by CO2 titration of the system with initial s/w approximately 0.9 mol/kg(H2O). Formation of (Ca,Zn)-CO3 nonideal solid solution was predicted already at early reaction stage in the presence of both portlandite and calcium zincate hydrate phases. Upon their disappearance, pH, Zn(aq), C(aq), and fCO2 were predicted to change due to the incongruent dissolution of two concurrent CZSH-I and CZSH-II solid solutions, until the total re-partitioning of Ca and Zn into a carbonate solid solution coexisting with amorphous silica at fCO2 > 0.1 bar. Along this solid-phase transition, dissolved Zn(aq) concentrations follow a highly nonlinear trend. The model results predict that at low to moderate Zn loading (< or = 1% per mole Si), CZSH-type compounds can efficiently immobilize Zn in the near field of a cement-stabilized waste repository. PMID:12144269

  16. Phylogeny Unites Animal Sodium Leak Channels with Fungal Calcium Channels in an Ancient, Voltage-Insensitive Clade

    PubMed Central

    Liebeskind, Benjamin J.; Hillis, David M.; Zakon, Harold H.

    2012-01-01

    Proteins in the superfamily of voltage-gated ion channels mediate behavior across the tree of life. These proteins regulate the movement of ions across cell membranes by opening and closing a central pore that controls ion flow. The best-known members of this superfamily are the voltage-gated potassium, calcium (Cav), and sodium (Nav) channels, which underlie impulse conduction in nerve and muscle. Not all members of this family are opened by changes in voltage, however. NALCN (NA+ leak channel nonselective) channels, which encode a voltage-insensitive “sodium leak” channel, have garnered a growing interest. This study examines the phylogenetic relationship among Nav/Cav voltage-gated and voltage-insensitive channels in the eukaryotic group Opisthokonta, which includes animals, fungi, and their unicellular relatives. We show that NALCN channels diverged from voltage-gated channels before the divergence of fungi and animals and that the closest relatives of NALCN channels are fungal calcium channels, which they functionally resemble. PMID:22821012

  17. 21 CFR 180.37 - Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED IN FOOD OR IN CONTACT WITH...Specific Requirements for Certain Food Additives § 180.37 Saccharin, ammonium...saccharin, and sodium saccharin. The food additives saccharin, ammonium...

  18. 21 CFR 180.37 - Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED IN FOOD OR IN CONTACT WITH...Specific Requirements for Certain Food Additives § 180.37 Saccharin, ammonium...saccharin, and sodium saccharin. The food additives saccharin, ammonium...

  19. 21 CFR 180.37 - Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED IN FOOD OR IN CONTACT WITH...Specific Requirements for Certain Food Additives § 180.37 Saccharin, ammonium...saccharin, and sodium saccharin. The food additives saccharin, ammonium...

  20. 21 CFR 180.37 - Saccharin, ammonium saccharin, calcium saccharin, and sodium saccharin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED IN FOOD OR IN CONTACT WITH...Specific Requirements for Certain Food Additives § 180.37 Saccharin, ammonium...saccharin, and sodium saccharin. The food additives saccharin, ammonium...

  1. Influence of Pyrethroid Insecticides on Sodium and Calcium Influx in Neocortical Neurons

    EPA Science Inventory

    Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Using murine neocortical neurons in primary culture, we have compared the ability of 11 structurally diverse pyrethroid insecticides to evoke Na+ ...

  2. Intraoral evaluation of mineralization of cosmetic defects by a toothpaste containing calcium, fluoride, and sodium bicarbonate.

    PubMed

    Litkowski, Leonard J; Quinlan, Kathleen B; Ross, David R; Ghassemi, Annahita; Winston, Anthony; Charig, Andrew; Flickinger, Mark; Vorwerk, Linda

    2004-09-01

    New dual-phase fluoride toothpastes that contain soluble calcium, phosphate, and baking soda have recently been introduced into the market. These toothpastes are designed to fill in small surface defects in tooth enamel and thereby enhance tooth esthetics such as gloss. This two-part study was designed to assess these superficial mineralizing effects from using one of these products compared with an experimental calcium-containing, bicarbonate-free formulation and a conventional fluoride toothpaste using an intraoral model. Enamel specimens with 4 types of defects were mounted into an intraoral appliance and placed in the mouths of volunteers for 1 month. The four types of defects were whitening toothpaste abrasion, coarse abrasion, natural dimpling, and acid etching. Before and after intraoral exposure, scanning electron microscope photographs of the specimens were made. The surface microhardness of the acid-etched specimens also was determined. The volunteers brushed their specimens twice daily with one of three randomly assigned toothpastes. The toothpastes were a two-phase, calcium-containing, bicarbonate-based toothpaste; an experimental, two-phase, calcium-containing, bicarbonate-free toothpaste; and a conventional toothpaste. Only the calcium-containing toothpastes showed unequivocal signs of mineral deposition into surface defects, leading to smoothing of the enamel. All three products significantly increased the hardness of the etched enamel, presumably because of fluoride. However, only the two calcium-containing toothpastes gave significantly greater hardness increases than the conventional toothpaste; the specimens treated with a conventional toothpaste were indistinguishable from those treated with saliva. PMID:15645904

  3. Effect of modification of hydroxyapatite\\/collagen composites with sodium citrate, phosphoserine, phosphoserine\\/RGD-peptide and calcium carbonate on bone remodelling

    Microsoft Academic Search

    Wolfgang Schneiders; Antje Reinstorf; Wolfgang Pompe; Rene Grass; Achim Biewener; Michael Holch; Hans Zwipp; Stefan Rammelt

    2007-01-01

    This study describes the early interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (HA\\/ Coll) and its modifications with sodium citrate (CI), calcium carbonate (CA), phosphoserine (P) and phosphoserine plus RGD-peptide (RGD). Cylindrical implants of HA\\/Coll and its modifications were inserted into the tibia of Wistar rats. We analysed 6 specimens per group at

  4. Pilot Study of Bioaccumulation and Distribution of Cesium, Potassium, Sodium and Calcium in King Oyster Mushroom (Pleurotus Eryngii) Grown Under Controlled Conditions

    Microsoft Academic Search

    Gra?yna Bystrzejewska-Piotrowska; Dariusz Pianka; Micha? A. Baza?a; Romuald St?borowski; José L. Manjón; Pawel L. Urban

    2008-01-01

    This pilot study presents preliminary results on interrelations between alkali and alkaline earth elements during their transfer to mycelium and fruitbodies of saprophytic fungi. The accumulation and distribution of four elements (cesium, potassium, sodium, and calcium) was evaluated in king oyster mushroom (Pleurotus eryngii) cultivated under controlled conditions. Elemental composition of caps, stipes, and the substrate was analyzed by atomic

  5. Small-scale pilot evaluation of calcium- and sodium-based sorbents for dry SO/sub 2/ removal

    SciTech Connect

    Jorgensen, C.; Chang, J.C.S.; Brna, T.G.; Sedman, C.B.

    1987-01-01

    A 100 m/sup 3//h pilot facility incorporating a spray dryer, a sorbent injection system, a duct section, and a pulse jet baghouse or cyclone separator was used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SO/sub 2/ in the concentration range of 1000-2500 ppm. The specific sorbents selected for testing were based on earlier reported sand-bed reactor (0.3 m/sup 3//h) tests. The performance of these sorbents is compared in terms of SO/sub 2/ removal and stoichiometry with that obtained using conventional slaked lime in spray drying or dry injection at similar conditions.

  6. Calcium Alginate-Neusilin US2 Nanocomposite Microbeads for Oral Sustained Drug Delivery of Poor Water Soluble Drug Aceclofenac Sodium

    PubMed Central

    Mallappa, Manjanna Kolammanahalli; Kesarla, Rajesh; Banakar, Shivakumar

    2015-01-01

    The aim of the present study was to formulate and investigate the calcium alginate- (CA-) Neusilin US2 nanocomposite microbeads containing preconcentrate of aceclofenac sodium (ACF-Na) liquid microemulsion (L-ME) for enhancement of oral bioavailability. The preconcentrate L-ME is prepared by using Labrafac PG, Labrasol, and Span 80 as oil, surfactant, and cosurfactant, respectively. The solid CA nanocomposite microbeads of L-ME prepared by microemulsification internal gelation technique using sodium alginate (SA) gelling agent, Neusilin US2 as adsorbent, and calcium chloride as crosslinking agent. L-ME has good thermodynamic stability; globule size was found to be 32.4?nm with polydispersity index 0.219 and ?6.32?mV zeta potential. No significant interactions of excipients, drug in the formulations observed by FT-IR, DSC and XPRD. The concentration of SA and Neusilin US2 influences the flow properties, mean particle size, mechanical strength, drug entrapment efficiency, and percentage of drug release. All the formulations show minimum drug release in simulated gastric fluid (SGF) pH 1.2 for initial 2?h, maximum drug release in pH 6.8 phosphate buffer solution (PBS) at 6?h, followed by sustaining in simulated intestinal fluid (SIF) of pH 7.4 up to 12?h. The interaction of SA with Neusilin US2 creates a thick thixotropic gel network structure which acts as barrier to control the release of drug in the alkaline pH environment. Neusilin US2 is a novel filler used to convert L-ME into solid nanocomposite microbeads to enhance dissolution rate of poor water soluble drugs sustaining the drug release for prolonged period of time.

  7. Effects of moderate static magnetic fields on the voltage-gated sodium and calcium channel currents in trigeminal ganglion neurons.

    PubMed

    Lu, Xiao-Wen; Du, Li; Kou, Liang; Song, Ning; Zhang, Yu-Jiao; Wu, Min-Ke; Shen, Jie-Fei

    2014-04-01

    Abstract Aim: To study the effects of static magnetic fields (SMF) on the electrophysiological properties of voltage-gated sodium and calcium channels on trigeminal ganglion (TRG) neurons. Methods: Acutely dissociated TRG neurons of neonatal SD rats were exposed to 125-mT and 12.5-mT SMF in exposure devices and whole-cell patch-clamp recordings were carried out to observe the changes of voltage-gated sodium channels (VGSC) and calcium channels (VGCC) currents, while laser scanning confocal microscopy was used to detect intracellular free Ca(2+) concentration in TRG neurons, respectively. Results: (1) No obvious change of current-voltage (I-V) relationship and the peak current densities of VGSC and VGCC currents were found when TRG neurons were exposed to 125-mT and 12.5-mT SMF. However, the activation threshold, inactivation threshold and velocity of the channel currents above were significantly altered by 125-mT and 12.5-mT SMF. (2) The fluctuation of intracellular free Ca(2+) concentration within TRG neurons were slowed by 125-mT and 12.5-mT SMF. When SMF was removed, the Ca(2+) concentration level showed partial recovery in the TRG neurons previously exposed by 125-mT SMF, while there was a full recovery found in 12.5-mT-SMF-exposed neurons. Conclusions: Moderate-intensity SMF could affect the electrophysiological characteristics of VGCS and VGCC by altering their activation and inactivation threshold and velocity. The fluctuations of intracellular free Ca(2+) caused by SMF exposure were not permanent in TRG neurons. PMID:24712748

  8. Calcium Alginate-Neusilin US2 Nanocomposite Microbeads for Oral Sustained Drug Delivery of Poor Water Soluble Drug Aceclofenac Sodium.

    PubMed

    Mallappa, Manjanna Kolammanahalli; Kesarla, Rajesh; Banakar, Shivakumar

    2015-01-01

    The aim of the present study was to formulate and investigate the calcium alginate- (CA-) Neusilin US2 nanocomposite microbeads containing preconcentrate of aceclofenac sodium (ACF-Na) liquid microemulsion (L-ME) for enhancement of oral bioavailability. The preconcentrate L-ME is prepared by using Labrafac PG, Labrasol, and Span 80 as oil, surfactant, and cosurfactant, respectively. The solid CA nanocomposite microbeads of L-ME prepared by microemulsification internal gelation technique using sodium alginate (SA) gelling agent, Neusilin US2 as adsorbent, and calcium chloride as crosslinking agent. L-ME has good thermodynamic stability; globule size was found to be 32.4?nm with polydispersity index 0.219 and -6.32?mV zeta potential. No significant interactions of excipients, drug in the formulations observed by FT-IR, DSC and XPRD. The concentration of SA and Neusilin US2 influences the flow properties, mean particle size, mechanical strength, drug entrapment efficiency, and percentage of drug release. All the formulations show minimum drug release in simulated gastric fluid (SGF) pH 1.2 for initial 2?h, maximum drug release in pH 6.8 phosphate buffer solution (PBS) at 6?h, followed by sustaining in simulated intestinal fluid (SIF) of pH 7.4 up to 12?h. The interaction of SA with Neusilin US2 creates a thick thixotropic gel network structure which acts as barrier to control the release of drug in the alkaline pH environment. Neusilin US2 is a novel filler used to convert L-ME into solid nanocomposite microbeads to enhance dissolution rate of poor water soluble drugs sustaining the drug release for prolonged period of time. PMID:25802761

  9. A study in the rat of the renal actions of nitrendipine and diltiazem on the adrenergic regulation of calcium and sodium reabsorption.

    PubMed

    Johns, E J; Manitius, J

    1986-09-01

    In pentobarbitone-anaesthetized rats, intravenous administration of diltiazem at 5 micrograms kg-1 min-1 did not change blood pressure or renal blood flow but increased glomerular filtration rate by approximately 16%, urine flow by 85%, calcium excretion by 151% and absolute and fractional sodium excretions by 100% and 69%, respectively. A similar pattern of responses was obtained in renally denervated animals, except that calcium excretion did not change statistically. Diltiazem given at 20 micrograms kg-1 min-1 into renally innervated and denervated groups of animals depressed blood pressure between 15-17 mmHg but had no effect on renal haemodynamic or tubular function. Nitrendipine administered at 0.5 microgram kg-1 min-1 to renally innervated and denervated animals significantly depressed blood pressure in intact animals by 6 mmHg and in both groups did not change renal haemodynamics but caused similar increases in urine flow of between 79-98%, calcium excretion of between 87 and 125%, absolute sodium excretion of between 108 and 140% and fractional sodium excretion of between 83 and 170%. Infusion of nitrendipine at 1.0 micrograms kg-1 min-1 into intact or renally denervated animals decreased blood pressure by 18-20 mmHg and increased urine flow by 84-111%, calcium excretion by 85%, absolute sodium excretion by 81-137% and fractional sodium excretion by 52-102%. Stimulation of the renal nerves at low frequencies (0.8 to 1.5 Hz) caused minimal changes in renal haemodynamics but decreased urine flow by 27%, calcium excretion by 35%, absolute and fractional sodium excretions 32% and 36%, respectively. In different groups of animals given either diltiazem at 20 pg kg- I min' or nitrendipine at 0.5 pg kg'- min' or 1.0 fg kg'- min', a similar degree of renal nerve stimulation caused an identical pattern of excretory responses of similar magnitude to those obtained in the absence of drug. 4 The calciuretic, diuretic and natriuretic activities of diltiazem and nitrendipine were not dependent on renal nerves and probably represented a direct action on the tubular reabsorptive processes of these ions. The renal nerve-induced increases in tubular calcium and sodium reabsorption indicate that these alpha-adrenoceptor-mediated responses are not dependent on the inward movement of calcium PMID:3801781

  10. Sodium helps our body balance fluid levels and maintain hydration. Each person's sodium requirement varies but one thing we do know is that Americans are consuming

    E-print Network

    Garfunkel, Eric

    time for physical activity along with taking care of your job, your family and yourself. Research shows be Caused by Lack of Sleep? 2 Oral Health and Nutrition in Older Adults 3 Don't Sabotage Your Healthy of sodium or other names for the #12;Does lack of sleep really lead to unhealthy eating and decreased

  11. The substitution of sodium for calcium in the mineral nutrition of cotton

    E-print Network

    Whitenberg, David Calvin

    1959-01-01

    . All of the plants were injured to a greater or lesser ex- tent when he attempted to substitute ammonium, barium, strontium, ces- ium, rubidium, or lithium salts for sodium. It was further found that the cells of Ulva lactuca failed to divide...

  12. Influence of sodium dodecyl sulfate and static magnetic field on the properties of freshly precipitated calcium carbonate.

    PubMed

    Chibowski, Emil; Szczes, Aleksandra; Holysz, Lucyna

    2005-08-30

    Properties of calcium carbonate precipitated from aqueous solutions of CaCl(2) and Na(2)CO(3) in the presence of sodium dodecyl sulfate (SDS) and S-S 0.1 T magnetic field (MF) were studied. The nucleation and precipitation processes of CaCO(3) were investigated by pH and zeta potential measurements at 20 +/- 1 degrees C up to 2 h after mixing the solutions. Also the amounts of calcium carbonate deposited on the glass surfaces and its structure were examined. It was found that SDS influences the kinetics of precipitation, crystallographic forms, and crystal size of CaCO(3). The SDS effects are more pronounced in MF presence. A small amount of SDS accelerates transformation of vaterite into calcite, whereas increasing surfactant concentration moderates such a transformation. On the other hand, in all the systems, MF in the presence of SDS causes a slower transformation of vaterite into calcite. These effects are reflected in pH and zeta potential changes, although there is no clear dependence between the SDS amount present during the precipitation and changes of the parameters investigated. It seems that MF effect is most significant at a defined optimal SDS concentration. The results, however, do not allow suggestion of any detailed mechanism of the field interaction. PMID:16114911

  13. Explosive vaporization of crystal water on temperature-programmed heating of a thin film of hydrated calcium nitrate

    NASA Astrophysics Data System (ADS)

    Asada, Hiromu; Udaka, Masayuki; Kawano, Hiroyuki

    1994-11-01

    The temperature-programmed vaporization of crystal water in vacuum was studied for a thin film of Ca(NO3)*nH2O prepared on a nichrome ribbon heater. The mass-spectrometric signal intensity of vaporized water measured as a function of the film temperature reveals a spectrum consisting of two sharp peaks, in remarkable contrast to the broad spectra observed for other kinds of hydrated inorganic salts. The low-temperature peak exhibits normal kinetic features which seem to be consistent with direct emission of water molecules from the crystalline lattice of the hydrated salt. However, the high-temperature peak appears in an explosive manner, and its intensity relative to the low-temperature peak increases with increasing film thickness or with increasing heating rate. These features of the high-temperature peak suggest the occurrence of a kinetic phase transition of the hydrated salt from a crystalline state to a non-crystalline state, rather than step-wise dehydration of the crystalline salt.

  14. Incorporation of zinc into calcium silicate hydrates, Part I: formation of C-S-H(I) with C/S=2/3 and its isochemical counterpart gyrolite

    SciTech Connect

    Stumm, Andreas [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)]. E-mail: andreas.stumm@itc-wgt.fzk.de; Garbev, Krassimir [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Beuchle, Guenter [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Black, Leon [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Materials Research Institute, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Stemmermann, Peter [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Nueesch, Rolf [Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2005-09-01

    We have investigated the incorporation of zinc into both nanocrystalline and crystalline calcium silicate hydrates with starting C/S ratios of 2/3 (0.66). Zinc was added replacing calcium in the starting mixtures [Zn/(Zn+Ca)=0-1/4; 0-10 wt.% Zn], and the resultant phases were characterised using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), differential thermal analysis-thermogravimetry (DTA-TG) and environmental scanning electron microscopy (ESEM). In both groups of samples, increasing zinc content led to gradual structural changes, until eventually a second phase was formed. Zinc was incorporated to similar limits in both sets of samples. The thermal stability of the structures increased to a certain zinc content, beyond which there was structural destabilisation. Zinc incorporation is possible up to {approx}6 wt.%. Our observations strongly indicate similar zinc incorporation mechanisms in both sample series, namely incorporation of zinc into the interlayer of C-S-H(I) and the X-sheet of gyrolite for nanocrystalline and crystalline samples, respectively.

  15. Use of aqueous solutions of sodium alginate and calcium acetate as quenching liquids

    Microsoft Academic Search

    M. G. Kurmashov

    1982-01-01

    Aqueous solutions of SA are prepared from a film of it obtained from an algal extract. The algai extract is prepared from seaweed of the species Lc~inaria saccharina and digitata. For the quenching solution 1--3% of the dried seaweeds is infused for 3--5 days in a 1% aqueous sodium carbonate solution. To obtain the SA film sulfuric or hydrochloric acid

  16. A realistic molecular model of cement hydrates Roland J.-M. Pellenqa,b

    E-print Network

    Van Vliet, Krystyn J.

    of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay be, a complex hydrated oxide called calcium-silicate-hydrate (C­S­H) precipitates as nanoscale clusters calcium silicate hydrates, based on HFW Taylor's postulate that real C-S-H was a structurally imperfect

  17. Interaction between alpha-calcium sulfate hemihydrate and superplasticizer from the point of adsorption characteristics, hydration and hardening process

    Microsoft Academic Search

    Guan Baohong; Ye Qingqing; Zhang Jiali; Lou Wenbin; Wu Zhongbiao

    2010-01-01

    Superplasticizers (SPs), namely sulfonated melamine formaldehyde (SMF) and polycarboxylate (PC), were independently admixed with alpha-calcium sulfate hemihydrate based plaster to improve the material's performance. SMF and PC gave, respectively, 38% and 25% increases in the 2 h bending strength at the optimum dosages of 0.5 wt.% and 0.3 wt.%, which are determined essentially by the maximum water-reducing efficiency. The peak

  18. Interaction between ?-calcium sulfate hemihydrate and superplasticizer from the point of adsorption characteristics, hydration and hardening process

    Microsoft Academic Search

    Baohong Guan; Qingqing Ye; Jiali Zhang; Wenbin Lou; Zhongbiao Wu

    2010-01-01

    Superplasticizers (SPs), namely sulfonated melamine formaldehyde (SMF) and polycarboxylate (PC), were independently admixed with ?-calcium sulfate hemihydrate based plaster to improve the material's performance. SMF and PC gave, respectively, 38% and 25% increases in the 2h bending strength at the optimum dosages of 0.5wt.% and 0.3wt.%, which are determined essentially by the maximum water-reducing efficiency. The peak shift of binding

  19. Diffusion of sodium, potassium, calcium, manganese, and radon in tuff and clinoptilolite under leaching

    NASA Astrophysics Data System (ADS)

    Dikii, N. P.; Dovbnya, A. N.; Lyashko, Yu. V.; Medvedev, D. V.; Medvedeva, E. P.; Uvarov, V. L.; Achkasov, K. V.

    2011-07-01

    Nuclear physics methods are used to determine the diffusion coefficients of Na, Ca, Mn, K, and 222Rn in clinoptilolite (Sokirnitsa occurrence, Ukraine) and in natural tuff (Yucca Mountain, Nevada, United States) and in tuff irradiated by ?-quanta ( E max = 23 MeV) to a dose of 107 Gy at a leaching temperature of 37°C. The diffusion coefficients of sodium and potassium in clinoptilolite are found to differ considerably: 4 × 10-17 and 2 × 10-20 m2/s, respectively. This indicates the influence of aquacomplexes on the cation transfer. The diffusion coefficient of radon in these materials is determined: in clinoptilolite it equals 2.5 × 10-12 m2/s.

  20. Synaptic sodium spikes trigger long-lasting depolarizations and slow calcium entry in rat olfactory bulb granule cells.

    PubMed

    Egger, Veronica

    2008-04-01

    In the mammalian olfactory bulb, axonless granule cells mediate self- and lateral inhibitory interactions between mitral/tufted cells via reciprocal dendrodendritic synapses. Synaptic output from granule cells occurs on both fast and slow timescales, allowing for multiple granule cell functions during olfactory processing. We find that granule cell sodium action potentials evoked by synaptic activation of the sensory input via mitral/tufted cells are followed by a long-lasting depolarization that is not observed after current-evoked action potentials or large excitatory postsynaptic potentials in the same cell. Using two-photon imaging in acute rat brain slices, we demonstrate that this prolonged electrical response is paralleled by an unusual, long-lasting postsynaptic calcium signal. We find that this slow synaptic Ca(2+) signal requires sequential activation of NMDA receptors, a nonselective cation conductance I(CAN) and T-type voltage-dependent Ca(2+) channels. Remarkably, T-type Ca(2+) channels are of critical importance for the 'globalization' of Ca(2+) transients. In individual active spines, the local synaptic Ca(2+) signal summates at least linearly with the global spike-mediated Ca(2+) signal. We suggest that this robust slow synaptic Ca(2+) signal triggers dendritic transmitter release and thus contributes to slow synaptic output of the granule cell. Therefore, the synaptic sodium spike signal could represent a special adaptation of granule cells to the wide range of temporal requirements for their dendritic output. Our findings demonstrate with respect to neuronal communication in general that action potentials evoked by somatic current injection may lack some of the information content of 'true' synaptically evoked spikes. PMID:18412627

  1. Effect of polysaccharides on the hydration of cement paste at early A. Peschard, A. Govin*

    E-print Network

    Paris-Sud XI, Université de

    on the hydration of silicate phase in presence of admixtures were devoted to the determination of calcium hydroxide, calcium silicate phase (C3S) particles are covered by flaky calcium silicate hydrate (CSH), i of monosaccharides or sugar acids on cement or single phase hydration [8-11]. Influence of such admixtures on Calcium

  2. Inhibition of nitrite-induced toxicity in channel catfish by calcium chloride and sodium chloride

    USGS Publications Warehouse

    Tommasso J.R., Wright, M. I.; Simco, B.A.; Davis, K.B.

    1980-01-01

    Environmental chloride has been shown to inhibit methemoglobin formation in fish, thereby offering a protective effect against nitrite toxicity. Channel catfish (Ictalurus punctatus) were simultaneously exposed to various environmental nitrite and chloride levels (as either CaCl2 or NaCl) in dechlorinated tap water (40 mg/L total hardness, 47 mg/L alkalinity, 4 mg/L chloride, pH = 6.9-7.1, and temperature 21-24°C). Methemoglobin levels in fish simultaneously exposed to 2.5 mg/L nitrite and up to 30 mg/L chloride as either CaCl2 or NaCl were similar but significantly lower than in unprotected fish. Exposure to 10 mg/L nitrite and 60 mg/L chloride resulted in methemoglobin levels similar to those of the controls; most unprotected fish died. Fish exposed to 10 mg/L nitrite had significantly lower methemoglobin levels when protected with 15.0 mg/L chloride as CaCl2 than with NaCl. Fish exposed to nitrite in the presence of 60 mg/L chloride (as either CaCl2 or NaCl) had similar 24-h LC50 values that were significantly elevated above those obtained in the absence of chloride. Calcium had little effect on tolerance to nitrite toxicity in channel catfish in contrast to its large effect reported in steelhead trout (Salmo gairdneri).

  3. Complete Atrial-Specific Knockout of Sodium-Calcium Exchange Eliminates Sinoatrial Node Pacemaker Activity

    PubMed Central

    Groenke, Sabine; Larson, Eric D.; Alber, Sarah; Zhang, Rui; Lamp, Scott T.; Ren, Xiaoyan; Nakano, Haruko; Jordan, Maria C.; Karagueuzian, Hrayr S.; Roos, Kenneth P.; Nakano, Atsushi; Proenza, Catherine; Philipson, Kenneth D.; Goldhaber, Joshua I.

    2013-01-01

    The origin of sinoatrial node (SAN) pacemaker activity in the heart is controversial. The leading candidates are diastolic depolarization by “funny” current (If) through HCN4 channels (the “Membrane Clock“ hypothesis), depolarization by cardiac Na-Ca exchange (NCX1) in response to intracellular Ca cycling (the "Calcium Clock" hypothesis), and a combination of the two (“Coupled Clock”). To address this controversy, we used Cre/loxP technology to generate atrial-specific NCX1 KO mice. NCX1 protein was undetectable in KO atrial tissue, including the SAN. Surface ECG and intracardiac electrograms showed no atrial depolarization and a slow junctional escape rhythm in KO that responded appropriately to ?-adrenergic and muscarinic stimulation. Although KO atria were quiescent they could be stimulated by external pacing suggesting that electrical coupling between cells remained intact. Despite normal electrophysiological properties of If in isolated patch clamped KO SAN cells, pacemaker activity was absent. Recurring Ca sparks were present in all KO SAN cells, suggesting that Ca cycling persists but is uncoupled from the sarcolemma. We conclude that NCX1 is required for normal pacemaker activity in murine SAN. PMID:24278453

  4. Effect of Sodium and Calcium Carbonates on Milk Production and Composition of Milk, Blood, and Rumen Contents of Cows Fed Grain Ad Libitum with Restricted Roughage1

    Microsoft Academic Search

    R. S. Emery; L. D. Brown; J. W. Thomas

    1964-01-01

    SUMMARY Six cows were used in a Latin square design consisting of three periods of 28 days each and three treatments, grain plus sodium bicarbonate (1 lb\\/day), grain plus calcium carbonate (0.6 lb\\/day), and grain alone. Roughage was restricted to 2 lb hay\\/day and grain was fed ad libitum. Similarly, two groups of five cows each were used in a

  5. Lead bismuth calcium sodium phosphate: Pb4.6Bi0.4Ca2.6Na2.4(PO4)6.

    PubMed

    Hamdi, Besma; Savariault, Jean-Michel; El-Feki, Hafed; Ben Salah, Abdelhamid

    2004-01-01

    The title compound, lead bismuth calcium sodium phosphate, Pb(4.6)Bi(0.4)Ca(2.6)Na(2.4)(PO(4))(6) crystallizes in the apatite structure type, with vacancies in sites 2a or 2b that are normally occupied by anions. The fact that the Bi and Pb ions are mainly localized in the 6h sites confirms the electron lone-pair influence on the apatite structure. PMID:14712014

  6. Small-scale pilot evaluation of calcium- and sodium-based sorbents for dry SOâ removal. Report for January-December 1986

    Microsoft Academic Search

    C. Jorgensen; J. C. S. Chang; T. G. Brna; C. B. Sedman

    1987-01-01

    The paper discusses a 100 cu m\\/h pilot facility (consisting of a spray dryer, a sorbent injection system, a duct section, and a pulse-jet baghouse or cyclone separator) used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SOâ in the concentration range of 1000-2500 ppm. The sorbents tested were based on earlier-reported sand-bed reactor

  7. Dietary Intake Ratios of Calcium-to-Phosphorus and Sodium-to-Potassium Are Associated with Serum Lipid Levels in Healthy Korean Adults

    PubMed Central

    Bu, So-Young; Kang, Myung-Hwa; Kim, Eun-Jin; Choi, Mi-Kyeong

    2012-01-01

    The purpose of this study was to identify food sources for major minerals such as calcium (Ca), phosphorus (P), sodium (Na) and potassium (K), and to evaluate the relationship between dietary intake of these minerals and serum lipids in healthy Korean adults. A total of 132 healthy men and women completed a physical examination and dietary record and provided blood samples for lipid profile analysis. Results showed the following daily average mineral intakes: 373.4 mg of calcium, 806.0 mg of phosphorous, 3685.8 mg of sodium, and 1938.3 mg of potassium. The calcium-to-phosphorus and sodium-to-potassium ratio was about 0.5 and 2.0, respectively. The primary sources for each mineral were: vegetables (24.9%) and fishes (19.0%) for calcium, grains (31.4%) for phosphorus, seasonings (41.6%) and vegetables (27.0%) for sodium, and vegetables (30.6%) and grains (18.5%) for potassium. The correlation analysis, which has been adjusted for age, gender, total food consumption, and energy intake, showed significantly positive correlations between Ca/P and serum HDL cholesterol levels, between Na intake and the level of serum total cholesterol, and between Na/K and the level of serum cholesterol and LDL cholesterol. Our data indicates that the level of mineral consumption partially contributes to serum lipid profiles and that a diet consisting of a low Ca/P ratio and a high Na/K ratio may have negative impacts on lipid metabolism. PMID:24471069

  8. Calcium H & K and sodium D absorption induced by the interstellar and circumgalactic media of the Milky Way

    E-print Network

    Murga, Maria; Ménard, Brice; Lan, Ting-Wen

    2015-01-01

    We map out calcium II & sodium I absorption (Fraunhofer H, K & D lines) induced by both the interstellar medium and the circumgalactic medium of the Milky Way. Our measurements cover more than $9000$ deg$^2$ and make use of about $300,000$ extragalactic spectra from the Sloan Digital Sky Survey. We present absorption maps for these two species and then compare their distributions to those of neutral hydrogen and dust. We show that the abundance of Na I with respect to neutral hydrogen stays roughly constant in different environments, while that of Ca II decreases with hydrogen column density. Studying how these tracers vary as a function of velocity, we show that, on average, the N(Na I)/N(Ca II) ratio decreases at higher velocity with respect to the local standard of rest, similar to the local Routly-Spitzer effect but seen on Galactic scale. We show that it is likely caused by higher gas/dust density at lower velocity. Finally, we show that Galactic Ca II and Na I absorption needs to be taken into a...

  9. Conditional knockout of smooth muscle sodium calcium exchanger type?1 lowers blood pressure and attenuates Angiotensin II?salt hypertension

    PubMed Central

    Wang, Youhua; Chen, Ling; Li, Meng; Cha, Helen; Iwamoto, Takahiro; Zhang, Jin

    2015-01-01

    Abstract The functions of smooth muscle sodium calcium exchanger (NCX) in the vasculature are controversial and poorly understood. To determine the possible roles of NCX in the vascular phenotype and function, we developed a novel mouse model (SM?NCX1 KO) in which the smooth muscle?specific NCX type?1 (NCX1) was conditionally knocked out using tamoxifen?inducible Cre?loxP recombination technique. SM?NCX1 KO mice exhibit significantly lower blood pressure and attenuated angiotensin II (Ang II)?salt?induced hypertension (measured by radio telemetry and intra?arterial catheterization). Isolated, pressurized mesenteric small resistance arteries from SM?NCX1 KO mice, compared to control arteries, were characterized by the following: (1) ~90% reduced NCX1 protein expression; (2) impaired functional responses to (i) acute NCX inhibition by SEA0400 or SN?6, (ii) NCX activation by low [Na+]o, and (iii) Na+ pump inhibition by ouabain; (3) attenuated myogenic reactivity; and (4) attenuated vasoconstrictor response to phenylephrine but not Ang II. These results provided direct evidence that arterial NCX1 normally mediates net Ca2+ influx that helps maintain basal vascular tone in small resistance arteries and blood pressure under physiological conditions. Importantly, NCX1 contributes to blood pressure elevation in Ang II?salt hypertension, possibly by regulating ??adrenergic receptor activation. PMID:25626872

  10. Conditional knockout of smooth muscle sodium calcium exchanger type-1 lowers blood pressure and attenuates Angiotensin II-salt hypertension.

