Sodium Hydroxide and Calcium Hydroxide Hybrid Oxygen Bleaching with System

Science.gov (United States)

Doelle, K.; Bajrami, B.

2018-01-01

This study investigates the replacement of sodium hydroxide in the oxygen bleaching stage using a hybrid system consisting of sodium hydroxide calcium hydroxide. Commercial Kraft pulping was studied using yellow pine Kraft pulp obtained from a company in the US. The impact of sodium hydroxide, calcium hydroxide hybrid system in regard to concentration, reaction time and temperature for Kraft pulp was evaluated. The sodium hydroxide and calcium hydroxide dosage was varied between 0% and 15% based on oven dry fiber content. The bleaching reaction time was varied between 0 and 180 minutes whereas the bleaching temperature ranged between 70 °C and 110 °C. The ability to bleach pulp was measured by determining the Kappa number. Optimum bleaching results for the hybrid system were achieved with 4% sodium hydroxide and 2% calcium hydroxide content. Beyond this, the ability to bleach pulp decreased.

Calcification mechanism and bony bonding studies of calcium carbonate and composite aluminosilicate/calcium phosphate applied as biomaterials by using radioactivation methods

International Nuclear Information System (INIS)

Oudadesse, H.; Derrien, A.C.; Lucas-Girot, A.; Martin, S.; Cathelieau, G.

2007-01-01

Bony grafts are used as a filling biomaterial for defective bone. The introduction of new range of synthetic materials offers to surgeons additional possibilities to avoid virus transmission risks by using natural grafts in bony surgery. In this work, two materials, synthetic calcium carbonate and composite aluminosilicate/calcium phosphate were synthesized by an original method and experimented 'in vivo' as biomaterials for bony filling. Extracted biopsies were studied by several physico chemical and biological methods. The aim was to evaluate the kinetic resorption and bioconsolidation of these materials. We focused on the bioconsolidation between implant and bone by realising cartographies from the implant to the bone and on the calcification mechanism by determination of the origin of Ca and Sr responsible of the neo-formed bone. Neutron activation analysis (NAA), radiotracers 45 Ca* and 85 Sr* and proton-induced X-ray emission (PIXE) were used. Concerning the synthetic calcium carbonate, results show that twelve months after implantation, the mineral composition of implant becomes similar to that of the mature bone. The neoformed bone is composed with Ca and Sr coming from the organism when the Ca and Sr of the implant were progressively eliminated. Concerning the composite geopolymer/calcium phosphate, PIXE and histological studies reveal the intimate links between the bone and the implant starting with the first month after implantation. (author)

In situ structural analysis of calcium aluminosilicate glasses under high pressure.

Science.gov (United States)

Muniz, R F; de Ligny, D; Martinet, C; Sandrini, M; Medina, A N; Rohling, J H; Baesso, M L; Lima, S M; Andrade, L H C; Guyot, Y

2016-08-10

In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH(-)-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ([Formula: see text][T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q (n) species to Q (n-1). In the case of Al-rich glass, the Al in the smallest Q (n) units evolved from tetrahedral to higher-coordinated Al (([5])Al and ([6])Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

Emission tunability and local environment in europium-doped OH{sup −}-free calcium aluminosilicate glasses for artificial lighting applications

Energy Technology Data Exchange (ETDEWEB)

Farias, Aline M.; Sandrini, Marcelo; Viana, José Renato M.; Baesso, Mauro L.; Bento, Antônio C.; Rohling, Jurandir H. [Departamento de Física, Universidade Estadual de Maringá, Av Colombo, 5790, 87020-900, Maringá, PR (Brazil); Guyot, Yannick [Laboratoire de Physico–Chimie des Matériaux Luminescents, Université de Lyon, Université Claude Bernard Lyon 1, Villeurbanne, UMR 5620 CNRS 69622 (France); De Ligny, Dominique [Department of Materials Science and Engineering, University of Erlangen Nürnberg, Martens str. 5, 91058, Erlangen (Germany); Nunes, Luiz Antônio O. [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador São-Carlense400, 13566-590, São Carlos, SP (Brazil); Gandra, Flávio G. [Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859, Campinas, SP (Brazil); Sampaio, Juraci A. [Lab Ciências Físicas, Universidade Estadual Norte Fluminense, 28013-602, Campos Dos Goytacazes, RJ (Brazil); Lima, Sandro M.; Andrade, Luis Humberto C. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul-UEMS, Dourados, MS, C. P. 351, CEP 79804-970 (Brazil); and others

2015-04-15

The relationship between emission tunability and the local environment of europium ions in OH{sup −}-free calcium aluminosilicate glasses was investigated, focusing on the development of devices for artificial lighting. Significant conversion of Eu{sup 3+} to Eu{sup 2+} was obtained by means of melting the glasses under a vacuum atmosphere and controlling the silica content, resulting in broad, intense, and tunable luminescence ranging from blue to red. Electron spin resonance and X-ray absorption near edge structure measurements enabled correlation of the luminescence behavior of the material with the Eu{sup 2+}/Eu{sup 3+} concentration ratio and changes in the surrounding ions' crystal field. The coordinates of the CIE 1931 chromaticity diagram were calculated from the spectra, and the contour maps showed that the light emitted from Eu{sup 2+} presented broad bands and enhanced color tuning, ranging from reddish-orange to blue. The results showed that these Eu doped glasses can be used for tunable white lighting by combining matrix composition and the adjustment of the pumping wavelength. - Highlights: • Eu{sup 2+}-doped OH{sup −} free calcium aluminosilicate glass as a new source for white lighting. • Correlation between emission tunability and local environment of europium ions. • Significant reduction of Eu{sup 3+} to Eu{sup 2+} by melting the glasses under vacuum atmosphere. • Broad, intense and tunable luminescence ranging from blue to red.

Modification of Lime Mortars with Synthesized Aluminosilicates

Science.gov (United States)

Loganina, Valentina I.; Sadovnikova, Marija E.; Jezierski, Walery; Małaszkiewicz, Dorota

2017-10-01

The increasing attention for restoration of buildings of historical and architectural importance has increased the interest for lime-based binders, which could be applied for manufacturing repair mortars and plasters compatible with historical heritage. Different additives, admixtures or fibers may be incorporated to improve mechanical and thermal features of such materials. In this study synthesized aluminosilicates (SA) were applied as an additive for lime mortar. The technology of synthesis consisted in the deposition of aluminosilicates from a sodium liquid glass by the aluminum sulphate Al2(SO4)3. The goal of this investigation was developing a new method of aluminosilicates synthesis from a sodium liquid glass and using this new material as a component for a lime mortar. Aluminosilicates were precipitated from the solution of aluminum sulphate Al2(SO)3 and sodium silicate. SA were then used as an additive to calcareous compositions and their influence was tested. Mortars were prepared with commercial air lime and siliceous river sand. Air lime binder was replaced by 5 and 10 wt.% of SA. Calcareous composition specimens were formed at water/lime ratio 1.0. The following analyses were made: grain size distribution of SA, X-ray diffraction analysis (XRD), sorption properties, plastic strength and compressive strength of lime mortars. XRD pattern of the SA shows the presence of thenardite, gibbsite and amorphous phase represented by aggregate of nano-size cristobalite-like crystallites. Application of SA leads to increase of compressive strength after 90 days of hardening by 28% and 53% at SA content 5 and 10% respectively comparing to specimens without this additive. Contents of chemically bound lime in the reference specimens after 28 days of hardening in air-dry conditions was 46.5%, while in specimens modified with SA contained 50.0-55.3% of bound lime depending on filtrate pH. This testifies to high activity of calcareous composition. The new blended lime

Striking role of non-bridging oxygen on glass transition temperature of calcium aluminosilicate glass-formers

International Nuclear Information System (INIS)

Bouhadja, M.; Jakse, N.; Pasturel, A.

2014-01-01

Molecular dynamics simulations are used to study the structural and dynamic properties of calcium aluminosilicate, (CaO-Al 2 O 3 ) 1−x (SiO 2 ) x , glass formers along three joins, namely, R = 1, 1.57, and 3, in which the silica content x can vary from 0 to 1. For all compositions, we determined the glass-transition temperature, the abundances of the non-bridging oxygen, triclusters, and AlO 5 structural units, as well as the fragility from the temperature evolution of the α-relaxation times. We clearly evidence the role played by the non-bridging oxygen linked either to Al atoms or Si atoms in the evolution of the glass-transition temperature as well as of the fragility as a function of silica content along the three joins

Molecular dynamics simulation of sodium aluminosilicate glass structures and glass surface-water reactions using the reactive force field (ReaxFF)

Science.gov (United States)

Dongol, R.; Wang, L.; Cormack, A. N.; Sundaram, S. K.

2018-05-01

Reactive potentials are increasingly used to study the properties of glasses and glass water reactions in a reactive molecular dynamics (MD) framework. In this study, we have simulated a ternary sodium aluminosilicate glass and investigated the initial stages of the glass surface-water reactions at 300 K using reactive force field (ReaxFF). On comparison of the simulated glass structures generated using ReaxFF and classical Buckingham potentials, our results show that the atomic density profiles calculated for the surface glass structures indicate a bond-angle distribution dependency. The atomic density profiles also show higher concentrations of non-bridging oxygens (NBOs) and sodium ions at the glass surface. Additionally, we present our results of formation of silanol species and the diffusion of water molecules at the glass surface using ReaxFF.

Crystal growth of calcium carbonate in silk fibroin/sodium alginate hydrogel

Science.gov (United States)

Ming, Jinfa; Zuo, Baoqi

2014-01-01

As known, silk fibroin-like protein plays a pivotal role during the formation of calcium carbonate (CaCO3) crystals in the nacre sheets. Here, we have prepared silk fibroin/sodium alginate nanofiber hydrogels to serve as templates for calcium carbonate mineralization. In this experiment, we report an interesting finding of calcium carbonate crystal growth in the silk fibroin/sodium alginate nanofiber hydrogels by the vapor diffusion method. The experimental results indicate calcium carbonate crystals obtained from nanofiber hydrogels with different proportions of silk fibroin/sodium alginate are mixture of calcite and vaterite with unusual morphologies. Time-dependent growth study was carried out to investigate the crystallization process. It is believed that nanofiber hydrogels play an important role in the process of crystallization. This study would help in understanding the function of organic polymers in natural mineralization, and provide a novel pathway in the design and synthesis of new materials related unique morphology and structure.

Codissolution of calcium hydrogenphosphate and sodium hydrogencitrate in water. Spontaneous supersaturation of calcium citrate increasing calcium bioavailability

DEFF Research Database (Denmark)

Hedegaard, Martina Vavrusova; Danielsen, Bente Pia; Garcia, André Castilho

2018-01-01

The sparingly soluble calcium hydrogenphosphate dihydrate, co-dissolving in water during dissolution of freely soluble sodium hydrogencitrate sesquihydrate as caused by proton transfer from hydrogencitrate to hydrogenphosphate, was found to form homogenous solutions supersaturated by a factor up...... to 8 in calcium citrate tetrahydrate. A critical hydrogencitrate concentration for formation of homogeneous solutions was found to depend linearly on dissolved calcium hydrogenphosphate: [HCitr2-] = 14[CaHPO4] - 0.05 at 25 °C. The lag phase for precipitation of calcium citrate tetrahydrate......, as identified from FT-IR spectra, from these spontaneously formed supersaturated solutions was several hours, and the time to reach solubility equilibrium was several days. Initial calcium ion activity was found to be almost independent of the degree of supersaturation as determined electrochemically...

Reactions between rocks and the hydroxides of calcium, sodium and potassium: progress report no. 1

International Nuclear Information System (INIS)

Van Aardt, J.H.P.; Visser, S.

1982-01-01

The reaction between the hydroxides of calcium, sodium and potassium, and clay minerals, feldspars, and some rocks (aggregates for use in concrete) was investigated. The reaction products were examined by means of x-ray diffraction and chemical analysis. The solid reaction products identified were hydrated calcium silicates,hydrated calcium aluminates, and hydrated calcium alumina silicates. It was found that, in the presence of water, calcium hydroxide liberated alkali into solution if the rocks and minerals contained alkali metals in their structure. Two crystalline hydrated sodium calcium silicates (12A and 16A) were prepared in the system Na 2 O-CaO-SiO 2 -H 2 O at 80 degrees Celsius. The one compound (12A) was also observed when sodium hydroxide plus calcium hydroxide and water reacted with silica- or silicate-containing rocks

Sodium-calcium ion exchange on clay minerals at moderate to high ionic strengths

International Nuclear Information System (INIS)

Rogers, W.J.

1979-12-01

Sodium-calcium ion exchange on several clay minerals was studied at ionic strengths ranging from 0.01 to above 1.0. The minerals studied included attapulgite, illite, kaolin, and several montmorillonites. Distribution coefficients of calcium and sodium were obtained for the minerals over a wide range of solution conditions at pH five and equilibrium constants were calculated. The distribution coefficient of calcium, D/sub Ca/, was studied as a function of time, solution pH, loading, sodium concentration, and ionic strength fraction of sodium in constant ionic strength solutions. The distribution coefficient of sodium, D/sub Na/, was also studied as a function of time, loading, and sodium ionic strength fraction in constant total ionic strength solutions. Values of equilibrium constants calculated from distribution coefficients for solutions of constant ionic strength scattered bwteen 2 and 10 kg/kg for the montmorillonites and attapulgite while equilibrium constants for illite ranged from 5 to 10 kg/kg. No equilibrium constants for kaolin were calculated since distribution coefficients of sodium on this clay were too small to be measured. It was found that equilibrium constants at trace sodium loading were generally lower than those for higher sodium loadings by an order of magnitude or more due to the sensitivity of sodium distribution coefficients to the concentration of sodium in the clay at low loadings. Theoretical and experimental treatments of ion exclusion were included

The effect of sodium bicarbonate upon urinary citrate excretion in calcium stone formers.

Science.gov (United States)

Pinheiro, Vivian Barbosa; Baxmann, Alessandra Calábria; Tiselius, Hans-Göran; Heilberg, Ita Pfeferman

2013-07-01

To evaluate the effects of oral sodium bicarbonate (NaBic) supplementation upon urinary citrate excretion in calcium stone formers (CSFs). Sixteen adult calcium stone formers with hypocitraturia were enrolled in a randomized, double-blind, crossover protocol using 60 mEq/day of NaBic during 3 days compared to the same period and doses of potassium citrate (KCit) supplementation. Blood and 24-hour urine samples were collected at baseline and during the third day of each alkali salt. NaBic, similarly to KCit supplementation, led to an equivalent and significant increase in urinary citrate and pH. Compared to baseline, NaBic led to a significant increase in sodium excretion without concomitant increases in urinary calcium excretion, whereas KCit induced a significant increase in potassium excretion coupled with a significant reduction in urinary calcium. Although NaBic and KCit both reduced calcium oxalate supersaturation (CaOxSS) significantly vs baseline, KCit reduced calcium oxalate supersaturation significantly further vs NaBic. Both KCit and NaBic significantly reduced urinary phosphate and increased calcium phosphate supersaturation (CaPSS) compared to baseline. Finally, a significantly higher sodium urate supersaturation (NaUrSS) was observed after the use of the 2 drugs. This short-term study suggests that NaBic represents an effective alternative for the treatment of hypocitraturic calcium oxalate stone formers who cannot tolerate or afford the cost of KCit. In view of the increased sodium urate supersaturation, patients with pure uric acid stones and high urate excretion may be less suited for treatment with NaBic. Copyright © 2013 Elsevier Inc. All rights reserved.

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

International Nuclear Information System (INIS)

Chase, H.S. Jr.; Al-Awqati, Q.

1983-01-01

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

Direct determination of calcium, sodium and potassium in fermented milk products

Directory of Open Access Journals (Sweden)

Kravić Snežana Ž.

2012-01-01

Full Text Available The aim of this study was the investigation of the possibilities of direct determination of calcium, sodium and potassium in the commercial and kombucha-based fermented milk products by flame photometry. Two procedures were used for sample preparation: simple dilution with water (direct method and extraction with mineral acid. Calcium, sodium and potassium levels determined after mentioned sample preparation methods were compared. The results showed that the differences between the values obtained for the different sample treatment were within the experimental error at the 95% confidence level. Compared to the method based on extraction with mineral acid, the direct method is efficient, faster, simpler, cheaper, and operates according to the principles of Green Chemistry. Consequently, the proposed method for the direct determination of calcium, sodium and potassium could be applied for the rapid routine analysis of the mineral content in the fermented dairy products. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

Contracture Coupling of Slow Striated Muscle in Non-Ionic Solutions and Replacement of Calcium, Sodium, and Potassium

Science.gov (United States)

Irwin, Richard L.; Hein, Manfred M.

1964-01-01

The development of contracture related to changes of ionic environment (ionic contracture coupling) has been studied in the slowly responding fibers of frog skeletal muscle. When deprived of external ions for 30 minutes by use of solutions of sucrose, mannitol, or glucose, the slow skeletal muscle fibers, but not the fast, develop pronounced and easily reversible contractures. Partial replacement of the non-ionic substance with calcium or sodium reduces the development of the contractures but replacement by potassium does not. The concentration of calcium necessary to prevent contracture induced by a non-ionic solution is greater than that needed to maintain relaxation in ionic solutions. To suppress the non-ionic-induced contractures to the same extent as does calcium requires several fold higher concentrations of sodium. Two types of ionic contracture coupling occur in slow type striated muscle fibers: (a) a calcium deprivation type which develops maximally at full physiological concentration of external sodium, shows a flow rate dependency for the calcium-depriving fluid, and is lessened when the sodium concentration is decreased by replacement with sucrose; (b) a sodium deprivation type which occurs maximally without external sodium, is lessened by increasing the sodium concentration, and has no flow rate dependency for ion deprivation. Both types of contracture are largely prevented by the presence of sufficient calcium. There thus seem to be calcium- and sodium-linked processes at work in the ionic contracture coupling of slow striated muscle. PMID:14127603

Intracellular calcium modulation of voltage-gated sodium channels in ventricular myocytes

NARCIS (Netherlands)

Casini, Simona; Verkerk, Arie O.; van Borren, Marcel M. G. J.; van Ginneken, Antoni C. G.; Veldkamp, Marieke W.; de Bakker, Jacques M. T.; Tan, Hanno L.

2009-01-01

AIMS: Cardiac voltage-gated sodium channels control action potential (AP) upstroke and cell excitability. Intracellular calcium (Ca(i)(2+)) regulates AP properties by modulating various ion channels. Whether Ca(i)(2+) modulates sodium channels in ventricular myocytes, is unresolved. We studied

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

Science.gov (United States)

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

1990-06-01

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).

An Empirical Model for Build-Up of Sodium and Calcium Ions in Small Scale Reverse Osmosis

Directory of Open Access Journals (Sweden)

Subriyer Nasir

2011-05-01

Full Text Available A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and reject streams using Atomic Absorption Spectrophotometer (AAS. Multiple linear regression of natural logarithmic transformation was used to develop the model based on four main parameters that affect the build-up of solute in a small scale of RO namely applied pressure, permeate flux, membrane resistance, and feed concentration. Experimental data obtained in a small scale RO unit were used to develop the empirical model. The predicted values of theoretical build-up of sodium and calcium on membrane surface were found in agreement with experimental data. The deviation in the prediction of build-up of sodium and calcium were found to be 1.4 to 10.47 % and 1.12 to 4.46%, respectively.

Energetics of discrete selectivity bands and mutation-induced transitions in the calcium-sodium ion channels family.

Science.gov (United States)

Kaufman, I; Luchinsky, D G; Tindjong, R; McClintock, P V E; Eisenberg, R S

2013-11-01

We use Brownian dynamics (BD) simulations to study the ionic conduction and valence selectivity of a generic electrostatic model of a biological ion channel as functions of the fixed charge Q(f) at its selectivity filter. We are thus able to reconcile the discrete calcium conduction bands recently revealed in our BD simulations, M0 (Q(f)=1e), M1 (3e), M2 (5e), with a set of sodium conduction bands L0 (0.5e), L1 (1.5e), thereby obtaining a completed pattern of conduction and selectivity bands vs Q(f) for the sodium-calcium channels family. An increase of Q(f) leads to an increase of calcium selectivity: L0 (sodium-selective, nonblocking channel) → M0 (nonselective channel) → L1 (sodium-selective channel with divalent block) → M1 (calcium-selective channel exhibiting the anomalous mole fraction effect). We create a consistent identification scheme where the L0 band is putatively identified with the eukaryotic sodium channel The scheme created is able to account for the experimentally observed mutation-induced transformations between nonselective channels, sodium-selective channels, and calcium-selective channels, which we interpret as transitions between different rows of the identification table. By considering the potential energy changes during permeation, we show explicitly that the multi-ion conduction bands of calcium and sodium channels arise as the result of resonant barrierless conduction. The pattern of periodic conduction bands is explained on the basis of sequential neutralization taking account of self-energy, as Q(f)(z,i)=ze(1/2+i), where i is the order of the band and z is the valence of the ion. Our results confirm the crucial influence of electrostatic interactions on conduction and on the Ca(2+)/Na(+) valence selectivity of calcium and sodium ion channels. The model and results could be also applicable to biomimetic nanopores with charged walls.

Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

International Nuclear Information System (INIS)

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

2007-01-01

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

Calcium-Magnesium-Aluminosilicate (CMAS) Reactions and Degradation Mechanisms of Advanced Environmental Barrier Coatings

Science.gov (United States)

Ahlborg, Nadia L.; Zhu, Dongming

2013-01-01

The thermochemical reactions between calcium-magnesium-aluminosilicate- (CMAS-) based road sand and several advanced turbine engine environmental barrier coating (EBC) materials were studied. The phase stability, reaction kinetics and degradation mechanisms of rare earth (RE)-silicates Yb2SiO5, Y2Si2O7, and RE-oxide doped HfO2 and ZrO2 under the CMAS infiltration condition at 1500 C were investigated, and the microstructure and phase characteristics of CMAS-EBC specimens were examined using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Experimental results showed that the CMAS dissolved RE-silicates to form crystalline, highly non-stoichiometric apatite phases, and in particular attacking the silicate grain boundaries. Cross-section images show that the CMAS reacted with specimens and deeply penetrated into the EBC grain boundaries and formed extensive low-melting eutectic phases, causing grain boundary recession with increasing testing time in the silicate materials. The preliminary results also showed that CMAS reactions also formed low melting grain boundary phases in the higher concentration RE-oxide doped HfO2 systems. The effect of the test temperature on CMAS reactions of the EBC materials will also be discussed. The faster diffusion exhibited by apatite and RE-doped oxide phases and the formation of extensive grain boundary low-melting phases may limit the CMAS resistance of some of the environmental barrier coatings at high temperatures.

Alginate-based pellets prepared by extrusion/spheronization: effect of the amount and type of sodium alginate and calcium salts.

Science.gov (United States)

Sriamornsak, Pornsak; Nunthanid, Jurairat; Luangtana-anan, Manee; Weerapol, Yossanun; Puttipipatkhachorn, Satit

2008-05-01

Pellets containing microcrystalline cellulose (MCC), a model drug (theophylline) and a range of levels of sodium alginate (i.e., 10-50% w/w) were prepared by extrusion/spheronization. Two types of sodium alginate were evaluated with and without the addition of either calcium acetate or calcium carbonate (0, 0.3, 3 and 10% w/w). The effects of amount and type of sodium alginate and calcium salts on pellet properties, e.g., size, shape, morphology and drug release behavior, were investigated. Most pellet formulations resulted in pellets of a sufficient quality with respect to size, size distribution and shape. The results showed that the amounts of sodium alginate and calcium salts influenced the size and shape of the obtained pellets. However, different types of sodium alginate and calcium salt responded to modifications to a different extent. A cavity was observed in the pellet structure, as seen in the scanning electron micrographs, resulting from the forces involved in the spheronization process. Most of pellet formulations released about 75-85% drug within 60 min. Incorporation of calcium salts in the pellet formulations altered the drug release, depending on the solubility of the calcium salts used. The drug release data showed a good fit into both Higuchi and Korsmeyer-Peppas equations.

Determinants of sodium and calcium adsorption onto neutral lipid bilayers

Czech Academy of Sciences Publication Activity Database

Javanainen, M.; Melcrová, Adéla; Magarkar, Aniket; Jurkiewicz, Piotr; Hof, Martin; Jungwirth, Pavel; Martinez-Seara, Hector

2017-01-01

Roč. 46, Suppl 1 (2017), S121 ISSN 0175-7571. [IUPAB congress /19./ and EBSA congress /11./. 16.07.2017-20.07.2017, Edinburgh] Institutional support: RVO:61388963 ; RVO:61388955 Keywords : sodium * calcium * lipid bilayer Subject RIV: BO - Biophysics

Aqueous dissolution of sodium aluminosilicate geopolymers derived from metakaolin

Energy Technology Data Exchange (ETDEWEB)

Aly, Z., E-mail: zaynab.aly@ansto.gov.au [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Vance, E.R. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia); Perera, D.S. [School of Materials Science, University of NSW, Kensington, NSW 2052 (Australia)

2012-05-15

Highlights: Black-Right-Pointing-Pointer In dilute solutions, Na, Al and Si releases were not sensitive to pH in range 4-10. Black-Right-Pointing-Pointer On heating from 18 to 90 Degree-Sign C in DIW, Na dissolution rate increased by a factor of {approx}4. Black-Right-Pointing-Pointer Elemental extractions in DIW at 18 Degree-Sign C increased linearly with time over 1-7 days. Black-Right-Pointing-Pointer Na release kinetics in DIW followed a pseudo-second-order kinetic model. Black-Right-Pointing-Pointer Contact with KCl, KHCO{sub 3} and phthalate buffers (pH6 and 10) resulted in Na{sup +} {r_reversible} K{sup +} exchange. - Abstract: In dilute aqueous solutions, the elemental releases of Na, Al and Si from a metakaolin-based sodium aluminosilicate geopolymer were not very sensitive to pH in the range of 4-10 but increased outside this range, particularly on the acidic side. To minimise pH drifts, experiments were carried out using small amounts of graded powders in relatively large volumes of water. In deionised water, the Na dissolution rate in 7 days was dominant and increased by at least a factor of {approx}4 on heating from 18 to 90 Degree-Sign C, with greater increases in the extractions of Al and Si. At 18 Degree-Sign C the elemental extractions in deionised water increased approximately linearly with time over the 1-7 days period. Further exposure led to a slower extraction into solution for Na and Si, with a decrease in extraction of Al. It was deduced that framework dissolution was important in significantly acidic or alkaline solutions, but that contributions from water transfer from pores to elemental extractions were present, even at low temperatures in neutral solutions. It was also deduced from the Na release data that the Na leaching kinetics of geopolymer in deionised water (dilute solutions) followed the pseudo-second-order kinetic model and the pseudo-second-order rate constant evaluated. Contact with KCl, KHCO{sub 3}, and pH {approx}6 and 10

Geographic distribution of soluble salts, exchangeable sodium and calcium carbonate in the Caribbean Region of Colombia

International Nuclear Information System (INIS)

Pulido, Carlos E

2000-01-01

A research was carried out to establish the distribution of soluble salts, exchangeable sodium and calcium carbonate in the soils of the Caribbean Region. The results show that 28,3% (3.506.033 ha) of the soils have problems related to salinity. The soils of the arid and semiarid zones and those belonging to the sea plain are affected severely by soluble salts, exchangeable sodium and calcium carbonate

Calcium-Magnesium-Aluminosilicate (CMAS) Infiltration and Cyclic Degradations of Thermal and Environmental Barrier Coatings in Thermal Gradients

Science.gov (United States)

Zhu, Dongming; Harder, Bryan; Smialek, Jim; Miller, Robert A.

2014-01-01

In a continuing effort to develop higher temperature capable turbine thermal barrier and environmental barrier coating systems, Calcium-Magnesium-Aluminosilicate (CMAS) resistance of the advanced coating systems needs to be evaluated and improved. This paper highlights some of NASA past high heat flux testing approaches for turbine thermal and environmental barrier coatings assessments in CMAS environments. One of our current emphases has been focused on the thermal barrier - environmental barrier coating composition and testing developments. The effort has included the CMAS infiltrations in high temperature and high heat flux turbine engine like conditions using advanced laser high heat flux rigs, and subsequently degradation studies in laser heat flux thermal gradient cyclic and isothermal furnace cyclic testing conditions. These heat flux CMAS infiltration and related coating durability testing are essential where appropriate CMAS melting, infiltration and coating-substrate temperature exposure temperature controls can be achieved, thus helping quantify the CMAS-coating interaction and degradation mechanisms. The CMAS work is also playing a critical role in advanced coating developments, by developing laboratory coating durability assessment methodologies in simulated turbine engine conditions and helping establish CMAS test standards in laboratory environments.

Hydrothermal reaction of albite and a sodium aluminosilicate glass: A solid-state NMR study

Science.gov (United States)

Yang, Wang-hong Alex; Kirkpatrick, R. James

1989-04-01

We present here a solid-state NMR study of the structure and chemical composition of the products and mechanisms of the reaction of crystalline low albite and a glass of nearly albite composition with aqueous solutions of pH from 1 to 11 at 250°C. For the crystalline albite, there are no detectable bulk or surface structural changes due to aqueous attack, consistent with the idea that both cation exchange and disruption of the aluminosilicate framework occur only near the mineral/solution interface and that the hydrated surface layer, if it exists, is not more than about 30 Å thick. This reaction occurs by solution/reprecipitation, and its rate decreases with increasing solution pH, supporting the idea that the dissolution of feldspar is initiated by cation-exchange. For the glass, the reaction proceeds by cation exchange of protons for Na +, incorporation of molecular water into the bulk glass, and a small amount of depolymerization of the aluminosilicate framework in the interior of the glass. Cation exchange becomes less important with increasing solution pH. The incorporation of molecular water and cation-exchange cause structural changes in the glass via solidstate adjustment without dissolution/reprecipitation. The large cations in the hydrated glass (Na and K) probably have a shell of water molecules around them, with a maximum average coordination number of six. The secondary phases formed from both albite and the glass are often amorphous and can be well characterized by NMR. The compositional and structural variations of the amorphous phases are important factors in these reactions and cannot be ignored in theoretical models of aluminosilicate dissolution. As expected, the aluminum coordination in the secondary phases changes from six-fold to four-fold as the solution pH increases.

International Union of Basic and Clinical Pharmacology. C. Nomenclature and Properties of Calcium-Activated and Sodium-Activated Potassium Channels.

Science.gov (United States)

Kaczmarek, Leonard K; Aldrich, Richard W; Chandy, K George; Grissmer, Stephan; Wei, Aguan D; Wulff, Heike

2017-01-01

A subset of potassium channels is regulated primarily by changes in the cytoplasmic concentration of ions, including calcium, sodium, chloride, and protons. The eight members of this subfamily were originally all designated as calcium-activated channels. More recent studies have clarified the gating mechanisms for these channels and have documented that not all members are sensitive to calcium. This article describes the molecular relationships between these channels and provides an introduction to their functional properties. It also introduces a new nomenclature that differentiates between calcium- and sodium-activated potassium channels. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

Comparative transcriptome analysis reveals different molecular mechanisms of Bacillus coagulans 2-6 response to sodium lactate and calcium lactate during lactic acid production.

Directory of Open Access Journals (Sweden)

Jiayang Qin

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

Comparative transcriptome analysis reveals different molecular mechanisms of Bacillus coagulans 2-6 response to sodium lactate and calcium lactate during lactic acid production.

Science.gov (United States)

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

2015-01-01

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

Aluminum-induced dreierketten chain cross-links increase the mechanical properties of nanocrystalline calcium aluminosilicate hydrate

Science.gov (United States)

Geng, Guoqing; Myers, Rupert J.; Li, Jiaqi; Maboudian, Roya; Carraro, Carlo; Shapiro, David A.; Monteiro, Paulo J. M.

2017-03-01

The incorporation of Al and increased curing temperature promotes the crystallization and cross-linking of calcium (alumino)silicate hydrate (C-(A-)S-H), which is the primary binding phase in most contemporary concrete materials. However, the influence of Al-induced structural changes on the mechanical properties at atomistic scale is not well understood. Herein, synchrotron radiation-based high-pressure X-ray diffraction is used to quantify the influence of dreierketten chain cross-linking on the anisotropic mechanical behavior of C-(A-)S-H. We show that the ab-planar stiffness is independent of dreierketten chain defects, e.g. vacancies in bridging tetrahedra sites and Al for Si substitution. The c-axis of non-cross-linked C-(A-)S-H is more deformable due to the softer interlayer opening but stiffens with decreased spacing and/or increased zeolitic water and Ca2+ of the interlayer. Dreierketten chain cross-links act as ‘columns’ to resist compression, thus increasing the bulk modulus of C-(A-)S-H. We provide the first experimental evidence on the influence of the Al-induced atomistic configurational change on the mechanical properties of C-(A-)S-H. Our work advances the fundamental knowledge of C-(A-)S-H on the lowest level of its hierarchical structure, and thus can impact the way that innovative C-(A-)S-H-based cementitious materials are developed using a ‘bottom-up’ approach.

Determination of Sodium, Potassium, Magnesium, and Calcium Minerals Level in Fresh and Boiled Broccoli and Cauliflower by Atomic Absorption Spectrometry

Science.gov (United States)

Nerdy

2018-01-01

Vegetables from the cabbage family vegetables consumed by many people, which is known healthful, by eaten raw, boiled, or cooked (stir fry or soup). Vegetables like broccoli and cauliflower contain vitamins, minerals, and fiber. This study aims to determine the decrease percentage of sodium, potassium, magnesium, and calcium minerals level caused by boiled broccoli and cauliflower by atomic absorption spectrometry. Boiled broccoli and cauliflower prepared by given boiled treatment in boiling water for 3 minutes. Fresh and boiled broccoli and cauliflower carried out dry destruction, followed by quantitative analysis of sodium, potassium, magnesium, and calcium minerals respectively at a wavelength of 589.0 nm; 766.5 nm; 285.2 nm; and 422.7 nm, using atomic absorption spectrometry methods. After the determination of the sodium, potassium, magnesium, and calcium minerals level followed by validation of analytical methods with accuracy, precision, linearity, range, limit of detection (LOD), and limit of quantitation (LOQ) parameters. Research results show a decrease in the sodium, potassium, magnesium, and calcium minerals level in boiled broccoli and cauliflower compared with fresh broccoli and cauliflower. Validation of analytical methods gives results that spectrometry methods used for determining sodium, potassium, magnesium, and calcium minerals level are valid. It concluded that the boiled gives the effect of decreasing the minerals level significantly in broccoli and cauliflower.

Indium sulfide precipitation from hydrochloric acid solutions of calcium and sodium chlorides

International Nuclear Information System (INIS)

Kochetkova, N.V.; Bayandina, Yu.E.; Toptygina, G.M.; Shepot'ko, A.O.

1988-01-01

The effect of precipitation duration, acid concentration, indium complexing with chloride ions on the process of indium sulfide chemical precipitation in hydrochloric acid solutions, precipitate composition and dispersity are studied. It is established that indium sulfide solubility increases in solutions with acid concentration exceeding 0.40-0.45 mol/l. Calcium and indium chloride addition to diluted hydrochloric solutions greatly increases the solubility of indium sulfide. The effect of calcium chloride on In 2 S 3 solubility is higher than that of sodium chloride

Comparative Evaluation of Tensile Strength in Die Stone Incorporated with Sodium and Calcium Hypochlorite as Disinfectants: An in vitro Study.

Science.gov (United States)

Pramodh, N R; Kumar, C N Vijay; Pradeep, M R; Naik, Ravi; Mahesh, C S; Kumari, Manju R

2017-12-01

The aim of this study was to evaluate the tensile strength of die stone incorporated with sodium and calcium hypochlorite as disinfectants. Two commercially available type IV die stone (Kalrock: Kalabhai Karson Pvt., Ltd and Pearlstone: Asian Chemicals) and two commercially available disinfectant solutions (sodium hypochlorite and calcium hypochlorite: Beachem Laboratory Chemical Private Limited, Chennai and Leo Chem Private Limited, Bengaluru) were used in this study, and the tensile strength was measured using Lloyd's Universal Testing Machine. The results show that incorporating the disinfecting solutions decreases the tensile strength of both products. The effect of decreasing tensile strength on type IV gypsum product is seen more in calcium hypochlorite when compared with sodium hypochlorite disinfecting solution, and the tensile strength of Kalrock specimens is higher than Pearlstone specimens after disinfecting with sodium hypochlorite and calcium hypochlorite solution. The statistical results also show significant results in all the groups when compared with the control group. The incorporation of sodium and calcium hypochlorite disinfecting solutions is not an encouraging method for both die materials as it reduces the tensile strength of type IV gypsum product. Tensile strength of Kalstone® die material is superior than Pearlstone® die material after mixing with sodium hypochlorite and calcium hypochlorite. According to the recommendations of Americans with Disability Act (ADA) and the Centers for Disease Control and Prevention, disinfecting the whole cast without or minimal changes in physical and mechanical properties was the motto of the study. The tensile strength in type IV gypsum product plays a most important role in retrieval of cast from impression, especially in narrow tooth preparation. This study reveals that incorporating method of disinfecting solutions is not recommended as it reduces the tensile strength.

Treatment of cows with parturient paresis using intravenous calcium and oral sodium phosphate.

Science.gov (United States)

Braun, U; Grob, D; Hässig, M

2016-09-01

The goal of this study was to investigate whether intravenous infusion of 1000 ml 40% calcium borogluconate combined with the oral adminstration of 500 g sodium phosphate leads to a better cure rate and longer-lasting normocalcaemia and normophosphataemia than standard intravenous treatment with 500 ml calcium borogluconate in cows with parturient paresis. Forty recumbent cows with hypocalcaemia and hypophosphataemia were alternately allocated to group A or B. Cows of both groups were treated intravenously with 500 ml 40% calcium borogluconate, and cows of group B additionally received another 500 ml calcium borogluconate via slow intravenous infusion and 500 g sodium phosphate administered via an orogastric tube. Thirty-two cows stood within 8 hours after the start of treatment and 8 did not; of the 32 cows that stood, 18 belonged to group A and 14 to group B (90% of group A vs. 70% of group B; P = 0.23). Seven cows relapsed; of these and the 8 that did not respond to initial treatment, 10 stood after two standard intravenous treatments. Downer cow syndrome occurred in 5 cows, 3 of which recovered after aggressive therapy. The overall cure rate did not differ significantly between groups A and B. Twelve (60%) cows of group A and 14 (70%) cows of group B were cured after a single treatment and of the remaining 14, 11 were cured after two or more treatments. Two downer cows were euthanized and one other died of heart failure during treatment. Serum calcium concentrations during the first eight hours after the start of treatment were significantly higher in group B than in group A, and oral sodium phosphate caused a significant and lasting increase in inorganic phosphate. More cows of group B than group A were cured after a single treatment (P > 0.05). These findings, although not statistically significant, are promising and should be verified using a larger number of cows.

Decomposition of aluminosilicate ores of Afghanistan by hydrochloric acid

International Nuclear Information System (INIS)

Mamatov, E.D.; Khomidi, A.K.

2015-01-01

Present article is devoted to decomposition of aluminosilicate ores of Afghanistan by hydrochloric acid. The physicochemical properties of initial aluminosilicate ores were studied by means of X-ray phase, differential-thermal analysis methods. The chemical and mineral composition of aluminosilicate ores was considered. The kinetics of acid decomposition of aluminosilicate ores composed of two stages was studied as well. The flowsheets of complex processing of aluminium comprising ores by means of chloric and acid methods were proposed.

Intake and hedonics of calcium and sodium during pregnancy and lactation in the rat.

Science.gov (United States)

Leshem, M; Levin, T; Schulkin, J

2002-03-01

These experiments sought to distinguish whether increased calcium intake during pregnancy and lactation in the rat is due to arousal of a specific calcium appetite, with altered taste hedonics, as occurs with sodium depletion, to reduced taste sensitivity, or to the hyperdipsia of reproduction. We find that, during pregnancy and lactation, CaCl(2) intake is not increased more (in fact less) than intakes of control tastants, MgCl(2) and quinine HCl, and multiparous dams do not have a greater calcium intake than primaparous dams. Changes in taste reactivity to CaCl(2) and to NaCl do not correlate with changes in intake of these minerals during pregnancy or lactation, suggesting that alterations in hedonics or sensitivity do not explain the increased intake of these minerals. Taken together with the increased intake of all the tastants, it may be that the increased intakes of calcium and sodium during reproduction are not due to respective specific appetites or to a general mineral appetite but rather to the reproduction-increased ingestion that may meet all the dam's increased mineral and nutrient requirements. Differences in the degree of increased intakes of tastes may be due to specific alterations in their transduction during reproduction.

Cyclic Acetalization of Furfural on Porous Aluminosilicate Acid Catalysts

Directory of Open Access Journals (Sweden)

Hartati Hartati

2016-12-01

Full Text Available Porous aluminosilicate materials included microporous and mesoporous ZSM-5, hierarchical aluminosilicates, and mesoporous aluminosilicate were tested for acetalization of furfural (furan-2-carbaldehyde with propylene glycol. The existing synthesis methods for aluminosilicate and ZSM-5 were modified to produce aluminosilicate material with hierarchical porous structure. Catalytic activity in acetalization of furfural by propylene glycol were conducted by refluxed of the mixture of furfural, propylene glycol and catalyst, using toluene as solvent and nitrobenzene as internal standard, at 106 °C for 4 h. The result showed that a combination of two structure directing agents, tetrapropylammonium hydroxide (TPAOH and cetyltrimethylammonium bromide (CTAB and modification of catalytic crystallization produced an active aluminosilicate framework that provides a wide access for a bulky reactants and strong acid sites to catalyze the reaction. The pore structure and the strength of the Brønsted acid sites were crucial for the high conversion of furfural to produce a cyclic acetal.

Magnesium, calcium, potassium, and sodium intakes and risk of stroke in male smokers.

Science.gov (United States)

Larsson, Susanna C; Virtanen, Mikko J; Mars, Monica; Männistö, Satu; Pietinen, Pirjo; Albanes, Demetrius; Virtamo, Jarmo

2008-03-10

A high intake of magnesium, calcium, and potassium and a low intake of sodium have been hypothesized to reduce the risk of stroke. However, prospective data relating intake of these minerals to risk of stroke are inconsistent. We examined the relationship of dietary magnesium, calcium, potassium, and sodium intake with risk of stroke in a cohort of 26 556 Finnish male smokers, aged 50 to 69 years, who were free from stroke at baseline. Dietary intake was assessed at baseline using a detailed and validated food frequency questionnaire. During a mean follow-up of 13.6 years (1985-2004), 2702 cerebral infarctions, 383 intracerebral hemorrhages, and 196 subarachnoid hemorrhages were identified in the national registries. After adjustment for age and cardiovascular risk factors, a high magnesium intake was associated with a statistically significant lower risk of cerebral infarction but not with intracerebral or subarachnoid hemorrhages. The multivariate relative risk of cerebral infarction was 0.85 (95% confidence interval, 0.76-0.97; P for trend = .004) for men in the highest quintile of magnesium intake compared with those in the lowest quintile. The inverse association between magnesium intake and cerebral infarction was stronger in men younger than 60 years (relative risk, 0.76; 95% confidence interval, 0.64-0.89; P for interaction = .02). Calcium, potassium, and sodium intake was not significantly associated with risk of any subtype of stroke (P for trend > .05). These findings in male smokers suggest that a high magnesium intake may play a role in the primary prevention of cerebral infarction.

Calcium balance in pediatric online hemodiafiltration: Beware of sodium and bicarbonate in the dialysate.

Science.gov (United States)

Bacchetta, Justine; Sellier-Leclerc, Anne-Laure; Bertholet-Thomas, Aurélia; Carlier, Marie-Christine; Cartier, Régine; Cochat, Pierre; Ranchin, Bruno

2015-11-01

Online hemodiafiltration (oHDF) is increasingly used in children; we treated 28 children since 2009, adapting this technique to pediatric patients. In this service evaluation audit, we assessed plasma electrolytes to evaluate the evolution of total (tCa) and ionized (iCa) during a session, as well as dialysate calcium (dCa) concentrations. Using a 1.25 mmol Ca/L-dialysate, both tCa and iCa decreased during the session, with iCa falling below 1.1 mmol/L in 4/5 patients. In contrast, using a 1.5 mmol Ca/L-dialysate, iCa remained normal in all patients. Major discrepancies were observed between the expected and the measured dCa: 1.25 vs. 1.01 (0.83-1.04), and 1.5 vs. 1.47 (0.85-1.75) mmol/L, respectively (results presented as median [range]). These differences were explained by the modality of reconstituting dialysate: increasing bicarbonates and/or decreasing sodium requested in the dialysate decreases calcium extraction from the acid preparation. Proof of concept was given when requesting in an "ex-vivo" setting modifications in the requested sodium and bicarbonate in dialysate directly on the Fresenius machine. Nephrologists should be aware that "high bicarbonate and/or low sodium" requirements in oHDF decrease calcium in the dialysate. Copyright © 2015 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Serum calcium and phosphorus concentrations and the outcome of calciphylaxis treatment with sodium thiosulfate

Czech Academy of Sciences Publication Activity Database

Hlušička, J.; Veisová, E.; Ullrych, M.; Kubeček, J.; Navrátil, Tomáš; Zakharov, S.

2017-01-01

Roč. 148, č. 3 (2017), s. 435-440 ISSN 0026-9247 Institutional support: RVO:61388955 Keywords : Calciphylaxis * Sodium thiosulfate * Serum calcium Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.282, year: 2016

Magnesium, Calcium, Potassium, and Sodium Intakes and Risk of Stroke in Male Smokers

NARCIS (Netherlands)

Larsson, S.C.; Virtanen, M.J.; Mars, M.; Mannisto, S.; Pietinen, P.; Albanes, D.; Virtamo, J.

2008-01-01

Background A high intake of magnesium, calcium, and potassium and a low intake of sodium have been hypothesized to reduce the risk of stroke. However, prospective data relating intake of these minerals to risk of stroke are inconsistent. Methods We examined the relationship of dietary magnesium,

Comparative Potential Protect Effect of HSCAS, Diatomite and ...

African Journals Online (AJOL)

mdenli

bentonite (Rosa et al., 2001), zeolite (Miazzo et al., 2000), hydrated sodium calcium aluminosilicate. (HSCAS) ... Due to these properties diatomite was selected for use in this experiment to compare ..... Aflatoxins in animal and human health.

Influence of man-made aluminosilicate raw materials on physical and mechanical properties of building materials.

Science.gov (United States)

Volodchenko, A. A.; Lesovik, V. S.; Stoletov, A. A.; Glagolev, E. S.; Volodchenko, A. N.; Magomedov, Z. G.

2018-03-01

It has been identified that man-made aluminosilicate raw materials represented by clay rock of varied genesis can be used as energy-efficient raw materials to obtain efficient highly-hollow non-autoclaved silicate materials. A technique of structure formation in the conditions of pressureless steam treatment has been offered. Cementing compounds of non- autoclaved silicate materials based on man-made aluminosilicate raw materials possess hydraulic properties that are conditioned by the process of further formation and recrystallization of calcium silicate hydrates, which optimizes the ratio between gellike and crystalline components and densifies the cementing compound structure, which leads to improvement of performance characteristics. Increasing the performance characteristics of the obtained products is possible by changing the molding conditions. For this reason, in order to create high-density material packaging and, as a result, to increase the strength properties of the products, it is reasonable to use higher pressure, under which raw brick is formed, which will facilitate the increase of quality of highly-hollow products.

Investigation of aluminosilicate refractory for solid oxide fuel cell applications

Science.gov (United States)

Gentile, Paul Steven

Stationary solid oxide fuel cells (SOFCs) have been demonstrated to provide clean and reliable electricity through electro-chemical conversion of various fuel sources (CH4 and other light hydrocarbons). To become a competitive conversion technology the costs of SOFCs must be reduced to less than $400/kW. Aluminosilicate represents a potential low cost alternative to high purity alumina for SOFC refractory applications. The objectives of this investigation are to: (1) study changes of aluminosilicate chemistry and morphology under SOFC conditions, (2) identify volatile silicon species released by aluminosilicates, (3) identify the mechanisms of aluminosilicate vapor deposition on SOFC materials, and (4) determine the effects of aluminosilicate vapors on SOFC electrochemical performance. It is shown thermodynamically and empirically that low cost aluminosilicate refractory remains chemically and thermally unstable under SOFC operating conditions between 800°C and 1000°C. Energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) of the aluminosilicate bulk and surface identified increased concentrations of silicon at the surface after exposure to SOFC gases at 1000°C for 100 hours. The presence of water vapor accelerated surface diffusion of silicon, creating a more uniform distribution. Thermodynamic equilibrium modeling showed aluminosilicate remains stable in dry air, but the introduction of water vapor indicative of actual SOFC gas streams creates low temperature (active anode interface.

Effect of calcium/sodium ion exchange on the osmotic properties and structure of polyelectrolyte gels.

Science.gov (United States)

Horkay, Ferenc; Basser, Peter J; Hecht, Anne-Marie; Geissler, Erik

2015-12-01

We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, they exhibit a reversible volume phase transition. At the macroscopic level, the concentration dependence of the osmotic pressure shows that calcium ions influence primarily the third-order interaction term in the Flory-Huggins model of polymer solutions. Mechanical tests reveal that the elastic modulus is practically unaffected by the presence of calcium ions, indicating that ion bridging does not create permanent cross-links. At the microscopic level, small-angle neutron scattering shows that polyacrylic acid and DNA gels exhibit qualitatively similar structural features in spite of important differences (e.g. chain flexibility and chemical composition) between the two polymers. The main effect of calcium ions is that the neutron scattering intensity increases due to the decrease in the osmotic modulus. At the level of the counterion cloud around dissolved macroions, anomalous small-angle X-ray scattering measurements made on DNA indicate that divalent ions form a cylindrical sheath enveloping the chain, but they are not localized. Small-angle neutron scattering and small-angle X-ray scattering provide complementary information on the structure and interactions in polymer solutions and gels. © IMechE 2015.

In vitro study of the effect of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate on acid-softened enamel.

Science.gov (United States)

Rege, Aarti; Heu, Rod; Stranick, Michael; Sullivan, Richard J

2014-01-01

To investigate the possible mode of action of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and sodium monofluorophosphate in delivering the benefits of preventing acid erosion and rehardening acid-softened enamel. The surfaces of acid-softened bovine enamel specimens were evaluated after application of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate in vitro. Scanning Electron Microscopy (SEM), Electronic Spectrometry for Chemical Analysis (ESCA), and Secondary Ion Mass Spectrometry (SIMS) were used to characterize the enamel surfaces. Exposure of pristine enamel surfaces to citric acid resulted in clear roughening of the surface. Multiple applications of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to the surface of the enamel resulted in the disappearance of the microscopic voids observed by SEM as a function of treatment applications. The ESCA analysis demonstrated that both the nitrogen and carbonate levels increased as the number of treatments increased, which provides evidence that arginine and calcium carbonate were bound to the surface. Observance of arginine's signature mass fragmentation pattern by SIMS analysis confirmed the identity of arginine on the enamel surface. A series of in vitro experiments has demonstrated a possible mode of action by which a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate delivers the benefits of preventing acid erosion and rehardening acid-softened enamel. The combination of arginine and calcium carbonate adheres to the enamel surface and helps to fill the microscopic gaps created by acid, which in turn helps repair the enamel and provides a protective coating against future acid attacks.

No Calcium-Fluoride-Like Deposits Detected in Plaque Shortly after a Sodium Fluoride Mouthrinse

OpenAIRE

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

2010-01-01

Plaque ‘calcium-fluoride-like’ (CaF2-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 μg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2...

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

Science.gov (United States)

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

2012-01-01

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

Spontaneous and CRH-Induced Excitability and Calcium Signaling in Mice Corticotrophs Involves Sodium, Calcium, and Cation-Conducting Channels

Czech Academy of Sciences Publication Activity Database

Zemková, Hana; Tomič, M.; Kučka, M.; Aguilera, G.; Stojilkovic, S. S.

2016-01-01

Roč. 157, č. 4 (2016), s. 1576-1589 ISSN 0013-7227 R&D Projects: GA ČR(CZ) GBP304/12/G069; GA MŠk(CZ) LQ1604; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 Keywords : action potential * background sodium conductance * bursting activity * cation -conducting channels * cytosolic calcium concentration * resting membrane potential Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition Impact factor: 4.286, year: 2016

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

International Nuclear Information System (INIS)

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

2006-01-01

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 key radionuclides, enhanced sorption and minimised corrosion of steel containers. An understanding of the dissolution of C-S-H gels in cement under the appropriate conditions (e.g., saline groundwaters) is necessary to demonstrate the expected evolution of the chemistry over time and to provide sufficient cement to buffer the porewater conditions for the required time. A programme of experimental work has been undertaken to investigate C-S-H gel dissolution behaviour in sodium chloride solutions and the effect of calcium/silicon ratio (C/S), temperature and cation type on this behaviour. Reductions in calcium concentration and pH values were observed with samples equilibrated at 45 deg. C compared to those prepared at 25 deg. C. The effect of salt cation type on salt-concentration dependence of the dissolution of C-S-H gels was investigated by the addition of lithium or potassium chloride in place of sodium chloride for gels with a C/S of 1.0 and 1.8. With a C/S of 1.0, similar increases in dissolved calcium concentration with increasing ionic strength were recorded for the different salts. However, at a C/S of 1.8, anomalously high calcium concentrations were observed in the presence of lithium

On the induction of homogeneous bulk crystallization in Eu-doped calcium aluminosilicate glass by applying simultaneous high pressure and temperature

Energy Technology Data Exchange (ETDEWEB)

Muniz, R. F., E-mail: robsonfmuniz@yahoo.com.br [Institut Lumière Matière, UMR 5306 CNRS-Université Lyon 1, Université de Lyon, 69622 Villeurbanne (France); Departamento de Física, Universidade Estadual de Maringá, 87020900, Maringá, PR (Brazil); Ligny, D. de [Department of Materials Science, Glass and Ceramics, University of Erlangen Nürnberg, Martensstr. 5, 91058 Erlangen (Germany); Le Floch, S.; Martinet, C.; Guyot, Y. [Institut Lumière Matière, UMR 5306 CNRS-Université Lyon 1, Université de Lyon, 69622 Villeurbanne (France); Rohling, J. H.; Medina, A. N.; Sandrini, M.; Baesso, M. L. [Departamento de Física, Universidade Estadual de Maringá, 87020900, Maringá, PR (Brazil); Andrade, L. H. C.; Lima, S. M. [Grupo de Espectroscopia Óptica e Fototérmica, Universidade Estadual de Mato Grosso do Sul, C.P. 351, Dourados, MS (Brazil)

2016-06-28

From initial calcium aluminosilicate glass, transparent glass-ceramics have been successfully synthesized under simultaneous high pressure and temperature (SHPT). Possible homogeneous volumetric crystallization of this glassy system, which was not achieved previously by means of conventional heat treatment, has been put in evidence with a SHPT procedure. Structural, mechanical, and optical properties of glass and glass-ceramic obtained were investigated. Raman spectroscopy and X-ray diffraction allowed to identify two main crystalline phases: merwinite [Ca{sub 3}Mg(SiO{sub 4}){sub 2}] and diopside [CaMgSi{sub 2}O{sub 6}]. A Raman scanning profile showed that the formation of merwinite is quite homogeneous over the bulk sample. However, the sample surface also contains significant diopside crystals. Instrumented Berkovich nanoindentation was applied to determine the effect of SHPT on hardness from glass to glass-ceramic. For Eu-doped samples, the broadband emission due to 4f{sup 6}5d{sup 1} → 4f{sup 7} transition of Eu{sup 2+} was studied in both host systems. Additionally, the {sup 5}D{sub 0} → {sup 7}F{sub J} transition of Eu{sup 3+} was used as an environment probe in the pristine glass and the glass-ceramic.

Crystallization of Yttrium and Samarium Aluminosilicate Glasses

OpenAIRE

Lago, Diana Carolina; Prado, Miguel Oscar

2016-01-01

Aluminosilicate glasses containing samarium and yttrium (SmAS and YAS glasses) exhibit high glass transition temperatures, corrosion resistance, and glass stability on heating which make them useful for technological applications. Yttrium aluminosilicate glass microspheres are currently being used for internal selective radiotherapy of liver cancer. During the preparation process, crystallization needs to be totally or partially avoided depending on the final application. Thus knowing the cry...

Cellular morphology of organic-inorganic hybrid foams based on alkali alumino-silicate matrix

Science.gov (United States)

Verdolotti, Letizia; Liguori, Barbara; Capasso, Ilaria; Caputo, Domenico; Lavorgna, Marino; Iannace, Salvatore

2014-05-01

Organic-inorganic hybrid foams based on an alkali alumino-silicate matrix were prepared by using different foaming methods. Initially, the synthesis of an inorganic matrix by using aluminosilicate particles, activated through a sodium silicate solution, was performed at room temperature. Subsequently the viscous paste was foamed by using three different methods. In the first method, gaseous hydrogen produced by the oxidization of Si powder in an alkaline media, was used as blowing agent to generate gas bubbles in the paste. In the second method, the porous structure was generated by mixing the paste with a "meringue" type of foam previously prepared by whipping, under vigorous stirring, a water solution containing vegetal proteins as surfactants. In the third method, a combination of these two methods was employed. The foamed systems were consolidated for 24 hours at 40°C and then characterized by FTIR, X-Ray diffraction, scanning electron microscopy (SEM) and compression tests. Low density foams (˜500 Kg/m3) with good cellular structure and mechanical properties were obtained by combining the "meringue" approach with the use of the chemical blowing agent based on Si.

Study of the rheological behavior of the calcium and sodium caseinate irradiated dispersions

International Nuclear Information System (INIS)

Sabato, Susy Frey

2002-01-01

Milk isolated proteins has gained a crescent commercial interest due to functional properties allied to excellent nutritional value. These properties could be improved when some treatments are applied, such as gamma-irradiation, combined or not with plasticizers. In the current work, protein solutions (calcium and sodium caseinates) were mixed with glycerol. The mixtures (8% protein base), at the ratios 1:1 and 2:1 (protein: glycerol) were submitted to gamma-irradiation ( 60 Co), in the doses 0 kGy, 5 kGy, 15 kGy and 25 kGy, and the rheological behavior was studied. The irradiation was in a 60 Co source, model Gammacell 220 (AECL), with dose ratio 8.2 kGy/h. The viscosity measurements were made in a Brookfield, model LV-DVIII, spindle SC4-18 and SC4-31, according methodology described previously, at temperature 10.0 deg C ± 0,1 deg C, using a Neslab water bath. As irradiation dose increases, the viscosity measurements decrease significantly (p<0.05) for calcium/glycerol solution. The measurements for sodium/glycerol mixtures remained constant as dose irradiation increases, with a slight augmentation at 5 kGy. (author)

[Optimization of riboflavin sodium phosphate loading to calcium alginate floating microspheres by response surface methodology].

Science.gov (United States)

Zhang, An-yang; Fan, Tian-yuan

2009-12-18

To investigate the preparation, optimization and in vitro properties of riboflavin sodium phosphate floating microspheres. The floating microspheres composed of riboflavin sodium phosphate and calcium alginate were prepared using ion gelatin-oven drying method. The properties of the microspheres were investigated, including the buoyancy, release, appearance and entrapment efficiency. The formulation was optimized by response surface methodology (RSM). The optimized microspheres were round. The entrapment efficiency was 57.49%. All the microspheres could float on the artificial gastric juice over 8 hours. The release of the drug from the microspheres complied with Fick's diffusion.

The Effect of Calcium Sodium Phosphosilicate on Dentin Hypersensitivity: A Systematic Review and Meta-Analysis.

Directory of Open Access Journals (Sweden)

Mengjiao Zhu

Full Text Available To investigate the effect of calcium sodium phosphosilicate (CSPS in treating dentin hypersensitivity (DH and to compare this effect to that of a negative (placebo control.Several databases, including Medline, EMBASE, Web of Science, The Cochrane Library, and the Chinese Biomedical Literature Database, were searched to identify relevant articles published through January 2015; grey literature (i.e., academic literature that is not formally published was also searched. Two authors performed data extraction independently and jointly using data collection forms. The primary outcome was the DH pain response to routine activities or to thermal, tactile, evaporative, or electrical stimuli, and the secondary outcome was the side effects of CSPS use. Each study was evaluated using the Cochrane Collaboration tool for assessing risk bias. Meta-analysis of studies with the same participant demographics, interventions, controls, assessment methods and follow-up periods was performed. The Grading of Recommendations Assessment Development and Evaluation System was used to assess the quality of the evidence and the risk of bias across studies.Meta-analysis demonstrated that toothpaste containing 5% CSPS was more effective than the negative control at relieving dentin sensitivity, with the level of evidence classified as "moderate". In addition, prophylaxis paste containing 15% calcium sodium phosphosilicate was favored over the negative control at reducing post-periodontal therapy hypersensitivity, with the level of evidence categorized as "low". Only two studies reported side effects of CSPS use.The majority of studies found that calcium sodium phosphosilicate was more effective than the negative control at alleviating DH. Because strong evidence is scarce, high-quality, well-designed clinical trials are required in the future before definitive recommendations can be made.

