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1

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

2

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.  

Code of Federal Regulations, 2013 CFR

...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...

2013-04-01

3

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

PubMed

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

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

1988-02-01

4

Effect of compounding of sodium tripolyphosphate and super plasticizers on the hydration of ?-calcium sulfate hemihydrate  

Microsoft Academic Search

The inhibition and its mechanism of sodium tripolyphosphate (STP) composited with super plasticizers (SPs) on hydration of\\u000a ?-calcium sulfate hemihydrate were studied by setting time, strength, hydration heat, X-ray diffraction (XRD), X-ray photoelectron\\u000a spectroscopy (XPS), electronic probe micro analysis (EPMA), scanning electron microscopy (SEM) and differential scanning calorimeter\\u000a (DSC) measurements. The experimental results show that compared with STP addition, compositing

Wei Pan; Peiming Wang

2011-01-01

5

The protective effect of hydrated sodium calcium aluminosilicate against haematological, biochemical and pathological changes induced by Zearalenone in mice  

Microsoft Academic Search

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added alone or simultaneously with a toxic Zearalenone (ZEN) dose to balb\\/c mice and was evaluated for its ability to restore damages induced by ZEN. The latter is a mycotoxin produced by fusarium genera; it is mainly known to induce several toxic effects such as hepatotoxicity, immunotoxicity and

Samir Abbs; Zouhour Ouanes; Jalila ben Salah-Abbs; Zohra Houas; Ridha Oueslati; Hassen Bacha; Omar Othman

2006-01-01

6

Diminution of aflatoxin toxicity to growing lambs by dietary supplementation with hydrated sodium calcium aluminosilicate.  

PubMed

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing wethers (mean body weight, 34.0 kg) and was evaluated for its ability to diminish the clinical signs of aflatoxicosis. The experimental design consisted of 4 treatment groups of 5 wethers each, consuming concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control; group 1); 20 g of HSCAS/kg (2.0%; group 2), 2.6 mg of AF/kg (group 3); or 20 g of HSCAS (2.0%) plus 2.6 mg of AF/kg (group 4). Wethers were maintained in indoor pens, with feed and water available ad libitum for 42 days. Lambs were observed twice daily and weighed weekly, and blood samples were obtained every 2 weeks for hematologic and serum biochemical analyses and for measurement of mitogen-induced lymphocyte-stimulation index. At the termination of the study, wethers were euthanatized and necropsied. Body weight gain was diminished significantly (P less than 0.05) by consumption of 2.6 mg of AF/kg of feed, whereas body weight of lambs consuming HSCAS plus AF did not differ from that of control wethers. The AF-alone treatment increased serum aspartate transaminase and gamma-glutamyltransferase activities, prothrombin time, and cholesterol, uric acid, and triglyceride values and decreased albumin, glucose, and urea nitrogen values, and urea-to-creatine ratio.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1850585

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

1991-01-01

7

Prevention of aflatoxicosis by addition of hydrated sodium calcium aluminosilicate to the diets of growing barrows.  

PubMed

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing barrows and was evaluated for its potential to ameliorate the clinical signs of aflatoxicosis. The experimental design consisted of 6 treatments of 5 barrows each at concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control), 5 g of HSCAS/kg of feed (0.5%), 20 g of HSCAS/kg of feed (2.0%), 3 mg of AF/kg of feed, 5 g of HSCAS (0.5%) plus 3 mg of AF/kg of feed, or 20 g of HSCAS (2.0%) plus 3 mg of AF/kg of feed. Barrows were maintained in indoor concrete-floored pens, with feed and water available ad libitum for 28 days (from the age of 7 to 11 weeks). Barrows were observed twice daily and were weighed weekly, and blood samples were obtained weekly for hematologic and serum biochemical measurements. At the termination of the study, barrows were euthanatized and necropsied. Body weight gains were diminished significantly (P less than 0.05) by consumption of 3 mg of AF/kg of feed, whereas body weight gain in barrows consuming diets containing HSCAS or HSCAS plus AF did not differ from that in control barrows. Serum enzymatic activities of alkaline phosphatase and gamma-glutamyl transferase and prothrombin time were increased in barrows consuming 3 mg of AF/kg of feed, but not in those consuming HSCAS or HSCAS plus AF.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2562791

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

1989-03-01

8

The protective effect of hydrated sodium calcium aluminosilicate against haematological, biochemical and pathological changes induced by Zearalenone in mice.  

PubMed

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added alone or simultaneously with a toxic Zearalenone (ZEN) dose to balb/c mice and was evaluated for its ability to restore damages induced by ZEN. The latter is a mycotoxin produced by fusarium genera; it is mainly known to induce several toxic effects such as hepatotoxicity, immunotoxicity and nephrotoxicity on animals and humans. The experimental approach consisted of eight treatments of six mice each by 400 mg/kg bw or 5 g/kg bw of HSCAS. Two experimental groups have received respectively ZEN alone at 40 (8% of LD50) and at 500 mg/kg bw (LD50). Two other groups have received ZEN at 40 or 500 mg/kg bw combined respectively with HSCAS at 400 mg/kg bw and 5 g/kg bw. The control groups received water or olive oil. Forty-eight hours after treatment, blood samples were collected for haematological and serum biochemical parameters measurements. ZEN treatment significantly increased hematocrit, haemoglobin, white blood cells: lymphocytes, eosinophils, neutrophils, monocytes and the most of biochemical serum parameters; it significantly reduced platelets and induced degenerative changes in the hepatic and renal tissues; while, the mixture of HSCAS with ZEN induced a reestablishment of haematological parameters, levels of serum biochemical enzyme activities and histological pictures of both liver and kidney. It also prevented general toxicity of ZEN. This was observed by the shift of LD50 for this toxin. Thus, our data strongly suggested that deleterious effects of ZEN could be overcome or, at least, significantly were diminished by HSCAS. Moreover, this sorbent by itself did not show any toxic effects. PMID:16563452

Abbs, Samir; Ouanes, Zouhour; ben Salah-Abbs, Jalila; Houas, Zohra; Oueslati, Ridha; Bacha, Hassen; Othman, Omar

2006-03-24

9

Hydration of calcium sulfate hemihydrate (CaSO 4 1 2 H 2O) into gypsum (CaSO 42H 2O). The influence of the sodium poly(acrylate)\\/surface interaction and molecular weight  

Microsoft Academic Search

The retarding influence of sodium poly(acrylate) (PANa) on the hydration of calcium sulfate hemihydrate (CaSO412H2O) was investigated. This study reports the influence of sodium poly(acrylate) on hemihydrate dissolution, on homogenous and heterogeneous gypsum (CaSO42H2O) nucleation as well as on gypsum growth. It is shown that adsorption of PANa does not hinder the dissolution of hemihydrate in the present experimental conditions.

Jean-Philippe Boisvert; Marc Domenech; Alain Foissy; Jacques Persello; Jean-Claude Mutin

2000-01-01

10

Effects on aflatoxin M1 residues in milk by addition of hydrated sodium calcium aluminosilicate to aflatoxin-contaminated diets of dairy cows.  

PubMed

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for agricultural feeds, was added to aflatoxin (AF)-contaminated diets of 3 lactating dairy cows and evaluated for its potential to reduce aflatoxin M1 (AFM1) residues in milk. During phase I, cows were fed alternating diets that consisted of 200 micrograms of AF/kg of feed for 7 days, 0.5% HSCAS plus 200 micrograms of AF/kg of feed for 7 days, and feed with the HSCAS removed for a final 7 days. The AFM1 milk concentrations from the intervals with HSCAS added to diets were compared with those times when HSCAS was absent. The presence of 0.5% HSCAS in feed containing 200 micrograms of AF/kg reduced AFM1 secretion into the milk by an average of 0.44 micrograms/L (from pretreatment of 1.85 micrograms/L to 1.41 micrograms/L with HSCAS, a 24% reduction). Following a 10-day period of noncontaminated feed consumption and no AFM1 residues in the milk, phase II of the study was begun. The same experimental design as phase I was used, but the dosages of HSCAS and AF were changed to 1.0% and 100 micrograms/kg of feed, respectively. The addition of 1.0% HSCAS in feed containing 100 micrograms of AF/kg decreased AFM1 content in the milk by an average of 0.40 micrograms/L (from a pretreatment of 0.91 micrograms/L to 0.51 micrograms/L when HSCAS was present, a 44% reduction). These findings suggest that HSCAS, a high-affinity sorbent compound for AF in vitro, is capable of reducing the secretion of AFM1 into milk. PMID:1659263

Harvey, R B; Phillips, T D; Ellis, J A; Kubena, L F; Huff, W E; Petersen, H D

1991-09-01

11

In vitro and in vivo efficacy of a hydrated sodium calcium aluminosilicate to bind and reduce aflatoxin residues in tissues of broiler chicks fed aflatoxin B1.  

PubMed

The aim of this study was to determine the binding capacity of a hydrated sodium calcium aluminosilicate (HSCAS) for aflatoxin B(1) (AFB(1)), and the efficacy of the HSCAS to reduce the concentrations of residual AFB(1) and its metabolites in the liver and kidney of broilers fed AFB(1). One hundred 1-d-old male broilers (Ross 708) were maintained in chick batteries and allowed ad libitum access to feed and water. A completely randomized design was used with 5 replicate pens of 5 chicks assigned to each of 4 dietary treatments from hatch to 21 d. Dietary treatments included the following: A) basal diet (BD), with no HSCAS or AFB(1), B) BD supplemented with 0.5% HSCAS only, C) BD supplemented with 2.5 mg of AFB(1)/kg of feed, and D) BD supplemented with 2.5 mg of AFB(1)/kg of feed and 0.5% HSCAS. On d 21, 5 chicks from each treatment were anesthetized with carbon dioxide, killed by cervical dislocation, and samples of liver and kidney were collected for analysis of AFB(1) residues. The percentage of AFB(1) bound for each concentration of adsorbent (100, 10, 1, 0.5, 0.25, and 0.05 mg/10 mL) was 100, 91.1, 81.8, 75.4, 40.1, and 8.8%, respectively. Concentrations of aflatoxin residues (AFB(1), aflatoxicol, aflatoxins B(2) and G(1)) were lower (P < 0.05) in livers and kidneys of birds fed AFB(1) plus HSCAS (diet D), when compared with birds fed AFB(1) alone (diet C). However, histopathology data from the in vivo study indicated that HSCAS did not prevent lesions associated with aflatoxicosis. The decrease in the bioavailability of AFB(1) caused by the HSCAS reduced aflatoxin residues in liver and kidney, but not enough to completely prevent the toxic effects of AFB(1) in broilers. PMID:23243239

Neeff, D V; Ledoux, D R; Rottinghaus, G E; Bermudez, A J; Dakovic, A; Murarolli, R A; Oliveira, C A F

2013-01-01

12

Hydration of calcium sulfoaluminate cements - Experimental findings and thermodynamic modelling  

SciTech Connect

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.

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

13

Some Properties of the Calcium Aluminoferrite Hydrates.  

National Technical Information Service (NTIS)

Calcium aluminoferrite hydrates in two series, 4CaO.(Al2O3FeO3).nH2O (hexagonal plates) and 3CaO.(Al2O3Fe2O3).6H2O (isometric), were prepared from the anhydrous aluminoferrites by hydration in the presence of Ca(OH)2. The hexgonal phase was stable below 1...

E. T. Carlson

1966-01-01

14

Solubility and structure of calcium silicate hydrate  

Microsoft Academic Search

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

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

2004-01-01

15

Viscoelastic nature of calcium silicate hydrate  

Microsoft Academic Search

The origin of the time-dependent response of cement-based materials to applied stress has not been clearly resolved. The role of interlayer water in the mechanical behavior of calcium silicate hydrate (CSH) is still debated. In order to better understand the pertinent mechanisms, the stress relaxation tests were conducted on thin rectangular beams of compacted synthetic CSH powder and hydrated Portland

Rouhollah Alizadeh; James J. Beaudoin; Laila Raki

2010-01-01

16

Mechanical properties of calcium silicate hydrates  

Microsoft Academic Search

The dynamic mechanical properties of compacted samples of synthetic calcium silicate hydrate (CSH) were determined at variable\\u000a stoichiometries (C\\/S ratio). The stiffness and damping properties of the CSH systems were monitored at various increments\\u000a of mass loss from 11%RH following the removal of the adsorbed and interlayer water. The changes in the storage modulus (E?) and internal friction (tan ?)

Rouhollah Alizadeh; James J. Beaudoin; Laila Raki

2011-01-01

17

Electronic structure calculations of calcium silicate hydrates  

SciTech Connect

Many phases in the calcium-silicate-hydrate system can develop in cement exposed over long periods of time to temperatures above 25 C. As a consequence, chemical reactions involving these phases can affect the relative humidity and water chemistry of a radioactive waste repository that contains significant amounts of cement. In order to predict and simulate these chemical reactions, the authors are developing an internally consistent database of crystalline Ca-Si-hydrate structures. The results of first principles electronic structure calculations on two such phases, wollastonite (CaSiO{sub 3}) and xonotlite (Ca{sub 6}Si{sub 6}O{sub 17}(OH){sub 2}), are reported here. The calculated ground state properties are in very good agreement with experiment, providing equilibrium lattice parameters within about 1--1.4% of the experimentally reported values. The roles of the different types of oxygen atoms, which are fundamental to understanding the energetics of crystalline Ca-Si-hydrates are briefly discussed in terms of their electronic state densities. The good agreement with experiment for the lattice parameters and the consistency of the electronic density of states features for the two structures demonstrate the applicability of these electronic structure methods in calculating the fundamental properties of these phases.

Sterne, P.A. [Univ. of California, Davis, CA (United States). Dept. of Physics]|[Lawrence Livermore National Lab., CA (United States); Meike, A. [Lawrence Livermore National Lab., CA (United States)

1995-11-01

18

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

NASA Astrophysics Data System (ADS)

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 90C; 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 80C 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 80C. Monosulfate, ettringite, gypsum and a hydrogarnet phase (Ca3Al2O66H2O) 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 60C 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 80C 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 50C. 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.

Clark, Boyd Arthur

19

Hydroxyapatite formation from a hydrated calcium monohydrogen phosphate precursor  

Microsoft Academic Search

Hydrated calcium monohydrogen phosphate is proposed as the logical precursor in the formation of hydroxyapatite and a unifying theory for the formation of low calcium, or defect apatites, is presented. Structural relationships between calcium monohydrogen phosphate dihydrate and hydroxyapatite indicate that either material can provide the atomic arrangment for the epitaxial growth of one on the other. The formation of

Marion D. Francis; Ned C. Webb

1970-01-01

20

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

Code of Federal Regulations, 2013 CFR

...false 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...

2013-04-01

21

Characterization and numerical modeling of calcium silicate hydrate  

Microsoft Academic Search

The microstructure of cement-based materials determines most of their macroscale properties, such as strength, permeability, drying shrinkage, and creep. As new types of cementitious materials are developed, it becomes increasingly important to develop predictive models that connect the microstructure of concrete to its macroscale behavior. Calcium silicate hydrate (C--S--H), the primary hydration product of cement, is responsible for most of

Priscilla C. Fonseca

2009-01-01

22

Hydration of calcium sulfoaluminate cements Experimental findings and thermodynamic modelling  

Microsoft Academic Search

Calcium sulfoaluminate cements (CSA) are a promising low-CO2 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 1h and 28days at w\\/c ratios of 0.72 and 0.80, respectively.The main hydration product of

Frank Winnefeld; Barbara Lothenbach

2010-01-01

23

Nano-structured calcium silicate hydrate functionalised with iodine.  

PubMed

Nano-structured calcium silicate hydrate can physisorb or chemisorb iodine, making it interesting for medical or materials science applications, where a slow, controlled release of iodine is desired. It was found that iodine can be sorbed and released by applying the elemental halogen in solution, either as a gas or as a solid. At ambient temperatures the sorption and desorption process is quantitative and physical, meaning that the same amount of iodine is taken up and released. At temperatures above 32.5 degrees C (305.7K) iodine reacts with the calcium silicate hydrate forming a complex, which is stable above the sublimation temperature of iodine. The formation energy for the iodine calcium silicate hydrate complex was established to be 41.8+/-0.8kJmol(-1) by calorimetry and the nature of the complex was investigated using X-ray photoelectron spectroscopy. PMID:19682703

Borrmann, Thomas; Johnston, James H; McFarlane, Andrew J; Richardson, Michael J; O'Connor, Sean J

2009-08-13

24

Tricalcium aluminate hydration in the presence of calcium sulfite hemihydrate  

Microsoft Academic Search

This article reports on the study to evaluate the potential possibility of regulating the tricalcium aluminate (C3A) hydration process by the addition of calcium sulfite hemihydrate. The kind and the form of hydration products were studied in the system: C3ACaSO30.5H2OH2O and C3ACaSO30.5H2OCa(OH)2H2O by use of XRD, DTA and SEM\\/EDS methods as well as the kinetics of hydration along with chemical

A Lagosz; J Malolepszy

2003-01-01

25

Measurements of thermophysical properties of sodium acetate hydrate  

Microsoft Academic Search

Methods to measure the thermal conductivity, the specific heat capacity, and the heat of fusion of sodium acetate hydrate have been developed and the measured results have been reported for various concentrations and especially for various supercooling temperatures. Thermal conductivity was measured by using a probe method with a thermistor. The sensor element is very small, with a diameter of

N. Araki; M. Futamura; A. Makino; H. Shibata

1995-01-01

26

Sodium Removal from Hanford Waste Simulants Using Hydrated Antimony Pentoxide  

Microsoft Academic Search

Sodium has been removed from each of the three Hanford waste simulants with Hydrated Antimony Pentoxide (HAP) to facilitate technetium measurement by ICP-MS. Technetium was successfully measured in simulants A and B with small dilutions of the simulants (10x). Matrix interference, probably due to organic components, prevented the accurate measurement of Tc in simulant C. HAP has been used for

Tovo

1999-01-01

27

Calcium sulphate hemihydrate hydration leading to gypsum crystallization  

Microsoft Academic Search

The hydration of calcium sulphate hemihydrate (CaSO40.5H2O) leading to the crystallization of gypsum (calcium sulphate dihydrate CaSO42H2O) has been the subject of several investigationsover a long period and a vast amount of data is widely distributed throughout in the literature. In this review article an overall picture of the subject is presented. The properties of the two hemihydrates (?-

N. B. Singh; B. Middendorf

2007-01-01

28

Intrinsic elastic properties of Calcium Silicate Hydrates by nanoindentation  

Microsoft Academic Search

Calcium Silicate Hydrate (C-S-H) nanoparticles were partially recrystallized by Ostwald ripening after long-term equilibrium in calcium hydroxide solution of different concentration, leading to C-S-H of different Ca\\/Si ratio. The atomically smooth microdomains obtained have made possible the investigation of the intrinsic elastic properties of C-S-H in the direction perpendicular to the plane of the silicate layers. This has been carried

C. Plassard; E. Lesniewska; I. Pochard; A. Nonat

29

Modeling Nanomechanical Behavior of Calcium-Silicate-Hydrate.  

National Technical Information Service (NTIS)

The Discrete Element Method (DEM) was used to model the nanomechanical behavior of Calcium-Silicate-Hydrate (C-S-H). The interparticle forces consist of the traditional friction and contact forces that operate in granular materials, with the addition of n...

D. Pelessone J. F. Peters M. Q. Chandler

2012-01-01

30

Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.  

ERIC Educational Resources Information Center

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)

Henrickson, Charles H.; Robinson, Paul R.

1979-01-01

31

Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.  

ERIC Educational Resources Information Center

|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)|

Henrickson, Charles H.; Robinson, Paul R.

1979-01-01

32

Quantitative determination of calcium hydroxide in the presence of calcium silicate hydrates. Comparison between chemical extraction and thermal analysis  

Microsoft Academic Search

A correct determination of the amount of calcium hydroxide in the presence of calcium silicate hydrates has great importance in the field of cement chemistry. The evaluation of the composition of the calcium silicate hydrates formed during the hydration of C3S (the common cement chemistry notation is used herein: C=CaO, S=SiO2, H=H20), C2S and Portland cement, the estimation of the

Gian Lorenzo Valenti; Raffaele Cioffi

1985-01-01

33

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

Code of Federal Regulations, 2013 CFR

...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture...

2013-04-01

34

Effect of Application of Acidified Porous Hydrate Calcium Silicate and Porous Hydrated Calcium Silicate on the Growth of Rice Plants (Oryza sativa L.)  

Microsoft Academic Search

The effect of the application of acidified porous hydrate calcium silicate (APS) in nursery bed soil and porous hydrate calcium silicate (PS) in paddy fields on the growth of rice plants (Oryza sativa L. cv. Hitomebore) was examined in 2002 and 2003. The results revealed the following: 1) Shoot dry weight of rice seedlings increased by APS treatment in nursery

Hironori Heinai; Masahiko Saigusa; Kazuo Yoshida; Hitoshi Okazaki

2005-01-01

35

Pressure induced reactions amongst calcium aluminate hydrate phases  

Microsoft Academic Search

The compressibilities of two AFm phases (strtlingite and calcium hemicarboaluminate hydrate) and hydrogarnet were obtained up to 5GPa 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

Ju-hyuk Moon; Jae Eun Oh; Magdalena Balonis; Fredrik P. Glasser; Simon M. Clark; Paulo J. M. Monteiro

2011-01-01

36

Microstructure, Porosity, and Mechanical Property Relationships of Calcium-Silicate-Hydrate.  

National Technical Information Service (NTIS)

It is well known that characteristics of hydrated calcium aluminosilicate materials (macrodefect-free, silica-enriched cement) are directly related to the bulk composition of the starting materials which dictate the phases developing during the hydration ...

A. Das Gupta E. Breval M. W. Grutzeck S. Q. Hoyle

1988-01-01

37

Measurements of thermophysical properties of sodium acetate hydrate  

NASA Astrophysics Data System (ADS)

Methods to measure the thermal conductivity, the specific heat capacity, and the heat of fusion of sodium acetate hydrate have been developed and the measured results have been reported for various concentrations and especially for various supercooling temperatures. Thermal conductivity was measured by using a probe method with a thermistor. The sensor element is very small, with a diameter of 0.5 mm and a length of 1.5 mm. Data for both the ordinary liquid and the supercooled liquid are smoothly connected to each other.

Araki, N.; Futamura, M.; Makino, A.; Shibata, H.

1995-11-01

38

Measurements of thermophysical properties of sodium acetate hydrate  

SciTech Connect

Methods to measure the thermal conductivity, the specific heat capacity, and the heat of fusion of sodium acetate hydrate have been developed and the measured results have been reported for various concentrations and especially for various supercooling temperatures. Thermal conductivity was measured by using a probe method with a thermistor. The sensor element is very small, with a diameter of 0.5 mm and a length of 1.5mm. Data for both the ordinary liquid and the supercooled liquid are smoothly connected to each.

Araki, N.; Makino, A. [Shizuoka Univ. Hamamatsu (Japan); Futamura, M. [Toshiba Co., Yokohama (Japan)] [and others

1995-11-01

39

Compression behaviour of anhydrous and hydrate forms of sodium naproxen.  

PubMed

The aim of the present work was to investigate the technological properties and the compression behaviour of the anhydrous and hydrate solid forms of sodium naproxen. Among the hydrates, the following forms were studied: the monohydrate (MSN), obtained by dehydrating a dihydrated form (DSN) in each turn obtained by exposing the anhydrous form at 55% RH; a dihydrated form (CSN) obtained by crystallizing sodium naproxen from water, the tetrahydrated form (TSN) obtained by exposing the anhydrous form at 75% RH. The physico-chemical (crystalline form and water content), the micromeritic (crystal morphology and particle size) and the mechanical properties (Carr's index, apparent particle density, compression behaviour, elastic recovery and strength of compact) were evaluated. We made every effort to reduce differences in crystal habit, particle size and distribution, and amount of absorbed water among the samples, so that the only factors affecting their technological behaviour would be the degree of hydration and the crystalline structure. This study demonstrates a correlation between the compression behaviour and the water molecules present in the crystalline structures. The sites where water molecules are accommodated in the crystalline structure behave like weak points where the crystalline lattice yields under compression. The crystal deformability is proportional to the number of water molecules in these sites; the higher the water content, the higher the deformability, because the densification behaviour changes from a predominantly elastic deformation to a plastic behaviour. The deformability is responsible for a higher densification tendency that favours larger interparticle bonding areas that may explain the better tabletability of TSN and CSN. PMID:20117196

Malaj, Ledjan; Censi, Roberta; Gashi, Zehadin; Di Martino, Piera

2010-02-01

40

Late sodium current in the pathophysiology of cardiovascular disease: consequences of sodium-calcium overload  

PubMed Central

Late sodium current in cardiac cells is very small compared with the fast component, but as it flows throughout the action potential it may make a substantial contribution to sodium loading during each cardiac cycle. Late sodium current may contribute to triggering arrhythmia in two ways: by causing repolarisation failure (early afterdepolarisations); and by triggering late afterdepolarisations attributable to calcium oscillations in sodiumcalcium overload conditions. Reduction of late sodium current would therefore be expected to have therapeutic benefits, particularly in disease states such as ischaemia in which sodiumcalcium overload is a major feature.

Noble, D; Noble, P J

2006-01-01

41

Electronic structure of sodium cobalt oxide: Comparing mono- and bilayer hydrate  

Microsoft Academic Search

To shed light on the mechanism of superconductivity in sodium cobalt oxide bilayer-hydrate (BLH), we perform a density functional calculation with full structure optimization for BLH and its related nonsuperconducting phase, monolayer hydrate (MLH). We find that these hydrates have similar band structures, but a notable difference can be seen in the a1g band around the Fermi level. While its

Ryotaro Arita

2005-01-01

42

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

Code of Federal Regulations, 2013 CFR

... 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...

2013-04-01

43

75 FR 39025 - Determination That ACTONEL (Risendronate Sodium) Tablets, 75 Milligrams, and ACTONEL WITH CALCIUM...  

Federal Register 2010, 2011, 2012, 2013

...Tablets, 75 Milligrams, and ACTONEL WITH CALCIUM (Risendronate Sodium and Calcium Carbonate (Copackaged)) Tablets, 35 Milligrams...Tablets, 75 milligrams (mg), and ACTONEL WITH CALCIUM (risendronate sodium and calcium...

2010-07-07

44

Surface reactivity/stability and hydration of calcium silicate phases  

NASA Astrophysics Data System (ADS)

Recent studies on synthetic calcium silicate structures revealed important mechanisms to tune the reactivity of various cement phases. Interaction of water with dicalcium silicate (C2S-belite) and tricalcium silicate (C3S-alite), dominant phases in Portland Cement, are the most important and anticipated reactions. In this work, using first-principles calculations, a fundamental understanding of how water pressure affects the reactivity of C3S and C2S phases is provided. In order to understand the hydration of different phases, as a first step the surface energetics of all lower index orientations are calculated and the stability/reactivity of the surfaces are determined. Taking into account the most and least energetic surfaces of the C3S phase, detailed analyses are carried out in order to understand the induction period in hydration. Surface transformation from highly reactive C3S to low reactive C2S revealed that upon increasing the water pressure, the surface with C2S character becomes energetically more favorable. Reduction of the surface energy is more intense in the case of proton exchange of surface Ca atoms. Our calculations suggest that these processes are the most probable mechanisms underlying the rapid decrease in reactivity in alite hydration.

Durgun, Engin; Ataca, Can; Jennings, Hamlin M.; Grossman, Jeffrey C.

2013-03-01

45

Uptake of chloride and carbonate ions by calcium monosulfoaluminate hydrate  

SciTech Connect

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).

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

46

Hydration patterns and salting effects in sodium chloride solution  

NASA Astrophysics Data System (ADS)

The salting effects of 2M sodium chloride electrolyte are studied based on a series of model solutes with properties ranging from hydrophobic to hydrophilic. Generally, hydrophobic solutes will be salted out and hydrophilic solutes will be salted in by NaCl solution. The solvation free energy changes are highly correlated with Kirkwood-Buff integrals. The underlying mechanism resorts to the preferential binding of ions and water to solutes. Our results demonstrate that the salting effect not only depends on the salt's position in Hofmeister series, but also on the solutes' specifics. Taking the hydration free energies of solutes and ions as independent variables, a schematic diagram of salting effects is suggested. The resolved multifaceted salting effects rely on the sensitive balance of the tripartite interaction among solutes, ions, and water.

Li, Weifeng; Mu, Yuguang

2011-10-01

47

Influence of calcium ions on the crystallization of sodium bicarbonate  

Microsoft Academic Search

In industrial crystallization of sodium bicarbonate (sodium hydrogenocarbonate), the presence of calcium ions in solutions is unavoidable due to the production process. The understanding of the Ca2+ role in NaHCO3 crystallization would be helpful for improving the quality of the final products.The influence of calcium ions on NaHCO3 crystallization was investigated in a 5-l mixed suspension mixed product removal crystallizer

Y. Zhu; Paul Demilie; Perrine Davoine; Thierry Cartage; Marie-Paule Delplancke-Ogletree

2005-01-01

48

Rapid discharge performance of composite electrode of hydrated sodium manganese oxide and acetylene black  

Microsoft Academic Search

Hydrated sodium manganese oxide was synthesized by reducing permanganate ion using ethanol by a solgel method. By including acetylene black in the synthetic reaction, we obtained composite materials in which sodium manganese oxide hydrate particles were small and mixed well with the acetylene black. We evaluated those composites as a lithium battery cathode and found that they showed 170mAhg?1 under

Mitsuhiro Hibino; Hirokazu Kawaoka; Haoshen Zhou; Itaru Honma

2004-01-01

49

Process for making a calcium/sodium ferrate adduct by the electrochemical formation of sodium ferrate  

SciTech Connect

Described is a process for making a calcium/sodium ferrate adduct with sodium ferrate in a divided-type electrolysis cell. The anolyte chamber of the cell is charged with an aqueous solution of sodium hydroxide and a sodium ferrate-stabilizing proportion of at least one sodium halide salt. The anolyte chamber additionally contains ferric ions (Fe(III)). The catholyte chamber contains an aqueous sodium hydroxide solution during operation. The source of ferric ion in the anolyte may be either an iron-containing anode or at least one iron-containing compound present in the anolyte solution or both. The preferred material separating the anolyte chamber from the catholyte chamber is comprised of a gas- and hydraulic-impermeable, ionically-conductive, chemically-stable ionomeric film (e.g., a cation-exchange membrane with carboxylic, sulfonic or other inorganic exchange sites). Sodium ferrate is prepared in the anolyte chamber by passing an electric current and impressing a voltage between the anode and cathode of the cell. During electrolysis, sodium ferrate forms in the aqueous sodium hydroxide anolyte. This anolyte is reacted with a calcium compound to produce a calcium/sodium ferrate adduct. Alternatively the sodium ferrate may be first recovered in a solid form and then reacted with a calcium compound to produce said adduct.

Deininger, J.P.; Dotson, R.L.

1984-05-29

50

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

Microsoft Academic Search

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 m,45Ca efflux was largely dependent upon external Na and Ca. The Na0-dependent

M. P. Blaustein; J. M. Russell

1975-01-01

51

Possible states of chloride in the hydration of tricalcium silicate in the presence of calcium chloride  

Microsoft Academic Search

Calcium chloride may be present in the free, adsorbed or interlayer state in hydrating tricalcium silicate. Attempts have\\u000a been made to study these states to correlate some of the physical, chemical and mechanical properties.

V. S. Ramachandran

1971-01-01

52

Chloride binding to calcium silicate hydrates (CSH) in cement paste: a molecular dynamics analysis  

Microsoft Academic Search

A research study was recently conducted using the molecular dynamics approach to investigate the physico-chemical nature of interactions between chloride ions and various hydration products of cement that could lead to chloride accumulation in concrete. This paper presents the findings of one primary focus of the study, i.e. studying the transport behaviour of chloride ions in the calcium silicate hydrate

Tongyan Pan; Kaiming Xia; Linbing Wang

2010-01-01

53

Phase studies of pozzolanic stabilized calcium silicate hydrates at 180 C  

Microsoft Academic Search

Phase studies of calcium silicate hydrates formed at elevated temperature and pressure have been well documented. At 180 C, the initially formed amorphous calcium silicate gel [C-S-H] transforms into well-defined crystalline phases, the stability of which is primarily dependent on the C\\/S ratio in the CaO-SiO2-H2O system and the hydrothermal conditions. Hillebrandite [C2SH], ?-dicalcium silicate hydrate [?-C2SH] and ?-tricalcium silicate

K. Luke

2004-01-01

54

Sodium-calcium exchangers contribute to the regulation of cytosolic calcium levels in mouse taste cells  

PubMed Central

Taste cells use multiple signalling mechanisms to generate unique calcium responses to distinct taste stimuli. Some taste stimuli activate G-protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). We recently demonstrated that a constitutive calcium influx exists in taste cells that is regulated by mitochondrial calcium transport and that the magnitude of this calcium influx correlates with the signalling mechanisms used by the taste cells. In this study, we used calcium imaging to determine that sodiumcalcium exchangers (NCXs) also routinely contribute to the regulation of basal cytosolic calcium and that their relative role correlates with the signalling mechanisms used by the taste cells. RT-PCR analysis revealed that multiple NCXs and sodiumcalciumpotassium exchangers (NCKXs) are expressed in taste cells. Thus, a dynamic relationship exists between calcium leak channels and calcium regulatory mechanisms in taste cells that functions to keep cytosolic calcium levels in the appropriate range for cell function.

Laskowski, Agnieszka I; Medler, Kathryn F

2009-01-01

55

Regulation of the sodium permeability of the luminal border of toad bladder by intracellular sodium and calcium: role of sodium-calcium exchange in the basolateral membrane  

Microsoft Academic Search

Sodium movement across the luminal membrane of the toad bladder is the rate-limiting step for active transepitheliaI transport. Recent studies suggest that changes in intracellular sodium regulate the Na permeability of the luminal border, either directly or indirectly via increases in cell calcium induced by the high intracellular sodium. To test these proposals, we measured Na movement across the luminal

HERBERT S. CHASE; QAIS AL-AWQATI

1981-01-01

56

[Physical and chemical characteristics of a new cefazolin sodium hydrate crystal].  

PubMed

One kind of new cefazolin sodium hydrate crystal was obtained in the isopropyl alcohol - water system. There are two symmetry independent molecules in the asymmetric unit, both being well ordered in the lattice, and ten independent water positions but generally four to six (mean five) water molecules and one sodium ion present in the unit cell structure. Huge solvent tunnels can be found. Again there are two general regions of water molecules, those in the large solvent tunnels and those in proximity of the sodium ion and the tetrazole moieties of the drug molecule. The physical and chemical characteristics of the new cefazolin sodium hydrate crystal are similar to that of the alpha-form cefazolin sodium crystal, and the new crystal has better chemical stability than amorphous cefazolin sodium powder. PMID:18956782

Hu, Chang-Qin; Yin, Li-Hui; Liang, Ya-Ning

2008-08-01

57

Sensory and Associated Reactions to Mineral Dusts: Sodium Borate, Calcium Oxide, and Calcium Sulfate  

Microsoft Academic Search

Occupational exposure limits (OELs) for irritant dusts have had no quantifiable bases. This study (1) charted chemosensory feel, denoted chemesthesis here, to dusts of calcium oxide (1 to 5 mg\\/m), sodium tetraborate pentahydrate [sodium borate] (5 to 40 mg\\/m), and calcium sulfate (10 to 40 mg\\/m); (2) examined correlates of the chemesthetic sensations; and (3) sought to illuminate the basis

William S. Cain; Alfredo A. Jalowayski; Michael Kleinman; Nam-Soo Lee; Bo-Ryung Lee; Byung-Hoon Ahn; Kevin Magruder; Roland Schmidt; Brian K. Hillen; Craig B. Warren; B. Dwight Culver

2004-01-01

58

Sodium Current-Induced Release of Calcium from Cardiac Sarcoplasmic Reticulum  

Microsoft Academic Search

The role of sodium-calcium exchange at the sarcolemma in the release of calcium from cardiac sarcoplasmic reticulum was investigated in voltage-clamped, isolated cardiac myocytes. In the absence of calcium entry through voltage-dependent calcium channels, membrane depolarization elicited release of calcium from ryanodine-sensitive internal stores. This process was dependent on sodium entry through tetrodotoxin-sensitive sodium channels. Calcium release under these conditions

Normand Leblanc; Joseph R. Hume

1990-01-01

59

Determination of Nitrogen, Sulphur, Phosphorus, Potassium, Sodium, Calcium, and Magnesium in Plant Material by Automatic Analysis.  

National Technical Information Service (NTIS)

Methods are proposed for the rapid determination of nitrogen, sulphur, phosphorus, potassium, sodium, calcium, and magnesium in plant material by automated chemical analysis. Phosphorus, potassium, calcium, magnesium, and sodium are determined in nitric-p...

C. H. Williams J. R. Twine

1967-01-01

60

Characterization of ion distributions near the surface of sodium-containing and sodium-depleted calcium aluminosilicate glass melts  

Microsoft Academic Search

The distribution of cation and anion components of sodium containing calcium aluminosilicate glass was studied by classical molecular dynamics simulations in a high temperature melt in the bulk and at the vacuum-melt interface. A significant redistribution of the sodium and non-bridging oxygen ions was observed. Subsequently, a sodium depleted calcium aluminosilicate glass melt was simulated to determine the sensitivity of

Louis R. Corrales; Jincheng Du

2006-01-01

61

Carbon dioxide absorption mechanisms of sodium added to calcium oxide at high temperatures  

Microsoft Academic Search

To apply the CO2 absorber at about 1000C for integrated coal gasification combined cycle (IGCC) furnace, the reactions of calcium oxide and CO2 at high temperatures was examined. Calcium carbonate reacts with sodium hydrogen carbonate below 200C and forms sodiumcalcium complex carbonate. The sodiumcalcium complex carbonate melts at 813C, and the carbon dioxide absorption and discharge reversible reactions of calcium-oxide

Shunkichi Ueno; D. Doni Jayaseelan; Jihong She; Naoki Kondo; Tatsuki Ohji; Shuzo Kanzaki

2004-01-01

62

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

Microsoft Academic Search

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

Xiandong Cong; R. James Kirkpatrick

1996-01-01

63

Kinetics of tricalcium aluminate and tetracalcium aluminoferrite hydration in the presence of calcium sulfate  

SciTech Connect

Hydration reactions of C[sub 3]A with C[sub 4]AF with calcium sulfate hemihydrate and gypsum were investigated and the kinetics of the reactions compared. The rates of C[sub 3]A and C[sub 4]AF hydration, as determined by heat evolution, vary depending on whether the sulfate-containing reactant is gypsum or calcium sulfate hemihydrate. The following sequence of reactions involving C[sub 4]AF occurs when hemihydrate is the reactant: gypsum formation during the first hour, ettringite formation between 20 and 36 hours, and the conversion of ettringite to monosulfate over a period of about 12 hours. Monosulfate formation initiates prior to the complete consumption of gypsum. The onset of this conversion occurs at a shorter hydration time when hemihydrate is a reactant and the total amount of heat evolved is lower. The hydration reactions in saturated calcium hydroxide solution occur more slowly than those in water. Based on heat liberation, C[sub 4]AF reacts at a much higher rate than C[sub 3]A. Ettringite formation occurs during the first 8 to 9 days of C[sub 3]A hydration. Once the gypsum is consumed, ettringite converts to monosulfate during two additional days. Compared to gypsum, hemihydrate decreases the rates of hydration of both C[sub 3]A and C[sub 4]AF. The effects on the hydration characteristics of C[sub 4]AF are significant. The hydration of C[sub 3]A with gypsum in water, in saturated Ca(OH)[sub 2] solution, and in 0.3M NaOH solution were compared. Heat evolution is the lowest for hydration in 0.3M NaOH. The onset of monosulfate formation occurs prior to the complete reaction between gypsum and C[sub 3]A in the NaOH solution.

Brown, P.W. (Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering)

1993-12-01

64

Fluoride in Dog Parotid Saliva After Intravenous Administration of Sodium Fluoride, Sodium Monofluorophosphate, and Calcium Fluoride  

Microsoft Academic Search

Sodium fluoride, sodium monofluorophosphate, or calcium fluoride, in amounts equivalent to 0.5 mg\\/kg, were given intravenously to dogs and the effect on parotid saliva F was determined. Significant (P < 0.01) differences in saliva F levels were related to the ionization of NaF, the hydrolysis of the PO3F ion, and the insolubility of CaF2.

Ralph P. Feller; Ira L. Shannon

1975-01-01

65

Structural models of random packing of spheres extended to bricks: simulation of the nanoporous calcium silicate hydrates  

Microsoft Academic Search

Structure simulation algorithms of random packing of spheres and bricks have been developed. These algorithms were used to reproduce the nanostructure of the cementitious calcium silicate hydrates. The textural parameters (specific surface area, porosity, pore size, etc.) of a calcium silicate hydrates (C-S-H) sample, the main binding phase of hydrated cements, have been derived from N2-physisorption experiments. At the same

Victor Morales-Flrez; Fabrice Brunet

2009-01-01

66

Stimulation of calcium-sodium exchange in dog red blood cells by hemolysis and resealing.  