    PubMed

    Wang, Youhua; Chen, Ling; Li, Meng; Cha, Helen; Iwamoto, Takahiro; Zhang, Jin

    2015-01-01

    The functions of smooth muscle sodium calcium exchanger (NCX) in the vasculature are controversial and poorly understood. To determine the possible roles of NCX in the vascular phenotype and function, we developed a novel mouse model (SM-NCX1 KO) in which the smooth muscle-specific NCX type-1 (NCX1) was conditionally knocked out using tamoxifen-inducible Cre-loxP recombination technique. SM-NCX1 KO mice exhibit significantly lower blood pressure and attenuated angiotensin II (Ang II)-salt-induced hypertension (measured by radio telemetry and intra-arterial catheterization). Isolated, pressurized mesenteric small resistance arteries from SM-NCX1 KO mice, compared to control arteries, were characterized by the following: (1) ~90% reduced NCX1 protein expression; (2) impaired functional responses to (i) acute NCX inhibition by SEA0400 or SN-6, (ii) NCX activation by low [Na(+)]o, and (iii) Na(+) pump inhibition by ouabain; (3) attenuated myogenic reactivity; and (4) attenuated vasoconstrictor response to phenylephrine but not Ang II. These results provided direct evidence that arterial NCX1 normally mediates net Ca(2+) influx that helps maintain basal vascular tone in small resistance arteries and blood pressure under physiological conditions. Importantly, NCX1 contributes to blood pressure elevation in Ang II-salt hypertension, possibly by regulating ?-adrenergic receptor activation. PMID:25626872

  11. Microstructural, textural, and sensory characteristics of probiotic yogurts fortified with sodium calcium caseinate or whey protein concentrate.

    PubMed

    Akal?n, A S; Unal, G; Dinkci, N; Hayaloglu, A A

    2012-07-01

    The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety. PMID:22720919

  12. Individual effects of sodium, potassium, calcium, and magnesium chloride salts on Lactobacillus pentosus and Saccharomyces cerevisiae growth.

    PubMed

    Bautista-Gallego, J; Arroyo-López, F N; Durán-Quintana, M C; Garrido-Fernandez, A

    2008-07-01

    A quantitative investigation on the individual effects of sodium (NaCl), potassium (KCl), calcium (CaCl2), and magnesium (MgCl2) chloride salts against Lactobacillus pentosus and Saccharomyces cerevisiae, two representative microorganisms of table olives and other fermented vegetables, was carried out. In order to assess their potential activities, both the kinetic growth parameters and dose-response profiles in synthetic media (deMan Rogosa Sharpe broth medium and yeast-malt-peptone-glucose broth medium, respectively) were obtained and analyzed. Microbial growth was monitored via optical density measurements as a function of contact time in the presence of progressive chloride salt concentrations. Relative maximum specific growth rate and lag-phase period were modeled as a function of the chloride salt concentrations. Moreover, for each salt and microorganism tested, the noninhibitory concentrations and the MICs were estimated and compared. All chloride salts exerted a significant antimicrobial effect on the growth cycle; particularly, CaCl2 showed a similar effect to NaCl, while KCl and MgCl2 were progressively less inhibitory. Microbial susceptibility and resistance were found to be nonlinearly dose related. PMID:18680941

  13. Binding of the water of primary hydration to the sodium and cesium salts of deoxyribonucleic acid and potassium hyaluronate

    NASA Astrophysics Data System (ADS)

    Whitson, K. B.; Lukan, A. M.; Marlowe, R. L.; Lee, S. A.; Anthony, L.; Rupprecht, A.

    1998-08-01

    Differential scanning calorimetry (DSC) has been used to evaluate the average enthalpy of desorption of the water of primary hydration bound to wet-spun films of potassium hyaluronate (KHA) and CsDNA. The enthalpies were measured to be 0.24+/-0.08 eV/H2O molecule for KHA and 0.32+/-0.10 eV/H2O molecule for CsDNA. A Kissinger analysis was used to extract the net activation energy (0.61+/-0.04 eV) for the desorption of this water from KHA by analyzing DSC data acquired at different heating rates. The average effective force constants at 295 K of this water bound to KHA (63+/-3 ?dyn/Å) and NaDNA (17+/-4 ?dyn/Å) are determined from Rayleigh scattering of Mossbauer radiation data [G. Albanese, A. Deriu, F. Cavatorta, and A. Rupprecht, Hyperfine Interact. 95, 97 (1995)] via a harmonic approximation.

  14. Effect of addition of silica- and amine functionalized silica-nanoparticles on the microstructure of calcium silicate hydrate (C-S-H) gel.

    PubMed

    Monasterio, Manuel; Gaitero, Juan J; Erkizia, Edurne; Guerrero Bustos, Ana M; Miccio, Luis A; Dolado, Jorge S; Cerveny, Silvina

    2015-07-15

    In this work we study the influence of adding nano-silica (SiO2, Nyasil™) and aminopropyl (-(CH2)3-NH2,) functionalized silica nanoparticles (Stoga) during the synthesis of calcium-silicate-hydrate (C-S-H gel). Characterization by solid state (29)Si NMR and ATR-FTIR spectroscopy showed that the addition of both particle types increases the average length of the silicate chains in C-S-H gel being this effect slightly more important in the case of Stoga particles. In addition, (13)C NMR and XPS confirmed that the aminopropyl chain remains in the final product cleaved to silicon atoms at the end of the silicate chain of C-S-H gel whereas XRD measurements showed that this result in an increment in the basal distance compared with ordinary CSH. In addition, the dynamics of water within the pores of C-S-H gel was analyzed by broadband dielectric spectroscopy. We observed that water confined in C-S-H formed with the addition of nanoparticles is faster than that in plain C-S-H which can be related to a different porous structure in these materials. PMID:25801139

  15. The hydrothermal decomposition of calcium monosulfoaluminate 14-hydrate to katoite hydrogarnet and ?-anhydrite: An in-situ synchrotron X-ray diffraction study

    NASA Astrophysics Data System (ADS)

    Meller, Nicola; Kyritsis, Konstantinos; Hall, Christopher

    2009-10-01

    We apply in-situ synchrotron X-ray diffraction to study the transformation of calcium monosulfoaluminate 14-hydrate Ca 4Al 2O 6(SO 4)·14H 2O [monosulfate-14] to hydrogarnet Ca 3Al 2(OH) 12 on the saturated water vapor pressure curve up to 250 °C. We use an aqueous slurry of synthetic ettringite Ca 6Al 2(SO 4) 3(OH) 12·26H 2O as the starting material; on heating, this decomposes at about 115 °C to form monosulfate-14 and bassanite CaSO 4·0.5H 2O. Above 170 °C monosulfate-14 diffraction peaks slowly diminish in intensity, perhaps as a result of loss of crystallinity and the formation of an X-ray amorphous meta-monosulfate. Hydrogarnet nucleates only at temperatures above 210 °C. Bassanite transforms to ?-anhydrite (insoluble anhydrite) at about 230 °C and this transformation is accompanied by a second burst of hydrogarnet growth. The transformation pathway is more complex than previously thought. The mapping of the transformation pathway shows the value of rapid in-situ time-resolved synchrotron diffraction.

  16. Computation of methodology-independent ionic solvation free energies from molecular simulations. II. The hydration free energy of the sodium cation.

    PubMed

    Kastenholz, Mika A; Hünenberger, Philippe H

    2006-06-14

    The raw ionic solvation free energies computed from atomistic (explicit-solvent) simulations are extremely sensitive to the boundary conditions (finite or periodic system, system shape, and size) and treatment of electrostatic interactions (Coulombic, lattice sum, or cutoff based) used during these simulations. In the present article, it is shown that correction terms can be derived for the effect of (A) an incorrect solvent polarization around the ion due to the use of an approximate (not strictly Coulombic) electrostatic scheme; (B) the finite size or artificial periodicity of the simulated system; (C) an improper summation scheme to evaluate the potential at the ion site and the possible presence of a liquid-vacuum interface in the simulated system. Taking the hydration free energy of the sodium cation as a test case, it is shown that the raw solvation free energies obtained using seven different types of boundary conditions and electrostatic schemes commonly used in explicit-solvent simulations (for a total of 72 simulations differing in the corresponding simulation parameters) can be corrected so as to obtain a consistent value for this quantity. PMID:16784292

  17. Calcium-Mediated Dual-Mode Regulation of Cardiac Sodium Channel Gating

    PubMed Central

    Biswas, Subrata; DiSilvestre, Deborah; Tian, Yanli; Halperin, Victoria L.; Tomaselli, Gordon F.

    2010-01-01

    Intracellular Ca2+ ([Ca2+]i) can trigger dual-mode regulation of the voltage gated cardiac sodium channel (NaV1.5). The channel components of the Ca2+ regulatory system are the calmodulin (CaM)-binding IQ motif and the Ca2+ sensing EF hand–like (EFL) motif in the carboxyl terminus of the channel. Mutations in either motif have been associated with arrhythmogenic changes in expressed NaV1.5 currents. Increases in [Ca2+]i shift the steady-state inactivation of NaV1.5 in the depolarizing direction and slow entry into inactivated states. Mutation of the EFL (NaV1.54X) shifts inactivation in the hyperpolarizing direction compared with the wild-type channel and eliminates the Ca2+ sensitivity of inactivation gating. Modulation of the steady-state availability of NaV1.5 by [Ca2+]i is more pronounced after the truncation of the carboxyl terminus proximal to the IQ motif (NaV1.5?1885), which retains the EFL. Mutating the EFL (NaV1.54X) unmasks CaM-mediated regulation of the kinetics and voltage dependence of inactivation. This latent CaM modulation of inactivation is eliminated by mutation of the IQ motif (NaV1.54X-IQ/AA). The LQT3 EFL mutant channel NaV1.5D1790G exhibits Ca2+ insensitivity and unmasking of CaM regulation of inactivation gating. The enhanced effect of CaM on NaV1.54X gating is associated with significantly greater fluorescence resonance energy transfer between enhanced cyan fluorescent protein–CaM and NaV1.54X channels than is observed with wild-type NaV1.5. Unlike other isoforms of the Na channel, the IQ-CaM interaction in the carboxyl terminus of NaV1.5 is latent under physiological conditions but may become manifest in the presence of disease causing mutations in the CT of NaV1.5 (particularly in the EFL), contributing to the production of potentially lethal ventricular arrhythmias. PMID:19265034

  18. Calcium-mediated dual-mode regulation of cardiac sodium channel gating.

    PubMed

    Biswas, Subrata; DiSilvestre, Deborah; Tian, Yanli; Halperin, Victoria L; Tomaselli, Gordon F

    2009-04-10

    Intracellular Ca(2+) ([Ca(2+)](i)) can trigger dual-mode regulation of the voltage gated cardiac sodium channel (Na(V)1.5). The channel components of the Ca(2+) regulatory system are the calmodulin (CaM)-binding IQ motif and the Ca(2+) sensing EF hand-like (EFL) motif in the carboxyl terminus of the channel. Mutations in either motif have been associated with arrhythmogenic changes in expressed Na(V)1.5 currents. Increases in [Ca(2+)](i) shift the steady-state inactivation of Na(V)1.5 in the depolarizing direction and slow entry into inactivated states. Mutation of the EFL (Na(V)1.5(4X)) shifts inactivation in the hyperpolarizing direction compared with the wild-type channel and eliminates the Ca(2+) sensitivity of inactivation gating. Modulation of the steady-state availability of Na(V)1.5 by [Ca(2+)](i) is more pronounced after the truncation of the carboxyl terminus proximal to the IQ motif (Na(V)1.5(Delta1885)), which retains the EFL. Mutating the EFL (Na(V)1.5(4X)) unmasks CaM-mediated regulation of the kinetics and voltage dependence of inactivation. This latent CaM modulation of inactivation is eliminated by mutation of the IQ motif (Na(V)1.5(4X-IQ/AA)). The LQT3 EFL mutant channel Na(V)1.5(D1790G) exhibits Ca(2+) insensitivity and unmasking of CaM regulation of inactivation gating. The enhanced effect of CaM on Na(V)1.5(4X) gating is associated with significantly greater fluorescence resonance energy transfer between enhanced cyan fluorescent protein-CaM and Na(V)1.5(4X) channels than is observed with wild-type Na(V)1.5. Unlike other isoforms of the Na channel, the IQ-CaM interaction in the carboxyl terminus of Na(V)1.5 is latent under physiological conditions but may become manifest in the presence of disease causing mutations in the CT of Na(V)1.5 (particularly in the EFL), contributing to the production of potentially lethal ventricular arrhythmias. PMID:19265034

  19. Treatment of the vertebral crush fracture syndrome with enteric-coated sodium fluoride tablets and calcium supplements.

    PubMed

    Nagant de Deuxchaisnes, C; Devogelaer, J P; Depresseux, G; Malghem, J; Maldague, B

    1990-03-01

    A cohort of 101 patients were treated with enteric-coated sodium fluoride tablets and calcium supplements. Vitamin D was also given in supra-physiologic doses in 70% of the cases. Lumbar bone mineral density (BMD), as measured by dual-photon absorptiometry, increased in a linear fashion up to four years, irrespective of the value of initial BMD and of the underlying condition, be it involutional osteoporosis (the vast majority), glucocorticoid osteoporosis, or even osteogenesis imperfecta. Estrogen replacement therapy (ERT) seemed to promote the fluoride-induced increase in lumbar BMD, as did the vitamin D supplements. Of these patients, 17% proved "resistant" to the therapy. There was no way of predicting who would be in this category. Compared with an age- and sex-matched control group, women showed significantly different behavior of their bone mass. In the control group, the losses were highly significant at the lumbar spine and at all three scanning sites of the forearm, as measured by single-photon absorptiometry. In contrast, the fluoride group had a significant gain of BMD at the lumbar spine and changes of BMC at the forearm were not significant. Fluoride thus preserved bone mass at the appendicular skeleton, while increasing it at the axial skeleton. When comparing the patients who received vitamin D supplements and those who did not, there was a significant difference in the appendicular skeleton. The distal forearm in the vitamin D-supplemented group tended to gain, whereas the midforearm lost significant bone mass. The trend was reversed in the group without vitamin D-supplementation, a more favorable pattern. Therefore, vitamin D supplements should not, as a rule, be provided to such patients. The biochemical hallmark of the fluoride-induced changes is a slight rise of the alkaline phosphatase within the normal range. Alkaline phosphatase levels that exceed the upper limit of normal signal a warning that too much fluoride and/or too little calcium supplements are being administered, or that a fluoride-related complication is impending or has occurred (e.g., a stress fracture). Osteosclerosis was achieved in 69% of the cases who had a radiological followup of at least four years (average period of appearance: 1.8 years). Stress fractures in the lower limbs occurred in 17 patients, almost exclusively in females, and appeared on average 2.2 years after initiation of therapy. In this group of stress fractures there was significant cortical bone loss at midforearm.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2187327

  20. Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, C{sub 4}A{sub 3}S{sup ¯}) in the presence of gypsum and varying amounts of calcium hydroxide

    SciTech Connect

    Hargis, Craig W. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA (United States)] [Department of Civil and Environmental Engineering, University of California, Berkeley, CA (United States); Kirchheim, Ana Paula [Department of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil)] [Department of Civil Engineering, Federal University of Rio Grande do Sul, Porto Alegre, RS (Brazil); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA (United States); Gartner, Ellis M. [Lafarge Centre de Recherche, St. Quentin Fallavier, Isere (France)] [Lafarge Centre de Recherche, St. Quentin Fallavier, Isere (France)

    2013-06-15

    Suspensions of synthetic ye'elimite (C{sub 4}A{sub 3}S{sup ¯}) in a saturated gypsum (CS{sup ¯}H{sub 2}) and calcium hydroxide (CH) solution were examined in-situ in a wet cell by soft X-ray transmission microscopy and ex-situ by scanning electron microscopy. The most voluminous hydration product observed was ettringite. Ettringite commonly displayed acicular, filiform, reticulated, and stellate crystal habits. Additionally, pastes with C{sub 4}A{sub 3}S{sup ¯}, 15% CS{sup ¯}H{sub 2}, and varying amounts of CH were prepared and examined with X-ray diffraction (XRD) and isothermal calorimetry. The XRD experiments showed that increasing CH content caused more solid solution (SO{sub 4}{sup 2?}/OH{sup ?}) AFm phases to form at early ages (< 1 d) and more monosulfate to form at later ages (> 1 d). Calorimetry indicated that the increased production of solid solution AFm was accompanied with an increase in the initial (< 30 min) rate of heat evolution, and increasing CH generally reduced the time till the second maximum rate of heat evolution due to the formation of ettringite and monosulfate.

  1. Insight into elastic behavior of calcium silicate hydrated oxide (C-S-H) under pressure and composition effect

    SciTech Connect

    Zaoui, Ali, E-mail: azaoui@polytech-lille.fr

    2012-02-15

    The present work relates to the study of structural and elastic properties of Tobermorite 11 A as a function of external pressure and composition in terms of calcium to silicon ratio. Basing on the lattice dynamics method, the main aim of this work is precisely to shed light, for the first time, on the high pressure structural phase transition in Tobermorite 11 A and the possible correlation with some elastic quantities. In order to check the transferability of the potentials used we have, additionally, performed a single calculation based on the density functional theory (DFT) for a pressure of 15 GPa in the case of Ca/Si = 1. The variation of the unit cell parameters with pressure indicates that Tobermorite 11 A undergoes a structural instability around 15 GPa along b-axis and around 20 GPa along a-axis which is confirmed from our calculations of X-Rays diffraction patterns at various pressure values. We have also observed the anisotropic character of the Tobermorite structure for both cases (Ca/Si = 1 and Ca/Si = 0.83). Our results show that around 20 GPa an important change appears in the elastic behaviour of Tobermorite. As pressure increases the calculated elastic quantities for Ca/Si = 1 became closer to those evaluated for Ca/Si = 0.83, which may stimulate further experimental and theoretical research on the matter.

  2. Genetic control and transgressive segregation of zinc, iron, potassium, phosphorus, calcium, and sodium accumulation in cowpea (Vigna unguiculata) seeds.

    PubMed

    Fernandes Santos, C A; Boiteux, L S

    2015-01-01

    Cowpea crop, through combining a range of essential minerals with high quality proteins, plays an important role in providing nutritional security to human population living in semi-arid regions. Studies on genetics of biofortification with essential minerals are still quite scarce, and the major objective of the present study was to provide genetic information on development of cowpea cultivars with high seed mineral contents. Genetic parameters heritability and minimum number of genes were estimated for seed accumulation of zinc (Zn), iron (Fe), calcium (Ca), phosphorus (P), potassium (K), and sodium (Na). Generation mean and variance analyses were conducted using contrasting parental lines, F1, F2, and backcross populations derived from IT97K-1042-3 x BRS Tapaihum and IT97K-1042-3 x Canapu crosses. High narrow-sense heritability (h2) values were found for accumulation of Fe (65-86%), P (74-77%), and K (77-88%), whereas moderate h(2) values were observed for accumulation of Ca (41-56%), Zn (51-83%), and Na (50-55%) in seeds. Significant additive genetic effects as well as parental mean effects were detected in both crosses for all minerals, whereas epistasis was important genetic component in Zn content. The minimum number of genes controlling the accumulation of minerals ranged from two (K) to 11 (P). Transgressive segregation was observed in F2 populations of both crosses for all minerals analyzed. The results suggest that, although under either oligogenic or polygenic control, the seed content of these six minerals in cowpea can be improved via standard breeding methods largely used for self-pollinated crops. PMID:25729958

  3. Molecular basis of calpain cleavage and inactivation of the sodium-calcium exchanger 1 in heart failure.

    PubMed

    Wanichawan, Pimthanya; Hafver, Tandekile Lubelwana; Hodne, Kjetil; Aronsen, Jan Magnus; Lunde, Ida Gjervold; Dalhus, Bjørn; Lunde, Marianne; Kvaløy, Heidi; Louch, William Edward; Tønnessen, Theis; Sjaastad, Ivar; Sejersted, Ole Mathias; Carlson, Cathrine Rein

    2014-12-01

    Cardiac sodium (Na(+))-calcium (Ca(2+)) exchanger 1 (NCX1) is central to the maintenance of normal Ca(2+) homeostasis and contraction. Studies indicate that the Ca(2+)-activated protease calpain cleaves NCX1. We hypothesized that calpain is an important regulator of NCX1 in response to pressure overload and aimed to identify molecular mechanisms and functional consequences of calpain binding and cleavage of NCX1 in the heart. NCX1 full-length protein and a 75-kDa NCX1 fragment along with calpain were up-regulated in aortic stenosis patients and rats with heart failure. Patients with coronary artery disease and sham-operated rats were used as controls. Calpain co-localized, co-fractionated, and co-immunoprecipitated with NCX1 in rat cardiomyocytes and left ventricle lysate. Immunoprecipitations, pull-down experiments, and extensive use of peptide arrays indicated that calpain domain III anchored to the first Ca(2+) binding domain in NCX1, whereas the calpain catalytic region bound to the catenin-like domain in NCX1. The use of bioinformatics, mutational analyses, a substrate competitor peptide, and a specific NCX1-Met(369) antibody identified a novel calpain cleavage site at Met(369). Engineering NCX1-Met(369) into a tobacco etch virus protease cleavage site revealed that specific cleavage at Met(369) inhibited NCX1 activity (both forward and reverse mode). Finally, a short peptide fragment containing the NCX1-Met(369) cleavage site was modeled into the narrow active cleft of human calpain. Inhibition of NCX1 activity, such as we have observed here following calpain-induced NCX1 cleavage, might be beneficial in pathophysiological conditions where increased NCX1 activity contributes to cardiac dysfunction. PMID:25336645

  4. Hydrate detection

    SciTech Connect

    Dillon, W.P.; Ahlbrandt, T.S.

    1992-06-01

    Project objectives were: (1) to create methods of analyzing gas hydrates in natural sea-floor sediments, using available data, (2) to make estimates of the amount of gas hydrates in marine sediments, (3) to map the distribution of hydrates, (4) to relate concentrations of gas hydrates to natural processes and infer the factors that control hydrate concentration or that result in loss of hydrate from the sea floor. (VC)

  5. Hydrate detection

    SciTech Connect

    Dillon, W.P.; Ahlbrandt, T.S.

    1992-01-01

    Project objectives were: (1) to create methods of analyzing gas hydrates in natural sea-floor sediments, using available data, (2) to make estimates of the amount of gas hydrates in marine sediments, (3) to map the distribution of hydrates, (4) to relate concentrations of gas hydrates to natural processes and infer the factors that control hydrate concentration or that result in loss of hydrate from the sea floor. (VC)

  6. A Raman spectroscopic study of glasses along the joins silica-calcium aluminate, silica-sodium aluminate, and silica-potassium aluminate

    NASA Astrophysics Data System (ADS)

    McMillan, Paul; Piriou, Bernard; Navrotsky, Alexandra

    1982-11-01

    Aluminosilicate glasses with compositions along the joins silica-calcium aluminate, silica sodium aluminate and silica-potassium aluminate have been prepared by conventional and solar melting techniques and studied by Raman spectroscopy. The Raman spectra of crystalline calcium aluminate, anorthite and silica polymorphs are discussed in relation to their crystal structures, and compared with the spectra of the corresponding glasses. The glass and crystal spectra are generally comparable, suggesting similar vibrational structures. These crystals have structures based on tetrahedral aluminosilicate frameworks, and a similar molecular structure is suggested for the glasses, although it is noted that the Raman spectra do not directly characterize the aluminate polyhedra. Within the three glass series, our interpretation of the unresolved high-frequency bands shows the appearance of discrete bands near 1120, 1000, 930 and 890 cm -1 as the silica content is decreased. This is compared with the behaviour of high-frequency bands in simple silicate systems, and used to suggest that the four bands in the aluminosilicate systems are due to stretching vibrations of silicate tetrahedra bound to one, two, three and four aluminium atoms. The spectra of calcium, sodium, potassium and lithium aluminosilicate glasses with similar silica contents are compared, and interpreted by the above model. This is used to construct a simple model for the effect of metal cation on aluminosilicate molecular groups in the glass structure, consistent with the results of calorimetric studies on similar systems.

  7. Effect of pulverised-fuel ash on the C\\/S molar ratio and alkali content of calcium silicate hydrates in cement

    Microsoft Academic Search

    P RAYMENT

    1982-01-01

    It has been found that for a cement that has been hydrated for 8 days, pulverized-fuel ash (pfa) caused the C\\/S ratio of the hydrates around the grains to be lowered from 1.71 to 1.55. More potassium was found in the lower C\\/S ratio hydrates. It is not clear whether the resulting reduction in available alkali is sufficient to explain

  8. Hydration-Coupled Dynamics in Proteins Studied by Neutron Scattering and NMR: The Case of the Typical EF-Hand Calcium-Binding Parvalbumin

    Microsoft Academic Search

    Jean-Marc Zanotti; Marie-Claire Bellissent-Funel; Joseph Parello

    1999-01-01

    The influence of hydration on the internal dynamics of a typical EF-hand calciprotein, parvalbumin, was investigated by incoherent quasi-elastic neutron scattering (IQNS) and solid-state 13C-NMR spectroscopy using the powdered protein at different hydration levels. Both approaches establish an increase in protein dynamics upon progressive hydration above a threshold that only corresponds to partial coverage of the protein surface by the

  9. ELECTROPHORESIS OF BACTERIA AS INFLUENCED BY HYDROGEN ION CONCENTRATION AND THE PRESENCE OF SODIUM AND CALCIUM SALTS

    PubMed Central

    Winslow, C.-E. A.; Falk, I. S.; Caulfield, M. F.

    1923-01-01

    1. We have confirmed the results of earlier workers particularly of Northrop and De Kruif in regard to the following points: (a) the general tendency of the bacterial cell when suspended in distilled water near the zone of neutrality to move toward the anode of an electrical field; (b) the fact that the migration of bacterial cells in the electrical field is a function of the reaction of the menstruum. The curve obtained by plotting velocity of migration against pH passes through an isoelectric point at about pH 3.0, at greater acidity the direction of migration becomes reversed (toward the cathode) and in still more acid solution (pH = 1.0) again disappears; while at reactions less acid than pH 3.0 the velocity is toward the anode and increases with increasing alkalinity; (c) the fact that neutral salts depress the velocity of migration, calcium salts being much more effective than sodium salts of the same concentration. 2. We further find: (a) that on the extreme alkaline side of the curve of velocity of migration plotted against pH a maximum value is reached at about pH 10 with a fall at about pH 12.0 which in many experiments reaches an isopotential point; (b) that the depressing effect of salts is accompanied by a general shifting of the curve of migration velocity so that a maximum velocity (of course absolutely less than that manifest in the absence of salts) appears at about pH 7.0 and an abolition of velocity at pH 9.0 to 10.0; (c) that an apparent "antagonistic" effect is indicated between CaCl2 and NaCl, the presence of a certain concentration of the latter salt diminishing to a slight but definite degree the depressing effect produced by the former; (d) that heat-killed bacterial cells exhibit essentially the same curve of migration velocity as that of the living cells; (e) that bacterial spores exhibit the same general curve of migration velocity as vegetative cells, although the actual velocity is apparently slightly less. 3. All of the observed phenomena appear to be in accord with the assumption that marked differences in dielectric constants did not appear under the conditions studied and if this assumption be granted the results are in accord with the fundamental postulates of the Donnan equilibrium as applied to the explanation of the origin of potential difference between a bacterial cell and its enveloping menstruum. It is possible but not at all certain that the phenomenon of antagonism may require the introduction of additional assumptions for its explanation. Professor Donnan and other investigators have clearly understood the importance of applying the concept of membrane equilibria in the elucidation of physiological phenomena. Our findings add to the numerous vindications favoring this view and emphasize the importance of further study of membrane equilibria in bacterial suspensions. We have pointed out that certain potential differences between bacteria and their menstrua are apparently associated with some of the phenomena of viability. Viability and potential differences may, however, under certain conditions vary quite independently as evidenced by the fact that normal rates of migration are demonstrable after the cells have been killed by heat. Thus, considerable caution must be exercised in relating the existence of these charges to the metabolism of the cell. PMID:19872061

  10. Hydration-coupled dynamics in proteins studied by neutron scattering and NMR: the case of the typical EF-hand calcium-binding parvalbumin.

    PubMed Central

    Zanotti, J M; Bellissent-Funel, M C; Parello, J

    1999-01-01

    The influence of hydration on the internal dynamics of a typical EF-hand calciprotein, parvalbumin, was investigated by incoherent quasi-elastic neutron scattering (IQNS) and solid-state 13C-NMR spectroscopy using the powdered protein at different hydration levels. Both approaches establish an increase in protein dynamics upon progressive hydration above a threshold that only corresponds to partial coverage of the protein surface by the water molecules. Selective motions are apparent by NMR in the 10-ns time scale at the level of the polar lysyl side chains (externally located), as well as of more internally located side chains (from Ala and Ile), whereas IQNS monitors diffusive motions of hydrogen atoms in the protein at time scales up to 20 ps. Hydration-induced dynamics at the level of the abundant lysyl residues mainly involve the ammonium extremity of the side chain, as shown by NMR. The combined results suggest that peripheral water-protein interactions influence the protein dynamics in a global manner. There is a progressive induction of mobility at increasing hydration from the periphery toward the protein interior. This study gives a microscopic view of the structural and dynamic events following the hydration of a globular protein. PMID:10233057

  11. ORIGINAL ARTICLE Carbonation and hydration behavior of EAF and BOF steel

    E-print Network

    after a combination of carbonation and hydration. Higher calcium silicate content and longer carbonation of calcium carbonates inter- mingled with calcium silicate hydrates, forming a particle reinforced composite material. It was the calcium silicate content in raw slag, rather than the CaO content, that determined

  12. Cement & Concrete Science Conference: Leeds, 2009 Hydration of alite containing aluminium

    E-print Network

    Paris-Sud XI, Université de

    in cement is tricalcium silicate which leads during its hydration to the nucleation and growth of calcium of calcium silicate and calcium aluminate phases [1]. The most important one in terms by weight,3] leading to the heterogeneous precipitation of a calcium silicate hydrate referred to C-S-H ((CaO)x-SiO2-(H

  13. The effect of casein phosphopeptide-amorphous calcium phosphate paste and sodium fluoride mouthwash on the prevention of dentine erosion: An in vitro study

    PubMed Central

    Moezizadeh, Maryam; Alimi, Azar

    2014-01-01

    Aim: The purpose was to compare the effect of 0.2% sodium fluoride mouthwash and casein phosphopeptide-amorphous calcium phosphate paste on prevention of dentin erosion. Materials and Methods: Buccal surfaces of 36 sound premolar teeth were ground flat and polished with abrasive discs. Half the polished surfaces were covered with tape to maintain a reference surface. Samples were randomly allocated into three groups. Group A was pretreated with tooth mousse (TM) 4 times a day for 5 days. Group B was pretreated with 0.2% sodium fluoride mouthwash 4 times a day for 5 days. Group C was considered as the control group with no pretreatment. In the next step, the samples were exposed to Coca-Cola 4 times a day for 3 days. After each erosive cycle, the samples were rinsed with deionized water and stored in artificial saliva. The surface loss was determined using profilometry. Results: The erosion in both Groups A and B was less than the control group. The surface loss in mouthwash group was significantly lower than in the control group. Erosion in TM group was more than the mouthwash group and less than the control group. Conclusion: Sodium fluoride mouthwash is more effective for prevention of dentin erosion. PMID:24944448

  14. Sodium-, chloride-, and mibefradil-sensitive calcium channels in intestinal pacing in wild-type and W/WV mice.

    PubMed

    Boddy, Geoffrey; Willis, A; Galante, G; Daniel, E E

    2006-06-01

    Pacing of intestinal smooth muscle is driven by a network of cells found in the myenteric plexus called the interstitial cells of Cajal (ICC-MP), which produce a rhythmic pacemaker current. Using intact segments of circular (CM) and longitudinal (LM) muscle from wild-type and W/WV mice, we found that sodium-, chloride-, and mibefradil-sensitive ion channel currents are required for normal pacing to occur. Application of 30 micromol/L and 300 micromol/L lidocaine, 1 mmol/L 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), 50 nmol/L and 500 nmol/L mibefradil, or low sodium Krebs significantly reduced pacing frequency in LM and CM. However, simultaneously applying DIDS and lidocaine or low sodium Krebs solution did not completely block pacing nor did it have an additive effect. Lidocaine and low sodium Krebs solution also abolished the gradient of pacing frequencies (higher proximally) found throughout the intestine, resulting in a uniform contraction frequency of 30-40/min. In W/WV mice, which lack ICC-MP, application of DIDS and lidocaine had no effect on the robust pacing in LM segments. In conclusion we found that sodium-, chloride-, and mibefradil-sensitive channel activities were required for normal pacing and to maintain the pacing gradient found throughout the intestines in wild-type but not W/WV mice. PMID:16900243

  15. A realistic molecular model of cement hydrates

    E-print Network

    Ulm, Franz-Josef

    Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these ...

  16. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Sodium carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N -lauroyl sarcosinate. Artificial sweeteners that are...

  17. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Sodium carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N -lauroyl sarcosinate. Artificial sweeteners that are...

  18. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Sodium carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N -lauroyl sarcosinate. Artificial sweeteners that are...

  19. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Sodium carboxymethylcellulose. Tetrasodium pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N -lauroyl sarcosinate. Artificial sweeteners that are...

  20. Small-scale pilot evaluation of calcium- and sodium-based sorbents for dry SO/sub 2/ removal. Report for January-December 1986

    SciTech Connect

    Jorgensen, C.; Chang, J.C.S.; Brna, T.G.; Sedman, C.B.

    1987-03-01

    The paper discusses a 100 cu m/h pilot facility (consisting of a spray dryer, a sorbent injection system, a duct section, and a pulse-jet baghouse or cyclone separator) used for testing the reaction at low temperature between various calcium- and sodium-based sorbents and SO/sub 2/ in the concentration range of 1000-2500 ppm. The sorbents tested were based on earlier-reported sand-bed reactor (0.3 cu m/h) tests. The performance of these sorbents is compared in terms of SO/sub 2/ removal and stoichiometry with that obtained using conventional slaked lime in spray drying or dry injection under similar conditions.

  1. Pilot-test of the calcium sodium phosphate (CNP) process for the stabilization/solidification of various mercury-contaminated wastes.

