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Sample records for calcium sodium silicate

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

    Science.gov (United States)

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers Cosmetic Ingredient Review (CIR. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the extensive pulmonary damage in humans was the result of direct occupational inhalation of the dusts and noted that lesions seen in animals were affected by particle size, fiber length, and concentration. The Panel considers that most of the formulations are not respirable and of the preparations that are respirable, the concentration of the ingredient is very low. Even so, the Panel considered that any spray containing these solids should be formulated to minimize their inhalation. With this admonition to the cosmetics industry, the CIR Expert Panel concluded that these ingredients are safe as currently used in cosmetic formulations. The Panel did note that the cosmetic ingredient, Talc, is a hydrated magnesium silicate. Because it has a unique crystalline structure that differs from ingredients addressed in this safety assessment, Talc is not included in this report.

  2. 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)

  3. PENGARUH PENAMBAHAN SURFAKTAN SODIUM LIGNOSULFONAT (SLS) DALAM PROSES PENGENDAPAN NANO CALCIUM SILICATE (NCS) DARI GEOTHERMAL BRINE

    OpenAIRE

    Ulya, M Ridho; Perdana, Indra; Mulyono, Panut

    2018-01-01

    Konsentrasi yang tinggi dari kelarutan silika dalam larutan geothermal menyebabkan masalah dalam pengoperasian produksi uap di PLTP Dieng. Mitigasi silika scaling diperlukan untuk mengurangi resiko kegagalan produksi uap. Dalam penelitian ini, asam silika dalam larutan geothermal direaksikan dengan kalsium hidroksida (Ca(OH)2) membentuk n ano calcium silicate (NCS). Tujuan penelitian ini adalah membentuk endapan NCS dari surfaktan SLS dan Ca(OH)2 ke dalam larutan geothermal. Mempelajari perub...

  4. 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.

  5. 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.

  6. Calcium silicate hydrates: Solid and liquid phase composition

    OpenAIRE

    Lothenbach Barbara; Nonat André

    2015-01-01

    © 2015 Elsevier Ltd. This paper presents a review on the relationship between the composition the structure and the solution in which calcium silicate hydrate (C S H) is equilibrated. The silica chain length in C S H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space preferentially at low calcium concentrations and thus by low Ca/Si C S H. Aluminium uptake in C S H ...

  7. LABORATORY INVESTIGATIONS OF SILICATE MUD CONTAMINATION WITH CALCIUM

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2004-12-01

    Full Text Available The silicate-based drilling fluid is a low solids KCl/polymer system with the addition of soluble sodium or potassium silicate to enhance inhibition and wellbore stability. Silicate-based drilling fluids exhibit remarkable shale and chalk stabilizing properties, resulting in gauge hole and the formation of firm cuttings when drilling reactive shales and soft chalks. Silicates protect shales by in-situ gellation when exposed to the neutral pore fluid and precipitation, which occurs on contact with divalent ions present at the surface of the shale. Also, silicates prevent the dispersion and washouts when drilling soft chalk by reacting with the Ca2+ ions present on chalk surfaces of cutting and wellbore to form a protective film. The silicate-based drilling fluid can be used during drilling hole section through shale interbeded anhydrite formations because of its superior shale stabilizing characteristics. However, drilling through the anhydrite can decrease the silicate concentration and change rheological and filtration fluid properties. So, the critical concentration of calcium ions should be investigated by lab tests. This paper details the mechanism of shale inhibition using silicate-based drilling fluid, and presents results of lab tests conducted to ascertain the effect of Ca2+ ions on silicate level in the fluid and the fluid properties.

  8. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    The silicon contents in the roots of the miniature rose treated with polymer sodium silicate were significantly greater than that in plants treated with monomer sodium silicate. In conclusion, the suppressive effects of sodium silicate in the polymer form were confirmed against powdery mildew and root rot diseases of the ...

  9. Suppressive effects of a polymer sodium silicate solution on ...

    African Journals Online (AJOL)

    Mohsen

    2015-10-21

    Oct 21, 2015 ... Sodium silicate was dissolved in water in either a monomer form or polymer form; the effects of both forms of sodium silicate aqueous solution on rose powdery mildew and root rot diseases of miniature rose were examined. Both forms of sodium silicate aqueous solution were applied to the roots of the.

  10. Nanostructure of Calcium Silicate Hydrates in Cements

    KAUST Repository

    Skinner, L. B.

    2010-05-11

    Calcium silicate hydrate (CSH) is the major volume phase in the matrix of Portland cement concrete. Total x-ray scattering measurements with synchrotron x rays on synthetic CSH(I) shows nanocrystalline ordering with a particle diameter of 3.5(5) nm, similar to a size-broadened 1.1 nm tobermorite crystal structure. The CSH component in hydrated tricalcium silicate is found to be similar to CSH(I). Only a slight bend and additional disorder within the CaO sheets is required to explain its nanocrystalline structure. © 2010 The American Physical Society.

  11. Conversion of rice hull ash into soluble sodium silicate

    OpenAIRE

    Edson Luiz Foletto; Ederson Gratieri; Leonardo Hadlich de Oliveira; Sérgio Luiz Jahn

    2006-01-01

    Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA) and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reacti...

  12. Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses

    Science.gov (United States)

    Nitta, Sakiko; Furukawa, Yoshihiro; Kakegawa, Takeshi

    2016-06-01

    Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction has been proposed. The effects of borates have been further analyzed and confirmed in subsequent studies. Nonetheless, the effects of silicates and phosphates remain unclear. In the present study, we incubated aldopentoses in a highly alkaline aqueous solution at a moderate temperature to determine the effects of silicate or phosphate on the degradation rates of ribose and its isomeric aldopentoses. The formation of a complex of silicate (or phosphate) with ribose was also analyzed in experiments with 29Si and 31P nuclear magnetic resonance (NMR). We found that silicate or phosphate complexes of ribose were not detectable under our experimental conditions. The stability of ribose and lyxose improved after addition of 40-fold molar excess (relative to a pentose) of sodium silicate or sodium phosphate to the alkaline solution. The stability was not improved further when an 80-fold molar excess of sodium silicate or sodium phosphate was added. Calcium was removed from these solutions by precipitation of calcium salts. The drop in Ca2+ concentration might have improved the stability of ribose and lyxose, which are susceptible to aldol addition. The improvement of ribose stability by the removal of Ca2+ and by addition of silicate or phosphate was far smaller than the improvement by borate. Furthermore, all aldopentoses showed similar stability in silicate- and phosphate-containing solutions. These results clearly show that selective stabilization of ribose by borate cannot be replaced by the effects of silicate or phosphate; this finding points to the importance of borate in prebiotic RNA formation.

  13. Conversion of rice hull ash into soluble sodium silicate

    Directory of Open Access Journals (Sweden)

    Edson Luiz Foletto

    2006-09-01

    Full Text Available Sodium silicate is used as raw material for several purposes: silica gel production, preparation of catalysts, inks, load for medicines, concrete hardening accelerator, component of detergents and soaps, refractory constituent and deflocculant in clay slurries. In this work sodium silicate was produced by reacting rice hull ash (RHA and aqueous sodium hydroxide, in open and closed reaction systems. The studied process variables were time, temperature of reaction and composition of the reaction mixture (expressed in terms of molar ratios NaOH/SiO2 and H2O/SiO2. About 90% silica conversion contained in the RHA into sodium silicate was achieved in closed system at 200 °C. The results showed that sodium silicate production from RHA can generate aggregate value to this residue.

  14. Calcium silicate hydrates: Solid and liquid phase composition

    Energy Technology Data Exchange (ETDEWEB)

    Lothenbach, Barbara, E-mail: Barbara.lothenbach@empa.ch [Laboratory Concrete & Construction Chemistry, Empa (Switzerland); Nonat, André [ICB, UMR CNRS 6303 CNRS-Université de Bourgogne, Faculté des Sciences et Techniques, BP47870, 21078 Dijon Cedex (France)

    2015-12-15

    This paper presents a review on the relationship between the composition, the structure and the solution in which calcium silicate hydrate (C–S–H) is equilibrated. The silica chain length in C–S–H increases with the silicon concentration and the calcium content in the interlayer space with the calcium concentrations. Sodium and potassium are taken up in the interlayer space, preferentially at low calcium concentrations and thus by low Ca/Si C–S–H. Aluminium uptake in C–S–H increases strongly at higher aluminium concentrations in the solution. At low Ca/Si, aluminium substitutes silica in the bridging position, at Ca/Si > 1 aluminium is bound in TAH. Recently developed thermodynamic models are closely related to the structure of C–S–H and tobermorite, and able to model not only the solubility and the chemical composition of the C–S–H, but also to predict the mean silica chain length and the uptake of aluminium.

  15. Potential of calcium silicate to mitigate water deficiency in maize

    Directory of Open Access Journals (Sweden)

    Douglas José Marques

    2016-01-01

    Full Text Available ABSTRACT The aim of this study was to evaluate the potential of calcium silicate to mitigate the effects of water deficiency in maize plants yield. A completely randomized factorial design, consisting of five combinations of calcium silicate (0, 25, 50, 75, and 100% and five different soil moisture levels (30, 70, 100, 130, and 160%, was adopted. The following parameters were evaluated: soil matric potential, xylem water potential, silicon concentration, leaf dry weight, and dry mass production. Matric potential monitoring confirmed that the irrigation depths employed resulted in different environments for maize plant development during the experiment. Confirming the hypothesis of the study, at the lower irrigation depths, the maize production has accompanied the increase in calcium silicate used as corrective up to the proportion of 50%. These results indicate that silicon mitigated the impact of water deficiency in maize plants and increased the xylem water potential.

  16. 77 FR 21676 - Silicic Acid, Sodium Salt etc.; Tolerance Exemption

    Science.gov (United States)

    2012-04-11

    ... chlorotrimethylsilane and iso-propyl alcohol, reaction with poly(oxypropylene)-poly(oxyethylene) glycol; when used as an... residues of Silicic acid, sodium salt, reaction products with chlorotrimethylsilane and iso-propyl alcohol...-OPP-2011-0934, by one of the following methods. Federal eRulemaking Portal: http://www.regulations.gov...

  17. Wastewater reuse in liquid sodium silicate manufacturing in alexandria, egypt.

    Science.gov (United States)

    Ismail, Gaber A; Abd El-Salam, Magda M; Arafa, Anwar K

    2009-01-01

    Soluble sodium silicates (waterglass) are liquids containing dissolved glass which have some water like properties. They are widely used in industry as sealants, binders, deflocculants, emulsifiers and buffers. Their most common applications in Egypt are in the pulp and paper industry (where they improve the brightness and efficiency of peroxide bleaching) and the detergent industry, in which they improve the action of the detergent and lower the viscosity of liquid soaps. The survey results showed that the production was carried out batch-wise, in an autoclave (dissolver). Sodium silicate in the state of crushed glass was charged in an autoclave (dissolver) with sodium hydroxide and water. The product is filtered through a press. The left over sludge (mud and silicates impurities) is emptied into the local sewer system. Also, sludge (silica gel) was discharged from the neutralization process of the generated alkaline wastewater and consequently clogging the sewerage system. So this study was carried out to modify the current wastewater management system which eliminates sludge formation, the discharge of higher pH wastewater to the sewer system, and to assess its environmental and economic benefits. To assess the characteristics of wastewater to be reused, physico-chemical parameters of 12 samples were tested using standard methods. The survey results showed that a total capacity of the selected enterprise was 540 tons of liquid sodium silicates monthly. The total amount of wastewater being discharged was 335 m3/month. Reusing of wastewater as feed autoclave water reduced water consumption of 32.1% and reduced wastewater discharge/month that constitutes 89.6% as well as saving in final product of 6 ton/month. It was concluded that reusing of wastewater generated from liquid sodium silicate manufacturing process resulted in cheaper and environmental-friendly product.

  18. Thermogravimetric analysis of phase transitions in cement compositions mixed by sodium silicate solution

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    Fedosov Sergey Viktorovich

    2014-01-01

    Full Text Available This paper presents a study of the capability to modify cement by mechanical activation of sodium silicate water solution. Admixtures or blends of binding agents were employed for modifying concrete properties. The liquid glass is applied to protect from chemically or physically unfavorable environmental impacts, such as acidic medium and high temperature. The sodium silicate is a high-capacity setting accelerator. The increasing of the liquid glass proportion in the mix leads to the degradation of the cement paste plasticity and for this reason it is necessary to reduce the amount of liquid glass in the cement paste. The activation of dilute water solution of sodium silicate into rotary pulsating apparatus directly before tempering of the cement paste is an effective way to decrease mass fraction of liquid glass in the cement paste. The results of the combined influence of liquid glass and mechanical activation on physicochemical processes taking place in cement stone are represented in this research. Thermogravimetric analysis was used in order to study cement blends. Thermogravimetric analysis of modified cement stone assays was performed by thermo analyzer SETARAM TGA 92-24. The results of the analysis of phase transition taking place under high-temperature heating of cement stone modified by the mechanical activation of the water solution of the sodium silicate were introduced. Thermograms of cement stone assays were obtained at different hardening age. The comparison of these thermograms allows us to come to a conclusion on the formation and the retention during long time of a more dense structure of the composite matrix mixed by the mechanical activation of sodium silicate water solution. The relation between the concrete composition and its strength properties was stated. Perhaps, the capability of modified concrete to keep calcium ions in sparingly soluble hydrosilicates leads to the increase in its durability and corrosion resistance.

  19. Effect of silicate module of water glass on rheological parameters of poly(sodium acrylate)/sodium silicate hydrogels

    Science.gov (United States)

    Mastalska-Popiawska, J.; Izak, P.

    2017-01-01

    The poly(sodium acrylate)/sodium silicate hydrogels were synthesized in the presence of sodium thiosulphate and potassium persulphate as the redox initiators and N,N’-methylene-bisacrylamide as the cross-linking monomer. 20 wt% aqueous solution of sodium acrylate was polymerized together with water glass with different silicate modules (M) from 1.74 to 2.29, in three mass ratio of the monomer solution to the water glass 2:1, 1:1 and 1:2. Such obtained hybrid composites were rheologically tested using the oscillation method. It allowed to designate the crossover point during polymerization, as well as to define the viscoelastic properties of the casted hydrogel samples one week after the reaction. The obtained results of the oscillation measurements showed that cross-linking reaction proceeds very quickly and the lower the silicate module is, the process starts faster. After the completion of the reaction the silicate-polymer hydrogels are strongly elastic materials and the highest elasticity characterizes systems with the mass ratio 1:2, i.e. with the highest water glass content.

  20. Evaluation of Calcium Silicate Cement Bond Strength after Using ...

    African Journals Online (AJOL)

    2018-01-24

    Jan 24, 2018 ... Objectives: To determine the effect of different gutta‑percha solvents. (chloroform, Endosolv E, orange oil, and eucalyptol) on the push‑out bond strength of calcium silicate cements (CSCs; white mineral trioxide aggregate. [WMTA]; capsule‑form mineral trioxide aggregate [CMTA], and Biodentine). Materials ...

  1. Production test IP-728 half-plant sodium silicate test. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.

    1966-07-28

    The sodium silicate addition to the coolant reduced the effluent concentrations of certain radionuclides. Nothing was observed during the course of the test to indicate that sodium silicate could not be used at all plants. However, the reductions obtained in effluent activity are not believed commensurate with the cost of silicate usage.

  2. Characterization of modified calcium-silicate cements exposed to acidic environment

    Energy Technology Data Exchange (ETDEWEB)

    Camilleri, Josette, E-mail: josette.camilleri@um.edu.mt

    2011-01-15

    Portland cement which is used as a binder in concrete in the construction industry has been developed into a biomaterial. It is marketed as mineral trioxide aggregate and is used in dentistry. This material has been reported to be very biocompatible and thus its use has diversified. The extended use of this material has led to developments of newer versions with improved physical properties. The aim of this study was to evaluate the effect of acidic environments found in the oral cavity on fast setting calcium silicate cements with improved physical properties using a combination of techniques. Two fast setting calcium silicate cements (CSA and CFA) and two cement composites (CSAG and CFAG) were assessed by subjecting the materials to lactic acid/sodium lactate buffer gel for a period of 28 days. At weekly intervals the materials were viewed under the tandem scanning confocal microscope (TSM), and scanning electron microscope (SEM). The two prototype cements exhibited changes in their internal chemistry with no changes in surface characteristics. Since the changes observed were mostly sub-surface evaluation of surface characteristics of cement may not be sufficient in the determination of chemical changes occurring. - Research Highlights: {yields} An acidic environment affects modified fast setting calcium silicate-based cements. {yields} No surface changes are observed in acidic environment. {yields} An acidic environment causes sub-surface changes in the material chemistry which are only visible in fractured specimens. {yields} A combination of techniques is necessary in order to evaluate the chemical changes occurring.

  3. NMR study of hydrated calcium silicates; Etude par RMN de la structure des silicates de calcium hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Klur, I

    1996-02-26

    Radioactive wastes storage methods are developed by the CEA. As cements are important materials as well for hours living radioisotopes than for years living radioisotopes, a better knowledge of this material will allow to anticipate its behaviour and to obtain safer storage methods. The structure of calcium silicates (C-S-H) (main constituent of cements) have then been determined in this thesis by nuclear magnetic resonance. This method has allow to explain in structural terms, the different calcium rates that can be measured in the C-S-H too. (O.M.) 101 refs.

  4. Durability of metakaolin geopolymers with various sodium silicate/sodium hydroxide ratios against seawater exposure

    Science.gov (United States)

    Jaya, Nur Ain; Abdullah, Mohd Mustafa Al Bakri; Li, Long-Yuan; Sandu, Andrei Victor; Hussin, Kamarudin; Ming, Liew Yun

    2017-09-01

    This work presents an investigation of the performance of metakaolin geopolymers exposed to the continuous immersion of seawater. The geopolymers were prepared from metakaolin by activating with a mixture of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) solutions and cured at 80°C. The ratios of sodium silicate to sodium hydroxide were varied from 0.20 to 0.32. The result showed that metakaolin geopolymers reduce in strength after immersion in seawater for 28 days. The unexposed samples with highest compressive strength attained greatest strength retention. White deposits were formed on the surface of the geopolymers after the exposure to seawater which was believed due to the depolymerisation process of the geopolymer network. Even so, the metakaolin geopolymers did not substantially change in dimension and remain structurally intact.

  5. Novel understanding of calcium silicate hydrate from dilute hydration

    KAUST Repository

    Zhang, Lina

    2017-05-13

    The perspective of calcium silicate hydrate (C-S-H) is still confronting various debates due to its intrinsic complicated structure and properties after decades of studies. In this study, hydration at dilute suspension of w/s equaling to 10 was conducted for tricalcium silicate (C3S) to interpret long-term hydration process and investigate the formation, structure and properties of C-S-H. Based on results from XRD, IR, SEM, NMR and so forth, loose and dense clusters of C-S-H with analogous C/S ratio were obtained along with the corresponding chemical formulae proposed as Ca5Si4O13∙6.2H2O. Crystalline structure inside C-S-H was observed by TEM, which was allocated at the foil-like proportion as well as the edge of wrinkles of the product. The long-term hydration process of C3S in dilute suspension could be sketchily described as migration of calcium hydroxide and in-situ growth of C-S-H with equilibrium silicon in aqueous solution relatively constant and calcium varied.

  6. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates.

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations' setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05).

  7. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Abstract Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations’ setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05). PMID:26787304

  8. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

    Full Text Available The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7 using eggshell biowaste (as calcium source, magnesium nitrate and tetraethyl orthosilicate (TEOS as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy (SEM techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP layer on its surface and predicting its possibilities for applications in hard tissue regeneration.

  9. Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

    Science.gov (United States)

    Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-11-01

    Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively. Moreover, the use of sodium silicate resulted in the formation of distinct microstructure and incorporation of silicate into the oxide film. These oxide films reduced the anodic activity 4 times, while the corrosion protection by silicate containing oxide was the function of its concentration. Further, in acid salt spray and filiform corrosion tests, oxide layer containing silicate exhibited two times higher corrosion resistance.

  10. Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

    Science.gov (United States)

    Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

    2014-06-01

    To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (penamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (penamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

  11. Influence of iron on crystallization behavior and thermal stability of the insulating materials - porous calcium silicates

    DEFF Research Database (Denmark)

    Haastrup, Sonja; Yu, Donghong; Yue, Yuanzheng

    2017-01-01

    The properties of porous calcium silicate for high temperature insulation are strongly influenced by impurities. In this work we determine the influence of Fe3+ on the crystallization behavior and thermal stability of hydrothermally derived calcium silicate. We synthesize porous calcium silicate...... by XRD analysis. The thermal stability and compressive strength of the calcium silicates are seriously influenced by the changes of their crystal structure. Linear shrinkage of the reference sample is 1.3% at 1050°C, whereas the sample with Fe/Si =1.0% does by 30.4%. In conclusion, the presence of Fe3......+ modifies the crystal structure of porous calcium silicates, leading to a significant shrinkage in these materials....

  12. In vitro cytotoxicity of calcium silicate-containing endodontic sealers.

    Science.gov (United States)

    Zhou, Hui-min; Du, Tian-feng; Shen, Ya; Wang, Zhe-jun; Zheng, Yu-feng; Haapasalo, Markus

    2015-01-01

    The cytotoxicity of 2 novel calcium silicate-containing endodontic sealers to human gingival fibroblasts was studied. EndoSequence BC (Brasseler, Savannah, GA), MTA Fillapex (Angelus Indústria de Produtos Odontológicos S/A, Londrina, PR, Brazil) and a control sealer (AH Plus; Dentsply DeTrey GmbH, Konstanz, Germany) were evaluated. Human gingival fibroblasts were incubated for 3 days both with the extracts from fresh and set materials in culture medium and cultured on the surface of the set materials in Dulbecco-modified Eagle medium. Fibroblasts cultured in Dulbecco-modified Eagle medium were used as a control group. Cytotoxicity was evaluated by flow cytometry, and the adhesion of the fibroblasts to the surface of the set materials was assessed using scanning electron microscopy. The data of cell cytotoxicity were analyzed statistically using a 1-way analysis of variance test at a significance level of P extracts from BC Sealer showed higher viabilities at all extract concentrations than cells incubated with extracts from freshly mixed AH Plus and fresh and set MTA Fillapex, esspecially for the high extract concentrations (1:2 and 1:8 dilutions). Extracts from set MTA Fillapex of 2 weeks and older were more cytotoxic than extracts from freshly mixed and 1-week-old cement. With extract concentrations of 1:32 and lower, MTA Fillapex was no longer cytotoxic. After setting, AH Plus was no longer cytotoxic, and the fibroblast cells grew on set AH Plus equally as well as on BC Sealer. BC Sealer and MTA Fillapex, the 2 calcium silicate-containing endodontic sealers, exhibited different cytotoxicity to human gingival fibroblasts. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  13. Potassium silicate and calcium silicate on the resistance of soybean to Phakopsora pachyrhizi infection

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Cruz

    2013-01-01

    Full Text Available The control of Asian Soybean Rust (ASR, caused by Phakopsora pachyrhizi, has been difficult due to the aggressiveness of the pathogen and the lack of resistant cultivars. The objective of this study was to evaluate the effects of spray of potassium silicate (PS and soil amendment with calcium silicate (CS on soybean resistance to ASR. The PS solution was sprayed to leaves 24 hours prior to fungal inoculation while CS was amended to the soil at thirty-five days before sowing. The infection process of P. pachyrhizi was investigated by scanning electron microscopy. The uredia on leaves of plants sprayed with PS were smaller and more compact than those observed on the leaves of plants grown in soil amended with CS or in soil non-amended with CS (control treatment. On leaves of plants from the control treatment, uredia produced many urediniospores at 9 days after inoculation, and the ASR severity was 15, 8 and 9%, respectively, for plants from control, PS and CS treatments. In conclusion, the spray of PS contributed to reduce the number of uredia per cm² of leaf area and both PS spray and CS resulted in lower ASR symptoms.

  14. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill − Part 1

    Directory of Open Access Journals (Sweden)

    M. Kermani

    2015-06-01

    Full Text Available In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investigated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF. The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The mechanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength and physical (water retention properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  15. Molecular Dynamics Modeling of Hydrated Calcium-Silicate-Hydrate (CSH) Cement Molecular Structure

    Science.gov (United States)

    2014-08-30

    paste consisting of starting configuration of dry cement powder and water mixture by itself is a complex, multi-scale material system. Though...high pressure molecular structural behavior of the hydrated CSH. Portland cement in the powder form consists of four different major constituents...Tricalcium silicate (C3S), Di-Calcium silicate (C2S), Tri-Calcium aluminate (C3A), and Tetra calcium aluminoferrite (C4AF) [1]. Different mixture

  16. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, Steven D.; Moeini, Sina; Büyüköztürk, Oral, E-mail: obuyuk@mit.edu [Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yip, Sidney [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-07-21

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  17. Comparison of Ferrous Calcium Silicate Slag and Calcium Ferrite Slag Interactions with Magnesia-Chrome Refractories

    Science.gov (United States)

    Kaur, R. R.; Swinbourne, D. R.; Wadsley, M. W.; Nexhip, C.

    2011-06-01

    The cost of maintaining and eventually replacing refractories as a result of slag attack is a significant cost component in the copper industry. Converting matte to blister copper takes place in reactors lined with direct-bonded magnesia-chrome refractories, and several continuous converting operations use calcium ferrite slag. Unfortunately, the low viscosity of calcium ferrite slag makes it aggressive toward the refractories. Ferrous calcium silicate (FCS) slag has been proposed as a replacement; however, the effect of this slag on magnesia-chrome refractories has not been studied. In this work, the interactions between FCS slag and magnesia-chrome refractory at 1573 K (1300 °C) with an oxygen partial pressure of 10-6 atm were studied and compared with that experienced with calcium ferrite slag under the same conditions. Both slags penetrated the pores in the refractory and caused compositional change in the chromite spinel intergranular bonding phase through cation interdiffusion, which resulted in cracking and debonding of periclase grains. It was observed that the refractory was penetrated much more deeply by calcium ferrite slag than FCS slag because of the higher surface tension and lower viscosity of calcium ferrite slag. As a result, the refractory was attacked less by FCS slag than it was by calcium ferrite slag. It is concluded that the use of FCS slag in continuous copper converting is likely to extend refractory life.

  18. Optical analysis of samarium doped sodium bismuth silicate glass.

    Science.gov (United States)

    Thomas, V; Sofin, R G S; Allen, M; Thomas, H; Biju, P R; Jose, G; Unnikrishnan, N V

    2017-01-15

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3+‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Removal of lead from cathode ray tube funnel glass by generating the sodium silicate.

    Science.gov (United States)

    Hu, Biao; Zhao, Shuangshuang; Zhang, Shuhao

    2015-01-01

    In the disposal of electronic waste, cathode ray tube (CRT) funnel glass is an environmental problem of old television sets. Removal of the lead from CRT funnel glass can prevent its release into the environment and allow its reuse. In this research, we reference the dry progress productive technology of sodium silicate, the waste CRT glass was dealt with sodium silicate frit melted and sodium silicate frit dissolved. Adding a certain amount of Na ₂CO₃to the waste CRT glass bases on the material composition and content of it, then the specific modulus of sodium silicate frit is obtained by melting progress. The silicon, potassium and sodium compounds of the sodium silicate frit are dissolved under the conditions of high temperature and pressure by using water as solvent, which shows the tendency that different temperature, pressure, liquid-solid ratio and dissolving time have effect on the result of dissolving. At 175°C(0.75MPa), liquid-solid ratio is 1.5:1, the dissolving time is 1h, the dissolution rate of sodium silicate frit is 44.725%. By using sodium sulfide to separate hydrolysis solution and to collect lead compounds in the solution, the recovery rate of lead in dissolving reached 100% and we can get clean sodium silicate and high purity of lead compounds. The method presented in this research can recycle not only the lead but also the sodium, potassium and other inorganic minerals in CRT glass and can obtain the comprehensive utilization of leaded glass.

  20. Modulation of L-type calcium channels by sodium ions.

    OpenAIRE

    Balke, C W; Wier, W G

    1992-01-01

    It is universally believed that the removal of external sodium ions is without effect on calcium current. We now report that in enzymatically isolated guinea pig ventricular cells, the replacement of external sodium ions with certain other cations causes a 3- to 6-fold increase in peak L-type calcium current. The increase in current is reversibly blocked by L-type calcium-channel antagonists, not mediated by changes in internal calcium, and is inhibited by intracellular 5'-adenylyl imidodipho...

  1. Mesoporous Calcium Silicate Nanoparticles with Drug Delivery and Odontogenesis Properties.

    Science.gov (United States)

    Huang, Ching-Yuang; Huang, Tsui-Hsien; Kao, Chia-Tze; Wu, Yuan-Haw; Chen, Wan-Chen; Shie, Ming-You

    2017-01-01

    Calcium silicate (CS) -based materials play an important role in the development of endodontic materials that induce bone/cementum tissue regeneration and inhibit bacterial viability. The aim of this study was to prepare novel mesoporous CS (MesoCS) nanoparticles that have osteogenic, drug delivery, and antibacterial characteristics for endodontic materials and also have an excellent ability to develop apatite mineralization. The MesoCS nanoparticles were prepared using sol-gel methods. In addition, the mesoporous structure, specific surface area, pore volume, and morphology of the MesoCS nanoparticles were analyzed. The apatite mineralization ability, in vitro odontogenic differentiation, drug delivery, and antibacterial properties of the MesoCS nanoparticles were further investigated. The results indicate that the 200-nm-sized MesoCS nanoparticles synthesized using a facile template method exhibited a high specific surface area and pore volume with internal mesopores (average pore size = 3.05 nm). Furthermore, the MesoCS nanoparticles can be used as drug carriers to maintain sustained release of gentamicin and fibroblast growth factor-2 (FGF-2). The MesoCS-loaded FGF-2 might stimulate more odontogenic-related protein than CS because of the FGF-2 release. Based on this work, it can be inferred that MesoCS nanoparticles are potentially useful endodontic materials for biocompatible and osteogenic dental pulp tissue regenerative materials. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Nanoporous Calcium Silicate and PLGA Biocomposite for Bone Repair

    Directory of Open Access Journals (Sweden)

    Jiacan Su

    2010-01-01

    Full Text Available Nanoporous calcium silicate (n-CS with high surface area was synthesized using the mixed surfactants of EO20PO70EO20 (polyethylene oxide20(polypropylene oxide70(polyethylene oxide20, P123 and hexadecyltrimethyl ammonium bromide (CTAB as templates, and its composite with poly(lactic acid-co-glycolic acid (PLGA were fabricated. The results showed that the n-CS/PLGA composite (n-CPC with 20 wt% n-CS could induce a dense and continuous layer of apatite on its surface after soaking in simulated body fluid (SBF for 1 week, suggesting the excellent in vitro bioactivity. The n-CPC could promote cell attachment on its surfaces. In addition, the proliferation ratio of MG63 cells on n-CPC was significantly higher than PLGA; the results demonstrated that n-CPC had excellent cytocompatibility. We prepared n-CPC scaffolds that contained open and interconnected macropores ranging in size from 200 to 500 μm. The n-CPC scaffolds were implanted in femur bone defect of rabbits, and the in vivo biocompatibility and osteogenicity of the scaffolds were investigated. The results indicated that n-CPC scaffolds exhibited good biocompatibility, degradability, and osteogenesis in vivo. Collectively, these results suggested that the incorporation of n-CS in PLGA produced biocomposites with improved bioactivity and biocompatibility.

  3. Sodium silicate solutions from dissolution of glasswastes. Statistical analysis

    Directory of Open Access Journals (Sweden)

    Torres-Carrasco, M.

    2014-05-01

    Full Text Available It has studied the solubility process of four different waste glasses (with different particle sizes, 125 µm in alkaline solutions (NaOH and NaOH/Na₂CO₃ and water as a reference and under different conditions of solubility (at room temperature, at 80°C and a mechano-chemical process. Have established the optimal conditions of solubility and generation of sodium silicates solutions, and these were: the smaller particle size (Se ha estudiado el proceso de solubilidad de cuatro diferentes residuos vítreos (con distintas granulometrías, 125 µm en disoluciones alcalinas de NaOH y NaOH/Na₂CO₃ y agua como medio de referencia y bajo distintas condiciones de solubilidad (a temperatura ambiente, a 80°C y con un proceso mecano-químico. Se han establecido las condiciones óptimas de solubilidad y generación de disoluciones de silicato sódico, y estas son: menor tamaño de partícula del residuo vítreo (inferior a 45 µm, con la disolución de NaOH/Na₂CO₃ y tratamiento térmico a 80°C durante 6 horas de agitación. El análisis estadístico realizado a los resultados obtenidos da importancia a las variables estudiadas y a las interacciones de las mismas. A través de ²⁹Si RMN MAS se ha confirmado la formación, tras los procesos de disolución, de un silicato monomérico, apto para su utilización como activador en la preparación de cementos y hormigones alcalinos.

  4. Sol-Gel Synthesis, X-Ray Diffraction Studies, and Electric Conductivity of Sodium Europium Silicate

    Directory of Open Access Journals (Sweden)

    Ekaterina V. Borisova

    2013-01-01

    Full Text Available Sodium europium silicate, NaEu9(SiO46O2, with apatite structure has been obtained and studied using X-ray diffraction and SEM. It has been shown that sodium sublimation does not take place upon synthesis by the sol-gel method. Rietveld refinement has revealed that sodium atoms are ordered and occupy the 4f position. O(4 atoms not related to silicate ions are placed at the centers of Eu(2 triangles. DC and AC electric conductivity and activation energy have been determined for the compound studied.

  5. A Comparative Chemical Study of Calcium Silicate-Containing and Epoxy Resin-Based Root Canal Sealers

    Directory of Open Access Journals (Sweden)

    Przemysław Reszka

    2016-01-01

    Full Text Available Objective. The present study assessed the chemical elements in two novel calcium silicate-containing root canal sealers, BioRoot RCS and Well-Root ST, compared to a calcium silicate-containing root canal sealer that has been on the market for several years, MTA Fillapex, and epoxy resin-based sealer AHPlus. Material and Methods. The sealers were mixed and manipulated according to the manufacturers’ instructions. Twelve cylindrical molds (inner diameter 4 mm; height 3 mm were placed on a glass petri dish and packed with the materials. The dish was transferred to an incubator. After 72 h the molds were examined by scanning electron microscopy and energy dispersive X-ray microanalysis. Results. BioRoot RCS and Well-Root ST had high peaks of calcium, zirconium, oxygen, carbon, silicon, and chlorine. Well-Root ST also had sodium, magnesium, aluminum, and titanium peaks. MTA Fillapex and AHPlus had carbon, oxygen, calcium, titanium, and bismuth peaks. A silicon peak was also observed for MTA Fillapex, and zirconium and tungsten peaks for AHPlus. Conclusion. BioRoot RSC had the highest degree of purity. The clinical implication of metals contained in the other sealers needs to be investigated.

  6. A Comparative Chemical Study of Calcium Silicate-Containing and Epoxy Resin-Based Root Canal Sealers.

    Science.gov (United States)

    Reszka, Przemysław; Nowicka, Alicja; Lipski, Mariusz; Dura, Włodzimierz; Droździk, Agnieszka; Woźniak, Krzysztof

    2016-01-01

    Objective. The present study assessed the chemical elements in two novel calcium silicate-containing root canal sealers, BioRoot RCS and Well-Root ST, compared to a calcium silicate-containing root canal sealer that has been on the market for several years, MTA Fillapex, and epoxy resin-based sealer AHPlus. Material and Methods. The sealers were mixed and manipulated according to the manufacturers' instructions. Twelve cylindrical molds (inner diameter 4 mm; height 3 mm) were placed on a glass petri dish and packed with the materials. The dish was transferred to an incubator. After 72 h the molds were examined by scanning electron microscopy and energy dispersive X-ray microanalysis. Results. BioRoot RCS and Well-Root ST had high peaks of calcium, zirconium, oxygen, carbon, silicon, and chlorine. Well-Root ST also had sodium, magnesium, aluminum, and titanium peaks. MTA Fillapex and AHPlus had carbon, oxygen, calcium, titanium, and bismuth peaks. A silicon peak was also observed for MTA Fillapex, and zirconium and tungsten peaks for AHPlus. Conclusion. BioRoot RSC had the highest degree of purity. The clinical implication of metals contained in the other sealers needs to be investigated.

  7. Hydration characteristics of calcium silicate cements with alternative radiopacifiers used as root-end filling materials.

    Science.gov (United States)

    Camilleri, Josette

    2010-03-01

    Mineral trioxide aggregate (MTA) is composed of calcium silicate cement and bismuth oxide added for radiopacity. The bismuth oxide in MTA has been reported to have a deleterious effect on the physical and chemical properties of the hydrated material. This study aimed to investigate the hydration mechanism of calcium silicate cement loaded with different radiopacifiers for use as a root-end filling material. Calcium silicate cement loaded with barium sulfate, gold, or silver/tin alloy was hydrated, and paste microstructure was assessed after 30 days. In addition, atomic ratio plots of Al/Ca versus Si/Ca and S/Ca and Al/Ca were drawn, and X-ray energy dispersive analysis of the hydration products was performed to assess for inclusion of heavy metals. The leachate produced from the cements after storage of the cements in water for 28 days and the leaching of the radiopacifiers in an alkaline solution was assessed by using inductively coupled plasma. The hydrated calcium silicate cement was composed of calcium silicate hydrate, calcium hydroxide, ettringite, and monosulfate. Unhydrated cement particles were few. No heavy metals were detected in the calcium silicate hydrate except for the bismuth in MTA. Calcium was leached out early in large quantities that reduced with time. The barium and bismuth were leached in increasing amounts. Copper was the most soluble in alkaline solution followed by bismuth and barium in smaller amounts. The bismuth oxide can be replaced by other radiopacifiers that do not affect the hydration mechanism of the resultant material. Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Effect of Different Irrigation Solutions on the Colour Stability of Three Calcium Silicate-Based Materials.

    Science.gov (United States)

    F, Sobhnamayan; A, Adl; S, Ghanbaran

    2017-06-01

    Previous studies have shown discoloration of mineral trioxide aggregate (MTA) in contact with root canal irrigation solutions. However, there are limited data on colour stability of other calcium silicate-based materials (CSMs). This in vitro study aimed to evaluate the colour stability of three CSMs in contact with different irrigation solutions. Three CSMs including White MTA (wMTA) Angelus, calcium enriched mixture (CEM), and Biodentine were assessed in this study. Forty five samples of each material were mixed according to the manufactures' instructions and then placed in silicone tubes. After 24 hours, the materials were removed from the moulds and 9 samples of each material left dry or immersed in normal saline, 5% sodium hypochlorite (NaOCL), 2% chlorhexidinegluconate (CHX), or 17%EDTA for 24 hours. Colour changes were measured with a spectrophotometer. Data were evaluated with 2-way analysis of variance, one way analysis of variance and Tukey post hoc tests. The highest discoloration of all materials was observed after contact with CHX. In the MTA Angelus and CEM cement groups, significant differences were observed between CHX and NaOCl and also between these two irrigants with the other three irrigants ( p < 0.05). In the Biodentine group, CHX created statistically significant discoloration compared to other irrigants ( p < 0.05). Only wMTA Angelus showed a significantly higher discoloration in contact with EDTA compared to normal saline and dry condition ( p < 0.05). wMTA Angelus showed a significantly higher colour change compared with CEM cement and Biodentine after contact with NaOCl, CHX, and EDTA ( p < 0.05). The contact of wMTA, CEM cement, and Biodentine with CHX should be avoided because this leads to severe discoloration. Contact with sodium hypochlorite also leads to discoloration of wMTA and CEM cements. Among of the three tested materials, wMTA showed the highest discoloration after contact with NaOCl, CHX, and EDTA.

  9. Production of biodiesel and lactic acid from rapeseed oil using sodium silicate as catalyst.

    Science.gov (United States)

    Long, Yun-Duo; Guo, Feng; Fang, Zhen; Tian, Xiao-Fei; Jiang, Li-Qun; Zhang, Fan

    2011-07-01

    Biodiesel and lactic acid from rapeseed oil was produced using sodium silicate as catalyst. The transesterification in the presence of the catalyst proceeded with a maximum yield of 99.6% under optimized conditions [3% (w/w) sodium silicate, methanol/oil molar ratio 9/1, reaction time 60 min, reaction temperature 60°C, and stirring rate 250 rpm]. After six consecutive transesterification reactions, the catalyst was collected and used for catalysis of the conversion of glycerol to lactic acid. A maximum yield of 80.5% was achieved when the reaction was carried out at a temperature of 300°C for 90 min. Thus, sodium silicate is an effective catalyst for transesterification and lactic acid production from the biodiesel by-product, glycerol. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Preparation and properties of isotropic Nd-Fe-B bonded magnets with sodium silicate binder

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.Q.; Hu, R.J.; Yue, M., E-mail: yueming@bjut.edu.cn; Yin, Y.X.; Zhang, D.T.

    2017-08-01

    Graphical abstract: To improve the working temperature of bonded Nd-Fe-B magnets, the heat-resistant binder, sodium silicate, was used to prepare new type bonded Nd-Fe-B magnets. The three-dimensional Si-O-Si structure formed in the curing process has excellent strength; it can ensure that the bonded magnets have a certain shape and usable magnetic properties when working at 200 °C. - Highlights: • Sodium silicate enables bonded Nd-Fe-B magnets to be used for higher operation temperatures. • The sodium silicate bonded magnets exhibit usable maximum energy product of 4.057 MGOe at 200 °C. • The compressive strength of sodium silicate bonded magnets is twice bigger than that of epoxy resin bonded magnets. - Abstract: In present study, sodium silicate, a kind of heat-resistant binder, was used to prepare bonded Nd-Fe-B magnets with improved thermal stability and mechanical strength. Effect of curing temperature and curing time of the new binder to the magnetic properties, microstructure, and mechanical strength of the magnets was systematically investigated. Fracture surface morphology observation show that sodium silicate in bonded magnets could completely be cured at 175 °C for 40 min, and the magnets prepared under this condition exhibit optimal properties. They exhibit usable magnetic properties of B{sub r} of 4.66 kGs, H{sub cj} of 4.84 kOe, and (BH){sub max} of 4.06 MGOe at 200 °C. Moreover, the magnets possess high compressive strength of 63 MPa.

  11. Testing Urey's carbonate-silicate cycle using the calcium isotopic composition of sedimentary carbonates

    Science.gov (United States)

    Blättler, Clara L.; Higgins, John A.

    2017-12-01

    Carbonate minerals constitute a major component of the sedimentary geological record and an archive of a fraction of the carbon and calcium cycled through the Earth's surface reservoirs for over three billion years. For calcium, carbonate minerals constitute the ultimate sink for almost all calcium liberated during continental and submarine weathering of silicate minerals. This study presents >500 stable isotope ratios of calcium in Precambrian carbonate sediments, both limestones and dolomites, in an attempt to characterize the isotope mass balance of the sedimentary carbonate reservoir through time. The mean of the dataset is indistinguishable from estimates of the calcium isotope ratio of bulk silicate Earth, consistent with the Urey cycle being the dominant mechanism exchanging calcium among surface reservoirs. The variability in bulk sediment calcium isotope ratios within each geological unit does not reflect changes in the global calcium cycle, but rather highlights the importance of local mineralogical and/or diagenetic effects in the carbonate record. This dataset demonstrates the potential for calcium isotope ratios to help assess these local effects, such as the former presence of aragonite, even in rocks with a history of neomorphism and recrystallization. Additionally, 29 calcium isotope measurements are presented from ODP (Ocean Drilling Program) Site 801 that contribute to the characterization of altered oceanic crust as an additional sink for calcium, and whose distinct isotopic signature places a limit on the importance of this subduction flux over Earth history.

  12. Sodium Silicate Behavior in Porous Media Applied for In-Depth Profile Modifications

    Directory of Open Access Journals (Sweden)

    Hossein A. Akhlaghi Amiri

    2014-03-01

    Full Text Available This paper addresses alkaline sodium silicate (Na-silicate behavior in porous media. One of the advantages of the Na-silicate system is its water-like injectivity during the placement stage. Mixing Na-silicate with saline water results in metal silicate precipitation as well as immediate gelation. This work demonstrated that low salinity water (LSW, sea water diluted 25 times could be used as a pre-flush in flooding operations. A water override phenomenon was observed during gel formation which is caused by gravity segregation. Dynamic adsorption tests in the sand-packed tubes showed inconsiderable adsorbed silicon density (about 8.5 × 10−10 kg/cm3 for a solution with 33 mg/L silicon content, which is less than the estimated mono-layer adsorption density of 1.4 × 10−8 kg/cm3. Na-silicate enhanced water sweep efficiency after application in a dual-permeability sand-pack system, without leak off into the oil-bearing low permeability (LP zone. Field-scale numerical sensitivity studies in a layered reservoir demonstrated that higher permeability and viscosity contrasts and lower vertical/horizontal permeability ratio result in lower Na-silicate leakoff into the matrix. The length of the mixing zone between reservoir water and the injected Na-silicate solution, which is formed by low salinity pre-flush, acts as a buffer zone.

  13. Determine the compressive strength of calcium silicate bricks by combined nondestructive method.

    Science.gov (United States)

    Brozovsky, Jiri

    2014-01-01

    The paper deals with the application of combined nondestructive method for assessment of compressive strength of calcium silicate bricks. In this case, it is a combination of the rebound hammer method and ultrasonic pulse method. Calibration relationships for determining compressive strength of calcium silicate bricks obtained from nondestructive parameter testing for the combined method as well as for the L-type Schmidt rebound hammer and ultrasonic pulse method are quoted here. Calibration relationships are known for their close correlation and are applicable in practice. The highest correlation between parameters from nondestructive measurement and predicted compressive strength is obtained using the SonReb combined nondestructive method. Combined nondestructive SonReb method was proved applicable for determination of compressive strength of calcium silicate bricks at checking tests in a production plant and for evaluation of bricks built in existing masonry structures.

  14. Confined Water in Layered Silicates: The Origin of Anomalous Thermal Expansion Behavior in Calcium-Silicate-Hydrates.

    Science.gov (United States)

    Krishnan, N M Anoop; Wang, Bu; Falzone, Gabriel; Le Pape, Yann; Neithalath, Narayanan; Pilon, Laurent; Bauchy, Mathieu; Sant, Gaurav

    2016-12-28

    Water, under conditions of nanoscale confinement, exhibits anomalous dynamics, and enhanced thermal deformations, which may be further enhanced when such water is in contact with hydrophilic surfaces. Such heightened thermal deformations of water could control the volume stability of hydrated materials containing nanoconfined structural water. Understanding and predicting the thermal deformation coefficient (TDC, often referred to as the CTE, coefficient of thermal expansion), which represents volume changes induced in materials under conditions of changing temperature, is of critical importance for hydrated solids including: hydrogels, biological tissues, and calcium silicate hydrates, as changes in their volume can result in stress development, and cracking. By pioneering atomistic simulations, we examine the physical origin of thermal expansion in calcium-silicate-hydrates (C-S-H), the binding agent in concrete that is formed by the reaction of cement with water. We report that the TDC of C-S-H shows a sudden increase when the CaO/SiO2 (molar ratio; abbreviated as Ca/Si) exceeds 1.5. This anomalous behavior arises from a notable increase in the confinement of water contained in the C-S-H's nanostructure. We identify that confinement is dictated by the topology of the C-S-H's atomic network. Taken together, the results suggest that thermal deformations of hydrated silicates can be altered by inducing compositional changes, which in turn alter the atomic topology and the resultant volume stability of the solids.

  15. Effect of phase composition of calcium silicate phosphate component on properties of brushite based composite cements

    Energy Technology Data Exchange (ETDEWEB)

    Sopcak, T., E-mail: tsopcak@imr.saske.sk [Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice (Slovakia); Medvecky, L.; Giretova, M.; Stulajterova, R.; Durisin, J. [Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice (Slovakia); Girman, V. [Institute of Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9, 04001 Kosice (Slovakia); Faberova, M. [Institute of Materials Research of SAS, Watsonova 47, 04001 Kosice (Slovakia)

    2016-07-15

    The composite cement mixtures were prepared by mixing brushite (B) with, the amorphous hydrated calcium silicate phosphate (CSPH) or annealed calcium silicate phosphate (CSP composed of Si-saturated hydroxyapatite, wollastonite and silica) phases and water as liquid component. The contents of the silicate-phosphate phase in composites were 10.30 and 50 wt%. The significant effect of both the Ca/P ratio and different solubility of calcium silicate phosphate component in starting cement systems on setting time and phase composition of the final composite cements was demonstrated. The compressive strength of the set cements increased with the filler addition and the highest value (~ 48 MPa) exhibited the 50CSP/B cement composite. The final setting times of the composite cements decreased with the CSPH addition from about 25 to 17 min in 50CSHP/B and setting time of CSP/B composites was around 30 min. The higher content of silica in cements caused the precipitation of fine hydroxyapatite particles in the form of nanoneedles or thin plates perpendicularly oriented to sample surface. The analysis of in vitro cement cytotoxicity demonstrated the strong reduction in cytotoxicity of 10CSPH/B composite with time of cultivation (a low cytotoxicity after 9 days of culture) contrary to cements with higher calcium silicate-phosphate content. These results were attributed to the different surface topography of composite substrates and possible stimulation of cell proliferation by the slow continuously release of ions from 10CSPH/B cement. - Highlights: • Ca/P ratio and solubility of calcium silicate-phosphate components affect the self-setting properties of cements. • Strong relationship between the composite in vitro cytotoxicity and surface microtopography was demonstrated. • Plate-like morphology of coarser particles allowed cells to better adhere and proliferate as compared with nanoneedles.

  16. Investigation on the effects of combining lime and sodium silicate for ...

    African Journals Online (AJOL)

    Expansive clay is unsuitable subgrade material covering about 40% of the area of Ethiopia. Engineering properties of such problematic soils can be improved by chemical stabilization. This study investigated the effects of combining slightly alkaline liquid sodium silicate with hydrated lime for stabilization of expansive clay.

  17. Effects of polymer intercalation in calcium silicate hydrates on drug loading capacities and drug release kinetics: an X-ray absorption near edge structure study

    National Research Council Canada - National Science Library

    Guo, Xiaoxuan; Zhu, Ying-Jie; Hu, Yongfeng; Wu, Jin; Yiu, Yun-Mui; Sham, Tsun-Kong

    2017-01-01

    Different calcium silicate hydrate (CSH)/polymer composites are synthesized by using a controlled precipitation reaction between calcium salt and silicate salt, followed by the addition of various polymer solutions at room temperature...

  18. Analysis of the color alteration and radiopacity promoted by bismuth oxide in calcium silicate cement.

    Science.gov (United States)

    Marciano, Marina Angélica; Estrela, Carlos; Mondelli, Rafael Francisco Lia; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro

    2013-01-01

    The aim of the study was to determine if the increase in radiopacity provided by bismuth oxide is related to the color alteration of calcium silicate-based cement. Calcium silicate cement (CSC) was mixed with 0%, 15%, 20%, 30% and 50% of bismuth oxide (BO), determined by weight. Mineral trioxide aggregate (MTA) was the control group. The radiopacity test was performed according to ISO 6876/2001. The color was evaluated using the CIE system. The assessments were performed after 24 hours, 7 and 30 days of setting time, using a spectrophotometer to obtain the ΔE, Δa, Δb and ΔL values. The statistical analyses were performed using the Kruskal-Wallis/Dunn and ANOVA/Tukey tests (pbismuth oxide was added showed radiopacity corresponding to the ISO recommendations (>3 mm equivalent of Al). The MTA group was statistically similar to the CSC/30% BO group (p>0.05). In regard to color, the increase of bismuth oxide resulted in a decrease in the ΔE value of the calcium silicate cement. The CSC group presented statistically higher ΔE values than the CSC/50% BO group (pbismuth oxide has no relation to the color alteration of calcium silicate-based cements.

  19. Porosity distribution in root canals filled with gutta percha and calcium silicate cement

    NARCIS (Netherlands)

    Moinzadeh, A.T.; Zerbst, W.; Boutsioukis, C.; Shemesh, H.; Zaslansky, P.

    2015-01-01

    Objective Gutta percha is commonly used in conjunction with a sealer to produce a fluid-tight seal within the root canal fillings. One of the most commonly used filling methods is lateral compaction of gutta percha coupled with a sealer such as calcium silicate cement. However, this technique may

  20. Calcium-silicate mesoporous nanoparticles loaded with chlorhexidine for both anti- Enterococcus faecalis and mineralization properties.

    Science.gov (United States)

    Fan, Wei; Li, Yanyun; Sun, Qing; Ma, Tengjiao; Fan, Bing

    2016-10-21

    In infected periapical tissues, Enterococcus faecalis is one of the most common dominant bacteria. Chlorhexidine has been proved to show strong antibacterial ability against E. faecalis but is ineffective in promoting mineralization for tissues around root apex. Mesoporous calcium-silicate nanoparticles are newly synthesized biomaterials with excellent ability to promote mineralization and carry-release bioactive molecules in a controlled manner. In this study, mesoporous calcium-silicate nanoparticles were functionalized with chlorhexidine and their releasing profile, antibacterial ability, effect on cell proliferation and in vitro mineralization property were evaluated. The chlorhexidine was successfully incorporated into mesoporous calcium-silicate nanoparticles by a mixing-coupling method. The new material could release chlorhexidine as well as Ca(2+) and SiO3(2-) in a sustained manner with an alkaline pH value under different conditions. The antimicrobial ability against planktonic E. faecalis was dramatically improved after chlorhexidine incorporation. The nanoparticles with chlorhexidine showed no negative effect on cell proliferation with low concentrations. On dentin slices, the new synthesized material demonstrated a similar inhibitory effect on E. faecalis as the chlorhexidine. After being immersed in SBF for 9 days, numerous apatite crystals could be observed on surfaces of the material tablets. Mesoporous calcium-silicate nanoparticles loaded with chlorhexidine exhibited release of ions and chlorhexidine, low cytotoxicity, excellent antibacterial ability and in vitro mineralization. This material could be developed into a new effective intra-canal medication in dentistry or a new bone defect filling material for infected bone defects.