Calcium transport in turtle bladder

International Nuclear Information System (INIS)

Sabatini, S.; Kurtzman, N.A.

1987-01-01

Unidirectional 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 net Ca ) was secretory (serosa to mucosa). Ouabain reversed J net Ca to an absorptive flux. Amiloride reduced both fluxes such that J net 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 net Ca decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, J net Ca was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45 Ca content was ≅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 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 + -K + -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

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

Science.gov (United States)

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

2013-11-18

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 2 min. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

XPS analysis of aluminosilicate microspheres bioactivity tested in vitro

Energy Technology Data Exchange (ETDEWEB)

Todea, M.; Vanea, E. [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania); Bran, S. [University of Medicine and Pharmacy “Iuliu Haţieganu”, Department of Cranio-Maxillofacial Surgery, 400029 Cluj-Napoca (Romania); Berce, P. [Technical University of Cluj-Napoca, Faculty of Machine Building and National Centre of Rapid Prototyping, 400641 Cluj-Napoca (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania)

2013-04-01

The study aims to characterize surface properties of aluminosilicate microspheres incorporating yttrium, with potential biomedical applications. Micrometric particles of spherical shape were obtained by spray drying method. The behavior of aluminosilicate microspheres without yttrium and with yttrium was investigated under in vitro conditions, by seven days incubation in simulated body fluid (SBF). The surface elemental composition and the atomic environments on outermost layer of the microspheres, prior to and after incubation in SBF were evaluated by X-ray photoelectron spectroscopy (XPS) in order to investigate their bioactivity. The results were analyzed to underline the effect of yttrium addition on surface properties of the aluminosilicate microspheres and implicitly on the behavior of the samples in simulated body environments.

Anticaries Potential of a Sodium Monofluorophosphate Dentifrice Containing Calcium Sodium Phosphosilicate: Exploratory in situ Randomized Trial.

Science.gov (United States)

Parkinson, Charles R; Siddiqi, Muhammad; Mason, Stephen; Lippert, Frank; Hara, Anderson T; Zero, Domenick T

2017-01-01

Calcium sodium phosphosilicate (CSPS) is a bioactive glass material that alleviates dentin hypersensitivity and is postulated to confer remineralization of caries lesions. This single-centre, randomized, single (investigator)-blind, placebo-controlled, crossover, in situ study explored whether the addition of 5% CSPS to a nonaqueous fluoride (F) such as sodium monofluorophosphate (SMFP)-containing dentifrice affects its cariostatic ability. Seventy-seven subjects wore 4 gauze-covered enamel specimens with preformed lesions (2 surface-softened and 2 subsurface) placed buccally on their mandibular bilateral dentures for up to 4 weeks. Subjects brushed twice daily with 1 of the 5 study dentifrices: 927 ppm F/5% CSPS, 927 ppm F/0% CSPS, 250 ppm F/0% CSPS, 0 ppm F/5% CSPS, or 0 ppm F/0% CSPS. Specimens were retrieved after either 21 (surface-softened lesions; analyzed by Knoop surface microhardness [SMH]) or 28 days (subsurface lesions; analyzed by transverse microradiography). The enamel fluoride uptake was determined for all specimens using a microbiopsy technique. The concentrations of fluoride and calcium in gauze-retrieved plaque were also evaluated. Higher dentifrice fluoride concentrations led to greater remineralization and fluoridation of both lesion types and increased plaque fluoride concentrations. CSPS did not improve the cariostatic properties of SMFP; there were no statistically significant differences between 927 ppm F/5% CSPS and 927 ppm F/0% CSPS in percent SMH recovery (p = 0.6788), change in integrated mineral loss (p = 0.5908), or lesion depth (p = 0.6622). Likewise, 0 ppm F/5% CSPS did not provide any benefits in comparison to 0 ppm F/0% CSPS. In conclusion, CSPS does not negatively impact nor does it improve the ability of an SMFP dentifrice to affect remineralization of caries lesions. © 2017 S. Karger AG, Basel.

Calcium Transient and Sodium-Calcium Exchange Current in Human versus Rabbit Sinoatrial Node Pacemaker Cells

Directory of Open Access Journals (Sweden)

Arie O. Verkerk

2013-01-01

Full Text Available There is an ongoing debate on the mechanism underlying the pacemaker activity of sinoatrial node (SAN cells, focusing on the relative importance of the “membrane clock” and the “Ca2+ clock” in the generation of the small net membrane current that depolarizes the cell towards the action potential threshold. Specifically, the debate centers around the question whether the membrane clock-driven hyperpolarization-activated current, If, which is also known as the “funny current” or “pacemaker current,” or the Ca2+ clock-driven sodium-calcium exchange current, INaCa, is the main contributor to diastolic depolarization. In our contribution to this journal’s “Special Issue on Cardiac Electrophysiology,” we present a numerical reconstruction of If and INaCa in isolated rabbit and human SAN pacemaker cells based on experimental data on action potentials, If, and intracellular calcium concentration ([Ca2+]i that we have acquired from these cells. The human SAN pacemaker cells have a smaller If, a weaker [Ca2+]i transient, and a smaller INaCa than the rabbit cells. However, when compared to the diastolic net membrane current, INaCa is of similar size in human and rabbit SAN pacemaker cells, whereas If is smaller in human than in rabbit cells.

Investigation on the Stability of Aluminosilicate Colloids by Various Analytical Tools

Energy Technology Data Exchange (ETDEWEB)

Putri, Kirana Y.; Lee, D. H.; Yun, J. I. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2010-05-15

Colloids are ubiquitous in natural aquatic systems. Aquatic colloids may play a significant carrier role for radionuclide migration in aquifer systems. Being omnipresent in natural aquatic systems, aluminosilicate colloids are considered as a kernel for various aquatic colloids. Characterization of aluminosilicate colloids formed under various geochemical conditions is of importance to understand their chemical behavior in natural aquatic systems. In this work, a preliminary study on the formation of aluminosilicate colloids with a help of colorimetry and other colloid detection techniques is presented

On isomorphous substitution of calcium by sodium and lanthanum in synthetic hydroxyapatite

International Nuclear Information System (INIS)

Get'man, E.I.; Kanyuka, Yu.V.; Loboda, S.N.

1998-01-01

Isomorphous substitution of calcium by sodium and lanthanum in synthetic hydroxyapatite Ca 5-2x La x (PO 4 ) 3 OH by x=0-2.5 within the temperature range 1100-800 deg C is studied through the roentgenophase analysis and IR-spectroscopy methods. It is established that singlephase solid solutions are formed in the area of x≥0.4 by a≤0.4 there exist phases with LaPO 4 , LaNa 6 (PO 4 ) 3 structures and unknown phase along with solid solution of the apatite structure

Effect of calcium chloride concentration on output force in electrical actuator made of sodium alginate gel

Science.gov (United States)

Wu, Yuda; Zhao, Gang; Wei, Chengye; Liu, Shuang; Fu, Yu; Liu, Xvxiong

2018-01-01

As a kind of artificial muscle intelligent material, the biological gel electric driver has the advantages of low driving voltage, large strain, good biological compatibility, good flexibility, low price, etc. The application prospect is broad and it has high academic value. Alginate, as a common substance in sea, has characteristics of low cost, green and pollution-free. Therefore,this paper obtains biological gel electric actuator by sodium alginate and calcium chloride. Effects on output force of the electric actuator is researched by changing the crosslinking of calcium chloride concentration and the output force enhancement mechanism is analyzed in this paper.

Aluminosilicate melts and glasses at 1 to 3 GPa: Temperature and pressure effects on recovered structural and density changes

Science.gov (United States)

Bista, S; Stebbins, Jonathan; Hankins, William B.; Sisson, Thomas W.

2015-01-01

In the pressure range in the Earth’s mantle where many basaltic magmas are generated (1 to 3 GPa) (Stolper et al. 1981), increases in the coordination numbers of the network-forming cations in aluminosilicate melts have generally been considered to be minor, although effects on silicon and particularly on aluminum coordination in non-bridging oxygen-rich glasses from the higher, 5 to 12 GPa range, are now well known. Most high-precision measurements of network cation coordination in such samples have been made by spectroscopy (notably 27Al and 29Si NMR) on glasses quenched from high-temperature, high-pressure melts synthesized in solid-media apparatuses and decompressed to room temperature and 1 bar pressure. There are several effects that could lead to the underestimation of the extent of actual structural (and density) changes in high-pressure/temperature melts from such data. For non-bridging oxygen-rich sodium and calcium aluminosilicate compositions in the 1 to 3 GPa range, we show here that glasses annealed near to their glass transition temperatures systematically record higher recovered increases in aluminum coordination and in density than samples quenched from high-temperature melts. In the piston-cylinder apparatus used, rates of cooling through the glass transition are measured as very similar for both higher and lower initial temperatures, indicating that fictive temperature effects are not the likely explanation of these differences. Instead, transient decreases in melt pressure during thermal quenching, which may be especially large for high initial run temperatures, of as much as 0.5 to 1 GPa, may be responsible. As a result, the equilibrium proportion of high-coordinated Al in this pressure range may be 50 to 90% greater than previously estimated, reaching mean coordination numbers (e.g., 4.5) that are probably high enough to significantly affect melt properties. New data on jadeite (NaAlSi2O6) glass confirm that aluminum coordination increase

The influence of calcium magnesium, and sodium on the spectrographic analysis of natural waters

International Nuclear Information System (INIS)

Diaz Guerra, J. P.; Capdevilla, C.

1969-01-01

The influences of 1000 μg/ml of calcium and sodium and 300 μg/ml of magnesium, on the spectrographic determination of Al, Ba, Cr, Fe, Li , Mn, Ni, Pb, Sr and Ti, minor constituents in natural waters, have been studied, In order to eliminate them, the elements Ga, In, La, Ti and Zn, as well as a mixture containing 30 % Tl-70 % In, have been tested as spectrochemical buffers. (Author) 7 refs

Investigating Seed Germination Indices and Absorption Rate of Sodium, Chloride, Calcium, and Potassium in Different Parts of Seedlings of Sweet Corn KSC 403 (Zea Mays L var. Saccharata Under Salinity Stress and Seed Priming

Directory of Open Access Journals (Sweden)

M. Nasrolah alhossini,

2014-02-01

Full Text Available To investigate the effects of different levels of seed priming on germination indices and nutrient absorption at early growth stages of sweet corn (Golden Kernel Hybrid a factorial experiment based on completely randomized design was conducted with three replications in 2011. The experiment consists of 6 levels of primings (seeds without priming, priming with tap water, priming with distilled water, priming with sodium chloride, potassium chloride, and hydrous calcium chloride and five levels of salinity (zero, 4, 8, 12 and 16 ds/m sodium chloride. The characteristics studied were germination percentage, germination rate, root and shoot length, fresh weight and dry weight of seedling, root to shoot ratio and determination of sodium, chloride, calcium, and potassium concentration in different parts of seedlings (stems, roots and seed. The results indicated that increasing salinity stress levels decreased all parameters measured. Priming seeds with hydrated calcium chloride responded to significantly to salinity stress better than other treatments. Results also showed that increasing concentration of sodium chloride salt, increased absorption rate of sodium but concentration of calcium and potassium were reduced. Because application of hydrous calcium chloride stimulates cell in using calcium under salinity conditions it leads to improved seedling growth parameters. To achieve a more accurate results slicing interaction effect of seed priming×salinity levels was performed. Hydrous calcium chloride treatments improved all traits under study except sodium and potassium concentration. This represents a better performance of seeds germination under salinity stress when seeds primed with hydrous calcium chloride.

Development of Li+ alumino-silicate ion source

International Nuclear Information System (INIS)

Roy, P.K.; Seidl, P.A.; Waldron, W.; Greenway, W.; Lidia, S.; Anders, A.; Kwan, J.

2009-01-01

To uniformly heat targets to electron-volt temperatures for the study of warm dense matter, one strategy is to deposit most of the ion energy at the peak of energy loss (dE/dx) with a low (E < 5 MeV) kinetic energy beam and a thin target. Lower mass ions have a peak dE/dx at a lower kinetic energy. To this end, a small lithium (Li+) alumino-silicate source has been fabricated, and its emission limit has been measured. These surface ionization sources are heated to 1000-1150 C where they preferentially emit singly ionized alkali ions. Alumino-silicates sources of K+ and Cs+ have been used extensively in beam experiments, but there are additional challenges for the preparation of high-quality Li+ sources: There are tighter tolerances in preparing and sintering the alumino-silicate to the substrate to produce an emitter that gives uniform ion emission, sufficient current density and low beam emittance. We report on recent measurements ofhigh ( up to 35 mA/cm2) current density from a Li+ source. Ion species identification of possible contaminants is being verified with a Wien (E x B) filter, and via time-of-flight.

Modifications on the properties of a calcium phosphate cement by additions of sodium alginate

International Nuclear Information System (INIS)

Coelho, W.T.; Fernandes, J.M.; Vieira, R.S.; Thurmer, M.B.; Santos, L.A.

2012-01-01

The Calcium Phosphate Cement (CPC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry due to its biocompatibility, bioactivity and osteoconductivity, and form a paste that can be easily shaped and placed into the surgical site. However, CPCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. In order to assess the strength and time to handle a CPC composed primarily of alpha phase, were added sodium alginate (1%, 2% and 3% wt) and an accelerator in an aqueous solution. The cement powder was mixed with liquid of setting, shaped into specimens and evaluated for apparent density and porosity by Archimedes method, X-ray diffraction and compressive strength. A significant increase in compressive strength by adding sodium alginate was verified. (author)

Formation and stability of aluminosilicate colloids by coprecipitation

Energy Technology Data Exchange (ETDEWEB)

Putri, Kirana Yuniati

2011-02-15

Colloids are ubiquitous in natural waters. Colloid-facilitated migration is of importance in safety assessment of a nuclear waste disposal. Aluminosilicate colloids are considered to be the kernel of aquatic colloids. Their stability is affected by a number of geochemical parameters. This work aims to study qualitatively and quantitatively the stability of aluminosilicate colloids formed by coprecipitation under various geochemical conditions, i.e. pH, concentration of Al and Si metal ions, ionic strength, and omnipresent cations (Na{sup +}, Ca{sup 2+}, and Mg{sup 2+}). The work is performed by colorimetric method and laser-induced breakdown detection (LIBD). Two consecutive phase separations at 450 nm and 1 kDa are applied to separate the precipitates and colloids from the ionic species. By means of colorimetry, Si and Al can be detected down to 5.8 x10{sup -8} M and 7.4x10{sup -7} M, respectively. On the other hand, LIBD is able to quantify the colloidal size and its number density down to several ppt. Depending on the concentration of Al and Si metal ions, the formation trend of aluminosilicate colloid changes following its solubility curve. The lower the concentration, the higher the pH range in which the colloids start to emerge. Furthermore, the colloids are stable at higher Al and Si concentration and at low ionic strength. In the low pH range, cations provide different effects at low and high ionic strengths. At high ionic strength, the colloids are stable in the presence of a larger cation, while all cations exhibit similar effects at low ionic strength. However, in the high pH range, valence seems to have a stronger effect than ionic radius; colloids are more stable in the presence of monovalent cations than divalent ones. Meanwhile, XRD shows non- and/or poor crystalline structure of the aluminosilicate species. Nevertheless, results from XPS may suggest that the chemical composition (Si/Al ∼ 0.6) of the aluminosilicate precipitates is sillimanite or

Nanoscale encapsulation: the structure of cations in hydrophobic microporous aluminosilicates

International Nuclear Information System (INIS)

Wasserman, S.R.; Yuchs, S.E.; Giaquinta, D.; Soderholm, L.; Song, Kang.

1996-01-01

Hydrophobic microporous aluminosilicates, created by organic surface modification of inherently hydrophilic materials such as zeolites and clays, are currently being investigated as storage media for hazardous cations. Use of organic monolayers to modify the surface of an aluminosilicate after introducing an ion into the zeolite/clay reduces the interaction of water with the material. Resulting systems are about 20 times more resistant to leaching of stored ion. XAS spectra from the encapsulated ion demonstrate that byproducts from the organic modifier can complex with the stored cation. This complexation can result in a decreased affinity of the cation for the aluminosilicate matrix. Changing the organic modifier eliminates this problem. XAS spectra also indicate that the reactivity and speciation of the encapsulated ion may change upon application of the hydrophobic layer

Total-body sodium and sodium excess

International Nuclear Information System (INIS)

Aloia, J.F.; Cohn, S.H.; Abesamis, C.; Babu, T.; Zanzi, I.; Ellis, K.

1980-01-01

Total-body levels of sodium (TBNa), chlorine (TBCI), calcium (TBCa), and potassium (TBK) were measured by neutron activation and analysis of results by whole body counting in 66 postmenopausal women. The relationship between TBNa, and TBCl, TBK, and TBCa on the one hand, and height and weight on the other, were found to compare with those previously reported. The hypothesis that TBNa and TBCl are distributed normally could not be rejected. The sodium excess (Na/sub es/) is defined as the sodium that is present in excess of that associated with the extracellular fluid (chlorine) space; the Na/sub es/ approximates nonexchangeable bone sodium. In these 66 postmenopausal women, and in patients with different endocrinopathies previously described, the values on Na/sub es/ did not differ from the normal values except in the thyrotoxicosis patients, where they were decreased. A close relationship between Na/sub es/ and TBCa was maintained in the endocrinopathies studied. This relationship was found in conditions accompanied by either an increment or a loss of skeletal mass. It appears that the NA/sub es/ value is primarily dependent upon the calcium content of bone

The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

Science.gov (United States)

Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

2018-01-01

Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

Addition of 1, 2 and 3% in mass of sodium alginate in calcium phosphate cement

International Nuclear Information System (INIS)

Coelho, W.T.; Fernandes, J.M.; Vieira, R.S.; Thurmer, M.B.; Santos, L.A.

2011-01-01

The calcium phosphate cement (CFC) are bone substitutes with great potential for use in orthopedics, traumatology and dentistry because of their biocompatibility, bioactivity, osteoconductivity and osteotransdutivity, and a paste that can be easily molded and placed into the surgical site. However, CFCs have low mechanical strength, which equals the maximum mechanical strength of trabecular bone. Aiming to evaluate the strength and time to handle a CFC phase composed mainly of alpha were added to sodium alginate (1%, 2% and 3% wt) and an accelerator handle in an aqueous medium. The cement powder was mixed with liquid takes 2 minutes and resigned in specimens and assessed for apparent density and porosity by the Archimedes method, X-ray diffraction and mechanical strength. We noticed a significant increase in mechanical properties of cement added sodium alginate. (author)

XANES analysis of calcium and sodium phosphates and silicates and hydroxyapatite-Bioglass (registered) 45S5 co-sintered bioceramics

International Nuclear Information System (INIS)

Demirkiran, Hande; Hu Yongfeng; Zuin, Lucia; Appathurai, Narayana; Aswath, Pranesh B.

2011-01-01

Bioglass (registered) 45S5 was co-sintered with hydroxyapatite at 1200 deg. C. When small amounts ( 5 (PO 4 ) 2 SiO 4 and Na 3 Ca 6 (PO 4 ) 5 in an amorphous silicate matrix respectively. These chemistries show improved bioactivity compared to hydroxyapatite and are the subject of this study. The structure of several crystalline calcium and sodium phosphates and silicates as well as the co-sintered hydroxyapatite-Bioglass (registered) 45S5 bioceramics were examined using XANES spectroscopy. The nature of the crystalline and amorphous phases were studied using silicon (Si) and phosphorus (P) K- and L 2,3 -edge and calcium (Ca) K-edge XANES. Si L 2,3 -edge spectra of sintered bioceramic compositions indicates that the primary silicates present in these compositions are sodium silicates in the amorphous state. From Si K-edge spectra, it is shown that the silicates are in a similar structural environment in all the sintered bioceramic compositions with 4-fold coordination. Using P L 2,3 -edge it is clearly shown that there is no evidence of sodium phosphate present in the sintered bioceramic compositions. In the P K-edge spectra, the post-edge shoulder peak at around 2155 eV indicates that this shoulder to be more defined for calcium phosphate compounds with decreasing solubility and increasing thermodynamic stability. This shoulder peak is more noticeable in hydroxyapatite and β-TCP indicating greater stability of the phosphate phase. The only spectra that does not show a noticeable peak is the composition with Na 3 Ca 6 (PO 4 ) 5 in a silicate matrix indicating that it is more soluble compared to the other compositions.

Modeling strontium-cesium-calcium-magnesium-sodium ion exchange equilibria on chabazite with the Wilson equation

International Nuclear Information System (INIS)

Perona, J.J.

1992-01-01

Chabazite zeolites are used at ORNL for decontamination of wastewaters containing 90 Sr and 137 Cs. Treatability studies have shown that chabazite can remove trace amounts of these nuclides from wastewaters containing much higher concentrations of calcium and magnesium. The design of ion exchange columns for multicomponent systems requires a method for predicting multicomponent equilibria from binary or ternary experiments, since the number of experiments required for an empirical equilibrium model is generally not feasible. Binary interaction parameters for the Wilson equation were used to predict solid-phase activity coefficients for the five-component system, and the sum of squares of deviations between experimental and predicted solution concentrations for the data points available was calculated. The average deviation per data point for the five-component system was about the same as for the calcium-magnesium-sodium ternary system

Modelling of niobium sorption on clay minerals in sodium and calcium perchlorate solutions

Energy Technology Data Exchange (ETDEWEB)

Ervanne, Heini; Hakanen, Martti; Lehto, Jukka [Helsinki Univ. (Finland). Laboratory of Radiochemistry

2014-11-01

The sorption behaviour of niobium on kaolinite and illite minerals in sodium and calcium perchlorate solutions was evaluated with use of the mass distribution coefficient, Rd, obtained in batch sorption experiments. Very high distribution coefficient values, about 100 m{sup 3}/kg, were obtained for both minerals in the neutral pH range between 6 and 8. Values were somewhat lower at pH 5. In NaClO{sub 4} solution, the sorption of niobium starts to decrease at pH higher than 8. This is in agreement with the increase, with pH, in the proportion of anionic niobate species, which are presumed to be low or non-sorbing. A similar decrease was not observed in Ca(ClO{sub 4}){sub 2} solution, probably owing to the influence of Ca on niobium solution speciation and surface species. The surface complexation model was applied to model the Rd values. The model fitted well for the NaClO{sub 4} solution but only at pH below 9 for the Ca(ClO{sub 4}){sub 2} solution. The discrepancy between the strong sorption of niobium in calcium-bearing solution at high pH and the calculated speciation is due in part to the non-inclusion of calcium niobate solution species and Ca-Nb compounds in the present NEA and other similar thermodynamic databases.

Synthesis of calcium silicates by Pechini method and exchanging ions of sodium alginate-calcium chloride

Energy Technology Data Exchange (ETDEWEB)

Flores-Garay, K.A.; Martinez-Luevanos, A.; Cruz-Ortiz, B.R.; Garcia-Cerda, L.A.; Lopez-Badillo, C.M.

2016-07-01

Calcium silicates samples were synthesized using tetraethyl orthosilicate (TEOS) and by Pechini methodology assisted with ion-exchange of sodium alginate, followed by a heat treatment of 800°C by two hours. A, B and C samples were obtained using 1.7×10−3M, 3.4×10−3M and 5.1×10−3M of TEOS, respectively, and without heat treatment; these samples were characterized by thermogravimetric analysis (TGA) and infrared spectroscopy with attenuated total reflectance (FTIR-ATR). Furthermore, samples A800, B800 and C800 obtained using a heat treatment of 800° by two hours were characterized by FTIR-ATR, absorption technique (BET), X-ray diffraction (XRD) and by scanning electron microscopy. The XRD patterns indicate that sample A800 contains olivine (Ca2SiO4) in orthorhombic phase and wollastonite-2M (CaSiO3); sample B800 showed the earlier phases and quartz (SiO2), whereas sample C800 contains wollastonite phases and larnite-2M (Ca2SiO4). (Author)

Aluminosilicate glass thin films elaborated by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Carlier, Thibault [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Saitzek, Sébastien [Univ. Artois, CNRS, Centrale Lille, ENSCL, Univ. Lille, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens (France); Méar, François O., E-mail: francois.mear@univ-lille1.fr [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France); Blach, Jean-François; Ferri, Anthony [Univ. Artois, CNRS, Centrale Lille, ENSCL, Univ. Lille, UMR 8181, Unité de Catalyse et de Chimie du Solide (UCCS), F-62300 Lens (France); Huvé, Marielle; Montagne, Lionel [Univ. Lille, CNRS, Centrale Lille, ENSCL, Univ. Artois, UMR 8181 – UCCS – Unité de Catalyse et Chimie du Solide, F-59000 Lille (France)

2017-03-01

Highlights: • Successfully deposition of a glassy thin film by PLD. • A good homogeneity and stoichiometry of the coating. • Influence of the deposition temperature on the glassy thin-film structure. - Abstract: In the present work, we report the elaboration of aluminosilicate glass thin films by Pulsed Laser Deposition at various temperatures deposition. The amorphous nature of glass thin films was highlighted by Grazing Incidence X-Ray Diffraction and no nanocristallites were observed in the glassy matrix. Chemical analysis, obtained with X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ion Mass Spectroscopy, showed a good transfer and homogeneous elementary distribution with of chemical species from the target to the film a. Structural studies performed by Infrared Spectroscopy showed that the substrate temperature plays an important role on the bonding configuration of the layers. A slight shift of Si-O modes to larger wavenumber was observed with the synthesis temperature, assigned to a more strained sub-oxide network. Finally, optical properties of thins film measured by Spectroscopic Ellipsometry are similar to those of the bulk aluminosilicate glass, which indicate a good deposition of aluminosilicate bulk glass.

A new titanium-bearing calcium aluminosilicate phase. 2: Crystallography and crystal chemistry of grains formed in slowly cooled melts with bulk compositions of calcium-aluminium-rich inclusions

Science.gov (United States)

Barber, David J.; Beckett, John R.; Paque, Julie M.; Stolper, Edward

1994-01-01

The crystallography and crystal chemistry of a new calcium- titanium-aluminosilicate mineral (UNK) observed in synthetic analogs to calcium-aluminum-rich inclusions (CAIs) from carbonaceous chondrites was studied by electron diffraction techniques. The unit cell is primitive hexagonal or trigonal, with a = 0.790 +/- 0.02 nm and c = 0.492 +/- 0.002 nm, similar to the lattice parameters of melilite and consistent with cell dimensions for crystals in a mixer furnace slag described by Barber and Agrell (1994). The phase frequently displays an epitactic relationship in which melilite acts as the host, with (0001)(sub UNK) parallel (001)(sub mel) and zone axis group 1 0 -1 0(sub UNK) parallel zone axis group 1 0 0(sub mel). If one of the two space groups determined by Barber and Agrell (1994) for their sample of UNK is applicable (P3m1 or P31m), then the structure is probably characterized by puckered sheets of octahedra and tetrahedra perpendicular to the c-axis with successive sheets coordinated by planar arrays of Ca. In this likely structure, each unit cell contains three Ca sites located in mirror planes, one octahedrally coordinated cation located along a three-fold axis and five tetrahedrally coordinated cations, three in mirrors and two along triads. The octahedron contains Ti but, because there are 1.3-1.9 cations of Ti/formula unit, some of the Ti must also be in tetrahedral coordination, an unusual but not unprecedented situation for a silicate. Tetrahedral sites in mirror planes would contain mostly Si, with lesser amounts of Al while those along the triads correspondingly contain mostly Al with subordinate Ti. The structural formula, therefore, can be expressed as Ca(sub 3)(sup VIII)(Ti,Al)(sup VI)(Al,Ti,Si)(sub 2)(sup IV)(Si,Al)(sub 3)(sup IV)O14 with Si + Ti = 4. Compositions of meteoritic and synthetic Ti-bearing samples of the phase can be described in terms of a binary solid solution between the end-members Ca3TiAl2Si3O14 and Ca3Ti(AlTi)(AlSi2)O14. A Ti

Effect of sodium adsorption ratio and electric conductivity of the ...

African Journals Online (AJOL)

of the water and its sodium content relative to calcium and magnesium content. ... calcium and magnesium is the sodium adsorption ratio (SAR). It is a measure of the ..... comparison of ANN and geo statistics methods for estimating spatial distribution of sodium adsorption ratio (SAR) in groundwater. Int. J. Agric. Crop Sci.

Determination of calcium, copper, chromium, iron, magnesium, manganese, potassium, sodium and zinc in ethanol by atomic absorption spectrometry

International Nuclear Information System (INIS)

Fernandes, E.A.N.

1981-01-01

The direct determinacao of calcium, copper, chomium, iron, magnesium, manganese, potassium, sodium and zinc in ethanol by atomic absorption spectrometry with, air-acetylene flame is proposed. Effects of fuel/oxidant ratio, burner height and water content in the samples were investigated in detail. The method allows the determition of the elements with good precision (r.s.d. -1 for the elements tested. (author) [pt

Efficient sodium chlorate/calcium/aluminum cathode for polymer light-emitting diodes

International Nuclear Information System (INIS)

Hu Yufeng; Shi Shengwei; Zhang Yanguang; Zhou Quanguo; Wang Lixiang; Ma Dongge; Li Xinglin

2005-01-01

A cathode system comprising an ultra thin sodium chlorate (NaCl) layer and an overlaid calcium (Ca) metal in polymer light-emitting diodes (PLEDs) based on poly[2-methoxy,5-(2-ethylhexoxy)-1,4-phenylene vinylene] is presented. It is demonstrated that introducing a thin NaCl layer further improves the brightness and electroluminescent efficiency of PLEDs. The maximum brightness and efficiency, respectively, reached 22 000 cd/m 2 and 3.5 lm/W for PLEDs with a 1 nm NaCl layer, which are much higher than 18 500 cd/m 2 and 2.0 lm/W for PLEDs with Ca cathode. The investigation of the electron injection in electron-only devices with and without a NaCl layer indicates that the introduction of the NaCl layer substantially enhances the electron injection current, which in case of PLEDs leads to the improvement of the brightness and efficiency

Biochemistry of the normal dura mater of the human brain determination of water, sodium, potassium, calcium, phosphorus, magnesium, copper, iron, sulfur and nitrogen contents

Directory of Open Access Journals (Sweden)

Horacio M. Canelas

1969-06-01

Full Text Available The concentrations of water, sodium, potassium, calcium, phosphorus, magnesium, copper, iron, sulfur, and nitrogen were determined in samples of apparently normal dura mater removed from 18 subjects recently dead by craniocerebral trauma. The average concentrations expressed in dry weight were: water 79.55 g/100 g ± 2.52; sodium 1.63 mequiv/100 g ±0.27; potassium 3.68 mequiv/100 g ± 0.66; calcium 119.84 mg/100 g ± 107.40; phosphorus 68.2 mg/100 g ± 34.5; magnesium 0.61 mequiv/100 g ± 0.37; copper 249.8 /xg/100 g ± 109.4; iron 0.82 mg/100 g ± 0.28; sulfur 490.7 mg/100 g ± 22.5; nitrogen 3.33 g/100 g ± 0.17.

A theoretical and experimental study of calcium, iron, zinc, cadmium, and sodium ions absorption by aspartame.

Science.gov (United States)

Mahnam, Karim; Raisi, Fatame

2017-03-01

Aspartame (L-Aspartyl-L-phenylalanine methyl ester) is a sweet dipeptide used in some foods and beverages. Experimental studies show that aspartame causes osteoporosis and some illnesses, which are similar to those of copper and calcium deficiency. This raises the issue that aspartame in food may interact with cations and excrete them from the body. This study aimed to study aspartame interaction with calcium, zinc, iron, sodium, and cadmium ions via molecular dynamics simulation (MD) and spectroscopy. Following a 480-ns molecular dynamics simulation, it became clear that the aspartame is able to sequester Fe 2+ , Ca 2+ , Cd 2+ , and Zn 2+ ions for a long time. Complexation led to increasing UV-Vis absorption spectra and emission spectra of the complexes. This study suggests a potential risk of cationic absorption of aspartame. This study suggests that purification of cadmium-polluted water by aspartame needs a more general risk assessment.

Hafnium in peralkaline and peraluminous boro-aluminosilicate glass, and glass subcomponents: a solubility study

International Nuclear Information System (INIS)

Davis, Linda L.; Darab, John G.; Qian, Maoxu; Zhao, Donggao; Palenik, Christopher S.; Li, Hong; Strachan, Denis M.; Li, Liyu

2003-01-01

A relationship between the solubility of hafnia (HfO2) and the host glass composition was explored by determining the solubility limits of HfO2 in peralkaline and peraluminous borosilicate glasses in the system SiO2-Al2O3-B2O3-Na2O, and in glasses in the system SiO2-Na2O-Al2O3 in air at 1450 C. The only Hf-bearing phase to crystallize in the peralkaline borosilicate melts is hafnia, while in the boron-free melts sodium-hafnium silicates crystallize. All peraluminous borosilicate melts crystallize hafnia, but the slightly peraluminous glasses also have sector-zoned hafnia crystals that contain Al and Si. The more peraluminous borosilicate glasses also crystallize a B-containing mullite. The general morphology of the hafnia crystals changes as peralkalinity (Na2O/(Na2O+Al2O3)) decreases, as expected in melts with increasing viscosity. In all of the glasses with Na2O > Al2O3, the solubility of hafnia is linearly and positively correlated with Na2O/(Na2O + Al2O3) or Na2O - Al2O3 (excess sodium), despite the presence of 5 to 16 mol% B2O3. The solubility of hafnia is higher in the sodium-aluminum borosilicate glasses than in the sodium-aluminosilicate glasses, suggesting that the boron is enhancing the effect that excess sodium has on the incorporation of Hf into the glass structure. The results of this solubility study are compared to other studies of high-valence cation solubility in B-free silicate melts. From this, for peralkaline B-bearing glasses, it is shown that, although the solubility limits are higher, the solution behavior of hafnia is the same as in B-free silicate melts previously studied. By comparison, also, it is shown that in peraluminous melts, there must be a different solution mechanism for hafnia: different than for peralkaline sodium-aluminum borosilicate glasses and different than for B-free silicate melts studied by others

Nutrient balance of layers fed diets with different calcium levels and the inclusion of phytase and/or sodium butyrate

Directory of Open Access Journals (Sweden)

MM Vieira

2011-06-01

Full Text Available In this study, Hisex Brown layers in lay were evaluated between 40 and 44 weeks of age to evaluate the inclusion of bacterial phytase (Ph and sodium butyrate (SB to diets containing different calcium levels (CaL. Performance, average egg weight and eggshell percentage, in addition to nutrient metabolizability and Ca and P balance were evaluated for 28 days. Birds were distributed according to a completely randomized experimental design with a 3x2x2 factorial arrangement, with three calcium levels (2.8, 3.3, 3.8%; the addition or not of phytase (500PhU/kg and the addition or not of sodium butyrate (20mEq/kg, composing 12 treatments with eight replicates of one bird each. There was no additive effect of phytase or SB on the evaluated responses. Feed intake and feed conversion ratio were influenced by CaL, with the best performance obtained with 3.3% dietary Ca. Ca balance was positively affected by dietary Ca, and P balance by the addition of phytase. Ca dietary concentration, estimated to obtain Ca body balance, was 3.41%, corresponding to an apparent retention of 59.9% of Ca intake.

Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX)

Energy Technology Data Exchange (ETDEWEB)

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.; Wu, James K.

2010-10-01

We report results on lithium alumino-silicate ion source development in preparation for warmdense-matter heating experiments on the new Neutralized Drift Compression Experiment (NDCXII). The practical limit to the current density for a lithium alumino-silicate source is determined by the maximum operating temperature that the ion source can withstand before running into problems of heat transfer, melting of the alumino-silicate material, and emission lifetime. Using small prototype emitters, at a temperature of ~;;1275 oC, a space-charge-limited Li+ beam current density of J ~;;1 mA/cm2 was obtained. The lifetime of the ion source was ~;;50 hours while pulsing at a rate of 0.033 Hz with a pulse duration of 5-6 mu s.

Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX)

International Nuclear Information System (INIS)

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.; Seidl, Peter A.; Waldron, William L.; Wu, James K.

2010-01-01

We report results on lithium alumino-silicate ion source development in preparation for warm-dense-matter heating experiments on the new Neutralized Drift Compression Experiment (NDCX-II). The practical limit to the current density for a lithium alumino-silicate source is determined by the maximum operating temperature that the ion source can withstand before running into problems of heat transfer, melting of the alumino-silicate material, and emission lifetime. Using small prototype emitters, at a temperature of ∼1275 C, a space-charge-limited Li + beam current density of J ∼1 mA/cm 2 was obtained. The lifetime of the ion source was ∼50 hours while pulsing at a rate of 0.033 Hz with a pulse duration of 5-6 (micro) s.

Anticaries effect of dentifrices with calcium citrate and sodium trimetaphosphate

Directory of Open Access Journals (Sweden)

Alberto Carlos Botazzo Delbem

2012-02-01

Full Text Available Because of the growing concerns regarding fluoride ingestion by young children and dental fluorosis, it is necessary to develop new dentifrices. OBJECTIVE: The aim of this study was to evaluate the effect of dentifrices with calcium citrate (Cacit and sodium trimetaphosphate (TMP on enamel demineralization. MATERIAL AND METHODS: Enamel blocks (n=70, previously selected through surface hardness analysis, were submitted to daily treatment with dentifrices diluted in artificial saliva and to a pH-cycling model. The fluoride concentration in dentifrices was 0, 250, 450, 550, 1,000 and 1,100 µg F/g. CrestTM was used as a positive control (1,100 mg F/g. Cacit (0.25% and TMP (0.25% were added to dentifrices with 450 and 1,000 µg F/g. Surface hardness was measured again and integrated loss of subsurface hardness and fluoride concentration in enamel were calculated. Parametric and correlation tests were used to determine difference (p0.05. CONCLUSIONS: Dentifrices with 450 and 1,000 µg F/g, Cacit and TMP were as effective as a gold standard one.

Study of interaction of bismuth, strontium, calcium copper, lead nitrates solutions with sodium oxalate solution with the aim of HTSC synthesis

International Nuclear Information System (INIS)

Danilov, V.P.; Krasnobaeva, O.N.; Nosova, T.A.

1993-01-01

With the aim of developing a new technique for HTSC oxides synthesis on the base of combined sedimentation of hydroxy salts and their heat treatment is studied interaction of bismuth, strontium, calcium, copper and lead nitrates with alkali solution of sodium oxalate. Conditions for total sedimentation of all five metals from the solution are found. The phase composition of interaction products is determined. It is established that they are high-dispersed homogeneous mixture of three phases of variable composition: twin hydroxalate of copper-bismuth, lead hydroxalate and twin oxalate of strontium-calcium. After heat treatment of the phases are obtained the HTSC oxides

XANES analysis of calcium and sodium phosphates and silicates and hydroxyapatite-Bioglass (registered) 45S5 co-sintered bioceramics

Energy Technology Data Exchange (ETDEWEB)

Demirkiran, Hande [Graduate Student, Materials Science and Engineering Department, University of Texas at Arlington, Arlington, TX (United States); Hu Yongfeng; Zuin, Lucia [Beamline Scientist, Canadian Light Source, Saskatoon, SK (Canada); Appathurai, Narayana [Beamline Scientist, Synchrotron Radiation Center, Madison, WI (United States); Aswath, Pranesh B., E-mail: aswath@uta.edu [Materials Science and Engineering Department, University of Texas at Arlington, Arlington, TX (United States)

2011-03-12

Bioglass (registered) 45S5 was co-sintered with hydroxyapatite at 1200 deg. C. When small amounts (< 5 wt.%) of Bioglass (registered) 45S5 was added it behaved as a sintering aid and also enhanced the decomposition of hydroxyapatite to {beta}-tricalcium phosphate. However when 10 wt.% and 25 wt.% Bioglass (registered) 45S5 was used it resulted in the formation of Ca{sub 5}(PO{sub 4}){sub 2}SiO{sub 4} and Na{sub 3}Ca{sub 6}(PO{sub 4}){sub 5} in an amorphous silicate matrix respectively. These chemistries show improved bioactivity compared to hydroxyapatite and are the subject of this study. The structure of several crystalline calcium and sodium phosphates and silicates as well as the co-sintered hydroxyapatite-Bioglass (registered) 45S5 bioceramics were examined using XANES spectroscopy. The nature of the crystalline and amorphous phases were studied using silicon (Si) and phosphorus (P) K- and L{sub 2,3}-edge and calcium (Ca) K-edge XANES. Si L{sub 2,3}-edge spectra of sintered bioceramic compositions indicates that the primary silicates present in these compositions are sodium silicates in the amorphous state. From Si K-edge spectra, it is shown that the silicates are in a similar structural environment in all the sintered bioceramic compositions with 4-fold coordination. Using P L{sub 2,3}-edge it is clearly shown that there is no evidence of sodium phosphate present in the sintered bioceramic compositions. In the P K-edge spectra, the post-edge shoulder peak at around 2155 eV indicates that this shoulder to be more defined for calcium phosphate compounds with decreasing solubility and increasing thermodynamic stability. This shoulder peak is more noticeable in hydroxyapatite and {beta}-TCP indicating greater stability of the phosphate phase. The only spectra that does not show a noticeable peak is the composition with Na{sub 3}Ca{sub 6}(PO{sub 4}){sub 5} in a silicate matrix indicating that it is more soluble compared to the other compositions.

Application of Response Surface Methodology to study the effect of different calcium sources in fish muscle-alginate restructured products

Directory of Open Access Journals (Sweden)

Helena María Moreno

2011-03-01

Full Text Available Sodium alginate needs the presence of calcium ions to gelify. For this reason, the contribution of the calcium source in a fish muscle mince added by sodium alginate, makes gelification possible, resulting a restructured fish product. The three different calcium sources considered were: Calcium Chloride (CC; Calcium Caseinate (CCa; and Calcium lactate (CLa. Several physical properties were analyzed, including mechanical properties, colour and cooking loss. Response Surface Methodology (RSM was used to determine the contribution of different calcium sources to a restructured fish muscle. The calcium source that modifies the system the most is CC. A combination of CC and sodium alginate weakened mechanical properties as reflected in the negative linear contribution of sodium alginate. Moreover, CC by itself increased lightness and cooking loss. The mechanical properties of restructured fish muscle elaborated were enhanced by using CCa and sodium alginate, as reflected in the negative linear contribution of sodium alginate. Also, CCa increased cooking loss. The role of CLa combined with sodium alginate was not so pronounced in the system discussed here.

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

Energy Technology Data Exchange (ETDEWEB)

Schumaker, Karen S [Professor

2013-10-24

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

Characterization of Uranium Solids Precipitated with Aluminosilicates

International Nuclear Information System (INIS)

DUFF, MC

2004-01-01

At the Savannah River Site (SRS), the High-Level Waste (HLW) Tank Farms store and process high-level liquid radioactive wastes from the Canyons and recycle water from the Defense Waste Processing Facility. The waste is concentrated using evaporators to minimize the volume of space required for HLW storage. Recently, the 2H Evaporator was shutdown due to the crystallization of sodium aluminosilicate (NAS) solids (such as cancrinite and sodalite) that contained close to 10 weight percent of elementally-enriched uranium (U). Prior to extensive cleaning,the evaporator deposits resided on the evaporator walls and other exposed internal surfaces within the evaporator pot. Our goal is to support the basis for the continued safe operation of SRS evaporators and to gain more information that could be used to help mitigate U accumulation during evaporator operation. To learn more about the interaction between U(VI) and NAS in HLW salt solutions, we performed several fundamental studies to examine the mechanisms of U accumulation with NAS in highly caustic solutions. This larger group of studies focused on the following processes: co-precipitation/structural incorporation, sorption, and precipitation (with or without NAS), which will be reviewed in this presentation. We will present and discuss local atomic structural characterization data about U that has been co-precipitated with NAS solids (such as amorphous zeolite precursor material and sodalite) using X-ray absorption fine-structure (XAFS) spectroscopic techniques

Immobilization of aqueous radioactive cesium wastes by conversion to aluminosilicate minerals

International Nuclear Information System (INIS)

Barney, G.S.

1975-05-01

Radioactive cesium (primarily 137 Cs) is a major toxic constituent of liquid wastes from nuclear fuel processing plants. Because of the long half-life, highly penetrating radiation, and mobility of 137 Cs, it is necessary to convert wastes containing this radioisotope into a solid form which will prevent movement to the biosphere during long-term storage. A method for converting cesium wastes to solid, highly insoluble, thermally stable aluminosilicate minerals is described. Aluminum silicate clays (bentonite, kaolin, or pyrophyllite) or hydrous aluminosilicate gels are reacted with basic waste solutions to form pollucite, cesium zeolite (Cs-D), Cs-F, cancrinite, or nepheline. Cesium is trapped in the aluminosilicate crystal lattice of the mineral and is permanently immobilized. The identity of the mineral product is dependent on the waste composition and the SiO 2 /Al 2 O 3 ratio of the clay or gel. The stoichiometry and kinetics of mineral formation reactions are described. The products are evaluated with respect to leachability, thermal stability, and crystal morphology. (U.S.)

Catalysts based on mesoporous aluminosilicates for the hydroisomerization and hydrodearomatization processes

Energy Technology Data Exchange (ETDEWEB)

Vilesov, A.S.; Kulikov, A.B. [Russian Academy of Sciences (Russian Federation). A.V. Topchiev Inst. of Petrochemical Synthesis; Ostroumova, V.A.; Baranova, S.V.; Lysenko, S.V.; Kardashev, S.V.; Lasarev, A.V.; Egazaryants, S.V.; Karakhanov, E.A. [Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.; Maximov, A.L. [Russian Academy of Sciences (Russian Federation). A.V. Topchiev Inst. of Petrochemical Synthesis; Lomonosov Moscow State Univ. (Russian Federation). Chemistry Dept.

2011-07-01

In the present work the activity of bifunctional catalysts based on mesoporous aluminosilicates in the hydroisomerization of n-alkanes and the hydrodearomatization (HDA) process has been investigated. The structured mesoporous aluminosilicates (Si/Al = 5/30) were prepared using hexadecylamine and Pluronic P{sub 123} as templates, with a specific surface area up to 1030 m{sup 2}/g and a pore size from 33 to 84 A. Bifunctional catalysts were prepared in the form of extrudates using boehmite as a binder with the platinum content of 0,5% by mass. The experiment was carried out in a flow reactor. The highest selectivity in the isomerization of n-dodecane and n-hexadecane was shown by catalysts based on mesoporous aluminosilicates with Si/Al =10 and 20. In the hydrogenation of a model feed of 10% (wt.) naphthalene in benzene, it was established that, depending on the module aluminosilicate, the conversion of naphthalene to decalin and tetralin may proceed quantitatively with no conversion of benzene to cyclohexane. Selectivity was in the range from 55 to 90% by decalin, and from 10 to 45% by tetralin. We found the conditions under which the only product of the hydrogenation of naphthalene is tetralin, but the conversion of naphthalene was up to 65%. Also, the activity of such catalysts for hydroisomerization and hydrodearomatization processes on the hydrotreated straight-run diesel fraction was investigated. It was established, that due to hydroisomerization, the maximum filtration temperature goes under -38 C, that allows to use it as a component of winter and arctic diesel fuels. (orig.)

EFFECTS OF SODIUM AND CALCIUM IN LIGNITE ON THE PERFORMANCE OF ACTIVATED CARBON PRODUCTS; TOPICAL

International Nuclear Information System (INIS)

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

2001-01-01

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

High-aluminum-affinity silica is a nanoparticle that seeds secondary aluminosilicate formation.

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Ravin Jugdaohsingh

Full Text Available Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7 we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP. Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m(2 g(-1 and it competes effectively with transferrin for Al(III binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III species binding monomeric silica to form early phase, non-toxic aluminosilicates.

High-Aluminum-Affinity Silica Is a Nanoparticle That Seeds Secondary Aluminosilicate Formation

Science.gov (United States)

Jugdaohsingh, Ravin; Brown, Andy; Dietzel, Martin; Powell, Jonathan J.

2013-01-01

Despite the importance and abundance of aluminosilicates throughout our natural surroundings, their formation at neutral pH is, surprisingly, a matter of considerable debate. From our experiments in dilute aluminum and silica containing solutions (pH ~ 7) we previously identified a silica polymer with an extraordinarily high affinity for aluminium ions (high-aluminum-affinity silica polymer, HSP). Here, further characterization shows that HSP is a colloid of approximately 2.4 nm in diameter with a mean specific surface area of about 1,000 m2 g-1 and it competes effectively with transferrin for Al(III) binding. Aluminum binding to HSP strongly inhibited its decomposition whilst the reaction rate constant for the formation of the β-silicomolybdic acid complex indicated a diameter between 3.6 and 4.1 nm for these aluminum-containing nanoparticles. Similarly, high resolution microscopic analysis of the air dried aluminum-containing silica colloid solution revealed 3.9 ± 1.3 nm sized crystalline Al-rich silica nanoparticles (ASP) with an estimated Al:Si ratio of between 2 and 3 which is close to the range of secondary aluminosilicates such as imogolite. Thus the high-aluminum-affinity silica polymer is a nanoparticle that seeds early aluminosilicate formation through highly competitive binding of Al(III) ions. In niche environments, especially in vivo, this may serve as an alternative mechanism to polyhydroxy Al(III) species binding monomeric silica to form early phase, non-toxic aluminosilicates. PMID:24349573

Efficacy of supplemental natural zeolite in broiler chickens subjected to dietary calcium deficiency

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Erol Bintaş

2014-04-01

Full Text Available Natural zeolite, or sodium aluminosilicate, influences calcium (Ca and phosphorus (P utilisation in chicks. A 2×2 factorial arrangement of treatments was used to investigate the effect of dietary Ca (recommended and below recommended levels and zeolite (0 and 0.8% on growth, plasma, tibia and faeces in chickens from 1 to 42 days of age. Zeolite supplementation did not affect overall body weight (BW gain, feed intake (FI or feed conversion ratio (FCR of broiler chickens (P>0.05. Overall mortality of zeolite-fed chickens was lower than in untreated ones (P<0.01. Reduction of dietary Ca of approximately 10 to 18% decreased (P<0.05 BW at 14 and 42 days of age in association with reduced FI, but overall FCR was unchanged. Serum protein and sodium constituents were reduced in birds fed zeolite (P<0.05. Decreasing dietary Ca level increased (P<0.01 serum, total protein and glucose concentrations, but decreased Ca level. Zeolite decreased bone ash in birds fed a Ca-deficient diet while increased faecal excretion of ash, Ca, P and aluminum. However, zeolite increased tibia weight (P<0.05 and thickness (P<0.01. No significant response (P>0.05 in relative weight and gross lesion scores of liver or footpad lesion scores was found related to changes in dietary regimens. The results of the present study do not corroborate the hypothesis that the effectiveness of zeolite may be improved in Ca-deficient diets in association with its ion exchange capability.

Normal levels of total body sodium and chlorine by neutron activation analysis

International Nuclear Information System (INIS)

Kennedy, N.S.J.; Eastell, R.; Smith, M.A.; Tothill, P.

1983-01-01

In vivo neutron activation analysis was used to measure total body sodium and chlorine in 18 male and 18 female normal adults. Corrections for body size were developed. Normalisation factors were derived which enable the prediction of the normal levels of sodium and chlorine in a subject. The coefficient of variation of normalised sodium was 5.9% in men and 6.9% in women, and of normalised chlorine 9.3% in men and 5.5% in women. In the range examined (40-70 years) no significant age dependence was observed for either element. Total body sodium was correlated with total body chlorine and total body calcium. Sodium excess, defined as the amount of body sodium in excess of that associated with chlorine, also correlated well with total body calcium. In females there was a mean annual loss of sodium excess of 1.2% after the menopause, similar to the loss of calcium. (author)

The geochemical evolution of aqueous sodium in the Black Creek Aquifer, Horry and Georgetown counties, South Carolina

Science.gov (United States)

Zack, Allen L.; Roberts, Ivan

1988-01-01

The Black Creek aquifer contains dilute seawater near the North Carolina State line, probably the result of incomplete flushing of ancient seawater. Data do not indicate that the dilute seawater has migrated toward areas of fresh ground-water withdrawals. The concentration of chloride in ground-water samples ranges from 5 to 720 milligrams per liter and that of sodium from 160 to 690 milligrams per liter. Ion-exchange reactions (sodium for calcium and fluoride for hydroxyl) occur with the calcium carbonate dissolution reaction which produces calcium, bicarbonate, and hydroxyl ions. The reaction sequence and stoichiometry result in an aqueous solution in which the sum of bicarbonate and chloride equivalents per liter is equal to the equivalents per liter of sodium. Calcium ions are exchanged for sodium ions derived from sodium-rich clays upgradient of the dilute seawater. The cation-exchange reaction equilibrates at a sodium concentration of 280 milligrams per liter. Amounts of sodium greater than 280 milligrams per liter are contributed from dilute seawater. The cation-exchange reaction approaches an equilibrium which represents a mass-action limit in terms of the ratio of sodium to calcium in solution versus the ratio of exchangeable sodium to calcium on clay surfaces. Where the limit of calcium carbonate solubility is approached and dissolution ceases, some precipitation of calcite probably takes place. The dissolution of calcite exposes fossil shark teeth which release fluoride ions to the ground water through anion exchange with aqueous hydroxyl ions.

Prostaglandin E2 release from dermis regulates sodium permeability of frog skin epithelium

DEFF Research Database (Denmark)

Rytved, Klaus A.; Brodin, Birger; Nielsen, Robert

1995-01-01

Arachidonic acid, cAMP, epithelium, frog skin, intracellular calcium, prostaglandin E*U2, sodium transport, tight epithelium.......Arachidonic acid, cAMP, epithelium, frog skin, intracellular calcium, prostaglandin E*U2, sodium transport, tight epithelium....

Enhanced osteoconductivity of sodium-substituted hydroxyapatite by system instability.

Science.gov (United States)

Sang Cho, Jung; Um, Seung-Hoon; Su Yoo, Dong; Chung, Yong-Chae; Hye Chung, Shin; Lee, Jeong-Cheol; Rhee, Sang-Hoon

2014-07-01

The effect of substituting sodium for calcium on enhanced osteoconductivity of hydroxyapatite was newly investigated. Sodium-substituted hydroxyapatite was synthesized by reacting calcium hydroxide and phosphoric acid with sodium nitrate followed by sintering. As a control, pure hydroxyapatite was prepared under identical conditions, but without the addition of sodium nitrate. Substitution of calcium with sodium in hydroxyapatite produced the structural vacancies for carbonate ion from phosphate site and hydrogen ion from hydroxide site of hydroxyapatite after sintering. The total system energy of sodium-substituted hydroxyapatite with structural defects calculated by ab initio methods based on quantum mechanics was much higher than that of hydroxyapatite, suggesting that the sodium-substituted hydroxyapatite was energetically less stable compared with hydroxyapatite. Indeed, sodium-substituted hydroxyapatite exhibited higher dissolution behavior of constituent elements of hydroxyapatite in simulated body fluid (SBF) and Tris-buffered deionized water compared with hydroxyapatite, which directly affected low-crystalline hydroxyl-carbonate apatite forming capacity by increasing the degree of apatite supersaturation in SBF. Actually, sodium-substituted hydroxyapatite exhibited markedly improved low-crystalline hydroxyl-carbonate apatite forming capacity in SBF and noticeably higher osteoconductivity 4 weeks after implantation in calvarial defects of New Zealand white rabbits compared with hydroxyapatite. In addition, there were no statistically significant differences between hydroxyapatite and sodium-substituted hydroxyapatite on cytotoxicity as determined by BCA assay. Taken together, these results indicate that sodium-substituted hydroxyapatite with structural defects has promising potential for use as a bone grafting material due to its enhanced osteoconductivity compared with hydroxyapatite. © 2013 Wiley Periodicals, Inc.

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

Energy Technology Data Exchange (ETDEWEB)

Gaudioso, Christelle; Carlier, Edmond; Youssouf, Fahamoe [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France); Clare, Jeffrey J. [Eaton Pharma Consulting, Eaton Socon, Cambridgeshire PE19 8EF (United Kingdom); Debanne, Dominique [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France); Alcaraz, Gisele, E-mail: gisele.alcaraz@univmed.fr [INSERM U641, Institut Jean Roche, Marseille F-13344 (France); Universite de la Mediterranee, Faculte de Medecine Secteur Nord, IFR 11, Marseille F-13344 (France)

2011-07-29

Highlights: {yields} Both Ca{sup ++}-Calmodulin (CaM) and Ca{sup ++}-free CaM bind to the C-terminal region of Nav1.1. {yields} Ca{sup ++} and CaM have both opposite and convergent effects on I{sub Nav1.1}. {yields} Ca{sup ++}-CaM modulates I{sub Nav1.1} amplitude. {yields} CaM hyperpolarizes the voltage-dependence of activation, and increases the inactivation rate. {yields} Ca{sup ++} alone antagonizes CaM for both effects, and depolarizes the voltage-dependence of inactivation. -- Abstract: 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{sup ++} 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{sup ++} could bind the Nav1.1 C-terminal region with micromolar affinity.

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

Science.gov (United States)

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

2010-01-01

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. (c) 2010 S. Karger AG, Basel.

Preparation of calcium phosphate paste

International Nuclear Information System (INIS)

Mohd Reusmaazran Yusof; Norzita Yaacob; Idris Besar; Che Seman Mahmood; Rusnah Mustafa

2010-01-01

Calcium phosphate paste were prepared by mixing between calcium sodium potassium phosphate, Ca 2 NaK (PO 4 ) 2 (CSPP) and monocalcium phosphate monohydrate, Ca(H 2 PO 4 ) 2 .H 2 O (MCPM). CSPP were obtained by reaction between calcium hydrogen phosphate (CaHPO 4 ), potassium carbonate (K 2 CO 3 ) and sodium carbonate (Na 2 CO 3 ) in solid state sintering process followed by quenching in air at 1000 degree Celsius. The paste was aging in simulated body fluid (SBF) for 0.5, 1, 3, 6, 12, 24, 48 hrs, 3, 7 and 14 days. The morphological investigation indicated the formation of apatite crystal were first growth after 24 hours. The obvious growth of apatite crystal was shown at 3 days. The obvious growth of apatite crystal was shown in 7 and 14 days indicated the prediction of paste would have rapid reaction with bone after implantation. (author)

Measurement of the body content of sodium, potassium, chloride, calcium, phophorus and nitrogen with reference to spironolactone

International Nuclear Information System (INIS)

Boddy, K.

1978-01-01

The total body content of sodium, chloride, nitrogen, calcium and phosphorus can be measured simultaneously by in vivo activation analysis and at the same time total body potassium can be determined directly by whole body counting. These procedures have been described and compared with methods using isotope dilution. The complementary nature of the techniques, when properly applied, as well as reported disparities have been illustrated by a number of clinical investigations generally involving aldosterone antagonists. The methods should provide a better insight to the complex changes in body conposition and metabolism accociated with hypertension (and other diseases) and their treatment. (Auth.)

Effect of a Sodium and Calcium DL-β-Hydroxybutyrate Salt in Healthy Adults

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Tobias Fischer

2018-01-01

Full Text Available Background. Ketone body therapy and supplementation are of high interest for several medical and nutritional fields. The intake of ketone bodies is often discussed in relation to rare metabolic diseases, such as multiple acyl-CoA dehydrogenase deficiency (MADD, that have no alternatives for treatment. Case reports showed positive results of therapy using ketone bodies. The number of ketone body salts offered on the wellness market is increasing steadily. More information on the kinetics of intake, safety, and tolerance of these products is needed. Methods. In a one-dose kinetic study, six healthy subjects received an intervention (0.5 g/kg bw using a commercially available ketone body supplement. The supplement contained a mixture of sodium and calcium D-/L-β-hydroxybutyrate (βHB as well as food additives. The blood samples drawn in the study were tested for concentrations of D-βHB, glucose, and electrolytes, and blood gas analyses were done. Data on sensory evaluation and observed side effects of the supplement were collected. The product also went through chemical food analysis. Results. The supplement led to a significant increase of D-βHB concentration in blood 2.5 and 3 h after oral intake (p=0.033;  p=0.043. The first significant effect was measured after 2 h with a mean value of 0.598 ± 0.300 mmol/L at the peak, which was recorded at 2.5 h. Changes in serum electrolytes and BGA were largely unremarkable. Taking the supplement was not without side effects. One subject dropped out due to gastrointestinal symptoms and two others reported similar but milder problems. Conclusions. Intake of a combination of calcium and sodium D-/L-βHB salt shows a slow resorption with a moderate increase of D-βHB in serum levels. An influence of βHB salts on acid-base balance could not be excluded by this one-dose study. Excessive regular consumption without medical observation is not free of adverse effects. The tested product can

Comparative study of sodium and potassium in different types of gallstones and in serum of subjects with gallstones and controls

International Nuclear Information System (INIS)

Channa, N.A.; Ghanghro, A.B.; Soomro, A.M.