    PubMed

    Cho, Jae Han; Eom, Yujin; Lee, Tai Gyu

    2014-12-01

    A pilot-scale calcium sodium phosphate (CNP) plant was designed and manufactured to examine the performance of recently developed stabilization/solidification (S/S) technology. Hg-contaminated wastes samples generated via various industrial processes in Korea, including municipal, industrial, and medical waste incineration, wastewater treatment, and lime production, were collected and treated using the pilot-scale CNP plant. S/S samples were fabricated according to various operating conditions, including waste type, the dose of the stabilization reagent (Na2S), and the waste loading ratio. Although the performances (Hg leaching value and compressive strength) were reduced as the waste loading ratio increased, most of the S/S samples exhibited Hg leaching values that were below the universal treatment standard limit of 25 ?g L(-1) and compressive strengths that exceeded the criterion of 3.45 MPa. PMID:25169648

  2. Terahertz spectroscopy of concrete for evaluating the critical hydration level

    NASA Astrophysics Data System (ADS)

    Dash, Jyotirmayee; Ray, Shaumik; Nallappan, Kathirvel; Sasmal, Saptarshi; Pesala, Bala

    2014-03-01

    Concrete, a mixture of cement, coarse aggregate, sand and filler material (if any), is widely used in the construction industry. Cement, mainly composed of Tricalcium Silicate (C3S) and Dicalcium Silicate (C2S) reacts readily with water, a process known as hydration. The hydration process forms a solid material known as hardened cement paste which is mainly composed of Calcium Silicate Hydrate (C-S-H), Calcium Hydroxide and Calcium Carbonate. To quantify the critical hydration level, an accurate and fast technique is highly desired. However, in conventional XRD technique, the peaks of the constituents of anhydrated and hydrated cement cannot be resolved properly, where as Mid-infrared (MIR) spectroscopy has low penetration depth and hence cannot be used to determine the hydration level of thicker concrete samples easily. Further, MIR spectroscopy cannot be used to effectively track the formation of Calcium Hydroxide, a key by-product during the hydration process. This paper describes a promising approach to quantify the hydration dynamics of cement using Terahertz (THz) spectroscopy. This technique has been employed to track the time dependent reaction mechanism of the key constituents of cement that react with water and form the products in the hydrated cement, viz., C-S-H, Calcium Hydroxide and Calcium Carbonate. This study helps in providing an improved understanding on the hydration kinetics of cement and also to optimise the physio-mechanical characteristics of concrete.

  3. Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite.

    PubMed

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers <5 microm were not classified as to their carcinogenicity to humans. Likewise, Clinoptilolite, Phillipsite, Mordenite, Nonfibrous Japanese Zeolite, and synthetic Zeolites were not classified as to their carcinogenicity to humans. These ingredients are not significantly toxic in oral acute or short-term oral or parenteral toxicity studies in animals. Inhalation toxicity, however, is readily demonstrated in animals. Particle size, fibrogenicity, concentration, and mineral composition had the greatest effect on toxicity. Larger particle size and longer and wider fibers cause more adverse effects. Magnesium Aluminum Silicate was a weak primary skin irritant in rabbits and had no cumulative skin irritation in guinea pigs. No gross effects were reported in any of these studies. Sodium Magnesium Silicate had no primary skin irritation in rabbits and had no cumulative skin irritation in guinea pigs. Hectorite was nonirritating to the skin of rabbits in a Draize primary skin irritation study. Magnesium Aluminum Silicate and Sodium Magnesium Silicate caused minimal eye irritation in a Draize eye irritation test. Bentonite caused severe iritis after injection into the anterior chamber of the eyes of rabbits and when injected intralamellarly, widespread corneal infiltrates and retrocorneal membranes were recorded. In a primary eye irritation study in rabbits, Hectorite was moderately irritating without washing and practically nonirritating to the eye with a washout. Rats tolerated a single dose of Zeolite A without any adverse reaction in the eye. Calcium Silicate had no discernible effect on nidation or on maternal or fetal survival in rabbits. Magnesium Aluminum Silicate had neither a teratogenic nor adverse effects on the mouse fetus. Female rats receiving a 20% Kaolin diet exhibited maternal anemia but no significant reduction in birth weight of the pups was recorded. Type A Zeolite produced no adverse effects on the dam, embryo, or fetus in either rats or rabbits at any dose level. Clinoptilolite had no effect on female rat reproductive performance. These ingredients were not genotoxic in the Ames bacterial test system. In primary hepatocyte cultures, the addition of Attapulgite had no significant unscheduled DNA synthesis. Attapulgite did cause significant increases in unscheduled DNA synthesis in rat pleural mesothelial cells, but no significant increase in sister chromosome exchanges were seen. Zeolite particles (<10 microm) produced statistically significant increase in the percentage of aberrant metaphases in human peripheral blood lymphocytes and cells collected by peritoneal lavage from exposed mice. Topical application of Magnesium Aluminum Silicate to human skin daily for 1 week produced no adverse effects. Occupational exposure to mineral dusts has been studied extensively. Fibrosis and pneumoconiosis have been documented in workers involved in the mining and processing of Aluminum Silicate, Calcium Silicate, Zirconium Silicate, Fuller's Earth, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite. The Cosmetic Ingre

  4. Formation of ettringite, Ca 6Al 2(SO 4) 3(OH) 12·26H 2O, AFt, and monosulfate, Ca 4Al 2O 6(SO 4)·14H 2O, AFm-14, in hydrothermal hydration of Portland cement and of calcium aluminum oxide—calcium sulfate dihydrate mixtures studied by in situ synchrotron X-ray powder diffraction

    NASA Astrophysics Data System (ADS)

    Christensen, Axel Nørlund; Jensen, Torben R.; Hanson, Jonathan C.

    2004-06-01

    In the hydration of calcium aluminum oxide-gypsum mixtures, i.e., Ca 3Al 2O 6, Ca 12Al 14O 33 and CaSO 4·2H 2O, the reaction products can be ettringite, Ca 6Al 2(SO 4) 3(OH) 12·26H 2O, monosulfate, Ca 4Al 2O 6(SO 4)·14H 2O, or the calcium aluminum oxide hydrate, Ca 4Al 2O 7·19H 2O. Ettringite is formed if sufficient CaSO 4·2H 2O is present in the mixture. Ettringite is converted to monosulfate when all CaSO 4·2H 2O is consumed in the synthesis of ettringite. The reactions were investigated in the temperature range 25-170°C using in situ synchrotron X-ray powder diffraction. This technique allows the study of very fast chemical reactions that are observed here under hydrothermal conditions. A new experimental approach was developed to perform in situ mixing of the reactants during X-ray data collection.

  5. Surfactant effects on hydrate formation in an unstirred gas\\/liquid system: An experimental study using methane and sodium alkyl sulfates

    Microsoft Academic Search

    Kazunori Okutani; Yui Kuwabara; Yasuhiko H. Mori

    2008-01-01

    This paper reports an experimental study on the effects of surfactant additives on the formation of a clathrate hydrate in a quiescent methane\\/liquid-water system, which was initially composed of a 300-cm3 aqueous phase and an ?640-cm3 methane-gas phase, then successively provided with methane such that the system pressure was held constant. The surfactants used in the present study were three

  6. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride solution and also by reacting calcium hydroxide with sodium carbonate. (b) The ingredient meets the specifications of the...

  7. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride solution and also by reacting calcium hydroxide with sodium carbonate. (b) The...

  8. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride solution and also by reacting calcium hydroxide with sodium carbonate. (b) The ingredient...

  9. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride solution and also by reacting calcium hydroxide with sodium carbonate. (b) The...

  10. 21 CFR 184.1763 - Sodium hydroxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium hydroxide is prepared commercially by the electrolysis of sodium chloride solution and also by reacting calcium hydroxide with sodium carbonate. (b) The...

  11. Separation of sodium-22 from irradiated targets

    DOEpatents

    Taylor, Wayne A. (Los Alamos, NM); Jamriska, David (Los Alamos, NM)

    1996-01-01

    A process for selective separation of sodium-22 from an irradiated target including dissolving an irradiated target to form a first solution, contacting the first solution with hydrated antimony pentoxide to selectively separate sodium-22 from the first solution, separating the hydrated antimony pentoxide including the separated sodium-22 from the first solution, dissolving the hydrated antimony pentoxide including the separated sodium-22 in a mineral acid to form a second solution, and, separating the antimony from the sodium-22 in the second solution.

  12. Relationships Between Calcium Silicates and Clay Minerals

    Microsoft Academic Search

    H. F. W. Taylor; J. W. HowlsoN

    1956-01-01

    The crystal-chemical basis of the relationship between hydrated calcium silicate and clay minerals is discussed, and a review is given of recent work on the tobermorite minerals, the group of hydrated calcium silicates which most nearly resembles the clay minerals. New data are presented for the specific gravities, refractive indices, basal spacings, and dehydration isobars of synthetic tobermorite minerals, and

  13. Solvent effects on squid sodium channels are attributable to movements of a flexible protein structure in gating currents and to hydration in a pore

    PubMed Central

    Kukita, Fumio

    2000-01-01

    Solvent effects on the time course of gating and sodium currents were analysed in squid sodium channels using four non-electrolytes of different size, glycerol, erythritol, glucose and sucrose, to separate effects of viscosity from those of osmolarity and to obtain viscosity and osmolarity parameters that were independent of molecular size. The gating and sodium currents were reversibly slowed in a voltage-independent manner as the non-electrolyte concentration increased. Solvent effects were analysed using a model in which the percentage change in time constant was expressed by an equation involving the viscosity parameter ? and the osmolarity parameter ?: t/t0 =?((?/?0) – 1 + 100??1)exp(???), where ?/?0 is solution viscosity and ?? is increase in osmolarity. Since the solution viscosity was found experimentally to be a function of the solution osmolarity, solvent effects are described by an equation with one independent variable ?/?0 or ??. Voltage sensor movement, reflected in gating currents, was primarily sensitive to viscosity, as its decay time constant was a function of ?/?0, with only a minor sensitivity to osmolarity (? was 2–3 water molecules). For sodium currents, ? was equal to that of gating currents but ? was 2–3 times greater, suggesting that the final channel opening was primarily sensitive to osmolarity (?? was 5 water molecules). The relative ineffectiveness of the largest non-electrolyte, sucrose, suggested that this osmolarity-sensitive step in channel opening occurred in the narrow pore region. Sodium channel inactivation was primarily sensitive to osmolarity (?? was 8–12 water molecules). The observed viscosity dependence of the sodium current activation and inactivation processes was attributable to the viscosity-dependent process accompanying the gating current. This model explains why non-electrolytes slow sodium currents while electrolytes do not. Viscosity effects on gating currents can be explained by a process in which non-electrolytes interact with the flexible hydrophilic parts of sodium channel proteins, but osmolarity effects on the final step need to be explained by a local interaction of several water molecules with fluctuating protein segments in the pore. PMID:10713962

  14. A five way crossover human volunteer study to compare the pharmacokinetics of paracetamol following oral administration of two commercially available paracetamol tablets and three development tablets containing paracetamol in combination with sodium bicarbonate or calcium carbonate.

    PubMed

    Grattan, T; Hickman, R; Darby-Dowman, A; Hayward, M; Boyce, M; Warrington, S

    2000-05-01

    This report concerns a single dose randomized five way crossover study to compare the pharmacokinetics of paracetamol from two commercially available paracetamol (500 mg) tablets and three different development paracetamol (500 mg) tablet formulations containing either sodium bicarbonate (400 mg), sodium bicarbonate (630 mg) or calcium carbonate (375 mg). The results demonstrated that addition of sodium bicarbonate (630 mg) to paracetamol tablets, increased the rate of absorption of paracetamol relative to conventional paracetamol tablets and soluble paracetamol tablets. Addition of sodium bicarbonate (400 mg) to paracetamol tablets increased the absorption rate of paracetamol relative to conventional paracetamol tablets, but there was no difference in the rate of absorption compared to soluble paracetamol tablets. Inclusion of calcium carbonate (375 mg) to paracetamol tablets had no effect on absorption kinetics compared to the conventional paracetamol tablet. The faster absorption observed for the sodium bicarbonate formulations may be as a result of an increase in gastric emptying rate leading to faster transport of paracetamol to the small intestine where absorption takes place. PMID:10799813

  15. How does calcium-dependent intracellular regulation of voltage-dependent sodium current increase the sensitivity to the oxadiazine insecticide indoxacarb metabolite decarbomethoxylated JW062 (DCJW) in insect pacemaker neurons?

    PubMed

    Lavialle-Defaix, Céline; Moignot, Bénédicte; Legros, Christian; Lapied, Bruno

    2010-04-01

    Decarbomethoxylated JW062 (DCJW), the active component of the oxadiazine insecticide (S)-methyl 7-chloro-2,5-dihydro-2-[[(methoxycarbonyl)[4-(trifluoromethoxy)phenyl] amino]carbonyl] indeno[1,2-e][1,3,4]oxadiazine-4a(3H)-carboxylate (DPX-JW062) (indoxacarb), was tested on 2 inward voltage-dependent sodium currents (named INa1 and INa2) expressed in short-term cultured dorsal unpaired median neurons of the cockroach Periplaneta americana. Under whole-cell voltage-clamp conditions, application of DCJW resulted in a biphasic dose-dependent inhibition of the global sodium current amplitude illustrating the differing sensitivity of sodium channels to DCJW. INa2 was less sensitive to DCJW [half-maximal inhibitory concentration (IC(50)) = 1.6 microM] compared with INa1 (IC(50) = 1.7 nM). Although a previous study demonstrated that INa1 was regulated by the cAMP/protein kinase A cascade, we showed that INa2 was mainly regulated in an opposite way by the activation of calcium-calmodulin-dependent protein phosphatase 2B (PP2B) and calcium-calmodulin-dependent protein kinase II (CaM-kinase II). Furthermore, we demonstrated that activation of CaM-kinase II by intracellular calcium via the calcium-calmodulin complex affected the sensitivity of INa2 channels to DCJW. By increasing the intracellular calcium concentration and/or using 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) (a calcium chelator), N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride (W7) (a calmodulin inhibitor), cyclosporine A (a PP2B inhibitor), and 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62) (a CaM-kinase II inhibitor), we revealed that activation of CaM-kinase II was involved in the modulation of the voltage dependence of steady-state inactivation and that the CaM-kinase II pathway activated by elevation of the intracellular calcium concentration might render INa2 channels approximately 3000-fold more sensitive to DCJW. These results indicated that manipulating specific intracellular signaling pathways involved in the regulation of sodium channels might have fundamental consequences for the sensitivity of insects to insecticides. This finding reveals an exciting research area that could lead to improvement in the efficiency of insecticides. PMID:20056780

  16. Tunable color temperature solid state white light source using flux grown phosphor crystals of Eu3+, Dy3+ and Tb3+ activated calcium sodium molybdenum oxide

    NASA Astrophysics Data System (ADS)

    Khanna, A.; Dutta, P. S.

    2014-11-01

    Solid state light sources with dynamically tunable color temperature in the range of 3000-6000 K with chromaticity coordinates lying on the Planckian black body curve has been designed using mixtures of narrow emissions at 615 nm, 575 nm and 550 nm. These respective emissions lines were generated by individual phosphor crystals of trivalent rare earth (RE3+) species, europium (Eu3+), dysprosium (Dy3+) and terbium (Tb3+) activated calcium sodium molybdenum oxide (Ca1-2xNaxMoO4:RE3+x), when excited by near-ultra-violet (NUV) light emitting diode (LED) with emission wavelength of 380 nm. Highly luminescent crystals of these compounds have been grown from molten solutions (flux) of molybdenum (VI) oxide. The flux grown crystals exhibit emission intensity 2-4 times more than phosphor powders of the same compounds synthesized by traditional solid-state reactions. An optimum flux to solute ratio of 2.5 and solute dissolution temperature of 1100 °C resulted in the largest size crystals.

  17. Influence of finely ground limestone on cement hydration

    Microsoft Academic Search

    Jean Péra; Sophie Husson; Bernard Guilhot

    1999-01-01

    Some work has been carried out on the effect of calcium carbonate on cement paste, but there is no general agreement on the relative effects of different amounts of calcium carbonate on cement paste properties. The objective of the present work is to assess the effect of various amounts of calcium carbonate on the hydration of tricalcium silicate in order

  18. Emissions of alkaline elements calcium, magnesium, potassium, and sodium from open sources in the contiguous United States

    SciTech Connect

    Gillette, D.A. (National Oceanic and Atmospheric Administration, Boulder, CO (United States)); Stensland, G.J.; Williams, A.L.; Barnard, W.; Gatz, D. (Illinois State Water Survey, Champaign, IL (United States)); Sinclair, P.C. (Colorado State Univ., Fort Collins (United States)); Johnson, T.C. (Univ. of Colorado, Boulder (United States))

    1992-12-01

    Models of dust emissions by wind erosion (including winds associated with regional activity as well as dust devils) and vehicular disturbances of unpaved roads were developed, calibrated, and used to estimate alkaline dust emissions from elemental soil and road composition data. Emissions from tillage of soils were estimated form the work of previous researchers. The area of maximum dust production by all of those sources is the area of the old Dust Bowl' of the 1930s (the panhandles of Texas and Oklahoma, eastern New Mexico and Colorado, and western Kansas). The areas of maximum alkaline dust production are the arid southwest, the Dust Bowl,' and the midwestern-mideastern states from Iowa to Pennsylvania. Our calculations show that calcium is the dominant alkaline element produced by open sources' (sources too great in extent to be controlled by enclosure or ducting). Although the largest dust mass source is wind erosion (by winds associated with regional activity and convective activity), the largest producer of the alkaline component is road dust because the abundance of alkaline materials in road coverings (which include crushed limestone) is significantly higher than for soils. Comparing the above estimated sources of alkaline material with inventories of SO[sub 2] and NO[sub x] emissions by previous investigators gives the rough approximation that alkaline emission rates are of the order of the SO[sub 2] + NO[sub x] emissions in the western United States and that they are much smaller than SO[sub 2] + NO[sub x] in the eastern United States. This approximation is substantiated by data on Ca/(SO[sub 4] + NO[sub 3]) for wet deposition for National Atmospheric Deposition Program sites. 53 refs., 9 figs., 2 tabs.

  19. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721.2076 Protection...acetate, calcium magnesium potassium sodium salt. (a) Chemical substance and significant...acetate, calcium magnesium potassium sodium salt (PMN P-00-7; CAS...

  20. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721.2076 Protection...acetate, calcium magnesium potassium sodium salt. (a) Chemical substance and significant...acetate, calcium magnesium potassium sodium salt (PMN P-00-7; CAS...

  1. ESP (electrostatic precipitator) tests at Toronto: Test results: Part 3. [Hydrate Addition at Low Temperature for the removal of SOâ

    Microsoft Academic Search

    J. Gooch; R. Beittel; J. DuBard; G. Jr. Marchant

    1988-01-01

    ''Hydrate Addition at Low Temperature'' or HALT is a dry calcium-based hydrate injection process for the removal of SOâ from flue gases off a sulfur bearing fuel. In this process the hydrate is pneumatically conveyed and injected into the flue gas stream as a dry particulate. The flue gas is cooled downstream of the hydrate injection location by spraying the

  2. Effects of a Fusarium toxin-contaminated maize treated with sodium metabisulphite, methylamine and calcium hydroxide in diets for female piglets.

    PubMed

    Rempe, Inga; Brezina, Ulrike; Kersten, Susanne; Dänicke, Sven

    2013-08-01

    Deoxynivalenol (DON) and zearalenone (ZEN) contaminated maize was hydrothermally treated in the presence of sodium metabisulphite (SBS), methylamine and calcium hydroxide (Ca(OH)2) and included into diets for female piglets to evaluate effects on performance, organ weights, development of hyperestrogenism, serum biochemical parameters, stimulation of peripheral blood mononuclear cells and toxin residues in serum. For this purpose, both uncontaminated maize (CON) and Fusarium toxin-contaminated maize (FUS) were included into diets either untreated (-) or treated (+) according to a 2 by 2-factorial design. One-hundred female weaned piglets were assigned to one of the four treatment groups (n = 25) CON-, CON+, FUS- and FUS+ with DON/ZEN concentrations of 0.43/0.03, 0.04/0.0, 3.67/0.32 and 0.36/0.08 mg per kg diet, respectively. After a feeding period of 27 days, 20 piglets (n = 5) were slaughtered. Performance parameters such as feed intake, live weight gain and feed-to-gain ratio remained unaffected by the treatments. Uterus weights were significantly reduced in group FUS+ compared to FUS- (p = 0.028), while visceral organ weights were not influenced. Vulva width in relation to body weight was highest in group FUS- at the end of the trial, while hydrothermal treatment significantly reduced the parameter (p < 0.01). The highest toxin and toxin metabolite concentrations in serum were detected in group FUS-, whereas ingestion of diet FUS+ reduced the concentrations to the level of the control groups. Serum biochemical and haematological parameters were mainly within the given reference ranges and showed no treatment-related alterations. Stimulation of peripheral blood mononuclear cells was not affected. An effective detoxification of maize by hydrothermal treatment in the presence of SBS, methylamine and Ca(OH)2 could be demonstrated by means of serum toxin analyses. No undesired side effects of the treated-feed stuff or the chemicals themselves on the health of piglets were detected. PMID:23859352

  3. A Solution NMR Investigation into the Early Events of Amelogenin Nanosphere Self-Assembly Initiated with Sodium Chloride or Calcium Chloride†

    PubMed Central

    Buchko, Garry W.; Tarasevich, Barbara J.; Bekhazi, Jacky; Snead, Malcolm L.; Shaw, Wendy J.

    2009-01-01

    Using solution-state NMR spectroscopy, new insights into the early events governing amelogenin supramolecular self-assembly have been identified using sodium chloride and calcium chloride to trigger the association. Two-dimensional 1H–15N HSQC spectra were recorded for 15N- and 13C-labeled murine amelogenin as a function of increasing NaCl and CaCl2 concentration beginning with solution conditions of 2% acetic acid at pH 3.0, where amelogenin was monomeric. Residue specific changes in molecular dynamics, manifested by the reduction in intensity and disappearance of 1H–15N HSQC cross-peaks, were observed with the addition of either salt to the protein. With increasing NaCl concentrations, residues between T21 and R31 near the N-terminus were affected first, suggesting that these residues may initiate amelogenin dimerization, the first step in nanosphere assembly. At higher NaCl concentrations, more residues near the N-terminus (Y12–I51) were affected, and with further additions of NaCl, residues near the C-terminus (L141–T171) began to show a similar change in molecular dynamics. With increasing CaCl2 concentrations, a similar stepwise change in molecular dynamics involving essentially the same set of amelogenin residues was observed. As the concentration of either salt was increased, a concomitant increase in the estimated overall rotational correlation time (?c) was observed, consistent with assembly. Self-assembly into a dimer or trimer was established with dynamic light scattering studies under similar conditions that showed an increase in diameter of the smallest species from 4.1 nm in the absence of salt to ~10 nm in the presence of salt. These results suggest a possible stepwise interaction mechanism, starting with the N-terminus and followed by the C-terminus, leading to amelogenin nanosphere assembly. PMID:19086270

  4. Interactions of persistent sodium and calcium-activated nonspecific cationic currents yield dynamically distinct bursting regimes in a model of respiratory neurons.

    PubMed

    Dunmyre, Justin R; Del Negro, Christopher A; Rubin, Jonathan E

    2011-10-01

    The preBötzinger complex (preBötC) is a heterogeneous neuronal network within the mammalian brainstem that has been experimentally found to generate robust, synchronous bursts that drive the inspiratory phase of the respiratory rhythm. The persistent sodium (NaP) current is observed in every preBötC neuron, and significant modeling effort has characterized its contribution to square-wave bursting in the preBötC. Recent experimental work demonstrated that neurons within the preBötC are endowed with a calcium-activated nonspecific cationic (CAN) current that is activated by a signaling cascade initiated by glutamate. In a preBötC model, the CAN current was shown to promote robust bursts that experience depolarization block (DB bursts). We consider a self-coupled model neuron, which we represent as a single compartment based on our experimental finding of electrotonic compactness, under variation of g (NaP), the conductance of the NaP current, and g (CAN), the conductance of the CAN current. Varying these two conductances yields a spectrum of activity patterns, including quiescence, tonic activity, square-wave bursting, DB bursting, and a novel mixture of square-wave and DB bursts, which match well with activity that we observe in experimental preparations. We elucidate the mechanisms underlying these dynamics, as well as the transitions between these regimes and the occurrence of bistability, by applying the mathematical tools of bifurcation analysis and slow-fast decomposition. Based on the prevalence of NaP and CAN currents, we expect that the generalizable framework for modeling their interactions that we present may be relevant to the rhythmicity of other brain areas beyond the preBötC as well. PMID:21234794

  5. Effectiveness of a calcium sodium phosphosilicate containing prophylaxis paste in reducing dentine hypersensitivity immediately and 4 weeks after a single application: a double-blind randomized controlled trial

    PubMed Central

    Neuhaus, Klaus W; Milleman, Jeffery L; Milleman, Kimberly R; Mongiello, Kimberly A; Simonton, Thomas C; Clark, Courtney E; Proskin, Howard M; Seemann, Rainer

    2013-01-01

    Aims The aim of this single-site, randomized, controlled, double-blind, 3-arm parallel study was to determine the effectiveness of a prophylaxis paste containing 15% calcium sodium phosphosilicate (CSPS; NovaMin®) with and without fluoride in reducing dentine hypersensitivity immediately after a single application and 28 days following dental scaling and root planing. Materials & Methods Overall, 151 subjects were enrolled in this study. All subjects received a scaling and root planing procedure followed by a final prophylaxis step using one of three different prophylaxis pastes: Test-A (15% NovaMin® and NaF), Test-B (15% NovaMin®) and a control. Dentine hypersensitivity was assessed by tactile stimulus (Yeaple Probe®) and by air blast (Schiff scale) at baseline, immediately after and 28 days after a prophylaxis procedure. One hundred and forty-nine subjects completed the study. Results Subjects having received the test prophylaxis pastes showed statistically lower (anova, p < 0.05) dentine hypersensitivity compared with the control group immediately after the prophylaxis procedure (Yeaple Probe®: Test-A = 20.9 ± 12.6, Test-B = 22.7 ± 12.9, Control=11.2 ± 3.1; Schiff score: Test-A = 1.1 ± 0.6, Test-B = 1.1 ± 0.6, Control = 2.0 ± 0.7) and after 28 days (Yeaple probe: Test-A = 21.5 ± 11.9, Test-B = 20.6 ± 11.3, Control = 11.8 ± 6.0; Schiff score: Test-A = 1.0 ± 0.6, Test-B = 1.0 ± 0.6, Control = 2.0 ± 0.7). Conclusions In conclusion, the single application of both fluoridated and non-fluoridated prophylaxis pastes containing 15% CSPS (NovaMin®) provided a significant reduction of dentine hypersensitivity up to at least 28 days. PMID:23414245

  6. The Elimination of Sodium and Potassium Hydroxides from Desiccated Soda Lime Diminishes Degradation of Desflurane to Carbon Monoxide and Sevoflurane to Compound A but Does Not Compromise Carbon Dioxide Absorption

    Microsoft Academic Search

    M. A. Neumann; M. J. Laster; R. B. Weiskopf; D. H. Gong; R. Dudziak; E. I Eger II

    1999-01-01

    Normal (hydrated) soda lime absorbent (approxi- mately 95% calcium hydroxide (Ca(OH)2), the remain- ing 5% consisting of a mixture of sodium hydroxide (NaOH) and potassium hydroxide (KOH)) degrades sevoflurane to the nephrotoxin Compound A, and des- iccated soda lime degrades desflurane, enflurane, and isoflurane to carbon monoxide (CO). We examined whether the bases in soda lime differed in their capaci-

  7. 21 CFR 184.1229 - Calcium stearate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...1229 Calcium stearate. (a) Calcium stearate (Ca(C17 H35 COO...Reg. No. 1529-23-0) is the calcium salt of stearic acid derived...as a white precipitate by mixing calcium chloride and sodium stearate in...

  8. On the initial stages of cement hydration S. J. Preece, J. Billingham and A. C. King

    E-print Network

    Billingham, John

    products of C3S are hydrated calcium silicate C-S-H and calcium hydroxide CH. On contact with water, ions. In this paper we propose a reaction-di usion model for the hydration of tricalcium silicate, a principal con with experimental data. Keywords:cementhydration, tricalcium silicate, inductionperiod, reaction-di usion

  9. Strength and hydration properties of reactive MgO-activated ground granulated blastfurnace slag paste

    E-print Network

    Jin, Fei; Gu, Kai; Al-Tabbaa, Abir

    2014-12-10

    (internal) on the performance of AAS and revealed that the main hydration products are calcium silicate hydrate (C-S-H) gel and hydrotalcite-like phases (Ht), which are more voluminous than C-S-H, resulting in a less porous structure and higher strength... be achieved at the low w/c, which is attributed to better pore filling capacity of the hydration products. 4. The main hydration products are hydrotalcite-like phases (Ht) and calcium silicate hydrate (C-S-H), with the content increase with the increase...

  10. Standard enthalpies of formation of francium hydroxide hydrates

    Microsoft Academic Search

    Burylev

    1995-01-01

    Available experimental data on standard enthalpies of formation of alkali metal hydroxide hydrates have been summarized. Using equations derived, the authors have calculated previously unknown enthalpies of formation of some lithium, sodium, potassium, rubidium, and cesium hydroxide hydrates. Taking into account the contribution of water to the enthalpies of formation of monohydrates, the authors have estimated the enthalpies of formation

  11. Role of a novel maintained low-voltage-activated inward current permeable to sodium and calcium in pacemaking of insect neurosecretory neurons

    Microsoft Academic Search

    Antoine Defaix; Bruno Lapied

    2005-01-01

    Among ionic currents underlying neuronal pacemaker activity, low-threshold-activated calcium currents contribute to setting the threshold for spike firing. In the insect central nervous system, dorsal unpaired median (DUM) neurons are capable of generating spontaneous electrical activity. It has previously been shown that two distinct (transient and maintained) low-voltage-activated (LVA) calcium currents are responsible for the generation of the pacemaker potential.

  12. Identifying inhibitors of hydrate formation rate with viscometric experiments

    SciTech Connect

    Kalbus, J.S.; Christiansen, R.L.; Sloan, D. Jr.

    1995-12-31

    Inhibiting the rate of hydrate formation with low concentration additives is an economically and environmentally attractive alternative to prevention of hydrates with large doses of methanol. Here, a method for screening possible rate inhibitors is described. In the method, a viscometer is used to follow the development of hydrate formation for water-THF solutions and for water-gas solutions at conditions favoring hydrate formation. The method was applied to about 30 different chemicals, plus binary combinations of many of these chemicals. The best chemical additives included BASF F-127, Mirawet ASC, Surfynol-465, sodium dodecyl sulfate(SDS), Mirataine CBS with polyvinylpyrrolidone(PVP), and SDS with PVP.

  13. [Hydration for the prevention of contrast medium-induced nephropathy: an update].

    PubMed

    Heinrich, M; Uder, M

    2006-04-01

    Contrast medium-induced nephropathy (CIN) continues to be one of the most common causes of hospital-acquired acute renal failure. Since most of the clinical studies on the prophylactic use of different drugs to prevent CIN produced disappointing results, hydration remains the mainstay of prophylaxis. A number of recent prospective randomized trials provided further evidence of the effectiveness of hydration and relevant information regarding the optimization of hydration protocols. It was shown that a bolus hydration solely during examination is not sufficient to prevent CIN. In addition, isotonic 0.9 % saline was superior to the commonly used half-isotonic 0.45 % saline in another trial. An outpatient hydration protocol including oral hydration before the examination followed by forced intravenous hydration over 6 hrs. beginning 30 to 60 min. prior to examination seems to be comparable to the usual hydration over 24 hrs. Another hydration protocol, which could also be very attractive especially for outpatients, included the infusion of sodium bicarbonate. In a recent trial, hydration with sodium bicarbonate, given as a bolus for 1 hr. prior to examination followed by an infusion for 6 hrs. after examination, was more effective than hydration with sodium chloride for the prophylaxis of CIN. However, there is still a lack of large-scale, multi-center trials comparing different hydration protocols and investigating their influence on clinically relevant endpoints such as mortality or the need for dialysis. PMID:16612729

  14. Inhibition of Reverse-Mode Sodium-Calcium Exchanger Activity and Apoptosis by Levosimendan in Human Cardiomyocyte Progenitor Cell-Derived Cardiomyocytes after Anoxia and Reoxygenation

    PubMed Central

    Li, Ping-Chun; Yang, Ya-Chi

    2014-01-01

    Levosimendan, a known calcium sensitizer with positive inotropic and vasodilating properties, might also be cardioprotective during ischemia-reperfusion (I/R) insult. Its effects on calcium homeostasis and apoptosis in I/R injury remain unclear. Na+/Ca2+ exchanger (NCX) is a critical mediator of calcium homeostasis in cardiomyocytes, with reverse-mode NCX activity responsible for intracellular calcium overload and apoptosis of cardiomyocytes during I/R. We probed effects and underlying mechanisms of levosimendan on apoptosis and NCX activity in cultured human cardiomyocyte progenitor cells (CPC)-derived cardiomyocytes undergoing anoxia-reoxygenation (A/R), simulating I/R in vivo. Administration of levosimendan decreased apoptosis of CPC-derived cardiomyocytes induced by A/R. The increase in reverse-mode NCX activity after A/R was curtailed by levosimendan, and NCX1 was translocated away from the cell membrane. Concomitantly, endoplasmic reticulum (ER) stress response induced by A/R was attenuated in CPC-derived cardiomycytes treated with NCX-targeted siRNA or levosimendan, with no synergistic effect between treatments. Results indicated levosimendan inhibited reverse-mode NCX activity to protect CPC-derived cardiomyocytes from A/R-induced ER stress and cell death. PMID:24498266

  15. Co-Localization of Sodium Channel Na[v]1.6 and the Sodium--Calcium Exchanger at Sites of Axonal Injury in the Spinal Cord in EAE

    ERIC Educational Resources Information Center

    Craner, Matthew J.; Hains, Bryan C.; Lo, Albert C.; Black, Joel A.; Waxman, Stephen G.

    2004-01-01

    Axonal degeneration contributes to the development of non-remitting neurological deficits and disability in multiple sclerosis, but the molecular mechanisms that underlie axonal loss in multiple sclerosis are not clearly understood. Studies of white matter axonal injury have demonstrated that voltage-gated sodium channels can provide a route for…

  16. Combinatorial molecular optimization of cement hydrates

    PubMed Central

    Abdolhosseini Qomi, M.J.; Krakowiak, K.J.; Bauchy, M.; Stewart, K.L.; Shahsavari, R.; Jagannathan, D.; Brommer, D.B.; Baronnet, A.; Buehler, M.J.; Yip, S.; Ulm, F.-J; Van Vliet, K.J.; Pellenq, R.J-.M.

    2014-01-01

    Despite its ubiquitous presence in the built environment, concrete’s molecular-level properties are only recently being explored using experimental and simulation studies. Increasing societal concerns about concrete’s environmental footprint have provided strong motivation to develop new concrete with greater specific stiffness or strength (for structures with less material). Herein, a combinatorial approach is described to optimize properties of cement hydrates. The method entails screening a computationally generated database of atomic structures of calcium-silicate-hydrate, the binding phase of concrete, against a set of three defect attributes: calcium-to-silicon ratio as compositional index and two correlation distances describing medium-range silicon-oxygen and calcium-oxygen environments. Although structural and mechanical properties correlate well with calcium-to-silicon ratio, the cross-correlation between all three defect attributes reveals an indentation modulus-to-hardness ratio extremum, analogous to identifying optimum network connectivity in glass rheology. We also comment on implications of the present findings for a novel route to optimize the nanoscale mechanical properties of cement hydrate. PMID:25248305

  17. Combinatorial molecular optimization of cement hydrates

    NASA Astrophysics Data System (ADS)

    Abdolhosseini Qomi, M. J.; Krakowiak, K. J.; Bauchy, M.; Stewart, K. L.; Shahsavari, R.; Jagannathan, D.; Brommer, D. B.; Baronnet, A.; Buehler, M. J.; Yip, S.; Ulm, F.-J.; van Vliet, K. J.; Pellenq, R. J.-. M.