PubMed

Osmotic hemolysis and resealing greatly increase calcium influx in dog red blood cells. The resealed ghosts show a saturable calcium entry pathway with complex kinetics. As expected for a calcium-sodium exchanger, calcium uptake is stimulated by internal sodium and inhibited by external sodium. Compared to fresh, intact red cells the resealed ghost calcium-sodium exchanger is less responsive to quinidine and to alterations in medium tonicity. The differences in calcium uptake rate among cells from different donors are minimized in the ghost preparation. There are several ways to stimulate sodium-dependent calcium movements in these cells, of which hemolysis-resealing is the most potent. The results of these and previous studies suggest that dog red blood cells have a latent capacity for calcium-sodium exchange. PMID:3415988

Parker, J C

1988-09-01

67

Accelerated growth of calcium silicate hydrates: Experiments and simulations  

SciTech Connect

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.

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

2011-12-15

68

Aqueous solutions of calcium ions: hydration numbers and the effect of temperature.  

PubMed

Hydration numbers of calcium ions are determined from extensive measurements of colligative properties of water solutions of calcium salts. The hydration numbers reported refer to the average number of water molecules that are bound sufficiently strongly to calcium ions so as to be removed from the solvent and become part of the solute. Contrary to common descriptions of deviations from ideal behavior for concentrated solutions, ideal behavior is demonstrated when mole fractions are calculated by taking account of such bound water. Measurements over wide concentration and temperature ranges are used to obtain the effect of temperature on the average hydration number of Ca(2+). Freezing point depression measurements yield a hydration number of 12.0 +/- 0.8. Boiling point elevations yield 6.7 +/- 0.6. Consistent with this, vapor pressure measurements from 0 to 200 degrees C show a gradual decrease in hydration number with increasing temperature, with a value of 5.0 at 200 degrees C. PMID:16853671

Zavitsas, Andreas A

2005-11-01

69

Hydration of calcium oxide surface predicted by reactive force field molecular dynamics.  

PubMed

In this work, we present the parametrization of Ca-O/H interactions within the reactive force field ReaxFF, and its application to study the hydration of calcium oxide surface. The force field has been fitted using density functional theory calculations on gas phase calcium-water clusters, calcium oxide bulk and surface properties, calcium hydroxide, bcc and fcc Ca, and proton transfer reactions in the presence of calcium. Then, the reactive force field has been used to study the hydration of the calcium oxide {001} surface with different water contents. Calcium oxide is used as a catalyzer in many applications such as CO(2) sequestration and biodiesel production, and the degree of surface hydroxylation is a key factor in its catalytic performance. The results show that the water dissociates very fast on CaO {001} bare surfaces without any defect or vacancy. The surface structure is maintained up to a certain amount of water, after which the surface undergoes a structural rearrangement, becoming a disordered calcium hydroxyl layer. This transformation is the most probable reason for the CaO catalytic activity decrease. PMID:22316164

Manzano, Hegoi; Pellenq, Roland J M; Ulm, Franz-Josef; Buehler, Markus J; van Duin, Adri C T

2012-02-22

70

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

Microsoft Academic Search

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

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

2005-01-01

71

Surfactant-assisted sonochemical synthesis of hollow calcium silicate hydrate (CSH) microspheres for drug delivery  

Microsoft Academic Search

Hollow calcium silicate hydrate (CSH) microspheres with diameters around 1?m were synthesized by a surfactant-assisted sonochemical route, and the products were characterized by XRD, SEM, FETEM and BET techniques. The results suggested that the ultrasound radiation, surfactant and Ca source were important factors which affected the formation of hollow microspheres. Based on the observation of products in different reaction systems,

Meili Zhang; Jiang Chang

2010-01-01

72

Effect of Na and Al on the phase composition and morphology of autoclaved calcium silicate hydrates ? ? This paper was originally submitted to Advanced Cement Based Materials. The paper was received at the Editorial Office of Cement and Concrete Research on 5 November 1998 and accepted in final form on 16 July 1999  

Microsoft Academic Search

The hydrated materials were synthesized at 160240C in hydrothermal conditions. The series of samples with differing CaO\\/SiO2 ratios and doped with NaOH and Al(OH)3 (used as Na- and Al-bearing compounds) were produced, yielding materials consisting of the ill-crystallized calcium silicate hydrates and\\/or more crystalline calcium silicate phases. Generally, in the presence of sodium ions the acceleration of reactions leads to

Wieslawa Nocu-Wczelik

1999-01-01

73

Hydration patterns and salting effects in sodium chloride solution  

Microsoft Academic Search

The salting effects of 2M sodium chloride electrolyte are studied based on a series of model solutes with properties ranging from hydrophobic to hydrophilic. Generally, hydrophobic solutes will be salted out and hydrophilic solutes will be salted in by NaCl solution. The solvation free energy changes are highly correlated with Kirkwood-Buff integrals. The underlying mechanism resorts to the preferential binding

Weifeng Li; Yuguang Mu

2011-01-01

74

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

Microsoft Academic Search

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

Jacob Lemann; Richard W Gray; Joan A Pleuss

1989-01-01

75

Reaction of sodium calcium borate glasses to form hydroxyapatite.  

PubMed

This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO . 2Na(2)O . 6B(2)O(3) or 2CaO . 2Na(2)O . 6B(2)O(3) glass and a 0.25 M phosphate (K(2)HPO(4)) solution at 37, 75 and 200 degrees C. Glass samples in the form of irregular particles (125-180 microm) and microspheres (45-90 and 125-180 microm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K(2)CO(3)) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO . 2Na(2)O . 6B(2)O(3)), or reacted at an elevated temperature (75 degrees C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 degrees C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape. PMID:17486301

Han, Xue; Day, Delbert E

2007-05-08

76

Synaptosomal calcium influx is activated by sodium fluoride  

SciTech Connect

Neuronal calcium channels can be modulated by changes in membrane potential or by activation of channel-associated receptors. The latter may be modulated by guanine nucleotide binding proteins. NaF, which activates guanine nucleotide binding proteins, caused a large stimulation of /sup 45/Ca/sup 2 +/ uptake by synaptosomes prepared from rat brain. Stimulation of /sup 45/Ca/sup 2 +/ influx by NaF (i) was apparent in media containing either 5 mM-K+ or 50 mM-K+, (ii) was slower than the fast-phase of voltage-dependent /sup 45/Ca/sup 2 +/ influx but continued for a longer period of time than did depolarization-induced /sup 45/Ca/sup 2 +/ influx, and (iii) was not mimicked or modified by a number of drugs, including ouabain, dinitrophenol, sodium azide or sodium vanadate. These results are consistent with the hypothesis that NaF activates a guanine nucleotide binding protein associated with receptor-coupled calcium channels, resulting in stimulation of calcium influx.

Jope, R.S.; Lally, K.M.

1988-03-15

77

Characterization of ion distributions near the surface of sodium-containing and sodium-depleted calcium aluminosilicate glass melts  

SciTech Connect

The distribution of cation and anion components of sodium containing calcium aluminosilicate glass was studied by classical molecular dynamics simulations in a high temperature melt in the bulk and at the vacuum-melt interface. A significant redistribution of the sodium and non-bridging oxygen ions was observed. Subsequently, a sodium depleted calcium aluminosilicate glass melt was simulated to determine the sensitivity of the redistribution of ions near the vacuum-melt interface to the presence of sodium ions. It is found that the thermodynamic equilibrium condition near a surface favors the enrichment of non-bridging oxygen ions that is closely associated with enrichment of the sodium ions.

Corrales, Louis R.; Du, Jincheng

2006-01-01

78

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

SciTech Connect

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.

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

1998-06-01

79

The effect of dietary sodium on urinary calcium and potassium excretion in normotensive men with different calcium intakes  

Microsoft Academic Search

On the basis oftheir usual calcium intake, 12 healthy normotensive male students were divided into a low and a high calcium group. Both groups were provided with complete diets containing the same calculated quantities, expressed per Mi, of protein, fat, carbohydrate, sodium, potassium, phosphorus, and calcium. After an initial period of two weeks during which all #{149} participants received an

J. M. Castenmiller; R. P. Mensink; Heijden van der L; T. Kouwenhoven; J. G. A. J. Hautvast; Leeuw de P. W; G. Schaafsma

1985-01-01

80

Neutrophil elastase inhibitor, sivelestat sodium hydrate prevents ischemiareperfusion injury in the rat bladder  

Microsoft Academic Search

In the present study, we evaluated the effect of neutrophil elastase inhibitor, sivelestat sodium hydrate on ischemiareperfusion\\u000a injury in the rat bladder. Rat abdominal aorta was clamping with a small clip to induce ischemiareperfusion injury in the\\u000a bladder. Eight-week-old male Sprague Dawley rats were divided into four groups; sham-operated control rats, 30min ischemia60min\\u000a reperfusion (IR) rats, and IR rats treated

Tomoharu Kono; Shin-ichi Okada; Motoaki Saito

2008-01-01

81

Nonlinear optical activity of anhydrous and hydrated sodium p-nitrophenolate  

Microsoft Academic Search

Differently hydrated sodium p-nitrophenolate (NPNa) crystals were obtained while growing them from different solvents such as methanol and water. Thermal analysis and powder X-ray diffraction studies were carried out on these crystals. Kurtz powder SHG technique was used for qualitative assessment of their nonlinear optical (NLO) activity. From the detailed single-crystal X-ray diffraction studies it is established that NPNa has

S. Brahadeeswaran; V Venkataramanan; H. L Bhat

1999-01-01

82

Crystal chemistry and structure refinement of five hydrated calcium borates  

USGS Publications Warehouse

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.

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

1964-01-01

83

Microstructure and Thermal Conductivity of Hydrated Calcium Silicate Board Materials  

Microsoft Academic Search

The thermal conductivity of a porous material is controlled by the thermal conductivities of its components and their spatial arrangement within the composite structure, e.g., the material's microstructure. In this study, the relationships between thermal conductivity and microstructural parameters, such as porosity and pore size are examined for two calcium silicate boards of different densities. Thermal conductivities are measured from

Dale P. Bentz; Paul E. Stutzman

2007-01-01

84

Transient reversal of the sodium/calcium exchanger boosts presynaptic calcium and synaptic transmission at a cerebellar synapse.  

PubMed

The sodium/calcium exchanger (NCX) is a widespread transporter that exchanges sodium and calcium ions across excitable membranes. Normally, NCX mainly operates in its "forward" mode, harnessing the electrochemical gradient of sodium ions to expel calcium. During membrane depolarization or elevated internal sodium levels, NCX can instead switch the direction of net flux to expel sodium and allow calcium entry. Such "reverse"-mode NCX operation is frequently implicated during pathological or artificially extended periods of depolarization, not during normal activity. We have used fast calcium imaging, mathematical simulation, and whole cell electrophysiology to study the role of NCX at the parallel fiber-to-Purkinje neuron synapse in the mouse cerebellum. We show that nontraditional, reverse-mode NCX activity boosts the amplitude and duration of parallel fiber calcium transients during short bursts of high-frequency action potentials typical of their behavior in vivo. Simulations, supported by experimental manipulations, showed that accumulation of intracellular sodium drove NCX into reverse mode. This mechanism fueled additional calcium influx into the parallel fibers that promoted synaptic transmission to Purkinje neurons for up to 400 ms after the burst. Thus we provide the first functional demonstration of transient and fast NCX-mediated calcium entry at a major central synapse. This unexpected contribution from reverse-mode NCX appears critical for shaping presynaptic calcium dynamics and transiently boosting synaptic transmission, and is likely to optimize the accuracy of cerebellar information transfer. PMID:23255722

Roome, Chris J; Power, Emmet M; Empson, Ruth M

2012-12-19

85

Sodium and calcium components of action potentials in Aplysia giant neurone  

PubMed Central

1. Action potentials resulting from direct stimulation can be recorded from the soma of the Aplysia giant neurone (located in the visceral ganglion) in sodium-free and in calcium-free external solutions. The neurones were impaled by internal micro-electrodes throughout the change of external solutions. 2. Complete replacement of either sodium or calcium in the bathing medium with Tris results in only a partial reduction of spike overshoot. Simultaneous replacement of both sodium and calcium reversibly and quickly abolishes the spike. 3. The sodium component of the spike in a calcium-free medium is blocked by tetrodotoxin; the drug has no effect on the calcium-dependent spike in sodium-free medium. Externally applied cobalt chloride blocks only the calcium-dependent component. 4. In calcium-free media, the overshoot value varies with sodium concentration in the manner predicted for a sodium electrode. In sodium-free media, the membrane behaves like a calcium electrode. 5. These results suggest that, during the normal action potential, both sodium and calcium act as carriers of the inward-directed current.

Geduldig, D.; Junge, D.

1968-01-01

86

Properties of calcium phosphate powder synthesized from calcium acetate and sodium hydrophosphate  

Microsoft Academic Search

The properties of powder synthesized from calcium acetate and sodium hydrophosphate with the ratio $$ \\\\left[ {{\\\\text{C}}{{\\\\text{a}}^{{2 + }}}} \\\\right]\\/\\\\left[ {{\\\\text{PO}}_4^{3 - }} \\\\right] $$ of the starting reagents equal to 1 have been investigated. After synthesis brushite, monetite, and octacalcium phosphate\\u000a were found in the powder. A substantial mass loss, equal to 26%, on heating is due to not

T. V. Safronova; V. I. Putlyaev; A. V. Kuznetsov; N. A. Ketov; A. G. Veresov

2011-01-01

87

Fasting urine excretion of magnesium, calcium, and sodium in patients with renal calcium stones  

Microsoft Academic Search

1.Urine excretion of magnesium (Mg), calcium (Ca) and sodium (Na) was studied in patients with renal Ca stones having normal kidney function (n=60), and in matched controls (n=60), on a free diet following an overnight fasting period. In stone formers, Mg was lower than in normals, whereas Ca was unusually high resulting in a significantly higher molar Ca\\/Mg ratio (p<0.001).2.In

P. O. Schwille; I. Schlenk; N. M. Samberger; C. Bornhof

1976-01-01

88

The control by internal calcium of membrane permeability to sodium and potassium  

PubMed Central

1. A study has been made of the relationship between the concentration of internal calcium and the permeability of human red cell membranes to sodium and potassium. 2. Fresh red cells contain very little calcium, but after being depleted of ATP by ageing they took up calcium from Ringer solution. The entry was unaffected by external sodium and potassium but was markedly pH dependent. When supplied with energy, calcium-loaded cells actively extruded calcium by a saturable process which was also unaffected by the distribution of sodium and potassium across the membranes. The activity of the calcium pump was sufficient to maintain the low internal concentration found under physiological conditions. 3. Raising internal calcium in metabolically poor cells caused a loss of cell potassium which was greater than the concomitant sodium gain. These changes were reversed when ATP was supplied. External calcium had no effect. The increase in permeability to sodium and potassium was enhanced by the simultaneous addition of fluoride, and, even more so, of iodoacetate. These inhibitors had no effect on membrane permeability unless calcium was also present. Inosine potentiated the action of fluoride and iodoacetate in causing potassium loss, by allowing more calcium to enter the cells. 4. The results suggest that the permeability of human red cell membranes to sodium and potassium is regulated by internal calcium, which in turn is controlled by a calcium pump that utilizes ATP.

Romero, P. J.; Whittam, R.

1971-01-01

89

The mechanical properties and hydration characteristics of cement pastes containing added-calcium coal gangue  

Microsoft Academic Search

The mechanical properties of several kinds of coal gangue calcined with limestone were Researched so as to find the optimum\\u000a way of calcinations with limestone. Microstructure and property of hydration process of cement pastes containing added-calcium\\u000a coal gangue were analyzed by means of scanning electron microscope (SEM) and method of mercury in trusion poremeasurement\\u000a (MIP), etc. The experiment can approve

Dongxu Li; Xuyan Song

2008-01-01

90

Morphological forms of tobermorite in hydrothermally treated calcium silicate hydrate gels  

SciTech Connect

The morphology of the calcium silicate hydrate phase, tobermorite, generally thought to be the bonding phase in ordinary portland cement, was studied. Tobermorite was hydrothermally synthesized at pH 12.6 at 150 C. The powder was characterized by XRD and SEM analysis. Modeling of the morphology was performed using the SHAPE and ATOMS programs. Two morphologies were produced: fibers and platelets. Computer calculations of equilibrium particle shape suggest that growth occurs on the (110)-type planes for both morphologies.

Bell, N.S.; Venigalla, S. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Gill, P.M. [Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.; Adair, J.H. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering]|[Pennsylvania State Univ., University Park, PA (United States). Materials Research Lab.

1996-08-01

91

Amelioration of Cadmium Polluted Paddy Soils by Porous Hydrated Calcium Silicate  

Microsoft Academic Search

Porous hydrated calcium silicate (PS) is a by-product of autoclave light weight concrete and is being used as a silicon fertilizer\\u000a in Japan. The impacts of this amendment on the yield and cadmium content of rice (Orzya sativa L. var. Kokoromachi), soil pH and the extractability of soil cadmium assessed by 1M NH4OAc were compared with those of silica gel

Xiu-Lan Zhao; Saigusa Masaihiko

2007-01-01

92

EXAFS study of U(VI) uptake by calcium silicate hydrates  

Microsoft Academic Search

Among the different cement minerals, calcium silicate hydrates (C-S-H) are the prime candidates for heavy metal binding because of their abundance and appropriate structure. Immobilization processes of heavy metals by cementitious materials, and in particular C-S-H phases, thus play an important role in multibarrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. In this study, the

M. Harfouche; E. Wieland; R. Dhn; T. Fujita; D. Kunz; M. Tsukamoto

2006-01-01

93

Effect of poly(diallyldimethylammonium chloride) on nanostructure and mechanical properties of calcium silicate hydrate  

Microsoft Academic Search

Studying the performance and behavior of calcium silicate hydrate (C-S-H)\\/polymer nanocomposites can be the first step for developing Portland cement-based materials with differentiated properties. Among the polymers available, poly(diallyldimethylammonium chloride)PDC is indicated by the literature as one of the most viable for producing C-S-H\\/polymer complexes. However, no consensus exists regarding the kind of interaction. In this work, low Ca\\/Si C-S-H

F. Pelisser; P. J. P. Gleize; A. Mikowski

2010-01-01

94

Sr 2+ Sorption and leach rate studies on synthetic calcium silicate hydroxy hydrate  

Microsoft Academic Search

Synthetic calcium silicate hydroxy hydrate, which is identical to unsubstituted and substituted 1.1-nm tobermorite mineral, has the capacity to pickup selectivity Sr2+ cation from mixed cationic solutions in the presence of 1,000 times concentrations of Na+, K+, Ca2+, Mg2+, and Ba2+. The selective uptake of Sr2+ from mixed cationic solutions and simulated intermediate level waste (ILW) solutions has been quantified

O. P. Shrivastava; T. Verma

1995-01-01

95

EXAFS study of Nd(III) uptake by amorphous calcium silicate hydrates (CSH)  

Microsoft Academic Search

Calcium silicate hydrate (CSH) phases control the immobilization of many metal cations in cementitious materials. In this study Nd binding to amorphous CSH phases with different Ca\\/Si (C\\/S) mol ratios (0.56, 0.87 and 1.54) and Nd loadings (7 and 35?mol\\/g), and which had been aged up to 270 days, has been investigated using extended X-ray absorption fine structure (EXAFS) spectroscopy.

P. Mandaliev; R. Dhn; B. Wehrli; E. Wieland

2010-01-01

96

A new model for the formation of calcium silicate hydrate (CSH)  

Microsoft Academic Search

2S) and tricalcium silicate (C3S) pastes are generally based on the notion that the dimeric calcium silicate hydrate (C-S-H) that begins to form at the end\\u000a of the induction period is not a stable phase. It is implied that its formation simply marks the beginning of a rather lengthy\\u000a equilibration process. This statement is based on the fact that the

M. W. Grutzeck

1999-01-01

97

Electrochemical characteristics of uranium ions in calcium chloride hydrate melts  

Microsoft Academic Search

Redox reactions of tetravalent uranium ion in calcium chloride hexahydrate CaCl26H2O melt ([CaCl2] = 6.9 M) were studied electrochemically and spectrophotometrically. Cyclic voltammograms in CaCl26H2O melt containing UCl4 were measured with a pyro-graphite carbon working electrode. A cathodic peak corresponding to the reduction of U4+ to U3+ was observed, and it was found to be controlled by the diffusion of

A. Uehara; T. Fujii; T. Nagai; O. Shirai; N. Sato; H. Yamana

2010-01-01

98

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

USGS Publications Warehouse

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.

Erd, R. C.; Ohashi, Y.

1984-01-01

99

Contrasting interactions of sodium and potassium with H 2 O in haplogranitic liquids and glasses at 200MPa from hydrationdiffusion experiments  

Microsoft Academic Search

This study examines hydrationdiffusion in the metaluminous haplogranite system at 200MPa H2O and 800300C. At 800C hydration is accompanied by melting and uphill diffusion of sodium from anhydrous glass toward the region of hydration and melting, whereas potassium diffuses away from the hydration front and into anhydrous glass. Silicon and aluminum are simply diluted upon hydration. There is no change

Antonio Acosta-Vigil; David London; George B. Morgan VI

2005-01-01

100

Solid-state characterization and dissolution properties of Fluvastatin sodium salt hydrates.  

PubMed

The present study reports the solid-state properties of Fluvastatin sodium salt crystallized from different solvents for comparison with crystalline forms of the commercially available raw material and United States Pharmacopeia (USP) reference standard. Fluvastatin (FLV) samples were characterized by several techniques; such as X-ray powder diffractometry, differential scanning calorimetry, thermogravimetry, liquid and solid-state nuclear magnetic resonance spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy, and scanning electron microscopy. In addition, intrinsic dissolution rate (IDR) of samples was performed in order to study the influence of crystalline form and other factors on rate and extent of dissolution. Three different forms were found. The commercial raw material and Fluvastatin-Acetonitrile (ACN) were identified as "form I" hydrate, the USP reference standard as "form II" hydrate and an ethanol solvate which presented a mixture of phases. Form I, with water content of 4%, was identified as monohydrate. PMID:23033850

Borgmann, Silvia H M; Bernardi, Larissa S; Rauber, Gabriela S; Oliveira, Paulo R; Campos, Carlos E M; Monti, Gustavo; Cuffini, Silvia L; Cardoso, Simone G

2012-10-04

101

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

Microsoft Academic Search

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

Roger A L Sutton; Norman L M Wong; John H Dirks

1979-01-01

102

Efficacy of calcium sodium phosphosilicate in managing dentinal hypersensitivity.  

PubMed

A large number of home use products have been tested and used for managing dentinal hypersensitivity. This eight-week clinical trial compared the temporal efficacy of a commercially available toothpaste containing calcium sodium phosphosilicate to that of a toothpaste containing potassium nitrate. For this study, 20 subjects (age 18 - 65) were screened using a visual analog scale (VAS) for sensitivity to a cold stimulus. Baseline VAS sensitivity scores to tactile stimulus were recorded for a minimum of two teeth per patient. Dentifrices were prescribed for all patients and sensitivity scores were re-evaluated at two, four, and eight weeks. Though both groups showed significant reductions in sensitivity scores, only at eight weeks was there a marginally significant difference (p = 0.0551) in sensitivity scores between the test group and the positive control group. PMID:23032238

Surve, Sai M; Acharya, Anirudh B; Shetty, Ananya; Thakur, Srinath L

103

The influence of sulphite on the methane fermentation of sodium and calcium acetates  

Microsoft Academic Search

Summary It has been proved that methane fermentation of sodium and calcium acetates is strongly inhibited by both sodium and calcium sulphites. In the region of optimum pH of this fermentation (pH 6.0 to 6.5) a concentration of 0.003 to 0.01 % sodium sulphite is enough to produce perceptible inhibition. At a concentration of 0.1 % Na2SO3 methane fermentation was

M. A. NOORDAM-GOEDEWAfiEN; A. Manten; F. M. Muller

1949-01-01

104

Crystallographic basis for calcium regulation of sodium channels  

PubMed Central

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 crystal structure of Ca2+-bound calmodulin (Ca2+/CaM) in complex with the inactivation gate (DIII-IV linker) of the cardiac sodium channel (NaV1.5). 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 Ca2+/CaM binding, which, in turn, sensitize or abolish Ca2+ regulation of full-length channels in electrophysiological experiments. Additional biochemical experiments support a model whereby a single Ca2+/CaM bridges the C-terminal IQ motif to the DIII-IV linker via individual N and C lobes, respectively. The data suggest that Ca2+/CaM destabilizes binding of the inactivation gate to its receptor, thus biasing inactivation toward more depolarized potentials.

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

2012-01-01

105

Equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride  

SciTech Connect

Natural gas components such as hydrogen sulfide, carbon dioxide, and ethane form gas hydrates of structure I under suitable temperature and pressure conditions. Information on such conditions is vital to the oil and gas industry in order to design and operate processing equipment and pipelines so that hydrate formation is avoided. Incipient equilibrium hydrate formation conditions for hydrogen sulfide, carbon dioxide, and ethane in aqueous solutions of ethylene glycol and sodium chloride were experimentally obtained in the temperature range 264--290 K and the pressure range 0.23--3.18 MPa. A variable-volume sapphire cell was used for the measurements.

Majumdar, A.; Mahmoodaghdam, E.; Bishnoi, P.R.

2000-02-01

106

Synthesis and single crystal structure refinement of the one-layer hydrate of sodium brittle mica  

NASA Astrophysics Data System (ADS)

A sodium brittle mica with the ideal composition [Na4]inter[Mg6]oct[Si4Al4]tetO20F4 was synthesized via melt synthesis in a gas tight crucible. This mica is unusual inasmuch as the known mica structure holds only room for two interlayer cations per unit cell and inasmuch as it readily hydrates despite the high layer charge while ordinary micas and brittle micas are non-swelling. The crystal structure of one-layer hydrate sodium brittle mica was determined and refined from single crystal X-ray data. Interlayer cations reside at the center of the distorted hexagonal cavities and are coordinated by the three inner basal oxygen atoms. The coordination of the interlayer cation is completed by three interlayer water molecules residing at the center of the interlayer region. The relative position of adjacent 2:1-layers thus is fixed by these octahedrally coordinated interlayer cations. Pseudo-symmetry leads to extensive twinning. In total five twin operations generate the same environment for the interlayer species and are energetically degenerate.

Kalo, Hussein; Milius, Wolfgang; Bru, Michael; Breu, Josef

2013-02-01

107

Protective effect of sivelestat sodium hydrate (ONO-5046) on ischemic spinal cord injury.  

PubMed

Prevention of paraplegia remains an important issue in repair of descending thoracic and thoracoabdominal aneurysms. Therefore, we investigated the protective effect of sivelestat sodium hydrate (ONO-5046) on ischemia-induced spinal cord damage in a rabbit model. Twenty New Zealand white rabbits were divided into two equal groups; ONO-5046 (1.6 mg/kg)+isotonic NaCl (30 ml) was administered selectively to the spinal cord via the lumbar arteries for the first 3 min during 30 min of infra-renal aorta clamping in the experimental group (group E), whereas NaCl was given alone in the control group (group C). Motor function of the lower limbs was assessed two days later by Tarlov criteria. The number of intact motor neurons in the anterior segment of the cord (L5 level) was counted after hematoxylin-eosin staining and the number of apoptotic motor neurons after TUNEL staining. Motor function of the lower limbs in group E was significantly better (P=0.003) than that in group C. The number of intact motor neurons was greater and of apoptotic motor neurons was less in group E than C. Selective infusion of sivelestat sodium hydrate directly into the spinal cord via the lumbar arteries significantly attenuated functional and morphological ischemia-induced spinal cord injury. PMID:19289399

Iwamoto, Satoshi; Higashi, Akihiro; Ueno, Tetsuya; Goto, Masamichi; Iguro, Yoshifumi; Sakata, Ryuzo

2009-03-16

108

THE INFLUENCE OF CaO REACIVITY ON FORMATION OF LOW-BASE CALCIUM SILICATE HYDRATES  

Microsoft Academic Search

The influence of CaO reactivity on the calcium sili cate hydrates formation in the CaO - SiO 2?nH 2O - H 2O system when molar CaO\\/SiO 2 ratio equal to 0.83 and 1.0 was determined. It was identified that in pure CaO - SiO 2?nH 2O - H 2O system with CaO\\/SiO 2 = 0.83, C-S-H(I) is rather stable and

K. Baltakys; E. PRICHOCKIENE

2010-01-01

109

Integrin-mediated Membrane Blebbing Is Dependent on Sodium-Proton Exchanger 1 and Sodium-Calcium Exchanger 1 Activity*  

PubMed Central

Integrin signaling and membrane blebbing modulate cell adhesion, spreading, and migration. However, the relationship between integrin signaling and membrane blebbing is unclear. Here, we show that an integrin-ligand interaction induces both membrane blebbing and changes in membrane permeability. Sodium-proton exchanger 1 (NHE1) and sodium-calcium exchanger 1 (NCX1) are membrane proteins located on the bleb membrane. Inhibition of NHE1 disrupts membrane blebbing and decreases changes in membrane permeability. However, inhibition of NCX1 enhances cell blebbing; cells become swollen because of NHE1 induced intracellular sodium accumulation. Our study found that NHE1 induced sodium influx is a driving force for membrane bleb growth, while sodium efflux (and calcium influx) induced by NCX1 in a reverse mode results in membrane bleb retraction. Together, these findings reveal a novel function for NHE1 and NCX1 in membrane blebbing and permeability, and establish a link between membrane blebbing and integrin signaling.

Yi, Yung-Hsiang; Chang, Yu-Sun; Lin, Chi-Hung; Lew, Tien-Shen; Tang, Chih-Yung; Tseng, Wei-Lien; Tseng, Ching-Ping; Lo, Szecheng J.

2012-01-01

110

Blood pressure changes in relation to sodium and calcium status in induced hyperinsulinemia.  

PubMed

Insulin increases renal sodium reabsorption which may contribute to hypertension. However, acute insulin administration may result in vasodilation. The aim of the present study was to investigate effects on blood pressure and alterations in ion status during hyperinsulinemia. Blood pressure and serum sodium and ionized calcium concentrations were measured before and at the end of euglycemic hyperinsulinemic clamp tests performed in 45 patients with essential hypertension. Both the systolic and the diastolic blood pressure decreased, by 4% (p < 0.05) and 3% (p < 0.05), respectively. Circulating ionized calcium concentration increased by 2% (p < 0.001), and the ratio between circulating sodium and ionized calcium concentrations decreased. The changes in circulating sodium concentration correlated to changes in systolic blood pressure (SBP; r = 0.36, p = 0.05). Both ionized calcium concentrations and the ratio between circulating sodium and ionized calcium concentrations correlated to changes in SBP during hyperinsulinemia (r = -0.41, p = 0.03, r = 0.56, p < 0.01, respectively). The changes in ion status were not significantly correlated to age, body mass index or insulin sensitivity. In conclusion, a more pronounced increase in circulating ionized calcium concentration and reduction in the ratio between sodium and ionized calcium concentrations was associated with a greater blood pressure decline during the hyperinsulinemic clamp test when performed in hypertensive patients. PMID:10855734

Haenni, A; Lind, L; Reneland, R; Lithell, H

2000-01-01

111

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

Microsoft Academic Search

Very high temperature, Ca-rich alkaline magma intruded an argillite formation at Colle Fabbri, Central Italy, producing cordierite-tridymite\\u000a metamorphism in the country rocks. An intense Ba-rich sulphate-carbonate-alkaline hydrothermal plume produced a zone of mineralization\\u000a several meters thick around the igneous body. Reaction of hydrothermal fluids with country rocks formed calcium-silicate-hydrate\\u000a (CSH), i.e., tobermorite-afwillite-jennite; calcium-aluminum-silicate-hydrate (CASH) cement phases - i.e., thaumasite,

Francesco Stoppa; Fernando Scordari; Ernesto Mesto; Victor V. Sharygin; Giorgio Bortolozzi

2010-01-01

112

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

SciTech Connect

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.

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

113

A calcium sensor in the sodium channel modulates cardiac excitability.  

PubMed

Sodium channels are principal molecular determinants responsible for myocardial conduction and maintenance of the cardiac rhythm. Calcium ions (Ca2+) have a fundamental role in the coupling of cardiac myocyte excitation and contraction, yet mechanisms whereby intracellular Ca2+ may directly modulate Na channel function have yet to be identified. Here we show that calmodulin (CaM), a ubiquitous Ca2+-sensing protein, binds to the carboxy-terminal 'IQ' domain of the human cardiac Na channel (hH1) in a Ca2+-dependent manner. This binding interaction significantly enhances slow inactivation-a channel-gating process linked to life-threatening idiopathic ventricular arrhythmias. Mutations targeted to the IQ domain disrupted CaM binding and eliminated Ca2+/CaM-dependent slow inactivation, whereas the gating effects of Ca2+/CaM were restored by intracellular application of a peptide modelled after the IQ domain. A naturally occurring mutation (A1924T) in the IQ domain altered hH1 function in a manner characteristic of the Brugada arrhythmia syndrome, but at the same time inhibited slow inactivation induced by Ca2+/CaM, yielding a clinically benign (arrhythmia free) phenotype. PMID:11807557

Tan, Hanno L; Kupershmidt, Sabina; Zhang, Rong; Stepanovic, Svetlana; Roden, Dan M; Wilde, Arthur A M; Anderson, Mark E; Balser, Jeffrey R

2002-01-24

114

Sodium Sulfate Hot Corrosion of Silicon Carbide Fiber-Reinforced Calcium Aluminosilicate.  

National Technical Information Service (NTIS)

The effects of sodium sulfate hot corrosion on the microstructure of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composite were investigated using optical microscopy, scanning electron microscopy (SEM) and x-ray diffracti...

M. A. Oppici

1995-01-01

115

Calcium transport through the luminal membrane of the distal tubule. I. Interrelationship with sodium  

Microsoft Academic Search

Calcium transport through the luminal membrane of the distal tubule. I. Interrelationship with sodium.Calcium (Ca2+) transport by isolated luminal membranes from rabbit renal distal tubule has been characterized. Ca2+ uptake by these membrane vesicles exhibited saturation kinetics. In the absence of sodium (Na+) in the incubation medium, a low affinity system was observed with a KmCa2+ of 2.83 0.64

Michele G Brunette; Johanne Mailloux; Daniel Lajeunesse

1992-01-01

116

Morphological control of calcium carbonate crystals by polyvinylpyrrolidone and sodium dodecyl benzene sulfonate  

Microsoft Academic Search

The crystallization of calcium carbonate was conducted by the reaction of sodium carbonate with calcium chloride in the presence of polyvinylpyrrolidone (PVP), sodium dodecylbenzene sulfonate (SDBS), or the mixture of PVP and SDBS, respectively. The morphology and polymorphism of these CaCO3 crystals were characterized with scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The results showed that the organic

Qiang Shen; Hao Wei; Ying Zhao; Du-Jin Wang; Li-Qiang Zheng; Duan-Fu Xu

2004-01-01

117

Novel technique for phosphorus recovery from aqueous solutions using amorphous calcium silicate hydrates (A-CSHs).  

PubMed

A novel technique for phosphorus (P) recovery from aqueous solutions was developed using amorphous calcium silicate hydrates (A-CSHs). A-CSHs, which have a high Ca/Si molar ratio of 2.0 or greater, could be synthesized using unlimitedly available, inexpensive materials such as siliceous shale and calcium hydroxide. A-CSHs showed high performance for P recovery from an anaerobic sludge digestion liquor (ASDL) and the synthetic model liquor (s-ASDL) containing 89mg PO4-P/L. After 20min mixing, 1.5g/L A-CSHs could remove approximately 69 and 73% PO4-P from ASDL and s-ASDL, respectively. By contrast, autoclaved lightweight concrete particles, which contained crystalline calcium silicate hydrates as a principal component, removed only 10 and 6% PO4-P from ASDL and s-ASDL, respectively, under the same experimental conditions. When A-CSHs were washed with deionized water to remove free Ca(OH)2, P removability was significantly improved (up to 82%) despite the reduction in the amount of Ca(2+) released. Unlike in the case of Ca(OH)2, nosignificant carbonate inhibition was observed with P removal by A-CSHs. Moreover, Premoved by A-CSHs showed better settleability, filterability, and dewaterability than Pprecipitated with conventional CaCl2 and Ca(OH)2. The present study demonstrated that A-CSHs have great potential as a novel, beneficial material for P recovery and recycling. PMID:23497975

Okano, Kenji; Uemoto, Masahide; Kagami, Jumpei; Miura, Keiichi; Aketo, Tsuyoshi; Toda, Masaya; Honda, Kohsuke; Ohtake, Hisao

2013-02-26

118

Phosphoprotein staining for sodium dodecyl sulfate-polyacrylamide gel electrophoresis using fluorescent reagent morin hydrate.  

PubMed

A fluorescence-based stain with 3,5,7,2',4'-pentahydroxyflavone (morin hydrate, MH) was designed to stain phosphoproteins in one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Al(3+) was applied as a "fixed bridge," providing an efficient energy transfer channel between phosphoprotein and MH, to produce a strong fluorescent complex for the determination of phosphoprotein. As little as 62.5ng of ?-casein (7 or 8 phosphates) and ?-casein (5 phosphates), 125ng of ovalbumin (2 phosphates), and ?-casein (1 phosphate) could be visualized with a wide linear dynamic range. In comparison with conventional methods, MH stain is a time-saving method that takes just 90min. It also has good compatibility with routine protein stainings such as Coomassie Brilliant Blue R (CBBR) and SYPRO Ruby for total protein analysis. PMID:23274386

Wang, Xu; Hwang, Sun-Young; Cong, Wei-Tao; Jin, Li-Tai; Choi, Jung-Kap

2012-12-28

119

Are micelles needed to form methane hydrates in sodium dodecyl sulfate solutions?  

PubMed

The possibility that methane hydrates form in sodium dodecyl sulfate (SDS) water solutions without the help of micelles formation has been investigated. To asses whether micelles are needed for the hydrate to form only one SDS molecule has been considered. To figure out the possible mechanism through which the SDS promotes the formation of methane clathrate the dynamics of CH(4) solvation in the presence and absence of the surfactant molecule is monitored. To carry out the dynamical calculations, the SDS-H(2)O, SDS-CH(4), and CH(4)-H(2)O interactions were described using a recently proposed model potential. The adopted model leverages both on the decomposition of the molecular polarizability in effective components associated with the interaction centers distributed on the molecular frame and on the use of an improved Lennard-Jones functional form to represent the effective pair interaction energies. Molecular dynamics simulations performed on such potential, contrary to some earlier assumptions, do not support mechanisms requiring the formation of micelles as suggested by the findings of more recent experiments. PMID:22448641

Albert, M; Costantini, A; Lagan, A; Pirani, F

2012-04-03

120

Effect of calcium, magnesium and sodium ions on in vitro nucleation of human gall bladder bile.  

PubMed Central

The effect of increasing the calcium, magnesium and sodium concentration in gall bladder bile samples from 21 patients with gall stones and nine controls on the in vitro rate of formation of cholesterol microcrystals and numbers of cholesterol microcrystals formed was examined. Addition of these cations to raise the mean maximum concentration of calcium ions to 19.8 mmol/l, of magnesium ions to 20 mmol/l and sodium ions to 998 mmol/l did not trigger nucleation in control bile samples or samples from patients with gall stones. Increasing the mean concentration of calcium ions to 8.6 mmol/l and of sodium to 320 mmol/l increased the numbers of cholesterol monohydrate crystals/0.1 mm3 counted by light polarisation phase contrast microscopy at the time of nucleation in samples from patients with gall stones from a median of 2 (range 1-10) in control portions to 18 (range 2-128) for calcium ions and 10 (range 2-141) for sodium ions (p less than 0.001). Calcium and magnesium ions were more effective than sodium ions, and calcium ions could increase crystal numbers at concentrations found in samples from patients with gall stones, median 4.6 mmol/l (range 2.7-16.9 mmol/l). The concentrations of calcium and magnesium present in bile may therefore influence the rate of development of gall stones. Images Fig. 1

Neithercut, W D

1989-01-01

121

Can the Sodium-Calcium Exchanger Initiate or Suppress Calcium Sparks in Cardiac Myocytes?  

PubMed Central

Positive feedback of Calcium (Ca)-induced Ca release is the mechanism of Ca spark formation in cardiac myocytes. To initiate this process, a certain amount of Ca in the cleft space is necessary. When the membrane potential becomes higher during excitation-contraction coupling, Ca can enter through both Ca current (ICaL) and sodium-calcium exchanger (NCX) and may activate ryanodine receptors to initiate a Ca spark. On the other hand, at the resting membrane potential (Vm ?80mV), NCX removes Ca from the cell (forward mode). If Ca released from the sarcoplasmic reticulum is quickly removed via forward mode NCX before Ca-induced Ca release starts, the Ca release becomes nonspark Ca leak. This would also be influenced bythe cleft/noncleft distribution of NCX, which is unknown. Using a physiologically detailed mathematical model of subcellular Ca cycling, we analyze how NCX strength and distribution alter Ca spark formation. During excitation-contraction coupling, most Ca sparks are induced by ICaL with very few due to NCX current. At the resting membrane potential if most NCX is localized to the cleft, spontaneous Ca sparks are significantly reduced.

Sato, Daisuke; Despa, Sanda; Bers, Donald M.