2008-01-01

The study comprises evaluation of sodium and potassium in the pathogenesis of human gallstones as well as measurement of the concentration of these elements in gallstones and in sera of 109 gallstone subjects and 100 controls (age and sex matched with no personal or family history of gallstone disease). It was observed that serum concentrations for both sodium and potassium were comparable (p<0.05) between gallstone subjects and control subjects. In gallstones the concentration of sodium was significantly higher as compared to potassium (p<0.5). Normal sodium to potassium ratio was seen in serum of gallstone subject, whereas, low sodium to potassium ratio was seen in gallstone carriers. Amongst the different types of gallstones, significantly high (p<0.05) concentrations of sodium and potassium were seen in calcium bilirubinate gallstones. The levels for these mineral elements were also raised in serum of pure calcium carbonate gallstone subjects. The results demonstrate that the higher concentration of sodium and potassium in gallstones may involve in both calcium bilirubinate gallstones and in serum of calcium carbonate gallstone subjects, which indicate their association with calcium in the precipitation of calcium bilirubinate and calcium carbonate in bile. Furthermore, low sodium to potassium ratio in gallstones indicates low ratio in bile of gallstone subjects. (author)

Comparative Study of Sodium and Potassium in Different Types of Gallstones and in Serum of Subjects with Gallstones and Controls

Directory of Open Access Journals (Sweden)

Ali Mohammad Soomro

2008-06-01

Full Text Available The study comprises evaluation of sodium and potassium in the pathogenesis of human gallstones as well as measurement of the concentration of these elements in gallstones and in sera of 109 gallstone subjects and 100 controls (age and sex matched with no personal or family history of gallstone disease. It was observed that serum concentrations for both sodium and potassium were comparable (p>0.05 between gallstone subjects and control subjects. In gallstones the concentration of sodium was significantly higher as compared to potassium (p<0.05. Normal sodium to potassium ratio was seen in serum of gallstone subjects, whereas, low sodium to potassium ratio was seen in gallstone carriers. Amongst the different types of gallstones, significantly high (p<0.05 concentrations of sodium and potassium were seen in calcium bilirubinate gallstones. The levels for these mineral elements were also raised in serum of pure calcium carbonate gallstone subjects.The results demonstrate that the higher concentration of sodium and potassium in gallstones may involve in both calcium bilirubinate gallstones and in serum of calcium carbonate gallstone subjects, which indicate their association with calcium in the precipitation of calcium bilirubinate and calcium carbonate in bile. Furthermore, low sodium to potassium ratio in gallstones indicates low ratio in bile of gallstone subjects.

Optical spectroscopy and optical waveguide fabrication in Eu3+ and Eu3+/Tb3+ doped zinc–sodium–aluminosilicate glasses

International Nuclear Information System (INIS)

Caldiño, U.; Speghini, A.; Berneschi, S.; Bettinelli, M.; Brenci, M.; Pasquini, E.; Pelli, S.; Righini, G.C.

2014-01-01

Optical and spectroscopic properties of 2.0% Eu(PO 3 ) 3 singly doped and 5.0% Tb(PO 3 ) 3 –2.0% Eu(PO 3 ) 3 codoped zinc–sodium–aluminosilicate glasses were investigated. Reddish-orange light emission, with x=0.64 and y=0.36 CIE1931 chromaticity coordinates, is obtained in the europium singly doped glass excited at 393 nm. Such chromaticity coordinates are close to those (0.67,0.33) standard of the National Television System Committee for the red phosphor. When the sodium–zinc–aluminosilicate glass is co-doped with Tb 3+ and Eu 3+ , reddish-orange light emission, with (0.61,0.37) CIE1931 chromaticity coordinates, is obtained upon Tb 3+ excitation at 344 nm. This reddish-orange luminescence is generated mainly by 5 D 0 → 7 F 1 and 5 D 0 → 7 F 2 emissions of Eu 3+ , europium being sensitized by terbium through a non-radiative energy transfer. From an analysis of the Tb 3+ emission decay curves it is inferred that the Tb 3+ →Eu 3+ energy transfer might take place between Tb 3+ and Eu 3+ clusters through a short-range interaction mechanism, so that an electric dipole–quadrupole interaction appears to be the most probable transfer mechanism. The efficiency of this energy transfer is about 62% upon excitation at 344 nm. In the singly doped and codoped glasses multimode optical waveguides were successfully produced by Ag + –Na + ion exchange, and they could be characterized at various wavelengths. -- Highlights: • Reddish-orange light emission can be generated from Tb 3+ and Eu 3+ codoped zinc–sodium–aluminosilicate glasses excited at 344 nm. • The Eu 3+ is sensitized by Tb 3+ through a non-radiative energy transfer. • Highly multimode waveguides can be fabricated by diluted silver–sodium exchange. • This type of AlGaN LEDs pumped glass phosphors might be useful for generation of reddish-orange light

Sodium fire protection

International Nuclear Information System (INIS)

Raju, C.; Kale, R.D.

1979-01-01

Results of experiments carried out with sodium fires to develop extinguishment techniques are presented. Characteristics, ignition temperature, heat evolution and other aspects of sodium fires are described. Out of the powders tested for extinguishment of 10 Kg sodium fires, sodium bi-carbonate based dry chemical powder has been found to be the best extinguisher followed by large sized vermiculite and then calcium carbonate powders distributed by spray nozzles. Powders, however, do not extinguish large fires effectively due to sodium-concrete reaction. To control large scale fires in a LMFBR, collection trays with protective cover have been found to cause oxygen starvation better than flooding with inert gas. This system has an added advantage in that there is no damage to the sodium facilities as has been in the case of powders which often contain chlorine compounds and cause stress corrosion cracking. (M.G.B.)

Kinetics of the Carbonate Leaching for Calcium Metavanadate

Directory of Open Access Journals (Sweden)

Peiyang Shi

2016-10-01

Full Text Available The sodium salt roasting process was widely used for extracting vanadium due to its high yield rate of vanadium. However, the serious pollution was a problem. The calcium roasting process was environmentally friendly, but the yield rate of vanadium was relatively lower. Focusing on the calcium metavanadate produced in the calcium roasting process of vanadium minerals, the mechanism of the carbonate leaching for calcium metavanadate and its leaching kinetics of calcium metavanadate were studied. With the increase of the leaching agent content, the decrease of the particle size, the increase of the temperature and the increase of the reaction time, the leaching rate of vanadium increased, and the constant of reaction rate increased. In the carbonate leaching process, the calcium carbonate was globular and attached to the surface of calcium metavanadate. In the solution containing bicarbonate radical, lots of cracks formed in the dissolution process. However, the cracks were relatively fewer in the solution containing carbonate. In the present study, the carbonate leaching for calcium metavanadate was controlled by diffusion, the activation energy reached maximum and minimum in the sodium bicarbonate and the sodium carbonate solution, respectively. The activation energy value in the ammonium bicarbonate solution was between those two solutions. The kinetic equations of the carbonate leaching for calcium metavanadate were as follows: 1 − 2/3η − (1 − η2/3 = 4.39[Na2CO3]0.75/r0 × exp(−2527.06/Tt; 1 − 2/3η − (1 − η2/3 = 7.89[NaHCO3]0.53/r0 × exp(−2530.67/Tt; 1 − 2/3η − (1 − η2/3 = 6.78[NH4HCO3]0.69/r0 × exp(−2459.71/Tt.

Effect of Calcium Nitrate and Sodium Nitrite on the Rebar Corrosion of Medium Carbon Steel in Seawater and Cassava Fluid

OpenAIRE

Adamu, M; Umoru, LE; Ige, OO

2014-01-01

Inhibitors are regularly used as one of the principal prevention and control techniques in reinforcement corrosion. Hence this study investigates the effect of calcium nitrate and sodium nitrite inhibitors on the rebar corrosion of medium carbon steel in seawater and cassava fluid with a view to determining inhibitive potentials of the different inhibitors in the two media. Gravimetric and voltametric techniques were employed in this study and a total of forty-five corrosion coupons of differ...

Exploratory randomised controlled clinical study to evaluate the comparative efficacy of two occluding toothpastes - a 5% calcium sodium phosphosilicate toothpaste and an 8% arginine/calcium carbonate toothpaste - for the longer-term relief of dentine hypersensitivity.

Science.gov (United States)

Hall, Claire; Mason, Stephen; Cooke, Jonathan

2017-05-01

To compare the longer-term clinical efficacy of two occlusion-technology toothpastes - a 5% calcium sodium phosphosilicate (CSPS) toothpaste and a commercially available 8% arginine/calcium carbonate toothpaste - in relieving dentine hypersensitivity (DH). Efficacy was also compared with that of a regular fluoride toothpaste control. This was an exploratory, randomised, examiner-blind, parallel-group, 11-week, controlled study in healthy adults with self-reported and clinically diagnosed DH. After an acclimatisation period, subjects were randomised to one of three study treatments with which they brushed their teeth twice daily. Sensitivity was assessed at baseline and after 1, 2, 4, 6 and 11 weeks treatment in response to evaporative (air) and tactile stimuli (measured by the Schiff Sensitivity Scale/visual analogue scale and tactile threshold, respectively). A total of 135 subjects were randomised to treatment. The two occlusion-technology toothpastes performed similarly over the 11-week treatment period. All study treatments showed statistically significant reductions from baseline in DH at all timepoints for all measures (pcarbonate anti-sensitivity toothpaste provided similar benefits. Improvements in DH continued throughout the 11-week study. Dentine hypersensitivity (DH) is a common and painful condition. Twice-daily use of a 5% calcium sodium phosphosilicate toothpaste reduces DH within 1-2 weeks of initiating use. Ongoing, twice daily use of the sensitivity toothpastes evaluated in this study was associated with continued, clinically significant improvements in DH. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Angiotensin effects on calcium and steroidogenesis in adrenal glomerulosa cells

International Nuclear Information System (INIS)

Elliott, M.E.; Siegel, F.L.; Hadjokas, N.E.; Goodfriend, T.L.

1985-01-01

We investigated the role of cellular calcium pools in angiotensin II-stimulated aldosterone synthesis in bovine adrenal glomerulosa cells. Angiotensin II decreased the size of the exchangeable cell calcium pool by 34%, consistent with previous observations that angiotensin II causes decreased uptake of 45 Ca+2 into cells and increased efflux of 45 Ca+2 from preloaded cells. Atomic absorption spectroscopy showed that angiotension II caused a decrease of 21% in total cellular calcium. Angiotensin II caused efflux of 45 Ca+2 in the presence of EGTA and retarded uptake of 45 Ca+2 when choline was substituted for sodium, suggesting that hormone effects on calcium pools do not involve influx of trigger calcium or sodium. Cells incubated in calcium-free buffer and 0.1 mM or 0.5 mM EGTA synthesized reduced (but still significant) amounts of the steroid in response to hormone. Cells incubated in increasing concentrations of extracellular calcium contained increasing amounts of intracellular calcium and synthesized increasing amounts of aldosterone in response to angiotensin II. These results point to the participation of intracellular calcium pools in angiotensin II-stimulated steroidogenesis and the importance of extracellular calcium in maintaining these pools

Influence of injected caffeine on the metabolism of calcium and the retention and excretion of sodium, potassium, phosphorus, magnesium, zinc and copper in rats.

Science.gov (United States)

Yeh, J K; Aloia, J F; Semla, H M; Chen, S Y

1986-02-01

Mineral metabolism was studied by the metabolic balance technique in rats with and without administration of caffeine. Caffeine was injected subcutaneously each day at either 2.5 mg or 10 mg/100 g body weight for 2 wk before the balance studies. Urinary volume excretion was higher in the group given caffeine than in the control group, but the creatinine clearance was not different. Urinary excretion of potassium, sodium, inorganic phosphate, magnesium and calcium, but not of zinc and copper, was also higher in the rats given caffeine. The rank order of the difference was the same as the percent of ingested mineral excreted in urine in the absence of caffeine. Caffeine caused a negative balance of potassium, sodium and inorganic phosphate. There was no significant difference from the control levels and in the apparent metabolic balance of calcium and magnesium. The urinary and fecal excretion of zinc and copper were found to be unaffected by caffeine. It is suggested that chronic administration of caffeine may lead to a tendency toward deficiency of those minerals that are excreted primarily in urine.

The influence of calcium-45 on the inhibitive effect of calcium hexameta-phosphate combination and the electrocapillary effect of calcium-45

International Nuclear Information System (INIS)

Subramanyan, N.; Venkatakrishna Iyer, S.; Kapali, V.

1978-01-01

Corrosion of steel in an aqueous chloride solution is significantly accelerated if calcium (NaHMP)-45 is substituted for ordinary calcium when calcium and sodium metaphosphate combination was investigated for inhibiting action. In this investigation it is seen that the anodic polarisation of steel is brought down when 45 Ca is present in the different solutions containing Ca, non radioactive calcium and (NaHMP) at pH 5.5, 7.5 and 9.0 except in one case when 45 Ca is present alone in the solution of pH 5.5. The uptake of 45 Ca is more at the positive potentials than at the negative. Electrocapillary measurements with calcium chloride solution show that the electrocapillary curve is lifted above that for the base solution particularly on the positive side of the electrocapillary maximum. These interesting observations are explained by the postulate that radioactive calcium behaves like an anion and the acceleration of corrosion is attributed essentially to radiolytically produced hydrogen peroxide. (author)

Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Santaquiteria, C., E-mail: ruiz.cs@ietcc.csic.es [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain); Skibsted, J. [Instrument Centre for Solid-State NMR Spectroscopy, Interdisciplinary Nanoscience Center (iNANO), Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Fernandez-Jimenez, A.; Palomo, A. [Eduardo Torroja Institute (CSIC), c/Serrano Galvache, n Degree-Sign 4, 28033 Madrid (Spain)

2012-09-15

This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

Reduction of sodium and increment of calcium and ω-3 polyunsaturated fatty acids in dry fermented sausages: effects on the mineral content, lipid profile and sensory quality.

Science.gov (United States)

García-Íñiguez de Ciriano, Mikel; Berasategi, Izaskun; Navarro-Blasco, Iñigo; Astiasarán, Iciar; Ansorena, Diana

2013-03-15

A combined technological approach was applied in the development of healthier dry fermented sausages: a partial substitution of the pork back fat by pre-emulsified linseed oil and a partial replacement of sodium chloride with calcium ascorbate at two different levels, leading to low amounts of salt (14gSalt and 10gSalt, with 14 g and 10 g NaCl per kg of mixture, respectively). The developed products (14gSalt and 10gSalt) showed adequate results for a(w) (0.85 and 0.87) and pH (4.98 and 5.21), and low lipid oxidation values (1.4 × 10(-4) and 1.5 × 10(-5) g malondialdehyde (MDA) kg(-1)). The lipid modification led to a significantly higher supply of ω-3 (23.3 g kg(-1) ) compared to the control (3.2 g kg(-1) ). Simultaneously, reductions of 38% and 50% in sodium content and a calcium supply of 4 and 5.2 g kg(-1) were achieved in the 14gSalt and 10gSalt formulations, respectively, compared to the control products (26 g salt and 0.87 g kg(-1) Ca). Instrumental analysis of colour and texture and sensory studies demonstrated that the organoleptic quality of the new formulations was similar to that of traditional products. The developed dry fermented sausages showed healthier properties than traditional ones owing to their reduced sodium and higher calcium content and a significant supply of ω-3 fatty acids. © 2012 Society of Chemical Industry.

Diuretics and disorders of calcium homeostasis.

Science.gov (United States)

Grieff, Marvin; Bushinsky, David A

2011-11-01

Diuretics commonly are administered in disorders of sodium balance. Loop diuretics inhibit the Na-K-2Cl transporter and also increase calcium excretion. They are often used in the treatment of hypercalcemia. Thiazide diuretics block the thiazide-sensitive NaCl transporter in the distal convoluted tubule, and can decrease calcium excretion. They are often used in the treatment of nephrolithiasis. Carbonic anhydrase inhibitors decrease bicarbonate absorption and the resultant metabolic acidosis can increase calcium excretion. Their use can promote nephrocalcinosis and nephrolithiasis. This review will address the use of diuretics on disorders of calcium homeostasis. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension

Science.gov (United States)

Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)

1992-01-01

The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

Potassium/sodium ion exchange of sodium aluminosilicate and soda-lime glasses with potassium nitrate melts

International Nuclear Information System (INIS)

Richter, E.

1983-08-01

The alkali self-diffusion coefficients, the concentration-dependent interdiffusion coefficients, and the actual equilibrium constants of the ion exchange process were determinated for model glasses of the Na 2 O-Al 2 O 3 -SiO 2 type and the Na 2 O-CaO-SiO 2 type by nuclear techniques. The measured self-diffusion data and interdiffusion coefficients were used to estimate the stress profiles initiated by the K/Na exchange below the transformation temperature in the surface region. The activation volume of the sodium and potassium ions for diffusion through the surface zone stressed by ion exchange was determined. The disturbing influence of small concentrations of determined divalent cations in KNO 3 (especially Ca 2+ ) was investigated and thermodynamically described. Possibilities were demonstrated to remove these disturbances by anionic admixtures to the KNO 3 melt. Conclusions were drawn for the technical process of the chemical strengthening of glass by K/Na ion exchange at lower temperatures. (author)

Origins of saccharide-dependent hydration at aluminate, silicate, and aluminosilicate surfaces.

Science.gov (United States)

Smith, Benjamin J; Rawal, Aditya; Funkhouser, Gary P; Roberts, Lawrence R; Gupta, Vijay; Israelachvili, Jacob N; Chmelka, Bradley F

2011-05-31

Sugar molecules adsorbed at hydrated inorganic oxide surfaces occur ubiquitously in nature and in technologically important materials and processes, including marine biomineralization, cement hydration, corrosion inhibition, bioadhesion, and bone resorption. Among these examples, surprisingly diverse hydration behaviors are observed for oxides in the presence of saccharides with closely related compositions and structures. Glucose, sucrose, and maltodextrin, for example, exhibit significant differences in their adsorption selectivities and alkaline reaction properties on hydrating aluminate, silicate, and aluminosilicate surfaces that are shown to be due to the molecular architectures of the saccharides. Solid-state (1)H, (13)C, (29)Si, and (27)Al nuclear magnetic resonance (NMR) spectroscopy measurements, including at very high magnetic fields (19 T), distinguish and quantify the different molecular species, their chemical transformations, and their site-specific adsorption on different aluminate and silicate moieties. Two-dimensional NMR results establish nonselective adsorption of glucose degradation products containing carboxylic acids on both hydrated silicates and aluminates. In contrast, sucrose adsorbs intact at hydrated silicate sites and selectively at anhydrous, but not hydrated, aluminate moieties. Quantitative surface force measurements establish that sucrose adsorbs strongly as multilayers on hydrated aluminosilicate surfaces. The molecular structures and physicochemical properties of the saccharides and their degradation species correlate well with their adsorption behaviors. The results explain the dramatically different effects that small amounts of different types of sugars have on the rates at which aluminate, silicate, and aluminosilicate species hydrate, with important implications for diverse materials and applications.

Source fabrication and lifetime for Li⁺ ion beams extracted from alumino-silicate sources

Energy Technology Data Exchange (ETDEWEB)

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W

2012-03-05

A space-charge-limited beam with current densities (J) exceeding 1 mA/cm² have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm², and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

Source fabrication and lifetime for Li⁺ ion beams extracted from alumino-silicate sources

Energy Technology Data Exchange (ETDEWEB)

Roy, Prabir K.; Greenway, Wayne G.; Kwan, Joe W.

2012-04-01

A space-charge-limited beam with current densities (J) exceeding 1 mA/cm² have been measured from lithium alumino-silicate ion sources at a temperature of ~1275 °C. At higher extraction voltages, the source appears to become emission limited with J ≥ 1.5 mA/cm², and J increases weakly with the applied voltage. A 6.35 mm diameter source with an alumino-silicate coating, ≤0.25 mm thick, has a measured lifetime of ~40 h at ~1275 °C, when pulsed at 0.05 Hz and with pulse length of ~6 μs each. At this rate, the source lifetime was independent of the actual beam charge extracted due to the loss of neutral atoms at high temperature. Finally, the source lifetime increases with the amount of alumino-silicate coated on the emitting surface, and may also be further extended if the temperature is reduced between pulses.

Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells

Directory of Open Access Journals (Sweden)

C. H. Yeo

2012-03-01

Full Text Available Calcium phosphate (CaP nanoshells were prepared using negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA as a template by base titration synthesis at various concentrations of NaOH and calcium ions. The elemental composition, morphology, particle size, particle size distribution and zeta potential of the products were determined via various characterisation techniques, such as energy-dispersive X-ray spectrometry (EDX, transmission electron microscopy (TEM, dynamic light scattering (DLS, laser Doppler velocimetry (LDV and Fourier transform infrared spectroscopy (FTIR. The best results showed that stable spherical CaP nanoshells with a mean particle size of 197.5 ± 5.8 nm and a zeta potential of -34.5 ± 0.6 mV were successfully formed when 0.100 M sodium hydroxide (NaOH and 0.100 M calcium ions were used. Moreover, an optimal pH of 10.52 and a final Ca/P molar ratio of 0.97 were achieved under these conditions.

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

Science.gov (United States)

2010-07-01

...-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium salt. 721.2076 Section 721...-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium potassium sodium... identified as D-Glucuronic acid, polymer with 6-deoxy-L-mannose and D-glucose, acetate, calcium magnesium...

Interaction of calcium oxide with molten alkali metal chlorides

International Nuclear Information System (INIS)

Volkovich, A.V.; Zhuravlev, V.I.; Ermakov, D.S.; Magurina, M.V.

1999-01-01

Calcium oxide solubility in molten lithium, sodium, potassium, cesium chlorides and their binary mixtures is determined in a temperature range of 973-1173 K by the method of isothermal saturation. Mechanisms of calcium oxide interaction with molten alkali metal chlorides are proposed

A comparative clinical study investigating the efficacy of a test dentifrice containing 8% strontium acetate and 1040 ppm sodium fluoride versus a marketed control dentifrice containing 8% arginine, calcium carbonate, and 1450 ppm sodium monofluorophosphate in reducing dentinal hypersensitivity.

Science.gov (United States)

Hughes, Nathan; Mason, Stephen; Jeffery, Peter; Welton, Helen; Tobin, Maira; O'Shea, Caoimhe; Browne, Mairead

2010-01-01

The objective of this clinical study was to evaluate and compare the efficacy in reducing dentin hypersensitivity of an 8% strontium acetate, 1040 ppm sodium fluoride dentifrice to a marketed control 8% arginine, calcium carbonate, 1450 ppm sodium monofluorophosphate dentifrice after twice-daily brushing for two, four, and eight weeks. This was a randomized, examiner-blind, two-arm parallel group, eight-week longitudinal clinical study with seventy-nine subjects, stratified based on baseline tooth sensitivity (Schiff score, Yeaple). Subjects brushed with either an 8% strontium acetate-based dentifrice or a marketed 8% arginine calcium carbonate dentifrice twice daily for approximately one minute. At screening, baseline, weeks two, four, and eight, subjects' tooth sensitivity was determined through both evaporative (Schiff and Visual Analogue Scale [VAS]) and tactile stimuli (Yeaple probe). Subject assessments using each stimulus were performed by the same examiner throughout the study. Seventy-seven subjects completed this clinical study. Both subject groups exhibited significant cumulative reductions from baseline to Days 14, 28, and 56 in dentin hypersensitivity as measured by Schiff, Yeaple, and VAS (for the 8% strontium acetate group, p carbonate group, p = 0.0031 for Yeaple at Day 14, p = 0.0015 for VAS at Day 14, and p 0.05) were observed between treatments for any of the time points and measures except for tactile sensitivity at Day 56, for which the 8% strontium acetate-based dentifrice was statistically superior (p = 0.0391) to the control 8% arginine calcium carbonate dentifrice. The 8% strontium acetate, 1040 ppm sodium fluoride dentifrice provided significant reductions in dentin hypersensitivity (p carbonate dentifrice showed no significant differences (p > 0.05) apart from tactile (Yeaple) sensitivity at week 8, where the 8% strontium acetate-based dentifrice showed significant improvement over the control (p = 0.0391).

Hemodialysis for near-fatal sodium phosphate toxicity in a child receiving sodium phosphate enemas.

Science.gov (United States)

Becknell, Brian; Smoyer, William E; O'Brien, Nicole F

2014-11-01

This study aimed to demonstrate the importance of considering hemodialysis as a treatment option in the management of sodium phosphate toxicity. This is a case report of a 4-year-old who presented to the emergency department with shock, decreased mental status, seizures, and tetany due to sodium phosphate toxicity from sodium phosphate enemas. Traditional management of hyperphosphatemia with aggressive hydration and diuretics was insufficient to reverse the hemodynamic and neurological abnormalities in this child. This is the first report of the use of hemodialysis in a child without preexisting renal failure for the successful management of near-fatal sodium phosphate toxicity. Hemodialysis can safely be used as an adjunctive therapy in sodium phosphate toxicity to rapidly reduce serum phosphate levels and increase serum calcium levels in children not responding to conventional management.

Investigation of Al–O–Al sites in an Na-aluminosilicate glass

Indian Academy of Sciences (India)

Unknown

Despite 17OMAS NMR spectra of the sample in both fields do not give much information about the ... not be enough alkali or alkaline earth oxides for charge balancing to ... Although oxygen is the most abundant element in the aluminosilicates ...

A new quantification method based on SEM-EDS to assess fly ash composition and study the reaction of its individual components in hydrating cement paste

Energy Technology Data Exchange (ETDEWEB)

Durdziński, Paweł T., E-mail: pawel.durdzinski@gmail.com [Laboratory of Construction Materials, École Polytechnique Fédérale de Lausanne (EPFL), Station 12, CH-1015 Lausanne (Switzerland); Dunant, Cyrille F. [Laboratory of Construction Materials, École Polytechnique Fédérale de Lausanne (EPFL), Station 12, CH-1015 Lausanne (Switzerland); Haha, Mohsen Ben [HeidelbergCement Technology Center GmbH (HeidelbergCement AG), Rohrbacher Str. 95, 69181 Leimen (Germany); Scrivener, Karen L. [Laboratory of Construction Materials, École Polytechnique Fédérale de Lausanne (EPFL), Station 12, CH-1015 Lausanne (Switzerland)

2015-07-15

Calcareous fly ashes are high-potential reactive residues for blended cements, but their qualification and use in concrete are hindered by heterogeneity and variability. Current characterization often fails to identify the dominant, most reactive, amorphous fraction of the ashes. We developed an approach to characterize ashes using electron microscopy. EDS element composition of millions of points is plotted in a ternary frequency plot. A visual analysis reveals number and ranges of chemical composition of populations: silicate, calcium-silicate, aluminosilicate, and calcium-rich aluminosilicate. We quantified these populations in four ashes and followed their hydration in two Portland-ash systems. One ash reacted at a moderate rate: it was composed of 70 vol.% of aluminosilicates and calcium-silicates and reached 60% reaction at 90 days. The other reacted faster, reaching 60% at 28 days due to 55 vol.% of calcium-rich aluminosilicates, but further reaction was slower and 15 vol.% of phases, the silica-rich ones, did not react.

A new quantification method based on SEM-EDS to assess fly ash composition and study the reaction of its individual components in hydrating cement paste

International Nuclear Information System (INIS)

Durdziński, Paweł T.; Dunant, Cyrille F.; Haha, Mohsen Ben; Scrivener, Karen L.

2015-01-01

Calcareous fly ashes are high-potential reactive residues for blended cements, but their qualification and use in concrete are hindered by heterogeneity and variability. Current characterization often fails to identify the dominant, most reactive, amorphous fraction of the ashes. We developed an approach to characterize ashes using electron microscopy. EDS element composition of millions of points is plotted in a ternary frequency plot. A visual analysis reveals number and ranges of chemical composition of populations: silicate, calcium-silicate, aluminosilicate, and calcium-rich aluminosilicate. We quantified these populations in four ashes and followed their hydration in two Portland-ash systems. One ash reacted at a moderate rate: it was composed of 70 vol.% of aluminosilicates and calcium-silicates and reached 60% reaction at 90 days. The other reacted faster, reaching 60% at 28 days due to 55 vol.% of calcium-rich aluminosilicates, but further reaction was slower and 15 vol.% of phases, the silica-rich ones, did not react

Comprehensive Study of the Solubility, Thermochemistry, Ion Exchange, and Precipitation Kinetics of NO3 Cancrinite and NO3 Sodalite

International Nuclear Information System (INIS)

Navrotsky, Alexandra; Liu, Qinyuan

2004-01-01

The precipitation of aluminosilicate phases from caustic nuclear wastes has proven to be problematic in a number of processes including radionuclide separations (cementation of columns by aluminosilicate phases), tank emptying (aluminosilicate tank heels), and condensation of wastes in evaporators (aluminosilicate precipitates in the evaporators, providing nucleation sites for growth of critical masses of radioactive actinide salts). In a collaboration between SNL and UCD, we have investigated why and how these phases form, and which conditions favor the formation of which phases. These studies have involved synthesis and characterization of aluminosilicate phases formed using a variety of synthesis techniques, kinetics of precipitation, structural investigations of aluminosilicate phases, thermodynamic calculations of aluminosilicate solubility, calorimetric studies of aluminosilicate precipitation, and a limited investigation of radionuclide partitioning and ion exchange processes (involving typical tank fluid chemistries and these materials). The predominant phases that are observed in the aluminosilicate precipitates from basic tanks wastes (i.e. Hanford, Savannah River Site ''SRS'' wastes) are the salt enclathrated zeolites: sodium nitrate, sodium carbonate and sodium hydroxide sodalite and cancrinite. These phases precipitate readily from the high ionic strength, highly basic solutions at ambient temperatures as well as at elevated temperatures, with or without the presence of an external Al and Si source (both are contained in the waste solutions), and upon interactions with reactive soil components such as clays

THERMAL DEGRADATION AND FLAME RETARDANCY OF CALCIUM ALGINATE FIBERS

Institute of Scientific and Technical Information of China (English)

于建; 夏延致

2009-01-01

Calcium alginate fibers were prepared by wet spinning of sodium alginate into a coagulating bath containing calcium chloride.The thermal degradation and flame retardancy of calcium alginate fibers were investigated with thermal gravimetry(TG),X-ray diffraction(XRD),limiting oxygen index(LOI) and cone calorimeter(CONE).The results show that calcium alginate fibers are inherently flame retardant with a LOI value of 34,and the heat release rate(HRR),total heat release(THR),CO and CO_2 concentrations during ...

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

International Nuclear Information System (INIS)

Wilmarth, W.R.; Rosencrance, S.W.; Nash, C.A.; Fonduer, F.F.; Di Pirete, D.P.; Di Prete, C.C.

2000-01-01

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

Excretion of Calcium, Phosphorus, Magnesium and Sodium in Lactating Sows

Directory of Open Access Journals (Sweden)

Novotný J.

2016-06-01

Full Text Available The aim of this study was to evaluate the excretion of calcium (Ca, phosphorus (P, magnesium (Mg and sodium (Na via milk, urine and faeces during the lactation period of sows. Six clinically healthy lactating sows (crossbreed Large White × Landrace were selected for these experiments and were housed in standard conditions and fed with commercially prepared dry mixture for this category of sows. The blood serum, milk, urine and faecal samples were collected on the 7th, 14th, 21st, and 28th day of lactation. During four weeks of lactation, we recorded the relatively stable and physiological concentrations of Ca, P, Mg and Na in blood serum. The analysis of the sow’s milk showed the highest concentration of Ca and P at the end of lactation, while the highest concentration of Mg and Na was observed on the 7th lactation day. The following macro-mineral excretion was recorded in urine: 98.83-194.00 mg.l-1 for Ca; 11.88- 53.09 mg.l-1 for P; 171.67-344.05 mg.l-1 for Mg; and 56.50-74.83 mg.l-1 for Na; and in the faeces, 1824.5- 3045.5 mg.kg-1 for Ca; 1566.93-2483.2 mg.kg-1 for P; 1916.2-2505.2 mg.kg-1 for Mg; and 516.8-748.2 mg. kg-1 for Na.

Mechanical Properties and Durability of Advanced Environmental Barrier Coatings in Calcium-Magnesium-Alumino-Silicate Environments

Science.gov (United States)

Miladinovich, Daniel S.; Zhu, Dongming

2011-01-01

Environmental barrier coatings are being developed and tested for use with SiC/SiC ceramic matrix composite (CMC) gas turbine engine components. Several oxide and silicate based compositons are being studied for use as top-coat and intermediate layers in a three or more layer environmental barrier coating system. Specifically, the room temperature Vickers-indentation-fracture-toughness testing and high-temperature stability reaction studies with Calcium Magnesium Alumino-Silicate (CMAS or "sand") are being conducted using advanced testing techniques such as high pressure burner rig tests as well as high heat flux laser tests.

A Double-Blind, Active-Controlled Clinical Trial of Sodium Bicarbonate and Calcium Gluconate in the Treatment of Bilateral Osteoarthritis of the Knee

Directory of Open Access Journals (Sweden)

María del Carmen Caamaño

2017-02-01

Full Text Available Objective: To evaluate the effect of intra-articular injections of sodium bicarbonate with a single (SBCG1 or double dose (SBCG2 of calcium gluconate administered monthly compared with methylprednisolone (MP for treatment of knee osteoarthritis. Methods: A 3-month, randomized, double-blind clinical trial with patients diagnosed with knee osteoarthritis (OA. The outcome variables were the Western Ontario-McMaster University Osteoarthritis Index (WOMAC and the Lequesne functional index. Results: After 3 months, all treatments significantly improved in overall WOMAC and Lequesne scores. Mean changes (95% confidence interval in WOMAC total score and the Lequesne index, respectively, for SBCG1 (−12.5 [−14.3, −10.7]; −9.0 [−11.4, −6.7] and SBCG2 (−12.3 [−14.3, −10.4]; −8.9 [−10.4, −7.4] were significantly greater than for MP (−5.0 [−7.2, −2.8]; −3.2 [−4.9, −1.5] ( P  < .001. Conclusions: Intra-articular injections of sodium bicarbonate and calcium gluconate are useful for short-term relief of OA symptoms in patients with bilateral knee osteoarthritis. Both treatments are more effective than MP injections in the reduction of knee OA symptoms. Trial Registration: Clinicaltrials.gov NCT00977444

3D printing of mineral-polymer bone substitutes based on sodium alginate and calcium phosphate.

Science.gov (United States)

Egorov, Aleksey A; Fedotov, Alexander Yu; Mironov, Anton V; Komlev, Vladimir S; Popov, Vladimir K; Zobkov, Yury V

2016-01-01

We demonstrate a relatively simple route for three-dimensional (3D) printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP) for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the "ink"). The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm) and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

Synthesis of calcium hydroxyapatite from calcium carbonate and different orthophosphate sources: A comparative study

International Nuclear Information System (INIS)

Pham Minh, Doan; Lyczko, Nathalie; Sebei, Haroun; Nzihou, Ange; Sharrock, Patrick

2012-01-01

Highlights: ► Calcium hydroxyapatite was synthesized from CaCO 3 and four orthophosphates. ► Only H 3 PO 4 led to the complete precipitation of orthophosphate species. ► H 3 PO 4 was also the most efficient for calcium dissolution. ► Reaction pathway was dissolution-precipitation accompanied by agglomeration step. - Abstract: The synthesis of calcium hydroxyapatite (Ca-HA) starting from calcium carbonate and different orthophosphate sources, including orthophosphoric acid, potassium, sodium and ammonium dihydrogen orthophosphates, was investigated under ambient conditions. The reaction started with calcium carbonate dissolution in an acid medium, followed by rapid precipitation of calcium cations with orthophosphate species to form calcium phosphate based particles which were in the size range of 0.4–1 μm. These particles then agglomerated into much larger ones, up to 350 μm in diameter (aggregates). These aggregates possessed an unstable porous structure which was responsible for the porosity of the final products. The highest specific surface area and pore volume were obtained with potassium dihydrogen orthophosphate. On the other hand, orthophosphoric acid led to the highest dissolution of calcium carbonate and the complete precipitation of orthophosphate species. Under ambient conditions, calcium phosphate based solid products of low crystallinity were formed. Different intermediates were identified and a reaction pathway proposed.

Optimization of diclofenac sodium profile from halloysite nanotubules.

Science.gov (United States)

Krejčová, Kateřina; Deasy, Patrick B; Rabišková, Miloslava

2013-04-01

Halloysite, aluminosilicate clay with the particle shape of multilayered hollow nanotubes, used in various non-medical applications, e.g. in ceramic industry, was discovered for pharmaceutical purposes in recent years. Several drugs of hydrophilic and lipophilic nature have been successfully encapsulated into halloysite tubules in order to modify their dissolution profile. The main goal of this experiment was to optimize the dissolution profile of diclofenac sodium - a drug with problematic solubility - from halloysite tubules using various polymers. Loading of the drug together with povidone or Eudragit® RS did not lead to drug burst effect reduction and its slower dissolution. In the case of povidone, drug improved wettability and solubilization rather than viscosity increasing expectations were observed. Eudragit® RS formed a solid dispersion with diclofenac sodium and thus the solvent/drug solution penetration through the polymer and not the drug solubility was the dissolution rate limiting factor. Reduction of the burst effect and further prolongation of drug release was achieved by coating the drug-loaded halloysite with chitosan. This formulation exhibited a diffusion-controlled prolonged release following Higuchi kinetic model.

Thermodynamics of manganese oxides: Sodium, potassium, and calcium birnessite and cryptomelane

Science.gov (United States)

Birkner, Nancy; Navrotsky, Alexandra

2017-01-01

Manganese oxides with layer and tunnel structures occur widely in nature and inspire technological applications. Having variable compositions, these structures often are found as small particles (nanophases). This study explores, using experimental thermochemistry, the role of composition, oxidation state, structure, and surface energy in the their thermodynamic stability. The measured surface energies of cryptomelane, sodium birnessite, potassium birnessite and calcium birnessite are all significantly lower than those of binary manganese oxides (Mn3O4, Mn2O3, and MnO2), consistent with added stabilization of the layer and tunnel structures at the nanoscale. Surface energies generally decrease with decreasing average manganese oxidation state. A stabilizing enthalpy contribution arises from increasing counter-cation content. The formation of cryptomelane from birnessite in contact with aqueous solution is favored by the removal of ions from the layered phase. At large surface area, surface-energy differences make cryptomelane formation thermodynamically less favorable than birnessite formation. In contrast, at small to moderate surface areas, bulk thermodynamics and the energetics of the aqueous phase drive cryptomelane formation from birnessite, perhaps aided by oxidation-state differences. Transformation among birnessite phases of increasing surface area favors compositions with lower surface energy. These quantitative thermodynamic findings explain and support qualitative observations of phase-transformation patterns gathered from natural and synthetic manganese oxides. PMID:28130549

Intracellular calcium modulates basolateral K(+)-permeability in frog skin epithelium

DEFF Research Database (Denmark)

Brodin, Birger; Rytved, K A; Nielsen, R

1994-01-01

Cytosolic calcium ([Ca2+]i) has been suggested as a key modulator in the regulation of active sodium transport across electrically "tight" (high resistance) epithelia. In this study we investigated the effects of calcium on cellular electrophysiological parameters in a classical model tissue, the...

Properties of Aluminosilicate Refractories with Synthesized Boron-Modified TiO2 Nanocrystals

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Claudia Carlucci

2015-03-01

ture was analysed by Scanning Electron Microscopy (SEM and energy dispersion spectroscopy (EDS. The bricks obtained with nanoadditives presented improved mechanical characteristics with respect to the typical aluminosilicates, presumably because of a better compac‐ tion during the raw materials’ mixing stage.

Environmental effects on fatigue of alkaline earth aluminosilicate glass with varying fictive temperature

DEFF Research Database (Denmark)

Striepe, Simon; Deubener, Joachim; Smedskjær, Morten Mattrup

2013-01-01

The influence of relative humidity on microhardness, stress intensity, crack resistance, and sub-critical crack growth of an alkaline earth aluminosilicate glass has been studied by Vickers indentation. Quenched and annealed glasses with a wide range of fictive temperatures (ΔTf ≈ 130 K) are comp......The influence of relative humidity on microhardness, stress intensity, crack resistance, and sub-critical crack growth of an alkaline earth aluminosilicate glass has been studied by Vickers indentation. Quenched and annealed glasses with a wide range of fictive temperatures (ΔTf ≈ 130 K....... The glasses with lower fictive temperature exhibit a larger change in the micromechanical properties when comparing wet and dry conditions. Finally, it is found that sub-critical crack growth is larger in the low fictive temperature glasses, indicating a diminished resistance against fatigue and stress...

3D printing of mineral–polymer bone substitutes based on sodium alginate and calcium phosphate

Directory of Open Access Journals (Sweden)

Aleksey A. Egorov

2016-11-01

Full Text Available We demonstrate a relatively simple route for three-dimensional (3D printing of complex-shaped biocompatible structures based on sodium alginate and calcium phosphate (CP for bone tissue engineering. The fabrication of 3D composite structures was performed through the synthesis of inorganic particles within a biopolymer macromolecular network during 3D printing process. The formation of a new CP phase was studied through X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Both the phase composition and the diameter of the CP particles depend on the concentration of a liquid component (i.e., the “ink”. The 3D printed structures were fabricated and found to have large interconnected porous systems (mean diameter ≈800 μm and were found to possess compressive strengths from 0.45 to 1.0 MPa. This new approach can be effectively applied for fabrication of biocompatible scaffolds for bone tissue engineering constructions.

Continuous method for refining sodium. [for use in LMFBR type reactors

Energy Technology Data Exchange (ETDEWEB)

Batoux, B; Laurent-Atthalin, A; Salmon, M

1973-11-16

The invention relates to a refining method according to which commercial sodium provides a high purity sodium with, in particular, a very small calcium content. The method consists in continuously feeding a predetermined amount of sodium peroxide into a sodium stream, mixing and causing said sodium peroxide to reach with sodium at an appropriate temperature, and, finally, separating the reaction products from sodium by decanting and filtering same. The thus obtained high purity sodium meets the requirements of atomic industries in particular, in view of its possible use as coolant in nuclear reactors of the ''breeder'' type.

Estimation of ionized calcium, total calcium and albumin corrected calcium for the diagnosis of hypocalcaemia of malignancy

International Nuclear Information System (INIS)

Ijaz, A.; Mehmood, T.; Qureshi, A.H.; Anwar, M.; Dilawar, M.; Hussain, I.; Khan, F.A.; Khan, D.A.; Hussain, S.; Khan, I.A.

2006-01-01

Objective: To measure levels of ionized calcium, total calcium and albumin corrected calcium in patients with different malignant disorders for the diagnosis of hypercalcaemia of malignancy. Design: A case control comparative study. Place and Duration of Study: The study was carried out in the Department of Pathology, Army Medical College Rawalpindi, Armed Forces Institute of Pathology and Department of Oncology CMH, Rawalpindi from March 2003 to December 2003. Subjects and Methods: Ninety-seven patients of various malignant disorders, admitted in the Department of Oncology, CMH, Rawalpindi, and 39 age and gender-matched disease-free persons (as control) were included in the study. Blood ionized calcium (Ca/sup ++/), pH, sodium (Na/sup +/) and potassium (K/sup +/) were analysed by Ion selective electrode (ISE) on Easylyte> auto analyser. Other related parameters were measured by colorimetric methods. Results: Blood Ca/sup ++/ levels in patients suffering from malignant disorders were found significantly high (mean +- j 1.30+017 mmoV/L) as compared to control subjects (mean +- 1.23+0.03 mmoV/L) (p<0.001). The number of patients with hypercalcaemia of malignancy detected by Ca/sup ++/ estimation was significantly higher (38%) as compared to total calcium (8.4%) and albumin corrected calcium ACC (10.6%) (p<0.001). There was no statistically significant difference in other parameters e.g. phosphate, urea, creatinine, pH, Na/sup +/ and K/sup +/ levels in study subjects and controls. Conclusion: Detection of hypercalcaemia can be markedly improved if ionized calcium estimation is used in patients with malignant disorders. (author)

The Role of Calcium in Ameliorating the Oxidative Stress of Fluoride in Rats.

Science.gov (United States)

Mohamed, N E

2016-03-01

The present study was carried out to investigate the effects of fluoride toxicity on some biochemical, hormonal, and histological parameters of female rats and the protective role of calcium against such effects. Adult female albino rats were divided into five groups; control group received distilled water for 60 days, calcium group received calcium carbonate with dose of 50 mg/kg three times per week for 60 days, fluoride group received sodium fluoride with dose of 20 mg/kg three times per week for 60 days, calcium + fluoride group received calcium carbonate (50 mg/kg) then after 2 h received sodium fluoride (20 mg/kg) three times per week for 60 days, and fluoride + calcium group received sodium fluoride (20 mg/kg) three times per week for 30 days then received calcium carbonate (50 mg/kg) three times per week for another 30 days. The results showed that the levels of thiobarbituric acid reactive substances, urea, creatinine, alkaline phosphatase, triiodothyronine, thyroxine, parathormone, phosphorous, magnesium, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and gamma glutamyl transferase were significantly increased in rats treated with fluoride while serum estradiol, calcium, and organ glutathione were significantly decreased. The histological examination of the femur bone revealed that fluoride treatment induced thinning of bone trabeculae with wilding of marrow space, demineralization, and loss of trabeculae interconnections. Also, the histological examination of hepatic and renal tissues of fluoride-treated rats showed some damages in these tissues while administration of calcium carbonate for 30 or 60 days during fluoride treatment minimized such damages. It could be concluded that administration of calcium to female rats can ameliorate the hazardous effects of fluoride observed in the biochemical, hormonal, and histological parameters.

Creating large second-order optical nonlinearity in optical waveguides written by femtosecond laser pulses in boro-aluminosilicate glass

Science.gov (United States)

An, Hong-Lin; Arriola, Alexander; Gross, Simon; Fuerbach, Alexander; Withford, Michael J.; Fleming, Simon

2014-01-01

The thermal poling technique was applied to optical waveguides embedded in a commercial boro-aluminosilicate glass, resulting in high levels of induced second-order optical nonlinearity. The waveguides were fabricated using the femtosecond laser direct-write technique, and thermally poled samples were characterized with second harmonic optical microscopy to reveal the distribution profile of the induced nonlinearity. It was found that, in contrast to fused silica, the presence of waveguides in boro-aluminosilicate glass led to an enhancement of the creation of the second-order nonlinearity, which is larger in the laser written waveguiding regions when compared to the un-modified substrate. The magnitude of the nonlinear coefficient d33 achieved in the core of the laser-written waveguides, up to 0.2 pm/V, was comparable to that in thermally poled fused silica, enabling the realization of compact integrated electro-optic devices in boro-aluminosilicate glasses.

Preparation of Ultra-fine Calcium Carbonate by a Solvent-free ...

African Journals Online (AJOL)

The treatment of calcium chloride with sodium carbonate under solvent-free conditions with a supersonic airflow and at a low heating temperature leads to the synthesis of ultra-fine calcium carbonate. The reaction not only involves mild conditions, a simple operation, and high yields but also gives a high conversion rate.

Influence of sodium, calcium, magnesium, and ammonium in the sorption of cadmium in a zeolite rock

International Nuclear Information System (INIS)

Teutli S, E.A.

2007-01-01

The cadmium is one of the more toxic heavy metals and the water pollution by this metal, is originated by industries whose turn is the production of batteries, electroplating processes, the production of pigments and in the refinement process of others metals. The objective of this work was to evaluate the ion exchange of cadmium using natural zeolite, obtained from the Arroyo zone, La Haciendita Municipality, in the State of Chihuahua. The parameters considered in this investigation were: the sorption time, the pH, the initial concentration of cadmium and the influence of sodium, calcium, magnesium and ammonium on the sorption of cadmium in the natural zeolite. Also, the theoretical pattern for kinetics and isotherm that better it is adjusted to those experimental results it was determined. The experimentation results allowed to establish the following conclusions: the sorption of the cadmium doesn't depend on the pH in an interval between 4 and 6; the pattern that better it describes the kinetics it is that of Pseudo-second order of Ho and Mc Kay; the Langmuir-Freundlich pattern is the one that better it describes the sorption isotherm and the calcium is the component that interferes in an important manner in the sorption of cadmium. The carried out investigation contributes to the definition of some of the parameters that should be considered in the development of ion exchangers for the cadmium removal. (Author)

Improving the desulfurization performance of CaCO3 with sodium humate

Science.gov (United States)

Feng, Run; Sun, Zhiguo; Zhang, Wenqing; Huang, Hao; Hu, Haihang; Zhang, Li; Xie, Hongyong

2018-02-01

The influence of these factors on desulphurization efficiency was studied by changing the amount of calcium carbonate, the concentration of sulfur dioxide, the liquid flow rate of absorbent and the air flow rate, the optimum working condition was determined by the research of limestone-gypsum desulphurization process commonly used in industry. By changing the amount of calcium carbonate, we conclude that the volume of water in the desulfurization efficiency does not increase with the adding amount of calcium carbonate. The optimum conditions were determined : at the condicion of the concentration of 500ppm of sulfur dioxide, 10g calcium carbonate, 150L/h liquid flow and the minimum air flow rate of 6.75m3/h, the highest desulfurization efficiency was close to 100% when sodium humate was not added, but the holding time was only about 5 minutes. After adding 3g of humic acid, the desulfurization efficiency was improved obviously, and the instantaneous efficiency of 100% lasting for about 40 minutes. It can be seen that, calcium carbonate in the addition of humic acid sodium can significantly improve the absorption of calcium carbonate performance of SO2.

Study of the rheological behavior of the calcium and sodium caseinate irradiated dispersions; Estudo dos comportamentos reologicos das dispersoes irradiadas dos caseinatos de calcio e de sodio

Energy Technology Data Exchange (ETDEWEB)

Sabato, Susy Frey [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes]. E-mail: sfsabato@net.ipen.br

2002-07-01

Milk isolated proteins has gained a crescent commercial interest due to functional properties allied to excellent nutritional value. These properties could be improved when some treatments are applied, such as gamma-irradiation, combined or not with plasticizers. In the current work, protein solutions (calcium and sodium caseinates) were mixed with glycerol. The mixtures (8% protein base), at the ratios 1:1 and 2:1 (protein: glycerol) were submitted to gamma-irradiation ({sup 60} Co), in the doses 0 kGy, 5 kGy, 15 kGy and 25 kGy, and the rheological behavior was studied. The irradiation was in a {sup 60} Co source, model Gammacell 220 (AECL), with dose ratio 8.2 kGy/h. The viscosity measurements were made in a Brookfield, model LV-DVIII, spindle SC4-18 and SC4-31, according methodology described previously, at temperature 10.0 deg C {+-} 0,1 deg C, using a Neslab water bath. As irradiation dose increases, the viscosity measurements decrease significantly (p<0.05) for calcium/glycerol solution. The measurements for sodium/glycerol mixtures remained constant as dose irradiation increases, with a slight augmentation at 5 kGy. (author)

Optical spectroscopy and optical waveguide fabrication in Eu{sup 3+} and Eu{sup 3+}/Tb{sup 3+} doped zinc–sodium–aluminosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 México D.F. (Mexico); Speghini, A. [Dipartimento di Biotecnologie, Università di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Berneschi, S. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Bettinelli, M. [Dipartimento di Biotecnologie, Università di Verona and INSTM, UdR Verona, Strada Le Grazie 15, I-37314 Verona (Italy); Brenci, M. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Pasquini, E. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze, Via Sansone 1, 50019 Sesto Fiorentino (Firenze) (Italy); Pelli, S. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Righini, G.C. [Istituto di Fisica Applicata Nello Carrara, C.N.R., Via Madonna del Piano 10, 50019 Sesto Fiorentino (Firenze) (Italy); Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 2, 00184 Roma (Italy)

2014-03-15

Optical and spectroscopic properties of 2.0% Eu(PO{sub 3}){sub 3} singly doped and 5.0% Tb(PO{sub 3}){sub 3}–2.0% Eu(PO{sub 3}){sub 3} codoped zinc–sodium–aluminosilicate glasses were investigated. Reddish-orange light emission, with x=0.64 and y=0.36 CIE1931 chromaticity coordinates, is obtained in the europium singly doped glass excited at 393 nm. Such chromaticity coordinates are close to those (0.67,0.33) standard of the National Television System Committee for the red phosphor. When the sodium–zinc–aluminosilicate glass is co-doped with Tb{sup 3+} and Eu{sup 3+}, reddish-orange light emission, with (0.61,0.37) CIE1931 chromaticity coordinates, is obtained upon Tb{sup 3+} excitation at 344 nm. This reddish-orange luminescence is generated mainly by {sup 5}D{sub 0}→{sup 7}F{sub 1} and {sup 5}D{sub 0} →{sup 7}F{sub 2} emissions of Eu{sup 3+}, europium being sensitized by terbium through a non-radiative energy transfer. From an analysis of the Tb{sup 3+} emission decay curves it is inferred that the Tb{sup 3+}→Eu{sup 3+} energy transfer might take place between Tb{sup 3+} and Eu{sup 3+} clusters through a short-range interaction mechanism, so that an electric dipole–quadrupole interaction appears to be the most probable transfer mechanism. The efficiency of this energy transfer is about 62% upon excitation at 344 nm. In the singly doped and codoped glasses multimode optical waveguides were successfully produced by Ag{sup +}–Na{sup +} ion exchange, and they could be characterized at various wavelengths. -- Highlights: • Reddish-orange light emission can be generated from Tb{sup 3+} and Eu{sup 3+} codoped zinc–sodium–aluminosilicate glasses excited at 344 nm. • The Eu{sup 3+} is sensitized by Tb{sup 3+} through a non-radiative energy transfer. • Highly multimode waveguides can be fabricated by diluted silver–sodium exchange. • This type of AlGaN LEDs pumped glass phosphors might be useful for generation of reddish-orange light.

Effect of fly ash composition on the sulfate resistance of concrete[Includes the CSCE forum on professional practice and career development : 1. international engineering mechanics and materials specialty conference : 1. international/3. coastal, estuarine and offshore engineering specialty conference : 2. international/8. construction specialty conference

Energy Technology Data Exchange (ETDEWEB)

Dhole, R.D.; Thomas, M.D.A. [New Brunswick Univ., Fredericton, NB (Canada); Folliard, K.J.; Drimalas, T. [Texas Univ., Austin, TX (United States)

2009-07-01

Studies have shown that low-calcium Class F fly ashes obtained from burning coal in power stations can increase the sulfate resistance of Portland cement concrete. In many cases the sulfate resistance of concrete containing high-calcium Class C fly ash can be reduced compared to concrete without fly ash, due to the presence of crystalline C3A in the fly ash and calcium aluminate in the glass. This study investigated the differences in the glass composition and sulfate resistance of fly ashes with a range of calcium contents. The objective was to determine whether the behaviour of high-calcium fly ashes could be improved by blending with low-calcium fly ash. The sulfate resistance of cementitious systems consisting of a Type I Portland cement blended with Class F and Class C fly ashes of varying composition was evaluated by monitoring the length change of mortar bars stored in 5 per cent sodium sulfate solution. Scanning electron microscopy and electron dispersive X-ray analysis were used to characterize the glass phases of the fly ashes. The position occupied by the glass when plotted on a CaO-SiO{sub 2}-Al{sub 2}O{sub 3} ternary was identified as belonging to one of the fields occupied by the mineral phases mullite, anorthosite or gehlenite. The glass showed a transition from alumino-silicate in Class F fly ash to a calcium alumino-silicate or mixed calcium-aluminate/alumino-silicate in Class C fly ashes with higher calcium contents. Fly ashes with high amounts of calcium-aluminate glass had reduced sulfate resistance when tested in mortars. Blends of Class C and Class F fly ashes had better sulfate resistance than mixes made with only Class C fly ash. A relationship was established between the calcium oxide content of the blended fly ash and sulfate resistance of mortar. 8 refs., 5 tabs., 10 figs.

Digestion of Alumina from Non-Magnetic Material Obtained from Magnetic Separation of Reduced Iron-Rich Diasporic Bauxite with Sodium Salts

Directory of Open Access Journals (Sweden)

Guanghui Li

2016-11-01

Full Text Available Recovery of iron from iron-rich diasporic bauxite ore via reductive roasting followed by magnetic separation has been explored recently. However, the efficiency of alumina extraction in the non-magnetic materials is absent. In this paper, a further study on the digestion of alumina by the Bayer process from non-magnetic material obtained after magnetic separation of reduced iron-rich diasporic bauxite with sodium salts was investigated. The results indicate that the addition of sodium salts can destroy the original occurrences of iron-, aluminum- and silicon-containing minerals of bauxite ore during reductive roasting. Meanwhile, the reactions of sodium salts with complex aluminum- and silicon-bearing phases generate diaoyudaoite and sodium aluminosilicate. The separation of iron via reductive roasting of bauxite ore with sodium salts followed by magnetic separation improves alumina digestion in the Bayer process. When the alumina-bearing material in bauxite ore is converted into non-magnetic material, the digestion temperature decreases significantly from 280 °C to 240 °C with a nearly 99% relative digestion ratio of alumina.

X-ray Absorption Spectroscopy Identifies Calcium-Uranyl-Carbonate Complexes at Environmental Concentrations

International Nuclear Information System (INIS)

Kelly, Shelly D.; Kemner, Kenneth M.; Brooks, Scott C.

2007-01-01

Current research on bioremediation of uranium-contaminated groundwater focuses on supplying indigenous metal-reducing bacteria with the appropriate metabolic requirements to induce microbiological reduction of soluble uranium(VI) to poorly soluble uranium(IV). Recent studies of uranium(VI) bioreduction in the presence of environmentally relevant levels of calcium revealed limited and slowed uranium(VI) reduction and the formation of a Ca-UO2-CO3 complex. However, the stoichiometry of the complex is poorly defined and may be complicated by the presence of a Na-UO2-CO3 complex. Such a complex might exist even at high calcium concentrations, as some UO2-CO3 complexes will still be present. The number of calcium and/or sodium atoms coordinated to a uranyl carbonate complex will determine the net charge of the complex. Such a change in aqueous speciation of uranium(VI) in calcareous groundwater may affect the fate and transport properties of uranium. In this paper, we present the results from X-ray absorption fine structure (XAFS) measurements of a series of solutions containing 50 lM uranium(VI) and 30 mM sodium bicarbonate, with various calcium concentrations of 0-5 mM. Use of the data series reduces the uncertainty in the number of calcium atoms bound to the UO2-CO3 complex to approximately 0.6 and enables spectroscopic identification of the Na-UO2-CO3 complex. At nearly neutral pH values, the numbers of sodium and calcium atoms bound to the uranyl triscarbonate species are found to depend on the calcium concentration, as predicted by speciation calculations

Estimation of Frost Resistance of the Tile Adhesive on a Cement Based with Application of Amorphous Aluminosilicates as a Modifying Additive

Science.gov (United States)

Ivanovna Loganina, Valentina; Vladimirovna Zhegera, Christina

2017-10-01

In the article given information on the possibility of using amorphous aluminosilicates as a modifying additive in the offered tile cement adhesive. In the article, the data on the preparation of an additive based on amorphous aluminosilicates, on its microstructure and chemical composition. Presented information on the change in the porosity of cement stone when introduced of amorphous aluminosilicates in the his composition. The formulation of a dry building mix on a cement base is proposed with use of an additive based on amorphous aluminosilicates as a modifying additive. Recipe of dry adhesive mixes include Portland cement M400, mineral aggregate in proportion fraction 0.63-0.315:0.315-0.14 respectively 80:20 (%) and filling density of 1538.2 kg/m3, a plasticizer Kratasol, redispersible powder Neolith P4400 and amorphous alumnosilicates. The developed formulation can be used as a tile adhesive for finishing walls of buildings and structure with tiles. Presented results of the evaluation of frost resistance of adhesives based on cement with using of amorphous aluminosilicates as a modifying additive. Installed the mark on the frost resistance of tile glue and frost resistance of the contact zone of adhesive. Established, that the adhesive layer based on developed formulation dry mixture is crack-resistant and frost-resistant for conditions city Penza and dry humidity zone - zone 3 and climatic subarea IIB (accordance with Building codes and regulations 23-01-99Ȋ) cities Russia’s.

Isolation and characterization of Linum usitatisimum polysaccharide to prepare mucoadhesive beads of diclofenac sodium.