    2014-09-01

    Despite its ubiquitous presence in the built environment, concrete’s molecular-level properties are only recently being explored using experimental and simulation studies. Increasing societal concerns about concrete’s environmental footprint have provided strong motivation to develop new concrete with greater specific stiffness or strength (for structures with less material). Herein, a combinatorial approach is described to optimize properties of cement hydrates. The method entails screening a computationally generated database of atomic structures of calcium-silicate-hydrate, the binding phase of concrete, against a set of three defect attributes: calcium-to-silicon ratio as compositional index and two correlation distances describing medium-range silicon-oxygen and calcium-oxygen environments. Although structural and mechanical properties correlate well with calcium-to-silicon ratio, the cross-correlation between all three defect attributes reveals an indentation modulus-to-hardness ratio extremum, analogous to identifying optimum network connectivity in glass rheology. We also comment on implications of the present findings for a novel route to optimize the nanoscale mechanical properties of cement hydrate.

  18. Combinatorial molecular optimization of cement hydrates.

    PubMed

    Abdolhosseini Qomi, M J; Krakowiak, K J; Bauchy, M; Stewart, K L; Shahsavari, R; Jagannathan, D; Brommer, D B; Baronnet, A; Buehler, M J; Yip, S; Ulm, F-J; Van Vliet, K J; Pellenq, R J-M

    2014-01-01

    Despite its ubiquitous presence in the built environment, concrete's molecular-level properties are only recently being explored using experimental and simulation studies. Increasing societal concerns about concrete's environmental footprint have provided strong motivation to develop new concrete with greater specific stiffness or strength (for structures with less material). Herein, a combinatorial approach is described to optimize properties of cement hydrates. The method entails screening a computationally generated database of atomic structures of calcium-silicate-hydrate, the binding phase of concrete, against a set of three defect attributes: calcium-to-silicon ratio as compositional index and two correlation distances describing medium-range silicon-oxygen and calcium-oxygen environments. Although structural and mechanical properties correlate well with calcium-to-silicon ratio, the cross-correlation between all three defect attributes reveals an indentation modulus-to-hardness ratio extremum, analogous to identifying optimum network connectivity in glass rheology. We also comment on implications of the present findings for a novel route to optimize the nanoscale mechanical properties of cement hydrate. PMID:25248305

  19. Final amended report on the safety assessment of Ammonium Thioglycolate, Butyl Thioglycolate, Calcium Thioglycolate, Ethanolamine Thioglycolate, Ethyl Thioglycolate, Glyceryl Thioglycolate, Isooctyl Thioglycolate, Isopropyl Thioglycolate, Magnesium Thioglycolate, Methyl Thioglycolate, Potassium Thioglycolate, Sodium Thioglycolate, and Thioglycolic Acid.

    PubMed

    Burnett, Christina L; Bergfeld, Wilma F; Belsito, Donald V; Klaassen, Curtis D; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2009-01-01

    This safety assessment includes Ammonium and Glyceryl Thioglycolate and Thioglycolic Acid Butyl, Calcium, Ethanolamine, Ethyl, Isooctyl, Isopropyl, Magnesium, Methyl, Potassium, and Sodium Thioglycolate, as used in cosmetics. Thioglycolates penetrate skin and distribute to the kidneys, lungs, small intestine, and spleen; excretion is primarily in urine. Thioglycolates were slightly toxic in rat acute oral toxicity studies. Thioglycolates are minimal to severe ocular irritants. Thioglycolates can be skin irritants in animal and in vitro tests, and can be sensitizers. A no-observable-adverse-effect level for reproductive and developmental toxicity of 100 mg/kg per day was determined using rats. Thioglycolates were not mutagenic, and there was no evidence of carcinogenicity. Thioglycolates were skin irritants in some clinical tests. Clinically significant adverse reactions to these ingredients used in depilatories are not commonly seen, suggesting current products are formulated to be practically nonirritating under conditions of recommended use. Formulators should take steps necessary to assure that current practices are followed. PMID:19636068

  20. Identification of Mutations in SLC24A4, Encoding a Potassium-Dependent Sodium/Calcium Exchanger, as a Cause of Amelogenesis Imperfecta

    PubMed Central

    Parry, David A.; Poulter, James A.; Logan, Clare V.; Brookes, Steven J.; Jafri, Hussain; Ferguson, Christopher H.; Anwari, Babra M.; Rashid, Yasmin; Zhao, Haiqing; Johnson, Colin A.; Inglehearn, Chris F.; Mighell, Alan J.

    2013-01-01

    A combination of autozygosity mapping and exome sequencing identified a null mutation in SLC24A4 in a family with hypomineralized amelogenesis imperfect a (AI), a condition in which tooth enamel formation fails. SLC24A4 encodes a calcium transporter upregulated in ameloblasts during the maturation stage of amelogenesis. Screening of further AI families identified a missense mutation in the ion-binding site of SLC24A4 expected to severely diminish or abolish the ion transport function of the protein. Furthermore, examination of previously generated Slc24a4 null mice identified a severe defect in tooth enamel that reflects impaired amelogenesis. These findings support a key role for SLC24A4 in calcium transport during enamel formation. PMID:23375655

  1. Conservation of body calcium by increased dietary intake of potassium: A potential measure to reduce the osteoporosis process during prolonged exposure to microgravity

    NASA Technical Reports Server (NTRS)

    Nechay, Bohdan R.

    1989-01-01

    During the 1988 NASA Summer Faculty Fellowship Program, it was proposed that the loss of skeletal calcium upon prolonged exposure to microgravity could be explained, in part, by a renal maladjustment characterized by an increased urinary excretion of calcium. It was theorized that because the conservation of body fluids and electrolytes depends upon the energy of adenosine triphosphate and enzymes that control the use of its energy for renal ion transport, an induction of renal sodium and potassium-dependent adenosine triphosphatase (Na + K ATPase) by oral loading with potassium would increase the reabsorption of sodium directly and that of calcium indirectly, leading to improved hydration and to reduced calcium loss. Preliminary studies showed the following. Rats drinking water containing 0.2 M potassium chloride for six to 13 days excreted in urine 22 muEq of calcium and 135 muEq of sodium per 100 grams of body weight per day. The corresponding values for control rats drinking tap water were 43 muEq and 269 muEq respectively. Renal Na + K ATPase activity in potassium loaded rats was higher than in controls. Thus, oral potassium loading resulted in increased Na + K ATPase activity and diminished urinary excretion of calcium and of sodium as predicted by the hypothesis. An extension of these studies to humans has the potential of resulting in development of harmless, non-invasive, drug-free, convenient measures to reduce bone loss and other electrolyte and fluid problems in space travelers exposed to prolonged periods of microgravity.

  2. Phase transitions in biogenic amorphous calcium carbonate

    NASA Astrophysics Data System (ADS)

    Gong, Yutao

    Geological calcium carbonate exists in both crystalline phases and amorphous phases. Compared with crystalline calcium carbonate, such as calcite, aragonite and vaterite, the amorphous calcium carbonate (ACC) is unstable. Unlike geological calcium carbonate crystals, crystalline sea urchin spicules (99.9 wt % calcium carbonate and 0.1 wt % proteins) do not present facets. To explain this property, crystal formation via amorphous precursors was proposed in theory. And previous research reported experimental evidence of ACC on the surface of forming sea urchin spicules. By using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), we studied cross-sections of fresh sea urchin spicules at different stages (36h, 48h and 72h after fertilization) and observed the transition sequence of three mineral phases: hydrated ACC ? dehydrated ACC ? biogenic calcite. In addition, we unexpectedly found hydrated ACC nanoparticles that are surrounded by biogenic calcite. This observation indicates the dehydration from hydrated ACC to dehydrated ACC is inhibited, resulting in stabilization of hydrated ACC nanoparticles. We thought that the dehydration was inhibited by protein matrix components occluded within the biomineral, and we designed an in vitro assay to test the hypothesis. By utilizing XANES-PEEM, we found that SM50, the most abundant occluded matrix protein in sea urchin spicules, has the function to stabilize hydrated ACC in vitro.

  3. Fluoride coatings make effective lubricants in molten sodium environment

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Coating bearing surfaces with calcium fluoride-barium fluoride film provides effective lubrication against sliding friction in molten sodium and other severe environments at high and low temperatures.

  4. Modeling and simulation of cement hydration kinetics and microstructure development

    SciTech Connect

    Thomas, Jeffrey J., E-mail: jthomas39@slb.com [Schlumberger-Doll Research, Cambridge, MA 02139 (United States); Biernacki, Joseph J. [Department of Chemical Engineering, Tennessee Tech University, Cookeville, TN (United States); Bullard, Jeffrey W. [Materials and Construction Research Division, National Institute of Standards and Technology, Gaithersburg, MD (United States); Bishnoi, Shashank [Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi (India); Dolado, Jorge S. [Center for Nanomaterials Application in Construction, LABEIN-Tecnalia, Bilbao (Spain); Scherer, George W. [Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ (United States); Luttge, Andreas [Department of Chemistry, Rice University, Houston, TX (United States)

    2011-12-15

    Efforts to model and simulate the highly complex cement hydration process over the past 40 years are reviewed, covering different modeling approaches such as single particle models, mathematical nucleation and growth models, and vector and lattice-based approaches to simulating microstructure development. Particular attention is given to promising developments that have taken place in the past few years. Recent applications of molecular-scale simulation methods to understanding the structure and formation of calcium-silicate-hydrate phases, and to understanding the process of dissolution of cement minerals in water are also discussed, as these topics are highly relevant to the future development of more complete and fundamental hydration models.

  5. Computer Simulation of Cosolvent Effects on Hydrophobic Hydration Paul E. Smith*

    E-print Network

    Smith, Paul E.

    for helium, neon, argon, and methane solutes in solutions of sodium chloride, ammonium sulfate, calcium chloride, ammonium acetate, tetramethylammonium chloride, guanidinium chloride, urea, and TFE. The effects

  6. Technische Universitt Berlin Fakultt fr Verkehrs-und Maschinensysteme , Institut fr Mechanik

    E-print Network

    Berlin,Technische Universität

    toothpaste Composition: Calcium Carbonate, Aqua, Sorbitol, Hydrated Silica, Sodium Laury Sulfate, Sodium Silicate, Sodium Monofluorophosphate, Aroma, Cellulose Gum, Potassium Citrate, Benzyl Alcohol, Sodium

  7. Long-term behaviour of hydraulic binders based on calcium sulfoaluminate and calcium sulfosilicate

    Microsoft Academic Search

    N. Sherman; J. Beretka; L. Santoro; G. L. Valenti

    1995-01-01

    Hydration, physico-mechanical and carbonation studies have been carried out on the ternary system of calcium sulfoaluminate (C4A3S?), calcium sulfosilicate (C5S2S?) and anhydrite (CS?), synthesised by single firing at 1200 °C. The raw materials used were natural materials, viz. limestone, bauxite and clay, and also industrial process; wastes and by-products, viz. phosphogypsum, fly ash and blast furnace slag.These clinkers containing calcium

  8. Hydrate characterization research overview

    SciTech Connect

    Malone, R.D.

    1993-06-01

    Gas hydrate research has been focused primarily on the development of a basic understanding of hydrate formation and dissociation in the laboratory, as well as in the field. Laboratory research on gas hydrates characterized the physical system, which focused on creating methane hydrates samples, tetrahydrofuran (THF) hydrate samples, consolidated rock samples, frost base mixtures, water/ice-base mixtures, and water-base mixtures. Laboratory work produced measurements of sonic velocity and electrical resistivity of hydrates. As work progressed, areas, such as the Gulf of Mexico and the Guatemala Trench, where gas hydrates are likely to occur were identified, and specific high potential areas were targeted for detailed investigation. The testing of samples and recovered cores from such areas provided information for detection of hydrate formations in the natural environment. Natural gas hydrate samples have been tested for thermal properties, dissociation properties, fracture mechanics, and optical properties. Acoustical properties were investigated both in the laboratory and, as possible, in the field. Sonic velocity and electrical resistivity measurements will continue to be obtained. These activities have been undertaken in hydrate deposits on Alaska`s North Slope, the Gulf of Mexico and the US East coast offshore, as well as other gas hydrate target areas.

  9. 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 ...

  10. 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 ...

  11. Calcium supplements

    MedlinePLUS

    ... enough calcium over your lifetime can help prevent osteoporosis . Most people get enough calcium in their normal diet. Calcium is found in dairy foods and leafy green vegetables. Older women and men ...

  12. CONTROL OF SOX EMISSIONS BY IN-FURNACE SORBENT INJECTION: CARBONATES VS HYDRATES

    EPA Science Inventory

    The paper provides high-temperature isothermal data on SO2 capture by calcium-based sorbents, obtained in a dispersed-phase reactor for limestones, dolomites, hydrated calcitic limes, and hydrated dolomitic limes as a function of Ca/S molar ratio, temperature, and SO2 partial pre...

  13. The growth rate of gas hydrate from refrigerant R12

    SciTech Connect

    Kendoush, Abdullah Abbas; Jassim, Najim Abid [Centre of Engineering Physics, Ministry of Sciences and Technology, P.O. Box 765, Baghdad (Iraq); Joudi, Khalid A. [Al-Nahrain University, Baghdad (Iraq)

    2006-07-15

    Experimental and theoretical investigations were presented dealing with three phase direct-contact heat transfer by evaporation of refrigerant drops in an immiscible liquid. Refrigerant R12 was used as the dispersed phase, while water and brine were the immiscible continuous phase. A numerical solution is presented to predict the formation rate of gas hydrates in test column. The solution provided an acceptable agreement when compared with experimental results. The gas hydrate growth rate increased with time. It increased with increasing dispersed phase flow rate. The presence of surface-active sodium chloride in water had a strong inhibiting effect on the gas hydrate formation rate. (author)

  14. Effect of dietary sodium zeolite A and graded levels of calcium and phosphorus on growth, plasma, and tibia characteristics of chicks.

    PubMed

    Watkins, K L; Southern, L L

    1992-06-01

    Sodium zeolite A (SZA), a synthetic sodium aluminosilicate having a high ion exchange capacity, has been shown to influence Ca and P utilization in chickens. A 3 x 2 x 2 factorial arrangement of treatments was used to investigate the effect of dietary P (.41, .55, and .69% total P), Ca (.6 and 1%), and SZA (0 and .75%) on growth, plasma, and tibia characteristics of chicks from 5 to 15 days of age. Growth, feed intake, gain:feed ratio, and tibia characteristics were influenced by dietary Ca and P in a manner consistent with dietary recommendations for these macro minerals. The addition of Ca, SZA, or both exacerbated the adverse effects of feeding low-P diets, yet alleviated the adverse effects of feeding a low-Ca, high-P diet. Dietary SZA had no effect (P greater than .5) on plasma Ca or alkaline phosphatase; however, SZA reduced (P less than .01) plasma P. Dietary SZA increased (P less than .02) tibia Mn, Zn, Cu, and Al. The SZA-induced increase in tibia Al was most evident in chicks fed low levels of P (SZA by P interaction, P less than .02). The overall response to dietary SZA addition paralleled the response observed from Ca supplementation, indicating that SZA increased Ca utilization, reduced P utilization, or contributed to both of these effects. These data demonstrate that the effects of SZA are influenced by the dietary concentration of Ca and P and that the addition of SZA to diets low in P results in bone Al accumulation. PMID:1319580

  15. Effect of temperature on hydration kinetics and polymerization of tricalcium silicate in stirred suspensions of CaO-saturated solutions

    SciTech Connect

    Grant, Steven A. [U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290 (United States)]. E-mail: steven.a.grant@usace.army.mil; Boitnott, Ginger E. [U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290 (United States); Korhonen, Charles J. [U.S. Army Engineer Research and Development Center, Cold Regions Research and Engineering Laboratory, 72 Lyme Road, Hanover, NH 03755-1290 (United States); Sletten, Ronald S. [Quaternary Research Center, University of Washington, Seattle (United States)

    2006-04-15

    Tricalcium silicate was hydrated at 274, 278, 283, 298, and 313 K in stirred suspensions of saturated CaO solutions under a nitrogen-gas atmosphere until the end of deceleratory period. The suspension conductivities and energy flows were measured continuously. The individual reaction rates for tricalcium silicate dissolution, calcium silicate hydrate precipitation, and calcium hydroxide precipitation were calculated from these measurements. The results suggest that the proportion of tricalcium silicate dissolved was determined by the rate of tricalcium silicate dissolution and the time to very rapid calcium hydroxide precipitation. The time to very rapid calcium hydroxide precipitation was more sensitive to changes in temperature than was the rate of tricalcium silicate dissolution, so that the proportion of tricalcium silicate hydration dissolved by the deceleratory period increased with decreasing temperature. The average chain length of the calcium silicate hydrate ascertained by magic-angle spinning nuclear magnetic resonance spectroscopy increased with increasing temperature.

  16. Methane Hydrate Field Program

    SciTech Connect

    None

    2013-12-31

    This final report document summarizes the activities undertaken and the output from three primary deliverables generated during this project. This fifteen month effort comprised numerous key steps including the creation of an international methane hydrate science team, determining and reporting the current state of marine methane hydrate research, convening an international workshop to collect the ideas needed to write a comprehensive Marine Methane Hydrate Field Research Plan and the development and publication of that plan. The following documents represent the primary deliverables of this project and are discussed in summary level detail in this final report. • Historical Methane Hydrate Project Review Report • Methane Hydrate Workshop Report • Topical Report: Marine Methane Hydrate Field Research Plan • Final Scientific/Technical Report

  17. Origins of hydration lubrication

    NASA Astrophysics Data System (ADS)

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-01

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4–1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  18. Hydration-dependent dynamic crossover phenomenon in protein hydration water

    E-print Network

    Wang, Zhe

    The characteristic relaxation time ? of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level h[subscript c] =0.2–0.25 ...

  19. The Nitric Oxide Donor SNAP-Induced Amino Acid Neurotransmitter Release in Cortical Neurons. Effects of Blockers of Voltage-Dependent Sodium and Calcium Channels

    PubMed Central

    Merino, José Joaquín; Arce, Carmen; Naddaf, Ahmad; Bellver-Landete, Victor; Oset-Gasque, Maria Jesús; González, María Pilar

    2014-01-01

    Background The discovery that nitric oxide (NO) functions as a signalling molecule in the nervous system has radically changed the concept of neuronal communication. NO induces the release of amino acid neurotransmitters but the underlying mechanisms remain to be elucidated. Findings The aim of this work was to study the effect of NO on amino acid neurotransmitter release (Asp, Glu, Gly and GABA) in cortical neurons as well as the mechanism underlying the release of these neurotransmitters. Cortical neurons were stimulated with SNAP, a NO donor, and the release of different amino acid neurotransmitters was measured by HPLC. The involvement of voltage dependent Na+ and Ca2+ channels as well as cGMP in its mechanism of action was evaluated. Conclusions Our results indicate that NO induces release of aspartate, glutamate, glycine and GABA in cortical neurons and that this release is inhibited by ODQ, an inhibitor of soluble guanylate cyclase. Thus, the NO effect on amino acid neurotransmission could be mediated by cGMP formation in cortical neurons. Our data also demonstrate that the Na+ and Ca2+ voltage- dependent calcium channels are involved in the NO effects on cortical neurons. PMID:24598811

  20. Class H cement hydration at 180 °C and high pressure in the presence of added silica

    SciTech Connect

    Jupe, Andrew C.; Wilkinson, Angus P.; Luke, Karen; Funkhouser, Gary P. (Halliburton); (GIT)

    2008-10-06

    Under deep oil-well conditions of elevated temperature and pressure, crystalline calcium silicate hydrates are formed during Portland cement hydration. The use of silica rich mineral additives leads to the formation of crystalline hydrates with better mechanical properties than those formed without the additive. The effects of silica flour, silica fume (amorphous silica), and a natural zeolite mixture on the hydration of Class H cement slurries at 180 C under externally applied pressures of 7 and 52 MPa are examined in real time using in-situ synchrotron X-ray diffraction. For some compositions examined, but not all, pressure was found to have a large effect on the kinetics of crystalline hydrate formation. The use of silica fume delayed both C{sub 3}S hydration and the formation of crystalline silicate hydrates compared to what was seen with other silica sources.

  1. The Effect of Modified Atmosphere Packaging and Addition of Rosemary Extract, Sodium Acetate and Calcium Lactate Mixture on the Quality of Pre-cooked Hamburger Patties during Refrigerated Storage

    PubMed Central

    Muhlisin; Kang, Sun Moon; Choi, Won Hee; Lee, Keun Taik; Cheong, Sung Hee; Lee, Sung Ki

    2013-01-01

    The effect of modified atmosphere packaging (MAP; 30% CO2+70% N2 or 100% N2) and an additive mixture (500 ppm rosemary extract, 3,000 ppm sodium acetate and 1,500 ppm calcium lactate) on the quality of pre-cooked hamburger patties during storage at 5°C for 14 d was evaluated. The addition of the additive mixture reduced aerobic and anaerobic bacteria counts in both 30% CO2-MAP (30% CO2+70% N2) and 100% N2-MAP (p<0.05). The 30% CO2-MAP was more effective to suppress the microbial growth than 100% N2-MAP, moreover the 30% CO2-MAP combined with additive mixture resulted in the lowest bacterial counts. The hamburger patties with additive mixture showed lower CIE L* and CIE a*, and higher CIE b* than those with no additive mixture. The 30% CO2-MAP tended to decrease the TBARS during storage regardless of the addition of additives. The use of 30% CO2-MAP in combination with additives mixture was effective for maintaining the quality and extending the shelf-life of pre-cooked hamburger patties. PMID:25049716

  2. [Effect of intra-duodenal administration of HCl and NaHCO3 on the secretion and content of sodium, potassium and calcium in the pancreatic juice and bile of sheep].

    PubMed

    Studzi?ski, T; Bobowiec, R

    1979-01-01

    The experiments were carried out on 3 sheep with a Harrison type cannula inserted into the funds of the gall-bladder enabling to obtain bile and with a Herrera type cannula fixed in the duodenum enabling to sample pancreatic juice. Administration of 3 mEq HCl in 50 ml of solution to the duodenum increased the volume of secreted bile from 6,04 ml to 8,11 ml/15 min with no essential changes in the volume of pancreatic juice. Administration of 15 mEq NaHCO3 in 50 ml of solution decreased the volume of secreted bile from 6.73 ml to 4,15 ml/15 min and decreased pancreatic juice from 5,46 ml to 4.72 ml/15 min. Intravenous administration of secret increased the volume of both pancreatic juice and bile. Administration of HCl and NaHCO3 solution to the duodenum did not cause changes in the concentration and secretion of sodium, potassium and calcium in pancreatic juice and bile. The results point to the predominance of the secretory function of bile over pancreatic juice in sheep after stimulation of the duodenum with the investigated substances. PMID:555512

  3. Dietary Sodium

    MedlinePLUS

    Table salt is made up of the elements sodium and chlorine - the technical name for salt is sodium chloride. Your body needs some sodium to work properly. ... to healthy eating is choosing foods low in salt and sodium. Doctors recommend you eat less than ...

  4. Ventricular and atrial electrophysiological effects of a IC antiarrhythmic drug, cibenzoline, in the innervated dog heart. Role of sodium and calcium channels.

    PubMed

    Timour, Q; Aupetit, J F; Loufoua-Moundanga, J; Bertrix, L; Freysz, M; Faucon, G

    1989-09-01

    The effects of cibenzoline, rightly known as a sodium channel inhibitor (class IC antiarrhythmic drug), were investigated in anaesthetized, closed-chest dogs, on conduction in the contractile fibres, ventricular and atrial, the His-Purkinje system and the atrioventricular node. In ventricular muscle, conduction time was measured between base and apex by two endocavitary electrodes. The other conduction times were obtained from the recording of the His bundle potentials. In addition, effective refractory period was determined by the extrastimulus method in ventricular and atrial muscle and in the atrioventricular node, and sinus rate monitored in the intervals of pacing periods. In the absence of vagal tone, cibenzoline in 4 mg.kg-1 dose prolonged conduction times in the ventricular contractile tissue, His-Purkinje system and atrial contractile tissue to a large extent, but decreasingly from the former to the latter. This prolongation was antagonized by hypernatremia (174 mmol.l-1). In contrast, conduction time in the atrioventricular node, effective refractory periods and sinus rate were very little influenced. In the presence of vagal tone, the prolongation of conduction times in the ventricular contractile tissue. His-Purkinje system and atrial contractile tissue did not differ substantially from previously. It was the same for ventricular effective refractory period. But atrial effective refractory period was then considerably lengthened, while conduction time and effective refractory period in the atrioventricular node were greatly shortened and sinus rate notably accelerated.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2554155

  5. Surface modification of calcium carbonate: radical graft polymerization of vinyl monomers onto calcium carbonate surface initiated by azo groups introduced onto the surface

    Microsoft Academic Search

    Yukio Shirai; Kazuyo Seno; Takamitsu Da; Norio Tsubokawa

    1996-01-01

    —The preparation of calcium carbonate modified by 12-hydroxystearate groups and the grafting of polymers onto the surface by the polymerization of vinyl monomers initiated by azo groups introduced onto the surface were investigated. The preparation of calcium carbonate modified by 12-hydroxystearate was achieved by the reaction of calcium chloride with sodium carbonate containing a small amount of sodium 12-hydroxystearate. The

  6. Stimulation of ileal calcium absorption by sorbitol, L-xylose, or creatine via a decrease in luminal sodium concentration: relation with concomitant changes in enterocyte energy metabolism.

    PubMed

    Tardivel, S; Fournier, P; Dupuis, Y; Nabarra, B; Drueke, T; Lacour, B

    1994-04-01

    Ligated ileal loops, 30 cm in length, of 4-month-old male Wistar rats were instilled with 3 ml of a 10 mM CaCl2 solution (added with 0.25 muCi 45Ca) in the absence (control) or presence of 100mM sorbitol, L-xylose, or creatine. Ileal calcium (Ca) transport, measured by plasma 45Ca appearance, was found to be similar 30 minutes after fluid instillation in all four instances. However, thereafter, 45Ca appearance in plasma did not increase further in control animals whereas it increased twice as much during the subsequent 30 minutes in the presence of sorbitol, L-xylose, or creatine. However, when loops of similar length were instilled with only 1.0 ml of such solutions, the sorbitol effect was already observed during the first 30 minutes. The stimulation of ileal Ca absorption induced by the presence of sorbitol appeared to be due to a cellular effect, associated with a decreased flux across the paracellular pathway, as indicated by 3H-mannitol absorption. The presence of sorbitol in instilled ileal solution induced a significant decrease in luminal Na, K, bicarbonate, and Cl concentrations at each time point studied (30, 60, 120, or 240 minutes after instillation). Thirty minutes after instillation, no difference in soluble Ca concentration was observed between control and experimental rats. After 60 minutes, Ca concentration was dramatically decreased in control rats but it remained nearly constant in experimental animals. Thus, the presence of substances enhancing ileal Ca transport favored the maintenance of soluble Ca in ileal solution during longer time periods than their absence. In the ileal enterocyte, these substances induced a twofold increase of ATP content compared with controls.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8062145

  7. Vibrational spectra of the two hydrates of strontium oxalate.

    PubMed

    D'Antonio, Maria C; Torres, María M; Palacios, Daniel; González-Baró, Ana C; Baran, Enrique J

    2015-02-25

    The infrared and Raman spectra of the two hydrates of strontium oxalate, SrC2O4?H2O and SrC2O4?2H2O, were recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of the related calcium oxalates and other previously investigated metallic oxalates. PMID:25238188

  8. Vibrational spectra of the two hydrates of strontium oxalate

    NASA Astrophysics Data System (ADS)

    D'Antonio, Maria C.; Torres, María M.; Palacios, Daniel; González-Baró, Ana C.; Baran, Enrique J.

    2015-02-01

    The infrared and Raman spectra of the two hydrates of strontium oxalate, SrC2O4?H2O and SrC2O4?2H2O, were recorded and discussed on the basis of their structural peculiarities and in comparison with the spectra of the related calcium oxalates and other previously investigated metallic oxalates.

  9. Effects of ibandronate sodium, a nitrogen-containing bisphosphonate, on intermediate-conductance calcium-activated potassium channels in osteoclast precursor cells (RAW 264.7).

    PubMed

    Wu, Sheng-Nan; Huang, Yan-Ming; Liao, Yu-Kai

    2015-02-01

    Ibanonate sodium (Iban), a nitrogen-containing bisphosphonate, is recognized to reduce skeletal complications through an inhibition of osteoclast-mediated bone resorption. However, how this drug interacts with ion channels in osteoclasts and creates anti-osteoclastic activity remains largely unclear. In this study, we investigated the possible effects of Iban and other related compounds on ionic currents in the osteoclast precursor RAW 264.7 cells. Iban suppressed the amplitude of whole-cell K(+) currents (I K) in a concentration-dependent manner with an IC50 value of 28.9 ?M. The I K amplitude was sensitive to block by TRAM-34 and Iban-mediated inhibition of I K was reversed by further addition of DCEBIO, an activator of intermediate-conductance Ca(2+)-activated K(+) (IKCa) channels. Intracellular dialysis with Iban diminished I K amplitude and further addition of ionomycin reversed its inhibition. In 17?-estradiol-treated cells, Iban-mediated inhibition of I K remained effective. In cell-attached current recordings, Iban applied to bath did not modify single-channel conductance of IKCa channels; however, it did reduce channel activity. Iban-induced inhibition of IKCa channels was voltage-dependent. As IKCa-channel activity was suppressed by KN-93, subsequent addition of Iban did not further decrease the channel open probability. Iban could not exert any effect on inwardly rectifying K(+) current in RAW 264.7 cells. Under current-clamp recordings, Iban depolarized the membrane of RAW 264.7 cells and DCEBIO reversed Iban-induced depolarization. Iban also suppressed lipopolysaccharide-stimulated migration of RAW 264.7 cells in a concentration-dependent manner. Therefore, the inhibition by Iban of IKCa channels would be an important mechanism underlying its actions on the functional activity of osteoclasts occurring in vivo. PMID:25362532

  10. Inhibition of heart calcium and chloride currents by sodium iodide. Specific attenuation in cAMP-dependent protein kinase-mediated regulation

    PubMed Central

    1992-01-01

    The enzymes cAMP-dependent protein kinase (PKA) and protein kinase C (PKC) regulate the activity of cardiac ion channel proteins. In this study the whole-cell arrangement of the patch clamp technique was used to examine the effect of NaI on PKA-stimulated Cl- and Ca2+ channels in isolated guinea pig ventricular myocytes. Cl- currents (ICl) activated either by the beta-adrenergic agonist isoproterenol or the membrane- soluble cAMP analogue, 8-chlorphenylthio (8-CPT) cAMP, were greatly reduced in amplitude after substitution of an external solution containing 140 mM NaCl with a solution containing 140 mM NaI. This reduction was accompanied by a shift of -7 mV in the reversal potential (Erev) for ICl and could be reversed upon return to the NaCl external solution. Inhibition of ICl by NaI occurred in a concentration- dependent manner and was more pronounced for inward ICl (IC50 = 19 mM at -60 mV) than for outward ICl (IC50 = 60 mM at +60 mV). In contrast to ICl activated by PKA, ICl activated by PKC was slightly augmented in the presence of NaI and the Erev was found to shift by -15 mV. Based on these data, the relative permeability of I- to Cl- (PI/PCl) for this channel was calculated to be 1.79. NaI produced no change in the amplitude of inward calcium currents (ICa) recorded under basal conditions, but strongly inhibited ICa augmented by isoproterenol and 8- CPT cAMP, and during dialysis of cells with the catalytic subunit of PKA (CS). The in vitro incorporation of [gamma-32P]ATP into histone IIA and Kemptide, measured in the presence of PKA and cAMP, was not significantly different in assay mixtures containing salts of Cl- and I- . However, the ability of isoproterenol to augment basal ICa in whole- cell experiments was attenuated when experiments were carried out entirely in NaI external solution. Thus, the reduction in ICl and ICa observed in this study may result from a direct effect of I- on the phosphorylation/dephosphorylation of cardiac ion channel proteins or associated regulatory proteins. PMID:1282146

  11. Gas Hydrates Burning

    USGS Multimedia Gallery

    An image of gas hydrates burning. Gas hydrates are naturally-occurring “ice-like” combinations of natural gas and water that have the potential to provide an immense resource of natural gas from the world’s oceans and polar regions....

  12. Mallik Gas Hydrate Sample

    USGS Multimedia Gallery

    A sample of gas hydrates collected from Mallik, Canada. Gas hydrates are naturally-occurring “ice-like” combinations of natural gas and water that have the potential to provide an immense resource of natural gas from the world’s oceans and polar regions....

  13. A multiphase model for the early stages of the hydration of retarded oilwell cement

    E-print Network

    Billingham, John

    ), dicalcium silicate (C2S), tricalcium aluminate (C3A) and calcium sulphate (CaSO4). With the exception of C2S constituent of oilwell cement, tricalcium silicate (C3S), to form a calcium silicate hydrate gel (CSH in the oil industry to line oil wells. The major com- ponents of oilwell cement are tricalcium silicate (C3S

  14. c-Fos expression in ouabain-treated vascular smooth muscle cells from rat aorta: evidence for an intracellular-sodium-mediated, calcium-independent mechanism.