2012-01-01

122

The effect of dietary sodium on calcium metabolism in premenopausal and postmenopausal women  

Microsoft Academic Search

Objective: To investigate the effects of high and low sodium diets on urinary calcium, bone turnover and calcium absorption in pre and postmenopausal women. Design: Experimental, prospective and longitudinal study. Setting: Samples were taken at the hospital and the diets were followed at home. Subjects: Volunteers were recruited from the hospital and were either hospital staff or post-graduate students. No

CEL Evans; AY Chughtai; A Blumsohn; M Giles; R Eastell

1997-01-01

123

An electrokinetic study on a synthetic adsorbent of crystalline calcium silicate hydrate and its mechanism of endotoxin removal  

Microsoft Academic Search

A synthetic, disposable adsorbent of crystalline calcium silicate hydrate, LRA product by Advanced Minerals Corp., has been found highly effective for endotoxin removal from aqueous solutions. Endotoxin removal by this adsorbent is greatly enhanced by the addition of an electrolyte, such as NaCl or TrisHCl. The electrophoretic method has been used to study the mechanism of endotoxin adsorption. In many

Qun Wang; John P. Zhang; Timothy R. Smith; William E. Hurst; Thomas Sulpizio

2005-01-01

124

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

Microsoft Academic Search

The characteristics of silver-sodium ion exchange in standard commercial sodium-calcium-silicate glass are investigated using\\u000a mode spectroscopy. The activation energy of the process, the silver-sodium interdiffusion coefficient, and the dependence\\u000a of the maximal modulation of the refractive index on the silver nitrate concentration in the experimental salt bath are determined.\\u000a The data set presented here makes it possible to specify the

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

2010-01-01

125

Influences of additives on the gas hydrate cool storage process in a new gas hydrate cool storage system  

Microsoft Academic Search

Experimental research on the crystallization process of the gas hydrate HCFC141b is performed for this paper. The influences of different proportions of calcium hypochlorite or benzenesulfonic acid sodium salt on the crystallization process are studied. The results show that the degree of subcooling of formation is obviously decreased, and the formation rate of the gas hydrate is greatly accelerated by

Yuehong Bi; Tingwei Guo; Tingying Zhu; Liang Zhang; Lingen Chen

2006-01-01

126

Molecular dynamics study on the growth of structure I methane hydrate in aqueous solution of sodium chloride.  

PubMed

The structure, thermodynamic, and kinetic properties of methane hydrates formed from the aqueous solution of sodium chloride are investigated based on molecular dynamics simulations. A three-phase molecular model consisting of a slab of methane hydrate phase, a slab of liquid water containing sodium chloride, and a gas phase of methane molecules is used. The decrease in the three-phase coexisting temperatures (by 2-3 K) at different pressures (10-100 MPa) for aqueous NaCl solutions (about 2 mol %) confirms the thermodynamic inhibition of NaCl. The growth rate of methane hydrates in NaCl solution is found to be half to one-third of that in pure water. The kinetic inhibition of NaCl is found to be a result of the reduced water repelling at the growing interface due to the strong hydration of ions. Individual ions or NaCl ion pairs can replace water molecules to participate in the formation of the cage structures. The distortion of water cages due to the presence of ions may result in a reduced fraction of occupation of methane in the cage cavities. Our results provide useful insights into the mechanism of growth of methane hydrates in seawater and the desalination. PMID:23137227

Tung, Yen-Tien; Chen, Li-Jen; Chen, Yan-Ping; Lin, Shiang-Tai

2012-11-20

127

Inverse 31P ? 1H NMR cross-polarization in hydrated nanocrystalline calcium hydroxyapatite  

NASA Astrophysics Data System (ADS)

Hydrated nanocrystalline calcium hydroxyapatite was studied using unconventional solid-state NMR technique with cross-polarization from phosphorus-31 to protons (31P ? 1H CP) under magic-angle spinning (MAS). Two peaks were detected: at 0.0 ppm from structural hydroxyl groups and at 5.4 ppm from water. Their intensities were monitored as a function of the contact time. It was found that there were two types of water adsorbed on the crystal surface: typical strongly bound water and distinct, more mobile water associated with a particular 31P environment capable of fast spin-lattice relaxation in the rotating frame. Relative contents of protons in various material compartments were estimated.

Kolmas, Joanna; Kolodziejski, Waclaw

2012-12-01

128

The effect of the internal sodium concentration on calcium fluxes in isolated guinea-pig auricles  

PubMed Central

1. Calcium efflux from guinea-pig auricles followed saturation kinetics when [Ca]o and [Na]o were changed while the ratio [Ca]o/[Na]o2 was kept constant. The Michaelis constant, KmCa+Na = 40 mM, suggests that a hypothetical carrier system, responsible for sodiumcalcium exchange, is far from saturation with the inside concentrations of these ions. 2. [Na]i was altered in the auricles between 125 and 60 mM/kg fibre water while total cellular calcium concentration ([Ca]t) at the beginning of the influx period was not significantly different in the various groups of preparations. 3. 45Ca influx increased appreciably with increasing [Na]i. 45Ca influx from sodium-poor solution corresponded to an almost equal increase in [Ca]t, while [Ca]t did not change much in preparations loaded with 45Ca in Tyrode solution. When the sodium-activated fraction of calcium influx was plotted against [Na]i2 the resulting curve indicated saturation with KmNa = 3500 (mM [Na]i)2 and maximal influx rate, Ji, maxCa' = 135 mM/kg wet weight 10 min. 4. When the preparations were re-equilibrated for various times in normal Tyrode solution after [Na]i had been increased, both the sodium-activated component of calcium influx and [Na]i2 decreased with approximately the same rate constants. 5. Calcium efflux from auricles with high [Na]i was increased when it was measured in Tyrode solution while the efflux in sodium-poor solution was inhibited. 6. Auricles with increased [Na]i showed a positive inotropic contractile response. 7. The main conclusion reached by these experiments is that calcium influx is affected by [Na]i in a way which is compatible with a carrier-mediated sodiumcalcium exchange system.

Glitsch, H. G.; Reuter, H.; Scholz, H.

1970-01-01

129

Unique extraction behavior of americium and curium in a system of TBP and calcium nitrate hydrate melt  

NASA Astrophysics Data System (ADS)

Extraction of Am(III) and Cm(III) between tri-n-butyl phosphate solution and molten calcium nitrate hydrate Ca(NO3)2RH2O was investigated radiochemically. In the range of water content R = 3.5-8.0, the distribution ratio was found to increase with the decrease of water activity. The dependence of the distribution ratios on the water activity in the hydrate melt changes at around log aH2O = -0.4, which corresponds to R = 5.0. The extraction behavior of Am(III) and Cm(III) was systematically discussed with the reported data of trivalent lanthanides.

Okude, G.; Fujii, T.; Uehara, A.; Sekimoto, S.; Minato, K.; Yamana, H.

2010-03-01

130

Comparative Molecular Field Analysis of Benzothiazepine Derivatives: Mitochondrial Sodium Calcium Exchange Inhibitors as Antidiabetic Agents  

PubMed Central

Mitochondrial sodium calcium exchange inhibitors are novel agents in the treatment of type-II diabetes due to their glucose dependent efficacy. While the compounds of this class are expected to correct hyperglycemia, they do not lower basal blood glucose level, thus avoiding the serious consequences of hypoglycemia. The 3DQSAR analysis of benzothiazepines and their derivatives as mitochondrial sodium calcium exchange inhibitors was performed by comparative molecular field analysis to determine the structural factors required for the activity of these compounds. After performing a leave one out cross validation study, satisfactory results were obtained, with cross-validated q2 and conventional r2 values of 0.711 and 0.970, respectively. The results provided the tools for predicting the affinity of the related compounds, and guidance for the designing and synthesis of novel and potent mitochondrial sodium calcium exchange inhibitors as antidiabetic agents.

Dasoondi, A. S.; Singh, V.; Voleti, S. R.; Tiwari, Meena

2008-01-01

131

Comparative molecular field analysis of benzothiazepine derivatives: mitochondrial sodium calcium exchange inhibitors as antidiabetic agents.  

PubMed

Mitochondrial sodium calcium exchange inhibitors are novel agents in the treatment of type-II diabetes due to their glucose dependent efficacy. While the compounds of this class are expected to correct hyperglycemia, they do not lower basal blood glucose level, thus avoiding the serious consequences of hypoglycemia. The 3DQSAR analysis of benzothiazepines and their derivatives as mitochondrial sodium calcium exchange inhibitors was performed by comparative molecular field analysis to determine the structural factors required for the activity of these compounds. After performing a leave one out cross validation study, satisfactory results were obtained, with cross-validated q(2) and conventional r(2) values of 0.711 and 0.970, respectively. The results provided the tools for predicting the affinity of the related compounds, and guidance for the designing and synthesis of novel and potent mitochondrial sodium calcium exchange inhibitors as antidiabetic agents. PMID:20046710

Dasoondi, A S; Singh, V; Voleti, S R; Tiwari, Meena

132

The effect of high sodium intake on bone mineral content in rats fed a normal calcium or a low calcium diet  

Microsoft Academic Search

The effect of high sodium intake on bone mineral content of rats fed a normal (0.6% Ca) or a low (0.02% Ca) calcium diet was studied. Rats on a normal calcium diet given 1.8% sodium chloride to drink showed persistent and significant hypercalciuria and subnormal bone mineral content. Total calcium content of femur was significantly lower after 4 months (pp<0.001).

A. Y. S. Chan; P. Poon; E. L. P. Chan; S. L. M. Fung; R. Swaminathan

1993-01-01

133

Corrosion resistance of inconel 690 to sodium carbonate, calcium carbonate, and sodium meta silicate at 900 and 1100(degrees)C.  

National Technical Information Service (NTIS)

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 an...

K. J. Imrich

1997-01-01

134

Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines  

SciTech Connect

A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consistent way a different effect on the repassivation potential of Alloy 22 for calcium chloride solutions than for sodium chloride solutions.

Rebak, R B; Ilevbare, G O; Carranza, R M

2007-08-11

135

Hydration status and fluid and sodium balance in elite Canadian junior women's soccer players in a cool environment.  

PubMed

Dehydration can impair mental and on-field performance in soccer athletes; however, there is little data available from the female adolescent player. There is a lack of research investigating fluid and electrolyte losses in cool temperatures. Therefore, the purpose of this study was to investigate the pretraining hydration status, fluid balance, and sweat sodium loss in 34 female Canadian junior elite soccer athletes (mean age SD, 15.7 0.7 years) in a cool environment. Data were collected during two 90 min on-field training sessions (9.8 3.3 C, 63% 12% relative humidity). Prepractice urine specific gravity (USG), sweat loss (pre- and post-training body mass), and sweat sodium concentration (regional sweat patch method) were measured at each session. Paired t tests were used to identify significant differences between training sessions and Pearson's product moment correlation analysis was used to assess any relationships between selected variables (p ? 0.05). We found that 45% of players presented to practice in a hypohydrated state (USG > 1.020). Mean percent body mass loss was 0.84% 0.07% and sweat loss was 0.69 0.54 L. Although available during each training session, fluid intake was low (63.6% of players consumed <250 mL). Mean sweat sodium concentration was 48 12 mmolL?. Despite low sweat and moderate sodium losses, players did not drink enough to avoid mild fluid and sodium deficits during training. The findings from this study highlights the individual variations that occur in hydration management in athletes and thus the need for personalized hydration guidelines. PMID:22803782

Gibson, Jennifer C; Stuart-Hill, Lynneth A; Pethick, Wendy; Gaul, Catherine A

2012-07-17

136

Formation of hydroxyapatite in soils using calcium citrate and sodium phosphate for control of strontium migration.  

SciTech Connect

{sup 90}Sr contamination is a major problem at several U.S. sites. At some sites, {sup 90}Sr has migrated deep underground making site remediation difficult. In this paper, we describe a novel method for precipitation of hydroxyapatite, a strong sorbent for {sup 90}Sr, in soil. The method is based on mixing a solution of calcium citrate and sodium phosphate in soil. As the indigenous soil microorganisms mineralize the citrate, the calcium is released and forms hydroxyapatite. Soil, taken from the Albuquerque desert, was treated with a sodium phosphate solution or a sodium phosphate/calcium citrate solution. TEM and EDS were used to identify hydroxyapatite with CO{sub 3}{sup 2-} substitutions, with a formula of (Ca{sub 4.8}Na{sub 0.2})[(PO{sub 4}){sub 2.8}(CO{sub 3}){sub 0.2}](OH), in the soil treated with the sodium phosphate/calcium citrate solution. Untreated and treated soils were used in batch sorption experiments for Sr uptake. Average Sr uptake was 19.5, 77.0 and 94.7% for the untreated soil, soil treated with sodium phosphate, and soil with apatite, respectively. In desorption experiments, the untreated soil, phosphate treated soil and apatite treated soil released an average of 34.2, 28.8 and 4.8% respectively. The results indicate the potential of forming apatite in soil using soluble reagents for retardation of radionuclide migration.

Moore, Robert Charles; Hasan, Ahmed Ali Mohamed; Sanchez, Charles Anthony (University of Arizona, Yuma, AZ); Zhao, Hongting; Salas, Fred Manuel; Hasan, Mahmoud A. (Egyptian Atomic Energy Authority, Cairo, Egypt); Holt, Kathleen Caroline

2003-08-01

137

Calcium reduces the sodium permeability of luminal membrane vesicles from toad bladder. Studies using a fast-reaction apparatus  

PubMed Central

Regulation of the sodium permeability of the luminal membrane is the major mechanism by which the net rate of sodium transport across tight epithelia is varied. Previous evidence has suggested that the permeability of the luminal membrane might be regulated by changes in intracellular sodium or calcium activities. To test this directly, we isolated a fraction of the plasma membrane from the toad urinary bladder, which contains a fast, amiloride-sensitive sodium flux with characteristics similar to those of the native luminal membrane. Using a flow-quench apparatus to measure the initial rate of sodium efflux from these vesicles in the millisecond time range, we have demonstrated that the isotope exchange permeability of these vesicles is very sensitive to calcium. Calcium reduces the sodium permeability, and the half-maximal inhibitory concentration is 0.5 microM, well within the range of calcium activity found in cells. Also, the permeability of the luminal membrane vesicles is little affected by the ambient sodium concentration. These results, when taken together with studies on whole tissue, suggest that cell calcium may be an important regulator of transepithelial sodium transport by its effect on luminal sodium permeability. The effect of cell sodium on permeability may be mediated by calcium rather than by sodium itself.

1983-01-01

138

Addition of sodium hyaluronate and the effect on performance of the injectable calcium phosphate cement  

Microsoft Academic Search

An injectable calcium phosphate cement (CPC) with porous structure and excellent anti-washout ability was developed in the\\u000a study. Citric acid and sodium bicarbonate were added into the CPC powder consisting of tetracalcium phosphate (TTCP) and dicalcium\\u000a phosphate dihydrate (DCPD) to form macro-pores, then different concentrations of sodium hyaluronate (NaHA) solution, as liquid\\u000a phase, was added into the cement to investigate

Dan Kai; Dongxiao Li; Xiangdong Zhu; Lei Zhang; Hongsong Fan; Xingdong Zhang

2009-01-01

139

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

Microsoft Academic Search

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

K. Subha; P. Varalakshmi

1992-01-01

140

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

Microsoft Academic Search

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 20mg of CaO sample was mixed with about 2g of Al2O3 particles and packed in the reactor and allowed to

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

2011-01-01

141

Natural organic matter and the formation of calcium-silicate-hydrates in lime-stabilized smectites: A thermal analysis study  

Microsoft Academic Search

Processes accounting for the negative effects of soil organic matter on strength development in lime-stabilized soils are not clearly understood. We used heat-flow differential scanning calorimetry and thermogravimetry to elucidate how natural organic matter (NOM) content and source influences the formation of calcium-silicate-hydrates (CSHs) in lime-stabilized smectites. The formation of CSH, was strongly correlated with strength (r?0.95) and decreased with

Omar R. Harvey; John P. Harris; Bruce E. Herbert; Eric A. Stiffler; Stephen P. Haney

2010-01-01

142

The DASH Diet and Sodium Reduction Improve Markers of Bone Turnover and Calcium Metabolism in Adults1,2  

Microsoft Academic Search

Dietary strategies to prevent and treat osteoporosis focus on increased intake of calcium and vitamin D. Modification of whole dietary patterns and sodium reduction may also be effective. We examined the effects of two dietary patterns and three sodium levels on bone and calcium metabolism in a randomized feeding study. A total of 186 adults, aged 23-76 y, participated. After

Pao-Hwa Lin; Fiona Ginty; Lawrence J. Appel; Mikel Aickin; Arline Bohannon; Patrick Garnero; Denis Barclay; Laura P. Svetkey

143

Nanostructured calcium silicate hydrate seeds accelerate concrete hardening: a combined assessment of benefits and risks.  

PubMed

Nanotechnology creates new possibilities to control and improve material properties for civil infrastructure. Special focus in this area is put on Portland cement and gypsum. Together their annual production is by far larger than for any other material worldwide. Nanomodification of these materials can be done during the few hours between dissolution and hardening, especially by nucleation of the re-crystallization with suitable colloids. Here we report first results in homogeneous seeding of the precipitation of calcium silicate hydrates within a real Portland cement composition. The occupational safety during the production phase and during mixing of concrete paste is addressed in detail by in vivo testing. We perform 5-day inhalation with 21-day recovery in rats and analyze organ-specific toxicity and 71 endpoints from bronchoalveolar lavage (BALF) and blood. In BALF parameters, no test-related changes were observed, indicating the generally low toxicity of the test material. Some mild lesions were observed in larynx level. In the lungs, all animals of the 50 mg/m concentration group revealed a minimal to mild increase in alveolar macrophages, which recovered back to control level. PMID:22466068

Bru, Michael; Ma-Hock, Lan; Hesse, Christoph; Nicoleau, Luc; Strauss, Volker; Treumann, Silke; Wiench, Karin; Landsiedel, Robert; Wohlleben, Wendel

2012-03-31

144

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

SciTech Connect

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.

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

145

Hydrothermal Formation Of Hemi-hydrate Calcium Sulfate Whiskers In The Presence Of Additives  

SciTech Connect

The influence of addictives on the hydrothermal formation of hemi-hydrate calcium sulfate (CaSO{sub 4{center_dot}}0.5H{sub 2}O) whiskers were discussed in this paper, using CaCl{sub 2} and Na{sub 2}SO{sub 4} as the reactants. The presence of NaCl, CaCl{sub 2} or Na{sub 2}SO{sub 4} increased the concentrations of Ca{sup 2+} and SO{sub 4}{sup 2-}, leading to the formation of CaSO{sub 4{center_dot}}0.5H{sub 2}O whiskers with aspect ratio lower than 50. The one dimensional growth of CaSO{sub 4{center_dot}}0.5H{sub 2}O whiskers was enhanced in water with no additives owing to the low super-saturation, leading to the formation of uniform whiskers with a length of 200-2000 {mu}m and an aspect ratio higher than 100.

Luo, K. B. [Department of Chemical Engineering, Kunming University of Science and Technology, Kunming 650224 (China); Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Li, C. M.; Li, H. P.; Ning, P. [Department of Chemical Engineering, Kunming University of Science and Technology, Kunming 650224 (China); Xiang, L. [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

2010-11-24

146

Effect of Sodium Fluoride on Calcium Metabolism of Human Beings  

Microsoft Academic Search

ALTHOUGH bones of human subjects become abnormally dense after several years of industrial exposure to fluorides1,2, no work on the effect of fluoride on calcium balance of human beings has been carried out. Roholm1 and others2 have shown that the severity of skeletal changes is correlated approximately with the extent and duration of exposure to fluoride : moderate exposure resulting

Clayton Rich; John Ensinck

1961-01-01

147

Sodium\\/calcium selectivity of cloned calcium T-type channels  

Microsoft Academic Search

We studied the peculiarities of permeability with respect to the main extracellular cations, Na+ and Ca2+, of cloned low-threshold calcium channels (LTCCs) of three subtypes, Cav3.1 (?1G), Cav3.2 (? 1H), and Cav3.3 (?1I), functionally expressed in Xenopus oocytes. In a calcium-free solution containing 100 mM Na+ and 5 mM calcium-chelating EGTA buffer (to eliminate residual concentrations of Ca2+) we observed

A. K. Shcheglovitov; Ya. M. Shuba

2006-01-01

148

Changes in the Concentration of Potassium Sodium and Calcium as the Result of Endurance Effort.  

National Technical Information Service (NTIS)

The potassium, sodium and calcium levels in the venous blood serum were measured in 122 persons, before and after endurance efforts of varying intensity (80 min track and field exercises, gymnastics, 1500 m swimming and bus driving). The potassium and sod...

E. Preisler R. Kadza

1974-01-01

149

Allosteric cotransport of sodium, chloride, and calcium by the intestine of freshwater prawns  

Microsoft Academic Search

Summary The apical membrane of the intestinal epithelium of the freshwater prawn,Macrobrachium rosenbergii, has been found to possess an apparently unique allosteric carrier mechanism for the simultaneous cotransport of sodium, chloride, and calcium from mucosal solution to cytosol. Influxes of the two monovalent ions individually were sigmoidal functions of their respective luminal concentrations, and their kinetics followed the Hill equation

Gregory A. Ahearn

1978-01-01

150

Method of Manufacturing a Saponified Mixture of Sodium and Calcium Lubricating Grease and Standard Lubricating Grease.  

National Technical Information Service (NTIS)

The report discusses a method for manufacturing a saponification mixed sodium calcium lubricating grease characterized by the fact that first runnings of fatty acids, last running of fatty acids and lime are mixed together and heated to 75C, the lye is sl...

E. Boeck

1972-01-01

151

Sodium Sulfate Corrosion of Silicon Carbide Fiber-Reinforced Calcium Aluminosilicate Glass-Ceramic Matrix Composites.  

National Technical Information Service (NTIS)

Hot corrosion effects of Sodium Sulfate (NaSO4) coated Calcium Aluminosilicate (CAS)/Silicon Carbide (SiC) reinforced glass-ceramic matrix composite were investigated using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-r...

P. J. Newton

1994-01-01

152

Fermentation of cucumbers brined with calcium chloride instead of sodium chloride  

Technology Transfer Automated Retrieval System (TEKTRAN)

Generation of waste water containing sodium chloride from cucumber fermentation tank yards could be eliminated if cucumbers were fermented in brines that did not contain this salt. To determine if this is feasible, cucumbers were fermented in brines that contained only calcium chloride to maintain f...

153

Sodium, Calcium, and Magnesium in Tissues of the Gerbil, Meriones Unguiculatus Exercised to Exhaustion.  

National Technical Information Service (NTIS)

Calcium is decreased in the heart and kidneys of exercise-exhausted gerbils. Magnesium is decreased in liver, kidney, heart and lungs but increased in muscle of these animals. Sodium is markedly decreased in the kidneys of the exhausted gerbils. (Author)

C. G. Wilber

1967-01-01

154

Drastic difference in porous structure of calcium alginate microspheres prepared with fresh or hydrolyzed sodium alginate.  

PubMed

Fresh or hydrolyzed sodium alginate was used as a material for preparing calcium alginate microspheres, and a drastic difference in porous structure was observed between them, even though the other materials and the preparation method except for the sodium alginate were exactly the same. When fresh sodium alginate was used, nonporous microspheres were obtained. In contrast, when 82-day-hydrolyzed sodium alginate, whose molecular weight became 7% of the molecular weight of the fresh sodium alginate, was used, porous microspheres with 6.5 times larger BET surface area were obtained. XPS studies indicated that the atomic ratio of Ca, the crosslinker of the alginic acid polymer, was almost the same in both cases. Therefore, the difference in porous structure was not attributed to the amount of crosslinking points, but to the low-molecular-weight compounds formed by hydrolysis, and they would work as pore-generating agents. PMID:21872260

Akamatsu, Kazuki; Maruyama, Kaho; Chen, Wei; Nakao, Aiko; Nakao, Shin-ichi

2011-08-11

155

Selective Measurement of Calcium and Sodium Ion Conductance Using Sub-Micropipette Probes with Ion Filters  

NASA Astrophysics Data System (ADS)

Selective ion currents in aqueous calcium chloride and sodium chloride solutions with concentrations of up to 1.0 M were observed with sub-micropipettes in which poly(vinyl chloride) (PVC) films containing ionophores selectively filtered cations. Calcium bis[4-(1,1,3,3-tetramethyl butyl)phenyl] phosphate (HDOPP-Ca) and bis[(12-crown-4)methyl]-2-dodecyl-2-methylmalonate [bis(12-crown-4)] were used as the ionophores to filter calcium and sodium ions, respectively. The selective ion current was observed using a low-current detection system developed from scanning tunneling microscopy. The approximate linear relationship between the ion concentration and ion current suggests that the sub-micropipette probe can be used to detect the intracellular local concentration of a specific ion up to 1.0 M.

Deng, Xiao Long; Takami, Tomohide; Son, Jong Wan; Kawai, Tomoji; Park, Bae Ho

2012-02-01

156

[Sodium, potassium and calcium content in regional dishes consumed in Sonora, Mexico].  

PubMed

The content of sodium, potassium and calcium was determined in 15 regional dishes, by atomic absorption spectrophotometry. The Na:K ratio was high in most of the dishes due to the high sodium content and low content of potassium found. The higher sources of the studied minerals were "tortilla de harina" with 1,372.8 mg/100 g of sodium; "chorizo con papas" with 466 mg/100 g of potassium, and "calabacitas con queso" with 244.1 mg/100 g of calcium. Two of the dishes considered as desserts, "capirotada" and "arroz con leche" showed the lowest Na:K ratio (0.66 and 0.81, respectively). PMID:2133188

Grijalva Haro, M I; Valencia, M E; Wyatt, J

1990-06-01

157

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

PubMed Central

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.

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

2011-01-01

158

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

Microsoft Academic Search

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.

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

1984-01-01

159

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

Microsoft Academic Search

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 (CS) 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.

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

1999-01-01

160

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

PubMed

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

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

2013-05-21

161

Plasma membrane calcium pump and sodiumcalcium exchanger in maintenance and control of calcium concentrations in platelets  

Microsoft Academic Search

The purpose of this research was to elucidate the activity of the mechanisms responsible for control of cytosolic calcium concentration in platelets by modeling the time-course of the concentration changing in response to discharge of the intracellular stores or store-operated calcium entry (SOCE). The parameters estimated as a result of model fitting to experimental data are related to physiological or

Alfonsas Juka

2010-01-01

162

The role of the sodium-calcium exchanger for calcium extrusion in coronary arteries  

Microsoft Academic Search

Calcium ionophores, such as the A23187, cause endothelium-dependent relaxation of arterial strips with intact endothelium, whereas the effect of the ionophore should result from the combination of a relaxation caused by the endothelium-dependent factors and of a contraction of the smooth muscles. In addition, the application of a calcium ionophore to a strip of pig coronary arteries without endothelium does

Stphane Budel; Jean-Louis Beny

2000-01-01

163

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

Microsoft Academic Search

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

C Freidin

1998-01-01

164

Effect of water content on the solid-state stability in two isomorphic clathrates of cephalosporin: cefazolin sodium pentahydrate (alpha form) and FK041 hydrate.  

PubMed

This study clearly demonstrates that clathrated water molecules can contribute to both chemical stabilization and destabilization of clathrates. The solid-state stabilities for two isomorphic clathrates of cephalosporin, cefazolin sodium and FK041, were investigated in terms of the effects of water content. The isomorphic ranges of water content were estimated to be 3.5-5 mol/mol for alpha-form cefazolin sodium and 2-4 mol/mol for FK041 hydrate. Upon the isomorphic dehydration, alpha-form cefazolin sodium was destabilized as the water content decreased below 4.25 mol/mol owing to the disruption of hydrogen bonding network in lattice channels. In this case, the hydration of clathrated water up to 4.25 mol/mol contributed to the physical and chemical stability of the crystals. On the contrary, the isomorphic hydration in FK041 hydrate contributed to the chemical destabilization owing to the high water activity. The difference in water activity between alpha-form cefazolin sodium and FK041 hydrate could be attributed to the size of water channels. PMID:12045330

Mimura, Hisashi; Gato, Katsuhiko; Kitamura, Satoshi; Kitagawa, Teruyuki; Kohda, Shigetaka

2002-06-01

165

Sodium\\/potassium\\/calcium exchanger 3 is regulated by the steroid hormones estrogen and progesterone in the uterus of mice during the estrous cycle  

Microsoft Academic Search

Plasma membrane sodium\\/calcium exchangers are an important component of intracellular calcium homeostasis and electrical conduction. A member of the family of potassium-dependent sodium\\/calcium exchangers, NCKX3 (SLC24A3) plays a critical role in the transport of an intracellular calcium and potassium ion in exchange for four extracellular sodium ions. NCKX3 mRNA transcripts are particularly abundant in brain and smooth muscle, but many

Hyun Yang; Geun-Shik Lee; Yeong-Min Yoo; Kyung-Chul Choi; Eui-Bae Jeung

2009-01-01

166

Potassium, Calcium, Magnesium, and Sodium Levels in Biological Samples of Hypertensive and Nonhypertensive Diabetes Mellitus Patients  

Microsoft Academic Search

There is accumulating evidence that the metabolism of several essential elements is altered in diabetes mellitus and that\\u000a these nutrients might have specific roles in the pathogenesis and progress of this disease. The aim of the present study was\\u000a to compare the level of essential elements, potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na), in biological samples\\u000a (whole blood,

Hassan Imran Afridi; Tasneem Gul Kazi; Naveed Kazi; Mohammad Khan Jamali; Mohammad Bilal Arain; Nusrst Jalbani; Raja Adil Sarfaraz; Afzal Shah; Ghulam Abbas Kandhro; Abdul Qadir Shah; Jameel Ahmed Baig

2008-01-01

167

Polyunsaturated Fatty Acids Modulate Sodium and Calcium Currents in CA1 Neurons  

Microsoft Academic Search

Recent evidence indicates that long-chain polyunsaturated fatty acids (PUFAs) can prevent cardiac arrhythmias by a reduction of cardiomyocyte excitability. This was shown to be due to a modulation of the voltage-dependent inactivation of both sodium (INa) and calcium (ICa) currents. To establish whether PUFAs also regulate neuronal excitability, the effects of PUFAs on INa and ICa were assessed in CA1

M. Vreugdenhil; C. Bruehl; R. A. Voskuyl; J. X. Kang; A. Leaf; W. J. Wadman

1996-01-01

168

The effects of sodium hypochlorite and calcium hydroxide on tissue dissolution and root canal cleanliness  

Microsoft Academic Search

Summary In this in vitro study, we investigated the efficacy of sodium hypochlorite (NaOCl) and calcium hydroxide (Ca(OH) 2 ) in dissolving necrotic tissue and cleaning root canals. In the first part of the study, 0.5% NaOCl solution and Ca(OH) 2 paste and solution were tested with samples of necrotic bovine muscle in different treat- ment modes and for different

M. Turkun; T. Cengiz

1997-01-01

169

Sodium sulfate hot corrosion of silicon carbide fiber-reinforced calcium aluminosilicate. Master`s thesis  

Microsoft Academic Search

The effects of sodium sulfate hot corrosion on the microstructure of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composite were investigated using optical microscopy, scanning electron microscopy (SEM) and x-ray diffraction (XRD). Hot corrosion of samples at 900 deg C for 50 hours in both air and argon was investigated. SEM and XRD investigations of the sample exposed in air

Oppici

1995-01-01

170

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

Microsoft Academic Search

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 300600C. The sorbent particle size has a slight effect on

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

1996-01-01

171

The interrelationships between sodium ion, calcium transport and oxygen utilization in the isolated chick chorioallantoic membrane  

Microsoft Academic Search

Summary The interrelationships between sodium ion, calcium transport and oxygen utilization have been investigated in the chick chorioallantoic membrane. The oxygen uptakes of the two surface layers of the tissue, the ectoderm and the endoderm, were separated into their basal, Na+ dependent and Ca++ dependent components. The endoderm has a basal rate of respiration of 3.6 liters O2\\/cm2\\/hr and a

James C. Garrison; A. Raymond Terepka

1972-01-01

172

Detoxification of Cyanide in a Gold Processing Plant Tailings Water Using Calcium and Sodium Hypochlorite  

Microsoft Academic Search

In laboratory experiments, cyanide in waste water from the Muteh gold mine in Iran was oxidized by sodium and calcium hypochlorite\\u000a to cyanate (CNO?), which is 1,000 times less environmentally hazardous than cyanide. Experiments were conducted using waste water containing\\u000a 270mg\\/L cyanide over a pH range of 613 and temperatures between 25 and 50C. Cyanide was removed completely at a

A. Khodadad; P. Teimoury; M. Abdolahi; A. Samiee

2008-01-01

173

Effects of sodium fluoride, vitamin D, and calcium on cortical bone remodeling in osteoporotic patients  

Microsoft Academic Search

SummaryThe purpose of this histomorphometric study of iliac bone biopsies from 10 postmenopausal osteoporotic patients was to describe\\u000a the effects of sodium fluoride (combined with calcium and vitamin D) on remodeling in cortical bone after 6 months and after\\u000a 5 years of tretment. Biopsies had been fixed in absolute methanol, embedded undecalcified in methylmetacrylate, and cut on\\u000a a heavy-duty microtome.

Jakob Kragstrup; Zhao Shijie; Leif Mosekilde; Flemming Melsen

1989-01-01

174

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

Microsoft Academic Search

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

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

1994-01-01

175

Diamide stimulates calcium-sodium exchange in dog red blood cells  

SciTech Connect

Calcium influx can be stimulated in dog red blood cells by preexposure to diamide under certain conditions. Diamide-activated calcium influx resembles swelling-induced {sup 45}Ca{sup 2+}-Na{sup +} exchange in several respects. These include saturation of calcium influx at external calcium levels >0.5 mM, suppression of calcium influx by external sodium, and inhibition by quinidine. The ability of diamide to stimulate this transport pathway depends critically on the ionic composition of the medium in which the cells are bathed at the time of diamide exposure. The effect is greatest if the diamide preincubation is conducted in a hypotonic lithium chloride medium containing at least 1 {mu}M calcium. Stimulation of Ca{sup 2+}-Na{sup +} exchange is seen at diamide concentrations that are lower than those reported to cause major spectrin cross-linking, glutathione depletion, Ca{sup 2+}-ATPase inhibition, or ion channel formation. The results suggest that dog red cells have a large latent capacity for Ca{sup 2+}-Na{sup +} exchange.

Parker, J.C. (Univ. of North Carolina, Chapel Hill (USA))

1987-10-01

176

Sodium and potassium salts of dichloroisocyanuric acid and their hydrates as antimicrobials agents studied by 35Cl-NQR spectroscopy and DFT calculations  

NASA Astrophysics Data System (ADS)

The electronic structure of dichloroisocyanuric acid derivatives was analysed by 35Cl-NQR spectroscopy and DFT calculations. Here we concentrate our attention on three different factors: type of metallic substituent (sodium and potassium), temperature of the sample (liquid nitrogen and room) and degree of hydration (an amount of water molecules attached to analysed compounds). In particular, all the variations in 35Cl-NQR frequencies upon hydration of salts containing sodium and potassium ions are explained as a consequence of H-bonds formation and accompanied effects of charge redistribution. Our studies can be useful in searching for the derivatives of dichloroisocyanuric acid revealing higher antimicrobial activity.

Walczak, A.; Brycki, B.; Kaczmarek, M.; Poleshchuk, O. Kh.; Ostafin, M.; Nogaj, B.

2006-06-01

177

Calcium and sodium transport and vitamin D metabolism in the spontaneously hypertensive rat.  

PubMed Central

Serum ionized calcium levels are lower and immunoreactive parathyroid hormone levels are higher in the spontaneously hypertensive (SH) rat than in the normotensive Wistar-Kyoto (WKy) control. We postulated that there is either a defect in the regulation of vitamin D metabolism by parathyroid hormone or that the gut target organ for vitamin D in the SH rat is unresponsive. To test these hypotheses we measured serum concentrations of vitamin D metabolites and intestinal transport of calcium and sodium. Compared with that of WKy controls, in vitro calcium transport by duodenal sacs of the SH rat was decreased (P less than 0.001) at 5 wk, before the development of hypertension, and at 12 wk, after hypertension was well established. When measured in vivo in the most proximal 20 cm of small intestine, maximum velocity (Vmax) for calcium transport was decreased (P less than 0.05) and net absorption of sodium and water was increased (P less than 0.05) in SH rats as compared with WKy rats. Vmax for calcium transport was also decreased (P less than 0.05) in the most distal 20 cm of small intestine of SH rats, but net sodium and water transport were the same in SH and WKy rats. At 12 wk, serum concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] was the same in both SH and WKy groups, but its precursor, 25-hydroxycholecalciferol, was increased (P less than 0.05) in the SH rat. We conclude that in the SH rat: (a) the concentration of 1,25-(OH)2D3 is inappropriately low in relation to the elevated immunoreactive parathyroid hormone and the depressed calcium absorption, suggesting a defect in the regulation of vitamin D metabolism; and (b) the depressed calcium absorption, in the setting of normal concentrations of [1,25-(OH)2D3], demonstrates unresponsiveness of the gut to vitamin D and may explain in part the low serum ionized calcium found in earlier studies. The presence of these abnormalities before we found a significant difference in blood pressure suggests that they may be causal, not secondary, to the hypertension. Images

Schedl, H P; Miller, D L; Pape, J M; Horst, R L; Wilson, H D

1984-01-01

178

DIFFERENTIAL MEMBRANOLYTIC EFFECTS OF MICROCRYSTALLINE SODIUM URATE AND CALCIUM PYROPHOSPHATE DIHYDRATE  

PubMed Central

Microcrystals of sodium urate produced direct lysis of erythrocyte membranes, as had been described previously for silica. Calcium pyrophosphate crystals induced modest erythrocyte hemolysis, also, and time-course experiments showed a markedly different reaction curve from those produced by silica and urate. Polyvinylpyridine-N-oxide, a strong hydrogen acceptor, was bound from solution to urate and silica, but not to calcium pyrophosphate crystals; this compound effectively blocked urate and silica, but not calcium pyrophosphate or control hemolysis. Dextran and heparin inhibited urate-but not silica-induced hemolysis. If erythrocyte and lysosome membranes react similarly to these particles, then the absence of phagosomes in gouty synovial fluid leukocytes, and the presence of these structures in pseudogout, may be explained.

Wallingford, Walter R.; McCarty, Daniel J.

1971-01-01

179

Effect of calcium chloride on the hydration and leaching of lead-retarded cement  

SciTech Connect

The effect of adding CaCl[sub 2] to ordinary portland cement containing 10% (by weight) of a synthetic lead hydroxide waste has been investigated using differential thermal analysis, conduction calorimetry, and by analyzing solutions extracted from mixes during the early stages of hydration. Lead wastes are known to retard initial cement hydration reactions, and for the waste loading used in these experiments the peak in the heat of hydration curve was delayed from 8.7 to 172 h. The addition of CaCl[sub 2] reduced this retarding effect but was associated with a decrease in the overall extent of cement hydration, particularly at high CaCl[sub 2] concentrations. The acceleration induced is associated with lower concentrations of hydroxyl ions in solution. This reduces dissolution and subsequent adsorption of Pb(OH)[sub 3][sup [minus

Cheeseman, C.R.; Asavapisit, S. (Imperial College of Science, Technology and Medicine, London (United Kingdom))

1999-06-01

180

The effects of epidermal hydration and sodium reabsorption on palmar skin potential  

Microsoft Academic Search

Describes 2 factors important in measurements of palmar skin potentials: (a) Epidermal hydration, which occurs when aqueous solutions with low salt content are applied to the skin, promotes swelling of the epidermis and closure of the sweat gland pores. Poral closure, in turn, reduces the measured potential by increasing the resistance between the electrode and the negative potential in the

Don C. Fowles; P. H. Venables

1970-01-01

181

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

SciTech Connect

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.

Imrich, K.J.

1997-01-29

182

Hydration, hydration, hydration.  

PubMed

Throughout the world, large numbers of manual workers perform physically demanding labour in conditions of high environmental heat stress. Although the importance of adequate hydration in combating heat stress is universally recognized, studies in a range of worker groups have demonstrated a disturbingly poor hydration level in a high proportion of at-risk workers. Management of work in hot environments traditionally focuses on environmental monitoring, while strategies to promote and ensure good hydration behaviour are often haphazard at best. An example is given of simple guidelines for adequate and appropriate fluid intake and practical recommendations to foster compliance. PMID:20008893

Miller, Veronica S; Bates, Graham P

2009-12-15

183

Stability and rheology of emulsions containing sodium caseinate: combined effects of ionic calcium and non-ionic surfactant  

Microsoft Academic Search

We have investigated the effect of the combination of ionic calcium and non-ionic surfactant (Tween 20) on the visual creaming behaviour and rheology of n-tetradecane-in-water emulsions (4wt% protein, 30vol% oil, mean droplet diameter 0.4?m) prepared at pH 6.8 with sodium caseinate. Varying concentrations of ionic calcium, expressed as the calcium\\/caseinate molar ratio R, were incorporated before homogenization, and varying concentrations

Eric Dickinson; Stewart J. Radford; Matt Golding

2003-01-01

184

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

Microsoft Academic Search

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 1mmoll -1 ) were used to delineate the mechanism of sodium influx in Daphnia magna. Lowering water pH severely inhibited sodium

Chris N. Glover; Chris M. Wood

2005-01-01

185

Prediction of compatibility between ozagrel sodium preparation for injection and calcium on the basis of the solubility product.  