  1. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Na; Li, Hongxu [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China); Zhao, Yazhao [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Xiaoming, E-mail: liuxm@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Beijing Key Laboratory of Rare and Precious Metals Green Recycling and Extraction, University of Science and Technology Beijing, Beijing 100083 (China)

    2016-04-05

    Highlights: • Cementitious material was designed according to [SiO{sub 4}] polymerization degree of raw materials. • The cementitious material composed of calcium silicate slag yields excellent physical and mechanical properties. • Amorphous C–A–S–H gel and rod-like ettringite are predominantly responsible for the strength development. • Leaching toxicity and radioactivity tests show the cementitious material is environmentally acceptable. - Abstract: Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al{sub 2}O{sub 3} from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C–A–S–H gel, rod-like ettringite and hexagonal-sheet Ca(OH){sub 2} with small amount of zeolite-like minerals such as CaAl{sub 2}Si{sub 2}O{sub 8}·4H{sub 2}O and Na{sub 2}Al{sub 2}Si{sub 2}O{sub 8}·H{sub 2}O. As the predominant hydration products, rod-like ettringite and amorphous C–A–S–H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

  2. Intrinsic differences in atomic ordering of calcium (alumino)silicate hydrates in conventional and alkali-activated cements

    Energy Technology Data Exchange (ETDEWEB)

    White, Claire E., E-mail: whitece@princeton.edu [Department of Civil and Environmental Engineering, Princeton University, Princeton (United States); Andlinger Center for Energy and the Environment, Princeton University, Princeton (United States); Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos (United States); Physics and Chemistry of Materials, Los Alamos National Laboratory, Los Alamos (United States); Daemen, Luke L.; Hartl, Monika; Page, Katharine [Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos (United States)

    2015-01-15

    The atomic structures of calcium silicate hydrate (C–S–H) and calcium (–sodium) aluminosilicate hydrate (C–(N)–A–S–H) gels, and their presence in conventional and blended cement systems, have been the topic of significant debate over recent decades. Previous investigations have revealed that synthetic C–S–H gel is nanocrystalline and due to the chemical similarities between ordinary Portland cement (OPC)-based systems and low-CO{sub 2} alkali-activated slags, researchers have inferred that the atomic ordering in alkali-activated slag is the same as in OPC–slag cements. Here, X-ray total scattering is used to determine the local bonding environment and nanostructure of C(–A)–S–H gels present in hydrated tricalcium silicate (C{sub 3}S), blended C{sub 3}S–slag and alkali-activated slag, revealing the large intrinsic differences in the extent of nanoscale ordering between C–S–H derived from C{sub 3}S and alkali-activated slag systems, which may have a significant influence on thermodynamic stability, and material properties at higher length scales, including long term durability of alkali-activated cements.

  3. Scientific Opinion on the safety evaluation of the active substances, sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate, bentonite, sodium chloride, sodium carbonate for use in active food contact materials

    OpenAIRE

    EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF)

    2013-01-01

    This scientific opinion of the Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety evaluation of the powder mixture of the active substances sodium carbonate peroxyhydrate coated with sodium carbonate and sodium silicate (FCM substance No 1009), bentonite (CAS No 1302-78-9, FCM No 393), sodium chloride (CAS No 7647-14-5, FCM No 985), sodium carbonate (CAS No 497-19-8, FCM No 1008) which are intended to be used as combined oxygen generator and carbon...

  4. Productivity and nutritive value of bluestem grass fertilized with calcium and magnesium silicate

    Directory of Open Access Journals (Sweden)

    Cinthya Souza Santana

    2016-01-01

    Full Text Available This study evaluated the effect of application of calcium and magnesium silicate on the productivity, chemical composition and in situ ruminal degradation of bluestem grass (Andropogon gayanus Kunth, cv. Baeti; Embrapa 23 during the rainy and dry seasons. The design consisted of completely randomized blocks in a 6x2 factorial scheme (six silicate doses and two cutting seasons, arranged in plots subdivided over time. The plots were the calcium and magnesium silicate doses (0, 200, 400, 600, 800 and 1,000 kg/ha and the subplots were the two cutting seasons (rainy and dry period, with five repetitions (blocks. The calcium and magnesium silicate doses exerted no significant effect on green or dry matter production, chemical forage composition or degradability parameters. On the other hand, there was an effect of cutting period on forage production and chemical composition. The highest production of green and dry matter was observed during the rainy period, while acid detergent fiber content was higher during the dry season. The treatments did not exert any significant effect on the parameters of degradability that would alter the nutritive value of bluestem grass.

  5. Fractoemission from fused silica and sodium silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dickinson, J.T.; Langford, S.C.; Jensen, L.C.; McVay, G.L.; Kelso, J.F.; Pantano, C.G.

    1988-05-01

    Fractoemission is the emission of photons and particles due to the fracture of materials. In this paper we present characteristic intensity versus time measurements of photon emission (phE), electron emission (EE), positive ion emission (PIE), and neutral emission (NE) due to the fracture of fused silica and sodium trisilicate glass. We show, for example, that the trisilicate is a copious emitter of atomic Na and both atomic and molecular oxygen. The phE, EE, and PIE from the two glasses share a number of properties.

  6. 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.

  7. Incorporation of bitumen and calcium silicate in cement and lime stabilized soil blocks

    Science.gov (United States)

    Kwan, W. H.; Cheah, C. B.; Ramli, M.; Al-Sakkaf, Y. K.

    2017-04-01

    Providing affordable housing is the most critical problem in many of the developing countries. Using earth materials in building construction is one of the feasible methods to address this issue and it can be a way towards sustainable construction as well. However, the published information on the stabilized soil blocks is limited. Therefore, the present study is conducted to examine the characterization of the soils and engineering properties of the stabilized soil blocks. Four types of stabilizer were used in the study, namely; cement, slaked lime, bitumen emulsion and calcium silicate. Cement and slaked lime were added at different percentages in the range of 5% to 15%, with interval of 2.5%. The percentage was determined based on weight of soil. Meanwhile, bitumen emulsion and calcium silicate were incorporated at various percentages together with 10% of cement. Dosage of bitumen emulsion is in the range of 2% to 10% at interval of 2% while calcium silicate was incorporated at 0.50%, 0.75%, 1.00%, 1.25%, 1.50% and 2.00%. Results show that cement is the most viable stabilizer for the soil block among all stabilizers in this study. The bulk density, optimum moisture content and compressive strengths were increased with the increasing cement content. The most suitable cement content was 10% added at moisture content of 12%. Lime, bitumen and calcium contents were recommended at 5.0%, 6.0% and 1.25%, respectively.

  8. Calcined clay lightweight ceramics made with wood sawdust and sodium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Santis, Bruno Carlos de; Rossignolo, Joao Adriano, E-mail: desantis.bruno@gmail.com [Universidade de Sao Paulo (USP), Pirassununga, SP (Brazil); Morelli, Marcio Raymundo [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

    2016-11-15

    This paper aims to study the influence of including wood sawdust and sodium silicate in the production process of calcined clay lightweight ceramics. In the production process first, a sample used by a company that produces ceramic products in Brazil was collected. The sample was analysed by techniques of liquidity (LL) and plasticity (LP) limits, particle size analysis, specific mass, X-ray diffraction (XRD) and X ray fluorescence spectrometry (XRF). From the clay, specimens of pure clay and mixtures with wood sawdust (10%, 20% and 30% by mass) and sodium silicate were produced and fired at a temperature of 900 deg C. These specimens were submitted to tests of water absorption, porosity, specific mass and compressive strength. Results of this research indicate that the incorporation of wood sawdust and sodium silicate in the ceramic paste specimens can be useful to make calcined clay lightweight ceramics with special characteristics (low values of water absorption and specific mass and high values of compressive strength), which could be used to produce calcined clay lightweight aggregates to be used in structural concrete. (author)

  9. Correlative micro-Raman/EPMA analysis of the hydraulic calcium silicate cement interface with dentin.

    Science.gov (United States)

    Li, Xin; Pongprueksa, Pong; Van Landuyt, Kirsten; Chen, Zhi; Pedano, Mariano; Van Meerbeek, Bart; De Munck, Jan

    2016-09-01

    This study aims to characterize the chemical interplay of hydraulic calcium silicate cements at dentin. Class I cavities were prepared in non-carious human third molars and filled with Biodentine (Septodont) or ProRoot MTA (Dentsply). After 1-day, 1-week, and 1-month Dulbecco's phosphate-buffered saline (DPBS) storage, the specimens were cross-sectioned perpendicular to the cement-dentin interface. The interfaces were evaluated using micro-Raman (μRaman) spectroscopy and at a higher spatial resolution using field emission gun electron probe microanalysis (Feg-SEM/EPMA). μRaman spectroscopy revealed the formation of a transition zone at the interface of both Biodentine (Septodont) and ProRoot MTA (Dentsply) with dentin, having an average thickness of, respectively, 7.5 ± 4.2 and 6.2 ± 5.4 μm, which however was not statistically different. No difference in interfacial ultrastructure and chemistry was found using μRaman spectroscopy between 1 day, 1 week, and 1 month DPBS-stored specimens. The observation of a transition zone at the cement-dentin interfaces contrasts with the EPMA data that revealed a sharper transition from cement to dentin. Again, no difference in interfacial ultrastructure and chemistry was found for different storage periods, with the exception of one 1 month DPBS-stored specimen prepared using Biodentine (Septodont). More specifically, EPMA revealed a gap of about 10-μm wide in the latter specimen that was filled up with newly formed calcium phosphate depositions. Up to 1 month, the interaction of hydraulic calcium silicate cements investigated did not reveal ultrastructural or chemical changes at unaffected dentin with the exception of a calcium phosphate gap-filling property. Hydraulic calcium silicate cements were found to fill gaps by calcium phosphate deposition, however, without conducting chemical changes to the adjacent dentin.

  10. Nanoscale Charge Balancing Mechanism in Alkali Substituted Calcium-Silicate-Hydrate Gels

    CERN Document Server

    Özçelik, V Ongun

    2016-01-01

    Alkali-activated materials and related alternative cementitious systems are sustainable material technologies that have the potential to substantially lower CO$_2$ emissions associated with the construction industry. However, the impact of augmenting the chemical composition of the material on the main binder phase, calcium-silicate-hydrate gel, is far from understood, particularly since this binder phase is disordered at the nanoscale. Here, we reveal the presence of a charge balancing mechanism at the molecular level, which leads to stable structures when alkalis (i.e., Na or K) are incorporated into a calcium-silicate-hydrate gel, as modeled using crystalline 14{\\AA} tobermorite. These alkali containing charge balanced structures possess superior mechanical properties compared to their charge unbalanced counterparts. Our results, which are based on first-principles simulations using density functional theory, include the impact of charge balancing on the optimized geometries of the new model phases, format...

  11. Water transport in the nano-pore of the calcium silicate phase: reactivity, structure and dynamics.

    Science.gov (United States)

    Hou, Dongshuai; Li, Zongjin; Zhao, Tiejun; Zhang, Peng

    2015-01-14

    Reactive force field molecular dynamics was utilized to simulate the reactivity, structure and dynamics of water molecules confined in calcium-silicate-hydrate (C-S-H) nano-pores of 4.5 nm width. Due to the highly reactive C-S-H surface, hydrolytic reactions occur in the solid-liquid interfacial zone, and partially surface adsorbed water molecules transforming into the Si-OH and Ca-OH groups are strongly embedded in the C-S-H structure. Due to the electronic charge difference, the silicate and calcium hydroxyl groups have binomial distributions of the dipolar moment and water orientation. While Ca-OH contributes to the Ow-downward orientation, the ONB atoms in the silicate chains prefer to accept H-bonds from the surface water molecules. Furthermore, the defective silicate chains and solvated Caw atoms near the surface contribute to the glassy nature of the surface water molecules, with large packing density, pronounced orientation preference, and distorted organization. The stable H-bonds connected with the Ca-OH and Si-OH groups also restrict the mobility of the surface water molecules. The significant reduction of the diffusion coefficient matches well with the experimental results obtained by NMR, QENS and PCFR techniques. Upon increasing the distance from the channel, the structural and dynamic behavior of the water molecules varies and gradually translates into bulk water properties at distances of 10-15 Å from the liquid-solid interface.

  12. Effects of Calcium Lignosulfonate and Silicic Acid on Ammonium Nitrate Degradation

    Directory of Open Access Journals (Sweden)

    Ahmet Ozan Gezerman

    2014-01-01

    Full Text Available Ammonium nitrate salts are the most commonly used nitrogenous fertilizers in industry. However, storage of ammonium nitrate is problematic, since its initial properties can decline because of environmental factors, leading to large economic losses. In this study, in order to prevent the caking and degradation of ammonium nitrate, an alternative composition with additional calcium lignosulfonate and silicic acid was studied. The resulting fertilizer was analyzed by screening analysis, ion chromatography, and electron microscopy methods.

  13. Analysis of the color alteration and radiopacity promoted by bismuth oxide in calcium silicate cement

    Directory of Open Access Journals (Sweden)

    Marina Angelica Marciano

    2013-07-01

    Full Text Available The aim of the study was to determine if the increase in radiopacity provided by bismuth oxide is related to the color alteration of calcium silicate-based cement. Calcium silicate cement (CSC was mixed with 0%, 15%, 20%, 30% and 50% of bismuth oxide (BO, determined by weight. Mineral trioxide aggregate (MTA was the control group. The radiopacity test was performed according to ISO 6876/2001. The color was evaluated using the CIE system. The assessments were performed after 24 hours, 7 and 30 days of setting time, using a spectrophotometer to obtain the ΔE, Δa, Δb and ΔL values. The statistical analyses were performed using the Kruskal-Wallis/Dunn and ANOVA/Tukey tests (p 3 mm equivalent of Al. The MTA group was statistically similar to the CSC / 30% BO group (p > 0.05. In regard to color, the increase of bismuth oxide resulted in a decrease in the ΔE value of the calcium silicate cement. The CSC group presented statistically higher ΔE values than the CSC / 50% BO group (p < 0.05. The comparison between 24 hours and 7 days showed higher ΔE for the MTA group, with statistical differences for the CSC / 15% BO and CSC / 50% BO groups (p < 0.05. After 30 days, CSC showed statistically higher ΔE values than CSC / 30% BO and CSC / 50% BO (p < 0.05. In conclusion, the increase in radiopacity provided by bismuth oxide has no relation to the color alteration of calcium silicate-based cements.

  14. Cytotoxicity and genotoxicity of calcium silicate-based cements on an osteoblast lineage

    Directory of Open Access Journals (Sweden)

    Ana Lívia GOMES-CORNÉLIO

    2016-01-01

    Full Text Available Abstract Several calcium silicate-based biomaterials have been developed in recent years, in addition to Mineral Trioxide Aggregate (MTA. The aim of this study was to evaluate the cytotoxicity, genotoxicity and apoptosis/necrosis in human osteoblast cells (SAOS-2 of pure calcium silicate-based cements (CSC and modified formulations: modified calcium silicate-based cements (CSCM and three resin-based calcium silicate cements (CSCR1 (CSCR 2 (CSCR3. The following tests were performed after 24 hours of cement extract exposure: methyl-thiazolyl tetrazolium (MTT, apoptosis/necrosis assay and comet assay. The negative control (CT- was performed with untreated cells, and the positive control (CT+ used hydrogen peroxide. The data for MTT and apoptosis were submitted to analysis of variance and Bonferroni’s posttest (p < 0.05, and the data for the comet assay analysis, to the Kruskal-Wallis and Dunn tests (p < 0.05. The MTT test showed no significant difference among the materials in 2 mg/mL and 10 mg/mL concentrations. CSCR3 showed lower cell viability at 10 mg/mL. Only CSC showed lower cell viability at 50 mg/mL. CSCR1, CSCR2 and CSCR3 showed a higher percentage of initial apoptosis than the control in the apoptosis test, after 24 hours exposure. The same cements showed no genotoxicity in the concentration of 2 mg/mL, with the comet assay. CSC and CSCR2 were also not genotoxic at 10 mg/mL. All experimental materials showed viability with MTT. CSC and CSCR2 presented a better response to apoptosis and genotoxicity evaluation in the 10 mg/mL concentration, and demonstrated a considerable potential for use as reparative materials.

  15. Nanostructural Deformation Analysis of Calcium Silicate Hydrate in Portland Cement Paste by Atomic Pair Distribution Function

    OpenAIRE

    Suzuki, Hiroshi; Bae, Sungchul; Kanematsu, Manabu

    2016-01-01

    The deformation of nanostructure of calcium silicate hydrate (C-S-H) in Portland cement (PC) paste under compression was characterized by the atomic pair distribution function (PDF), measured using synchrotron X-ray diffraction. The PDF of the PC paste exhibited a unique deformation behavior for a short-range order below 2.0 nm, close to the size of the C-S-H globule, while the deformation for a long-range order was similar to that of a calcium hydroxide phase measured by Bragg peak shift. Th...

  16. Reactive molecular simulation on the calcium silicate hydrates/polyethylene glycol composites

    Science.gov (United States)

    Zhou, Yang; Hou, Dongshuai; Jiang, Jinyang; She, Wei; Yu, Jiao

    2017-11-01

    Calcium silicate hydrates (C-S-H) may potentially exhibit extraordinary performance when modified by polymers, in which way the properties of cement-based materials can be improved from the genetic level. In this molecular dynamics simulation of the interaction between C-S-H and polyethylene glycol, apart from the H bond network connection in the interface, another chemical adsorption was observed. Calcium of C-S-H broke the Csbnd O bond of PEG and formed a new Casbnd C connection, which created a stronger link between the organic and inorganic phases.

  17. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2013-01-01

    Full Text Available This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH based on the calcium oxide/polyethylene glycol (CaO/PEG2000 composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET, and Fourier transformed infrared spectroscopy (FT-IR. The reactivity of silica materials (SiO2 enhanced by increasing pH value. Ca2+ could not sustain release from CaO/PEG2000 and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+ and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.

  18. Rapid hydrothermal flow synthesis and characterisation of carbonate- and silicate-substituted calcium phosphates.

    Science.gov (United States)

    Chaudhry, Aqif A; Knowles, Jonathan C; Rehman, Ihtesham; Darr, Jawwad A

    2013-09-01

    A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising phase pure carbonated hydroxyapatite (CO₃-HA) with ≈5 wt% substituted carbonate content (sample 7.5CO₃-HA) and it was found that a further increase in urea concentration in solution resulted in biphasic mixtures of carbonate-substituted hydroxyapatite and calcium carbonate. Transmission electron microscopy images revealed that the particle size of hydroxyapatite decreased with increasing urea concentration. Energy-dispersive X-ray spectroscopy result revealed a calcium deficient apatite with Ca:P molar ratio of 1.45 (±0.04) in sample 7.5CO₃-HA. For silicate-substituted hydroxyapatite (SiO₄-HA) silicon acetate was used as a silicate ion source. It was observed that a substitution threshold of ∼1.1 wt% exists for synthesis of SiO₄-HA in the continuous hydrothermal flow synthesis system, which could be due to the decreasing yields with progressive increase in silicon acetate concentration. All the as-precipitated powders (without any additional heat treatments) were analysed using techniques including Transmission electron microscopy, X-ray powder diffraction, Differential scanning calorimetry, Thermogravimetric analysis, Raman spectroscopy and Fourier transform infrared spectroscopy.

  19. Vibrational investigation of calcium-silicate cements for endodontics in simulated body fluids

    Science.gov (United States)

    Taddei, Paola; Modena, Enrico; Tinti, Anna; Siboni, Francesco; Prati, Carlo; Gandolfi, Maria Giovanna

    2011-05-01

    Calcium-silicate MTA (Mineral Trioxide Aggregate) cements have been recently developed for oral and endodontic surgery. This study was aimed at investigating commercial (White ProRoot MTA, White and Grey MTA-Angelus) and experimental (wTC-Bi) accelerated calcium-silicate cements with regards to composition, hydration products and bioactivity upon incubation for 1-28 days at 37 °C, in Dulbecco's Phosphate Buffered Saline (DPBS). Deposits on the surface of the cements and the composition changes during incubation were investigated by micro-Raman and ATR/FT-IR spectroscopy, and pH measurements. Vibrational techniques disclosed significant differences in composition among the unhydrated cements, which significantly affected the bioactivity as well as pH, and hydration products of the cements. After one day in DPBS, all the cements were covered by a more or less homogeneous layer of B-type carbonated apatite. The experimental cement maintained a high bioactivity, only slightly lower than the other cements and appears a valid alternative to commercial cements, in view of its adequate setting time properties. The bioactivity represents an essential property to favour bone healing and makes the calcium-silicate cements the gold standard materials for root-apical endodontic surgery.

  20. Influence De La Gestation Sur Les Taux De Calcium, Sodium ...

    African Journals Online (AJOL)

    calcium (Ca), sodium (Na), potassium (K) and magnesium (Mg). The quantity of minerals in the serum of individual sow was determined by atomic absorption spectrophotometer. The level of studied minerals was relatively higher in gravid sows as compared to non gravid. However, the difference was significant only for the ...

  1. Bond strength of a calcium silicate-based sealer tested in bulk or with different main core materials.

    Science.gov (United States)

    Nagas, Emre; Cehreli, Zafer; Uyanik, Mehmet Ozgur; Durmaz, Veli

    2014-01-01

    The aim of this study was to evaluate the influence of a calcium silicate-based sealer (iRoot SP), with or without a core material, on bond strength to radicular dentin, in comparison with various contemporary root filling systems. Root canals of freshly extracted single-rooted teeth (n = 60) were instrumented using rotary instruments. The roots were randomly assigned to one of the following experimental groups: (1) a calcium silicate-based sealer without a core material (bulk-fill); (2) a calcium silicate-based sealer + gutta-percha; (3) a calcium silicate-based sealer + Resilon; (4) a methacrylate resin-based sealer (RealSeal SE) + Resilon; (5) an epoxy resin-based sealer (AH Plus) + gutta-percha, and (6) a mineral trioxide aggregate-based endodontic sealer (MTA Fillapex) + gutta-percha. Four 1-mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength testing was performed at a cross-head speed of 1 mm/min, and the bond strength data were analyzed statistically by one-way analysis of variance and Tukey tests (p core filling materials. When the calcium silicate-based sealer was placed in bulk, its dislocation resistance was similar to that of commonly used sealer + core root filling systems. Thus, the concept of using a calcium silicate-based sealer in bulk can be more easily advocated in clinical practice.

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

    Science.gov (United States)

    2010-04-01

    ... polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. 872.3490 Section 872.3490 Food and Drugs... DENTAL DEVICES Prosthetic Devices § 872.3490 Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive. (a) Identification. A carboxymethylcellulose...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  4. Development of an immobilization process for heavy metal containing galvanic solid wastes by use of sodium silicate and sodium tetraborate

    Energy Technology Data Exchange (ETDEWEB)

    Aydın, Ahmet Alper, E-mail: ahmetalperaydin@gmail.com [Chair of Urban Water Systems Engineering, Technische Universität München, Am Coulombwall, 85748 Garching (Germany); Aydın, Adnan [Istanbul Bilim University, School of Health, Esentepe, Istanbul, Sisli, 34394 (Turkey)

    2014-04-01

    Highlights: • A new physico-chemical process below 1000 °C for immobilization of galvanic sludges. • Sodium tetraborate and sodium silicate have been used as additives. • A strategy for adjustment of solid waste/additive mixture composition is presented. • Strategy is valid for wastes of hydrometallurgical and electro-plating processes. • Lower energy consumption and treated waste volume, shorter process time are provided. - Abstract: Heavy metal containing sludges from wastewater treatment plants of electroplating industries are designated as hazardous waste since their improper disposal pose high risks to environment. In this research, heavy metal containing sludges of electroplating industries in an organized industrial zone of Istanbul/Turkey were used as real-sample model for development of an immobilization process with sodium tetraborate and sodium silicate as additives. The washed sludges have been precalcined in a rotary furnace at 900 °C and fritted at three different temperatures of 850 °C, 900 °C and 950 °C. The amounts of additives were adjusted to provide different acidic and basic oxide ratios in the precalcined sludge-additive mixtures. Leaching tests were conducted according to the toxicity characteristic leaching procedure Method 1311 of US-EPA. X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and flame atomic absorption spectroscopy (FAAS) have been used to determine the physical and chemical changes in the products. Calculated oxide molar ratios in the precalcined sludge-additive mixtures and their leaching results have been used to optimize the stabilization process and to determine the intervals of the required oxide ratios which provide end-products resistant to leaching procedure of US-EPA. The developed immobilization-process provides lower energy consumption than sintering-vitrification processes of glass–ceramics.

  5. The Influence of Silica Module of the Soluble Sodium Silicate Hardened by Ester on the Residual Strenght of Molding Sand

    Directory of Open Access Journals (Sweden)

    Baliński A.

    2013-03-01

    Full Text Available Describes how to obtain a soluble sodium silicate with a density of 1.40 g/cm3, 1.45 g/cm3, 1.50 g/cm3, and silica module M = 2.1 obtained from the silica- sodium glass with module M = 3.3 and M = 2.1. Residual (final strength of molding samples made with these binders, were determined at temperatures corresponding to the characteristic temperatures of phase and temperature transitions of silica gel. Indicated the type of soluble sodium silicate capable of obtain the smallest value of the final strength of molding sand in the specified range of temperatures.

  6. The Influence of Silica Module of the Soluble Sodium Silicate Hardened by Ester on the Residual Strenght of Molding Sand

    Directory of Open Access Journals (Sweden)

    A. Baliński

    2013-01-01

    Full Text Available Describes how to obtain a soluble sodium silicate with a density of 1.40 g/cm3, 1.45 g/cm3, 1.50 g/cm3, and silica module M = 2.1obtained from the silica- sodium glass with module M = 3.3 and M = 2.1. Residual (final strength of molding samples made with thesebinders, were determined at temperatures corresponding to the characteristic temperatures of phase and temperature transitions of silica gel. Indicated the type of soluble sodium silicate capable of obtain the smallest value of the final strength of molding sand in the specified range of temperatures.

  7. EFFECT OF SODIUM SILICATE TO SODIUM HYDROXIDE RATIOS ON DURABILITY OF GEOPOLYMER MORTARS CONTAINING NATURAL AND ARTIFICIAL POZZOLANS

    Directory of Open Access Journals (Sweden)

    F. Nurhayat Degirmenci

    2017-09-01

    Full Text Available This study aims to provide the experimental data on the sulphate and acid performance of geopolymer mortar containing pozzolanic materials such as fly ash (FA, ground granulated blast furnace slag (GGBS and natural zeolite (NZ. The alkaline solution was the combination of sodium silicate and sodium hydroxide solution with the ratio (Na ₂SiO₃/NaOH of 1.0, 2.0 and 3.0. The molarity of sodium hydroxide was fixed as 10. The performances of geopolymer mortar were measured in terms of sodium and magnesium sulphate resistance and sulphuric and hydrochlorich acid resistance with 5% and 10 % concentration after 24 weeks. The evaluations were measured as visual observation, measurement of weight change and residual compressive strength. It has been observed that Na ₂SiO₃/NaOH ratio is effective on residual compressive strength of geopolymer mortar in both sulphate and acid exposure. The higher ratio of Na ₂SiO₃/NaOH results in a higher residual compressive strength. The GGBS based geopolymer mortar has a very good resistance in acid media in terms of weight loss and residual compressive strength. The inclusion of FA in the GGBS based geopolymer mixture was found to be a suitable base of geopolymer mortar under ambient curing conditions.

  8. Attributes of the soil fertilized with sewage sludge and calcium and magnesium silicate

    Directory of Open Access Journals (Sweden)

    Geraldo R. Zuba Junio

    2015-11-01

    Full Text Available ABSTRACTThis study aimed to evaluate the chemical attributes of an Inceptisol cultivated with castor bean (Ricinus communis L., variety ‘BRS Energia’, fertilized with sewage sludge compost and calcium (Ca and magnesium (Mg silicate. The experiment was conducted at the ICA/UFMG, in a randomized block design, using a 2 x 4 factorial scheme with three replicates, and the treatments consisted of two doses of Ca-Mg silicate (0 and 1 t ha-1 and four doses of sewage sludge compost (0, 23.81, 47.62 and 71.43 t ha-1, on dry basis. Soil organic matter (OM, pH, sum of bases (SB, effective cation exchange capacity (CEC(t, total cation exchange capacity (CEC(T, base saturation (V% and potential acidity (H + Al were evaluated. There were no significant interactions between doses of sewage sludge compost and doses of Ca-Mg silicate on soil attributes, and no effect of silicate fertilization on these attributes. However, fertilization with sewage sludge compost promoted reduction in pH and increase in H + Al, OM and CEC. The dose of 71.43 t ha-1 of sewage sludge compost promoted the best soil chemical conditions.

  9. EFFECT OF ACID CONCENTRATION ON CHARACTERS OF SILICA GEL SYNTHESIZED FROM SODIUM SILICATE

    Directory of Open Access Journals (Sweden)

    Nuryono Nuryono

    2010-06-01

    Full Text Available In this research, synthesis and characterization of silica gel from sodium silicate through sol-gel process using H2SO4, HCl, and citric acid have been investigated. Synthesis was carried out by mixing and stirring  20 mL of H2SO4, HCl or citric acid  at certain concentration with 50 mL of sodium silicate solution (Na2O 0.17 M and SiO2 0.61 M for one hour and let to form gel.  The gel was washed with distillated water, and dried in an oven at 100 oC. Characterization of silica gel was carried out by determination of acidity, water adsorption capacity, and water content. Identification of functional group and structure were identified using x-ray diffractometer (XRD and infrared (IR spectrophotometer, respectively.  Results showed that at a range of investigated concentration (0.6 - 3.0 M the increase of concentration, formation of gel with H2SO4 tended to be faster, but with HCl and citric acid to be slower. The increase of acid concentration caused water content, water adsorption capacity, and acidity of the silica gel resulted with HCl and citric acid tended to be increased, increased, and increased, but with H2SO4 to be decreased, increased, and decreased, respectively. Based on the IR spectra and XRD data, it could concluded that the synthetic silica gels contained silanol (Si-OH and siloxane (Si-O-Si and were amorphous, showing similar pattern to kieselgel G 60 produced by Merck.   Keywords: silica gel, adsorption capacity, sodium silicate, acidity

  10. Dentine-pulp tissue engineering in miniature swine teeth by set calcium silicate containing bioactive molecules.

    Science.gov (United States)

    Tziafas, Dimitrios; Kodonas, Konstantinos; Gogos, Christos; Tziafa, Christina; Papadimitriou, Seraphim

    2017-01-01

    The present study aims to investigate whether reparative dentinogenesis could be guided at central pulpal sites or at a distance from the amputated pulp of miniature pig teeth, by using set calcium silicate-based carriers containing human recombinant bioactive molecules. Pulp exposures were performed in 72 permanent teeth of 4 healthy miniature swine. The teeth were capped with pre-manufactured implants of set calcium silicate-based material containing BMP-7, TGFβ1 or WnT-1, for 3 weeks. Conical-shaped intrapulpal implants were exposed in the central pulp core, while disc-shaped extrapulpal implants were placed at a distance from the amputated pulp. Implants without bioactive molecules were used as controls. Thickness and forms of new matrix mineralized deposition were assessed histologically at post-operative periods of 3 weeks by light microscopy. Intrapulpal applications: Calcified structures composed of osteodentine were found in contact with the BMP-7 implants. An inhomogeneous calcified tissue matrix was found around the WnT-1 carriers. A two-zone calcified structure composed of osteodentine and a thicker tubular matrix zone was seen at the TGFβ1 carrier-pulp interface. Extrapulpal applications: The space between WnT-1 implants and pulp periphery had been invaded by soft tissue with traces of calcified foci. Thick calcified structures composed of osteodentine were found surrounding pulp exposure sites in response to application of BMP-7. Spindle-shaped cells associated with atubular calcified matrix or elongated polarized cells associated with tubular dentine-like matrix were found along the cut dentinal walls of the TGFβ1 group. The present experiments indicated that set calcium silicate could be used as carrier for biologically active molecules. TGFβ1 was shown to be an effective bioactive molecule in guiding tertiary dentine formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Biocompatibility of a new nanomaterial based on calcium silicate implanted in subcutaneous connective tissue of rats

    Directory of Open Access Journals (Sweden)

    Petrović Violeta

    2012-01-01

    Full Text Available The aim of the study was to investigate rat connective tissue response to a new calcium silicate system 7, 15, 30 and 60 days after implantation. Twenty Wistar albino male rats received two tubes half-filled with a new calcium silicate system (NCSS or MTA in subcutaneous tissue. The empty half of the tubes served as controls. Five animals were sacrificed after 7, 15, 30 and 60 days and samples of the subcutaneous tissue around implanted material were submitted to histological analysis. The intensity of inflammation was evaluated based on the number of inflammatory cells present. Statistical analysis was performed using one way ANOVA and Holm Sidak's multiple comparison tests. Mild to moderate inflammatory reaction was observed after 7, 15 and 30 days around a NCSS while mild inflammatory reaction was detected after 60 days of implantation. In the MTA group, mild to moderate inflammatory reaction was found after 7 and 15 days while mild inflammatory reaction was present after 30 and 60 days. There was no statistically significant difference in the intensity of inflammatory reactions between the tested materials and control groups in any experimental period (ANOVA p>0.05. Regarding the intensity of inflammatory reactions at different experimental periods, a statistically significant difference was observed between 7 and 30 days, 7 and 60 days and 15 to 60 days for both materials. For the controls, a statistically significant difference was found between 7 and 60 days and 15 and 60 days of the experiment (Holm Sidak < p 0.001. Subcutaneous tissue of rats showed good tolerance to a new calcium silicate system. Inflammatory reaction was similar to that caused by MTA. [Projekat Ministarstva nauke Republike Srbije, br. 172026

  12. Rapid hydrothermal flow synthesis and characterisation of carbonate- and silicate-substituted calcium phosphates

    Science.gov (United States)

    Knowles, Jonathan C; Rehman, Ihtesham; Darr, Jawwad A

    2013-01-01

    A range of crystalline and nano-sized carbonate- and silicate-substituted hydroxyapatite has been successfully produced by using continuous hydrothermal flow synthesis technology. Ion-substituted calcium phosphates are better candidates for bone replacement applications (due to improved bioactivity) as compared to phase-pure hydroxyapatite. Urea was used as a carbonate source for synthesising phase pure carbonated hydroxyapatite (CO3-HA) with ≈5 wt% substituted carbonate content (sample 7.5CO3-HA) and it was found that a further increase in urea concentration in solution resulted in biphasic mixtures of carbonate-substituted hydroxyapatite and calcium carbonate. Transmission electron microscopy images revealed that the particle size of hydroxyapatite decreased with increasing urea concentration. Energy-dispersive X-ray spectroscopy result revealed a calcium deficient apatite with Ca:P molar ratio of 1.45 (±0.04) in sample 7.5CO3-HA. For silicate-substituted hydroxyapatite (SiO4-HA) silicon acetate was used as a silicate ion source. It was observed that a substitution threshold of ∼1.1 wt% exists for synthesis of SiO4-HA in the continuous hydrothermal flow synthesis system, which could be due to the decreasing yields with progressive increase in silicon acetate concentration. All the as-precipitated powders (without any additional heat treatments) were analysed using techniques including Transmission electron microscopy, X-ray powder diffraction, Differential scanning calorimetry, Thermogravimetric analysis, Raman spectroscopy and Fourier transform infrared spectroscopy. PMID:22983020

  13. A novel pharmaceutical excipient: Coprecipitation of calcium and magnesium silicate using brine-seawater in date palm cellulose as an absorbing host

    Directory of Open Access Journals (Sweden)

    Mohammad Hamaidi

    2017-09-01

    Full Text Available This research aims to produce a cost competitive and innovative pharmaceutical additive with multi-purpose use in the pharmaceutical industry from Saudi Arabia natural resources and bio-wastes. The waste substance, brine, and the naturally occurring compound, sodium silica, were reacted together to produce water insoluble calcium and magnesium silicate salts [WISS]. The purity index WISS was compared with synthetic Mg silicae.The produced particle size was 1.994 µm. Date palm cellulose [DPC] with a high purity index [0.99] was produced from the biomass waste of date palm tree. DPC was used as a host for coprecipitation of synthetic calcium magnesium silicate within its intimate structures. The interaction between the cellulose polymer and silicates is physical in nature. WISS-DPC was more flowable than DPC. In SEM, the particles of DPC were fibrous and irregular in shape, while WISS-DPC showed more regular shape than DPC. Tablets prepared from WISS-DPC were harder and had lower disintegration time at all compression forces compared to those made from DPC. The produced excipient had excellent compaction and disintegration properties and could be used as a superdisintegrant and tablet binder in pharmaceutical industries.

  14. [The treatment of vertebral osteoporosis. Use of sodium fluoride and sodium monofluorophosphate in combination with calcium].

    Science.gov (United States)

    Meunier, P J

    1990-01-15

    The ideal curative treatment of osteoporosis must be capable of raising the trabecular bone mass to its former level, since only a substantial increase in bone mass can reduce the fracture rate of the spine. Fluoride is an effective activator of osteoblasts and thus increases axial bone mass and decreases the vertebral fracture rate. The drawbacks of the formerly used sodium fluoride such as gastrolesivity and its in compatibility with concomitant calcium intake were overcome by using sodium monofluorophosphate (MFP) as the source of fluoride. MFP is well tolerated gastrointestinally and can be used concomitantly with calcium-containing medicaments or with calcium-rich alimentation. Fluoride treatment has proved to be an effective measure against continued progression of osteoporosis, and possible risks present no difficulties. The benefits of this therapy certainly outweigh possible adverse effects.

  15. Microstructure and mechanical properties of stainless steel/calcium silicate composites manufactured by selective laser melting.

    Science.gov (United States)

    Zheng, Zeng; Wang, Lianfeng; Jia, Min; Cheng, Lingyu; Yan, Biao

    2017-02-01

    Selective laser melting (SLM) is raised as one kind of additive manufacturing (AM) which is based on the discrete-stacking concept. This technique can fabricate advanced composites with desirable properties directly from 3D CAD data. In this research, 316L stainless steel (316L SS) and different fractions of calcium silicate (CaSiO3) composites (weight fractions of calcium silicate are 0%, 5%,10% and 15%, respectively) were prepared by SLM technique with a purpose to develop biomedical metallic materials. The relative density, tensile, microhardness and elastic modulus of the composites were tested, their microstructures and fracture morphologies were observed using optical microscope (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the addition of CaSiO3 particles influenced the microstructure and mechanical properties of specimens significantly. The CaSiO3 precipitates from the overlap of adjacent tracks and became the origin of the defects. The tensile strength of specimens range 320-722MPa. The microhardness and elastic modulus are around 250HV and 215GPa respectively. These composites were ductile materials and the fracture mode of the composites was mixed mode of ductile and brittle fracture. The 316L SS/CaSiO3 composites can be a potential biomedical metallic materials in the medical field. Copyright © 2016. Published by Elsevier B.V.

  16. Dynamical behaviors of structural, constrained and free water in calcium- and magnesium-silicate-hydrate gels.

    Science.gov (United States)

    Le, Peisi; Fratini, Emiliano; Ito, Kanae; Wang, Zhe; Mamontov, Eugene; Baglioni, Piero; Chen, Sow-Hsin

    2016-05-01

    The mechanical properties of cement pastes depend strongly on their porosities. In a saturated paste, the porosity links to the free water volume after hydration. Structural water, constrained water, and free water have different dynamical behavior. Hence, it should be possible to extract information on pore system by exploiting the water dynamics. We investigated the slow dynamics of hydration water confined in calcium- and magnesium-silicate-hydrate (C-S-H and M-S-H) gels using high-resolution quasi-elastic neutron scattering (QENS) technique. C-S-H and M-S-H are the chemical binders present in calcium rich and magnesium rich cements. We measured three M-S-H samples: pure M-S-H, M-S-H with aluminum-silicate nanotubes (ASN), and M-S-H with carboxyl group functionalized ASN (ASN-COOH). A C-S-H sample with the same water content (i.e. 0.3) is also studied for comparison. Structural water in the gels contributes to the elastic component of the QENS spectrum, while constrained water and free water contribute the quasi-elastic component. The quantitative analysis suggests that the three components vary for different samples and indicate the variance in the system porosity, which controls the mechanical properties of cement pastes. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Quantitative kinetic and structural analysis of geopolymers. Part 2. Thermodynamics of sodium silicate activation of metakaolin

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zuhua, E-mail: zuhua.zhang2@usq.edu.au [Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, QLD 4350 (Australia); Provis, John L. [Department of Materials Science and Engineering, The University of Sheffield, Mappin St, Sheffield S1 3JD (United Kingdom); Wang, Hao; Bullen, Frank [Faculty of Engineering and Surveying, University of Southern Queensland, Toowoomba, QLD 4350 (Australia); Reid, Andrew [Halok Pty Ltd. West End, QLD 4101 (Australia)

    2013-08-10

    Highlights: • ICC is confirmed again to be useful in studying the thermodynamics of geopolymerization. • Na-silicate activation of metakaolin at 25 °C processes an extent of ∼0.20, far from the final structure. • Na/Al has a more pronounced influence on the reaction extent of metakaolin than do temperature and Si/Al ratio. • ICC is expected to be a powerful technique in quantifying the reactivity of various aluminosilicate precursors. - Abstract: The paper describes the outcomes of a study using isothermal conduction calorimetry (ICC) to characterize the geopolymerization kinetics of metakaolin activated with sodium silicate. Two exothermic peaks are observed in the calorimetric curves for all systems reacting within the temperature range 20–40 °C. The peaks are assigned to the dissolution of metakaolin, and the formation of geopolymeric gels with disordered structure, respectively. Compared with the use of NaOH solution to activate metakaolin, the presence of soluble silicate in the activator hinders the reorganization of the local structure of geopolymeric gels and also suppresses the formation of zeolites or zeolite precursors. The ICC data are used via a thermochemical model to quantify the reaction kinetics of geopolymerization, by assuming that the geopolymeric gels have an analcime-like local structure and taking into account the speciation of the silicate monomers and dimers in the activator. Decreasing the modulus from 1.6 to 1.0 increases the fractional reaction extent from 0.12 to 0.26 after 72 h at 25 °C. When the modulus is 1.2, increasing the reaction temperature from 20 °C to 35 °C results in an improved reaction extent from 0.24 to 0.35. The rapid polymerization that occurs at 40 °C appears to hinder the further reaction of MK and consequently results in a lower reaction extent than at 35 °C. Combined with the findings from previous analysis of systems where NaOH was used to activate MK, the concentration of available Na

  18. BIOPRODUCTION AND CHARACTERIZATION OF SODIUM, POTASSIUM, AND CALCIUM LACTOBIONATES

    Directory of Open Access Journals (Sweden)

    Maria G. Delagustin

    Full Text Available Lactobionic acid and its salts are substances that have several applications in the pharmaceutical area. These products were obtained by bioconversion through the enzymatic complex glucose-fructose-oxidoreductase (GFOR/gluconolactonase (GL present in calcium alginate immobilized cells of Zymomonas mobilis. In the reactions catalyzed by this enzyme system, the medium pH must be controlled at slightly acid values. For this purpose, NaOH, KOH, or Ca(OH2 were used, and as a result, the respective salts were formed. The kinetic study on the formation of sodium, potassium and calcium lactobionates was followed by the steps of purification and characterization aiming the potential use of these compounds in the pharmaceutical area. In the assays for the bioproduction of sodium, potassium or calcium lactobionates, yields of 74, 77 and 84% were obtained, respectively. In the salts purification step, purity levels of approximately 95% were achieved. The structural identities of the lactobionate salts were determined by high resolution mass spectrometry, in addition to the 13C and 1H NMR analysis. The characterization demonstrates the selectivity of the enzymatic reaction of GFOR/GL of Z. mobilis, in the production of lactobionic acid and its salts.

  19. Plasma membrane calcium pump and sodium-calcium exchanger in maintenance and control of calcium concentrations in platelets.

    Science.gov (United States)

    Juska, Alfonsas

    2010-01-29

    The purpose of this research was to elucidate the activity of the mechanisms responsible for control of cytosolic calcium concentration in platelets by modeling the time-course of the concentration changing in response to discharge of the intracellular stores or store-operated calcium entry (SOCE). The parameters estimated as a result of model fitting to experimental data are related to physiological or pathological state of the cells. It has been shown that: (a) the time-course is determined by the passive calcium fluxes and activities of the corresponding mechanisms; (b) the decline in the concentration (after its rise) develops due to activity of plasma membrane calcium ATPase (PMCA) both in the case of discharge of the stores of platelets contained in calcium-free medium and in the case of SOCE; (c) impulsive extrusion of calcium in response to its sudden influx, presumably, is the main function of PMCA; (d) the function of sodium-calcium exchanger (NCX) is to extrude calcium excess by permanent counteracting its influx. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  20. Cytotoxicity and Osteogenic Potential of Silicate Calcium Cements as Potential Protective Materials for Pulpal Revascularization

    Science.gov (United States)

    Bortoluzzi, Eduardo A.; Niu, Li-na; Palani, Chithra D.; El-Awady, Ahmed R.; Hammond, Barry D.; Pei, Dan-dan; Tian, Fu-cong; Cutler, Christopher W.; Pashley, David H.; Tay, Franklin R.

    2016-01-01

    Objectives In pulpal revascularization, a protective material is placed coronal to the blood clot to prevent recontamination and to facilitate osteogenic differentiation of mesenchynal stem cells to produce new dental tissues. Although mineral trioxide aggregate (MTA) has been the material of choice for clot protection, it is easily displaced into the clot during condensation. The present study evaluated the effects of recently-introduced calcium silicate cements (Biodentine and TheraCal LC) on the viability and osteogenic differentiation of human dental pulp stem cells (hDPSCs) by comparing with MTA Angelus. Methods Cell viability was assessed using XTT assay and flow cytometry. The osteogenic potential of hDPSCs exposed to calcium silicate cements was examined using qRT-PCR for osteogeic gene expressions, alkaline phosphatase enzyme activity, Alizarin red S staining and transmission electron microscopy of extracellular calcium deposits. Parametric statistical methods were employed for analyses of significant difference among groups, with α=0.05. Results The cytotoxic effects of Biodentine and TheraCal LC on hDPSCs were time- and concentration-dependent. Osteogenic differentiation of hDPSCs was enhanced after exposure to Biodentine that was depleted of its cytotoxic components. This effect was less readily observed in hDPSCs exposed to TheraCal LC, although both cements supported extracelluar mineralization better than the positive control (zinc oxide-eugenol–based cement). Significance A favorable tissue response is anticipated to occur with the use of Biodentine as a blood clot-protecting material for pulpal revascularizaiton. Further investigations with the use of in vivo animal models are required to validate the potential adverse biological effects of TheraCal LC on hDPSCs. PMID:26494267

  1. Cytotoxicity and osteogenic potential of silicate calcium cements as potential protective materials for pulpal revascularization.

    Science.gov (United States)

    Bortoluzzi, Eduardo A; Niu, Li-Na; Palani, Chithra D; El-Awady, Ahmed R; Hammond, Barry D; Pei, Dan-Dan; Tian, Fu-Cong; Cutler, Christopher W; Pashley, David H; Tay, Franklin R

    2015-12-01

    In pulpal revascularization, a protective material is placed coronal to the blood clot to prevent recontamination and to facilitate osteogenic differentiation of mesenchymal stem cells to produce new dental tissues. Although mineral trioxide aggregate (MTA) has been the material of choice for clot protection, it is easily displaced into the clot during condensation. The present study evaluated the effects of recently introduced calcium silicate cements (Biodentine and TheraCal LC) on the viability and osteogenic differentiation of human dental pulp stem cells (hDPSCs) by comparing with MTA Angelus. Cell viability was assessed using XTT assay and flow cytometry. The osteogenic potential of hDPSCs exposed to calcium silicate cements was examined using qRT-PCR for osteogenic gene expressions, alkaline phosphatase enzyme activity, Alizarin red S staining and transmission electron microscopy of extracellular calcium deposits. Parametric statistical methods were employed for analyses of significant difference among groups, with α=0.05. The cytotoxic effects of Biodentine and TheraCal LC on hDPSCs were time- and concentration-dependent. Osteogenic differentiation of hDPSCs was enhanced after exposure to Biodentine that was depleted of its cytotoxic components. This effect was less readily observed in hDPSCs exposed to TheraCal LC, although both cements supported extracellular mineralization better than the positive control (zinc oxide-eugenol-based cement). A favorable tissue response is anticipated to occur with the use of Biodentine as a blood clot-protecting material for pulpal revascularization. Further investigations with the use of in vivo animal models are required to validate the potential adverse biological effects of TheraCal LC on hDPSCs. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. The study of thermal interaction and microstructure of sodium silicate/bentonite composite under microwave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Subannajui, Kittitat, E-mail: kittitat.sub@mahidol.ac.th [Faculty of Science, Mahidol University, 272 Rama VI Road, Ratchathewi District, Bangkok 10400 (Thailand); Center of Nanoscience and Nanotechnology Research Unit, Mahidol University, 272 Rama VI Road, Ratchathewi District, Bangkok 10400 (Thailand)

    2016-12-01

    The commercial heating oven usually consumes the power around 2500–3000 Watt and the temperature inside the oven is still below 350 °C. If we need to increase a temperature above 500 °C, a special heating setup with a higher power furnace is required. However, in this work, we propose a composite material that interacts with 2.45 GHz 500 Watt microwave and rapidly redeems the thermal energy with the temperature around 600–900 °C. The composite amorphous material easily forms liquid ceramics phase with a high temperature output and responds to the microwave radiation better than that of the solid phase. During the heating process, phase transformation occurs. This method is very effective and can be used to drastically reduce the power consumption of any heating process. - Highlights: • Amorphous phase transforms to liquid phase by microwave radiation. • Pure sodium silicate and pure bentonite cannot show temperature overshoot. • Silicate-bentonite composite shows a high temperature overshoot above 700 °C. • A rapid heating crucible for the annealing application is fabricated.

  3. Experimental Evaluation of Sodium Silicate-Based Nanosilica against Chloride Effects in Offshore Concrete

    Directory of Open Access Journals (Sweden)

    Kyoung-Min Kim

    2014-01-01

    Full Text Available This study investigates the effect of a new pore filling material, named sodium silicate-based nanosilica (SS, on resisting the diffusion of the chloride ions. The proposed SS is chosen, mainly due to its smaller particle size, compared to the conventional ethyl silicate-based nanosilica. Each particle of SS is chemically treated to have the negative (− charge on its surface. Four types of mixes with different amounts of partial replacement with fly ash and slag are prepared. Effect of water to binder ratios (0.35, 0.40, and 0.45 is also examined. Test results showed that the inclusion of SS was significantly beneficial for protecting the concrete from chloride attack. At a given strength, the SS inclusion in concrete was up to three times more effective than the control concrete without SS. It is believed that these excellent results are attributed to the small particle size and the chemical surface treatment of SS. In this study, experiments of compressive strength, hydration heat, accelerated neutralization, and sulfate erosion tests were also conducted to find the general effect of SS inclusion on the fundamental properties and durability of concrete.

  4. Hydrothermal synthesis of meso porous silica MCM-41 using commercial sodium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Melendez O, H. I.; Mercado S, A.; Garcia C, L. A.; Castruita, G.; Perera M, Y A., E-mail: ivan_melendez380@hotmail.com [Centro de Investigacion en Quimica Aplicada, Bldv. Enrique Reyna Hermosillo No. 140, Saltillo 25294, Coahuila (Mexico)

    2013-08-01

    In this work, ordered meso porous silica MCM-41 was prepared by hydrothermal synthesis using industrial-grade sodium silicate (Na{sub 2}SiO{sub 3}) as silica source, hexadecyltrimethyl-ammonium bromide (CTAB) as template agent and ethyl acetate as ph regulator. The influence of CTAB/SiO{sub 2} molar ratio, reaction time, aging temperature, and co-surfactant type on the structural and morphological properties of the obtained silica was studied. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption isotherms. Ordered meso porous MCM-41 silica was obtained at 80 C by using a range of CTAB/SiO{sub 2} molar ratio from 0.35 to 0.71 and reaction times up to 72 h and isopropanol (i-Pr OH) as co-surfactant. (Author)

  5. Hydrothermal Synthesis of SBA-15 Using Sodium Silicate Derived from Coal Gangue

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2013-01-01

    Full Text Available Well-ordered SBA-15 was prepared with a hydrothermal route by sodium silicate derived from coal gangue. The as-prepared sample was analyzed by SAXRD, BET, TEM, and SEM, respectively. The results indicate that at a low hydrothermal temperature of 100∘C the well-ordered mesoporous SBA-15 could be synthesized. The surface area, pore volume, and pore size of the sample are 552 m2/g, 0.54 cm3/g, and 7.0 nm, respectively. It is suggested that coal gangue could be used in obtaining an Si source to prepare mesoporous materials, such as SBA-15.