    PubMed

    Taurin, Sebastien; Dulin, Nickolai O; Pchejetski, Dimitri; Grygorczyk, Ryszard; Tremblay, Johanne; Hamet, Pavel; Orlov, Sergei N

    2002-09-15

    In this study, we examined the effect of Na(+)-K(+) pump inhibition on the expression of early response genes in vascular smooth muscle cells (VSMC) as possible intermediates of the massive RNA synthesis and protection against apoptosis seen in ouabain-treated VSMC in our previous experiments. Incubation of VSMC with ouabain resulted in rapid induction of c-Fos protein expression with an approximately sixfold elevation after 2 h of incubation. c-Jun expression was increased by approximately fourfold after 12 h, whereas expression of activating transcription factor 2, cAMP/Ca(2+) response element binding protein (CREB)-1 and c-Myc was not altered. Markedly augmented c-Fos expression was also observed under Na(+)-K(+) pump inhibition in potassium-depleted medium. Na(+)-K(+) pump inhibition triggered c-Fos expression via elevation of the [Na(+)](i)/[K(+)](i) ratio. This conclusion follows from experiments showing the lack of effect of ouabain on c-Fos expression in high-potassium-low-sodium medium and from the comparison of dose responses of Na(+)-K(+) pump activity, [Na(+)](i) and [K(+)](i) content and c-Fos expression to ouabain. A fourfold increment of c-Fos mRNA was revealed 30 min following addition of ouabain to the incubation medium. At this time point, treatment with ouabain resulted in an approximately fourfold elevation of [Na(+)](i) but did not affect [K(+)](i). Augmented c-Fos expression was also observed under VSMC depolarization in high-potassium medium. Increments in both c-Fos expression and (45)Ca uptake in depolarized VSMC were abolished under inhibition of L-type Ca(2+) channels with 0.1 microM nicardipine. Ouabain did not affect the free [Ca(2+)](i) or the content of exchangeable [Ca(2+)](i). Ouabain-induced c-Fos expression was also insensitive to the presence of nicardipine and [Ca(2+)](o), as well as chelators of [Ca(2+)](o) (EGTA) and [Ca(2+)](i) (BAPTA). The effect of ouabain and serum on c-Fos expression was additive. In contrast to serum, however, ouabain failed to activate the Elk-1, serum response factor, CREB and activator protein-1 transcription factors identified within the c-Fos promoter. These results suggest that Na(+)-K(+) pump inhibition triggers c-Fos expression via [Na(+)](i)-sensitive [Ca(2+)](i)-independent transcription factor(s) distinct from factors interacting with known response elements of this gene promoter. PMID:12231642

  15. Effects of postexsanguination vascular infusion of carcasses with calcium chloride or a solution of saccharides, sodium chloride, and phosphates on beef display-color stability.

    PubMed

    Hunt, M C; Schoenbeck, J J; Yancey, E J; Dikeman, M E; Loughin, T M; Addis, P B

    2003-03-01

    Hereford x Angus crossbred steers (n = 36) were stunned, exsanguinated, and infused via the carotid artery either with an aqueous solution containing 98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphates (MPSC; n = 12) or with 0.3 M CaCl2 (n = 12). The remaining 12 steers served as noninfused controls. At 48 h postmortem, the quadriceps muscles and subcutaneous fat were removed from the carcasses, frozen, and later made into ground beef (18 to 20% fat). The longissimus lumborum (LL), semimembranosus, and psoas major (PM) also were removed, vacuum packaged, aged until 14 d postmortem, and then one steak was sliced from each muscle for visual and instrumental color evaluations. The inside (ISM) and outside (OSM) portions of the SM were evaluated separately. The LL and OSM steaks from MPSC-infused carcasses had a lighter red (P < 0.05) initial appearance than steaks from the other treatments. The LL steaks from noninfused carcasses had the most (P < 0.05) uniform color; the MPSC treatment was intermediate, and the CaCl2 treatment was the most two-toned. Steaks from both infusion treatments had higher (P < 0.05) L* values for the LL, ISM, and OSM muscles compared with noninfused carcasses. In general, the LL from CaCl2-infused carcasses had lower (P < 0.05) a* values, saturation indices, and 630 nm to 580 nm reflectance values, and had larger (P < 0.05) hue angles. Infusion with MPSC increased (P < 0.05) hue angles in the LL and OSM. Display color stability was lowest (P < 0.05) for LL steaks from CaCl2-infused carcasses, whereas steaks from MPSC-infused carcasses were lighter red in initial color, but otherwise had display color stability similar to those from noninfused carcasses. No differences (P > 0.05) due to infusion were found for any color traits for the PM muscle and ground beef. Carotid artery vascular infusion of carcasses with CaCl2 resulted in undesirable meat colors, whereas the MPSC solution lightened loin and inside round color in a desirable way, but the color stability was slightly less compared to muscle from noninfused carcasses. Infusion effects were not consistent among muscles, and further research will be needed to determine what caused these differences. PMID:12661647

  16. Physical properties and self-setting mechanism of calcium phosphate cements from calcium bis-dihydrogenophosphate monohydrate and calcium oxide

    Microsoft Academic Search

    P. BOUDEVILLE; S. SERRAJ; J.-M. LELOUP; J. MARGERIT; B. PAUVERT; A. TEROL

    1999-01-01

    An apatitic calcium phosphate cement was developed from calcium bis-dihydro-genophosphate monohydrate (or monocalcium phosphate monohydrate, MCPM) and calcium oxide (CaO). The powder had a Ca\\/P molar ratio of 1.67, and the liquid was either pure water or 0.25 M–1 M sodium phosphate buffer, pH 7.4. The influence of the powder-to-liquid (P\\/L) ratio on the setting time and the mechanical strength

  17. Some properties of alginate gels derived from algal sodium alginate

    Microsoft Academic Search

    H. Kakita; H. Kamishima

    Alginic acid in soluble sodium alginate turns to insoluble gel after contact with divalent metal ions, such as calcium ions.\\u000a The sodium alginate character has an effect on the alginate gel properties. In order to prepare a suitable calcium alginate\\u000a gel for use in seawater, the effects of sodium alginate viscosity and M\\/G ratio (the ratio of D-mannuronate to L-guluronate)

  18. Some properties of alginate gels derived from algal sodium alginate

    Microsoft Academic Search

    H. Kakita; H. Kamishima

    2008-01-01

    Alginic acid in soluble sodium alginate turns to insoluble gel after contact with divalent metal ions, such as calcium ions.\\u000a The sodium alginate character has an effect on the alginate gel properties. In order to prepare a suitable calcium alginate\\u000a gel for use in seawater, the effects of sodium alginate viscosity and M\\/G ratio (the ratio of D-mannuronate to L-guluronate)

  19. Sodium Phosphate

    MedlinePLUS

    Sodium phosphate is used in adults 18 years of age or older to empty the colon (large intestine, ... clear view of the walls of the colon. Sodium phosphate is in a class of medications called saline ...

  20. Effects of Halogen Ions on Phase Equilibrium of Methane Hydrate in Porous Media

    NASA Astrophysics Data System (ADS)

    Yang, Mingjun; Song, Yongchen; Liu, Yu; Lam, Wei-Haur; Li, Qingping; Yu, Xichong

    2012-05-01

    The influences of halogen ions extracted from sodium fluoride, sodium chloride, sodium bromide, and sodium iodide and their concentrations on methane hydrate phase equilibrium conditions in porous media were investigated experimentally using an orthogonal test method at a pressure of 8 MPa. The experimental results showed that the equilibrium temperature of methane hydrate decreased when halogen ions were added. The equilibrium temperature decreased with the increase of halogen ion concentrations. The influence of the sources of the halogens ion to the methane hydrate equilibrium temperature were insensitive according to variance analysis, which could be explained by about the same mean ionic activity coefficient (a dimensionless coefficient relates the activity to a measured concentration) of sodium fluoride, sodium chloride, sodium bromide, and sodium iodide. The experimental measurements were also in close agreement with the thermodynamic model of Song et al. (J. Nat. Gas Chem. 19, 241 (2010)), in which the mechanical equilibrium of force between the interfaces in a hydrate-liquid-vapor system was considered.

  1. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. (a) Chemical...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt (PMN...

  2. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. (a) Chemical...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt (PMN...

  3. 40 CFR 721.2076 - D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. (a) Chemical...6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt (PMN...

  4. Effect of food preservatives on the hydration properties and taste behavior of amino acids: A volumetric and viscometric approach.

    PubMed

    Banipal, Tarlok S; Kaur, Navalpreet; Kaur, Amanpreet; Gupta, Mehak; Banipal, Parampaul K

    2015-08-15

    Thermodynamic and transport properties of aqueous solutions are very useful in the elucidation of solute-solvent and solute-solute interactions, which help to understand the hydration and taste behavior of solutes. The densities and viscosities of l-glycine, ?-alanine and l-leucine have been determined in water and in aqueous solutions of sodium propionate (NaP) and calcium propionate (CaP) at temperatures 298.15 and 308.15K. From these data, apparent molar volumes (V2,?), viscosity B-coefficients and corresponding transfer parameters (?trV2,?o and ?trB) have been calculated. The dB/dT values suggest that l-glycine and ?-alanine act as structure-breaker, while l-leucine acts as structure-maker both in water and in aqueous solutions of NaP and CaP. The decrease in hydration number and change in taste behavior have also been observed with increasing concentration of the cosolute. PMID:25794759

  5. Ionic modification of calcium phosphate cement viscosity. Part II: hypodermic injection and strength improvement of brushite cement.

    PubMed

    Barralet, J E; Grover, L M; Gbureck, U

    2004-05-01

    Brushite-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. However, their short setting times, low mechanical strengths and limited injectability limit broad clinical application. In this study, we showed that a significant improvement of these properties of brushite cement could be achieved by the use of sodium citrate or citric acid as setting retardants, such that workable cement pastes with a powder to liquid ratio of up to 5 could be manufactured. The cement used in this study consisted of an equimolar powder mixture of beta-tricalcium phosphate and monocalcium phosphate hydrate The use of 500 mM-1M retardant solutions as liquid phase enabled initial setting times of 8-12 min. Wet compressive strength were found to be in the range between 12-18 MPa after immersion of uncompacted cement samples in serum for 24 h. A further strength improvement to 32 MPa was obtained by compaction of the cement paste during samples preparation. This is significant because high-temperature processes cannot be used to fabricate hydrated calcium phosphate materials. Cement pastes were injectable through a hypodermic needle at a powder to liquid ratio of 3.3 g/ml when a 1M citric acid was used as liquid phase, thus enabling precise controlled delivery to small defects. PMID:14741635

  6. Hydrothermal Transformation of the Calcium Aluminum Oxide Hydrates CaAl2O4 . 10H2O and Ca2Al2O. 8H2O to Ca3Al2(OH)12 Investigated by In Situ Synchrotron X-ray Powder Diffraction

    SciTech Connect

    Jensen,T.; Christensen, A.; Hanson, J.

    2005-01-01

    The hydrothermal transformation of calcium aluminate hydrates were investigated by in situ synchrotron X-ray powder diffraction in the temperature range 25 to 170 C. This technique allowed the study of the detailed reaction mechanism and identification of intermediate phases. The material CaAl{sub 2}O{sub 4}{center_dot}10H{sub 2}O converted to Ca{sub 3}Al{sub 2}(OH){sub 12} and amorphous aluminum hydroxide. Ca{sub 2}Al{sub 2}O{sub 5}{center_dot}8H{sub 2}O transformed via the intermediate phase Ca{sub 4}Al{sub 2}O{sub 7}{center_dot}13H{sub 2}O to Ca{sub 3}Al{sub 2}(OH){sub 12} and gibbsite, Al(OH){sub 3}. The phase Ca{sub 4}Al{sub 2}O{sub 7}{center_dot}19H{sub 2}O reacted via the same intermediate phase to Ca{sub 3}Al{sub 2}(OH){sub 12} and mainly amorphous aluminum hydroxide. The powder pattern of the intermediate phase is reported.

  7. Alternative Splicing of an Insect Sodium Channel Gene Generates Pharmacologically Distinct Sodium Channels

    Microsoft Academic Search

    Jianguo Tan; Zhiqi Liu; Yoshiko Nomura; Alan L. Goldin; Ke Dong

    2002-01-01

    Alternative splicing is a major mechanism by which potassium and calcium channels increase functional diversity in animals. Extensive alternative splicing of the para sodium channel gene and developmental regulation of alternative splicing have been reported in Drosophila species. Alternative splicing has also been observed for several mammalian voltage-gated sodium channel genes. However, the functional significance of alterna- tive splicing of

  8. Final Report on the Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum

    E-print Network

    Ahmad, Sajjad

    Final Report on the Safety Assessment of Aluminum Silicate, Calcium Silicate, Magnesium Aluminum dose of Zeolite A without any adverse reaction in the eye. Calcium Silicate had no discernible effect Silicate, Magnesium Silicate, Magnesium Trisilicate, Sodium Magnesium Silicate, Zirconium Silicate

  9. Class H cement hydration at 180 deg. C and high pressure in the presence of added silica

    SciTech Connect

    Jupe, Andrew C. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States); Wilkinson, Angus P. [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States)], E-mail: angus.wilkinson@chemistry.gatech.edu; Luke, Karen [Formerly with Halliburton, now with Trican Well Services Ltd. R and D Centre, 11979-40th Street S.E., Calgary, AB T2Z 4M3 (Canada); Funkhouser, Gary P. [Halliburton, Duncan Technology Center, 2600 South 2nd Street, Duncan, OK 73536-0470 (United States)

    2008-05-15

    Under deep oil-well conditions of elevated temperature and pressure, crystalline calcium silicate hydrates are formed during Portland cement hydration. The use of silica rich mineral additives leads to the formation of crystalline hydrates with better mechanical properties than those formed without the additive. The effects of silica flour, silica fume (amorphous silica), and a natural zeolite mixture on the hydration of Class H cement slurries at 180 deg. C under externally applied pressures of 7 and 52 MPa are examined in real time using in-situ synchrotron X-ray diffraction. For some compositions examined, but not all, pressure was found to have a large effect on the kinetics of crystalline hydrate formation. The use of silica fume delayed both C{sub 3}S hydration and the formation of crystalline silicate hydrates compared to what was seen with other silica sources.

  10. Controlling factors and mechanism of reactive crystallization of calcium carbonate polymorphs from calcium hydroxide suspensions

    Microsoft Academic Search

    Mitsutaka Kitamura; Haruo Konno; Atsunari Yasui; Hirokatsu Masuoka

    2002-01-01

    The crystallization was carried out by adding the Na2CO3 solution to the Ca(OH)2 suspension, and the controlling factor and the mechanism of the crystallization of calcium carbonate polymorphs were investigated. The reaction between calcium hydroxide and sodium carbonate proceeded almost with the stoichiometric ratio when the addition rate of Na2CO3 solution was low; however, at fast addition rate calcium hydroxide

  11. New high-capacity, calcium-based sorbents, calcium silicate sorbents. Final report

    SciTech Connect

    Kenney, M.E.

    1996-02-28

    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 current year objectives include the study of sorbents made by hydrating ordinary or Type I portland cement or portland cement clinker (a cement intermediate) under carefully selected conditions. Results of this study show that an excellent portland cement sorbent can be prepared by milling cement at 120{degrees}C at 600 rpm for 15 minutes with MgO-stabilized ZrO{sub 2} beads. They also show that clinker, which is cheaper than cement can be used interchangeably with cement as a starting material. Further, it is clear that while a high surface area may be a desirable property of a good sorbent, it is not a requisite property. Among the hydration reaction variables, milling time is highly important, reaction temperature is important and stirring rate and silicate-to-H{sub 2}O ratio are moderately important. The components of hydrated cement sorbent are various combinations of C-S-H, calcium silicate hydrate:Ca(OH){sub 2};AFm. a phase in hydrated cement.

  12. Effects of postexsanguination vascular infusion of cattle with a solution of saccharides, sodium chloride, and phosphates or with calcium chloride on quality and sensory traits of steaks and ground beef.

    PubMed

    Dikeman, M E; Hunt, M C; Addist, P B; Schoenbeck, H J; Pullen, M; Katsanidis, E; Yancey, E J

    2003-01-01

    Grain-finished Hereford x Angus steers (n = 36) were assigned to one of three treatmentgroups. Immediately after jugular exsanguination, 12 steers were infused at 10% of live weight via the left carotid artery with a solution developed by MPSC, Inc. (St. Paul, MN) consisting of 98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphate blend (MPSC); 12 steers were infused at 10% of live weight with 0.30 M CaCl2 (CaCl2); and 12 steers were exsanguinated conventionally and served as noninfused controls (CON). Declines in pH for three muscles were measured. CaCl2-infused carcasses exhibited extensive muscle contraction at the time of cooler entry. Carcasses were graded at 24 h postmortem and fabricated at 48 h postmortem. Longissimus lumborum (LL), semitendinosus (ST), and quadriceps femoris (QF) muscles were removed, vacuum packaged, and stored at 2 degrees C until 14 d postmortem. Then, 2.54-cm-thick steaks were cut from the LL and ST for shear force and sensory evaluations. Ground beef was formulated from the QF to contain 20% fat. Steers infused with MPSC and CaCl2 had 4.0 and 2.3% higher dressing percentage points, respectively, than CON steers. Calcium concentrations of the LL muscle for CaCl2- and MPSC-infused carcasses, as well as the CON carcasses, were 892.0, 158.9, and 216.6 ppm, respectively. For the TB and longissimus thoracis muscles, pH decline was more rapid for CaCl2- and MPSC-infused carcasses than for CON carcasses, but there were no differences in 24-h pH. Warner-Bratzler shear force values were much higher (P < 0.05), and descriptive attribute sensory panel tenderness scores much lower (P < 0.05), for the LL from CaCl2-infused carcasses than for MPSC-infused and CON carcasses. Flavor intensity of the LL of CaCl2-infused carcasses was reduced (P < 0.05); however, overall tenderness and flavor of the ST were unaffected (P > 0.05) by CaCl2 infusion. Beef flavor identification, brown-roasted flavor, and bloody/serumy flavor were lowest and soapy/chemical flavor was highest (P < 0.05) for both freshly cooked and warmed-over LL from CaCl2-infused carcasses. There were no distinct meat quality advantages for infusing cattle with a solution of saccharides, sodium chloride, and phosphates. Infusion with 0.30 M CaCl2 increased dressing percentage, but caused severe muscle contraction early postmortem, decreased LL tenderness markedly, and reduced flavor of LL steaks and ground beef. PMID:12597386

  13. Compressibility of gas hydrates.

    PubMed

    Manakov, Andrey Yu; Likhacheva, Anna Yu; Potemkin, Vladimir A; Ogienko, Andrey G; Kurnosov, Alexander V; Ancharov, Aleksei I

    2011-09-12

    Experimental data on the pressure dependence of unit cell parameters for the gas hydrates of ethane (cubic structure I, pressure range 0-2 GPa), xenon (cubic structure I, pressure range 0-1.5 GPa) and the double hydrate of tetrahydrofuran+xenon (cubic structure II, pressure range 0-3 GPa) are presented. Approximation of the data using the cubic Birch-Murnaghan equation, P=1.5B(0)[(V(0)/V)(7/3)-(V(0)/V)(5/3)], gave the following results: for ethane hydrate V(0)=1781 Å(3) , B(0)=11.2 GPa; for xenon hydrate V(0)=1726 Å(3) , B(0)=9.3 GPa; for the double hydrate of tetrahydrofuran+xenon V(0)=5323 Å(3) , B(0)=8.8 GPa. In the last case, the approximation was performed within the pressure range 0-1.5 GPa; it is impossible to describe the results within a broader pressure range using the cubic Birch-Murnaghan equation. At the maximum pressure of the existence of the double hydrate of tetrahydrofuran+xenon (3.1 GPa), the unit cell volume was 86% of the unit cell volume at zero pressure. Analysis of the experimental data obtained by us and data available from the literature showed that 1) the bulk modulus of gas hydrates with classical polyhedral structures, in most cases, are close to each other and 2) the bulk modulus is mainly determined by the elasticity of the hydrogen-bonded water framework. Variable filling of the cavities with guest molecules also has a substantial effect on the bulk modulus. On the basis of the obtained results, we concluded that the bulk modulus of gas hydrates with classical polyhedral structures and existing at pressures up to 1.5 GPa was equal to (9±2) GPa. In cases when data on the equations of state for the hydrates were unavailable, the indicated values may be recommended as the most probable ones. PMID:21717564

  14. Improved evidence for the existence of an intermediate phase during hydration of tricalcium silicate

    SciTech Connect

    Bellmann, Frank, E-mail: frank.bellmann@uni-weimar.d [Institute for Building Materials Science, Bauhaus University Weimar, 99423 Weimar (Germany); Damidot, Denis [Ecole des Mines de Douai, Civil and Environmental Engineering Department, 941 rue Charles Bourseul, BP 10838, 59508 Doua cedexi (France); Moeser, Bernd [Institute for Building Materials Science, Bauhaus University Weimar, 99423 Weimar (Germany); Skibsted, Jorgen [Instrument Center for Solid-State NMR Spectroscopy and Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University DK-8000 Aarhus C (Denmark)

    2010-06-15

    Tricalcium silicate (Ca{sub 3}SiO{sub 5}) with a very small particle size of approximately 50 nm has been prepared and hydrated for a very short time (5 min) by two different modes in a paste experiment, using a water/solid-ratio of 1.20, and by hydration as a suspension employing a water/solid-ratio of 4000. A phase containing uncondensed silicate monomers close to hydrogen atoms (either hydroxyl groups or water molecules) was formed in both experiments. This phase is distinct from anhydrous tricalcium silicate and from the calcium-silicate-hydrate (C-S-H) phase, commonly identified as the hydration product of tricalcium silicate. In the paste experiment, approximately 79% of silicon atoms were present in the hydrated phase containing silicate monomers as determined from {sup 29}Sileft brace{sup 1}Hright brace CP/MAS NMR. This result is used to show that the hydrated silicate monomers are part of a separate phase and that they cannot be attributed to a hydroxylated surface of tricalcium silicate after contact with water. The phase containing hydrated silicate monomers is metastable with respect to the C-S-H phase since it transforms into the latter in a half saturated calcium hydroxide solution. These data is used to emphasize that the hydration of tricalcium silicate proceeds in two consecutive steps. In the first reaction, an intermediate phase containing hydrated silicate monomers is formed which is subsequently transformed into C-S-H as the final hydration product in the second step. The introduction of an intermediate phase in calculations of the early hydration of tricalcium silicate can explain the presence of the induction period. It is shown that heterogeneous nucleation on appropriate crystal surfaces is able to reduce the length of the induction period and thus to accelerate the reaction of tricalcium silicate with water.

  15. Serum electrolyte concentrations and hydration status are not associated with exercise associated muscle cramping (EAMC) in distance runners

    PubMed Central

    Schwellnus, M; Nicol, J; Laubscher, R; Noakes, T

    2004-01-01

    Objectives: To determine whether acute exercise associated muscle cramping (EAMC) in distance runners is related to changes in serum electrolyte concentrations and hydration status. Methods: A cohort of 72 runners participating in an ultra-distance road race was followed up for the development of EAMC. All subjects were weighed before and immediately after the race. Blood samples were taken before the race, immediately after the race, and 60 minutes after the race. Blood samples were analysed for glucose, protein, sodium, potassium, calcium, and magnesium concentrations, as well as serum osmolality, haemoglobin, and packed cell volume. Runners who suffered from acute EAMC during the race formed the cramp group (cramp, n = 21), while runners with no history of EAMC during the race formed the control group (control, n = 22). Results: There were no significant differences between the two groups for pre-race or post-race body weight, per cent change in body weight, blood volume, plasma volume, or red cell volume. The immediate post-race serum sodium concentration was significantly lower (p = 0.004) in the cramp group (mean (SD), 139.8 (3.1) mmol/l) than in the control group (142.3 (2.1) mmol/l). The immediate post-race serum magnesium concentration was significantly higher (p = 0.03) in the cramp group (0.73 (0.06) mmol/l) than in the control group (0.67 (0.08) mmol/l). Conclusions: There are no clinically significant alterations in serum electrolyte concentrations and there is no alteration in hydration status in runners with EAMC participating in an ultra-distance race. PMID:15273192

  16. HYDRATE CORE DRILLING TESTS

    SciTech Connect

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate formation comprised of coarse, large-grain sand in ice. Results with this core showed that the viscosity of the drilling fluid must also be carefully controlled. When coarse sand was being cored, the core barrel became stuck because the drilling fluid was not viscous enough to completely remove the large grains of sand. These tests were very valuable to the project by showing the difficulties in coring permafrost or hydrates in a laboratory environment (as opposed to a field environment where drilling costs are much higher and the potential loss of equipment greater). Among the conclusions reached from these simulated hydrate coring tests are the following: Frozen hydrate core samples can be recovered successfully; A spring-finger core catcher works best for catching hydrate cores; Drilling fluid can erode the core and reduces its diameter, making it more difficult to capture the core; Mud must be designed with proper viscosity to lift larger cuttings; and The bottom 6 inches of core may need to be drilled dry to capture the core successfully.

  17. Sodium Bicarbonate

    MedlinePLUS

    Sodium bicarbonate comes as a tablet and powder to take by mouth. Sodium bicarbonate is taken one to four times a day, depending on the reason you ... flecainide (Tambocor), iron, ketoconazole (Nizoral), lithium (Eskalith, ... Urex), methotrexate, quinidine, sulfa-containing antibiotics, tetracycline ( ...

  18. Sodium Test

    MedlinePLUS

    ... irrationally, and coma or convulsions if the sodium level rises to extremely high concentrations. In rare cases, hypernatremia may be due to Cushing syndrome or a condition caused by too little ADH ... association with blood levels. The body normally excretes excess sodium, so the ...

  19. Impact of admixtures on the hydration kinetics of Portland cement

    SciTech Connect

    Cheung, J., E-mail: Josephine.H.Cheung@grace.com [W.R. Grace, 62 Whittemore Avenue, Cambridge MA 02140 (United States); Jeknavorian, A. [W.R. Grace, 62 Whittemore Avenue, Cambridge MA 02140 (United States); Roberts, L. [Roberts Consulting Group LLC, 44 Windsor Avenue, Acton MA 01720 (United States); Silva, D. [W.R. Grace, 62 Whittemore Avenue, Cambridge MA 02140 (United States)

    2011-12-15

    Most concrete produced today includes either chemical additions to the cement, chemical admixtures in the concrete, or both. These chemicals alter a number of properties of cementitious systems, including hydration behavior, and it has been long understood by practitioners that these systems can differ widely in response to such chemicals. In this paper the impact on hydration of several classes of chemicals is reviewed with an emphasis on the current understanding of interactions with cement chemistry. These include setting retarders, accelerators, and water reducing dispersants. The ability of the chemicals to alter the aluminate-sulfate balance of cementitious systems is discussed with a focus on the impact on silicate hydration. As a key example of this complex interaction, unusual behavior sometimes observed in systems containing high calcium fly ash is highlighted.

  20. Degradation behavior of high surface area calcium hydroxide sorbent for SO 2 removal

    Microsoft Academic Search

    Hyun-Gyoo Shin; Hwan Kim; Taimin Noh; Dowan Kim; Yong-Nam Kim

    2011-01-01

    The degradation behavior of a calcium hydroxide sorbent for SO2 removal was investigated in terms of microstructure and crystal phase change. Hydrated lime sorbents with a high surface area were prepared by hydration of Diethylene glycol-coated quicklime. A durability test for sorbents was carried out in a consistent chamber condition at a temperature of 50°C and a humidity level of

  1. Ethyl­enedi­ammonium sodium tetra­kis­[bis­(ethyl­enedi­amine-?2 N,N?)(oxalato-?2 O 1,O 2)cobalt(III)] [penta­hydrogen di(phosphato­octa­deca­tungstate)] tetra­deca­hydrate

    PubMed Central

    Zhang, Shuzhuo; Wang, Jing; Xu, Yun

    2013-01-01

    The title compound, Na(C2H10N2)[Co(C2O4)(C2H8N2)2]4[H5(P2W18O62)2]·14H2O, prepared under hydro­thermal conditions, consists of two Dawson-type [P2W18O62]6? anions, four isolated [Co(en)2(ox)]+ cations (en = ethyl­enedi­amine and ox = oxalate), one Na+ cation, one [H2en]2+ cation, and a number of ordered (14) and disordered solvent water mol­ecules. The [P2W18O62]6? polyoxidometalate anion has site symmetry 1 and contains two structurally distinct types of W atoms: viz. six W atoms on vertical pseudo-mirror planes grouped in two sets of three, and 12 equatorial W atoms that do not lie in the pseudo-mirror planes grouped in two sets of six. In each [Co(en)2(ox)]+ cation, the CoIII ion is coordinated by four N atoms from two en ligands and two O atoms from the ox ligands, completing a distorted octa­hedral structure. The sodium cation lies on an inversion centre and additionally links the complex cations and anions. In the crystal, the various units are linked by N—H?O and O—H?O hydrogen bonds, which together with C—H?O hydrogen bonds form a three-dimensional structure. The contribution of a region of disordered electron density, possibly highly disordered solvent water mol­ecules, to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009 ?). Acta Cryst. D65, 148–155]. To equilibrate the charges five H+ ions have been added to the polyoxidometalate. These H+ ions and the disordered solvent contribution were not included in the reported mol­ecular weight and density. PMID:24454036

  2. Ethyl-enedi-ammonium sodium tetra-kis-[bis-(ethyl-enedi-amine-?(2) N,N')(oxalato-?(2) O (1),O (2))cobalt(III)] [penta-hydrogen di(phosphato-octa-deca-tungstate)] tetra-deca-hydrate.

    PubMed

    Zhang, Shuzhuo; Wang, Jing; Xu, Yun

    2013-10-16

    The title compound, Na(C2H10N2)[Co(C2O4)(C2H8N2)2]4[H5(P2W18O62)2]·14H2O, prepared under hydro-thermal conditions, consists of two Dawson-type [P2W18O62](6-) anions, four isolated [Co(en)2(ox)](+) cations (en = ethyl-enedi-amine and ox = oxalate), one Na(+) cation, one [H2en](2+) cation, and a number of ordered (14) and disordered solvent water mol-ecules. The [P2W18O62](6-) polyoxidometalate anion has site symmetry 1 and contains two structurally distinct types of W atoms: viz. six W atoms on vertical pseudo-mirror planes grouped in two sets of three, and 12 equatorial W atoms that do not lie in the pseudo-mirror planes grouped in two sets of six. In each [Co(en)2(ox)](+) cation, the Co(III) ion is coordinated by four N atoms from two en ligands and two O atoms from the ox ligands, completing a distorted octa-hedral structure. The sodium cation lies on an inversion centre and additionally links the complex cations and anions. In the crystal, the various units are linked by N-H?O and O-H?O hydrogen bonds, which together with C-H?O hydrogen bonds form a three-dimensional structure. The contribution of a region of disordered electron density, possibly highly disordered solvent water mol-ecules, to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009 ?). Acta Cryst. D65, 148-155]. To equilibrate the charges five H(+) ions have been added to the polyoxidometalate. These H(+) ions and the disordered solvent contribution were not included in the reported mol-ecular weight and density. PMID:24454036

  3. Optimizing the calcium content of a copolymer acrylamide gel matrix for dark-grown seedlings

    NASA Technical Reports Server (NTRS)

    Myers, P. N.; Mitchell, C. A.

    1998-01-01

    A copolymer acrylamide acrylate gel was investigated as the sole root matrix for dark-grown seedlings of soybean (Glycine max Merr. 'Century 84'). Increasing Ca2+ in the hydrating solution of the hydrogel from 1 to 10 mM decreased its water-holding capacity from 97 to 46 mL g-1, yet water potential of the medium remained high, sufficient for normal plant growth at all Ca2+ concentrations tested. Elongation rate of dark-grown soybean seedlings over a 54-hour period was 0.9, 1.5, and 1.8 mm h-1 with 1.0, 2.5, or 5.0 mM Ca2+, respectively, but did not increase with further increases in Ca2+ concentration. Further study revealed that Na+ was released from the hydrogel medium and was taken up by the seedlings as Ca2+ increased in the medium. In dry hypocotyl tissue, sodium content correlated negatively with calcium content. Despite the presence of Na+ in the hydrogel, seedling growth was normal when adequate Ca2+ was added in the hydrating solution. Acrylamide hydrogels hold good potential as a sole growth matrix for short-term experiments with dark-grown seedlings without irrigation.

  4. Interactions of fully formulated epoxy with model cement hydrates

    Microsoft Academic Search

    Fatma Djouani; Mohamed M. Chehimi; Karim Benzarti

    2012-01-01

    The surface energy of cement paste components (calcium silicate hydrate [C-S-H], ettringite and portlandite) before and after treatment with an organic coating has been characterised by X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography at 35?°C using n-alkanes, 1-alkene, chloroform, tetrahydrofuran, diethyl ether and CCl4 molecular probes. Complementary investigations on the interfacial chemistry were also conducted by Fourier transform infrared

  5. Aluminum Sulfate 18 Hydrate

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) of the chemical, aluminum sulfate 18 hydrate, is presented. The profile lists physical and harmful properties, exposure limits, reactivity risks, and symptoms of major exposure for the benefit of teachers and students using the chemical in the laboratory.

  6. Standard enthalpies of formation of francium hydroxide hydrates

    SciTech Connect

    Burylev, B.P.

    1995-03-01

    Available experimental data on standard enthalpies of formation of alkali metal hydroxide hydrates have been summarized. Using equations derived, the authors have calculated previously unknown enthalpies of formation of some lithium, sodium, potassium, rubidium, and cesium hydroxide hydrates. Taking into account the contribution of water to the enthalpies of formation of monohydrates, the authors have estimated the enthalpies of formation of francium hydroxide hydrates FrOH{center_dot}H{sub 2}O, FrOH{center_dot}2H{sub 2}O, and FrOH{center_dot}3H{sub 2}O (-745.8, -1085.8, and -1515.8 kJ mol{sup -1}, respectively).

  7. TRPM8 and Na v 1.8 sodium channels are required for transthyretin-induced calcium influx in growth cones of small-diameter TrkA-positive sensory neurons

    Microsoft Academic Search

    Robert J Gasperini; Xu Hou; Helena Parkington; Harry Coleman; David W Klaver; Adele J Vincent; Lisa C Foa; David H Small

    2011-01-01

    Background  Familial amyloidotic polyneuropathy (FAP) is a peripheral neuropathy caused by the extracellular accumulation and deposition\\u000a of insoluble transthyretin (TTR) aggregates. However the molecular mechanism that underlies TTR toxicity in peripheral nerves\\u000a is unclear. Previous studies have suggested that amyloidogenic proteins can aggregate into oligomers which disrupt intracellular\\u000a calcium homeostasis by increasing the permeability of the plasma membrane to extracellular calcium.

  8. Characteristics of a Hydrated, Alginate-Based Delivery System for Cultivation of the Button Mushroom

    PubMed Central

    Romaine, C. P.; Schlagnhaufer, B.

    1992-01-01

    The production of the button mushroom Agaricus bisporus with mycelium-colonized alginate pellets as an inoculant of the growing medium was investigated. Pellets having an irregular surface and porous internal structure were prepared by complexing a mixture of 1% sodium alginate, 2 to 6% vermiculite, 2% hygramer, and various concentrations of Nutrisoy (soy protein) with calcium chloride. The porous structure allowed the pellets to be formed septically and then inoculated and colonized with the fungus following sterilization. By using an enzyme-linked immunosorbent assay (ELISA) to estimate fungal biomass, the matrix components of the pellet were found to be of no nutritive value to A. bisporus. Pellets amended with Nutrisoy at a concentration of 0.5 to 8% supported extensive mycelial growth, as determined by significantly increased ELISA values, with a concentration of 4% being optimal and higher concentrations proving inhibitory. The addition of hydrated, mycelium-invaded pellets to the compost or casing layer supported the thorough colonization of the growing substrate and culminated in the formation of mushrooms that showed normal development and typical morphology. Yields and sizes of mushrooms were comparable from composts seeded with either colonized pellets or cereal grain spawn. Similarly, amending the casing layer with pelletized-mycelium-colonized compost resulted in a 2- to 3-day-earlier and more-synchronous emergence of mushrooms than with untreated casing. This technology shows the greatest potential as a pathogen-free inoculant of the casing layer in the commercial cultivation of mushrooms. Images PMID:16348774

  9. Growth of nanofibrous barium carbonate on calcium carbonate seeds

    NASA Astrophysics Data System (ADS)

    Homeijer, Sara J.; Olszta, Matthew J.; Barrett, Richard A.; Gower, Laurie B.