PubMed

The purpose of the study was to evaluate the compatibility of ozagrel sodium solution and calcium-containing transfusions using solubility product constants. We calculated the solubility product constant of mixtures of ozagrel sodium and calcium chloride and evaluated the compatibility of ozagrel sodium solution (both the original and generic products) with calcium chloride solution using a light obscuration particle counter. Various volumes of ozagrel solution were added to the calcium solutions to make final ozagrel concentrations of 0, 0.8, 1.6, 2.0, 2.4, 3.2 and 4.0 mmol/L. The solutions were gently agitated and stored at 25 and 40C. The ozagrel concentration, calcium ion concentration and number of microparticles were measured. The solubility product constants obtained were 11.8910(-9) mol(3)/L(3) (at 25C) and 7.8210(-9) mol(3)/L(3) (40C). The number of insoluble microparticles was significantly increased when the ionic product was larger than the solubility product constant. In all ozagrel sodium products, the number of insoluble microparticles was within the allowable range according to the Japanese Pharmacopoeia. These results suggest that mixing ozagrel sodium with calcium-containing products is safe and without appreciable risk of incompatibility under clinical conditions. PMID:23449252

Tange, Mio; Yoshida, Miyako; Hazekawa, Mai; Haraguchi, Tamami; Nakai, Yuka; Uchida, Takahiro

2013-03-01

186

Influence of hydration variables on the properties of South African calcium\\/siliceous-based material  

Microsoft Academic Search

This study presents findings from experiments on the preparation and characterization of locally available fly ash, quicklime\\u000a and the CaO\\/fly ash sorbent, synthesized using the atmospheric hydration process. The CaO was obtained from calcination of\\u000a limestone in a laboratory kiln at a temperature of 900C. The sorbents were prepared under different hydration conditions:\\u000a CaO\\/fly ash weight ratio (11 to 13),

D. O. Ogenga; Z. O. Siagi; M. S. Onyango; M. Mbarawa

2009-01-01

187

Sodium sulfate hot corrosion of silicon carbide fiber-reinforced calcium aluminosilicate. Master`s thesis  

SciTech Connect

The effects of sodium sulfate hot corrosion on the microstructure of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composite were investigated using optical microscopy, scanning electron microscopy (SEM) and x-ray diffraction (XRD). Hot corrosion of samples at 900 deg C for 50 hours in both air and argon was investigated. SEM and XRD investigations of the sample exposed in air revealed a complex mixture of wollastonite, nepheline and albite whereas exposure in argon showed pseudowollastonite, nepheline and calcium sulfide. It was observed that the presence of Na2SO4 enhanced the oxidation of the silicon carbide fiber to silica which further reacted to form the products of corrosion.

Oppici, M.A.

1995-03-01

188

Endurance Exercise Training Reduces Cardiac Sodium/Calcium Exchanger Expression in Animals Susceptible to Ventricular Fibrillation  

PubMed Central

Aim: Increased sodium/calcium exchanger activity (NCX1, an important regulator of cardiomyocyte cystolic calcium) may provoke arrhythmias. Exercise training can decrease NCX1 expression in animals with heart failure improving cytosolic calcium regulation, and could thereby reduce the risk for ventricular fibrillation (VF). Methods: To test this hypothesis, a 2-min coronary occlusion was made during the last minute of exercise in dogs with healed myocardial infarctions; 23 had VF (S, susceptible) and 13 did not (R, resistant). The animals were randomly assigned to either 10-week exercise training (progressively increasing treadmill running; S n?=?9; R n?=?8) or 10-week sedentary (S n?=?14; R n?=?5) groups. At the end of the 10-week period, the exercise?+?ischemia test provoked VF in sedentary but not trained susceptible dogs. On a subsequent day, cardiac tissue was harvested and NCX1 protein expression was determined by Western blot. Results: In the sedentary group, NCX1 expression was significantly (ANOVA, P?calcium regulation and could thereby reduce the risk for sudden death following myocardial infarction.

Kukielka, Monica; Holycross, Bethany J.; Billman, George E.

2010-01-01

189

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

ERIC Educational Resources Information Center

|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)|

Smith, Robert L.; And Others

1988-01-01

190

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

NASA Astrophysics Data System (ADS)

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.

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

191

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

NASA Astrophysics Data System (ADS)

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.

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

2000-05-01

192

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

SciTech Connect

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.

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

193

A calcium-activated sodium conductance contributes to the fertilization potential in the egg of the nemertean worm Cerebratulus lacteus.  

PubMed

The fertilization potential of the egg of the nemertean worm Cerebratulus lacteus consisted of a rapid shift from a resting potential of about -65 mV to a peak of about +44 mV; the peak was followed by a positive plateau at about +24 mV, lasting an average of 80 min. Reduction of extracellular calcium reduced the peak of the fertilization potential, indicating that the peak resulted from a calcium conductance, while reduction of extracellular sodium reduced the plateau potential, indicating that the plateau resulted from a sodium conductance. Microinjection of ethylene glycol bis(beta-aminoethyl ether)-N,N'-tetraacetic acid (EGTA) or 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)/CaBAPTA buffers, having a free calcium concentration of less than or equal to about 0.1 microM lowered the fertilization potential plateau. Injection of a BAPTA/CaBAPTA mixture with a free calcium concentration of about 1 microM resulted in a prolonged positive potential at the level of the fertilization potential plateau. These observations indicated that the fertilization potential of the Cerebratulus egg depended on a calcium-activated sodium conductance. The plateau potential was reduced little, if any, when calcium-free seawater was perfused through the bath during the fertilization potential; nor was it reduced in seawater containing cadmium. These observations suggested the possibility that intracellular calcium stores could be important in producing the fertilization potential. PMID:3091428

Kline, D; Jaffe, L A; Kado, R T

1986-09-01

194

Hydration products of FBC wastes as SO 2 sorbents: comparison between ettringite and calcium hydroxide  

Microsoft Academic Search

Fluidized bed combustion (FBC) enables the in situ capture of SO2, but generates large amounts of wastes whose composition and physico-chemical properties make both landfilling and reuse in traditional fields of application (e.g., cement and concrete industries) problematic. Reactivation by water hydration of the desulphurizing ability of these residues is considered a viable mean for their recycling: besides Ca(OH)2, this

Fabio Montagnaro; Marianna Nobili; Piero Salatino; Antonio Telesca; Gian Lorenzo Valenti

2008-01-01

195

Calcium hydroxide saturation factors in the pore solution of hydrated portland cement fly ash pastes  

SciTech Connect

The portlandite saturation factors in the pore solution of hydrated portland cement paste and changes related to the addition of two types of fly ash have been studied. Small additions (15 wt%) of fly ash increase portlandite supersaturation at early ages, whereas larger additions reduce it, relative to the plain cement. At later ages, portlandite undersaturation is observed despite the continued presence of free portlandite in the paste as observed by SEM.

Goni, S.; Lorenzo, M.P.; Guerrero, A.; Hernandez, M.S. [CSIC, Madrid (Spain). Inst. of Construction Science Eduardo Torroja

1996-04-01

196

The effect of sodium chloride on the dissolution of calcium silicate hydrate gels  

Microsoft Academic Search

The use of cement based materials will be widespread in the long-term management of radioactive materials in the United Kingdom. One of the applications could be the Nirex reference vault backfill (NRVB) as an engineered barrier within a deep geological repository. NRVB confers alkaline conditions, which would provide a robust chemical barrier through the control of the solubility of some

J.. Hill; A. W. Harris; M. Manning; A. Chambers; S. W. Swanton

2006-01-01

197

Experimental observations on the competing effect of tetrahydrofuran and an electrolyte and the strength of hydrate inhibition among metal halides in mixed CO 2 hydrate equilibria  

Microsoft Academic Search

In the present work, experimental data on the equilibrium conditions of mixed CO2 and THF hydrates in aqueous electrolyte solutions are reported. Seven different electrolytes (metal halides) were used in this work namely sodium chloride (NaCl), calcium chloride (CaCl2), magnesium chloride (MgCl2), potassium bromide (KBr), sodium fluoride (NaF), potassium chloride (KCl), and sodium bromide (NaBr). All equilibrium data were measured

Khalik M. Sabil; Vicente R. Romn; Geert-Jan Witkamp; Cor J. Peters

2010-01-01

198

Solvent effects and hydration of a tripeptide in sodium halide aqueous solutions: an in silico study.  

PubMed

In this work we are trying to gain insight into the mechanisms of ion-protein interactions in aqueous media at the molecular scale through fully atomistic molecular dynamics simulations. We present a systematic molecular simulation study of interactions of sodium and halide ions with a trialanine peptide in aqueous sodium halide solutions with different salts concentrations (0.20, 0.50, 1.0 and 2.0 M). Each simulation covers more than fifty nanoseconds to ensure the convergence of the results and to enable a proper determination of the tripeptide-ion interactions through the potentials of mean force. Changes in ion densities in the vicinity of different peptide groups are analysed and implications for the tripeptide conformations are discussed. PMID:17925969

Fedorov, Maxim V; Goodman, Jonathan M; Schumm, Stephan

2007-07-31

199

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

PubMed Central

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 (NCKX16). 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.

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

2012-01-01

200

Calmodulin and calcium differentially regulate the neuronal Nav1.1 voltage-dependent sodium channel.  

PubMed

Mutations in the neuronal Nav1.1 voltage-gated sodium channel are responsible for mild to severe epileptic syndromes. The ubiquitous calcium sensor calmodulin (CaM) bound to rat brain Nav1.1 and to the human Nav1.1 channel expressed by a stably transfected HEK-293 cell line. The C-terminal region of the channel, as a fusion protein or in the yeast two-hybrid system, interacted with CaM via a consensus C-terminal motif, the IQ domain. Patch clamp experiments on HEK1.1 cells showed that CaM overexpression increased peak current in a calcium-dependent way. CaM had no effect on the voltage-dependence of fast inactivation, and accelerated the inactivation kinetics. Elevating Ca(++) depolarized the voltage-dependence of fast inactivation and slowed down the fast inactivation kinetics, and for high concentrations this effect competed with the acceleration induced by CaM alone. Similarly, the depolarizing action of calcium antagonized the hyperpolarizing shift of the voltage-dependence of activation due to CaM overexpression. Fluorescence spectroscopy measurements suggested that Ca(++) could bind the Nav1.1 C-terminal region with micromolar affinity. PMID:21726526

Gaudioso, Christelle; Carlier, Edmond; Youssouf, Fahamoe; Clare, Jeffrey J; Debanne, Dominique; Alcaraz, Gisle

2011-06-25

201

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

SciTech Connect

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.

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

1996-11-01

202

Sodium  

MedlinePLUS

Sodium What is sodium? It is a mineral found naturally in food. Why do we need it? Our bodies need sodium to maintain ... salt) per day How can you control your sodium intake? Read the Nutrition Facts Label to look ...

203

Study on Molecular Dynamics Simulation of Calcium Silicate Hydrate (CSH) Gels  

Microsoft Academic Search

\\u000a C-S-H gels-the main cement hydration product, have an important impact on the properties of cement and caused a wide range\\u000a of study on it. Simulation technology of molecular dynamics is summarized, the basic principles of molecular dynamics and\\u000a simulation of molecular dynamics of C-S-H gels are introduced, and development trend about simulation of molecular dynamics\\u000a of C-S-H gel is finally

Peng Hu; Wei Dai

2011-01-01

204

Storage of Low-Temperature Heat in Salt-Hydrate Melts: Calcium Chloride Hexahydrate.  

National Technical Information Service (NTIS)

Calcium chloride hexahydrate melts at 29.8 exp 0 C. Its heat of fusion is 170 J/g or 71.7 kWh/m exp 3 of solution. In the temperature interval 20 to 30 exp 0 C, it has a heat content comparable to a temperature increase from 20 to 90 exp 0 C in the equal ...

B. Carlsson H. Stymne G. Wettermark

1978-01-01

205

The mechanism by which cytoplasmic protons inhibit the sodium-calcium exchanger in guinea-pig heart cells.  

PubMed Central

1. We recorded cardiac sodium-calcium exchange current (INa-Ca) in giant excised membrane patches obtained from cardiac myocytes of the adult guinea-pig. 2. Rapid changes in ion concentrations on the cytoplasmic side of the excised membrane patch were produced using a modified oil-gate bath. 3. Sodium-calcium exchange current was activated by step increases in sodium concentration on the cytoplasmic side of the membrane ([Na+]i), which led to an increase in outward INa-Ca to a new steady-state level. The [Na+]i required to half-maximally activate the sodium-calcium exchange current (K1/2) was 21 mM. 4. Step increases in cytoplasmic calcium concentration ([Ca2+]i) stimulated the [Na+]i-activated INa-Ca up to 1 microM [Ca2+]i, then inhibited the exchange current at very high [Ca2+]i (1 mM). 5. A step decrease in cytoplasmic pH from 7.2 to 6.4 (increase in [H+]i) produced a biphasic but monotonic decrease in INa-Ca. Alkalinization of cytoplasmic pH from 7.2 to 8.0 caused a large, biphasic increase in INa-Ca. 6. When INa-Ca was activated by a step increase in [Na+]i and [H+]i was simultaneously increased, the outward current rose to a peak and then declined to a low steady level. The peak current seen was always less than the maximum current produced by an identical elevation of [Na+]i at constant pHi. This reduction in peak outward current reflected a rapid 'primary' inhibition of the sodium-calcium exchange by protons. The decay of the sodium-calcium exchange current following the peak was slow and corresponded to the time course of the onset of a 'secondary' proton block. 7. Rapid primary inhibition of the sodium-calcium exchanger could also be produced by cytoplasmic acidification in the absence of cytoplasmic sodium. The primary blockade was revealed when a subsequent increase in [Na+]i activated INa-Ca and a smaller peak outward current was observed. Secondary inhibition of the sodium-calcium exchanger was not, however, produced by cytoplasmic acidification in the absence of cytoplasmic sodium. Regardless of the duration of exposure to elevated [H+]i, the 'secondary' block by protons was still seen on activation of INa-Ca by increased [Na+]i as a gradual reduction of outward current amplitude. 8. Treatment of the sodium-calcium exchanger with the proteolytic enzyme alpha-chymotrypsin largely removed its sensitivity to protons. 9. We conclude that the action of alpha-chymotrypsin on the monomeric sodium-calcium exchange protein is in part to remove a proton-sensitive regulatory component(s) or render the regulation ineffective.(ABSTRACT TRUNCATED AT 400 WORDS)

Doering, A E; Lederer, W J

1993-01-01

206

X-ray crystal structure and vibrational spectra of hydrazides and their metal complexes. Part I. Catena-poly[di-?-aqua-(?-maleic hydrazidato- O)sodium] hydrate  

Microsoft Academic Search

The catena-poly[di-?-aqua-(?-maleic hydrazidato-O)sodium] hydrate, [Na(MH) (H2O)2]nH2O is examined using single crystal X-ray diffraction analysis. The crystals are monoclinic, space group C2\\/c, with a=14.321(4), b=16.114(5), c=6.547(1) , ?=104.11(2) and Z=4. In title complex, each sodium ion is coordinated by two oxygen atoms of two water molecules, one oxygen atom of the maleic hydrazidato, two oxygen atoms of two water molecules from

Barbara Morzyk-Ociepa

2007-01-01

207

Effect of potassium sodium tartrate and sodium citrate on the preparation of {alpha}-calcium sulfate hemihydrate from flue gas desulfurization gypsum in a concentrated electrolyte solution  

SciTech Connect

Flue gas desulfurization (FGD) gypsum mainly composed of calcium sulfate dihydrate (DH) was used as a raw material to obtain alpha-calcium sulfate hemihydrate ({alpha}-HH) through dehydration in a Ca-Mg-K-Cl-solution medium at 95{sup o}C under atmospheric pressure. The effects of potassium sodium tartrate and sodium citrate on the preparation of alpha-HH in the electrolyte solution were investigated. The results revealed that the addition of potassium sodium tartrate (1.0 x 10{sup -2} - 2.5 x 10{sup -2}M) decreased the dehydration rate of FGD gypsum and increased the length/width (l/w) ratio of {alpha}-HH crystals, which could yield unfavorable strength properties. Addition of sodium citrate (1.0 x 10{sup -5} - 2.0 x 10{sup -5}M) slightly increased the dehydration rate of FGD gypsum and decreased the l/w ratio of {alpha}-HH crystals, which could be beneficial to increase strength. However, it also led to a partial formation of anhydrite (AH) crystals. AH was also the only dehydration product when the concentration of sodium citrate increased to 1.0 x 10{sup -4}M. Therefore, sodium citrate rather than potassium sodium tartrate could be used as an additive in Ca-Mg-K-Cl electrolyte solutions if alpha-HH with a shorter l/w ratio is the desired product from FGD gypsum dehydration. The concentration of sodium citrate should be properly controlled to reduce the formation of AH.

Shen, Z.X.; Guan, B.H.; Fu, H.L.; Yang, L.C. [Zhejiang University, Hangzhou (China). Dept. of Environmental Engineering

2009-12-15

208

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

PubMed

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? 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? 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?, respectively. PMID:24056355

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

2013-09-19

209

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

PubMed Central

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? 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? 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?, respectively.

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

2013-01-01

210

Storage of low-temperature heat in salt-hydrate melts: Calcium chloride hexahydrate  

Microsoft Academic Search

Topics covered include: storage of low-temperature heat in melts; chloride hexahydrate as a heat storage medium; methods of adapting CaCl2.6H2O for use as a heat storage medium-investigations of the chemical solubility properties of the CaCl2; H2O system; heat transfer characteristics of a heat of fusion storage system based on calcium chloride hexahydrate; and the development and construction of a heat

B. Carlsson; H. Stymne; G. Wettermark

1978-01-01

211

Thermal Conductivity of Fibre Reinforced Porous Calcium Silicate Hydrate-based Composites  

Microsoft Academic Search

Steady-state thermal conductivity measurements of the cellulose fibre reinforced calcium silicate insulation boards were carried out. After exclusion of the effects caused by the enthalpy flow and the possible non-linear moisture content distribution the effective thermal conductivity-moisture content relations were determined from the measured apparent thermal conductivity values. The achieved moisture dependences of the thermal conductivity have had in the

Olga Koronthalyova; Peter Matiasovsky

2003-01-01

212

Thermodynamics of calcium chloride in highly concentrated aqueous solution and in hydrated crystals  

SciTech Connect

Measured values of the pressure of H[sub 2]O over saturated solutions in equilibrium with the dihydrate, tetrahydrate or hexahydrate of CaCl[sub 2] are converted to osmotic coefficients and compared with literature values for solutions of smaller molality. It is found that the osmotic coefficient is constant, within the uncertainty, from about 7 mol-kg[sup [minus]1] to saturation at all temperatures from 25 to 100[degrees]C. From this simple approximation, the activity coefficient is calculated for high molalities and at saturation. By combination of these results with other established data, entropies and Gibbs energies of formation are calculated for the crystalline hydrates of CaCl[sub 2]. 10 refs., 1 fig., 3 tabs.

Pitzer, K.S.; Yuwen Shi (Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley (United States))

1993-02-01

213

Ranolazine antagonizes the effects of increased late sodium current on intracellular calcium cycling in rat isolated intact heart.  

PubMed

Pathological conditions, including ischemia and heart failure, are associated with altered sodium channel function and increased late sodium current (I(Na,L)), leading to prolonged action potential duration, increased intracellular sodium and calcium concentrations, and arrhythmias. We used anemone toxin (ATX)-II to study the effects of increasing I(Na,L) on intracellular calcium cycling in rat isolated hearts. Cardiac contraction was abolished using paralytic agents. Ranolazine (RAN) was used to inhibit late I(Na). Hearts were loaded with fluo-4-acetoxymethyl ester, and myocyte intracellular calcium transients (CaTs) were measured using laser scanning confocal microscopy. ATX (1 nM) prolonged CaT duration at 50% recovery in hearts paced at a basal rate of 2 Hz and increased the sensitivity of the heart to the development of calcium alternans caused by fast pacing. ATX increased the time required for recovery of CaT amplitude following a previous beat, and ATX induced spontaneous calcium release waves during rapid pacing of the heart. ATX prolonged the duration of repolarization from the initiation of the activation to terminal repolarization in the pseudo-electrocardiogram. All actions of ATX were both reversed and prevented by subsequent or prior exposure, respectively, of hearts to RAN (10 microM). Most importantly, the increased vulnerability of the heart to the development of calcium alternans during rapid pacing was reversed or prevented by 10 microM RAN. These results suggest that enhancement of I(Na,L) alters calcium cycling. Reduction by RAN of I(Na,L)-induced dysregulation of calcium cycling could contribute to the antiarrhythmic actions of this agent in both reentrant and triggered arrhythmias. PMID:19675298

Wasserstrom, J Andrew; Sharma, Rohan; O'Toole, Matthew J; Zheng, Jiabo; Kelly, James E; Shryock, John; Belardinelli, Luiz; Aistrup, Gary L

2009-08-12

214

Haemorrhagic effects of sodium heparin and calcium heparin prophylaxis in patients undergoing mastectomy.  

PubMed

In a double-blind prospective clinical trial 75 consecutive patients undergoing mastectomy were randomly allocated to one of three groups. Twenty-five patients received perioperative anti-thromboembolic therapy with sodium heparin and 25 with calcium heparin. The remaining 25 patients were given anti-embolism stockings but no heparin. The total postoperative blood loss and period of drainage did not differ between the two groups given heparin, but a total of 10 of these 50 patients suffered haemorrhagic complications in the form of severe bruising or haematoma postoperatively. Of the patients given no heparin, none suffered haemorrhagic complications and the blood loss following the first 24-hour postoperative period was significantly less than in the groups given heparin. PMID:2681717

Lee, R E; Ho, K N; Karran, S J; Taylor, I

1989-06-01

215

DELIQUESCENCE BEHAVIOR AND CHEMICAL STABILITY OF VITAMIN C FORMS (ASCORBIC ACID, SODIUM ASCORBATE, AND CALCIUM ASCORBATE) AND BLENDS  

Microsoft Academic Search

The stability and type of vitamin C added to foods is important for enhancing product quality, label claims, and shelf-life. To improve understanding of stability, the effects of deliquescence, storage RH, formulation, and addition of ascorbyl palmitate and dehydroascorbic acid on degradation of vitamin C at 25C were studied. Individual vitamin C forms (ascorbic acid, sodium and calcium ascorbate) and

Ashley N. Hiatt; Mario G. Ferruzzi; Lynne S. Taylor; Lisa J. Mauer

2010-01-01

216

Deliquescence Behavior and Chemical Stability of Vitamin C Forms (Ascorbic Acid, Sodium Ascorbate, and Calcium Ascorbate) and Blends  

Microsoft Academic Search

The stability and type of vitamin C added to foods is important for enhancing product quality, label claims, and shelf-life. To improve understanding of stability, the effects of deliquescence, storage relative humidity (RH) formulation, and addition of ascorbyl palmitate and dehydroascorbic acid on degradation of vitamin C at 25C were studied. Individual vitamin C forms (ascorbic acid, sodium, and calcium

Ashley N. Hiatt; Mario G. Ferruzzi; Lynne S. Taylor; Lisa J. Mauer

2011-01-01

217

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

Microsoft Academic Search

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).

V. R. Wenner

1958-01-01

218

Cardiac sodium-calcium exchange and efficient excitation-contraction coupling: implications for heart disease.  

PubMed

Cardiovascular disease is a leading cause of death worldwide, with ischemic heart disease alone accounting for >12% of all deaths, more than HIV/AIDS, tuberculosis, lung, and breast cancer combined. Heart disease has been the leading cause of death in the United States for the past 85 years and is a major cause of disability and health-care expenditures. The cardiac conditions most likely to result in death include heart failure and arrhythmias, both a consequence of ischemic coronary disease and myocardial infarction, though chronic hypertension and valvular diseases are also important causes of heart failure. Sodium-calcium exchange (NCX) is the dominant calcium (Ca2+) efflux mechanism in cardiac cells. Using ventricular-specific NCX knockout mice, we have found that NCX is also an essential regulator of cardiac contractility independent of sarcoplasmic reticulum Ca2+ load. During the upstroke of the action potential, sodium (Na+) ions enter the diadic cleft space between the sarcolemma and the sarcoplasmic reticulum. The rise in cleft Na+, in conjunction with depolarization, causes NCX to transiently reverse. Ca2+ entry by this mechanism then "primes" the diadic cleft so that subsequent Ca2+ entry through Ca2+ channels can more efficiently trigger Ca2+ release from the sarcoplasmic reticulum. In NCX knockout mice, this mechanism is inoperative (Na+ current has no effect on the Ca2+ transient), and excitation-contraction coupling relies upon the elevated diadic cleft Ca2+ that arises from the slow extrusion of cytoplasmic Ca2+ by the ATP-dependent sarcolemmal Ca2+ pump. Thus, our data support the conclusion that NCX is an important regulator of cardiac contractility. These findings suggest that manipulation of NCX may be beneficial in the treatment of heart failure. PMID:23224894

Goldhaber, Joshua I; Philipson, Kenneth D

2013-01-01

219

The calcium response to the excitotoxin kainate is amplified by subsequent reduction of extracellular sodium.  

PubMed

The relation between intracellular and extracellular [Na+] and [Ca2+] and membrane potential during stimulation of non-N-methyl-D-aspartate glutamate receptors has been studied in cerebellar granule cells using the fluorescent indicators SBFI, fura-2 and the bisoxonol membrane potential probe DiBaC4(3). Kainate increased both [Ca2+]i (intracellular [Ca2+]) and [Na+]i (intracellular [Na+]) and depolarized the membrane. This elevation of [Ca2+]i was only partially dependent on the presence of extracellular Na+ at the time of kainate addition. Removal of extracellular Na+ itself had a very minor effect on the [Ca2+]i or membrane potential of unstimulated cells. If extracellular Na+ was removed (in order to reverse the [Na+] gradient) or its concentration reduced during stimulation with kainate, the membrane depolarization recovered as expected. However, the intracellular level of sodium recovered only very slowly and the [Ca2+]i rose sharply, rather than recovering as might be expected on repolarization of depolarized cells possessing voltage sensitive calcium channels. This effect of extracellular [Na+] reduction on [Ca2+]i was mimicked by ouabain, another agent that causes accumulation of [Na+] in cells. These results suggest that Na+/Ca2+ exchange may play a major role in calcium homeostasis in stimulated cells, and that the levels of Na+ inside and outside the cell are critical in determining the effect of receptor stimulation on the intracellular [Ca2+]. PMID:8544981

Courtney, M J; Enkvist, M O; Akerman, K E

1995-10-01

220

Atomic-absorption spectrometric determination of calcium, magnesium and potassium in leaf samples after decomposition with molten sodium hydroxide.  

PubMed

The decomposition of standard leaf samples of varied origin and nature by fusion with sodium hydroxide in an open system has been studied. The use of sodium nitrate as an auxiliary agent facilitated the mineralization of most of the samples. The solutions obtained were analysed for calcium, magnesium and potassium by flame atomic-absorption spectrometry. The method is fast and quite precise, with absolute standard deviations of 0.04-0.13, 0.002-0.03 and 0.04-0.12% for calcium, magnesium and potassium contents of O.8-5.0, 0.13-0.48 and 0.36-2.2% respectively. The limits of detection (mug/ml) in the determination step were 0.10 for calcium, 0.011 for magnesium, and 0.09 for potassium. PMID:18965244

Adelantado, J V; Martinez, V P; Garcia, A P; Reig, F B

1991-09-01

221

No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse.  

PubMed

Plaque 'calcium-fluoride-like' (CaF(2)-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 microg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF(2)-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF(2)-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF(2)-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF(2)-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF(2)-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. PMID:20185917

Vogel, G L; Tenuta, L M A; Schumacher, G E; Chow, L C

2010-02-24

222

[SEM, XRD and FTIR investigation on crystal growth of calcium oxalate modulated by sodium tartrate].  

PubMed

Crystallization of calcium oxalate (CaOxa) was investigated in the presence of sodium tartrate (Na2 tart) of different concentration in a gel system by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. It was found that in the presence of a low concentration of Na2tart (0.01 mol x L(-1)), calcium oxalate monohydrate (COM) is the dominant crystal phase. The percentage of calcium oxalate dihydrate (COD) is less than 5%. In the XRD pattern the main diffraction peaks are (101), (020), and (202) planes of COM crystals. In the FTIR spectrum, the main asymmetric carbonyl stretching band nu(as) (COO-) and the metal-carboxylate stretch nu(s) (COO-) of COM occur at 1 618 and 1 317 cm(-1), respectively. With the concentration of Na2 tart increasing to 0. 10 and 0. 50 mol x L(-1), the percentage of COD crystals increases to 10% and 50%, respectively, and the surface area of COM crystals decreases. The diffraction peaks that assigned to the (200), (211), (411), and (213) planes of COD crystals become stronger and stronger. The temperature can influence the modulation of Na2 tart in terms of the phase composition and morphology of CaOxa crystals. As the temperature decreases, the percentage of COD increases. At a higher temperature beyond 47 degrees C, COM is the dominant phase; but COM is dominant when the temperature is lower than 27 degrees C. The nu(as) (COO-) and nu(s), (COO-) of COD crystals occur at 1 647.6 and 1 327.7 cm(-1), respectively. PMID:16883858

Zheng, Hui; Chen, Cun-Yuan; Ouyang, Jian-Ming

2006-05-01

223

Histrionicotoxins: effects on binding of radioligands for sodium, potassium, and calcium channels in brain membranes.  

PubMed

A series of eight histrionicotoxins and two synthetic analogs inhibit binding of [3H]batrachotoxinin B to sites on voltage dependent sodium channels in brain membranes. Perhydrohistrionicotoxin (IC50 0.33 microM) and octahydrohistrionicotoxin (IC50 1.2 microM) are comparable in activities to potent local anesthetics. Histrionicotoxin (IC50 17 microM) and the other histrionicotoxins are much less potent. The histrionicotoxins also inhibit binding of [3H]phencyclidine to putative potassium channels in brain membranes. Histrionicotoxin (IC50 15 microM) and the other histrionicotoxins are much more potent than perhydrohistrionicotoxin (IC50 200 microM), but are at least 200-fold less potent than phencyclidine. The histrionicotoxins enhance binding of [3H]nitrendipine to sites on calcium channels in brain membranes, with the exception of perhydrohistrionicotoxin, which inhibits binding. Structure activity relationships at these channel sites and at the sites for noncompetitive blockers on the nicotinic acetylcholine receptor channel (AChR) complex differ. The histrionicotoxins are more potent at the sites on the AChR complex than at sites on other channels with the exception of perhydrohistrionicotoxin, which has comparable potency at the AChR complex and sodium channels. PMID:2446155

Lovenberg, T; Daly, J W

1986-11-01

224

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

PubMed Central

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 (2200 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.

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

2008-01-01

225

Use of calcium caseinate in association with lecithin for masking the bitterness of acetaminophen-Comparative study with sodium caseinate.  

PubMed

Owing to a variety of structural and functional properties, milk proteins are steadily studied for food and pharmaceutical applications. In the present study, calcium caseinate in association with lecithin was firstly investigated in order to encapsulate the acetaminophen through spray-drying for taste-masking purpose for pediatric medicines. A 2(4)-full factorial design revealed that the spray flow, the calcium caseinate amount and the lecithin amount had significant effects on the release of drug during the first 2min. Indeed, increasing the spray flow and/or the calcium caseinate amount led to increase the released amount, whereas increasing the lecithin amount decreased the released amount. The "interaction" between the calcium caseinate amount and the lecithin amount was also shown to be statistically significant. The second objective was to compare the efficiency of two caseinate-based formulations, i.e. sodium caseinate and calcium caseinate, on the taste-masking effect. The characteristics of spray-dried powders determined by SEM and DSC were shown to depend on the caseinate/lecithin proportion rather than the type of caseinate. Interestingly, calcium caseinate-based formulations were found to lower the released amount of drug during the early time to a higher extent than sodium caseinate-based formulations, which indicates better taste-masking efficiency. PMID:24016744

Hoang Thi, Thanh Huong; Lemdani, Mohamed; Flament, Marie-Pierre

2013-09-07

226

Conformational flexibility of voltage gated dihydropyridine sensitive calcium channel in hydrated DMPC bilayer.  

PubMed

We have built a model for Ca2+ channel using amino acid sequence from S3 helix of the fourth internal repeat of alpha 1 subunit of dihydropyridine sensitive calcium channel from rabbit skeletal muscle, on the basis of X-ray crystallographic data on four helix bundle. The assembling of the geometry of the pore was achieved using a sixteen residues peptide fragment from short SSI/II loop (residues 1010-1025) which had F1013 and E1014 residues, considered to be important for the drug induced activity of the channel. This had hairpin bend between F1013 to W1016. The drug 2,6-dimethyl 3,5-dicarbomethoxy-4 (2-nitrobenzyl) 1,4 dihydropyridine (DHP) (nifedipine), which is a calcium channel inhibitor used in the treatment of cardiovascular diseases, was introduced, interacting with these two residues via Ca2+ ion. Two more Ca2+ ions were introduced in the pore. The model was incorporated in the bilayer of 36 dimyristoyl phosphatidyl choline (DMPC) molecules with 1201 water molecules and simulated for 200 picoseconds (ps) after equilibration for 120 ps. We also simulated the channel model in vacuum and in aqueous environment for comparison. The latter was unstable after 120 ps. The geometric parameters of the pore are analysed by MOLMOL, PCURVE 3.1 and a special program ANHELIX developed by us. Stability of the pore dimensions during simulations is discussed in this paper. PMID:10410460

Kothekar, V; Gupta, D

1998-10-01

227

Bones and Crohn's: No benefit of adding sodium fluoride or ibandronate to calcium and vitamin D  

PubMed Central

AIM: To compare the effect of calcium and cholecalciferol alone and along with additional sodium fluoride or ibandronate on bone mineral density (BMD) and fractures in patients with Crohns disease (CD). METHODS: Patients (n =148) with reduced BMD (T-score < -1) were randomized to receive cholecalciferol (1000 IU) and calcium citrate (800 mg) daily alone(group A, n = 32) or along with additional sodium fluoride (25 mg bid) (group B, n = 62) or additional ibandronate (1 mg iv/3-monthly) (group C, n = 54). Dual energy X-ray absorptiometry of the lumbar spine (L1-L4) and proximal right femur and X-rays of the spine were performed at baseline and after 1.0, 2.25 and 3.5 years. Fracture-assessment included visual reading of X-rays and quantitative morphometry of vertebral bodies (T4-L4). RESULTS: One hundred and twenty three (83.1%) patients completed the first year for intention-to-treat (ITT) analysis. Ninety two (62.2%) patients completed the second year and 71 (47.8%) the third year available for per-protocol (PP) analysis. With a significant increase in T-score of the lumbar spine by +0.28 0.35 [95% confidence interval (CI): 0.162-0.460, P < 0.01], +0.33 0.49 (95% CI: 0.109-0.558, P < 0.01), +0.43 0.47 (95% CI: 0.147-0.708, P < 0.01) in group A, +0.22 0.33 (95% CI: 0.125-0.321, P < 0.01); +0.47 0.60 (95% CI: 0.262-0.676, P < 0.01), +0.51 0.44 (95% CI: 0.338-0.682, P < 0.01) in group B and +0.22 0.38 (95% CI: 0.111-0.329, P < 0.01), +0.36 0.53 (95% CI: 0.147-0.578, P < 0.01), +0.41 0.48 (95% CI: 0.238-0.576, P < 0.01) in group C, respectively, during the 1.0, 2.25 and 3.5 year periods (PP analysis), no treatment regimen was superior in any in- or between-group analyses. In the ITT analysis, similar results in all in- and between-group analyses with a significant in-group but non-significant between-group increase in T-score of the lumbar spine by 0.38 0.46 (group A, P < 0.01), 0.37 0.50 (group B, P < 0.01) and 0.35 0.49 (group C, P < 0.01) was observed. Follow-up in ITT analysis was still 2.65 years. One vertebral fracture in the sodium fluoride group was detected. Study medication was safe and well tolerated. CONCLUSION: Additional sodium fluoride or ibandronate had no benefit over calcium and cholecalciferol alone in managing reduced BMD in CD.

Klaus, Jochen; Reinshagen, Max; Herdt, Katharina; Schroter, Christoph; Adler, Guido; von Boyen, Georg BT; von Tirpitz, Christian

2011-01-01

228

SIK1 is part of a cell sodium-sensing network that regulates active sodium transport through a calcium-dependent process  

PubMed Central

In mammalian cells, active sodium transport and its derived functions (e.g., plasma membrane potential) are dictated by the activity of the Na+,K+-ATPase (NK), whose regulation is essential for maintaining cell volume and composition, as well as other vital cell functions. Here we report the existence of a salt-inducible kinase-1 (SIK1) that associates constitutively with the NK regulatory complex and is responsible for increases in its catalytic activity following small elevations in intracellular sodium concentrations. Increases in intracellular sodium are paralleled by elevations in intracellular calcium through the reversible Na+/Ca2+ exchanger, leading to the activation of SIK1 (Thr-322 phosphorylation) by a calcium calmodulin-dependent kinase. Activation of SIK1 results in the dephosphorylation of the NK ?-subunit and an increase in its catalytic activity. A protein phosphatase 2A/phosphatase methylesterase-1 (PME-1) complex, which constitutively associates with the NK ?-subunit, is activated by SIK1 through phosphorylation of PME-1 and its dissociation from the complex. These observations illustrate the existence of a distinct intracellular signaling network, with SIK1 at its core, which is triggered by a monovalent cation (Na+) and links sodium permeability to its active transport.

Sjostrom, Mattias; Stenstrom, Karin; Eneling, Kristina; Zwiller, Jean; Katz, Adrian I.; Takemori, Hiroshi; Bertorello, Alejandro M.

2007-01-01

229

Intracellular calcium and its sodium-independent regulation in voltage-clamped snail neurones.  

PubMed Central

1. We have used both Ca(2+)-sensitive microelectrodes and fura-2 to measure the intracellular free calcium ion concentration ([Ca2+]i or its negative log, pCai) of snail neurones voltage clamped to -50 or -60 mV. Using Ca(2+)-sensitive microelectrodes, [Ca2+]i was found to be approximately 174 nM and pCai, 6.76 +/- 0.09 (mean +/- S.E.M.; n = 11); using fura-2, [Ca2+]i was approximately 40 nM and pCai, 7.44 +/- 0.06 (mean +/- S.E.M., n = 10). 2. Depolarizations (1-20 s) caused an increase in [Ca2+]i which was abolished by removal of extracellular Ca2+, indicating that the rise in [Ca2+]i was due to Ca2+ influx through voltage-activated Ca2+ channels. 3. Caffeine (10-20 mM) caused an increase in [Ca2+]i in the presence or absence of extracellular Ca2+. The effects of caffeine on [Ca2+]i could be prevented by ryanodine. 4. Thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+)-ATPase, caused a small increase in resting [Ca2+]i and slowed the rate of recovery from Ca2+ loads following 20 s depolarizations. 5. Neither replacement of extracellular sodium with N-methyl-D-glucamine (NMDG), nor loading the cells with intracellular sodium, had any effect on resting [Ca2+]i or the rate of recovery of [Ca2+]i following depolarizations. 6. The mitochondrial uncoupling agent carbonyl cyanide m-chlorophenylhydrazone (CCmP) caused a small gradual rise in resting [Ca2+]i. Removal of extracellular sodium during exposure to CCmP had no further effect on [Ca2+]i. 7. Intracellular orthovanadate caused an increase in resting [Ca2+]i and prevented the full recovery of [Ca2+]i following small Ca2+ loads, but removal of extracellular sodium did not cause a rise in [Ca2+]i. We conclude that there is no Na(+)-Ca2+ exchanger present in the cell body of these neurones and that [Ca2+]i is maintained by an ATP-dependent Ca2+ pump. Images Figure 1

Kennedy, H J; Thomas, R C

1995-01-01

230

Possible roles of exceptionally conserved residues around the selectivity filters of sodium and calcium channels.  

PubMed

In the absence of x-ray structures of sodium and calcium channels their homology models are used to rationalize experimental data and design new experiments. A challenge is to model the outer-pore region that folds differently from potassium channels. Here we report a new model of the outer-pore region of the NaV1.4 channel, which suggests roles of highly conserved residues around the selectivity filter. The model takes from our previous study (Tikhonov, D. B., and Zhorov, B. S. (2005) Biophys. J. 88, 184-197) the general disposition of the P-helices, selectivity filter residues, and the outer carboxylates, but proposes new intra- and inter-domain contacts that support structural stability of the outer pore. Glycine residues downstream from the selectivity filter are proposed to participate in knob-into-hole contacts with the P-helices and S6s. These contacts explain the adapted tetrodotoxin resistance of snakes that feed on toxic prey through valine substitution of isoleucine in the P-helix of repeat IV. Polar residues five positions upstream from the selectivity filter residues form H-bonds with the ascending-limb backbones. Exceptionally conserved tryptophans are engaged in inter-repeat H-bonds to form a ring whose ?-electrons would facilitate passage of ions from the outer carboxylates to the selectivity filter. The outer-pore model of CaV1.2 derived from the NaV1.4 model is also stabilized by the ring of exceptionally conservative tryptophans and H-bonds between the P-helices and ascending limbs. In this model, the exceptionally conserved aspartate downstream from the selectivity-filter glutamate in repeat II facilitates passage of calcium ions to the selectivity-filter ring through the tryptophan ring. Available experimental data are discussed in view of the models. PMID:21081490

Tikhonov, Denis B; Zhorov, Boris S

2010-11-16

231

Addition of sodium hyaluronate and the effect on performance of the injectable calcium phosphate cement.  