  6. Effect of Silver Nanoparticles and Sodium Silicate on Vase Life and Quality of Cut Chrysanthemum Dendranthema grandiflorum L. (Flower

    Directory of Open Access Journals (Sweden)

    S. Kazemipour

    2016-02-01

    Full Text Available Dendranthema grandiflorum L. is one of the widely cultivated flowers around the world for producing of cut flowers. Nanometer-sized silver particles are used in various applications as an anti-microbial compound. This experiment was carried out to study the effects of silver nanoparticles (0, 5, 10 and 20 mg/L and sodium silicate (0, 50, 100 and 150 mg/L on longevity and quality of cut chrysanthemum (Dendranthema grandiflorum L. flowers. A factorial experiment was conducted based on randomized complete block design with 16 treatments, 3 replications, 48 plots and 192 cut flowers. The cut flowers were pulsed for 24 h with pulse solutions and then transported to 300 mg L-1 8-hidroxy quinoline sulfate and 3% sucrose. The characteristics such as vase life, loss of fresh weight, number of bacterial colonies in stem, lipid peroxidation, and activity of superoxide dismutase (SOD were measured. Results showed that all treatments had positive effects on the vase life of flowers. Pulse solution with 10 mg/L silver nanoparticles and 100 mg/L sodium silicate and interaction between them, increased vase life compared to the control (3.21, 4.46 and 8.50 days, respectively. In addition, the flowers pulsed with silver nanoparticles and sodium silicate exhibited higher activity of SOD, compared to control. The present study showed that using proper concentrations of silver nanoparticles and sodium silicate can enhance the vase life of cut chrysanthemum flowers.

  7. Characterization of set Intermediate Restorative Material, Biodentine, Bioaggregate and a prototype calcium silicate cement for use as root-end filling materials.

    Science.gov (United States)

    Grech, L; Mallia, B; Camilleri, J

    2013-07-01

    To investigate the composition of materials and leachate of a hydrated prototype cement composed of tricalcium silicate and radiopacifier and compare this to other tricalcium silicate-based cements (Biodentine and Bioaggregate) to assess whether the additives in the proprietary brand cements affect the hydration of the materials, using Intermediate Restorative Material (IRM), a standard root-end filling material as a control. The materials investigated included a prototype-radiopacified tricalcium silicate cement, Biodentine, Bioaggregate and Intermediate Restorative Material (IRM). The pH and calcium ion concentration of the leachate were investigated. The hydrated cements were characterized using scanning electron microscopy (SEM) and X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). All the cements tested were alkaline. The tricalcium silicate-based cements leached calcium in solution. Scanning electron microscopy of the prototype-radiopacified tricalcium silicate cement, Biodentine and Bioaggregate displayed hydrating cement grains, surrounded by a matrix composed of calcium silicate hydrate and calcium hydroxide. The presence of calcium hydroxide was evident from the XRD plots. FT-IR indicated the occurrence of a poorly crystalline calcium silicate hydrate. Biodentine displayed the presence of calcium carbonate. Bioaggregate incorporated a phosphate-containing phase. IRM consisted of zinc oxide interspersed in an organic matrix. The hydration of prototype-radiopacified tricalcium silicate cement, Biodentine and Bioaggregate resulted in the formation of calcium silicate hydrate and calcium hydroxide, which was leached in solution. The hydrated materials were composed of a cementitous phase that was rich in calcium and silicon and a radiopacifying material. Biodentine included calcium carbonate, and Bioaggregate included silica and calcium phosphate in the powders. IRM was composed of zinc oxide

  8. Synthesis and Characterization of Different Crystalline Calcium Silicate Hydrate: Application for the Removal of Aflatoxin B1 from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Lu Zeng

    2014-01-01

    Full Text Available Different crystalline calcium silicate hydrates (CSH were synthesized under specific hydrothermal conditions and several methods were used to analyze samples. Amorphous calcium silicate hydrates (ACSH mainly consists of disordered calcium silicate hydrate gel (C-S-H gel and crystalline calcium silicate hydrates (CCSH consists of crystallized tobermorite. The adsorption of carcinogenic aflatoxin B1 (AFB1 onto ACSH and CCSH was investigated. The adsorption kinetics was studied using pseudo-first-order and pseudo-second-order kinetic models and intraparticle diffusion model. The pseudo-second-order model provided the best correlation and the intraparticle diffusion controlled the adsorption process of AFB1 onto CCSH. Adsorption isotherm parameters were obtained from Langmuir and Freundlich and the adsorption data fitted to Freundlich much better. Based on the results of N2 adsorption/desorption, adsorption kinetics, and adsorption isotherms, the adsorption mechanism of AFB1 onto CCSH was developed. All results indicate that CCSH has a great potential to be a safe, easy-made, and cost-effective material for the control of AFB1 contamination.

  9. The effect of root dentin conditioning protocols on the push-out bond strength of three calcium silicate sealers

    NARCIS (Netherlands)

    Neelakantan, P.; Nandagopal, M.; Shemesh, H.; Wesselink, P.R.

    2015-01-01

    Objectives: To compare the effects of irrigation protocols on the push-out bond strength of calcium silicate materials at two different time periods (7-days and 3-months). Materials and methods: Root canals (n=300) were irrigated with one of the following (n=60): group 1 (3% NaOCl-17% EDTA); group 2

  10. Success Rates of Pulpotomies in Primary Molars Using Calcium Silicate-Based Materials: A Randomized Control Trial

    National Research Council Canada - National Science Library

    Yeliz Guven; Sermin Dicle Aksakal; Nilufer Avcu; Gulcan Unsal; Elif Bahar Tuna; Oya Aktoren

    2017-01-01

    Objective. The aim of this study was to evaluate and compare, both clinically and radiographically, the effects of calcium silicate-based materials (i.e., ProRoot MTA [PR-MTA], MTA-Plus [MTA-P], and Biodentine [BD...

  11. Impact of Micro Silica Surface Hydroxyl Groups on the Properties of Calcium Silicate Products

    DEFF Research Database (Denmark)

    Haastrup, Sonja; Jørgensen, Bianca; Yu, Donghong

    2017-01-01

    of calcium silicate. We increase the hydroxyl groups by dispersing the micro silica in 10wt% H2O2 (CS10%), and we remove the hydroxyl groups by drying the micro silica at 650°C and then disperse it in water (CS650). A reference sample is also prepared from as-received micro silica dispersed in water (CSref...... for sample CS10% and the crystal phase tobermorite increase compared to CSref. Sample CS650 is mainly composed of Ca(OH)2 after reaction, and hardly any xonotlite and tobermorite crystal phase found. The compressive strength is found to increase for CS10%. The linear shrinkage also increases, which is caused...

  12. Optical properties and Judd–Ofelt analysis of Eu{sup 3+} activated calcium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Barve, R.A., E-mail: rujuta_barve2003@yahoo.com; Suriyamurthy, N.; Panigrahi, B.S.; Venkatraman, B.

    2015-10-15

    Eu{sup 3+} activated calcium silicate was synthesized in stoichiometric ratio using the co-precipitation technique. The phosphors were characterized using X-ray diffraction and photoluminescence technique. Based on Judd–Ofelt (J–O) analysis, the intensity parameters Ω{sub 2} and Ω{sub 4} were calculated from the emission spectra for various Europium concentrations. The determined values indicate higher hypersensitive behavior of the {sup 5}D{sub 0}→{sup 7}F{sub 2} transition of Eu{sup 3+} ions in the host matrix and a stronger covalency. Different radiative properties have been discussed as the function of Eu{sup 3+} concentration. The lifetime decay pattern recorded for these samples indicated single exponential behavior. The quantum efficiency has been calculated to be 62% from the emission spectrum and the fluorescence lifetime was found to be 2.9 ms.

  13. A chemical activity evaluation of two dental calcium silicate-based materials

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2015-06-01

    Full Text Available Calcium silicate-based materials are interesting products widely used in dentistry. The study was designed to compare the chemical reaction between analyzed two preparates and dentin during cavity lining. In our work, dentinal discs were prepared from human extracted teeth filled with Biodentine and MTA+. The samples were then analyzed by way of SEM, EDS and Raman spectroscopy. The obtained results revealed differences in elemental composition between both materials. Biodentine showed higher activity in contact with dentine. Moreover, the interfacial layer in the tooth filled by Biodentine was wider than that in the tooth filled with MTA+. The applied methods of analysis confirmed that both materials have a bioactive potential which is a promising ability.

  14. [Endodontics in motion: new concepts, materials and techniques 1. Hydraulic Calcium Silicate Cements].

    Science.gov (United States)

    Moinzadeh, A T; Jongsma, L; de Groot-Kuin, D; Cristescu, R; Neirynck, N; Camilleri, J

    2015-01-01

    Hydraulic Calcium Silicate Cements (HCSCs) constitute a group of materials that have become increasingly popular in endodontics since the introduction of Mineral Trioxide Aggregate (MTA) in the 1990s. MTA is Portland cement to which bismuth oxide has been added to increase its radiopacity. The most important property of MTA is its capacity to set in water or a humid environment. However, MTA also has important limitations, for example, it's difficult to work with and can discolour teeth. Recently, numerous products based on HCSC chemistry, which can be considered as modifications of MTA intended to reduce its limitations, have become available on the market. Despite their potential advantages, all of these materials have their own specific limitations that are currently insufficiently known and investigated.

  15. Calcium polyphosphate as an additive to zinc-silicate glass ionomer cements.

    Science.gov (United States)

    Valliant, Esther Mae; Gagnier, David; Dickey, Brett Thomas; Boyd, Daniel; Filiaggi, Mark Joseph

    2015-07-01

    Aluminum-free glass ionomer cements (GICs) are under development for orthopedic applications, but are limited by their insufficient handling properties. Here, the addition of calcium polyphosphate (CPP) was investigated as an additive to an experimental zinc-silicate glass ionomer cement. A 50% maximum increase in working time was observed with CPP addition, though this was not clinically significant due to the short working times of the starting zinc-silicate GIC. Surprisingly, CPP also improved the mechanical properties, especially the tensile strength which increased by ∼33% after 30 days in TRIS buffer solution upon CPP addition up to 37.5 wt%. This strengthening may have been due to the formation of ionic crosslinks between the polyphosphate chains and polyacrylic acid. Thus, CPP is a potential additive to future GIC compositions as it has been shown to improve handling and mechanical properties. In addition, CPP may stimulate new bone growth and provide the ability for drug delivery, which are desirable modifications for an orthopedic cement. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  16. Osteogenic and Angiogenic Response to Calcium Silicate-based Endodontic Sealers.

    Science.gov (United States)

    Costa, Fábio; Sousa Gomes, Pedro; Fernandes, Maria Helena

    2016-01-01

    Calcium silicate-based endodontic sealers are reported to favor the regeneration of periradicular tissues, a process requiring concerted osteogenic and angiogenic events. This study compared 4 calcium silicate-based sealers for the effects of their extracts on osteogenic and angiogenic cell behavior. Extracts from ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), MTA Plus (Prevest Denpro Limited, Jammu City, India), MTA Fillapex (Angelus, Londrina, PR, Brazil), and Biodentine (Septodont, Saint-Maur-des-Fosses, France) were prepared from freshly mixed sealers (0.1 g/cm(2)/mL extraction medium) and diluted (1:2-1:20). The sealers were compared for the dose- and time-dependent effects on the proliferation and differentiation of human mesenchymal stem cells (hMSCs) and human umbilical vein endothelial cells (HUVECs). An ex vivo osteogenic assay (regeneration of neonatal mice parietal bone defects) and an in vivo angiogenesis assay (chorioallantoic membrane assay) were performed. Diluted extracts from MTA ProRoot and MTA Plus had evident stimulatory effects on the proliferation of hMSCs, alkaline phosphatase activity, and ex vivo regeneration of bone defects. They also increased HUVEC growth; allowed normal tubularlike network organization; and, in vivo, did not affect angiogenesis. Comparatively, Biodentine also elicited a favorable response on hMSCs and HUVECs, but the overall osteogenic and angiogenic outcome was slightly lower. MTA Fillapex exhibited the highest toxicity in hMSCs and HUVECs and, unlike the other sealers, only allowed a partial regeneration of bone defects. The sealers caused dose- and time-dependent effects on the osteoblastic and endothelial response, eliciting similar cytocompatibility profiles. Results suggest that the induction of both osteogenic and angiogenic events may contribute to the sealers' regenerative outcome. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. In situ hydroxyapatite nanofiber growth on calcium borate silicate ceramics in SBF and its structural characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Yinfu; Huang, Yanlin; Qi, Shuyun [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Chen, Cuili [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2015-10-01

    A novel calcium silicate borate Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramic was firstly prepared by the conventional solid-state reaction. In vitro hydroxyapatite mineralization was investigated by soaking the ceramics in simulated body fluid (SBF) solutions at body temperature (37 °C) for various time periods. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) measurements were applied to investigate the samples before and after the immersion of ceramics in SBF solution. The elemental compositions of a hydroxyapatite layer on the ceramics during the mineralization were confirmed by X-ray energy-dispersive spectra (EDS). Meanwhile, the bending strength and elastic modulus of Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics were also measured, which indicate that the biomaterials based on Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics possess bioactivity and might be a potential candidate as biomaterials for hard tissue repair. The bioactive mineralization ability was evaluated on the base of its crystal structural characteristics, i.e., silanol (Si–OH) and B–OH groups can be easily induced on the surface of Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics soaked in SBF solutions. - Highlights: • Calcium silicate borate Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics were developed as a new biomaterial. • Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} shows a superior in vitro bioactivity by inducing bone-like apatite. • Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} has good mechanical properties as potential candidate biomaterials. • The structure with SiO{sub 4} and BO{sub 3} groups is favorable for hydroxyapatite formation.

  18. Bioactivity and biomineralization ability of calcium silicate-based pulp-capping materials after subcutaneous implantation.

    Science.gov (United States)

    Hinata, G; Yoshiba, K; Han, L; Edanami, N; Yoshiba, N; Okiji, T

    2017-06-26

    To evaluate the abilities of three calcium silicate-based pulp-capping materials (ProRoot MTA, TheraCal LC and a prototype tricalcium silicate cement) to produce apatite-like precipitates after being subcutaneously implanted into rats. Polytetrafluoroethylene tubes containing each material were subcutaneously implanted into the backs of Wistar rats. At 7, 14 and 28 days post-implantation, the implants were removed together with the surrounding connective tissue, and fixed in 2.5% glutaraldehyde in cacodylate buffer. The chemical compositions of the surface precipitates formed on the implants were analysed with scanning electron microscopy-electron probe microanalysis (SEM-EPMA). The distributions of calcium (Ca) and phosphorus (P) at the material-tissue interface were also analysed with SEM-EPMA. Comparisons of the thicknesses of the Ca- and P-rich areas were performed using the Friedman test followed by Scheffe's test at a significant level of 5%. All three materials produced apatite-like surface precipitates containing Ca and P. For each material, elemental mapping detected a region of connective tissue in which the concentrations of Ca and P were higher than those in the surrounding connective tissue. The thickness of this Ca- and P-rich region exhibited the following pattern: ProRoot MTA > prototype tricalcium silicate cement ≥ TheraCal LC. ProRoot MTA had a significantly thicker layer of Ca and P than the other materials at all time-points (P < 0.05), and a significant difference was detected between the prototype cement and TheraCal LC at 28 days (P < 0.05). After being subcutaneously implanted, all of the materials produced Ca- and P-containing surface precipitates and a Ca- and P-rich layer within the surrounding tissue. The thickness of the Ca- and P-rich layer of ProRoot MTA was significantly thicker than that of the other materials. © 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  19. Crystal phase of fibrous calcium phosphates prepared with sodium alginate.

    Science.gov (United States)

    Hayashizaki, J; Ban, S; Arimoto, N; Kato, N; Kimura, Y; Hasegawa, J

    1995-12-01

    This study investigated the effects of preparation conditions on the crystal phase of the fired fiber prepared with sodium alginate. Hydroxyapatite, Ca10(PO4)6(OH)2, hereafter referred to as HA, was only formed in fiber fired at 900 degrees C under proper conditions. There was no significant difference in the crystal phase of the fired fibers prepared using different sodium alginate concentrations and syringe nozzle diameter, although fiber diameters were enlarged with increasing in either. No effects of phosphate type on the crystal phase of the fired fiber were found, but the aging time and the rinsing time had great effects. Sodium calcium phosphate, NaCaPO4, and HA were formed when the aging time was shorter than 5 min. Chlorapatite, Ca5Cl(PO4)3, and HA were formed when the rinsing time was shorter than 3 sec, and HA was formed when the rinsing time was 5 min to 1 hour, beta-TCP, beta-Ca3 (PO4)2, and HA were formed when the rinsing time exceeded 2 weeks.

  20. Physical characteristics, antimicrobial and odontogenesis potentials of calcium silicate cement containing hinokitiol.

    Science.gov (United States)

    Huang, Ming-Hsien; Shen, Yu-Fang; Hsu, Tuan-Ti; Huang, Tsui-Hsien; Shie, Ming-You

    2016-08-01

    Hinokitiol is a natural material and it has antibacterial and anti-inflammatory effects. The purpose of this study was to evaluate the material characterization, cell viability, antibacterial and anti-inflammatory abilities of the hinokitiol-modified calcium silicate (CS) cement as a root end filling material. The setting times, diametral tensile strength (DTS) values and XRD patterns of CS cements with 0-10mM hinokitiol were examined. Then, the antibacterial effect and the expression levels of cyclooxygenase 2 (COX-2) and interleukin-1 (IL-1) of the hinokitiol-modified CS cements were evaluated. Furthermore, the cytocompatibility, the expression levels of the markers of odontoblastic differentiation, mineralized nodule formation and calcium deposition of human dental pulp cells (hDPCs) cultured on hinokitiol-modified CS cements were determined. The hinokitiol-modified CS cements had better antibacterial and anti-inflammatory abilities and cytocompatibility than non-modified CS cements. Otherwise, the hinokitiol-modified CS cements had suitable setting times and better odontoblastic potential of hDPCs. Previous report pointed out that the root-end filling materials may induce inflammatory cytokines reaction. In our study, hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility, antimicrobial properties and active ability of odontoblastic differentiation of hDPCs. Therefore, the hinokitiol-modified CS cement may be a potential root end filling material for clinic. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Nanostructural Deformation Analysis of Calcium Silicate Hydrate in Portland Cement Paste by Atomic Pair Distribution Function

    Directory of Open Access Journals (Sweden)

    Hiroshi Suzuki

    2016-01-01

    Full Text Available The deformation of nanostructure of calcium silicate hydrate (C-S-H in Portland cement (PC paste under compression was characterized by the atomic pair distribution function (PDF, measured using synchrotron X-ray diffraction. The PDF of the PC paste exhibited a unique deformation behavior for a short-range order below 2.0 nm, close to the size of the C-S-H globule, while the deformation for a long-range order was similar to that of a calcium hydroxide phase measured by Bragg peak shift. The compressive deformation of the C-S-H nanostructure was comprised of three stages with different interactions between globules. This behavior would originate from the granular nature of C-S-H, which deforms with increasing packing density by slipping the interfaces between globules, rearranging the overall C-S-H nanostructure. This new approach will lead to increasing applications of the PDF technique to understand the deformation mechanism of C-S-H in PC-based materials.

  2. Effect of temperature and aluminium on calcium (alumino)silicate hydrate chemistry under equilibrium conditions

    Energy Technology Data Exchange (ETDEWEB)

    Myers, Rupert J., E-mail: rjmyers@sheffield.ac.uk [Department of Materials Science and Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom); Laboratory for Concrete and Construction Chemistry, EMPA, Dübendorf 8600 (Switzerland); L' Hôpital, Emilie, E-mail: Emilie.Lhopital@empa.ch [Laboratory for Concrete and Construction Chemistry, EMPA, Dübendorf 8600 (Switzerland); Provis, John L., E-mail: j.provis@sheffield.ac.uk [Department of Materials Science and Engineering, University of Sheffield, S1 3JD Sheffield (United Kingdom); Lothenbach, Barbara, E-mail: Barbara.Lothenbach@empa.ch [Laboratory for Concrete and Construction Chemistry, EMPA, Dübendorf 8600 (Switzerland)

    2015-02-15

    There exists limited information regarding the effect of temperature on the structure and solubility of calcium aluminosilicate hydrate (C–A–S–H). Here, calcium (alumino)silicate hydrate (C–(A–)S–H) is synthesised at Ca/Si = 1, Al/Si ≤ 0.15 and equilibrated at 7–80 °C. These systems increase in phase-purity, long-range order, and degree of polymerisation of C–(A–)S–H chains at higher temperatures; the most highly polymerised, crystalline and cross-linked C–(A–)S–H product is formed at Al/Si = 0.1 and 80 °C. Solubility products for C–(A–)S–H were calculated via determination of the solid-phase compositions and measurements of the concentrations of dissolved species in contact with the solid products, and show that the solubilities of C–(A–)S–H change slightly, within the experimental uncertainty, as a function of Al/Si ratio and temperature between 7 °C and 80 °C. These results are important in the development of thermodynamic models for C–(A–)S–H to enable accurate thermodynamic modelling of cement-based materials.

  3. In Vitro Cytotoxicity of Calcium Silicate-Based Endodontic Cement as Root-End Filling Materials

    Directory of Open Access Journals (Sweden)

    Selen Küçükkaya

    2016-01-01

    Full Text Available The aim of this study was to evaluate the cytotoxicity of three types of calcium silicate-based endodontic cement after different incubation periods with human periodontal ligament fibroblasts. Human periodontal ligament fibroblasts were cultured from extracted third molars and seeded in 96-well plates. MTA, calcium enriched mixture (CEM cement, and Biodentine were prepared and added to culture insert plates which were immediately placed into 96-well plates containing cultured cells. After incubation periods of 24, 48, and 72 hours, cell viability was determined with WST-1 assay. Data were analysed statistically by ANOVA with repeated measures and Bonferroni tests. There was no significant difference in cell viability amongst the test materials after each incubation period (P>0.05. MTA and CEM presented more than 90% cell viability after 24 and 48 hours of incubation and showed statistically significant decrease in cell viability after 72 hours of incubation (P<0.05. Biodentine showed significantly less cell viability (73% after 24 hours of incubation, whereas more than 90% cell viability was seen after 48 and 72 hours of incubation (P<0.05. Despite the significant changes in cell viability over time, materials presented similar cytotoxicity profile. Biodentine and CEM can be considered as alternative materials for root-end surgery procedures.

  4. Apatite formation on bioactive calcium-silicate cements for dentistry affects surface topography and human marrow stromal cells proliferation.

    Science.gov (United States)

    Gandolfi, Maria Giovanna; Ciapetti, Gabriela; Taddei, Paola; Perut, Francesca; Tinti, Anna; Cardoso, Marcio Vivan; Van Meerbeek, Bart; Prati, Carlo

    2010-10-01

    The effect of ageing in phosphate-containing solution of bioactive calcium-silicate cements on the chemistry, morphology and topography of the surface, as well as on in vitro human marrow stromal cells viability and proliferation was investigated. A calcium-silicate cement (wTC) mainly based on dicalcium-silicate and tricalcium-silicate was prepared. Alpha-TCP was added to wTC to obtain wTC-TCP. Bismuth oxide was inserted in wTC to prepare a radiopaque cement (wTC-Bi). A commercial calcium-silicate cement (ProRoot MTA) was tested as control. Cement disks were aged in DPBS for 5 h ('fresh samples'), 14 and 28 days, and analyzed by ESEM/EDX, SEM/EDX, ATR-FTIR, micro-Raman techniques and scanning white-light interferometry. Proliferation, LDH release, ALP activity and collagen production of human marrow stromal cells (MSC) seeded for 1-28 days on the cements were evaluated. Fresh samples exposed a surface mainly composed of calcium-silicate hydrates CSH (from the hydration of belite and alite), calcium hydroxide, calcium carbonate, and ettringite. Apatite nano-spherulites rapidly precipitated on cement surfaces within 5 h. On wTC-TCP the Ca-P deposits appeared thicker than on the other cements. Aged cements showed an irregular porous calcium-phosphate (Ca-P) coating, formed by aggregated apatite spherulites with interspersed calcite crystals. All the experimental cements exerted no acute toxicity in the cell assay system and allowed cell growth. Using biochemical results, the scores were: fresh cements>aged cements for cell proliferation and ALP activity (except for wTC-Bi), whereas fresh cementsbismuth on cell proliferation was reduced by the progressive increase of the biocoating thickness on aged cement. In conclusion, the experimental cements have adequate biological properties to be used as root-end/root repair filling materials or pulp capping materials. The alfa-TCP doped cement represents a new potential bioactive material for expanded applications in

  5. Lime and calcium-magnesium silicate in the ionic speciation of an Oxisol

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    João Arthur Antonangelo

    Full Text Available ABSTRACT Plant residues and certain fertilizers accelerate soil acidification and increase the levels of aluminum-Al+3 in soils under no-tillage (NT. Silicates act as acidity amendments and as a source of silicon as in H4SiO4. An increase in the pH of soil solution causes the deprotonation of H4SiO4 and generates the anionic form (H3SiO4−. The aim of this study was to evaluate the ionic speciation of Si, Al, Ca, Mg and K in aqueous extracts by means of a software calculation. Since 2006, a field experiment has been under way on an Oxisol under NT subjected to lime and calcium-magnesium silicate applications under four crop systems. The amendments were applied in Oct 2006 and in Oct 2011, aiming to raise base saturation to 70 %. Soil samples were collected in Oct 2013, at depths of 0-5, 5-10, 10-20, 20-40 and 40-60 cm. Both Ca and Mg formed complexes with dissolved organic carbon (DOC whereas the same was not observed for potassium. These three basic cations were mostly in their free forms regardless of treatment, while Al was mostly complexed with DOC even at the lowest depths (40-60 cm. The highest value of free Al form was 15 %. Si was almost 100 % as H4SiO4, and its activity was similar to its concentration in solution for all crop systems and at all depths, regardless of amendment applied. The percentages of H3SiO4− and Al-H3SiO42+ were irrelevant, providing more phytoavailable H4SiO4 in soil solution.

  6. A multinuclear solid state NMR spectroscopic study of the structural evolution of disordered calcium silicate sol-gel biomaterials.

    Science.gov (United States)

    Lin, Zhongjie; Jones, Julian R; Hanna, John V; Smith, Mark E

    2015-01-28

    Disordered sol-gel prepared calcium silicate biomaterials show significant, composition dependent ability to bond with bone. Bone bonding is attributed to rapid hydroxycarbonate apatite (HCA) formation on the glass surface after immersion in body fluid (or implantation). Atomic scale details of the development of the structure of (CaO)x(SiO2)1-x (x = 0.2, 0.3 and 0.5) under heat treatment and subsequent dissolution in simulated body fluid (SBF) are revealed through a multinuclear solid state NMR approach using one-dimensional (17)O, (29)Si, (31)P and (1)H. Central to this study is the combination of conventional static and magic angle spinning (MAS) and two-dimensional (2D) triple quantum (3Q) (17)O NMR experiments that can readily distinguish and quantify the bridging (BOs) and non-bridging (NBOs) oxygens in the silicate network. Although soluble calcium is present in the sol, the (17)O NMR results reveal that the sol-gel produced network structure is initially dominated by BOs after gelation, aging and drying (e.g. at 120 °C), indicating a nanoscale mixture of the calcium salt and a predominantly silicate network. Only once the calcium salt is decomposed at elevated temperatures do the Ca(2+) ions become available to break BO. Apatite forming ability in SBF depends strongly on the surface OH and calcium content. The presence of calcium aids HCA formation via promotion of surface hydration and the ready availability of Ca(2+) ions. (17)O NMR shows the rapid loss of NBOs charge balanced by calcium as it is leached into the SBF. The formation of nanocrystalline, partially ordered HCA can be detected via(31)P NMR. This data indicates the importance of achieving the right balance of BO/NBO for optimal biochemical response and network properties.

  7. Late sodium current in the pathophysiology of cardiovascular disease: consequences of sodium–calcium overload

    OpenAIRE

    Noble, D; Noble, P J

    2006-01-01

    Late sodium current in cardiac cells is very small compared with the fast component, but as it flows throughout the action potential it may make a substantial contribution to sodium loading during each cardiac cycle. Late sodium current may contribute to triggering arrhythmia in two ways: by causing repolarisation failure (early afterdepolarisations); and by triggering late afterdepolarisations attributable to calcium oscillations in sodium–calcium overload conditions. Reduction of late sodiu...

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

    Science.gov (United States)

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

    1979-05-01

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

  9. Crystal Field Parameters and Optical Parameters of Nd3+ in Sodium Bismuth Silicate Glass

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    Vinoy Thomas

    2015-06-01

    Full Text Available Neodymium doped sodium bismuth silicate glasses were prepared by the melt quench technique. Optical absorption spectra of the Nd3+ion in the present glassy systems were recorded in the UV-Vis-NIR region. Taylor series expansion method was adopted for theoretical evaluation of various crystal field parameters such as the Slater-Condon (F2,F4,F6, spin orbit and Racah parameters (E1,E2,E3. Oscillator strength and electric dipole line strength of the observed transitions were evaluated with the help of Judd-Ofelt (JO theory. Radiative transition probability (A, total radiative transition probability (At, radiative life time (trad, branching ratios (b and integrated absorption (sa cross section for stimulated emission between the meta stable state 4F3/2 and 4IJ ( J= 15/2,13/2,11/2 and 9/2 levels were calculated using JO parameters. Optical basicity of the glass was found to increase with the addition of  bismuth.

  10. Formation of magnesium silicate hydrate (M-S-H) cement pastes using sodium hexametaphosphate

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tingting [Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024 (China); Department of Materials, Centre for Advanced Structural Ceramics, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Vandeperre, Luc J. [Department of Materials, Centre for Advanced Structural Ceramics, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Cheeseman, Christopher R., E-mail: c.cheeseman@imperial.ac.uk [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2014-11-15

    Magnesium silicate hydrate (M-S-H) gel is formed by the reaction of brucite with amorphous silica during sulphate attack in concrete and M-S-H is therefore regarded as having limited cementing properties. The aim of this work was to form M-S-H pastes, characterise the hydration reactions and assess the resulting properties. It is shown that M-S-H pastes can be prepared by reacting magnesium oxide (MgO) and silica fume (SF) at low water to solid ratio using sodium hexametaphosphate (NaHMP) as a dispersant. Characterisation of the hydration reactions by x-ray diffraction and thermogravimetric analysis shows that brucite and M-S-H gel are formed and that for samples containing 60 wt.% SF and 40 wt.% MgO all of the brucites react with SF to form M-S-H gel. These M-S-H cement pastes were found to have compressive strengths in excess of 70 MPa.

  11. Mechanical properties of polymer-infiltrated-ceramic (sodium aluminum silicate) composites for dental restoration.

    Science.gov (United States)

    Cui, Bencang; Li, Jing; Wang, Huining; Lin, Yuanhua; Shen, Yang; Li, Ming; Deng, Xuliang; Nan, Cewen

    2017-07-01

    To fabricate indirect restorative composites for CAD/CAM applications and evaluate the mechanical properties. Polymer-infiltrated-ceramic composites were prepared through infiltrating polymer into partially sintered sodium aluminum silicate ceramic blocks and curing. The corresponding samples were fabricated according to standard ISO-4049 using for mechanical properties measurement. The flexural strength and fracture toughness were measured using a mechanical property testing machine. The Vickers hardness and elastic modulus were calculated from the results of nano-indentation. The microstructures were investigated using secondary electron detector. The density of the porous ceramic blocks was obtained through TG-DTA. The conversion degrees were calculated from the results of mid-infrared spectroscopy. The obtained polymer infiltrated composites have a maximum flexural strength value of 214±6.5MPa, Vickers hardness of 1.76-2.30GPa, elastic modulus of 22.63-27.31GPa, fracture toughness of 1.76-2.35MPam 1/2 and brittleness index of 0.75-1.32μm -1/2 . These results were compared with those of commercial CAD/CAM blocks. Our results suggest that these materials with good mechanical properties are comparable to two commercial CAD/CAM blocks. The sintering temperature could dramatically influence the mechanical properties. Restorative composites with superior mechanical properties were produced. These materials mimic the properties of natural dentin and could be a promising candidate for CAD/CAM applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. A comparison of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning.

    Science.gov (United States)

    Bradberry, Sally; Vale, Allister

    2009-11-01

    This article reviews the experimental and clinical studies that have compared the efficacy (impact on urine lead excretion, blood and tissue lead concentrations, resolution of features and survival) of sodium calcium edetate (edetate calcium disodium) and succimer (DMSA) in the treatment of inorganic lead poisoning. It also summarizes the pharmacokinetic and pharmacodynamic aspects and the adverse effects of treatment. Medline, Toxline, and Embase were searched for all available years to June 2009. PHARMACOKINETICS AND PHARMACODYNAMICS: The absorption of oral DMSA is more complete than sodium calcium edetate; the latter has to be administered parenterally. Both antidotes are distributed predominantly extracellularly. Sodium calcium edetate is not metabolized, whereas DMSA is extensively metabolized to mixed disulfides of cysteine. The two antidotes have elimination half-lives of less than 60 min. There is no evidence that either antidote crosses the blood-brain barrier to any major extent. Sodium calcium edetate chelates lead by displacement of the central Ca2+ ion with Pb2+. The nature of the DMSA-lead chelate is less clearly defined. There is evidence that the mixed disulfides of cysteine are the active chelating moiety in humans. If this is the case, this suggests that chelation occurs principally, if not exclusively, in the kidney. The primary source of lead mobilized by sodium calcium edetate is bone with an additional contribution from kidney and liver. Comparison of the experimental studies is complicated by substantial variations in study design, particularly the antidote dose, the route and duration of treatment, the amount and duration of lead dosing, and lack of direct comparison between antidotes (comparison was usually made with control). In experimental studies that used equimolar and clinically relevant antidote doses and assessed the impact of DMSA and sodium calcium edetate on urine lead excretion and/or blood lead concentrations, similar results

  13. Photo-luminescent properties of a green or red emitting Tb3+ or Eu3+ doped calcium magnesium silicate phosphors

    Science.gov (United States)

    Onani, Martin O.; Dejene, Francis B.

    2014-04-01

    This study describes green-emitting Tb3+ or red-emitting Eu3+ doped calcium magnesium silicate phosphors by ultraviolet excitation at 335 nm. The rare earth activated amorphous calcium silicate was prepared by a solution-combustion process at 600 °C for 5-10 min. The Ca2MgSi2O7 prepared using urea and ammonium nitrate has a tetragonal crystal structure. The resulting Tb3+-doped phosphor emitted green light centered at 544 nm. The optimum excitation wavelength within the range 300-400 nm was 335 nm. The intensity and emitting wavelength of the Eu3+ doped samples can be controlled by annealing in a reducing or oxidizing environment, allowing light to be emitted as green or red. When the reducing environment is optimized, the emission spectrum of Ca2MgSi2O7:Eu2+ is a broad band at 497 nm.

  14. Calcium Silicate Improved Bioactivity and Mechanical Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate Scaffolds

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    Cijun Shuai

    2017-05-01

    Full Text Available The poor bioactivity and mechanical properties have restricted its biomedical application, although poly(3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV had good biocompatibility and biodegradability. In this study, calcium silicate (CS was incorporated into PHBV for improving its bioactivity and mechanical properties, and the porous PHBV/CS composite scaffolds were fabricated via selective laser sintering (SLS. Simulated body fluid (SBF immersion tests indicated the composite scaffolds had good apatite-forming ability, which could be mainly attributed to the electrostatic attraction of negatively charged silanol groups derived from CS degradation to positively charged calcium ions in SBF. Moreover, the compressive properties of the composite scaffolds increased at first, and then decreased with increasing the CS content, which was ascribed to the fact that CS of a proper content could homogeneously disperse in PHBV matrix, while excessive CS would form continuous phase. The compressive strength and modulus of composite scaffolds with optimal CS content of 10 wt % were 3.55 MPa and 36.54 MPa, respectively, which were increased by 41.43% and 28.61%, respectively, as compared with PHBV scaffolds. Additionally, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay indicated MG63 cells had a higher proliferation rate on PHBV/CS composite scaffolds than that on PHBV. Alkaline phosphatase (ALP staining assay demonstrated the incorporation of CS significantly promoted osteogenic differentiation of MG63 cells on the scaffolds. These results suggest that the PHBV/CS composite scaffolds have the potential in serving as a substitute in bone tissue engineering.

  15. Physical characteristics, antimicrobial and odontogenesis potentials of calcium silicate cement containing hinokitiol

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Ming-Hsien [Institute of Oral Science, Chung Shan Medical University, Taichung City, Taiwan (China); Shen, Yu-Fang; Hsu, Tuan-Ti [3D Printing Medical Research Center, China Medical University Hospital, China Medical University, Taichung City, Taiwan (China); Huang, Tsui-Hsien [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Department of Stomatology, Chung Shan Medical University Hospital, Taichung City, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [3D Printing Medical Research Center, China Medical University Hospital, China Medical University, Taichung City, Taiwan (China)

    2016-08-01

    Hinokitiol is a natural material and it has antibacterial and anti-inflammatory effects. The purpose of this study was to evaluate the material characterization, cell viability, antibacterial and anti-inflammatory abilities of the hinokitiol-modified calcium silicate (CS) cement as a root end filling material. The setting times, diametral tensile strength (DTS) values and XRD patterns of CS cements with 0–10 mM hinokitiol were examined. Then, the antibacterial effect and the expression levels of cyclooxygenase 2 (COX-2) and interleukin-1 (IL-1) of the hinokitiol-modified CS cements were evaluated. Furthermore, the cytocompatibility, the expression levels of the markers of odontoblastic differentiation, mineralized nodule formation and calcium deposition of human dental pulp cells (hDPCs) cultured on hinokitiol-modified CS cements were determined. The hinokitiol-modified CS cements had better antibacterial and anti-inflammatory abilities and cytocompatibility than non-modified CS cements. Otherwise, the hinokitiol-modified CS cements had suitable setting times and better odontoblastic potential of hDPCs. Previous report pointed out that the root-end filling materials may induce inflammatory cytokines reaction. In our study, hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility, antimicrobial properties and active ability of odontoblastic differentiation of hDPCs. Therefore, the hinokitiol-modified CS cement may be a potential root end filling material for clinic. - Highlights: • The hinokitiol-modified CS up-regulation of odontogenic of hDPCs. • Promoted proliferation of hDPCs on hinokitiol-modified CS. • The hinokitiol-modified CS cements not only inhibited the expression level of inflammatory cytokines, but also had better cytocompatibility. • The hinokitiol-modified CS up-regulation of odontogenic of hPDLs.

  16. Osteoblast-like cell responses to ion products released from magnesium- and silicate-containing calcium carbonates.

    Science.gov (United States)

    Yamada, Shinya; Ota, Yoshio; Obata, Akiko; Kasuga, Toshihiro

    2017-01-01

    Inorganic ions released from bioceramics and bioactive glasses have been reported to influence osteogenic cell functions. Cell responses depend on types of the ions provided, for example, silicate ion has been found to up-regulate their proliferation, differentiation and mineralization. Mouse osteoblast-like cells (MC3T3-E1) were cultured in media containing silicate and calcium ions with/without magnesium ion to evaluate their combined effects on the cell's functions. The cells were cultured in the media containing the extract of silicate-containing vaterite (SiV) and magnesium- and siloxane-containing one (MgSiV) and normal medium and then their adhesion, proliferation, differentiation and mineralization were evaluated. The adhesion of the cells was enhanced when they were cultured in the medium containing MgSiV-extract. Their proliferation and differentiation were up-regulated in both media containing MgSiV-extract and SiV-extract. In particular, the MgSiV-extract significantly enhanced their differentiation than the SiV-extract. This was supported by the mineralization test's results, which showed a large amount of mineral deposit was observed in the cells cultured in the MgSiV-extract medium. Providing the three kinds of ions was effective for up-regulating the cell's mineralization compared to providing silicate and calcium ions without magnesium ion.

  17. Fluorescence Properties and Synthesis of Green-Emitting Tb3+-Activated Amorphous Calcium Silicate Phosphor by Ultraviolet Irradiation of 378 nm

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Kojima

    2012-01-01

    Full Text Available The excitation wavelength of conventional Tb3+-activated phosphor is near 270 nm. This study describes novel green-emitting Tb3+-activated amorphous calcium silicate by ultraviolet excitation at 378 nm. The Tb3+-activated amorphous calcium silicate was prepared by heating a sample of Tb3+-activated calcium silicate hydrate (CSH at 900°C for 30 minutes. The emission wavelength of the resulting phosphor was 544 nm. The optimum excitation wavelength within the range 300–400 nm was 378 nm. The Tb3+-activated amorphous calcium silicate emitted green by ultraviolet irradiation. The optimum initial Tb/Ca atomic ratio of this phosphor was about 0.5. A mechanism for the action of the phosphor is proposed, in which Tb3+ ions existing in the layer of the CSH lead to loss of water molecules and OH groups.

  18. Effect of calcium and magnesium silicate on the growth of the castor oil plant subjected to salinity levels

    OpenAIRE

    de Brito Neto, Jose Felix [UNESP; Macedo Beltrao, Napoleao de Esberard; Gonsiorkiewicz Rigon, Joao Paulo [UNESP; Capuani, Silvia [UNESP

    2012-01-01

    Salt stress decreases the osmotic potential of soil solution causing water stress, causing toxic effects in the plants resulting in injuries on the metabolism and nutritional disorders, thus compromising the plant growth, resulting in lower production. The calcium silicate and magnesium can perform the same function as limestone, besides providing silicon to plants, may also contribute to the resistance of plants to salt stress. Thus, the objective of this study was to evaluate the effect of ...

  19. Biocompatibility of three new calcium silicate-based endodontic sealers on human periodontal ligament stem cells.

    Science.gov (United States)

    Collado-González, M; García-Bernal, D; Oñate-Sánchez, R E; Ortolani-Seltenerich, P S; Lozano, A; Forner, L; Llena, C; Rodríguez-Lozano, F J

    2017-09-01

    To evaluate the biocompatibility of three calcium silicate-based endodontic sealers, Bioroot BC Sealer (Septodont, Saint-Maur-des-Fosses, France), Endoseal MTA (EndoSeal, Maruchi, Seoul, Korea) and Nano-ceramic Sealer (B&L Biotech, Fairfax, VA, USA) (NCS), on human periodontal ligament stem cells (hPDLSCs). Human periodontal ligament stem cells were cultured in the presence of various endodontic sealer eluates for 24 h. Cell viability was determined using the MTT assay. Cell death and changes in phenotype induced by the set endodontic sealer eluates were evaluated through flow cytometry. Also, an in vitro scratch wound-healing model was used to determine their effects in cell migration. Finally, to assess cell morphology and attachment to the different sealers, hPDLSCs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). One-way analysis of variance (anova) followed by a Bonferroni post-test was performed (P endodontic sealers for clinical application. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  20. Carboxymethyl fenugreek galactomannan-gellan gum-calcium silicate composite beads for glimepiride delivery.

    Science.gov (United States)

    Bera, Hriday; Mothe, Srilatha; Maiti, Sabyasachi; Vanga, Sridhar

    2017-09-13

    Novel carboxymethyl fenugreek galactomannan (CFG)-gellan gum (GG)-calcium silicate (CS) composite beads were developed for controlled glimepiride (GLI) delivery. CFG having degree of carboxymethylation of 0.71 was synthesized and characterized by FTIR, DSC and XRD analyses. Subsequently, GLI-loaded hybrids were accomplished by ionotropic gelation technique employing Ca+2/Zn+2/Al+3 ions as cross-linkers. All the formulations demonstrated excellent drug encapsulation efficiency (DEE, 48-97%) and sustained drug release behaviour (Q8h, 62-94%). These quality attributes were remarkably influenced by polymer-blend (GG:CFG) ratios, cross-linker types and CS inclusion. The drug release profile of the optimized formulation (F-6) was best fitted in zero-order model with anomalous diffusion driven mechanism. It also conferred excellent ex vivo mucoadhesive property and considerable hypoglycemic effect in streptozotocin-induced diabetic rats. Furthermore, the beads were characterized for drug-excipients compatibility, drug crystallinity, thermal behaviour and surface morphology. Thus, the developed hybrid matrices are appropriate for controlled delivery of GLI for Type 2 diabetes management. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Graphene Nanosheets to Improve Physico-Mechanical Properties of Bioactive Calcium Silicate Cements

    Directory of Open Access Journals (Sweden)

    Nileshkumar Dubey

    2017-05-01

    Full Text Available Bioactive calcium silicate cements are widely used to induce mineralization, to cement prosthetic parts, in the management of tooth perforations, and other areas. Nonetheless, they can present clinical disadvantages, such as long setting time and modest physico-mechanical properties. The objective of this work was to evaluate the potential of graphene nanosheets (GNS to improve two bioactive cements. GNS were obtained via reduction of graphite oxide. GNS were mixed (1, 3, 5, and 7 wt % with Biodentine (BIO and Endocem Zr (ECZ, and the effects on setting time, hardness, push-out strength, pH profile, cell proliferation, and mineralization were evaluated. Statistics were performed with two-way ANOVA and Tukey test (α = 0.05. GNS has not interfered in the composition of the set cements as confirmed by Raman, FT-IR and XRD. GNS (1 and 3 wt % shortened the setting time, increased hardness of both materials but decreased significantly the push-out strength of ECZ. pH was not affected but 1 wt % and 7 wt % to ECZ and 5 wt % to BIO increased the mineralization compared to the controls. In summary, GNS may be an alternative to improve the physico-mechanical properties and bioactivity of cements. Nonetheless, the use of GNS may not be advised for all materials when effective bonding is a concern.

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

    Science.gov (United States)

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

    2012-07-01

    Nanotechnology creates new possibilities to control and improve material properties for civil infrastructure. Special focus in this area is put on Portland cement and gypsum. Together their annual production is by far larger than for any other material worldwide. Nanomodification of these materials can be done during the few hours between dissolution and hardening, especially by nucleation of the re-crystallization with suitable colloids. Here we report first results in homogeneous seeding of the precipitation of calcium silicate hydrates within a real Portland cement composition. The occupational safety during the production phase and during mixing of concrete paste is addressed in detail by in vivo testing. We perform 5-day inhalation with 21-day recovery in rats and analyze organ-specific toxicity and 71 endpoints from bronchoalveolar lavage (BALF) and blood. In BALF parameters, no test-related changes were observed, indicating the generally low toxicity of the test material. Some mild lesions were observed in larynx level. In the lungs, all animals of the 50 mg/m³ concentration group revealed a minimal to mild increase in alveolar macrophages, which recovered back to control level.

  3. The Performance of Calcium Silicate Board Partition Fireproof Drywall Assembly with Junction Box under Fire

    Directory of Open Access Journals (Sweden)

    Yinuo Wang

    2015-01-01

    Full Text Available This study uses a metal stud partition fireproof drywall measuring 83 mm in thickness as a test specimen to explore the impact of an embedded junction box on the firefighting performance of the wall through one time of standard fire test on a 300 cm × 300 cm area and five times of standard fire test on a 120 cm × 120 cm area. The results show that the quality of calcium silicate board plays a big role in the fireproof effectiveness. The embedded junction box located on the backside of the fire can reduce the effectiveness of the wall, especially the area above the socket. The thickness of rock wool may increase the performance, but in a limited rate. External junction box may not impact the fireproofing performance of the wall but it still possesses some safety risks. An embedded junction box measuring 101 × 55 mm could already damage the fire compartment, and in reality there may be more complicated situations that should be noted and improved.

  4. Effects of glass fiber modified with calcium silicate hydrate (C-S-H(I)) reinforced cement

    Science.gov (United States)

    Xin, M.; Zhang, L.; Ge, S.; Cheng, X.

    2017-03-01

    In this paper, calcium silicate hydrate (C-S-H(I)) and glass fiber modified with C-S-H(I) (SiF) at ambient temperature were synthesized. SiF and untreated fiber (OF) were incorporated into cement paste. Phase composition of C-S-H(I), SiF and OF was characterized by XRD. The surface morphologies were characterized by SEM. Flexural performance of fiber reinforced cement (FRC) at different curing ages was investigated. Results indicated that both SiF and OF could reinforce cement paste. SiF had a more positive effect on improving the flexural performance of FRC than OF. The strength of SiF reinforced cement was 11.48MPa after 28 days curing when fiber volume was 1.0%, 12.55% higher than that of OF reinforced cement. The flexural strength increased with the addition of fiber volume. However, the large dosage of fiber might cause a decrease in flexural strength of FRC.

  5. Combination of simvastatin, calcium silicate/gypsum, and gelatin and bone regeneration in rabbit calvarial defects

    Science.gov (United States)

    Zhang, Jing; Wang, Huiming; Shi, Jue; Wang, Ying; Lai, Kaichen; Yang, Xianyan; Chen, Xiaoyi; Yang, Guoli

    2016-03-01

    The present study was performed to determine whether simvastatin improves bone regeneration when combined with calcium silicate/gypsum and gelatin (CS-GEL). The surface morphology was determined using field-emission scanning electron microscopy (FSEM). Degradation in vitro was evaluated by monitoring the weight change of the composites soaked in phosphate buffered saline (PBS). Drug release was evaluated using high-performance liquid chromatography (HPLC). Cytotoxicity testing was performed to assess the biocompatibility of composites. Four 5 mm-diameter bone defects were created in rabbit calvaria. Three sites were filled with CS-GEL, 0.5 mg simvastatin-loaded CS-GEL (SIM-0.5) and 1.0 mg simvastatin-loaded CS-GEL (SIM-1.0), respectively, and the fourth was left empty as the control group. Micro-computed tomography (micro-CT) and histological analysis were carried out at 4 and 12 weeks postoperatively. The composites all exhibited three-dimensional structures and showed the residue with nearly 80% after 4 weeks of immersion. Drug release was explosive on the first day and then the release rate remained stable. The composites did not induce any cytotoxicity. The results in vivo demonstrated that the new bone formation and the expressions of BMP-2, OC and type I collagen were improved in the simvastatin-loaded CS-GEL group. It was concluded that the simvastatin-loaded CS-GEL may improve bone regeneration.

  6. Sorption of As(V) from waters using chitosan and chitosan-immobilized sodium silicate prior to atomic spectrometric determination.

    Science.gov (United States)

    Boyaci, Ezel; Eroğlu, Ahmet E; Shahwan, Talal

    2010-01-15

    A natural biosorbent containing amine functional groups, chitosan, and a novel sorbent, chitosan-immobilized sodium silicate, were prepared and utilized for the selective sorption of As(V) from waters prior to its determination by atomic spectrometric techniques, namely, hydride generation atomic absorption spectrometry (HGAAS) and inductively coupled plasma mass spectrometry (ICP-MS). Chitosan was synthesized from chitin and sodium silicate was used as the immobilization matrix due to its straightforward synthesis. Through sequential sorption studies, it was shown that chitosan-immobilized sodium silicate has exhibited a better chemical stability than the chitosan itself which demonstrates the advantage of immobilization method. Both chitosan and chitosan-immobilized sodium silicate were shown to selectively adsorb As(V), arsenate, from waters at pH 3.0 at which neither chitin nor sodium silicate displayed any sorption towards As(V). The sorption of arsenate by chitosan is supposed to have electrostatic nature since pH of 3.0 is both the point at which the amino groups in chitosan are protonated and also the predominant form of As(V) is H(2)AsO(4)(-). A pre-oxidation step is required if both As(III) and As(V) are to be determined. Desorption from the sorbents was realized with 1.0% (w/v) l-cysteine prepared in a pH 3.0 solution adjusted with HCl. Among the possible interfering species tested, only Te(IV) and Sb(III) were shown to cause a decrease in the sorption capacity especially at high interferant concentrations. High concentrations of Sb(III) also resulted in gas phase interference during hydride generation. The validity of the method was checked both via spike recovery experiments and also through the analysis of a standard reference material. Spike recovery tests were carried out with four different types of water; namely, ultra-pure, bottled drinking, tap, and sea water; and percent recovery values were found to be 114 (+/-4), 112 (+/-2), 43 (+/-4), and 0

  7. Preliminary study of raw material for calcium silicate/PVA coating on Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Farah ' Atiqah bt Abdul; Shamsudin, Roslinda, E-mail: linda@ukm.edu.my [School of Applied Physics, Faculty of Science and Technology Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2015-09-25

    Calcium silicate bioceramic was prepared from the rice husk and limestone resources using the sol gel method. The preparations of CaSiO{sub 3} formulation were differ from the previous study due CaO/SiO{sub 2} amount with 45:55 ratio. X-Ray Fluorescence analysis was carried out to clarify the amount of SiO{sub 2} and CaO content in the limestone and rice husk ash. The high amount of CaO was found in the limestone with the percentages of 97.22%, whereby 89% of SiO{sub 2} content of the rice husk ash. Several milling time were studied to obtain the optimized milling ti me and speed in progress to obtain nano size particle. The particle size analysis result confirms that increase in milling time does not certainly reduce the size of particle. The addition of 0.05% polyvinyl alcohol as a binder did not change the phases or composition of calcium silicates after examined by X-Ray diffraction analysis which make it suitable to be used as a binder for calcium silicate coating without changing the chemical structure.

  8. Quantitative Evaluation by Glucose Diffusion of Microleakage in Aged Calcium Silicate-Based Open-Sandwich Restorations

    Directory of Open Access Journals (Sweden)

    S. Koubi

    2012-01-01

    Full Text Available This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups (=10 to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxhaven, Germany in open-sandwich restorations covered with a light-cured composite. Positive (=5 and negative (=5 controls were included. The teeth simultaneously underwent thermocycling and mechanocycling using a fatigue cycling machine (1,440 cycles, 5–55°C; 86,400 cycles, 50 N/cm2. The specimens were then stored in phosphate-buffered saline to simulate aging. After 1 year, the teeth were submitted to glucose diffusion, and the resulting data were analyzed with a nonparametric Mann-Whitney test. The Biodentine group and the Ionolux group presented glucose concentrations of 0.074 ± 0.035 g/L and 0.080 ± 0.032 g/L, respectively. No statistically significant differences were detected between the two groups. Therefore, the calcium silicate-based material performs as well as the resin-modified glass ionomer cement in open-sandwich restorations.