    2008-05-01

    Fibrous barium carbonate (BaCO 3/witherite) crystals 50-100 nm in diameter and several microns in length were grown on calcium carbonate (CaCO 3) seeds at temperatures as low as 4 °C. The BaCO 3 fibers were deposited onto calcite rhombs or CaCO 3 films using the polymer-induced liquid-precursor (PILP) process, which was induced with the sodium salt of polyacrylic acid (PAA). The structure and morphology of the resultant fibers were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and polarized light microscopy (PLM). Fibers were successfully grown on calcite seeds of various morphologies, with a range of barium concentrations, and PAA molecular weight and concentration. Two categories of fibers were grown: straight and twisted. Both types of fibers displayed single-crystalline SAED diffraction patterns, but after examining high-resolution TEM lattice images, it was revealed that the fibers were in fact made up of nanocrystalline domains. We postulate that these nanocrystalline domains are well aligned due to a singular nucleation event (i.e., each fiber propagates from a single nucleation event on the seed crystal) with the nanocrystalline domains resulting from stresses caused by dehydration during crystallization of the highly hydrated precursor phase. These BaCO 3 fibers grown on calcite substrates further illustrate the robustness and non-specificity of the PILP process.

  10. Modified calcium silicates as active rubber fillers

    Microsoft Academic Search

    Andrzej Krysztafkiewicz

    1987-01-01

    The physicochemical characteristics of calcium silicates obtained from the reaction of sodium metasilicate solution with calcium\\u000a nitrate are given. Further, studies of the modification of the silicate surface with silane and titanate coupling agents are\\u000a presented. By wettability measurements and an analysis of the chemically adsorbed carbon arising from the coupling agents,\\u000a the degree of modification of these surfaces was

  11. 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

  12. 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

  13. Calcium pyrophosphate arthritis (Pseudogout)

    MedlinePLUS

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  14. Calcium carbonate overdose

    MedlinePLUS

    Tums overdose; Calcium overdose ... Calcium ... Products containing calcium carbonate, including Certain antacids (Tums, Chooz) Certain mineral supplements Certain hand lotions Certain vitamin and mineral supplements Note: ...

  15. Nutrition, Hydration & Health

    NSDL National Science Digital Library

    2010-01-01

    The following resource is a NFL sponsored, National Science Foundation funded program intended to teach students about scientific concepts by using the popular sport of Football. Each lesson is accompanied by an informative and fast paced video. In this lesson, athletic trainers from the Pittsburgh Steelers explain what NFL players must do to stay hydrated and replenish the essential nutrients needed to maintain good health during rigorous practices.

  16. Hydration-dependent dynamic crossover phenomenon in protein hydration water.

    PubMed

    Wang, Zhe; Fratini, Emiliano; Li, Mingda; Le, Peisi; Mamontov, Eugene; Baglioni, Piero; Chen, Sow-Hsin

    2014-10-01

    The characteristic relaxation time ? of protein hydration water exhibits a strong hydration level h dependence. The dynamic crossover is observed when h is higher than the monolayer hydration level hc=0.2-0.25 and becomes more visible as h increases. When h is lower than hc, ? only exhibits Arrhenius behavior in the measured temperature range. The activation energy of the Arrhenius behavior is insensitive to h, indicating a local-like motion. Moreover, the h dependence of the crossover temperature shows that the protein dynamic transition is not directly or solely induced by the dynamic crossover in the hydration water. PMID:25375521

  17. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  18. Sodium hydroxide ions in the stratosphere

    Microsoft Academic Search

    Eldon E. Ferguson

    1978-01-01

    It is suggested that nonproton hydrate ions observed at 37 km by Arnold, Boehringer, and Henschen are protonated sodium hydroxide cluster ions of the form NaOH2(+)(H2O)n(NaOH)m. It is also suggested that n ranges from 0 to 4 while m ranges from 0 to 2. Since the NaOH believed to be formed from NaO, has a very large proton affinity, protons

  19. Ris-R-1143(EN) Modelling Calcium Carbonate Deposition

    E-print Network

    Risø-R-1143(EN) CRACK2 - Modelling Calcium Carbonate Deposition from Bicarbonate Solution in Cracks of bicarbonate solution in a crack connecting the ends of a row of such columns. The cementitious material is simulated as calcium hydroxide mixed with inert material but with sodium hydroxide dissolved in the pore

  20. Gas hydrate cool storage system

    DOEpatents

    Ternes, M.P.; Kedl, R.J.

    1984-09-12

    The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

  1. Activation Energies of High-Volume Fly Ash Ternary Blends: Hydration and Dale P. Bentz

    E-print Network

    Bentz, Dale P.

    of the fly ash with a fine calcium carbonate powder. In addition to accelerating and amplifying hydration cement (OPC) concretes, more sustainable mixtures containing high volumes of fly ash (HVFA), for example sizes of 1 µm and 17 µm, replacing 10 % by volume of the cement in an OPC mixture, indicates

  2. STRUCTURAL CHANGES DURING THE DECOMPOSITION OF CALCIUM HYDROXIDE

    EPA Science Inventory

    The paper discusses the production of calcium hydroxides with surface areas of 6-74 sq m/g, in an attempt to develop more reactive sorbents for SO2 capture during furnace injection. It was found that adding alcohol to the water of hydration yielded hydroxides with surface areas u...

  3. A combined QXRD/TG method to quantify the phase composition of hydrated Portland cements

    SciTech Connect

    Soin, Alexander V.; Catalan, Lionel J.J. [Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1 (Canada)] [Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1 (Canada); Kinrade, Stephen D., E-mail: stephen.kinrade@lakeheadu.ca [Department of Chemistry, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario P7B 5E1 (Canada)

    2013-06-15

    A new method is reported for quantifying the mineral phases in hydrated cement pastes that is based on a combination of quantitative X-ray diffractometry (QXRD) and thermogravimetry (TG). It differs from previous methods in that it gives a precise measure of the amorphous phase content without relying on an assumed stoichiometric relationship between the principal hydration products, calcium hydroxide (CH) and calcium silicate hydrate (C–S–H). The method was successfully applied to gray and white ordinary Portland cements (GOPC and WOPC, respectively) that were cured for up to 56 days. Phase distributions determined by QXRD/TG closely matched those from gray-level analysis of backscattered scanning electron microscope (BSEM) images, whereas elemental compositions obtained for the amorphous phase by QXRD/TG agreed well with those measured by quantitative energy dispersive X-ray spectroscopy (EDS)

  4. Project Calcium

    SciTech Connect

    Hurley, J.P.; Benson, S.A.; Erickson, T.A.; Allan, S.E.; Bieber, J.

    1992-09-01

    Fouling problems in utility boilers have been classified into two principal types: high-temperature and low-temperature fouling. A multiclient-sponsored program was initiated at the Energy and Environmental Research Center (EERC) to better understand the causes of low-temperature fouling when burning high-calcium western US coals. The goals of Project Calcium were to define the low-temperature deposition problem, identify the calcium-based components that are responsible for the formation of the deposits, develop ways to predict their formation, and identify possible methods to mitigate the formation of these deposits. To achieve the goals of Project Calcium, detailed sampling of utility boilers and laboratory-scale studies coupled with state-of-the-art methods to determine the inorganic components in coals and coal ash-derived materials were conducted. Boiler Sampling was also performed. The work involved sampling coal, entrained ash, deposits and slags from five full-scale utility boilers combined with detailed advanced characterization of the materials. The results of this work aided in identifying the key phenomena to focus the laboratory studies and in model verification. Field testing was conducted at three utilities.

  5. Hydration of pectic polysaccharides.

    PubMed

    Ryden, P; MacDougall, A J; Tibbits, C W; Ring, S G

    2000-11-01

    The hydration and swelling of pectic polysaccharides was examined at different pHs and ionic strengths as a function of osmotic stress. For weakly charged pectic polysaccharides at low concentrations of a monovalent salt (20 mM), the main driving force for swelling originates from a polyelectrolyte effect due to the translational entropy of ions within the film. Swelling is reduced at higher salt concentrations and lower pHs. Polyelectrolyte collapse and minimal swelling is observed for more highly charged pectic polysaccharides. Replacement of the Na(+) counterion with Ca(2+) results in minimal swelling and the formation of network structures even for the weakly charged pectic polysaccharides. PMID:10951326

  6. Removal of phosphate from greenhouse wastewater using hydrated lime.

    PubMed

    Dunets, C Siobhan; Zheng, Youbin

    2014-01-01

    Phosphate (P) contamination in nutrient-laden wastewater is currently a major topic of discussion in the North American greenhouse industry. Precipitation of P as calcium phosphate minerals using hydrated lime could provide a simple, inexpensive method for retrieval. A combination of batch experiments and chemical equilibrium modelling was used to confirm the viability of this P removal method and determine lime addition rates and pH requirements for greenhouse wastewater of varying nutrient compositions. Lime: P ratio (molar ratio of CaMg(OH)?: PO??P) provided a consistent parameter for estimating lime addition requirements regardless of initial P concentration, with a ratio of 1.5 providing around 99% removal of dissolved P. Optimal P removal occurred when lime addition increased the pH from 8.6 to 9.0, suggesting that pH monitoring during the P removal process could provide a simple method for ensuring consistent adherence to P removal standards. A Visual MINTEQ model, validated using experimental data, provided a means of predicting lime addition and pH requirements as influenced by changes in other parameters of the lime-wastewater system (e.g. calcium concentration, temperature, and initial wastewater pH). Hydrated lime addition did not contribute to the removal of macronutrient elements such as nitrate and ammonium, but did decrease the concentration of some micronutrients. This study provides basic guidance for greenhouse operators to use hydrated lime for phosphate removal from greenhouse wastewater. PMID:25176490

  7. Properties and hydration of blended cements with steelmaking slag

    SciTech Connect

    Kourounis, S. [National Technical University of Athens, School of Chemical Engineering, Laboratory of Analytical and Inorganic Chemistry, 9 Heroon Polytechniou St, 15773 Athens (Greece); Tsivilis, S. [National Technical University of Athens, School of Chemical Engineering, Laboratory of Analytical and Inorganic Chemistry, 9 Heroon Polytechniou St, 15773 Athens (Greece)]. E-mail: stsiv@central.ntua.gr; Tsakiridis, P.E. [National Technical University of Athens, School of Mining and Metallurgical Engineering, Laboratory of Physical Metallurgy, 9 Heroon Polytechniou St, 15780 Athens (Greece); Papadimitriou, G.D. [National Technical University of Athens, School of Mining and Metallurgical Engineering, Laboratory of Physical Metallurgy, 9 Heroon Polytechniou St, 15780 Athens (Greece); Tsibouki, Z. [Hellenic Cement Research Center Ltd, Heracles Group, 15 K. Pateli, 14123, Lykovrissi, Athens (Greece)

    2007-06-15

    The present research study investigates the properties and hydration of blended cements with steelmaking slag, a by-product of the conversion process of iron to steel. For this purpose, a reference sample and three cements containing up to 45% w/w steel slag were tested. The steel slag fraction used was the '0-5 mm', due to its high content in calcium silicate phases. Initial and final setting time, standard consistency, flow of normal mortar, autoclave expansion and compressive strength at 2, 7, 28 and 90 days were measured. The hydrated products were identified by X-ray diffraction while the non-evaporable water was determined by TGA. The microstructure of the hardened cement pastes and their morphological characteristics were examined by scanning electron microscopy. It is concluded that slag can be used in the production of composite cements of the strength classes 42.5 and 32.5 of EN 197-1. In addition, the slag cements present satisfactory physical properties. The steel slag slows down the hydration of the blended cements, due to the morphology of contained C{sub 2}S and its low content in calcium silicates.

  8. Physicochemical characterization of calcium strontium tartrate crystals

    Microsoft Academic Search

    K. Suryanarayana; S. M. Dharmaprakash

    1997-01-01

    Mixed single crystals of calcium strontium tartrate (CST) of high optical quality and morphological perfection have been grown from light irradiated sodium meta silicate gel medium at ambient temperature. The results obtained on characterization of CST crystals using EDX, chemical analysis, X-ray diffraction and infra-red spectral techniques are reported. A thermogravimetric study is carried out in order to study the

  9. Test Your Sodium Smarts

    MedlinePLUS

    ... You may be surprised to learn how much sodium is in many foods. Sodium, including sodium chloride ... foods with little or no salt. Test your sodium smarts by answering these 10 questions about which ...

  10. Observation directe de la croissance d'hydrosilicate de calcium sur des surfaces d'alité et de silice par microscopie à force atomique

    NASA Astrophysics Data System (ADS)

    Gauffinet, Sandrine; Finot, Éric; Lesniewska, Eric; Nonat, André

    1998-08-01

    Direct observation of the growth of calcium silicate hydrates, the tricalcium silicate hydration products, at the solid-solution interface were performed by atomic force microscopy. The covering of the surface of alite or silica by a three-dimensional oriented aggregation of nano particles of calcium silicate hydrate is always observed whatever the sample. All observations and quantifications made on calcium silicate growth at the submicronic level are in agreement with the data deduced from the study of the system evolution at the macroscopic level.

  11. Mallik Gas Hydrates Test Well

    USGS Multimedia Gallery

    A test-well for collecting gas hydrates in Mallik, Canada. Gas hydrates are naturally-occurring “ice-like” combinations of natural gas and water that have the potential to provide an immense resource of natural gas from the world’s oceans and polar regions....

  12. Ductile flow of methane hydrate

    USGS Publications Warehouse

    Durham, W.B.; Stern, L.A.; Kirby, S.H.

    2003-01-01

    Compressional creep tests (i.e., constant applied stress) conducted on pure, polycrystalline methane hydrate over the temperature range 260-287 K and confining pressures of 50-100 MPa show this material to be extraordinarily strong compared to other icy compounds. The contrast with hexagonal water ice, sometimes used as a proxy for gas hydrate properties, is impressive: over the thermal range where both are solid, methane hydrate is as much as 40 times stronger than ice at a given strain rate. The specific mechanical response of naturally occurring methane hydrate in sediments to environmental changes is expected to be dependent on the distribution of the hydrate phase within the formation - whether arranged structurally between and (or) cementing sediments grains versus passively in pore space within a sediment framework. If hydrate is in the former mode, the very high strength of methane hydrate implies a significantly greater strain-energy release upon decomposition and subsequent failure of hydrate-cemented formations than previously expected.

  13. Original article Availability of calcium from skim milk, calcium sulfate

    E-print Network

    Paris-Sud XI, Université de

    Original article Availability of calcium from skim milk, calcium sulfate and calcium carbonate; accepted 19 November 1999) Abstract --Dairy products provide abundant, accessible calcium for humans, while some calcium sulfate-rich mineral waters could provide appreciable amounts of calcium

  14. Fundamental mechanisms for polycarboxylate intercalation into C 3A hydrate phases and the role of sulfate present in cement

    Microsoft Academic Search

    Johann Plank; Dai Zhimin; Helena Keller; Friedrich v. Hössle; Wolfgang Seidl

    2010-01-01

    The fundamental reactions leading to the intercalation of polycarboxylate (PC) superplasticizers into calcium aluminum hydrates were studied by hydration of pure C3A in the presence of PC at 75 °C. It was found that the amount of dissolved sulfate present in cement pore solution determines whether organo-mineral phases are formed or not. In the absence of sulfate, PCs easily intercalate during

  15. Individual and combined effects of chloride, sulfate, and magnesium ions on hydrated Portland-cement paste

    SciTech Connect

    Poole, T.S.; Wakeley, L.D.; Young, C.L. [Army Engineer Waterways Experiment Station, Vicksburg, MS (United States). Structures Lab.

    1994-03-01

    Ground water with a high concentration of magnesium ion is known to cause deterioration to portland cement concretes. A proposed mechanism for this deterioration process published previously involves an approximate 1:1 replacement of Ca ions by Mg ions in the crystalline phases of hydrated cement. The current study was undertaken to determine which ions, among magnesium, chloride, and sulfate, cause deterioration; whether their deleterious action is individual or interdependent; and to relate this mechanism of deterioration to the outlook for a 100-yr service life of concretes used in mass placements at the Waste Isolation Pilot Plant. Loss of Ca ion by cement pastes was found to be strongly related to the concentration of Mg ion in simulated ground-water solutions in which the paste samples were aged. This was true of both salt- containing and conventional cement pastes. No other ion in the solutions exerted a strong effect on Ca loss. Ca ion left first from calcium hydroxide in the pastes, depleting all calcium hydroxide by 60 days. Some calcium silicate hydrate remained even after 90 days in the solutions with the highest concentration of Mg ion, while the paste samples deteriorated noticeably. The results indicated a mechanism that involves dissolution of Ca phases and transport of Ca ions to the surface of the sample, followed by formation of Mg-bearing phases at this reaction surface rather than directly by substitution within the microstructure of hydrated cement. Given that calcium hydroxide and calcium silicate hydrate are the principal strength-giving phases of hydrated cement, this mechanism indicates the likelihood of significant loss of integrity of a concrete exposed to Mg-bearing ground water at the WIPP. The rate of deterioration ultimately will depend on Mg-ion concentration, the microstructure materials of the concrete exposed to that groundwater, and the availability of brine.

  16. Calcium and bone disease

    PubMed Central

    Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

    2013-01-01

    Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium. PMID:21674636

  17. Molecular simulation study of hydrated Na-rectorite.

    PubMed

    Zhou, Jinhong; Boek, Edo S; Zhu, Jianxi; Lu, Xiancai; Sprik, Michiel; He, Hongping

    2015-02-17

    The swelling behavior of clay minerals is an important issue in industrial processes and environmental applications. Mixed-layer clay minerals containing a smectite fraction, such as rectorite, are neglected even though they could swell and exist in nature widely. The hydration of rectorite has not been well comprehended even though they are meaningful to mineralogy and industry. This study combines molecular dynamics (MD) and Monte Carlo (MC) simulations to disclose the swelling behavior of rectorite and compare with montmorillonite. From grand canonical Monte Carlo (GCMC) and MD simulations, we obtain swelling curves and swelling free-energy curves of rectorite with a relative humidity of 100%. With the comparisons of swelling free-energy minima, we find that the bilayer hydrate of Na-rectorite is more thermodynamically stable than the monolayer hydrate, which is similar to Na-montmorillonite. However, the interlayer sodium ions in rectorite show an asymmetrical distribution quite different from the symmetrical distribution in montmorillonite. Because of unequal layer charges between the smectite part and illite part of retorite, sodium ions prefer to distribute close to the illite part surface. PMID:25625308

  18. Hypercalcemic crisis induced by calcium carbonate

    PubMed Central

    Singh, Ashutosh; Ashraf, Ambika

    2012-01-01

    We report a rare case of drug-induced hypercalcemic crisis in an elderly male resulting from calcium-containing supplements facilitated by thiazide diuretic and angiotensin-converting enzyme inhibitor. A 61-year-old male presented with hypercalcemic crisis along with renal insufficiency and metabolic alkalosis, mimicking the ‘calcium-alkali syndrome’. The patient responded to aggressive intravenous hydration along with emergent hemodialysis and salmon calcitonin. He did not have hyperparathyroidism or malignancy. History revealed an average daily intake of only 1200 mg of calcium carbonate along with vitamin D 1000 U/day over an extended period of time. The patient completely recovered in 3 days and had normal serum calcium, parathyroid hormone and phosphorous level at 3-month follow-up. The case highlights the life-threatening perils of indiscriminate and often excessive intake of calcium-containing supplements in an appropriate clinical setting. We also briefly discuss the epidemiology, clinical and laboratory features along with the recent advances in the understanding of the pathophysiology of calcium-alkali syndrome.

  19. A new hydrate form of diflunisal precipitated from a microemulsion system.

    PubMed

    Sung, Hsuan-Lei; Fan, Yueh-Lin; Yeh, Kimberly; Chen, Yen-Fu; Chen, Li-Jen

    2013-09-01

    Three microemulsion systems were applied as solvents for polymorph screening of seven active pharmaceutical ingredients (APIs): carbamazepine, piroxicam, sulfaguanidine, nitrofurantoin, theophylline, quercetin, and diflunisal. All the recrystallized compounds were examined by using powder X-ray diffractometry, differential scanning calorimetry, elemental analysis, Karl Fischer titration and dissolution rate. A new crystal form of diflunisal hydrate was discovered by the cooling method of recrystallization in a water-in-oil microemulsion system, composed of water, alkane and dioctyl sodium sulfosuccinate. The new hydrate form of diflunisal was characterized and confirmed to be a stoichiometry of diflunisal:water of 1:1. The other two microemulsion systems were able to convert the anhydrous diflunisal Form I to Form III. The dissolution rate of diflunisal hydrate is unexpectedly much higher than that of anhydrous ones (Forms I and III). All the other six APIs (carbamazepine, piroxicam, sulfaguanidine, nitrofurantoin, theophylline and quercetin) recrystallized from the microemulsion systems were all converted into hydrate form. PMID:23624616

  20. Water, Hydration and Health

    PubMed Central

    Popkin, Barry M.; D’Anci, Kristen E.; Rosenberg, Irwin H.

    2010-01-01

    This review attempts to provide some sense of our current knowledge of water including overall patterns of intake and some factors linked with intake, the complex mechanisms behind water homeostasis, the effects of variation in water intake on health and energy intake, weight, and human performance and functioning. Water represents a critical nutrient whose absence will be lethal within days. Water’s importance for prevention of nutrition-related noncommunicable diseases has emerged more recently because of the shift toward large proportions of fluids coming from caloric beverages. Nevertheless, there are major gaps in knowledge related to measurement of total fluid intake, hydration status at the population level, and few longer-term systematic interventions and no published random-controlled longer-term trials. We suggest some ways to examine water requirements as a means to encouraging more dialogue on this important topic. PMID:20646222

  1. Dynamics of Protein Hydration Water

    E-print Network

    Wolf, M; Gulich, R; Lunkenheimer, P; Loidl, A

    2014-01-01

    We present the frequency- and temperature-dependent dielectric properties of lysozyme solutions in a broad concentration regime, measured at subzero temperatures and compare the results with measurements above the freezing point of water and on hydrated lysozyme powder. Our experiments allow examining the dynamics of unfreezable hydration water in a broad temperature range including the so-called No Man's Land (160 - 235 K). The obtained results prove the bimodality of the hydration shell dynamics and are discussed in the context of the highly-debated fragile-to-strong transition of water.

  2. Dynamics of Protein Hydration Water

    E-print Network

    M. Wolf; S. Emmert; R. Gulich; P. Lunkenheimer; A. Loidl

    2014-12-08

    We present the frequency- and temperature-dependent dielectric properties of lysozyme solutions in a broad concentration regime, measured at subzero temperatures and compare the results with measurements above the freezing point of water and on hydrated lysozyme powder. Our experiments allow examining the dynamics of unfreezable hydration water in a broad temperature range including the so-called No Man's Land (160 - 235 K). The obtained results prove the bimodality of the hydration shell dynamics and are discussed in the context of the highly-debated fragile-to-strong transition of water.

  3. Herbal extracts of Tribulus terrestris and Bergenia ligulata inhibit growth of calcium oxalate monohydrate crystals in vitro

    NASA Astrophysics Data System (ADS)

    Joshi, V. S.; Parekh, B. B.; Joshi, M. J.; Vaidya, A. B.

    2005-02-01

    A large number of people in this world are suffering from urinary stone problem. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) containing stones (calculi) are commonly found. In the present study, COM crystals were grown by a double diffusion gel growth technique using U-tubes. The gel was prepared from hydrated sodium metasilicate solution. The gel framework acts like a three-dimensional crucible in which the crystal nuclei are delicately held in the position of their formation, and nutrients are supplied for the growth. This technique can be utilized as a simplified screening static model to study the growth, inhibition and dissolution of urinary stones in vitro. The action of putative litholytic medicinal plants, Tribulus terrestris Linn. ( T.t) and Bergenia ligulata Linn. ( B.l.), has been studied in the growth of COM crystals. Tribulus terrestris and Bergenia ligulata are commonly used as herbal medicines for urinary calculi in India. To verify the inhibitive effect, aqueous extracts of Tribulus terrestris and Bergenia ligulata were added along with the supernatant solutions. The growth was measured and compared, with and without the aqueous extracts. Inhibition of COM crystal growth was observed in the herbal extracts. Maximum inhibition was observed in Bergenia ligulata followed by Tribulus terrestris. The results are discussed.

  4. Hydrates represent gas source, drilling hazard

    SciTech Connect

    Bagirov, E. [Azerbaijan Academy of Sciences, Baku (Azerbaijan); Lerche, I. [Univ. of South Carolina, Columbia, SC (United States)

    1997-12-01

    Gas hydrates look like ordinary ice. However, if a piece of such ice is put into warm water its behavior will be different from the ordinary melting of normal ice. In contrast, gas hydrates cause bubbles in the warm water, which indicates the high content of gas in the hydrate crystals. The presence of four components is required: gas itself, water, high pressure, and low temperature. The paper discusses how hydrates form, hydrates stability, South Caspian hydrates, and hydrates hazards for people, ships, pipelines, and drilling platforms.

  5. The geochemical evolution of aqueous sodium in the Black Creek Aquifer, Horry and Georgetown counties, South Carolina

    USGS Publications Warehouse

    Zack, Allen L.; Roberts, Ivan

    1988-01-01

    The Black Creek aquifer contains dilute seawater near the North Carolina State line, probably the result of incomplete flushing of ancient seawater. Data do not indicate that the dilute seawater has migrated toward areas of fresh ground-water withdrawals. The concentration of chloride in ground-water samples ranges from 5 to 720 milligrams per liter and that of sodium from 160 to 690 milligrams per liter. Ion-exchange reactions (sodium for calcium and fluoride for hydroxyl) occur with the calcium carbonate dissolution reaction which produces calcium, bicarbonate, and hydroxyl ions. The reaction sequence and stoichiometry result in an aqueous solution in which the sum of bicarbonate and chloride equivalents per liter is equal to the equivalents per liter of sodium. Calcium ions are exchanged for sodium ions derived from sodium-rich clays upgradient of the dilute seawater. The cation-exchange reaction equilibrates at a sodium concentration of 280 milligrams per liter. Amounts of sodium greater than 280 milligrams per liter are contributed from dilute seawater. The cation-exchange reaction approaches an equilibrium which represents a mass-action limit in terms of the ratio of sodium to calcium in solution versus the ratio of exchangeable sodium to calcium on clay surfaces. Where the limit of calcium carbonate solubility is approached and dissolution ceases, some precipitation of calcite probably takes place. The dissolution of calcite exposes fossil shark teeth which release fluoride ions to the ground water through anion exchange with aqueous hydroxyl ions.

  6. 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 ...

  7. Calcium and osteoporosis

    Microsoft Academic Search

    B. E. Christopher Nordin

    1997-01-01

    Calcium is an essential nutrient that is involved in most metabolic processes and the phosphate salts of which provide mechanical rigidity to the bones and teeth, where 99% of the body's calcium resides. The calcium in the skeleton has the additional role of acting as a reserve supply of calcium to meet the body's metabolic needs in states of calcium

  8. Hydrothermal transformation of the calcium aluminum oxide hydrates CaAl{sub 2}O{sub 4}.10H{sub 2}O and Ca{sub 2}Al{sub 2}O{sub 5}.8H{sub 2}O to Ca{sub 3}Al{sub 2}(OH){sub 12} investigated by in situ synchrotron X-ray powder diffraction

    SciTech Connect

    Jensen, Torben R. [Interdisciplinary Nanoscience Center, Department of Chemistry, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C (Denmark)]. E-mail: trj@chem.au.dk; Christensen, Axel Norlund [Hojkolvej 7, DK-8210 Arhus V (Denmark); Hanson, Jonathan C. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973, USA (United States)

    2005-12-15

    The hydrothermal transformation of calcium aluminate hydrates were investigated by in situ synchrotron X-ray powder diffraction in the temperature range 25 to 170 deg. C. This technique allowed the study of the detailed reaction mechanism and identification of intermediate phases. The material CaAl{sub 2}O{sub 4}.10H{sub 2}O converted to Ca{sub 3}Al{sub 2}(OH){sub 12} and amorphous aluminum hydroxide. Ca{sub 2}Al{sub 2}O{sub 5}.8H{sub 2}O transformed via the intermediate phase Ca{sub 4}Al{sub 2}O{sub 7}.13H{sub 2}O to Ca{sub 3}Al{sub 2}(OH){sub 12} and gibbsite, Al(OH){sub 3}. The phase Ca{sub 4}Al{sub 2}O{sub 7}.19H{sub 2}O reacted via the same intermediate phase to Ca{sub 3}Al{sub 2}(OH){sub 12} and mainly amorphous aluminum hydroxide. The powder pattern of the intermediate phase is reported.

  9. Pravastatin sodium.

    PubMed

    Al-Badr, Abdullah A; Mostafa, Gamal A E

    2014-01-01

    Pravastatin sodium is an [HMG-CoA] reductase inhibitor and is a lipid-regulating drug. This monograph includes the description of the drug: nomenclature, formulae, elemental composition, solubility, appearance, and partition coefficient. The uses and the methods that have been reported for the synthesis of this drug are described. The physical methods that were used to characterize the drug are the X-ray powder diffraction pattern, thermal methods, melting point, and differential scanning calorimetry. This chapter also contains the following spectra of the drug: the ultraviolet spectrum, the vibrational spectrum, the nuclear magnetic resonance spectra, and the mass spectrum. The compendial methods of analysis include the British Pharmacopoeia and the United States Pharmacopoeia methods. Other methods of analysis that are included in this profile are spectrophotometric, electrochemical, polarographic, voltammetric and chromatographic, and immunoassay methods. The chapter also contains the pharmacokinetics, metabolism, stability, and articles that reviewed pravastatin sodium manufacturing, characterization, and analysis. One hundred and sixty-two references are listed at the end of this comprehensive profile. PMID:24794911

  10. In-situ early-age hydration study of sulfobelite cements by synchrotron powder diffraction

    SciTech Connect

    Álvarez-Pinazo, G.; Cuesta, A.; García-Maté, M.; Santacruz, I.; Losilla, E.R. [Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos S/N., 29071 Málaga (Spain)] [Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos S/N., 29071 Málaga (Spain); Sanfélix, S.G. [Unidad Técnica de Investigación de Materiales, AIDICO, Avda. Benjamín Franklin, 17 Paterna, Valencia (Spain)] [Unidad Técnica de Investigación de Materiales, AIDICO, Avda. Benjamín Franklin, 17 Paterna, Valencia (Spain); Fauth, F. [CELLS-Alba synchrotron, Carretera BP 1413, Km. 3.3, E-08290 Cerdanyola, Barcelona (Spain)] [CELLS-Alba synchrotron, Carretera BP 1413, Km. 3.3, E-08290 Cerdanyola, Barcelona (Spain); Aranda, M.A.G. [Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos S/N., 29071 Málaga (Spain) [Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos S/N., 29071 Málaga (Spain); CELLS-Alba synchrotron, Carretera BP 1413, Km. 3.3, E-08290 Cerdanyola, Barcelona (Spain); De la Torre, A.G., E-mail: mgd@uma.es [Departamento de Química Inorgánica, Universidad de Málaga, Campus Teatinos S/N., 29071 Málaga (Spain)

    2014-02-15

    Eco-friendly belite calcium sulfoaluminate (BCSA) cement hydration behavior is not yet well understood. Here, we report an in-situ synchrotron X-ray powder diffraction study for the first hours of hydration of BCSA cements. Rietveld quantitative phase analysis has been used to establish the degree of reaction (?). The hydration of a mixture of ye'elimite and gypsum revealed that ettringite formation (? ? 70% at 50 h) is limited by ye'elimite dissolution. Two laboratory-prepared BCSA cements were also studied: non-active-BCSA and active-BCSA cements, with ?- and ??{sub H}-belite as main phases, respectively. Ye'elimite, in the non-active-BCSA system, dissolves at higher pace (? ? 25% at 1 h) than in the active-BCSA one (? ? 10% at 1 h), with differences in the crystallization of ettringite (? ? 30% and ? ? 5%, respectively). This behavior has strongly affected subsequent belite and ferrite reactivities, yielding stratlingite and other layered phases in non-active-BCSA. The dissolution and crystallization processes are reported and discussed in detail. -- Highlights: •Belite calcium sulfoaluminate cements early hydration mechanism has been determined. •Belite hydration strongly depends on availability of aluminum hydroxide. •Orthorhombic ye’elimite dissolved at a higher pace than cubic one. •Ye’elimite larger reaction degree yields stratlingite formation by belite reaction. •Rietveld method quantified gypsum, anhydrite and bassanite dissolution rates.

  11. Module 11 – Withdrawing Nutrition, Hydration

    Cancer.gov

    Module eleven of the EPEC-O Self-Study Original Version discusses the general aspects of withholding or withdrawing of life-sustaining therapies, and presents a specific application to artificial nutrition and hydration.

  12. Deep water cycle: Mantle hydration

    NASA Astrophysics Data System (ADS)

    Nishi, Masayuki

    2015-01-01

    The fate of water that enters the mantle within subducting slabs is unclear. Laboratory experiments indicate that subducted crust can transport large amounts of water into the deep Earth, and the lower mantle may become more hydrated over time.

  13. High-pressure gas hydrates 

    E-print Network

    Loveday, J. S.; Nelmes, R. J.

    pressures. Clathrate hydrates have been extensively studied because they occur widely in nature, have important industrial applications, and provide insight into water-guest hydrophobic interactions. Until recently, the expectation-based on calculations...

  14. Crystallization of a polymorphic hydrate system.

    PubMed

    Tian, F; Qu, H; Louhi-Kultanen, M; Rantanen, J

    2010-02-01

    Nitrofurantoin can form two monohydrates, which have the same chemical composition and molar ratio of water, but differ in the crystal arrangements. The two monohydrates (hydrates I and II) could be produced independently via evaporative crystallization, where supersaturation and solvent composition were both found to have an effect. Hydrate I showed much slower crystallization than hydrate II. During cooling crystallization, the nucleation and growth of hydrate II was again dominant, consuming all supersaturation and leading to no hydrate I formation. Seeding of hydrate I during cooling crystallization was also applied, but the hydrate I seeds were not able to initiate its nucleation rather than dissolving into crystallizing solution. Although solubility tests revealed that hydrate II is more stable than hydrate I due to its lower solubility (110 +/- 4 and 131 +/- 12 microg/mL for hydrates II and I, respectively), this difference is rather small. Therefore, the small free energy difference between the two hydrates, together with the slow crystallization of hydrate I, both lead to a hindrance of hydrate I formation. Furthermore, the crystal structure of hydrate II demonstrated a higher H-bonding extent than hydrate I, suggesting its more favorable crystallization. This is in good agreement with experimental results. PMID:19569226

  15. Calcium Collage

    NSDL National Science Digital Library

    OMSI

    2004-01-01

    In this activity (on pages 11-14 of PDF), learners cut out pictures from magazines of foods that help make bones strong and glue the pictures to a paper bone. The lesson plan includes information about various activities - including physical exercise as well as diet - that lead to healthy bones. It also includes a list of foods that provide calcium to strengthen bones, including dairy products, spinach, and tofu. The paper bones can be cut out of construction paper prior to the activity.