PubMed

An injectable calcium phosphate cement (CPC) with porous structure and excellent anti-washout ability was developed in the study. Citric acid and sodium bicarbonate were added into the CPC powder consisting of tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD) to form macro-pores, then different concentrations of sodium hyaluronate (NaHA) solution, as liquid phase, was added into the cement to investigate its effect on CPC's performance. The prepared CPCs were tested on workability (injectable time and setting time), mechanical strength, as well as anti-washout ability. The experimental results showed that addition of NaHA not only enhanced the anti-washout ability of the CPC dramatically but also improve its other properties. When NaHA concentration was 0.6 wt%, the injectable time elongated to 15.7 +/- 0.6 min, the initial and final setting times were respectively shorten to 18.3 +/- 1.2 and 58.7 +/- 2.1 min, and the compressive strength were increased to 18.78 +/- 1.83 MPa. On the other hand, Addition of NaHA showed little effect on porous structure of the CPC and enhanced its bioactivity obviously, which was confirmed by the apatite formation on its surface after immersion in simulated body fluid (SBF). In conclusion, as an in situ shaped injectable biomaterials, the CPC with appropriate addition of NaHA would notably improve its performance and might be used in minimal invasive surgery for bone repair or reconstruction. PMID:19291369

Kai, Dan; Li, Dongxiao; Zhu, Xiangdong; Zhang, Lei; Fan, Hongsong; Zhang, Xingdong

2009-03-17

232

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

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

F. A. Andersen

1998-01-01

233

A study of factors influencing hydration of sodium hyaluronate from compressibility and high-precision densimetric measurements.  

PubMed Central

A study of the factors influencing the hydration of the biopolymer hyaluronic acid was made by compressibility and density measurements. The factors investigated were the hydration changes on glycosidic bond formation, and also the influence of counterion type, solution ionic strength and temperature. The results indicate that, with this biopolymer, the hydration of the glucuronate residue is significantly more than that of the N-acetylglucosamine residue, and further that the biopolymer is less hydrated than the sum of its component monosaccharide residues. Change of the counterion salt form of this polyelectrolyte from univalent to bivalent counterion type (Na+ to Ca2+) leads to a small though significant increase in the total hydration sheath surrounding the polymer. An increase in the background ionic strength of the solvent leads to a quantifiable lowering of the hydration of the polymer at physiological ionic strength compared with its value in salt-free aqueous solution. A decrease in hydration with increase in temperature in the range 20-50 degrees C is the opposite of previous reports, and was observed when the polymer was dissolved both in pure water and in 0.15 M-NaCl.

Davies, A; Gormally, J; Wyn-Jones, E; Wedlock, D J; Phillips, G O

1983-01-01

234

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

PubMed

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

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

2009-01-14

235

Organization of Ryanodine Receptors, Transverse Tubules, and Sodium-Calcium Exchanger in Rat Myocytes  

PubMed Central

Abstract Confocal and total internal reflection fluorescence imaging was used to examine the distribution of caveolin-3, sodium-calcium exchange (NCX) and ryanodine receptors (RyRs) in rat ventricular myocytes. Transverse and longitudinal optical sectioning shows that NCX is distributed widely along the transverse and longitudinal tubular system (t-system). The NCX labeling consisted of both punctate and distributed components, which partially colocalize with RyRs (27%). Surface membrane labeling showed a similar pattern but the fraction of RyR clusters containing NCX label was decreased and no nonpunctate labeling was observed. Sixteen percent of RyRs were not colocalized with the t-system and 1.6% of RyRs were found on longitudinal elements of the t-system. The surface distribution of RyR labeling was not generally consistent with circular patches of RyRs. This suggests that previous estimates for the number of RyRs in a junction (based on circular close-packed arrays) need to be revised. The observed distribution of caveolin-3 labeling was consistent with its exclusion from RyR clusters. Distance maps for all colocalization pairs were calculated to give the distance between centroids of punctate labeling and edges for distributed components. The possible roles for punctate NCX labeling are discussed.

Jayasinghe, Isuru D.; Cannell, Mark B.; Soeller, Christian

2009-01-01

236

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

SciTech Connect

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.

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

2012-06-19

237

Light induced sodium dependent accumulation of calcium and potassium in the extracellular space of bee retina.  

PubMed

Intense illumination of long duration induced a large transient increase in extracellular calcium (delta[Ca2+]o) and potassium (delta[K+]o) during and after light in bee retina when measured with ion-selective microelectrodes. Whenever a large delta[Ca2+]o appeared, it was accompanied by a transient afterdepolarization (TA). Both the increase in [Ca2+]o, [K+]o and the TA were reduced or abolished when sodium was replaced by arginine, choline or lithium (Li+) ions. At 0-Na conditions a Na independent decrease in [Ca2+]o was observed during illumination only. A pronounced transient depolarization of the photoreceptor in the dark due to transient anoxia did not result in a significant change in [Ca2+]o. In some retinae the elevated level of [K+]o after light was absent, however a small Na-dependent TA was still observed. The above findings suggest that intense long illumination induces a large Ca2+ influx into the photoreceptors which is followed by Na-dependent Ca2+ efflux due to Na-Ca exchange. The light-induced afterdepolarization arises mainly from K+ accumulation in the extracellular space but partially from the electrogenicity of Na-Ca exchange. PMID:3750848

Minke, B; Tsacopoulos, M

1986-01-01

238

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

PubMed Central

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.

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

239

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

PubMed

Malignant glioma cells maintain an elevated intracellular pH (pH(i)) 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 pH(i) 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 [Ca(2+)](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 ([Ca(2+)](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 ?1?M, while dually inhibiting both NHE1 and NCX1.1 at ?20?M. DCB (1?M) was not cytotoxic to glioma cells, while DCB (20?M) further increased basal elevated levels of [Ca(2+)](i) in glioma cells that was followed by cell demise. Cariporide and SEA0400 are more selective 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

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

2010-10-13

240

Comparison of Soil-Test Extractants for Phosphorus, Potassium, Calcium, Magnesium, Sodium, Zinc, Copper, Manganese, and Iron in Louisiana Soils  

Microsoft Academic Search

Soils of different geographic regions affect efficiencies of individual soil-test extractants. Recent effort on nutrient-management programs across the United States has promoted establishment of conversion equations between different soil-test extractants for evaluating nutrients in similar soils. This study was carried out to compare soil-extractable phosphorus (P) by strong Bray (Bray 2), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na) by

Jim Jian Wang; Dustin L. Harrell; Rodney E. Henderson; Paul F. Bell

2004-01-01

241

EFFECTS OF CALCIUM SODIUM ETHYLENEDIAMINETETRA - ACETATE ON THE KINETICS OF DISTRIBUTION AND EXCRETION OF LEAD IN THE RAT  

Microsoft Academic Search

The effects of calcium sodium ethylenediaminetetra-acetate (CaNa2EDTA) on the kinetics of distribution and excretion of lead (210Pb) have been studied in rats. When the chelant was given intravenously, at 50 mg.\\/rat daily after a single intravenous injection of 100 ?g. lead\\/rat, it greatly increased the urinary excretion of lead but reduced the faecal excretion. The greatest effects occurred in the

N. Castellino; S. Aloj

1965-01-01

242

Sodium sulfate corrosion of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composites. Master's thesis  

Microsoft Academic Search

Hot corrosion effects of Sodium Sulfate (NaSO4) coated Calcium Aluminosilicate (CAS)\\/Silicon Carbide (SiC) reinforced glass-ceramic matrix composite were investigated using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-ray Diffraction (XRD). The samples provided by the Naval Air Warfare Center (NAWC) were unidirectional SiC\\/CAS as follows: (1) as received, (2) uncoated in air, (3) Na2SO4, coated in air

1994-01-01

243

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)

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+.

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

2010-03-01

244

Effect of biomedical organic compounds on the setting reaction of calcium phosphates.  

PubMed

In the present study, the effect of biomedical organic compounds (starch, sodium alginate, chitosan and gelatin) on the hydration of calcium phosphates was studied using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and XPS analysis. Amorphous calcium phosphate (ACP) was prepared by a mechanochemical route and mixed with biomedical organic compounds. A solidification reaction occurred between ACP and dicalcium phosphate dihydrate (DCPD); the hydration product was poorly crystallized hydroxyapatite (HA). During the setting reaction of ACP and DCPD, the presence of biomedical organic compounds had an effect on the hydration product: the bonding energies of the primary elements (Ca, P) in the hydration product (HA) were changed; also different hydration morphologies, self-setting properties, rheological properties and mechanical strength of the cement were obtained. This work will allow advances in the synthesis of bionic composite calcium phosphate cement (CPC). PMID:19811895

Yu, Tao; Ye, Jiandong; Gao, Chengying; Yu, Long; Wang, Yingjun

2009-09-19

245

Cytotoxicity of endodontic irrigants containing calcium hydroxide and sodium lauryl sulphate on fibroblasts derived from mouse L929 cell line.  

PubMed

The aim of this study was to evaluate the cytotoxicity of root canal irrigating solutions containing calcium hydroxide and sodium lauryl sulphate on fibroblasts derived from L929 cell line. Saturated calcium hydroxide aqueous solution (CH), sodium lauryl sulphate (SLS) and SLS associated with calcium hydroxide (HCT20) were diluted with sterile distilled water at 50%, 20%, 10% and 5% concentrations. Minimum essential medium (MEM) served as the control group. The cytotoxicity of the solutions was evaluated on L929 mouse fibroblast cell line, at 4 and 24 h of contact time by the 51Cr radiotracer method. Data were compared and statistical inferences were made with the chi-square test. In all analysis, significance level was set at 5%. CH and HCT20 showed toxicity at 50% concentration, while at concentrations lower than 50% these solutions showed cell tolerance. SLS was cytotoxic at all concentrations. In conclusion, the association of calcium hydroxide and SLS (HCT20) combines the beneficial properties of these solutions and was not harmful to the fibroblast cell line, seeming to be a suitable endodontic irrigating solution. PMID:19738943

Barbosa, Srgio Valmor; Barroso, Cristiane Maria Sodr; Ruiz, Patrcia Alvarez

2009-01-01

246

Calcium  

MedlinePLUS

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247

Dehydration\\/recrystallization mechanisms, energetics, and kinetics of hydrated calcium silicate minerals: an in situ TGA\\/DSC and synchrotron radiation SAXS\\/WAXS study  

Microsoft Academic Search

The dehydration and recrystallization of the natural hydrated calcium silicates xonotlite [Ca6Si6O17(OH)2], 11 anomalous tobermorite [Ca5Si6O16(OH)24H2O], and hillebrandite [Ca2SiO3(OH)2] were studied in situ by dynamic heating (5C min?1) differential scanning calorimetry\\/thermogravimetric analysis (TGA\\/DSC) and synchrotron small- and wide-angle X-ray scattering (SAXS\\/WAXS). All have structures based on silicate chains with a repeat unit of three tetrahedra (dreierketten). Room-T infrared data for

S Shaw; C. M. B Henderson; B. U Komanschek

2000-01-01

248

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

Microsoft Academic Search

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

Josephine Lutz

249

Prophylactic and therapeutic properties of a sodium citrate preparation in the management of calcium oxalate urolithiasis: randomized, placebo-controlled trial  

Microsoft Academic Search

The purpose of this study was to investigate the prophylactic and therapeutic effects of a hitherto untested preparation containing sodium citrate in the management of calcium oxalate urolithiasis. In this study, a host of calcium oxalate kidney stone risk factors was investigated using a randomised, placebo controlled, within-patient clinical trial. The trial involved four groups of subjects: healthy male controls,

Shameez Allie-Hamdulay; Allen L. Rodgers

2005-01-01

250

The effect of Portuguese Man-of-war ( Physalia physalis) venom on calcium, sodium and potassium fluxes of cultured embryonic chick heart cells  

Microsoft Academic Search

Portuguese Man-of-war venom markedly increases calcium (45Ca2+) influx into primary, cultured, embryonic chick heart cells. This action is dose-dependent, but is unaffected by organic calcium blockers (diltiazem, verapamil, nifedipine, nimodipine and mibefradil). On the other hand, certain trivalent (La3+, Gd3+) and divalent (Zn2+, Ni2+, Cu2+, Mn2+) metals inhibit venom-induced calcium influx. Sodium (22Na+) influx into chick heart cells is also

Lincoln Edwards; Eva Luo; Raymond Hall; Ramon R Gonzalez; David A Hessinger

2000-01-01

251

Heparin identification test and purity test for OSCS in heparin sodium and heparin calcium by weak anion-exchange high-performance liquid chromatography  

Microsoft Academic Search

Heparin sodium and heparin calcium, which are widely used as anti-coagulants, are known to potentially contain the natural impurity dermatan sulfate (DS). Recently serious adverse events occurred in patients receiving heparin sodium in the US, and a contaminant oversulfated chondroitin sulfate (OSCS) was found to be a cause of the events. To ensure the quality and safety of pharmaceutical heparins,

Noritaka Hashii; Nana Kawasaki; Satsuki Itoh; Yan Qin; Naho Fujita; Toshiaki Hattori; Kazuyoshi Miyata; Aya Bando; Yuko Sekimoto; Takeshi Hama; Masaki Kashimura; Masashi Tatsumi; Kazunori Mabuchi; Hiroshi Namekawa; Toru Sakai; Mio Hirose; Sei Dobashi; Hirotoshi Shimahashi; Sadatoshi Koyama; Susanne Odgaard Herr; Kenzo Kawai; Hikaru Yoden; Teruhide Yamaguchi

2010-01-01

252

In vitro enamel remineralization by low-fluoride toothpaste with calcium citrate and sodium trimetaphosphate.  

PubMed

The objective of this study was to evaluate in vitro the effect of a low fluoride toothpaste (450 gF/g, NaF) combined with calcium citrate (Cacit) and sodium trimetaphosphate (TMP) on enamel remineralization. Bovine enamel blocks had the enamel surface polished sequentially to determine the surface hardness. After production of artificial carious lesions, the blocks selected by their surface hardness were submitted to remineralization pH cycling and daily treatment with dentifrice suspensions (diluted in deionized water or artificial saliva): placebo, 275, 450, 550 and 1,100 gF/g and commercial dentifrice (positive control, 1,100 gF/g). Finally, the surface and cross-section hardness was determined for calculating the change of surface hardness (%SH) and mineral content (%?Z). Fluoride in enamel was also determined. The data from %SH, %?Z and fluoride were subjected to two-way analysis of variance followed by Student-Newman-Keuls's test (p<0.05). The mineral gain (%SH and %?Z) was higher for toothpastes diluted in saliva (p<0.05), except for the 450 gF/g dentifrice with Cacit/TMP (p>0.05). The 450 Cacit/TMP toothpaste and the positive control showed similar results (p>0.05) when diluted in water. A dose-response was observed between fluoride concentration in toothpastes and fluoride present in enamel, regardless of dilution. It was concluded that it is possible to enhance the remineralization capacity of low F concentration toothpaste by of organic (Cacit) and inorganic (TMP) compounds with affinity to hydroxyapatite. PMID:23969915

Hirata, Edo; Danelon, Marcelle; Freire, Isabelle Rodrigues; Delbem, Alberto Carlos Botazzo

253

Seeing the forest through the trees: towards a unified view on physiological calcium regulation of voltage-gated sodium channels.  

PubMed

Voltage-gated sodium channels (Na(V)s) underlie the upstroke of the action potential in the excitable tissues of nerve and muscle. After opening, Na(V)s rapidly undergo inactivation, a crucial process through which sodium conductance is negatively regulated. Disruption of inactivation by inherited mutations is an established cause of lethal cardiac arrhythmia, epilepsy, or painful syndromes. Intracellular calcium ions (Ca(2+)) modulate sodium channel inactivation, and multiple players have been suggested in this process, including the cytoplasmic Na(V) C-terminal region including two EF-hands and an IQ motif, the Na(V) domain III-IV linker, and calmodulin. Calmodulin can bind to the IQ domain in both Ca(2+)-bound and Ca(2+)-free conditions, but only to the DIII-IV linker in a Ca(2+)-loaded state. The mechanism of Ca(2+) regulation, and its composite effect(s) on channel gating, has been shrouded in much controversy owing to numerous apparent experimental inconsistencies. Herein, we attempt to summarize these disparate data and propose a novel, to our knowledge, physiological mechanism whereby calcium ions promote sodium current facilitation due to Ca(2+) memory at high-action-potential frequencies where Ca(2+) levels may accumulate. The available data suggest that this phenomenon may be disrupted in diseases where cytoplasmic calcium ion levels are chronically high and where targeted phosphorylation may decouple the Ca(2+) regulatory machinery. Many Na(V) disease mutations associated with electrical dysfunction are located in the Ca(2+)-sensing machinery and misregulation of Ca(2+)-dependent channel modulation is likely to contribute to disease phenotypes. PMID:23283222

Van Petegem, Filip; Lobo, Paolo A; Ahern, Christopher A

2012-12-01

254

Calcium Block of Sodium Current in a Model Calcium Channel: Cylindrical Atomistic Pore with Glutamate Side Chains  

Microsoft Academic Search

Biological calcium channels are known to have permeation selectivity governed by the acidic groups on four conserved glutamate side chains, one each from the P regions of the four homologous domains. The binding selectivity of this filter region is revealed experimentally by the fact that at low external [Ca] (1??M), current carried by Na ions is blocked completely. In our

Yan Yang; Douglas Henderson; David D. Busath

2004-01-01

255

Combined effects of potassium lactate and calcium ascorbate as sodium chloride substitutes on the physicochemical and sensory characteristics of low-sodium frankfurter sausage.  

PubMed

The purpose of this study was to evaluate the combined effects of sodium chloride (NaCl) substitutes, including potassium lactate (K-lactate) and calcium ascorbate (Ca-ascorbate), on the physicochemical and sensory characteristics of low-sodium frankfurter sausage (1.2% content of NaCl). Sausages produced with 40% substitution of NaCl with combined K-lactate and Ca-ascorbate showed a higher value of lightness (P<0.001) than sausages containing 2.0% content of NaCl (control). However, the sensory panels were unable to distinguish a difference in color intensity between the control and treatment groups. Frankfurter sausages produced with 30% K-lactate and 10% Ca-ascorbate exhibited similar water-holding capacity, textural properties, and organoleptic characteristics (P>0.05) when compared to control sausages. Thus, the use of these salt mixtures is a good way to reduce the NaCl content in meat products while maintaining the quality of meat products. These results may be useful in developing low-sodium meat products. PMID:23896133

Choi, Y M; Jung, K C; Jo, H M; Nam, K W; Choe, J H; Rhee, M S; Kim, B C

2013-06-22

256

Microstructure and Physical Properties of Sulfate Hydrate/Ice Eutectic Aggregates in the Binary System Sodium-Sulfate/Water at Planetary Conditions  

NASA Astrophysics Data System (ADS)

Reflectance spectra data from Mars Odyssey, Galileo and potentially from Cassini suggest the presence of hydrated salts on numerous satellites in environments such as evaporate beds or combined with water ice. Improved mission data on these occurrences indicate that grain structures and properties of such materials merit a closer look using laboratory methods. Here we report the synthesis of a two-phase aggregate of sodium sulfate hydrate and water ice made by eutectic solidification from solution, characterization of its microstructure using cryogenic SEM, and comparison of its physical properties to those of its end-member components. Samples are crystallized from solution using a precision cryobath and seeded growth. The reaction is a "simple" one meaning that there is no solid solution formation in either of the two solid phases. The eutectic composition we studied for the sodium sulfate hydrate is 4wt% Na2SO4, which corresponds to about .06 volume fraction of Na2SO4?10H2O, mirabilite, and .94 ice I. The eutectic microstructure observed with this volume fraction, which is termed "broken lamellar", consists of fairly uniform blade-like mirabilite grains arranged in roughly parallel columns within a water ice matrix. The blades and matrix material form a lamella that alternates with lamellae of pure ice. Energy dispersive spectroscopy of these eutectic mixtures confirms the presence of the two crystalline phases. Also, we find that lamellar spacing decreases with increasing growth rate. Constant-strain-rate tests in compression are carried out in the cryogenic gas deformation apparatus at LLNL in a pressure-temperature range appropriate to the icy satellites. We report the rheology of the two-phase aggregate and compare it to the strength properties of pure water ice and pure mirabilite. With the aid of numerous studies on similar structures in the literature on metals, we analyze the deformation mechanics from the perspective of defect and crack propagation between the two phases in the eutectic structure. This ongoing investigation is the first of several planned experimental studies of sulfate-hydrate binaries with ice I that are likely to be important in the icy satellites.

McCarthy, C. M.; Kirby, S.; Durham, W.; Stern, L.

2004-12-01

257

Glass powder blended cement hydration modelling  

NASA Astrophysics Data System (ADS)

The use of waste materials in construction is among the most attractive options to consume these materials without affecting the environment. Glass is among these types of potential waste materials. In this research, waste glass in powder form, i.e. glass powder (GP) is examined for potential use in enhancing the characteristics of concrete on the basis that it is a pozzolanic material. The experimental and the theoretical components of the work are carried out primarily to prove that glass powder belongs to the "family" of the pozzolanic materials. The chemical and physical properties of the hydrated activated glass powder and the hydrated glass powder cement on the microstructure level have been studied experimentally and theoretically. The work presented in this thesis consists of two main phases. The first phase contains experimental investigations of the reaction of glass powder with calcium hydroxide (CH) and water. In addition, it includes experiments that are aimed at determining the consumption of water and CH with time. The reactivity, degree of hydration, and nature of the pore solution of the glass powder-blended cement pastes and the effect of adding different ratios of glass powder on cement hydration is also investigated. The experiments proved that glass powder has a pozzolanic effect on cement hydration; hence it enhances the chemical and physical properties of cement paste. Based on the experimental test results, it is recommended to use a glass powder-to-cement ratio (GP/C) of 10% as an optimum ratio to achieve the best hydration and best properties of the paste. Two different chemical formulas for the produced GP C-S-H gel due to the pure GP and GP-CH pozzolanic reaction hydration are proposed. For the pure GP hydration, the produced GP C-S-H gel has a calcium-to-silica ratio (C/S) of 0.164, water-to-silica ratio (H/S) of 1.3 and sodium/silica ratio (N/S) of 0.18. However, for the GP-CH hydration, the produced GP C-S-H gel has a C/S ratio of 1.17, H/S ratio of 2.5 and N/S ratio of 0.18. In the second phase of this research, theoretical models are built using a modified version of an existing cement hydration modelling code, "CEMHYD3D", to simulate the chemical reaction of the activated glass powder hydration and glass powder in cement. The modified model, which is referred to as the "MOD-model" is further used to predict the types, compositions and quantities of reaction products. Furthermore, the glass powder hydration data, which is obtained experimentally, is incorporated into the MOD-model to determine the effect of adding glass powder to the paste on the process of cement hydration and resulting paste properties. Comparisons between theoretical and experimental results are made to evaluate the developed models. The MOD-model predictions have been validated using the experimental results, and were further used to investigate various properties of the hydrated glass powder cement paste. These properties include, for example, CH content of the paste, porosity, hydration degree of the glass powder and conventional C-S-H and GP CS-H contents. The results show that the MOD-model is capable of accurately simulating the hydration process of glass powder-blended cement paste and can be used to predict various properties of the hydrating paste.

Saeed, Huda

258

Regional genomic regulation of cardiac sodium-calcium exchanger by oestrogen  

PubMed Central

Female rabbit hearts are more susceptible to torsade de pointes (TdP) in acquired long QT type 2 than males, in-part due to higher L-type Ca2+ current (ICa,L) at the base of the heart. In principle, higher Ca2+ influx via ICa,L should be balanced by higher efflux, perhaps mediated by parallel sex differences of sodiumcalcium exchange (NCX) current (INCX). We now show that NCX1, like Cav1.2?, is greater at the base of female than male left ventricular epicardium and greater at the base than at the apex in both sexes. In voltage-clamp studies, inward (0, +20 mV, P < 0.04) and outward (?80, ?60, ?40, ?20 mV, P < 0.01) INCX densities were significantly higher (1.52 fold) in female base compared to apex and male (base and apex) myocytes. Myocytes were incubated 17?-oestradiol (E2 = 1 nm) and INCX was measured on days 0, 1, 2 and 3. Inward and outward INCX decreased over 2 days in female base myocytes becoming similar to INCX at the apex. E2 incubation (24 h) increased NCX1 (50%) and INCX (?3-fold at 60 mV) in female base but not endocardium, apex or in male base myocytes. INCX upregulation by E2 was blunted by an oestrogen receptor (ER) antagonist (fulvestrant, 1 ?m), and inhibition of transcription (actinomycin D, 5 ?g ml?1) or translation (cycloheximide, 20 ?g ml?1). Dofetilide (an IKr blocker) induced early afterdepolarizations (EADs) in female base myocytes cultured for 1 day if incubated with E2, but not without E2 or with E2+KB-R4973 (an INCX inhibitor), E2+fulvestrant or E2 with apex myocytes. Thus, E2 upregulates NCX1 by a genomic mechanism mediated by ERs, and de novo mRNA and protein biosynthesis, in a sex- and region-dependent manner which contributes to the enhanced propensity to EADs and TdP in female hearts.

Chen, Guojun; Yang, Xiaoyan; Alber, Sean; Shusterman, Vladimir; Salama, Guy

2011-01-01

259

Calcium  

MedlinePLUS

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260

Occurrence of methane hydrate in saturated and unsaturated solutions of sodium chloride and water in dependence of temperature and pressure  

Microsoft Academic Search

Experimental results of the formation of methane hydrate in dependence of temperature and pressure in unsaturated solutions of NaCl in water will be presented in a temperature range from 261.85 to 285.98 K and pressure up to 11.0 MPa. Furthermore the four-phase equilibrium NaCl X 2HO \\/SUB s\\/ -CH X nHO \\/SUB s\\/ -L-G has been calculated from the experimental

J. L. de Roo; G. A. M. Diepen; R. N. Lichtenthaler; C. J. Peters

1983-01-01

261

Interactions of Organic Additives with Ionic Crystal Hydrates  

NASA Astrophysics Data System (ADS)

The interactions of two groups of hydrated model crystals, calcium hydrogenphosphate dihydrate (DCPD) vs. octacalcium phosphate (OCP) and calcium oxalate monohydrate (COM) vs. calcium oxalate dihydrate (COD) with different organic additives are considered. DCPD precipitates as platelet-like crystals with the dominant faces shielded by hydrated layers and charged lateral faces. In the second system COM has charged surfaces, while all faces of COD are covered with layers containing water molecules. The organic molecules tested include negatively charged, flexible and rigid small and macromolecules (glutamic and aspartic acid, citrate, hexaammonium polyphosphate, phytate and polyaspartate) and anionic surfactants (sodium dodecyl sulphate, SDS, sodium diisooctyl sulfosuccinate, AOT, sodium cholate NaC and disodium oleoamido PEG-2 sulfosuccinate, PEG). Two types of effects have been demonstrated: (1) Effect on crystal growth morphology: Flexible organic molecules with high charge density and anionic surfactants affected the growth morphology of DCPD and COM by selectively interacting with the charged lateral faces while rigid molecules (phytate, polyaspartate) specifically recognized the dominant (010) face of DCPD due to structural and stereochemical compatibility. (2) Effect on phase composition: Anionic surfactants at concentrations above the cmc promoted growth of OCP and COD respectively by selectively adsorbing at, and inhibiting growth oif nuclei of DCPD and/or COM, which were dominant in the respective control systems. The effect was especially pronounced in the calcium oxalate precipitation system, where in some cases complete reversal of the phase composition occurred. The important role of the hydrated layer, as part of the structure of the investigated crystal hydrates, in the above crystal additive interactions is discussed.

Fredi-Milhofer, H.; Sikiri?, M.; Tunik, L.; Filipovi?-Vincekovi?, N.; Garti, N.

262

Effects of Estradiol and IGF-1 on the Sodium Calcium Exchanger in Rat Cultured Cortical Neurons  

Microsoft Academic Search

The Na+\\/Ca2+ exchanger (NCX) is an important bidirectional transporter of calcium in neurons and has been shown to be involved in neuroprotection.\\u000a Calcium can activate a number of cascades that can result in apoptosis and cell death, and NCX is a key factor in regulating\\u000a the cytoplasmic concentration of this ion. 17-?-estradiol and insulin-like growth factor 1 (IGF-1) are known

Julio C. Snchez; Diego F. Lpez-Zapata; Liliana Francis; Lina De Los Reyes

2011-01-01

263

Antiplatelet and calcium inhibitory properties of eugenol and sodium eugenol acetate  

Microsoft Academic Search

1.1. Eugenol (3-methoxy-4-hydroxy-propenylbenzene) or sodium eugenol acetate (4-0-acetic acid sodium-3-methoxy-l-propenylbenzene) (0.25, 0.5, 1 mM) concentration-dependently inhibited arachidonic acid (AA)., collagen-, epinephrine- and ADP-induced platelet aggregation.2.2. Eugenol or sodium eugenol acetate inhibited collagen-induced aggregation of washed rabbit platelets synergistically with creatine phosphatelcreatine phosphokinase (CP\\/CPK, 5 mM\\/10 U\\/ml) or p-bromophenacyl bromide (p-BPB, 10 ?M), and they also potentiated the inhibitory action of

Sheue-Jiun Chen; Ming-Hsin Wang; Ing-Jun Chen

1996-01-01

264

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+ ...

265

The effect of calcium and sodium lactates on growth from spores of Bacillus cereus and Clostridium perfringens in a sous-vide beef goulash under temperature abuse  

Microsoft Academic Search

The effect of calcium and sodium lactates on growth from spores of Bacillus cereus and Clostridium perfringens at three different concentrations (0, 1.5 and 3% w\\/w) and at different temperatures (10, 15 and 20C for B. cereus and 15, 20 and 25C for C. perfringens) was investigated, using beef goulash as a model system for pasteurised vacuum-packaged convenience foods. Calcium

Necla Aran

2001-01-01

266

Why and how to implement sodium, potassium, calcium, and magnesium changes in food items and diets?  

Microsoft Academic Search

The present average sodium intakes, approximately 30004500 mg\\/day in various industrialised populations, are very high, that is, 23-fold in comparison with the current Dietary Reference Intake (DRI) of 1500 mg. The sodium intakes markedly exceed even the level of 2500 mg, which has been recently given as the maximum level of daily intake that is likely to pose no risk

H Karppanen; P Karppanen; E Mervaala

2005-01-01

267

Final report of the safety assessment of L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate as used in cosmetics.  

PubMed

L-Ascorbic Acid, Calcium Ascorbate, Magnesium Ascorbate, Magnesium Ascorbyl Phosphate, Sodium Ascorbate, and Sodium Ascorbyl Phosphate function in cosmetic formulations primarily as antioxidants. Ascorbic Acid is commonly called Vitamin C. Ascorbic Acid is used as an antioxidant and pH adjuster in a large variety of cosmetic formulations, over 3/4 of which were hair dyes and colors at concentrations between 0.3% and 0.6%. For other uses, the reported concentrations were either very low (<0.01%) or in the 5% to 10% range. Calcium Ascorbate and Magnesium Ascorbate are described as antioxidants and skin conditioning agents--miscellaneous for use in cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted as a nitrosation inhibitor in several food and cosmetic product studies. No compound-related clinical signs or gross or microscopic pathological effects were observed in either mice, rats, or guinea pigs in short-term studies. Male guinea pigs fed a control basal diet and given up to 250 mg Ascorbic Acid orally for 20 weeks had similar hemoglobin, blood glucose, serum iron, liver iron, and liver glycogen levels compared to control values. Male and female F344/N rats and B6C3F(1) mice were fed diets containing up to 100,000 ppm Ascorbic Acid for 13 weeks with little toxicity. Chronic Ascorbic Acid feeding studies showed toxic effects at dosages above 25 mg/kg body weight (bw) in rats and guinea pigs. Groups of male and female rats given daily doses up to 2000 mg/kg bw Ascorbic Acid for 2 years had no macro- or microscopically detectable toxic lesions. Mice given Ascorbic Acid subcutaneous and intravenous daily doses (500 to 1000 mg/kg bw) for 7 days had no changes in appetite, weight gain, and general behavior; and histological examination of various organs showed no changes. Ascorbic Acid was a photoprotectant when applied to mice and pig skin before exposure to ultraviolet (UV) radiation. The inhibition of UV-induced suppression of contact hypersensitivity was also noted. Magnesium Ascorbyl Phosphate administration immediately after exposure in hairless mice significantly delayed skin tumor formation and hyperplasia induced by chronic exposure to UV radiation. Pregnant mice and rats were given daily oral doses of Ascorbic Acid up to 1000 mg/kg bw with no indications of adult-toxic, teratogenic, or fetotoxic effects. Ascorbic Acid and Sodium Ascorbate were not genotoxic in several bacterial and mammalian test systems, consistent with the antioxidant properties of these chemicals. In the presence of certain enzyme systems or metal ions, evidence of genotoxicity was seen. The National Toxicology Program (NTP) conducted a 2-year oral carcinogenesis bioassay of Ascorbic Acid (25,000 and 50,000 ppm) in F344/N ra

Elmore, Amy R

2005-01-01

268

Relationship of urinary sodium\\/potassium excretion and calcium intake to blood pressure and prevalence of hypertension among older Chinese vegetarians  

Microsoft Academic Search

Objective: To examine the associations of dietary sodium and potassium, as reflected by the urinary sodium\\/potassium excretion, and calcium intake with blood pressure and the prevalence of hypertension among older Chinese vegetarians in Hong Kong.Design: Cross-sectional study.Setting: Research clinic in a teaching hospital in Hong Kong.Subjects: A total of 111 ambulatory vegetarians over the age of 55 were recruited from

T C Y Kwok; T Y K Chan; J Woo

2003-01-01

269

X-ray crystal structure and vibrational spectra of hydrazides and their metal complexes. Part I. Catena-poly[di-?-aqua-(?-maleic hydrazidato-O)sodium] hydrate  

NASA Astrophysics Data System (ADS)

The catena-poly[di-?-aqua-(?-maleic hydrazidato-O)sodium] hydrate, [Na(MH) (H2O)2]nH2O is examined using single crystal X-ray diffraction analysis. The crystals are monoclinic, space group C2/c, with a = 14.321(4), b = 16.114(5), c = 6.547(1) , ? = 104.11(2) and Z = 4. In title complex, each sodium ion is coordinated by two oxygen atoms of two water molecules, one oxygen atom of the maleic hydrazidato, two oxygen atoms of two water molecules from an adjacent [Na(MH)(H2O)2] unit and one oxygen atom of the maleic hydrazidato from an adjacent [Na(MH)(H2O)2] unit too. It is interesting that the sodium ion is not bonded by O-deprotonated oxygen atom but by carbonyl oxygen atom of maleic hydrazidato. The infrared and Raman spectra for maleic hydrazide (MH), its deuterated derivative (MD) and [Na(MH)(H2O)2]nH2O are reported. The theoretical wavenumbers, infrared intensities and Raman scattering activities have been calculated using density functional (B3LYP) method with the 6-311++G(d,p) for MH and MD and 6-311++G(d,p)/LanL2DZ for [Na(MH)(H2O)2]nH2O basis sets. The calculated potential energy distribution has proved to be of great help in assigning the infrared and Raman spectra maleic hydrazide, its deuterated derivative and [Na(MH)(H2O)2]nH2O. The isotope replacements were very helpful in correlation of observed bands and of the theoretically calculated normal vibrations. The results from natural bond orbital (NBO) analyses for keto-hydroxy, diketo and dihydroxy forms of MH as well as for the theoretical model of [Na(MH)(H2O)2]nH2O are compared.

Morzyk-Ociepa, Barbara

2007-05-01

270

Steady-state and dynamic properties of cardiac sodium-calcium exchange. Ion and voltage dependencies of the transport cycle  

PubMed Central

Ion and voltage dependencies of sodium-calcium exchange current were studied in giant membrane patches from guinea pig ventricular cells after deregulation of the exchanger with chymotrypsin. (a) Under zero- trans conditions, the half-maximum concentration (Kh) of cytoplasmic calcium (Cai) for activation of the isolated inward exchange current decreased as the extracellular sodium (Nao) concentration was decreased. The Kh of cytoplasmic sodium (Nai) for activation of the isolated outward exchange current decreased as the extracellular calcium (Cao) concentration was decreased. (b) The current-voltage (I- V) relation of the outward exchange current with saturating concentrations of Nai and Cao had a shallow slope (twofold change in approximately 100 mV) and a slight saturation tendency at very positive potentials. The outward current gained in steepness as the Nai concentration was decreased, such that the Kh for Nai decreased with depolarization. The decrease of Kh for Nai with depolarization was well described by a Boltzmann equation (e alpha.Em/26.6) with a slope (alpha) of -0.06. (c) Voltage dependence of the outward current was lost as the Cao concentration was decreased, and the Kh for Cao increased upon depolarization with a Boltzmann slope of 0.26. (d) The I- V relation of the inward exchange current, under zero-trans conditions, was also almost linear (twofold change in approximately 100 mV) and showed some saturation tendency with hyperpolarization as the Cai concentration was decreased. The Kh for Cai decreased with depolarization (Boltzmann slope, -0.10). Voltage dependence of the inward current was decreased in the presence of a high (300 mM) Nao concentration. (e) In the presence of both Na and Ca on both membrane sides, the I-V relations with saturating Nai show sigmoidal shape and clear saturation at positive potentials. Measured reversal potentials were close to the equilibrium potential expected for a 3 Na to 1 Ca exchange. (f) Nai and Cai interacted competitively with respect to the outward current, but in a mixed competitive-noncompetitive fashion with respect to the inward current. (g) Cai inhibited the outward exchange current in a voltage-dependent manner. The half-effective concentration for inhibition (Ki) by Cai increased upon depolarization with a Boltzmann slope of 0.32 in 25 mM Nai and 0.20 in 100 mM Nai. (h) Nai also inhibited the inward exchange current voltage dependently. The Ki decreased upon depolarization (Boltzmann slope, -0.11 at 3 microM Cai and -0.10 at 1.08 mM Cai).(ABSTRACT TRUNCATED AT 400 WORDS)

1992-01-01

271

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

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.

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

272

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

Microsoft Academic Search

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

S. E Doty; R. C Seagrave

2000-01-01

273

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

Microsoft Academic Search

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

S. E. Doty; R. C. Seagrave

1999-01-01

274

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

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

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

2008-01-01

275

Effect of calcium hydroxide, carbonate and sodium bicarbonate on water quality and zootechnical performance of shrimp Litopenaeus vannamei reared in bio-flocs technology (BFT) systems  

Microsoft Academic Search

Litopenaeus vannamei (the Pacific white shrimp) is the most commonly reared species in super-intensive biofloc technology (BFT) without water renewal. In BFT, the pH may decrease due to the reduction of alkalinity and the increase of dissolved carbon dioxide. This study evaluated the effects of calcium hydroxide, sodium carbonate and bicarbonate in maintaining water quality during the cultivation of L.

Plnio S. Furtado; Lus H. Poersch; Wilson Wasielesky

2011-01-01

276

Insight into elastic behavior of calcium silicate hydrated oxide (CSH) under pressure and composition effect  

Microsoft Academic Search

The present work relates to the study of structural and elastic properties of Tobermorite 11 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

Ali Zaoui

277

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

PubMed

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

Chibowski, Emil; Szczes, Aleksandra; Holysz, Lucyna

2005-08-30

278

Sodium sulfate corrosion of silicon carbide fiber-reinforced calcium aluminosilicate glass-ceramic matrix composites. Master's thesis  

SciTech Connect

Hot corrosion effects of Sodium Sulfate (NaSO4) coated Calcium Aluminosilicate (CAS)/Silicon Carbide (SiC) reinforced glass-ceramic matrix composite were investigated using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Analysis (EDX) and X-ray Diffraction (XRD). The samples provided by the Naval Air Warfare Center (NAWC) were unidirectional SiC/CAS as follows: (1) as received, (2) uncoated in air, (3) Na2SO4, coated in air and (4) Na2SO4 coated in argon. A heat treatment was conducted at 900 deg C for 100 hours. Experimental observations indicated that the Na2S04 coating in an oxidising environment had severely corroded the silicon fiber resulting in a silica rich, Nepheline, Wollastonite, Rankinite, Albite and glassy phases. In the argon atmosphere fiber degradation was present although less severe than in the oxygen environment. Similar phases of silica rich, Nepheline, Albite, Rankinite, Mullite, Pseudo-Wollastonite and a glassy region were present. Minimal fiber and matrix degradation was observed in the uncoated sample beat treated in air. Calcium aluminosilicate, SiC Fiber reinforced composites.

Newton, P.J.

1994-03-01

279

The effect of Portuguese Man-of-war (Physalia physalis) venom on calcium, sodium and potassium fluxes of cultured embryonic chick heart cells.  