  9. Application of soil block without burning process and calcium silicate panels as building wall in mountainous area

    Science.gov (United States)

    Noerwasito, Vincentius Totok; Nasution, Tanti Satriana Rosary

    2017-11-01

    Utilization of local building materials in a residential location in mountainous area is very important, considering local material as a low-energy building material because of low transport energy. The local building materials used in this study are walls made from soil blocks. The material was made by the surrounding community from compacted soil without burning process. To maximize the potential of soil block to the outdoor temperature in the mountains, it is necessary to add non-local building materials as an insulator from the influence of the outside air. The insulator was calcium silicate panel. The location of the research is Trawas sub-district, Mojokerto regency, which is a mountainous area. The research problem is on applying the composition of local materials and calcium silicate panels that it will be able to meet the requirements as a wall building material and finding to what extent the impact of the wall against indoor temperature. The result from this research was the application of soil block walls insulated by calcium silicate panels in a building model. Besides, because of the utilization of those materials, the building has a specific difference between indoor and outdoor temperature. Thus, this model can be applied in mountainous areas in Indonesia.

  10. Sol-gel synthesis and characterizations of hybrid chitosan-PEG/calcium silicate nanocomposite modified with ZnO-NPs and (E102) for optical and antibacterial applications.

    Science.gov (United States)

    Youssef, Ahmed M; El-Nahrawy, Amany M; Abou Hammad, Ali B

    2017-04-01

    Hybrid Chitosan/Poly ethylene glycol/calcium silicate (CS/PEG/calcium silicate) nanocomposite modified with different two types, zinc oxide nanoparticles (ZnO-NPs) and tartrazine dye (E102) were prepared by sol gel method and the characterization of their structure and biological properties were carried out in order to evaluate the possible use in optical and biomedical fields. The hybrid CS/PEG/calcium silicate complex formations have been established by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopic analysis. The spheres-like chitosan-PEG/calcium silicate and modified with both ZnO-NPs and (E102) were obtained with optimum concentration of 11% ZnO-NPs and 0.3gm (E102) dyes. Spheres-like particle shape of these nanocomposites from SEM images, higher UV absorption in the region of 200-300nm by UV-vis absorption spectrophotometer are recorded. The fabricate CS/PEG/calcium silicate nanocomposites and doped with ZnO-NPs and tetrazine were studied contrary to gram positive (Staphylococcus aureus), gram negative (Pseudomonas aeruginosa) bacteria, fungi (Candidia albicans) and Aspargillus niger via the agar plate method. The obtained results indicated that the prepared CS-PEG/calcium silicate nanocomposites have good antibacterial properties agnist G(+ve), G(-ve) bacteria and fungi, so that it could be a promised candidate in various optical and in biological applications as well as packaging application. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Steam based conversion coating on AA6060 alloy: Effect of sodium silicate chemistry and corrosion performance

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Bordo, Kirill; Tabrizian, Naja

    2017-01-01

    Surface treatment of aluminium alloy AA6060 using an industrially applicable pilot steam jet system with and without silicate chemistry has been investigated. Treatment using steam alone and steam with silicate, resulted in an oxide layer formation with thickness ∼425 nm and ∼160 nm, respectively...

  12. Performance and plasma metabolites of dairy calves fed starter containing sodium butyrate, calcium propionate or sodium monensin.

    Science.gov (United States)

    Ferreira, L S; Bittar, C M M

    2011-02-01

    This study was conducted to examine the influence of supplementation of sodium butyrate, sodium monensin or calcium propionate in a starter diet on the performance and selected plasma metabolites (plasma glucose, non-esterified fatty acids and β-hydroxybutyrate) of Holstein calves during pre- and post-weaning periods. Twenty-four newborn Holstein calves were housed in individual hutches until 10 weeks of life, receiving water free choice, and fed four liters of milk daily. Calves were blocked according to weight and date of birth, and allocated to one of the following treatments, according to the additive in the starter: (i) sodium butyrate (150 g/kg); (ii) sodium monensin (30 mg/kg); and (iii) calcium propionate (150 g/kg). During 10 weeks, calves received starter ad libitum, while coast cross hay (Cynodon dactylon (L.) pers.) was offered after weaning, which occurred at the 8th week of age. Weekly, calves were weighted and evaluated for body measurements. Blood samples were taken weekly after the fourth week of age, 2 hours after the morning feeding, for determination of plasma metabolites. No differences were observed among treatments for starter or hay intake, BW and daily gain of the animals. Mean concentrations of selected plasma metabolites were similar in calves fed a starter supplemented with sodium butyrate, sodium monensin and calcium propionate. There was significant reduction in the concentrations of plasma glucose as calves aged. The inclusion of sodium butyrate, calcium propionate or sodium monensin as additives in starter feeds resulted in equal animal performance, before and after weaning, suggesting that sodium monensin may be replaced by organic acid salts.

  13. 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.

  14. Neocortical GABA release at high intracellular sodium and low extracellular calcium: an anti-seizure mechanism.

    Science.gov (United States)

    Rassner, Michael P; Moser, Andreas; Follo, Marie; Joseph, Kevin; van Velthoven-Wurster, Vera; Feuerstein, Thomas J

    2016-04-01

    In epilepsy, the GABA and glutamate balance may be disrupted and a transient decrease in extracellular calcium occurs before and during a seizure. Flow Cytometry based fluorescence activated particle sorting experiments quantified synaptosomes from human neocortical tissue, from both epileptic and non-epileptic patients (27.7% vs. 36.9% GABAergic synaptosomes, respectively). Transporter-mediated release of GABA in human and rat neocortical synaptosomes was measured using the superfusion technique for the measurement of endogenous GABA. GABA release was evoked by either a sodium channel activator or a sodium/potassium-ATPase inhibitor when exocytosis was possible or prevented, and when the sodium/calcium exchanger was active or inhibited. The transporter-mediated release of GABA is because of elevated intracellular sodium. A reduction in the extracellular calcium increased this release (in both non-epileptic and epileptic, except Rasmussen encephalitis, synaptosomes). The inverse was seen during calcium doubling. In humans, GABA release was not affected by exocytosis inhibition, that is, it was solely transporter-mediated. However, in rat synaptosomes, an increase in GABA release at zero calcium was only exhibited when the exocytosis was prevented. The absence of calcium amplified the sodium/calcium exchanger activity, leading to elevated intracellular sodium, which, together with the stimulation-evoked intracellular sodium increment, enhanced GABA transporter reversal. Sodium/calcium exchange inhibitors diminished GABA release. Thus, an important seizure-induced extracellular calcium reduction might trigger a transporter- and sodium/calcium exchanger-related anti-seizure mechanism by augmenting transporter-mediated GABA release, a mechanism absent in rats. Uniquely, the additional increase in GABA release because of calcium-withdrawal dwindled during the course of illness in Rasmussen encephalitis. Seizures cause high Na(+) influx through action potentials. A

  15. Laser Sintered Magnesium-Calcium Silicate/Poly-ε-Caprolactone Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Kuo-Yang Tsai

    2017-01-01

    Full Text Available In this study, we manufacture and analyze bioactive magnesium–calcium silicate/poly-ε-caprolactone (Mg–CS/PCL 3D scaffolds for bone tissue engineering. Mg–CS powder was incorporated into PCL, and we fabricated the 3D scaffolds using laser sintering technology. These scaffolds had high porosity and interconnected-design macropores and structures. As compared to pure PCL scaffolds without an Mg–CS powder, the hydrophilic properties and degradation rate are also improved. For scaffolds with more than 20% Mg–CS content, the specimens become completely covered by a dense bone-like apatite layer after soaking in simulated body fluid for 1 day. In vitro analyses were directed using human mesenchymal stem cells (hMSCs on all scaffolds that were shown to be biocompatible and supported cell adhesion and proliferation. Increased focal adhesion kinase and promoted cell adhesion behavior were observed after an increase in Mg–CS content. In addition, the results indicate that the Mg–CS quantity in the composite is higher than 10%, and the quantity of cells and osteogenesis-related protein of hMSCs is stimulated by the Si ions released from the Mg–CS/PCL scaffolds when compared to PCL scaffolds. Our results proved that 3D Mg–CS/PCL scaffolds with such a specific ionic release and good degradability possessed the ability to promote osteogenetic differentiation of hMSCs, indicating that they might be promising biomaterials with potential for next-generation bone tissue engineering scaffolds.

  16. The effect of obturation technique on the push-out bond strength of calcium silicate sealers.

    Science.gov (United States)

    DeLong, Christopher; He, Jianing; Woodmansey, Karl F

    2015-03-01

    Calcium silicate-based sealers are known to have excellent sealing ability and bioactivities. They are typically recommended to be used in a single-cone (SC) technique. No studies have evaluated the effects of the thermoplastic obturation technique on the dentin interface of these sealers. The purpose of this study was to evaluate the push-out bond strengths of MTA Plus Sealer (Avalon Biomed Inc, Bradenton, FL) and EndoSequence BC Sealer (BC; Brasseler USA, Savannah, GA) when they were used in a thermoplastic technique. Fifty single-rooted human extracted teeth were randomly divided into 5 groups (n = 10), instrumented, and obturated with the SC technique or continuous wave (CW) technique: group 1, BC-SC; group 2, BC-CW; group 3, MTA Plus-SC; group 4, MTA Plus-CW; and group 5, AH Plus (Dentsply DeTrey, Konstanz, Germany)-CW. The roots were sectioned into 1.0-mm-thick slices, and bond strengths were measured using a standardized push-out test. The mode of failure was determined by visual inspection under magnification. The MTA Plus-CW had statistically significant lower bond strengths than all other groups. The BC-SC group had statistically higher bond strengths than the MTA Plus-SC and AH Plus-CW groups. No significant differences were seen among the other groups. Modes of failure were predominately cohesive or mixed except for group 4 (ie, MTA Plus-CW) in which nearly half the specimens had no visible sealer. BC and MTA Plus sealer showed favorable bond strengths when used in an SC technique. The CW obturation technique decreased the bond strengths of these sealers. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Effect of Different Irrigation Solutions on the Colour Stability of Three Calcium Silicate-Based Materials

    Directory of Open Access Journals (Sweden)

    Sobhnamayan F

    2017-06-01

    Full Text Available Abstract: Statement of Problem: Previous studies have shown discoloration of mineral trioxide aggregate (MTA in contact with root canal irrigation solutions. However, there are limited data on colour stability of other calcium silicate–based materials (CSMs. Objectives: This in vitro study aimed to evaluate the colour stability of three CSMs in contact with different irrigation solutions. Materials and Methods: Three CSMs including White MTA (wMTA Angelus, calcium enriched mixture (CEM, and Biodentine were assessed in this study. Forty five samples of each material were mixed according to the manufactures’ instructions and then placed in silicone tubes. After 24 hours, the materials were removed from the moulds and 9 samples of each material left dry or immersed in normal saline, 5% sodium hypochlorite (NaOCL, 2% chlorhexidinegluconate (CHX, or 17%EDTA for 24 hours. Colour changes were measured with a spectrophotometer. Data were evaluated with 2-way analysis of variance, one way analysis of variance and Tukey post hoc tests. Results: The highest discoloration of all materials was observed after contact with CHX. In the MTA Angelus and CEM cement groups, significant differences were observed between CHX and NaOCl and also between these two irrigants with the other three irrigants (p < 0.05. In the Biodentine group, CHX created statistically significant discoloration compared to other irrigants (p < 0.05. Only wMTA Angelus showed a significantly higher discoloration in contact with EDTA compared to normal saline and dry condition (p < 0.05. wMTA Angelus showed a significantly higher colour change compared with CEM cement and Biodentine after contact with NaOCl, CHX, and EDTA (p < 0.05. Conclusions: The contact of wMTA, CEM cement, and Biodentine with CHX should be avoided because this leads to severe discoloration. Contact with sodium hypochlorite also leads to discoloration of wMTA and CEM cements. Among of the three tested materials, w

  18. Characterization of the Bonds Developed between Calcium Silicate Hydrate and Polycarboxylate-Based Superplasticizers with Silyl Functionalities

    KAUST Repository

    Orozco, Carlos A.

    2017-03-24

    Major developments in concrete technology have been achieved with the use of polycarboxylate-based superplasticizers (PCEs) to improve the concrete rheology without increasing the mix water content. Currently, it is possible to control the fluidity of the fresh concrete and obtain stronger and more durable structures. Therefore, there is a strong incentive to understand the interactions between PCEs and cement hydrates at the atomic scale to design new customized functional PCEs according to the ever-increasing requirements of the concrete industry. Here, the bonding types generated between a PCE with silyl functionalities (PCE-Sil) and a synthetic calcium silicate hydrate (C-S-H) are analyzed using XRD, 29Si NMR spectroscopy, and synchrotron-based techniques, such as NEXAFS and EXAFS. The results indicated that the carboxylic groups present in PCE-Sil interact by a ligand-type bond with calcium, which modified not only the symmetry and coordination number of the calcium located at the surface of C-S-H but also the neighboring silicon atoms of the C-S-H. In addition, the silyl functionalities of the PCE-Sil generated covalent bonds through siloxane bridges between the silanol groups of PCE-Sil and the nonbonding oxygen located at the dimeric sites in C-S-H, forming new bridging silicon sites and subsequently increasing the silicate polymerization.

  19. Characterization of the Bonds Developed between Calcium Silicate Hydrate and Polycarboxylate-Based Superplasticizers with Silyl Functionalities.

    Science.gov (United States)

    Orozco, Carlos A; Chun, Byong W; Geng, Guoqing; Emwas, Abdul H; Monteiro, Paulo J M

    2017-04-11

    Major developments in concrete technology have been achieved with the use of polycarboxylate-based superplasticizers (PCEs) to improve the concrete rheology without increasing the mix water content. Currently, it is possible to control the fluidity of the fresh concrete and obtain stronger and more durable structures. Therefore, there is a strong incentive to understand the interactions between PCEs and cement hydrates at the atomic scale to design new customized functional PCEs according to the ever-increasing requirements of the concrete industry. Here, the bonding types generated between a PCE with silyl functionalities (PCE-Sil) and a synthetic calcium silicate hydrate (C-S-H) are analyzed using XRD, (29)Si NMR spectroscopy, and synchrotron-based techniques, such as NEXAFS and EXAFS. The results indicated that the carboxylic groups present in PCE-Sil interact by a ligand-type bond with calcium, which modified not only the symmetry and coordination number of the calcium located at the surface of C-S-H but also the neighboring silicon atoms of the C-S-H. In addition, the silyl functionalities of the PCE-Sil generated covalent bonds through siloxane bridges between the silanol groups of PCE-Sil and the nonbonding oxygen located at the dimeric sites in C-S-H, forming new bridging silicon sites and subsequently increasing the silicate polymerization.

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

    Science.gov (United States)

    Zemkova, Hana; Tomić, Melanija; Kucka, Marek; Aguilera, Greti; Stojilkovic, Stanko S

    2016-04-01

    Transgenic mice expressing the tdimer2(12) form of Discosoma red fluorescent protein under control of the proopiomelanocortin gene's regulatory elements are a useful model for studying corticotrophs. Using these mice, we studied the ion channels and mechanisms controlling corticotroph excitability. Corticotrophs were either quiescent or electrically active, with a 22-mV difference in the resting membrane potential (RMP) between the 2 groups. In quiescent cells, CRH depolarized the membrane, leading to initial single spiking and sustained bursting; in active cells, CRH further facilitated or inhibited electrical activity and calcium spiking, depending on the initial activity pattern and CRH concentration. The stimulatory but not inhibitory action of CRH on electrical activity was mimicked by cAMP independently of the presence or absence of arachidonic acid. Removal of bath sodium silenced spiking and hyperpolarized the majority of cells; in contrast, the removal of bath calcium did not affect RMP but reduced CRH-induced depolarization, which abolished bursting electrical activity and decreased the spiking frequency but not the amplitude of single spikes. Corticotrophs with inhibited voltage-gated sodium channels fired calcium-dependent action potentials, whereas cells with inhibited L-type calcium channels fired sodium-dependent spikes; blockade of both channels abolished spiking without affecting the RMP. These results indicate that the background voltage-insensitive sodium conductance influences RMP, the CRH-depolarization current is driven by a cationic conductance, and the interplay between voltage-gated sodium and calcium channels plays a critical role in determining the status and pattern of electrical activity and calcium signaling.

  1. [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).

  2. Synthesis, mechanical properties, and in vitro biocompatibility with osteoblasts of calcium silicate-reduced graphene oxide composites.

    Science.gov (United States)

    Mehrali, Mehdi; Moghaddam, Ehsan; Shirazi, Seyed Farid Seyed; Baradaran, Saeid; Mehrali, Mohammad; Latibari, Sara Tahan; Metselaar, Hendrik Simon Cornelis; Kadri, Nahrizul Adib; Zandi, Keivan; Osman, Noor Azuan Abu

    2014-03-26

    Calcium silicate (CaSiO3, CS) ceramics are promising bioactive materials for bone tissue engineering, particularly for bone repair. However, the low toughness of CS limits its application in load-bearing conditions. Recent findings indicating the promising biocompatibility of graphene imply that graphene can be used as an additive to improve the mechanical properties of composites. Here, we report a simple method for the synthesis of calcium silicate/reduced graphene oxide (CS/rGO) composites using a hydrothermal approach followed by hot isostatic pressing (HIP). Adding rGO to pure CS increased the hardness of the material by ∼40%, the elastic modulus by ∼52%, and the fracture toughness by ∼123%. Different toughening mechanisms were observed including crack bridging, crack branching, crack deflection, and rGO pull-out, thus increasing the resistance to crack propagation and leading to a considerable improvement in the fracture toughness of the composites. The formation of bone-like apatite on a range of CS/rGO composites with rGO weight percentages ranging from 0 to 1.5 has been investigated in simulated body fluid (SBF). The presence of a bone-like apatite layer on the composite surface after soaking in SBF was demonstrated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The biocompatibility of the CS/rGO composites was characterized using methyl thiazole tetrazolium (MTT) assays in vitro. The cell adhesion results showed that human osteoblast cells (hFOB) can adhere to and develop on the CS/rGO composites. In addition, the proliferation rate and alkaline phosphatase (ALP) activity of cells on the CS/rGO composites were improved compared with the pure CS ceramics. These results suggest that calcium silicate/reduced graphene oxide composites are promising materials for biomedical applications.

  3. Tooth Discoloration Induced by Different Calcium Silicate-based Cements: A Systematic Review of In Vitro Studies.

    Science.gov (United States)

    Możyńska, Joanna; Metlerski, Marcin; Lipski, Mariusz; Nowicka, Alicja

    2017-10-01

    On the basis of many clinical observations, some calcium silicate-based cements have a high potential for staining tooth tissue. This feature greatly limits the use of those cements, particularly for anterior teeth. This review aimed to provide a systematic evaluation of published in vitro studies to determine the effect of different calcium silicate-based cements on dental tissue discoloration. This literature review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. The literature search was based on all publications without a year limit. The last search was performed on October 22, 2016. An electronic search was performed on MEDLINE (PubMed), Cochrane, and Scopus. The articles were selected to address the following research question: Which materials based on calcium silicate-based cements have hard tissue staining potential? The necessary information was extracted by 2 authors independently using a standardized form. The search resulted in 390 titles from all databases. Twenty-three studies met the inclusion criteria. Most of the studies exhibited a moderate risk of bias. The results indicated that some materials showed a strong potential for staining, including gray and white MTA Angelus (Londrina, PR, Brazil), gray and white ProRoot MTA (Dentsply, Tulsa, OK), and Ortho MTA (BioMTA, Seoul, Korea). Individual study results showed that Biodentine (Septodont, Saint Maur des Fosses, France), Retro MTA (BioMTA), Portland cement, EndoSequence Root Repair Material (Brasseler USA, Savannah, GA), Odontocem (Australian Dental Manufacturing, Brisbane, Australia), MM-MTA (Micro Mega, Besancon Cedex, France), and MTA Ledermix (Riemser Pharma GmbH, Greiswald-Insel Riems, Germany) were materials with the smallest staining potential. This review clearly showed that some calcium silicate-based cements have a high potential for staining hard tissue. On the other hand, some showed only a small change in color, which was

  4. Effect of Hydration and Confinement on Micro-Structure of Calcium-Silicate-Hydrate Gels

    Science.gov (United States)

    Gadde, Harish Kumar

    Calcium-silicate-hydrate(C-S-H) gel is a primary nano-crystalline phase present in hydrated Ordinary Portland Cement (OPC) responsible for its strength and creep behavior. Our reliance on cement for infrastructure is global, and there is a need to improve infrastructure life-times. A way forward is to engineer the cement with more durability and long-term strength. The main purpose of this research is to quantify the micro-structure of C-S-H to see if cement can be engineered at various length scales to improve long-term behavior by spatial arrangement. We investigate the micro-structure evolution of C-S-H in cement as a function of hydration time and confinement. Scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to quantify the material and spatial properties of C-S-H as a function of hydration time. The data obtained from these experiments was used to identify C-S-H phases in cement sample. Pair Distribution Function (PDF) analysis of HD C-S-H phase with different hydration times was done at Advanced Photon Source, Argonne National Laboratory, beamline 11-ID-B. Only nonlinear trends in the atomic ordering of C-S-H gel as a function of hydration time were observed. Solid state 29Si Nuclear Magnetic Resonance (NMR) was used to quantify the effect of confinement on two types of C-S-H: white cement C-S-H and synthetic C-S-H. NMR spectra revealed that there is no significant difference in the structure of C-S-H due to confinement when compared with unconfined C-S-H. It is also found that there is significant difference in the Si environments of these two types of C-S-H. Though it does seem possible to engineer the cement on atomic scales, all these studies reveal that engineering cement on such a scale requires a more statistically accurate understanding of intricate structure of C-S-H than is currently available.

  5. How effectively do hydraulic calcium-silicate cements re-mineralize demineralized dentin.

    Science.gov (United States)

    Li, Xin; De Munck, Jan; Van Landuyt, Kirsten; Pedano, Mariano; Chen, Zhi; Van Meerbeek, Bart

    2017-04-01

    To characterize the chemical interplay and to quantify the re-mineralization potential of hydraulic calcium-silicate cements (hCSCs) at demineralized dentin. Pairs of class-I cavities were prepared in non-carious human third molars. One dentin cavity was demineralized with 10% formic acid (5h); the other served as control. The cavities were filled with two resin-free hCSCs (Biodentine, Septodont; ProRoot MTA, Dentsply Sirona) or one resin-based hCSC (TheraCal LC, Bisco). After 1-week, 1-, 3-, and 6-month storage in simulated body fluid (SBF), polished specimen cross-sections were chemically characterized using Field-emission-gun Electron Probe Micro-Analysis (Feg-EPMA) and micro-Raman spectroscopy (μRaman). Feg-EPMA line-scans and elemental mappings confirmed early re-mineralization induced by all three hCSCs at 1week. The relative depth and intensity of re-mineralization were for the resin-free hCSCs in the range of 50.5%-84.8% and 68.1%-89.2%, respectively. Re-mineralization did not significantly differ for the storage periods (p>0.05). Significantly less re-mineralization was achieved by the resin-based hCSC TheraCal LC that reached only at 6months a re-mineralization level that was no longer significantly different from that achieved by the resin-free hCSCs at 1week (p>0.05). Re-mineralization of intertubular dentin, including tubular occlusion, was observed; Si was occasionally detected to have infiltrated the dentin tubules. Dentin re-mineralization by hCSCs was confirmed using μRaman that revealed an increased phosphate peak at 960cm(-1). hCSCs do re-mineralize demineralized dentin. The resin-free cements induced re-mineralization at a higher speed/intensity than the resin-based hCSC. However, re-mineralization was incomplete for all hCSCs tested, this even at 6months. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Luminescence properties of dysprosium doped calcium magnesium silicate phosphor by solid state reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, Ishwar Prasad, E-mail: ishwarprasad1986@gmail.com [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Chandrakar, Priya; Baghel, R.N.; Bisen, D.P.; Brahme, Nameeta [School of Studies in Physics & Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Tamrakar, Raunak Kumar [Department of Applied Physics, Bhilai Institute of Technology, Durg, C.G. 491001 (India)

    2015-11-15

    Dysprosium doped calcium magnesium silicate (CaMgSi{sub 2}O{sub 6}:Dy{sup 3+}) white light emitting phosphor was synthesized by solid state reaction process. The crystal structure of sintered phosphor was monoclinic structure with space group C2/c. Chemical composition of the sintered CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was confirmed by EDX. The prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was excited from 352 nm and their corresponding emission spectra were recorded at blue (470 nm), yellow (570 nm) and red (675 nm) line due to the {sup 4}F{sub 9/2} → {sup 6}H{sub 15/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 13/2}, {sup 4}F{sub 9/2} → {sup 6}H{sub 11/2} transitions of Dy{sup 3+} ions. The combination of these three emissions constituted as white light confirmed by the Commission Internationale de L'Eclairage (CIE) chromatic coordinate diagram. The possible mechanism of the white light emitting long lasting CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor was also investigated. Investigation on afterglow property show that phosphor held fast and slow decay process. The peak of mechanoluminescence (ML) intensity increases linearly with increasing impact velocity of the moving piston. Thus the present investigation indicates that the local piezoelectricity-induced electron bombardment model is responsible to produce ML in prepared CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor. - Highlights: • The crystal structure of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is consistent with standard monoclinic structure. • CIE coordinates of CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor is suitable as white light emitting phosphor. • The local piezoelectricity-induced electron bombardment model is responsible to produce ML in CaMgSi{sub 2}O{sub 6}:Dy{sup 3+} phosphor.

  7. Clinical and Radiographic Assessment of the Efficacy of Calcium Silicate Indirect Pulp Capping

    Science.gov (United States)

    Hashem, D.; Mannocci, F.; Patel, S.; Manoharan, A.; Brown, J.E.; Watson, T.F.

    2015-01-01

    The aims of this study were to assess the effectiveness of calcium silicate cement (Biodentine) versus glass ionomer cement (GIC; control group) as indirect pulp capping materials in patients with reversible pulpitis and to compare the effectiveness of cone beam computed tomography (CBCT) versus periapical (PA) radiographs in detecting PA changes at baseline (T0) and at 12 mo (T12) postoperatively. Seventy-two restorations (36 Biodentine, 36 Fuji IX) were placed randomly in 53 patients. CBCT/PA radiographs were taken at T0 and T12. Two calibrated examiners assessed the presence/absence and increase/decrease in the size of existing PA radiolucencies under standardized conditions. The Kappa coefficient evaluated statistically the effectiveness of CBCT versus PA radiographs in detecting PA changes. Chi-square/Mann-Whitney tests were used to evaluate the association between PA changes in CBCT with various clinical measures. Significance was predetermined at α = 0.05. Clinical success rates for Biodentine and Fuji IX GIC were 83.3%. CBCT was significantly more effective in detecting PA radiolucencies compared with radiographs (P = 0.0069). Of the teeth, 65.4% and 90.4% were deemed healthy using CBCT and PA radiographs, respectively, at T12. Healing/healed rates were 17.3%/0%, while new/progressed radiolucency were 30.8%/9.6% with CBCT/PA radiographs, respectively. Seventy-one percent of healed lesions had received Biodentine; 88% of new/progressed lesions received Fuji IX GIC. Teeth presenting with an initial CBCT PA lesion had a failure rate of 63%, whereas teeth with no initial lesion had a failure rate of 16%. Although no statistically significant difference was detected in the clinical efficacy of Biodentine/Fuji IX when used as indirect pulp capping materials in patients with reversible pulpitis, CBCT showed a significant difference in that most healed CBCT lesions had received Biodentine while most that did not heal received Fuji IX. Longer-term follow-up is

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

    Directory of Open Access Journals (Sweden)

    Giovana Longo-Silva

    2014-06-01

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

  9. Inorganic polymers from laterite using activation with phosphoric acid and alkaline sodium silicate solution: Mechanical and microstructural properties

    Energy Technology Data Exchange (ETDEWEB)

    Lassinantti Gualtieri, Magdalena, E-mail: magdalena.gualtieri@unimore.it [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Romagnoli, Marcello [Dipartimento di Ingegneria " Enzo Ferrari" , Università degli studi di Modena e Reggio Emilia, Via Vignolese 905/a, I-41125 Modena (Italy); Pollastri, Simone; Gualtieri, Alessandro F. [Dipartimento di Scienze Chimiche e Geologiche, Università degli studi di Modena e Reggio Emilia, Via S. Eufemia 19I, I-41121 Modena (Italy)

    2015-01-15

    Geopolymers from laterite, an iron-rich soil available in developing countries, have great potential as building materials. In this work, laterite from Togo (Africa) was used to prepare geopolymers using both phosphoric acid and alkaline sodium silicate solution. Microstructural properties were investigated by scanning electron microscopy, X-ray powder diffraction and mercury porosimetry, whereas thermal properties were evaluated by thermal analyses. The local environment of iron was studied by X-ray Absorption Spectroscopy (XANES region). The mechanical properties were determined. Modulus of Rupture and Young's modulus fell in the ranges 3.3–4.5 MPa and 12–33 GPa, respectively, rendering the materials good candidates for construction purposes. Heating above 900 °C results in weight-gain, presumably due to iron redox reactions. X-ray Absorption Spectroscopy data evidence changes in the chemical and structural environments of iron following thermal treatment of geopolymers. These changes indicate interaction between the geopolymer structure and iron during heating, possibly leading to redox properties. -- Highlights: •Geopolymerization of laterite is promising for fabrication of building materials. •Both phosphoric acid and alkaline sodium silicate solution can be used for activation. •Thermally activated redox properties of the inorganic polymers were observed.

  10. Structural study and crystallography of the major compound of anhydrous cement: tri-calcium silicate; Etude structurale et cristallographie du compose majoritaire du ciment anhydre: le silicate tricalcique

    Energy Technology Data Exchange (ETDEWEB)

    Noirfontaine, M.N. de

    2000-01-01

    Anhydrous (Portland) cement is mainly composed of a synthetic material, the clinker, whose major compound is tri-calcium silicate (Ca{sub 3}SiO{sub 5}), often referred as C{sub 3}S with the compact oxides notations, C = CaO et S = SiO{sub 2}. The polymorphism of C{sub 3}S, still not well known, is the main subject of the thesis. Various crystal structures (rhombohedral R, monoclinic M1, M2, M3 and triclinic T1, T2, T3) can be found, depending on temperature and impurities. The only known structures are T1, M1 and M3, involving large unit cells with an orientational disorder of silicate tetrahedra. The single crystal studies exhibit no clear relation between the various polymorphs. Starting from known results from literature single crystal experiments, we establish the metric and structural relations between the different structures. Averaged structures for the T1, M1 and M3 polymorphs are proposed, together with all the matrices of transformation between the unit cells. We also introduce new 1-D, 2-D, and 3-D structural units, which make easier the understanding of the structures of C{sub 3}S, with the result of a better description of the orientational disorder. The effects of impurities on the structure are discussed. In industrial clinkers, impurities stabilize mainly M1 and M3 monoclinic forms. We propose a space group (Pc) and two structural models (a superstructure and an approximate averaged structure) for the M1 form. All the models are validated on synthetic compounds (M3, M2, M1 et T1) and industrial clinkers analysed by X-Ray powder diffraction with Rietveld analysis. (author)

  11. Effect of composition and pressure on the shear strength of sodium silicate glasses: An atomic scale simulation study

    Science.gov (United States)

    Molnár, Gergely; Ganster, Patrick; Tanguy, Anne

    2017-04-01

    The elastoplastic behavior of sodium silicate glasses is studied at different scales as a function of composition and pressure, with the help of quasistatic atomistic simulations. The samples are first compressed and then sheared at constant pressure to calculate yield strength and permanent plastic deformations. Changes occurring in the global response are then compared to the analysis of local plastic rearrangements and strain heterogeneities. It is shown that the plastic response results from the succession of well-identified localized irreversible deformations occurring in a nanometer-size area. The size and the number of these local rearrangements, as well as the amount of internal deviatoric and volumetric plastic deformation, are sensitive to the composition and to the pressure. In the early stages of the deformation, plastic rearrangements are driven by sodium mobility. Consequently, the elastic yield strength decreases when the sodium content increases, and the same when pressure increases. Finally, good correlation was found between global and local stress-strain relationships, reinforcing again the role of sodium ions as local initiators of the plastic behavior observed at larger scales.

  12. 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...... seen in these animals, the final proof of concept was done on pregnant dry cows fed a supplement of synthetic sodium zeolite A from 4 weeks before expected calving until calving. By analysis of blood calcium levels, this supplementation was shown to have a stabilizing effect during the critical period...

  13. Interaction of calcium silicate hydrates (C-S-H), the main components of cement, with alkaline chlorides, analogy with clays; Interaction des silicates de calcium hydrates, principaux constituants du ciment, avec les chlorures d'alcalins. Analogie avec les argiles

    Energy Technology Data Exchange (ETDEWEB)

    Viallis-Terrisse, H

    2000-10-06

    This work, belonging to a more general study on the structure and reactivity of cement, deals with the experimental and theoretical analysis of the interaction of alkaline chlorides with calcium silicate hydrates (C-S-H), the main components of cement paste. The interaction of alkaline cations with C-S-H is interfacial, involving both electrostatic and surface complexation mechanisms. The C-S-H surface is constituted of silanol sites, partially dissociated due to the high pH of the interstitial solution. The calcium ions, present in large amounts in the equilibrium solution of C-S-H, constitute potential determining ions for the C-S-H surface. The alkaline ions seem to compete with calcium for the same surface sites. The adsorption isotherms show that caesium presents a better affinity than sodium and lithium for the C-S-H surface. Moreover, solid-state NMR suggests that caesium forms with the surface sites inner-sphere complexes, whereas sodium seems to keep its hydration sphere. These results are in agreement with zeta potential measurements, which let suppose a specific adsorption of caesium ions, and an indifferent behaviour of both other alkaline ions. A model for the C-S-H surface was proposed, from the electric double layer model, and mass action laws expressing the complexation of the different ionic species with the silanol sites. The whole study relies on a structural analogy with smectites, some clays presenting well-known cationic adsorption properties. The structural similarity between both minerals is enhanced by some similarities of reactivity, though significant behaviour differences could also be noted. (author)

  14. Success Rates of Pulpotomies in Primary Molars Using Calcium Silicate-Based Materials: A Randomized Control Trial

    Directory of Open Access Journals (Sweden)

    Yeliz Guven

    2017-01-01

    Full Text Available Objective. The aim of this study was to evaluate and compare, both clinically and radiographically, the effects of calcium silicate-based materials (i.e., ProRoot MTA [PR-MTA], MTA-Plus [MTA-P], and Biodentine [BD] and ferric sulfate [FS] in pulpotomy of primary molars. Materials and Methods. In this randomized clinical trial, 29 healthy 5- to 7-year-old children with at least four carious primary molars with no clinical or radiographic evidence of pulp degeneration were enrolled. The pulpotomy agents were assigned as follows: Group 1: BD; Group 2: MTA-P; Group 3: PR-MTA; and Group 4: FS. Clinical and radiographic evaluations were performed at 6, 12, and 24 months. Data were analyzed using chi-square tests. Results. Total success rates at 24 months were 82.75%, 86.2%, 93.1%, and 75.86%, respectively. No statistically significant differences in total success rates were observed among the groups at 6-, 12-, and 24-month follow-ups. When the groups were compared according to follow-up times, the success rates in each group did not vary significantly among the 6–12-month, 6–24-month, or 12–24-month periods (p>0.05. Conclusion. Although the success rates of BD, MTA-P, MTA-PR, and FS did not differ significantly, calcium silicate-based materials appeared to be more appropriate than FS in clinical practice.

  15. Success Rates of Pulpotomies in Primary Molars Using Calcium Silicate-Based Materials: A Randomized Control Trial.

    Science.gov (United States)

    Guven, Yeliz; Aksakal, Sermin Dicle; Avcu, Nilufer; Unsal, Gulcan; Tuna, Elif Bahar; Aktoren, Oya

    2017-01-01

    The aim of this study was to evaluate and compare, both clinically and radiographically, the effects of calcium silicate-based materials (i.e., ProRoot MTA [PR-MTA], MTA-Plus [MTA-P], and Biodentine [BD]) and ferric sulfate [FS] in pulpotomy of primary molars. In this randomized clinical trial, 29 healthy 5- to 7-year-old children with at least four carious primary molars with no clinical or radiographic evidence of pulp degeneration were enrolled. The pulpotomy agents were assigned as follows: Group 1: BD; Group 2: MTA-P; Group 3: PR-MTA; and Group 4: FS. Clinical and radiographic evaluations were performed at 6, 12, and 24 months. Data were analyzed using chi-square tests. Total success rates at 24 months were 82.75%, 86.2%, 93.1%, and 75.86%, respectively. No statistically significant differences in total success rates were observed among the groups at 6-, 12-, and 24-month follow-ups. When the groups were compared according to follow-up times, the success rates in each group did not vary significantly among the 6-12-month, 6-24-month, or 12-24-month periods (p > 0.05). Although the success rates of BD, MTA-P, MTA-PR, and FS did not differ significantly, calcium silicate-based materials appeared to be more appropriate than FS in clinical practice.

  16. STUDY OF SODIUM, POTASSIUM, AND CALCIUM SALTS INFLUENCE ON PROTEIN STABILITY BY DIFFERENTIAL SCANNING CALORIMETRY

    Directory of Open Access Journals (Sweden)

    E. K. Tunieva

    2016-01-01

    Full Text Available Abstract Study of protein stability depending on the various technological factors allows to directionally adjust the physicochemical properties of raw meat and the quality of finished meat products. The paper investigates the possibility of using the DSC to study the influence of monovalent and divalent salts on protein thermal stability. In order to determine the effect of sodium chloride and its substitutes, potassium and calcium salts, on the thermal stability of proteins, the studies were carried out with grinded pork longissimus muscle samples salted with sodium chloride at level of 2.0% and with salt compositions containing reduced by 50% level of sodium chloride (a mixture of sodium and potassium chlorides; a mixture of sodium, potassium, and calcium chlorides using the differential scanning calorimeter DSC Q 2000 in the temperature range of 5 °C to 100 °C and the temperature change rate of 1 K/min. It was found that the addition of potassium chloride instead of 50% of sodium chloride had no significant effect on actin and myosin resistance to thermal denaturation. Meat salting using the mixture of sodium, potassium, and calcium chlorides resulted in decrease of myofibrillar proteins stability indicating the destabilizing effect of calcium on actin and myosin. A negative correlation between the magnitude of the ionic strength and the temperature of myosin and actin denaturation has been found. The correlation coefficients were minus 0.99 and minus 0.95 for myosin and actin respectively. Reduction of denaturation temperature for myofibrillar proteins in the presence of calcium chloride opens perspectives to study the possibility of heat treatment at lower temperatures for meat products with reduced sodium content.

  17. 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

  18. Effects of extracellular calcium and sodium on depolarization-induced automaticity in guinea pig papillary muscle.

    Science.gov (United States)

    Katzung, B G

    1975-07-01

    Regenerative discharge of action potentials is induced in mammalian papillary muscles by passage of small depolarizing currents. In this paper, the effects of various extracellular calcium and sodium concentrations and of tetrodotoxin on this phenomenon were studied in guinea pig papillary muscles in a sucrose gap chamber. Phase 4 diastolic depolarization was found to be associated with an increase in membrane resistance. The slope of phase 4 depolarization was decreased by reductions in extracellular calcium or sodium concentration. The range of maximum diastolic potentials and the thresholds from which regenerative potentials arose were reduced, especially at the positive limit of potentials, by a reduction in either ion. It was concluded that both calcium and sodium influence diastolic depolarization and participate in the regenerative action potentials of depolarization-induced ventricular automaticity.

  19. Electrophoretic deposition of calcium silicate-reduced graphene oxide composites on titanium substrate

    DEFF Research Database (Denmark)

    Mehrali, Mehdi; Akhiani, Amir Reza; Talebian, Sepehr

    2016-01-01

    silicate-reduced graphene oxide (CS-rGO) composites were synthesized, using an in situ hydrothermal method. CS nanowires were uniformly decorated on the rGO, with an appropriate interfacial bonding. The CS-rGO composites behaved like hybrid composites when deposited on a titanium substrate by cathodic...

  20. Repassivation Potential of Alloy 22 in Sodium and Calcium Chloride Brines

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-11

    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.

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

    OpenAIRE

    Neithercut, W D

    1989-01-01

    The effect of increasing the calcium, magnesium and sodium concentration in gall bladder bile samples from 21 patients with gall stones and nine controls on the in vitro rate of formation of cholesterol microcrystals and numbers of cholesterol microcrystals formed was examined. Addition of these cations to raise the mean maximum concentration of calcium ions to 19.8 mmol/l, of magnesium ions to 20 mmol/l and sodium ions to 998 mmol/l did not trigger nucleation in control bile samples or sampl...

  2. Parathyroid hormone, calcium, and sodium bridging between osteoporosis and hypertension in postmenopausal Korean women.

    Science.gov (United States)

    Park, Jee Soo; Choi, Soo Beom; Rhee, Yumie; Chung, Jai Won; Choi, Eui-Young; Kim, Deok Won

    2015-05-01

    The coexistence of osteoporosis and hypertension, which are considered distinct diseases, has been widely reported. In addition, daily intake of calcium and sodium, as well as parathyroid hormone levels (PTH), is known to be associated with osteoporosis and hypertension. This study aimed to determine the association of low calcium intake, high sodium intake, and PTH levels with osteoporosis and hypertension in postmenopausal Korean women. Data for postmenopausal Korean women aged 50 years or older were obtained from the Korea National Health and Nutrition Examination Survey 2008-2011. Osteoporosis was diagnosed using dual energy X-ray absorptiometry, while hypertension was diagnosed using blood pressure data. The odds ratios for osteoporosis and hypertension were calculated using logistic regression analysis for quartiles of the daily calcium intake, daily sodium intake, and PTH levels. Women with hypertension had a high coexistence of osteoporosis (43.6 vs. 36.5 %; P = 0.022), and vice versa (21.1 vs. 16.6 %; P = 0.022). PTH was significantly associated with osteoporosis and hypertension, and a high intake of calcium was strongly correlated with a low incidence of osteoporosis. This is the first study to report the characteristics of postmenopausal Korean women who have high dietary sodium intake and low dietary calcium intake, in association with the incidence of osteoporosis and hypertension. Osteoporosis and hypertension were strongly associated with each other, and PTH appears to be a key mediator of both diseases, suggesting a possible pathogenic link.

  3. Statistical Approach for Assessing the Influence of Calcium Silicate and HPMC on the Formulation of Novel Alfuzosin Hydrochloride Mucoadhesive-Floating Beads as Gastroretentive Drug Delivery Systems

    OpenAIRE

    Fahmy, Rania Hassan

    2012-01-01

    Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the “all or none” gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared...

  4. Preparation and characterization of bioactive and degradable composites containing ordered mesoporous calcium-magnesium silicate and poly(L-lactide)

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Jiajin [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China); Dong, Xieping, E-mail: jxzhyxh@163.com [Department of Orthopaedic Surgery, Jiangxi People' s Hospital, Nanchang 330006 (China); Ma, Xuhui [Polymer Science (Shenzhen) New Materials Co., Ltd., Shenzhen 518101 (China); Tang, Songchao, E-mail: schtang@ecust.edu.cn [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China); Wu, Zhaoying; Xia, Ji; Wang, Quanxiang; Wang, Yutao; Wei, Jie [Key Shanghai Key Laboratory of Advanced Polymeric Materials, East China University of Science and Technology, Shanghai 200237 (China)

    2014-10-30

    Highlights: • Mesoporous calcium-magnesium silicate and poly(L-lactide) composite was fabricated. • The composite has good hydrophilicity, in vitro degradation and bioactivity. • The composite could support cell attachment, proliferation and differentiation. - Abstract: Polylactide (PLA) and its copolymers have been widely used for bone tissue regeneration. In this study, a bioactive composite of ordered mesoporous calcium–magnesium silicate (m-CMS) and poly(L-lactide) (PLLA) was fabricated by melt blending method. The results indicated that the m-CMS particles were entrapped by polymer phase, and crystallinity of PLLA significantly decreased while the thermal stability of the m-CMS/PLLA composites was not obviously affected by addition of the m-CMS into PLLA. In addition, compared to PLLA, incorporation of the m-CMS into PLLA significantly improved the hydrophilicity, in vitro degradability and bioactivity (apatite-formation ability) of the m-CMS/PLLA composite, which were m-CMS content dependent. Moreover, it was found that incorporation of the m-CMS into PLLA could neutralize the acidic degradation by-products and thus compensated for the decrease of pH value. In cell culture experiments, the results showed that the composite enhanced attachment, proliferation and alkaline phosphatase activity (ALP) of MC3T3-E1 cells, which were m-CMS content dependent. The results indicated that the addition of bioactive materials to PLLA could result in a composite with improved properties of hydrophilicity, degradability, bioactivity and cytocompatibility.

  5. Preparation and rebinding properties of protein-imprinted polysiloxane using mesoporous calcium silicate grafted non-woven polypropylene as matrix.

    Science.gov (United States)

    Kan, Bohong; Feng, Lingzhi; Zhao, Kongyin; Wei, Junfu; Zhu, Dunwan; Zhang, Linhua; Ren, Qian

    2016-03-01

    Calcium silicate particle containing mesoporous SiO2 (CaSiO3@SiO2) was grafted on the surface of non-woven polypropylene. The PP non-woven grafted calcium silicate containing mesoporous SiO2 (PP-g-CaSiO3@SiO2) was used as the matrix to prepare bovine serum albumin (BSA) molecularly imprinted polysiloxane (MIP) by using silanes as the functional monomers and BSA as the template. PP non-woven grafted BSA-imprinted polysiloxane (PP-g-CaSiO3@SiO2 MIP) was characterized by scanning electron microscope (SEM), Fourier transform infrared spectometry (FTIR) and drilling string compensator (DSC). Influence factors on the rebinding capacity of the MIP were investigated, such as grafting degree, the pH in treating CaSiO3 and the type and proportion of silanes. The rebinding properties of BSA on PP-g-CaSiO3@SiO2 and MIP were investigated under different conditions. The results indicated that the rebinding capacity of MIP for BSA reached 56.32 mg/g, which was 2.65 times of NIP. The non-woven polypropylene grafted BSA-imprinted polysiloxane could recognize the template protein and the selectivity factor (β) was above 2.4 when using ovalbumin, hemoglobin and γ-globulin as control proteins. The PP-g-CaSiO3@SiO2 MIP has favorable reusability. Copyright © 2015 John Wiley & Sons, Ltd.

  6. A comparative study of de-icing salts (sodium chloride and calcium ...

    African Journals Online (AJOL)

    A greenhouse study was conducted on four roadside plants (Festuca rubra, Lolium perenne, Plantago lanceolata and Trifolium repens) to determine the effect of two de-icing salts {Sodium Chloride (NaCl) and calcium magnesium acetate, (CMA)} on their growth. Plants were grown in pots and supplied with solution of ...

  7. 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

  8. Hydrate sodium calcium aluminosilicate does not reduce rumen lipopolysacharide concentrations in cows

    NARCIS (Netherlands)

    Pilachai, R.; Schonewille, J.T.; Thamrongyoswittayakul, C.; Aiumlamai, S.; Wachirapakorn, C.; Everts, H.; Vlaeminck, B.; Doekes, G.; Hendriks, W.H.

    2014-01-01

    The efficacy of hydrate sodium calcium aluminosilicate (HSCAS) to reduce the concentrations of free lipopolysaccharide (LPS) in rumen fluid of cows was investigated. Six, rumen-fistulated crossbred Holstein, non-pregnant, dry cows were randomly assigned to three experimental rations in a study with

  9. Parabrachial lesions in rats disrupt sodium appetite induced by furosemide but not by calcium deprivation

    Science.gov (United States)

    Grigson, P.S.; Colechio, E.M.; Power, M.L.; Schulkin, J.; Norgren, R.

    2015-01-01

    An appetite for CaCl2 and NaCl occurs in young rats after they are fed a diet lacking Ca or Na, respectively. Bilateral lesions of the parabrachial nuclei (PBN) disrupt normal taste aversion learning and essentially eliminate the expression of sodium appetite. Here we tested whether similar lesions of the PBN would disrupt the calcium-deprivation-induced appetite for CaCl2 or NaCl. Controls and rats with PBN lesions failed to exhibit a calcium-deprivation-induced appetite for CaCl2. Nevertheless, both groups did exhibit a significant calcium-deprivation-induced appetite for 0.5 M NaCl. Thus, while damage to the second central gustatory relay in the PBN disrupts the appetite for 0.5 M NaCl induced by furosemide, deoxycorticosterone acetate, and polyethylene glycol, the sodium appetite induced by dietary CaCl2 depletion remains intact. PMID:25540931

  10. Fluorescent properties of a blue-to green-emitting Ce{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Yoshiyuki, E-mail: kojima.yoshiyuki@nihon-u.ac.jp [Department of Materials and Applied Chemistry, Faculty of Science and Engineering, Nihon University, 1-8, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Numazawa, Masaaki; Umegaki, Tetsuo [Department of Materials and Applied Chemistry, Faculty of Science and Engineering, Nihon University, 1-8, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)

    2012-11-15

    Ce{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor was prepared by heating (830 Degree-Sign C for 30 min) Ce{sup 3+}, Tb{sup 3+} codoped calcium silicate hydrate phosphor formed by liquid-phase reaction. The excitation peak wavelength of the resulting phosphor was 330 nm and the emission peak wavelengths were at 544 nm, attributed to the {sup 5}D{sub 4}{yields}{sup 7}F{sub 5} transition of Tb{sup 3+}, and at 430-470 mm, attributed to Ce{sup 3+}. The intensity ratio of the two peaks could be freely controlled by varying the Tb/Ca atomic ratio of the Ce{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from blue to green. It was clarified that energy transfer exists from Ce{sup 3+} to Tb{sup 3+}. - Graphical abstract: Ce{sup 3+}, Tb{sup 3+} codoped calcium silicate hydrate phosphor was synthesized by liquid-phase reaction. This was heated at 830 Degree-Sign C to obtain a Ce{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor. Under 330 nm excitation, this phosphor showed emission peaks at 430-470 nm and 542 nm. The luminescent color could be continuously changed blue to green with increasing Tb/Ca atomic ratio. It was clarified that electron transfer from Ce{sup 3+} to Tb{sup 3+} is occurring.

  11. Effects of surface application of calcium-magnesium silicate and gypsum on soil fertility and sugarcane yield

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2014-12-01

    Full Text Available Lime application recommendations for amendment of soil acidity in sugarcane were developed with a burnt cane harvesting system in mind. Sugarcane is now harvested in most areas without burning, and lime application for amendment of soil acidity in this system in which the sugarcane crop residue remains on the ground has been carried out without a scientific basis. The aim of this study was to evaluate the changes in soil acidity and stalk and sugar yield with different rates of surface application of calcium, magnesium silicate, and gypsum in ratoon cane. The experiment was performed after the 3rd harvest of the variety SP 81-3250 in a commercial green sugarcane plantation of the São Luiz Sugar Mill (47º 25' 33" W; 21º 59' 46" S, located in Pirassununga, São Paulo, in southeast Brazil. A factorial arrangement of four Ca-Mg silicate rates (0, 850, 1700, and 3400 kg ha-1 and two gypsum rates (0 and 1700 kg ha-1 was used in the experiment. After 12 months, the experiment was harvested and technological measurements of stalk and sugar yield were made. After harvest, soil samples were taken at the depths of 0.00-0.05, 0.05-0.10, 0.10-0.20, 0.20-0.40, and 0.40-0.60 m in all plots, and the following determinations were made: soil pH in CaCl2, organic matter, P, S, K, Ca, Mg, H+Al, Al, Si, and base saturation. The results show that the application of gypsum reduced the exchangeable Al3+ content and Al saturation below 0.05 m, and increased the Ca2+ concentration in the whole profile, the Mg2+ content below 0.10 m, K+ below 0.4 m, and base saturation below 0.20 m. This contributed to the effect of surface application of silicate on amendment of soil acidity reaching deeper layers. From the results of this study, it may be concluded that the silicate rate recommended may be too low, since the greater rates used in this experiment showed greater reduction in soil acidity, higher levels of nutrients at greater depths and an increase in stalk and sugar

  12. Silicato de cálcio como amenizante da toxidez de metais pesados em mudas de eucalipto Calcium silicate to reduce heavy metal toxicity in eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Adriana Maria de Aguiar Accioly

    2009-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito do silicato de cálcio na redução da toxidez de metais pesados no solo para Eucalyptus camaldulensis. Foram utilizadas cinco doses de silicato de cálcio (0, 1,6, 3,2, 4,8 e 6,4 g kg-1, em solos com diferentes graus de contaminação. O experimento foi conduzido em vasos com 1,5 kg de solo, com uma muda por vaso, em esquema fatorial 4x5 (quatro graus de contaminação x cinco doses de silicato. O silicato de cálcio reduziu a toxidez de metais pesados em E.camaldulensis, retardou o aparecimento dos sintomas de toxidez e diminuiu os teores de zinco e cádmio na parte aérea das plantas. Entretanto, não evitou totalmente a depressão no crescimento, nos solos com contaminação elevada. O efeito amenizante do silicato foi crescente com o aumento das doses e mais evidente nos solos com contaminação elevada. O efeito benéfico do silicato de cálcio está relacionado à redução da transferência do zinco para a parte aérea do eucalipto.The objective of this study was to evaluate the effect of calcium silicate to reduce heavy metal toxicity in Eucalyptus camaldulensis seedlings. Five doses of calcium silicate (0, 1.6, 3.2, 4.8, and 6.4 g kg-1 were used in soils with increasing levels of contamination. The experiment was carried out in pots with 1.5 kg of soil, with one plant each, in a 4x5 factorial array (four levels of contamination x five silicate doses. Calcium silicate minimized heavy metal toxicity to E.camaldulensis, delayed the onset of toxicity symptoms, and decreased zinc and cadmium shoot concentrations. However, calcium silicate did not completely overcome the depressive effect upon plant growth in soils with high metal concentrations. Calcium silicate effects increased with increasing doses and were more evident in highly contaminated soils. The beneficial effects of calcium silicate on metal toxicity were highly related to the decrease in zinc translocation to the eucalyptus shoots.