  16. Methane hydrate stability in seawater

    Microsoft Academic Search

    Gerald R. Dickens; M. S. Quinby-Hunt

    1994-01-01

    Experiment data are presented for methane hydrate stability conditions in seawater (S ⼠33.5 {per_thousand}). For the pressure range of 2.75-10.0 MPa, at any given pressure, the dissociation temperature of methane hydrate is depressed by approximately -1.1 °C relative to the pure methane-pure water system. These experimental results are consistent with previously reported thermodynamic predictions and experimental results obtained with

  17. Calcium hydroxide poisoning

    MedlinePLUS

    Calcium hydroxide is a white powder produced by mixing calcium oxide ("lime") with water. Calcium hydroxide poisoning ... Blood in the stool Burns in the esophagus (food pipe) Severe abdominal pain Vomiting Vomiting blood Heart ...

  18. 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 ...

  19. 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 ...

  20. 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 ...

  1. Get Enough Calcium

    MedlinePLUS

    ... Physical Activity > Nutrition > Get Enough Calcium Get Enough Calcium The Basics Take Action! Ver en español Content ... February 24, 2015 The Basics Your body needs calcium to build strong bones when you are young ...

  2. Calcium-Rich Foods

    MedlinePLUS

    ... Disorders - Osteoporosis - Prevention - Calcium - Calcium content of common foods Printer friendly Email Share Tweet Like Below is ... Green/French beans 90 g cooked 50 Starchy foods Food Serving Size Calcium (mg) Pasta (cooked) 180 ...

  3. Allosteric Activation of Sodium-Calcium Exchange Activity by Calcium: Persistence at Low Calcium Concentrations

    Microsoft Academic Search

    John P. Reeves; Madalina Condrescu

    2003-01-01

    The activity of the cardiac Na ? \\/Ca 2 ? exchanger is stimulated allosterically by Ca 2 ? , but estimates of the half-maximal activating concentration have varied over a wide range. In Chinese hamster ovary cells express- ing the cardiac Na ? \\/Ca 2 ? exchanger, the time course of exchange-mediated Ca 2 ? influx showed a pronounced lag

  4. Aqueous solubility of calcium L-lactate, calcium D-gluconate, and calcium D-lactobionate: importance of complex formation for solubility increase by hydroxycarboxylate mixtures.

    PubMed

    Vavrusova, Martina; Munk, Merete Bøgelund; Skibsted, Leif H

    2013-08-28

    Among the calcium hydroxycarboxylates important for cheese quality, D-lactobionate [Ksp = (7.0 ± 0.3) × 10(-3) mol(3) L(-3)] and L-lactate [Ksp = (5.8 ± 0.2) × 10(-3) mol(3) L(-3)] were found more soluble than D-gluconate [Ksp = (7.1 ± 0.2) × 10(-4) mol(3) L(-3)], as indicated by the solubility products determined electrochemically for aqueous 1.0 M NaCl at 25.0 °C. Still, solubility of calcium L-lactate increases by 45% in the presence of 0.50 M sodium D-gluconate and by 37% in the presence of 0.50 M sodium D-lactobionate, while solubility of calcium D-gluconate increases by 66 and 85% in the presence of 0.50 M sodium L-lactate and 0.50 M sodium D-lactobionate, respectively, as determined by complexometric titration. Sodium L-lactate and sodium D-gluconate have only little influence on solubility of calcium D-lactobionate. The increased solubility is described quantitatively by calcium binding to D-gluconate (K1 = 14 ± 3 mol(-1) L) in 1.0 M NaCl at 25 °C, D-lactobionate (K1 = 11 ± 2 mol(-1) L), and L-lactate (K1 = 8 ± 2 mol(-1) L), as indicated by the association constants determined electrochemically. In mixed hydroxycarboxylate solutions, calcium binding is quantitatively described by the geometric mean of the individual association constants for both aqueous 1.0 and 0.20 M NaCl, indicating a 1:1 stoichiometry for complex formation. PMID:23906043

  5. Characterization of pore solutions expressed from high-calcium fly-ash–water pastes

    Microsoft Academic Search

    J. K. Tishmack; J. Olek; S. Diamond; S. Sahu

    2001-01-01

    A pore solution study was undertaken to provide additional understanding of the hydration behavior of high-calcium fly ash in fly-ash–water pastes. Three sources of fly ash were selected from a previous study on the basis of their hydration behavior, particularly their ability to form ettringite. Pastes were made from each fly ash and water, and pore solutions were expressed at

  6. Carbonation Behavior of Pure Cement Hydrates under Supercritical Carbon Dioxide Conditions - 12199

    SciTech Connect

    Hirabayashi, Daisuke; Enokida, Youichi [Graduate School of Engineering, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya-shi, Aichi-ken, 464-8603 (Japan); Sawada, Kayo [EcoTopia Science Institute, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya-shi, Aichi-ken, 464-8603 (Japan); Hertz, Audrey; Charton, Frederic [CEA, DEN, Marcoule, DTCD/SPDE/L2ED, BP 17171, F-30207 Bagnols-sur-Ceze (France); Frizon, Fabien [CEA, DEN, Marcoule, DTCD/SPDE/LFSM, BP 17171, F-30207 Bagnols-sur-Ceze (France); Brouno, Fournel [CEA, DEN, Marcoule, DTCD, BP 17171, F-30207 Bagnols-sur-Ceze (France)

    2012-07-01

    Carbonation of cement-based waste forms using a supercritical carbon dioxide (SCCO{sub 2}) is a developing technology for the waste immobilization of radioactive and non-radioactive wastes. However, the detail carbonation behaviors of cement matrices under the SCCO{sub 2} condition are unknown, since cement matrices forms very complex phases. In this study, in order to clarify the crystal phases, we synthesized pure cement hydrate phases as each single phases; portlandite (Ca(OH){sub 2}), ettringite (Ca{sub 6}Al{sub 2}(SO{sub 4}){sub 3}(OH){sub 12}.26H{sub 2}O), and calcium silicate hydrate (n CaO---m SiO{sub 2} ---x H{sub 2}O), using suspensions containing a stoichiometric mixture of chemical regents, and performed carbonation experiments using an autoclave under supercritical condition for carbon dioxide. The XRD results revealed both the carbonate phases and co-product phases depending on the initial hydrate phases; gypsum for Ettringite, amorphous or crystalline silica for calcium silicate hydroxide. Thermogravimetric analysis was also performed to understand carbonation behaviors quantitatively. According to the experimental results, it was found that the major reaction was formation of calcium carbonate (CaCO{sub 3}) in all cases. However, the behaviors of H{sub 2}O and CO{sub 2} content were quietly different: Portlandite was most reactive for carbonation under SCCO{sub 2} conditions, and the CO{sub 2} content per one molar CaO was ranged from 0.96 ? 0.98. In the case of Ettringite, the experiment indicates partial decomposition of ettringite phase during carbonation. Ettringite was comparatively stable even under the SCCO{sub 2} conditions. Therefore, a part of ettringite remained and formed similar phases after the ettringite carbonation. The CO{sub 2} content for ettringite showed almost constant values around 0.86 ? 0.87. In the case of calcium silicate hydrate, the carbonation behavior was significantly influenced by the condition of SCCO{sub 2}. The CO{sub 2} content for the calcium silicate hydrate had values that ranged from 0.51 ? 1.01. The co-products of the carbonation were gypsum (CaSO{sub 4}) for ettringite, silica gel (SiO{sub x}) and silica (SiO{sub 2}) for calcium silicate hydrate, which also contributed to the densification of the particles. The production of co-products enhanced the change to their morphology after the carbonation. (authors)

  7. Sodium nitroprusside suppresses male fertility in vitro.

    PubMed

    Rahman, M S; Kwon, W-S; Lee, J-S; Kim, J; Yoon, S-J; Park, Y-J; You, Y-A; Hwang, S; Pang, M-G

    2014-11-01

    Sodium nitroprusside is a nitric oxide donor involved in the regulation of the motility, hyperactivation, capacitation, and acrosome reaction (AR) of spermatozoa. However, the molecular mechanism underlying this regulation has not yet been elucidated. Therefore, this study was designed to evaluate the molecular basis for the effects of sodium nitroprusside on different processes in spermatozoa and its consequences on subsequent oocyte fertilization and embryo development. In this in vitro study, mouse spermatozoa were incubated with various concentrations of sodium nitroprusside (1, 10, and 100 ?M) for 90 min. Our results showed that sodium nitroprusside inhibited sperm motility and motion kinematics in a dose-dependent manner by significantly enhancing intracellular iron and reactive oxygen species (ROS), and decreasing Ca(2+), and adenosine triphosphate levels in spermatozoa. Moreover, short-term exposure of spermatozoa to sodium nitroprusside increased the tyrosine phosphorylation of sperm proteins involved in PKA-dependent regulation of intracellular calcium levels, which induced a robust AR. Finally, sodium nitroprusside significantly decreased the rates of fertilization and blastocyst formation during embryo development. Based on these results, we propose that sodium nitroprusside increases ROS production and precocious AR may alter overall sperm physiology, leading to poor fertilization and compromised embryonic development. PMID:25180787

  8. Sodium-23 solid-state nuclear magnetic resonance of commercial sodium naproxen and its solvates.

    PubMed

    Burgess, Kevin M N; Perras, Frédéric A; Lebrun, Aurore; Messner-Henning, Elisabeth; Korobkov, Ilia; Bryce, David L

    2012-08-01

    We report on the investigation of sodium coordination environments with solid-state ²³Na nuclear magnetic resonance (NMR) spectroscopy of various hydrates and solvates of sodium naproxen (SN), a commercially available anti-inflammatory drug sold over the counter as Aleve®, among other names. The ²³Na quadrupolar coupling constant is found to change significantly depending on the hydration state, and subtle changes in oxygen coordination environment about the sodium cations were apparent in the NMR spectra. High-resolution double-rotation NMR experiments are also performed on powdered samples to obtain solution-like ²³Na NMR spectra. Our attempts at crystallizing various solvates of SN have led to the characterization of the first crystal structure for the heminonahydrated form. The composition of commercial SN is also investigated and it is shown that Aleve® is composed of approximately 80% monohydrate solvate. Density-functional theory calculations, using the gauge-including projector-augmented-wave formalism, allow for the assignment of ²³Na NMR peaks to specific sodium sites in the reported X-ray crystal structure. PMID:22619061

  9. Ground-Based Detection of Exoatmospheric Calcium

    NASA Astrophysics Data System (ADS)

    Rojo, Patricio M.; Astudillo-Defru, Nicola

    2014-11-01

    Data acquired with HDS@Subaru for HD209458b is re-analyzed. A new pipeline performs an automated search for the exoatmospheric presence of several elements without any a-priori assumptions on its existence or strength. We analyzed thousands of lines in the full spectral range of this optical echelle spectrograph using a robust method to correct for the telluric contamination. We recover previous detections of Sodium and Halpha, and present the first strong detection of Calcium in an Extrasolar Atmosphere as well as the tentative detection of other elements. The Calcium detection is in disagreement with theoretical thermal-equilibrium models.

  10. Presynaptic calcium currents in squid giant synapse.

    PubMed Central

    Llinás, R; Steinberg, I Z; Walton, K

    1981-01-01

    A voltage clamp study has been performed in the presynaptic terminal of the squid stellate ganglion. After blockage of the voltage-dependent sodium and potassium conductances, an inward calcium current is demonstrated. Given a step-depolarization pulse, this voltage- and time-dependent conductance has an S-shaped onset. At the "break" of the voltage step, a rapid tail current is observed. From these results a kinetic model is generated which accounts for the experimental results and predicts for the time course and amplitude a possible calcium entry during presynaptic action potentials. Images FIGURE 1 PMID:7225510

  11. A realistic molecular model of cement hydrates

    PubMed Central

    Pellenq, Roland J.-M.; Kushima, Akihiro; Shahsavari, Rouzbeh; Van Vliet, Krystyn J.; Buehler, Markus J.; Yip, Sidney; Ulm, Franz-Josef

    2009-01-01

    Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these characteristics of C-S-H define and modulate the physical and mechanical properties of this “liquid stone” gel phase. With the recent determination of the calcium/silicon (C/S = 1.7) ratio and the density of the C-S-H particle (2.6 g/cm3) by neutron scattering measurements, there is new urgency to the challenge of explaining these essential properties. Here we propose a molecular model of C-S-H based on a bottom-up atomistic simulation approach that considers only the chemical specificity of the system as the overriding constraint. By allowing for short silica chains distributed as monomers, dimers, and pentamers, this C-S-H archetype of a molecular description of interacting CaO, SiO2, and H2O units provides not only realistic values of the C/S ratio and the density computed by grand canonical Monte Carlo simulation of water adsorption at 300 K. The model, with a chemical composition of (CaO)1.65(SiO2)(H2O)1.75, also predicts other essential structural features and fundamental physical properties amenable to experimental validation, which suggest that the C-S-H gel structure includes both glass-like short-range order and crystalline features of the mineral tobermorite. Additionally, we probe the mechanical stiffness, strength, and hydrolytic shear response of our molecular model, as compared to experimentally measured properties of C-S-H. The latter results illustrate the prospect of treating cement on equal footing with metals and ceramics in the current application of mechanism-based models and multiscale simulations to study inelastic deformation and cracking. PMID:19805265

  12. Storability and germination of sodium alginate encapsulated somatic embryos derived from the vegetative shoot apices of mature Pinus patula trees

    Microsoft Academic Search

    Ravindra B. Malabadi; J. van. Staden

    2005-01-01

    Storability and germination of sodium alginate encapsulated somatic embryos derived from vegetative shoot apices of mature Pinus patula trees were tested on half strength DCR basal medium without growth regulators. The germination percentage of encapsulated somatic embryos was affected significantly by the concentration of sodium alginate and the duration of exposure to calcium chloride. Somatic embryos encapsulated with 2.5 sodium

  13. A calorimetric study of early hydration of alkali-slag cements

    Microsoft Academic Search

    Caijun Shi; Robert L. Day

    1995-01-01

    This paper examines the early hydration of alkali-slag cements activated by different sodium compounds, such as NaOH, Na2CO3, Na2SiO3.5H2O, Na3PO4, Na2HPO4 and NaF, at 25 and 50 °C. A conduction calorimeter was used to monitor hydration kinetics. It was found that the initial pH of activator solution has an important role in dissolving the slag and in promoting the early

  14. Adsorption of polyelectrolytes and its influence on the rheology, zeta potential, and microstructure of various cement and hydrate phases.

    PubMed

    Zingg, Anatol; Winnefeld, Frank; Holzer, Lorenz; Pakusch, Joachim; Becker, Stefan; Gauckler, Ludwig

    2008-07-15

    In this study the influence of polycarboxylate-based polyelectrolytes on the particle interaction among tricalcium silicate (C(3)S, main clinker phase), calcium silicate hydrates (CSH), and calcium aluminate sulfate hydrates (ettringite) (main hydration phases) has been examined. These phases are the constituents of major concern during early hydration of cement suspensions. The results of zeta potential measurements on single mineral phase experiments show that the phases C(3)S and CSH are positively charged in synthetic pore solution (liquid phase of hydrating cement suspension), whereas the ettringite is negatively charged. Due to these opposite charges, ettringite crystals should coagulate with CSH phases and/or deposit on surfaces of the much larger C(3)S clinker particles. This behavior was proven by cryo-microscopic analysis of high-pressure frozen cement suspensions, which illustrates the consequences of colloidal mechanisms on the microstructure of early cement suspensions. Furthermore, it is shown that the polyelectrolytes have a much higher adsorption affinity to ettringite surfaces (hydrate phase) compared to silicate surfaces. However, the results from rheology experiments reveal that the presence of polyelectrolytes has a strong impact on the suspension properties of all investigated mineral phases by decreasing yield stress and plastic viscosity. From the results it can be concluded that the ettringite is the dominant mineral phase in terms of the state of dispersion which includes particle-particle and particle-polyelectrolyte interaction in the bulk cement system. PMID:18502439

  15. Methane hydrates and global climate

    NASA Astrophysics Data System (ADS)

    Kvenvolden, Keith A.

    1988-09-01

    Methane hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. The amount of methane sequestered in gas hydrates is probably enormous, but estimates of the amounts are speculative and range over three orders of magnitude (about 103 to 106 GT (gigatons = 1015 g)). A question of current interest concerns the possible consequences of an addition of methane to the atmosphere from destabilized methane hydrates due to global warming. Models of greenhouse warming predict that climatic change will be greatest in the Arctic. Thus, if methane from destabilized gas hydrates contributes to greenhouse warming, this destabilization will most likely take place first in the Arctic, particularly in the shallow nearshore regions of the Arctic Ocean where offshore permafrost is found. The process of permafrost warming and release of methane from gas hydrates may already be in progress, but the amount being released now and to be released in the 21st century is probably small. The positive feedback of this atmospheric methane on global climates will likely be minimal.

  16. Well log evaluation of natural gas hydrates

    SciTech Connect

    Collett, T.S.

    1992-10-01

    Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.

  17. Well log evaluation of natural gas hydrates

    SciTech Connect

    Collett, T.S.

    1992-10-01

    Gas hydrates are crystalline substances composed of water and gas, in which a solid-water-lattice accommodates gas molecules in a cage-like structure. Gas hydrates are globally widespread in permafrost regions and beneath the sea in sediment of outer continental margins. While methane, propane, and other gases can be included in the clathrate structure, methane hydrates appear to be the most common in nature. The amount of methane sequestered in gas hydrates is probably enormous, but estimates are speculative and range over three orders of magnitude from about 100,000 to 270,000,000 trillion cubic feet. The amount of gas in the hydrate reservoirs of the world greedy exceeds the volume of known conventional gas reserves. Gas hydrates also represent a significant drilling and production hazard. A fundamental question linking gas hydrate resource and hazard issues is: What is the volume of gas hydrates and included gas within a given gas hydrate occurrence? Most published gas hydrate resource estimates have, of necessity, been made by broad extrapolation of only general knowledge of local geologic conditions. Gas volumes that may be attributed to gas hydrates are dependent on a number of reservoir parameters, including the areal extent ofthe gas-hydrate occurrence, reservoir thickness, hydrate number, reservoir porosity, and the degree of gas-hydrate saturation. Two of the most difficult reservoir parameters to determine are porosity and degreeof gas hydrate saturation. Well logs often serve as a source of porosity and hydrocarbon saturation data; however, well-log calculations within gas-hydrate-bearing intervals are subject to error. The primary reason for this difficulty is the lack of quantitative laboratory and field studies. The primary purpose of this paper is to review the response of well logs to the presence of gas hydrates.

  18. Alternative Splicing of an Insect Sodium Channel Gene Generates Pharmacologically Distinct Sodium Channels

    PubMed Central

    Tan, Jianguo; Liu, Zhiqi; Nomura, Yoshiko; Goldin, Alan L.; Dong, Ke

    2011-01-01

    Alternative splicing is a major mechanism by which potassium and calcium channels increase functional diversity in animals. Extensive alternative splicing of the para sodium channel gene and developmental regulation of alternative splicing have been reported in Drosophila species. Alternative splicing has also been observed for several mammalian voltage-gated sodium channel genes. However, the functional significance of alternative splicing of sodium channels has not been demonstrated. In this study, we identified three mutually exclusive alternative exons encoding part of segments 3 and 4 of domain III in the German cockroach sodium channel gene, paraCSMA. The splice site is conserved in the mouse, fish, and human Nav1.6 sodium channel genes, suggesting an ancient origin. One of the alternative exons possesses a stop codon, which would generate a truncated protein with only the first two domains. The splicing variant containing the stop codon is detected only in the PNS, whereas the other two full-size variants were detected in both the PNS and CNS. When expressed in Xenopus oocytes, the two splicing variants produced robust sodium currents, but with different gating properties, whereas the splicing variant with the stop codon did not produce any detectable sodium current. Furthermore, these two functional splicing variants exhibited a striking difference in sensitivity to a pyrethroid insecticide, deltamethrin. Exon swapping partially reversed the channel sensitivity to deltamethrin. Our results therefore provide the first evidence that alternative splicing of a sodium channel gene produces pharmacologically distinct channels. PMID:12097481

  19. Update on Calcium Signaling Calcium Signaling through Protein Kinases. The

    E-print Network

    Sheen, Jen

    Update on Calcium Signaling Calcium Signaling through Protein Kinases. The Arabidopsis Calcium protein kinase activities occur through calcium-dependent protein kinases (CDPKs). These novel calcium provides a valuable opportunity to understand the plant calcium-signaling network. Calcium is a ubiquitous

  20. Hydrophobic hydration of amphipathic peptides.

    PubMed Central

    Cheng, Y K; Sheu, W S; Rossky, P J

    1999-01-01

    Biomolecular surfaces and interfaces are commonly found with apolar character. The hydrophobic effect thus plays a crucial role in processes involving association with biomolecular surfaces in the cellular environment. By computer simulation, we compared the hydrogen bonding structures and energetics of the proximal hydration shells of the monomer and dimer from a recent study of an extrinsic membrane peptide, melittin. The two peptides were studied in their amphipathic alpha-helical forms, which possess extended hydrophobic surfaces characterized by different topography. The topography of the peptide-water interface was found to be critical in determining the enthalpic nature of hydrophobic hydration. This topographical dependence has far-reaching implications in the regulation of bioactivities in the presence of amphipathicity. This result also engenders reconsideration of the validity of using free energy parameters that depend solely on the chemical nature of constituent moieties in characterizing hydrophobic hydration of proteins and biomolecules in general. PMID:10096874

  1. Polymorphs and Hydrates of Acyclovir

    PubMed Central

    LUTKER, KATIE M.; QUIÑONES, ROSALYNN; XU, JIADI; RAMAMOORTHY, AYYALUSAMY; MATZGER, ADAM J.

    2011-01-01

    Acyclovir (ACV) has been commonly used as an antiviral for decades. Although the crystal structure of the commercial form, a 3:2 ACV/water solvate, has been known since 1980s, investigation into the structure of anhydrous ACV has been limited. Here, we report the characterization of four anhydrous forms of ACV and a new hydrate in addition to the known hydrate. Two of the anhydrous forms appear as small needles and are stable to air exposure, whereas the third form is morphologically similar but quickly absorbs water from the atmosphere and converts back to the commercial form. The high-temperature modification is achieved by heating anhydrous form I above 180°C. The crystal structures of anhydrous form I and a novel hydrate are reported for the first time. PMID:21280051

  2. Phase transitions in biogenic amorphous calcium carbonate

    PubMed Central

    Gong, Yutao U. T.; Killian, Christopher E.; Olson, Ian C.; Appathurai, Narayana P.; Amasino, Audra L.; Martin, Michael C.; Holt, Liam J.; Wilt, Fred H.; Gilbert, P. U. P. A.

    2012-01-01

    Crystalline biominerals do not resemble faceted crystals. Current explanations for this property involve formation via amorphous phases. Using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), here we examine forming spicules in embryos of Strongylocentrotus purpuratus sea urchins, and observe a sequence of three mineral phases: hydrated amorphous calcium carbonate (ACC·H2O) ? dehydrated amorphous calcium carbonate (ACC) ? calcite. Unexpectedly, we find ACC·H2O-rich nanoparticles that persist after the surrounding mineral has dehydrated and crystallized. Protein matrix components occluded within the mineral must inhibit ACC·H2O dehydration. We devised an in vitro, also using XANES-PEEM, assay to identify spicule proteins that may play a role in stabilizing various mineral phases, and found that the most abundant occluded matrix protein in the sea urchin spicules, SM50, stabilizes ACC·H2O in vitro. PMID:22492931

  3. A marine electromagnetic survey to detect gas hydrate at Hydrate Ridge, Oregon

    Microsoft Academic Search

    K. A. Weitemeyer; S. Constable; A. M. Tréhu

    2011-01-01

    Gas hydrates are a potential energy resource and hazard for drilling and infrastructure, yet estimates of global volume vary by over three orders of magnitude. Hydrates are electrically resistive compared to water saturated sediment and so electromagnetic methods provide an additional tool to seismic surveys and drilling for determining hydrate saturations. A marine electromagnetic survey was carried out at Hydrate

  4. PYRETHROID INDUCED ALTERATIONS IN TRANSCRIPTION OF CALCIUM RESPONSIVE AND IMMEDIATE EARLY GENES IN VIVO.

    EPA Science Inventory

    Multiple molecular targets for pyrethroid insecticides have been evaluated in in vitro preparations, including but not limited to voltage-sensitive sodium channels (VSSCs), voltage-sensitive calcium channels (VSCCs), GABAergic receptors, ATPases and mitochondrial respiratory chai...

  5. Sodium valproate induced gingival enlargement in 22 months old child

    PubMed Central

    Dhalkari, Chandulal Digambarrao; Ganatra, Pallav Virendra

    2014-01-01

    Gingival enlargement is a common clinical feature seen in patients suffering from gingival and periodontal diseases and is a common side-effect of drugs such as anti-convulsants, calcium channel blockers and immunosuppresants. This is a case report of 22 months old child suffering from gingival enlargement following intake of sodium valproate. Among the anti-convulsants phenytoin is commonly associated with gingival enlargement; however, there are not many cases reported on sodium valproate induced gingival enlargement. PMID:25425829

  6. Preparation of monodispersed cubic calcium carbonate particles via precipitation reaction

    Microsoft Academic Search

    Bei Cheng; Ming Lei; Jiaguo Yu; Xiujian Zhao

    2004-01-01

    Monodispersed cubic calcium carbonate composite particles were prepared by the precipitation reaction of sodium carbonate with calcium chloride in water in the presence of polyacrylic acid (PAA) at 60–80 °C, and then characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Differential Scanning Calorimetry-Thermogravimetry (DSC-TG). It was found from the above results that variations in the concentration of PAA

  7. DNA-mediated morphosynthesis of calcium carbonate particles

    Microsoft Academic Search

    Bei Cheng; Weiquan Cai; Jiaguo Yu

    2010-01-01

    Calcium carbonate microspheres with different surface structures were successfully prepared by the reaction of sodium carbonate with calcium chloride in the presence of deoxyribonucleic acid (DNA) at room temperature. The as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and differential scanning calorimetry (TGA–DSC) and fourier-transform infrared spectrometry (FTIR). The effects

  8. Hydration of hyaluronan: effects on structural and thermodynamic properties.

    PubMed

    Albèr, Cathrine; Engblom, Johan; Falkman, Peter; Kocherbitov, Vitaly

    2015-03-19

    Hyaluronan (HA) is a frequently occurring biopolymer with a large variety of functions in nature. During the past 60 years, there have been numerous reports on structural and dynamic behavior of HA in water. Nevertheless, studies covering a wider concentration range are still lacking. In this work, we use isothermal scanning sorption calorimetry for the first time to investigate hydration-induced transitions in HA (sodium hyaluronate, 17 kDa). From this method, we obtain the sorption isotherm and the enthalpy and the entropy of hydration. Thermotropic events are evaluated by differential scanning calorimetry (DSC), and structure analysis is performed with X-ray scattering (SWAXS) and light and scanning electron microscopy. During isothermal hydration, HA exhibits a glass transition, followed by crystallization and subsequent dissolution of HA crystals and formation of a one-phase solution. Structural analysis reveals that the crystal may be indexed on an orthorhombic unit cell with space group P212121. Crystallization of HA was found to occur either through endothermic or exothermic processes, depending on the temperature and water content. We propose a mechanism of crystallization that explains this phenomenon based on the interplay between the hydrophobic effect and strengthening of hydrogen bonds during formation of crystals. The combined results were used to construct a binary phase diagram for the HA-water system. PMID:25719495

  9. Effects of thyroid status on renal calcium and magnesium handling.

    PubMed Central

    McCaffrey, C; Quamme, G A

    1984-01-01

    Renal calcium and magnesium handling was studied in rats with chronic thyroid hormone deficiency or excess, hyperthyroidism. Mean kidney weight of the thyroid deficient rats was 42% of age matched, euthyroid and hyperthyroid animals and glomerular filtration rate was 71% of normal. Fractional sodium excretion was consistently elevated in thyroid deficient rats (0.26%) as compared to euthyroid (0.07%) and hyperthyroid animals (0.07%). Urinary calcium excretion (0.39%) was also elevated and parallel to sodium excretion in thyroid deficiency. Despite this renal leak of sodium and calcium, thyroid deficient animals conserved magnesium much more efficiently than either euthyroid or hyperthyroid rats (5.7% vs 17.4% respectively). Plasma magnesium concentration was elevated by acute MgCl2 infusions to determine the reabsorptive capacity of magnesium. Thyroid deficient rats reabsorbed 15-30% more of the filtered magnesium at any given plasma concentration. Although these effects on electrolyte reabsorption are modest compared to the hemodynamic alterations, the data suggest that thyroid hormone has a direct effect on the tubule which if chronically absent results in subtle sodium and calcium wasting and renal retention of magnesium. Administration of thyroid hormone to euthyroid or thyroid deficient rats twenty-four hours prior to experimentation had no effect on calcium and magnesium handling. PMID:6713257

  10. Gas hydrates in the Gulf of Mexico

    E-print Network

    Cox, Henry Benjamin

    1986-01-01

    pipelines (Katz et al, 1959). The combination of water, gas and pressure in the pipeline formed hydrates. The hydrates were eliminated by drying the gas before introduction into the pipeline (Hammerschmidt, 1940). The structural types, shapes... of Mexico gas hydrate had porewater chlorinities that increased with depth reaching 41. 8 ppt Cl two meters into the sediment. The increase was attributed to diffusion from underlying salt diapirs and exclusion of salts from the hydrate lattice (Brooks...

  11. Hydration of highly charged ions

    PubMed Central

    Hofer, Thomas S.; Weiss, Alexander K.H.; Randolf, Bernhard R.; Rode, Bernd M.

    2011-01-01

    Based on a series of ab initio quantum mechanical charge field molecular dynamics (QMCF MD) simulations, the broad spectrum of structural and dynamical properties of hydrates of trivalent and tetravalent ions is presented, ranging from extreme inertness to immediate hydrolysis. Main group and transition metal ions representative for different parts of the periodic system are treated, as are 2 threefold negatively charged anions. The results show that simple predictions of the properties of the hydrates appear impossible and that an accurate quantum mechanical simulation in cooperation with sophisticated experimental investigations seems the only way to obtain conclusive results. PMID:22298911

  12. Gas Hydrate and Pore Pressure

    NASA Astrophysics Data System (ADS)

    Tinivella, Umberta; Giustiniani, Michela

    2014-05-01

    Many efforts have been devoted to quantify excess pore pressures related to gas hydrate dissociation in marine sediments below the BSR using several approaches. Dissociation of gas hydrates in proximity of the BSR, in response to a change in the physical environment (i.e., temperature and/or pressure regime), can liberate excess gas incrising the local pore fluid pressure in the sediment, so decreasing the effective normal stress. So, gas hydrate dissociation may lead to excess pore pressure resulting in sediment deformation or failure, such as submarine landslides, sediment slumping, pockmarks and mud volcanoes, soft-sediment deformation and giant hummocks. Moreover, excess pore pressure may be the result of gas hydrate dissociation due to continuous sedimentation, tectonic uplift, sea level fall, heating or inhibitor injection. In order to detect the presence of the overpressure below the BSR, we propose two approachs. The fist approach models the BSR depth versus pore pressure; in fact, if the free gas below the BSR is in overpressure condition, the base of the gas hydrate stability is deeper with respect to the hydrostatic case. This effect causes a discrepancy between seismic and theoretical BSR depths. The second approach models the velocities versus gas hydrate and free gas concentrations and pore pressure, considering the approximation of the Biot theory in case of low frequency, i.e. seismic frequency. Knowing the P and S seismic velocity from seismic data analysis, it is possibile to jointly estimate the gas hydrate and free gas concentrations and the pore pressure regime. Alternatively, if the S-wave velocity is not availbale (due to lack of OBS/OBC data), an AVO analysis can be performed in order to extract information about Poisson ratio. Our modeling suggests that the areas characterized by shallow waters (i.e., areas in which human infrastructures, such as pipelines, are present) are significantly affected by the presence of overpressure condition. Moreover, the knoweledge of seismic velocities can be considered an powerful tool to detect the overpressure in case that the pore pressure is equal to the hydrostatic pressure plus the 50% of the difference between the lithostatic and the hydrostatic pressure. In conclusions, an accurate analysis of the BSR nature and the pore pressure are required to improve the reliability of the gas-phase estimation for different target, such as gas hydrate and free gas exploitations and environmental studies.

  13. Complex gas hydrate from the Cascadia margin

    Microsoft Academic Search

    Hailong Lu; Yu-Taek Seo; Jong-Won Lee; Igor Moudrakovski; John A. Ripmeester; N. Ross Chapman; Richard B. Coffin; Graeme Gardner; John Pohlman

    2007-01-01

    Natural gas hydrates are a potential source of energy and may play a role in climate change and geological hazards. Most natural gas hydrate appears to be in the form of `structure I', with methane as the trapped guest molecule, although `structure II' hydrate has also been identified, with guest molecules such as isobutane and propane, as well as lighter

  14. A new high performance gas hydrate inhibitor

    Microsoft Academic Search

    Ehsan Heidaryan; Amir Salarabadi; Jamshid Moghadasi; Alireza Dourbash

    2010-01-01

    In petroleum exploration and production operations, gas hydrates pose serious flow assurance, economic and safety concerns. Thermodynamic inhibitors are widely used to reduce the risks associated with gas hydrate formation. In the present study, systematic laboratory work was undertaken to determine synergistic effects between methanol and a Poly Vinyl Methyl Ether as Low Dosage Hydrate Inhibitors (LDHIs). A valuable effect

  15. Hydration mechanisms of mineral trioxide aggregate

    Microsoft Academic Search

    J. Camilleri

    2007-01-01

    Camilleri J. Hydration mechanisms of mineral trioxide aggre- gate. International Endodontic Journal, 40, 462-470, 2007. Aim To report the hydration mechanism of white mineral trioxide aggregate (White MTA, Dentsply, Tulsa Dental Products, Tulsa, OK, USA). Methodology The chemical constitution of white MTA was studied by viewing the powder in polished sections under the scanning electron microscope (SEM). The hydration of

  16. In-situ characterization of gas hydrates

    Microsoft Academic Search

    T. Moerz; W. Brueckmann; P. Linke; M. Tuerkay

    2003-01-01

    Gas hydrates are a dynamic reservoir in the marine carbon cycle and a periodically large and focussed source of methane probably constituting the largest carbon reservoir on earth. Therefore an important issue in gas hydrate research is the need for better tools to remotely estimate the volume and stability conditions of marine gas hydrate in the near sub-surface. It is

  17. EFFECT OF QUARTZ/MULLITE BLEND CERAMIC ADDITIVE ON IMPROVING RESISTANCE TO ACID OF SODIUM SILICATE-ACTIVATED SLAG CEMENT. CELCIUS BRINE.