PubMed

Portuguese Man-of-war venom markedly increases calcium (45Ca2+) influx into primary, cultured, embryonic chick heart cells. This action is dose-dependent, but is unaffected by organic calcium blockers (diltiazem, verapamil, nifedipine, nimodipine and mibefradil). On the other hand, certain trivalent (La3+, Gd3+) and divalent (Zn2+, Ni2+, Cu2+, Mn2+) metals inhibit venom-induced calcium influx. Sodium (22Na+) influx into chick heart cells is also significantly increased by Man-of-war venom. Flecainide does not block venom-induced sodium influx. The efflux of the potassium analogue, 86Rb+, from heart cells is also significantly increased by the venom. The venom, however, has little or no effect on rubidium (86Rb+) or 2-deoxy-D-[2-3H] glucose influx. PMID:10669022

Edwards, L; Luo, E; Hall, R; Gonzalez, R R; Hessinger, D A

2000-03-01

280

Effects of verapamil, sodium nitroprusside and calcium deprivation on the phenylephrine-induced contraction of smooth muscle strips from the reticular groove of adult cattle.  

PubMed

The effects of verapamil, sodium nitroprusside and calcium deprivation on the smooth muscle strips from the floor of the reticular groove of adult cattle were studied. The mechanical activity of the muscle strip was recorded isometrically. Contraction was induced with phenylephrine (10(-6) mol/l) in Tyrode solution. Verapamil (10(-6) mol/l) produced a high inhibition of the response, phasic and tonic (P < 0.05). Sodium nitroprusside (10(-6) mol/l) reduced mainly the phasic contraction (P < 0.05). Deprivation of Ca2+ from extracellular medium produced a high inhibition of the tonic phase. This study indicates that the action of verapamil on the reticular groove smooth muscle may be partially related to blockade of calcium entry through voltage-dependent channels, opened during phenylephrine stimulation. However, the nitroprusside action could be attributed to effect on the extrusion of calcium. PMID:9697425

San Andrs, M D; Encinas, T; Gonzlez, F; de Vicente, M L; San Andrs, M I; Rodrguez, C

1998-05-01

281

The epithelial sodium/proton exchanger, NHE3, is necessary for renal and intestinal calcium (re)absorption  

PubMed Central

Passive paracellular proximal tubular (PT) and intestinal calcium (Ca2+) fluxes have been linked to active sodium (re)absorption. Although the epithelial sodium/proton exchanger, NHE3, mediates apical sodium entry at both these sites, its role in Ca2+ homeostasis remains unclear. We, therefore, set out to determine whether NHE3 is necessary for Ca2+ (re)absorption from these epithelia by comparing Ca2+ handling between wild-type and NHE3?/? mice. Serum Ca2+ and plasma parathyroid hormone levels were not different between groups. However, NHE3?/? mice had increased serum 1,25-dihydroxyvitamin D3. The fractional excretion of Ca2+ was also elevated in NHE3?/? mice. Paracellular Ca2+ flux across confluent monolayers of a PT cell culture model was increased by an osmotic gradient equivalent to that generated by NHE3 across the PT in vivo and by overexpression of NHE3. 45Ca2+ uptake after oral gavage and flux studies in Ussing chambers across duodenum of wild-type and NHE3?/? mice confirmed decreased Ca2+ absorption in NHE3?/? mice compared with wild-type mice. Consistent with this, intestinal calbindin-D9K, claudin-2, and claudin-15 mRNA expression was decreased. Microcomputed tomography analysis revealed a perturbation in bone mineralization. NHE3?/? mice had both decreased cortical bone mineral density and trabecular bone mass. Our results demonstrate significant alterations of Ca2+ homeostasis in NHE3?/? mice and provide a molecular link between Na+ and Ca2+ (re)absorption.

Pan, Wanling; Borovac, Jelena; Spicer, Zachary; Hoenderop, Joost G.; Bindels, Rene J.; Shull, Gary E.; Doschak, Michael R.; Cordat, Emmanuelle

2012-01-01

282

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

Microsoft Academic Search

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

M. G. Kurmashov

1982-01-01

283

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

Microsoft Academic Search

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

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

2000-01-01

284

Effects of poly (sodium 4-styrene-sulfonate) on morphology of calcium carbonate particles  

Microsoft Academic Search

In this paper, a systematic examination of the influence of various experimental parameters on the morphology and size of CaCO3 particles at room temperature in the presence of poly (sodium 4-styrene-sulfonate) (PSSS) is presented. The as-prepared products were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry-thermogravimetry (DSC-TG) and X-ray diffraction (XRD). The results show that

M. Lei; W. H. Tang; L. Z. Cao; P. G. Li; J. G. Yu

2006-01-01

285

The role of hydrated divalent metal ions in the bridging of two anionic groups. An ab initio quantum chemical and molecular mechanics study of dimethyl phosphate and formate bridged by calcium and magnesium ions.  

PubMed

Ab initio quantum chemical (Gaussian82) and molecular mechanics (AMBER2.0) computational techniques are employed to investigate the interaction of two anions (formate an dimethylphosphate) and a central divalent metal cation (magnesium or calcium). These systems are models for the essential GDP binding unit of the G-proteins (e.g., EF-Tu or the ras oncogene proteins) and for protein/phospholipid interactions, both of which are mediated by divalent metal cations. Various levels of hydration are utilized to examine coordination of differences between magnesium and calcium ions. Two different orientations of formate and dimethyl phosphate in direct ion contact with a magnesium ion and two waters of hydration were energy minimized with both quantum and molecular mechanics techniques. The structures and energy differences between the two orientations determined by either of the computational techniques are similar. Magnesium ion has a strong propensity to assume six coordination whereas calcium ion preferentially assumes a coordination greater than six. Likewise, water molecules attached to magnesium ion are held more rigidly than those of calcium ion, thus calcium ion is more accommodating in the exchange of water for negative ligands. PMID:2818858

Deerfield, D W; Lapadat, M A; Spremulli, L L; Hiskey, R G; Pedersen, L G

1989-06-01

286

Hydrate detection  

SciTech Connect

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)

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

1992-06-01

287

Hydrate detection  

SciTech Connect

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)

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

1992-01-01

288

Ultrathin calcium silicate hydrate nanosheets with large specific surface areas: synthesis, crystallization, layered self-assembly and applications as excellent adsorbents for drug, protein, and metal ions.  

PubMed

A simple and low-cost solution synthesis is reported for low-crystalline 1.4 nm tobermorite-like calcium silicate hydrate (CSH) ultrathin nanosheets with a thickness of ~2.8 nm and with a large specific surface area (SSA), via a reaction-rate-controlled precipitation process. The BET SSA of the CSH ultrathin nanosheets can reach as high as 505 m(2) g(-1) . The CSH ultrathin nanosheets have little cytotoxicity and can be converted to anhydrous calcium silicate (ACS) ultrathin nanosheets with a well preserved morphology via a heat treatment process. The crystallinity of CSH ultrathin nanosheets can be improved by solvothermal treatment in water/ethanol binary solvents or a single solvent of water, producing well-crystalline 1.1 nm tobermorite-like CSH nanobelts or nanosheets. CSH ultrathin nanosheets acting as building blocks can self-assemble into layered nanostructures via three different routes. The CSH ultrathin nanosheets are investigated as promising adsorbents for protein (hemoglobin, Hb), drug (ibuprofen, IBU), and metal ions (Cr(3+) , Ni(2+) , Cu(2+) , Zn(2+) , Cd(2+) , Pb(2+) ). The highest adsorbed percentages of Hb and IBU are found to be 83% and 94%, respectively. The highest adsorption capacities of Hb and IBU are found to be as high as 878 milligram Hb per gram CSH and 2.2 gram IBU per gram CSH, respectively. The ppm level metal ions can be totally adsorbed from aqueous solution in just a few minutes. Thus, the CSH ultrathin nanosheets are a promising candidate as excellent adsorbents in the biomedical field and for waste water treatment. Several empirical laws are summarized based on the adsorption profiles of Hb and IBU using CSH ultrathin nanosheets as the adsorbent. Furthermore, the ACS ultrathin nanosheets as adsorbents for Hb protein and IBU drug are investigated. PMID:23585365

Wu, Jin; Zhu, Ying-Jie; Chen, Feng

2013-04-15

289

Uptake of Cm(III) and Eu(III) by calcium silicate hydrates: a solution chemistry and time-resolved laser fluorescence spectroscopy study.  

PubMed

The interaction of the two chemical homologues [Cm(III) and Eu(III)] with calcium silicate hydrates (CSH phases) at pH 13.3 has been investigated in batch-type sorption studies using Eu(III) and complemented with time-resolved laser fluorescence spectroscopy (TRLFS) using Cm(III). The sorption data for Eu(III) reveal fast sorption kinetics and a strong uptake by CSH phases with distribution ratios of (6 +/- 3) x 10(5) L kg(-1). Three different Cm(III) species have been identified: A nonfluorescing species, which was identified as a curium hydroxide (surface) precipitate, and two fluorescing Cm(III)/CSH-sorbed species. The fluorescing sorbed species have characteristic emission spectra with main peak maxima at 618.9 and 620.9 nm and fluorescence emission lifetimes of 289 +/- 11 and 1482 +/- 200 micros, respectively. From the fluorescence lifetimes, it was calculated that the two fluorescing Cm(III) species have one or two and no water molecules left in their first coordination sphere, suggesting that these species are incorporated into the CSH structure. A structural model for Cm(III) and Eu(III) incorporation into CSH phases is proposed based on the substitution for Ca at two different types of sites in the CSH structure. PMID:12953867

Tits, Jan; Stumpf, Thorsten; Rabung, Thomas; Wieland, Erich; Fanghnel, Thomas

2003-08-15

290

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)

We apply in-situ synchrotron X-ray diffraction to study the transformation of calcium monosulfoaluminate 14-hydrate Ca4Al2O6(SO4)14H2O [monosulfate-14] to hydrogarnet Ca3Al2(OH)12 on the saturated water vapor pressure curve up to 250 C. We use an aqueous slurry of synthetic ettringite Ca6Al2(SO4)3(OH)1226H2O as the starting material; on heating, this decomposes at about 115 C to form monosulfate-14 and bassanite CaSO40.5H2O. 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.

Meller, Nicola; Kyritsis, Konstantinos; Hall, Christopher

2009-10-01

291

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

NASA Astrophysics Data System (ADS)

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 37C. 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.

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

2011-07-01

292

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

PubMed

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, dipped for 5 min in CP solutions at 0%, 0.5%, 1%, and 2% (w/v) either alone or in combination with 0.05% (w/v) SC, were stored at 3 and 10 degrees C for up to 14 d. Color, firmness, and microflora population were measured at 1, 7, and 14 d of storage. Results showed that CP alone had no significant effect on the browning of cut apples. Even though SC significantly inhibited tissue browning initially, the apple slices turned brown during storage at 10 degrees C. The combination of CP and SC was able to inhibit apple browning during storage. Samples treated with the combination of SC with CP did not show any detectable yeast and mold growth during the entire storage period at 3 degrees C. At 10 degrees C, yeast and mold count increased on apple slices during storage while CP reduced the increase. However, high concentrations of CP reduced the efficacy of SC in inactivating E. coli inoculated on apples. Overall, our results suggested that combination of SC with 0.5% and 1% CP could be used to inhibit tissue browning and maintain firmness while reducing microbial population. Practical Application: Apple slices, which contain antioxidants and other nutrient components, have emerged as popular snacks in food service establishments, school lunch programs, and for family consumption. However, the further growth of the industry is limited by product quality deterioration caused by tissue browning, short shelf-life due to microbial growth, and possible contamination with human pathogens during processing. Therefore, this study was conducted to develop treatments to reduce microbial population and tissue browning of "Granny Smith" apple slices. Results showed that an antimicrobial compound, sodium chlorite, is effective in not only eliminating microbes but also inhibiting tissue browning of apple slices. However, the compound caused tissue softening and its antibrowning effect was short-lived, lasting only for a few days. Combination of the compound with a calcium-containing food additive was able to improve firmness and freshness of apple slices while reducing population of Escherichia coli artificially inoculated on samples and inhibiting the growth of yeast and mold during storage. PMID:20492244

Guan, Wenqiang; Fan, Xuetong

2010-03-01

293

Midbrain dopaminergic neurons generate calcium and sodium currents and release dopamine in the striatum of pups  

PubMed Central

Midbrain dopaminergic neurons (mDA neurons) are essential for the control of diverse motor and cognitive behaviors. However, our understanding of the activity of immature mDA neurons is rudimentary. Rodent mDA neurons migrate and differentiate early in embryonic life and dopaminergic axons enter the striatum and contact striatal neurons a few days before birth, but when these are functional is not known. Here, we recorded Ca2+ transients and Na+ spikes from embryonic (E16E18) and early postnatal (P0P7) mDA neurons with dynamic two-photon imaging and patch clamp techniques in slices from tyrosine hydroxylase-GFP mice, and measured evoked dopamine release in the striatum with amperometry. We show that half of identified E16P0 mDA neurons spontaneously generate non-synaptic, intrinsically driven Ca2+ spikes and Ca2+ plateaus mediated by N- and L-type voltage-gated Ca2+ channels. Starting from E18P0, half of the mDA neurons also reliably generate overshooting Na+ spikes with an abrupt maturation at birth (P0 = E19). At that stage (E18P0), dopaminergic terminals release dopamine in a calcium-dependent manner in the striatum in response to local stimulation. This suggests that mouse striatal dopaminergic synapses are functional at birth.

Ferrari, Diana C.; Mdzomba, Baya J.; Dehorter, Nathalie; Lopez, Catherine; Michel, Francois J.; Libersat, Frederic; Hammond, Constance

2012-01-01

294

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

USGS Publications Warehouse

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 21-24C). 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).

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

1980-01-01

295

Crystallization and aggregation behaviors of calcium carbonate in the presence of poly(vinylpyrrolidone) and sodium dodecyl sulfate.  

PubMed

An anionic surfactant interacts strongly with a polymer molecule to form a self-assembled structure, due to the attractive force of the hydrophobic association and electrostatic repulsion. In this crystallization medium, the surfactant-stabilized inorganic particles adsorbed on the polymer chains, as well as the bridging effect of polymer molecules, controlled the aggregation behavior of colloidal particles. In this presentation, the spontaneous precipitation of calcium carbonate (CaCO3) was conducted from the aqueous systems containing a water-soluble polymer (poly(vinylpyrrolidone), PVP) and an anionic surfactant (sodium dodecyl sulfate, SDS). When the SDS concentrations were lower than the onset of interaction between PVP and SDS, the precipitated CaCO3 crystals were typically hexahedron-shaped calcite; the increasing SDS concentration caused the morphologies of CaCO3 aggregates to change from the flower-shaped calcite to hollow spherical calcite, then to solid spherical vaterite. These results indicate that the self-organized configurations of the polymer/surfactant supramolecules dominate the morphologies of CaCO3 aggregates, implying that this simple and versatile method expands the morphological investigation of the mineralization process. PMID:16853360

Shen, Qiang; Wei, Hao; Wang, Liancheng; Zhou, Yong; Zhao, Ying; Zhang, Zhiqing; Wang, Dujin; Xu, Guiying; Xu, Duanfu

2005-10-01

296

THE ROLE OF INTRACELLULAR SODIUM (Na+) IN THE REGULATION OF CALCIUM (Ca2+)-MEDIATED SIGNALING AND TOXICITY  

PubMed Central

It is known that activated N-methyl-D-aspartate receptors (NMDARs) are a major route of excessive calcium ion (Ca2+) entry in central neurons, which may activate degradative processes and thereby cause cell death. Therefore, NMDARs are now recognized to play a key role in the development of many diseases associated with injuries to the central nervous system (CNS). However, it remains a mystery how NMDAR activity is recruited in the cellular processes leading to excitotoxicity and how NMDAR activity can be controlled at a physiological level. The sodium ion (Na+) is the major cation in extracellular space. With its entry into the cell, Na+ can act as a critical intracellular second messenger that regulates many cellular functions. Recent data have shown that intracellular Na+ can be an important signaling factor underlying the up-regulation of NMDARs. While Ca2+ influx during the activation of NMDARs down-regulates NMDAR activity, Na+ influx provides an essential positive feedback mechanism to overcome Ca2+-induced inhibition and thereby potentiate both NMDAR activity and inward Ca2+ flow. Extensive investigations have been conducted to clarify mechanisms underlying Ca2+-mediated signaling. This review focuses on the roles of Na+ in the regulation of Ca2+-mediated NMDAR signaling and toxicity.

Yu, Xian-Min; Groveman, Bradley R; Fang, Xiao-Qian; Lin, Shuang-Xiu

2010-01-01

297

Photoresponsive ion extraction/release systems: dynamic ion optodes for calcium and sodium based on photochromic spiropyran.  

PubMed

Photoresponsive ion extraction/release systems (PRIONERS) represent a highly interesting tool for the localized and time-controlled chemical perturbation of biological materials. We report here on our first results on phototriggered calcium and sodium exchanging materials. Such materials exist in two distinct states ("on" and "off"), depending on the wavelength of illumination. We used a combination of spectroscopic and electrochemical methods to obtain a better understanding of the dynamic processes involved in the triggered ion-exchange reaction upon activation of the photoactive compound. The driving force for the ion exchange is the light-induced acidity change of the chromoionophore. Activation with UV light generates a species in the membrane with an increased pKa. Protons are pulled into the membrane, and at the same time, ions are expelled. The selectivity of the system is determined by the employed ionophore. In contrast to photoresponsive ionophore-based systems, the concept presented here is applicable for virtually any ion of interest for which an ionophore exists. PMID:23387291

Mistlberger, Gnter; Xie, Xiaojiang; Pawlak, Marcin; Crespo, Gastn A; Bakker, Eric

2013-02-22

298

Photoresponsive Ion Extraction/Release Systems: Dynamic Ion Optodes for Calcium and Sodium Based on Photochromic Spiropyran  

PubMed Central

Photoresponsive ion extraction/release systems (PRIONERS) represent a highly interesting tool for the localized and time-controlled chemical perturbation of biological materials. We report here on our first results on phototriggered calcium and sodium exchanging materials. Such materials exist in two distinct states (on and off), depending on the wavelength of illumination. We used a combination of spectroscopic and electrochemical methods to obtain a better understanding of the dynamic processes involved in the triggered ion-exchange reaction upon activation of the photoactive compound. The driving force for the ion exchange is the light-induced acidity change of the chromoionophore. Activation with UV light generates a species in the membrane with an increased pKa. Protons are pulled into the membrane, and at the same time, ions are expelled. The selectivity of the system is determined by the employed ionophore. In contrast to photoresponsive ionophore-based systems, the concept presented here is applicable for virtually any ion of interest for which an ionophore exists.

2013-01-01

299

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

PubMed

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

Bautista-Gallego, J; Arroyo-Lpez, F N; Durn-Quintana, M C; Garrido-Fernandez, A

2008-07-01

300

Effect of Azadirachta indica (neem), sodium thiosulphate and calcium chloride on changes in nitrogen transformations and inhibition of nitrification in soil incubated under laboratory conditions  

Microsoft Academic Search

A laboratory experiment was conducted to examine the effects of nitrification inhibitors (NIs) neem seedcake (Azadirachta indica) (NSC), sodium thiosulphate (Na2S2O3) and calcium chloride (CaCl2) on changes in NH4+N, inhibition of nitrification and recovery of applied nitrogen (N) in soil. Surface soil samples of 015cm were collected from an arable field, amended with urea N (UN) at the rate 200mgNkg?1,

M. Kaleem Abbasi; Munazza Hina; Majid Mahmood Tahir

2011-01-01

301

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

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

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

1964-01-01

302

Trace Element Analysis as an Exploration Tool for Unconfined Class 2 Hydrate Deposits  

NASA Astrophysics Data System (ADS)

Hydrate system analysis, analogous to hydrocarbon system analysis, is based on confirming significant gas flux, suitable thickness of hydrate stability zone, and suitably porous and permeable hydrate 'trap' beds in which economically significant hydrate crystallization may take place. Unconfined Class 2 hydrate deposits, which form by crystallization of dissolved natural gas in more porous and permeable sediments whose pore fluids may vent from the seafloor carry the dissolved rejected material. Analysis of superficial pore or vent water may provide a sensitive means of suggesting whether the water was once associated with hydrate crystallization. The rejection of dissolved ions and compounds during carbon dioxide hydrate precipitation on a chilled surface was determined to quantify the reject rate of specific materials from the hydrate matrix. Seawater and seawater doped with boric acid (H3BO3, MW 61.83 g/mol) and sodium borate decahydrate (Na2B4O7*10H2O, MW 381.37 g/mol) were used as crystallization solvents. Initial boron concentrations ranged from 4.1 to 27mg/L. Hydrate formation occurred with significant rejection of boron from the hydrate matrix, increasing the concentration in the crystallizing fluid. The initial boron concentration level did not affect the rejection efficiency, determined by comparing the initial concentration of boron to the concentration in the hydrate melt water. In addition to boron, naturally occurring calcium and magnesium concentration levels were also studied and showed a similar concentration reduction. Our experiments have shown that non-ionic dissolved species that occur in sediment pore water, in which hydrate may form, are rejected and concentrated during hydrate formation. The measurement of NaCl may provide a clue to the water having once been involved in subjacent hydrate formation, but other species that do not have additional crystallization opportunities in the sediment may be better clues to the extent of a hydrate formation. Identification of characteristic indicators of hydrate system participation would allow rapid sampling and analysis of seafloor water samples to be used as an exploration tool.

Johnson, A. D.; Max, M. P.; Osegovic, J. P.; Brazel, L.; Tatro, S.

2007-12-01

303

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

SciTech Connect

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.

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

2012-02-15

304

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

PubMed

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

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

2009-03-05

305

Characteristics of sodium and calcium conductance changes produced by membrane depolarization in an Aplysia neurone.  

PubMed Central

1. The time course and voltage dependence of Na and Ca conductance changes produced by depolarization of the soma of the neurone R15 in the abdominal ganglion of Aplysia juliana were examined at temperatures of 10--14 degrees C. 2. During a maintained depolarization, Na currents turned on then decayed (inactivated). Inactivation was exponential with time constant tauh. Activation (after correction for inactivation) was reasonably well described by the expression G'Na(t) = G'Na (infinity) (1 - exp [-t/taum])3 over a wide range of potentials. 3. taum and tauh were both voltage dependent. In the range -20 to +40 mV, taum varied from 5 to 0.5 msec and tauh from 25 to 8 msec (13.5 degrees C). Steady-state Na conductance (corrected for inactivation) was voltage dependent also, increasing sigmoidally with depolarization to a maximum of 25--30 muS at +10 to +20 mV. Half-maximal Na conductance occurred at a membrane potential of -8 mV and from -15 to -5 mV, a 5 mV change in membrane potential produced an e-fold change in steady-state Na conductance. 4. Steady-state inactivation of Na conductance (hNa(infinity)) was voltage dependent with half-inactivation occurring at a membrane potential of -32 mV. Recovery from Na inactivation followed an exponential time course with a voltage-dependent time constant. 5. During a maintained depolarization Ca currents activated then decayed (inactivated) more slowly than Na currents. The decay was exponential with time constant tauH. The decay of Ca current was not an artifact porduced by an outward current. The amplitude of calcium tail currents, produced by voltage steps back to epsilonK at different times during the decay of ICa, decayed also with a time constant close to tauH. 6. Ca conductance (after correction for inactivation) could be described approximately by the expression G'Ca(t) = G'Ca(infinity) (1 - exp [-t/tauM])p but it was necessary to vary p from 1 to 2 at different potentials. No value of p gave as good a fit to this model as that obtained for Na currents. 7. taum and tauH were voltage dependent. In the range of potentials from 0 to +60 mV, tauM varied from 9 to 5 msec and tauH from 300 to 50 msec (13.5 degrees C). Steady-state Ca conductance (corrected for inactivation) was voltage dependent also, increasing sigmoidally with depolarization to a maximum of 10--15 muS at +30 to +40 mV. Half-maximal Ca conductance occurred at a membrane potential of +12 mV, and from +10 to +20 mV a 6 mV change in membrane potential produced an e-fold change in Ca conductance. 8. Steady-state inactivation of Ca conductance (hCa(infinity)) varied with holding potential (VH). Half-inactivation occurred with depolarization to -20 mV. At potentials more negative than -40 mV, hCa(infinity) was less than at -40 mV, i.e. hyperpolarization produced Ca 'inactivation'. 9... Images Fig. 1 Fig. 5 Fig. 7

Adams, D J; Gage, P W

1979-01-01

306

Unmodified CdSe Quantum Dots Induce Elevation of Cytoplasmic Calcium Levels and Impairment of Functional Properties of Sodium Channels in Rat Primary Cultured Hippocampal Neurons  

PubMed Central

Background The growing applications of nanotechnologic products, such as quantum dots (QDs), increase the likelihood of exposure. Furthermore, their accumulation in the bioenvironment and retention in cells and tissues are arousing increasing worries about the potentially harmful side effects of these nanotechnologic products. Previous studies concerning QD cytotoxicity focused on the reactive oxygen species produced by QDs. Cellular calcium homeostasis dysregulation caused by QDs may be also responsible for QD cytotoxicity. Meanwhile the interference of QDs with voltage-gated sodium channel (VGSC) current (INa) may lead to changes in electrical activity and worsen neurotoxicologic damage. Objective We aimed to investigate the potential for neurotoxicity of cadmium selenium QDs in a hippocampal neuronal culture model, focusing on cytoplasmic calcium levels and VGSCs function. Methods We used confocal laser scanning and standard whole-cell patch clamp techniques. Results We found that a) QDs induced neuron death dose dependently; b) cytoplasmic calcium levels were elevated for an extended period by QD treatment, which was due to both extracellular calcium influx and internal calcium release from endoplasmic reticulum; and c) QD treatment enhanced activation and inactivation of INa, prolonged the time course of activation, slowed INa recovery, and reduced the fraction of available VGSCs. Conclusion Results in this study provide new insights into QD toxicology and reveal potential risks of their future applications in biology and medicine.

Tang, Mingliang; Xing, Tairan; Zeng, Jie; Wang, Huili; Li, Chenchen; Yin, Shuting; Yan, Dan; Deng, Hongmin; Liu, Jin; Wang, Ming; Chen, Jutao; Ruan, Di-Yun

2008-01-01

307

Effects of sodium bicarbonate and 1,25-dihydroxy-cholecalciferol on calcium and phosphorus balances in the rat  

SciTech Connect

Metabolic balance studies were undertaken to determine whether sodium bicarbonate (NaHCO/sub 3/) supplements (4.5 mmol/day) altered 7-day cumulative calcium (Ca) phosphorus (P) balances in growing rats consuming either a basal diet providing 0.6% Ca and 0.3% P, or this diet plus 1,25-dihydroxycholecalciferol (40 ng 1,25(OH)/sub 2/D/sub 3//day). Feeding bicarbonate lowered urinary Ca but raised fecal Ca so that Ca balance became less positive. However, 1,25(OH)/sub 2/D/sub 3/ increased net absorption of Ca and P to the same degree when given to control rats and rats consuming bicarbonate. Nevertheless, bicarbonate-fed rats had lower net Ca absorption than controls, even when treated with high doses of 1,25(OH)/sub 2/D/sub 3/. Changes in net Ca absorption induced by bicarbonate may occur at a point in the gut distal to the duodenum since duodenal /sup 45/Ca absorption was decreased by bicarbonate feeding. The present results show that bicarbonate consumption depressed net Ca absorption in the rat. The effect appears to be independent of changes in 1,25(OH)/sub 2/D/sub 3/ metabolism because it is manifest in animals receiving high doses of 1,25(OH)/sub 2/D/sub 3/, which stimulate alimentary Ca absorption maximally, and because bicarbonate-fed rats are able to respond normally to exogenous 1,25(OH)/sub 2/D/sub 3/ by increasing their net absorption of Ca and P. In view of this demonstration that NaHCO/sub 3/ supplements elevate fecal Ca loss in the rat, it is suggested that studies should be undertaken to determine whether bicarbonate exerts similar adverse effects on Ca balance in humans.

Goulding, A.; McIntosh, J.; Campbell, D.

1984-04-01

308

Determination of sodium, potassium, calcium, magnesium, zinc, and iron in emulsified egg samples by flame atomic absorption spectrometry.  

PubMed

In this study, oil-in-water formulations were optimized to determine sodium, potassium, calcium, magnesium, zinc, and iron in emulsified egg samples by flame atomic absorption spectrometry (FAAS). This method is simpler and requires fewer reagents when compared with other sample pre-treatment procedures and allows the calibration to be carried out using aqueous standards. Different oily phases such as corn oil, decyl oleate and octyl stearate were tested, as well as Tween 80, Triton X-100 and Triton 114 were analyzed as surfactants. The optimum type and proportion of formulations were determined and their use depended on the element studied. The emulsion preparation was performed by a conventional method that involves mixing both phases at 60 degrees C by magnetic stirring and phase inversion to change the water-to-oil ratio by increasing the volume of the surfactant-water external phase and correspondingly decreasing the volume of internal phase. The accuracy of the method was further confirmed by determining the metals in a whole egg powder CRM and recoveries ranged from 97.5% for Mg to 102.2% for Na, with relative standard deviations lower than 2.3%. The precision of the procedures was determined through repeatability (intra-day precision) and intermediate precision (inter-day). The repeatability presented RSD values lower than 4.2%. The intermediate precision was evaluated using the RSD and F-test. The RSD values to intermediate precision was lower than 5.3% and the computed F-values were lower than tabulated F-values, indicating no significant difference between the results obtained on different days. The proposed method including, sample emulsification for subsequent metal determination for FAAS, has proved to be sensitive, reproducible, simple and economical. PMID:20006088

Ieggli, C V S; Bohrer, D; do Nascimento, P C; de Carvalho, L M; Garcia, S C

2010-01-15

309

Sodium and bone health: impact of moderately high and low salt intakes on calcium metabolism in postmenopausal women.  

PubMed

High salt intake is a well-recognized risk factor for osteoporosis because it induces calciuria, but the effects of salt on calcium metabolism and the potential impact on bone health in postmenopausal women have not been fully characterized. This study investigated adaptive mechanisms in response to changes in salt and calcium intake in postmenopausal women. Eleven women completed a randomized cross-over trial consisting of four successive 5-wk periods of controlled dietary intervention, each separated by a minimum 4-wk washout. Moderately low and high calcium (518 versus 1284 mg) and salt (3.9 versus 11.2 g) diets, reflecting lower and upper intakes in postmenopausal women consuming a Western-style diet, were provided. Stable isotope labeling techniques were used to measure calcium absorption and excretion, compartmental modeling was undertaken to estimate bone calcium balance, and biomarkers of bone formation and resorption were measured in blood and urine. Moderately high salt intake (11.2 g/d) elicited a significant increase in urinary calcium excretion (p = 0.0008) and significantly affected bone calcium balance with the high calcium diet (p = 0.024). Efficiency of calcium absorption was higher after a period of moderately low calcium intake (p < 0.05) but was unaffected by salt intake. Salt was responsible for a significant change in bone calcium balance, from positive to negative, when consumed as part of a high calcium diet, but with a low calcium intake, the bone calcium balance was negative on both high and low salt diets. PMID:18410231

Teucher, Birgit; Dainty, Jack R; Spinks, Caroline A; Majsak-Newman, Gosia; Berry, David J; Hoogewerff, Jurian A; Foxall, Robert J; Jakobsen, Jette; Cashman, Kevin D; Flynn, Albert; Fairweather-Tait, Susan J

2008-09-01

310

Effect of calcium on immobilization of rice ( Oryza sativa L.) peroxidase for bioassays in sodium alginate and Agarose gel  

Microsoft Academic Search

The direct immobilization of soluble peroxidase isolated and partially purified from shoots of rice seedlings in calcium alginate\\u000a beads and in calcium agarose gel was carried out. Peroxidase was assayed for guaiacol oxidation products in presence of hydrogen\\u000a peroxide. The maximum specific activity and immobilization yield of the calcium agarose immobilized peroxidase reached 2,200\\u000a U mg?1 protein (540 mU cm?3

Sareeta Nahakpam; Puneeta Singh; Kavita Shah

2008-01-01

311

Sodium cyanate-induced opening of calcium-activated potassium currents in hippocampal neuron-derived H19-7 cells  

Microsoft Academic Search

We investigated the chemical toxic agent sodium cyanate (NaOCN) on the large conductance calcium-activated potassium channels (BKCa) on hippocampal neuron-derived H19-7 cells. The whole-cell and cell-attach configuration of patch-clamp technique were applied to investigate the BKCa currents in H19-7 cells in the presence of NaOCN (0.3mM). NaOCN activated BKCa channels on H19-7 cells. The single-channel conductance of BKCa channels was

Chin-Wei Huang; Chao-Ching Huang; Mei-Han Huang; Sheng-Nan Wu; Yi-Jung Hsieh

2005-01-01

312

Interactive effects of sodium chloride and calcium chloride on the accumulation of proline and glycinebetaine in peanut ( Arachis hypogaea L.)  

Microsoft Academic Search

Many plants, including peanut (Arachis hypogaea L.), when exposed to salinity stress produce the osmoticants: proline and glycinebetaine. Calcium ions also play a role in osmoprotection. During germination of peanut seeds subjected to NaCl salinity stress, proline and glycinebetaine concentrations in the embryonic axis increased continuously. A further increase in glycinebetaine concentration was observed with the addition of calcium chloride

C Girija; B. N Smith; P. M Swamy

2002-01-01

313

Slurry Consistency and In-situ Synchrotron X-ray Diffraction during the Early Hydration of Portland Cements with Calcium Chloride  

Microsoft Academic Search

Class A and H oil well cements are compared at 25 and 50 C with 0%, 1%, 2%, and 4% CaCl. Up to 4% CaCl accelerated Class A thickening, but 4% led to slower thickening than 2% for Class H. CS hydration in the two cements responded differently to CaCl. CaCl always accelerated aluminate hydration. For Class A, CaCl accelerated

Andrew C. Jupe; Angus P. Wilkinson; Karen Luke; Gary P. Funkhouser

2008-01-01

314

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

PubMed Central

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.

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

1999-01-01

315

Furnace injection of pressure hydrated lime  

Microsoft Academic Search

Pressure-hydrators are used to produce a highly reactive sorbent with a surface area and pore size distribution which enables maximum utilization of available calcium. The hydrator vessel is operated at pressures of 90 to 150 psig with temperatures up to 300°F. Upon expulsion of the reacted quicklime\\/saturated steam mix from the hydrator, water trapped inside the pore network of the

G. F. Weber; M. H. Bobman; T. P. Dorchak

1985-01-01

316

Furnace Injection of Pressure Hydrated Lime.  

National Technical Information Service (NTIS)

Pressure-hydrators are used to produce a highly reactive sorbent with a surface area and pore size distribution which enables maximum utilization of available calcium. The hydrator vessel is operated at pressures of 90 to 150 psig with temperatures up to ...

G. F. Weber M. H. Bobman T. P. Dorchak

1985-01-01

317

Physico-chemical and sensory properties of reduced-fat mortadella prepared with blends of calcium, magnesium and potassium chloride as partial substitutes for sodium chloride.  

PubMed

Blends of calcium, magnesium and potassium chloride were used to partially replace sodium chloride (50-75%) in reduced-fat mortadella formulations. The presence of calcium chloride reduced the emulsion stability, cooking yield, elasticity and cohesiveness and increased hardness; however, it yielded the best sensory acceptance when 50% NaCl was replaced by 25% CaCl(2) and 25% KCl. There was no effect of the salt substitutes on mortadella color, appearance and aroma. All salt combinations studied showed stable lipid oxidation during its shelf life. The use of a blend with 1% NaCl, 0.5% KCl and 0.5% MgCl(2) resulted in the best emulsion stability, but the worst scores for flavor. This study suggests that it is possible to reduce the sodium chloride concentration by 50% in reduced-fat mortadella using the studied salt combinations with necessary adjustments to optimize the sensory properties (MgCl(2) 25%; KCl 25%) or emulsion stability (CaCl(2) 25%; KCl 25%). PMID:21645975

Horita, C N; Morgano, M A; Celeghini, R M S; Pollonio, M A R

2011-05-19

318

The use of refrigerants for reflux boiling direct contact heat exchanging in heat-of-fusion storage using salt hydrates  

SciTech Connect

As was early proposed by Carlsson, Stymne and Wettermark certain refrigerants can be used as media for reflux boiling direct contact heat exchanging in heat-of-fusion storage using salt hydrates. Suitable couples of storage medium and heat transfer medium are those for which the two liquids are immiscible and the density of the liquid phase of the heat transfer medium is higher than that of the liquid phase of the storage medium. The combinations of the salt hydrate calcium chloride hexahydrate, m.p. 30/sup 0/C, and the two refrigerants R113 and R12B1 meet these requirements and were previously studied by Carlsson and Schmidt who found R12B1 to be a more favourable heat transfer medium than R113 when combined with the pertinent salt hydrate. Arrhenius et al. have considered several couples of storage medium and heat transfer medium for latent heat exchange by direct contact vapourization. The refrigerant R11 and the sodium acetate trihydrate, which meet the density requirements mentioned above, are reported to be of particular interest. The present paper summarizes the results from a study where the two couples of the salt hydrate calcium chloride hexahydrate and the refrigerant R12B1 and that of sodium thiosulphate pentahydrate, m.p. 48/sup 0/C, and R12B1 are investigated. The aim is to clarify the technical benefits of this heat exchange method in comparison to other types of heat exchange techniques.

Carlsson, B.; Schmidt, A.

1983-12-01

319

5MW Toronto HALT (Hydrate Addition at Low Temperature) pilot plant testing: Test results: Part 1-A. [Hydrate addition at low temperature for the removal of SO  

Microsoft Academic Search

''Hydrate Addition at Low Temperature'' of HALT is a dry calcium- based hydrate injection process for the removal of SO 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

M. Babu; R. Forsythe; D. Kerivan; K. Lee; R. Herbert; D. Kanary

1988-01-01

320

Effects of sodium tripolyphosphate and sodium carbonate on the selective flocculation of diasporic-bauxite in the presence of calcium and magnesium ions  

Microsoft Academic Search

In this study, sedimentation tests for individual minerals and artificially mixed minerals and bauxite ores were carried out to understand the effects of sodium tripolyphosphate (STPP) on the selective flocculation of diasporic-bauxite in the presence of Ca2+ and Mg2+ ions. It was found that STPP can mitigate the detrimental effects of Ca2+ and Mg2+ ions on the dispersion of diaspore

Wang Yuhua; Sun Daxiang; Wang Liguang; Zhou Yulin

2011-01-01

321

Preparation and structure evolution of bowknot-like calcium carbonate particles in the presence of poly(sodium 4-styrene sulfate).  

PubMed

Calcium carbonate particles with a novel bowknot-like superstructure were fabricated in the presence of poly(sodium 4-styrene sulfate) (PSS) and under the assistance of ultrasonication during the initial reaction stage. X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and field-emission scanning electron microscopy (FE-SEM) equipped with energy-dispersive X-ray (EDX) were used to characterize the particles. Results demonstrated that the bowknot-like calcium carbonate particles were mainly composed of amorphous calcium carbonate (ACC) and some amounts of calcite and vaterite. Ultrasound irradiation associated with the presence of PSS affects the mesoscale crystallization, resulting in stepwise growth of the earlier bundles to the bowknot. Morphology evolution and dissolution of the bowknot particle were observed in different media, confirming that PSS and Ca(2+) ions in the solutions could accelerate and resist the transformation process, respectively. In the presence of PSS, ACC prefers to transform into vaterite. PMID:22867860

Xie, Lili; Song, Xiaoxue; Tong, Weijun; Gao, Changyou

2012-07-16

322

Effects of A Voltage Sensitive Calcium Channel Blocker and A Sodium-Calcium Exchanger Inhibitor on Apoptosis of Motor Neurons in Adult Spinal Cord Slices  

PubMed Central

Objective: The apoptosis of motor neurons is a critical phenomenon in spinal cord injuries. Adult spinal cord slices were used to investigate whether voltage sensitive calcium channels and Na+/Ca2+ exchangers play a role in the apoptosis of motor neurons. Materials and Methods: In this experimental research, the thoracic region of the adult mouse spinal cord was sliced using a tissue chopper and the slices were incubated in a culture medium in the presence or absence of N/L type voltage sensitive calcium channels blocker (loperamide, 100 M) or Na+/Ca2+ exchangers inhibitor(bepridil, 20 M) for 6 hours. 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium (MTT) staining was used to assess slice viability while morphological features of apoptosis in motor neurons were studied using fluorescent staining. Results: After 6 hours in culture, loperamideand bepridil not only increased slice viability, but also prevented motor neuron apoptosis and significantly increased the percentage of viable motor neurons in the ventral horns of the spinal cord. Conclusion: The results of this study suggest that voltage sensitive calcium channels and Na+/Ca2+ exchanger might be involved in the apoptosis of motor neurons in adult spinal cord slices.