  13. Comparative evaluation of calcium silicate-based dentin substitute (Biodentine?) and calcium hydroxide (pulpdent) in the formation of reactive dentin bridge in regenerative pulpotomy of vital primary teeth: Triple blind, randomized clinical trial

    OpenAIRE

    Navneet Grewal; Rubica Salhan; Nirapjeet Kaur; Hemal Bipin Patel

    2016-01-01

    Background: Considering the biological concerns of calcium hydroxide (CH) as a pulpotomy agent, an alternative silicate based dentin substitute i.e. Biodentine (Ca3SiO5) was evaluated clinically and radiographically. Aims: To evaluate the effectiveness of dentin substitute (Biodentine) in regenerative pulpotomy of vital primary teeth that would giv a biological base to its use in forming reactive dentin bridge and overcoming the drawbacks of calcium hydroxide. Material and Methods: Randomised...

  14. Calcium intercalation into layered fluorinated sodium iron phosphate

    Science.gov (United States)

    Lipson, Albert L.; Kim, Soojeong; Pan, Baofei; Liao, Chen; Fister, Timothy T.; Ingram, Brian J.

    2017-11-01

    The energy density and cost of battery systems, relative to the current state-of-the art, can be improved by developing alternative chemistries utilizing multivalent working ions such as calcium. Many challenges must be overcome, such as the identification of cathode materials with high energy density and an electrolyte with a wide electrochemical stability window that can plate and strip calcium metal, before market implementation. Herein, the feasibility and cycling performance of Ca2+ intercalation into a desodiated layered Na2FePO4F host is described. This is the first demonstration of Ca2+ intercalation into a polyanionic framework, which implies that other polyanionic framework materials may be active for Ca2+ intercalation. Although substantial effort is expected in order to develop a high energy density cathode material, this study demonstrates the feasibility of Ca2+ intercalation into multiple host structures types, thereby extending opportunities for development of Ca insertion host structures, suggesting such a cathode material can be identified and developed.

  15. 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.

  16. Identification of the Parameters of Menétrey -Willam Failure Surface of Calcium Silicate Units

    Science.gov (United States)

    Radosław, Jasiński

    2017-10-01

    The identification of parameters of Menétrey-Willamsurface made of concrete, masonry or autoclaved aerated concrete is not complicated. It is much more difficult to identify failure parameters of masonry units with cavities. This paper describes the concept of identifying the parameters of Menétrey-Willam failure surface (M-W-3) with reference to masonry units with vertical cavities. The M-W-3 surface is defined by uniaxial compressive strength fc, uniaxial tensile strength ft and eccentricity of elliptical function e. A test stand was built to identify surface parameters. It was used to test behaviour of masonry units under triaxial stress and conduct tests on whole masonry units in the uniaxial state. Results from tests on tens of silicate masonry units are presented in the Haigh-Westergaard (H-W) space. Statistical analyses were used to identify the shape of surface meridian, and then to determine eccentricity of the elliptical function.

  17. Effects of surface application of dolomitic limestone and calcium-magnesium silicate on soybean and maize in rotation with green manure in a tropical region

    Directory of Open Access Journals (Sweden)

    Gustavo Spadotti Amaral Castro

    2015-01-01

    Full Text Available Although lime is currently the material most frequently used to ameliorate soil acidity in Brazil, silicate could efficiently replace this source because of its greater solubility and its greater silicon content, which are beneficial for plant development. This study aimed to evaluate the effects of superficial lime and silicate application on soil chemical attributes as well as on soybean and maize nutrition and grain yields when these crops are grown in rotation with green manure. The experimental design was a complete randomized block with sixteen replicates. Plots were treated with one of two materials for acidity correction (dolomitic lime and calcium/magnesium silicate or with no soil correction, as a control. Silicate corrected soil acidity and increased exchangeable base levels in soil at greater depths faster than does liming. The application of both acidity-correcting materials increased N, Ca and Mg leaf concentrations, and all yield components and grain yield in soybean; but in maize, just silicate also increased N and Si when compared with lime, whereas both acidity-correcting increased just two yield components: grains per ear and mass of 100 grains, resulting in highest grain yield. The application of both acidity-correcting materials increased dry matter production of green manures, but for pigeon pea the silicate provided the best result in this dry-winter region.

  18. Sodium-calcium exchanger and multiple sodium channel isoforms in intra-epidermal nerve terminals

    Directory of Open Access Journals (Sweden)

    Gasser Andreas

    2010-11-01

    Full Text Available Abstract Background Nociception requires transduction and impulse electrogenesis in nerve fibers which innervate the body surface, including the skin. However, the molecular substrates for transduction and action potential initiation in nociceptors are incompletely understood. In this study, we examined the expression and distribution of Na+/Ca2+ exchanger (NCX and voltage-gated sodium channel isoforms in intra-epidermal free nerve terminals. Results Small diameter DRG neurons exhibited robust NCX2, but not NCX1 or NCX3 immunolabeling, and virtually all PGP 9.5-positive intra-epidermal free nerve terminals displayed NCX2 immunoreactivity. Sodium channel NaV1.1 was not detectable in free nerve endings. In contrast, the majority of nerve terminals displayed detectable levels of expression of NaV1.6, NaV1.7, NaV1.8 and NaV1.9. Sodium channel immunoreactivity in the free nerve endings extended from the dermal boundary to the terminal tip. A similar pattern of NCX and sodium channel immunolabeling was observed in DRG neurons in vitro. Conclusions NCX2, as well as NaV1.6, NaV1.7, NaV1.8 and NaV1.9, are present in most intra-epidermal free nerve endings. The presence of NCX2, together with multiple sodium channel isoforms, in free nerve endings may have important functional implications.

  19. Sodium-calcium exchanger and multiple sodium channel isoforms in intra-epidermal nerve terminals.

    Science.gov (United States)

    Persson, Anna-Karin; Black, Joel A; Gasser, Andreas; Cheng, Xiaoyang; Fischer, Tanya Z; Waxman, Stephen G

    2010-11-30

    Nociception requires transduction and impulse electrogenesis in nerve fibers which innervate the body surface, including the skin. However, the molecular substrates for transduction and action potential initiation in nociceptors are incompletely understood. In this study, we examined the expression and distribution of Na+/Ca2+ exchanger (NCX) and voltage-gated sodium channel isoforms in intra-epidermal free nerve terminals. Small diameter DRG neurons exhibited robust NCX2, but not NCX1 or NCX3 immunolabeling, and virtually all PGP 9.5-positive intra-epidermal free nerve terminals displayed NCX2 immunoreactivity. Sodium channel NaV1.1 was not detectable in free nerve endings. In contrast, the majority of nerve terminals displayed detectable levels of expression of NaV1.6, NaV1.7, NaV1.8 and NaV1.9. Sodium channel immunoreactivity in the free nerve endings extended from the dermal boundary to the terminal tip. A similar pattern of NCX and sodium channel immunolabeling was observed in DRG neurons in vitro. NCX2, as well as NaV1.6, NaV1.7, NaV1.8 and NaV1.9, are present in most intra-epidermal free nerve endings. The presence of NCX2, together with multiple sodium channel isoforms, in free nerve endings may have important functional implications.

  20. Inhibition of late sodium current suppresses calcium-related ventricular arrhythmias by reducing the phosphorylation of CaMK-II and sodium channel expressions

    OpenAIRE

    Xiao-Hong Wei; Shan-Dong Yu; Lu Ren; Si-Hui Huang; Qiao-Mei Yang; Ping Wang; Yan-Peng Chu; Wei Yang; Yan-Sheng Ding; Yong Huo; Lin Wu

    2017-01-01

    Cardiac arrhythmias associated with intracellular calcium inhomeostasis are refractory to antiarrhythmic therapy. We hypothesized that late sodium current (I Na) contributed to the calcium-related arrhythmias. Monophasic action potential duration at 90% completion of repolarization (MAPD90) was significantly increased and ventricular arrhythmias were observed in hearts with increased intracellular calcium concentration ([Ca2+]i) by using Bay K 8644, and the increase became greater in hearts t...

  1. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-01

    Powdered activated carbon (PAC) has traditionally been used by the water treatment industry for the removal of compounds contributing to taste and odor problems. PAC also has the potential to remove naturally occurring organic matter (NOM) from raw waters prior to disinfection, thus controlling the formation of regulated disinfection by-products (DBPs). Many small water systems are currently using PAC for taste and odor control and have the potential to use PAC for controlling DBPs. The Energy & Environmental Research Center has been working on the development of a PAC product to remove NOM from surface water supplies to prevent the formation of carcinogenic DBPs during chlorination. During previous studies, the sodium and calcium content of the lignites showed a significant effect on the sorption capacity of the activated carbon product. As much as a 130% increase in the humic acid sorption capacity of a PAC produced from a high-sodium-content lignite was observed. During this study, activated carbons were prepared from three coals representing high-sodium, low-sodium--low-calcium, and high-calcium compositions in two steps, an initial char formation followed by mild activation with steam to avoid excessive burnout. This set of carbons was characterized with respect to physical and chemical properties. The BET (Brunauer-Emmett-Teller) nitrogen adsorption isotherms gave relatively low surface areas (ranging from 245 to 370 m{sup 2}/g). The lowest-BET area was obtained for the high-sodium carbon, which can be attributed to enlargement of micropores as a result of sodium-catalyzed gasification reaction of the carbon structure. This hypothesis is consistent with the scanning electron microscopy microprobe analyses, which show that in both the coal and the activated carbon from this coal, the sodium is distributed over both the carbon structure and the mineral particles. Thus it is initially associated with carboxylate groups on the coal and then as sodium oxide or

  3. Preparation of the monolith of hierarchical macro-/mesoporous calcium silicate ultrathin nanosheets with low thermal conductivity by means of ambient-pressure drying.

    Science.gov (United States)

    Bai, Jilin; Li, Yuanzhi; Xiang, Jiwei; Ren, Lu; Mao, Mingyang; Zeng, Min; Zhao, Xiujian

    2015-06-01

    Calcium silicate monolith was prepared by the hydrothermal reaction of a slurry of SiO2 , calcium hydroxide, and surfactant (OP-10) obtained by high-energy ball milling, followed by drying at ambient pressure. By using this strategy, the shrinkage due to the collapse of pores during the drying of porous materials, which is a commonly observed phenomena, was successfully avoided. It has a unique microstructure of hierarchical macro-/mesoporous ultrathin calcium silicate nanosheets with a layered gyrolite crystalline structure. Very interestingly, the calcium silicate nanosheets can be peeled off to give a single-layer nanosheet (1.23 nm) of gyrolite by ultrasonication. The monolith has a low apparent density (0.073 g cm(-3) ) and low thermal conductivity (0.0399 W K(-1)  m(-1) ). The reasons behind why the formation of the unique hierarchical macro-/mesoporous ultrathin nanosheets avoids shrinkage during the hydrothermal reaction and drying, and considerably decreases the thermal conductivity, is discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. The effect of human blood on the setting and surface micro-hardness of calcium silicate cements.

    Science.gov (United States)

    Song, Minju; Yue, Wonyoung; Kim, Soyeon; Kim, Wooksung; Kim, Yaelim; Kim, Jeong-Woong; Kim, Euiseong

    2016-11-01

    The purpose of the present study was to evaluate the effects of human blood on the setting and microhardness of calcium silicate cements. Three types of silicate-based cements were used: ProRoot MTA (PMTA), OrthoMTA (OMTA), and RetroMTA (RMTA). Mixed cement was placed into polyethylene molds with lengths of 2 and 4 mm. After storage for 4 days under three different storage conditions, i.e., saline, saline after 5 min of human blood, and human blood, the polyethylene molds were removed. With the specimens set, the surface microhardness was measured using a Vickers microhardness tester, crystalline structure was analyzed with X-ray diffraction (XRD), and the surface characteristics were examined with scanning electron microscopy (SEM). All specimens of 4 mm in length were set with all materials, and the blood groups exhibited lower microhardnesses than did the saline groups (p blood, the numbers of specimens that set were significantly different across the materials (p blood group exhibited reduced microhardness. XRD showed changes of crystalline structure in the PMTA and OMTA blood group, whereas RMTA did not. SEM analysis revealed more rounded and homogeneous structures and demonstrated a clear lack of acicular or needle-like crystals in the PMTA and OMTA blood groups, while RMTA did not reveal substantial differences between the saline- and blood-stored groups. Blood contamination detrimentally affected the surface microhardnesses of all materials; furthermore, among the 2-mm specimens, blood contamination interfered with normal setting. Therefore, RMTA might be a more suitable choice when blood contamination is unavoidable due to limited depth. Clinical relevance RetroMTA might be a more suitable choice in situations in which blood contamination is unavoidable.

  5. 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.

  6. Experimental etch-and-rinse adhesives doped with bioactive calcium silicate-based micro-fillers to generate therapeutic resin-dentin interfaces.

    Science.gov (United States)

    Profeta, A C; Mannocci, F; Foxton, R; Watson, T F; Feitosa, V P; De Carlo, B; Mongiorgi, R; Valdré, G; Sauro, S

    2013-07-01

    This study aimed at evaluating the therapeutic bioactive effects on the bond strength of three experimental bonding agents containing modified Portland cement-based micro-fillers applied to acid-etched dentin and submitted to aging in simulated body fluid solution (SBS). Confocal laser (CLSM) and scanning electron microscopy (SEM) were also performed. A type-I ordinary Portland cement was tailored using different compounds such as sodium-calcium-aluminum-magnesium silicate hydroxide (HOPC), aluminum-magnesium-carbonate hydroxide hydrates (HCPMM) and titanium oxide (HPCTO) to create three bioactive micro-fillers. A resin blend mainly constituted by Bis-GMA, PMDM and HEMA was used as control (RES-Ctr) or mixed with each micro-filler to create three experimental bonding agents: (i) Res-HOPC, (ii) Res-HCPMM and (iii) Res-HPCTO. The bonding agents were applied onto 37% H3PO4-etched dentin and light-cured for 30s. After build-ups, they were prepared for micro-tensile bond strength (μTBS) and tested after 24h or 6 months of SBS storage. SEM analysis was performed after de-bonding, while CLSM was used to evaluate the ultra-morphology/nanoleakage and the mineral deposition at the resin-dentin interface. High μTBS values were achieved in all groups after 24h. Only Res-HOPC and Res-HCPMM showed stable μTBS after SBS storage (6 months). All the resin-dentin interfaces created using the bonding agents containing the bioactive micro-fillers tested in this study showed an evident reduction of nanoleakage and mineral deposition after SBS storage. Resin bonding systems containing specifically tailored Portland cement micro-fillers may promote a therapeutic mineral deposition within the hybrid layer and increase the durability of the resin-dentin bond. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Mechanistic study and modeling of radionuclides retention by the hydrated calcium silicates (HCS) of cements; Etude mecanistique et modelisation de la retention de radionucleides par les silicates de calcium hydrates (CSH) des ciments

    Energy Technology Data Exchange (ETDEWEB)

    Pointeau, I

    2000-09-01

    This work attempts to investigate the modelling of radioisotopes (Cs{sup +}, Pb{sup 2+}, Eu{sup 3+}) immobilization in cement matrix, in the frame of the design of engineered barrier of a deep radwaste repository. The model development concept consists of three major steps: - surface chemistry modelling of the calcium silicate hydrate CSH, used to simulate hydrated cement behaviour; - solid analysis of the batch sorption experiments: identification of the uptake mechanism; - both previous steps are used, with isotherm data, in the modelling of the radioisotopes immobilization in the CSH matrix. Final results: (all modelling are available for all the range of studied Ca/Si ratios and have been validated with predictive calculations). - A thermodynamic modelling of the CSH surface chemistry has been developed. The labile calcium and proton sorption constants on silanol sites (>SiOH) have been extracted. - Cs{sup +} is sorbed on two sites. The silanol site (weak site) has a high site density (10 sites.nm{sup -2}), which accounts for the CSH unsaturation in high [CS{sup +}]. A strong site is also identified. - Pb{sup 2+} immobilization in CSH matrix is modelled with surface equilibria and solubility equilibrium. - Eu{sup 3+} fixation has been investigated with solid analysis: Site-Selective anti Time-Resolved Luminescence Spectroscopy, XPS and SEM-EDS. Eu{sup 3+} thus does not precipitate in CSH water but is sorbed on the CSH surface (high hydroxylated environment). Europium is also (minority site) inserted in the CSH framework. (author)

  8. Reuse of waste foundry sand through interaction with sodium silicate binder; Reutilizacao da areia descartada da fundicao, a partir da sua interacao com agente ligante silicato de sodio

    Energy Technology Data Exchange (ETDEWEB)

    Souza, J.C.; Chinelatto, A.S.A.; Chinelatto, A.L., E-mail: josi3souza@gmail.com [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil); Oliveira, I.L. [Universidade Tecnologica Federal do Parana (UTFPR), Ponta Grossa, PR (Brazil)

    2012-07-01

    Green sand molds are used in metal casting process. However, after heating, activated bentonite present in green sand lose the binding properties, and part of the foundry sand has to be discarded from the process. The ABNT NBR 15.984/2011 establishes the management of waste foundry sand (WFS) avoiding disposal in landfills. The objective of this work was to investigate the possibility of reusing the WFS from the study of their interaction with sodium silicate binder. Studies with silica sand and new green sand was performed to compare the results obtained with the WFS. The characterizations of the samples were performed by measures the compressive strength, X-ray diffraction, optical microscopy and scanning electron microscopy. The results showed that there is interaction of the sodium silicate with the WFS as well as with the silica sand and green sand. (author)

  9. Collapse of sodium polyacrylate chains in calcium salt solutions

    Science.gov (United States)

    Schweins, R.; Huber, K.

    The sodium salt of polyacrylic acid (NaPA) precipitates in the presence of Ca^{2+}-ions. This phase behaviour can be represented by a phase diagram where the critical NaPA concentration is plotted versus the critical Ca^{2+} concentration resulting in a straight line as a phase boundary. The location of this phase boundary is influenced by the presence of an inert monovalent salt like NaCl. The present contribution focuses on the coil dimensions of NaPA chains in dilute aqueous solution corresponding to the one phase region of such a phase diagram. A variety of parameters with which the size and shape of the polyelectrolyte chains can be modulated are revealed. Approaching the phase boundary by decreasing the NaPA concentration at a constant Ca^{2+} content leads to a collapse of the NaPA chains. Combined static and dynamic light scattering suggests a compact spherical shape as the final state of this transition, both in 0.1 M NaCl and in 0.01 M NaCl. In the lower NaCl concentration, indication is presented for the existence of a cigar or pearl necklace like intermediate. Most strikingly, the collapsed chains can be reexpanded by increasing the concentration of inert NaCl at constant content of NaPA and Ca^{2+}. Clearly, excessive Na+-ions displace the Ca^{2+}-ions from the NaPA chains.

  10. Preparation and physicochemical properties of surfactant-free emulsions using electrolytic-reduction ion water containing lithium magnesium sodium silicate.

    Science.gov (United States)

    Okajima, Masahiro; Wada, Yuko; Hosoya, Takashi; Hino, Fumio; Kitahara, Yoshiyasu; Shimokawa, Ken-ichi; Ishii, Fumiyoshi

    2013-04-01

    Surfactant-free emulsions by adding jojoba oil, squalane, olive oil, or glyceryl trioctanoate (medium chain fatty acid triglycerides, MCT) to electrolytic-reduction ion water containing lithium magnesium sodium silicate (GE-100) were prepared, and their physiochemical properties (thixotropy, zeta potential, and mean particle diameter) were evaluated. At an oil concentration of 10%, the zeta potential was ‒22.3 ‒ ‒26.8 mV, showing no marked differences among the emulsions of various types of oil, but the mean particle diameters in the olive oil emulsion (327 nm) and MCT emulsion (295 nm) were smaller than those in the other oil emulsions (452-471 nm). In addition, measurement of the hysteresis loop area of each type of emulsion revealed extremely high thixotropy of the emulsion containing MCT at a low concentration and the olive emulsion. Based on these results, since surfactants and antiseptic agents markedly damage sensitive skin tissue such as that with atopic dermatitis, surfactant- and antiseptic-free emulsions are expected to be new bases for drugs for external use.

  11. X-ray spectra and theoretical elastic properties of crystalline calcium silicate hydrates: comparison with cement hydrated gels

    Directory of Open Access Journals (Sweden)

    Ayuela, A.

    2010-09-01

    Full Text Available For 22 crystalline Calcium Silicates Hydrates, we have calculated their structure and their elastic properties by atomistic force field methods as well as simulate their Xray diffraction patterns. From the computed Young moduli, it can be suggested that the key parameters to determine the elastic properties of crystalline Calcium Silicate Hydrates are densities and water content. We have compared these trends with those of cementitious C-S-H gel and synthetic C-S-H type I as a function of their C/S ratios and nominal water content. Our comparison show that the experimentally suggested values of density and Young moduli for C-S-H gel lie in the range of the calculated CSH crystals. However, we conclude that a detailed correspondence might require investigating structurally within CSH gels the role of water and especially of Ca and Si sites through their C/S ratio.

    En este trabajo se han calculado para 22 Silicatos Cálcicos Hidratados cristalinos, su estructura y sus propiedades elásticas mediante métodos atomísticos “force field”, así como simulado sus espectros de difracción de rayos X. De los módulos de Young calculados se puede deducir, que los parámetros clave que determinan las propiedades elásticas de los Silicatos Cálcicos Hidratados cristalinos son la densidad y el contenido en agua. Nuestros resultados muestran que los valores experimentales de la densidad y de los módulos de Young para el gel C-S-H están dentro del rango de los cristales de CSH calculados. Sin embargo, podemos concluir que para establecer una correlación más directa sería necesario investigar el papel que juegan el agua y sobre todo el Ca y Si, mediante la relación C/S, en la estructura del gel CSH.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-15

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

  13. Polylactic acid-based porous scaffolds doped with calcium silicate and dicalcium phosphate dihydrate designed for biomedical application.

    Science.gov (United States)

    Gandolfi, Maria Giovanna; Zamparini, Fausto; Degli Esposti, Micaela; Chiellini, Federica; Aparicio, Conrado; Fava, Fabio; Fabbri, Paola; Taddei, Paola; Prati, Carlo

    2018-01-01

    Polylactic acid (PLA), dicalcium phosphate dihydrate (DCPD) and/or hydraulic calcium silicate (CaSi) have been used to prepare highly-porous scaffolds by thermally induced phase separation technique (TIPS). Three experimental mineral-doped formulations were prepared (PLA-10CaSi, PLA-5CaSi-5DCPD, PLA-10CaSi-10DCPD). Pure PLA scaffolds constituted the control group. Scaffolds were tested for their chemical-physical and biological properties, namely calcium release, alkalinizing activity, surface microchemistry and micromorphology by ESEM, apatite-forming ability by EDX, micro-Raman and IR spectroscopy, thermal properties by differential scanning calorimetry, mechanical properties by quasi-static parallel-plates compression testing, porosity by a standard water-absorption method and direct-contact cytotoxicity. All mineral-doped scaffolds released biologically relevant ions (biointeractive). A B-type carbonated apatite layer (thickness decreasing along the series PLA-10CaSi-10DCPD>PLA-10CaSi>PLA-5CaSi-5DCPD>PLA) was detected on the surface of all the 28d-aged scaffolds. Surface pores of fresh scaffolds ranged from 10 to 20μm in pure PLA to 10-100μm in PLA-10CaSi. An increase in porosity was detected in 28d-aged pure PLA scaffolds (approx. 30% of material loss with decrease of the PLA chain length); differently, in mineral-doped scaffolds, the PLA degradation was balanced by deposition/nucleation of apatite. All scaffolds showed absence of toxicity, in particular PLA-10CaSi-10DCPD. The designed scaffolds are biointeractive (release biologically relevant ions), nucleate apatite, possess high surface and internal open porosity and can be colonized by cells, appearing interesting materials for bone regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. In vitro cytotoxicity of four calcium silicate-based endodontic cements on human monocytes, a colorimetric MTT assay

    Directory of Open Access Journals (Sweden)

    Sedigheh Khedmat

    2014-08-01

    Full Text Available Objectives This study was performed to evaluate the cytotoxicity of four calcium silicate-based endodontic cements at different storage times after mixing. Materials and Methods Capillary tubes were filled with Biodentine (Septodont, Calcium Enriched Mixture (CEM cement, BioniqueDent, Tech Biosealer Endo (Tech Biosealer and ProRoot MTA (Dentsply Tulsa Dental. Empty tubes and tubes containing Dycal were used as negative and positive control groups respectively. Filled capillary tubes were kept in 0.2 mL microtubes and incubated at 37℃. Each material was divided into 3 groups for testing at intervals of 24 hr, 7 day and 28 day after mixing. Human monocytes were isolated from peripheral blood mononuclear cells and cocultered with 24 hr, 7 day and 28 day samples of different materials for 24 and 48 hr. Cell viability was evaluated using an MTT assay. Results In all groups, the viability of monocytes significantly improved with increasing storage time regardless of the incubation time (p < 0.001. After 24 hr of incubation, there was no significant difference between the materials regarding monocyte viability. However, at 48 hr of incubation, ProRoot MTA and Biodentine were less cytotoxic than CEM cement and Biosealer (p < 0.01. Conclusions Biodentine and ProRoot MTA had similar biocompatibility. Mixing ProRoot MTA with PBS in place of distilled water had no effect on its biocompatibility. Biosealer and CEM cement after 48 hr of incubation were significantly more cytotoxic to on monocyte cells compared to ProRoot MTA and Biodentine.

  15. Odontogenic differentiation of human dental pulp cells by calcium silicate materials stimulating via FGFR/ERK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chao-Hsin [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Hung, Chi-Jr; Huang, Tsui-Hsien [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung City, Taiwan (China); Lin, Chi-Chang [Department of Chemical and Materials Engineering, Tunghai University, Taichung City, Taiwan (China); Kao, Chia-Tze [School of Dentistry, Chung Shan Medical University, Taichung City, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung City, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [Department of Chemical and Materials Engineering, Tunghai University, Taichung City, Taiwan (China)

    2014-10-01

    Bone healing needs a complex interaction of growth factors that establishes an environment for efficient bone formation. We examine how calcium silicate (CS) and tricalcium phosphate (β-TCP) cements influence the behavior of human dental pulp cells (hDPCs) through fibroblast growth factor receptor (FGFR) and active MAPK pathways, in particular ERK. The hDPCs are cultured with β-TCP and CS, after which the cells' viability and odontogenic differentiation markers are determined by using PrestoBlue® assay and western blot, respectively. The effect of small interfering RNA (siRNA) transfection targeting FGFR was also evaluated. The results showed that CS promoted cell proliferation and enhances FGFR expression. It was also found that CS increases ERK and p38 activity in hDPCs, and furthermore, raises the expression and secretion of DSP, and DMP-1. Additionally, statistically significant differences (p < 0.05) have been found in the calcium deposition in si-FGFR transfection and ERK inhibitor between CS and β-TCP; these variations indicated that ERK/MAPK signaling is involved in the silicon-induced odontogenic differentiation of hDPCs. The current study shows that CS substrates play a key role in odontoblastic differentiation of hDPCs through FGFR and modulate ERK/MAPK activation. - Highlights: • CS influences the behavior of hDPCs through fibroblast growth factor receptor. • CS increases ERK and p38 activity in hDPCs. • ERK/MAPK signaling is involved in the Si-induced odontogenic differentiation of hDPCs. • Ca staining shows that FGFR regulates hDPC differentiation on CS, but not on β-TCP.

  16. Solubility and apical sealing characteristics of a new calcium silicate-based root canal sealer in comparison to calcium hydroxide-, methacrylate resin- and epoxy resin-based sealers.

    Science.gov (United States)

    Ersahan, Seyda; Aydin, Cumhur

    2013-01-01

    To assess and compare the water sorption, solubility and apical sealing ability of iRoot SP and three other widely used root canal sealers. Solubility was assessed by immersing standardized samples of calcium silicate- (iRoot SP), calcium hydroxide- (Sealapex), methacrylate resin- (EndoREZ) and epoxy resin- (AH Plus) based sealers in distilled water and measuring weight gain and weight loss at 6 h, 24 h and daily for 14 days. Roots of extracted mandibular premolars (n = 80) were prepared with 0.04-taper nickel-titanium rotary files to a final size 40. Roots were then randomly divided into four experimental groups (n = 18) and two control groups (n = 4), root canal sealers were applied and apical leakage was assessed using the fluid filtration method. Data was analyzed using Kruskal Wallis analysis of variance and Mann-Whitney U-tests, with the level of significance set at p ≤ 0.05. EndoREZ exhibited the highest water sorption, followed by iRoot SP, Sealapex and AH Plus. Sealapex exhibited significantly higher solubility than the other sealers, whereas no significant differences in solubility levels were observed between the other three sealers tested. AH Plus exhibited significantly lower microleakage than Sealapex and EndoREZ, whereas no difference in microleakage was found between AH Plus and iRoot SP. In view of the study findings, all tested sealers except Sealapex met the ANSI/ADA's requirements for solubility and no difference was found between AH Plus and iRoot SP in terms of apical sealing ability.

  17. Fluorescent properties of a green- to red-emitting Eu{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor

    Energy Technology Data Exchange (ETDEWEB)

    Kojima, Yoshiyuki, E-mail: ykojima@chem.cst.nihon-u.ac.jp [Department of Materials and Applied Chemistry, Faculty of Science and Engineering, Nihon University, 1-8, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Numazawa, Masaaki; Umegaki, Tetsuo [Department of Materials and Applied Chemistry, Faculty of Science and Engineering, Nihon University, 1-8, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)

    2012-10-15

    A Eu{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor was prepared by heating a Eu{sup 3+}, Tb{sup 3+} codoped calcium silicate hydrate phosphor formed by liquid-phase reaction for 30 min at 900 Degree-Sign C. The excitation peak wavelength of the resulting phosphor was 379 nm and the emission peak wavelengths were at 542 nm, attributed to the {sup 5}D{sub 4}{yields}{sup 7}F{sub 5} transition of Tb{sup 3+}, and at 613 mm, attributed to the {sup 5}D{sub 0}{yields}{sup 7}F{sub 1} transition of Eu{sup 3+}. The intensity ratio of the two peaks could be freely controlled by varying the Eu/Tb atomic ratio of the Eu{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor, allowing light to be emitted over a wide range from green to red. It was clarified that electron transfer from Tb{sup 3+} to Eu{sup 3+} is occurring. - Highlights: Black-Right-Pointing-Pointer A Eu{sup 3+}, Tb{sup 3+} codoped CSH phosphor was synthesized by liquid-phase reaction. Black-Right-Pointing-Pointer CSH phosphor was heated at 900 Degree-Sign C to obtain Eu{sup 3+}, Tb{sup 3+} codoped amorphous calcium silicate phosphor. Black-Right-Pointing-Pointer Under 379 nm excitation, this phosphor showed emission peaks at 542 nm and 613 nm. Black-Right-Pointing-Pointer The luminescent color could be continuously changed from green to red with increasing Eu/Tb atomic ratio. Black-Right-Pointing-Pointer It was clarified that electron transfer from Tb{sup 3+} to Eu{sup 3+} is occurring.

  18. Influence of sodium borate on the early age hydration of calcium sulfoaluminate cement

    Energy Technology Data Exchange (ETDEWEB)

    Champenois, Jean-Baptiste; Dhoury, Mélanie [CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze Cedex (France); Cau Dit Coumes, Céline, E-mail: celine.cau-dit-coumes@cea.fr [CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze Cedex (France); Mercier, Cyrille [LMCPA, Université de Valenciennes et du Hainaut Cambrésis, 59600 Maubeuge (France); Revel, Bertrand [Centre Commun de Mesure RMN, Université Lille1 Sciences Technologies, Cité Scientifique, 59655 Villeneuve d' Ascq Cedex (France); Le Bescop, Patrick [CEA, DEN, DPC, SECR, F-91192 Gif-sur-Yvette (France); Damidot, Denis [Ecole des Mines de Douai, LGCgE-GCE, 59508 Douai (France)

    2015-04-15

    Calcium sulfoaluminate (CSA) cements are potential candidates for the conditioning of radioactive wastes with high sodium borate concentrations. This work thus investigates early age hydration of two CSA cements with different gypsum contents (0 to 20%) as a function of the mixing solution composition (borate and NaOH concentrations). Gypsum plays a key role in controlling the reactivity of cement. When the mixing solution is pure water, increasing the gypsum concentration accelerates cement hydration. However, the reverse is observed when the mixing solution contains sodium borate. Until gypsum exhaustion, the pore solution pH remains constant at ~ 10.8, and a poorly crystallized borate compound (ulexite) precipitates. A correlation is established between this transient precipitation and the hydration delay. Decreasing the gypsum content in the binder, or increasing the sodium content in the mixing solution, are two ways of reducing the stability of ulexite, thus decreasing the hydration delay.

  19. Formation of hydrate films on the surface of calcium silicate and aluminate in the presence of polyelectrolytes

    Science.gov (United States)

    Kurochkina, G. N.

    2017-08-01

    To elucidate the mechanism of moistening and overmoistening of soils and mineral soil components capable of chemical hydration, the sorption of water vapor has been studied in combination with synchronous conductometric measurements. Effect of organic polyelectrolyte molecules on the hydration kinetics and the formation of hydrate films on their surface has been revealed for dehydrated calcium silicate and aluminate simulating minor soil components. The plotting of sorption-desorption curves has shown that hydrate-polymer films formed by aliphatic or aromatic polyelectrolytes with different functional groups (-COOH,-OH,-NH2,-CONH, etc.) significantly vary in dispersion and structure. The changes in dispersion during hydration are frequently not correlated with the amount of resulting hydrates, the content of which is controlled by the crystallochemical features of sorbents, the structure and activity of the polymer functional groups, and the conditions of sorption kinetic studies. It has been shown that the formation of low-permeable surface organomineral layers is typical for aliphatic polyelectrolytes, while more permeable layers determining the water-physical and structure-forming properties of soils are typical for aromatic polyelectrolytes.

  20. Biological Assessment of a Calcium Silicate Incorporated Hydroxyapatite-Gelatin Nanocomposite: A Comparison to Decellularized Bone Matrix

    Directory of Open Access Journals (Sweden)

    Dong Joon Lee

    2014-01-01

    Full Text Available Our laboratory utilized biomimicry to develop a synthetic bone scaffold based on hydroxyapatite-gelatin-calcium silicate (HGCS. Here, we evaluated the potential of HGCS scaffold in bone formation in vivo using the rat calvarial critical-sized defect (CSD. Twelve Sprague-Dawley rats were randomized to four groups: control (defect only, decellularized bone matrix (DECBM, and HGCS with and without multipotent adult progenitor cells (MAPCs. DECBM was prepared by removing all the cells using SDS and NH4OH. After 12 weeks, the CSD specimens were harvested to evaluate radiographical, histological, and histomorphometrical outcomes. The in vitro osteogenic effects of the materials were studied by focal adhesion, MTS, and alizarin red. Micro-CT analysis indicated that the DECBM and the HGCS scaffold groups developed greater radiopaque areas than the other groups. Bone regeneration, assessed using histological analysis and fluorochrome labeling, was the highest in the HGCS scaffold seeded with MAPCs. The DECBM group showed limited osteoinductivity, causing a gap between the implant and host tissue. The group grafted with HGCS+MAPCs resulting in twice as much new bone formation seems to indicate a role for effective bone regeneration. In conclusion, the novel HGCS scaffold could improve bone regeneration and is a promising carrier for stem cell-mediated bone regeneration.

  1. Push-Out Bond Strength and Surface Microhardness of Calcium Silicate-Based Biomaterials: An in vitro Study.

    Science.gov (United States)

    Majeed, Abdul; AlShwaimi, Emad

    2017-01-01

    This was an in vitro evaluation of push-out bond strength and surface microhardness of calcium silicate-based biomaterials in coronal and apical root dentin. Ninety sections (2 mm thick) of coronal and apical root dentin were obtained from roots of 60 extracted teeth; the canals were enlarged to a standardized cavity diameter of 1.3 mm. Sections were randomly divided into 6 groups (n = 15 per group), and cavities were filled with Biodentine™, BioAggregate, or ProRoot mineral trioxide aggregate (MTA), according to the manufacturers' instructions. Push-out bond strength values were measured using a universal testing machine under a compressive load at a speed of 1 mm/min. Samples were analyzed under a light microscope to determine the nature of bond failure. Ten samples (2 mm thick) were prepared for all the materials, and Vickers microhardness was determined using a digital hardness tester. Data were analyzed using one-way analysis of variance and Tukey-Kramer multiple comparison tests at a significance level of p microhardness and BioAggregate (68.79 HV) showed the lowest hardness. Biodentine and ProRoot MTA showed higher bond strength and microhardness compared to BioAggregate. © 2016 S. Karger AG, Basel.

  2. Swelling behavior of ion exchange resins incorporated in tri-calcium silicate cement matrix: II. Mechanical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Neji, M., E-mail: mejdi.neji@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Polytech Lille, LML UMR, 8107 Villeneuve d' Ascq (France); Bary, B.; Le Bescop, P. [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Burlion, N. [Polytech Lille, LML UMR, 8107 Villeneuve d' Ascq (France)

    2015-12-15

    This paper presents the second part of a study aiming at modelling the mechanical behavior of composites made up of ion exchange resins (IER) solidified in a tri-calcium silicate cement paste (C{sub 3}S). Such composites may be subjected to internal pressures due to ion exchange processes between ionic species which are in IER and interstitial solution of the cement paste. The reactive transport model developed in the companion paper is coupled in this study to a multi-scale approach describing the mechanical behavior of the material. It is based on an analogy with thermomechanics for taking in account the IER internal pressures, and on Eshelby-based homogenization techniques to estimate both mechanical and coupling parameters. A laboratory test has been set up to measure the macroscopic strain caused by the swelling phenomenon. The model has been finally implemented in a finite elements software. The simulation of the laboratory tests has been performed and the results have been analyzed and compared to experimental data. - Highlights: • Experimental analysis about mechanical behavior of a composite material. • Chemo-Mechanical-Transport modeling on a composite material made up with IER embedded into cement paste matrix. • Multi-scale modeling.

  3. Effects of nanosilver and nanozinc incorporated mesoporous calcium-silicate nanoparticles on the mechanical properties of dentin.

    Directory of Open Access Journals (Sweden)

    Jie Zhu

    Full Text Available Mesoporous calcium-silicate nanoparticles (MCSNs are advanced biomaterials for drug delivery and mineralization induction. They can load silver and exhibit significantly antibacterial effects. However, the effects of MCSNs and silver-loaded MCSNs on dentin are unknown. The silver (Ag and/or zinc (Zn incorporated MCSNs (Ag-Zn-MCSNs were prepared by a template method, and their characterizations were tested. Then the nanoparticles were filled into root canals and their effects on the dentin were investigated. Ag-Zn-MCSNs showed characteristics of mesoporous materials and sustained release of ions over time. Ag-Zn-MCSNs adhered well to the root canal walls and infiltrated into the dentinal tubules after ultrasound activation. Ag-Zn-MCSNs showed no significantly negative effects on either the flexural strength or the modulus of elasticity of dentin, while CH decreased the flexural strength of dentin significantly (P<0.05. These findings suggested that Ag and Zn can be incorporated into MCSNs using a template method, and the Ag-Zn-MCSNs may be developed into a new disinfectant for the root canal and dentinal tubules.

  4. Swelling behavior of ion exchange resins incorporated in tri-calcium silicate cement matrix: I. Chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Neji, M., E-mail: mejdi.neji@cea.fr [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Polytech Lille – LML UMR, 8107 Villeneuve d' Ascq (France); Bary, B.; Le Bescop, P. [CEA, DEN, DPC, SECR, Laboratoire d' Etude du Comportement des Bétons et des Argiles, F-91191 Gif-sur-Yvette (France); Burlion, N. [Polytech Lille – LML UMR, 8107 Villeneuve d' Ascq (France)

    2015-12-15

    This paper presents the first part of a theoretical and experimental work aiming at modeling the chemo-mechanical behavior of composites made up of ion exchange resins (IER) solidified in a tri-calcium silicate cement paste (C{sub 3}S). Because of ion exchange processes, the volume change of the IER may cause internal pressures leading to the degradation of the material. In this study, a predictive modeling is developed for describing the chemical behavior of such material. It is based on thermodynamic equilibria to determine the evolution of the ion exchange processes, and the potential precipitation of portlandite in the composite. In parallel, a phenomenological study has been set up to understand chemical phenomena related to the swelling mechanisms. The model created has been finally implemented in a finite elements software; the simulation of a laboratory test has been performed and the results compared to experimental data. - Highlights: • Ion exchange theory to model the swelling behavior of Ion exchange resin. • Experimental phenomenon analysis about Chemo-mechanical interaction between IER and cement paste matrix. • Chemo-Transport modeling on a composite material made with IER embedded into cement paste matrix.

  5. Synthesis and Enhanced Phosphate Recovery Property of Porous Calcium Silicate Hydrate Using Polyethyleneglycol as Pore-Generation Agent

    Directory of Open Access Journals (Sweden)

    Ling Pei

    2013-07-01

    Full Text Available The primary objective of this paper was to synthesize a porous calcium silicate hydrate (CSH with enhanced phosphate recovery property using polyethyleneglycol (PEG as pore-generation agent. The formation mechanism of porous CSH was proposed. PEG molecules were inserted into the void region of oxygen–silicon tetrahedron chains and the layers of CSH. A steric hindrance layer was generated to prevent the aggregation of solid particles. A porous structure was formed due to the residual space caused by the removal of PEG through incineration. This porous CSH exhibited highly enhanced solubility of Ca2+ and OH− due to the decreased particle size, declined crystalline, and increased specific surface area (SBET and pore volume. Supersaturation was increased in the wastewater with the enhanced solubility, which was beneficial to the formation of hydroxyapatite (HAP crystallization. Thus, phosphate can be recovered from wastewater by producing HAP using porous CSH as crystal seed. In addition, the regenerated phosphate-containing products (HAP can be reused to achieve sustainable utilization of phosphate. The present research could provide an effective approach for the synthesis of porous CSH and the enhancement of phosphate recovery properties for environmental applications.

  6. Effect of chemical environment on the dynamics of water confined in calcium silicate minerals: natural and synthetic tobermorite.

    Science.gov (United States)

    Monasterio, Manuel; Gaitero, Juan J; Manzano, Hegoi; Dolado, Jorge S; Cerveny, Silvina

    2015-05-05

    Confined water in the slit mesopores of the mineral tobermorite provides an excellent model system for analyzing the dynamic properties of water confined in cement-like materials. In this work, we use broadband dielectric spectroscopy (BDS) to analyze the dynamic of water entrapped in this crystalline material. Two samples, one natural and one synthetic, were analyzed, and despite their similar structure, the motion of confined water in their zeolitic cavity displays considerably different behavior. The water dynamics splits into two different behaviors depending on the chemical nature of the otherwise identical structural environment: water molecules located in areas where the primary building units are SiO4 relax slowly compared to water molecules located in cavities built with both AlO4 and SiO4. Compared to water confined in regular porous systems, water restricted in tobermorite is slower, indicating that the mesopore structure induces high disorder in the water structure. A comparison with water confined in the C-S-H gel is also discussed in this work. The strong dynamical changes in water due to the presence of aluminum might have important implications in the chemical transport of ions within hydrated calcium silicates, a process that governs the leaching and chemical degradation of cement.

  7. Physicochemical Properties and Volumetric Change of Silicone/Bioactive Glass and Calcium Silicate-based Endodontic Sealers.

    Science.gov (United States)

    Tanomaru-Filho, Mario; Torres, Fernanda Ferrari Esteves; Chávez-Andrade, Gisselle Moraima; de Almeida, Madelise; Navarro, Luciana Guilherme; Steier, Liviu; Guerreiro-Tanomaru, Juliane Maria

    2017-12-01

    This study evaluated setting time (ST), radiopacity, pH, flow, solubility, and volumetric change (VC) of a silicone, gutta-percha, and bioactive glass-based sealer, GuttaFlow Bioseal (GFB), and a calcium silicate-based sealer, TotalFill BC Sealer (TFBC), in comparison with AH Plus. ST and flow were evaluated in accordance with the ISO 6876 Standard. pH was evaluated after different time intervals (1, 3, 7, 14, 21, and 28 days). Radiopacity was evaluated by radiographic analysis in millimeters of aluminum. Solubility was evaluated by means of mass loss (%) after 7 and 30 days of immersion in distilled water. VC was evaluated by micro-computed tomography, by using cavities 3 mm deep and 1 mm in diameter in acrylic resin, filled with the materials. The materials were evaluated after setting and after 7 and 30 days of immersion in distilled water. The data were submitted to analysis of variance and Tukey statistical tests (P physicochemical properties. Micro-computed tomography complements the physicochemical analysis of endodontic sealers. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements

    Directory of Open Access Journals (Sweden)

    Sivaprakash Rajasekharan

    2018-01-01

    Full Text Available Tricalcium silicate cements (TSC are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol, exposed surface area (ESA and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter (n = 6/group. For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4. The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA (p < 0.05 while maximum calcium ion release was dependent on Vol of TSC (p < 0.05. Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution (p < 0.05.

  9. Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements.

    Science.gov (United States)

    Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

    2018-01-13

    Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter ( n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA ( p < 0.05) while maximum calcium ion release was dependent on Vol of TSC ( p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution ( p < 0.05).

  10. 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.

  11. Multi-technology Investigation of the Atomic Structure of Calcium Silicate Hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Guoqing; Kilcoyne, David A.; Benmore, Chris J.; Monteiro, Paul J.M.

    2015-01-01

    In this study, synthetic C-S-H samples were investigated to reveal the feature at atomic scale. Rietveld refinement was applied to high resolution X-ray scattering data, yielding the lattice constants of the pseudocrystal structure, as well as the crystallinity along three axes. Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra was collected at calcium L3,2-edge. Evolution of calcium coordination symmetry were studied by investigating spectra characteristics. Pair Distribution Function (PDF) study yields the statistics of atom pair distribution. Coordination number of Ca and Si were obtained by integrating Radial distribution function. Atomic model based on dimeric structure were discussed and compared with experimental data. Synthetic C-S-H samples with increasing Ca/Si ratio exhibit pseudo-crystal structure, resembling Dreierketten configuration similar to natural tobermorite structure. Along c-axis, the repeated structure could not survives two layers in case of low Ca/Si ratio (0.70, 1.05). But in high Ca/Si ratio (1.42) case, the crystallinity along c-axis is much bigger. The coordination number of Ca decreases with increasing Ca/Si ratio. Octahedrally coordinated Ca are observed in sample with Ca/Si ratio of 1.42. Various dimeric models are compared with experimental data. In case of Ca/Si ratio of 1.42, SiO4 tetrahedron chain needs to be shortened in linkage, most probably by substituting bridging SiO4 tetrahedron with CaO6 octahedron. These octahedrons in interlayer space act like pins to join two adjacent layer structures together. The crystallinity is thus increased along c-axis, and average coordination number is therefore reduced. In case of Ca/Si 1.05, crystallinity is low along c-axis since, indicating that not too many Ca ions exist in interlayer space to hold two layers together. Instead, negative charge of end oxygen could be balanced by proton. Ca/Si 0.70 has long tetrahedron chain linkage within layer while the linkage between adjacent

  12. Fracture resistance of simulated immature teeth after apexification with calcium silicate-based materials.

    Science.gov (United States)

    Evren, O K; Altunsoy, Mustafa; Tanriver, Mehmet; Capar, Ismail Davut; Kalkan, Abdussamed; Gok, Tuba

    2016-01-01

    To compare the fracture resistance of simulated immature teeth filled with an apical barrier of mineral trioxide aggregate (MTA), Biodentine, and calcium-enriched mixture (CEM). Fifty-two single-rooted human maxillary central incisors were used. For standardization, the teeth were sectioned 6 mm above and 9 mm below the cementoenamel junction to simulate immature apex. Simulations of roots into immature apices were carried out using 1.5 mm diameter drills. The specimens were then randomly divided into three experimental groups (n = 13) and one control group (n = 13). In experimental groups, MTA, Biodentine, and CEM were placed to apical 4 mm of the simulated immature roots. The samples were stored at 37° C and 100% humidity for 1 week. A load was applied on the crown of all teeth at 135° to their long axis until fracture. The data were analyzed using one-way analysis of variance and Tukey post-hoc tests. No statistically significant differences were found among MTA, CEM, and Biodentine (P > 0.05), and these groups demonstrated higher fracture resistance than control group (P resistance of immature teeth.

  13. Vital Pulp Therapy with Calcium-Silicate Cements: Report of Two Cases.

    Science.gov (United States)

    Ashraf, Hengameh; Rahmati, Afsaneh; Amini, Neda

    2017-01-01

    This article describes successful use of calcium-enriched mixture (CEM) cement and Biodentine in apexogenesis treatment in two 8-year-old patients, one with immature permanent molar diagnosed primarily with irreversible pulpitis and the other with partially vital maxillary central incisor. After access cavity preparation, partial pulpotomy in molar and full pulpotomy in central was performed, and the remaining pulps was capped with either Biodentine or CEM cement, in each tooth. The crowns were restored with composite filling material at the following visit. The post-operative radiographic and clinical examinations (approx. average of 16 months) showed that both treated teeth remained functional, with complete root development and apex formation. A calcified bridge was produced underneath the capping material. No further endodontic intervention was necessary. Considering the healing potential of immature vital pulps, the use of CEM cement and Biodentine for apexogenesis might be an applicable choice. These new endodontic biomaterials might be appropriate for vital pulp therapies in an immature tooth. However, further clinical studies with longer follow-up periods are recommended.

  14. Solid solubility of MgO in the calcium silicates of portland clinker. The effect of CaF2

    Directory of Open Access Journals (Sweden)

    Puertas, F.

    1992-03-01

    Full Text Available The solid solubility of MgO in the calcium silicates of portland clinker has been determined by XRD and XDS. The influence that the presence of CaF2 has on said solubility has also been verified. The solid solution limit of MgO in C3S at 1275 ºC lies at about 1.0% wt, where the triclinic form II stabilizes. The presence of CaF2 does not alter the maximum value of the MgO solubilized in that silicate, although there does take place the stabilization of the triclinic polymorph II at lower MgO contents (between 0.3 - 0.6% wt. The maximum amount of solubilized MgO in βC2 at 1.050 ºC lies around 0.5% wt. This value does not change by the presence of CaF2.Se ha determinado por DRX y EDX la solubilidad sólida del MgO en los silicatos cálcicos del clínker portland. Se ha comprobado, así mismo la influencia que sobre dicha solubilidad tiene la presencia de CaF2. El límite de disolución sólida del MgO en el C3S a 1.275º C se sitúa alrededor del 1,0% en peso, estabilizándose la forma triclínica II. La presencia de CaF2 no altera el valor máximo de MgO solubilizado en este silicato, aunque si se produce la estabilización del polimorfo triclínico II a contenidos menores de MgO (entre 0,3 – 0,6% en peso. La cantidad máxima de MgO solubilizado en e/ βC2S a 1.050 ºC se sitúa en torno al 0,5% en peso. Este valor no se ve modificado por la presencia de CaF2.

  15. 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

    2017-01-01

    . The supersaturated solutions had a pH around 4.7, and calcium binding to hydrogencitrate as the dominant citrate species during precipitation was found to be exothermic with a determined association constant of 357 L mol-1 at 25 °C for unit ionic strength, and δH° = -22 ± 2 kJ mol-1, δS° = -26 ± 8 J K-1 mol-1...

  16. Porous bioceramic bead prepared by calcium phosphate with sodium alginate gel and PE powder

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Y.C. [Department of Orthopaedic Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Ho, M.L.; Wu, S.C. [Department of Physiology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Hsieh, H.S. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Wang, C.K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2008-08-01

    The porous calcium phosphate beads were made by an alginate-interacting Ca ions mechanism on addition of a pore-forming polyethylene (PE) powder at 1250 deg. C sintering. The nature of the powders and porous beads were analyzed through X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and heavy metal analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The porous beads size and the pore microstructure characteristics were determined using scanning electron microscopy (SEM). Beside, the porosity analysis was evaluated out using an Archimedes' principle and mercury porosimetry. Then, the sodium ampicillin was penetrated/adsorbed onto calcium-deficient hydroxyapatite porous beads, and was subsequently released in PBS. No matter whether the raw material was HAp, TCP or biphase, the Ca{sub 9}(HPO{sub 4})(PO{sub 4}){sub 5}OH phase (CDHA) was formed only after sintering. Porous beads of various calcium phosphates with different sizes (0.9-1.1 mm) and pore size groups (60-120 {mu}m and lower than 10 {mu}m) were appeared. The release kinetics of sodium ampicillin from these porous beads have indicated the possibility of using these materials as possible carriers for drug delivery.

  17. The synergistic effects of CO2 laser treatment with calcium silicate cement of antibacterial, osteogenesis and cementogenesis efficacy

    Science.gov (United States)

    Hsu, T.-T.; Kao, C.-T.; Chen, Y.-W.; Huang, T.-H.; Yang, J.-J.; Shie, M.-Y.