Science.gov (United States)

Saquib Hasnain, M; Rishishwar, Poonam; Rishishwar, Sanjay; Ali, Sadath; Nayak, Amit Kumar

2018-05-01

The present research deals with the usefulness of isolated linseed polysaccharide (LP) as polymeric-blends with an anionic polymer, sodium alginate to prepare ionotropically cross-linking gelled mucoadhesive beads for controlled drug release. From the mature and ripe linseeds (Linum usitatisimum; family Liliaceae), LP was isolated and its colour, odour, taste, solubility in water, pH and viscosity were studied. Isolated LP was also characterized by FTIR spectroscopy and 1 H NMR analyses. LP‑calcium alginate beads loaded with diclofenac sodium were formulated via ionotropically crosslinking gelation method using calcium chloride as ionotropic crosslinker. These ionotropically crosslinked beads showed diclofenac sodium encapsulation efficiencies in these newly prepared beads were 60.78 ± 2.47 to 93.16 ± 4.08% and average bead-sizes of 1.17 ± 0.10 to 1.33 ± 0.12 mm. All LP‑calcium alginate beads loaded with diclofenac sodium demonstrated a sustained drug releasing profile over 8 h with a zero-order model of drug releasing (controlled drug releasing pattern). The LP‑calcium alginate beads loaded with diclofenac sodium displayed a pH responsive swelling and excellent biomucoadhesivity prospective with the intestinal mucosal tissue in both the acidic and alkaline pH (pH 1.2 and 7.4, respectively). These beads were also characterized by SEM and FTIR spectroscopy. Copyright © 2017. Published by Elsevier B.V.

Studying inhibition of calcium oxalate stone formation: an in vitro approach for screening hydrogen sulfide and its metabolites

Directory of Open Access Journals (Sweden)

S. Vaitheeswari

2015-06-01

Full Text Available ABSTRACTPurpose:Calcium oxalate urolithiasis is one of the most common urinary tract diseases and is of high prevalence. The present study proposes to evaluate the antilithiatic property of hydrogen sulfide and its metabolites like thiosulfate & sulfate in an in vitro model.Materials and Methods:The antilithiatic activity of sodium hydrogen sulfide (NaSH, sodium thiosulfate (Na2S2O3 and sodium sulfate (Na2SO4 on the kinetics of calcium oxalate crystal formation was investigated both in physiological buffer and in urine from normal and recurrent stone forming volunteers. The stones were characterized by optical and spectroscopic techniques.Results:The stones were characterized to be monoclinic, prismatic and bipyramidal habit which is of calcium monohydrate and dihydrate nature. The FTIR displayed fingerprint corresponding to calcium oxalate in the control while in NaSH treated, S=O vibrations were visible in the spectrum. The order of percentage inhibition was NaSH>Na2S2O3>Na2SO4.Conclusion:Our study indicates that sodium hydrogen sulfide and its metabolite thiosulfate are inhibitors of calcium oxalate stone agglomeration which makes them unstable both in physiological buffer and in urine. This effect is attributed to pH changes and complexing of calcium by S2O32-and SO42- moiety produced by the test compounds.

Erosion protection by calcium lactate/sodium fluoride rinses under different salivary flows in vitro.

Science.gov (United States)

Borges, Alessandra B; Scaramucci, Taís; Lippert, Frank; Zero, Domenick T; Hara, Anderson T

2014-01-01

This study investigated the effect of a calcium lactate prerinse on sodium fluoride protection in an in vitro erosion-remineralization model simulating two different salivary flow rates. Enamel and dentin specimens were randomly assigned to 6 groups (n = 8), according to the combination between rinse treatments - deionized water (DIW), 12 mM NaF (NaF) or 150 mM calcium lactate followed by NaF (CaL + NaF) - and unstimulated salivary flow rates - 0.5 or 0.05 ml/min - simulating normal and low salivary flow rates, respectively. The specimens were placed into custom-made devices, creating a sealed chamber on the specimen surface connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min, followed by artificial saliva (0.5 or 0.05 ml/min) for 60 min. This cycle was repeated 4×/day for 3 days. Rinse treatments were performed daily 30 min after the 1st and 4th erosive challenges, for 1 min each time. Surface loss was determined by optical profilometry. KOH-soluble fluoride and structurally bound fluoride were determined in specimens at the end of the experiment. Data were analyzed by 2-way ANOVA and Tukey tests (α = 0.05). NaF and CaL + NaF exhibited significantly lower enamel and dentin loss than DIW, with no difference between them for normal flow conditions. The low salivary flow rate increased enamel and dentin loss, except for CaL + NaF, which presented overall higher KOH-soluble and structurally bound fluoride levels. The results suggest that the NaF rinse was able to reduce erosion progression. Although the CaL prerinse considerably increased F availability, it enhanced NaF protection against dentin erosion only under hyposalivatory conditions.

Characterization of the calcium-fluoroaluminosilicate glass prepared by a non-hydrolytic sol-gel route for future dental application as glass ionomer cement

Directory of Open Access Journals (Sweden)

Alexandre Cestari

2009-06-01

Full Text Available Glass ionomer cements are widely employed in dentistry due to their physical, biological and mainly anti-caries properties. Glass ionomers consist of an aluminosilicate glass matrix modified with other elements, and they contain large quantities of fluorine. In this study, we report on the preparation of calcium-fluoroaluminosilicate glasses by a nonhydrolytic sol-gel route as an alternative approach to obtaining alumina-silica matrices. The glass powders were prepared via the non-hydrolytic sol-gel method, by mixing AlCl3, SiCl4, CaF2, AlF3, NaF, and AlPO4. The powders were studied by thermal analysis (TG/DTA/DSC, photoluminescence (PL, nuclear magnetic resonance (NMR27Al-29Si, and X ray diffraction (XRD. TG/DTA/DSC analyses revealed a constant mass loss due to structural changes during the heating process, which was confirmed by NMR and PL. A stable aluminosilicate matrix with potential future application as a glass ionomer base was obtained.

Crystal structure of metagenomic β-xylosidase/ α-l-arabinofuranosidase activated by calcium.

Science.gov (United States)

Matsuzawa, Tomohiko; Kaneko, Satoshi; Kishine, Naomi; Fujimoto, Zui; Yaoi, Katsuro

2017-09-01

The crystal structure of metagenomic β-xylosidase/α-l-arabinofuranosidase CoXyl43, activated by calcium ions, was determined in its apo and complexed forms with xylotriose or l-arabinose in the presence and absence of calcium. The presence of calcium ions dramatically increases the kcat of CoXyl43 for p-nitrophenyl β-d-xylopyranoside and reduces the Michaelis constant for p-nitrophenyl α-l-arabinofuranoside. CoXyl43 consists of a single catalytic domain comprised of a five-bladed β-propeller. In the presence of calcium, a single calcium ion was observed at the centre of this catalytic domain, behind the catalytic pocket. In the absence of calcium, the calcium ion was replaced with one sodium ion and one water molecule, and the positions of these cations were shifted by 1.3 Å. The histidine-319 side chain, which coordinates to the 2-hydroxyl oxygen atom of the bound xylose molecule in the catalytic pocket, also coordinates to the calcium ion, but not to the sodium ion. The calcium-dependent increase in activity appears to be caused by the structural change in the catalytic pocket induced by the tightly bound calcium ion and coordinating water molecules, and by the protonation state of glutamic acid-268, the catalytic acid of the enzyme. Our findings further elucidate the complex relationship between metal ions and glycosidases. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

High-power microcavity lasers based on highly erbium-doped sol-gel aluminosilicate glasses

International Nuclear Information System (INIS)

Le Ngoc Chung; Chu Thi Thu Ha; Nguyen Thu Trang; Pham Thu Nga; Pham Van Hoi; Bui Van Thien

2006-01-01

High-power whispering-gallery-mode (WGM) lasing from highly erbium-doped sol-gel aluminosilicate microsphere cavity coupled to a half-tapered optical fiber is presented. The lasing output power as high as 0.45 mW (-3.5 dBm) was obtained from sol-gel glass microsphere cavity with diameters in the range of 40-150 μm. The sol-gel method for making highly concentration Er-doped aluminosilicate glasses with Er-ion concentrations from 0.125 to 0.65 mol% of Er 3+ is described. Controlling collected lasing wavelength at each WGM is possible by adjusting the distance between the half-taper fiber and the microcavity and by diameter of the waist of half-taper fiber. Using the analytic formulas we calculated the TE and TM lasing modes and it is shown that the experimental results are in good agreement with the calculation prediction

The influence of calcium lignosulphonate - sodium bicarbonate on the status of ettringite crystallization in fly ash cement paste

Energy Technology Data Exchange (ETDEWEB)

Yang, K.; Zhang, C.; Liu, Z. [Hebei Institute of Technology, Tang Shan (China)

2002-01-01

Calcium lignosulphonate (CL) - sodium bicarbonate (SB) (a total of 0.7% by weight of cement and CL to SB ratio of 1:1.8) will cause the fluidity of fly ash cement paste to decrease rapidly. It is the variation of the status of ettringite crystallization that causes this phenomenon. Experimental results show that CL-SB affects the liquid-phase composition of fly ash cement paste remarkably. As a result, ettringite crystallizes out in the shape of needles from the solution. These needle-like crystal particles are distributed in the solution at a certain distance from the surface of clinker particles. At the initial hydration stage, the crystallization of ettringite is stronger in fly ash cement with calcined gypsum than in fly ash cement with gypsum. 5 refs., 10 figs., 2 tabs.

Ouabain enhancement of compound 48/80 induced histamine secretion from rat peritoneal mast cells: dependence on extracellular sodium

DEFF Research Database (Denmark)

Knudsen, T; Bertelsen, Niels Haldor; Johansen, Torben

1992-01-01

Purified populations of rat peritoneal mast cells were used to study the effect of ouabain on compound 48/80-induced histamine secretion and on 86Rb+ uptake. 86Rb+ was used as a tracer for extracellular K+. The calculated value of the ouabain-sensitive uptake of K+ and 86Rb+ was considered...... on the secretion occurs in the presence of sodium but not when sodium was replaced by lithium. Preservation by ouabain of a high intracellular sodium content in sodium-loaded cells was associated with preservation of the secretory response in a calcium-free medium. In the presence of lanthanum in a calcium...

Energetics of sodium-calcium exchanged zeolite A.

Science.gov (United States)

Sun, H; Wu, D; Guo, X; Shen, B; Navrotsky, A

2015-05-07

A series of calcium-exchanged zeolite A samples with different degrees of exchange were prepared. They were characterized by powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). High temperature oxide melt drop solution calorimetry measured the formation enthalpies of hydrated zeolites CaNa-A from constituent oxides. The water content is a linear function of the degree of exchange, ranging from 20.54% for Na-A to 23.77% for 97.9% CaNa-A. The enthalpies of formation (from oxides) at 25 °C are -74.50 ± 1.21 kJ mol(-1) TO2 for hydrated zeolite Na-A and -30.79 ± 1.64 kJ mol(-1) TO2 for hydrated zeolite 97.9% CaNa-A. Dehydration enthalpies obtained from differential scanning calorimetry are 32.0 kJ mol(-1) H2O for hydrated zeolite Na-A and 20.5 kJ mol(-1) H2O for hydrated zeolite 97.9% CaNa-A. Enthalpies of formation of Ca-exchanged zeolites A are less exothermic than for zeolite Na-A. A linear relationship between the formation enthalpy and the extent of calcium substitution was observed. The energetic effect of Ca-exchange on zeolite A is discussed with an emphasis on the complex interactions between the zeolite framework, cations, and water.

The effects of calcium and sodium bicarbonate on severe hyperkalaemia during cardiopulmonary resuscitation: A retrospective cohort study of adult in-hospital cardiac arrest.

Science.gov (United States)

Wang, Chih-Hung; Huang, Chien-Hua; Chang, Wei-Tien; Tsai, Min-Shan; Yu, Ping-Hsun; Wu, Yen-Wen; Hung, Kuan-Yu; Chen, Wen-Jone

2016-01-01

Calcium and sodium bicarbonate (SB) are frequently used in treating patients with severe hyperkalaemia. We evaluated the efficacy of these medications for the treatment of severe hyperkalaemia during cardiopulmonary resuscitation (CPR). We also hypothesised that the effects of these medications might be associated with serum potassium level during CPR. We conducted a retrospective observational study in a single medical centre. From adult patients who had suffered an in-hospital cardiac arrest from 2006 through 2012, we included those with a serum potassium level>6.5 mEq/L measured during CPR. We used multivariable logistic regression analysis to study the association of calcium/SB with sustained return of spontaneous circulation (ROSC). Among the 109 patients included in our analysis, 40 (36.7%) patients achieved sustained ROSC, and only four (3.7%) patients survived to hospital discharge. The mean serum potassium level was 7.8 mEq/L. The analysis indicated that administration of SB was positively associated with sustained ROSC when serum potassium level was <7.9 mEq/L (odds ratio [OR]: 10.51; 95% confidence interval [CI]: 1.50-112.89; p: 0.03); administration of calcium and SB was also positively associated with sustained ROSC when serum potassium level was <9.4 mEq/L (OR: 51.11; 95% CI: 3.12-1639.16; p: 0.01). The use of calcium and SB might be effective in the treatment of severe hyperkalaemia during cardiac arrest. The efficacy of SB/calcium correlated with serum potassium level. However, because the number of patients included in the analysis was small, this conclusion should be further examined in the future. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Preparation and characterization of cesium-137 aluminosilicate pellets for radioactive source applications

International Nuclear Information System (INIS)

Schultz, F.J.; Tompkins, J.A.; Haff, K.W.; Case, F.N.

1981-07-01

Twenty-seven fully loaded 137 Cs aluminosilicate pellets were fabricated in a hot cell by the vacuum hot pressing of a cesium carbonate/montmorillonite clay mixture at 1500 0 C and 570 psig. Four pellets were selected for characterization studies which included calorimetric measurements, metallography, scanning electron microscope and electron backscattering (SEM-BSE), electron microprobe, x-ray diffraction, and cesium ion leachability measurements. Each test pellet contained 437 to 450 curies of 137 Cs as determined by calorimetric measurements. Metallographic examinations revealed a two-phase system: a primary, granular, gray matrix phase containing large and small pores and small pore agglomerations, and a secondary fused phase interspersed throughout the gray matrix. SEM-BSE analyses showed that cesium and silicon were uniformly distributed throughout both phases of the pellet. This indicated that the cesium-silicon-clay reaction went to completion. Aluminum homogeneity was unconfirmed due to the high background noise associated with the inherent radioactivity of the test specimens. X-ray diffraction analyses of both radioactive and non-radioactive aluminosilicate pellets confirmed the crystal lattice structure to be pollucite. Cesium ion quasistatic leachability measurements determined the leach rates of fully loaded 137 Cs sectioned pollucite pellets to date to be 4.61 to 34.4 x 10 -10 kg m -2 s -1 , while static leach tests performed on unsectioned fully loaded pellets showed the leach rates of the cesium ion to date to be 2.25 to 3.41 x 10 -12 kg m -2 s -1 . The cesium ion diffusion coefficients through the pollucite pellet were calculated using Fick's first and second laws of diffusion. The diffusion coefficients calculated for three tracer level 137 Cs aluminosilicate pellets were 1.29 x 10 -16 m 2 s -1 , 6.88 x 10 -17 m 2 s -1 , and 1.35 x 10 -17 m 2 s -1 , respectively

Thallium and manganese complexes involved in the luminescence emission of potassium-bearing aluminosilicates

Energy Technology Data Exchange (ETDEWEB)

Gomez-Gonzalez, Miguel A., E-mail: miguel.gomez@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Garcia-Guinea, Javier, E-mail: guinea@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Garrido, Fernando, E-mail: fernando.garrido@mncn.csic.es [Museo Nacional de Ciencias Naturales, CSIC, Jose Gutierrez Abascal 2, Madrid E-28006 (Spain); Townsend, Peter D., E-mail: pdtownsend@gmail.com [School of Science and Technology, University of Sussex, Brighton BN1 9QH (United Kingdom); Marco, Jose-Francisco, E-mail: jfmarco@iqfr.csic.es [Instituto de Química-Física Rocasolano, CSIC, Calle Serrano 119, Madrid E-28006 (Spain)

2015-03-15

The luminescence emission at 285 nm in natural K-feldspar has been studied by Russian groups and associated with thallium ions in structural positions of K{sup +} sites as artificially thallium-doped feldspars display the same emission band. Here attention is focussed on spectra of CL emission bands centered near 285 and 560 nm from paragenetic adularia, moscovite and quartz micro-inclusions. With accesorial thallium they show clear resemblances to each other. Associated sedimentary and hydrothermal aluminosilicate samples collected from Guadalix (Madrid, Spain) were analyzed with a wide range of experimental techniques including Environmental Scanning Electron Microscopy (ESEM) with an attached X-Ray Energy-Dispersive Spectrometer (EDS) and a cathodoluminescence probe (CL) and Electron Probe Microanalysis (EPMA), X-Ray Fluorescence Spectrometry (XRF), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), Differential and Thermogravimetric Analyses (DTA-TG), radioluminescence (RL), Mössbauer spectroscopy and X-Ray Photoelectron Spectrometry (XPS). The luminescence emission bands at 285 and 560 nm seem to be associated with hydrous thallium–manganese complexes bonded to potassium-bearing aluminosilicates since various minerals such as K-feldspar, moscovite and quartz micro-inclusions display similar CL spectra, accesorial thallium and hydroxyl groups. The presence of iron introduces a brown color which is attributed to submicroscopic iron oxides detectable in the optical and chemical microanalysis, but this does not contribute to the luminescence emission. The XPS Mn 2p spectrum of the adularia sample at room temperature is composed of a spin–orbit doublet plus clear shake-up satellite structure ∼4 eV above the main photoemision lines and is consistent with Mn{sup 2+} in good agreement with the observed luminescence emission at 560 nm for aluminosilicates produced by a {sup 4}T1({sup 4}G)→{sup 6}A1({sup 6}S) transition in tetrahedrally

The leaching of trifloxysulfuron-sodium and pyrithiobac-sodium in soil columns as a function of soil liming - doi: 10.4025/actasciagron.v35i2.16349

Directory of Open Access Journals (Sweden)

Naiara Guerra

2012-12-01

Full Text Available Scarce research has been published concerning the effect of soil pH on the leaching potential of herbicides in tropical soils. Thus, we designed this study to evaluate the influence of soil liming on the leaching of trifloxysulfuron-sodium and pyrithiobac-sodium after simulated rainfall depths in soil columns. In the study, two trials were conducted simultaneously; the first experiment evaluated trifloxysulfuron-sodium (7.5 g ha-1, while the second experiment evaluated pyrithiobac-sodium (70 g ha-1. Both experiments were conducted in a randomized block design with a 2 x 4 x 5 factorial scheme and four replications. The design’s factors corresponded to 2 soil liming conditions (with or without liming, 4 simulated rainfall depths (0, 15, 30, and 45 mm and 5 depths in the soil column (0-5, 5-10, 10-15, 15-20, and 20-25 cm. The trials were repeated, and only the source for the soil neutralization was changed, i.e., dolomitic limestone in Experiment 1 and calcium oxide in Experiment 2. Compared to trifloxysulfuron-sodium, the herbicide pyrithiobac-sodium indicated a greater potential for leaching. With more acidic soils, the leaching potential in limed soils was greater for both herbicides. Only the liming that used calcium oxide provided a significant leaching of trifloxysulfuron-sodium for depths greater than 20 cm. Simulated rainfall ≥ 15 mm provided leaching of pyrithiobac-sodium to a depth of 25 cm at near-neutral soil pH values.

Negative thermal expansion of lithium aluminosilicate ceramics at cryogenic temperatures

International Nuclear Information System (INIS)

Garcia-Moreno, Olga; Fernandez, Adolfo; Khainakov, Sergei; Torrecillas, Ramon

2010-01-01

Five lithium aluminosilicate compositions of the LAS system have been synthesized and sintered. The coefficient of thermal expansion of the sintered samples has been studied down to cryogenic conditions. The data presented here under cryogenic conditions will be of value in the future design of new composite materials with very low thermal expansion values. The variation in thermal expansion properties with composition and sintering temperature was studied and is discussed in relation to composition and crystal structure.

Phase 2 THOR Steam Reforming Tests for Sodium Bearing Waste Treatment

Energy Technology Data Exchange (ETDEWEB)

Nicholas R. Soelberg

2004-01-01

About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste is stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Steam reforming is a candidate technology being investigated for converting the waste into a road ready waste form that can be shipped to the Waste Isolation Pilot Plant in New Mexico for interment. A steam reforming technology patented by Studsvik, Inc., and licensed to THOR Treatment Technologies has been tested in two phases using a Department of Energy-owned fluidized bed test system located at the Science Applications International Corporation (SAIC) Science and Technology Applications Research Center located in Idaho Falls, Idaho. The Phase 1 tests were reported earlier in 2003. The Phase 2 tests are reported here. For Phase 2, the process feed rate, stoichiometry, and chemistry were varied to identify and demonstrate process operation and product characteristics under different operating conditions. Two test series were performed. During the first series, the process chemistry was designed to produce a sodium carbonate product. The second series was designed to produce a more leach-resistant, mineralized sodium aluminosilicate product. The tests also demonstrated the performance of a MACT-compliant off-gas system.

Synthesis and behavior at heating of amorphous calcium diphosphate

International Nuclear Information System (INIS)

Levchenko, L.V.; Nurkina, Z.S.; Griggs, D.; Sinyayev, V.A.

2005-01-01

There is description of synthesis of amorphous calcium diphosphate in the article. The compound was received via exchange reaction between sodium diphosphate and calcium chloride in water solution. The results of investigation of behavior when heated of produced substance are presented here as well. Composition and structure of precipitated substances and products of its thermal convention were determined by methods of IR-, NMR 31 P and X-ray spectroscopy

Comparative evaluation of the remineralizing efficacy of calcium sodium phosphosilicate agent and fluoride based on quantitative and qualitative analysis

Directory of Open Access Journals (Sweden)

Saranya Mony

2015-01-01

Full Text Available Background: Calcium sodium phosphosilicate (NovaMin is an agent that is claimed to release calcium and phosphate ions intraorally to help the self-repair process of enamel. It is used extensively as a desensitizing agent, but the chemical reactions that occur may promote apatite formation enhancing remineralization. The present study was undertaken to evaluate the ability of NovaMin to remineralize an experimentally induced demineralized lesion. The evaluation was done based on the quantitative and qualitative analysis of enamel over the period of 15 and 30 days. Materials and Methods: A sample of 120 noncarious premolar teeth extracted for orthodontic reasons were used for the study. Baseline data for hardness, Ca/PO 4 , and surface characteristics before and after demineralization process was obtained. All the teeth were brushed twice daily at 12 h interval with the test agents using a powered toothbrush for 2 min. The samples were tested on the 15 th and 30 th day. Results: Calcium phosphate ratio and hardness in both the groups improved during the study period. Fluoride group showed higher values for Ca/PO 4 and hardness but was not statistically significant with the P > 0.05. Scanning electron microscope pictures showed that the deposition of the material over the decalcified enamel is more smoother and uniform with NovaMin and more irregular with fluoride. Relevance: NovaMin is found to be as effective in improving the Ca/PO 4 ratio and hardness in a demineralized enamel as fluoride. Hence, it can be a new alternate material for remineralization of enamel with less toxic effects compared to fluorides.

Calculation of the 13C NMR shieldings of the C0 2 complexes of aluminosilicates

Science.gov (United States)

Tossell, J. A.

1995-04-01

13C NMR shieldings have been calculated using the random-phase-approximation, localized-orbital local-origins version of ab initio coupled Hartree-Fuck perturbation theory for CO 2 and and for several complexes formed by the reaction of CO 2 with molecular models for aluminosilicate glasses, H 3TOT'H3 3-n, T,T' = Si,Al. Two isomeric forms of the CO 2-aluminosilicate complexes have been considered: (1) "CO 2-like" complexes, in which the CO 2 group is bound through carbon to a bridging oxygen and (2) "CO 3-like" complexes, in which two oxygens of a central CO 3 group form bridging bonds to the two TH 3 groups. The CO 2-like isomer of CO 2-H 3SiOSiH 3 is quite weakly bonded and its 13C isotropic NMR shielding is almost identical to that in free CO 2. As Si is progressively replaced by Al in the - H terminated aluminosilicate model, the CO 2-like isomers show increasing distortion from the free CO 2 geometry and their 13C NMR shieldings decrease uniformly. The calculated 13C shielding value for H 3AlO(CO 2)AlH 3-2 is only about 6 ppm larger than that calculated for point charge stabilized CO 3-2. However, for a geometry of H 3SiO(CO 2) AlH 3-1, in which the bridging oxygen to C bond length has been artificially increased to that found in the - OH terminated cluster (OH) 3SiO(CO 2)Al(OH) 3-1, the calculated 13C shielding is almost identical to that for free CO 2. The CO 3-like isomers of the CO 2-aluminosili-cate complexes show carbonate like geometries and 13C NMR shieldings about 4-9 ppm larger than those of carbonate for all T,T' pairs. For the Si,Si tetrahedral atom pair the CO 2-like isomer is more stable energetically, while for the Si,Al and Al,Al cases the CO 3-like isomer is more stable. Addition of Na + ions to the CO 3-2 or H 3AlO(CO 2)AlH 3-2 complexes reduces the 13C NMR shieldings by about 10 ppm. Complexation with either Na + or CO 2 also reduces the 29Si NMR shieldings of the aluminosilicate models, while the changes in 27Al shielding with Na + or CO 2

The aluminosilicate fraction of North Pacific manganese nodules

Science.gov (United States)

Bischoff, J.L.; Piper, D.Z.; Leong, K.

1981-01-01

Nine nodules collected from throughout the deep North Pacific were analyzed for their mineralogy and major-element composition before and after leaching with Chester-Hughes solution. Data indicate that the mineral phillipsite accounts for the major part (> 75%) of the aluminosilicate fraction of all nodules. It is suggested that formation of phillipsite takes place on growing nodule surfaces coupled with the oxidation of absorbed manganous ion. All the nodules could be described as ternary mixtures of amorphous iron fraction (Fe-Ti-P), manganese oxide fraction (Mn-Mg Cu-Ni), and phillipsite fraction (Al-Si-K-Na), these fractions accounting for 96% of the variability of the chemical composition. ?? 1981.

In-situ high-temperature Raman spectroscopic studies of aluminosilicate liquids

Science.gov (United States)

Daniel, Isabelle; Gillet, Philippe; Poe, Brent T.; McMillan, Paul F.

1995-03-01

We have measured in-situ Raman spectra of aluminosilicate glasses and liquids with albite (NaAlSi3 O8) and anorthite (CaAl2Si2O8) compositions at high temperatures, through their glass transition range up to 1700 and 2000 K, respectively. For these experiments, we have used a wire-loop heating device coupled with micro-Raman spectroscopy, in order to achieve effective spatial filtering of the extraneous thermal radiation. A major concern in this work is the development of methodology for reliably extracting the first and second order contributions to the Raman scattering spectra of aluminosilicate glasses and liquids from the high temperature experimental data, and analyzing these in terms of vibrational (anharmonic) and configurational changes. The changes in the first order Raman spectra with temperature are subtle. The principal low frequency band remains nearly constant with increasing temperature, indicating little change in the T-O-T angle, and that the angle bending vibration is quite harmonic. This is in contrast to vitreous SiO2, studied previously. Above Tg, intensity changes in the 560 590 cm-1 regions of both sets of spectra indicate configurational changes in the supercooled liquids, associated with formation of additional Al-O-Al linkages, or 3-membered (Al, Si)-containing rings. Additional intensity at 800 cm-1 reflects also some rearrangement of the Si-O-Al network.

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

OpenAIRE

Zhang, Long; Liu, Peng

2008-01-01

AbstractThe uniform polyaniline (PANI) nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conduct...

Report on the vitrification and devitrification of Hanford, Washington soil. Final report

International Nuclear Information System (INIS)

King, J.A.; SubbaRao, S.C.

1983-01-01

This study as focused principally on the effects of melting or vitrification and recrystallization or devitrification on soil from the Hanford Reservation in Washington State. The fusion properties of soil are important because the containment of nuclear material in in-situ vitrified soil is a possible requirement. An understanding of the physical and chemical properties of the soil is important in determinaing how the soil can contain the nuclear material. The soil itself is composed of a plagioclastic feldspar, quartz, and hematite. The feldspar is made up of albite and anorthite. When the soil is heated, the first mineral to melt is the albite between 1100 0 C and 1200 0 C. The mineral anorthite melts above 1310 0 C and hematite below 1700 0 C. The quartz does not melt until the temperature exceeds 1715 0 C. The albite in the glass is sodium aluminosilicate. When the albite melts, microscopic spheres of non-crystalline, low-melting sodium silicate form. This indicates that the aluminosilicate matrix decomposes when heated. When crystals, which were previously fused, are heated: crystals begin to reform above 900 0 C. The minerals which crystallize are feldspar and magnetite, an iron oxide. Recrystallization should begin at a temperature 250 0 C below the liquidus point. The leaching of sodium, copper, calcium, and aluminum decreased with increasing fusion temperature, while the leaching of iron and barium increased with increasing fusion temperature

Synthesis, characterization and antibacterial activity of a new calcium complex using sodium 2-mercaptobenzothiazole and 1, 10-phenanthroline as ligands

Science.gov (United States)

Gulab, Hussain; Shah, Zarbad; Mahmood, Mazhar; Shah, Syed Raza; Ali, Sajid; Iqbal, Muhammad; Khan, Muhammad Naeem; Flörke, Ulrich; Khan, Shahid Ali

2018-02-01

A new Ca-complex (Ca (H2 O)4 (C12 H8 N2)2)(C7 H4 N S2)2 has been synthesized by the reaction of calcium chloride, sodium 2-mercaptobenzothiazole and 1,10-phenanthroline. The complex was characterized by using X-ray crystallography and FT-IR spectroscopy. The complex was tested against different bacterial strains i.e. Staphylococcus aureus, Escherichia coli, Acinetobacter baumanni, Providencia stuartii and Pseudomonas aeruginosa. The complex was found to exhibit remarkable anti-bacterial activity against Pseudomonas aeruginosa with an inhibition zone of 25 mm and good anti-bacterial activity against Acinetobacter baumanni with a zone of inhibition of 16 mm comparable to the Levofloxacin standard (zone of inhibition of 25 mm).

Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

NARCIS (Netherlands)

Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.

2011-01-01

The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

Structural and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from alite hydration in the presence of sodium and potassium hydroxide

International Nuclear Information System (INIS)

Mendoza, Oscar; Giraldo, Carolina; Camargo, Sergio S.; Tobón, Jorge I.

2015-01-01

This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from the hydration of pure alite. Monoclinic (MIII) alite was synthesized and hydrated, using water-to-alite ratios of 0.5 and 0.6 and additions of 10% NaOH and KOH by weight of alite. Based on results of X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, Nuclear Magnetic Resonance and nanoindentation, two different effects of the alkaline hydroxides on the hydration reaction of alite, both at early and later ages, can be identified: (i) a differentiated hydration process, attributed to an enhancement in calcium hydroxide (CH) precipitation and a stimulation of the C-S-H nuclei; and (ii) an increase in the elastic modulus of the C-S-H aggregations, attributed to an electrostatic attraction between positive charges from the alkaline cations and negative charges from the C-S-H structure

Structural and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from alite hydration in the presence of sodium and potassium hydroxide

Energy Technology Data Exchange (ETDEWEB)

Mendoza, Oscar, E-mail: oamendoz@unal.edu.co [Grupo del Cemento y Materiales de Construcción (CEMATCO). Universidad Nacional de Colombia, Facultad de Minas, Medellín (Colombia); Giraldo, Carolina [Cementos Argos S.A., Medellín (Colombia); Camargo, Sergio S. [Engenharia Metalúrgica e de Materiais, Universidade Federal do Rio de Janeiro/COPPE, Rio de Janeiro (Brazil); Tobón, Jorge I. [Grupo del Cemento y Materiales de Construcción (CEMATCO). Universidad Nacional de Colombia, Facultad de Minas, Medellín (Colombia)

2015-08-15

This research evaluates the effect of sodium and potassium hydroxide on the structure and nano-mechanical properties of Calcium Silicate Hydrate (C-S-H) formed from the hydration of pure alite. Monoclinic (MIII) alite was synthesized and hydrated, using water-to-alite ratios of 0.5 and 0.6 and additions of 10% NaOH and KOH by weight of alite. Based on results of X-ray diffraction, isothermal calorimetry, thermogravimetric analysis, Nuclear Magnetic Resonance and nanoindentation, two different effects of the alkaline hydroxides on the hydration reaction of alite, both at early and later ages, can be identified: (i) a differentiated hydration process, attributed to an enhancement in calcium hydroxide (CH) precipitation and a stimulation of the C-S-H nuclei; and (ii) an increase in the elastic modulus of the C-S-H aggregations, attributed to an electrostatic attraction between positive charges from the alkaline cations and negative charges from the C-S-H structure.

A short introduction to the new principle of binding ration calcium with sodium zeolite

DEFF Research Database (Denmark)

Jørgensen, R J; Bjerrum, M J; Classen, H

2003-01-01

This paper summarise the development of the new principle of preventing parturient hypocalcaemia by reducing the bioavailability of ration calcium with calcium binders, based on the idea that a negative calcium balance would stimulate natural defence mechanisms against threatening hypocalcaemia...

On the structure of amorphous calcium carbonate--a detailed study by solid-state NMR spectroscopy.

Science.gov (United States)

Nebel, Holger; Neumann, Markus; Mayer, Christian; Epple, Matthias

2008-09-01

The calcium carbonate phases calcite, aragonite, vaterite, monohydrocalcite (calcium carbonate monohydrate), and ikaite (calcium carbonate hexahydrate) were studied by solid-state NMR spectroscopy ( (1)H and (13)C). Further model compounds were sodium hydrogencarbonate, potassium hydrogencarbonate, and calcium hydroxide. With the help of these data, the structure of synthetically prepared additive-free amorphous calcium carbonate (ACC) was analyzed. ACC contains molecular water (as H 2O), a small amount of mobile hydroxide, and no hydrogencarbonate. This supports the concept of ACC as a transient precursor in the formation of calcium carbonate biominerals.

Charge-transfer state excitation as the main mechanism of the photodarkening process in ytterbium-doped aluminosilicate fibres

Energy Technology Data Exchange (ETDEWEB)

Bobkov, K K; Rybaltovsky, A A; Vel' miskin, V V; Likhachev, M E; Bubnov, M M; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Umnikov, A A; Gur' yanov, A N; Vechkanov, N N [G.G.Devyatykh Institute of Chemistry of High-Purity Substances, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation); Shestakova, I A [Open Joint-Stock Company M.F. Stel' makh Polyus Research Institute, Moscow (Russian Federation)

2014-12-31

We have studied photodarkening in ytterbium-doped fibre preforms with an aluminosilicate glass core. Analysis of their absorption and luminescence spectra indicates the formation of stable Yb{sup 2+} ions in the glass network under IR laser pumping at a wavelength λ = 915 nm and under UV irradiation with an excimer laser (λ = 193 nm). We have performed comparative studies of the luminescence spectra of the preforms and crystals under excitation at a wavelength of 193 nm. The mechanism behind the formation of Yb{sup 2+} ions and aluminium – oxygen hole centres (Al-OHCs), common to ytterbium-doped YAG crystals and aluminosilicate glass, has been identified: photoinduced Yb{sup 3+} charge-transfer state excitation. (optical fibres)

Kinetic study of human hand sodium using local in vivo neutron activation analysis

International Nuclear Information System (INIS)

Cohen Boulakia, Francine.

1978-01-01

Using local 'in vivo' activation analysis, turnover of human hand sodium is studied in 14 subjects, 7 controls and 7 decalcified osteoporotics patients. The hand of each subject is irradiated with neutrons emitted by 52 Cf sources; the equivalent dose delivered is 8 cGy. The 24 Na activity variation is plotted as function of time and the experimental curve so obtained is fitted to two exponentials. Two compartements are identified: a rapidly exchangeable one, with a half life of 1 h; an other, with a very slow turnover, the half lifes varying from 79 h to 35 h as the calcium concentration becomes sub-normal. The ratios calcium to slowly exchangeable sodium and rapidly to slowly exchangeable sodium appear to be promising for the evaluation of bone disease [fr

Preliminary formulation studies for a ''hydroceramic'' alternative waste form for INEEL HLW

International Nuclear Information System (INIS)

Siemer, D.D.; Gougar, M.L.D.; Grutzeck, M.W.; Scheetz, B.E.

1999-01-01

Herein the authors discuss scoping studies performed to develop an efficient way to prepare the Idaho National Engineering and Environmental Laboratory (INEEL) nominally high-level (∼40 W/m 3 ) calcined radioactive waste (HLW) and liquid metal (sodium) reactor coolants for disposal. The investigated approach implements the chemistry of Hanford's cancrinite-making clay reaction process via Oak Ridge National Laboratory's (ORNL's) formed-under-elevated-temperatures-and-pressures concrete monolith-making technology to make hydroceramics (HCs). The HCs differ from conventional Portland cement/blast furnace slag (PC/BFS) grouts in that the binder minerals formed during the curing process are hydrated alkali-aluminosilicates (feldspathoids-sodalites, cancrinites, and zeolites) rather than hydrated calcium silicates (CSH). This is desirable because (a) US defense-type radioactive wastes generally contain much more sodium and aluminum than calcium; (b) sodalites/cancrinites do a much better job of retaining the anionic components of real radioactive waste (e.g., nitrate) than do calcium silicates; (c) natural feldspathoids form from glasses (and therefore are more stable) in that region of the United States where a repository for this sort of waste could be sited; and (d) if eventually deemed necessary, feldspathoid-type concrete wasteforms could be hot-isostatically-pressed into even more durable materials without removing them from their original canisters

Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

Energy Technology Data Exchange (ETDEWEB)

Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

2007-08-16

Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

Valorization of Calcium Carbonate-Based Solid Wastes for the Treatment of Hydrogen Sulfide from the Gas Phase

OpenAIRE

Pham Xuan , Huynh; Pham Minh , Doan; Galera Martinez , Marta; Nzihou , Ange; Sharrock , Patrick

2015-01-01

International audience; This paper focuses on the valorization of calcium carbonate-based solid wastes for theremoval of hydrogen sulfide from gas phase. Two solid wastes taken from industrial sites for theproduction of sodium carbonate and sodium bicarbonate by the Solvay process® were analyzedby different physico-chemical methods. Calcium carbonate was found as the main component ofboth the solid wastes. Trace amounts of other elements such as Mg, Al, Fe, Si, Cl, Na etc. werealso present in...

Comparison of sodium, potassium, calcium, magnesium, zinc, copper and iron concentrations of elements in 24-h urine and spot urine in hypertensive patients with healthy renal function.

Science.gov (United States)

Zhang, Tianjing; Chang, Xiaoyu; Liu, Wanlu; Li, Xiaoxia; Wang, Faxuan; Huang, Liping; Liao, Sha; Liu, Xiuying; Zhang, Yuhong; Zhao, Yi

2017-12-01

Sodium, potassium, calcium, magnesium, zinc, copper and iron are associated with the sequela of hypertension. The most reliable method for testing those elements is by collecting 24-h urine samples. However, this is cumbersome and collection of spot urine is more convenient in some circumstance. The aim of this study was to compare the concentrations of different elements in 24-h urine and spot urine. Data was collected from a sub-study of China Salt Substitute and Stroke Study. 240 participants were recruited randomly from 12 villages in two counties in Ningxia, China. Both spot and 24-h urine specimens were collected from each patient. Routine urine test was conducted, and concentration of elements was measured using microwave digestion and Inductively Coupled Plasma-Optical Emission Spectrometry. Partial correlation analysis and Spearman correlation analysis were used to investigate the concentration of different elements and the relationship between 24- h urine and spot urine. A partial correlation in sodium, potassium, calcium, magnesium and iron was found between paired 24-h urine and spot urine samples except copper and zinc: 0.430, 0.426, 0.550, 0.221 and 0.191 respectively. Spot urine can replace 24-h urine for estimating some of the elements in hypertensive patients with normal renal function. Copyright © 2017 Elsevier GmbH. All rights reserved.

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.

Science.gov (United States)

Elmore, Amy R

2005-01-01

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 (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

Fast calcium transients translate the distribution and conduction of neural activity in different regions of a single sensory neuron.

Science.gov (United States)

Purali, Nuhan

2017-09-01

In the present study, cytosolic calcium concentration changes were recorded in response to various forms of excitations, using the fluorescent calcium indicator dye OG-BAPTA1 together with the current or voltage clamp methods in stretch receptor neurons of crayfish. A single action potential evoked a rise in the resting calcium level in the axon and axonal hillock, whereas an impulse train or a large saturating current injection would be required to evoke an equivalent response in the dendrite region. Under voltage clamp conditions, amplitude differences between axon and dendrite responses vanished completely. The fast activation time and the modulation of the response by extracellular calcium concentration changes indicated that the evoked calcium transients might be mediated by calcium entry into the cytosol through a voltage-gated calcium channel. The decay of the responses was slow and sensitive to extracellular sodium and calcium concentrations as well as exposure to 1-10 mM NiCl 2 and 10-500 µM lanthanum. Thus, a sodium calcium exchanger and a calcium ATPase might be responsible for calcium extrusion from the cytosol. Present results indicate that the calcium indicator OG-BAPTA1 might be an efficient but indirect way of monitoring regional membrane potential differences in a single neuron.

Structure of aluminosilicate melts produced from granite rocks for the manufacturing of petrurgical glass-ceramics construction materials

Directory of Open Access Journals (Sweden)

Simakin, A. G.

2001-12-01

Full Text Available The aluminosilicate melt is a partly ordered phase and is the origin of glass for producing glassceramics and petrurgical materials. They are well extended used as construction materials for pavings and coatings. Its structure can be described in the terms of the aluminosilica tetrahedras coordination so-called Q speciation. The proportions of tetrahedra with different degree of connectivity with others (from totally connected to free has been studied by NMR and IR methods for sodium-silicate melts. Medium range structure can be characterized by the sizes of irreducible rings composed of the aluminosilica tetrahedra. Systematic increase of the four member rings proportion in the sequence of the Ab-An glasses were observed. The water dissolution in sodium-silicate glass affects the Q speciation. Cations network-modifiers positions in the melt structure are important to know since these cations stabilize particular structure configurations. Modification of the distribution of Na coordination in the sodium-silicate glass at water dissolution was determined by NMR spectroscopy. The observed modification of the hydrous aluminosilicate melt structure resulted in the shift of the eutectic composition in the granite system with decreasing of the crystallization field of feldspars. The feldspar growth rates show practically no dependence on the water content in the concentration range 2-4 wt.%. Likewise, the solved water has a little influence on the crystal growth rate of the lithium silicate phase in lithium containing glasses in accordance with estimated enhancing of the diffusion transport.

Los fundidos de alumino-silicato son una fase parcialmente ordenada. Su estructura puede ser descrita en términos de la coordinación de tetraedros de alúmina-sílice también denominados especies Q. La proporción de tetraedros con diferente grado de conectividad entre si se ha investigado por espectroscopias de RMN e IR en fundidos de silicatos

Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

International Nuclear Information System (INIS)

Wurth, R.; Pascual, M.J.; Mather, G.C.; Pablos-Martín, A.; Muñoz, F.; Durán, A.; Cuello, G.J.; Rüssel, C.

2012-01-01

A base glass of composition 3.5 Li 2 O∙0.15 Na 2 O∙0.2 K 2 O∙1.15 MgO∙0.8 BaO∙1.5 ZnO∙20 Al 2 O 3 ∙67.2 SiO 2 ∙2.6 TiO 2 ∙1.7 ZrO 2 ∙1.2 As 2 O 3 (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi 2 O 6 with nanoscaled crystals forms at 750 °C. Quantitative Rietveld refinement of samples annealed at 750 °C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, β-eucryptite-like structure (2 × 2 × 2 cell) with Li ordered in the structural channels. The Avrami parameter (n ∼ 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 ± 20 kJ mol −1 . - Highlights: ► Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. ► Combined X-ray and neutron diffraction structural refinement. ► β-Eucryptite-like structure (2 × 2×2 cell) with Li ordered in the structural channels. ► 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. ► Usage and validation of an alternative approach to calculate the Avrami parameter.

Effect of calcium hydroxide on slip casting behaviour

OpenAIRE

Şakar‐Deliormanlı, Aylin; Yayla, Zeliha

2004-01-01

The effect of calcium hydroxide addition on the casting performance of ceramic slips for sanitary ware was studied. Powder composed of feldspar (24 wt.%), quartz (24 wt.%), kaolin (35 wt.%) and ball clay (17 wt.%) was mixed with water to contain 65 wt.% of solids (specific density 1800 g/l). Either Ca(OH)2 or Na2CO3 was added at concentrations ranging between 0.060 and 0.085 wt.% and the slurries were dispersed by the optimum addition of sodium silicate. Calcium hydroxide in presence of sodiu...

Interaction of H2S with Calcium Permeable Channels and Transporters

Directory of Open Access Journals (Sweden)

Weihua Zhang

2015-01-01

Full Text Available A growing amount of evidence has suggested that hydrogen sulfide (H2S, as a gasotransmitter, is involved in intensive physiological and pathological processes. More and more research groups have found that H2S mediates diverse cellular biological functions related to regulating intracellular calcium concentration. These groups have demonstrated the reciprocal interaction between H2S and calcium ion channels and transporters, such as L-type calcium channels (LTCC, T-type calcium channels (TTCC, sodium/calcium exchangers (NCX, transient receptor potential (TRP channels, β-adrenergic receptors, and N-methyl-D-aspartate receptors (NMDAR in different cells. However, the understanding of the molecular targets and mechanisms is incomplete. Recently, some research groups demonstrated that H2S modulates the activity of calcium ion channels through protein S-sulfhydration and polysulfide reactions. In this review, we elucidate that H2S controls intracellular calcium homeostasis and the underlying mechanisms.

H-D exchange on natural aluminosilicates of orthosilicate group

International Nuclear Information System (INIS)

Markevich, S.V.; Kolesnikov, I.M.

1982-01-01

Experimental data are presented on the effect of aluminium ion coordination in the composition of polyhedrons on the capability of polyhedrons to change the reaction rate of H-D exchange (on the example of ethylene). It is shown that at temperature lower 400 deg C the rate of isotopic exchange reaction is low. Experimental results both for irradiated and non-irradiated minerals are presented. The conclusion is made that the increase of aluminosilicates activity under radiation is connected with the presence of (AlO 4 )-tetrahedrons in the system and change of their state. (AlO 5 ) and (AlO 6 )-polyhedrons are not activated with gamma rays

Adsorption of β-galactosidase on silica and aluminosilicate adsorbents

Science.gov (United States)

Atyaksheva, L. F.; Dobryakova, I. V.; Pilipenko, O. S.

2015-03-01

It is shown that adsorption of β-galactosidase of Aspergillus oryzae fungi on mesoporous and biporous silica and aluminosilicate adsorbents and the rate of the process grow along with the diameter of the pores of the adsorbent. It is found that the shape of the adsorption isotherms changes as well, depending on the texture of the adsorbent: the Michaelis constant rises from 0.3 mM for the enzyme in solution to 0.4-0.5 mM for the enzyme on a surface in the hydrolysis of o-nitrophenyl-β-D-galactopyranoside. It is concluded that β-galactosidase displays its maximum activity on the surface of biporous adsorbents.

Single-particle characterization of urban aerosol particles collected in three Korean cites using low-Z electron probe X-ray microanalysis.

Science.gov (United States)

Ro, Chul-Un; Kim, HyeKyeong; Oh, Keun-Young; Yea, Sun Kyung; Lee, Chong Bum; Jang, Meongdo; Van Grieken, René

2002-11-15

A recently developed single-particle analytical technique, called low-Z electron probe X-ray microanalysis (low-Z EPMA), was applied to characterize urban aerosol particles collected in three cities of Korea (Seoul, CheongJu, and ChunCheon) on single days in the winter of 1999. In this study, it is clearly demonstrated that the low-Z EPMA technique can provide detailed and quantitative information on the chemical composition of particles in the urban atmosphere. The collected aerosol particles were analyzed and classified on the basis of their chemical species. Various types of particles were identified, such as soil-derived, carbonaceous, marine-originated, and anthropogenic particles. In the sample collected in Seoul, carbonaceous, aluminosilicates, silicon dioxide, and calcium carbonate aerosol particles were abundantly encountered. In the CheongJu and ChunCheon samples, carbonaceous, aluminosilicates, reacted sea salts, and ammonium sulfate aerosol particles were often seen. However, in the CheongJu sample, ammonium sulfate particles were the most abundant in the fine fraction. Also, calcium sulfate and nitrate particles were significantly observed. In the ChunCheon sample, organic particles were the most abundant in the fine fraction. Also, sodium nitrate particles were seen at high levels. The ChunCheon sample seemed to be strongly influenced by sea-salt aerosols originating from the Yellow Sea, which is located about 115 km away from the city.

Trace element studies in urolithiasis; preliminary investigation on mixed calcium oxalate-struvite urinary calculi

International Nuclear Information System (INIS)

Syed, A.M.; Qadiruddin, M.; Shirin, K.; Manser, W.W.T.

1999-01-01

In this study the levels of the trace elements copper , zinc, lead, iron, aluminum, nickel, chromium along with magnesium, sodium and potassium were estimated in fifteen mixed calcium oxalate-struvite (CaOx/STR) urinary stones. The mean values of the combined results were, copper 4.24, zinc 1302, zinc 1302.10, lead 23.25, iron 36.83,nickel 0.69, chromium 1.93, magnesium 4530441, sodium 54.13 and potassium 5.93 ng mg/sup -1/. It was observed that zinc, aluminum and potassium levels were higher than in calcium oxalate(CaOx) calculi 0.05>P>0.02 and potassium levels were higher than in mixed calcium oxalate-hydroxy appetite (CaOx/APA) calculi, P<0.01. A combination of all the results was also compared with similar data from South Africa, Turkey, Austria, India, U.S.A and Japan. (author)

Calcium Homeostasis Modulator 1-Like Currents in Rat Fungiform Taste Cells Expressing Amiloride-Sensitive Sodium Currents.

Science.gov (United States)

Bigiani, Albertino

2017-05-01

Salt reception by taste cells is still the less understood transduction process occurring in taste buds, the peripheral sensory organs for the detection of food chemicals. Although there is evidence suggesting that the epithelial sodium channel (ENaC) works as sodium receptor, yet it is not clear how salt-detecting cells signal the relevant information to nerve endings. Taste cells responding to sweet, bitter, and umami substances release ATP as neurotransmitter through a nonvesicular mechanism. Three different channel proteins have been proposed as conduit for ATP secretion: pannexin channels, connexin hemichannels, and calcium homeostasis modulator 1 (CALHM1) channels. In heterologous expression systems, these channels mediate outwardly rectifying membrane currents with distinct biophysical and pharmacological properties. I therefore tested whether also salt-detecting taste cells were endowed with these currents. To this aim, I applied the patch-clamp techniques to single cells in isolated taste buds from rat fungiform papillae. Salt-detecting cells were functionally identified by exploiting the effect of amiloride, which induces a current response by shutting down ENaCs. I looked for the presence of outwardly rectifying currents by using appropriate voltage-clamp protocols and specific pharmacological tools. I found that indeed salt-detecting cells possessed these currents with properties consistent with the presence, at least in part, of CALHM1 channels. Unexpectedly, CALHM1-like currents in taste cells were potentiated by known blockers of pannexin, suggesting a possible inhibitory action of this protein on CALMH1. These findings indicate that communication between salt-detecting cells and nerve endings might involve ATP release by CALMH1 channels. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Differential calcium sensitivity in NaV 1.5 mixed syndrome mutants.

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Abdelsayed, Mena; Baruteau, Alban-Elouen; Gibbs, Karen; Sanatani, Shubhayan; Krahn, Andrew D; Probst, Vincent; Ruben, Peter C

2017-09-15

SCN5a mutations may express gain-of-function (Long QT Syndrome-3), loss-of-function (Brugada Syndrome 1) or both (mixed syndromes), depending on the mutation and environmental triggers. One such trigger may be an increase in cytosolic calcium, accompanying exercise. Many mixed syndromes mutants, including ∆KPQ, E1784K, 1795insD and Q1909R, are found in calcium-sensitive regions. Elevated cytosolic calcium attenuates gain-of-function properties in ∆KPQ, 1795insD and Q1909R, but not in E1784K. By contrast, elevated cytosolic calcium further exacerbates gain-of-function in E1784K by destabilizing slow inactivation. Action potential modelling, using a modified O'Hara Rudy model, suggests that elevated heart rate rescues action potential duration in ∆KPQ, 1795insD and Q1909R, but not in E1784K. Action potential simulations suggest that E1784K carriers have an increased intracellular sodium-to-calcium ratio under bradycardia and tachycardia conditions. Elevated cytosolic calcium, which is common during high heart rates, ameliorates or exacerbates the mixed syndrome phenotype depending on the genetic signature. Inherited arrhythmias may arise from mutations in the gene for SCN5a, which encodes the cardiac voltage-gated sodium channel, Na V 1.5. Mutants in Na V 1.5 result in Brugada Syndrome (BrS1), Long-QT Syndrome (LQT3) or mixed syndromes (an overlap of BrS1/LQT3). Exercise is a potential arrhythmogenic trigger in mixed syndromes. We aimed to determine the effects of elevated cytosolic calcium, which is common during exercise, in mixed syndrome Na V 1.5 mutants. We used whole-cell patch clamp to assess the biophysical properties of Na V 1.5 wild-type (WT), ∆KPQ, E1784K, 1795insD and Q1909R mutants in human embryonic kidney 293 cells transiently transfected with the Na V 1.5 α subunit (WT or mutants), β1 subunit and enhanced green fluorescent protein. Voltage-dependence and kinetics were measured at cytosolic calcium levels of approximately 0, 500 and 2500�

Intracellular sodium hydrogen exchange inhibition and clinical myocardial protection.

Science.gov (United States)

Mentzer, Robert M; Lasley, Robert D; Jessel, Andreas; Karmazyn, Morris

2003-02-01

Although the mechanisms underlying ischemia/reperfusion injury remain elusive, evidence supports the etiologic role of intracellular calcium overload and oxidative stress induced by reactive oxygen species. Activation of the sodium hydrogen exchanger (NHE) is associated with intracellular calcium accumulation. Inhibition of the NHE-1 isoform may attenuate the consequences of this injury. Although there is strong preclinical and early clinical evidence that NHE inhibitors may be cardioprotective, definitive proof of this concept in humans awaits the results of ongoing clinical trials.

Paradoxical Effects of Sodium-Calcium Exchanger Inhibition on Torsade de Pointes and Early Afterdepolarization in a Heart Failure Rabbit Model.

Science.gov (United States)

Chang, Po-Cheng; Lu, Yu-Ying; Lee, Hui-Ling; Lin, Shien-Fong; Chu, Yen; Wen, Ming-Shien; Chou, Chung-Chuan

2018-05-03

Calcium homeostasis plays an important role in development of early afterdepolarizations (EADs) and torsade de pointes (TdP). The role of sodium-calcium exchanger (NCX) inhibition in genesis secondary Ca rise and EADs-TdP is still debated. Dual voltage and intracellular Ca optical mapping were conducted in 6 control and 9 failing rabbit hearts. After baseline electrophysiological and optical mapping studies, E4031 was given to simulate long QT syndrome. ORM-10103 was then administrated to examine the electrophysiological effects on EAD-TdP development. E4031 enhanced secondary Ca rise, EADs development and TdP inducibility in both control and failing hearts. The results showed that ORM-10103 reduced premature ventricular beats (PVBs) but was unable to suppress the inducibility of TdP or EADs. The electrophysiological effects of ORM-10103 included prolongation of action potential duration (APD) and increased APD heterogeneity in failing hearts. ORM10103 had a neutral effect on the amplitude of secondary Cai rise in control and HF groups. In this model, most EADs generated from the long-short APD junction area. In conclusion, highly selective NCX inhibition with ORM-10103 reduced PVB burden but was unable to suppress secondary Ca rise, EADs development nor inducibility of TdP. The possible electrophysiological mechanisms include APD prolongation and increased APD heterogeneity.

Pulsed laser deposited amorphous chalcogenide and alumino-silicate thin films and their multilayered structures for photonic applications

Energy Technology Data Exchange (ETDEWEB)

Němec, P. [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Charrier, J. [FOTON, UMR CNRS 6082, Enssat, 6 rue de Kerampont, BP 80518, 22305 Lannion (France); Cathelinaud, M. [Missions des Ressources et Compétences Technologiques, UPS CNRS 2274, 92195 Meudon (France); Allix, M. [CEMHTI-CNRS, Site Haute Température, Orléans (France); Adam, J.-L.; Zhang, S. [Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex (France); Nazabal, V., E-mail: virginie.nazabal@univ-rennes1.fr [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Equipe Verres et Céramiques, UMR-CNRS 6226, Sciences Chimiques de Rennes (SCR), Université de Rennes 1, 35042 Rennes Cedex (France)

2013-07-31

Amorphous chalcogenide and alumino-silicate thin films were fabricated by the pulsed laser deposition technique. Prepared films were characterized in terms of their morphology, chemical composition, and optical properties. Multilayered thin film stacks for reflectors and vertical microcavities were designed for telecommunication wavelength and the window of atmosphere transparency (band II) at 1.54 μm and 4.65 μm, respectively. Bearing in mind the benefit coming from the opportunity of an efficient wavelength tuning or, conversely, to stabilize the photoinduced effects in chalcogenide films as well as to improve their mechanical properties and/or their chemical durability, several pairs of materials from pure chalcogenide layers to chalcogenide/oxide layers were investigated. Different layer stacks were fabricated in order to check the compatibility between dissimilar materials which can have a strong influence on the interface roughness, adhesion, density, and homogeneity, for instance. Three different reflector designs were formulated and tested including all-chalcogenide layers (As{sub 40}Se{sub 60}/Ge{sub 25}Sb{sub 5}S{sub 70}) and mixed chalcogenide-oxide layers (As{sub 40}Se{sub 60}/alumino-silicate and Ga{sub 10}Ge{sub 15}Te{sub 75}/alumino-silicate). Prepared multilayers showed good compatibility between different material pairs deposited by laser ablation despite the diversity of chemical compositions. As{sub 40}Se{sub 60}/alumino-silicate reflector showed the best parameters; its stop band (R > 97% at 8° off-normal incidence) has a bandwidth of ∼ 100 nm and it is centered at 1490 nm. The quality of the different mirrors developed was good enough to try to obtain a microcavity structure for the 1.5 μm telecommunication wavelength made of chalcogenide layers. The microcavity structure consists of Ga{sub 5}Ge{sub 20}Sb{sub 10}S{sub 65} (doped with 5000 ppm of Er{sup 3+}) spacer surrounded by two 10-layer As{sub 40}Se{sub 60}/Ge{sub 25}Sb{sub 5}S{sub 70

Development of a New Ferrous Aluminosilicate Refractory Material for Investment Casting of Aluminum Alloys

Science.gov (United States)

Yuan, Chen; Jones, Sam; Blackburn, Stuart

2012-12-01

Investment casting is a time-consuming, labour intensive process, which produces complex, high value-added components for a variety of specialised industries. Current environmental and economic pressures have resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Alumino-silicate based refractories are commonly used as both filler and stucco materials for ceramic shell production. A new ceramic material, norite, is now being produced based on ferrous aluminosilicate chemistry, having many potential advantages when used for the production of shell molds for casting aluminum alloy. This paper details the results of a direct comparison made between the properties of a ceramic shell system produced with norite refractories and a typical standard refractory shell system commonly used in casting industry. A range of mechanical and physical properties of the systems was measured, and a full-scale industrial casting trial was also carried out. The unique properties of the norite shell system make it a promising alternative for casting aluminum based alloys in the investment foundry.

Reference values for urinary oxalate, calcium, citrate, uric acid, phosphate, magnesium, sulphate and sodium in biochemistry students at Universidad Nacional del Litoral, Argentina

Directory of Open Access Journals (Sweden)

Verónica Fernández

2017-10-01

Full Text Available Introduction: Urolithiasis (UL is a common disease whose incidence increased in the last quarter of the twentieth century. Metabolic evaluation is necessary for diagnosis, which requires the establishment of reference values (RV for the population in question. Objective: To determine the RV for calcium, oxalate, citrate, uric acid, phosphate, magnesium, sulphate and sodium in 24-hour urine belonging to students from the School of Biochemistry and Biological Sciences at Universidad Nacional del Litoral, province of Santa Fe, Argentina. Once RV were established, a frequency of alterations was determined and then compared with literature data. Methods: The NCCLSC28-A3 guideline (2008 was used. The study group included 69 students. The enzymatic colorimetric method, a Metrolab 1600 plus spectrophotometer and a DIESTRO ionselective electrode were also employed. Results: The RV found (95 % CI were the following: oxalate, 1.96-45.08; calcium, 20.65-250.74; citrate, 112.78-666.01; uric acid, 58.73-782.17; phosphate, 238.37-1051.44; magnesium, 28.7-146.67, all these values expressed as mg/24h; sulphate, 3.15-25.18 mmol/24h, and sodium, 42.81-285.3 mEq/24h. These findings emerged as well: hyperoxaluria, 3 %; hypercalciuria 12 %; hypocitraturia, 3 %; hyperuricosuria, 6 %; hyperphosphaturia, 6 %; hypomagnesuria, 6 %; hypernatriuria, 7 %, and hypersulphaturia, 0 %. When RV were compared, some analyte levels were similar and others showed a considerable difference. Conclusions: The diagnosis of UL through the study of metabolic changes is different according to the reference value used. Applying reference values established for other populations, including those of commercial kits manufacturers, may lead to a diagnosis which does not match the clinical condition of the patient.