Momeni, Hamid Reza; Jarahzadeh, Mahsa

2012-01-01

323

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

Microsoft Academic Search

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

Andrew C. Jupe; Angus P. Wilkinson; Karen Luke; Gary P. Funkhouser

2008-01-01

324

Measurement and prediction of gas hydrate and hydrated salt equilibria in aqueous ethylene glycol and electrolyte solutions  

Microsoft Academic Search

A recently developed method in modelling electrolyte solutions is extended to include phase behaviour of aqueous solutions containing hydrated salts (e.g., calcium chloride) and organic hydrate inhibitors (e.g., ethylene glycol). A novel salt precipitation model applicable to various hydrated salts is presented. The precipitation model takes into account various precipitates of hydrated salts over a wide range of temperature (i.e.,

Rahim Masoudi; Bahman Tohidi; Ali Danesh; Adrian C. Todd; Ross Anderson; Rod W. Burgass; Jinhai Yang

2005-01-01

325

Circadian Models of Serum Potassium, Sodium, and Calcium Concentrations in Healthy Individuals and Their Application to Cardiac Electrophysiology Simulations at Individual Level  

PubMed Central

In the article a brief description of the biological basis of the regulation of human biological clocks was presented in order to introduce the role of circadian rhythms in physiology and specifically in the pharmacological translational tools based on the computational physiology models to motivate the need to provide models of circadian fluctuation in plasma cations. The main aim of the study was to develop statistical models of the circadian rhythm of potassium, sodium, and calcium concentrations in plasma. The developed ion models were further tested by assessing their influence on QT duration (cardiac endpoint) as simulated by the biophysically detailed models of human left ventricular cardiomyocyte. The main results are model equations along with an electronic supplement to the article that contains a fully functional implementation of all models.

Fijorek, Kamil; Puskulluoglu, Miroslawa

2013-01-01

326

Chloral Hydrate  

MedlinePLUS

... after surgery for pain and to treat alcohol withdrawal.This medication is sometimes prescribed for other uses; ... TesTape or Clinistix to test your urine for sugar. Do not use Clinitest because chloral hydrate can ...

327

Efficacy of a dentifrice containing 5% potassium nitrate and 1500 PPM sodium monofluorophosphate in a precipitated calcium carbonate base on dentinal hypersensitivity.  

PubMed

The effect on dentinal hypersensitivity from the use of a dentifrice containing 5.0% potassium nitrate, 1500 ppm sodium monofluorophosphate in a precipitated calcium carbonate (PCC) base over an eight-week period was compared to a placebo dentifrice without potassium nitrate. A total of forty-eight subjects were entered into the study and stratified into two balanced groups according to their baseline mean thermal (air blast) and tactile (Yeaple Probe) sensitivity scores. The two groups were randomly assigned to use either the potassium nitrate/PCC dentifrice or a placebo dentifrice without potassium nitrate. The two groups were well balanced with regard to their mean baseline thermal tactile sensitivity scores, sex and age. Subjects were instructed to brush their teeth twice daily (morning and evening) for one minute with their assigned dentifrice and a commercially available soft-bristled toothbrush. Dentinal hypersensitivity examinations, which included tactile and thermal sensitivity, were conducted at baseline, four weeks, and eight weeks. Examinations were conducted by the same dental examiner (TS) on the subjects at each examination. After four weeks' use of their assigned products, those subjects in the potassium nitrate/PCC dentifrice group demonstrated statistically significant improvements (p < 0.0001), as compared to the placebo dentifrice without potassium nitrate, in tactile and thermal sensitivity. After eight weeks' use of their assigned products, those subjects in the potassium nitrate/PCC dentifrice group again demonstrated statistically significant improvements (p < 0.0001), in tactile and thermal sensitivity, as compared to the placebo dentifrice without potassium nitrate. Thus it can be concluded from this study that the use of a dentifrice containing 5.0% potassium nitrate and 1500 ppm sodium monofluorophosphate in a precipitated calcium carbonate (PCC) base is a clinically effective method for reducing dentinal hypersensitivity. PMID:9835829

Schiff, T; Dos Santos, M; Laffi, S; Yoshioka, M; Baines, E; Brasil, K D; McCool, J J; De Vizio, W

1998-01-01

328

Slurry Consistency and In-situ Synchrotron X-ray Diffraction during the Early Hydration of Portland Cements with Calcium Chloride  

SciTech Connect

Class A and H oil well cements are compared at 25 and 50 C with 0%, 1%, 2%, and 4% CaCl{sub 2}. Up to 4% CaCl{sub 2} accelerated Class A thickening, but 4% led to slower thickening than 2% for Class H. C{sub 3}S hydration in the two cements responded differently to CaCl{sub 2}. CaCl{sub 2} always accelerated aluminate hydration. For Class A, CaCl{sub 2} accelerated early Ca(OH){sub 2} precipitation, but sometimes reduced the amount at longer times. This may be coupled to C-S-H gel composition changes. For Class H, Ca(OH){sub 2} precipitation changes nonlinearly with CaCl{sub 2} concentration. Ettringite to monosulfate conversion and Friedel's salt formation were sometimes seen.

Jupe, A.C.; Wilkinson, A.P.; Luke, K.; Funkhouser, G.P. (Halliburton); (GIT)

2008-07-08

329

Formation of ettringite, Ca6Al2(SO4)3(OH)12.26H2O, AFt, and monosulfate, Ca4Al2O6(SO4).14H2O, 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)

In the hydration of calcium aluminum oxide-gypsum mixtures, i.e., Ca3Al2O6, Ca12Al14O33 and CaSO4.2H2O, the reaction products can be ettringite, Ca6Al2(SO4)3(OH)12.26H2O, monosulfate, Ca4Al2O6(SO4).14H2O, or the calcium aluminum oxide hydrate, Ca4Al2O7.19H2O. Ettringite is formed if sufficient CaSO4.2H2O is present in the mixture. Ettringite is converted to monosulfate when all CaSO4.2H2O is consumed in the synthesis of ettringite. The reactions were investigated in the temperature range 25-170C 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.

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

2004-06-01

330

Effects of acute sodium fluoride exposure on kidney function, water homeostasis, and renal handling of calcium and inorganic phosphate.  

PubMed

Fluoride compounds are abundant and widely distributed in the environment at a variety of concentrations. Further, fluoride induces toxic effects in target organs such as the liver and kidney. In this study, we performed an early analysis of renal function using a clearance technique in Wistar rats acutely exposed to fluoride at a plasma concentration of 0.625?g/ml. Our results revealed that fluoride, at a concentration close to the concentration present in the serum after environmental exposure, induced a significant tubular dysfunction, resulting in diluted urine, impaired protein reabsorption, and increased calcium and phosphate urinary excretion. Our work demonstrates that even acute exposures to low concentrations of NaF may induce renal damage and confirms that, after exposure, the kidney participates directly in the calcium and phosphate deficiencies observed in fluoride-exposed populations. PMID:23400904

Santoyo-Sanchez, Mitzi Paola; del Carmen Silva-Lucero, Maria; Arreola-Mendoza, Laura; Barbier, Olivier Christophe

2013-02-12

331

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

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

Elmore, Amy R

2003-01-01

332

Conceptual HALT (Hydrate Addition at Low Temperature) Scaleup Design: Capital and Operating Costs: Part 5.  

National Technical Information Service (NTIS)

Hydrate addition at low temperature (or the HALT process) is a retrofit option for moderate SO2 removal efficiency in coal burning utility plants. This dry FGD process involves injecting calcium based dry hydrate particles into flue gas ducting downstream...

M. Babu D. Kerivan C. Hendrick B. Kosek D. Tackett

1988-01-01

333

The effect of sodium zeolite A and cholecalciferol on plasma levels of 1,25-dihydroxycholecalciferol, calcium, and phosphorus in commercial Leghorns.  

PubMed

Three experiments were conducted to determine possible mechanisms involved in improving eggshell quality with sodium zeolite A (SZA) (trade name Ethacal feed component), and cholecalciferol (vitamin D3) by studying the effect of dietary supplementation of SZA and vitamin D3 on plasma 1,25-dihydroxycholecalciferol [1,25-(OH)2 D3], ionic calcium (Ca++), normalized calcium (nCa++), total calcium (TCa), percentage Ca++ to TCa (PCa++), pH, and phosphorus (P). In Experiment 1 (2 x 2 factorial arrangement of treatments), two levels of SZA (0 and .75%) and two levels of vitamin D3 (0 and 175 ICU/kg) were fed. In Experiment 2, five levels of vitamin D3 (100 to 500 ICU/kg) and two levels of SZA (0 and .75%) were fed using a 2 x 5 factorial arrangement of treatments. In Experiment 3, hens were fed two levels of SZA (0 and .75%). Blood samples were collected at 0 (Experiments 1, 2, and 3), 7, 14, and 21 h (Experiment 3) postoviposition (POP). In Experiments 1 and 2, decreasing vitamin D3 decreased plasma 1,25-(OH)2 D3 and P. Plasma TCa decreased when 0 ICU vitamin D3 was fed (Experiment 1), but was not affected by vitamin D3 level in Experiment 2. Supplemental SZA had no effect on plasma 1,25-(OH)2 D3, TCa, or P in Experiments 1 and 2. In Experiment 3, plasma 1,25-(OH)2 D3 and P peaked at 14 h POP, but Ca++ was lowest at 14 h POP. Circadian rhythms for plasma 1,25-(OH)2 D3, Ca++, and P were not affected by SZA. There were no significant effects due to dietary SZA on plasma 1,25-(OH)2 D3, TCa, Ca++, PCa++, nCa++, pH, or P.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1319050

Frost, T J; Roland, D A; Barnes, D G; Laurent, S M

1992-05-01

334

Transitions of calcium carbonate crystals controlled by self-assembly supermolecule of ?-cyclodextrin and sodium dodecyl benzene sulfonate  

Microsoft Academic Search

The transitions from vaterite to calcite and from vaterite to aragonite, were found with the anionic surfactant sodium dodecyl benzene sulfonate and ?-cyclodextrin as a template, respectively, when the experimental temperature was controlled at 90C. The transition from calcite to aragonite was found when the experimental temperature was controlled at 120C. The molar ratio of 1:1 and 1:2 supermolecules composed

Zhaodong Nan; Xiangna Chen; Qianqian Yang; Zhiying Chen

2010-01-01

335

Influence of Salt Stress on the Nutritional State of Cordyline fruticosa var. Red Edge, 2: Sodium, Potassium, Calcium, and Magnesium  

Microsoft Academic Search

The aim of this trial was to study the nutritional behavior generated by modifications in the salt concentration in the nutrient solution used for the fertigation of Cordyline fruticosa var. Red Edge plants. Four treatments were tested: T1 [control, 1.5 dS m, 14.3 mmol L sodium chloride (NaCl)]; T2 (2.5 dS m, 22.2 mmol L NaCl); T3 (3.5 dS m,

B. M. Plaza; S. Jimnez; M. T. Lao

2012-01-01

336

21 CFR 184.1763 - Sodium hydroxide.  

Code of Federal Regulations, 2013 CFR

...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 Food Chemicals Codex, 3d...

2013-04-01

337

The hydration of tricalcium silicate in the presence of colloidal silica  

Microsoft Academic Search

Reactions of colloidal silica fumes with calcium hydroxide or hydrating tricalcium silicate (C3S) have been studied using calorimetry, chemical analyses, and scanning electron microscopy. Silica fume reacts immediately with calcium hydroxide forming a colloidal calcium silicate hydrate (C-S-H) similar to that formed by the hydration of C3S. When excess silica is present it reacts with C-S-H already formed to produce

Zhao-Qi Wu; J. F. Young

1984-01-01

338

Chemical characteristics of mineral trioxide aggregate and its hydration reaction  

PubMed Central

Mineral trioxide aggregate (MTA) was developed in early 1990s and has been successfully used for root perforation repair, root end filling, and one-visit apexification. MTA is composed mainly of tricalcium silicate and dicalcium silicate. When MTA is hydrated, calcium silicate hydrate (CSH) and calcium hydroxide is formed. Formed calcium hydroxide interacts with the phosphate ion in body fluid and form amorphous calcium phosphate (ACP) which finally transforms into calcium deficient hydroxyapatite (CDHA). These mineral precipitate were reported to form the MTA-dentin interfacial layer which enhances the sealing ability of MTA. Clinically, the use of zinc oxide euginol (ZOE) based materials may retard the setting of MTA. Also, the use of acids or contact with excessive blood should be avoided before complete set of MTA, because these conditions could adversely affect the hydration reaction of MTA. Further studies on the chemical nature of MTA hydration reaction are needed.

2012-01-01

339

Influence of finely ground limestone on cement hydration  

Microsoft Academic Search

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

Jean Pra; Sophie Husson; Bernard Guilhot

1999-01-01

340

TRPM8 and Nav1.8 sodium channels are required for transthyretin-induced calcium influx in growth cones of small-diameter TrkA-positive sensory neurons  

PubMed Central

Background Familial amyloidotic polyneuropathy (FAP) is a peripheral neuropathy caused by the extracellular accumulation and deposition of insoluble transthyretin (TTR) aggregates. However the molecular mechanism that underlies TTR toxicity in peripheral nerves is unclear. Previous studies have suggested that amyloidogenic proteins can aggregate into oligomers which disrupt intracellular calcium homeostasis by increasing the permeability of the plasma membrane to extracellular calcium. The aim of the present study was to examine the effect of TTR on calcium influx in dorsal root ganglion neurons. Results Levels of intracellular cytosolic calcium were monitored in dorsal root ganglion (DRG) neurons isolated from embryonic rats using the calcium-sensitive fluorescent indicator Fluo4. An amyloidogenic mutant form of TTR, L55P, induced calcium influx into the growth cones of DRG neurons, whereas wild-type TTR had no significant effect. Atomic force microscopy and dynamic light scattering studies confirmed that the L55P TTR contained oligomeric species of TTR. The effect of L55P TTR was decreased by blockers of voltage-gated calcium channels (VGCC), as well as by blockers of Nav1.8 voltage-gated sodium channels and transient receptor potential M8 (TRPM8) channels. siRNA knockdown of TRPM8 channels using three different TRPM8 siRNAs strongly inhibited calcium influx in DRG growth cones. Conclusions These data suggest that activation of TRPM8 channels triggers the activation of Nav1.8 channels which leads to calcium influx through VGCC. We suggest that TTR-induced calcium influx into DRG neurons may contribute to the pathophysiology of FAP. Furthermore, we speculate that similar mechanisms may mediate the toxic effects of other amyloidogenic proteins such as the ?-amyloid protein of Alzheimer's disease.

2011-01-01

341

Sulfur/alkali/calcium oxide sorbent interaction in pressurized coal combustors  

SciTech Connect

Modeling and bench-scale experiments have been performed related to the capture of fuel-bound sulfur by calcium-based sorbents injected into pressurized coal combustors. Sorbent types tested include two limestones, a dolomite, a slaked lime, and a pressure-hydrated dolomite, with and without several sodium-based mineral promoters present. Sulfur capture data have been obtained at pressures up to 10 atm. These data have been incorporated into the porous sorbent model of Simons and Garman. Modeling of lean turbine combustors indicates that in-situ injection of pressure-hydrated sorbents should remove greater than 50 percent of the SO/sub 2/ at 10 atm and 0.5 sec residence time. Furthermore the presence of alkali minerals in the coal can enhance the intrinsic reactivity by a factor of two or more. Conveniently, the calcium sorbent can serve as a site for alkali condensation and removal.

Garman, A.R.; Boni, A.A.; Campbell, J.P.; Simons, G.A.; Johnson, S.A.

1985-01-01

342

Fluid and salt supplementation effect on body hydration and electrolyte homeostasis during bed rest and ambulation  

NASA Astrophysics Data System (ADS)

Bed rest (BR) induces significant urinary and blood electrolyte changes, but little is known about the effect of fluid and salt supplements (FSS) on catabolism, hydration and electrolytes. The aim was to measure the effect of FSS on catabolism, body hydration and electrolytes during BR. Studies were done during 7 days of a pre-bed rest period and during 30 days of a rigorous bed rest period. Thirty male athletes aged, 24.67.6 years were chosen as subjects. They were divided into three groups: unsupplemented ambulatory control subjects (UACS), unsupplemented bed rested subjects (UBRS) and supplemented bed rested subjects (SBRS). The UBRS and SBRS groups were kept under a rigorous bed rest regime for 30 days. The SBRS daily took 30 ml water per kg body weight and 0.1 sodium chloride per kg body weight. Plasma sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) levels, urinary Na, K, Ca and Mg excretion, plasma osmolality, plasma protein level, whole blood hemoglobin (Hb) and hematocrit (Hct) level increased significantly ( p?0.05), while plasma volume (PV), body weight, body fat, peak oxygen uptake, food and fluid intake decreased significantly ( p?0.05) in the UBRS group when compared with the SBRS and UACS groups. In contrast, plasma and urinary electrolytes, osmolality, protein level, whole blood Hct and Hb level decreased significantly ( p?0.05), while PV, fluid intake, body weight and peak oxygen uptake increased significantly ( p?0.05) in the SBRS group when compared with the UBRS group. The measured parameters did not change significantly in the UACS group when compared with their baseline control values. The data indicate that FSS stabilizes electrolytes and body hydration during BR, while BR alone induces significant changes in electrolytes and body hydration. We conclude that FSS may be used to prevent catabolism and normalize body hydration status and electrolyte values during BR.

Zorbas, Yan G.; Kakurin, Vassily J.; Kuznetsov, Nikolai A.; Yarullin, Vladimir L.

2002-06-01

343

Comparative efficacy of dentifrice containing sodium monofluorophosphate + calcium glycerophosphate and non-fluoridated dentifrice: A randomized, double-blind, prospective study  

PubMed Central

Background: The efficacy of fluoridated dentifrices in caries prevention has been well documented and research into various formulations continues for a more effective dentifrice. This study evaluated the anti-caries and anti-plaque efficacy of a dentifrice containing sodium monofluorophosphate (1000 ppm) and calcium glycerophosphate, and compared it with a non-fluoridated dentifrice. Materials and Methods: A total of 595 school children (1215 years) were divided into test (302 children) and control (293 children) groups. The test group used the dentifrice containing sodium monofluorophosphate (1000 ppm) and calcium glycerophosphate, whereas the control group was given a placebo dentifrice. Oral examination for dental caries and plaque assessment was carried out at the start of the study and the children were followed up semiannually up to 18 months. Data were analyzed using repeated-measure analysis of variance (ANOVA) followed by one-way ANOVA. Results: The values for decayed missing filled teeth (DMFT) increased from baseline to 18 month examination from 4.432.03 and 4.672.25 (P=0.175) to 5.842.29 and 5.132.30 (P=0.001) for control and test groups, respectively. Similarly, the increase in decayed missing filled surface (DMFS) values were from 6.424.10 and 7.064.77 (P=0.082) to 8.644.51 and 7.925.07 (P=0.095) for test and control groups, respectively. The mean DMFT and DMFS values increased for both the groups; however, the increase was less in test group as compared to control group. The baseline plaque score reduced from 2.940.72 and 2.910.72 (P=0.679), respectively, for control and test groups to 1.330.46 and 0.910.38 (P<0.001), respectively, at 18 month examination. Conclusion: Results revealed that the test dentifrice was effective in inhibiting the progression of plaque and control of dental caries as compared to the placebo dentifrice.

Damle, Satyawan G.; Deoyani, D; Bhattal, Hiteshwar; Yadav, Renu; Lomba, Ashish

2012-01-01

344

Effect of dietary moisture and sodium content on urine composition and calcium oxalate relative supersaturation in healthy miniature schnauzers and labrador retrievers.  

PubMed

The aim of this series of studies was to evaluate two possible feeding strategies as methods for reducing the risk of calcium oxalate (CaOx) formation in two breeds of healthy dog. The studies compared the effect of dietary moisture (Study 1) and dietary sodium (Na), (Study 2) on urine composition of labrador retrievers (LR) and miniature schnauzers (MS). A nutritionally complete dry dog food was fed to 16 dogs (eight LR, eight MS; Study 1) and 15 dogs (seven LR, eight MS; Study 2) for 24 days (Study 1), or 36 days (Study 2). The dogs were fed the diet alone (7% moisture, 0.06 g Na/100 kcal), or supplemented with deionised water to 73% moisture (Study 1), or dietary Na, to deliver 0.20 or 0.30 g Na per 100 kcal (Study 2). Urine pH, volume, specific gravity, and concentrations of 12 analytes were measured for each dog. Urinary relative supersaturations (RSS) with CaOx were calculated from these values. The effects of supplemental Na or water were established using t tests (Study 1) or analysis of variance, and multiple range tests (least significant difference) (Study 2); P<0.05 was considered significant. Increasing dietary moisture significantly increased total moisture intake (P=0.001), and reduced urine specific gravity (P=0.003), urinary oxalate concentration (P=0.04), and CaOx relative supersaturation (P=0.04) in the MS. Urinary parameters remained unchanged in the LR, indicating that feeding a high moisture diet may reduce the risk of CaOx formation in high-risk breeds. Increasing dietary Na led to production of urine with a significantly lower CaOx RSS in both breeds, indicating that sodium supplementation to dry diet formats may reduce the risk of CaOx formation. These feeding strategies should be considered when evaluating methods for preventing CaOx formation within high-risk groups. PMID:12589739

Stevenson, A E; Hynds, W K; Markwell, P J

2003-04-01

345

SLC24A5 encodes a trans-Golgi network protein with potassium-dependent sodium-calcium exchange activity that regulates human epidermal melanogenesis.  

PubMed

A non-synonymous single nucleotide polymorphism in the human SLC24A5 gene is associated with natural human skin color variation. Multiple sequence alignments predict that this gene encodes a member of the potassium-dependent sodium-calcium exchanger family denoted NCKX5. In cultured human epidermal melanocytes we show using affinity-purified antisera that native human NCKX5 runs as a triplet of approximately 43 kDa on SDS-PAGE and is partially localized to the trans-Golgi network. Removal of the NCKX5 protein through small interfering RNA-mediated knockdown disrupts melanogenesis in human and murine melanocytes, causing a significant reduction in melanin pigment production. Using a heterologous expression system, we confirm for the first time that NCKX5 possesses the predicted exchanger activity. Site-directed mutagenesis of NCKX5 and NCKX2 in this system reveals that the non-synonymous single nucleotide polymorphism in SLC24A5 alters a residue that is important for NCKX5 and NCKX2 activity. We suggest that NCKX5 directly regulates human epidermal melanogenesis and natural skin color through its intracellular potassium-dependent exchanger activity. PMID:18166528

Ginger, Rebecca S; Askew, Sarah E; Ogborne, Richard M; Wilson, Stephen; Ferdinando, Dudley; Dadd, Tony; Smith, Adrian M; Kazi, Shubana; Szerencsei, Robert T; Winkfein, Robert J; Schnetkamp, Paul P M; Green, Martin R

2007-12-28

346

Hydrothermal treatment of naturally contaminated maize in the presence of sodium metabisulfite, methylamine and calcium hydroxide; effects on the concentration of zearalenone and deoxynivalenol.  

PubMed

Fusarium toxin-contaminated ground maize was hydrothermally treated in the presence of different combinations of chemicals in order to simultaneously reduce zearalenone (ZEA) and deoxynivalenol (DON) concentrations. Treatments were carried out in a laboratory conditioner at 80 C and 17 % moisture. Six different treatments were performed, consisting of 3 doses of methylamine (MMA; 2.5, 5 and 10 g/kg maize) at a constant dose of 5 g sodium metabisulfite (SBS)/kg, either with or without the addition of 20 g calcium hydroxide (Ca(OH)2)/kg. The used maize was contaminated with approximately 45.99 mg DON/kg and 3.46 mg ZEA/kg. Without the addition of Ca(OH)2, DON reductions reached approximately 82% after 1-min treatment and the toxin disappeared nearly completely after 10 min when 2.5 or 5 g MMA were applied. ZEA concentrations were only marginally affected. In the presence of Ca(OH)2, reductions in DON concentrations were lower, but were enhanced by increasing doses of MMA. ZEA concentrations were reduced by 72, 85 and 95% within the first 5 min of the treatment at MMA dosages of 2.5, 5 and 10 g/kg maize, respectively. The application of SBS in combination with a strong alkaline during hydrothermal treatment seems to be a promising approach to simultaneously decontaminate even high amounts of DON and ZEA in ground maize and may contribute to reduce the toxin load of diets. PMID:23536360

Rempe, Inga; Kersten, Susanne; Valenta, Hana; Dnicke, Sven

2013-03-28

347

Studies of a Salt Hydrate Heat Storage System.  

National Technical Information Service (NTIS)

Crystallization of a one and two component system for thermal storage by fusion heat of salt hydrates has been investigated for sodium sulfate (10H2O); sodium thiosulfate (5H2O) and sodium acetate (3H2O). A continuous input of small crystals which grew an...

L. Christensen N. Cho G. Keyser D. Lamb E. Wedum

1978-01-01

348

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

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

Lavialle-Defaix, Cline; Moignot, Bndicte; Legros, Christian; Lapied, Bruno

2010-01-07

349

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

SciTech Connect

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.

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

350

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

NASA Astrophysics Data System (ADS)

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 from 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 SO2 and NOx emissions by previous investigators gives the rough approximation that alkaline emission rates are of the order of the SO2 + NOx emissions in the western United States and that they are much smaller than SO2 + NOx in the eastern United States. This approximation is substantiated by data on Ca/(SO4 + NO3) for wet deposition for National Atmospheric Deposition Program sites.

Gillette, Dale A.; Stensland, Gary J.; Williams, Allen L.; Barnard, William; Gatz, Donald; Sinclair, Peter C.; Johnson, Tezz C.

1992-12-01

351

Ultrasonic and Hypersonic Properties of Ionic Hydrate Melts.  

National Technical Information Service (NTIS)

Ultrasonic and Brillouin scattering measurements have been used to establish the relaxation properties of zinc chloride, zinc nitrate and calcium nitrate hydrate melts in the frequency range 5 MHz to 12 GHz. A distribution of relaxation times is observed ...

R. Carpio F. Borsay C. Petrovic E. Yeager

1975-01-01

352

Cytosolic free Ca2+ during operation of sodium-calcium exchange in guinea-pig heart cells.  

PubMed Central

1. Membrane current generated by the Na(+)-Ca2+ exchange mechanism was recorded in single guinea-pig ventricular myocytes using the whole-cell voltage-clamp technique and the intracellular free calcium concentration ([Ca2+]i) was monitored using the fluorescent probe Indo-1, applied intracellularly through a perfused patch pipette. The reversal potential of the exchanger (ENa, Ca) was measured from records of the 2 mM-Ni(2+)-sensitive current and used in an attempt to clamp [Ca2+]i at a level determined by the ionic compositions of the external and pipette solutions. 2. Measurements of ENa, Ca indicated that [Ca2+]i was close to that in the pipette solution when the holding potential was set at the ENa, Ca expected for a 3Na+:1Ca2+ exchanger. The measured value of ENa, Ca was more positive than the theoretical value when the membrane potential was held positive to ENa, Ca and the opposite was true when the holding potential was more negative than the expected ENa, Ca. 3. As Indo-1 diffused into the cell from the whole-cell clamp electrode, the intensities of the fluorescent signals measured at 405 and 480 nm increased with time, with no obvious saturation over a 10-45 min recording period. However, the ratio of these two signals reached a steady level within 5 min after rupture of the patch membrane, when the holding potential was set at the expected ENa, Ca of the exchanger. The intensity ratios measured using pipette solutions containing 600 and 803 nM [Ca2+] were almost equal to the ratios obtained extracellularly from internal solutions of identical compositions, but in experiments using pipette solutions having lower [Ca2+] the intensity ratios measured in myocytes were higher than those obtained extracellularly. 4. If the membrane was depolarized or hyperpolarized, the fluorescence ratio either increased or decreased, respectively. These changes in the fluorescence ratio were virtually blocked by the extracellular application of 2 mM-Ni2+. 5. When the concentration of bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) in the recording pipette was reduced from 30 to 1 mM, an increase in [Ca2+]i was observed during a depolarizing ramp pulse. The Ca2+ influx estimated by integrating the 2 mM-Ni(2+)-sensitive current during the pulse correlated with the increase in [Ca2+]i estimated from Indo-1 using the extracellular calibration curve, but the values of the influx determined directly from Indo-1 fluorescence were always larger than those calculated from the exchanger current.(ABSTRACT TRUNCATED AT 400 WORDS)

Noma, A; Shioya, T; Paver, L F; Twist, V W; Powell, T

1991-01-01

353

The nature of the hydration products in hardened cement pastes  

Microsoft Academic Search

An understanding of the performance of portland cement-based materials requires knowledge at the microstructural level. Developments in the instrumentation of several techniques have led to improved understanding of the composition, morphology, and spatial distribution of the various products of cement hydration. In particular, our understanding of the nature of the nearly amorphous calcium silicate hydrate (CSH) phases which are

I. G Richardson

2000-01-01

354

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

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-

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

1999-01-01

355

XPS of fast-frozen hematite colloids in NaCl aqueous solutions: I. Evidence for the formation of multiple layers of hydrated sodium and chloride ions induced by the {001} basal plane  

SciTech Connect

The influence of the {001} basal plane of hematite on the composition of fast-frozen centrifuged wet pastes of hematite prepared at pH 4 and 9 and at ionic strengths of 0, 10 and 100 mM NaCl was investigated by x-ray photoelectron spectroscopy. Two hematite preparations consisted of micrometer-sized platelets with 42% (HEM-1) and 95% (HEM-8) of the surface terminated by the {001} basal plane. A third preparation of spherical shape with no recognizable crystal plane (HEM-control) was used as a control to these experiments. All hematite samples responded to changes in pH and ionic strength, showing that acid/base reactions of surface hydroxyl groups control the composition of the paste. The HEM-1 and HEM-8 sample exhibited divergent properties at the highest ionic strength (100 mM) with energy loss features in the Na 1s and Cl 2p spectra and an important water content. As the spectra were typical of hydrated Na+ and Cl- ions and that the surface concentrations were unusually large, the HEM-1 and HEM-8 samples are proposed to induce the formation of a three-dimensional distribution of these ions in the paste. The sodium, chloride and water content was also correlated to the fraction of the {001} basal plane present in the sample and provided evidence for an approximate stochiometric Na:Cl:H2O ratio of 1:1:2. The {001} basal plane of hematite is consequently proposeD to be the cause of this feature.

Shchukarev, Andrei; Boily, Jean F.; Felmy, Andrew R.

2007-12-13

356

Standard enthalpies of formation of francium hydroxide hydrates  

Microsoft Academic Search

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

Burylev

1995-01-01

357

Effect of additives on formation of natural gas hydrate  

Microsoft Academic Search

The formation of natural gas hydrate (NGH) is studied in this work. Kinetics data of hydrate formation with no agitation were collected at various concentrations of the aqueous solutions with different additives such as alkylpolyglucside, sodium dodecyl benzene sulfonate and potassium oxalate monohydrate. Various kinds of additive increased the formation rates of NGH and its storage capacity and reduced the

C. S Zhang; S. S Fan; D. Q Liang; K. H Guo

2004-01-01

358

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

PubMed

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

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

2013-07-16

359

Hydrates of hydrocarbons  

SciTech Connect

Gas hydrates are solid crystalline compounds of water and methane that are similar to snow. They form in and block gas wells and lines and cause fouling of heat exchangers when the gas is cooled. Here, finally, is long-awaited information detailing the successful methods for not only removing gas hydrates but also for preventing their reforming. This book addresses methods of hydrate removal and, most importantly, prevention of hydrate build-up. New topics of using hydrate properties for new technologies and production of gas from natural gas hydrate deposits are also discussed. Information specific to hydrate formation in gas includes: conditions and area of hydrate-carrying rock; estimating gas amounts in gas hydrate deposits; the role of natural gas hydrates in global changes; the physical principles and models of gas hydrate deposit development; results of the Messoyakhi gas hydrate field development; and hydrates in space. Contents includes: Physical-chemical aspects; Properties of hydrates; Mechanism of hydrate formation; Technological appellations of hydrates; Natural hydrates of gases; Conclusion; and Bibliography.

Makogon, Y.F. [Moscow Petroleum Inst. (Russian Federation)

1997-12-31

360

Effect of surfactant on the formation and dissociation kinetic behavior of methane hydrate  

Microsoft Academic Search

The effects of anionic surfactant sodium dodecyl sulfate (SDS) on the formation\\/dissociation kinetic behaviors of methane hydrate have been studied experimentally, with an emphasis put on dissociation kinetic behavior below ice point. The experimental results on hydrate formation show that the formation rates of methane hydrate could be speeded up by adding SDS to water and a critical SDS concentration

W. Lin; G.-J. Chen; C.-Y. Sun; X.-Q. Guo; Z.-K. Wu; M.-Y. Liang; L.-T. Chen; L.-Y. Yang

2004-01-01

361

The kinetics of ettringite formation and dilatation in a blended cement with ?-hemihydrate and anhydrite as calcium sulfate  

Microsoft Academic Search

The phase formation, heat of hydration and dilatation in a blended cement consisting of 50 wt.% calcium aluminate cement, 25 wt.% Portland cement and 25 wt.% calcium sulfate were studied (w\\/c=1). The calcium sulfate was ?-hemihydrate, anhydrite and mixes of the two. Kinetic expressions describing the ettringite formation in the pastes with the pure calcium sulfates were found. Hydration reactions

Cecilie Evju; Staffan Hansen

2005-01-01

362

Molecular dynamics study of the effect of calcium ions on the monolayer of SDC and SDSn surfactants at the vapor/liquid interface.  

PubMed

The effect of Ca(2+) ions on the hydration shell of sodium dodecyl carboxylate (SDC) and sodium dodecyl sulfonate (SDSn) monolayer at vapor/liquid interfaces was studied using molecular dynamics simulations. For each surfactant, two different surface concentrations were used to perform the simulations, and the aggregation morphologies and structural details have been reported. The results showed that the aggregation structures relate to both the surface coverage and the calcium ions. The divalent ions can screen the interaction between the polar head and Na(+) ions. Thus, Ca(2+) ions locate near the vapor/liquid interface to bind to the headgroup, making the aggregations much more compact via the salt bridge. The potential of mean force (PMF) between Ca(2+) and the headgroups shows that the interaction is decided by a stabilizing solvent-separated minimum in the PMF. To bind to the headgroup, Ca(2+) should overcome the energy barrier. Among contributions to the PMF, the major repulsive interaction was due to the rearrangement of the hydration shell after the calcium ions entered into the hydration shell of the headgroup. The PMFs between the headgroup and Ca(2+) in the SDSn systems showed higher energy barriers than those in the SDC systems. This result indicated that SDSn binds the divalent ions with more difficulty compared with SDC, so the ions have a strong effect on the hydration shell of SDC. That is why sulfonate surfactants have better efficiency in salt solutions with Ca(2+) ions for enhanced oil recovery. PMID:21495650

Yan, Hui; Guo, Xin-Li; Yuan, Shi-Ling; Liu, Cheng-Bu

2011-04-15

363

Clathrate Hydrates in Nature  

Microsoft Academic Search

Scientific knowledge of natural clathrate hydrates has grown enormously over the past decade, with spectacular new findings of large exposures of complex hydrates on the sea floor, the development of new tools for examining the solid phase in situ, significant progress in modeling natural hydrate systems, and the discovery of exotic hydrates associated with sea floor venting of liquid CO2.

Keith C. Hester; Peter G. Brewer

2009-01-01

364

Microwave cooking properties of chicken patties enriched with calcium  

Microsoft Academic Search

The experiment was designed to partially replace sodium lactate with calcium lactate in microwave oven cooked chicken patties with an objective to reduce sodium level and enrich the product with calcium. The study aims to determine the effect of incorporation of 3.3% sodium lactate (SL), 0.25% calcium lactate (CL) and 1.65% sodium lactate along with 0.125% calcium lactate (SL+CL) on

B. M. NAVEENA; M. MUTHUKUMAR; A. R. SEN; S. VAITHIYANATHAN; Y. BABJI

365

Hydrate characterization research overview  

Microsoft Academic Search

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

Malone

1993-01-01

366

Effect of Azadirachta indica (neem), sodium thiosulphate and calcium chloride on changes in nitrogen transformations and inhibition of nitrification in soil incubated under laboratory conditions.  

PubMed

A laboratory experiment was conducted to examine the effects of nitrification inhibitors (NIs) neem seed-cake (Azadirachta indica) (NSC), sodium thiosulphate (Na?S?O?) and calcium chloride (CaCl?) on changes in NH?(+)?N, inhibition of nitrification and recovery of applied nitrogen (N) in soil. Surface soil samples of 0-15 cm were collected from an arable field, amended with urea N (UN) at the rate 200 mg N kg?, UN+NSC, UN+Na?S?O? and UN+CaCl? and incubated at 22C periodically over 50 d. Soil without any amendment was used as check (control). Results indicated that more than 58% of N applied as NH?? disappeared over a period of 50 d from the soil mineral-N pool. Some of this N (21%) was accumulated as NO??-N while the remaining N was unaccounted for. Addition of nitrification inhibitors NSC, Na?S?O?, and CaCl? resulted in a decrease in the extent of NH?(+) disappearance by 35%, 44% and 30%, respectively. In the treatment receiving UN alone, 56 mg NO??-N kg? was accumulated over 50 d (maximum 93 mg kg?) indicated an active nitrification. Application of nitrification inhibitors NSC, Na?S?O?, and CaCl? with UN inhibited nitrification by 54%, 64%, and 59%, respectively. Apparent N recovery (ANR) in the treatment receiving UN alone was 63% that substantially increased to 83%, 89% and 76% in the treatments receiving UN+NSC, UN+Na?S?O?, and UN+CaCl?, respectively indicating 32%, 41% and 20% increase in N recovery. Among three NIs tested, Na?S?O? proved superior in inhibiting nitrification and increasing ANR. The study demonstrated that application of NSC, Na?S?O?, and CaCl? which are cheap and easily available NIs inhibited nitrification and improved N recovery efficiency of applied N in an arable soil very effectively. It is suggested that these inhibitors should be tested under field conditions for increasing NUE and improving crop productivity. PMID:21146192

Abbasi, M Kaleem; Hina, Munazza; Tahir, Majid Mahmood

2010-12-13

367

Normal pregnancy: mechanisms underlying the paradox of a ouabain-resistant state with elevated endogenous ouabain, suppressed arterial sodium calcium exchange, and low blood pressure.  

PubMed

Endogenous cardiotonic steroids (CTS) raise blood pressure (BP) via vascular sodium calcium exchange (NCX1.3) and transient receptor-operated channels (TRPCs). Circulating CTS are superelevated in pregnancy-induced hypertension and preeclampsia. However, their significance in normal pregnancy, where BP is low, is paradoxical. Here we test the hypothesis that vascular resistance to endogenous ouabain (EO) develops in normal pregnancy and is mediated by reduced expression of NCX1.3 and TRPCs. We determined plasma and adrenal levels of EO and the impact of exogenous ouabain in pregnancy on arterial expression of Na(+) pumps, NCX1.3, TRPC3, and TRPC6 and BP. Pregnant (embryonic day 4) and nonpregnant rats received infusions of ouabain or vehicle. At 14-16 days, tissues and plasma were collected for blotting and EO assay by radioimmunoassay (RIA), liquid chromatography (LC)-RIA, and LC-multidimensional mass spectrometry (MS3). BP (-8 mmHg; P < 0.05) and NCX1.3 expression fell (aorta -60% and mesenteric artery -30%; P < 0.001) in pregnancy while TRPC expression was unchanged. Circulating EO increased (1.14 0.13 nM) vs. nonpregnant (0.6 0.08 nM; P < 0.05) and was confirmed by LC-MS3 and LC-RIA. LC-MS3 revealed two previously unknown isomers of EO; one increased ?90-fold in pregnancy. Adrenal EO but not isomers were increased in pregnancy. In nonpregnant rats, similar infusions of ouabain raised BP (+24 3 mmHg; P < 0.001). In ouabain-infused rats, impaired fetal and placental growth occurred with no BP increase. In summary, normal pregnancy is an ouabain-resistant state associated with low BP, elevated circulating levels of EO, two novel steroidal EO isomers, and increased adrenal mass and EO content. Ouabain raises BP only in nonpregnant animals. Vascular resistance to the chronic pressor activity of endogenous and exogenous ouabain is mediated by suppressed NCX1.3 and reduced sensitivity of events downstream of Ca(2+) entry. The mechanisms of EO resistance and the impaired fetal and placental growth due to elevated ouabain may be important in pregnancy-induced hypertension (PIH) and preeclampsia (PE). PMID:22245773

Jacobs, Brandiese E; Liu, Yong; Pulina, Maria V; Golovina, Vera A; Hamlyn, John M

2012-01-13

368

?-Pyrolysis of crystalline sodium thiosulphate penta hydrate  

Microsoft Academic Search

Pure Na2S2O35H2O, was investigated carefully for its X-ray diffraction, IR-absorption spectra, UV\\/Vis-absorption spectra, thermogravimetric\\u000a analysis, differential thermal analysis before and after various gamma ray absorbed doses. Results obtained were explained,\\u000a compared and discussed in detail, leading to a mechanism for radiation damage in this system.