    2015-05-01

    Calcium silicate-based material (CS) has been successfully used in dental clinical applications. Some researches show that the antibacterial effects of CO2 laser irradiation are highly efficient when bacteria are embedded in biofilm, due to a photo-thermal mechanism. The purpose of this study was to confirm the effects of CO2 laser irradiation on CS, with regard to both material characterization and human periodontal ligament cell (hPDLs) viability. CS was irradiated with a dental CO2 laser using directly mounted fiber optics in wound healing mode with a spot area of 0.25 cm2, and then stored in an incubator at 100% relative humidity and 37 °C for 1 d to set. The hPDLs cultured on CS were analyzed, along with their proliferation and odontogenic differentiation behaviors. The results indicate that the CO2 laser irradiation increased the amount of Ca and Si ions released from the CS, and regulated cell behavior. CO2 laser-irradiated CS promoted cementogenic differentiation of hPDLs, with the increased formation of mineralized nodules on the substrate’s surface. It also up-regulated the protein expression of multiple markers of cementogenic and the expression of cementum attachment protein. The current study provides new and important data about the effects of CO2 laser irradiation on CS. Taking cell functions into account, the Si concentration released from CS with laser irradiated may be lower than a critical value, and this information could lead to the development of new regenerative therapies for dentin and periodontal tissue.

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

    Directory of Open Access Journals (Sweden)

    Carroll Susan A

    2009-01-01

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

  19. Histological evaluation of tissue reactions to newly synthetized calcium silicate- and hydroxyapatite-based bioactive materials: in vivo study

    Directory of Open Access Journals (Sweden)

    Opačić-Galić Vanja

    2017-01-01

    Full Text Available Introduction/Objective. Development of materials which could be used as biological bone substitutes is one of the most valuable and active fields of biomaterial research. The goal of the study was to research the reaction of tissue on calcium silicate- (CS and hydroxyapatitebased (CS-HA newly synthesized nanomaterials, after being implanted into the subcutaneous tissue of a rats and direct pulp capping of rabbit teeth. Methods. The tested materials were implanted in 40 Wistar male rats, sacrificed after seven, 15, 30, and 60 days. The direct pulp capping was performed on the teeth of rabbits. Cavities were prepared on the vestibular surface of the incisors. The animals were sacrificed after 10 and 15 days. The control material was mineral trioxide aggregate (MTA. Histological analysis covered the tracking of inflammatory reaction cellular components, presence of gigantic cells, and necrosis of the tissue. Results. Seven days after the implantation, the strongest inflammatory response was given by the MTA (3.3 Ѓ} 0.48, while CS and CS-HA scored 3 ± 0.71. After 60 days, the rate of inflammatory reactions dropped, which was the least visible with CS-HA (0.2 ± 0.45. The least visible inflammatory reaction of the rabbits’ pulp tissue was spotted with the CS (1.83 ± 0.75, than with the MTA and CS-HA (2.67 ± 1.53, 3 ± 0.63. Conclusion. The newly synthesized materials caused a slight reaction of the subcutaneous tissue. CS-HA showed the best tissue tolerance. Nanostructural biomaterials caused a slight to moderate inflammatory reaction of the rabbits’ pulp tissue only in the immediate vicinity of the implanted material.

  20. Anticorrosive effects and in vitro cytocompatibility of calcium silicate/zinc-doped hydroxyapatite composite coatings on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yong, E-mail: xfpang@aliyun.com [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zhang, Honglei [College of Chemistry Environmental Science, Hebei University, Baoding 071000 (China); Qiao, Haixia; Nian, Xiaofeng [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Zhang, Xuejiao, E-mail: 527238610@qq.com [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Wang, Wendong; Zhang, Xiaoyun; Chang, Xiaotong [College of Lab Medicine, Hebei North University, Zhangjiakou 075000 (China); Han, Shuguang [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); Pang, Xiaofeng [Institute of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054 (China); International Centre for Materials Physics, Chinese Academy of Science, Shenyang 110015 (China)

    2015-12-01

    Highlights: • We developed a ZnHA/CS-coated Ti implant by using an ED method. • The obtained ZnHA/CS coatings presented a net-like micro-porous. • The ZnHA/CS coating possessed an excellent corrosion protection ability. • The composite coated CP-Ti possesses favourable cytocompatibility. - Abstract: This work elucidated the corrosion resistance and cytocompatibility of electroplated Zn- and Si-containing bioactive calcium silicate/zinc-doped hydroxyapatite (ZnHA/CS) ceramic coatings on commercially pure titanium (CP-Ti). The formation of ZnHA/CS coating was investigated through Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive X-ray and inductively coupled plasma analyses. The XRD image showed that the reaction layer was mainly composed of HA and CaSiO{sub 3}. The fabricated ZnHA/CS coatings presented a porous structure and appropriate thickness for possible applications in orthopaedic surgery. Potentiodynamic polarization tests showed that ZnHA/CS coatings exhibited higher corrosion resistance than CP-Ti. Dissolution tests on the coating also revealed that Si{sup 4+} and Zn{sup 2+} were leached at low levels. Moreover, MC3T3-E1 cells cultured on ZnHA/CS featured improved cell morphology, adhesion, spreading, proliferation and expression of alkaline phosphatase than those cultured on HA. The high cytocompatibility of ZnHA/CS could be mainly attributed to the combination of micro-porous surface effects and ion release (Zn{sup 2+} and Si{sup 4+}). All these results indicate that ZnHA/CS composite-coated CP-Ti may be a potential material for orthopaedic applications.

  1. Synergistic acceleration in the osteogenic and angiogenic differentiation of human mesenchymal stem cells by calcium silicate-graphene composites.

    Science.gov (United States)

    Shie, Ming-You; Chiang, Wei-Hung; Chen, I-Wen Peter; Liu, Wen-Yi; Chen, Yi-Wen

    2017-04-01

    Recent exciting findings of the biological interactions of graphene materials have shed light on potential biomedical applications of graphene-containing composites. Owing to the superior mechanical properties and low coefficient of thermal expansion, graphene has been widely used in the reinforcement of biocomposites. In the present study, various ratios of graphene (0.25wt%, 0.5wt% and 1.0wt%) were reinforced into calcium silicate (CS) for bone graft application. Results show that the graphene was embedded in the composites homogeneously. Adding 1wt% graphene into CS increased the young's modulus by ~47.1%. The formation of bone-like apatite on a range of composites with graphene weight percentages ranging from 0 to 1 has been investigated in simulated body fluid. The presence of a bone-like apatite layer on the composites surface after immersion in simulated body fluid was considered by scanning electron microscopy. In vitro cytocompatibility of the graphene-contained CS composites was evaluated using human marrow stem cells (hMSCs). The proliferation and alkaline phosphatase, osteopontin and osteocalcin osteogenesis-related protein expression of the hMSCs on the 1wt% graphene-contained specimens showed better results than on the pure CS. In addition, the angiogenesis-related protein (vWF and ang-1) secretion of cells was significantly stimulated when the graphene concentration in the composites was increased. These results suggest that graphene-contained CS bone graft are promising materials for bone tissue engineering applications. Copyright © 2016. Published by Elsevier B.V.

  2. Push-Out Bond Strength and Surface Microhardness of Calcium Silicate-Based Biomaterials: An in vitro Study

    Science.gov (United States)

    Majeed, Abdul; AlShwaimi, Emad

    2017-01-01

    Objective This was an in vitro evaluation of push-out bond strength and surface microhardness of calcium silicate-based biomaterials in coronal and apical root dentin. Materials and Methods Ninety sections (2 mm thick) of coronal and apical root dentin were obtained from roots of 60 extracted teeth; the canals were enlarged to a standardized cavity diameter of 1.3 mm. Sections were randomly divided into 6 groups (n = 15 per group), and cavities were filled with Biodentine™, BioAggregate, or ProRoot mineral trioxide aggregate (MTA), according to the manufacturers' instructions. Push-out bond strength values were measured using a universal testing machine under a compressive load at a speed of 1 mm/min. Samples were analyzed under a light microscope to determine the nature of bond failure. Ten samples (2 mm thick) were prepared for all the materials, and Vickers microhardness was determined using a digital hardness tester. Data were analyzed using one-way analysis of variance and Tukey-Kramer multiple comparison tests at a significance level of p Biodentine (42.02; 39.35 MPa) and ProRoot MTA (21.86; 34.13 MPa) showed significantly higher bond strengths than BioAggregate (6.63; 10.09 MPa) in coronal and apical root dentin, respectively (p Biodentine also differed significantly from ProRoot MTA in coronal dentin. Bond failure was predominantly adhesive in Biodentine and ProRoot MTA, while BioAggregate showed predominantly mixed failure. ProRoot MTA (158.52 HV) showed significantly higher microhardness and BioAggregate (68.79 HV) showed the lowest hardness. Conclusion Biodentine and ProRoot MTA showed higher bond strength and microhardness compared to BioAggregate. PMID:27852076

  3. Effects of calcium sources and soluble silicate on bone metabolism and the related gene expression in mice.

    Science.gov (United States)

    Maehira, Fusako; Miyagi, Ikuko; Eguchi, Yukinori

    2009-05-01

    The effects of five calcium (Ca) sources were compared for bone biochemical and mechanical properties and the related gene expression using mice, from the viewpoint of their soluble silicon (Si) content. Weanling male mice were fed diets containing 1% Ca supplemented with CaCO(3) as the control (CT), coral sand (CS), fossil stony coral (FSC), fish bone (FC) and eggshell (EC) powders, and 50 ppm of Si in the CT diet for 6 mo. The mRNA expressions related to bone remodeling were quantified by real-time polymerase chain reaction. Soluble Si content was 9.83, 7.17, 2.48, 0.29, and 0.20 ppm for the CS, FC, FSC, EC, and Ca-deficient basal diets, respectively. Si, CS, and FSC, in order, significantly increased dry and ash weights, Ca and hydroxyproline contents, and alkaline phosphatase and decreased tartrate-resistant acid phosphatase and urinary excretion of hydroxyproline compared with the CT group. Si significantly increased and FC decreased femoral strength and stiffness. In the mRNA expression related to osteoblastogenesis, Si and CS significantly increased runt-related transcription factor 2. Si, CS, and FSC, in order, significantly decreased and FC and EC increased peroxisome proliferator-activated receptor-gamma. In the mRNA expression related to osteoclastogenesis, Si and CS significantly increased and FC and EC decreased the osteoprotegerin/receptor activator of nuclear factor-kappaB ligand ratio, whereas Si and CS decreased transforming growth factor-beta. The results indicated that soluble silicate and CS, with the highest Si content among Ca sources, improved bone biochemical and mechanical properties through stimulation of gene expression related to osteoblastogenesis and suppression of that related to osteoclastogenesis.

  4. Europium doped di-calcium magnesium di-silicate orange–red emitting phosphor by solid state reaction method

    Directory of Open Access Journals (Sweden)

    Ishwar Prasad Sahu

    2015-07-01

    Full Text Available A new orange–red europium doped di-calcium magnesium di-silicate (Ca2MgSi2O7:Eu3+ phosphor was prepared by the traditional high temperature solid state reaction method. The prepared Ca2MgSi2O7:Eu3+ phosphor was characterized by X-ray diffractometer (XRD, transmission electron microscopy (TEM, field emission scanning electron microscopy (FESEM with energy dispersive x-ray spectroscopy (EDX, fourier transform infrared spectra (FTIR, photoluminescence (PL and decay characteristics. The phase structure of sintered phosphor was akermanite type structure which belongs to the tetragonal crystallography with space group P4¯21m, this structure is a member of the melilite group and forms a layered compound. The chemical composition of the sintered Ca2MgSi2O7:Eu3+ phosphor was confirmed by EDX spectra. The PL spectra indicate that Ca2MgSi2O7:Eu3+ can be excited effectively by near ultraviolet (NUV light and exhibit bright orange–red emission with excellent color stability. The fluorescence lifetime of Ca2MgSi2O7:Eu3+ phosphor was found to be 28.47 ms. CIE color coordinates of Ca2MgSi2O7:Eu3+ phosphor is suitable as orange-red light emitting phosphor with a CIE value of (X = 0.5554, Y = 0.4397. Therefore, it is considered to be a new promising orange–red emitting phosphor for white light emitting diode (LED application.

  5. Using calcium silicate to regulate the physicochemical and biological properties when using β-tricalcium phosphate as bone cement

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Chia-Tze; Huang, Tsui-Hsien [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Chen, Yi-Jyun [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Dental Department, Taichung Hospital, Ministry of Health and Welfare, Taichung City, Taiwan (China); Hung, Chi-Jr [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Lin, Chi-Chang, E-mail: chichang31@gmail.com [Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan (China)

    2014-10-01

    β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Regarding the formation of bone-like apatite, the diametral tensile strength as well as the ion release and weight loss of composites were compared both before and after immersions in simulated body fluid (SBF). In addition, we also examined the behavior of human dental pulp cells (hDPCs) cultured on β-TCP/CS composites. The results show that the apatite deposition ability of the β-TCP/CS composites improves as the CS content is increased. For composites with more than a 60% CS content, the samples become completely covered by a dense bone-like apatite layer. At the end of the immersion period, weight losses of 24%, 32%, 34%, 38%, 41%, and 45% were observed for the composites containing 0%, 20%, 40%, 80%, 80% and 100% β-TCP cements, respectively. In addition, the antibacterial activity of CS/β-TCP composite improves as the CS-content is increased. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 60%, the quantity of cells and osteogenesis protein of hDPCs is stimulated by Si released from the β-TCP/CS composites. The degradation of β-TCP and the osteogenesis of CS give strong reason to believe that these calcium-based composite cements will prove to be effective bone repair materials. - Highlights: • CS improved the physicochemical properties and osteogenic activity of β-TCP. • Higher CS in the composite, the shorter setting time and the higher DTS was found. • With a CS more than 40%, the osteogenesis and angiogenesis proteins were promoted by

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    Monica eKukielka

    2011-02-01

    Full Text Available Aim: Increased sodium/calcium exchanger activity (NCX1, an important regulator of cardiomyocyte cystolic calcium may provoke arrhythmias. Exercise training can decrease NCX1 expression in animals with heart failure improving cytosolic calcium regulation, and could thereby reduce the risk for ventricular fibrillation (VF. Methods: To test this hypothesis, a 2-min coronary occlusion was made during the last min. of exercise in dogs with healed myocardial infarctions; 23 had VF (S, susceptible and 13 did not (R, resistant. The animals were randomly assigned to either 10-wk exercise training (progressively increasing treadmill running (S n = 9; R n = 8 or 10-wk sedentary (S n = 14; R n = 5 groups. At the end of the 10-wk period, the exercise + ischemia test provoked VF in sedentary but not trained susceptible dogs. On a subsequent day, cardiac tissue was harvested and NCX1 protein expression was determined by Western blot. Results: In the sedentary group, NCX1 expression was significantly (ANOVA, P<0.05 higher in susceptible compared to resistant dogs. In contrast, NCX1 levels were similar in the exercise trained resistant and susceptible animals. Conclusion: These data suggest that exercise training can restore a more normal NCX1 level in dogs susceptible to ventricular fibrillation, improving cystolic calcium regulation and could thereby reduce the risk for sudden death following myocardial infarction.

  8. Variable Temperature Infrared Spectroscopy Investigations of Benzoic Acid Desorption from Sodium and Calcium Montmorillonite Clays.

    Science.gov (United States)

    Nickels, Tara M; Ingram, Audrey L; Maraoulaite, Dalia K; White, Robert L

    2015-12-01

    Processes involved in thermal desorption of benzoic acid from sodium and calcium montmorillonite clays are investigated by using variable temperature diffuse reflection Fourier transform infrared spectroscopy (DRIFTS). By monitoring the temperature dependence of infrared absorbance bands while heating samples, subtle changes in molecular vibrations are detected and employed to characterize specific benzoic acid adsorption sites. Abrupt changes in benzoic acid adsorption site properties occur for both clay samples at about 125 °C. Difference spectra absorbance band frequency variations indicate that adsorbed benzoic acid interacts with interlayer cations through water bridges and that these interactions can be disrupted by the presence of organic anions, in particular, benzoate.

  9. 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.

  10. Roles of subthreshold calcium current and sodium current in spontaneous firing of mouse midbrain dopamine neurons.

    Science.gov (United States)

    Puopolo, Michelino; Raviola, Elio; Bean, Bruce P

    2007-01-17

    We used a preparation of acutely dissociated neurons to quantify the ionic currents driving the spontaneous firing of substantia nigra pars compacta neurons, isolated from transgenic mice in which the tyrosine hydroxylase promoter drives expression of human placental alkaline phosphatase (PLAP) on the outer surface of the cell membrane. Dissociated neurons identified by fluorescent antibodies to PLAP showed firing properties similar to those of dopaminergic neurons in brain slice, including rhythmic spontaneous firing of broad action potentials and, in some cells, rhythmic oscillatory activity in the presence of tetrodotoxin (TTX). Spontaneous activity in TTX had broader, smaller spikes than normal pacemaking and was stopped by removal of external calcium. Normal pacemaking was also consistently silenced by replacement of external calcium by cobalt and was slowed by more specific calcium channel blockers. Nimodipine produced a slowing of pacemaking frequency. Pacemaking was also slowed by the P/Q-channel blocker omega-Aga-IVA, but the N-type channel blocker omega-conotoxin GVIA had no effect. In voltage-clamp experiments, using records of pacemaking as command voltage, cobalt-sensitive current and TTX-sensitive current were both sizeable at subthreshold voltages between spikes. Cobalt-sensitive current was consistently larger than TTX-sensitive current at interspike voltages from -70 to -50 mV, with TTX-sensitive current larger at voltages positive to -45 mV. These results support previous evidence for a major role of voltage-dependent calcium channels in driving pacemaking of midbrain dopamine neurons and suggest that multiple calcium channel types contribute to this function. The results also show a significant contribution of subthreshold TTX-sensitive sodium current.

  11. Effect of addition of nano-hydroxyapatite on physico-chemical and antibiofilm properties of calcium silicate cements

    Directory of Open Access Journals (Sweden)

    Juliane Maria GUERREIRO-TANOMARU

    Full Text Available ABSTRACT Objective Mineral Trioxide Aggregate (MTA is a calcium silicate cement composed of Portland cement (PC and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2 and hydroxyapatite nanoparticles (HAn. Material and Methods White MTA (Angelus, Brazil; PC (70%+ZrO2 (30%; PC (60%+ZrO2 (30%+HAn (10%; PC (50%+ZrO2 (30%+HAn (20% were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1 in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. Results There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10% and PC+ZrO2+HAn (20% (p>0.05 and these cements presented higher pH levels than MTA (p<0.05. The highest solubility was observed in PC+ZrO2+HAn (10% and PC+ZrO2+HAn (20% (p<0.05. MTA had the shortest initial setting time (p<0.05. All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05. Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05 after the post-manipulation period of 2 days. Conclusions The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%, the final setting time and

  12. 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(+)/Ca(2+)) exchangers, which include the NCX and NCKX [sodium/calcium-potassium (Na(+)/Ca(2+)-K(+)) exchanger] proteins. During enamel maturation, when crystals expand in thickness, Ca(2+) requirements vastly increase but exactly how Ca(2+) 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 Ca(2+) 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 Ca(2+) 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 Ca(2+) transport during amelogenesis. Copyright © 2012 S. Karger AG, Basel.

  13. Impact of sodium polyacrylate on the amorphous calcium carbonate formation from supersaturated solution.

    Science.gov (United States)

    Liu, J; Pancera, S; Boyko, V; Gummel, J; Nayuk, R; Huber, K

    2012-02-21

    A detailed in situ scattering study has been carried out on the formation of amorphous calcium carbonate (ACC) particles modulated by the presence of small amounts of sodium polyacrylate chains. The work is aiming at an insight into the modulation of ACC formation by means of two polyacrylate samples differing in their molecular weight by a factor of 50. The ACC formation process was initiated by an in situ generation of CO(3)(2-) ions via hydrolysis of 10 mM dimethylcarbonate in the presence of 10 mM CaCl(2). Analysis of the formation process by means of time-resolved small-angle X-ray and light scattering in the absence of any additives provided evidence for a monomer addition mechanism for the growth of ACC particles. ACC formation under these conditions sets in after a lag-period of some 350 s. In the presence of sodium polyacrylate chains, calcium polyacrylate aggregates are formed during the lag-period, succeeded by a modulated ACC growth in a second step. The presence of anionic polyacrylate chains changed the shape of the growing particles toward loose and less homogeneous entities. In the case of low amounts (1.5-7.5 mg/L) of the long chain additive with 97 kDa, the size of the aggregates is comparable to the size of the successively formed hybrid particles. No variation of the lag-period has been observed in this case. Use of the short chain additive with 2 kDa enabled increase of the additive concentration up to 100 mg/L and resulted in a significant increase of the lag-period. This fact, together with the finding that the resulting hybrid particles remained stable in the latter case, identified short chain sodium polyacrylates as more efficient modulators than long chain polyacrylates.

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

    Science.gov (United States)

    Terracciano, C M; Hancox, J C

    2013-10-01

    The sodium-calcium exchanger (NCX) is an electrogenic transporter that is widely expressed in different tissues. In the heart, the NCX plays important roles in calcium ion homeostasis, excitation-contraction coupling and the electrophysiological properties of cardiac myocytes. Precise determination of the roles of the NCX has somewhat been hampered by a lack of selective small molecule inhibitors. In this issue of the BJP, Jost and colleagues present data on a new NCX inhibitor, ORM-10103, which has submicromolar EC50 values against cardiac forward and reverse exchange activity. The compound exhibits improved selectivity over existing small molecule NCX inhibitors and, in particular, appears to be without effect on L-type calcium channels at high concentrations. ORM-10103 could therefore have significant value for studies of the (patho)physiological roles of the NCX in the heart. Further pharmacological studies are required to investigate the actions of ORM-10103 on cardiac cells and tissues and to determine its effects on non-cardiac NCX isoforms. © 2013 The British Pharmacological Society.

  15. Silicate volcanism on Io

    Science.gov (United States)

    Carr, M. H.

    1986-03-01

    This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

  16. Quantitative X-ray pair distribution function analysis of nanocrystalline calcium silicate hydrates: a contribution to the understanding of cement chemistry.

    Science.gov (United States)

    Grangeon, Sylvain; Fernandez-Martinez, Alejandro; Baronnet, Alain; Marty, Nicolas; Poulain, Agnieszka; Elkaïm, Erik; Roosz, Cédric; Gaboreau, Stéphane; Henocq, Pierre; Claret, Francis

    2017-02-01

    The structural evolution of nanocrystalline calcium silicate hydrate (C-S-H) as a function of its calcium to silicon (Ca/Si) ratio has been probed using qualitative and quantitative X-ray atomic pair distribution function analysis of synchrotron X-ray scattering data. Whatever the Ca/Si ratio, the C-S-H structure is similar to that of tobermorite. When the Ca/Si ratio increases from ∼0.6 to ∼1.2, Si wollastonite-like chains progressively depolymerize through preferential omission of Si bridging tetrahedra. When the Ca/Si ratio approaches ∼1.5, nanosheets of portlandite are detected in samples aged for 1 d, while microcrystalline portlandite is detected in samples aged for 1 year. High-resolution transmission electron microscopy imaging shows that the tobermorite-like structure is maintained to Ca/Si > 3.

  17. Extraction of Al and Na from red mud by magnesium oxide sodium ...

    African Journals Online (AJOL)

    AJL

    produce an insoluble dimagnesium silicate, magnesium ferrite, magnesium titanate and a soluble sodium aluminate. A variation of the red mud ... carbonate, reacts with Fe2O3 and forms sodium ferrite as. *Corresponding author. E-mail: Id- ..... Lime Sinter with Calcium: Silica ratio::1, Comalco,. RTS Technical Note: 9392.

  18. Photo-luminescent properties of a green or red emitting Tb{sup 3+} or Eu{sup 3+} doped calcium magnesium silicate phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Onani, Martin O., E-mail: monani@uwc.ca.za [Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Dejene, Francis B. [Department of Physics, University of the Free State, Qwaqwa Campus, Private Bag X13, Phuthaditjhaba 9866 (South Africa)

    2014-04-15

    This study describes green-emitting Tb{sup 3+} or red-emitting Eu{sup 3+} doped calcium magnesium silicate phosphors by ultraviolet excitation at 335 nm. The rare earth activated amorphous calcium silicate was prepared by a solution–combustion process at 600 °C for 5–10 min. The Ca{sub 2}MgSi{sub 2}O{sub 7} prepared using urea and ammonium nitrate has a tetragonal crystal structure. The resulting Tb{sup 3+}-doped phosphor emitted green light centered at 544 nm. The optimum excitation wavelength within the range 300–400 nm was 335 nm. The intensity and emitting wavelength of the Eu{sup 3+} doped samples can be controlled by annealing in a reducing or oxidizing environment, allowing light to be emitted as green or red. When the reducing environment is optimized, the emission spectrum of Ca{sub 2}MgSi{sub 2}O{sub 7}:Eu{sup 2+} is a broad band at 497 nm.

  19. Removal and recovery of phosphate from water by calcium-silicate composites-novel adsorbents made from waste glass and shells.

    Science.gov (United States)

    Jiang, Dan; Amano, Yoshimasa; Machida, Motoi

    2017-03-01

    The removal and recovery of phosphate from water by calcium-silicate composite (CSC) and alkali-treated calcium-silicate composite (ASC) was investigated. ASC had a higher specific surface area and total pore volume, and exhibited better performance of phosphate adsorption than CSC. In the batch mode adsorption studies, the isotherm adsorption experiments data fitted well the Langmuir isotherm model and the maximum adsorption capacities were 120 and 73.0 mg/g for ASC and for CSC, respectively. For the kinetic study, the experimental data fitted very well the pseudo-second-order kinetic model. The uptake of phosphate could be performed well over a wide pH range, from 3.0 to 13.0 for ASC and from 4.0 to 13.0 for CSC. The adsorption of phosphate by ASC was very selective even with 10 times higher concentration of other coexistent anions. For the adsorption of low phosphate concentration (10 mg/L), ASC could efficiently remove phosphate at the dosage of 0.8 g/L, while CSC was even difficult to remove phosphate at the dosage of 4.0 g/L. Phosphate fractionation results and FTIR spectra showed that phosphate-Ca complex was formed through phosphate adsorption process. The adsorbed phosphate could be successfully desorbed by 2% citric acid solution, indicating that the adsorbent after adsorbed phosphate could be reusable as fertilizer in the agricultural field.

  20. 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.

  1. Molecular dynamics simulation of ion sputtering of the solutions of sodium and calcium chlorides

    Science.gov (United States)

    Sirotkin, N. A.; Gurina, D. L.; Titov, V. A.

    2017-11-01

    The ionic sputtering of sodium chloride and calcium chloride solutions was studied by classical molecular dynamics method. It is shown that the ions of the solute transferred into the gas phase both in the form of hydrated ions and in the form of ion pairs in water clusters. The threshold character of the ions transfer process is established. The calculated transfer coefficients of water and anions are in a good agreement with the experimental data. The fraction of water molecules sputtered in the form of clusters increases with the energy inputted in the solution. The fraction of water clusters in the gas phase is 40% at the inputted energy is 45 kJ mol‑1.

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

    Science.gov (United States)

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

    2014-02-05

    Disturbances in myocyte calcium homeostasis are hypothesized to be one cause for cardiac arrhythmia. The full development of this hypothesis requires (i) the identification of all sources of arrhythmogenic calcium and (ii) an understanding of the mechanism(s) through which calcium initiates arrhythmia. To these ends we superfused rat left atria with the late sodium current activator type II Anemonia sulcata toxin (ATXII). This toxin prolonged atrial action potentials, induced early afterdepolarization, and provoked triggered activity. The calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 (N-[2-[[[3-(4-chlorophenyl)-2-propenyl]methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulphon-amide) suppressed ATXII triggered activity but its inactive congener KN-92 (2-[N-(4-methoxy benzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine) did not. Neither drug affected normal atrial contractility. Calcium entry via L-type channels or calcium leakage from sarcoplasmic reticulum stores are not critical for this type of ectopy as neither verapamil ((RS)-2-(3,4-dimethoxyphenyl)-5-{[2-(3,4-dimethoxyphenyl)ethyl]-(methyl)amino}-2-prop-2-ylpentanenitrile) nor ryanodine affected ATXII triggered activity. By contrast, inhibitors of the voltage independent arachidonate-regulated calcium (ARC) channel and the store-operated calcium channel specifically suppressed ATXII triggered activity without normalizing action potentials or affecting atrial contractility. Inhibitors of cytosolic calcium-dependent phospholipase A2 also suppressed triggered activity suggesting that this lipase, which generates free arachidonate, plays a key role in ATXII ectopy. Thus, increased left atrial late sodium current appears to activate atrial Orai-linked ARC and store operated calcium channels, and these voltage-independent channels may be unexpected sources for the arrhythmogenic calcium that underlies triggered activity. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Reporting sodium channel activity using calcium flux: pharmacological promiscuity of cardiac Nav1.5.

    Science.gov (United States)

    Zhang, Hongkang; Zou, Beiyan; Du, Fang; Xu, Kaiping; Li, Min

    2015-02-01

    Voltage-gated sodium (Nav) channels are essential for membrane excitability and represent therapeutic targets for treating human diseases. Recent reports suggest that these channels, e.g., Nav1.3 and Nav1.5, are inhibited by multiple structurally distinctive small molecule drugs. These studies give reason to wonder whether these drugs collectively target a single site or multiple sites in manifesting such pharmacological promiscuity. We thus investigate the pharmacological profile of Nav1.5 through systemic analysis of its sensitivity to diverse compound collections. Here, we report a dual-color fluorescent method that exploits a customized Nav1.5 [calcium permeable Nav channel, subtype 5 (SoCal5)] with engineered-enhanced calcium permeability. SoCal5 retains wild-type (WT) Nav1.5 pharmacological profiles. WT SoCal5 and SoCal5 with the local anesthetics binding site mutated (F1760A) could be expressed in separate cells, each with a different-colored genetically encoded calcium sensor, which allows a simultaneous report of compound activity and site dependence. The pharmacological profile of SoCal5 reveals a hit rate (>50% inhibition) of around 13% at 10 μM, comparable to that of hERG. The channel activity is susceptible to blockage by known drugs and structurally diverse compounds. The broad inhibition profile is highly dependent on the F1760 residue in the inner cavity, which is a residue conserved among all nine subtypes of Nav channels. Both promiscuity and dependence on F1760 seen in Nav1.5 were replicated in Nav1.4. Our evidence of a broad inhibition profile of Nav channels suggests a need to consider off-target effects on Nav channels. The site-dependent promiscuity forms a foundation to better understand Nav channels and compound interactions. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

  4. Preparation and characterization of Na-A zeolite from aluminum scrub and commercial sodium silicate for the removal of Cd2+ from water

    Directory of Open Access Journals (Sweden)

    Mohamed M. Selim

    2017-10-01

    Full Text Available In this work, a low cost preparation scheme of Na-A zeolite from low cost materials was described. Aluminum scrubs were used to prepare sodium aluminate. Commercial sodium silicate and sodium aluminate were then used in the synthesis of zeolite through hydrothermal method under mild conditions. X-ray fluorescence (XRF, X-ray diffraction (XRD and transmission electron microscopy (TEM techniques were employed to confirm the synthesis of pure Na-A zeolite phase. The specific surface area (BET of the prepared zeolite has also been measured. Results indicated that zeolite has relatively high surface area (=374 m2/g. The performance of the prepared zeolite in the removal of Cd2+, a highly toxic heavy metal, from water was investigated. The removal of Cd2+ from water which occurred through precipitation and ion exchange mechanisms was seen to be more efficient comparing to the previous studies. The maximum sorption capacity of Cd2+ was found to be 54.05 meq/100 g according to the Langmuir isotherm model. However, the sorption capacity was found to be 84.09 meq/100 g after 4 repetitions which is attributed to the ease of reaching the Cd2+ ions to the inner pores of zeolite upon using slightly dilute Cd2+ solutions in each repetition.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-12-01

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

  6. Lightweight Heat Resistant Geopolymer-based Materials Synthesized from Red Mud and Rice Husk Ash Using Sodium Silicate Solution as Alkaline Activator

    Directory of Open Access Journals (Sweden)

    Hoc Thang Nguyen

    2017-01-01

    Full Text Available Geopolymer is an inorganic polymer composite with potentials to replace Ordinary Portland Cement (OPC-based materials in the future because of its lower energy consumption, minimal CO2 emissions and lower production cost as it utilizes industrial waste resources. Hence, geopolymerization and the process to produce geopolymers for various applications like building materials can be considered as green industry. Moreover, in our study, the raw materials we used are red mud and rice husk ash, which are are industrial and agricultural wastes that need to be managed to reduce their impact to the environment. The red mud and rice husk ash combined with sodium silicate (water glass solution were mixed to form geopolymer materials. Moreover, the geopolymer specimens were also tested for heat resistance at a temperature of 1000°C for 2 hours. Results suggest high heat resistance with an increase of compressive strength after exposed at high temperature.

  7. Preparation and properties of calcium-silicate filled resins for dental restoration. Part II: Micro-mechanical behaviour to primed mineral-depleted dentine.

    Science.gov (United States)

    Profeta, Andrea Corrado

    2014-11-01

    Evaluating microtensile bond strength (μTBS) and Knoop micro-hardness (KHN) of resin bonded-dentine interfaces created with two methacrylate-based systems either incorporating Bioglass 45S5 (3-E&RA/BG) or MTA (3-E&RA/WMTA). Solvated resins (50% ethanol/50% co-monomers) were used as primers while their neat counterparts were filled with the two calcium-silicate compounds. Application of neat resin adhesive with no filler served as control (3-E&RA). μTBS, KHN analysis and confocal tandem scanning microscopy (TSM) micropermeability were carried out after 24 h and 10 months of storage in phosphate buffer solution (DPBS). Scanning electron microscopy (SEM) was also performed after debonding. High μTBS values were achieved in all groups after 24 h of DPBS storage. On the contrary, solely the specimens created using 3-E&RA/BG and 3-E&RA/WMTA agents showed no significant reduction in terms of μTBS even after 10 months in DPBS; similarly, they did not restore the average superficial micro-hardness to the level of sound dentine, but maintained unchanged KHN values, and no statistical decrease was found following 10 months of DPBS storage. The only statistically significant changes occurred in the resin-dentine interfaces bonded with 3-E&RA that were subjected to a reduction of both μTBS and KHN values with ageing. In terms of micropermeability, adverse results were obtained with 3-E&RA while 3-E&RA/BG and 3-E&RA/WMTA demonstrated a beneficial effect after prolonged DPBS storage. Calcium-silicate filled composite resins performed better than a current etch-and-rinse adhesive and had a therapeutic/protective effect on the micro-mechanical properties of mineral-depleted resin-dentine interfaces. The incorporation of calcium-silicates into dental restorative and bonding agents can create more biomimetic (life-like) restorations. This will not only enable these materials to mimic the physical characteristics of the tooth structure, but will also stabilize and protect the

  8. Influence of saline solution on hydration behavior of β-dicalcium silicate in comparison with biphasic calcium phosphate/hydroxyapatite bio-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Radwan, M.M., E-mail: mmahmoudradwan@yahoo.com [Ceramics Dept, National Research Centre, Cairo (Egypt); Abd El-Hamid, H.K. [Ceramics Dept, National Research Centre, Cairo (Egypt); Mohamed, A.F. [The Holding Company for Production of Vaccines, Sera and Drugs (EGYVAC) (Egypt)

    2015-12-01

    The influence of using saline solution as mixing and curing liquid on some characteristics of β-dicalcium silicate (β-C{sub 2}S) and biphasic compound tri-calcium phosphate/hydroxyapatite (TCP/HAp) bio-ceramics was investigated. β-C{sub 2}S (27–30 nm) was prepared by solid state reaction at 1450 °C, while biphasic compound TCP/HAp (7–15 nm) was synthesized from an aqueous solution of Ca(NO{sub 3}){sub 2}·4H{sub 2}O and (NH{sub 4}){sub 2}HPO{sub 4}·12H{sub 2}O by chemical precipitation method. Setting times, compressive strength, pH values, X-ray diffraction analysis, infrared spectroscopy, scanning electron microscopy (SEM) were investigated. The evaluation of cytotoxicity of both calcium silicate and biphasic compounds to human gingival fibroblasts was carried out. The use of saline solution as mixing and immersing liquid shortened the setting time for the two bio-cements. TCP/HAp did not show any mechanical strength but β-C{sub 2}S showed good strength values. Both synthesized compounds showed a moderate cytotoxicity and both materials were effective in a no significant way. - Highlights: • The dissolution and hydration of β-C{sub 2}S and TCP/HAp in distilled water and saline solution were studied. • TCP/HAp did not show mechanical strength, while β-C{sub 2}S showed good mechanical strength. • The use of saline solution did enhances the dissolution & hydration rate. • An increase in pH values was detected when using saline solution. • Both materials showed a moderate cytotoxicity in no significant way.

  9. Inhibition of late sodium current suppresses calcium-related ventricular arrhythmias by reducing the phosphorylation of CaMK-II and sodium channel expressions.

    Science.gov (United States)

    Wei, Xiao-Hong; Yu, Shan-Dong; Ren, Lu; Huang, Si-Hui; Yang, Qiao-Mei; Wang, Ping; Chu, Yan-Peng; Yang, Wei; Ding, Yan-Sheng; Huo, Yong; Wu, Lin

    2017-04-20

    Cardiac arrhythmias associated with intracellular calcium inhomeostasis are refractory to antiarrhythmic therapy. We hypothesized that late sodium current (I Na) contributed to the calcium-related arrhythmias. Monophasic action potential duration at 90% completion of repolarization (MAPD90) was significantly increased and ventricular arrhythmias were observed in hearts with increased intracellular calcium concentration ([Ca(2+)]i) by using Bay K 8644, and the increase became greater in hearts treated with a combination of ATX-II and Bay K 8644 compared to Bay K 8644 alone. The prolongations caused by Bay K 8644 and frequent episodes of ventricular tachycardias, both in absence and presence of ATX-II, were significantly attenuated or abolished by late I Na inhibitors TTX and eleclazine. In rabbit ventricular myocytes, Bay K 8644 increased I CaL density, calcium transient and myocyte contraction. TTX and eleclazine decreased the amplitude of late I Na, the reverse use dependence of MAPD90 at slower heart rate, and attenuated the increase of intracellular calcium transient and myocyte contraction. TTX diminished the phosphorylation of CaMKII-δ and Nav 1.5 in hearts treated with Bay K 8644 and ATX-II. In conclusion, late I Na contributes to ventricular arrhythmias and its inhibition is plausible to treat arrhythmias in hearts with increased [Ca(2+)]i.

  10. Altervalent substitution of sodium for calcium in biogenic calcite and aragonite

    Science.gov (United States)

    Yoshimura, Toshihiro; Tamenori, Yusuke; Suzuki, Atsushi; Kawahata, Hodaka; Iwasaki, Nozomu; Hasegawa, Hiroshi; Nguyen, Luan T.; Kuroyanagi, Azumi; Yamazaki, Toshitsugu; Kuroda, Junichiro; Ohkouchi, Naohiko

    2017-04-01

    Sodium concentrations in biogenic CaCO3 are several thousands of parts per million, and, on a molar basis, Na is among the most abundant constituent minor element in these carbonates. Nevertheless, the chemical form of Na in CaCO3 is not well constrained. We used synchrotron X-ray spectroscopy to identify the dominant molecular host sites for Na in biogenic calcite and aragonite precipitated by corals, bivalves, and foraminifera. We also used the K-edge X-ray absorption near-edge structure to investigate the chemical environment of Na in biogenic calcium carbonates and identify the altervalent substitution of Na into Ca sites in the lattice structures of calcite and aragonite. Minor cation and anion concentrations in biogenic CaCO3 suggest that the principal substitution mechanism involves charge compensation through the creation of CO32- vacancies. The mostly homogeneous Na concentrations in the skeletal microstructures of the various biota we examined indicate that environmental and biological controls, such as temperature, skeletal microstructure, and calcification rates, have only minor influences on skeletal Na concentrations. A decrease of Na:Ca ratios with increasing age of foraminiferal shells picked from a Quaternary sediment core, indicates progressive release of Na, which suggests that structurally-substituted Na in biogenic CaCO3 is readily leached during burial diagenesis. Whereas the sediment that undergo diagenesis release some Na back to the water column, sodium co-precipitation in biogenic CaCO3 serves as a potential sink of Na for the ocean.

  11. 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

  12. Stochastic spontaneous calcium release events and sodium channelopathies promote ventricular arrhythmias

    Science.gov (United States)

    Campos, Fernando O.; Shiferaw, Yohannes; Vigmond, Edward J.; Plank, Gernot

    2017-09-01

    Premature ventricular complexes (PVCs), the first initiating beats of a variety of cardiac arrhythmias, have been associated with spontaneous calcium release (SCR) events at the cell level. However, the mechanisms underlying the degeneration of such PVCs into arrhythmias are not fully understood. The objective of this study was to investigate the conditions under which SCR-mediated PVCs can lead to ventricular arrhythmias. In particular, we sought to determine whether sodium (Na+) current loss-of-function in the structurally normal ventricles provides a substrate for unidirectional conduction block and reentry initiated by SCR-mediated PVCs. To achieve this goal, a stochastic model of SCR was incorporated into an anatomically accurate compute model of the rabbit ventricles with the His-Purkinje system (HPS). Simulations with reduced Na+ current due to a negative-shift in the steady-state channel inactivation showed that SCR-mediated delayed afterdepolarizations led to PVC formation in the HPS, where the electrotonic load was lower, conduction block, and reentry in the 3D myocardium. Moreover, arrhythmia initiation was only possible when intrinsic electrophysiological heterogeneity in action potential within the ventricles was present. In conclusion, while benign in healthy individuals SCR-mediated PVCs can lead to life-threatening ventricular arrhythmias when combined with Na+ channelopathies.

  13. Molecular Modeling of Ammonium, Calcium, Sulfur, and Sodium Lignosulphonates in Acid and Basic Aqueous Environments

    Science.gov (United States)

    Salazar Valencia, P. J.; Bolívar Marinez, L. E.; Pérez Merchancano, S. T.

    2015-12-01

    Lignosulphonates (LS), also known as lignin sulfonates or sulfite lignin, are lignins in sulfonated forms, obtained from the "sulfite liquors," a residue of the wood pulp extraction process. Their main utility lies in its wide range of properties, they can be used as additives, dispersants, binders, fluxing, binder agents, etc. in fields ranging from food to fertilizer manufacture and even as agents in the preparation of ion exchange membranes. Since they can be manufactured relatively easy and quickly, and that its molecular size can be manipulated to obtain fragments of very low molecular weight, they are used as transport agents in the food industry, cosmetics, pharmaceutical and drug development, and as molecular elements for the treatment of health problems. In this paper, we study the electronic structural and optical characteristics of LS incorporating ammonium, sulfur, calcium, and sodium ions in acidic and basic aqueous media in order to gain a better understanding of their behavior and the very interesting properties exhibit. The studies were performed using the molecular modeling program HyperChem 5 using the semiempirical method PM3 of the NDO Family (neglect of differential overlap), to calculate the structural properties. We calculated the electronic and optical properties using the semiempirical method ZINDO / CI.

  14. Effects of Chlorhexidine and Sodium Hypochlorite on the Setting Time of Calcium-Enriched Mixture Cement.

    Science.gov (United States)

    Frough Reyhani, Mohammad; Ghasemi, Negin; Shakouie, Sahar; Rahimi, Saeed; Salem Milani, Amin; Ranjbar, Babak

    2015-01-01

    The aim of the present study was to evaluate whether adding 2% chlorhexidine (CHX) and 2.6% sodium hypochlorite (NaOCl) to calcium-enriched mixture (CEM) cement would affect its setting time (ST), or not. In this study, the setting time of CEM cement was evaluated in three groups (n=9) as follows: group 1; CEM cement, group 2; CEM cement+2% CHX and group 3; CEM cement+2.6% NaOCl. Then the mean values of ST were calculated and the Kolmogorov-Smirnov test was used to evaluate the normal distribution of data. The Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis. Statistical significance was set at 0.05. The mean ST for groups 1, 2 and 3 were 105, 120 and 220 min, respectively. There was a significant increase in the duration of ST in group 3 (NaOCl) in comparison with the two other groups (Pchlorhexidine did not alter the ST.

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

    OpenAIRE

    Manjanna Kolammanahalli Mallappa; Rajesh Kesarla; Shivakumar Banakar

    2015-01-01

    The aim of the present study was to formulate and investigate the calcium alginate- (CA-) Neusilin US2 nanocomposite microbeads containing preconcentrate of aceclofenac sodium (ACF-Na) liquid microemulsion (L-ME) for enhancement of oral bioavailability. The preconcentrate L-ME is prepared by using Labrafac PG, Labrasol, and Span 80 as oil, surfactant, and cosurfactant, respectively. The solid CA nanocomposite microbeads of L-ME prepared by microemulsification internal gelation technique using...

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

    OpenAIRE

    Lou Ching-Wen; Lee Mong-Chuan; Chen Chih-Kuang; Wen Shih-Peng; Jian Bai-Chen; Lin Jia-Horng

    2016-01-01

    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...

  17. Atributos químicos de solos influenciados pela substituição do carbonato por silicato de cálcio Soil chemical properties influenced by the substitution of calcium carbonate by calcium silicate

    Directory of Open Access Journals (Sweden)

    Renato Ferreira de Souza

    2008-08-01

    ácia do silicato de Ca foi inferior à de carbonato de Ca na melhoria das condições químicas do solo.The application of silicates to soils can result in increased soil cation exchange capacity (CEC, displace anions, especially H2PO4- (diacid phosphate, neutralize the pH and Al toxicity and, in general, increase the nutrient availability to plants. However, calcium silicates may be less efficient than calcium carbonates. To evaluate the effect of calcium carbonate substitution by calcium silicate on the soil chemical properties, especially on phosphorus availability, four experiments were conducted in an entirely randomized design with four replications, in a greenhouse. The treatments consisted of five levels (0, 25, 50, 75, and 100 % of calcium carbonate substitution by calcium silicate, with a 4:1 Ca:Mg stoichiometric and the same amount of CaO, enough to reach a 60 % base saturation. The treatments were applied to 4 dm³ samples of a sandy orthic Quartzarenic Neosol (Quartzpsament, a sandy loam dystrophic Red-Yellow Latosol (Oxisol, sandy clay loam dystrophic Red-Yellow Latosol (Oxisol and a clayey dystrophic Red Latosol (Oxisol; each soil represented one experiment. The pH values in H2O, P, phosphorus in the equilibrium solution (P-rem, K, Ca, Mg, Si, Al, H + Al, organic matter (OM, Cu, Mn, Zn and B, sum of bases (S, effective (t ant total (T CEC, base saturation (V and Al saturation (m were submitted to analysis of variance and simple regression models fitted as a function of CaCO3 substitution by CaSiO3 levels. It was observed that carbonate substitution by silicate promoted significant increases in the values of Si, Al, H + Al and m and reduction in the values of P-rem, pH, S, t and V. The values of Mehlich 1 P, K, Mg, OM, T, Mn, Cu, and B were not influenced significantly. A reduction in Zn availability was verified in the dystrophic orthic Quartzarenic Neosol only. Calcium silicate was less efficient than calcium carbonate in the improvement of soil chemical

  18. Comparative evaluation of a dentifrice containing calcium sodium phosphosilicate to a dentifrice containing potassium nitrate for dentinal hypersensitivity: A clinical study

    National Research Council Canada - National Science Library

    Satyapal, Tanya; Mali, Rohini; Mali, Amita; Patil, Vishakha

    2014-01-01

    .... This study was designed to assess the efficacy of a new toothpaste containing 5% calcium sodium phosphosilicate for the treatment of dentinal hypersensitivity and also compare it with 5% potassium nitrate...

  19. 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 ...

  20. 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.

  1. Calcium

    Science.gov (United States)

    ... Turn to calcium-fortified (or "calcium-set") tofu, soy milk, tempeh, soy yogurt, and cooked soybeans (edamame). Calcium-fortified foods. Look for calcium-fortified orange juice, soy or rice milk, breads, and cereal. Beans. You can get decent ...

  2. The role of integrin αv in proliferation and differentiation of human dental pulp cell response to calcium silicate cement.

    Science.gov (United States)

    Hung, Chi-Jr; Hsu, Hsin-I; Lin, Chi-Chang; Huang, Tsui-Hsien; Wu, Buor-Chang; Kao, Chia-Tze; Shie, Ming-You

    2014-11-01

    It has been proved that integrin αv activity is related to cell proliferation, differentiation, migration, and organ development. However, the biological functions of integrin αv in human dental pulp cells (hDPCs) cultured on silicate-based materials have not been explored. The aim of this study was to investigate the role of integrin αv in the proliferation and odontogenic differentiation of hDPCs cultured with the effect of calcium silicate (CS) cement and β-tricalcium phosphate (TCP) cement. In this study, hDPCs were cultured on CS and TCP materials, and we evaluated fibronectin (FN) secretion and integrin αv expression during the cell attachment stage. After small interfering RNA transfection targeting integrin αv, the proliferation and odontogenesis differentiation behavior of hDPCs were analyzed. The results indicate that CS releases Si ion-increased FN secretion and adsorption, which promote cell attachment more effectively than TCP. The CS cement facilitates FN and αv subintegrin expression. However, the FN adsorption and integrin expression of TCP are similar to that observed in the control dish. Integrin αv small interfering RNA inhibited odontogenic differentiation of hDPCs with the decreased formation of mineralized nodules on CS. It also down-regulated the protein expression of multiple markers of odontogenesis and the expression of dentin sialophosphoprotein protein. These results establish composition-dependent differences in integrin binding and its effectiveness as a mechanism regulating cellular responses to biomaterial surface. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Electron Solvation in Liquid Ammonia: Lithium, Sodium, Magnesium, and Calcium as Electron Sources.

    Science.gov (United States)

    Chaban, Vitaly V; Prezhdo, Oleg V

    2016-03-10

    A free electron in solution, known as a solvated electron, is the smallest possible anion. Alkali and alkaline earth atoms serve as electron donors in solvents that mediate outer-sphere electron transfer. We report herein ab initio molecular dynamics simulations of lithium, sodium, magnesium, and calcium in liquid ammonia at 250 K. By analyzing the electronic properties and the ionic and solvation structures and dynamics, we systematically characterize these metals as electron donors and ammonia molecules as electron acceptors. We show that the solvated metal strongly modifies the properties of its solvation shells and that the observed effect is metal-specific. Specifically, the radius and charge exhibit major impacts. The single solvated electron present in the alkali metal systems is distributed more uniformly among the solvent molecules of each metal's two solvation shells. In contrast, alkaline earth metals favor a less uniform distribution of the electron density. Alkali and alkaline earth atoms are coordinated by four and six NH3 molecules, respectively. The smaller atoms, Li and Mg, are stronger electron donors than Na and Ca. This result is surprising, as smaller atoms in a column of the periodic table have higher ionization potentials. However, it can be explained by stronger electron donor-acceptor interactions between the smaller atoms and the solvent molecules. The structure of the first solvation shell is sharpest for Mg, which has a large charge and a small radius. Solvation is weakest for Na, which has a small charge and a large radius. Weak solvation leads to rapid dynamics, as reflected in the diffusion coefficients of NH3 molecules of the first two solvation shells and the Na atom. The properties of the solvated electrons established in the present study are important for radiation chemistry, synthetic chemistry, condensed-matter charge transfer, and energy sources.

  4. Potassium, calcium, magnesium, and sodium levels in biological samples of hypertensive and nonhypertensive diabetes mellitus patients.

    Science.gov (United States)

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

    2008-09-01

    There is accumulating evidence that the metabolism of several essential elements is altered in diabetes mellitus and that these nutrients might have specific roles in the pathogenesis and progress of this disease. The aim of the present study was to compare the level of essential elements, potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na), in biological samples (whole blood, urine, and scalp hair) of patients who have hypertensive diabetes mellitus type 2 (n = 254) and nonhypertensive diabetes mellitus type 2 (n = 228) with those of nondiabetic as control subjects (n = 182; age range of both genders 45-75). The element concentrations were measured by means of an atomic absorption spectrophotometer after microwave-induced acid digestion. The validity and accuracy was checked by conventional wet acid digestion method and using certified reference materials. The overall recoveries of all elements were found in the range of 99.1-99.9% of certified values. The results of this study showed that the mean values of K, Mg, and Ca were significantly reduced, while Na level were higher in blood and scalp hair samples of hypertensive diabetic (HD) patients and nonhypertensive diabetic (NHD) patients as compared to control subjects of both genders (p diabetic patient was found to be higher, but it was not significant (p = 0.05).The urinary levels of these elements were found to be higher in both HD and NHD patients than in the age-matched healthy controls. These results are consistent with those obtained in other studies, confirming that deficiency and efficiency of some essential trace metals may play a role in the development of diabetes mellitus.