Immobilization of myoglobin in sodium alginate composite membranes

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Katia Cecília de Souza Figueiredo

2015-06-01

Full Text Available AbstractThe immobilization of myoglobin in sodium alginate films was investigated with the aim of evaluating the protein stability in an ionic polymeric matrix. Myoglobin was chosen due to the resemblance to each hemoglobin tetramer. Sodium alginate, being a natural polysaccharide, was selected as the polymeric matrix because of its chemical structure and film-forming ability. To improve the mechanical resistance of sodium alginate films, the polymer was deposited over the surface of a cellulose acetate support by means of ultrafiltration. The ionic crosslink of sodium alginate was investigated by calcium ions. Composite membrane characterization comprised water swelling tests, water flux, SEM images and UV-visible spectroscopy. The electrostatic interaction between the protein and the polysaccharide did not damage the UV-visible pattern of native myoglobin. A good affinity between sodium alginate and cellulose acetate was observed. The top layer of the dense composite membrane successfully immobilized Myoglobin, retaining the native UV-visible pattern for two months.

Synthesis, characterization, and in vitro release of diclofenac sodium from hybrid nanostructured magnetite–calcium pectinate

International Nuclear Information System (INIS)

Dutta, Raj Kumar; Sahu, Saurabh; Reddy, V. R.

2012-01-01

A stable spherical nanostructured calcium pectinate loaded with diclofenac sodium (DS) and functionalized by superparamagnetic iron oxide nanoparticles, referred as MCPDS, was developed as a potential magnetically targeted drug delivery system. The sizes of the MCPDS were in the range of 100–200 nm in dried condition, confirmed by scanning electron microscopy and transmission electron microscopy. In the aqueous medium, the sizes of MCPDS were in the range 300 ± 50 nm, measured by dynamic light scattering technique. The X-ray diffraction and 57 Fe Mössbauer spectroscopy confirmed magnetite phase in MCPDS. The magnetic property of the MCPDS nanostructures was confirmed from high saturation magnetization (44.05 emu/g), measured using a vibrating sample magnetometer. The superparamagnetic property of MCPDS was characterized by superconducting quantum unit interference device magnetometry and corroborated by Mössbauer spectroscopy. The loading efficiency of DS in MCPDS was measured by UV–Vis spectrophotometry and corroborated by thermal analysis. The in vitro release of the drug from MCPDS in simulated gastrointestinal fluids and in phosphate buffer solution was found to be pH sensitive and exhibited sustained release property. The cumulative drug release agreed well with that of swelling controlled diffusion mechanism, given by the Korsemeyer Peppas model.

Synthesis, characterization, and in vitro release of diclofenac sodium from hybrid nanostructured magnetite-calcium pectinate

Energy Technology Data Exchange (ETDEWEB)

Dutta, Raj Kumar, E-mail: duttafcy@iitr.ernet.in; Sahu, Saurabh, E-mail: saurabhsahu12@gmail.com [Indian Institute of Technology Roorkee, Analytical Chemistry Laboratory, Department of Chemistry (India); Reddy, V. R., E-mail: vrreddy@csr.res.in [UGC-DAE Consortium for Scientific Research (India)

2012-08-15

A stable spherical nanostructured calcium pectinate loaded with diclofenac sodium (DS) and functionalized by superparamagnetic iron oxide nanoparticles, referred as MCPDS, was developed as a potential magnetically targeted drug delivery system. The sizes of the MCPDS were in the range of 100-200 nm in dried condition, confirmed by scanning electron microscopy and transmission electron microscopy. In the aqueous medium, the sizes of MCPDS were in the range 300 {+-} 50 nm, measured by dynamic light scattering technique. The X-ray diffraction and {sup 57}Fe Moessbauer spectroscopy confirmed magnetite phase in MCPDS. The magnetic property of the MCPDS nanostructures was confirmed from high saturation magnetization (44.05 emu/g), measured using a vibrating sample magnetometer. The superparamagnetic property of MCPDS was characterized by superconducting quantum unit interference device magnetometry and corroborated by Moessbauer spectroscopy. The loading efficiency of DS in MCPDS was measured by UV-Vis spectrophotometry and corroborated by thermal analysis. The in vitro release of the drug from MCPDS in simulated gastrointestinal fluids and in phosphate buffer solution was found to be pH sensitive and exhibited sustained release property. The cumulative drug release agreed well with that of swelling controlled diffusion mechanism, given by the Korsemeyer Peppas model.

Synthesis, characterization, and in vitro release of diclofenac sodium from hybrid nanostructured magnetite-calcium pectinate

Science.gov (United States)

Dutta, Raj Kumar; Sahu, Saurabh; Reddy, V. R.

2012-08-01

A stable spherical nanostructured calcium pectinate loaded with diclofenac sodium (DS) and functionalized by superparamagnetic iron oxide nanoparticles, referred as MCPDS, was developed as a potential magnetically targeted drug delivery system. The sizes of the MCPDS were in the range of 100-200 nm in dried condition, confirmed by scanning electron microscopy and transmission electron microscopy. In the aqueous medium, the sizes of MCPDS were in the range 300 ± 50 nm, measured by dynamic light scattering technique. The X-ray diffraction and 57Fe Mössbauer spectroscopy confirmed magnetite phase in MCPDS. The magnetic property of the MCPDS nanostructures was confirmed from high saturation magnetization (44.05 emu/g), measured using a vibrating sample magnetometer. The superparamagnetic property of MCPDS was characterized by superconducting quantum unit interference device magnetometry and corroborated by Mössbauer spectroscopy. The loading efficiency of DS in MCPDS was measured by UV-Vis spectrophotometry and corroborated by thermal analysis. The in vitro release of the drug from MCPDS in simulated gastrointestinal fluids and in phosphate buffer solution was found to be pH sensitive and exhibited sustained release property. The cumulative drug release agreed well with that of swelling controlled diffusion mechanism, given by the Korsemeyer Peppas model.

Comparative evaluation of calcium hypochlorite and sodium hypochlorite on soft-tissue dissolution.

Science.gov (United States)

Dutta, Arindam; Saunders, William P

2012-10-01

The aim of this study was to compare in vitro the tissue-dissolution properties of 5% and 10% calcium hypochlorite (Ca(OCl)(2)) with two concentrations (1.36% and 4.65%) of proprietary sodium hypochlorite (NaOCl) on bovine muscle tissue. The available chlorine concentration of each solution was determined using iodometric titration. Tissue specimens from bovine muscle were weight adjusted (50 ± 5 mg). Ten tissue specimens in each group were immersed in 5 mL each test solution, removed after 5 minutes, blotted dry, and weighed. The process was repeated every 5 minutes with a fresh 5-mL aliquot of the test solution for 60 minutes or until complete tissue dissolution, whichever was quickest. The percentage weight loss of the specimens was calculated over the experimental period. Available chlorine concentrations of the irrigants ranged from 1.36% to 4.65%. All solutions dissolved tissue completely after 60 minutes except 5% Ca(OCl)(2) (99.4% dissolution). Between the 35- and 60-minute test readings, there were no significant differences between the solutions. Chlorax (4.65% NaOCl) (Cerkamed Group, Nisko, Poland) dissolved tissue quicker during the first 35 minutes (P Tesco bleach (1.36% NaOCl) (Tesco Stores Ltd, Chestnut, UK) in the first 35 minutes except at the 5-minute measurement. Within the limitations of this study, Chlorax (4.65% NaOCl) dissolved tissue faster than the Ca(OCl)(2) solutions and Tesco thin bleach (1.36% NaOCl) over the first 35 minutes, but there were no significant differences among the solutions thereafter. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Pet food safety: sodium in pet foods.

Science.gov (United States)

Chandler, Marjorie L

2008-08-01

Healthy dogs and cats appear to be able to adjust to differing amounts of sodium in their diet via the rennin-angiotensin-aldosterone mechanisms. There is no strong evidence that increased dietary sodium increases the risk of hypertension in dogs and cats, and the current recommendation for hypertensive animals is to avoid high dietary salt intake without making a specific effort to restrict it. The prevalence of salt sensitivity and its effect on blood pressure has not been determined for cats or dogs. The ideal amount of sodium in the diet of dogs and cats with cardiac deficiency has not been determined, as increasing may detrimentally increase the extracellular fluid volume, but decreasing it may detrimentally increase the activation of the rennin-angiotensin-aldosterone system. Increased dietary sodium increases urine output and may decrease the risk of forming calcium oxalate uroliths due to the decrease in relative supersaturation of solutes. However, caution should be used in increasing the sodium intake of patients with renal disease as increased dietary sodium may have a negative effect on the kidneys independent of any effect on blood pressure.

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

Science.gov (United States)

Zhang, Long; Liu, Peng

2008-08-01

The uniform polyaniline (PANI) nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conductivity of the PANI nanotubes was found to be 1.752 × 10-5 (Ω·cm)-1.

Properties of Nanocrystals-formulated Aluminosilicate Bricks

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Francesca Conciauro

2015-10-01

insulating and/or mechanical properties. The nanocrystals- modified refractories showed variations in properties, with respect to the untreated aluminosilicate reference in heat- insulating performances (thermal diffusivities were measured by the “hot disk” technique. In general, they also showed improvements in mechanical compression resist‐ ance for all of the samples at 2 wt. %. The best heat insula‐ tion was obtained with the addition of nano-aluminium hydroxide at 2 wt. %, while the highest mechanical compres‐ sion breaking resistance was found with nano-CaCO3 at 2 wt. %. These outcomes were investigated with complemen‐ tary techniques, like mercury porosimetry for porosity, and Archimedes methods to measure physical properties like the bulk and apparent densities, apparent porosities and water absorption. The results show that the nano-alumini‐ um hydroxide modified bricks were the most porous, which could explain the best heat-insulating performances. There is a less straightforward explanation for the mechanical resistance results, as they may have relations with the characteristics of the pores. Furthermore, the nanoparti‐ cles may have possible reactions with the matrix during the heat treatments.

The effect of zeolite treatment by acids on sodium adsorption ratio of coal seam gas water.

Science.gov (United States)

Wang, Xiaoyu; Ozdemir, Orhan; Hampton, Marc A; Nguyen, Anh V; Do, Duong D

2012-10-15

Many coal seam gas (CSG) waters contain a sodium ion concentration which is too high relative to calcium and magnesium ions for environment acceptance. Natural zeolites can be used as a cheap and effective method to control sodium adsorption ratio (SAR, which is a measure of the relative preponderance of sodium to calcium and magnesium) due to its high cation exchange capacity. In this study, a natural zeolite from Queensland was examined for its potential to treat CSG water to remove sodium ions to lower SAR and reduce the pH value. The results demonstrate that acid activated zeolite at 30%wt solid ratio can reduce the sodium content from 563.0 to 182.7 ppm; the pH from 8.74 to 6.95; and SAR from 70.3 to 18.5. Based on the results of the batch experiments, the sodium adsorption capacity of the acid-treated zeolite is three times greater than that of the untreated zeolite. Both the untreated and acid-treated zeolite samples were characterized using zeta potential, surface characterization, DTA/TG and particle size distribution in order to explain their adsorption behaviours. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dietary sodium restriction in the prophylaxis of hypertensive disorders of pregnancy: effects on the intake of other nutrients.

Science.gov (United States)

van Buul, B J; Steegers, E A; Jongsma, H W; Rijpkema, A L; Eskes, T K; Thomas, C M; Baadenhuysen, H; Hein, P R

1995-07-01

Dietary sodium restriction is used in the Netherlands in the prophylaxis of preeclampsia. To study the effects of long-term sodium restriction on the intake of other nutrients and the outcome of pregnancy, 68 healthy nulliparous pregnant women were randomly assigned to either a low-sodium diet (20 mmol/24 h) or an unrestricted diet. The diet was consumed between week 14 of gestation and delivery. The dietary intakes of energy, fat, protein, carbohydrate, sodium, potassium, and calcium were estimated with the dietary-history technique. A low-sodium diet reduced the intake of protein (by approximately 15 g/24 h), fat (by 20 g/24 h), and calcium (by 350 mg/24 h) and tended to decrease the energy intake (by approximately 0.7 MJ/24 h). The intakes of carbohydrate and potassium did not differ between the groups. The maternal weight gain was less in the low-sodium group (6.0 +/- 3.7 compared with 11.7 +/- 4.7 kg). Mean birth weight was not significantly different (3.2 +/- 0.5 compared with 3.4 +/- 0.5 kg).

Salt equivalence and temporal dominance of sensations of different sodium chloride substitutes in butter.

Science.gov (United States)

de Souza, Vanessa Rios; Freire, Tassyana Vieira Marques; Saraiva, Carla Gonçalves; de Deus Souza Carneiro, João; Pinheiro, Ana Carla Marques; Nunes, Cleiton Antônio

2013-08-01

Studies indicate a positive association between dietary salt intake and some diseases, which has promoted the tendency to reduce the sodium in foods. The objective of this study was to determine the equivalent amount of different sodium chloride replacements required to promote the same degree of ideal saltiness in butter and to study the sensory profile of sodium chloride and the substitutes using the analysis of Temporal Dominance of Sensations (TDS). Using the magnitude estimation method, it was determined that the potencies of potassium chloride, monosodium glutamate and potassium phosphate relative to the 1% sodium chloride in butter are 83·33, 31·59 and 33·32, respectively. Regarding the sensory profile of the tested salt substitutes, a bitter taste was perceived in the butter with potassium chloride, a sour taste was perceived in the butter with potassium phosphate and sweet and umami tastes were dominant in the butter with monosodium glutamate. Of all the salt substitutes tested calcium lactate, potassium lactate, calcium chloride and magnesium chloride were impractical to use in butter.

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

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Zhang Long

2008-01-01

Full Text Available AbstractThe uniform polyaniline (PANI nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conductivity of the PANI nanotubes was found to be 1.752 × 10−5(Ω·cm−1.

Transformation kinetics in plasma-sprayed barium- and strontium-doped aluminosilicate (BSAS)

International Nuclear Information System (INIS)

Harder, B.J.; Faber, K.T.

2010-01-01

The hexacelsian-to-celsian phase transformation in Ba 1-x Sr x Al 2 Si 2 O 8 is of interest for environmental barrier coating applications. Plasma-sprayed microstructures were heat treated above 1100 o C and the kinetics of the hexacelsian-to-celsian transformation were quantified. Activation energies for bulk and crushed materials were determined to be ∼340 and ∼500 kJ mol -1 , respectively. X-ray diffraction and electron backscattered diffraction were used to establish how plasma spraying barium- and strontium-doped aluminosilicate effectively reduces the energy required for its transformation.

Effects of dietary clinoptilolite and calcium levels on the performance and egg quality of commercial layers

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DA Berto

2013-09-01

Full Text Available Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels - 2.5, 3.1, or 3.7% and four clinoptilolite levels - 0.0, 0.15, 0.25, or 0.50%, with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.

43. Calmodulin regulating calcium sensitivity of Na channels

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R. Vegiraju

2016-07-01

Full Text Available By extrapolating information from existing research and observing previous assumptions regarding the structure of the Na Channel, this experiment was conducted under the hypothesis that the Na Channel is in part regulated by the calmodulin protein, as a result proving calcium sensitivity of the Na Channel. Furthermore, we assume that there is a one to one stoichiometry between the Na Channel and the Calmodulin. There has been extensive research into the functionality and structure of sodium ion channels (Na channels, as several diseases are associated with the lack of regulation of sodium ions, that is caused by the disfunction of these Na channels. However, one highly controversial matter in the field is the importance of the protein calmodulin (CaM and calcium in Na channel function. Calmodulin is a protein that is well known for its role as a calcium binding messenger protein, and that association is believed to play an indirect role in regulating the Na channel through the Na channel’s supposed calcium sensitivity. While there are proponents for both sides, there has been relatively little research that provides strong evidence for either case. In this experiment, the effect of calmodulin on NaV 1.5 is tested by preparing a set of cardiac cells (of the human specie with the NaV 1.5 C-Termini and CaM protein, which were then to be placed in solutions with varying concentrations of calcium. We took special care to test multiple concentrations of calcium, as previous studies have tested very low concentrations, with Manu Ben-Johny’s team from the John Hopkins laboratory in particular testing up to a meager 50 micromolar, despite producing a well-respected paper (By comparison, the average Na channel can naturally sustain a concentration of almost 1-2 millimolar and on some occasions, reaching even higher concentrations. After using light scattering and observing the signals given off by the calcium interacting with these Nav1.5/Ca

ATP-dependent calcium transport across basal plasma membranes of human placental trophoblast

International Nuclear Information System (INIS)

Fisher, G.J.; Kelley, L.K.; Smith, C.H.

1987-01-01

As a first step in understanding the cellular basis of maternal-fetal calcium transfer, the authors examined the characteristics of calcium uptake by a highly purified preparation of the syncytiotrophoblast basal (fetal facing) plasma membrane. In the presence of nanomolar concentrations of free calcium, basal membranes demonstrated substantial ATP-dependent calcium uptake. This uptake required magnesium, was not significantly affected by Na + or K + (50 mM), or sodium azide (10 mM). Intravesicular calcium was rapidly and completely released by the calcium ionophore rapidly and completely released by the calcium ionophore A23187. Calcium transport was significantly stimulated by the calcium-dependent regulatory protein calmodulin. Placental membrane fractions enriched in endoplasmic reticulum (ER) and mitochondria also demonstrated ATP-dependent calcium uptake. In contrast to basal membrane, mitochondrial calcium uptake was completely inhibited by azide. The rate of calcium uptake was completely inhibited by azide. The rate of calcium uptake by the ER was only 20% of that of basal membranes. They conclude that the placental basal plasma membrane possesses a high-affinity calcium transport system similar to that found in plasma membranes of a variety of cell types. This transporter is situated to permit it to function in vivo in maternal-fetal calcium transfer

Untitled

Indian Academy of Sciences (India)

. Sodium metasilicate (2g), sodium aluminate (0.5g) and sodium hydroxide (0.7g) were mixed together and distilled water (50 ml) was added to the mixture to form a composite sodium aluminosilicate gel. Most of the runs were carried out by ...

Pump-induced refractive index changes in Tb{sup 3+} doped glasses

Energy Technology Data Exchange (ETDEWEB)

Vieira, T.A.; Santos, J.F.M. dos; Auad, Y.M; Nunes, L.A.O. [Instituto de Física de São Carlos, Universidade de São Paulo, SP (Brazil); Astrath, N.G.C; Baesso, M.L. [Departamento de Física, Universidade Estadual de Maringá, PR (Brazil); Catunda, T., E-mail: tomaz@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, SP (Brazil)

2016-01-15

It now well known in laser materials, that a refractive index change appears when the active ions are pumped from ground to excited state due to the polarizability difference between ground and excited states (metastable). In this paper this effect was investigated in Tb{sup 3+} doped glasses: calcium alumino phosphate (CAP), low-silica calcium aluminosilicate (LSCAS) and calcium aluminosilicate (CAS). The measurements were performed using the time resolved Z-scan technique, with an Ar{sup +} laser at 488 nm, close to the resonance of {sup 7}F{sub 6}→{sup 5}D{sub 4} absorption line, where {sup 5}D{sub 4} is a metastable state. We obtained for low-silica calcium aluminosilicate glass Δα{sub p}~10{sup −24} cm{sup 3} which is the highest value ever reported for a RE doped material. - Highlights: • Time resolved Z-scan measurements in 3 different Tb{sup 3+} doped glass. • Very high polarizability difference (Δα{sub p}), typically 1 order of magnitude higher than other rare earth ions. • Observations of higher order nonlinearities, such as-third, fifth and senventh order effects.

Modulation of intestinal absorption of calcium

Energy Technology Data Exchange (ETDEWEB)

Fournier, P; Dupuis, Y [Ecole Pratique des Hautes Etudes, 75 - Paris (France); Paris-11 Univ., 92 - Chatenay-Malabry (France))

1975-01-01

Absorption of ingested calcium (2ml of a 10mM CaCl/sub 2/ solution + /sup 45/Ca) by the adult rat was shown to be facilitated by the simultaneous ingestion of an active carbohydrate, L-arabinose. As the carbohydrate concentration is increased from 10 to 200mM, the absorption of calcium is maximised at a level corresponding to about twice the control absorption level. A similar doubling of calcium absorption is obtained when a 100mM concentration of any one of a number of other carbohydrates is ingested simultaneously with a 10mM CaCl/sub 2/ solution. Conversely, the simultaneous ingestion of increasing doses (10 to 100mM) of phosphate (NaH/sub 2/PO/sub 4/) with a 10mM CaCl/sub 2/ solution results in decreased /sup 45/Ca absorption and retention by the adult rat. The maximum inhibition of calcium absorption by phosphate is independent of the concentration of the ingested calcium solution (from 5 to 50mM CaCl/sub 2/). The simultaneous ingestion of CaCl/sub 2/ (10mM) with lactose and sodium phosphate (50 and 10mM respectively) shows that the activation effect of lactose upon /sup 45/Ca absorption may be partly dissimulated by the presence of phosphate. These various observations indicate that, within a large concentration range (2 to 50mM CaCl/sub 2/) calcium absorption appears to be a precisely modulated diffusion process. Calcium absorption varies (between minimum and maximum levels) as a function of the state of saturation by the activators (carbohydrates) and inhibitors (phosphate) of the calcium transport system.

Dissolution of lanthanide alumino-silicate oxynitride glasses

Science.gov (United States)

Bois, L.; Barré, N.; Guillopé, S.; Guittet, M. J.; Gautier-Soyer, M.; Duraud, J. P.; Trocellier, P.; Verdier, P.; Laurent, Y.

2000-01-01

The aqueous corrosion behavior of lanthanide aluminosilicate glasses has been studied under static conditions ( T=96°C, duration=1 and 3 months, glass surface area/leachate volume, S/ V=0.3 cm -1) by means of solution and solid analyses. It was found that these glasses exhibit a high chemical durability. The influence of yttrium, magnesium and nitrogen, which are supposed to improve the mechanical properties, on the chemical durability, has been investigated. After a one-month experiment, lanthanum and yttrium releases were found to be about 10 -7 mol l -1, while silicon and aluminum releases were about 10 -5 mol l -1. Yttrium seems to improve the chemical durability. The presence of nitrogen does not seem to modify the glass constituents releases, but seems to improve the surface state of the altered glass. XPS experiments reveal that lanthanum and yttrium are more concentrated near the surface (20-30 Å) of the glass after the leaching test.

Effect of Sodium Chloride Concentrations and Its Foliar Application Time on Quantitative and Qualitative Characteristics of Pomegranate Fruit (Punica granatum L. CV. “Malas Saveh”

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V. Rouhi

2016-02-01

Full Text Available Introduction: Pomegranate (Punica granatum L. belong to Punicaceae family is native to Iran and grown extensively in arid and semi-arid regions worldwide. Pomegranate is also important in human medicine and its components have a wide range of clinical applications. Cracking causes a major fruit loss, which is a serious commercial loss to farmers. Fruit cracking, seems to be a problem that lessens the marketability to a great extent. Fruit cracking is one of the physiological disorders wherever pomegranate trees are grown. It may be due to moisture imbalances as this fruit is very sensitive to variation in soil moisture prolonged drought causes hardening of skin and if this is followed by heavy irrigation the pulp grows then skin grows and cracks. Many factors i.e., climate, soil and irrigation, varieties, pruning, insects and nutrition statues influence the growth and production of fruit trees. Deficiencies of various nutrients are related to soil types, plants and even to various cultivars. Most nutrients are readily fixed in soil having different PH. Plant roots are unable to absorb these nutrients adequately from the dry topsoil. Foliar fertilization is particularly useful under conditions where the absorption of nutrients through the soil and this difficult situation to be present in the nutrients such as calcium. Since the calcium element is needed, so spraying them at the right time is correct way to save the plant requirements. Therefore, a research conducted on effect of sodium chloride concentrations and its foliar application time on quantitative and qualitative characteristics of pomegranate fruit (Punica granatum L. CV. “Malas Saveh”. Materials and Methods: An experiment conducted at Jarghoyeh, Esfahan, Iran in 2012. The factors were Sodium chloride (0, 5 and 10 g/L and times of spray (15, 45 and 75 days before harvest. The study was factorial experiment in the base of randomized complete blocks design with three replications

Estimation of salivary sodium, potassium, calcium, phosphorus and urea in type II diabetic patients.

Science.gov (United States)

Shirzaiy, Masoumeh; Heidari, Fatemeh; Dalirsani, Zohreh; Dehghan, Javid

2015-01-01

Diabetes mellitus is an endocrine disease due to insufficiency production of insulin that is associated with altered quantity and quality in salivary secretion. Alteration in saliva can reflect the changes in patients' blood. The collection of saliva is easy therefore; the assessment of saliva is suitable for screening tests of large population. The study aimed at evaluate some elements in diabetic patients' saliva. A total of 25 diabetic patients and age-sex matched control group enrolled into the study. Absorbance spectrophotometer technique was used for assessment of some salivary elements. The assessment of saliva showed that diabetics had unstimulated salivary flow rate of 0.18 ± 0.14 mL/min compared to 0.30 ± 0.12 mL/min for healthy individuals (Pdiabetics compared to healthy group (Psalivary urea, potassium and phosphorus was significantly elevated in diabetic males compared to healthy males and the level of salivary calcium in diabetic females was significantly reduced compared to healthy females (Psalivary sodium of healthy and diabetic persons according to gender (P>0.05). The finding showed that there were some alterations in salivary elements in diabetic patients even in well-controlled subjects compared to healthy group. Moreover, some salivary elements concentrations were various in diabetic and healthy subjects regarding to the sex. Assessment of salivary composition could be beneficial in oral health evaluation. Copyright © 2013 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Tipping Point for Expansion of Layered Aluminosilicates in Weakly Polar Solvents: Supercritical CO ₂

Energy Technology Data Exchange (ETDEWEB)

Schaef, Herbert T.; Loganathan, Narasimhan; Bowers, Geoffrey M.; Kirkpatrick, Robert J.; Yazaydin, A. O.; Burton, Sarah D.; Hoyt, David W.; Thanthiriwatte, Sahan; Dixon, David A.; McGrail, Bernard P.; Rosso, Kevin M.; Ilton, Eugene S.; Loring, John S.

2017-10-11

Layered aluminosilicates play a dominant role in the mechanical and gas storage properties of the subsurface, are used in diverse industrial applications, and serve as model materials for understanding solvent-ion-support systems. Although expansion in the presence of H2O is well known to be systematically correlated with the hydration free energy of the interlayer cation, in environments dominated by non-polar solvents (i.e. CO2), uptake into the interlayer is not well-understood. Using novel high pressure capabilities, we investigated the interaction of super-critical CO2 with Na+-, NH4+-, and Cs+-saturated montmorillonite, comparing results with predictions from molecular dynamics simulations. Despite the known trend in H2O, and that cation solvation energies in CO2 suggest a stronger interaction with Na+, both the NH4+- and Cs+-clays readily absorbed CO2 and expanded while the Na+-clay did not. The apparent inertness of the Na+-clay was not due to kinetics, as experiments seeking a stable expanded state showed that none exists. Molecular dynamics simulations revealed a large endothermicity to CO2 intercalation in the Na+-clay, but little or no energy barrier for the NH4+- and Cs+-clays. Consequently, we have shown for the first time that in the presence of a low dielectric constant gas swelling depends more on the strength of the interaction between interlayer cation and aluminosilicate sheets and less on that with solvent. The finding suggests a distinct regime in layered aluminosilicates swelling behavior triggered by low solvent polarizability, with important implications in geomechanics, storage and retention of volatile gases, and across industrial uses in gelling, decoloring, heterogeneous catalysis, and semi-permeable reactive barriers.

Levels of ammonium, sulfate, chloride, calcium, and sodium in snow and ice from southern Greenland

International Nuclear Information System (INIS)

Busenberg, E.; Langway, C.C. Jr.

1979-01-01

Chemical analysis of surface snows and dated ice core samples from Dye 3, Greenland, suggests that the ammonium cation is a major constituent in all samples and that the annual ammonium levels present in the south Greenland samples have varied from 3.3 to 26.3 μg/kg between the seventeenth century and the present time. The annual range of 1974--1975 surface samples was between 3.8 and 8.8 μg/kg, while the mean was 5.7 +- 1.8 μ/kg. The recent large-scale uses of fixed nitrogen fertilizers and industrial pollution have apparently not affected the levels of ammonia reaching southern Greenland. The sodium and chloride present are predominantly derived from ocean spray, while more than 90% of the calcium is of continental origin. The levels of these three elements have not apparently been affected by human activity since the industrial revolution. Sulfate levels have increased dramatically since the industrial revolution, suggesting that sulfate of anthropogenic origin is the most important source of sulfate in modern snows from southern Greenland. The amount of the sulfuric acid neutralized by the ammonium cations was approximately 100% in the seventeenth and eighteenth centuries, dropping to approximately 20% in the 1974--1975 samples. These figures imply that there has been in increase in the acidity of precipitation in southern Greenland since the end of the eighteenth ce

The effect of dentin on the pulp tissue dissolution capacity of sodium hypochlorite and calcium hydroxide.

Science.gov (United States)

Slutzky-Goldberg, Iris; Hanut, Aiham; Matalon, Shlomo; Baev, Valery; Slutzky, Hagay

2013-08-01

Sodium hypochlorite (NaOCl) and calcium hydroxide (Ca[OH]2) have tissue dissolution capacity. The aim of this study was to evaluate the potential effect of dentin on their tissue dissolution capacity in a novel dentin model. Dentin models were prepared from 25 freshly extracted human molar teeth; the crowns were separated from the roots, and a rectangular inner shape was prepared. Pulp tissue samples adjusted to similar weights of 6.5 ± 0.2 mg were randomly divided into 6 groups: NaOCl groups in test tubes or dentin models for 1 hour, Ca(OH)2 groups in test tubes or dentin models for 1 week, and control groups saline in test tubes or dentin models for 1 week. The final weights after the experimental period were checked and compared with the initial weights. The differences were statistically analyzed. The tissue dissolution capacity of Ca(OH)2 was affected by the presence of dentin. Similarly, NaOCl lost its effect on the pulp tissue after incubation in dentin. Comparison between all test groups showed highly significant differences (P interactions between local endodontic medicaments, dentin, and pulp tissue. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Calcium-dependent but calmodulin-independent protein kinase from soybean

International Nuclear Information System (INIS)

Harmon, A.C.; Putnam-Evans, C.; Cormier, M.J.

1987-01-01

A calcium-dependent protein kinase activity from suspension-cultured soybean cells (Glycine max L. Wayne) was shown to be dependent on calcium but not calmodulin. The concentrations of free calcium required for half-maximal histone H1 phosphorylation and autophosphorylation were similar (≥ 2 micromolar). The protein kinase activity was stimulated 100-fold by ≥ 10 micromolar-free calcium. When exogenous soybean or bovine brain calmodulin was added in high concentration (1 micromolar) to the purified kinase, calcium-dependent and -independent activities were weakly stimulated (≤ 2-fold). Bovine serum albumin had a similar effect on both activities. The kinase was separated from a small amount of contaminating calmodulin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. After renaturation the protein kinase autophosphorylated and phosphorylated histone H1 in a calcium-dependent manner. Following electroblotting onto nitrocellulose, the kinase bound 45 Ca 2+ in the presence of KCl and MgCl 2 , which indicated that the kinase itself is a high-affinity calcium-binding protein. Also, the mobility of one of two kinase bands in SDS gels was dependent on the presence of calcium. Autophosphorylation of the calmodulin-free kinase was inhibited by the calmodulin-binding compound N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7), showing that the inhibition of activity by W-7 is independent of calmodulin. These results show that soybean calcium-dependent protein kinase represents a new class of protein kinase which requires calcium but not calmodulin for activity

Preparation of ultra-fine calcium carbonate by a solvent-free reaction using supersonic airflow and low temperatures

OpenAIRE

Cai, Yan-Hua; Ma, Dong-Mei; Peng, Ru-Fang; Chu, Shi-Jin

2008-01-01

The treatment of calcium chloride with sodium carbonate under solvent-free conditions with a supersonic airflow and at a low heating temperature leads to the synthesis of ultra-fine calcium carbonate. The reaction not only involves mild conditions, a simple operation, and high yields but also gives a high conversion rate.

Variations in Calcium and Alginate Ions Concentration in Relation to the Properties of Calcium Alginate Nanoparticles

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Hamed Daemi

2013-05-01

Full Text Available Alginate belongs to a group of natural polymers called polysaccharides. They have carboxylic functional groups beside hydroxyls which are common in all polysaccharides. These materials show interesting properties due to theirfunctional groups. One of these properties is the ability of this polymer as a suitable carrier of protecting and transferring drugs and biomolecules. The particle sizes of these polymers are very important for their applications, so different techniques were used for preparation of these materials. In this way polymeric nanoparticles of calcium alginate which are excellent carriers in drug delivery systems were prepared by addition of calcium chloride solution to dilute solution of sodium alginate. Investigation of the size and distribution of nanoparticles were analyzed by SEM method. The concentration effects of both alginate and calcium ions on the size and distribution of  nanoparticles were studied in this research. Results showed that the size of nanoparticles obviously decreased with decreasing polymeric alginate concentration because of lower active sites in polymer chain. On the other hand, thesize and distribution of nanoparticles are significantly improved with increase of calcium cation concentrations. The mean particle size 40-70 nm and spherical shape are the main characteristics of the prepared nanoparticles.

Effects of dietary interventions on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones

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Mustafa Kıraç

2013-02-01

Full Text Available The aim of this study is to investigate the effects of dietary factors on 24-hour urine parameters in patients with idiopathic recurrent calcium oxalate stones. A total of 108 of idiopathic recurrent calcium oxalate stones were included in the study. A 24-hour urinalysis was performed and metabolic abnormalities were measured for all of the patients. All of the patients were given specialized diets for their 24-hour urine abnormalities. At the end of first month, the same parameters were examined in another 24-hour urinalysis. Hyperoxaluria, hypernatruria, and hypercalciuria were found in 84 (77%, 43 (39.8%, and 38 (35.5% of the patients, respectively. The differences between the oxalate, sodium, volume, uric acid, and citrate parameters before and after the dietary intervention were significant (p < 0.05. The calcium parameters were not significantly different before and after the intervention. We found that oxalate, sodium, volume, uric acid, and citrate—but not calcium—abnormalities in patients with recurrent calcium oxalate stones can be corrected by diet. The metabolic profiles of idiopathic calcium oxalate stone patients should be evaluated and the appropriate dietary interventions should be implemented to decrease stone recurrence.

Study of mechanical properties of calcium phosphate cement with addition of sodium alginate and dispersant; Estudo das propriedades mecanicas de cimento de fosfato de calcio com adicao de alginato de sodio e defloculante

Energy Technology Data Exchange (ETDEWEB)

Fernandes, J.M.; Coelho, W.T.; Thurmer, M.B.; Vieira, P.S.; Santos, L.A., E-mail: julianafernandes2@yahoo.com.br [Universidade Federal do Rio Grande do Sul (UFRS), RS (Brazil)

2011-07-01

Several studies in literature have shown that the addition of polymer additives and deflocculant has a strong influence on the mechanical properties of cements in general.The low mechanical strength is the main impediment to wider use of bone cement of calcium phosphate (CFCs) as the implant material, since they have mechanical strength which equals the maximum of trabecular bone.In order to evaluate the strength of a CFC compound alpha-tricalcium phosphate, sodium alginate were added (1%, 2% and 3% by weight) and dispersant ammonium polyacrylate (3%) in aqueous solution.Specimens were made and evaluated for density, porosity, crystalline phases and mechanical strength.The results show the increase of the mechanical properties of cement when added sodium alginate and dispersant. (author)

Calcium release rates from tooth enamel treated with dentifrices containing whitening agents and abrasives.

Science.gov (United States)

Araujo, Danilo Barral; Silva, Luciana Rodrigues; de Araujo, Roberto Paulo Correia

2010-01-01

Tooth whitening agents containing hydrogen peroxide and carbamide peroxide are used frequently in esthetic dental procedures. However, lesions on the enamel surface have been attributed to the action of these products. Using conventional procedures for separating and isolating biological structures, powdered enamel was obtained and treated with hydrogen peroxide, carbamide peroxide, and sodium bicarbonate, ingredients typically found in dentifrices. The enamel was exposed to different pH levels, and atomic emission spectrometry was used to determine calcium release rates. As the pH level increased, the rate of calcium release from enamel treated with dentifrices containing whitening agents decreased. Carbamide peroxide produced the lowest amount of decalcification, while sodium bicarbonate produced the highest release rates at all pH levels.

Crystallization of calcium oxalate in minimally diluted urine

Science.gov (United States)

Bretherton, T.; Rodgers, A.

1998-09-01

Crystallization of calcium oxalate was studied in minimally diluted (92%) urine using a mixed suspension mixed product crystallizer in series with a Malvern particle sizer. The crystallization was initiated by constant flow of aqueous sodium oxalate and urine into the reaction vessel via two independent feed lines. Because the Malvern cell was in series with the reaction vessel, noninvasive measurement of particle sizes could be effected. In addition, aliquots of the mixed suspension were withdrawn and transferred to a Coulter counter for crystal counting and sizing. Steady-state particle size distributions were used to determine nucleation and growth kinetics while scanning electron microscopy was used to examine deposited crystals. Two sets of experiments were performed. In the first, the effect of the concentration of the exogenous sodium oxalate was investigated while in the second, the effect of temperature was studied. Calcium oxalate nucleation and growth rates were found to be dependent on supersaturation levels inside the crystallizer. However, while growth rate increased with increasing temperature, nucleation rates decreased. The favored phases were the trihydrate at 18°C, the dihydrate at 38° and the monohydrate at 58°C. The results of both experiments are in agreement with those obtained in other studies that have been conducted in synthetic and in maximally diluted urine and which have employed invasive crystal counting and sizing techniques. As such, the present study lends confidence to the models of urinary calcium oxalate crystallization processes which currently prevail in the literature.

Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

Energy Technology Data Exchange (ETDEWEB)

Wurth, R. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Pascual, M.J., E-mail: mpascual@icv.csic.es [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Mather, G.C.; Pablos-Martin, A.; Munoz, F.; Duran, A. [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Cuello, G.J. [Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France); Ruessel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

2012-06-15

A base glass of composition 3.5 Li{sub 2}O Bullet-Operator 0.15 Na{sub 2}O Bullet-Operator 0.2 K{sub 2}O Bullet-Operator 1.15 MgO Bullet-Operator 0.8 BaO Bullet-Operator 1.5 ZnO Bullet-Operator 20 Al{sub 2}O{sub 3} Bullet-Operator 67.2 SiO{sub 2} Bullet-Operator 2.6 TiO{sub 2} Bullet-Operator 1.7 ZrO{sub 2} Bullet-Operator 1.2 As{sub 2}O{sub 3} (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi{sub 2}O{sub 6} with nanoscaled crystals forms at 750 Degree-Sign C. Quantitative Rietveld refinement of samples annealed at 750 Degree-Sign C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, {beta}-eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. The Avrami parameter (n {approx} 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 {+-} 20 kJ mol{sup -1}. - Highlights: Black-Right-Pointing-Pointer Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. Black-Right-Pointing-Pointer Combined X-ray and neutron diffraction structural refinement. Black-Right-Pointing-Pointer {beta}-Eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. Black-Right-Pointing-Pointer 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. Black-Right-Pointing-Pointer Usage and validation of an alternative approach to calculate the Avrami parameter.

Oxalate molecule as the trap for gamma-irradiation energy in the amorphous aluminosilicate Al2(OH)6H4SiO4

International Nuclear Information System (INIS)

Nothig-Laslo, V.; Horvath, L.; Bilinski, H.

1990-01-01

Paramagnetic species which were the products of gamma irradiation at 77 K and at room temperature were studied by ESR spectroscopy in the amorphous aluminosilicate, Al2(OH)6H4SiO4, prepared in the presence and in the absence of oxalate ion. The aluminosilicate precipitated from the solution containing the oxalate ion in 10(-4) mol dm-3 concentration contained the oxalate only in trace amounts. When gamma-irradiated at 77 K and at room temperature, this compound gave the stable paramagnetic species represented by the single ESR line centered at g = 2.000. We ascribe this spectrum to the CO2- radical formed from the oxalate ion. The same aluminosilicate prepared in the absence of the oxalate either produced no stable paramagnetic product after gamma irradiation at room temperature or resulted in composite ESR spectra, indicating the presence of several paramagnetic species if irradiated at 77 K. Complex ESR spectra were transformed by heating to the stable paramagnetic centers which differed from the one obtained from oxalate ion. We conclude that in Al2(OH)6H4SiO4 oxalate acts as a trap for the gamma-radiation energy

Treatment with Potassium Bicarbonate Lowers Calcium Excretion and Bone Resorption in Older Men and Women

Science.gov (United States)

Dawson-Hughes, Bess; Harris, Susan S.; Palermo, Nancy J.; Castaneda-Sceppa, Carmen; Rasmussen, Helen M.; Dallal, Gerard E.

2009-01-01

Context: Bicarbonate has been implicated in bone health in older subjects on acid-producing diets in short-term studies. Objective: The objective of this study was to determine the effects of potassium bicarbonate and its components on changes in bone resorption and calcium excretion over 3 months in older men and women. Design, Participants, and Intervention: In this double-blind, controlled trial, 171 men and women age 50 and older were randomized to receive placebo or 67.5 mmol/d of potassium bicarbonate, sodium bicarbonate, or potassium chloride for 3 months. All subjects received calcium (600 mg of calcium as triphosphate) and 525 IU of vitamin D3 daily. Main Outcome Measures: Twenty-four-hour urinary N-telopeptide and calcium were measured at entry and after 3 months. Changes in these measures were compared across treatment groups in the 162 participants included in the analyses. Results: Bicarbonate affected the study outcomes, whereas potassium did not; the two bicarbonate groups and the two no bicarbonate groups were therefore combined. Subjects taking bicarbonate had significant reductions in urinary N-telopeptide and calcium excretion, when compared with subjects taking no bicarbonate (both before and after adjustment for baseline laboratory value, sex, and changes in urinary sodium and potassium; P = 0.001 for both, adjusted). Potassium supplementation did not significantly affect N-telopeptide or calcium excretion. Conclusions: Bicarbonate, but not potassium, had a favorable effect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults. PMID:18940881

Mechanisms of pyrethroid insecticide-induced stimulation of calcium influx in neocortical neurons

Science.gov (United States)

Pyrethroid insecticides bind to voltage-gated sodium channels (VGSCs) and modify their gating kinetics, thereby disrupting neuronal function. Pyrethroids have also been reported to alter the function of other channel types, including activation of voltage-gated Ca2+ calcium chann...

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

Science.gov (United States)

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

2014-06-01

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

Catalytic pyrolysis using UZM-44 aluminosilicate zeolite

Science.gov (United States)

Nicholas, Christopher P; Boldingh, Edwin P

2013-12-17

A new family of aluminosilicate zeolites designated UZM-44 has been synthesized. These zeolites are represented by the empirical formula Na.sub.nM.sub.m.sup.k+T.sub.tAl.sub.1-xE.sub.xSi.sub.yO.sub.z where "n" is the mole ratio of Na to (Al+E), M represents a metal or metals from zinc, Group 1, Group 2, Group 3 and or the lanthanide series of the periodic table, "m" is the mole ratio of M to (Al+E), "k" is the average charge of the metal or metals M, T is the organic structure directing agent or agents, and E is a framework element such as gallium. The process involves contacting a carbonaceous biomass feedstock with UZM-44 at pyrolysis conditions to produce pyrolysis gases comprising hydrocarbons. The catalyst catalyzes a deoxygenation reaction converting oxygenated hydrocarbons into hydrocarbons and removing the oxygen as carbon oxides and water. A portion of the pyrolysis gases is condensed to produce low oxygen biomass-derived pyrolysis oil.

Effect of Moisture Content of Chitin-Calcium Silicate on Rate of Degradation of Cefotaxime Sodium.

Science.gov (United States)

Al-Nimry, Suhair S; Alkhamis, Khouloud A

2018-04-01

Assessment of incompatibilities between active pharmaceutical ingredient and pharmaceutical excipients is an important part of preformulation studies. The objective of the work was to assess the effect of moisture content of chitin calcium silicate of two size ranges (two specific surface areas) on the rate of degradation of cefotaxime sodium. The surface area of the excipient was determined using adsorption method. The effect of moisture content of a given size range on the stability of the drug was determined at 40°C in the solid state. The moisture content was determined at the beginning and the end of the kinetic study using TGA. The degradation in solution was studied for comparison. Increasing the moisture content of the excipient of size range 63-180 μm (surface area 7.2 m 2 /g) from 3.88 to 8.06% increased the rate of degradation of the drug more than two times (from 0.0317 to 0.0718 h -1 ). While an opposite trend was observed for the excipient of size range moisture content moisture content of 8.54%, and the degradation in solid state at both moisture contents was higher than that in solution (0.0871 h -1 ). In conclusion, the rate of degradation in solid should be studied taking into consideration the specific surface area and moisture content of the excipient at the storage condition and it may be higher than that in solution.

The Effects of Bee Venom on PLA2 and Calcium Concentration in Raw 264.7 Cells

Directory of Open Access Journals (Sweden)

Jong-Il Yun

2003-06-01

Full Text Available Objectives : The purpose of this study was to investigate the effect of Bee Venom on the lipopolysaccharide, sodium nitroprusside and hydrogen peroxide induced expression phospholipase A2 and calcium concentration in RAW 264.7 cells, a murine macrophage cell line. Methods : The expression of phospholipase A2 was determined by western blotting with corresponding antibodies, and the generation of intracellular calcium concentration was investigated by delta scan system in RAW 264.7 cells. Results : 1. Compared with control, expressions of lipopolysaccharide-induced phospholipase A2 were decreased significantly by 1 ㎍/㎕ of bee venom and decreased by 0.5, 5 ㎍/㎕ of bee venom. 2. Compared with control, expressions of sodium nitroprusside-induced phospholipase A2 were decreased significantly by 5 ㎍/㎕ of bee venom but increased by 0.5, 5 ㎍/㎕ of bee venom. 3. Compared with control, expressions of hydrogen peroxide-induced phospholipase A2 were decreased significaltly by 1 ㎍/㎕ of bee venom and decreased by 0.5 ㎍/㎕ of bee venom but increased by 5 ㎍/㎕ of bee venom. 4. Compared with control, lipopolysaccharide, sodium nitroprusside and hydrogen peroxide- induced intracellular calcium concentrations were decreased by 0.5, 1, 5 ㎍/㎕ of bee venom and by indomethacin

Oxygen titration in sodium. The mercury method and its use for very low values; Dosage de l'oxygene dans le sodium. La methode au mercure : son utilisation dans le cas de tres faibles teneurs

Energy Technology Data Exchange (ETDEWEB)

Champeix, L; Darras, R; Duflo, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

The mercury method for the oxygen titration in sodium has now been known for ten years and is probably the more frequently used. In this text, precision are given to what extent it is valuable when used in microanalysis. Details are given on the apparatus, its manipulation and its calibration. After testing, we have decided to use flame spectroscopy to titrate the sodium hydroxide formed. Discussions are exposed on the errors due to the presence of sodium chloride and calcium. Results are examined from the point of view of their reproducibility and accuracy. If great care is taken, this method allows oxygen titration in sodium even for values below 10 ppm with satisfactory precision. (author) [French] La methode au mercure pour le dosage de l'oxygene dans le sodium est connue depuis une dizaine d'annees, elle est probablement la plus utilisee. Nous avons voulu preciser dans quelle mesure elle etait valable dans le domaine des faibles teneurs avec une precision acceptable. Nous decrivons en detail l'appareil utilise pour l'analyse, le mode operatoire et la methode d'etalonnage. Nos essais nous ont conduit a adopter la spectrographie de flamme pour le dosage de la soude formee, les erreurs introduites par la presence de chlorure de sodium et de calcium sont discutes. Les resultats obtenus sont examines du point de vue de la reproductibilite, de la justesse. Moyennant un mode operatoire tres soigne, cette methode permet le dosage de l'oxygene dans le sodium, meme a des teneurs inferieures a 10 ppm avec une precision satisfaisante. (auteur)

Analysis and differentiation of mineral dust by single particle laser mass spectrometry

International Nuclear Information System (INIS)

Gallavardin, S. J.; Lohmann, U.; Cziczo, Daniel J.

2008-01-01

This study evaluates the potential of single particle laser desorption/ionization mass spectrometry for the analysis of atmospherically relevant mineral dusts. Samples of hematite, goethite, calcium carbonate, calcium sulfate, silica, quartz, montmorrillonite, kaolinite, illite, hectorite, wollastonite and nephelinsyenit were investigated in positive and negative ion mode with a monopolar time-of-flight mass spectrometer where the desorption/ionization step was performed with a 193 nm excimer laser (∼10 9 W/cm 2 ). Particle size ranged from 500 nm to 3 (micro)m. Positive mass spectra mainly provide elemental composition whereas negative ion spectra provide information on element speciation and of a structural nature. The iron oxide, calcium-rich and aluminosilicate nature of particles is established in positive ion mode. The differentiation of calcium materials strongly relies on the calcium counter-ions in negative mass spectra. Aluminosilicates can be differentiated in both positive and negative ion mode using the relative abundance of various aluminum and silicon ions

Dietary calcium intake and risk of cardiovascular disease, stroke, and fracture in a population with low calcium intake.

Science.gov (United States)

Kong, Sung Hye; Kim, Jung Hee; Hong, A Ram; Cho, Nam H; Shin, Chan Soo

2017-07-01

Background: The role of dietary calcium intake in cardiovascular disease (CVD), stroke, and fracture is controversial. Most previous reports have evaluated populations with high calcium intake. Objective: We aimed to evaluate whether high dietary calcium intake was associated with the risk of CVD, stroke, and fracture in a population with low calcium intake. Design: In a prospective cohort study beginning in 2001 in Ansung-Ansan, Korea, 2158 men and 2153 women aged >50 y were evaluated for all-cause mortality, CVD, stroke, and fractures over a median 9-y follow-up. Results: During follow-up, 242 and 100 deaths, 149 and 150 CVD events, 58 and 82 stroke events, and 211 and 292 incident fractures occurred in men and women, respectively. The first quartiles of energy-adjusted dietary calcium intake were 249 mg/d (IQR: 169 mg/d) in men and 209 mg/d (IQR: 161 mg/d) in women. Both men and women with higher dietary calcium intake tended to have higher fat, protein, sodium, phosphorus, fruit, and vegetable intakes. In men, outcomes were not significantly associated with dietary calcium intake with or without adjustments, and CVD risk tended to increase with increasing energy-adjusted dietary calcium intake, but this was not statistically significant ( P = 0.078 and P = 0.093 with and without adjustment, respectively). In women, CVD risk and dietary calcium intake showed a U-shaped association; the HRs (95% CIs) without adjustment relative to the first quartile were 0.71 (0.47, 1.07), 0.57 (0.36, 0.88), and 0.52 (0.33, 0.83) for quartiles 2, 3, and 4, respectively, and the values after adjustment were 0.70 (0.45, 1.07), 0.51 (0.31, 0.81), and 0.49 (0.29, 0.83) for quartiles 2, 3, and 4, respectively. Conclusion: In Korean women, increased dietary calcium intake was associated with a decreased CVD risk, but it did not influence the risk of stroke or fracture. © 2017 American Society for Nutrition.

Physico-chemical impacts of cementitiously-derived calcium and silica on sodium montmorillonite

International Nuclear Information System (INIS)

Kinsela, Andrew S.; Tjitradjaja, Alice; Collins, Richard N.; Waite, T. David; Macdonald, Bennett C.T.; White, Ian; PAYNE, Timothy E.

2012-01-01

The storage of nuclear waste frequently involves the construction of a concrete encasement adjacent to an engineered clay barrier, which can expose the swelling clay to elevated concentrations of certain cations (particularly calcium) and very high alkalinity (pH 10 - 13). These conditions have the capacity to degrade the integrity of the clay layer and, as such, it is necessary to fully understand the effects of all possible biogeochemical interactions involved. In this study, the changes in hydraulic conductivities and other physico-chemical properties of Na-montmorillonite assemblages under the influence of both highly alkaline (pH 9 and 12) conditions and elevated concentrations of calcium and silica are examined. The Na-montmorillonite suspensions and filtration experimental method is presented, as well as the electrophoresis characterization technique

Characterization of transport of calcium by microsomal membranes from roots maize

International Nuclear Information System (INIS)

Vaughan, M.A.

1985-01-01

This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the 45 Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl 2 , 50 μM CaCl 2 , at 23 0 C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner

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

Science.gov (United States)

Akalın, A S; Unal, G; Dinkci, N; Hayaloglu, A A

2012-07-01

The influence of milk protein-based ingredients on the textural characteristics, sensory properties, and microstructure of probiotic yogurt during a refrigerated storage period of 28 d was studied. Milk was fortified with 2% (wt/vol) skim milk powder as control, 2% (wt/vol) sodium calcium caseinate (SCaCN), 2% (wt/vol) whey protein concentrate (WPC) or a blend of 1% (wt/vol) SCaCN and 1% (wt/vol) WPC. A commercial yogurt starter culture and Bifidobacterium lactis Bb12 as probiotic bacteria were used for the production. The fortification with SCaCN improved the firmness and adhesiveness. Higher values of viscosity were also obtained in probiotic yogurts with SCaCN during storage. However, WPC enhanced water-holding capacity more than the caseinate. Addition of SCaCN resulted in a coarse, smooth, and more compact protein network; however, WPC gave finer and bunched structures in the scanning electron microscopy micrographs. The use of SCaCN decreased texture scores in probiotic yogurt; probably due to the lower water-holding capacity and higher syneresis values in the caseinate-added yogurt sample. Therefore, the textural characteristics of probiotic yogurts improved depending on the ingredient variety. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Fabrication of large diameter alumino-silicate K+ sources

International Nuclear Information System (INIS)

Baca, D.; Chacon-Golcher, E.; Kwan, J.W.; Wu, J.K.

2003-01-01

Alumino-silicate K + sources have been used in HIF experiments for many years. For example the Neutralized Transport Expt. (NTX) and the High Current Transport Expt. (HCX) are now using this type of ion source with diameters of 2.54 cm and 10 cm respectively. These sources have demonstrated ion currents of 80 mA and 700 mA, for typical HIF pulse lengths of 5-10 (micro)s. The corresponding current density is ∼ 10-15 mA/cm 2 , but much higher current density has been observed using smaller size sources. Recently we have improved our fabrication techniques and, therefore, are able to reliably produce large diameter ion sources with high quality emitter surface without defects. This note provides a detailed description of the procedures employed in the fabrication process. The variables in the processing steps affecting surface quality, such as substrate porosity, powder size distribution, coating technique on large area concave surfaces, drying, and heat firing temperature have been investigated

MoO3 incorporation in magnesium aluminosilicate glasses

International Nuclear Information System (INIS)

Tan, Shengheng; Ojovan, Michael I.; Hyatt, Neil C.; Hand, Russell J.

2015-01-01

Molybdate has a very low solubility in silicate and borosilicate glass systems and its excess presence in nuclear waste glass can cause the formation of a readily soluble “yellow phase”. In this study, the incorporation of molybdenum oxide (MoO 3 ) in a magnesium aluminosilicate glass system has been investigated. The prepared glasses show a higher than 90% molybdenum retention rate and up to 5.34 mol% (12.28 wt%) MoO 3 can be incorporated into these glasses without causing visible phase separation. The incorporation of MoO 3 increases glass density, decreases glass transition and crystallisation temperatures and intensifies Raman bands assigned to vibrations of MoO 4 2− units. When excess molybdate is added liquid–liquid phase separation and crystallisation occurs. The separated phase is spherical, 200–400 nm in diameter and randomly dispersed. Based on powder X-ray diffraction, Raman spectroscopy and transmission electron microscopy, the separated phase is identified as MgMoO 4

Effect of immobilization on urine calcium excretion in orthopedic patients with pelvic fracture treated by skin traction.

Science.gov (United States)

Derakhshan, Ali; Derakhshan, Nima; Namazi, Hamid; Ghaffarpasand, Fariborz

2015-03-31

To determine the effects on urine calcium excretion of immobilization by skin traction in patients with pelvic fracture. In a prospective study, a consecutive series of patients with pelvic fracture treated by skin traction were enrolled. Serum (calcium, phosphorous, alkaline phosphatase, sodium, potassium, uric acid, BUN, creatinine) and fasting urine calcium, creatinine, sodium, potassium and uric acid were checked within 48 hours of hospitalization and at 7, 14 and 21 days of immobilization and then after 3 months of mobilization. Trends in changes of variables were recorded. Fifty five patients were enrolled in this study; they were 45 (81.8%) males and 10 (18.2%) females with a mean age 19.4 ± 12.7 years. We found that serum levels of calcium (p = 0.004), phosphorous (p = 0.047) and alkaline phosphatase (p = 0.001) increased significantly during the 3 weeks of immobilization. In the same way, urine calcium/ urine creatinine ratio increased significantly in the study period (p = 0.004). No symptomatic renal stone formation was observed during the study period. Immobilization even in short term causes hypercalciuria in orthopedic patients. Although it is transient and improves with subsequent mobilization, it is needed to be considered specifically by the team caring for this group of patients.

Mineral contents and their solubility on calcium carbonat calcite nanocrystals from cockle shell powder (Anadara granosa Linn)

Science.gov (United States)

Widyastuti, S.; Pramushinta, I. A.

2018-03-01

Prepared and characterized calcium carbonat calcite nanocrystals improves solubility. Calcium carbonat calcite nanocrystals were synthesized using precipitation method from the waste of blood clam cockle shells (Anadara granosa Linn). This study was conducted to analyze mineral composition of nanocrystals calcium carbonat calcite cockle (Anadara granosa) shell for calcium fortification of food applications and to evaluate the solubilities of Calsium and Phospor. The sample of nanocrystals from cockle shells was evaluated to determine the content of 11 macro-and micro-elements. These elements are Calcium (Ca), Magnesium (Mg), Sodium (Na), Phosphorus (P), Potassium (K), Ferrum (Fe), Copper (Cu), Nickel (Ni), Zink (Zn), Boron (B) and Silica (Si)). Cockleshell powders were found to contain toxic elements below detectable levels. The solubilities of Calcium and Phospor were p<0.05.

Thermal properties and modeling of aluminosilicate materials for low-temperature bulk applications

International Nuclear Information System (INIS)

Kaushal, S.

1988-01-01

This thesis concerns itself with the thermal properties of aluminosilicate materials such as cements, blended cements and clays and their application to the problem of radioactive waste encapsulation. The objective of this thesis is to study the thermal properties (heat of hydration, thermal conductivity and diffusivity) of these materials and to determine their effect on the temperature in large monoliths and on the material itself. In this thesis the hydration temperatures for the extreme conditions (adiabatic) were experimentally measured and compared to those predicted under real conditions. Such a simulation can be made by measuring the thermal properties and studying the temperature distribution predicted by a finite differences computer model. Measurements of adiabatic temperature rise were made using a computer-controlled adiabatic calorimeter which was designed and developed for this thesis. Conditions very close to zero heat exchange with the environment were achieved. The existence of this method made it possible to actually observe the fact that cement hydration results in boiling off of the water in such conditions. A number of additives were tried to prevent this. It was observed that waste or by-product materials such as blast furnace slag and fly ash could be used to dramatically reduced the temperature in large bodies. These materials also reacted extensively with the highly alkaline radioactive waste solution to form hydrogarnet and zeolitic material which had useful cementing properties. The conclusion was reached that a selection of blends of aluminosilicate materials can be utilized for providing the proper thermal environment for long-term geological disposal of radioactive waste

The calcium-paracaseinate-phosphate-complex under conditions similar to those in cheese

NARCIS (Netherlands)

Monib, A.M.M.F.

1962-01-01

The complex of calcium-paracaseinate-phosphate is the matrix substance of cheese. The changes it undergoes during maturing determines many characteristics of the finished product.