Morsy Abou Sekkina; El-Sayed El-Shereafy; A. Mashaly; M. El-Ashry

1998-01-01

369

CFBC ash hydration studies  

Microsoft Academic Search

Hydration studies on CFBC ashes have shown that the acetone technique to prevent hydration in stored samples is relatively effective, only allowing some slight degree of hydration over days in the presence of excess water. In the presence of large excesses of water sufficient to control temperature increases, the degree of bulk mixing has no effect on the degree of

Edward J. Anthony; Lufei Jia; Yinghai Wu

2005-01-01

370

Current understanding of cellulose ethers impact on the hydration of C 3A and C 3A-sulphate systems  

Microsoft Academic Search

The impact of cellulose ethers (CE) on C3A hydration was examined to support the understanding of the retarding effect of CE on cement hydration. In this sense, we successively studied the CE adsorption on ettringite and calcium hydroaluminates, and then the CE influence during C3A hydration in presence or absence of calcium sulphate. We emphasized a phase-specific adsorption of CE

J. Pourchez; P. Grosseau; B. Ruot

2009-01-01

371

Hydration products in peat-containing concrete  

SciTech Connect

This investigation was conducted to study the influence of transitional peat on the phase composition of the newly formed structures in peat concrete produced from a solution based on portland cement with calcium chloride and a gypsum-alumina binder added. The phase compositions of the new structures were determined by derivatographic and x-ray phase analysis, using IR spectroscopy and electron (in combination with microdiffraction) and scanning microscopy in individual cases. When peat-containing concrete is based on portland cement, the fundamental neoformations characteristic of this type of binder are accompanied by large amounts of peat organic-acid calcium salts and highly hydrated chelate complexes containing iron and aluminum hydroxides, which retard crystal growth. When a gypsum-alumina binder is employed, the peat components chelate with the aluminum hydroxide and have no perceptible influence on cement hydration products.

Klyusov, A.A.

1988-08-01

372

Hydrate characterization research overview  

SciTech Connect

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.

Malone, R.D.

1993-06-01

373

Clinical experience with sodium cellulose phosphate  

Microsoft Academic Search

There is currently no treatment program which is capable of correcting the basic abnormality of absorptive hypercalciuria, although several drugs are available which have been shown to restore normal calcium excretion. Sodium cellulose phosphate best meets the criteria for optimum therapy. When given orally, this non-absorbable ion exchange resin binds calcium and inhibits calcium absorption. However, this inhibition is caused

Charles Y. C. Pak; Michael J. Nicar; Faye Britton

1983-01-01

374

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

|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

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

2004-01-01

375

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

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

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

2004-01-01

376

Actonel with Calcium REMS Letter  

Center for Drug Evaluation (CDER)

Text Version... NDA) submitted under section 505(b) of the Federal Food, Drug, and Cosmetic Act (FDCA) for Actonel with Calcium, (risedronate sodium with ... More results from www.fda.gov/downloads/drugs/drugsafety

377

Modeling and simulation of cement hydration kinetics and microstructure development  

SciTech Connect

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.

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

378

Effects of Calcium Chloride on Growth, Membrane Permeability and Root Hydraulic Conductivity in Two Atriplex Species Grown at High (Sodium Chloride) Salinity  

Microsoft Academic Search

Calcium (Ca) has an important role in plant physiology, including involvement in the responses to salt stress, and controls numerous processes. To overcome the negative impact of high salinity, the addition of supplemental Ca to the growth medium as an ameliorative agent could be necessary. Atriplex halimus subsp. schweinfurthii and Atriplex canescens subsp. linearis were grown in hydroponic conditions to

Bouzid Nedjimi; Youcef Daoud

2009-01-01

379

Gas Hydrate Nucleation Processes  

NASA Astrophysics Data System (ADS)

The onset of gas hydrate nucleation is greatly affected by the thermal history of the water that forms its lattice structure. Hydrate formation experiments were performed in a 72 liter pressure vessel by bubbling carbon dioxide through a 1 liter column at hydrate formation pressures (1.4 to 3.7 MPa) and temperatures (275.0 to 278.0 K) to quantify this effect. They show that when even a fraction ( e. g. 20 %) of the water in which hydrate has formed was recently frozen and thawed, the overpressurization for nucleation was reduced by an average of 50 % versus experiments performed in distilled water. In those experiments where a lower overpressure is present when hydrate nucleated, they tended to form on the surface of bubbles, whereas when a higher amount of overpressure was necessary for hydrate to nucleate, they appeared to form abruptly on bubble surfaces as well as from the bulk liquid phase. In approximation of classical nucleation, hydrate formation could be described as occurring by the spontaneous joining together of arising components of the hydrate lattice. In water that was frozen, and kept at a low temperature (< 275 K), molecular simulation models predict the predominance of water molecules organized as penatmeters, a possible subunit of the hydrate lattice. Our results suggest that in nature, initiation of hydrate formation may be strongly influenced by temperature dependant pre-structuring of water molecules prior to their contact with gas.

David, R. E.; Zatsepina, O.; Phelps, T. J.

2003-12-01

380

Salt Toleration by Plants: Enhancement with Calcium  

Microsoft Academic Search

Bean plants subjected to a sodium chloride concentration about one-tenth that of seawater for 1 week suffered no damage if the calcium concentration of the nutrient solution was 1 millimole per liter or higher, but at lower calcium concentrations damage was severe and apparently due to a massive breakthrough of sodium into the leaves.

P. A. Lahaye; Emanuel Epstein

1969-01-01

381

The growth rate of gas hydrate from refrigerant R12  

SciTech Connect

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)

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

382

Influence of nucleation seeding on the hydration kinetics and compressive strength of alkali activated slag paste  

Microsoft Academic Search

Addition of pure calcium silicate hydrate (CSH) to alkali-activated slag (AAS) paste resulted in an earlier and larger hydration rate peak measured with isothermal calorimetry and a much higher compressive strength after 1d of curing. This is attributed to a nucleation seeding effect, as was previously established for Portland cement and tricalcium silicate pastes. The acceleration of AAS hydration by

Mija H. Hubler; Jeffrey J. Thomas; Hamlin M. Jennings

2011-01-01

383

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

PubMed Central

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 inameloblasts 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.

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

384

Alkaline stability of cellulose ethers and impact of their degradation products on cement hydration  

Microsoft Academic Search

Cellulose ethers are polymers frequently introduced into mortar formulations. This study allows to assess the potential role of cellulose ethers degradation on the alteration of the cement hydration kinetics. A retardation mechanism based on the calcium binding capacity of chelates is often proposed to describe the effects of some polysaccharides (e.g. sugars) on cement hydration. The alkaline stability of cellulose

J. Pourchez; A. Govin; P. Grosseau; R. Guyonnet; B. Guilhot; B. Ruot

2006-01-01

385

A molecular dynamics and microporomechanics study on the mechanical properties of major constituents of hydrated cement  

Microsoft Academic Search

Cement paste is the matrix material for concrete and cement based composites. This paper presents a molecular dynamics (MD) method for estimating mechanical properties of hydrated cement major constituents: calciumsilicatehydrate (CSH) structurally related tobermorite 14 and jennite, and calcium hydroxide (CH). Microporomechanics technique is used to calculate properties of two types of CSH, namely, low density (LD) and high density

Ahmed Al-Ostaz; W. Wub; A. H.-D. Chengc; C. R. Songd

2010-01-01

386

Restoration of calcium transport in the trypsin-treated (Ca+ + Mg2+)-dependent adenosine triphosphatase of sarcoplasmic reticulum exposed th sodium dodecyl sulfate.  

PubMed

When sarcoplasmic reticulum vesicles are exposed to trypsin for 1 min the adenosine triphosphatase (Mr = 102,000) is cleaved to fragments of Mr = 45,000 and 55,000. The purified ATPase, containing both fragments, transports Ca2+ when incorporated into vesicles containing excess phospholipid. The two fragments can only be dissociated in solutions containing 1% sodium dodecyl sulfate (SDS). Ca2+ transport activity is restored in SDS-dissociated preparations in a series of steps involving dilution with 5 volumes of 5% phospholipids in 0.75% sodium cholate, incubation in ice for 30 min, and passage through an anion exchange column. Vesicles formed in this procedure regain high Ca2+ transport activity if they are incubated in SDS solution at 24 degrees for less than 20 min. However, the extent of renaturation diminishes if the vesicles are incubated for longer periods and little acitivity is recovered in vesicles incubated longer than 60 min at 24 degrees. PMID:136448

MacLennan, D H; Khanna, V K; Stewart, P S

1976-11-25

387

Calcium Calculator  

MedlinePLUS

... Fun Stuff Fun Stuff Best for Bones Food Calcium Calculator How much calcium do you get every day? Remember, you need ... Deal with Vitamin D List of Foods with Calcium & Vitamin D Calcium Calculator Fooling Around with Food ...

388

Effect of Green Waste Compost and Mycorrhizal Fungi on Calcium, Potassium, and Sodium Uptake of Woody Plants Grown Under Salt Stress  

Microsoft Academic Search

Sodium chloride is the most often used chemical to malt ice and snow on the roads and has negative effects on the roadside\\u000a environment. Searching for ways to improve the conditions for growth of trees and shrubs near the roads becomes an urgent\\u000a matter. One such method of improving growth conditions for plants under salinity might be to use organic

Adam Marosz

389

Rapid Inhibition by Sodium Azide of the Phosphoinositide-Mediated Calcium Response to Serotonin Stimulation in Human Platelets: Preservation in Alzheimer's Disease  

Microsoft Academic Search

The effect of sodium azide (NaN3) upon platelet Ca2+ signalling has been investigated. A 60 s preincubation with 1 mM NaN3 reduced the Ca2+ response to 1 ?M serotonin without a corresponding reduction in the responses to 52 mU\\/ml thrombin or 70 ?M ?-amyloid(2535) (A?(2535)). The effect of NaN3 upon the response to serotonin, which was not blocked by either

Henrietta L. M. Hedin; Sture Eriksson; Christopher J. Fowler

2000-01-01

390

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

Microsoft Academic Search

A search is being carried out for new calcium-based SO 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

Kenney

1996-01-01

391

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

SciTech Connect

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.

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

2008-10-06

392

Sodium - urine  

MedlinePLUS

The sodium urine test measures the amount of salt (sodium) in a urine sample. Sodium can also ... L/day), depending on how much fluid and salt you consume. The examples above are common measurements ...

393

Effect of superplasticizers on the hydration kinetic and mechanical properties of Portland cement pastes  

Microsoft Academic Search

Hydration of ordinary Portland cement in the presence of two different types of superplasticizers namely sodium lignosulfonate (LS) and naphthalene sulfonate-formaldehyde condensate (NSF) was studied using different experimental techniques. Superplasticized ordinary Portland cement pastes were prepared using the values of standard water of consistency with different additions of each type of superplasticizers used. Pastes were hydrated for different time intervals

Safaa M. A. El-Gamal; Fawzia M. Al-Nowaiser; Asmaa O. Al-Baity

394

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

SciTech Connect

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.

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

395

Hydrates of hydrocarbons  

Microsoft Academic Search

Gas hydrates are solid crystalline compounds of water and methane that are similar to snow. They form in and block gas wells and lines and cause fouling of heat exchangers when the gas is cooled. Here, finally, is long-awaited information detailing the successful methods for not only removing gas hydrates but also for preventing their reforming. This book addresses methods

Makogon

1997-01-01

396

Role of intracellular sodium in the regulation of intracellular calcium and contractility. Effects of DPI 201-106 on excitation-contraction coupling in human ventricular myocardium.  

PubMed Central

Experiments were performed to investigate the mechanism of action of DPI 201-106 on human heart muscle. In both control and myopathic muscles, DPI produced concentration-dependent increases in action potential duration, resting muscle tension, peak isometric tension, and duration of isometric tension. These changes were associated with increases in resting intracellular calcium and peak calcium transients as measured by aequorin. At higher concentrations of DPI, a second delayed Ca2+ transient (L') appeared. L' was inhibited by tetrodotoxin and ryanodine, suggesting that DPI acts at both the sarcolemma and the sarcoplasmic reticulum. DPI toxicity was manifested by after-glimmers and after-contractions reflecting a Ca2+-overload state: DPI effects were mimicked by veratridine, a Na+ channel agonist, and reversed by tetrodotoxin, yohimbine, and cadmium, Na+ channel antagonists. These results suggest that DPI acts primarily as a Na+ channel agonist. DPI may produce an increase in intracellular Ca2+ by increasing intracellular Na+ and altering Na+-Ca2+ exchange across the sarcolemma. DPI may also increase intracellular Ca2+ by directly altering sarcoplasmic reticulum Ca2+ handling.

Gwathmey, J K; Slawsky, M T; Briggs, G M; Morgan, J P

1988-01-01

397

Calcium Oscillations  

PubMed Central

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

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

2011-01-01

398

Novel hydrated brittle mica: Synthesis, characterization and cation exchange selectivity  

Microsoft Academic Search

Na-4-mica, a novel hydrated brittle mica with theoretical chemical formula of Nasb4Sisb4Alsb4Mgsb6Osb2OFsb4. XHsb2O, with a layer charge of -4 per unit cell, and with an unusually high number (four) of interlayer sodium ions was synthesized from metakaolinite + MgO and magnesium aluminosilicate gel powder at different temperatures and durations in a sodium fluoride melt. Highly crystalline and phase pure Na-4-mica

Rajyalakshmi Pidugu

1998-01-01

399

Sodium Phenylacetate and Sodium Benzoate  

Center for Drug Evaluation (CDER)

... Sodium Phenylacetate and Sodium Benzoate, Gastroenterology, UCD (NAGS; CPS; ASS; OTC; ASL; ARG), Indications and Usage Description ... More results from www.fda.gov/drugs/scienceresearch/researchareas

400

Preparation of calcium silicate absorbent from recycled glass  

Microsoft Academic Search

Calcium silicate hydrates were prepared from hydrated lime and post-consumer recycled glass in an aqueous slurry. These high surface area solids have shown promise as alkaline sorbents for environmental gas cleaning applications. Surface area was monitored at a variety of reaction conditions. The rate of surface area formation was found to be directly proportional to the initial surface area of

Lia F. Arthur; Gary T. Rochelle

1998-01-01

401

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

SciTech Connect

Using solution-state NMR spectroscopy, new insights into the early intermolecular interactions stabilizing amelogenin supramolecular assembly and the potential role of calcium ions have been discovered. Two-dimensional 1H-15N spectra were recorded for 15N-labeled amelogenin as a function of increasing Ca2+ concentration starting from monomeric conditions. Evidence for protein-protein interactions were observed between residues E18 and E40 in the N-terminus. At higher Ca2+ concentrations there was concurrent involvement of residues in both the N- (Y12-Q56) and the C-terminus (Q144-T171). Neither specific residues nor their stepwise interaction have previously been identified in the initial stages of nanosphere assembly.

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

2008-12-08

402

Decontamination of sodium cyanide  

Microsoft Academic Search

Small?scale DecontaminationAqueous sodium cyanide, buffered with ammonium chloride, was decontaminated by portionwise addition of calcium hypochlorite while the temperature of the mixture was held below 12C.Large?scale DecontaminationThe cyanide waste pH is raised to 10.0 and hypochlorite from any source used to convert cyanide to cyanate or even carbon dioxide and nitrogen if desired.

D. E. Pearson; T. M. Laher; S. Campagna

1981-01-01

403

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 ...

404

Adsorption of Gemini surfactants onto clathrate hydrates.  

PubMed

This work addresses the adsorption of two Gemini surfactants at the cyclopentane (CP) hydrate-water interface. The Gemini surfactants investigated here are Dowfax C6L and Dowfax 2A1 that have two anionic head groups and one hydrophobic tail group. The adsorption of these surfactants was quantified using adsorption isotherms and the adsorption isotherms were determined using liquid-liquid titrations. Even if the Gemini surfactant adsorption isotherms show multi-layer adsorption, they possess the first Langmuir layer with the second adsorption layer only evident in the 2A1 adsorption isotherm. Zeta potentials of CP hydrate particles in the surfactant solution of various concentrations of Dowfax C6L and Dowfax 2A1 were measured to further explain their adsorption behavior at the CP hydrate-water interface. Zeta potentials of alumina particles as a model particle system in different concentrations of sodium dodecyl sulfate (SDS), Dowfax C6L and Dowfax 2A1 were also measured to confirm the configuration of all the surfactants at the interface. The determination of the isotherms and zeta-potentials provides an understanding framework for the adsorption behavior of the two Gemini surfactants at the hydrate-water interface. PMID:24144366

Salako, O; Lo, C; Couzis, A; Somasundaran, P; Lee, J W

2013-09-17

405

Self-diffusion of sodium ions in compacted sodium montmorillonite  

SciTech Connect

Diffusion of sodium ions through compacted sodium montmorillonite in a water-saturated state was studied to obtain fundamental information for performance assessments of geological disposal of high-level radioactive waste. Basal spacings obtained from X-ray diffraction measurements indicated a decrease in the interlamellar spacing with increasing dry density of the montmorillonite; the three-water-layer hydrate was observed at low dry density, and the two-water-layer hydrate was observed at high dry density, whereas both were observed at dry densities between 1.4 and 1.5 Mg/m{sup 3}. Activation energies from 14.1 to 24.7 kJ/mol were obtained from the temperature dependence of the self-diffusion coefficients of sodium ions. Activation energies lower than that for the diffusion of sodium ions in free water were found for montmorillonite specimens with dry densities of {le} 1.2 Mg/m{sup 3}, while higher activation energies were observed at dry densities {ge} 1.4 Mg/m{sup 3}. The pore water diffusion model, the general model used for migration of nuclides, is based on geometric parameters; however, findings cannot be explained by only the changes in the geometric parameters. Possible explanations for the dry density dependence of the activation energy are changes in the temperature dependence of the distribution coefficients of sodium ions on the montmorillonite, changes in the diffusion process with an increase in dry density, or both.

Kozaki, Tamotsu; Fujishima, Atsushi; Sato, Seichi; Ohashi, Hiroshi [Hokkaido Univ., Sapporo (Japan)

1998-01-01

406

Hydrate adhesive and tensile strengths  

NASA Astrophysics Data System (ADS)

The physical properties of hydrate-bearing sediments depend on the interaction between hydrates and minerals. In particular, hydrates prefer to nucleate on mineral surfaces, therefore, the hydrate-mineral adhesive strength and the tensile strength of the hydrate mass itself affect the mechanical response of hydrate-bearing sediments. In this study, ice and hydrates made with various guest molecules (CO2, CH4, and THF) are formed between mica and calcite substrates. Adhesive and tensile strengths are measured by applying an external pull-out force. Results show that tensile failure occurs in CO2 and CH4 hydrates when calcite is the substrate, while ice and all hydrates exhibit adhesive failure on mica. The debonding strength is higher when calcite substrates are involved rather than mica substrates. A nominal pull-out strength of 0.15 0.03 MPa can be adopted for mechanical analyses of hydrate-bearing sediments.

Jung, J. W.; Santamarina, J. Carlos

2011-08-01

407

Ion Effects on Calcium Accumulation by Cardiac Sarcoplasmic Reticulum  

PubMed Central

The effects of monovalent cations on the active calcium-accumulating ability of cardiac sarcoplasmic reticulum were assessed. Grana prepared in an ion-free system accumulated calcium when ATP and Mg++ were present. Sodium ion and to a lesser extent lithium but not K+ reduced the amount of calcium taken up. The reduction of calcium binding by Na+ is not due to inhibition of uptake but to a rapid release of the radiocalcium bound. The amount of calcium released by sodium does not appear to be enough to explain contraction on the basis of sodium influx into muscle, but may be significant in the regulation of tension.

Palmer, Roger F.; Posey, Virginia A.

1967-01-01

408

Hydration testing of athletes.  

PubMed

Dehydration not only reduces athletic performance, but also places athletes at risk of health problems and even death. For athletes, monitoring hydration has significant value in maximising performance during training and competition. It also offers medical personnel the opportunity to reduce health risks in situations where athletes engage in intentional weight loss. Simple non-invasive techniques, including weight monitoring and urine tests, can provide useful information. Bioimpedance methods tend to be easy to use and fairly inexpensive, but generally lack the precision and accuracy necessary for hydration monitoring. Blood tests appear to be the most accurate monitoring method, but are impractical because of cost and invasiveness. Although future research is needed to determine which hydration tests are the most accurate, we encourage sports teams to develop and implement hydration monitoring protocols based on the currently available methods. Medical personnel can use this information to maximise their team's athletic performance and minimise heat- and dehydration-related health risks to athletes. PMID:12457417

Oppliger, Robert A; Bartok, Cynthia

2002-01-01

409

Transformations in methane hydrates  

USGS Publications Warehouse

Detailed study of pure methane hydrate in a diamond cell with in situ optical, Raman, and x-ray microprobe techniques reveals two previously unknown structures, structure II and structure H, at high pressures. The structure II methane hydrate at 250 MPa has a cubic unit cell of a = 17.158(2) A?? and volume V = 5051.3(13) A??3; structure H at 600 MPa has a hexagonal unit cell of a = 11.980(2) A??, c = 9.992(3) A??, and V = 1241.9(5) A??3. The compositions of these two investigated phases are still not known. With the effects of pressure and the presence of other gases in the structure, the structure II phase is likely to dominate over the known structure I methane hydrate within deep hydrate-bearing sediments underlying continental margins.

Chou, I. -M.; Sharma, A.; Burruss, R. C.; Shu, J.; Mao, H. -K.; Hemley, R. J.; Goncharov, A. F.; Stern, L. A.; Kirby, S. H.

2000-01-01

410

CALCIUM BINDING TO INTESTINAL MEMBRANES  

PubMed Central

Flame photometry reveals that glutaraldehyde and buffer solutions in routine use for electron microscopy contain varying amounts of calcium. The presence of electron-opaque deposits adjacent to membranes in a variety of tissues can be correlated with the presence of calcium in the fixative. In insect intestine (midgut), deposits occur adjacent to apical and lateral plasma membranes. The deposits are particularly evident in tissues fixed in glutaraldehyde without postosmication. They are also observed in osmicated tissue if calcium is added to wash and osmium solutions. Deposits are absent when calcium-free fixatives are used, but are present when traces of CaCl2 (as low as 5 x 10-5 M) are added. The deposits occur at regular intervals along junctional membranes, providing images strikingly similar to those obtained by other workers who have used pyroantimonate in an effort to localize sodium. Other divalent cations (Mg++, Sr++, Ba++, Mn++, Fe++) appear to substitute for calcium, while sodium, potassium, lanthanum, and mercury do not. After postfixing with osmium with calcium added, the deposits can be resolved as patches along the inner leaflet of apical and lateral plasma membranes. The dense regions may thus localize membrane constituents that bind calcium. The results are discussed in relation to the role of calcium in control of cell-to-cell communication, intestinal calcium uptake, and the pyroantimonate technique for ion localization.

Oschman, James L.; Wall, Betty J.

1972-01-01

411

Calcium transport in turtle bladder  

SciTech Connect

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

Sabatini, S.; Kurtzman, N.A. (Texas Tech Univ. Health Sciences Center, Lubbock (USA))

1987-12-01

412

Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange  

SciTech Connect

The enrichment of calcium isotopes has been observed in ion-exchange chromatography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occuring at the front of the band. Single-stage separation coefficients were found to be epsilon(/sup 44/Ca//sup 40/Ca) = 11 x 10 /sup -4/ and epsilon(/sup 48/Ca//sup 40/Ca) = 18 x 10/sup -4/. The maximum column separation factors achieved were 1.05 for calcium-44 and 1.09 for calcium-48 with the heavy isotopes enriching in the fluid phase. The calcium isotope effect between fully hydrated aqueous calcium ions and undissociated aqueous calcium hydroxide was estimated. For the calcium-44/40 isotope pair the separation coefficient was 13 x 10/sup -4/. 20 references, 2 figures.

Jepson, B.E.; Shockey, G.C.

1984-01-01

413

Determination of calcium, copper, iron, magnesium, manganese, potassium, phosphorus, sodium, and zinc in fortified food products by microwave digestion and inductively coupled plasma-optical emission spectrometry: single-laboratory validation and ring trial.  

PubMed

A single-laboratory validation (SLV) and a ring trial (RT) were undertaken to determine nine nutritional elements in food products by inductively coupled plasma-optical emission spectrometry in order to modernize AOAC Official Method 984.27. The improvements involved extension of the scope to all food matrixes (including infant formula), optimized microwave digestion, selected analytical lines, internal standardization, and ion buffering. Simultaneous determination of nine elements (calcium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, and zinc) was made in food products. Sample digestion was performed through wet digestion of food samples by microwave technology with either closed- or open-vessel systems. Validation was performed to characterize the method for selectivity, sensitivity, linearity, accuracy, precision, recovery, ruggedness, and uncertainty. The robustness and efficiency of this method was proven through a successful RT using experienced independent food industry laboratories. Performance characteristics are reported for 13 certified and in-house reference materials, populating the AOAC triangle food sectors, which fulfilled AOAC criteria and recommendations for accuracy (trueness, recovery, and z-scores) and precision (repeatability and reproducibility RSD, and HorRat values) regarding SLVs and RTs. This multielemental method is cost-efficient, time-saving, accurate, and fit-for-purpose according to ISO 17025 Norm and AOAC acceptability criteria, and is proposed as an extended updated version of AOAC Official Method 984.27 for fortified food products, including infant formula. PMID:22468357

Poitevin, Eric

414

The efflux of potassium, sodium, chloride, calcium and sulphate ions and of sorbitol and glycerol during the cardiac cycle in frog's ventricle  

PubMed Central

1. The exchanges of potassium and various other substances have been measured in beating frog's ventricles, using both superfused and distended preparations. In both preparations the high fluid flow rates used (1 ml./sec) cleared the ventricular cavity with a half-time (T) of about 130 msec. 2. Histological sections show that the modal strand radius in the relaxed or contracted distended ventricle is 175 ?, and in the relaxed and contracted superfused ventricle is 175 and 275 ? respectively. 3. In quiescent ventricles the resting potassium influx and efflux are approximately equal at about 16 p-mole/cm2.sec. This figure is computed from Niedergerke's (1963b) estimate of a cell size of 35 ? taken from electron-micrographs. If the older figure of 92 ? from single isolated cells is used (Skramlik, 1921) then the fluxes are about 44 p-mole/cm2.sec. To allow for some cell damage in these preparations a further increase in flux of about 30% may be necessary. 4. Contraction leads to a diminution of both potassium influx and efflux. Measurements made at 100 msec intervals throughout the cardiac cycle have demonstrated (a) that this decreased K efflux occurs at the same time as the mechanical twitch, and (b) that the size of the decrease is dependent on the external calcium concentration. Other experiments show that a similar decrease can be obtained by inducing a contracture at a constant membrane potential. It is concluded that the decreased K efflux during contraction is due to mechanical distortion of the tissue. This leads to a further slowing of the K diffusion and allows considerable reabsorption of K to occur into the cells. 5. Efflux analysis suggests that normal K diffusion in the extracellular space may be about 1/10 of that in free solution. If this is correct the true membrane fluxes may be 5 those measured. 6. Phasic efflux measurements of Na, Ca, K, Cl, SO4, sorbitol and erythritol show that a peak of efflux occurs just after the point of maximum rate of contraction of the ventricle. The peak efflux of K is least but all the other substances show similar patterns. In calcium-free solutions these phasic changes are absent. It is concluded that these effects are mechanical. 7. Net K and Na changes were measured in ventricles poisoned by ouabain. The computed net changes for quiescent ventricles were a gain of 28 p-mole/cm2.sec of Na and a loss of 53 p-mole/cm2.sec of K. On stimulation a further increase in Na uptake of 8 p-mole/cm2 occurred with no further loss of potassium. These results are computed for a cell diameter of 35 ?, for the larger diameter of 92 ? appropriate values of Na and K are 74 and 134 p-mole/cm2.sec respectively for quiescent ventricles and an extra Na uptake of 21 p-mole/cm2 per action potential. These results: (a) show that no large degree of single-file interaction occurs on the K movements, (b) are in agreement with the hypothesis that the membrane K fluxes are underestimated and (c) show that sufficient Na enters the cells per action potential to discharge a capacity of about 4 ?F/cm2. 8. A general conclusion reached in these experiments is that ion movements during the long cardiac action potential cannot easily be measured because of mechanical artifacts.

Lamb, J. F.; McGuigan, J. A. S.

1968-01-01

415

Ultrafine calcium aerosol: Generation and use of a sorbent for sulfur in coal combustion. Volume 2, Economics: Final report, August 1, 1988--October 31, 1991  

SciTech Connect

The goal of this study is to determine the cost effectiveness of using calcium-hydroxide powder sorbent in a commercial power plant flue gas desulfurization (FGD) application. The cost analysis methodology found herein is a direct application of the one found in the January 1986 report, ``Economic Evaluation of Dry-Injection Flue Gas Desulfurization Technology by the Electric Power Research Institute (EPRI). The EPRI study addresses the economic issue of installing a dry-injection FGD system on a 1000 MW (2-500 MW units) power plant using sodium-rich powder sorbents derived from nahcolite and trona ores. In this report`s treatment, the calcium-based derivatives of hydrated limestone are compared directly to nahcolite and trona for both low and high sulfur coals. This type of evaluation is allowable due to the similar material handling properties of 1/4 inch hydrated limestone in comparison to those properties for nahcolite and trona. Thus, this report repeats the EPRI cost analysis for a slightly modified limestone-based FGD design. Note that the calculation methodology is not discussed, in this report as it has already been outlined in the EPRI study. Instead, Appendices A and B contain copies of the calculation spreadsheets based on the EPRI method for the hydrated limestone system.

Alam, M.K.; Nahar, N.U.; Stewart, G.D.; Prudich, M.E. [comps.] [Ohio Coal Research Center, Athens, OH (United States)

1991-11-01

416

Sodium-dependent phosphate uptake in the jejunum is post-transcriptionally regulated in pigs fed a low-phosphorus diet and is independent of dietary calcium concentration.  

PubMed

In rodents, severe dietary P restriction increases active phosphate absorption by the intestine. However, it remains unknown if moderate dietary P restriction has a similar effect. Weanling pigs (n = 32; body weight 7.4 +/- 0.55 kg) were used in a 2 x 2 factorial design and fed dietary available P (aP) concentrations of 0.23 or 0.40% and Ca concentrations of 0.58 or 1.00% for 14 d. Diets were formulated on an aP basis instead of a total P basis, because pigs are unable to absorb phytate-P present in corn and soybean meal. Jejunal segments were mounted in modified Ussing chambers for determination of Na(+)-dependent nutrient transport. Intestinal mucosal scrapings were taken for RNA isolation and brush border membrane (BBM) vesicle isolation. Na(+)-dependent phosphate uptake and gene expression of Na-phosphate cotransporter IIb (NaPi-IIb), SGLT-1 (sodium/glucose cotransporter-1), and calbindin D(9k) and protein expression of NaPi-IIb were evaluated. Na(+)-dependent phosphate transport increased (P < 0.05) 46% as dietary aP concentration was decreased. However, increased Na(+)-dependent phosphate uptake was not accompanied by increased NaPi-IIb mRNA expression. Expression of NaPi-IIb protein in the BBM increased (P < 0.01) 84% in pigs fed low-P diets compared with pigs fed adequate-P diets. No dietary Ca effects or aP x Ca interactions were detected for Na-dependent P uptake, mRNA or protein expression of NaPi-IIb, or mRNA expression of calbindin D(9k). These data suggest that restricting dietary aP concentration by only 43% stimulates Na(+)-dependent phosphate uptake and expression of the NaPi-IIb protein in the BBM of the small intestine and through a post-transcriptional mechanism. PMID:20164365

Saddoris, Kari L; Fleet, James C; Radcliffe, John S

2010-02-17

417

Sodium - blood  

MedlinePLUS

... of diuretics, or burns Too much salt or sodium bicarbonate in your diet Use of certain medicines, including birth control pills, corticosteroids, laxatives, lithium, and NSAIDs ... normal sodium level is called hyponatremia. This may be due ...

418

Sodium Phosphate  

MedlinePLUS

Sodium phosphate is used to empty the colon (large intestine, bowel) before a colonoscopy (examination of the ... clear view of the walls of the colon. Sodium phosphate is in a class of medications called ...

419

Sodium Azide  

MedlinePLUS

... exposed to sodium azide, you should remove your clothing, rapidly wash your entire body with soap and ... medical care as quickly as possible. Removing your clothing: Quickly take off clothing that may have sodium ...

420

Conceptual HALT (Hydrate Addition at Low Temperature) scaleup design: Capital and operating costs: Part 5. [Hydrate addition at low temperature for the removal of SO  

Microsoft Academic Search

Hydrate addition at low temperature (or the HALT process) is a retrofit option for moderate SO removal efficiency in coal burning utility plants. This dry FGD process involves injecting calcium based dry hydrate particles into flue gas ducting downstream of the air preheater where the flue gas temperature is typically in the range of 280-325\\/degree\\/F. This report is comprised of

M. Babu; D. Kerivan; C. Hendrick; B. Kosek; D. Tackett; M. Golightley

1988-01-01

421

21 CFR 201.64 - Sodium labeling.  

Code of Federal Regulations, 2013 CFR

...you have [in bold type] [bullet] 1 a sodium-restricted diet. The warnings in §§ 201.64(c), 201.70(c...in alphabetical order, e g., a calcium or sodium restricted diet. 1 See § 201 .66(b)(4) of this chapter for...

2013-04-01

422

Compressibility of gas hydrates.  

PubMed

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 (3) , B(0)=11.2 GPa; for xenon hydrate V(0)=1726 (3) , B(0)=9.3 GPa; for the double hydrate of tetrahydrofuran+xenon V(0)=5323 (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 (92) 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

Manakov, Andrey Yu; Likhacheva, Anna Yu; Potemkin, Vladimir A; Ogienko, Andrey G; Kurnosov, Alexander V; Ancharov, Aleksei I

2011-06-29

423

Hydration of black carbon  

NASA Astrophysics Data System (ADS)

Hydration studies of n-hexane soot particles in the relative H2O pressure range 0.33-0.52 have revealed the nature of the processes between water molecules in the vapor phase and primary reaction sites at the particle surface. Initially, about 40% of the carbon-oxygen functionalities (most likely the carboxylics) on freshly prepared soot reacts irreversibly with water vapor, while at P/Po ? 0.48, the adsorption follows the Dubinin-Radushkevich equation. Determination of these parameters enables calculation of surface coverage at limiting adsorption and at the chemisorption limit for all materials studied. Limiting surface coverage of fresh soot is consistent with a 50% oxygen coverage determined earlier; it increases to about 100% for nitrated soot, which is the most extensively hydrated. Hydration has been shown to increase with soot aging, a phenomenon which has revealed an important role of physisorbed O2 in hydration. Trace-metal incorporation at the 30-110 ppm level significantly increases particle hydration and demonstrates a role of metal centers in the process.

Chughtai, A. R.; Brooks, M. E.; Smith, D. M.

1996-08-01

424

Raman spectroscopic determination of hydration number of methane hydrates  

Microsoft Academic Search

Hydration numbers of methane hydrates with various water\\/gas ratios of sample were measured by Raman spectroscopy. Artificial methane hydrates were formed at temperatures ranging from 273.2 to 278.4 K, and pressures from 3.0 to 7.0 MPa, with a stirring rate of approximately 500 rpm. Under such nonequilibrium conditions, the obtained hydrate samples had a water\\/gas ratio ranging from 6.4 to

Tsutomu Uchida; Takashi Hirano; Takao Ebinuma; Hideo Narita; Kazutoshi Gohara; Shinji Mae; Ryo Matsumoto

1999-01-01

425

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

SciTech Connect

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.

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

426

Drilling Gas Hydrates on hydrate Ridge, Oregon continental margin  

Microsoft Academic Search

During Leg 204, we cored and logged 9 sites on the Oregon continental margin to determine the distribution and concentration of gas hydrates in an accretionary ridge and adjacent slope basin, investigate the mechanisms that transport methane and other gases into the gas hydrate stability zone (GHSZ), and obtain constraints on physical properties of hydrates in situ. A 3D seismic

A. M. Trehu; G. Bohrmann

2002-01-01

427

Sea floor methane hydrates at Hydrate Ridge, Cascadia margin  

NASA Astrophysics Data System (ADS)

The crest of Hydrate Ridge harbors a variety of gas hydrates in near-surface sediments. Hydrate formation and destruction continuously shape the ridge topography. Interstitial Cl-anomaly patterns in conjunction with video-guided sampling have established that the uppermost sediment column contains several distinct layers of gas hydrate which are exposed at the sea floor. A methane-oxidizing bacterial consortium populates the exposures of hydrate; colonies of vent macro-fauna are abundant as well. Discharge of methane from destabilized hydrate at the seafloor stimulates high rates of benthic oxygen consumption. These rates, however, vary by many orders of magnitude spatially and temporally, highlighting the need for implementing seafloor observatories at gas hydrate sites. Two types of hydrate fabrics were observed: A highly porous fabric with an estimated pore space of approx. 60 vol.-% and a massive type, with no visible pore space. Both types contain varying amounts of chloride, which need to be taken into account when estimating hydrate volumes from Cl-depletion of pore waters. The porous hydrate has low bulk density, which may cause periodic release of large chunks of hydrate from the sea floor. They float to the surface and leave behind a chaotic topography of mounds and depressions. These pieces of floating hydrates constitute an important transport mechanism for methane from the seafloor directly to the atmosphere.

Suess, E.; Torres, M. E.; Bohrmann, G.; Collier, R. W.; Rickert, D.; Goldfinger, C.; Linke, P.; Heuser, A.; Sahling, H.; Heeschen, K.; Jung, C.; Nakamura, K.; Greinert, J.; Pfannkuche, O.; Trehu, A.; Klinkhammer, G.; Whiticar, M. J.; Eisenhauer, A.; Teichert, B.; Elver, M.

428

HYDRATE CORE DRILLING TESTS  

SciTech Connect

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.

John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

2002-11-01

429

Kinetic behaviors of CO 2 hydrates in porous media and effect of kinetic promoter on the formation kinetics  

Microsoft Academic Search

Formation behaviors of CO2 hydrate in silica gels are investigated at various pressure and temperature conditions. In addition, a kinetic promoter of sodium dodecyl sulfate (SDS) is used in order to evaluate promotional effect on the formation behaviors in porous media. Formation rates and hydrate conversions are found to be large when higher pressure or lower temperature is used at

Seong-Pil Kang; Jong-Won Lee

2010-01-01

430

Adhesion of Hydrated Silicate Films.  

National Technical Information Service (NTIS)

We used fracture mechanics test techniques to measure the adhesive bond energy formed between hydrated silica glass surfaces and silicate species deposited from solution. In the case of silicate surfaces hydrated in room temperature water vapor, intermole...

T. A. Michalske K. D. Keefer

1988-01-01

431

Hydration of highly charged ions  

NASA Astrophysics Data System (ADS)

Concise treatment of highly charged ions with very different properties. Performed by ab initio simulations with the recent QMCF-MD methodology. Treating hydrates with extreme stability, labile hydrates and instable systems with (sub-)picosecond proton transfer reactions.

Hofer, Thomas S.; Weiss, Alexander K. H.; Randolf, Bernhard R.; Rode, Bernd M.

2011-08-01

432

Gas Hydrates: It's A Gas!  

NSDL National Science Digital Library

In this activity, students will investigate the occurrence of gas hydrates on the ocean floor. They will discover the importance of carbon, where carbon is stored on Earth, and that the largest reservoir of carbon is gas hydrates. Students will discover that Earth's climate changes, and how the greenhouse effect works. They will also learn about the potential of hydrates as a major new energy resource and explore the conditions under which hydrates form.

433

Improved evidence for the existence of an intermediate phase during hydration of tricalcium silicate  

SciTech Connect

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.

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

434

Calcium aluminosilicate glass corrosion by phosphoric acid  

Microsoft Academic Search

The corrosion rates of a series of calcium aluminosilicate and sodium calcium aluminosilicate glasses were determined in three phosphoric acids at several temperatures. The effect of temperature on corrosion rate was determined for one glass in 30 wt % HPO; an activation energy was determined as well. The glasses are virtually insoluble at silica concentrations of >55 wt % SiO

N. C. Thakore; T. J. Rockett

1980-01-01

435

Aluminum Sulfate 18 Hydrate  

ERIC Educational Resources Information Center

|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.|

Young, Jay A.

2004-01-01

436

[Hydration in clinical practice].  

PubMed

Water is an essential foundation for life, having both a regulatory and structural function. The former results from active and passive participation in all metabolic reactions, and its role in conserving and maintaining body temperature. Structurally speaking it is the major contributer to tissue mass, accounting for 60% of the basis of blood plasma, intracellular and intersticial fluid. Water is also part of the primary structures of life such as genetic material or proteins. Therefore, it is necessary that the nurse makes an early assessment of patients water needs to detect if there are signs of electrolyte imbalance. Dehydration can be a very serious problem, especially in children and the elderly. Dehydrations treatment with oral rehydration solution decreases the risk of developing hydration disorders, but even so, it is recommended to follow preventive measures to reduce the incidence and severity of dehydration. The key to having a proper hydration is prevention. Artificial nutrition encompasses the need for precise calculation of water needs in enteral nutrition as parenteral, so the nurse should be part of this process and use the tools for calculating the patient's requirements. All this helps to ensure an optimal nutritional status in patients at risk. Ethical dilemmas are becoming increasingly common in clinical practice. On the subject of artificial nutrition and hydration, there isn't yet any unanimous agreement regarding hydration as a basic care. It is necessary to take decisions in consensus with the health team, always thinking of the best interests of the patient. PMID:21428011

Maristany, Cleof Prez-Portabella; Segurola Gurruchaga, Hegoi

2011-01-01

437

Desalination Through Methane Hydrate.  

National Technical Information Service (NTIS)

In one embodiment, this invention pertains to desalination of seawater by feeding methane into seawater at a depth exceeding 100 meters to form methane hydrate which rises to where it is decomposed into methane and water, and recovering water. Methane is ...

M. D. Max R. E. Pellenbarg

1997-01-01

438

Aluminum Sulfate 18 Hydrate  

ERIC Educational Resources Information Center

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.

Young, Jay A.

2004-01-01