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

    Science.gov (United States)

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

    2012-12-05

    Voltage-gated sodium channels (Na(V)s) underlie the upstroke of the action potential in the excitable tissues of nerve and muscle. After opening, Na(V)s rapidly undergo inactivation, a crucial process through which sodium conductance is negatively regulated. Disruption of inactivation by inherited mutations is an established cause of lethal cardiac arrhythmia, epilepsy, or painful syndromes. Intracellular calcium ions (Ca(2+)) modulate sodium channel inactivation, and multiple players have been suggested in this process, including the cytoplasmic Na(V) C-terminal region including two EF-hands and an IQ motif, the Na(V) domain III-IV linker, and calmodulin. Calmodulin can bind to the IQ domain in both Ca(2+)-bound and Ca(2+)-free conditions, but only to the DIII-IV linker in a Ca(2+)-loaded state. The mechanism of Ca(2+) regulation, and its composite effect(s) on channel gating, has been shrouded in much controversy owing to numerous apparent experimental inconsistencies. Herein, we attempt to summarize these disparate data and propose a novel, to our knowledge, physiological mechanism whereby calcium ions promote sodium current facilitation due to Ca(2+) memory at high-action-potential frequencies where Ca(2+) levels may accumulate. The available data suggest that this phenomenon may be disrupted in diseases where cytoplasmic calcium ion levels are chronically high and where targeted phosphorylation may decouple the Ca(2+) regulatory machinery. Many Na(V) disease mutations associated with electrical dysfunction are located in the Ca(2+)-sensing machinery and misregulation of Ca(2+)-dependent channel modulation is likely to contribute to disease phenotypes. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  6. Effect of calcium hypochlorite and chloramine on blood biochemistry and sodium pentobarbital induced sleeping time in mice.

    Science.gov (United States)

    Ishaq, Sidra; Rasheed, Muhammad Adil; Ashraf, Muhammad; Altaf, Imran; Rehmat, Saima; Fatima, Ghulam

    2016-09-01

    Disinfectants are chemical agents used to eradicate, deactivate or kill microorganisms. Chemical disinfectants especially chlorine compound are extensively used for water sanitization. Among these calcium hypochlorite and chloramines are commonly used now a day. Large number of chemical compounds, drugs and endogenous substances are metabolized by hepatic enzymes known as cytochrome P450 enzyme system. Many chemicals are capable of enzyme induction. Enzyme induction may change the metabolism of other drugs and endogenous substances which may alter the plasma concentration of these chemicals. To evaluate the enzyme inducing ability of calcium hypochlorite and chloramine, sleeping time induced by sodium pentobarbital was noted in mice. Normal saline was taken as negative control. Rifampicin, chloramphenicol and grapefruit juice were taken as positive control group. On completion of dosing after 4 weeks, alteration in sleep induction and recovery times was noted and compared. Histological evaluation of liver was observed. A significant decrease in sleeping time was observed in calcium hypochlorite and chloramine treated groups. Both calcium hypochlorite and chloramine caused a significant change in liver enzymes and in the values of complete blood count. In histological evaluation both caused fat deposition in the hepatocytes. It was concluded from the study that both calcium hypochlorite and chloramine were hepatic microsomal enzyme inducer.

  7. Thermochemistry of Calcium-Magnesium-Aluminum-Silicate (CMAS) and Components of Advanced Thermal and Environmental Barrier Coating Systems

    Science.gov (United States)

    Costa, Gustavo C. C.; Acosta, Waldo A.; Zhu, Dongming; Ghoshal, Anindya

    2017-01-01

    There is increasing interest in the degradation mechanism studies of thermal and environmental barrier coatings (TEBCs) of gas turbines by molten CaO-MgO-Al(exp. 2)O(exp. 3)-SiO(exp. 2) CMAS). CMAS minerals are usually referred as silicon-containing sand dust and volcano ash materials that are carried by the intake air into gas turbines, e.g. in aircraft engines, and their deposits often react at high temperatures (greater than 1200 degrees C) with the engine turbine coating systems and components. The high temperature reactions causes degradation and accelerated failure of the static and rotating components of the turbine engines. We discuss some results of the reactions between the CMAS and Rare-Earth (RE = Y, Yb, Dy, Gd, Nd and Sm) - oxide stabilized ZrO(exp. 2) or HfO(exp. 2) systems, and the stability of the resulting oxides and silicates. Plasma sprayed hollow tube samples (outside diameter = 4.7 mm, wall thickness = 0.76 mm and = 26 mm height) were half filled with CMAS powder, wrapped and sealed with platinum foil, and heat treated at 1310 degrees C for 5h. Samples were characterized by differential scanning calorimetry (DSC), X-ray diffraction, and cross-section electron microscopy analysis and energy dispersive X-ray spectroscopy. It was found that CMAS penetrated the samples at the grain boundaries and dissolved the TEBC materials to form silicate phases containing the rare-earth elements. Furthermore, it was found that apatite crystalline phases were formed in the samples with total rare-earth content higher than 12 mol% in the reaction zone for the ZrO(exp. 2) system. In general, samples with the nominal compositions (30YSZ), HfO(exp. 2)-7Dy(exp. 2)O(exp. 2) and ZrO(exp. 2)-9.5Y(exp. 2)O(exp. 3)-2.25Gd(exp. 2)O(exp. 3)-2.25Yb(exp. 2)O(exp. 3) exhibited lower reactivity or more resistance to CMAS than the other coating compositions of this work.

  8. The Effect of Additive “B” on the Properties of CO2-Hardened Foundry Sands with Hydrated Sodium Silicate

    Directory of Open Access Journals (Sweden)

    Kamińska J.

    2017-09-01

    Full Text Available The results of own studies concerning the application of a new additive to the CO2-hardened sodium water glass foundry sands are presented. The new additive, which is a composition of aqueous solutions of modified polyalcohols, has been designated by the symbol “B” and is used as an agent improving the sand knocking out properties. The scope of studies included various mechanical and technological properties of foundry sand mixtures, such as permeability, friability, life cycle of cores and knocking out properties. Two types of water glass with different values of the silica modulus and density, designated as R145 and R150, were tested. Moulding sands used in the tests were made with the additive “B”. For comparison, a reference sand mixture with water glass but without the additive “B” was also prepared.

  9. Sealing ability of a new calcium silicate based material as a dentin substitute in class II sandwich restorations: An in vitro study

    Directory of Open Access Journals (Sweden)

    Raji Viola Solomon

    2014-01-01

    Full Text Available Background: Class ll sandwich restorations are routinely performed where conventional Glass ionomer cement (GIC or Resin-modified GIC (RMGIC is used as a base or dentin substitute and a light curing composite resin restorative material is used as an enamel substitute. Various authors have evaluated the microleakage of composite resin restorations where glass ionomer cement has been used as a base in class II sandwich restorations, but a literature survey reveals limited studies on the microleakage analysis of similar restorations with biodentine as a dentin substitute, as an alternative to glass ionomer cement. The aim of this study is: To evaluate the marginal sealing efficacy of a new calcium-silicate-based material (Biodentine as a dentin substitute, at the cervical margins, in posterior class II sandwich restorations.To compare and evaluate the microleakage at the biodentine/composite interface with the microleakage at the resin-modified GIC/composite interface, in posterior class II open sandwich restorations. To compare the efficacy between a water-based etch and rinse adhesive (Scotch bond multipurpose and an acetone-based etch and rinse adhesive (Prime and bond NT, when bonding biodentine to the composite. To evaluate the enamel, dentin, and interfacial microleakage at the composite and biodentine/RMGIC interfaces. Materials and Methods: Fifty class II cavities were prepared on the mesial and distal surfaces of 25 extracted human maxillary third molars, which were randomly divided into five groups of ten cavities each: (G1 Biodentine group, (G2 Fuji II LC GIC group, (G3 Biodentine as a base + prime and bond NT + Tetric N-Ceram composite, (G4 Biodentine + scotchbond multi-purpose + Tetric N-Ceram composite, (G5 Fuji II LC as a base + prime and bond NT+ Tetric-N Ceram composite. The samples were then subjected to thermocycling, 2500× (5°C to 55°C, followed by the dye penetration test. Scores are given from 0 to 3 based on the depth of

  10. Mechanism of sodium hydrosulfide modulation of L-type calcium channels in rat colonic smooth muscle cells.

    Science.gov (United States)

    Tang, Qincai; Quan, Xiaojing; Yan, Lin; Ren, Haixia; Chen, Wei; Xia, Hong; Luo, Hesheng

    2018-01-05

    Hydrogen sulfide (H 2 S) can exert different effects on the gastrointestinal tract by modulating ion channels. Previously, we found that H 2 S donor sodium hydrosulfide (NaHS) regulates colonic motility through L-type calcium channels, but the molecular mechanism remains unknown. The present study was designed to investigate possible mechanisms underlying the modulation of L-type calcium channels by NaHS in rat colonic smooth muscle cells. L-type calcium currents in colonic smooth muscle cells were recorded using the whole-cell patch-clamp technique. Spontaneous contractions of mid-colonic smooth muscle strips were measured in an organ bath system and a biological signal acquisition system. NaHS evoked a significant rightward shift in the steady-state activation curve of L-type calcium channels, changed the shape of the current-voltage (I-V) curve, and decreased the peak current density at 0mV, although it significantly increased with higher stimulatory voltage. The sulfhydryl-modifying reagent DL-dithiothreitol (DTT) enhanced the effects of NaHS on L-type calcium channels, while diamide (DM) and reduced L-glutathione (GSH) alleviated the effects of NaHS. Additionally, NaHS inhibited the spontaneous high-amplitude contractions of both longitudinal and circular smooth muscle strips in a dose-dependent manner. The inhibitory effects were reversible. DTT and GSH enhanced the effects of NaHS, while DM attenuated the effects of NaHS. In conclusion, NaHS modulates L-type calcium channels in rat colonic smooth muscle cells and regulates the contractile activity of colonic smooth muscle, potentially by modifying the free sulfhydryl groups of L-type calcium channels. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Improvements in the synthesis of zeolites with low Si/Al ratio from Venezuelan sodium silicate for an environmentally friendly process

    Directory of Open Access Journals (Sweden)

    Adriana Lucía García

    2016-04-01

    Full Text Available LTA and FAU zeolites were successfully synthesized from a Venezuelan sodium silicate solution, by hydrothermal crystallization under autogenous pressure at 100°C, with 2–24h crystallization times. The synthesized materials were characterized by XRD, BET specific surface area and SEM. A series of synthesis tests were performed to study the influence of the molar composition of the starting mixture over zeolites crystallization. The effect of crystallization time for a particular synthesis mixture composition was studied for both zeolites types. The reuse as alkaline medium of the mother liquor separated during filtration, and the effect of the aging before crystallization were additionally studied. The experimental result  are in agreement with the crystallization mechanism proposed for zeolites synthesis in liquid phase. The use of a 2SiO2:Al2O3:6.Na2O:240H2O synthesis mixture composition allows obtaining LTA zeolite within 2h of crystallization. For FAU zeolite, no aging period was needed when starting with a 4SiO2:Al2O3:6.6Na2O:264H2O composition. It was possible to synthesize both zeolites with high purity and crystallinity and with adequate water adsorption properties.

  12. Compositional Evolution of Calcium Silicate Hydrate (C-S-H) Structures by Total X-Ray Scattering

    KAUST Repository

    Soyer-Uzun, Sezen

    2011-12-09

    High-energy X-ray diffraction was employed to study the structural characteristics of a set of C-S-H samples with 0.6 ≤ C/S a;circ 1.75. It has been observed that Si is tetrahedrally coordinated to O for all samples irrespective of chemical composition and the Ca-O coordination number gradually decreases from ∼7 to ∼6 with increasing C/S ratio. This suggests that the C-S-H structure evolves from a tobermorite-like structure into a jennite-like structure as a function of increasing C/S ratio as the interlayer space decreases from ∼1.3 to ∼1 nm. Evolution of these short- and medium-range order structural characteristics in the C-S-H system is associated with the alteration of the Ca-O layers and silicate depolymerization with increasing C/S. © 2011 The American Ceramic Society.

  13. Silicate release from glass for pharmaceutical preparations.

    Science.gov (United States)

    Bohrer, Denise; Bortoluzzi, Fabiana; Nascimento, Paulo Cícero; Carvalho, Leandro Machado; Ramirez, Adrian Gustavo

    2008-05-01

    Glass is made of polymeric silica and other minor components, which are necessary for turning the silica into a material more easily moldable and resistant to temperature changes. Glass containers for pharmaceutical usage are classified according to their resistance to a chemical attack, a test carried out in the presence of water and heat. The test is designed to show the released alkalinity, a variable dependent on the amount of sodium oxide, one of the minor components added to the glass mass. In this work, the release of silica from glass by action of constituents from pharmaceutical formulations was investigated. The study included products used in large volumes and usually stored in glass containers. Solutions of amino acids, electrolytes, glucose, oligoelements and others such as heparin and sodium bicarbonate were individually stored in glass containers and heated at 121 degrees C for 30min, as in the water attack test. The test was also carried out only with water, where the pH varied from 2 to 12. The released silicate was measured either by photometry or atomic absorption spectrometry, depending on the nature of the sample. The results showed that silicate is released during the heating cycle even if the contact is with pure water only. The pH exerts a considerable influence on the release, being that the higher the pH, the higher the silica dissolved. An elevated pH, however, is not the only factor responsible for silica dissolution. While in the solutions of NaCl, KCl, Mg Cl2 and ZnSO4 and in most of the amino acids, the concentration of silicate was as high as in pure water (0.1-1.0mg Si/L). In the solutions of sodium acetate, bicarbonate and gluconate, its concentration was much higher, over 30mg Si/L. These results were confirmed by the analysis of commercial products, where in solutions of amino acids the level of silicate ranged from 0.14 to 0.19mg Si/L. On the other hand, calcium gluconate, sodium bicarbonate and potassium phosphate presented

  14. Comparative evaluation of calcium silicate-based dentin substitute (Biodentine® and calcium hydroxide (pulpdent in the formation of reactive dentin bridge in regenerative pulpotomy of vital primary teeth: Triple blind, randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Navneet Grewal

    2016-01-01

    Full Text Available Background: Considering the biological concerns of calcium hydroxide (CH as a pulpotomy agent, an alternative silicate based dentin substitute i.e. Biodentine (Ca3SiO5 was evaluated clinically and radiographically. Aims: To evaluate the effectiveness of dentin substitute (Biodentine in regenerative pulpotomy of vital primary teeth that would giv a biological base to its use in forming reactive dentin bridge and overcoming the drawbacks of calcium hydroxide. Material and Methods: Randomised clinical trial on 40 bilateral carious primary molars in 20 participant children (aged 5-10 years was carried out by same operator using Ca3SiO5(group-1 and CH (group-2 as vital pulpotomy agents. Blinded clinical and radiographic outcomes were observed at 3, 6 and 12 months interval. Results: Clinical outcomes of both protocols were analysed using Pearson's chi-square test applied at P < 0.05. Descriptive statistics were expressed as mean increase in dentin bridge formation in mms from two reference points in standardized radiographs using paired 't'- test at baseline and 12 months and found to be statistically significant (P < 0.05 in group-1 when compared with group-2. Conclusion: Group-1 revealed statistically favourable regenerative potential along with clinical success compared to group 2 thereby sharing both indications and mode of action with CH, but without its drawbacks of physical and clinical properties.

  15. Comparative evaluation of calcium silicate-based dentin substitute (Biodentine®) and calcium hydroxide (pulpdent) in the formation of reactive dentin bridge in regenerative pulpotomy of vital primary teeth: Triple blind, randomized clinical trial.

    Science.gov (United States)

    Grewal, Navneet; Salhan, Rubica; Kaur, Nirapjeet; Patel, Hemal Bipin

    2016-01-01

    Considering the biological concerns of calcium hydroxide (CH) as a pulpotomy agent, an alternative silicate based dentin substitute i.e. Biodentine (Ca3SiO5) was evaluated clinically and radiographically. To evaluate the effectiveness of dentin substitute (Biodentine) in regenerative pulpotomy of vital primary teeth that would giv a biological base to its use in forming reactive dentin bridge and overcoming the drawbacks of calcium hydroxide. Randomised clinical trial on 40 bilateral carious primary molars in 20 participant children (aged 5-10 years) was carried out by same operator using Ca3SiO5(group-1) and CH (group-2) as vital pulpotomy agents. Blinded clinical and radiographic outcomes were observed at 3, 6 and 12 months interval. Clinical outcomes of both protocols were analysed using Pearson's chi-square test applied at P < 0.05. Descriptive statistics were expressed as mean increase in dentin bridge formation in mms from two reference points in standardized radiographs using paired 't'- test at baseline and 12 months and found to be statistically significant (P < 0.05) in group-1 when compared with group-2. Group-1 revealed statistically favourable regenerative potential along with clinical success compared to group 2 thereby sharing both indications and mode of action with CH, but without its drawbacks of physical and clinical properties.

  16. Comparative evaluation of calcium silicate-based dentin substitute (Biodentine®) and calcium hydroxide (pulpdent) in the formation of reactive dentin bridge in regenerative pulpotomy of vital primary teeth: Triple blind, randomized clinical trial

    Science.gov (United States)

    Grewal, Navneet; Salhan, Rubica; Kaur, Nirapjeet; Patel, Hemal Bipin

    2016-01-01

    Background: Considering the biological concerns of calcium hydroxide (CH) as a pulpotomy agent, an alternative silicate based dentin substitute i.e. Biodentine (Ca3SiO5) was evaluated clinically and radiographically. Aims: To evaluate the effectiveness of dentin substitute (Biodentine) in regenerative pulpotomy of vital primary teeth that would giv a biological base to its use in forming reactive dentin bridge and overcoming the drawbacks of calcium hydroxide. Material and Methods: Randomised clinical trial on 40 bilateral carious primary molars in 20 participant children (aged 5-10 years) was carried out by same operator using Ca3SiO5(group-1) and CH (group-2) as vital pulpotomy agents. Blinded clinical and radiographic outcomes were observed at 3, 6 and 12 months interval. Results: Clinical outcomes of both protocols were analysed using Pearson's chi-square test applied at P < 0.05. Descriptive statistics were expressed as mean increase in dentin bridge formation in mms from two reference points in standardized radiographs using paired ‘t’- test at baseline and 12 months and found to be statistically significant (P < 0.05) in group-1 when compared with group-2. Conclusion: Group-1 revealed statistically favourable regenerative potential along with clinical success compared to group 2 thereby sharing both indications and mode of action with CH, but without its drawbacks of physical and clinical properties. PMID:27994411

  17. Statistical approach for assessing the influence of calcium silicate and HPMC on the formulation of novel alfuzosin hydrochloride mucoadhesive-floating beads as gastroretentive drug delivery systems.

    Science.gov (United States)

    Fahmy, Rania Hassan

    2012-09-01

    Multiparticulate floating drug delivery systems have proven potential as controlled-release gastroretentive drug delivery systems that avoid the "all or none" gastric emptying nature of single-unit floating dosage forms. An objective of the presence investigation was to develop calcium silicate (CaSi)/calcium alginate (Ca-Alg)/hydroxypropyl methylcellulose (HPMC) mucoadhesive-floating beads that provide time- and site-specific drug release of alfuzosin hydrochloride (Alf). Beads were prepared by simultaneous internal and external gelation method utilizing 3(2) factorial design as an experimental design; with two main factors evaluated for their influence on the prepared beads; the concentration of CaSi as floating aid (X (1)) and the percentage of HPMC as viscosity enhancer and mucoadhesive polymer (X (2)), each of them was tested in three levels. Developed formulations were evaluated for yield, entrapment efficiency, particle size, surface topography, and buoyancy. Differential scanning calorimetry, Fourier transform infrared spectroscopy, in vitro drug release, as well as in vitro mucoadhesion using rat stomach mucosal membrane were also conducted. Percentage yield and entrapment efficiency ranged from 57.03% to 78.51% and from 49.78% to 83.26%, respectively. Statistical analysis using ANOVA proved that increasing the concentration of either CaSi or HPMC significantly increased the beads yield. Both CaSi and HPMC concentrations were found to significantly affect Alf release from the beads. Additionally, higher CaSi concentration significantly increased the beads diameter while HPMC concentration showed significant positive effect on the beads mucoadhesive properties. CaSi/Ca-Alg/HPMC beads represent simple floating-mucoadhesive gastroretentive system that could be useful in chronopharmacotherapy of benign prostatic hyperplasia.

  18. Combined effect of magnesia and zirconia on the bioactivity of calcium silicate ceramics at C\\S ratio less than unity.

    Science.gov (United States)

    Ewais, Emad M M; Amin, Amira M M; Ahmed, Yasser M Z; Ashor, Eman A; Hess, Ulrike; Rezwan, Kurosch

    2017-01-01

    This paper describes the effect of magnesia in the presence of zirconia on the bioactivity, microstructure and physico-mechanical properties of calcium silicate composition adjusted at calcia/silica ratio(C/S) of 0.5. A mixture from calcium carbonate and silica was conducted at C/S of 0.5. 20wt.% of magnesia and 5-25wt.% of ZrO2 were added. Each mixture was mixed with ethanol in a planetary ball mill, dried, formed and fired at a temperature of 1325±5°C. Phase composition, FE-SEM, and physico-mechanical properties of the fired specimens were determined and explained. The in vitro bioactivities of these specimens were investigated by analysis of their abilities to form apatite in the simulated body fluid (SBF) for a short time (7days) using SEM-EDS. The findings indicated that the surface of the specimens containing 5 and 15wt.% ZrO2 were completely covered by single and multilayered hydroxyapatite (HA) precipitate typical to "cauliflower" morphology, respectively. The surface of the specimen containing 25wt.% ZrO2 did not cover, but there are some scattered HA precipitate. The differences among the results were rationalized based on the phase composition. Vickers hardness and fracture toughness of the specimens of highly promised bioactivity were 2.32-2.57GPa and 1.80-1.50MPa. m(1/2), respectively. The properties of these specimens are similar to the properties of human cortical bone. Consequently, these composites might be used as bone implant materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Environmental scanning electron microscopy connected with energy dispersive x-ray analysis and Raman techniques to study ProRoot mineral trioxide aggregate and calcium silicate cements in wet conditions and in real time.

    Science.gov (United States)

    Gandolfi, Maria Giovanna; Van Landuyt, Kirsten; Taddei, Paola; Modena, Enrico; Van Meerbeek, Bart; Prati, Carlo

    2010-05-01

    ProRoot mineral trioxide aggregate (MTA) and calcium silicate cements are able to set in a moist environment. The aim of the study was to examine the surface structure and composition of a cement paste under wet conditions and in real time during setting by environmental scanning electron microscopy connected with energy dispersive x-ray analysis (ESEM-EDX) and micro-Raman techniques. White ProRoot MTA and experimental white tetrasilicate cement (wTC) and wTC containing bismuth oxide (wTC-Bi) were studied. Cement disks were analyzed 10 minutes after powder-liquid mixing (freshly prepared samples) and after immersion in Dulbecco phosphate-buffered saline at 37 degrees C for 24 hours (24-hour-aged samples). Freshly prepared wet cements at ESEM-EDX exposed an irregular surface (displaying calcium, silicon, aluminum, chlorine reflexes, and bismuth traces in MTA and wTC-Bi) with needle-like and cubic-hexagonal shaped crystals. Aggregates of spheroidal Ca-P-rich crystals (spherulites) appeared on the surface of 24-hour-aged samples. The starting unhydrated powders displayed the typical Raman bands of Portland cement components: alite, belite, and calcium sulfate (only as anhydrite in MTA and as both anhydrite and gypsum in wTC and wTC-Bi). MTA powder showed higher amount of calcium carbonate and lower quantities of anhydrite and higher crystallinity of the silicate component, leading to a slower hydration reaction. Products/markers of hydration reactions were present on fresh samples; ettringite formed on the surface of all the cements; calcium hydroxide (portlandite) was detected only on the surface of wTC, but no conclusion can be drawn on wTC-Bi and MTA because of the interference of bismuth oxide. Calcium phosphate and calcite/aragonite bands were detected on all 24-hour-aged cements; portlandite was no longer detected on wTC. ESEM and micro-Raman are powerful and suitable techniques to investigate endodontic calcium silicate hydrated cements in real time and in

  20. Evaluation of cytocompatibility of calcium silicate-based endodontic sealers and their effects on the biological responses of mesenchymal dental stem cells.

    Science.gov (United States)

    Rodríguez-Lozano, F J; García-Bernal, D; Oñate-Sánchez, R E; Ortolani-Seltenerich, P S; Forner, L; Moraleda, J M

    2017-01-01

    To investigate in vitro the cytocompatibility of the calcium silicate-containing endodontic sealers MTA Fillapex and TotalFill BC Sealer on human periodontal ligament stem cells (hPDLSCs) by assaying their biological responses and compare them with that observed when using an epoxy resin-based sealer (AH Plus). Specimens from the three different endodontic sealers were eluated with culture medium for 24 h. The cytotoxicity of these eluates was evaluated using the MTT assay. In addition, an in vitro scratch wound healing model was used to determine their effects on cell migration. Cell adhesion to collagen type I after treatment with the different sealer eluates was also measured, whereas cytotoxicity was determined using the DNA-specific fluorochrome Hoechst 33342. Finally, to assess cell morphology and attachment to the different sealers, hPDLSCs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). One-way analysis of variance (anova) followed by a Bonferroni post-test were performed (P Endodontic Journal. Published by John Wiley & Sons Ltd.

  1. Clinical and radiographic comparison of indirect pulp treatment using light-cured calcium silicate and mineral trioxide aggregate in primary molars: A randomized clinical trial

    Science.gov (United States)

    Menon, Navya P.; Varma, Balagopal R.; Janardhanan, Sureshkumar; Kumaran, Parvathy; Xavier, Arun Mamachan; Govinda, Bhat Sangeetha

    2016-01-01

    Aim: To clinically and radiographically evaluate the reparative dentin formation in indirect pulp treatment (IPT) using mineral trioxide aggregate (MTA) and light cured calcium silicate (TheraCal) in primary molars over a period of 6 months. Materials and Methods: A clinical trial on IPT on 43 primary molars in 21 patients between the age of 4–7 years, divided into two groups: 22 teeth in MTA group and 21 in TheraCal group. Measurement of the variation in dentin thickness was done on the digitalized radiograph at baseline, 3 months and 6 months using CorelDRAW X3 software. Results: Statistical analysis using an independent t-test for intragroup and intergroup comparison showed a significant increase in dentin thickness in both the MTA and TheraCal group (intragroup comparison [P MTA and TheraCal showed no statistical difference in reparative dentin formation (P > 0.05). Conclusion: Clinically and radiographically, both MTA and TheraCal are good IPT materials. The better handling characteristics and comparable reparative dentin-forming ability of TheraCal make this material an alternative to MTA in pediatric restorative procedures. PMID:27994414

  2. Evaluation and Comparison of Occurrence of Tooth Discoloration after the Application of Various Calcium Silicate-based Cements: An Ex Vivo Study.

    Science.gov (United States)

    Shokouhinejad, Noushin; Nekoofar, Mohammad H; Pirmoazen, Salma; Shamshiri, Ahmad R; Dummer, Paul M H

    2016-01-01

    Biodentine (Septodont, Saint Maur des Fossés, France), OrthoMTA (BioMTA, Seoul, Korea), and EndoSequence Root Repair Material (ERRM; Brasseler, Savannah, GA) have been developed to overcome the shortcomings of mineral trioxide aggregate (MTA). The purpose of this study was to compare tooth discoloration after the application of ProRoot MTA (Dentsply Tulsa Dental Products, Tulsa, OK) and 3 recently introduced calcium silicate-based cements in the presence and absence of blood. In total, 104 human anterior teeth were prepared; 96 were randomly divided into 2 groups (blood and saline contamination). Each group was subdivided into 4 experimental subgroups (n = 12) of ProRoot MTA, Biodentine, OrthoMTA, and ERRM that were used to fill the pulp chambers. The remaining 8 teeth served as the saline and blood groups. Color analysis of tooth crowns was performed using a spectroradiometer before the application of materials and at 24 hours, 1 month, and 6 months after application. Repeated measures analysis of variance was used to evaluate the effects of blood, material, and time on color change (ΔE*). Tooth color change in all experimental groups increased over time (P discolorations with materials in the presence of blood. However, in the absence of blood, Biodentine and ERRM exhibited less tooth discoloration than OrthoMTA. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  3. Influences of mesoporous zinc-calcium silicate on water absorption, degradability, antibacterial efficacy, hemostatic performances and cell viability to microporous starch based hemostat.

    Science.gov (United States)

    Hou, Yu; Xia, Yan; Pan, Yongkang; Tang, Songchao; Sun, Xiaofei; Xie, Yang; Guo, Han; Wei, Jie

    2017-07-01

    Efficacious hemostatic agents have significant potential application in visceral organ or large vessel arterial injure. In this study, mesoporous zinc-calcium silicate (m-ZCS) was synthesized, and microporous starch (MS) based hemostatic agents of m-ZCS/MS composites for hemorrhage control was fabricated. The results showed that the incorporation of m-ZCS into MS significantly enhanced the water absorption and degradability of the composites, which were dependent on the m-ZCS content. Moreover, the composites with antibacterial property could inhibit the growth of Escherichia coli (E. coli) and the antibacterial ratios increased with the m-ZCS content. The in vitro coagulation evaluation by using activated partial thromboplastin time (APTT) and prothrombin time (PT) revealed that the composites significantly activated the intrinsic and extrinsic pathway of coagulation cascade. In addition, for the animal model of rabbits in ear vein, skin, arterial and liver injuries, the hemostatic time of the composites obviously reduced with the increase of m-ZSC content, in which the composite with 15wt% m-ZCS content (15mZSC) showed remarkable efficacy on bleeding control. The composites could promote the viability of L929 cells, indicating no cytotoxicity of the composites. The results suggested that the m-ZCS/MS composites with excellent hemostatic and antibacterial properties might be a candidate for controlling bleeding and infection. Copyright © 2017. Published by Elsevier B.V.

  4. 3D printed scaffolds of calcium silicate-doped β-TCP synergize with co-cultured endothelial and stromal cells to promote vascularization and bone formation.

    Science.gov (United States)

    Deng, Yuan; Jiang, Chuan; Li, Cuidi; Li, Tao; Peng, Mingzheng; Wang, Jinwu; Dai, Kerong

    2017-07-17

    Synthetic bone scaffolds have potential application in repairing large bone defects, however, inefficient vascularization after implantation remains the major issue of graft failure. Herein, porous β-tricalcium phosphate (β-TCP) scaffolds with calcium silicate (CS) were 3D printed, and pre-seeded with co-cultured human umbilical cord vein endothelial cells (HUVECs) and human bone marrow stromal cells (hBMSCs) to construct tissue engineering scaffolds with accelerated vascularization and better bone formation. Results showed that in vitro β-TCP scaffolds doped with 5% CS (5%CS/β-TCP) were biocompatible, and stimulated angiogenesis and osteogenesis. The results also showed that 5%CS/β-TCP scaffolds not only stimulated co-cultured cells angiogenesis on Matrigel, but also stimulated co-cultured cells to form microcapillary-like structures on scaffolds, and promoted migration of BMSCs by stimulating co-cultured cells to secrete PDGF-BB and CXCL12 into the surrounding environment. Moreover, 5%CS/β-TCP scaffolds enhanced vascularization and osteoinduction in comparison with β-TCP, and synergized with co-cultured cells to further increase early vessel formation, which was accompanied by earlier and better ectopic bone formation when implanted subcutaneously in nude mice. Thus, our findings suggest that porous 5%CS/β-TCP scaffolds seeded with co-cultured cells provide new strategy for accelerating tissue engineering scaffolds vascularization and osteogenesis, and show potential as treatment for large bone defects.

  5. ToF-SIMS images and spectra of biomimetic calcium silicate-based cements after storage in solutions simulating the effects of human biological fluids

    Science.gov (United States)

    Torrisi, A.; Torrisi, V.; Tuccitto, N.; Gandolfi, M. G.; Prati, C.; Licciardello, A.

    2010-01-01

    ToF-SIMS images were obtained from a section of a tooth, obturated by means of a new calcium-silicate based cement (wTCF) after storage for 1 month in a saline solutions (DPBS), in order to simulate the body fluid effects on the obturation. Afterwards, ToF-SIMS spectra were obtained from model samples, prepared by using the same cement paste, after storage for 1 month and 8 months in two different saline solutions (DPBS and HBSS). ToF-SIMS spectra were also obtained from fluorine-free cement (wTC) samples after storage in HBSS for 1 month and 8 months and used for comparison. It was found that the composition of both the saline solution and the cement influenced the composition of the surface of disks and that longer is the storage greater are the differences. Segregation phenomena occur both on the cement obturation of the tooth and on the surface of the disks prepared by using the same cement. Indirect evidences of formation of new crystalline phases are supplied.

  6. 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 < .05). In this period, the weight loss with 10% Ca(OCl)(2) differed from Chlorax at all time intervals except at 5 and 35 minutes (P < .05); 5% Ca(OCl)(2) showed no significant differences with 10% Ca(OCl)(2) and 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.

  7. Effect of sodium polyacrylate molecular weight on the crystallogenesis of calcium carbonate

    Science.gov (United States)

    Jada, A.; Ait Akbour, R.; Jacquemet, C.; Suau, J. M.; Guerret, O.

    2007-08-01

    Aqueous solutions of sodium polyacrylates (NaPA) series having molecular weights ( Mw) ranging from 2540 to 9890 g mol -1 are used as precipitation media to control the size and shape of calcium carbonate (CaCO 3) particles. The retarding effect of polyacrylates on CaCO 3 nucleation is evidenced by the increase of the induction time, τ, of the precipitated CaCO 3, from τ=55 s in the absence of additives, to τ values in the range 100-2500 s in the presence of NaPA samples. The data also show the coexistence of two polymorphs, calcite and vaterite, for CaCO 3 particles as prepared in the presence of NaPA samples. The vaterite fraction, fv, varies in all instances with the polymer concentration, Cpoly (g. L -1), and reaches its maximum value, fv,max at optimal ratio, R (mol. g -1), of Ca ion to polymer (NaPA), R=[Ca]/([NaPA]=Cpoly). No simple general trend is found to explain the influence of the molecular weight ( Mw) of NaPA on the induction time, τ, and on the vaterite fraction, fv, since these two parameters are found to vary with Cpoly and Mw. However, under certain experimental conditions, an optimum polymer molecular weight ( Mw=5530 g mol -1) of the NaPA series, gives the highest values of fv,max and τ. Such optimum indicates the influence of Mw of NaPA on CaCO 3 nucleation and growth, and it is related to the surface density and the rate of adsorption of the polymer onto the growing crystal. The CaCO 3 particle size is reduced from about 20 μm, as obtained in the control experiment, to sizes varying in the range 2-8 μm in the presence NaPA samples. Polymers having low Mw values ( Mw<5000 g mol -1) are found to be more efficient in reducing the CaCO 3 particle size.

  8. Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

    Science.gov (United States)

    Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

    2017-11-01

    Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH)2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH)2-glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl2) at room temperature, but that in Ca(OH)2-water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH)2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Évaluation des teneurs sériques en sodium et en calcium et de leurs ...

    African Journals Online (AJOL)

    L'objectif: le but de cette étude était d'évaluer les teneurs sériques en sodium et en calcium ainsi que leurs intensités de transfert dans le CMPF au cours de la gestation chez les chèvres élevées à Lubumbashi à zone tropicale. Méthodologie et résultats: Cette recherche a été menée sur 45 sérums dont 15 provenant de ...

  10. Comparative evaluation of a dentifrice containing calcium sodium phosphosilicate to a dentifrice containing potassium nitrate for dentinal hypersensitivity: A clinical study

    Directory of Open Access Journals (Sweden)

    Tanya Satyapal

    2014-01-01

    Full Text Available Background: Calcium sodium phosphosilicate is a recently introduced desensitizing agent which acts by occluding the dentinal tubules and also resists acid decalcification. This study was designed to assess the efficacy of a new toothpaste containing 5% calcium sodium phosphosilicate for the treatment of dentinal hypersensitivity and also compare it with 5% potassium nitrate. Materials and Methods: Sixty patients with the chief complaint of dentinal hypersensitivity were enrolled and randomly divided into two groups. The visual analog scale (VAS scores were taken for water and air stimuli at baseline, 3 weeks after usage of the respective toothpaste, and 3 weeks after discontinuation of the respective toothpaste. Results: Both the groups showed reduction in hypersensitivity scores at 3 weeks and 6 weeks for air stimulus and cold water. The calcium sodium phosphosilicate group, however, showed significantly reduction in hypersensitivity compared to the potassium nitrate group at any time point for both measures of hypersensitivity. Conclusion: The 5% calcium sodium phosphosilicate group showed immense reduction in dentinal hypersensitivity symptoms. The 5% calcium sodium phosphosilicate showed prolonged effects even after discontinuation as compared to 5% potassium nitrate, due to its dentinal tubular occlusion property.

  11. Calcium isotopic fractionation in mantle peridotites by melting and metasomatism and Ca isotope composition of the Bulk Silicate Earth

    Science.gov (United States)

    Kang, Jin-Ting; Ionov, Dmitri A.; Liu, Fang; Zhang, Chen-Lei; Golovin, Alexander V.; Qin, Li-Ping; Zhang, Zhao-Feng; Huang, Fang

    2017-09-01

    To better constrain the Ca isotopic composition of the Bulk Silicate Earth (BSE) and explore the Ca isotope fractionation in the mantle, we determined the Ca isotopic composition of 28 peridotite xenoliths from Mongolia, southern Siberia and the Siberian craton. The samples are divided in three chemical groups: (1) fertile, unmetasomatized lherzolites (3.7-4.7 wt.% Al2O3); (2) moderately melt-depleted peridotites (1.3-3.0 wt.% Al2O3) with no or very limited metasomatism (LREE-depleted cpx); (3) strongly metasomatized peridotites (LREE-enriched cpx and bulk rock) further divided in subgroups 3a (harzburgites, 0.1-1.0% Al2O3) and 3b (fertile lherzolites, 3.9-4.3% Al2O3). In Group 1, δ44/40Ca of fertile spinel and garnet peridotites, which experienced little or no melting and metasomatism, show a limited variation from 0.90 to 0.99‰ (relative to SRM 915a) and an average of 0.94 ± 0.05‰ (2SD, n = 14), which defines the Ca isotopic composition of the BSE. In Group 2, the δ44/40Ca is the highest for three rocks with the lowest Al2O3, i.e. the greatest melt extraction degrees (average 1.06 ± 0.04 ‰, i.e. ∼0.1‰ heavier than the BSE estimate). Simple modeling of modal melting shows that partial melting of the BSE with 103 ln ⁡αperidotite-melt ranging from 0.10 to 0.25 can explain the Group 2 data. By contrast, δ44/40Ca in eight out of nine metasomatized Group 3 peridotites are lower than the BSE estimate. The Group 3a harzburgites show the greatest δ44/40Ca variation range (0.25-0.96‰), with δ44/40Ca positively correlated with CaO and negatively correlated with Ce/Eu. Chemical evidence suggests that the residual, melt-depleted, low-Ca protoliths of the Group 3a harzburgites were metasomatized, likely by carbonate-rich melts/fluids. We argue that such fluids may have low (≤0.25‰) δ44/40Ca either because they contain recycled crustal components or because Ca isotopes, similar to trace elements and their ratios, may be fractionated by kinetic and

  12. Actions of a hydrogen sulfide donor (NaHS) on transient sodium, persistent sodium, and voltage-gated calcium currents in neurons of the subfornical organ.

    Science.gov (United States)

    Kuksis, Markus; Ferguson, Alastair V

    2015-09-01

    Hydrogen sulfide (H2S) is an endogenously found gasotransmitter that has been implicated in a variety of beneficial physiological functions. This study was performed to investigate the cellular mechanisms underlying actions of H2S previously observed in subfornical organ (SFO), where H2S acts to regulate blood pressure through a depolarization of the membrane and an overall increase in the excitability of SFO neurons. We used whole cell patch-clamp electrophysiology in the voltage-clamp configuration to analyze the effect of 1 mM NaHS, an H2S donor, on voltage-gated potassium, sodium, and calcium currents. We observed no effect of NaHS on potassium currents; however, both voltage-gated sodium currents (persistent and transient) and the N-type calcium current had a depolarized activation curve and an enhanced peak-induced current in response to a series of voltage-step and ramp protocols run in the control and NaHS conditions. These effects were not responsible for the previously observed depolarization of the membrane potential, as depolarizing effects of H2S were still observed following block of these conductances with tetrodotoxin (5 μM) and ω-conotoxin-GVIA (100 nM). Our studies are the first to investigate the effect of H2S on a variety of voltage-gated conductances in a single brain area, and although they do not explain mechanisms underlying the depolarizing actions of H2S on SFO neurons, they provide evidence of potential mechanisms through which this gasotransmitter influences the excitability of neurons in this important brain area as a consequence of the modulation of multiple ion channels. Copyright © 2015 the American Physiological Society.

  13. The effect of sodium hypochlorite application on the success of calcium hydroxide and mineral trioxide aggregate pulpotomies in primary teeth.

    Science.gov (United States)

    Akcay, Merve; Sari, Saziye

    2014-01-01

    This study's purpose was to evaluate the success of calcium hydroxide (CH) and mineral trioxide aggregate (MTA) pulpotomies following the use of five percent sodium hypochlorite (NaOCl) as an antibacterial agent to clean the chamber prior to application of the pulpotomy agent. A total of 128 teeth were randomly divided into two pulpotomy groups (CH or MTA). The teeth in each pulpotomy group, CH and MTA, were further randomly divided into subgroups to receive either the NaOCl (experimental) or saline (control) cleaning agent prior to applying the pulpotomy agent. The treatments were followed clinically and radiographically for 12 months. The radiographic success rates were 84 percent for CH NaOCl, 74 percent for CH saline control, 97 percent for MTA NaOCl, and 100 percent for MTA saline control. There were no significant differences between the radiographic success rates in the CH and MTA subgroups (CH NaOCl-CH control and MTA NaOCl-MTA control); no significant differences were observed when comparing the CH NaOCl-MTA NaOCl groups and the CH NaOCl-MTA control groups. Use of sodium hypochlorite as an antibacterial agent prior to application of the pulpotomy agent improved the success of calcium hydroxide pulpotomies to equal the success of mineral trioxide aggregate pulpotomies for observation up to 12 months.

  14. Phylogeny unites animal sodium leak channels with fungal calcium channels in an ancient, voltage-insensitive clade.

    Science.gov (United States)

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

    2012-12-01

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

  15. 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.

  16. The effect of calcium/sodium ratio on the dynamic adsorption of sodium dodecyl benzene sulfonate (SDBS) onto water/air interfaces. Evaluation of critical micelle concentrations, diffusion coefficients and molecular areas

    OpenAIRE

    Olsen, Arnt Ove Jektvik

    2016-01-01

    Test how calcium/sodium-ratio affect the dynamic adsorption of sodium dodecyl benzene sulfonate (SDBS) onto water/air interfaces where the ionic strength is kept constant at 20 mM, with the use of maximum bubble pressure tensiometer. With evaluation of critical micelle concentrations, molecular areas and diffusion coefficients. Where short time aproximation of ward and tordai equation is used to find the diffusion coeffician

  17. Calcium

    Science.gov (United States)

    ... and blood vessels contract and expand, to secrete hormones and enzymes and to send messages through the nervous system. It is important to get plenty of calcium in the foods you eat. Foods rich in calcium include Dairy products such as milk, cheese, and yogurt Leafy, green vegetables Fish with ...

  18. Mechanical and physical behavior of newly developed functionally graded materials and composites of stainless steel 316L with calcium silicate and hydroxyapatite.

    Science.gov (United States)

    Ataollahi Oshkour, Azim; Pramanik, Sumit; Mehrali, Mehdi; Yau, Yat Huang; Tarlochan, Faris; Abu Osman, Noor Azuan

    2015-09-01

    This study aimed to investigate the structural, physical and mechanical behavior of composites and functionally graded materials (FGMs) made of stainless steel (SS-316L)/hydroxyapatite (HA) and SS-316L/calcium silicate (CS) employing powder metallurgical solid state sintering. The structural analysis using X-ray diffraction showed that the sintering at high temperature led to the reaction between compounds of the SS-316L and HA, while SS-316L and CS remained intact during the sintering process in composites of SS-316L/CS. A dimensional expansion was found in the composites made of 40 and 50 wt% HA. The minimum shrinkage was emerged in 50 wt% CS composite, while the maximum shrinkage was revealed in samples with pure SS-316L, HA and CS. Compressive mechanical properties of SS-316L/HA decreased sharply with increasing of HA content up to 20 wt% and gradually with CS content up to 50 wt% for SS-316L/CS composites. The mechanical properties of the FGM of SS-316L/HA dropped with increase in temperature, while it was improved for the FGM of SS-316L/CS with temperature enhancement. It has been found that the FGMs emerged a better compressive mechanical properties compared to both the composite systems. Therefore, the SS-316L/CS composites and their FGMs have superior compressive mechanical properties to the SS-316L/HA composites and their FGMs and also the newly developed FGMs of SS-316L/CS with improved mechanical and enhanced gradation in physical and structural properties can potentially be utilized in the components with load-bearing application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Evaluation of the filling ability of artificial lateral canals using calcium silicate-based and epoxy resin-based endodontic sealers and two gutta-percha filling techniques.

    Science.gov (United States)

    Fernández, R; Restrepo, J S; Aristizábal, D C; Álvarez, L G

    2016-04-01

    To evaluate the ability of a calcium silicate-based sealer (iRoot SP) and an epoxy resin-based sealer (Topseal) using two gutta-percha filling techniques to fill artificial lateral canals (ALCs). Seventy single-rooted human teeth were selected. Ten of these were used to obtain pilot data. Three ALCs were produced on mesial and distal surfaces of each root, one in each third, using size 10 engine reamers. The roots were randomly assigned to four experimental groups according to the filling technique and sealer used: 1, cold gutta-percha (single-point technique) with iRoot SP (SP-iR); 2, cold gutta-percha (single-point technique) with Topseal (SP-T); 3, continuous wave of condensation technique with iRoot SP (CWC-iR); and 4, continuous wave of condensation technique with Topseal (CWC-T). Digital periapical radiographs were taken. After the sealer had set, the roots were demineralized, cleared in methyl-salicylate and examined under a stereomicroscope. The depth of penetration of sealer and/or gutta-percha into the ALC was scored using a 5-point system, conducting an analysis on four surfaces. Filling scores of 0-1 were considered not acceptable, whilst scores of 2-4 were considered acceptable. Pearson's chi-square test was used to compare the experimental groups (P epoxy resin-based sealer with both filling techniques was effective in artificial filling lateral canals. © 2015 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  20. Effect of polymers on the nanostructure and on the carbonation of calcium silicate hydrates: a scanning transmission X-ray microscopy study

    KAUST Repository

    Ha, J.

    2011-09-07

    This study investigated the effects of organic polymers (polyethylene glycol and hexadecyltrimethylammonium) on structures of calcium silicate hydrates (C-S-H) which is the major product of Portland cement hydration. Increased surface areas and expansion of layers were observed for all organic polymer modified C-S-H. The results from attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopic measurements also suggest lowered water contents in the layered structures for the C-S-H samples that are modified by organic polymers. Scanning transmission X-ray microscopy (STXM) results further supports this observation. We also observed difference in the extent of C-S-H carbonation due to the presence of organic polymers. No calcite formed in the presence of HDTMA whereas formation of calcite was observed with C-S-H sample modified with PEG. We suggest that the difference in the carbonation reaction is possibly due to the ease of penetration and diffusion of the CO 2. This observation suggests that CO 2 reaction strongly depends on the presence of organic polymers and the types of organic polymers incorporated within the C-S-H structure. This is the first comprehensive study using STXM to quantitatively characterize the level of heterogeneity in cementitious materials at high spatial and spectral resolutions. The results from BET, XRD, ATR-FTIR, and STXM measurements are consistent and suggest that C-S-H layer structures are significantly modified due to the presence of organic polymers, and that the chemical composition and structural differences among the organic polymers determine the extent of the changes in the C-S-H nanostructures as well as the extent of carbonation reaction. © 2011 Springer Science+Business Media, LLC.

  1. A Comparison in Mechanical Properties of Cermets of Calcium Silicate with Ti-55Ni and Ti-6Al-4V Alloys for Hard Tissues Replacement

    Directory of Open Access Journals (Sweden)

    Azim Ataollahi Oshkour

    2014-01-01

    Full Text Available This study investigated the impact of calcium silicate (CS content on composition, compressive mechanical properties, and hardness of CS cermets with Ti-55Ni and Ti-6Al-4V alloys sintered at 1200°C. The powder metallurgy route was exploited to prepare the cermets. New phases of materials of Ni16Ti6Si7, CaTiO3, and Ni31Si12 appeared in cermet of Ti-55Ni with CS and in cermet of Ti-6Al-4V with CS, the new phases Ti5Si3, Ti2O, and CaTiO3, which were emerged during sintering at different CS content (wt%. The minimum shrinkage and density were observed in both groups of cermets for the 50 and 100 wt% CS content, respectively. The cermets with 40 wt% of CS had minimum compressive Young’s modulus. The minimum of compressive strength and strain percentage at maximum load were revealed in cermets with 50 and 40 wt% of CS with Ti-55Ni and Ti-6Al-4V cermets, respectively. The cermets with 80 and 90 wt% of CS showed more plasticity than the pure CS. It concluded that the composition and mechanical properties of sintered cermets of Ti-55Ni and Ti-6Al-4V with CS significantly depend on the CS content in raw cermet materials. Thus, the different mechanical properties of the cermets can be used as potential materials for different hard tissues replacements.

  2. Retreatability of three calcium silicate-containing sealers and one epoxy resin-based root canal sealer with four different root canal instruments.

    Science.gov (United States)

    Donnermeyer, David; Bunne, Clarissa; Schäfer, Edgar; Dammaschke, Till

    2017-06-22

    The objective of the study was to compare the retreatability of three calcium silicate-containing sealers (BioRoot RCS, MTA Fillapex, Endo C.P.M.) and an epoxy resin-based sealer (AH Plus) with different root canal instruments (Hedström files, Reciproc R40, Mtwo retreatment file R 25/.05 + Mtwo 40/.06, and F6 SkyTaper) concerning sealer remnants and retreatment time. Root canals of 192 teeth were instrumented with Reciproc R40. All root canals were obturated using the single-cone technique with Reciproc R40 gutta-percha and one of the sealers (n = 48 per sealer). Two months later, retreatment was performed using one of the mentioned instruments (n = 12 per instrument and sealer). The roots were split longitudinally, and both halves were investigated using light microscopy. The percentage of sealer remnants covering the root canal wall was evaluated using the software ImageJ. The time required for retreatment was recorded. Statistical analysis was performed using two-way ANOVA and Student-Newman-Keuls post hoc test. Regarding the percentage of root canal filling remnants as well as retreatment time, two-way ANOVA indicated that the results were significantly affected by the sealer (p instrument used (p instruments allowed significantly faster retreatment than the other instruments (p instruments was superior compared to hand instrumentation. Engine-driven NiTi instruments are better suited to remove root canal fillings than stainless steel Hedström files.

  3. Regulation of physicochemical properties, osteogenesis activity, and fibroblast growth factor-2 release ability of β-tricalcium phosphate for bone cement by calcium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Su, Ching-Chuan [Antai Medical Care Cooperation Antai Tian-Sheng Memorial Hospital, Pingtung, Taiwan (China); Kao, Chia-Tze; Hung, Chi-Jr [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Chen, Yi-Jyun [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Dental Department, Taichung Hospital, Ministry of Health and Welfare, Taichung City, Taiwan (China); Huang, Tsui-Hsien, E-mail: thh@csmu.edu.tw [School of Dentistry, Chung Shan Medical University, Taichung, Taiwan (China); Department of Dentistry, Chung Shan Medical University Hospital, Taichung, Taiwan (China); Shie, Ming-You, E-mail: eviltacasi@gmail.com [Institute of Oral Science, Chung Shan Medical University, Taichung, Taiwan (China)

    2014-04-01

    β-Tricalcium phosphate (β-TCP) is an osteoconductive material. For this research we have combined it with a low degradation calcium silicate (CS) to enhance its bioactive and osteostimulative properties. To check its effectiveness, a series of β-TCP/CS composites with different ratios were prepared to make new bioactive and biodegradable biocomposites for bone repair. Formation of bone-like apatite, the diametral tensile strength, and weight loss of composites were considered before and after immersion in simulated body fluid (SBF). In addition, we also examined the effects of fibroblast growth factor-2 (FGF-2) released from β-TCP/CS composites and in vitro human dental pulp cell (hDPC) and studied its behavior. The results showed that the apatite deposition ability of the β-TCP/CS composites was enhanced as the CS content was increased. For composites with more than 50% CS contents, the samples were completely covered by a dense bone-like apatite layer. At the end of the immersion point, weight losses of 19%, 24%, 33%, 42%, and 51% were observed for the composites containing 0%, 30%, 50%, 70% and 100% β-TCP cements, respectively. In vitro cell experiments show that the CS-rich composites promote human dental pulp cell (hDPC) proliferation and differentiation. However, when the CS quantity in the composite is less than 70%, the amount of cells and osteogenesis protein of hDPCs was stimulated by FGF-2 released from β-TCP/CS composites. The combination of FGF-2 in degradation of β-TCP and osteogenesis of CS gives a strong reason to believe that these calcium-based composite cements may prove to be promising bone repair materials. - Highlights: • CS improved physicochemical properties and osteogenic activity of β-TCP. • The higher the CS in the cement, the shorter the setting time and the higher the DTS. • The cell behavior was stimulated by FGF-2 released from composite containing 50% CS. • β-TCP/CS composite with FGF-2 has optimal properties for

  4. COMPARISON OF SOL-GEL SILICATE COATINGS ON Ti SUBSTRATE

    Directory of Open Access Journals (Sweden)

    DIANA HORKAVCOVÁ

    2012-12-01

    Full Text Available The objective of the submitted work was to prepare and to characterize two types of silicate coatings prepared by the sol-gel method using the dip-coating technique on a titanium substrate. Efforts have been made to use mechanical properties of bio-inert titanium and bioactive properties of a silicate layer enriched with an admixture of compounds identified below. The first group consisted of silicate coatings containing silver, brushite and monetite. The other group of silicate coatings contained calcium nitrate and triethyl phosphate. Mechanically and chemically treated titanium substrates were dipped into sols and dried and fired. Silicate coatings from the first group were also chemically treated in 10 mol.l-1 solution of sodium hydroxide. All coatings were measured to determine their adhesive and bioactive properties and furthermore the antibacterial properties were tested in the case of first group. Surfaces of the coated substrates were investigated after the firing and after the individual tests with optical and electron microscopy and X-ray microdiffraction. A tape test demonstrated excellent adhesive property of all coatings to the substrate, classified with degree 5. A static in vitro test demonstrated bioactivity of nearly all the coatings. The basic silicate coating from the first group and one type of coating from the second group were identified as inert. Antibacterial properties of silicate coatings containing silver showed to be different when tested against Escherichia coli bacteria. A complete inhibition of the growth of bacteria under our experimental conditions was observed for the coating containing silver and monetite and a partial inhibition of the growth of bacteria for coatings containing silver and silver in combination with brushite.