The preliminary studies of the effect of pH and sodium chloride on the swelling and solubility of the

Process for controlling calcium in a leach operation

International Nuclear Information System (INIS)

Habib, E.J.

1982-01-01

A method for controlling calcium, e.g. calcite, build-up in the leach solution of a uranium and/or related values recovery operation wherein the leach solution is flowed through a value bearing ore to dissolve the desired values. A soluble fluoride, e.g. sodium fluoride, is added to the leach solution after it has passed through the ore to thereby precipitate calcium fluoride from the leach solution and lower the calcium content of the leach solution. The soluble fluoride may be added to the leach solution before the leach solution passes through the process equipment which is used to remove the values from the leach solution or the soluble fluoride may be added after the leach solution passes through the process equipment. If added before, it is preferable to also add a carbonate/bicarbonate solution along with the soluble fluoride to prevent coprecipitation of uranyl/desired value fluoride or to redissolve coprecipitated fluoride back into the leach solution

Oxygen and sodium plasma-implanted nickel-titanium shape memory alloy: A novel method to promote hydroxyapatite formation and suppress nickel leaching

International Nuclear Information System (INIS)

Chan, Y.L.; Yeung, K.W.K.; Lu, W.W.; Ngan, A.H.W.; Luk, K.D.K.; Chan, D.; Wu, S.L.; Liu, X.M.; Chu, Paul K.; Cheung, K.M.C.

2007-01-01

This study aims at modifying the surface bioactivity of NiTi by sodium and oxygen plasma immersion ion implantation (PIII). Sodium ions were implanted into oxygen plasma-implanted NiTi and untreated NiTi. X-ray photoelectron spectroscopy (XPS) revealed that more sodium was implanted into the oxygen pre-implanted sample in comparison with the untreated surface. Scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX) detected calcium and phosphorus rich deposits on both samples after immersion in simulated body fluids for 7 and 21 days. Inductively-coupled plasma mass spectrometry (ICPMS) conducted on the deposits dissolved in diluted hydrochloric acid showed more calcium on the oxygen PIII samples. The improved corrosion resistance of the oxygen PIII NiTi was retained after sodium PIII as evaluated by potentiodynamic polarization tests. Better spreading and proliferation of osteoblasts were also observed on the treated samples

The use of natural and industrial aluminosilicates in the process of adsorption of heavy metals ions

OpenAIRE

Tsvetkova, A.; Akayev, O.

2010-01-01

The analysis of periodic scientific publications and patent literature was made, in which the possibilities of using natural and industrial silicon-containing compounds as adsorbents of ions of heavy metals are generalized. The conditions of adsorption, as well as the numerical values of the adsorption capacity of the studied materials are described Key words: adsorption, natural and industrial aluminosilicates, heavy metals ions.

Effect of Fluoride, Casein Phosphopeptide–Amorphous Calcium Phosphate and Casein Phosphopeptide–Amorphous Calcium Phosphate Fluoride on Enamel Surface Microhardness After Microabrasion: An In Vitro Study

Directory of Open Access Journals (Sweden)

Ghazaleh Ahmadi Zenouz

2016-03-01

Full Text Available Objectives: This study aimed to assess the effect of applying casein phosphopeptide–amorphous calcium phosphate (CPP-ACP paste, casein phosphopeptide–amorphous calcium phosphate fluoride (CPP-ACPF paste and sodium fluoride gel on surface microhardness of enamel after microabrasion.Materials and Methods: Thirty freshly extracted human premolars were selected. All samples were subjected to hardness indentations made with the Vickers hardness machine and the average value was recorded as the initial surface microhardness. The specimens were then randomly divided into three groups (n=10 of CPP-ACPF, fluoride and CPP-ACP. The teeth were micro-abraded with Opalustre. Microhardness test was performed to assess the post-abrasion hardness. Three remineralization modalities were performed on samples of each group. The enamel surface microhardness measurements were performed. To compare the difference between groups, the rehardening and softening values were defined. One-way ANOVA and Tukey’s post hoc test at a significance level of 5% were used for statistical analysis.Results: The mean microhardness value (MMV had a significant decrease after microabrasion from baseline. The MMV had a significant increase after remineralization in all groups. The MMV of CPP-ACPF group was significantly more than that of fluoride group (P=0.027. The rehardening value of fluoride group was significantly more than that of other groups (P<0.001.Conclusion: All the remineralizing agents were effective for rehardening the enamel after microabrasion. The CPP-ACP and CPP-ACPF pastes are effective, but to a lesser extent than neutral sodium fluoride gel in remineralizing enamel surface. Incorporation of fluoride to CPP-ACP formulation does not provide any additional remineralizing potential.Keywords: Casein phosphopeptide-amorphous calcium phosphate nanocomplex; Enamel Microabrasion; Hardness; Sodium Fluoride

Evidence of calcium carbonates in coastal (Talos Dome and Ross Sea area) East Antarctica snow and firn: Environmental and climatic implications

Science.gov (United States)

Sala, M.; Delmonte, B.; Frezzotti, M.; Proposito, M.; Scarchilli, C.; Maggi, V.; Artioli, G.; Dapiaggi, M.; Marino, F.; Ricci, P. C.; De Giudici, G.

2008-07-01

Micrometre-sized aeolian dust particles stored in Antarctic firn and ice layers are a useful tool for reconstructing climate and environmental changes in the past. The mineral content, particle concentration and chemical composition of modern dust in firn cores from the peripherycal dome (Talos Dome) and coastal area of East Antarctica (Ross Sea sector) were investigated. During analyses there was a considerable decrease in microparticle concentrations within a few hours of ice sample melting, accompanied by a systematic increase in the concentration of calcium ions (Ca 2+) in solution. Based on mineralogical phase analyses, which reveal the presence of anhydrous and hydrous calcium carbonates such as calcite (CaCO 3), monohydrocalcite (CaCO 3·H 2O) and ikaite (CaCO 3·6H 2O, hexahydrate calcium carbonate), the observed variations in concentrations are ascribed to the partial dissolution of the carbonate content of samples. Soluble carbonate compounds are thus primary aerosols included into the samples along with insoluble aluminosilicate minerals. We hypothesize hydrous carbonates may derive from the sea ice surface, where ikaite typically forms at the early stages of sea ice formation. Back trajectory calculations show that favourable events for air mass advection from the sea ice surface to Talos Dome are rare but likely to occur.

Oxygen titration in sodium. The mercury method and its use for very low values

International Nuclear Information System (INIS)

Champeix, L.; Darras, R.; Duflo, J.

1958-01-01

The mercury method for the oxygen titration in sodium has now been known for ten years and is probably the more frequently used. In this text, precision are given to what extent it is valuable when used in microanalysis. Details are given on the apparatus, its manipulation and its calibration. After testing, we have decided to use flame spectroscopy to titrate the sodium hydroxide formed. Discussions are exposed on the errors due to the presence of sodium chloride and calcium. Results are examined from the point of view of their reproducibility and accuracy. If great care is taken, this method allows oxygen titration in sodium even for values below 10 ppm with satisfactory precision. (author) [fr

An increase in [Ca2+]i activates basolateral chloride channels and inhibits apical sodium channels in frog skin epithelium

DEFF Research Database (Denmark)

Brodin, Birger; Rytved, K A; Nielsen, R

1996-01-01

The aim of this study was to investigate the mechanisms by which increases in free cytosolic calcium ([Ca2+]i) cause a decrease in macroscopic sodium absorption across principal cells of the frog skin epithelium. [Ca2+]i was measured with fura-2 in an epifluorescence microscope set-up, sodium abs...

Calcium ion binding to a soil fulvic acid using a Donnan Potential model

International Nuclear Information System (INIS)

Marinsky, J.A.

1999-01-01

Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 x 10 -4 moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log β app ) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log β app =2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential correction term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log β=1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. (orig.)

Calcium-independent phospholipase A₂, group VIA, is critical for RPE cell survival

DEFF Research Database (Denmark)

Kolko, Miriam; Vohra, Rupali; Westlund, Barbro S.

2014-01-01

PURPOSE: To investigate the significance of calcium-independent phospholipase A₂, group VIA (iPLA2-VIA), in RPE cell survival following responses to sodium iodate (SI) in cell cultures. METHODS: The human retinal pigment epithelium (RPE) cell line (ARPE-19) cells and primary mouse-RPE cultures were...

Tumorigenicity of sodium ascorbate in male rats.

Science.gov (United States)

Cohen, S M; Anderson, T A; de Oliveira, L M; Arnold, L L

1998-06-15

Sodium ascorbate, like other sodium salts such as saccharin, glutamate, and bicarbonate, produces urinary alterations when fed at high doses to rats, which results in mild superficial urothelial cytotoxicity and regeneration but not tumors in a standard 2-year bioassay. Sodium saccharin was shown to produce a low incidence of bladder tumors in rats if administered in a two-generation bioassay. In the present study, we evaluated sodium ascorbate in a two-generation bioassay that involved feeding to the male and female parental F344 rats for 4 weeks before mating, feeding the dams during gestation and lactation, and then feeding the weaned (at 28 days of age) male F1 generation rats for the remainder of their lifetime (up to 128 weeks of the experiment). Dietary levels of 1.0, 5.0, and 7.0% sodium ascorbate were tested. At 5.0 and 7.0% sodium ascorbate, there was an increase in urinary bladder urothelial papillary and nodular hyperplasia and the induction of a few papillomas and carcinomas. There was a dose-responsive increase in renal pelvic calcification and hyperplasia and inhibition of the aging nephropathy of rats even at the level of 1% sodium ascorbate. Because the short-term urothelial effects of sodium ascorbate in rats are inhibited by treatments producing urinary acidification to pH sodium ascorbate to evaluate the long-term effects. The combination of 7.0% sodium ascorbate plus 2.78% NH4Cl in the diet was toxic, and the group was terminated early during the course of the experiment. The group fed 5.0% sodium ascorbate plus 2.04% NH4Cl showed complete inhibition of the urothelial effects of sodium ascorbate and significant inhibition of its renal effects. We also demonstrated the presence of a calcium phosphate-containing urinary precipitate in rats fed sodium ascorbate at all doses, in a dose-responsive manner. The formation of the precipitate was inhibited by coadministration with NH4Cl. The proliferative effects of sodium ascorbate on the male rat

The plumber's nightmare: a new morphology in block copolymer-ceramic nanocomposites and mesoporous aluminosilicates.

Science.gov (United States)

Finnefrock, Adam C; Ulrich, Ralph; Toombes, Gilman E S; Gruner, Sol M; Wiesner, Ulrich

2003-10-29

A novel cubic bicontinuous morphology is found in polymer-ceramic nanocomposites and mesoporous aluminosilicates that are derived by an amphiphilic diblock copolymer, poly(isoprene-b-ethylene oxide) (PI-b-PEO), used as a structure-directing agent for an inorganic aluminosilicate. Small-angle X-ray scattering (SAXS) was employed to unambiguously identify the Im(-)3m crystallographic symmetry of the materials by fitting individual Bragg peak positions in the two-dimensional X-ray images. Structure factor calculations, in conjunction with results from transmission electron microscopy, were used to narrow the range of possible structures consistent with the symmetry and showed the plumber's nightmare morphology to be consistent with the data. The samples are made by deposition onto a substrate that imposes a strain field, generating a lattice distortion. This distortion is quantitatively analyzed and shown to have resulted in shrinkage of the crystallites by approximately one-third in a direction perpendicular to the substrate, in both as-made composites and calcined ceramic materials. Finally, the observation of the bicontinuous block-copolymer-derived hybrid morphology is discussed in the context of a pseudo-ternary morphology diagram and compared to existing studies of ternary phase diagrams of amphiphiles in a mixture of two solvents. The calcined mesoporous materials have potential applications in the fields of catalysis, separation technology, and microelectronics.

Effects of the Addition of Sodium Alginate and the Concentration of Calcium Chloride on the Properties of Composite Nonwoven Fabrics

Directory of Open Access Journals (Sweden)

Lou Ching-Wen

2016-01-01

Full Text Available Nonwoven fabrics have merits, and for example, they can be simply and quickly processed with a variety of materials and an easily changeable manufacturing process. This study aims to examine the influences of the addition of sodium alginate (SA and the concentration of calcium chloride (CaCl2 on the properties of the composite nonwoven fabrics. Chitosan (CS micro-particles and SA solution are cross-linked with CaCl2 with various concentrations, combined with farir heat preservative staples (FT/cotton (C nonwoven fabrics, and then freeze-dried to form CS/SA/FT/C composite nonwoven fabrics. Afterwards, physical property tests are performed on the resulting composite nonwoven fabrics to determine their properties as related to various concentrations of CaCl2. The addition of SA decreases the water vapor permeability of FT/C nonwoven fabrics by 15 %, but the concentrations of CaCl2 do not influence the water vapor permeability. Compared to FT/C nonwoven fabrics, CS/SA/FT/C composite nonwoven fabrics have significantly lower water absorbency and water vapor permeability, but a greater stiffness.

Assessment of the multi-mycotoxin-binding efficacy of a carbon/aluminosilicate-based product in an in vitro gastrointestinal model

NARCIS (Netherlands)

Avantaggiato, G.; Havenaar, R.; Visconti, A.

2007-01-01

A laboratory model, set to simulate the in vivo conditions of the porcine gastrointestinal tract, was used to study the small intestinal absorption of several mycotoxins and the effectiveness of Standard Q/FIS (a carbon/aluminosilicate-based product) in reducing mycotoxin absorption when added to

Effects of Sodium Hydroxide and Sodium Aluminate on the Precipitation of Aluminum Containing Species in Tank Wastes

International Nuclear Information System (INIS)

Mattigod, Shas V.; Hobbs, David T.; Parker, Kent E.; McCready, David E.; Wang, Li Q.

2006-01-01

Aluminisilicate deposit buildup experienced during the tank waste volume-reduction process at the Savannah River Site (SRS) required an evaporator to be shut down. Studies were conducted at 80 C to identify the insoluble aluminosilicate phase(s) and to determine the kinetics of their formation and transformation. These tests were carried out under conditions more similar to those that occur in HLW tanks and evaporators. Comparison of our results with those reported from the site show very similar trends. Initially, an amorphous phase precipitates followed by a zeolite phase that transforms to sodalite and which finally converts to cancrinite. Our results also show the expected trend of an increased rate of transformation into denser aluminosilicate phases (sodalite and cancrinite) with time and increasing hydroxide concentrations

Polyelectrolyte addition effect on the properties of setting hydraulic cements based on calcium phosphate

International Nuclear Information System (INIS)

Santos, Luis A. dos; Oliveira, Luci C. de; Rigo, Eliana C.S.; Boschi, Anselmo Ortega; Carrodeguas, Raul Gracia

1997-01-01

In the present work the effects of the addition of some poly electrolytes (sodium alginate and poly acrylic acid) on the solubility, crystalline phases, pH and mechanical strength under compression of three calcium phosphate cements were studied. (author)

The influence of carbon source and calcium on the production of ...

African Journals Online (AJOL)

E. chrysanthemi targets the host's middle lamella, which was mainly made of pectic substances containing calcium, for colonization. In this study, it is reported that a pectic substance, such as sodium polypectate (NaPP) may be preferable, not only for the production of hydrolytic enzymes, but for the production of protease as ...

Evaluation of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to repair acid-softened enamel using an intra-oral remineralization model.

Science.gov (United States)

Sullivan, R; Rege, A; Corby, P; Klaczany, G; Allen, K; Hershkowitz, D; Goldder, B; Wolff, M

2014-01-01

An intra-oral remineralization study was conducted to compare the ability of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP) to remineralize acid-softened bovine enamel specimens compared to a silica-based dentifrice with 1450 ppm fluoride as MFP. The intra-oral clinical study employed a double blind, two-treatment, crossover design, and used an upper palatal retainer to expose the enamel specimens to the oral environment during product use and periods of remineralization. The retainer was designed to house three partially demineralized bovine enamel samples. The study population was comprised of 30 adults, ages 18 to 70 years. The study consisted of two treatment phases with a washout period lasting seven (+/- three) days preceding each treatment phase. A silica-based dentifrice without fluoride was used during the washout period. The Test Dentifrice used in this study contained 8% arginine, calcium carbonate, and 1450 ppm fluoride as sodium monofluorophosphate (MFP). The Control Dentifrice was silica-based and contained 1450 ppm fluoride as MFP. The treatment period consisted of a three-day lead-in period with the assigned product. The panelists brushed two times per day during the three-day lead-in period with the assigned product. On the fourth day, the panelists began brushing with the assigned product with the retainer in their mouth. The panelists brushed for one minute, followed by a one-minute swish with the slurry and a rinse with 15 ml of water in the morning, in the afternoon, and night with the retainer in the mouth. The panelists brushed only their teeth and not the specimens directly. Changes in mineral content before and after treatment were measured using a Knoop microhardness tester. The results of the study showed that percent remineralization values for the Test Dentifrice and Control Dentifrice were 14.99% and 8.66%, respectively. A statistical analysis

Functional Effects of Prebiotic Fructans in Colon Cancer and Calcium Metabolism in Animal Models

OpenAIRE

Rivera-Huerta, Marisol; Liz?rraga-Grimes, Vania Lorena; Castro-Torres, Ibrahim Guillermo; Tinoco-M?ndez, Mabel; Mac?as-Rosales, Luc?a; S?nchez-Bart?z, Francisco; Tapia-P?rez, Graciela Guadalupe; Romero-Romero, Laura; Gracia-Mora, Mar?a Isabel

2017-01-01

Inulin-type fructans are polymers of fructose molecules and are known for their capacity to enhance absorption of calcium and magnesium, to modulate gut microbiota and energy metabolism, and to improve glycemia. We evaluated and compared the effects of Chicory inulin “Synergy 1®” and inulin from Mexican agave “Metlin®” in two experimental models of colon cancer and bone calcium metabolism in mice and rats. Inulins inhibited the development of dextran sulfate sodium-induced colitis and colon c...

Inhibition of crystallization of calcium oxalate by the extraction of Tamarix gallica L.

Science.gov (United States)

Bensatal, Ahmed; Ouahrani, M R

2008-12-01

The main objective is to study the inhibitor effect of acid fraction of the extract of Tamarix gallica L on the crystallization of calcium oxalate. The extract of Tamarix gallica L is very rich by acid compounds that are used as an inhibitor of nephrolithiasis (calcium oxalate). Our study of the calcium oxalate crystallization is based on the model of turbidimetry by means of a spectrophotometer. The calcium oxalate formation is induced by the addition of oxalate solutions of sodium and of calcium chloride. The addition of inhibitor with various concentrations enabled us to give information on the percentage of inhibition. The comparison between the turbidimetric slopes with and without inhibitor gives the effectiveness of inhibitor for the acid fraction. By comparing the photographs of with and without inhibitor, we concluded that the extract of Tamarix gallica L acts at the stage of growth. The acid fraction of the extract of Tamarix gallica L gives an activity remarkable in the formation of urinary lithiasis (calcium oxalate); this effectiveness is due to the presence of functions of acid.

Preparation and characterization of coating sodium trisilicate (Na2O.nSiO2) at calcium carbonate (CaCO3) for blowing agent in Mg alloy foam

Science.gov (United States)

Erryani, Aprilia; Lestari, Franciska Pramuji; Annur, Dhyah; Kartika, Ika

2018-05-01

The role of blowing agent in the manufacture of porous metal alloys is very important to produce the desired pore. The thermal stability and speed of foam formation have an effect on the resulting pore structure. In porous metal alloys, uniformity of size and pore deployment are the main determinants of the resulting alloys. The coating process of calcium carbonate (CaCO3) has been done using Sodium trisilicate solution by sol-gel method. Foaming agent was pretreated by coating SiO2 passive layer on the surface of CaCO3. This coating aims to produce a more stable blowing agent so that the foaming process can produce a more uniform pore size. The microstructure of the SiO2 passive was observed using Scanning Electron Microscope (SEM) equipped by Energy Dispersive X-Ray Spectrometer (EDS) mapping. The results showed coating CaCO3 using sodium trisilicate was successfully done creating a passive layer of SiO2 on the surface of CaCO3. By the coating process, the thermal stability of coated CaCO3 increased compared to uncoated CaCO3.

Canadian Initiatives to Prevent Hypertension by Reducing Dietary Sodium

Science.gov (United States)

Campbell, Norm R. C.; Willis, Kevin J.; L’Abbe, Mary; Strang, Robert; Young, Eric

2011-01-01

Hypertension is the leading risk for premature death in the world. High dietary sodium is an important contributor to increased blood pressure and is strongly associated with other important diseases (e.g., gastric cancer, calcium containing kidney stones, osteoporosis, asthma and obesity). The average dietary sodium intake in Canada is approximately 3400 mg/day. It is estimated that 30% of hypertension, more than 10% of cardiovascular events and 1.4 billion dollars/year in health care expenses are caused by this high level of intake in Canada. Since 2006, Canada has had a focused and evolving effort to reduce dietary sodium based on actions from Non Governmental Organizations (NGO), and Federal and Provincial/Territorial Government actions. NGOs initiated Canadian sodium reduction programs by developing a policy statement outlining the health issue and calling for governmental, NGO and industry action, developing and disseminating an extensive health care professional education program including resources for patient education, developing a public awareness campaign through extensive media releases and publications in the lay press. The Federal Government responded by striking a Intersectoral Sodium Work Group to develop recommendations on how to implement Canada’s dietary reference intake values for dietary sodium and by developing timelines and targets for foods to be reduced in sodium, assessing key research gaps with funding for targeted dietary sodium based research, developing plans for public education and for conducting evaluation of the program to reduce dietary sodium. While food regulation is a Federal Government responsibility Provincial and Territorial governments indicated reducing dietary sodium needed to be a priority. Federal and Provincial Ministers of Health have endorsed a target to reduce the average consumption of sodium to 2300 mg/day by 2016 and the Deputy Ministers of Health have tasked a joint committee to review the recommendations of

Canadian Initiatives to Prevent Hypertension by Reducing Dietary Sodium

Directory of Open Access Journals (Sweden)

Robert Strang

2011-08-01

Full Text Available Hypertension is the leading risk for premature death in the world. High dietary sodium is an important contributor to increased blood pressure and is strongly associated with other important diseases (e.g., gastric cancer, calcium containing kidney stones, osteoporosis, asthma and obesity. The average dietary sodium intake in Canada is approximately 3400 mg/day. It is estimated that 30% of hypertension, more than 10% of cardiovascular events and 1.4 billion dollars/year in health care expenses are caused by this high level of intake in Canada. Since 2006, Canada has had a focused and evolving effort to reduce dietary sodium based on actions from Non Governmental Organizations (NGO, and Federal and Provincial/Territorial Government actions. NGOs initiated Canadian sodium reduction programs by developing a policy statement outlining the health issue and calling for governmental, NGO and industry action, developing and disseminating an extensive health care professional education program including resources for patient education, developing a public awareness campaign through extensive media releases and publications in the lay press. The Federal Government responded by striking a Intersectoral Sodium Work Group to develop recommendations on how to implement Canada’s dietary reference intake values for dietary sodium and by developing timelines and targets for foods to be reduced in sodium, assessing key research gaps with funding for targeted dietary sodium based research, developing plans for public education and for conducting evaluation of the program to reduce dietary sodium. While food regulation is a Federal Government responsibility Provincial and Territorial governments indicated reducing dietary sodium needed to be a priority. Federal and Provincial Ministers of Health have endorsed a target to reduce the average consumption of sodium to 2300 mg/day by 2016 and the Deputy Ministers of Health have tasked a joint committee to review the

Calcium extraction from brine water and seawater using oxalic acid

Science.gov (United States)

Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

2017-01-01

Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

Comparative study on the change in index of refraction in ion-exchange interdiffusion in alkali-silicate glasses containing calcium, strontium, barium and titanium oxides

International Nuclear Information System (INIS)

Livshits, V.Ya.; Marchuk, E.A.

1993-01-01

Different ability to ion exchange from the salts of lithium-sodium-silicate glass melt containing calcium (or strontium, or barium) and titanium oxides in addition has been shown. CaO, SrO and BaO have negative effect, but TiO 2 -positive one on the fullness of ion exchange of lithium-sodium and on the rate of interdiffusion in alkali-silicate glass. The value of change in index of refraction of glass with TiO 2 is twice higher than glass with calcium oxide (or strontium, or barium) as the fourth component

Crosslink between calcium and sodium signalling.

Science.gov (United States)

Verkhratsky, Alexei; Trebak, Mohamed; Perocchi, Fabiana; Khananshvili, Daniel; Sekler, Israel

2018-02-01

What is the topic of this review? This paper overviews the links between Ca 2+ and Na + signalling in various types of cells. What advances does it highlight? This paper highlights the general importance of ionic signalling and overviews the molecular mechanisms linking Na + and Ca 2+ dynamics. In particular, the narrative focuses on the molecular physiology of plasmalemmal and mitochondrial Na + -Ca 2+ exchangers and plasmalemmal transient receptor potential channels. Functional consequences of Ca 2+ and Na + signalling for co-ordination of neuronal activity with astroglial homeostatic pathways fundamental for synaptic transmission are discussed. Transmembrane ionic gradients, which are an indispensable feature of life, are used for generation of cytosolic ionic signals that regulate a host of cellular functions. Intracellular signalling mediated by Ca 2+ and Na + is tightly linked through several molecular pathways that generate Ca 2+ and Na + fluxes and are in turn regulated by both ions. Transient receptor potential (TRP) channels bridge endoplasmic reticulum Ca 2+ release with generation of Na + and Ca 2+ currents. The plasmalemmal Na + -Ca 2+ exchanger (NCX) flickers between forward and reverse mode to co-ordinate the influx and efflux of both ions with membrane polarization and cytosolic ion concentrations. The mitochondrial calcium uniporter channel (MCU) and mitochondrial Na + -Ca 2+ exchanger (NCLX) mediate Ca 2+ entry into and release from this organelle and couple cytosolic Ca 2+ and Na + fluctuations with cellular energetics. Cellular Ca 2+ and Na + signalling controls numerous functional responses and, in the CNS, provides for fast regulation of astroglial homeostatic cascades that are crucial for maintenance of synaptic transmission. © 2017 The Authors. Experimental Physiology © 2017 The Physiological Society.

Synergism between sodium chloride, sucrose and tricalcium phosphate in the osmotic dehydration of oca (Oxalis tuberosa with and without chitosan coating

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José Arroyo Portal

2010-12-01

Full Text Available We investigated the synergistic effect of three solutes (sodium chloride, sucrose, tricalcium phosphate in different combinations of concentration, on the moisture, solid gain and calcium gain in oca (Oxalis tuberosa with and without chitosan (CR and SR. In both cases applied the Simplex with Extended Centroid mixture design. Were used cylinders of oca of 0.9 cm of diameter and 3.4 cm of length. The kinetics of moisture, solid gain and calcium gain for 48 hours was evaluated. The effective diffusivity of water, solids and calcium was determined. We found that in samples CR is greater loss of water and less solid gain compared with SR samples mainly as sodium chloride or sucrose participate independently, while for the gain of calcium, in all cases, the CR samples gain more of calcium than SR samples. The effective diffusivities found are: water, 1.19E-09 m2 /s in samples CR and 1.34E-09 m2 /s in SR samples; for solid, 3.67E-09 m2 /s in samples CR and 5.43E-09 m2 /s in SR samples; and, for calcium 3.32E-11 m2 /s in samples CR and 1.57E-09 m2 /s in SR samples.

Sol-gel dip coating of yttria-stabilized tetragonal zirconia dental ceramic by aluminosilicate nanocomposite as a novel technique to improve the bonding of veneering porcelain.

Science.gov (United States)

Madani, Azamsadat; Nakhaei, Mohammadreza; Karami, Parisa; Rajabzadeh, Ghadir; Salehi, Sahar; Bagheri, Hossein

2016-01-01

The aim of this in vitro study was to evaluate the effect of silica and aluminosilicate nanocomposite coating of zirconia-based dental ceramic by a sol-gel dip-coating technique on the bond strength of veneering porcelain to the yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) in vitro. Thirty Y-TZP blocks (10 mm ×10 mm ×3 mm) were prepared and were assigned to four experimental groups (n=10/group): C, without any further surface treatment as the control group; S, sandblasted using 110 μm alumina powder; Si, silica sol dip coating + calcination; and Si/Al, aluminosilicate sol dip coating + calcination. After preparing Y-TZP samples, a 3 mm thick layer of the recommended porcelain was fired on the coated Y-TZP surface. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis were used to characterize the coating and the nature of the bonding between the coating and zirconia. To examine the zirconia-porcelain bond strength, a microtensile bond strength (μTBS) approach was chosen. FT-IR study showed the formation of silica and aluminosilicate materials. XRD pattern showed the formation of new phases consisting of Si, Al, and Zr in coated samples. SEM showed the formation of a uniform coating on Y-TZP samples. Maximum μTBS values were obtained in aluminosilicate samples, which were significantly increased compared to control and sandblasted groups (P=0.013 and Pcoating can be considered as a convenient, less expensive reliable method for improving the bond strength between dental Y-TZP ceramics and veneering porcelain.

Calcium aluminates hydration in presence of amorphous SiO2 at temperatures below 90 deg. C

International Nuclear Information System (INIS)

Rivas Mercury, J.M.; Turrillas, X.; Aza, A.H. de; Pena, P.

2006-01-01

The hydration behaviour of Ca 3 Al 2 O 6 , Ca 12 Al 14 O 33 and CaAl 2 O 4 with added amorphous silica at 40, 65 and 90 deg. C has been studied for periods ranging from 1 to 31 days. In hydrated samples crystalline phases like katoite (Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x ) and gibbsite, Al(OH) 3 , were identified, likewise amorphous phases like Al(OH) x , calcium silicate hydrates, C-S-H, and calcium aluminosilicate hydrates, C-S-A-H, were identified. The stoichiometry of Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x (0≤3-x≤0.334), which was the main crystalline product, was established by Rietveld refinement of X-ray and neutron diffraction data and by transmission electron microscopy. - Graphical abstract: Katoite, Ca 3 Al 2 (SiO 4 ) 3- x (OH) 4 x (0≤3-x≤0.334), was identified besides gibbsite, Al(OH) 3 , as a crystalline stable hydration products in Ca 3 Al 2 O 6 , Ca 12 Al 14 O 33 and CaAl 2 O 4 hydrated with added amorphous silica between 40 and 90 deg. C

Simultaneous mapping of membrane voltage and calcium in zebrafish heart in vivo reveals chamber-specific developmental transitions in ionic currents

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Jennifer H Hou

2014-09-01

Full Text Available The cardiac action potential (AP and the consequent cytosolic Ca2+ transient are key indicators of cardiac function. Natural developmental processes, as well as many drugs and pathologies change the waveform, propagation, or variability (between cells or over time of these parameters. Here we apply a genetically encoded dual-function calcium and voltage reporter (CaViar to study the development of the zebrafish heart in vivo between 1.5 and 4 days post fertilization (dpf. We developed a high-sensitivity spinning disk confocal microscope and associated software for simultaneous three-dimensional optical mapping of voltage and calcium. We produced a transgenic zebrafish line expressing CaViar under control of the heart-specific cmlc2 promoter, and applied ion channel blockers at a series of developmental stages to map the maturation of the action potential in vivo. Early in development, the AP initiated via a calcium current through L-type calcium channels. Between 90 – 102 hours post fertilization (hpf, the ventricular AP switched to a sodium-driven upswing, while the atrial AP remained calcium driven. In the adult zebrafish heart, a sodium current drives the AP in both the atrium and ventricle. Simultaneous voltage and calcium imaging with genetically encoded reporters provides a new approach for monitoring cardiac development, and the effects of drugs on cardiac function.

Calcium carbonate synthesis with prescribed properties based on liquid waste of soda production

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E.O. Mikhailova

2016-09-01

Full Text Available A promising direction in solving of environmental problems of soda industry is the development of low-waste resource-saving technologies, which consist in recycling of valuable waste components with obtaining the commercial products. Aim: The aim is to establish the optimal conditions for obtaining calcium carbonate with prescribed properties from liquid waste of soda production. Materials and Methods: Chemically deposited calcium carbonate is used as filler and should have certain physical and chemical properties. To obtain a product of prescribed quality the process of calcium carbonate deposition was performed of still waste liquid, that is the waste of calcium carbonate production and contain significant amount of calcium ions, and excessive production of the purified stock solution of sodium bicarbonate, which is composed of carbonate and hydrocarbonate ions. Results: The dependence of bulk density and specific surface area of calcium carbonate sediments and degree of deposition from such technological parameters are established: method of mixing the stock solutions, the concentration and molar ratio of reactants, temperature and reaction time. Conclusions: The optimal mode of deposition process is determined and the concept of production of calcium carbonate is developed. The quality of calcium carbonate meets the modern requirements of high dispersion, low bulk density and evolved specific surface of the product.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

Science.gov (United States)

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

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

Science.gov (United States)

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+ ...

Influence of calcium on ceramide-1-phosphate monolayers

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Joana S. L. Oliveira

2016-02-01

Full Text Available Ceramide-1-phosphate (C1P plays an important role in several biological processes, being identified as a key regulator of many protein functions. For instance, it acts as a mediator of inflammatory responses. The mediation of the inflammation process happens due to the interaction of C1P with the C2 domain of cPLA2α, an effector protein that needs the presence of submicromolar concentrations of calcium ions. The aim of this study was to determine the phase behaviour and structural properties of C1P in the presence and absence of millimolar quantities of calcium in a well-defined pH environment. For that purpose, we used monomolecular films of C1P at the soft air/liquid interface with calcium ions in the subphase. The pH was varied to change the protonation degree of the C1P head group. We used surface pressure versus molecular area isotherms coupled with other monolayer techniques as Brewster angle microscopy (BAM, infrared reflection–absorption spectroscopy (IRRAS and grazing incidence X-ray diffraction (GIXD. The isotherms indicate that C1P monolayers are in a condensed state in the presence of calcium ions, regardless of the pH. At higher pH without calcium ions, the monolayer is in a liquid-expanded state due to repulsion between the negatively charged phosphate groups of the C1P molecules. When divalent calcium ions are added, they are able to bridge the highly charged phosphate groups, enhancing the regular arrangement of the head groups. Similar solidification of the monolayer structure can be seen in the presence of a 150 times larger concentration of monovalent sodium ions. Therefore, calcium ions have clearly a strong affinity for the phosphomonoester of C1P.

Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

Energy Technology Data Exchange (ETDEWEB)

Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim, E-mail: joachimloo@ntu.edu.sg [Nanyang Technological University, School of Materials Science and Engineering (Singapore)

2012-06-15

Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

Designing calcium phosphate-based bifunctional nanocapsules with bone-targeting properties

International Nuclear Information System (INIS)

Khung, Yit-Lung; Bastari, Kelsen; Cho, Xing Ling; Yee, Wu Aik; Loo, Say Chye Joachim

2012-01-01

Using sodium dodecyl sulphate micelles as template, hollow-cored calcium phosphate nanocapsules were produced. The surfaces of the nanocapsule were subsequently silanised by a polyethylene glycol (PEG)-based silane with an N-hydroxysuccinimide ester end groups which permits for further attachment with bisphosphonates (BP). Characterisations of these nanocapsules were investigated using Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy, Fourier Transform Infra-Red Spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Dynamic Light Scattering. To further validate the bone-targeting potential, dentine discs were incubated with these functionalised nanocapsules. FESEM analysis showed that these surface-modified nanocapsules would bind strongly to dentine surfaces compared to non-functionalised nanocapsules. We envisage that respective components would give this construct a bifunctional attribute, whereby (1) the shell of the calcium phosphate nanocapsule would serve as biocompatible coating aiding in gradual osteoconduction, while (2) surface BP moieties, acting as targeting ligands, would provide the bone-targeting potential of these calcium phosphate nanocapsules.

Direct reading spectrochemical analysis of sodium uranate

International Nuclear Information System (INIS)

Roca, M.; Capdevila, C.

1966-01-01

We describe the application of the quantometer to the analysis of sodium uranate. To determine boron, cadmium, phosphorus and molybdenum contents, the samples are mixed with graphite powder (1:30) and excited in a 10 amperes direct current arc with 4x4,,5 mm cup graphite rods, using silver as internal standard. A not se deep cup and a dilution factor of 90 are more suitable for calcium, copper, iron, silicon and vanadium determination; cobalt and chromium are the internal standards. (Author) 6 refs

A novel method to produce dry geopolymer cement powder

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H.A. Abdel-Gawwad

2016-04-01

Full Text Available Geopolymer cement is the result of reaction of two materials containing aluminosilicate and concentrated alkaline solution to produce an inorganic polymer binder. The alkali solutions are corrosive and often viscous solutions which are not user friendly, and would be difficult to use for bulk production. This work aims to produce one-mix geopolymer mixed water that could be an alternative to Portland cement by blending with dry activator. Sodium hydroxide (SH was dissolved in water and added to calcium carbonate (CC then dried at 80 °C for 8 h followed by pulverization to a fixed particle size to produce the dry activator consisting of calcium hydroxide (CH, sodium carbonate (SC and pirssonite (P. This increases their commercial availability. The dry activator was blended with granulated blast-furnace slag (GBFS to produce geopolymer cement powder and by addition of water; the geopolymerization process is started. The effect of W/C and SH/CC ratio on the physico-mechanical properties of slag pastes was studied. The results showed that the optimum percent of activator and CC content is 4% SH and 5% CC, by the weight of slag, which give the highest physico-mechanical properties of GBFS. The characterization of the activated slag pastes was carried out using TGA, DTG, IR spectroscopy and SEM techniques.

Colonic necrosis due to calcium polystyrene sulfonate (Kalimate not suspended in sorbitol

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María Dolores Castillo-Cejas

2013-04-01

Full Text Available Cation-exchange resins are used in the management of hyperkalemia, particularly in patients with end-stage renal disease. These resins were associated with gastrointestinal tract lesions, especially sodium polystyrene sulfonate (Kayexalate mixed with sorbitol. We present a case of colonic necrosis after the administration of calcium polystyrene sulfonate (Kalimate not suspended in sorbitol.

Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

Energy Technology Data Exchange (ETDEWEB)

Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

2015-06-01

Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

Socioeconomic status and intake of energy and sodium are associated with calcium intake among pregnant women in Rafsanjan city, Iran.

Science.gov (United States)

Ebrahimi, Fatemeh; Shariff, Zalilah Mohd; Rezaeian, Mohsen; Tabatabaei, Seyed Zia; Mun, Chan Yoke; Tajik, Esra

2013-01-01

Calcium intake in developing countries is lower than that in developed countries. In Iran, inadequate calcium intake in the general population, especially among women, is a public health concern. This cross-sectional study examined the correlation between sociodemographic, obstetrical and lifestyle factors with calcium intake among pregnant women in Rafsanjan city, southeast Iran. A sample of 308 healthy pregnant women aged 18-35 years from seven urban health-care centers participated in the study. All women were measured for height and weight and interviewed for demographic and socioeconomic, obstetrical, lifestyle and dietary intake information while pre-pregnancy weight was obtained from prenatal record. Stepwise multiple regression was used to assess factors associated with calcium intake. The mean daily calcium intake of women was 968.51±363.05mg/day and only 46.4% of the pregnant women met the dietary reference intakes of 1000 mg for calcium. Milk and milk products showed the greatest contribution to calcium intake (75.11%). Energy-adjusted calcium intake was positively associated with years of schooling (Psodium (P<0.01) intakes. This information would be useful in planning and developing appropriate strategies to improve calcium intake in pregnant women. Efforts to increase calcium intake in pregnant women should focus on promoting nutrient-dense food and making these foods available and accessible, particularly to socioeconomically deprived women. © 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.

Crystallization, Microstructure, and Viscosity Evolutions in Lithium Aluminosilicate Glass-Ceramics

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Qiang Fu

2016-11-01

Full Text Available Lithium aluminosilicate glass-ceramics have found widespread commercial success in areas such as consumer products, telescope mirrors, fireplace windows, etc. However, there is still much to learn regarding the fundamental mechanisms of crystallization, especially related to the evolution of viscosity as a function of the crystallization (ceramming process. In this study, the impact of phase assemblage and microstructure on the viscosity was investigated using high temperature X-ray diffraction (HTXRD, beam bending viscometry (BBV, and transmission electron microscopy (TEM. Results from this study provide a first direct observation of viscosity evolution as a function of ceramming time and temperature. Sharp viscosity increases due to phase separation, nucleation and phase transformation are noticed through BBV measurement. A near-net shape ceramming can be achieved in TiO2-containing compositions by keeping the glass at a high viscosity (> 109 Pa.s throughout the whole thermal treatment.

Method of gradual acid leaching of uranium ores of silicate and aluminosilicate nature

International Nuclear Information System (INIS)

Bosina, B.; Krepelka, J.; Urban, P.; Kropacek, J.; Stransky, J.

1987-01-01

Leaching uranium ore pulp is divided into two stages. The first stage takes place without any addition of a leaching agent at elevated pressure and temperature. In the second stage, sulfuric acid is added to the pulp (50 to 1000 kg per tonne of ore) or an oxidation agent. Leaching then proceeds according to routine procedures. The procedure is used to advantage for silicate or aluminosilicate ores which contain uranium minerals which are difficult to leach, pyrite and reducing substances. The two stage leaching allows to use the technology of pressure leaching, reduces consumption of sulfuric acid and oxidation agents and still achieves the required reduction oxidation potential. (E.S.)

Excessive sodium ions delivered into cells by nanodiamonds: implications for tumor therapy.

Science.gov (United States)

Zhu, Ying; Li, Wenxin; Zhang, Yu; Li, Jing; Liang, Le; Zhang, Xiangzhi; Chen, Nan; Sun, Yanhong; Chen, Wen; Tai, Renzhong; Fan, Chunhai; Huang, Qing

2012-06-11

Nanodiamonds (NDs) possess many excellent physical and chemical properties that make them attractive materials for applications in biomedicine. In this paper, the adsorption and delivery of a large amount of sodium ions into the cell interior by NDs in serum-free medium is demonstrated. The excess sodium ions inside the cells induce osmotic stresses followed by cell swelling and an increase in the intracellular levels of calcium and reactive oxygen species (ROS), which leads to severe cellular damage. In complete culture medium, however, serum proteins wrapped around the NDs effectively prevent the sodium ions from adsorbing onto the NDs, and thus the NDs show no cytotoxicity. This work is the first to elaborate on the correlation between the sodium ions adsorbed on the nanomaterials and their bio-effects. Excessive ions delivered into cells by NDs might have potential applications in tumor therapy. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Study of a hydraulic dicalcium phosphate dihydrate/calcium oxide-based cement for dental applications.

Science.gov (United States)

el-Briak, Hasna; Durand, Denis; Nurit, Josiane; Munier, Sylvie; Pauvert, Bernard; Boudeville, Phillipe

2002-01-01

By mixing CaHPO(4) x 2H(2)O (DCPD) and CaO with water or sodium phosphate buffers as liquid phase, a calcium phosphate cement was obtained. Its physical and mechanical properties, such as compressive strength, initial and final setting times, cohesion time, dough time, swelling time, dimensional and thermal behavior, and injectability were investigated by varying different parameters such as liquid to powder (L/P) ratio (0.35-0.7 ml g(-1)), molar calcium to phosphate (Ca/P) ratio (1.67-2.5) and the pH (4, 7, and 9) and the concentration (0-1 M) of the sodium phosphate buffer. The best results were obtained with the pH 7 sodium phosphate buffer at the concentration of 0.75 M. With this liquid phase, physical and mechanical properties depended on the Ca/P and L/P ratios, varying from 3 to 11 MPa (compressive strength), 6 to 10 min (initial setting time), 11 to 15 min (final setting time), 15 to 30 min (swelling time), 7 to 20 min (time of 100% injectability). The dough or working time was over 16 min. This cement expanded during its setting (1.2-5 % according to Ca/P and L/P ratios); this would allow a tight filling. Given the mechanical and rheological properties of this new DCPD/CaO-based cement, its use as root canal sealing material can be considered as classical calcium hydroxide or ZnO/eugenol-based pastes, without or with a gutta-percha point. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 447-453, 2002

Influence of sodium humate on the growth of Scenedesmus quadricauda (Turp. Brèb. and Gonium pectorale in the case of different calciumand iron doses

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Krystyna Juraja

2015-01-01

Full Text Available The influence of sodium humate on calcium and iron uptake by two species of algae was studied. It was found that sodium humate influence differentially the growth of these algae in various culture conditions by regulating the iron uptake. The action of sodium humate is especially favourable in non optimal pH of the medium and its effectiveness increases with time.

Biomimetic calcium phosphate coatings on recombinant spider silk fibres

Energy Technology Data Exchange (ETDEWEB)

Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A [Department of Tissue Regeneration, University of Twente, PO Box 217, 7500 AE Enschede (Netherlands); Hedhammar, My; Johansson, Jan [Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, the Biomedical Centre, Box 575, 751 23 Uppsala (Sweden); Blom, Tobias; Leifer, Klaus [Department of Engineering Sciences, Uppsala University, Box 534, S-751 21 Uppsala (Sweden)

2010-08-01

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

Biomimetic calcium phosphate coatings on recombinant spider silk fibres

International Nuclear Information System (INIS)

Yang Liang; Habibovic, Pamela; Van Blitterswijk, Clemens A; Hedhammar, My; Johansson, Jan; Blom, Tobias; Leifer, Klaus

2010-01-01

Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.

Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

Energy Technology Data Exchange (ETDEWEB)

Geraldo, Daniela A., E-mail: daniela.geraldo@unab.cl [Universidad Andres Bello, Departamento de Ciencias Quimicas (Chile); Arancibia-Miranda, Nicolas [CEDENNA, Center for the Development of Nanoscience and Nanotechnology (Chile); Villagra, Nicolas A. [Universidad Andres Bello, Laboratorio de Microbiologia, Facultad de Ciencias Biologicas (Chile); Mora, Guido C. [Universidad Andres Bello, Unidad de Microbiologia, Facultad de Medicina (Chile); Arratia-Perez, Ramiro [Universidad Andres Bello, Departamento de Ciencias Quimicas (Chile)

2012-12-15

The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV-Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

International Nuclear Information System (INIS)

Geraldo, Daniela A.; Arancibia-Miranda, Nicolás; Villagra, Nicolás A.; Mora, Guido C.; Arratia-Perez, Ramiro

2012-01-01

The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV–Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

Synthesis of CdTe QDs/single-walled aluminosilicate nanotubes hybrid compound and their antimicrobial activity on bacteria

Science.gov (United States)

Geraldo, Daniela A.; Arancibia-Miranda, Nicolás; Villagra, Nicolás A.; Mora, Guido C.; Arratia-Perez, Ramiro

2012-12-01

The use of molecular conjugates of quantum dots (nanocrystalline fluorophores) for biological purposes have received much attention due to their improved biological activity. However, relatively, little is known about the synthesis and application of aluminosilicate nanotubes decorated with quantum dots (QDs) for imaging and treatment of pathogenic bacteria. This paper describes for a first time, the use of single-walled aluminosilicate nanotubes (SWNT) (imogolite) as a one-dimensional template for the in situ growth of mercaptopropionic acid-capped CdTe QDs. This new nanohybrid hydrogel was synthesized by a simple reaction pathway and their enhanced optical properties were monitored by fluorescence and UV-Vis spectroscopy, confirming that the use of these nanotubes favors the confinement effects of net CdTe QDs. In addition, studies of FT-IR spectroscopy and transmission electron microscopy confirmed the non-covalent functionalization of SWNT. Finally, the antimicrobial activity of SWNT coated with CdTe QDs toward three opportunistic multi-resistant pathogens such as Salmonella typhimurium, Acinetobacter baumannii, and Pseudomonas aeruginosa were tested. Growth inhibition tests were conducted by exposing growing bacteria to CdTe QDs/SWNT hybrid compound showing that the new nano-structured composite is a potential antimicrobial agent for heavy metal-resistant bacteria.

Anodic and cathodic reactions in molten calcium chloride

International Nuclear Information System (INIS)

Fray, D.J.

2002-01-01

Calcium chloride is a very interesting electrolyte in that it is available, virtually free, in high purity form as a waste product from the chemical industry. It has a very large solubility for oxide ions, far greater than many alkali halides and other divalent halides and has the same toxicity as sodium chloride and also a very high solubility in water. Intuitively, on the passage of current, it is expected that calcium would be deposited at the cathode and chlorine would evolve at the anode. However, if calcium oxide is added to the melt, it is possible to deposit calcium and evolve oxygen containing gases at the anode, making the process far less polluting than when chlorine is evolved. This process is discussed in terms of the addition of calcium to molten lead. Furthermore, these reactions can be altered dramatically depending upon the electrode materials and the other ions dissolved in the calcium chloride. As calcium is only deposited at very negative cathodic potentials, there are several interesting cathodic reactions that can occur and these include the decomposition of the carbonate ion and the ionization of oxygen, sulphur, selenium and tellurium. For example, if an oxide is used as the cathode in molten calcium chloride, the favoured reaction is shown to be the ionization of oxygen O + 2e - → O 2- rather than Ca 2+ + 2 e- → Ca. The oxygen ions dissolve in the salt leaving the metal behind, and this leads to the interesting hypothesis that metal oxides can be reduced directly to the metal purely by the use of electrons. Examples are given for the reduction of titanium dioxide, zirconium dioxide, chromium oxide and niobium oxide and by mixing oxide powders together and reducing the mixed compact, alloys and intermetallic compounds are formed. Preliminary calculations indicate that this new process should be much cheaper than conventional metallothermic reduction for these elements. (author)

Flux Decoupling and Chemical Diffusion in Redox Dynamics in Aluminosilicate Melts and Glasses (Invited)

Science.gov (United States)

Cooper, R. F.

2010-12-01

Measurements of redox dynamics in silicate melts and glasses suggest that, for many compositions and for many external environments, the reaction proceeds and is rate-limited by the diffusive flux of divalent-cation network modifiers. Application of ion-backscattering spectrometry either (i) on oxidized or reduced melts (subsequently quenched before analysis) or (ii) on similarly reacted glasses, both of basalt-composition polymerization, demonstrates that the network modifiers move relative to the (first-order-rigid) aluminosilicate network. Thus, the textures associated with such reactions are often surprising, and frequently include metastable or unstable phases and/or spatial compositional differences. This response is only possible if the motion of cations can be decoupled from that of anions. In many cases, decoupling is accomplished by the presence in the melt/glass of transition-metal cations, whose heterovalency creates distortions in the electronic band structure resulting in electronic defects: electron “holes” in the valence band or electrons in the conduction band. (The prevalence of holes or electrons being a function of bulk chemistry and oxygen activity.) These electronic species make the melt/glass a “defect semiconductor.” Because (a) the critical issue in reaction dynamics is the transport coefficient (the product of species mobility and species concentration) and (b) the electronic species are many orders of magnitude more mobile than are the ions, very low concentrations of transition-metal ions are required for flux decoupling. For example, 0.04 at% Fe keeps a magnesium aluminosilicate melt/glass a defect semiconductor down to 800°C [Cook & Cooper, 2000]. Depending on composition, high-temperature melts can see ion species having a high-enough transport coefficient to allow decoupling, e.g., alkali cations in a basaltic melt [e.g., Pommier et al., 2010]. In this presentation, these ideas will be illustrated by examining redox dynamics

Regulation of proteolysis in Bacillus subtilis: effects of calcium ions and energy poisons

International Nuclear Information System (INIS)

O'Hara, M.B.; Hageman, J.H.

1987-01-01

Bacillus subtilis cells carry out extensive intracellular proteolysis (k = 0.15-0.23/h) during sporulation. Protein degradation was measured in cells growing in chemically defined sporulation medium, by following the release of [ 14 C]-leucine from the cells during spore formation. Sodium arsenate, carbonyl cyanide 3-chlorophenyl hydrazone, and sodium azide strongly inhibited proteolysis without altering cell viability greatly, which suggested that bulk proteolysis in B. subtilis is energy dependent. The authors have tested the hypothesis that the energy requirement may be for pumping in Ca 2+ . When [Ca 2+ ] was -6 , rates of proteolysis in sporulating cells were reduced 4-8 times that in cells in calcium ion- sufficient medium. Further, omission of Ca 2+ from the medium prevented the increase in the activity of the major intracellular serine protease. However, the presence of energy poisons in the media at levels which inhibited proteolysis, had no detectable effect on the uptake of by cells [ 45 Ca]. The authors concluded that B. subtilis cells required both metabolic energy and calcium ions for normal proteolysis

The effect of organic ligands on the crystallinity of calcium phosphate

Science.gov (United States)

van der Houwen, Jacqueline A. M.; Cressey, Gordon; Cressey, Barbara A.; Valsami-Jones, Eugenia

2003-03-01

Calcium phosphate phases precipitated under critical supersaturation were identified and studied in detail using X-ray powder diffraction, electron probe microanalysis, infrared spectroscopy (IR) and transmission electron microscopy. These synthetic calcium phosphates formed by spontaneous precipitation at pH 7, 25°C and 0.1 M ionic strength (NaCl as the background electrolyte). The combination of several methods allowed detailed characterisation of the calcium phosphates. The purpose of the work was to assess the influence of carboxylate ligands, specifically acetate and citrate, on the quality of the calcium phosphate precipitate. All precipitates were identified as non-stoichiometric, calcium-deficient hydroxylapatites (HAPs), containing carbonate, HPO 42-, sodium and chloride impurities. No other phases were found to be present in any of the precipitates. The presence of citrate resulted in a decrease in crystal size and a higher degree of apatite lattice imperfection in the precipitated HAP. Furthermore, IR spectroscopy showed a higher amount of carbonate present in that HAP, compared with the ones formed in the control and acetate experiments. An additional absorption band, in the infrared spectrum of the HAP formed in the presence of citrate, was observed at 1570 cm -1; this is interpreted as carboxyl groups bound to HAP.

Comparison of the removal of calcium hydroxide medicaments on the root canal treatment irrigated with manual and sonic agitation technique

Directory of Open Access Journals (Sweden)

Anna Muryani

2017-11-01

Full Text Available Introduction: Irrigation of the root canal system is an important part of the endodontic treatment principle which aims to improve the hygiene of the root canal system from any debris and medicament residue with the hydrodynamic system. Root irrigation technique can be done with the manual and sonic system by using 2.5% NaOCI irrigation solution. Calcium hydroxide is used as a medicament for root canal sterilization. Root canal treatment will fail due to the imperfect removal of calcium hydroxide residue. The objective of this research was to analyze the comparison of the removal of calcium hydroxide medicaments on the root canal treatment irrigated with manual and sonic agitation technique using 2.5% sodium hypochlorite solution. Methods: The methods used in this study was experimental laboratory. The sample used was 30 maxillary incisors. The teeth were then divided into two groups randomly, then the root canal preparation was done by the crown down technique with manual irrigation using 2.5% NaOCI solution. The radicular part of the teeth was then split longitudinally, given a standardized groove in the one-third of the apical part, then applied with water-solved calcium hydroxide. The teeth were unified afterwards by using flowable composites, then soaked in the artificial saliva at the temperature of 37ºC. The sample of the 1st group was irrigated by manual agitation technique, and the sample of the 2nd group 2 was irrigated by sonic agitation technique, then both were viewed by stereo microscope. The data results were analyzed by Kruskal-Wallis and Mann-Whitney tests. Results: The results of calcium hydroxide removal were different between the root canals that were irrigated using 2.5% sodium hypochlorite irrigation solution by manual agitation technique compared to the sonic agitation technique. Irrigation using 2.5% sodium hypochlorite irrigation solution with the sonic agitation techniques were proven to be more effective in lifting Ca

MoO{sub 3} incorporation in magnesium aluminosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Tan, Shengheng; Ojovan, Michael I.; Hyatt, Neil C.; Hand, Russell J.

2015-03-15

Molybdate has a very low solubility in silicate and borosilicate glass systems and its excess presence in nuclear waste glass can cause the formation of a readily soluble “yellow phase”. In this study, the incorporation of molybdenum oxide (MoO{sub 3}) in a magnesium aluminosilicate glass system has been investigated. The prepared glasses show a higher than 90% molybdenum retention rate and up to 5.34 mol% (12.28 wt%) MoO{sub 3} can be incorporated into these glasses without causing visible phase separation. The incorporation of MoO{sub 3} increases glass density, decreases glass transition and crystallisation temperatures and intensifies Raman bands assigned to vibrations of MoO{sub 4}{sup 2−} units. When excess molybdate is added liquid–liquid phase separation and crystallisation occurs. The separated phase is spherical, 200–400 nm in diameter and randomly dispersed. Based on powder X-ray diffraction, Raman spectroscopy and transmission electron microscopy, the separated phase is identified as MgMoO{sub 4}.

Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

Science.gov (United States)

Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

2017-07-01

Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

Development of alumino-silicate refractories in Ghana

International Nuclear Information System (INIS)

Kisiedu, A. K.; Tetteh, D.M.B.; Obiri, H. A.; Brenya, E. F.; Ayensu, A.

2008-01-01

Alumino-silicate (bauxite), andalusite, kaolin and clay were investigated for suitability in production of alumina, mullite and fireclay brick refractories. The raw materials were characterized by X-ray diffraction, differential thermal and silicate analyses. The x-ray diffraction analysis of alumina and mullite refractories fired at 1450 0 C, and fireclay bricks fired at 1350 0 C, indicated presence of corundum and alpha-alumina crystals. The values of thermal (fired) shrinkage, crushing, strength, porosity, water absorption and bulk density determined were 31.1%, 2.3 x 10 3 kg/m 3 , 4.86 x 10 6 N/m 2 and 13.2 % for mullite; 30.2%, 2.4 x 10 3 kg/m 3 , 3.20 x 10 6 N/m 2 and W = 12.8 % for alumina; and 25.2 %, 2.1 x 10 3 kg/m 3 , 2.61 x 10 6 N/m 2 and W = 11.8% for fireclay, respectively. Bauxite, andalusite and special kaolin were identified as potential raw materials for developing alumina and mullite refractories for construction of high temperature kilns and furnaces operating at 1350 0 C. The clay and kaolin minerals could be used to produce fireclay refractories for construction of incinerators operating at maximum temperatures of about 1000 0 C. The performance of the refractories was demonstrated by producing bricks to construct kilns and incinerators for the ceramic industry and hospitals. (au)

Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

Directory of Open Access Journals (Sweden)

2009-05-01

Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

Calcium in Mercury's Exosphere: Modeling MESSENGER Data

Science.gov (United States)

Burger, Matthew H.; Killen, Rosemary M.; McClintock, William E.; Merkel, Aimee; Vervack, Ronald J.; Sarantos, Menelaos; Sprague, Ann L.

2011-01-01

Mercury is surrounded by a surface-bounded exosphere comprised of atomic species including hydrogen, sodium, potassium, calcium, magnesium, and likely oxygen. Because it is collisionless. the exosphere's composition represents a balance of the active source and loss processes. The Mercury Atmospheric and Surface Composition Spectrometer (MASCS) on the MErcury Surface. Space ENvironment. GEochemistry. and Ranging (MESSENGER) spacecraft has made high spatial-resolution observations of sodium, calcium, and magnesium near Mercury's surface and in the extended, anti-sunward direction. The most striking feature of these data has been the substantial differences in the spatial distribution of each species, Our modeling demonstrates that these differences cannot be due to post-ejection dynamics such as differences in photo-ionization rate and radiation pressure. but instead point to differences in the source mechanisms and regions on the surface from which each is ejected. The observations of calcium have revealed a strong dawn/dusk asymmetry. with the abundance over the dawn hemisphere significantly greater than over the dusk. To understand this asymmetry, we use a Monte Carlo model of Mercury's exosphere that we developed to track the motions of exospheric neutrals under the influence of gravity and radiation pressure. Ca atoms can be ejected directly from the surface or produced in a molecular exosphere (e.g., one consisting of CaO). Particles are removed from the system if they stick to the surface or escape from the model region of interest (within 15 Mercury radii). Photoionization reduces the final weighting given to each particle when simulating the Ca radiance. Preliminary results suggest a high temperature ( I-2x 10(exp 4) K) source of atomic Ca concentrated over the dawn hemisphere. The high temperature is consistent with the dissociation of CaO in a near-surface exosphere with scale height <= 100 km, which imparts 2 eV to the freshly produced Ca atom. This

Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells

Science.gov (United States)

Robertson, Sarah Y. T.; Wen, Xin; Yin, Kaifeng; Chen, Junjun; Smith, Charles E.; Paine, Michael L.

2017-01-01

Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4), solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3), and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6) have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4) in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1) PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2) NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3) NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4) expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization. PMID:28588505

Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells

Directory of Open Access Journals (Sweden)

Sarah Y. T. Robertson

2017-05-01

Full Text Available Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4, solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3, and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6 have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4 in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1 PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2 NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3 NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4 expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization.

Toxicity of inhaled 90Sr in fused aluminosilicate particles in beagle dogs. VIII

International Nuclear Information System (INIS)

Snipes, M.B.; Hahn, F.F.; Muggenburg, B.A.; Mauderly, J.L.; McClellan, R.O.; Pickrell, J.A.