    SciTech Connect

    SUGAMA, T.; BROTHERS, L.E.; VAN DE PUTTE, T.R.

    2006-06-01

    We evaluated the usefulness of manufactured quartz/mullite blend (MQMB) ceramic powder in increasing the resistance to acid of sodium silicate-activated slag (SSAS) cementitious material for geothermal wells. A 15-day exposure to 90{sup o} CO{sub 2}-laden H{sub 2}SO{sub 4} revealed that the MQMB had high potential as an acid-resistant additive for SSAS cement. Two factors, the appropriate ratio of slag/MQMB and the autoclave temperature, contributed to better performance of MQMB-modified SSAS cement in abating its acid erosion. The most effective slag/MQMB ratio in minimizing the loss in weight by acid erosion was 70/30 by weight. For autoclave temperature, the loss in weight of 100 C autoclaved cement was a less than 2%, but at 300 C it was even lower. Before exposure to acid, the cement autoclaved at 100 C was essentially amorphous; increasing the temperature to 200 C led to the formation of crystalline analcime in the zeolitic mineral family during reactions between the mullite in MQMB and the Na from sodium silicate. In addition, at 300 C, crystal of calcium silicate hydrate (1) (CSH) was generated in reactions between the quartz in MQMB and the activated slag. These two crystalline phases (CSH and analcime) were responsible for densifying the autoclaved cement, conveying improved compressive strength and minimizing water permeability. The CSH was susceptible to reactions with H{sub 2}SO{sub 4}, forming two corrosion products, bassanite and ionized monosilicic acid. However, the uptake of ionized monosilicic acid by Mg dissociated from the activated slag resulted in the formation of lizardite as magnesium silicate hydrate. On the other hand, the analcime was barely susceptible to acid if at all. Thus, the excellent acid resistance of MQMB-modified SSAS cement was due to the combined phases of lizardite and analcime.

  18. Facile preparation of monodispersed calcium carbonate spherical particles via a simple precipitation reaction

    Microsoft Academic Search

    Jiaguo Yu; Ming Lei; Bei Cheng

    2004-01-01

    Monodispersed calcium carbonate spherical particles with a size of about 1–2?m could be prepared by a precipitation reaction of sodium carbonate with calcium chloride in the presence of polymaleicanhydride (PMA) or poly (sodium 4-styene-sulfonate) (PSSS) at room temperature. The as-prepared products were characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry–thermogravimetry (DSC–TG). It was found that

  19. Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension

    NASA Technical Reports Server (NTRS)

    Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

  20. Calcium and nitrogen balance, experiment M007

    NASA Technical Reports Server (NTRS)

    Whedon, G. D.; Lutwak, L.; Neuman, W. F.; Lachance, P. A.

    1971-01-01

    The collection of data on the response of the skeletal and muscular systems to 14-day space flights was evaluated for loss of calcium, nitrogen, and other metabolically related elements. Considerable interindividual variability was demonstrated in all experimental factors that were measured. Calcium balance became less positive and urinary phosphate excretion increased substantially in flight despite a reduction in phosphate intake. Patterns of excretion of magnesium, sodium, potassium, and chloride were different for each subject, and, in part, could be correlated with changes in adrenocortical steroid production. The principal hormonal change was a striking decrease during flight in the urinary excretion of 17-hydroxycortocosteroids. Dermal losses of calcium, magnesium, sulfate, and phosphate were insignificant during all three phases.

  1. Investigation of high-reactivity calcium carbonate sorbent for enhanced SOâ capture

    Microsoft Academic Search

    Abhijit Ghosh-Dastidar; Suhas K. Mahuli; Rajeev Agnihotri; Liang-Shih Fan

    1996-01-01

    Kinetics of ultrafast, high-temperature sulfation is investigated for two calcium carbonates from different sources, a commercial calcium hydroxide and a laboratory-made modified hydrated lime powder. Time-resolved kinetic data are obtained for a 0--600 ms time scale at a temperature of 1,080 C with in-situ particle size classification. A mean particle size of 3.9 μm is considered for sorbent comparison studies.

  2. Distribution of calcium in the stigma and style of tobacco during pollen germination and tube elongation

    Microsoft Academic Search

    Li Li Ge; Chao Tian Xie; Hui Qiao Tian; Scott D. Russell

    2009-01-01

    Potassium antimonate was used to locate loosely bound calcium in the stigma and style of tobacco. The tobacco stigma is wet\\u000a and covered by a thick layer of glycoprotein exudate at anthesis. The exudate contains abundant vesicles, which are densely\\u000a labeled with calcium precipitates. When pollen grains arrive at the stigma, become hydrated, and as the pollen swells, Ca2+ precipitates

  3. L-type calcium channel activation up-regulates the mRNAs for two different sodium channel alpha subunits (Nav1.2 and Nav1.3) in rat pituitary GH3 cells.

    PubMed

    Vega, Ana Victoria; Espinosa, Juan Luis; López-Domínguez, Adriana M; López-Santiago, Luis Félix; Navarrete, Araceli; Cota, Gabriel

    2003-08-19

    Calcium entry through L-type Ca2+ channels has been shown to increase the number of Na+ channels in GH3 cells, a clonal line of rat pituitary cells. To test whether this Ca2+ influx affects the levels of Na+ channel mRNAs, we first examined which Na+ channel subunits are expressed in GH3 cells. By using RT-PCR with specific primers, we detected transcripts for four alpha subunits (Nav1.1, Nav1.2, Nav1.3 and Nav1.6) and two auxiliary subunits (beta1 and beta3) of Na+ channels in total RNA from control GH3 cells. Next, we optimized the RT-PCR conditions to allow detection of cDNAs in the linear range of the assay. These conditions were then used to assess the transcript levels of Na+ channels after chronic exposure (72 h) of GH3 cells to the L-type Ca2+ channel blocker nimodipine (1 microM) or the L-type channel agonist Bay K 8644 (0.5 microM). Nimodipine treatment caused a moderate reduction (approximately 30%) of the mRNA for Nav1.2 and a marked reduction (approximately 70%) of the mRNA for Nav1.3, whereas treatment with Bay K 8644 produced 90-130% increases in these same mRNAs. There were no concomitant changes in the mRNAs for Nav1.1 and Nav1.6. Moreover, beta1 and beta3 mRNA levels were also unchanged. Thus, GH3 cells express multiple Na+ channel subunits and L-type Ca2+ channel activity up-regulates in a specific way the mRNAs for Nav1.2 and Nav1.3. These findings improve our knowledge on the molecular diversity of Na+ channels in pituitary cells and extend the actual view about the regulation of Na+ channel gene expression by Ca2+ influx. PMID:12941467

  4. SLAM: a sodium-limestone concrete ablation model

    SciTech Connect

    Suo-Anttila, A.J.

    1983-12-01

    SLAM is a three-region model, containing a pool (sodium and reaction debris) region, a dry (boundary layer and dehydrated concrete) region, and a wet (hydrated concrete) region. The model includes a solution to the mass, momentum, and energy equations in each region. A chemical kinetics model is included to provide heat sources due to chemical reactions between the sodium and the concrete. Both isolated model as well as integrated whole code evaluations have been made with good results. The chemical kinetics and water migration models were evaluated separately, with good results. Several small and large-scale sodium limestone concrete experiments were simulated with reasonable agreement between SLAM and the experimental results. The SLAM code was applied to investigate the effects of mixing, pool temperature, pool depth and fluidization. All these phenomena were found to be of significance in the predicted response of the sodium concrete interaction. Pool fluidization is predicted to be the most important variable in large scale interactions.

  5. Attraction between hydrated hydrophilic surfaces

    NASA Astrophysics Data System (ADS)

    Kandu?, Matej; Schneck, Emanuel; Netz, Roland R.

    2014-08-01

    According to common knowledge, hydrophilic surfaces repel via hydration forces while hydrophobic surfaces attract, but mounting experimental evidence suggests that also hydrophilic surfaces can attract. Using all-atom molecular dynamics simulations at prescribed water chemical potential we study the crossover from hydration repulsion to hydrophobic attraction for planar polar surfaces of varying stiffness and hydrogen-bonding capability. Rescaling the partial charges of the polar surface groups, we cover the complete spectrum from very hydrophobic surfaces (characterized by contact angles ? ? 135°) to hydrophilic surfaces exhibiting complete wetting (? = 0°). Indeed, for a finite range ?adh < ? < 90°, we find a regime where hydrophilic surfaces attract at sub-nanometer separation and stably adhere without intervening water. The adhesive contact angle ?adh depends on surface type and lies in the range 65° < ?adh < 80°, in good agreement with experiments. Analysis of the total number of hydrogen bonds (HBs) formed by water and surface groups rationalizes this crossover between hydration repulsion and hydrophilic attraction in terms of a subtle balance: Highly polar surfaces repel because of strongly bound hydration water, less polar hydrophilic surfaces attract because water-water HBs are preferred over surface-water HBs. Such solvent reorganization forces presumably underlie also other important phenomena, such as selective ion adsorption to interfaces as well as ion pair formation.

  6. Hydration rind dates rhyolite flows

    USGS Publications Warehouse

    Friedman, I.

    1968-01-01

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago.

  7. Hydration rind dates rhyolite flows.

    PubMed

    Friedman, I

    1968-02-23

    Hydration of obsidian has been used to date rhyolite flows, containing obsidian or porphyritic glass, at Glass Mountain (Medicine Lake Highlands) and Mono Lake, California. The method is simple and rapid and can be used to date flows that erupted between 200 and approximately 200,000 years ago. PMID:17768978

  8. A model system for assessing physicochemical factors affecting calcium absorbability from the intestinal tract.

    PubMed

    Pak, C Y; Poindexter, J; Finlayson, B

    1989-02-01

    An in vitro model system was utilized to critically examine physicochemical factors that could play a role in determining the amount of potentially absorbable ionic calcium as well as soluble complexes in the proximal jejunum following ingestion of tricalcium dicitrate, calcium carbonate, or tricalcium diphosphate. The solubility of calcium salts (500 mg calcium each) was tested in 300 ml water containing varying amounts of hydrochloric acid (0, 0.72, 2.4, 7.26, and 24.2 mEq) intended to mimic achlorhydric to peak acid secretory states. Whereas 20% of calcium citrate dissolved in the absence of hydrochloric acid, a negligible amount of calcium carbonate and calcium phosphate underwent dissolution. In solutions containing 0.72-7.26 mEq hydrochloric acid, calcium citrate was more than twofold soluble than calcium carbonate, and calcium phosphate had intermediate solubility. At simulated peak acid secretion, all three salts were completely soluble, or nearly so. To simulate pancreatic bicarbonate secretion, the filtrates obtained from solubility studies were titrated to pH 5, 6, and 7 with sodium hydroxide. Reprecipitation of calcium citrate and calcium carbonate did not occur. However, substantial calcium phosphate reprecipitation took place especially at high pH and in filtrates derived from high hydrochloric acid content. In filtrates derived from reprecipitation experiments (at pH 6 and 7), anionic complexation of calcium was calculated in order to estimate the amount of ionic and complexed calcium. Considerable amount of calcium from dissolved calcium citrate was complexed (60-65%), principally as soluble CaCit-, whereas calcium complexation was negligible in the calcium carbonate and calcium phosphate systems. PMID:2718774

  9. Gemini near-infrared observations of Europa's Hydrated Surface Materials

    NASA Astrophysics Data System (ADS)

    Tsang, C.; Spencer, J. R.; Grundy, W. M.; Dalton, J. B.

    2012-12-01

    Europa is a highly dynamic icy moon of Jupiter. It is thought the moon harbors a subsurface ocean, with the potential to sustain life, with Europa being a key target of ESA's forthcoming Jupiter Icy Moons Orbiter (JUICE) mission. However, much is not known concerning the chemistry of the subsurface ocean. The surface is dominated by water ice, with a hydrated non-ice material component providing the distinctive albedo contrasts seen at visible and near-infrared wavelengths. These non-ice materials are concentrated at disrupted surface regions, providing a diagnostic probe for the chemistry and characteristics of the liquid ocean beneath. Leading but potentially competing theories on the composition of these hydrated non-ice materials suggest either sulfuric acid-water mixtures (Carlson et al., 1999) or hydrated magnesium/sodium salts (McCord et al., 1999). Recent reanalysis of Galileo-NIMS observations suggest a mixture of both - hydrated salts are present at all longitudes but the sulfuric acid hydrates are localized on the trailing side. We present preliminary analysis of new ground-based Gemini disk-resolved spectroscopy of Europa using the Near-Infrared Integrated Field Spectrometer (NIFS), taken in late 2011, at H (1.49 - 1.80 ?m) and K bands (1.99 - 2.40 ?m) with spectral resolving powers of ~ 5300. At these NIR wavelengths, with spectral resolution much better than Galileo-NIMS, the spectral absorption and continuum characteristics of these ice and non-ice materials can be separated out. In addition, the spatial resolution potentially allows identification of localized materials whose signature would be diluted in disk-integrated spectra. These observations of the trailing hemisphere use Altair adaptive optics to achieve spatial resolutions of 0.1" (~310 km per pixel) or better, potentially leading to better identification of the non-ice materials and their spatial distributions. References Carlson, R.W., R.E. Johnson, and M.S. Anderson 1999. Sulfuric acid on Europa and the radiolytic sulfur cycle. Science 286, 97-99. McCord, T. et al. 1999. Hydrated salt minerals on Europa's surface from the Galileo Near- Infrared Mapping Spectrometer (NIMS) investigation. J. Geophys. Res. 104, 11827

  10. Environ. Scl. Technol. 1994, 28, 277-283 Effects of Salts on Preparation and Use of Calcium Silicates for Flue Gas

    E-print Network

    Rochelle, Gary T.

    to remove sulfur dioxide. High surface area calcium silicate hydrates are made by slurrying Ca(0HEnviron. Scl. Technol. 1994, 28, 277-283 Effects of Salts on Preparation and Use of Calcium Silicates for Flue Gas Desulfurization Kurt K. Klnd, Phlllp D. Wasserman, and Gary 1.Rochelle' Department

  11. Effect of Base Sequence and Hydration on the Electronic and Hole Transport Properties of Duplex DNA: Theory and Experiment

    NASA Astrophysics Data System (ADS)

    Barnett, Robert N.; Cleveland, Charles L.; Landman, Uzi; Boone, Edna; Kanvah, Sriram; Schuster, Gary B.

    2003-03-01

    An experimental investigation and theoretical study of the duplex DNA sequences d(5'-GAGG-3')d(3'-CTCC-5') and d(5'-GTGG-3')d(3'-CACC-5') was carried out. The experiments show that the efficiency of radical cation transport, revealed by strand cleavage after treatment with piperidine, is the same in both sequences. DFT calculations reveal essentially identical ionization potentials and hole distributions for these sequences when they are properly hydrated. The effect of hydration on the electronic properties of these sequences was examined theoretically. Calculations on "dry" DNA (i.e., having no water molecules) gives "phantom" electronic transitions to orbitals associated with the sodium counterions. However, these transitions vanish even with a minimal level of hydration. Meaningful theoretical results for DNA are obtained only when the counterions and hydrating water molecules are properly considered.

  12. Regulation of airway mucosal hydration.

    PubMed

    Paisley, Derek; Gosling, Martin; Danahay, Henry

    2010-05-01

    Ion channels control the hydration status of the airway epithelium through apical anion secretion and cation absorption, which is accompanied by osmotically obligated water. The key channels in this process are the cystic fibrosis (CF) transmembrane conductance regulator (CFTR), which is principally responsible for Cl(-) secretion by airway epithelial cells, and the epithelial Na(+) channel (ENaC), which is responsible for the absorption of Na ions. In CF, defective CFTR-mediated Cl(-) secretion and an accompanying upregulation in ENaC-mediated Na absorption results in a reduction in airway surface liquid volume, leading to poorly hydrated mucus and impaired mucociliary clearance. Restoration of normal airway hydration by modulation of ion channel activity represents an important therapeutic strategy for CF. CFTR corrector and potentiator compounds are being developed with the aim of recovering normal Cl(-) secretion. Ca(2+)-activated Cl(-) channels (CaCCs) are expressed by the respiratory epithelia and are reported to be functionally upregulated in CF and offer a 'surrogate' pathway for Cl(-) secretion. TMEM16A has recently been described as a CaCC in the airway epithelium and, as such, represents an alternative target for restoring Cl(-) secretion in CF. An alternative therapeutic strategy for CF is to inhibit ENaC, thereby blocking excessive Na absorption. This can be achieved by direct blockade of ENaC or inhibition of the channel-activating proteases (CAPs), whose activity regulates ENaC function. This review will describe the regulation of airway mucosal hydration by ion channels and the efforts currently underway to restore normal mucosal hydration in disease patients by modulating the function of these channels. PMID:22111616

  13. Physical activity, hydration and health.

    PubMed

    Marcos, Ascensión; Manonelles, Pedro; Palacios, Nieves; Wärnberg, Julia; Casajús, José A; Pérez, Margarita; Aznar, Susana; Benito, Pedro J; Martínez-Gomez, David; Ortega, Francisco B; Ortega, Eduardo; Urrialde, Rafael

    2014-01-01

    Since the beginning of mankind, man has sought ways to promote and preserve health as well as to prevent disease. Hydration, physical activity and exercise are key factors for enhancing human health. However, either a little dose of them or an excess can be harmful for health maintenance at any age. Water is an essential nutrient for human body and a major key to survival has been to prevent dehydration. However, there is still a general controversy regarding the necessary amount to drink water or other beverages to properly get an adequate level of hydration. In addition, up to now the tools used to measure hydration are controversial. To this end, there are several important groups of variables to take into account such as water balance, hydration biomarkers and total body water. A combination of methods will be the most preferred tool to find out any risk or situation of dehydration at any age range. On the other hand, physical activity and exercise are being demonstrated to promote health, avoiding or reducing health problems, vascular and inflammatory disea ses and helping weight management. Therefore, physical activity is also being used as a pill within a therapy to promote health and reduce risk diseases, but as in the case of drugs, dose, intensity, frequency, duration and precautions have to be evaluated and taken into account in order to get the maximum effectiveness and success of a treatment. On the other hand, sedentariness is the opposite concept to physical activity that has been recently recognized as an important factor of lifestyle involved in the obesogenic environment and consequently in the risk of the non-communicable diseases. In view of the literature consulted and taking into account the expertise of the authors, in this review a Decalogue of global recommendations is included to achieve an adequate hydration and physical activity status to avoid overweight/obesity consequences. PMID:24972459

  14. CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, CALCIUM CHLORIDE STORAGE BUILDING ON RIGHT WITH SA (SODA ASH) BUILDING IN RIGHT BACKGROUND. - Solvay Process Company, Calcium Chloride Plant, Between Willis & Milton Avenues, Solvay, Onondaga County, NY

  15. A new antacid drug from activated carbon modified with calcium carbonate

    Microsoft Academic Search

    Carlos F. Linares; José Quintero; Lesbia Martínez; Gema González

    2007-01-01

    Activated carbons were previously modified with different sodium carbonate solutions and then, they were soaked in a calcium nitrate solution. This procedure allowed to precipitate calcium carbonate on the microporous carbons. Then, these solids were washed with abundant distillated water. These modified carbons were characterized by means of XRD, SEM, HRTEM and BET surface area measurements. XRD confirmed the presence

  16. Calcium carbonate inhibition by a phosphonate-terminated poly(maleic-co-sulfonate) polymeric inhibitor

    Microsoft Academic Search

    Chen Wang; Shu-ping Li; Tian-duo Li

    2009-01-01

    The precipitation of calcium carbonate scale on heat transfer surfaces widely occurs in numerous industrial processes. For the control of calcium carbonate scale and in response to environmental guidelines, the new low phosphonic copolymer was prepared through reaction of maleic anhydride with sodium p-styrene sulfonate in water with redox system of hypophosphorous and hydrogen peroxide as initiator. The anti-scale property

  17. Effects on ionized calcium of a correction of acidosis with alkalinizing agents. A rational basis for the administration of calcium in cardiac resuscitation.

    PubMed

    Schaer, H

    1976-04-01

    The effects on the ionized calcium concentration of a correction of various forms of acidosis with sodium bicarbonate or (tris-hydroxymethyl)aminomethane (THAM) were investigated in vitro in human plasma. Calculation of least square regression equations of ionized calcium (m mol) on pH yielded the following regression coefficients: hydrochloric acidosis: -0.65 +/- 0.06; lactic acidosis: -0.27 +/- 0.05; hydrochloric acidosis corrected with sodium bicarbonate: -0.65 +/- 0.02; lactic acidosis corrected with sodium bicarbonate: -0.51 +/- 0.03. The results indicate that after correction of lactic acidosis the ionized calcium concentration will be below the control values while pH is restored to the normal range. This effect is even more pronounced when THAM is used. The findings point to the need for calcium administration in cardiac resuscitation. PMID:1275999

  18. Handbook of gas hydrate properties and occurrence

    SciTech Connect

    Kuustraa, V.A.; Hammershaimb, E.C.

    1983-12-01

    This handbook provides data on the resource potential of naturally occurring hydrates, the properties that are needed to evaluate their recovery, and their production potential. The first two chapters give data on the naturally occurring hydrate potential by reviewing published resource estimates and the known and inferred occurrences. The third and fourth chapters review the physical and thermodynamic properties of hydrates, respectively. The thermodynamic properties of hydrates that are discussed include dissociation energies and a simplified method to calculate them; phase diagrams for simple and multi-component gases; the thermal conductivity; and the kinetics of hydrate dissociation. The final chapter evaluates the net energy balance of recovering hydrates and shows that a substantial positive energy balance can theoretically be achieved. The Appendices of the Handbook summarize physical and thermodynamic properties of gases, liquids and solids that can be used in designing and evaluating recovery processes of hydrates. 158 references, 67 figures, 47 tables.

  19. Recent Insights into the Structure and Mechanism of the Sodium Pump

    NSDL National Science Digital Library

    J. -D. Horisberger (University of Lausanne Department of Pharmacology and Toxicology)

    2004-12-01

    The sodium pump (or Na-K-ATPase) is essential to the function of animal cells. Publication of the related calcium pump (SERCA) structure together with several recent results from a variety of approaches allow us to propose a mechanistic model to answer the question: "How does the sodium pump pump?"

  20. Mycorrhizal weathering of apatite as an important calcium source in base-poor forest ecosystems.

    PubMed

    Blum, Joel D; Klaue, Andrea; Nezat, Carmen A; Driscoll, Charles T; Johnson, Chris E; Siccama, Thomas G; Eagar, Christopher; Fahey, Timothy J; Likens, Gene E

    2002-06-13

    The depletion of calcium in forest ecosystems of the northeastern USA is thought to be a consequence of acidic deposition and to be at present restricting the recovery of forest and aquatic systems now that acidic deposition itself is declining. This depletion of calcium has been inferred from studies showing that sources of calcium in forest ecosystems namely, atmospheric deposition and mineral weathering of silicate rocks such as plagioclase, a calcium-sodium silicate do not match calcium outputs observed in forest streams. It is therefore thought that calcium is being lost from exchangeable and organically bound calcium in forest soils. Here we investigate the sources of calcium in the Hubbard Brook experimental forest, through analysis of calcium and strontium abundances and strontium isotope ratios within various soil, vegetation and hydrological pools. We show that the dissolution of apatite (calcium phosphate) represents a source of calcium that is comparable in size to known inputs from atmospheric sources and silicate weathering. Moreover, apatite-derived calcium was utilized largely by ectomycorrhizal tree species, suggesting that mycorrhizae may weather apatite and absorb the released ions directly, without the ions entering the exchangeable soil pool. Therefore, it seems that apatite weathering can compensate for some of the calcium lost from base-poor ecosystems, and should be considered when estimating soil acidification impacts and calcium cycling. PMID:12066181

  1. Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution

    NASA Astrophysics Data System (ADS)

    Sultan, N.; Bohrmann, G.; Ruffine, L.; Pape, T.; Riboulot, V.; Colliat, J.-L.; De Prunelé, A.; Dennielou, B.; Garziglia, S.; Himmler, T.; Marsset, T.; Peters, C. A.; Rabiu, A.; Wei, J.

    2014-04-01

    In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate-bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of free gas and gas hydrate indicate rapid hydrate growth. On the other hand, slow hydrate dissolution is evident by low methane concentrations and almost constant sulfate values 2 m above the Gas Hydrate Occurrence Zone.

  2. Thermal conductivity of hydrate-bearing sediments

    USGS Publications Warehouse

    Cortes, D.D.; Martin, A.I.; Yun, T.S.; Francisca, F.M.; Santamarina, J.C.; Ruppel, C.

    2009-01-01

    A thorough understanding of the thermal conductivity of hydrate-bearing sediments is necessary for evaluating phase transformation processes that would accompany energy production from gas hydrate deposits and for estimating regional heat flow based on the observed depth to the base of the gas hydrate stability zone. The coexistence of multiple phases (gas hydrate, liquid and gas pore fill, and solid sediment grains) and their complex spatial arrangement hinder the a priori prediction of the thermal conductivity of hydrate-bearing sediments. Previous studies have been unable to capture the full parameter space covered by variations in grain size, specific surface, degree of saturation, nature of pore filling material, and effective stress for hydrate-bearing samples. Here we report on systematic measurements of the thermal conductivity of air dry, water- and tetrohydrofuran (THF)-saturated, and THF hydrate-saturated sand and clay samples at vertical effective stress of 0.05 to 1 MPa (corresponding to depths as great as 100 m below seafloor). Results reveal that the bulk thermal conductivity of the samples in every case reflects a complex interplay among particle size, effective stress, porosity, and fluid-versus-hydrate filled pore spaces. The thermal conductivity of THF hydrate-bearing soils increases upon hydrate formation although the thermal conductivities of THF solution and THF hydrate are almost the same. Several mechanisms can contribute to this effect including cryogenic suction during hydrate crystal growth and the ensuing porosity reduction in the surrounding sediment, increased mean effective stress due to hydrate formation under zero lateral strain conditions, and decreased interface thermal impedance as grain-liquid interfaces are transformed into grain-hydrate interfaces. Copyright 2009 by the American Geophysical Union.

  3. Discordant effects of glucocorticoids on active and passive transport of calcium in the rat duodenum

    Microsoft Academic Search

    John F. Aloia; Halina M. Semla; James K. Yeh

    1984-01-01

    Summary  The effect of glucocorticoids on duodenal active and passive calcium transport was studied by thein situ intestinal loop technique, using 2.0 mM and 50 mM concentrations of calcium. The administration of prednisolone resulted\\u000a in a significant increase of fluid and sodium absorption. The final luminal calcium concentration was increased in the prednisolone-treated\\u000a group. Under conditions where active transport predominates (2

  4. Hydrated calcareous oil-shale ash as potential filter media for phosphorus removal in constructed wetlands.

    PubMed

    Kaasik, Ago; Vohla, Christina; Mõtlep, Riho; Mander, Ulo; Kirsimäe, Kalle

    2008-02-01

    The P-retention in hydrated calcareous ash sediment from oil-shale burning thermal power plants in Estonia was studied. Batch experiments indicate good (up to 65 mg P g(-1)) P-binding capacity of the hydrated oil-shale ash sediment, with a removal effectiveness of 67-85%. The high phosphorus sorption potential of hydrated oil-shale ash is considered to be due to the high content of reactive Ca-minerals, of which ettringite Ca6Al2(SO4)3(OH)12.26H2O and portlandite Ca(OH)2 are the most important. The equilibrium dissolution of ettringite provides free calcium ions that act as stable nuclei for phosphate precipitation. The precipitation mechanism of phosphorus removal in hydrated ash plateau sediment is suggested by Ca-phosphate formation in batch experiments at different P-loadings. Treatment with a P-containing solution causes partial-to-complete dissolution of ettringite and portlandite, and precipitation of Ca-carbonate and Ca-phosphate phases, which was confirmed by X-ray diffraction (XRD) and scanning electron microscope (SEM)-EDS studies. Thus, the hydrated oil-shale ash sediment can be considered as a potential filtration material for P removal in constructed wetlands for wastewater treatment. PMID:17959214

  5. Adenine Dinucleotide Second Messengers and T-lymphocyte Calcium Signaling

    PubMed Central

    Ernst, Insa M. A.; Fliegert, Ralf; Guse, Andreas H.

    2013-01-01

    Calcium signaling is a universal signal transduction mechanism in animal and plant cells. In mammalian T-lymphocytes calcium signaling is essential for activation and re-activation and thus important for a functional immune response. Since many years it has been known that both calcium release from intracellular stores and calcium entry via plasma membrane calcium channels are involved in shaping spatio-temporal calcium signals. Second messengers derived from the adenine dinucleotides NAD and NADP have been implicated in T cell calcium signaling. Nicotinic acid adenine dinucleotide phosphate (NAADP) acts as a very early second messenger upon T cell receptor/CD3 engagement, while cyclic ADP-ribose (cADPR) is mainly involved in sustained partial depletion of the endoplasmic reticulum by stimulating calcium release via ryanodine receptors. Finally, adenosine diphosphoribose (ADPR) a breakdown product of both NAD and cADPR activates a plasma membrane cation channel termed TRPM2 thereby facilitating calcium (and sodium) entry into T cells. Receptor-mediated formation, metabolism, and mode of action of these novel second messengers in T-lymphocytes will be reviewed. PMID:24009611

  6. The 2003 heat wave in France: hydratation status changes in older inpatients

    Microsoft Academic Search

    Adrien Kettaneh; Laurence Fardet; Nathalie Mario; Aurelia Retbi; Namik Taright; Kiet Tiev; Ingrid Reinhard; Bertrand Guidet; Jean Cabane

    2010-01-01

    Little is known about the impact of behavioral changes after the 2003 heat wave on hydration status of elderly citizens in\\u000a France. We used an administrative data file provided information about 23,022 inpatients aged ?70 years admitted between 2000\\u000a and 2006, including vital status at discharge and Charlson comorbidity index and matched it with the result of five blood\\u000a tests (sodium,

  7. Dynamics of a membrane-bound tryptophan analog in environments of varying hydration: a fluorescence approach

    Microsoft Academic Search

    Amitabha Chattopadhyay; Ajuna Arora; Devaki A. Kelkar

    2005-01-01

    Tryptophan octyl ester (TOE) represents an important model for membrane-bound tryptophan residues. In this article, we have employed a combination of wavelength-selective fluorescence and time-resolved fluorescence spectroscopies to monitor the effect of varying degrees of hydration on the dynamics of TOE in reverse micellar environments formed by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in isooctane. Our results show that TOE exhibits red

  8. Relative bioavailability of calcium from calcium formate, calcium citrate, and calcium carbonate

    E-print Network

    Hanzlik, Robert P.; Fowler, S. C.; Fisher, D. H.

    2005-06-01

    Published Abstract: Calcium is an essential nutrient required in substantial amounts, but many diets are deficient in calcium making supplementation necessary or desirable. The objective of this study was to compare the oral bioavailability...

  9. Calcium and Your Child

    MedlinePLUS

    ... t overlook other healthy calcium-fortified foods, including orange juice, soy products, and bread. Here are some ... 300 milligrams 8 ounces (237 milliliters) calcium-fortified orange juice 300 milligrams 2 ounces (57 grams) American ...

  10. Calcium in diet

    MedlinePLUS

    ... Salmon and sardines canned with their soft bones Almonds, Brazil nuts, sunflower seeds, tahini, and dried beans ... greens = 220 mg of calcium 3 ounces of almonds = 210 mg of calcium Vitamin D is needed ...

  11. Sodium: Tips for People with Chronic Kidney Disease (CKD)

    MedlinePLUS

    ... Daily Value* Total Fat 13g 20 % Saturated Fat 5g 25 % Trans Fat 2g Cholesterol 30mg 10 % Sodium ... Carbohydrate 31g 10% Dietary Fiber 0g 0 % Sugars 5g Protein 5g VitaminA4% • Calcium 15% • * Percent Daily Values ...

  12. 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.

  13. Calcium absorption and achlorhydria

    Microsoft Academic Search

    Robert R. Recker

    1985-01-01

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium

  14. 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

  15. Characterization of a novel calcium phosphate composite bone cement: flow, setting, and aging properties.

    PubMed

    Roemhildt, M L; Wagner, S D; McGee, T D

    2006-11-01

    The flow, setting, and aging characteristics of a newly developed calcium phosphate/calcium aluminate composite orthopaedic cement were studied. The effect of vibration on the flow of the cement paste was studied and found to greatly enhance placement. The setting times of this cement were dependent on temperature and decreased with increasing temperatures. At 37 degrees C, the working and setting times were 6.3 +/- 0.3 and 12.8 +/- 0.4 minutes, respectively. Hydration and conversion of the cement phases continued while specimens were stored under simulated, physiological conditions. A cumulative increase in mass of 8.23 +/- 0.65% was observed over a 14 month test period. During this time, the cement was found to expand slightly, 0.71 +/- 0.39%. X-ray diffraction was used to characterize the crystalline phases present during hydration and conversion. The calcium aluminate in the cement hydrated and formed calcium aluminate chloride hydrates, while no changes were observed in the beta-tricalcium phosphate during the testing period. PMID:17122927

  16. SIMULTANEOUS CONTROL OF HG(0), SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    EPA Science Inventory

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). {NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents ...

  17. SIMULTANEOUS CONTROL OF HGO, SO2, AND NOX BY NOVEL OXIDIZED CALCIUM-BASED SORBENTS

    EPA Science Inventory

    The paper gives results of an investigation of two classes of calcium (Ca)-based sorbents (hydrated limes and silicate compounds). (NOTE: Efforts to develop multipollutant control strategies have demonstrated that adding certain oxidants to different classes of Ca-based sorbents...

  18. Sodium carbonate poisoning

    MedlinePLUS

    Sodium carbonate (also known as washing soda or soda ash) is a chemical found in many household and ... products. This article focuses on poisoning due to sodium carbonate. This is for information only and not for ...

  19. Sodium in Drinking Water

    MedlinePLUS

    ... To reduce my sodium intake, should I buy bottled water instead of using tap water? For more information. ... To reduce my sodium intake, should I buy bottled water instead of using tap water? It is not ...

  20. Sodium blood test

    MedlinePLUS

    ... of diuretics, or burns Too much salt or sodium bicarbonate in the diet Use of certain medicines, including birth control pills, corticosteroids, laxatives, lithium, and ... than normal sodium level is called hyponatremia. It may be due ...