1977-01-01

Studies on the metabolism, dosimetry and biological effects of 90 Sr inhaled in a relatively insoluble form by Beagle dogs have continued during the past year to define the biological consequences of inhaling this important radionuclide in a form which has a long retention time in the lung. One hundred and six dogs were exposed to a polydisperse aerosol of fused aluminosilicate particles labeled with 90 Sr. Initial lung burdens ranged from 0.21 to 94 μCi 90 Sr per kilogram of body weight (μCi/kg). Eighteen control dogs were exposed to an aerosol of stable strontium in fused aluminosilicate particles. These 124 dogs were assigned to the longevity study. An additional 26 dogs were exposed similarly to achieve lung burdens of approximately 1.5 to 12 μCi/kg and assigned for sacrifice at intervals after exposure to define metabolism and dosimetry of this aerosol in Beagle dogs. Of the longevity dogs, 33 dogs having initial lung burdens of 16 to 94 μCi 90 Sr/kg and cumulative doses to lung of 40,000 to 96,000 rads have died from radiation pneumonitis and/or pulmonary fibrosis from 159 to 2373 days after exposure. Thirty-one dogs with initial lung burdens of 3.7 to 36 μCi 90 Sr/kg and cumulative doses to lung of 13,000 to 68,000 rads have died from hemangiosarcomas in the lung or heart between 644 and 2565 days after exposure. In addition, one dog developed a bronchioloalveolar carcinoma, another developed epidermoid carcinoma of the lung, another died of pneumonia while recovering from anesthesia, one dog died at 1821 days after exposure with a hemangiosarcoma of the spleen and two dogs developed squamous cell carcinomas in the nasal cavity. The remaining exposed dogs and controls of the longevity study are surviving at 1022 to 2803 days after exposure

Dendritic calcium conductances generate high-frequency oscillation in thalamocortical neurons

OpenAIRE

Pedroarena, Christine; Llinás, Rodolfo

1997-01-01

Cortical-projecting thalamic neurons, in guinea pig brain slices, display high-frequency membrane potential oscillations (20–80 Hz), when their somata are depolarized beyond −45 mV. These oscillations, preferentially located at dendritic sites, are supported by the activation of P/Q type calcium channels, as opposed to the expected persistent sodium conductance responsible for such rhythmic behavior in other central neurons. Short hyperpolarizing pulses reset the phase and transiently increas...

Calcium paradox and calcium entry blockers

NARCIS (Netherlands)

Ruigrok, T.J.C.; Slade, A.M.; Nayler, W.G.; Meijler, F.L.

1984-01-01

Reperfusion of isolated hearts with calcium-containing solution after a short period of calcium-free perfusion results in irreversible cell damage (calcium paradox). This phenomenon is characterized by an excessive influx of calcium into the cells, the rapid onset of myocardial contracture,

Calcium-Magnesium-Alumino-Silicates (CMAS) Reaction Mechanisms and Resistance of Advanced Turbine Environmental Barrier Coatings for SiC/SiC Ceramic Matrix Composites

Science.gov (United States)

Zhu, Dongming; Costa, Gustavo; Harder, Bryan J.; Wiesner, Valerie L.; Hurst, Janet B.; Puleo, Bernadette J.

2017-01-01

Environmental barrier coatings (EBCs) and SiC/SiC ceramic matrix composites (CMCs) systems will play a crucial role in future turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. The development of prime-reliant environmental barrier coatings is an essential requirement to enable the applications of the 2700-3000 F EBC - CMC systems. This presentation primarily focuses on the reaction mechanisms of advanced NASA environmental barrier coating systems, when in contact with Calcium-Magnesium Alumino-Silicates (CMAS) at high temperatures. Advanced oxide-silicate defect cluster environmental barrier coatings are being designed for ultimate balanced controls of the EBC temperature capability and CMAS reactivity, thus improving the CMAS resistance. Further CMAS mitigation strategies are also discussed.

Spying on Fe ions and their role in modified aluminosilicates during the sorption of anions using solid-state NMR spectroscopy

Czech Academy of Sciences Publication Activity Database

Kobera, Libor; Abbrent, Sabina; Holcova, L.; Urbanová, Martina; Koloušek, D.; Doušová, B.; Brus, Jiří

2017-01-01

Roč. 241, 15 March (2017), s. 115-122 ISSN 1387-1811 R&D Projects: GA ČR(CZ) GA13-24155S; GA ČR(CZ) GA16-13778S Institutional support: RVO:61389013 Keywords : paramagnetic NMR shift * solid-state NMR * aluminosilicate Subject RIV: JN - Civil Engineering OBOR OECD: Civil engineering Impact factor: 3.615, year: 2016

Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F

Directory of Open Access Journals (Sweden)

Tatiana Pyatina

2016-05-01

Full Text Available An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersive X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 µm and greater compressive strength after 300 °C curing. Mechanical properties of the set cements were not compromised by the retarder.

Effect of Tartaric Acid on Hydration of a Sodium-Metasilicate-Activated Blend of Calcium Aluminate Cement and Fly Ash F.

Science.gov (United States)

Pyatina, Tatiana; Sugama, Toshifumi; Moon, Juhyuk; James, Simon

2016-05-27

An alkali-activated blend of aluminum cement and class F fly ash is an attractive solution for geothermal wells where cement is exposed to significant thermal shocks and aggressive environments. Set-control additives enable the safe cement placement in a well but may compromise its mechanical properties. This work evaluates the effect of a tartaric-acid set retarder on phase composition, microstructure, and strength development of a sodium-metasilicate-activated calcium aluminate/fly ash class F blend after curing at 85 °C, 200 °C or 300 °C. The hardened materials were characterized with X-ray diffraction, thermogravimetric analysis, X-ray computed tomography, and combined scanning electron microscopy/energy-dispersive X-ray spectroscopy and tested for mechanical strength. With increasing temperature, a higher number of phase transitions in non-retarded specimens was found as a result of fast cement hydration. The differences in the phase compositions were also attributed to tartaric acid interactions with metal ions released by the blend in retarded samples. The retarded samples showed higher total porosity but reduced percentage of large pores (above 500 µm) and greater compressive strength after 300 °C curing. Mechanical properties of the set cements were not compromised by the retarder.

Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.

Science.gov (United States)

Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

2012-08-28

We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide.

Opiate-like excitatory effects of steroid sulfates and calcium-complexing agents given cerebroventricularly.

Science.gov (United States)

LaBella, F S; Havlicek, V; Pinsky, C

1979-01-12

Intracerebroventricular administration of 10--20 microgram of steroid-O-sulfates induced hypermotility, agitation, salivation, EEG abnormalities, stereotypies, wet dog shakes and seizures. Equivalent effects resulted from 30--200 microgram morphine sulfate (H2SO4 salt), 50 microgram EGTA or 300--400 microgram of sodium sulfate or phosphate, but not chloride, nitrate or acetate. Non-steroid sulfates, steroid glucuronides and steroid phosphates were inactive. Naloxone, previously found to antagonize the excitatory effects of androsterone sulfate, failed to antagonize those of cortisol sulfate, sodium sulfate or EGTA. These findings suggest a role for extracellular calcium ions and for sulfate derived from circulating steroids in central responses to opiates.

Chemical alteration of calcium silicate hydrates in saline groundwater. Mechanism of sorption of Na on C-S-H and effect of NaCl on leaching of Ca from C-S-H

International Nuclear Information System (INIS)

Sugiyama, Daisuke; Fujita, Tomonari

2004-01-01

In the concept for TRU waste disposal in Japan, cement is a potential waste packaging and backfilling material and is expected to provide chemical containment. In the presence of some reactive ions in a saline groundwater, the chemical properties of cement materials should be affected. In this study, the mechanism of sorption of sodium (Na) on C-S-H and the effect of sodium chloride (NaCl) concentration on dissolution of Calcium Silicate Hydrate (C-S-H) are discussed by measuring the sorption isotherm of sodium onto C-S-H gel (Ca/Si = 0.65-1.2). Based on the experimental results, it is showed that sodium sorbs by substitution for Ca in C-S-H phases and leaching of Ca from C-S-H is enhanced in NaCl solution ( -1 mol dm -3 ). The results of sorption experiments are reasonably well modelled by the ion-exchange model assuming some calcium sites with different ion-exchange log K values. It is also suggested that the dissolution of C-S-H can be modelled reasonably well by considering the effect of ionic strength on activity coefficients of aqueous species for high Ca/Si ratio of C-S-H, and the effect of exchange of sodium with calcium of C-S-H on leaching of Ca becomes obvious for lower Ca/Si ratio of C-S-H. (author)

Effects of ethanol on calcium transport across the liver cell plasma membrane

International Nuclear Information System (INIS)

Bernstein, J.; Santacana, G.

1987-01-01

The effect of ethanol on calcium transport by the liver cell was studied by using a rat liver slice preparation. Ethanol was shown to decrease by about 30% the rate constant for 45 Ca efflux from the intracellular compartment. This inhibitory effect of ethanol was not observed in the absence of Ca 2+ or Na + from the incubation medium. Ethanol was also shown to greatly increase non-insulin calcium uptake by liver slices. This effect of ethanol appeared to be dose dependent and was not observed in the absence of Na + from the incubation medium. The ability of ethanol to increase calcium uptake by the hepatocyte was completely blocked by 1 mM Amiloride. Amiloride, however, did not affect the increased entry of either Na + or Ca 2+ produced by 10 mM Ouabain, a specific inhibitor of the sodium pump. Carbon tetrachloride (CCl 4 ), a well known hepatotoxin, also increased calcium uptake by the hepatocyte. Amiloride, however, was not able to block the CCl 4 -induced calcium uptake. These results suggest that ethanol activates a Na + entry pathway, probably represented by a Na + /H + exchanger, which in turn stimulates an entry of Ca 2+ through a Na + /Ca 2+ exchange mechanism located in the plasma membrane of the hepatocyte

Effect of maternal excessive sodium intake on postnatal brain development in rat offspring.

Science.gov (United States)

Shin, Jung-a; Ahn, Young-mo; Lee, Hye-ah; Park, Hyesook; Kim, Young-ju; Lee, Hwa-young

2015-04-01

Postnatal brain development is affected by the in utero environment. Modern people usually have a high sodium intake. The aim of this study was to investigate the effect of sodium hyperingestion during pregnancy on the postnatal brain development of rat offspring. The sodium-overloaded rats received 1.8% NaCl in their drinking water for 7 days during the last week of gestation. Their body weight, urine, and blood levels of sodium and other parameters were measured. Some rats were sacrificed at pregnancy day 22 and the weight and length of the placenta and foetus were measured. The cerebral cortex and hippocampus were obtained from their offspring at postnatal day 1 and at postnatal weeks 1, 2, 4, and 8. Western blot analyses were conducted with brain tissue lysates. The sodium-overloaded animals had decreased weight gain in the last week of gestation as well as decreased food intake, increased water intake, urine volume, urine sodium, and serum sodium. There were no differences in placental weight and length. The foetuses of sodium-overloaded rats showed decreased body weight and size, and this difference was maintained postnatally for 2 weeks. In the cerebral cortex and hippocampus of the offspring, the protein levels of myelin basic protein, calmodulin/calcium-dependent protein kinase II, and brain-derived neurotrophic factor were decreased or aberrantly expressed. The present data suggest that increased sodium intake during pregnancy affects the brain development of the offspring.

Exhaust gas purification with sodium bicarbonate. Analysis and evaluation; Abgasreinigung mit Natriumhydrogencarbonat. Analyse und Bewertung

Energy Technology Data Exchange (ETDEWEB)

Quicker, Peter; Rotheut, Martin; Schulten, Marc [RWTH Aachen Univ. (Germany). Lehr- und Forschungsgebiet Technologie der Energierohstoffe (TEER); Athmann, Uwe [dezentec ingenieurgesellschaft mbH, Essen (Germany)

2013-03-01

The dry exhaust gas cleaning uses sodium bicarbonate in order to absorb acid components of exhaust gases such as sulphur dioxide or hydrochloric acid. Recently, sodium and calcium based adsorbents are compared with respect to their economic and ecologic options. None of the investigations performed considered decidedly practical experiences from the system operation such as differences in the management, availability, personnel expenditure and maintenance expenditure. Under this aspect, the authors of the contribution under consideration report on exhaust gas cleaning systems using sodium carbonate as well as lime adsorbents. The operators of these exhaust gas cleaning systems were questioned on their experiences, and all relevant operational data (consumption of additives, consumption of energy, emissions, standstill, maintenance effort) were recorded and evaluated at a very detailed level.

Precipitation of Calcium Carbonate in the Presence of Urea at 293 K and 343 K

Directory of Open Access Journals (Sweden)

Białowicz Katarzyna

2014-06-01

Full Text Available The results of the precipitation of calcium carbonate from a waste post-distillation liquid (DS and a sodium bicarbonate saturated solution – both from the Solvay method – in the presence of urea are presented. The investigation was carried out at 293 K and 343 K. Reagent dosage times of 1, 5, 10, 20 and 30 min, and urea concentrations of 5, 6 and 10 mol/dm3 were applied. The granulometric composition, the values of bulk and packing densities and the absorptiveness sorption of water and paraffin oil from the obtained calcium carbonate were investigated.

Chemical durability of soda-lime-aluminosilicate glass for radioactive waste vitrification

International Nuclear Information System (INIS)

Eppler, F.H.; Yim, M.S.

1998-01-01

Vitrification has been identified as one of the most viable waste treatment alternatives for nuclear waste disposal. Currently, the most popular glass compositions being selected for vitrification are the borosilicate family of glasses. Another popular type that has been around in glass industry is the soda-lime-silicate variety, which has often been characterized as the least durable and a poor candidate for radioactive waste vitrification. By replacing the boron constituent with a cheaper substitute, such as silica, the cost of vitrification processing can be reduced. At the same time, addition of network intermediates such as Al 2 O 3 to the glass composition increases the environmental durability of the glass. The objective of this study is to examine the ability of the soda-lime-aluminosilicate glass as an alternative vitrification tool for the disposal of radioactive waste and to investigate the sensitivity of product chemical durability to variations in composition

Improvement of calcium mineral separation contrast using anionic reagents: electrokinetics properties and flotation

Science.gov (United States)

Lafhaj, Z.; Filippov, L. O.; Filippova, I. V.

2017-07-01

The flotation separation of salt type calcium minerals is problematic, due to the similarities in their same active Ca2+ related site for interaction with anionic collectors and similar physicochemical characteristics such as solubility, zero-point charge, surface speciation and Ca-site density. The work was performed to achieve effective and selective separation of the calcium-minerals using pure minerals samples: orange calcite with Mg impurities, optic calcite with impurities level and an apatite. The pure samples surface was examined using techniques sensitive near-surface like infrared spectroscopy (FTIR) and chemical composition was obtained by ICPMS. The isoelectric point (IEP) and point of zero charge (PZC) in electrolyte were recorded using electrophoresis method at different ionic strengths of the solution. Mechanisms of charge development at the mineral-water interface are discussed. The time of contact as important parameter for the charge equilibrium was deduced from kinetics study and fixed to 30 minutes. The difference in the values obtained between IEP and PZSE can be explained by the presence of a specific adsorption of cations and anions on the surface. The effect of pure anionic collectors such as oleic and linoleic acid were studied. At low pH, both collectors lead to a good recovery for the calcites. The flotation recovery of optic calcite at pH 9 with sodium oleate is higher than with sodium linoleate. At alkaline pH, apatite showed a better recovery with sodium linoleate.

Calcium phosphate stabilization of fly ash with chloride extraction.

Science.gov (United States)

Nzihou, Ange; Sharrock, Patrick

2002-01-01

Municipal solid waste incinerator by products include fly ash and air pollution control residues. In order to transform these incinerator wastes into reusable mineral species, soluble alkali chlorides must be separated and toxic trace elements must be stabilized in insoluble form. We show that alkali chlorides can be extracted efficiently in an aqueous extraction step combining a calcium phosphate gel precipitation. In such a process, sodium and potassium chlorides are obtained free from calcium salts, and the trace metal ions are immobilized in the calcium phosphate matrix. Moderate calcination of the chemically treated fly ash leads to the formation of cristalline hydroxylapatite. Fly ash spiked with copper ions and treated by this process shows improved stability of metal ions. Leaching tests with water or EDTA reveal a significant drop in metal ion dissolution. Hydroxylapatite may trap toxic metals and also prevent their evaporation during thermal treatments. Incinerator fly ash together with air pollution control residues, treated by the combined chloride extraction and hydroxylapatite formation process may be considered safe to use as a mineral filler in value added products such as road base or cement blocks.

The mode of inhibition of the Na+-K+ pump activity in mast cells by calcium

DEFF Research Database (Denmark)

Knudsen, T; Johansen, Torben

1989-01-01

, and hence the pump activity. This hypothesis is supported by the stimulation of pump activity produced by monensin, which is not inhibited by calcium. The enhancement of pump activity after exposure of calcium-deprived cells to EGTA might be the result of a further increase in the sodium permeability......1 The inhibition by calcium of the Na(+)-K+ pump in the plasma membrane of rat peritoneal mast cells was studied in pure populations of the cells by measuring the ouabain-sensitive uptake of the radioactive potassium analogue, 86rubidium (86Rb+). 2 Exposure of the cells to calcium induced a time......- and concentration-dependent decrease in the ouabain-sensitive K+(86Rb+)-uptake of the cells without influencing the ouabain-resistant uptake. The development of the inhibition required the presence of potassium in the medium in the millimolar range (1.5-8.0 mM), and it did not occur at a concentration of potassium...

Polymeric microcapsules poduction from sodium alginic acid for cell therapy

Directory of Open Access Journals (Sweden)

Ana Carolina Vale Campos Lisboa

2007-12-01

Full Text Available Development of polymeric materials has been increasingly emphasized in Biomedicine. Here, we evaluate the use of microcapsules made of Biodritin®, a biocompatible polymer compound which contains sodium alginic acid, a natural polymer extracted from algae, and Cis-Chondroitin sulfate, a glycosaminoglycan from the extracellular matrix. Gelation of this polymer into microcapsules is achieved by dropping the compound into BaCl2 or CaCl2 gelling solutions. A functional microcapsule is dependent on its permeability, mechanical stability, immunoisolation capacity and biocompatibility. The mechanical stability of Biodritin-barium and Biodritin-calcium microcapsules was investigated after rotational stress upon in vitro culture and in vivo implantation. Viability studies of encapsulated cells were also performed to assess other functional parameters of the microcapsules. When subject to rotational stress, Biodritin-barium microcapsules exhibited breaks, whereas the Biodritin-calcium microcapsules did not. Both kinds of Biodritin® microcapsules proved to be mechanically resistant in in vitro and in vivo studies. However, the Biodritin-calcium material was found to be more elastic while the Biodritin-barium microcapsules displayed a more plastic behavior. These properties seem to be determinant for viability of the encapsulated cell’s, since the Biodritin-calcium microcapsules presented more viable cells than the Biodritin-barium microcapsules.

A model of propagating calcium-induced calcium release mediated by calcium diffusion

NARCIS (Netherlands)

Backx, P. H.; de Tombe, P. P.; van Deen, J. H.; Mulder, B. J.; ter Keurs, H. E.

1989-01-01

The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium

Development and gamma scintigraphy evaluation of gastro retentive calcium ion-based oral formulation: an innovative approach for the management of gastro-esophageal reflux disease (GERD).

Science.gov (United States)

Sharma, Braj Gaurav; Khanna, Kushagra; Kumar, Neeraj; Nishad, Dhruv K; Basu, Mitra; Bhatnagar, Aseem

2017-11-01

Calcium chloride is an essential calcium channel agonist which plays an important role in the contraction of muscles by triggering calcium channel. First time hypothesized about its role in the treatment of GER (gastro-esophageal reflux) and vomiting disorder due to its local action. There are two objectives covered in this study as first, the development and optimization of floating formulation of calcium chloride and another objective was to evaluate optimized formulation through gamma scintigraphy in human subjects. Gastro retentive formulation of calcium chloride was prepared by direct compression method. Thirteen tablet formulations were designed with the help of sodium chloride, HPMC-K4M, and carbopol-934 along with effervescing agent sodium bicarbonate and citric acid. Formulation (F8) fitted best for Korsmeyer-Peppas equation with an R 2 value of 0.993. The optimized formulation was radiolabelled with 99m Tc-99 m pertechnetate for its evaluation by gamma scintigraphy. Gastric retention (6 h) was evaluated by gamma scintigraphy in healthy human subjects and efficacy of present formulation confirmed in GER positive human subjects. Gamma scintigraphy results indicated its usefulness in order to manage GERD. Stability studies of the developed formulation were carried out as per ICH guidelines for region IV and found out to be stable for 24 months.

Evaluation of aluminosilicate glass sintering during differential scanning calorimetry

International Nuclear Information System (INIS)

Souza, Juliana Pereira de

2015-01-01

In this work a difference in the baseline in differential scanning calorimetry analyses, observed in a work where aluminosilicate glasses microspheres containing Ho were studied for application in selective internal radiotherapy as hepatocellular carcinoma treatment, was studied. The glasses with nominal composition 53,7 SiO 2 .10,5 Al 2 O 3 . 35,8 MgO in %mol were produced from traditional melting. The first obtained were milled and sieved in the range of 45 a 63 μm. The material was used to produce glass microspheres by the gravitational fall method. The glass powder and the microspheres were characterized by X ray fluorescence spectrometry, laser diffraction, X ray diffraction, differential scanning calorimetry, differential thermal analysis, thermogravimetry, mass spectrometry, and scanning electron microscopy. After the thermal analyses, pellets were formed in the crucibles and were analyzed by scanning electron microscopy, X ray diffraction, and He pycnometry. The difference in the baseline was associated to the viscous flow sintering process and happens because of the decrease in the detected heat flow due to the sample shrinkage. Other events as concurrent crystallization with the sintering process were also studied. (author)

Solubilities of sodium nitrate, sodium nitrite, and sodium aluminate in simulated nuclear waste

International Nuclear Information System (INIS)

Reynolds, D.A.; Herting, D.L.

1984-09-01

Solubilities were determined for sodium nitrate, sodium nitrite, and sodium aluminate in synthetic nuclear waste liquor. Solubilities were determined as a function of temperature and solution composition (concentrations of sodium hydroxide, sodium nitrate, sodium nitrite, and sodium aluminate). Temperature had the greatest effect on the solubilities of sodium nitrate and sodium nitrite and a somewhat lesser effect on sodium aluminate solubility. Hydroxide had a great effect on the solubilities of all three salts. Other solution components had minor effects. 2 references, 8 figures, 11 tables

Controlled release studies of calcium alginate hydrogels

International Nuclear Information System (INIS)

Rendevski, S.; Andonovski, A.; Mahmudi, N.

2012-01-01

Controlled release of substances in many cases may be achieved from calcium alginate hydrogels. In this research, the time dependence of the mass of released model substance bovine serum albumin (BSA) from calcium alginate spherical hydrogels of three different types (G/M ratio) have been investigated. The hydrogels were prepared with the drop-wise method of sodium alginate aqueous solutions with concentration of 0.02 g/cm 3 with 0.01 g/cm 3 BSA and a gelling water bath of chitosan in 0.2 M CH 3 COOH/0.4 M CH 3 COONa with added 0.2 M CaCl 2 .The hydrogel structures were characterized by dynamic light scattering and scanning electron microscopy. The controlled release studies were conducted by UV-Vis spectrophotometry of the released medium with p H=7 at 37 °C. The results showed that the model of osmotic pumping is the dominant mechanism of the release. Also, large dependences of the release profile on the homogeneity of the hydrogels were found. (Author)

Evaluation of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to prevent enamel loss after erosive challenges using an intra-oral erosion model.

Science.gov (United States)

Sullivan, R; Rege, A; Corby, P; Klaczany, G; Allen, K; Hershkowitz, D; Godder, B; Wolff, M

2014-01-01

The objective of this study was to assess the ability of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin' Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP) to prevent enamel loss from an erosive acid challenge in comparison to a silica-based dentifrice with 1450 ppm fluoride as MFP using an intra-oral erosion model. The intra-oral clinical study used a double blind, two-treatment, crossover design. A palatal retainer was used to expose the enamel specimens to the oral environment during the five-day treatment period. The retainer was designed to house three partially demineralized bovine enamel samples. The study population was composed of 24 adults, ages 18 to 70 years. The study consisted of two treatment periods, with a washout period lasting seven (+/- three) days preceding each treatment phase. A silica-based dentifrice without fluoride was used during the washout period. The Test Dentifrice used in this study contained 8% arginine and calcium carbonate (Pro-Argin Technology), and 1450 ppm fluoride as sodium monofluorophosphate (MFP). The Control Dentifrice was silica-based and contained 1450 ppm fluoride as MFP. The treatment period lasted five days, during which the panelists wore the retainer 24 hours a day (except during meals and the ex vivo acid challenges) and brushed with their assigned product while wearing the retainer. The panelists brushed once in the morning and once in the evening each day for one minute, followed by a one-minute swish with the slurry and a rinse with 15 ml of water. The panelists brushed only their teeth and not the specimens directly. There were four ex vivo challenges with 1% citric acid dispersed throughout the day: two in the morning, one in the afternoon, and one in the evening. Mineral loss was monitored by a quantitative light fluorescence (QLF) technique. Twenty-three of 24 subjects successfully completed the study. The one subject who did not complete the study did so for

Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

Science.gov (United States)

Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward

2013-01-01

To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

Science.gov (United States)

Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

2008-02-28

The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

Absorption and luminescence characteristics of {sup 5}I{sub 7} ↔ {sup 5}I{sub 8} transitions of the holmium ion in Ho{sup 3+}-doped aluminosilicate preforms and fibres

Energy Technology Data Exchange (ETDEWEB)

Ryabochkina, P A; Chabushkin, A N [N.P. Ogarev Mordovian State University, Saransk (Russian Federation); Kosolapov, A F [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation); Kurkov, A S [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2015-02-28

We have obtained the spectral dependences of the absorption cross sections for the Ho{sup 3+} {sup 5}I{sub 8} → {sup 5}I{sub 6} and {sup 5}I{sub 8} → {sup 5}I{sub 7} transitions in Ho{sup 3+}-doped aluminosilicate fibres and the spectral dependence of the stimulated emission cross section for the Ho{sup 3+} {sup 5}I{sub 7} → {sup 5}I{sub 8} laser transition in Ho{sup 3+}-doped aluminosilicate fibre preforms. The lifetime of the Ho{sup 3+} {sup 5}I{sub 7} upper laser level in the preforms has been determined. (lasers)

Dietary supplementation with sodium bicarbonate improves calcium absorption and eggshell quality of laying hens during peak production.

Science.gov (United States)

Jiang, M J; Zhao, J P; Jiao, H C; Wang, X J; Zhang, Q; Lin, H

2015-01-01

The advantage of supplemental sodium bicarbonate (NaHCO3) on eggshell quality in laying hens changes with age. Besides increasing calcium (Ca) secretion in the eggshell gland, it may improve Ca absorption in the intestine or kidney. Hy-Line Brown layers (n = 384), 25 weeks of age, were allocated to two treatment groups in two experiments, each of which included 4 replicates of 24 hens. Hens were fed a basal diet (control) or the basal diet containing 3 g NaHCO3 g/kg for 50 or 20 weeks in Experiment 1 or 2, respectively. A 24-h continuous lighting regimen was used to allow hens to consume the dietary supplements during the period of active eggshell formation. In Experiment 1, particularly from 25 to 50 weeks of age, and in Experiment 2, NaHCO3 supplementation favoured hen-d egg production at the expense of lower egg weight. The increased eggshell thickness should have nothing to do with the additional eggshell formation, because of the unchanged egg mass and daily eggshell calcification. At 35 weeks of age in both experiments, NaHCO3 supplementation increased duodenal expression of calbindin-d28k (CaBP-D28k) protein, contributing to higher Ca retention and balance. From 50 to 75 weeks of age in Experiment 1, the hens had little response to NaHCO3 supplementation and showed a negative trend on eggshell thickness and strength. It is concluded that dietary supplementation with 3 g NaHCO3 g/kg improves Ca absorption and eggshell quality of laying hens during the peak but not late production period, with the introduction of continuous lighting.

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

International Nuclear Information System (INIS)

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

1984-01-01

Metabolic balance studies were undertaken to determine whether sodium bicarbonate (NaHCO 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) 2 D 3 /day]. Feeding bicarbonate lowered urinary Ca but raised fecal Ca so that Ca balance became less positive. However, 1,25(OH) 2 D 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) 2 D 3 . Changes in net Ca absorption induced by bicarbonate may occur at a point in the gut distal to the duodenum since duodenal 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) 2 D 3 metabolism because it is manifest in animals receiving high doses of 1,25(OH) 2 D 3 , which stimulate alimentary Ca absorption maximally, and because bicarbonate-fed rats are able to respond normally to exogenous 1,25(OH) 2 D 3 by increasing their net absorption of Ca and P. In view of this demonstration that NaHCO 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

Jatropha curcas leaves analysis, reveals it as mineral source for low sodium diets.

Science.gov (United States)

Méndez, Lucero; Rojas, Janne; Izaguirre, César; Contreras, Billmary; Gómez, Rubén

2014-12-15

Jatropha curcas is a perennial herb, belonging to the family Euphorbiaceae, found in countries such as India, Mexico and Venezuela. In the present study, proximate composition and mineral content on the leaves of J. curcas was analysed and compared to spinach (Spinacia oleracea L.) using a ICP-AES. The bromatologic test (dry material) results for ashes, proteins, lipids and carbohydrates revealed 23.4%, 28.0%, 3.2% and 45.4% for J. curcas; whereas for S. oleracea values were 28.9%, 20.8%, 0.5% and 49.9%. Furthermore, minerals found in both species ashes were: calcium, potassium, magnesium, iron and phosphorus, resulting that leaves of J. curcas are composed by three times the iron and calcium amount comparing to spinach; while sodium was absent from the former species. In this study Cu and Zn were found only in spinach, while Pb and As were not detected in any of the studied species. These results indicate that J. curcas leaves might be considered as mineral source suitable for animal and human consumption, especially for people who requires a low sodium diet. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

International Nuclear Information System (INIS)

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.; Wang, Zheming

2007-01-01

The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH · 1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reduction of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity

Silica, alumina and aluminosilicates as solid stationary phases in gas chromatography

Directory of Open Access Journals (Sweden)

S. Faramawy

2016-09-01

Full Text Available Silica, alumina and Aluminosilicates of different Si/Al ratios were prepared by conventional precipitation or co-precipitation methods and then subjected to thermal treatment at 800 °C. The parent and thermally treated materials were characterized by means of FTIR, SEM and thermal analysis (DTA and TGA in order to elucidate the main structural properties. Surface textural characteristics were investigated by means of nitrogen adsorption–desorption isotherms at −196 °C. Pore size distribution curves indicated the presence of mesopores (10–150 Å exhibiting maxima at 35 Å. The maxima were shifted toward higher values by increasing the alumina content. Thermodynamic parameters, ΔH, ΔG and ΔS, were determined by means of inverse gas chromatography using n-hexane as a probe. The untreated and thermally treated materials were tested as solid stationary phases in gas chromatography. The separation efficiency of various non polar and polar compounds was explained in terms of surface texture and thermodynamic parameters.

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

Energy Technology Data Exchange (ETDEWEB)

Enterría, Marina, E-mail: marina@incar.csic.es; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-15

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm{sup 3}/g, respectively. X-ray diffraction and N{sub 2} adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica.

Preparation of hierarchical micro-mesoporous aluminosilicate composites by simple Y zeolite/MCM-48 silica assembly

International Nuclear Information System (INIS)

Enterría, Marina; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M.D.

2014-01-01

Highlights: • Hierarchical micro-mesoporous aluminosilicates were synthesized. • Y zeolite core/MCM-48 silica shell structures were obtained. • Y zeolite favors the formation of the mesostructure. • Porosity and structure can be varied by modifying the preparation variables. • Duration of the hydrothermal step has a great effect on the materials properties. -- Abstract: A simple procedure to obtain hierarchical micro-mesoporous aluminosilicate composites was developed by growing MCM-48 silica over commercial Y zeolite. The obtained hierarchical composites have a microporous core and a mesoporous shell. The process consists in assembling dispersed Y zeolite with a mesoporous silica phase that is formed “in situ” by “soft-templating” with cetryltrimethylammonium bromide (CTAB) as surfactant. The Y zeolite/MCM-48 silica ratio and aging time were varied to study their effects on the final porosity and structure of the hierarchical composites. The pore textural and structural characteristics of the composites did not match those of the corresponding Y zeolite/MCM-48 silica physical mixtures. This implies that the synthesized composites integrate micropores and mesopores in the same bulk. The obtained composites exhibited micropore and mesopore volumes ranging between 0.15–0.31 and 0.30–0.51 cm 3 /g, respectively. X-ray diffraction and N 2 adsorption results revealed that the presence of zeolite in the reaction medium favors the formation of mesopores in the obtained materials, especially for short hydrothermal treatments. TEM results showed that the obtained adsorbents are constituted by an integrated micro-mesoporous bimodal system in which Y zeolite is surrounded by a thin cover of MCM-48 silica

NCKX3 was compensated by calcium transporting genes and bone resorption in a NCKX3 KO mouse model.

Science.gov (United States)

Yang, Hyun; Ahn, Changhwan; Shin, Eun-Kyeong; Lee, Ji-Sun; An, Beum-Soo; Jeung, Eui-Bae

2017-10-15

Gene knockout is the most powerful tool for determination of gene function or permanent modification of the phenotypic characteristics of an animal. Existing methods for gene disruption are limited by their efficiency, time required for completion and potential for confounding off-target effects. In this study, a rapid single-step approach to knockout of a targeted gene in mice using zinc-finger nucleases (ZFNs) was demonstrated for generation of mutant (knockout; KO) alleles. Specifically, ZFNs to target the sodium/calcium/potassium exchanger3 (NCKX3) gene in C57bl/6j were designed using the concept of this approach. NCKX3 KO mice were generated and the phenotypic characterization and molecular regulation of active calcium transporting genes was assessed when mice were fed different calcium diets during growth. General phenotypes such as body weight and plasma ion level showed no distinct abnormalities. Thus, the potassium/sodium/calcium exchanger of NCKX3 KO mice proceeded normally in this study. As a result, the compensatory molecular regulation of this mechanism was elucidated. Renal TRPV5 mRNA of NCKX3 KO mice increased in both male and female mice. Expression of TRPV6 mRNA was only down-regulated in the duodenum of male KO mice. Renal- and duodenal expression of PTHR and VDR were not changed; however, GR mRNA expression was increased in the kidney of NCKX3 KO mice. Depletion of the NCKX3 gene in a KO mouse model showed loss of bone mineral contents and increased plasma parathyroid hormone, suggesting that NCKX3 may play a role in regulating calcium homeostasis. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparative effects of sodium channel blockers in short term rat whole embryo culture

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Mats F, E-mail: Mats.Nilsson@farmbio.uu.se [Department of Pharmaceutical Biosciences, Uppsala University (Sweden); Sköld, Anna-Carin; Ericson, Ann-Christin; Annas, Anita; Villar, Rodrigo Palma [AstraZeneca R and D Södertälje (Sweden); Cebers, Gvido [AstraZeneca R and D, iMed, 141 Portland Street, Cambridge, MA 02139 (United States); Hellmold, Heike; Gustafson, Anne-Lee [AstraZeneca R and D Södertälje (Sweden); Webster, William S [Department of Anatomy and Histology, University of Sydney (Australia)

2013-10-15

This study was undertaken to examine the effect on the rat embryonic heart of two experimental drugs (AZA and AZB) which are known to block the sodium channel Nav1.5, the hERG potassium channel and the L-type calcium channel. The sodium channel blockers bupivacaine, lidocaine, and the L-type calcium channel blocker nifedipine were used as reference substances. The experimental model was the gestational day (GD) 13 rat embryo cultured in vitro. In this model the embryonic heart activity can be directly observed, recorded and analyzed using computer assisted image analysis as it responds to the addition of test drugs. The effect on the heart was studied for a range of concentrations and for a duration up to 3 h. The results showed that AZA and AZB caused a concentration-dependent bradycardia of the embryonic heart and at high concentrations heart block. These effects were reversible on washout. In terms of potency to cause bradycardia the compounds were ranked AZB > bupivacaine > AZA > lidocaine > nifedipine. Comparison with results from previous studies with more specific ion channel blockers suggests that the primary effect of AZA and AZB was sodium channel blockage. The study shows that the short-term rat whole embryo culture (WEC) is a suitable system to detect substances hazardous to the embryonic heart. - Highlights: • Study of the effect of sodium channel blocking drugs on embryonic heart function • We used a modified method rat whole embryo culture with image analysis. • The drugs tested caused a concentration dependent bradycardia and heart block. • The effect of drugs acting on multiple ion channels is difficult to predict. • This method may be used to detect cardiotoxicity in prenatal development.

Comparative effects of sodium channel blockers in short term rat whole embryo culture

International Nuclear Information System (INIS)

Nilsson, Mats F; Sköld, Anna-Carin; Ericson, Ann-Christin; Annas, Anita; Villar, Rodrigo Palma; Cebers, Gvido; Hellmold, Heike; Gustafson, Anne-Lee; Webster, William S

2013-01-01

This study was undertaken to examine the effect on the rat embryonic heart of two experimental drugs (AZA and AZB) which are known to block the sodium channel Nav1.5, the hERG potassium channel and the L-type calcium channel. The sodium channel blockers bupivacaine, lidocaine, and the L-type calcium channel blocker nifedipine were used as reference substances. The experimental model was the gestational day (GD) 13 rat embryo cultured in vitro. In this model the embryonic heart activity can be directly observed, recorded and analyzed using computer assisted image analysis as it responds to the addition of test drugs. The effect on the heart was studied for a range of concentrations and for a duration up to 3 h. The results showed that AZA and AZB caused a concentration-dependent bradycardia of the embryonic heart and at high concentrations heart block. These effects were reversible on washout. In terms of potency to cause bradycardia the compounds were ranked AZB > bupivacaine > AZA > lidocaine > nifedipine. Comparison with results from previous studies with more specific ion channel blockers suggests that the primary effect of AZA and AZB was sodium channel blockage. The study shows that the short-term rat whole embryo culture (WEC) is a suitable system to detect substances hazardous to the embryonic heart. - Highlights: • Study of the effect of sodium channel blocking drugs on embryonic heart function • We used a modified method rat whole embryo culture with image analysis. • The drugs tested caused a concentration dependent bradycardia and heart block. • The effect of drugs acting on multiple ion channels is difficult to predict. • This method may be used to detect cardiotoxicity in prenatal development

FFTF vertical sodium storage tank preliminary thermal analysis

International Nuclear Information System (INIS)

Irwin, J.J.

1995-01-01

In the FFTF Shutdown Program, sodium from the primary and secondary heat transport loops, Interim Decay Storage (IDS), and Fuel Storage Facility (FSF) will be transferred to four large storage tanks for temporary storage. Three of the storage tanks will be cylindrical vertical tanks having a diameter of 28 feet, height of 22 feet and fabricated from carbon steel. The fourth tank is a horizontal cylindrical tank but is not the subject of this report. The storage tanks will be located near the FFTF in the 400 Area and rest on a steel-lined concrete slab in an enclosed building. The purpose of this work is to document the thermal analyses that were performed to ensure that the vertical FFTF sodium storage tank design is feasible from a thermal standpoint. The key criterion for this analysis is the time to heat up the storage tank containing frozen sodium at ambient temperature to 400 F. Normal operating conditions include an ambient temperature range of 32 F to 120 F. A key parameter in the evaluation of the sodium storage tank is the type of insulation. The baseline case assumed six inches of calcium silicate insulation. An alternate case assumed refractory fiber (Cerablanket) insulation also with a thickness of six inches. Both cases assumed a total electrical trace heat load of 60 kW, with 24 kW evenly distributed on the bottom head and 36 kW evenly distributed on the tank side wall

A STUDY OF ANTICONVULSANT EFFECT OF FLUNARIZINE AND NIFEDIPINE IN COMPARISON WITH SODIUM VALPROATE ON MES AND PTZ MODELS OF EPILEPSY IN ALBINO RATS

Directory of Open Access Journals (Sweden)

Umesh G.

2015-03-01

Full Text Available BACKGROUND : CA +2 ions are involved in initiation as well as spread of seizures. Hence current study was undertaken to evaluate the anticonvulsant effect of calcium channel blockers flunarizine, nifedipine and compare their efficacy with that of sodium valproate, the broad spectrum anticonvulsant in MES and PTZ induced seizures in albino rats. MATERIALS AND METHODS : Albino rats were treated with nife dipine 2.5mg/kg, 5mg/kg, flunarizine 7.5mg/kg,15mg/kg and sodium valproate 250mg/kg bodyweight intraperitoneally and the effects were observed in MES and PTZ models of epilepsy. The parameters observed in MES model was , duration of HLTE phase . Convulsive p hase, and post ictal depressive phase. In PTZ model duration of seizure latency, duration of convulsion , and duration post ictal depression were observed. RESULTS : our study demonstrated that both calcium channel blockers afford protection against convulsi ons induced in both models, and flunarizine affords higher degree of protection than nifedipine, with its efficacy almost approaching that of sodium valproate. CONCLUSION : Flunarizine has significant, while nifedipine has moderate degree of anticonvulsant activity as compared to sodium valproate

Deuterium oxide normalizes blood pressure and vascular calcium uptake in Dahl salt-sensitive hypertensive rats

International Nuclear Information System (INIS)

Vasdev, S.; Prabhakaran, V.; Sampson, C.A.

1990-01-01

This study examined the effect of 25% deuterium oxide in drinking water on systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas of Dahl salt-sensitive rats on 0.4% (low) and 8% (high) sodium chloride (salt) diet. Twenty-four rats were divided into four groups. Groups I and II were on the low salt diet and groups III and IV on the high salt diet from 6 weeks of age. Additionally, at 10 weeks of age groups I and III were placed on 100% water and groups II and IV on 25% deuterium oxide. At 14 weeks, systolic blood pressure, uptakes of calcium, and rubidium 86 by aortas were significantly higher (p less than 0.01) in rats on the high salt diet as compared with those on the low salt diet. Deuterium oxide intake normalized systolic blood pressure and aortic calcium uptake but not aortic rubidium 86 uptake in hypertensive rats on the high salt diet. Deuterium oxide had no effect on blood pressure or aortic calcium uptake in rats on the low salt diet. The parallel increase in systolic blood pressure and vascular calcium uptake suggests that increased calcium uptake mechanisms are associated with hypertension in salt-sensitive Dahl rats. Furthermore, deuterium oxide appears to normalize elevated blood pressure in salt-sensitive hypertensive rats by normalizing elevated vascular (aortic) calcium uptake

Surface functionalization of aluminosilicate nanotubes with organic molecules

Directory of Open Access Journals (Sweden)

Wei Ma

2012-02-01

Full Text Available The surface functionalization of inorganic nanostructures is an effective approach for enriching the potential applications of existing nanomaterials. Inorganic nanotubes attract great research interest due to their one-dimensional structure and reactive surfaces. In this review paper, recent developments in surface functionalization of an aluminosilicate nanotube, “imogolite”, are introduced. The functionalization processes are based on the robust affinity between phosphate groups of organic molecules and the aluminol (AlOH surface of imogolite nanotubes. An aqueous modification process employing a water soluble ammonium salt of alkyl phosphate led to chemisorption of molecules on imogolite at the nanotube level. Polymer-chain-grafted imogolite nanotubes were prepared through surface-initiated polymerization. In addition, the assembly of conjugated molecules, 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid (HT3P and 2-(5’’-hexyl-2,2’:5’,2’’-terthiophen-5-ylethylphosphonic acid 1,1-dioxide (HT3OP, on the imogolite nanotube surface was achieved by introducing a phosphonic acid group to the corresponding molecules. The optical and photophysical properties of these conjugated-molecule-decorated imogolite nanotubes were characterized. Moreover, poly(3-hexylthiophene (P3HT chains were further hybridized with HT3P modified imogolite to form a nanofiber hybrid.

Crescimento, trocas gasosas e potencial osmótico da bananeira-'Prata', submetida a diferentes doses de sódio e cálcio em solução nutritiva Growth, gaseous exchange and osmotic potential of banana 'Prata' plants, exposed to different concentrations of sodium and calcium in nutritive solution

Directory of Open Access Journals (Sweden)

LUDMILA LAFETÁ DE MELO NEVES

2002-08-01

Full Text Available O cálcio vem sendo utilizado com o intuito de incrementar tolerância a sais nas plantas, pois sabe-se que a salinidade restringe o crescimento e a produtividade de muitas culturas. Este estudo teve por objetivo avaliar os efeitos da aplicação de sódio e cálcio sobre o crescimento inicial, trocas gasosas e potencial osmótico da bananeira (Musa spp. 'Prata' (AAB. Foi utilizado o delineamento experimental em blocos casualizados, com arranjo fatorial 4 x 4 [ 4 doses de sódio ( 0; 5; 10; 15 mmol L-1 e 4 de cálcio ( 2; 4; 8; 12 mmol L-1] e 3 repetições. A emissão total de folhas e o potencial osmótico das plantas não foram influenciados pelos tratamentos. O aumento dos níveis de sódio na solução promoveu redução significativa na massa fresca da parte aérea, altura, área foliar, diâmetro do pseudocaule e massa seca das plantas. A presença de 5 mmol L-1 de Na na solução favoreceu as trocas gasosas. O aumento dos níveis de cálcio na solução promoveu a redução da massa fresca da parte aérea, altura e área foliar da bananeira-'Prata'.The Calcium has been used to increase salt tolerance in plants since salinity restricts growth and productivity in many crops. This study was conducted with the objective of evaluating the effects of sodium and calcium application on the initial growth, gaseous exchange and osmotic potential of banana (Musa spp. 'Prata' plants (AAB. The experimental layout was a 4 x 4 factorial with three replicates in a randomized complete block design. The factors tested were concentrations of sodium (0; 5; 10; 15 mmol L-1 and calcium (2; 4; 8; 12 mmol L-1. The total emition of leaves and the osmotic potential of the plants were not influenced by the treatments. However, the increase in concentrations of sodium in the nutritive solution resulted in significant reduction of the fresh weight of aerial plant parts, height and leaf area of the plants, diameter of the pseudostem, and dry weight of the plants. The

Silver-Loaded Aluminosilicate Aerogels As Iodine Sorbents

Energy Technology Data Exchange (ETDEWEB)

Riley, Brian J. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Kroll, Jared O. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Peterson, Jacob A. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Matyáš, Josef [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Olszta, Matthew J. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Li, Xiaohong [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Vienna, John D. [Pacific Northwest National Laboratory, Richland, Washington 99354, United States

2017-09-14

This paper discusses the development of aluminosilicates aerogels as scaffolds for Ag0 nanoparticles used for chemisorption of I2(g). The starting materials for these scaffolds included both Na-Al-Si-O and Al-Si-O aerogels, both synthesized from metal alkoxides. The Ag0 particles are added by soaking the aerogels in AgNO3 followed by drying and flowing under H2/Ar to reduce Ag+ → Ag0. In some cases, samples were soaked in 3-(mercaptopropyl)trimethoxysilane under supercritical CO2 to add –SH tethers to the aerogel surfaces for more effective binding of Ag+. During the Ag+-impregnation steps, for the Na-Al-Si-O aerogels, Na was replaced with Ag, and for the Al-Si-O aerogel, Si was replaced with Ag. The Ag-loading of thiolated versus non-thiolated Na-Al-Si-O aerogels was comparable at ~35 at% whereas the Ag-loading in unthiolated Al-Si-O aerogels was significantly lower at ~ 7 at% after identical treatment. Iodine loadings in both thiolated and unthiolated Ag0-functionalized Na-Al-Si-O aerogels were > 0.5 g g-1 showing almost complete utilization of the Ag through chemisorption to form AgI. Iodine loading in the thiolated Al-Si-O aerogel was 0.31 g g-1. The control of Ag uptake over solution residence time and [AgNO3] demonstrates the ability to customize the Ag-loading in the base sorbent to regulate the capacity of iodine chemisorption. Consolidation experimental results are also presented.

Sorption of caesium and strontium onto calcium silicate hydrate in saline groundwater

International Nuclear Information System (INIS)

Sugiyama, D.; Fujita, T.

2005-01-01

Full text of publication follows: In the concept for radioactive waste disposal in Japan, cement is a potential waste packaging and backfilling material and is expected to provide chemical containment. The sorption of radionuclides onto cement materials, which controls the aqueous concentrations of elements in the pore-water, is a very important parameter when considering the release of radionuclides from the near field of a cementitious radioactive waste repository. Many safety assessment calculations currently assume radionuclide retardation as linear sorption equilibrium and describe it with a distribution ratio (R d value). In this study, the sorption mechanism is discussed by measuring the sorption isotherm of caesium, strontium (10 -5 ∼ 10 -2 mol dm -3 ) and sodium (10 -4 ∼ 10 -1 mol dm -3 ) onto Calcium Silicate Hydrate (C-S-H gel, Ca/Si 0.65 ∼ 1.2) at a liquid:solid ratio of 100:1, to support the assumption. In addition, the competitive sorption between caesium or strontium, and sodium is studied by sorption measurements using a range of sodium chloride concentration to simulate different ionic strengths in saline groundwater. The initial and equilibrated aqueous compositions were measured in the sorption experiments and it was found that caesium, strontium and sodium were sorbed by substitution for Ca in C-S-H phases by examining the mass balance. Based on the experimental results, we propose a modelling approach in which the ion-exchange model is employed and the presence of some calcium sites with different ion-exchange log K values in C-S-H is assumed by considering the composition and the structure of C-S-H. The modelling calculation results predict the measured Rd values well and also describe the competition of sorption of caesium or strontium, and sodium in the experiments. The log K values for sorption of each cation element decreased as Ca/Si ratio of C-S-H gel increased. This agrees with the trend that C-S-H gel is negatively charged at low

Sulfate but not thiosulfate reduces calculated and measured urinary ionized calcium and supersaturation: implications for the treatment of calcium renal stones.

Directory of Open Access Journals (Sweden)

Allen Rodgers

Full Text Available Urinary sulfate (SO4(2- and thiosulfate (S2O3(2- can potentially bind with calcium and decrease kidney stone risk. We modeled the effects of these species on the concentration of ionized calcium (iCa and on supersaturation (SS of calcium oxalate (CaOx and calcium phosphate (CaP, and measured their in vitro effects on iCa and the upper limit of stability (ULM of these salts.Urine data from 4 different types of stone patients were obtained from the Mayo Nephrology Clinic (Model 1. A second data set was obtained from healthy controls and hypercalciuric stone formers in the literature who had been treated with sodium thiosulfate (STS (Model 2. The Joint Expert Speciation System (JESS was used to calculate iCa and SS. In Model 1, these parameters were calculated as a function of sulfate and thiosulfate concentrations. In Model 2, data from pre- and post STS urines were analyzed. ULM and iCa were determined in human urine as a function of sulfate and thiosulfate concentrations.Calculated iCa and SS values for all calcium salts decreased with increasing sulfate concentration. Thiosulfate had no effect on these parameters. In Model 2, calculated iCa and CaOx SS increased after STS treatment, but CaP SS decreased, perhaps due to a decrease in pH after STS treatment. In confirmatory in vitro experiments supplemental sulfate, but not thiosulfate, significantly increased the calcium needed to achieve the ULM of CaP and tended to increase the oxalate needed to reach the ULM of CaOx. Sulfate also significantly decreased iCa in human urine, while thiosulfate had no effect.Increasing urinary sulfate could theoretically reduce CaOx and CaP stone risk. Although STS may reduce CaP stone risk by decreasing urinary pH, it might also paradoxically increase iCa and CaOx SS. As such, STS may not be a viable treatment option for stone disease.

[Effect of sodium carbonate assisted hydrothermal process on heavy metals stabilization in medical waste incinerator fly ash].

Science.gov (United States)

Jin, Jian; Li, Xiao-dong; Chi, Yong; Yan, Jian-hua

2010-04-01

A sodium carbonate assisted hydrothermal process was induced to stabilize the fly ash from medical waste incinerator. The results showed that sodium carbonate assisted hydrothermal process reduced the heavy metals leachability of fly ash, and the heavy metal waste water from the process would not be a secondary pollution. The leachability of heavy metals studied in this paper were Cd 1.97 mg/L, Cr 1.56 mg/L, Cu 2.56 mg/L, Mn 17.30 mg/L, Ni 1.65 mg/L, Pb 1.56 mg/L and Zn 189.00 mg/L, and after hydrothermal process with the optimal experimental condition (Na2CO3/fly ash dosage = 5/20, reaction time = 8 h, L/S ratio = 10/1) the leachability reduced to < 0.02 mg/L for Cd, Cr, Cu, Mn, Ni, Pb, and 0.05 mg/L for Zn, according to GB 5085.3-2007. Meanwhile, the concentrations of heavy metals in effluent after hydrothermal process were less than 0.8 mg/L. The heavy metals leachability and concentration in effluent reduced with prolonged reaction time. Prolonged aging can affect the leachability of metals as solids become more crystalline, and heavy metals transferred inside of crystalline. The mechanism of heavy metal stabilization can be concluded to the co precipitation and adsorption effect of aluminosilicates formation, crystallization and aging process.

[Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

NARCIS (Netherlands)

Jonge, H.J. de; Gans, R.O.; Huls, G.A.

2012-01-01

Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate

Dialysate sodium and sodium gradient in maintenance hemodialysis: a neglected sodium restriction approach?

OpenAIRE

Munoz Mendoza, Jair; Sun, Sumi; Chertow, Glenn M.; Moran, John; Doss, Sheila; Schiller, Brigitte

2011-01-01

Background. A higher sodium gradient (dialysate sodium minus pre-dialysis plasma sodium) during hemodialysis (HD) has been associated with sodium loading; however, its role is not well studied. We hypothesized that a sodium dialysate prescription resulting in a higher sodium gradient is associated with increases in interdialytic weight gain (IDWG), blood pressure (BP) and thirst.

Precipitation diagram of calcium carbonate polymorphs: its construction and significance

International Nuclear Information System (INIS)

Kawano, Jun; Shimobayashi, Norimasa; Miyake, Akira; Kitamura, Masao

2009-01-01

In order to interpret the formation mechanism of calcium carbonate polymorphs, we propose and construct a new 'precipitation diagram', which has two variables: the driving force for nucleation and temperature. The precipitation experiments were carried out by mixing calcium chloride and sodium carbonate aqueous solutions. As a result, a calcite-vaterite co-precipitation zone, a vaterite precipitation zone, a vaterite-aragonite co-precipitation zone and an aragonite precipitation zone can be defined. Theoretical considerations suggest that the steady state nucleation theory can explain well the appearance of these four zones, and the first-order importance of the temperature dependency of surface free energy in the nucleation of aragonite. Furthermore, the addition of an impurity will likely result in the change of these energies, and this precipitation diagram gives a new basis for interpreting the nature of the polymorphs precipitated in both inorganic and biological environments.

The effect of sodium on the mineral balance of plants, using the example of root celery and stalk celery. Part I. The role of sodium and potassium in the process of accumulation and utilization of mineral elements

Directory of Open Access Journals (Sweden)

Urszula Kruszelnicka

2013-12-01

Full Text Available In the years 1977 - 1980, studies were conducted on the effect of sodium used to supplement low (K = 800 mg/5 kg and high (K = 1400 mg/5 kg potassium doses on the content of mineral components, their accumulation in the yield and the percentage of their utilization. The study was carried out on root celery - Apium graveolens L. var. rapaceum (Mill. and stalk celery - Apium graveolens L. var. dulce (Mill.. The results obtained in these experiments point to the following conclusions: it was found that potassium and sodium mutually limit each other's uptake. Sodium was more antagonistic towards the uptake of calcium than was potassium. However, no clearly antagonistic effect of these elements on the uptake of magnesium was determined. The accumulation of potassium and sodium by the experimental plants rose while the percentage of utilization of these elements decreased as their level in the nutrient medium increased. Sodium exerted a more distinct effect on the accumulation and utilization of other mineral elements than did potassium.

Physical, Chemical and Structural Evolution of Zeolite-Containing Waste Forms Produced from Metakaolinite and Calcined Sodium Bearing Waste (HLW and/or LLW)

International Nuclear Information System (INIS)

Grutzeck, Michael W.

2005-01-01

Zeolites are extremely versatile. They can adsorb liquids and gases and serve as cation exchange media. They occur in nature as well cemented deposits. The ancient Romans used blocks of zeolitized tuff as a building material. Using zeolites for the management of radioactive waste is not a new idea, but a process by which the zeolites can be made to act as a cementing agent is. Zeolitic materials are relatively easy to synthesize from a wide range of both natural and man-made substances. The process under study is derived from a well known method in which metakaolin (an impure thermally dehydroxylated kaolinite heated to ∼700 C containing traces of quartz and mica) is mixed with sodium hydroxide (NaOH) and reacted in slurry form (for a day or two) at mildly elevated temperatures. The zeolites form as finely divided powders containing micrometer ((micro)m) sized crystals. However, if the process is changed slightly and only just enough concentrated sodium hydroxide solution is added to the metakaolinite to make a thick crumbly paste and then the paste is compacted and cured under mild hydrothermal conditions (60-200 C), the mixture will form a hard ceramic-like material containing distinct crystalline tectosilicate minerals (zeolites and feldspathoids) imbedded in an X-ray amorphous hydrated sodium aluminosilicate matrix. Due to its lack of porosity and vitreous appearance we have chosen to call this composite a ''hydroceramic''

Association of urinary sodium/creatinine ratio with bone mineral density in postmenopausal women: KNHANES 2008-2011.

Science.gov (United States)

Kim, Sung-Woo; Jeon, Jae-Han; Choi, Yeon-Kyung; Lee, Won-Kee; Hwang, In-Ryang; Kim, Jung-Guk; Lee, In-Kyu; Park, Keun-Gyu

2015-08-01

Accumulating evidence shows that high sodium chloride intake increases urinary calcium excretion and may be a risk factor for osteoporosis. However, the effect of oral sodium chloride intake on bone mineral density (BMD) and risk of osteoporosis has been inadequately researched. The aim of the present study was to determine whether urinary sodium excretion (reflecting oral sodium chloride intake) associates with BMD and prevalence of osteoporosis in postmenopausal women. This cross-sectional study involved a nationally representative sample consisting of 2,779 postmenopausal women who participated in the Korea National Health and Nutritional Examination Surveys in 2008-2011. The association of urinary sodium/creatinine ratio with BMD and other osteoporosis risk factors was assessed. In addition, the prevalence of osteoporosis was assessed in four groups with different urinary sodium/creatinine ratios. Participants with osteoporosis had significantly higher urinary sodium/creatinine ratios than the participants without osteoporosis. After adjusting for multiple confounding factors, urinary sodium/creatinine ratio correlated inversely with lumbar spine BMD (P = 0.001). Similarly, when participants were divided into quartile groups according to urinary sodium/creatinine ratio, the average BMD dropped as the urinary sodium/creatinine ratio increased. Multiple logistic regression analysis revealed that compared to quartile 1, quartile 4 had a significantly increased prevalence of lumbar spine osteoporosis (odds ratios 1.346, P for trend = 0.044). High urinary sodium excretion was significantly associated with low BMD and high prevalence of osteoporosis in lumbar spine. These results suggest that high sodium chloride intake decreases lumbar spine BMD and increases the risk of osteoporosis in postmenopausal women.

Preventing the settling of salts of calcium and magnesium in oil production on the Boka oil field

Energy Technology Data Exchange (ETDEWEB)

Katincic, Z

1972-01-01

The results are given of laboratory and plant tests of the influence of sodium hexametaphosphate on the prevention of separation and settling of the salts of calcium and magnesium in the pipelines of the Boka oil field. All the former methods of fighting the salts consisted in dissolving the sediments of salt and paraffin in pipelines and the obligatory holding up of production, which required a loss in production in addition to material costs. By using the sodium hexametaphosphate, the settling of Ca and Mg salts in pipelines was prevented without holding up the production at considerably smaller cost.

Bond strength and interfacial morphology of orthodontic brackets bonded to eroded enamel treated with calcium silicate-sodium phosphate salts or resin infiltration.

Science.gov (United States)

Costenoble, Aline; Vennat, Elsa; Attal, Jean-Pierre; Dursun, Elisabeth

2016-11-01

 To investigate the shear bond strength (SBS) of orthodontic brackets bonded to eroded enamel treated with preventive approaches and to examine the enamel/bracket interfaces.  Ninety-one brackets were bonded to seven groups of enamel samples: sound; eroded; eroded+treated with calcium silicate-sodium phosphate salts (CSP); eroded+infiltrated by ICON ® ; eroded+infiltrated by ICON ® and brackets bonded with 1-month delay; eroded+infiltrated by an experimental resin; and eroded+infiltrated by an experimental resin and brackets bonded with 1-month delay. For each group, 12 samples were tested in SBS and bond failure was assessed with the adhesive remnant index (ARI); one sample was examined using scanning electron microscopy (SEM).  Samples treated with CSP or infiltration showed no significant differences in SBS values with sound samples. Infiltrated samples followed by a delayed bonding showed lower SBS values. All of the values remained acceptable. The ARI scores were significantly higher for sound enamel, eroded, and treated with CSP groups than for all infiltrated samples. SEM examinations corroborated the findings.  Using CSP or resin infiltration before orthodontic bonding does not jeopardize the bonding quality. The orthodontic bonding should be performed shortly after the resin infiltration.

Nutrição de mudas de açaizeiro sob relações cálcio:potássio:sódio em solução nutritiva Nutrition of açai seedlings (Euterpe oleracea Mart. under different ratios of calcium:potassium: sodium in nutrient solution

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Humberto Umbelino de Sousa

2004-02-01

Full Text Available Objetivando-se estudar diferentes relações entre os cátions cálcio, potássio e sódio na produção de matéria seca e acúmulo de macronutrientes em mudas de açaizeiro (Euterpe oleracea Mart., realizou-se um experimento em casa-de-vegetação no Departamento de Ciência do Solo da UFLA. Utilizou-se o delineamento estatístico em blocos casualisados com nove tratamentos em quatro repetições. Os tratamentos foram constituídos por nove relações cálcio: potássio: sódio (4:2:1, 3:3:1, 2:4:1, 1:5:1, 5:1:1, 4:1:2, 6:0:1; 0:6:1, e 4:2:0 em solução nutritiva. A unidade experimental constituiu-se de um vaso com capacidade para três litros de solução, contendo duas plantas. Avaliaram-se as seguintes características: produção de matéria seca e o acúmulo dos macronutrientes fósforo, cálcio, potássio, magnésio e enxofre na matéria seca da planta. A relação cálcio:potássio:sódio influenciou todas as características avaliadas; as soluções contendo cálcio, potássio e sódio nas relações 4:2:1 e 3:3:1 resultaram no desenvolvimento de mudas com maior produção de matéria seca e maior acúmulo de nutrientes.Aiming to evaluate the effects of different ratios of calcium, potassium and sodium cations on the mineral nutrition of açai seedlings (Euterpe oleracea Mart., a greenhouse experiment was carried out in the Soil Science Department at the Federal University of Lavras-UFLA. The randomized block design, with nine treatments and four replications, was used. The treatments were nine ratios of calcium, potassium and sodium (4:2:1, 3:3:1, 2:4:1, 1:5:1, 5:1:1, 4:1:2, 6:0:1; 0:6:1, e 4:2:0 in the nutrient solution. The experimental unit was a plastic pot with three liters of solution, containing two plants. The total dry matter and nutrient accumulation were evaluated. The relationship calcium:potassium:sodium influenced all the appraised characteristics, and the solutions containing calcium, potassium and sodium in the ratios

Characterization of Samples from the Effluent Treatment Facility Evaporator Waste Concentrate Tank

Energy Technology Data Exchange (ETDEWEB)

Wilmarth, W.R. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1998-01-31

During October 1997, the ETF Evaporator Waste Concentrate Tank No. 2 was discovered to contain a significant accumulation of solid deposits. SRTC performed destructive and nondestructive examination of solid samples from the tank. The results of these tests indicate that the solids contain mixtures of sodium oxalate (65 percent), the sulfide enclathrated sodium aluminosilicate (30 percent), and iron oxide (5 percent).

Characterization of Samples from the Effluent Treatment Facility Evaporator Waste Concentrate Tank

International Nuclear Information System (INIS)

Wilmarth, W.R.

1998-01-01

During October 1997, the ETF Evaporator Waste Concentrate Tank No. 2 was discovered to contain a significant accumulation of solid deposits. SRTC performed destructive and nondestructive examination of solid samples from the tank. The results of these tests indicate that the solids contain mixtures of sodium oxalate (65 percent), the sulfide enclathrated sodium aluminosilicate (30 percent), and iron oxide (5 percent)

Kinetic and equilibrium properties of regulatory Ca(2+)-binding domains in sodium-calcium exchangers 2 and 3.

Science.gov (United States)

Tal, Inbal; Kozlovsky, Tom; Brisker, Dafna; Giladi, Moshe; Khananshvili, Daniel

2016-04-01

In mammals, three sodium-calcium exchanger (NCX) protein isoforms (NCX1, NCX2, and NCX3) mediate Ca(2+) fluxes across the membrane to maintain cellular Ca(2+) homeostasis. NCX isoforms and their splice variants are expressed in a tissue-specific manner to meet physiological demands. NCX1 is ubiquitously expressed, NCX2 is expressed in the brain and spinal cord, and NCX3 is expressed in the brain and skeletal muscle. Eukaryotic NCXs contain two cytosolic regulatory Ca(2+)-binding domains, CBD1 and CBD2, which form a two-domain tandem (CBD12) through a short linker. Ca(2+) binding to the CBDs underlies allosteric regulation of NCX. Previous structural and functional studies in NCX1 have shown that the CBDs synergistically interact, where their interactions are modulated in a splice variant-specific manner by splicing segment at CBD2. Here, we analyze the equilibrium and kinetic properties of Ca(2+) binding to purified preparations of CBD1, CBD2, and CBD12 from NCX2 and from NCX3 splice variants. We show that CBD1 interacts with CBD2 in the context of the CBD12 tandem in all NCX isoforms, where these interactions specifically modulate Ca(2+) sensing at the primary sensor of CBD1 to meet the physiological requirements. For example, the rate-limiting slow dissociation of "occluded" Ca(2+) from the primary allosteric sensor of variants expressed in skeletal muscle is ∼10-fold slower than that of variants expressed in the brain. Notably, these kinetic differences between NCX variants occur while maintaining a similar Ca(2+) affinity of the primary sensor, since the resting [Ca(2+)]i levels are similar among different cell types. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

2010-04-01

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

Sodium pump activity and calcium relaxation in vascular smooth muscle of deoxycorticosterone acetate-salt rats

International Nuclear Information System (INIS)

Soltis, E.E.; Field, F.P.

1986-01-01

The Na + -K + pump activity was determined in femoral arterial smooth muscle from deoxycorticosterone acetate (DOCA)-salt hypertensive rats using potassium relaxation and ouabain-sensitive 86 Rb uptake as indices. The membrane-stabilizing effect of calcium and its relation to Na + -K + pump activity also were examined. Femoral arteries from DOCA-salt rats exhibited a greater relaxation in response to potassium addition after contraction with norepinephrine in a low potassium (0.6 mM) Krebs solution. The concentration of potassium required to produce a 50% relaxation was significantly less in DOCA-salt rats. Ouabain-sensitive 86 Rb uptake was significantly greater at 3, 10, and 20 minutes of 86 Rb incubation in femoral arteries from DOCA-salt rats. Linear regression analysis revealed a significant correlation between the uptake of 86 Rb and time of incubation in both control and DOCA-salt rats. A significant difference in the slopes of the regression lines showed that the rate of uptake was greater in DOCA-salt rats. No difference was observed in ouabain-insensitive 86 Rb uptake. A dose-dependent relaxation in response to increasing concentrations of calcium following contraction to norepinephrine was observed in femoral arteries from control and DOCA-salt rats. The relaxation was directly dependent on the level of extracellular potassium and was blocked by ouabain. Femoral arteries from DOCA-salt rats relaxed to a significantly greater extent in response to calcium at each level of potassium when compared with controls. These results provide further evidence for an increase in Na + -K + pump activity in vascular smooth muscle from DOCA-salt hypertensive rats

Enhanced oxidation resistance of carbon fiber reinforced lithium aluminosilicate composites by boron doping

International Nuclear Information System (INIS)

Xia, Long; Jin, Feng; Zhang, Tao; Hu, Xueting; Wu, Songsong; Wen, Guangwu

2015-01-01

Highlights: • C f /LAS composites exhibit enhanced oxidation resistance by boron doping. • Boron doping is beneficial to the improvement of graphitization degree of carbon fibers. • Graphitization of carbon fibers together with the decrease of viscosity of LAS matrix is responsible to the enhancement of oxidation resistance of C f /LAS composites. - Abstract: Carbon fiber reinforced lithium aluminosilicate matrix composites (C f /LAS) modified with boron doping were fabricated and oxidized for 1 h in static air. Weight loss, residual strength and microstructure were analyzed. The results indicate that boron doping has a remarkable effect on improving the oxidation resistance for C f /LAS. The synergism of low viscosity of LAS matrix at high temperature and formation of graphite crystals on the surface of carbon fibers, is responsible for excellent oxidation resistance of the boron doped C f /LAS.

Low Calcium Intake in Midpregnancy Is Associated with Hypertension Development within 10 Years after Pregnancy: The Norwegian Mother and Child Cohort Study.

Science.gov (United States)

Egeland, Grace M; Skurtveit, Svetlana; Sakshaug, Solveig; Daltveit, Anne Kjersti; Vikse, Bjørn E; Haugen, Margaretha

2017-09-01

Background: Low dietary calcium intake may be a risk factor for hypertension, but studies conflict. Objective: We evaluated the ability to predict hypertension within 10 y after delivery based on calcium intake during midpregnancy. Methods: The Norwegian Mother and Child Cohort Study of women delivering in 2004-2009 was linked to the Norwegian Prescription Database (2004-2013) to ascertain antihypertensive medication usage >90 d after delivery. Women with hypertension before pregnancy were excluded, leaving 60,027 mothers for analyses. Age and energy-adjusted cubic splines evaluated dose-response curves, and Cox proportional hazard analyses evaluated HR and 95% CIs by calcium quartiles adjusting for 7 covariates. Analyses were stratified by gestational hypertension and by sodium-to-potassium intake ratio (pregnancy, and a mean follow-up duration of 7.1 ± 1.6 y. Cubic spline graphs identified a threshold effect of low calcium intake only within the range of dietary inadequacy related to increased risk. The lowest calcium quartile (≤738 mg/d; median: 588 mg/d), relative to the highest quartile (≥1254 mg/d), had an HR for hypertension of 1.34 (95% CI: 1.05, 1.70) among women who were normotensive during pregnancy, and an HR of 1.62 (95% CI: 1.14, 2.35) among women who had gestational hypertension, after adjusting for covariates. Women with gestational hypertension, who were in the lowest quartile of calcium intake, and who had a high sodium-to-potassium intake ratio had a risk of hypertension more than double that of their counterparts with a calcium intake in the highest quartile. Results were attenuated by adjusting for covariates (HR: 1.92; 95% CI: 1.09, 3.39). Conclusions: The results suggest that low dietary calcium intake may be a risk factor or risk marker for the development of hypertension, particularly for women with a history of gestational hypertension. © 2017 American Society for Nutrition.

Determination of percent calcium carbonate in calcium chromate

International Nuclear Information System (INIS)

Middleton, H.W.

1979-01-01

The precision, accuracy and reliability of the macro-combustion method is superior to the Knorr alkalimetric method, and it is faster. It also significantly reduces the calcium chromate waste accrual problem. The macro-combustion method has been adopted as the official method for determination of percent calcium carbonate in thermal battery grade anhydrous calcium chromate and percent calcium carbonate in quicklime used in the production of calcium chromate. The apparatus and procedure can be used to measure the percent carbonate in inorganic materials other than calcium chromate. With simple modifications in the basic apparatus and procedure, the percent carbon and hydrogen can be measured in many organic material, including polymers and polymeric formulations. 5 figures, 5 tables

Patterns in the Parathyroid Response to Sodium Bicarbonate Infusion Test in Healthy Volunteers

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Theodossis S. Papavramidis

2014-01-01

Full Text Available Background. The sodium bicarbonate infusion test evaluates the function of the parathyroid glands. The present study aims to evaluate the range of parathyroid response in healthy individuals and the potential influence of various factors. Methods. Fifty healthy volunteers were subjected to the test. Levels of vitamin D, calcium, albumin, and PTH were measured before infusion. PTH was measured at 3, 5, 10, 30, and 60 minutes after infusion. Results. A curve describing the response of parathyroids to the test was drawn. Twenty percent of the subjects had blunted PTH response. No significant difference was observed between normal and blunted responders concerning age, BMI, baseline PTH, or calcium levels. Nonetheless, there was a significant difference in vitamin D levels (P=0.024. Interpretation. The test is easy to perform and may be used for everyday screening. It has to be clarified whether our observations are, at least partly, produced due to the presence of individuals with a constitutively blunted response or if low levels of vitamin D decrease the ability of the parathyroids to respond. Whichever the case, PTH response of normal individuals to sodium bicarbonate infusion test is more varied than previously thought and vitamin D levels influence it.

Voltage-gated sodium channels in taste bud cells

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Williams Mark E

2009-03-01

Full Text Available Abstract Background Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. Results We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. Conclusion SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.

Voltage-gated sodium channels in taste bud cells.

Science.gov (United States)

Gao, Na; Lu, Min; Echeverri, Fernando; Laita, Bianca; Kalabat, Dalia; Williams, Mark E; Hevezi, Peter; Zlotnik, Albert; Moyer, Bryan D

2009-03-12

Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown. We describe the molecular and histological expression profiles of cation channels involved in electrical signal transmission from apical to basolateral membrane domains. TRPM5 was positioned immediately beneath tight junctions to receive calcium signals originating from sweet, bitter, and umami receptor activation, while PKD2L1 was positioned at the taste pore. Using mouse taste bud and lingual epithelial cells collected by laser capture microdissection, SCN2A, SCN3A, and SCN9A voltage-gated sodium channel transcripts were expressed in taste tissue. SCN2A, SCN3A, and SCN9A were expressed beneath tight junctions in subsets of taste cells. SCN3A and SCN9A were expressed in TRPM5 cells, while SCN2A was expressed in TRPM5 and PKD2L1 cells. HCN4, a gene previously implicated in sour taste, was expressed in PKD2L1 cells and localized to cell processes beneath the taste pore. SCN2A, SCN3A and SCN9A voltage-gated sodium channels are positioned to sense initial depolarizing signals stemming from taste receptor activation and initiate taste cell action potentials. SCN2A, SCN3A and SCN9A gene products likely account for the tetrodotoxin-sensitive sodium currents in taste receptor cells.

Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

International Nuclear Information System (INIS)

Yu Jiaguo; Tang Hua; Cheng Bei; Zhao Xiujian

2004-01-01

Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca 2+ ]/[C 2 O 4 2- ] ratio and concentration of PSMA and CaC 2 O 4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis

Effectiveness of Chlorinated Water, Sodium Hypochlorite, Sodium ...

African Journals Online (AJOL)

This study evaluated the efficacy of chlorinated water, sodium hypochlorite solution, sodium chloride solution and sterile distilled water in eliminating pathogenic bacteria on the surfaces of raw vegetables. Lettuce vegetables were dipped in different concentrations of chlorinated water, sodium hypochlorite solution, sodium ...

Investigation of organic desulfurization additives affecting the calcium sulfate crystals formation

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Lv Lina

2017-01-01

Full Text Available In the study, the optimal experimental conditions for gypsum crystals formation were 323 K, 300 rpm stirring speed. The major impurities of Mg2+, Al3+ and Fe3+ were found to inhibit calcium sulfate crystals formation. Fe3+ caused the strongest inhibition, followed by Mg2+ and Al3+. The influence of desulfurization additives on the gypsum crystals formation was explored with the properties of moisture content, particle size distribution and crystal morphology. The organic desulfurization additives of adipic acid, citric acid, sodium citrate and benzoic acid were investigated. Citric acid and sodium citrate were found to improve the quality of gypsum. Moisture contents were reduced by more than 50%, gypsum particle sizes were respectively enlarged by 9.1 and 22.8%, induction time extended from 4.3 (blank to 5.3 and 7.8 min, and crystal morphology trended to be thicker.

Computational model based approach to analysis ventricular arrhythmias: Effects of dysfunction calcium channels

Science.gov (United States)

Gulothungan, G.; Malathi, R.

2018-04-01

Disturbed sodium (Na+) and calcium (Ca2+) handling is known to be a major predisposing factor for life-threatening cardiac arrhythmias. Cardiac contractility in ventricular tissue is prominent by Ca2+ channels like voltage dependent Ca2+ channels, sodium-calcium exchanger (Na+-Ca2+x) and sacroplasmicrecticulum (SR) Ca2+ pump and leakage channels. Experimental and clinical possibilities for studying cardiac arrhythmias in human ventricular myocardium are very limited. Therefore, the use of alternative methods such as computer simulations is of great importance. Our aim of this article is to study the impact on action potential (AP) generation and propagation in single ventricular myocyte and ventricular tissue under different dysfunction Ca2+ channels condition. In enhanced activity of Na+-Ca2+x, single myocyte produces AP duration (APD90) and APD50 is significantly smaller (266 ms and 235 ms). Its Na+-Ca2+x current at depolarization is increases 60% from its normal level and repolarization current goes more negative (nonfailing= -0.28 pA/pF and failing= -0.47 pA/pF). Similarly, same enhanced activity of Na+-Ca2+x in 10 mm region of ventricular sheet, raises the plateau potential abruptly, which ultimately affects the diastolic repolarization. Compare with normal ventricular sheet region of 10 mm, 10% of ventricular sheet resting state is reduces and ventricular sheet at time 250 ms is goes to resting state very early. In hypertrophy condition, single myocyte produces APD90 and APD50 is worthy of attention smaller (232 mS and 198 ms). Its sodium-potassium (Na+-K+) pump current is 75% reduces from its control conditions (0.13 pA/pF). Hypertrophy condition, 50% of ventricular sheet is reduces to minimum plateau potential state, that starts the repolarization process very early and reduces the APD. In a single failing SR Ca2+ channels myocyte, recovery of Ca2+ concentration level in SR reduces upto 15% from its control myocytes. At time 290 ms, 70% of ventricular sheet

Electro-optical parameters of bond polarizability model for aluminosilicates.

Science.gov (United States)

Smirnov, Konstantin S; Bougeard, Daniel; Tandon, Poonam

2006-04-06

Electro-optical parameters (EOPs) of bond polarizability model (BPM) for aluminosilicate structures were derived from quantum-chemical DFT calculations of molecular models. The tensor of molecular polarizability and the derivatives of the tensor with respect to the bond length are well reproduced with the BPM, and the EOPs obtained are in a fair agreement with available experimental data. The parameters derived were found to be transferable to larger molecules. This finding suggests that the procedure used can be applied to systems with partially ionic chemical bonds. The transferability of the parameters to periodic systems was tested in molecular dynamics simulation of the polarized Raman spectra of alpha-quartz. It appeared that the molecular Si-O bond EOPs failed to reproduce the intensity of peaks in the spectra. This limitation is due to large values of the longitudinal components of the bond polarizability and its derivative found in the molecular calculations as compared to those obtained from periodic DFT calculations of crystalline silica polymorphs by Umari et al. (Phys. Rev. B 2001, 63, 094305). It is supposed that the electric field of the solid is responsible for the difference of the parameters. Nevertheless, the EOPs obtained can be used as an initial set of parameters for calculations of polarizability related characteristics of relevant systems in the framework of BPM.

Evolution of the Calcium Paradigm: The Relation between Vitamin D, Serum Calcium and Calcium Absorption

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Borje E. Christopher Nordin

2010-09-01

Full Text Available Osteoporosis is the index disease for calcium deficiency, just as rickets/osteomalacia is the index disease for vitamin D deficiency, but there is considerable overlap between them. The common explanation for this overlap is that hypovitaminosis D causes malabsorption of calcium which then causes secondary hyperparathyroidism and is effectively the same thing as calcium deficiency. This paradigm is incorrect. Hypovitaminosis D causes secondary hyperparathyroidism at serum calcidiol levels lower than 60 nmol/L long before it causes malabsorption of calcium because serum calcitriol (which controls calcium absorption is maintained until serum calcidiol falls below 20 nmol/L. This secondary hyperparathyroidism, probably due to loss of a “calcaemic” action of vitamin D on bone first described in 1957, destroys bone and explains why vitamin D insufficiency is a risk factor for osteoporosis. Vitamin D thus plays a central role in the maintenance of the serum (ionised calcium, which is more important to the organism than the preservation of the skeleton. Bone is sacrificed when absorbed dietary calcium does not match excretion through the skin, kidneys and bowel which is why calcium deficiency causes osteoporosis in experimental animals and, by implication, in humans.

Calcium absorption

International Nuclear Information System (INIS)

Carlmark, B.; Reizenstein, P.; Dudley, R.A.

1976-01-01

The methods most commonly used to measure the absorption and retention of orally administered calcium are reviewed. Nearly all make use of calcium radioisotopes. The magnitude of calcium absorption and retention depends upon the chemical form and amount of calcium administered, and the clinical and nutritional status of the subject; these influences are briefly surveyed. (author)

Effect of sodium fluoride in maternal and offspring rats and its amelioration

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Sneha Panchal

2014-03-01

Full Text Available High fluoride content is known to cause dental and skeletal abnormalities. In addition, present review indicates that sodium fluoride consumption caused increased number of r=esorptions and dead foetuses. Various skeletal anomalies such as wavy ribs, presence of 14th ribs, lacking 6th sternebrae and incompete ossification of skull occur. All these changes could be due to oxidative stress caused by fluoride consumption. Fluoride-induced changes could be successfully ameliorated by cotreatment with vitamins and calcium.

Radioisotope 45Ca labeling four calcium chemical compounds and tracing calcium bioavailability

International Nuclear Information System (INIS)

Zheng Hui; Zhen Rong; Niu Huisheng; Li Huaifen

2004-01-01

Objective: To build up a new method of the radioisotope 45 Ca labeling four calcium chemical compounds, observe and tracing bioavailability change of calcium labeled with radioisotope 45 Ca. Methods: The calcium gluconate (Ca-Glu), calcium citrate (Ca-Cit), calcium carbonate (Ca-Car) and calcium L-threonate (Ca-Thr)were labeled by radioisotope 45 Ca. Four calcium chemical compounds of 45 Ca labeling were used of calcium content 200 mg/kg in the rats and measure the absorption content and bioavailability of calcium in tissue of heart, lever spleen, stomach, kidney, brain, intestine, whole blood, urine, faeces. Results: 1) Radioisotope 45 Ca labeling calcium chemical compound has high radio intensity, more steady standard curve and recover rate. 2) The absorption of organic calcium chemical compounds is higher than the inorganic calcium chemical compound in the study of calcium bioavailability. Conclusion: The method of tracing with radioisotope 45 Ca labeling calcium chemical compounds has the characteristic of the sensitive, objective, accurate and steady in the study of calcium bioavailability

The impact of calcium assay change on a local adjusted calcium equation.

Science.gov (United States)

Davies, Sarah L; Hill, Charlotte; Bailey, Lisa M; Davison, Andrew S; Milan, Anna M

2016-03-01

Deriving and validating local adjusted calcium equations is important for ensuring appropriate calcium status classification. We investigated the impact on our local adjusted calcium equation of a change in calcium method by the manufacturer from cresolphthalein complexone to NM-BAPTA. Calcium and albumin results from general practice requests were extracted from the Laboratory Information Management system for a three-month period. Results for which there was evidence of disturbance in calcium homeostasis were excluded leaving 13,482 sets of results for analysis. The adjusted calcium equation was derived following least squares regression analysis of total calcium on albumin and normalized to the mean calcium concentration of the data-set. The revised equation (NM-BAPTA calcium method) was compared with the previous equation (cresolphthalein complexone calcium method). The switch in calcium assay resulted in a small change in the adjusted calcium equation but was not considered to be clinically significant. The calcium reference interval differed from that proposed by Pathology Harmony in the UK. Local adjusted calcium equations should be re-assessed following changes in the calcium method. A locally derived reference interval may differ from the consensus harmonized reference interval. © The Author(s) 2015.

Effect of silica fume on the characterization of the geopolymer materials

Science.gov (United States)

Khater, Hisham M.

2013-12-01

The influence of silica fume (SF) addition on properties of geopolymer materials produced from alkaline activation of alumino-silicates metakaolin and waste concrete produced from demolition works has been studied through the measurement of compressive strength, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) analysis. Alumino-silicate materials are coarse aggregate included waste concrete and fired kaolin (metakaolin) at 800°C for 3 h, both passing a sieve of 90 μm. Mix specimens containing silica fume were prepared at water/binder ratios in a range of 0.30 under water curing. The used activators are an equal mix of sodium hydroxide and silicate in the ratio of 3:3 wt.%. The control geopolymer mix is composed of metakaolin and waste concrete in an equal mix (50:50, wt.%). Waste concrete was partially replaced by silica fume by 1 to 10 wt.%. The results indicated that compressive strengths of geopolymer mixes incorporating SF increased up to 7% substitution and then decreased up to 10% but still higher than that of the control mix. Results indicated that compressive strengths of geopolymer mixes incorporating SF increases up to 7% substitution and then decreases up to 10% but still higher than the control mix, where 7% SF-digested calcium hydroxide (CH) crystals, decreased the orientation of CH crystals, reduced the crystal size of CH gathered at the interface, and improved the interface more effectively.

Calcium oxalate druses affect leaf optical properties in selenium-treated Fagopyrum tataricum.

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Golob, Aleksandra; Stibilj, Vekoslava; Nečemer, Marijan; Kump, Peter; Kreft, Ivan; Hočevar, Anja; Gaberščik, Alenka; Germ, Mateja

2018-03-01

Plants of the genus Fagopyrum contain high levels of crystalline calcium oxalate (CaOx) deposits, or druses, that can affect the leaf optical properties. As selenium has been shown to modify the uptake and accumulation of metabolically important elements such as calcium, we hypothesised that the numbers of druses can be altered by selenium treatment, and this would affect the leaf optical properties. Tartary buckwheat (Fagopyrum tataricum Gaertn.) was grown outdoors in an experimental field. At the beginning of flowering, plants were foliarly sprayed with sodium selenate solution at 10 mg selenium L -1 or only with water. Plant morphological, biochemical, physiological and optical properties were examined, along with leaf elemental composition and content. Se spraying did not affect leaf biochemical and functional properties. However, it increased leaf thickness and the contents of Se in the leaves, and decreased the density of calcium oxalate druses in the leaves. Except Se content, Se spraying did not affect contents of other elements in leaves, including total calcium per dry mass of leaf tissue. Redundancy analysis showed that of all parameters tested, only the calcium oxalate druses parameters were significant in explaining the variability of the leaf reflectance and transmittance spectra. The density of CaOx druses positively correlated with the reflectance in the blue, green, yellow and UV-B regions of the spectrum, while the area of CaOx druses per mm 2 of leaf transection area positively correlated with the transmittance in the green and yellow regions of the spectrum. Copyright © 2018 Elsevier B.V. All rights reserved.

Calcium currents in a fast-twitch skeletal muscle of the rat.

Science.gov (United States)

Donaldson, P L; Beam, K G

1983-10-01

Slow ionic currents were measured in the rat omohyoid muscle with the three-microelectrode voltage-clamp technique. Sodium and delayed rectifier potassium currents were blocked pharmacologically. Under these conditions, depolarizing test pulses elicited an early outward current, followed by a transient slow inward current, followed in turn by a late outward current. The early outward current appeared to be a residual delayed rectifier current. The slow inward current was identified as a calcium current on the basis that (a) its magnitude depended on extracellular calcium concentration, (b) it was blocked by the addition of the divalent cations cadmium or nickel, and reduced in magnitude by the addition of manganese or cobalt, and (c) barium was able to replace calcium as an inward current carrier. The threshold potential for inward calcium current was around -20 mV in 10mM extracellular calcium and about -35 mV in 2 mM calcium. Currents were net inward over part of their time course for potentials up to at least +30 mV. At temperatures of 20-26 degrees C, the peak inward current (at approximately 0 mV) was 139 +/- 14 microA/cm2 (mean +/- SD), increasing to 226 +/- 28 microA/cm2 at temperatures of 27-37 degrees C. The late outward current exhibited considerable fiber-to-fiber variability. In some fibers it was primarily a time-independent, nonlinear leakage current. In other fibers it was primarily a time-independent, nonlinear leakage current. In other fibers it appeared to be the sum of both leak and a slowly activated outward current. The rate of activation of inward calcium current was strongly temperature dependent. For example, in a representative fiber, the time-to-peak inward current for a +10-mV test pulse decreased from approximately 250 ms at 20 degrees C to 100 ms at 30 degrees C. At 37 degrees C, the time-to-peak current was typically approximately 25 ms. The earliest phase of activation was difficult to quantify because the ionic current was partially

Nitrite-cured color and phosphate-mediated water binding of pork muscle proteins as affected by calcium in the curing solution.

Science.gov (United States)

Zhao, Jing; Xiong, Youling L

2012-07-01

Calcium is a mineral naturally present in water and may be included into meat products during processing thereby influencing meat quality. Phosphates improve myofibril swelling and meat water-holding capacity (WHC) but can be sensitive to calcium precipitation. In this study, pork shoulder meat was used to investigate the impact of calcium at 0, 250, and 500 ppm and phosphate type [sodium pyrophosphate (PP), tripolyphosphate (TPP), and hexametaphopshate (HMP)] at 10 mM on nitrite-cured protein extract color at various pH levels (5.5, 6.0, and 6.5) and crude myofibril WHC at pH 6.0. Neither calcium nor phosphates present in the curing brines significantly affected the cured color. Increasing the pH tended to promote the formation of metmyoglobin instead of nitrosylmyoglobin. The ability of PP to enhance myofibril WHC was hampered (P meat products. Although not affecting nitrite-cured color, calcium hampers the efficacy of phosphates to promote water binding by muscle proteins, underscoring the importance of water quality for brine-enhanced meat products. © 2012 Institute of Food Technologists®

CRACK2 - Modelling calcium carbonate deposition from bicarbonate solution in cracks in concrete

International Nuclear Information System (INIS)

Brodersen, K.

2003-03-01

The numerical CRACK2 model simulates precipitation of calcite from calcium bicarbonate solution (e.g. groundwater) passing through cracks in concrete or other cementitious materials. A summary of experimental work is followed by a detailed description of the model. Hydroxyl ions are transported by diffusion in pore systems in columns of cementitious materials. The hydroxyl is precipitating calcite from a flow of bicarbonate solution in a crack connecting the ends of a row of such columns. The cementitious material is simulated as calcium hydroxide mixed with inert material but with sodium hydroxide dissolved in the pore solution. Diffusive migration of cesium as radioactive isotope is also considered. Electrical interaction of the migrating ions is taken into account. Example calculations demonstrate effects of parameter variations on distribution of precipitated calcite in the crack and on the composition of the outflowing solution, which can be compared directly with experimental results. Leaching behavior of sodium can be used to tune the model to experimental observations. The calcite is mostly precipitated on top of the original crack surface and may under certain circumstances fill the crack. The produced thin layers of low porosity calcite act as a diffusion barrier limiting contact between cement and solution. Pore closure mechanisms in such layers are discussed. Implications for safety assessment of radioactive waste disposal are shortly mentioned. The model is also relevant for conventional uses of concrete. (au)

Calcium supplements

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

Properties of dry masonry mixtures based on hollow aluminosilicate microspheres

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Semenov Vyacheslav

2017-01-01

Full Text Available At present, there is a steady increase in the volume of housing construction in the Russian Federation. The modern trends in the field of energy and resource saving determine the need of the use of efficient building materials that ensure the safety, comfort and minimum cost of housing construction. Among the materials, often used for erecting of fencing structures, it is possible to note effective small-piece elements (ceramic and light-weight concrete units, etc.. To ensure the solidity of such structures, it is necessary to use the masonry mortars whose properties correspond to those of the main wall material. The existing dry mixes for obtaining of such mortars are expensive and often do not meet the minimum physical-and-mechanical and exploitation requirements. The solution of this problem is the usage of the hollow ceramics (aluminosilicate microspheres as a filler for such mixes. The article presents the results of studies of the main physical-and-mechanical and exploitation characteristics of dry masonry mixes with hollow ceramics microspheres modified with various chemical additives. The effect of the compounding factors on the average density and strength of dry masonry mixes was studied. The compositions have been optimized by the methods of mathematical planning.

Judd-Ofelt Analysis of Dy3+-Activated Aluminosilicate Glasses Prepared by Sol-Gel Method

Science.gov (United States)

Sengthong, Buonyavong; Van Tuyen, Ho; An, Nguyen Thi Thai; Van Do, Phan; Hai, Nguyen Thi Quy; Chau, Pham Thi Minh; Quang, Vu Xuan

2018-04-01

Aluminosilicate (AS) glasses doped with different Dy3+ concentrations were synthesized via sol-gel method. Absorption, photoluminescence spectra and lifetime of this material have been studied. From analytical results of absorption spectra, the Judd-Ofelt (JO) parameters of prepared samples have been determined. These JO parameters combined with photoluminescence spectra have been used to evaluate transition probabilities ( A R), branching ratios ( β) and the calculated oscillator strengths of AS:Dy3+ glasses. The radiative branching ratio of 4F9/2 → 6H13/2 transition has a minimum value at 62.2% for β R which predicts that this transition in AS:Dy3+ glasses can give rise to lasing action. JO parameters show that the Ω2 increases with the increasing of Dy3+ ion concentration due to the increased polarizability of the average coordination medium and decreased average symmetry.

Flicking technique for microencapsulation of cells in calcium alginate leading to the microtissue formation.

Science.gov (United States)

Wong, Soon Chuan; Soon, Chin Fhong; Leong, Wai Yean; Tee, Kian Sek

2016-01-01

Microbeads have wide applications in biomedical engineering field that include drug delivery, encapsulation of biomolecules, tissue padding and tissue regeneration. In this paper, we report a simple, yet efficient, flicking technique to produce microcapsules of calcium alginate at a narrow distribution of size. The system consists of an infusion pump and a customised flicker that taps the syringe needle for dispersing microcapsules of sodium alginate that polymerised in the calcium chloride solution. The flow rate of the syringe pump and the velocity of the flicker were studied to achieve a well controlled and tunable size distribution of microbeads ranging from 200 to 400 μm. At a flow rate of 4 μl/min and flicking rate of 80 rpm, a narrow size distribution of microbeads were produced. Via this technique, HaCaT cells were encapsulated in calcium alginate microbeads that grown into microtissues with a size ranging from 100 to 300 μm after two weeks of culture. These microtissues could be potentially useful for pharmacological application.

Calcium waves.

Science.gov (United States)

Jaffe, Lionel F

2008-04-12

Waves through living systems are best characterized by their speeds at 20 degrees C. These speeds vary from those of calcium action potentials to those of ultraslow ones which move at 1-10 and/or 10-20 nm s(-1). All such waves are known or inferred to be calcium waves. The two classes of calcium waves which include ones with important morphogenetic effects are slow waves that move at 0.2-2 microm s(-1) and ultraslow ones. Both may be propagated by cycles in which the entry of calcium through the plasma membrane induces subsurface contraction. This contraction opens nearby stretch-sensitive calcium channels. Calcium entry through these channels propagates the calcium wave. Many slow waves are seen as waves of indentation. Some are considered to act via cellular peristalsis; for example, those which seem to drive the germ plasm to the vegetal pole of the Xenopus egg. Other good examples of morphogenetic slow waves are ones through fertilizing maize eggs, through developing barnacle eggs and through axolotl embryos during neural induction. Good examples of ultraslow morphogenetic waves are ones during inversion in developing Volvox embryos and across developing Drosophila eye discs. Morphogenetic waves may be best pursued by imaging their calcium with aequorins.

Absorbability of calcium from calcium-bound phosphoryl oligosaccharides in comparison with that from various calcium compounds in the rat ligated jejunum loop.

Science.gov (United States)

To-o, Kenji; Kamasaka, Hiroshi; Nishimura, Takahisa; Kuriki, Takashi; Saeki, Shigeru; Nakabou, Yukihiro

2003-08-01

Calcium-bound phosphoryl oligosaccharides (POs-Ca) were prepared from potato starch. Their solubility and in situ absorbability as a calcium source were investigated by comparing with the soluble calcium compounds, calcium chloride and calcium lactate, or insoluble calcium compounds, calcium carbonate and dibasic calcium phosphate. The solubility of POs-Ca was as high as that of calcium chloride and about 3-fold higher than that of calcium lactate. An in situ experiment showed that the intestinal calcium absorption rate of POs-Ca was almost comparable with that of the soluble calcium compounds, and was significantly higher (pcalcium groups. Moreover, the total absorption rate of a 1:1 mixture of the calcium from POs-Ca and a whey mineral complex (WMC) was significantly higher (psoluble calcium source with relatively high absorption in the intestinal tract.

The role of humic acid on the formation of HAS (hydroxy-aluminosilicate) colloid-borne actinides

Energy Technology Data Exchange (ETDEWEB)

Priemyshev, A.; Kim, M.A. [Inst. fuer Radiochemie, Technische Universitaet Muenchen, D-85748 Garching (Germany); Breban, D.; Panak, P.J.; Yun, J.I.; Kim, J.I.; Fanghanel, Th. [Inst. fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, D-76021 Karlsruhe (Germany); Mansel, A. [Inst. fuer Interdisziplinaere Isotopenforschung, Georadiochemie, Leipzig, D-04318 Leipzig (Germany)

2005-07-01

Full text of publication follows: One of the major unknowns in the process of actinide migration is the formation of their colloid-borne species. Previous studies have been directed to the incorporation of actinides into HAS (hydroxy-aluminosilicate) colloids generated by the nucleation of Si and Al. The present work further pursues the behaviour of actinides at HAS colloid formation but in the presence of humic acid that is known to be an ubiquitous groundwater constituent. The formation and degree of stability of the aluminosilicate binding for the generation of HAS colloids are investigated at first in the absence of actinides. Free and complexed Al resulting from ligand competitions reactions for the complexation of Al with mono-silicic acid, poly-silicic acid and EDTA are monitored spectroscopically by colour reaction. The second part of the study concentrates on the formation and stability of humic colloids using {sup 14}C-labeled humic acid. The activity distribution is ascertained in the ionic, colloidal and precipitated fractions under different conditions of colloid formation, e.g. as a function of pH, time, humic acid and Al concentration. The third part follows the appraisal of appropriate conditions under which stable HAS and humic colloids are formed, and their interaction with actinides, either separately or in competition. Trace actinides of different oxidation states {sup 241}Am(III), {sup 234}Th(IV) and {sup 233}U(VI) are taken for the purpose. HAS colloids generated from poly-silicic acid at neutral pH show EDTA-resistance, whereas HAS colloids formed from mono-silicic acid become EDTA-resistant only by aging (> one month). Humic acid appears to stabilize HAS colloids, unless the loading capacity of humic acid for the Al ion is exceeded. The incorporation of actinides into the colloidal phase is generally enhanced in the presence of humic acid. Synergic effects produce chimeric HAS-humic colloids into which tri-, tetra- and hexavalent actinides

Characterisation of the sarcolemmal calcium pump in guinea pig hearts and its influence through g-strophanthin. Charakterisierung der sarkolemmalen Calciumpumpe des Meerschweinchenherzens und ihre Beeinflussung durch g-Strophanthin

Energy Technology Data Exchange (ETDEWEB)

Lell, R.

1982-11-25

In this work the sarcolemmal calcium transport of the guinea pig heart is studied with the help of the micropore filtration method on the sarcolemmal vesicles. The calcium ATPase could be better characterised by its ability to accumulate calcium in the sarcolemmal vesicles. The calcium pump is magnesium-dependent and positively activated by sodium and potassium. The pH-optimum of the activity lies around 6.8-7.0 depending on intracellular conditions. Up until a concentration of 30 micrograms protein per ml of reaction mixture the calcium accumulation increased proportionally. With higher concentrations it came to a relative decrease. The addition of digitoxin and g-strophanthin to the reaction mixture did not change the activity of the calcium pump. With a perfusion of the heart with a toxic concentration of 10/sup 06/ M g-strophanthin a glycoside intoxication on the beating heart was caused and a time-dependent inhibition of the calcium pump of sarcolemmal vesicles was detectable.

Delayed tooth replantation after root surface treatment with sodium hypochlorite and sodium fluoride: histomorphometric analysis in rats.

Science.gov (United States)

Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

2006-04-01

In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin- embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other.

Sodium

Science.gov (United States)

Table salt is a combination of two minerals - sodium and chloride Your body needs some sodium to work properly. It helps with the function ... in your body. Your kidneys control how much sodium is in your body. If you have too ...

Li+ alumino-silicate ion source development for the Neutralized Drift Compression Experiment (NDCX-II)

International Nuclear Information System (INIS)

Roy, P.K.; Greenway, W.; Kwan, J.W.; Seidl, P.A.; Waldron, W.

2011-01-01

To heat targets to electron-volt temperatures for the study of warm dense matter with intense ion beams, low mass ions, such as lithium, have an energy loss peak (dE/dx) at a suitable kinetic energy. The Heavy Ion Fusion Sciences (HIFS) program at Lawrence Berkeley National Laboratory will carry out warm dense matter experiments using Li + ion beam with energy 1.2-4 MeV in order to achieve uniform heating up to 0.1-1 eV. The accelerator physics design of Neutralized Drift Compression Experiment (NDCX-II) has a pulse length at the ion source of about 0.5 (micro)s. Thus for producing 50 nC of beam charge, the required beam current is about 100 mA. Focusability requires a normalized (edge) emittance ∼2 π-mm-mrad. Here, lithium aluminosilicate ion sources, of β-eucryptite, are being studied within the scope of NDCX-II construction. Several small (0.64 cm diameter) lithium aluminosilicate ion sources, on 70%-80% porous tungsten substrate, were operated in a pulsed mode. The distance between the source surface and the mid-plane of the extraction electrode (1 cm diameter aperture) was 1.48 cm. The source surface temperature was at 1220 C to 1300 C. A 5-6 (micro)s long beam pulsed was recorded by a Faraday cup (+300 V on the collector plate and -300 V on the suppressor ring). Figure 1 shows measured beam current density (J) vs. V 3/2 . A space-charge limited beam density of ∼1 mA/cm 2 was measured at 1275 C temperature, after allowing a conditioning time of about ∼ 12 hours. Maximum emission limited beam current density of (ge) 1.8mA/cm 2 was recorded at 1300 C with 10-kV extractions. Figure 2 shows the lifetime of two typical sources with space-charge limited beam current emission at a lower extraction voltage (1.75 kV) and at temperature of 1265 ± 7 C. These data demonstrate a constant, space-charge limited beam current for 20-50 hours. The lifetime of a source is determined by the loss of lithium from the alumino-silicate material either as ions or as neutral

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

Science.gov (United States)

Jacobs, Brandiese E.; Liu, Yong; Pulina, Maria V.; Golovina, Vera A.

2012-01-01

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 vs. nonpregnant (0.6 ± 0.08 nM; P endogenous and exogenous ouabain is mediated by suppressed NCX1.3 and reduced sensitivity of events downstream of Ca2+ 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

Get Enough Calcium

Science.gov (United States)

... Calcium Print This Topic En español Get Enough Calcium Browse Sections The Basics Overview Foods and Vitamins ... women, don't get enough calcium. How much calcium do I need every day? Women: If you ...

Baroreflex deficiency induces additional impairment of vagal tone, diastolic function and calcium handling proteins after myocardial infarction

Science.gov (United States)

Mostarda, Cristiano; Rodrigues, Bruno; Medeiros, Alessandra; Moreira, Edson D; Moraes-Silva, Ivana C; Brum, Patricia C; Angelis, Katia De; Irigoyen, Maria-Cláudia

2014-01-01

Baroreflex dysfunction has been considered an important mortality predictor after myocardial infarction (MI). However, the impact of baroreflex deficiency prior to MI on tonic autonomic control and cardiac function, and on the profile of proteins associated with intracellular calcium handling has not yet been studied. The aim of the present study was to analyze how the impairment of baroreflex induced by sinoaortic denervation (SAD) prior to MI in rats affects the tonic autonomic control, ventricular function and cardiomyocyte calcium handling proteins. After 15 days of following or SAD surgery, rats underwent MI. Echocardiographic, hemodynamic, autonomic and molecular evaluations were performed 90 days after MI. Baroreflex impairment led to additional damage on: left ventricular remodeling, diastolic function, vagal tonus and intrinsic heart rate after MI. The loss of vagal component of the arterial baroreflex and vagal tonus were correlated with changes in the cardiac proteins involved in intracellular calcium homeostasis. Furthermore, additional increase in sodium calcium exchanger expression levels was associated with impaired diastolic function in experimental animals. Our findings strongly suggest that previous arterial baroreflex deficiency may induce additional impairment of vagal tonus, which was associated with calcium handling proteins abnormalities, probably triggering ventricular diastolic dysfunction after MI in rats. PMID:24936224

The Effects of Dietary Calcium and/or Iron Deficiency upon Murine Intestinal Calcium Binding Protein Activity and Calcium Absorption

OpenAIRE

McDonald, Catherine M.

1980-01-01

Iron deficiency has been shown to impair calcium absorption, leading to decreased bone mass. Vitamin D3-dependent calcium binding protein (CaBP) has been demonstrated to be necessary for the active transport of calcium in the intestine of numerous species. Iron deficiency might affect the activity of the calcium binding protein. Four experimental diets were formulated as follows: Diet 1, iron adequate, calcium adequate; Diet 2, iron deficient, calcium adequate; Diet 3, iron adequate, calci...

Inactivation of Foot-and-Mouth Disease Virus by Citric Acid and Sodium Carbonate with Deicers

Science.gov (United States)

Hong, Jang-Kwan; You, Su-Hwa; Kim, Su-Mi; Tark, Dongseob; Lee, Hyang-Sim; Ko, Young-Joon; Seo, Min-Goo; Park, Jong-Hyeon; Kim, Byounghan

2015-01-01

Three out of five outbreaks of foot-and-mouth disease (FMD) since 2010 in the Republic of Korea have occurred in the winter. At the freezing temperatures, it was impossible to spray disinfectant on the surfaces of vehicles, roads, and farm premises because the disinfectant would be frozen shortly after discharge and the surfaces of the roads or machines would become slippery in cold weather. In this study, we added chemical deicers (ethylene glycol, propylene glycol, sodium chloride, calcium chloride, ethyl alcohol, and commercial windshield washer fluid) to keep disinfectants (0.2% citric acid and 4% sodium carbonate) from freezing, and we tested their virucidal efficacies under simulated cold temperatures in a tube. The 0.2% citric acid could reduce the virus titer 4 logs at −20°C with all the deicers. On the other hand, 4% sodium carbonate showed little virucidal activity at −20°C within 30 min, although it resisted being frozen with the function of the deicers. In conclusion, for the winter season, we may recommend the use of citric acid (>0.2%) diluted in 30% ethyl alcohol or 25% sodium chloride solvent, depending on its purpose. PMID:26319879

Methodology for Extraction of Remaining Sodium of Used Sodium Containers

International Nuclear Information System (INIS)

Jung, Minhwan; Kim, Jongman; Cho, Youngil; Jeong, Jiyoung

2014-01-01

Sodium used as a coolant in the SFR (Sodium-cooled Fast Reactor) reacts easily with most elements due to its high reactivity. If sodium at high temperature leaks outside of a system boundary and makes contact with oxygen, it starts to burn and toxic aerosols are produced. In addition, it generates flammable hydrogen gas through a reaction with water. Hydrogen gas can be explosive within the range of 4.75 vol%. Therefore, the sodium should be handled carefully in accordance with standard procedures even though there is a small amount of target sodium remainings inside the containers and drums used for experiment. After the experiment, all sodium experimental apparatuses should be dismantled carefully through a series of draining, residual sodium extraction, and cleaning if they are no longer reused. In this work, a system for the extraction of the remaining sodium of used sodium drums has been developed and an operation procedure for the system has been established. In this work, a methodology for the extraction of remaining sodium out of the used sodium container has been developed as one of the sodium facility maintenance works. The sodium extraction system for remaining sodium of the used drums was designed and tested successfully. This work will contribute to an establishment of sodium handling technology for PGSFR. (Prototype Gen-IV Sodium-cooled Fast Reactor)

Effects of diphosphonate on kidney calcium content and duodenal absorption of 45calcium

International Nuclear Information System (INIS)

Goulding, A.; Cameron, V.

1978-01-01

In rats the relationships between EHDP-induced changes in serum calcium concentration, kidney calcium content and duodenal transport of 45 calcium were studied. Body weights and kidney weights were similar in all groups. EHDP administration was associated with an increase in serum calcium concentration and kidney calcium content, and a decrease in duodenal 45 calcium transport. In the EHDP-treated rats, there was a significant negative correlation between kidney calcium concentration and duodenal 45 calcium transport but no correlation between either kidney calcium content and serum calcium concentration (r = 0.116) or between serum calcium concentration and duodenal 45 calcium transport (r = 0.02). Further experiments will be needed to determine whether the demonstrated increase in kidney calcium content induced by EHDP administration was the cause of, or was secondary to, inhibition of 1, 25(OH) 2 D 3 synthesis. (orig./AJ) [de

Effect of lowering dietary calcium intake on fractional whole body calcium retention

International Nuclear Information System (INIS)

Dawson-Hughes, B.; Stern, D.T.; Shipp, C.C.; Rasmussen, H.M.

1988-01-01

Although fractional calcium absorption is known to vary inversely with calcium intake, the extent and timing of individual hormonal and calcium absorption responses to altered calcium intake have not been defined. We measured fractional whole body retention of orally ingested 47 Ca, an index of calcium absorption, in nine normal women after they had eaten a 2000-mg calcium diet for 8 weeks and a 300-mg calcium diet for 1, 2, 4, and 8 weeks. After the diet change, serum intact PTH (32.2% increase; P = 0.005), serum 1,25-dihydroxyvitamin D [1,25-(OH)2D; 43.8% increase; P = 0.003], and fractional whole body calcium retention (42.8% increase; P = 0.004) increased within 1 week. Although the PTH and calcium retention responses remained fairly constant throughout the low calcium intake period, serum 1,25-(OH)2D concentrations declined toward baseline after week 1. Thus, the late increase in calcium retention may have resulted from calcium absorption that was independent of 1,25-(OH)2D stimulation

Thermal properties of alkali-activated aluminosilicates with CNT admixture

Science.gov (United States)

Zmeskal, Oldrich; Trhlikova, Lucie; Fiala, Lukas; Florian, Pavel; Cerny, Robert

2017-07-01

Material properties of electrically conductive cement-based materials with increased attention paid on electric and thermal properties were often studied in the last years. Both electric and thermal properties play an important role thanks to their possible utilization in various practical applications (e.g. snow-melting systems or building structures monitoring systems without the need of an external monitoring system). The DC/AC characteristics depend significantly on the electrical resistivity and the electrical capacity of bulk materials. With respect to the DC/AC characteristics of cement-based materials, such materials can be basically classified as electric insulators. In order to enhance them, various conductive admixtures such as those based on different forms of carbon, can be used. Typical representatives of carbon-based admixtures are carbon nanotubes (CNT), carbon fibers (CF), graphite powder (GP) and carbon black (CB). With an adequate amount of such admixtures, electric properties significantly change and new materials with higher added value can be prepared. However, other types of materials can be enhanced in the same way. Alkali-activated aluminosilicates (AAA) based on blast furnace slag are materials with high compressive strength comparable with cement-based materials. Moreover, the price of slag is lower than of Portland cement. Therefore, this paper deals with the study of thermal properties of this promising material with different concentrations of CNT. Within the paper a simple method of basic thermal parameters determination based on the thermal transient response to a heat power step is presented.

Protective Effect of Tetrandrine on Sodium Taurocholate-Induced Severe Acute Pancreatitis

Directory of Open Access Journals (Sweden)

Xian-lin Wu

2015-01-01

Full Text Available Tet is a type of alkaloid extracted from Stephania tetrandra, and it has recently been demonstrated that Tet can protect against inflammation and free radical injury and inhibit the release of inflammatory mediators. The present study was designed to observe the protective effect of Tet on sodium taurocholate-induced severe acute pancreatitis (SAP. The rat model of SAP was induced by retrograde bile duct injection of sodium taurocholate and then treated with Verapamil and Tet. The results showed that Tet can reduce NF-κB activation in pancreas issue, inhibit the SAP cascade, and improve SAP through inducing pancreas acinar cell apoptosis and stabilizing intracellular calcium in the pancreas, thus mitigating the damage to the pancreas. Our study revealed that Tet may reduce systemic inflammatory response syndrome (SIRS and multiple organ dysfunction syndromes (MODS to protect against damage, and these roles may be mediated through the NF-κB pathway to improve the proinflammatory/anti-inflammatory imbalance.

Retention of 60Co, 85Sr and 137Cs on inorganic ion exchangers

International Nuclear Information System (INIS)

Dozol, J.F.; Eymard, S.

1983-11-01

The aim of the study is the treatment of radioactive wastes produced in plutonium fuel fabrication or in spent fuel reprocessing by inorganic ion exchangers for ultimate storage. This rapport, gives the distribution coefficients of 60 Co, 85 Sr, 137 Cs (in sodium nitrate medium at different concentration of sodium: .23g/l, 1 g/l, 10 g/l) obtained with different inorganic exchangers: titanium oxyde, sodium titanate, sodium zirconate, sodium niobate, sodium tantalate, titanium phosphate, zirconium phosphate, ammonium phosphotungstate in zirconium phosphate, polyantimonic acid amorphous aluminosilicate and several zeolites (ZBS 15 from OXYMIN, ZEOLON 400, ZEOLON 500, ZEOLON 900 from Norton, IE 96, A 51, 13 X from Union Carbide) [fr

Calcium signals can freely cross the nuclear envelope in hippocampal neurons: somatic calcium increases generate nuclear calcium transients

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Bading Hilmar

2007-07-01

Full Text Available Abstract Background In hippocampal neurons, nuclear calcium signaling is important for learning- and neuronal survival-associated gene expression. However, it is unknown whether calcium signals generated by neuronal activity at the cell membrane and propagated to the soma can unrestrictedly cross the nuclear envelope to invade the nucleus. The nuclear envelope, which allows ion transit via the nuclear pore complex, may represent a barrier for calcium and has been suggested to insulate the nucleus from activity-induced cytoplasmic calcium transients in some cell types. Results Using laser-assisted uncaging of caged calcium compounds in defined sub-cellular domains, we show here that the nuclear compartment border does not represent a barrier for calcium signals in hippocampal neurons. Although passive diffusion of molecules between the cytosol and the nucleoplasm may be modulated through changes in conformational state of the nuclear pore complex, we found no evidence for a gating mechanism for calcium movement across the nuclear border. Conclusion Thus, the nuclear envelope does not spatially restrict calcium transients to the somatic cytosol but allows calcium signals to freely enter the cell nucleus to trigger genomic events.

Calcium hydroxide isotope effect in calcium isotope enrichment by ion exchange

International Nuclear Information System (INIS)

Jepson, B.E.; Shockey, G.C.

1984-01-01

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( 44 Ca/ 40 Ca) = 11 x 10 -4 and epsilon( 48 Ca/ 40 Ca) = 18 x 10 -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 -4 . 20 references, 2 figures

A study of sodium alginate and calcium chloride interaction through films for intervertebral disc regeneration uses

International Nuclear Information System (INIS)

Laia, Andreia Grossi Santos de; Costa Junior, Ezequiel de Souza; Costa, Hermes de Souza

2014-01-01

The injured intervertebral disc (IVD) requires some measures in order to promote its regeneration. The sodium alginate in conjunction with CaCl_2 forms a net, potentiating its mechanical properties so it may be an alternative for IVD treatment. In this work, the viability of films of sodium alginate crosslinked with CaCl_2 and submitted to variations in their solutions' preparations is verified, comparing the effects of the addition of CaCl_2 through their immersions, before and after drying the films. The films had their physicochemical properties analyzed by FTIR, DSC and XRD. The results indicated that films with a greater proportion of CaCl_2 were more stable in the DSC analysis when compared to films with smaller proportions of CaCl_2. These results indicate alginate's modulation capacity which may be useful for IVD regeneration. (author)

Opposing Roles of Calcium and Intracellular ATP on Gating of the Purinergic P2X2 Receptor Channel

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Milos B. Rokic

2018-04-01

Full Text Available P2X2 receptors (P2X2R exhibit a slow desensitization during the initial ATP application and a progressive, calcium-dependent increase in rates of desensitization during repetitive stimulation. This pattern is observed in whole-cell recordings from cells expressing recombinant and native P2X2R. However, desensitization is not observed in perforated-patched cells and in two-electrode voltage clamped oocytes. Addition of ATP, but not ATPγS or GTP, in the pipette solution also abolishes progressive desensitization, whereas intracellular injection of apyrase facilitates receptor desensitization. Experiments with injection of alkaline phosphatase or addition of staurosporine and ATP in the intracellular solution suggest a role for a phosphorylation-dephosphorylation in receptor desensitization. Mutation of residues that are potential phosphorylation sites identified a critical role of the S363 residue in the intracellular ATP action. These findings indicate that intracellular calcium and ATP have opposing effects on P2X2R gating: calcium allosterically facilitates receptor desensitization and ATP covalently prevents the action of calcium. Single cell measurements further revealed that intracellular calcium stays elevated after washout in P2X2R-expressing cells and the blockade of mitochondrial sodium/calcium exchanger lowers calcium concentrations during washout periods to basal levels, suggesting a role of mitochondria in this process. Therefore, the metabolic state of the cell can influence P2X2R gating.

Calcium-phosphate and parathyroid intradialytic profiles: A potential aid for tailoring the dialysate calcium content of patients on different hemodialysis schedules.

Science.gov (United States)

Ferraresi, Martina; Pia, Anna; Guzzo, Gabriella; Vigotti, Federica Neve; Mongilardi, Elena; Nazha, Marta; Aroasio, Emiliano; Gonella, Cinzia; Avagnina, Paolo; Piccoli, Giorgina Barbara

2015-10-01

Severe hyperparathyroidism is a challenge on hemodialysis. The definition of dialysate calcium (Ca) is a pending issue with renewed importance in cases of individualized dialysis schedules and of portable home dialysis machines with low-flow dialysate. Direct measurement of calcium mass transfer is complex and is imprecisely reflected by differences in start-to-end of dialysis Ca levels. The study was performed in a dialysis unit dedicated to home hemodialysis and to critical patients with wide use of daily and tailored schedules. The Ca-phosphate (P)-parathyroid hormone (PTH) profile includes creatinine, urea, total and ionized Ca, albumin, sodium, potassium, P, PTH levels at start, mid, and end of dialysis. "Severe" secondary hyperparathyroidism was defined as PTH > 300 pg/mL for ≥3 months. Four schedules were tested: conventional dialysis (polysulfone dialyzer 1.8-2.1 m(2) ), with dialysate Ca 1.5 or 1.75 mmol/L, NxStage (Ca 1.5 mmol/L), and NxStage plus intradialytic Ca infusion. Dosages of vitamin D, calcium, phosphate binders, and Ca mimetic agents were adjusted monthly. Eighty Ca-P-PTH profiles were collected in 12 patients. Serum phosphate was efficiently reduced by all techniques. No differences in start-to-end PTH and Ca levels on dialysis were observed in patients with PTH levels dialysis on all schedules except on Nxstage (P dialysis, in "severe" secondary hyperparathyroid patients in order to increase the therapeutic potentials of the new dialysis techniques. © 2015 International Society for Hemodialysis.

Sodium fire tests for investigating the sodium leak in Monju

International Nuclear Information System (INIS)

Seino, Hiroshi; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi

1996-01-01

As a part of the work for investigating the sodium leak accident which occurred in Monju on December 8, 1995, three tests, (1) sodium leak test, (2) sodium fire test-I, and (3) sodium fire test-II, were carried out at OEC/PNC. Main objectives of these tests are to confirm leak and burning behavior of sodium from the damaged thermometer, and effects of the sodium fire on integrity of the surrounding structure, etc. The main conclusions obtained from the tests are shown as below. 1) Average sodium leak rate obtained from the sodium leak test was about 50 g/sec. This was equivalent to the value estimated from level change in the sodium overflow tank in the Monju accident. 2) Observation from video cameras in the sodium fire tests revealed that in early stages of sodium leak, sodium dropped down out of the flexible tube of thermometer in drips. This dripping and burning were expanded in range as sodium splashed on the duct. 3) Though, in the sodium fire test-I, there was a decrease of about 1 mm at a thickness of the burning pan in the vicinity in just under in the leak point, there were completely no crack and failure. In the meantime, in the sodium fire test-II the six open holes were found in the floor liner. By this liner failure, the reaction between sodium and concrete might take place. At present, while the detailed evaluation on the sodium fire test-II has been mainly carried out, the investigation for clarifying the cause of the liner failure has been also carried out. (author)

Calcium

Science.gov (United States)

... You can get decent amounts of calcium from baked beans, navy beans, white beans, and others. Canned fish. You're in luck if you like sardines and canned salmon with bones. Almond milk. Working Calcium Into Your ...