  5. Physicochemical changes in dry-cured hams salted with potassium, calcium and magnesium chloride as a partial replacement for sodium chloride.

    Science.gov (United States)

    Aliño, M; Grau, R; Toldrá, F; Barat, J M

    2010-10-01

    The reduction of added sodium chloride in dry-cured ham has been proposed to reduce dietary sodium intake in Mediterranean countries. The effect of substituting sodium chloride with potassium chloride, calcium chloride and magnesium chloride on some physicochemical characteristics of dry-cured ham during processing was evaluated. The results showed that hams salted with a mixture of sodium and potassium chloride registered higher salt concentrations and lower water contents and thus, needed less time to reach the required weight loss at the end of the process. The opposite effect was observed when calcium and magnesium chloride were added to the salt mixture. The observed differences in the texture and colour parameters were mainly due to differences in water and salt content. Copyright (c) 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2004-09-01

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

  7. USE OF SODIUM ALUMINATE IN FOUNDRY PAINTS

    Directory of Open Access Journals (Sweden)

    O. S. Komarov

    2016-01-01

    Full Text Available Comparison of the properties of the casting paints based on sodium silicate and sodium aluminat, and sodium aluminat as an additive to the ink for the organic binder has shown that sodium aluminat provides a higher level of properties than sodium silicate and aluminat, in addition to an organic paint binder improves properties

  8. Calcium

    Science.gov (United States)

    ... from dietary supplements are linked to a greater risk of kidney stones, especially among older adults. But calcium from foods does not appear to cause kidney stones. For most people, other factors (such as not drinking enough fluids) probably have ...

  9. Obtaining calcium silicates by using solid residues as precursors. Influence of water in the process of mixing reagents; Obtencin de silicatos de calcio empleando como precursores residuos solidos. Influencia del mezclado de reactivos en fase seca o fase humeda

    Energy Technology Data Exchange (ETDEWEB)

    Felipe-Sese, M.; Eliche-Quesada, D.; Corpas-Iglesias, F. A.

    2011-07-01

    The suitability of re-using residues marble, remaining from cutting marble, as a source of calcium-oxide, as well as the resultant ashes from the combustion of the wastes generated in the process of manufacturing boards from derivates of wood, as a source of silica, as raw material for the production of calcium silicate products has been determined. First of all, the influence of water has been studied in the initial phase of mixing residues. Marble and ashes have been mixed in molar relation CaO:SiO{sub 2} of 1:1 using two different ways: using a planetary ball mill (while in solid state) or agitating at 90 degree centigrade (2 h) using a 60 wt% of water (while in humid state). Later, both mixtures were sintered at 1100 degree centigrade (24 h). In order to use the obtained calcium-silicates as ceramic insulating thermal materials, the samples were compressed at 15 Tm obtaining bricks from which the technological properties have been studied. The ceramic materials obtained from mixing the residues in dry phase, as well as those obtained in the wet phase, can be used as thermal insulators, showing values of conductivity of 0.18 and 0.12 w/m{sup 2}K, with an elevated resistance to compressive strength. (Author) 14 refs.

  10. 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 (Ascorbate and Magnesium Ascorbate are described as antioxidants and skin conditioning agents--miscellaneous for use in cosmetics, but are not currently used. Sodium Ascorbyl Phosphate functions as an antioxidant in cosmetic products and is used at concentrations ranging from 0.01% to 3%. Magnesium Ascorbyl Phosphate functions as an antioxidant in cosmetics and was reported being used at concentrations from 0.001% to 3%. Sodium Ascorbate also functions as an antioxidant in cosmetics at concentrations from 0.0003% to 0.3%. Related ingredients (Ascorbyl Palmitate, Ascorbyl Dipalmitate, Ascorbyl Stearate, Erythorbic Acid, and Sodium Erythorbate) have been previously reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel and found "to be safe for use as cosmetic ingredients in the present practices of good use." Ascorbic Acid is a generally recognized as safe (GRAS) substance for use as a chemical preservative in foods and as a nutrient and/or dietary supplement. Calcium Ascorbate and Sodium Ascorbate are listed as GRAS substances for use as chemical preservatives. L-Ascorbic Acid is readily and reversibly oxidized to L-dehydroascorbic acid and both forms exist in equilibrium in the body. Permeation rates of Ascorbic Acid through whole and stripped mouse skin were 3.43 +/- 0.74 microg/cm(2)/h and 33.2 +/- 5.2 microg/cm(2)/h. Acute oral and parenteral studies in mice, rats, rabbits, guinea pigs, dogs, and cats demonstrated little toxicity. Ascorbic Acid and Sodium Ascorbate acted

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

    Directory of Open Access Journals (Sweden)

    Manjanna Kolammanahalli Mallappa

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

  14. Impacts of sodium chlorite combined with calcium chloride, and calcium ascorbate on microbial population, browning, and quality of fresh-cut rose apple

    Directory of Open Access Journals (Sweden)

    Sunthon Mola

    2016-09-01

    Full Text Available Microbial activity and browning were minimized and fresh-cut rose apple quality was maintained using sodium chlorite (SC combined with calcium chloride (CC and calcium ascorbate (CaAs and by investigating the optimal concentration and dipping time of SC for inhibiting microbial activity and browning. Fresh-cut rose apple samples were dipped in SC solution at 100 mg/L and 200 mg/L for 1 min and 3 min, with filtered water and non-dipped samples as controls. All samples were kept at 4 ± 2 °C for 9 d. The results showed that 200 mg/L SC for 3 min was the best treatment to inhibit microbial growth (total bacteria, yeast and molds, Escherichia coli and coliforms, delay browning and polyphenol oxidase (PPO activity of fresh-cut rose apples, but could not maintain the fresh firmness. A firmness experiment was conducted by dipping fresh-cut rose apples in 200 mg/L SC and in 200 mg/L SC combined with 20 g/L CC and 20 g/L CaAs (SC + CC + CaAs for 3 min before storage at 4 ± 2 °C for 9 d. Samples immersed in filtered water were used as the control. The combined treatment delayed microbial contamination and browning by reducing the PPO activity and the accumulation of phenolic content, and maintained the fresh firmness of fresh-cut rose apples. Thus, the combination treatment of SC + CC + CaAs solution can protect fresh-cut rose apples against microbial contamination and delay browning and maintain firmness.

  15. First investigations on the quaternary system Na2O-K2O-CaO-SiO2: synthesis and crystal structure of the mixed alkali calcium silicate K1.08Na0.92Ca6Si4O15

    Science.gov (United States)

    Kahlenberg, Volker; Mayerl, Michael Jean-Philippe; Schmidmair, Daniela; Krüger, Hannes; Tribus, Martina

    2017-09-01

    In the course of an exploratory study on the quaternary system Na2O-K2O-CaO-SiO2 single crystals of the first anhydrous sodium potassium calcium silicate have been obtained from slow cooling of a melt in the range between 1250 and 1050 °C. Electron probe micro analysis suggested the following idealized molar ratios of the oxides for the novel compound: K2O:Na2O:CaO:SiO2 = 1:1:12:8 (or KNaCa6Si4O15). Single-crystal diffraction measurements on a crystal with chemical composition K1.08Na0.92Ca6Si4O15 resulted in the following basic crystallographic data: monoclinic symmetry, space group P 21/c, a = 8.9618(9) Å, b = 7.3594(6) Å, c = 11.2453(11) Å, β= 107.54(1)°, V = 707.2(1) Å3, Z = 2. Structure solution was performed using direct methods. The final least-squares refinement converged at a residual of R(|F|) = 0.0346 for 1288 independent reflections and 125 parameters. From a structural point of view, K1.08Na0.92Ca6Si4O15 belongs to the group of mixed-anion silicates containing [Si2O7]- and [SiO4]-units in the ratio 1:2. The mono- and divalent cations occupy a total of four crystallographically independent positions located in voids between the tetrahedra. Three of these sites are exclusively occupied by calcium. The fourth site is occupied by 54(1)% K and 46%(1) Na, respectively. Alternatively, the structure can be described as a heteropolyhedral framework based on corner-sharing silicate tetrahedra and [CaO6]-octahedra. The network can build up from kröhnkite-like [Ca(SiO4)2O2]-chains running along [001]. A detailed comparison with other A2B6Si4O15-compounds including topological and group-theoretical aspects is presented.

  16. Influence of the redox state on the neptunium sorption under alkaline conditions. Batch sorption studies on titanium dioxide and calcium silicate hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Tits, Jan; Laube, Andreas; Wieland, Erich [Paul Scherrer Institute (PSI), Villigen (Switzerland). Lab. for Waste Management; Gaona, Xavier [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany). Inst. for Nuclear Waste Disposal

    2014-07-01

    Wet chemistry experiments were carried out to investigate the effect of the redox state and aqueous speciation on the uptake of neptunium by titanium dioxide (TiO{sub 2}) and by calcium silicate hydrates (C-S-H) under alkaline conditions. TiO{sub 2} was chosen as a reference sorbent to determine the surface complexation behaviour of neptunium under alkaline conditions. C-S-H phases are important constituents of cement and concrete. They may contribute significantly to radionuclide retention due to their high recrystallization rates making incorporation the dominating sorption mechanism for many radionuclides (e.g. the actinides) on these materials. The sorption of neptunium on both solids was found to depend strongly on the degree of hydrolysis. On TiO{sub 2}R{sub d} values for Np(IV), Np(V) and Np(VI) are identical at pH = 10 and decrease with progressing hydrolysis in case of Np(V) and Np(VI). On C-S-H phases, R{sub d} values for the three redox states are also identical at pH = 10. While the R{sub d} values for Np(VI) sorption on C-S-H phases decrease with progressing hydrolysis, the R{sub d} values for Np(IV) and Np(V) sorption are not affected by the pH. In addition to the effect of hydrolysis, the presence of Ca is found to promote Np(V) and Np(VI) sorption on TiO{sub 2} whereas on C-S-H phases, the present wet chemistry data do not give unambiguous evidence. Thus, the aqueous speciation appears to have a similar influence on the sorption of the actinides on both types of solids despite the different sorption mechanism. The similar R{sub d} values for Np(IV,V,VI) sorption at pH = 10 can be explained qualitatively by invoking inter-ligand electrostatic repulsion between OH groups in the coordination sphere of Np(V) and Np(VI). This mechanism was proposed earlier in the literature for the prediction of actinide complexation constants with inorganic ligands. A limiting coordination number for each Np redox state, resulting from the inter-ligand electrostatic

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

    Science.gov (United States)

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

    2000-03-01

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

  18. Calcium chloride and sodium phosphate in neonatal parenteral nutrition containing TrophAmine: precipitation studies and aluminum content.

    Science.gov (United States)

    Migaki, Evelyn A; Melhart, Brian J; Dewar, Christina J; Huston, Robert K

    2012-07-01

    The objectives were to determine concentrations of calcium chloride (CaCl) and sodium phosphate (NaPhos) that can be safely added to TrophAmine-based parenteral nutrition (PN) and to measure aluminum (Al) concentrations in PN solutions containing CaCl and NaPhos vs those containing calcium gluconate (CaGlu) and potassium phosphate (KPhos). In study A, PN solutions containing varying amounts of TrophAmine, CaCl, and NaPhos were compounded and then evaluated visually for precipitation. In study B, Al concentrations were measured in PN solutions containing CaCl and NaPhos (S1), CaGlu and NaPhos (S2), or CaGlu and KPhos (S3). Study A showed that a maximum phosphorus concentration of 15 mmol/L could be added to a solution containing 12.5 mmol/L of calcium without evidence of precipitation when the amino acid (AA) concentration reached ≥3 g/dL (3%). In study B, the mean (range) Al concentrations were S1 = 2.2 (1.9-2.4), S2 = 8.5 (7.8-9.3), and S3 = 11.7 (10.8-12.2) µmol/L (means of 6.0, 22.9, and 31.5 micrograms/dL, respectively). The data can provide a guide for compounding neonatal PN solutions containing TrophAmine, CaCl, and NaPhos. More studies are needed to determine the long-term effects of substituting CaCl for CaGlu in PN solutions for neonates. Substituting CaCl and NaPhos for CaGlu and KPhos significantly decreases Al concentrations in PN and potential Al exposure of neonatal patients.

  19. 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.

  20. NON-AUTOCLAVE SILICATE BRICK

    Directory of Open Access Journals (Sweden)

    V. N. Yaglov

    2015-01-01

    Full Text Available The paper proposes a technology for obtaining bricks on the basis of lime-silica mixtures where chemical interactions are practically completely realized in dispersive state at the stage of preparation of binding contact maturing and raw mixture as a whole. The role of forming operation (moulding is changed in principle because in this case conversion of dispersive system into a rock-like solid occurs and due to this the solid obtains complete water-resistance in contact with water immediately after forming operation. Theoretical basis for the developed technology is capability of silicate dispersive substances (hydrated calcium silicate to transit in non-stable state, to form a rock-like water-resistant solid in the moment of mechanical load application during forming process. Specific feature of the proposed method is an exclusion of additional operations for autoclaving of products from the process of obtaining a silicate brick.Synthetic hydrated calcium silicate in contrast to natural ones are more uniform in composition and structure, they contain less impurities and they are characterized by dispersive composition and due to the mentioned advantages they find wider practical application. Contact-condensation binders permit to manipulate product properties on their basis and ensure maximum correspondence to the requirements of the concrete application. Raw material sources for obtaining synthetic hydrated calcium silicates are practically un-limited because calcium-silicon containing substances are found as in various technogenic wastes so in natural compounds as well. So the problem for obtaining hydrated calcium silicates having contact-condensation ability for structure formation becomes more and more actual one. This transition is considered as dependent principally on arrangement rate of substance particles which determined the level of its instability.

  1. 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.

  2. Influência da escória silicatada na acidez do solo e na produtividade de grãos do arroz de terras altas Influence of calcium silicate slag on soil acidity and upland rice grain yield

    Directory of Open Access Journals (Sweden)

    Morel Pereira Barbosa Filho

    2004-04-01

    Full Text Available Apesar dos elevados teores de SiO2 total geralmente encontrados nos solos brasileiros, o teor na solução do solo pode ser baixo, em conseqüência do processo de dessilicificação que ocorre durante a intemperização dos solos. A aplicação de escórias de processamento industrial, ricas em silicatos de cálcio, tem mostrado efeitos positivos quanto à ação corretiva da acidez do solo e ao fornecimento de Si às plantas acumuladoras desse elemento, com aumentos significativos de produtividade. Conduziu-se este trabalho com o seguinte objetivo: avaliar em dois anos de cultivo sucessivos a ação corretiva, a produtividade de grãos e a absorção de Si pelo arroz de terras altas. Foram aplicadas ao solo de cerrado classificado como latossolo vermelho distroférrico de cerrado seis doses (0, 2, 4, 6, 8 e 10 t ha-1 de uma escória silicatada com 20% de SiO2 total, proveniente do processo de fabricação de superfosfatos em forno elétrico. Utilizou-se o delineamento de blocos completos casualizados com cinco repetições. Foram detectados aumentos significativos de produtividade de grãos, teor e acumulação de Si na palha e da porcentagem de grãos cheios por panícula, nos dois anos de cultivo do arroz. Houve ação corretiva no solo das doses de escória, reduzindo a acidez e aumentando a disponibilidade de P, Si, Ca trocável e a porcentagem de saturação por bases. O nível crítico de Si na palha por ocasião da colheita, para obtenção de produtividade satisfatória de grãos, foi estabelecido em 2,25 g kg-1 de matéria seca.Despite the high SiO2 total content often found in Brazilian soils, the soluble silicon content in soil solution can be low due to weathering that occur in soils. The application of calcium silicate slags, under these conditions, has demonstrated positive effects in relation to correction of soil acidity, the supply of Si to plants that accumulate this element and significant yield increase. The objectives of

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

    Science.gov (United States)

    Guan, Wenqiang; Fan, Xuetong

    2010-03-01

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

  4. Design and characterization of calcium-free in-situ gel formulation based on sodium alginate and chitosan.

    Science.gov (United States)

    Belhadji, Linda; HadjSadok, Abdelkader; Moulai-Mostefa, Nadji

    2017-12-05

    The aim of this study was to prepare and evaluate calcium-free sustained release drug delivery systems, based on the in-situ gelation of oral suspensions containing chitosan, sodium alginate and Ranitidine as drug model. The combined effects of polymer concentrations and their interactions on the rheological characteristics of both gels and suspensions and, on the kinetics of drug release were evaluated by using a central composite face-centered design. Rheological analysis showed that suspensions were potentially stable, with a viscosity increased by 1000 times compared to that of water. In addition, the obtained gels were consistent; their storage modulus could reach values close to 50 kPa when alginate concentration was greater than 7.5 g/100 mL and chitosan was fixed to 0.5 g/100 mL. In these conditions gels should have a higher gastric residence time, in comparison to the standard gastric emptying time (∼2 h). Evaluation of the in-vitro release kinetics of Ranitidine showed that the association of the lowest concentration of chitosan (0.5 g/100 mL) with higher alginate concentrations generates sustained release kinetics profiles. The time corresponding to 63% of release was found close to 1.5 h, in which case the process is governed by Fickian diffusion. Finally, calcium-free alginate-chitosan based on the in-situ gelation of suspensions is advantageous as a drug delivery system for sustained-release.

  5. 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.

  6. 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.

  7. Role of voltage-gated sodium, potassium and calcium channels in the development of cocaine-associated cardiac arrhythmias

    Science.gov (United States)

    O'Leary, Michael E; Hancox, Jules C

    2010-01-01

    Cocaine is a highly active stimulant that alters dopamine metabolism in the central nervous system resulting in a feeling of euphoria that with time can lead to addictive behaviours. Cocaine has numerous deleterious effects in humans including seizures, vasoconstriction, ischaemia, increased heart rate and blood pressure, cardiac arrhythmias and sudden death. The cardiotoxic effects of cocaine are indirectly mediated by an increase in sympathomimetic stimulation to the heart and coronary vasculature and by a direct effect on the ion channels responsible for maintaining the electrical excitability of the heart. The direct and indirect effects of cocaine work in tandem to disrupt the co-ordinated electrical activity of the heart and have been associated with life-threatening cardiac arrhythmias. This review focuses on the direct effects of cocaine on cardiac ion channels, with particular focus on sodium, potassium and calcium channels, and on the contributions of these channels to cocaine-induced arrhythmias. Companion articles in this edition of the journal examine the epidemiology of cocaine use (Wood & Dargan [1]) and the treatment of cocaine-associated arrhythmias (Hoffmann [2]). PMID:20573078

  8. Calcium-activated SK channels control firing regularity by modulating sodium channel availability in midbrain dopamine neurons.

    Science.gov (United States)

    Iyer, Rajeshwari; Ungless, Mark A; Faisal, Aldo A

    2017-07-12

    Dopamine neurons in the substantia nigra pars compacta and ventral tegmental area regulate behaviours such as reward-related learning, and motor control. Dysfunction of these neurons is implicated in Schizophrenia, addiction to drugs, and Parkinson's disease. While some dopamine neurons fire single spikes at regular intervals, others fire irregular single spikes interspersed with bursts. Pharmacological inhibition of calcium-activated potassium (SK) channels increases the variability in their firing pattern, sometimes also increasing the number of spikes fired in bursts, indicating that SK channels play an important role in maintaining dopamine neuron firing regularity and burst firing. However, the exact mechanisms underlying these effects are still unclear. Here, we develop a biophysical model of a dopamine neuron incorporating ion channel stochasticity that enabled the analysis of availability of ion channels in multiple states during spiking. We find that decreased firing regularity is primarily due to a significant decrease in the AHP that in turn resulted in a reduction in the fraction of available voltage-gated sodium channels due to insufficient recovery from inactivation. Our model further predicts that inhibition of SK channels results in a depolarisation of action potential threshold along with an increase in its variability.

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

    Science.gov (United States)

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

    2008-07-01

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

  10. 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.

  11. Calcium and potassium silicates and the growth of Eucalyptus grandis seedlings Aplicação de silicatos de cálcio e de potássio e o crescimento de mudas de Eucalyptus grandis

    Directory of Open Access Journals (Sweden)

    Itamar Antonio Bognola

    2011-06-01

    Full Text Available

    The use of silicate is a practice that has been frequently adopted in annual crops, although few studies have been conducted in order to verify its efficiency in forest tree species. The main objective of this research was to evaluate the effect of calcium and potassium silicates in the growth of seedlings of Eucalyptus grandis. The experiment was conducted in a greenhouse, in Alambari county, State of São Paulo. A completely randomized experimental design was adopted, with eight treatments, three replications and 25 plants per plot, maintained at the field capacity moisture level. Seedlings were planted in plastic tubes using local substrate, basic fertilization and silicates. Diameter, height and fresh and dry biomass of the seedlings were determined 150 days after silicates treatments were applied. The use of silicates either in the substrate or through foliar application, in the production of eucalypt seedlings has proven to be inadequate when the substrate presents a balanced basic composition in terms of nutrients and pH.

    doi: 10.4336/2011.pfb.31.66.83

    O uso de silicato é uma prática que vem sendo adotada com frequência em culturas anuais, muito embora poucos trabalhos tenham sido realizados com intuito de verificar sua eficiência em espécies florestais arbóreas. O objetivo principal desta pesquisa foi avaliar o efeito da aplicação de silicatos de cálcio e de potássio no crescimento de mudas de Eucalyptus grandis. O experimento foi conduzido em casa de vegetação, no Município de Alambari, SP. O delineamento usado foi inteiramente ao acaso, com oito tratamentos, três repetições e 25 plantas por parcela, sendo mantidas na umidade de capacidade de campo. As mudas foram plantadas em tubetes de plástico, utilizando substrato local, com adubação básica e silicatos. Diâmetro de colo, altura e biomassa verde e seca das mudas foram determinados 150 dias após a

  12. Characterization and nutrient release from silicate rocks and influence on chemical changes in soil

    Directory of Open Access Journals (Sweden)

    Douglas Ramos Guelfi Silva

    2012-06-01

    Full Text Available The expansion of Brazilian agriculture has led to a heavy dependence on imported fertilizers to ensure the supply of the growing food demand. This fact has contributed to a growing interest in alternative nutrient sources, such as ground silicate rocks. It is necessary, however, to know the potential of nutrient release and changes these materials can cause in soils. The purpose of this study was to characterize six silicate rocks and evaluate their effects on the chemical properties of treated soil, assessed by chemical extractants after greenhouse incubation. The experimental design consisted of completely randomized plots, in a 3 x 6 factorial scheme, with four replications. The factors were potassium levels (0-control: without silicate rock application; 200; 400; 600 kg ha-1 of K2O, supplied as six silicate rock types (breccia, biotite schist, ultramafic rock, phlogopite schist and two types of mining waste. The chemical, physical and mineralogical properties of the alternative rock fertilizers were characterized. Treatments were applied to a dystrophic Red-Yellow Oxisol (Ferralsol, which was incubated for 100 days, at 70 % (w/w moisture in 3.7 kg/pots. The soil was evaluated for pH; calcium and magnesium were extracted with KCl 1 mol L-1; potassium, phosphorus and sodium by Mehlich 1; nickel, copper and zinc with DTPA; and the saturation of the cation exchange capacity was calculated for aluminum, calcium, magnesium, potassium, and sodium, and overall base saturation. The alternative fertilizers affected soil chemical properties. Ultramafic rock and Chapada mining byproduct (CMB were the silicate rocks that most influenced soil pH, while the mining byproduct (MB led to high K levels. Zinc availability was highest in the treatments with mining byproduct and Cu in soil fertilized with Chapada and mining byproduct.

  13. Increased sodium/calcium exchanger activity enhances beta-adrenergic-mediated increase in heart rate: Whole-heart study in a homozygous sodium/calcium exchanger overexpressor mouse model.

    Science.gov (United States)

    Kaese, Sven; Bögeholz, Nils; Pauls, Paul; Dechering, Dirk; Olligs, Jan; Kölker, Katharina; Badawi, Sascha; Frommeyer, Gerrit; Pott, Christian; Eckardt, Lars

    2017-08-01

    The cardiac sodium/calcium (Na(+)/Ca(2+)) exchanger (NCX) contributes to diastolic depolarization in cardiac pacemaker cells. Increased NCX activity has been found in heart failure and atrial fibrillation. The influence of increased NCX activity on resting heart rate, beta-adrenergic-mediated increase in heart rate, and cardiac conduction properties is unknown. The purpose of this study was to investigate the influence of NCX overexpression in a homozygous transgenic whole-heart mouse model (NCX-OE) on sinus and AV nodal function. Langendorff-perfused, beating whole hearts of NCX-OE and the corresponding wild-type (WT) were studied ± isoproterenol (ISO; 0.2 μM). Epicardial ECG, AV nodal Wenckebach cycle length (AVN-WCL), and retrograde AVN-WCL were obtained. At baseline, basal heart rate was unaltered between NCX-OE and WT (WT: cycle length [CL] 177.6 ± 40.0 ms, no. of hearts [n] = 20; NCX-OE: CL 185.9 ± 30.5 ms, n = 18; P = .21). In the presence of ISO, NCX-OE exhibited a significantly higher heart rate compared to WT (WT: CL 133.4 ± 13.4 ms, n = 20; NCX-OE: CL 117.7 ± 14.2 ms, n = 18; P heart rate. Mechanistically, increased NCX inward mode activity may promote acceleration of diastolic depolarization in sinus nodal pacemaker cells, thus enhancing chronotropy in NCX-OE. These findings suggest a novel potential therapeutic target for heart rate control in the presence of increased NCX activity, such as heart failure. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  14. Oral calcium supplementation ambulatory blood pressure and relation to changes in intracellular ions and sodium-hydrogen exchange.

    Science.gov (United States)

    Pikilidou, Maria I; Befani, Christina D; Sarafidis, Pantelis A; Nilsson, Peter M; Koliakos, George G; Tziolas, Ioannis M; Kazakos, Kiriakos A; Yovos, John G; Lasaridis, Anastasios N

    2009-12-01

    Calcium (Ca2+) supplementation has been shown paradoxically to reduce intracellular Ca2+ and induce vascular relaxation. The aim of the study was to assess 24-h blood pressure (BP) change after Ca2+ supplementation and to investigate its relation to changes in intracellular ions and the activity of the first isoform of sodium-hydrogen exchange (NHE-1) in subjects with hypertension and type 2 diabetes. This parallel, randomized controlled, single-blinded trial, consisted of 31 patients with type 2 diabetes, and hypertension who were allocated to receive 1,500 mg of Ca2+ per day (n = 15) or no treatment (n = 16) for 8 weeks. In the Ca2+ group a decrease of 1.7 +/- 2.7 mm Hg (mean +/- SE) P = 0.52 for mean 24-h systolic BP (SBP) and 2.1 +/- 1.5 mm Hg, P = 0.19 for mean 24-h diastolic BP (DBP) was recorded. Whereas in the control group an increase of 1.4 +/- 2.7 mm Hg, P = 0.59 for mean 24-h SBP and 1.2 +/- 2.8 mm Hg, P = 0.83 for mean 24-h DBP was observed. Intraplatelet Ca2+ decreased whereas intraplatelet magnesium (Mg2+) and erythrocyte K+ increased in the intervention group. Change in mean 24-h SBP in the pooled group correlated with both change in intraplatelet Ca2+ (r = 0.49, P < 0.05) and NHE-1 activity (r = 0.6, P < 0.001). The contribution of intraplatelet Ca2+ was attenuated when both parameters were entered in a multivariate regression model. The present study shows a weak, statistically nonsignificant trend towards association of Ca2+ supplementation on 24-h BP in hypertensive subjects with type 2 diabetes. However, our results indicated an interrelation of [Ca2+]i levels and NHE-1 activity on BP in patients with hypertension and type 2 diabetes.

  15. Preparation of hydroxyapatite/collagen injectable bone paste with an anti-washout property utilizing sodium alginate. Part 1: influences of excess supplementation of calcium compounds.

    Science.gov (United States)

    Sato, Taira; Kikuchi, Masanori; Aizawa, Mamoru

    2017-03-01

    The anti-washout property, viscosity, and cytocompatibility to an osteoblastic cell line, MG-63, of anti-washout pastes were investigated. Mixing a hydroxyapatite/collagen bone-like nanocomposite (HAp/Col), an aqueous solution of sodium alginate (Na-Alg), which is a paste hardening and lubricant agent, and supplementation of calcium carbonate or calcium citrate (Ca-Cit) as a calcium resource for the hardening reaction realized an injectable bone paste. Adding Ca-Cit at a concentration greater than eight times the Ca(2+) ion concentration to Na-Alg improved the anti-washout property. Although the viscosity test indicated a gradual increase in the paste viscosity as the calcium compounds increased, pastes with excess supplementation of calcium compounds exhibited injectability through a syringe with a 1.8 mm inner diameter, realizing an injectable bone filler. Furthermore, the anti-washout pastes with Ca-Cit had almost the same cell proliferation rate as that of the HAp/Col dense body. Therefore, HAp/Col injectable anti-washout pastes composed of the HAp/Col, Na-Alg, and Ca-Cit are potential candidates for bioresorbable bone filler pastes.

  16. Fresh properties and compressive strength of high calcium alkali activated fly ash mortar

    Directory of Open Access Journals (Sweden)

    Eslam Gomaa

    2017-10-01

    Full Text Available This paper reports the fresh properties and compressive strength of high calcium alkali-activated fly ash (AAFA mortar. Two different sources of class C fly ash, with different chemical compositions were used to prepare alkali-activated mortar mixtures. Four different sodium silicate to sodium hydroxide (SS/SH ratios of 0.5, 1.0, 1.5, and 2.5 were used as alkaline activators with a constant sodium hydroxide concentration of 10 M. Two curing regimes were also applied, oven curing at 70 °C for 24 h, and ambient curing at 23 ± 2 °C. The rest time, i.e., the time between casting the mortar cubes and starting the oven curing was 2 h. The results revealed that the setting time, and workability of mortar decreased with increasing the alkali to fly ash ratio, and decreasing the water to fly ash ratio. The optimum sodium silicate to sodium hydroxide ratio was 1.0, which showed the highest compressive strength and setting time. An increase of sodium silicate to sodium hydroxide ratio to 2.5 led to a significant reduction in the setting time, and workability of mortar. The 7-day compressive strength of the mortar approached 20.80 MPa for ambient cured regime and 41.10 for oven cured regime.

  17. Understanding silicate hydration from quantitative analyses of hydrating tricalcium silicates

    Science.gov (United States)

    Pustovgar, Elizaveta; Sangodkar, Rahul P.; Andreev, Andrey S.; Palacios, Marta; Chmelka, Bradley F.; Flatt, Robert J.; d'Espinose de Lacaillerie, Jean-Baptiste

    2016-01-01

    Silicate hydration is prevalent in natural and technological processes, such as, mineral weathering, glass alteration, zeolite syntheses and cement hydration. Tricalcium silicate (Ca3SiO5), the main constituent of Portland cement, is amongst the most reactive silicates in water. Despite its widespread industrial use, the reaction of Ca3SiO5 with water to form calcium-silicate-hydrates (C-S-H) still hosts many open questions. Here, we show that solid-state nuclear magnetic resonance measurements of 29Si-enriched triclinic Ca3SiO5 enable the quantitative monitoring of the hydration process in terms of transient local molecular composition, extent of silicate hydration and polymerization. This provides insights on the relative influence of surface hydroxylation and hydrate precipitation on the hydration rate. When the rate drops, the amount of hydroxylated Ca3SiO5 decreases, thus demonstrating the partial passivation of the surface during the deceleration stage. Moreover, the relative quantities of monomers, dimers, pentamers and octamers in the C-S-H structure are measured. PMID:27009966

  18. Avaliação de cultivares de alface adubadas com silicato de cálcio em casa-de-vegetação Evaluation of lettuce cultivars fertilized with calcium silicate in greenhouse

    Directory of Open Access Journals (Sweden)

    Regina Lúcia Félix Ferreira

    2010-10-01

    Full Text Available O experimento foi conduzido no Departamento de Ciência do Solo da Universidade Federal de Lavras - UFLA, no período de junho a agosto de 2002. Objetivou-se avaliar a produtividade, o estado nutricional e a qualidade (classe de tamanho de cultivares de alface cultivadas com doses de silicato de cálcio em vasos sob casa-de-vegetação. O delineamento experimental foi em blocos casualizados, com quatro repetições, com 1 planta/vaso, em esquema fatorial 3 x 4 + 3, sendo três cultivares de alface (Raider, Regina e Vera e quatro doses de silicato de cálcio (0, 410, 1,000 e 2,000 mg dm-3; os tratamentos adicionais foram compostos pela aplicação de 820 mg dm-3 de carbonato de cálcio, para as três cultivares. O estado nutricional das plantas de alface foi avaliado pelo Sistema Integrado de Diagnose e Recomendação (DRIS. A aplicação da fonte silicato de cálcio não aumentou o crescimento das plantas e não aumentou o teor dos nutrientes nas plantas de alface, mas melhorou a nutrição das plantas para Si e aumentou a porcentagem de plantas sadias. A aplicação também aumentou a concentração de Mn, devido ao alto conteúdo de Mn no fertilizante aplicado (Silifértil®. As três variedades de alface comportaram-se como plantas não acumuladoras de Si.The experiment was carried out at the Department of Soil Sciences of the Universidade Federal de Lavras - UFLA, from June to August 2002, with the objective to evaluate the productivity, the nutritional state and the quality (size class of lettuce cultivars grown with calcium silicate in greenhouse. The experimental design was disposed in blocks with four replicates, in factorial arrangement with additional treatments: 3 x 4 +3, composed by three lettuce cultivars: Raider (group crisphead lettuce; Regina (group butterhead lettuce and Vera (group looseleaf lettuce and four calcium silicate rates (0, 410, 1.000 and 2.000 mg dm-3, additional treatments were composed of the application of

  19. Characterization of silicates and calcium carbonates applied to high-dose dosimetry; Caracterizacao de silicatos e carbonatos de calcio aplicados a dosimetria de doses altas

    Energy Technology Data Exchange (ETDEWEB)

    Vila, Gustavo Barreto

    2012-07-01

    The predominant isomorphous form in the biominerals studied in this work (oyster shell, coral, mother of pearl and shell) was aragonite. The appearance of the calcite phase occurred at 500 deg C at a heating rate of 10 deg {sup C}/s for all samples except for the coral sample, which was 400 deg C, independent of the heating rate. The most abundant element in the biominerals samples was Ca in the CaO form, and in the silicates (tremolite, diopside and rhodonite) Si in the SiO form. The most common trace element observed in the biominerals samples was Fe. The analyses of electron paramagnetic resonance showed lines of Mn{sup 2+} in the coral and mother-of-pearl samples before irradiation. In the case of the irradiated samples, the defects found were CO{sub 2}{sup -}, CO{sub 3}{sup 3-}, CO{sub 3}{sup -} and SO{sub 2}{sup -}, in the g range between 2.0010 and 2.0062. In the analyses by optical absorption of biominerals, transitions due to the presence of Mn in the samples were found. A thermoluminescent (TL) peak at approximately 140 deg C was found for the biominerals and at 180 deg C for silicates, which intensity depends directly on the dose. For samples exposed to different types of radiation, the TL peak occurred at lower temperatures. From the dose-response curves obtained for these materials, it was possible to determine a linear range for which their application in high dose dosimetry becomes possible. Taking into account the radiation type, among biominerals and silicates, the lowest detectable dose (40mGy) to gamma radiation was achieved for oyster shell samples using the measuring technique of optically stimulated luminescence (OSL). Using beta radiation, for diopside and tremolite samples the lowest detectable dose of 60mGy was obtained. For all samples, using the TL, OSL and thermally stimulated exoelectron emission (TSEE) techniques in alpha, beta and gamma radiation beans a good response reproducibility was obtained. Therefore, the samples characterized

  20. Inhibition of collagen synthesis by select calcium and sodium channel blockers can be mitigated by ascorbic acid and ascorbyl palmitate.

    Science.gov (United States)

    Ivanov, Vadim; Ivanova, Svetlana; Kalinovsky, Tatiana; Niedzwiecki, Aleksandra; Rath, Matthias

    2016-01-01

    Calcium, sodium and potassium channel blockers are widely prescribed medications for a variety of health problems, most frequently for cardiac arrhythmias, hypertension, angina pectoris and other disorders. However, chronic application of channel blockers is associated with numerous side effects, including worsening cardiac pathology. For example, nifedipine, a calcium-channel blocker was found to be associated with increased mortality and increased risk for myocardial infarction. In addition to the side effects mentioned above by different channel blockers, these drugs can cause arterial wall damage, thereby contributing to vascular wall structure destabilization and promoting events facilitating rupture of plaques. Collagen synthesis is regulated by ascorbic acid, which is also essential for its optimum structure as a cofactor in lysine and proline hydroxylation, a precondition for optimum crosslinking of collagen and elastin. Therefore, the main objective in this study was to evaluate effects of various types of channel blockers on intracellular accumulation and cellular functions of ascorbate, specifically in relation to formation and extracellular deposition of major collagen types relevant for vascular function. Effects of select Na- and Ca- channel blockers on collagen synthesis and deposition were evaluated in cultured human dermal fibroblasts and aortic smooth muscle cells by immunoassay. All channel blockers tested demonstrated inhibitory effects on collagen type I deposition to the ECM by fibroblasts, each to a different degree. Ascorbic acid significantly increased collagen I ECM deposition. Nifedipine (50 µM), a representative of channel blockers tested, significantly reduced ascorbic acid and ascorbyl palmitate-dependent ECM deposition of collagen type l and collagen type lV by cultured aortic smooth muscle cells. In addition, nifedipine (50 µM) significantly reduced ascorbate-dependent collagen type l and type lV synthesis by cultured aortic smooth

  1. Addition of 1, 2 and 3% in mass of sodium alginate in calcium phosphate cement; Adicao de alginato de sodio a cimento de fosfato de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, W.T.; Fernandes, J.M.; Vieira, R.S.; Thurmer, M.B.; Santos, L.A., E-mail: trajano@ufrgs.br [Universidade Federal do Rio Grande do Sul (LABIOMAT/UFRS), RS (Brazil)

    2011-07-01

    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)

  2. Alleviating negative effects of irrigation-water salinity on growth and vase life of gerbera by foliar spray of calcium chloride and potassium silicate

    OpenAIRE

    A. Mohammadi Torkashvand

    2015-01-01

    The required water for greenhouses in Kishestan, Soume-e-Sara town, Guilan province, Iran, is mainly provided by underground resources that have inappropriate quality. One way to reduce the impact of salinity an plant growth is proper nutrition. This greenhouse research was conducted to evaluate the effect of water salinity and foliar spray of calcium (Ca) and silicon (Si) on growth and vase life of gerbera in a factorial experiment based on compeletly randomized design with two factors. The ...

  3. Workability and strength of coarse high calcium fly ash geopolymer

    Energy Technology Data Exchange (ETDEWEB)

    P. Chindaprasirt; T. Chareerat; V. Sirivivatnanon [Khon Kaen University, Khon Kaen (Thailand). Department of Civil Engineering

    2007-03-15

    In this paper, the basic properties viz., workability and strength of geopolymer mortar made from coarse lignite high calcium fly ash were investigated. The geopolymer was activated with sodium hydroxide (NaOH), sodium silicate and heat. The results revealed that the workable flow of geopolymer mortar was in the range of 110 {+-}5%-135 {+-}5% and was dependent on the ratio by mass of sodium silicate to NaOH and the concentration of NaOH. The obtained compressive strength was in the range of 10-65 MPa. The optimum sodium silicate to NaOH ratio to produce high strength geopolymer was 0.67-1.0. The concentration variation of NaOH between 10 M and 20 M was found to have a small effect on the strength. The geopolymer samples with high strength were obtained with the following practices: the delay time after moulding and before subjecting the sample to heat was 1 h and the optimum curing temperature in the oven was 75{sup o}C with the curing duration of not less than two days.

  4. The influence of Al{sub 2}O{sub 3}, MgO and ZnO on the crystallization characteristics and properties of lithium calcium silicate glasses and glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Salman, S.M. [Glass Research Department, National Research Centre, El-Behoos St., Dokki, Cairo (Egypt)], E-mail: saadmoghazy@hotmail.com; Darwish, H.; Mahdy, E.A. [Glass Research Department, National Research Centre, El-Behoos St., Dokki, Cairo (Egypt)

    2008-12-20

    The crystallization characteristics of glasses based on the Li{sub 2}O-CaO-SiO{sub 2} eutectic (954 {+-} 4 deg. C) system containing Al{sub 2}O{sub 3}, MgO and ZnO has been investigated by differential thermal analysis (DTA), X-ray diffraction analysis (XRD), and scanning electron microscopy (SEM). The partial replacement of Li{sub 2}O by Al{sub 2}O{sub 3} and CaO by MgO or ZnO in the studied glass-ceramics led to the development of different crystalline phase assemblages, including lithium meta- and di-silicates, lithium calcium silicates, {alpha}-quartz, diopside, clinoenstatite, wollastonite, {beta}-eucryptite ss, {beta}-spodumene, {alpha}-tridymite, lithium zinc orthosilicate, hardystonite and willemite using various heat-treatment processes. The dilatometric thermal expansion of the glasses and their corresponding glass-ceramics were determined. A wide range of thermal expansion coefficient values were obtained for the investigated glasses and their corresponding crystalline products. The thermal expansion coefficients of the investigated glasses were decreased by Al{sub 2}O{sub 3}, MgO or ZnO additions. The {alpha}-values of the investigated glasses were ranged from (+18) to (+108) x 10{sup -7} K{sup -1} (25-300 deg. C), while those of the glass-ceramics were (+3) to (+135) x 10{sup -7} K{sup -1} (25-700 deg. C). The chemical durability of the glass-ceramics, towards the attack of 0.1N HCl solution, was markedly improved by Al{sub 2}O{sub 3} with MgO replacements. The composition containing 11.5 mol% Al{sub 2}O{sub 3} and 6.00 mol% MgO exhibited low thermal expansion values and good chemical durability.

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

    Science.gov (United States)

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

    2011-12-01

    Blends of calcium, magnesium and potassium chloride were used to partially replace sodium chloride (50-75%) in reduced-fat mortadella formulations. The presence of calcium chloride reduced the emulsion stability, cooking yield, elasticity and cohesiveness and increased hardness; however, it yielded the best sensory acceptance when 50% NaCl was replaced by 25% CaCl(2) and 25% KCl. There was no effect of the salt substitutes on mortadella color, appearance and aroma. All salt combinations studied showed stable lipid oxidation during its shelf life. The use of a blend with 1% NaCl, 0.5% KCl and 0.5% MgCl(2) resulted in the best emulsion stability, but the worst scores for flavor. This study suggests that it is possible to reduce the sodium chloride concentration by 50% in reduced-fat mortadella using the studied salt combinations with necessary adjustments to optimize the sensory properties (MgCl(2) 25%; KCl 25%) or emulsion stability (CaCl(2) 25%; KCl 25%). Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Populus euphratica displays apoplastic sodium accumulation, osmotic adjustment by decreases in calcium and soluble carbohydrates, and develops leaf succulence under salt stress.

    Science.gov (United States)

    Ottow, Eric A; Brinker, Monika; Teichmann, Thomas; Fritz, Eberhard; Kaiser, Werner; Brosché, Mikael; Kangasjärvi, Jaakko; Jiang, Xiangning; Polle, Andrea

    2005-12-01

    Populus euphratica Olivier is known to exist in saline and arid environments. In this study we investigated the physiological mechanisms enabling this species to cope with stress caused by salinity. Acclimation to increasing Na+ concentrations required adjustments of the osmotic pressure of leaves, which were achieved by accumulation of Na+ and compensatory decreases in calcium and soluble carbohydrates. The counterbalance of Na+/Ca2+ was also observed in mature leaves from field-grown P. euphratica trees exposed to an environmental gradient of increasing salinity. X-ray microanalysis showed that a primary strategy to protect the cytosol against sodium toxicity was apoplastic but not vacuolar salt accumulation. The ability to cope with salinity also included maintenance of cytosolic potassium concentrations and development of leaf succulence due to an increase in cell number and cell volume leading to sodium dilution. Decreases in apoplastic and vacuolar Ca2+ combined with suppression of calcineurin B-like protein transcripts suggest that Na+ adaptation required suppression of calcium-related signaling pathways. Significant increases in galactinol synthase and alternative oxidase after salt shock and salt adaptation point to shifts in carbohydrate metabolism and suppression of reactive oxygen species in mitochondria under salt stress.

  7. Populus euphratica Displays Apoplastic Sodium Accumulation, Osmotic Adjustment by Decreases in Calcium and Soluble Carbohydrates, and Develops Leaf Succulence under Salt Stress1[W

    Science.gov (United States)

    Ottow, Eric A.; Brinker, Monika; Teichmann, Thomas; Fritz, Eberhard; Kaiser, Werner; Brosché, Mikael; Kangasjärvi, Jaakko; Jiang, Xiangning; Polle, Andrea

    2005-01-01

    Populus euphratica Olivier is known to exist in saline and arid environments. In this study we investigated the physiological mechanisms enabling this species to cope with stress caused by salinity. Acclimation to increasing Na+ concentrations required adjustments of the osmotic pressure of leaves, which were achieved by accumulation of Na+ and compensatory decreases in calcium and soluble carbohydrates. The counterbalance of Na+/Ca2+ was also observed in mature leaves from field-grown P. euphratica trees exposed to an environmental gradient of increasing salinity. X-ray microanalysis showed that a primary strategy to protect the cytosol against sodium toxicity was apoplastic but not vacuolar salt accumulation. The ability to cope with salinity also included maintenance of cytosolic potassium concentrations and development of leaf succulence due to an increase in cell number and cell volume leading to sodium dilution. Decreases in apoplastic and vacuolar Ca2+ combined with suppression of calcineurin B-like protein transcripts suggest that Na+ adaptation required suppression of calcium-related signaling pathways. Significant increases in galactinol synthase and alternative oxidase after salt shock and salt adaptation point to shifts in carbohydrate metabolism and suppression of reactive oxygen species in mitochondria under salt stress. PMID:16299175

  8. GROWTH OF PEACH PALM (Bactris gasipaes H.B.K. SEEDLINGS AS A FUNCTION OF RELATIONSHIPS OF POTASSIUM WITH CALCIUM AND WITH SODIUM, IN NUTRITIVE SOLUTION

    Directory of Open Access Journals (Sweden)

    Antonio Rodrigues Fernandes

    2001-01-01

    Full Text Available The experiment was carried out in nutrient solution, under greenhouse conditions at the Soil Science Department - Lavras Federal University, Minas Gerais state, Brazil, to evaluate the effect of different relationships of potassium with calcium and with sodium, upon growth of peach palm (Bactris gasipaes H.B.K. seedlings. The experimental design was in randomized blocks, with ninetreatments and four replications. The treatments consisted of the foolowing K/Ca relationships: 0.0/3.0; 1.0/2.5; 2.0/2.0; 3.0/1.5; 4.0/1.0; 5.0/0.5; and 6.0/0.0 mmol L-1 and two additional treatments with variation in the concentration of sodium constituting the K/Na relationships of: 2.0/0.0 and 1.0/2.0. In this last one part of the potassium was substituted by sodium. The experimental units were constituted by one vase containing one plant. Height, perimeter at the stem level, leaf area and dry matter of leaves, stipes and roots were evaluated. The K/Ca relationships of 2.0/2.0 and 3.0/1.5, were the ones that provided larger medium values for leaf area and dry matter of parts of the plant, and this last one, favored more the growth of the plants. In the treatments without sodium or with the increase concentration of sodium all variables evaluated were negatively affected. Symptoms of deficiency of potassium in the leaves, followed by drastic reduction in growth appeared in the plants submitted to relationships where it was absent or with 1 mmol L-1.

  9. Effect of insecticidal fusion proteins containing spider toxins targeting sodium and calcium ion channels on pyrethroid-resistant strains of peach-potato aphid (Myzus persicae).

    Science.gov (United States)

    Yang, Sheng; Fitches, Elaine; Pyati, Prashant; Gatehouse, John A

    2015-07-01

    The recombinant fusion proteins Pl1a/GNA and Hv1a/GNA contain the spider venom peptides δ-amaurobitoxin-PI1a or ω-hexatoxin-Hv1a respectively, linked to snowdrop lectin (GNA). Pl1a targets receptor site 4 of insect voltage-gated sodium channels (NaCh), while Hv1a targets voltage-gated calcium channels. Insecticide-resistant strains of peach-potato aphid (Myzus persicae) contain mutations in NaCh. The pyrethroid-resistant kdr (794J) and super-kdr (UKO) strains contain mutations at residues L1014 and M918 in the channel α-subunit respectively, while the kdr + super-kdr strain (4824J), insensitive to pyrethroids, contains mutations at both L1014 and M918. Pl1a/GNA and Hv1a/GNA fusion proteins have estimated LC50 values of 0.35 and 0.19 mg mL(-1) when fed to wild-type M. persicae. For insecticide-resistant aphids, LC50 for the Pl1a/GNA fusion protein increased by 2-6-fold, correlating with pyrethroid resistance (wild type < kdr < super-kdr < kdr + super-kdr strains). In contrast, LC50 for the Hv1a/GNA fusion protein showed limited correlation with pyrethroid resistance. Mutations in the sodium channel in pyrethroid-resistant aphids also protect against a fusion protein containing a sodium-channel-specific toxin, in spite of differences in ligand-channel interactions, but do not confer resistance to a fusion protein targeting calcium channels. The use of fusion proteins with differing targets could play a role in managing pesticide resistance. © 2014 Society of Chemical Industry.

  10. The impact of selected preparations of trace elements - magnesium, potassium, calcium, and zinc on the release of diclofenac sodium from enteric coated tablets and from sustained release capsules.

    Science.gov (United States)

    Biernat, Paweł; Musiał, Witold; Gosławska, Dorota; Pluta, Janusz

    2014-01-01

    In an aging society, many patients require long-term treatment. This fact is associated clearly with the simultaneous occurrence of lifestyle diseases such as hypertension, diabetes, and even osteoarthritis. Concomitant medications, which are a common practice, pose a major threat of an interaction between these drugs. Very popular now "fast way of life" that makes people have less and less time to prepare well-balanced meals of high nutritional value. The result of this lifestyle is an increased need for supplementation preparations necessary vitamins and minerals. Given the wide availability of dietary supplements (shops, kiosks, petrol stations) raises the question about the possibility of an interaction between the uncontrolled intake of dietary supplements and medications received in the most common diseases of civilization. The aim of this study was to investigate the effect of the most important minerals (magnesium, potassium, calcium, zinc) contained in the popular nutritional supplements, the release also often used as an anti-pain, anti-inflammatory, diclofenac sodium from the different formulations. Among the many as sodium diclofenac selected two most common: film-coated tablets and sustained release capsules. The study showed a significant effect of minerals on the release of diclofenac sodium and differences that impact, depending on the test form of the drug.

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

    Science.gov (United States)

    Moezizadeh, Maryam; Alimi, Azar

    2014-01-01

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

  12. [Efficacy of sodium hydroxide at 2.5 %, chlorhexidine gluconate at 0.5 % and calcium hydroxide against Candida albicans].

    Science.gov (United States)

    Ndiaye, D; Diongue, K; Bane, K; Seck, A; Niang, S O; Lèye Benoist, F; Ndiaye, D; Touré, B

    2016-12-01

    Endodontic flora is dominated in the apical part of the channels by strict anaerobic and some facultative anaerobic bacteria but also by Candida yeasts, especially Candida albicans species that are involved in the maintenance and persistence of endodontic infections. Their elimination of the canal system in practice by chemo-mechanical methods of disinfection is not always guaranteed. Thus, this in vitro study was performed to determine the sensitivity of C. albicans with sodium hypochlorite (NaOCl) dosed at 2.5 %, the chlorhexidine digluconate 0.5 % and calcium hydroxide used in inter-session medication. The diffusion method was used initially to test the sensitivity of C. albicans strains with the above products. Then a dilution technique has allowed us to determine the minimum inhibitory concentration of these active products on C. albicans. Strains from infected pulp teeth of patients showed a sensitivity of C. albicans to sodium hypochlorite to a minimum inhibitory concentration less than 70μg/mL and 30μg/mL for chlorhexidine. This study demonstrated a sensitivity of C. albicans to sodium hypochlorite and chlorhexidine. Copyright © 2016. Published by Elsevier Masson SAS.

  13. Effect of calcium and magnesium silicate on the growth of the castor oil plant subjected to salinity levels
    Efeito de silicato de cálcio e magnésio sobre o crescimento de plantas de mamoneira submetidas a níveis de salinidade

    OpenAIRE

    José Félix Brito Neto; Napoleão de Esberard Macêdo Beltrão; João Paulo Gonsiorkiewicz Rigon; Silvia Capuani

    2012-01-01

    Salt stress decreases the osmotic potential of soil solution causing water stress, causing toxic effects in the plants resulting in injuries on the metabolism and nutritional disorders, thus compromising the plant growth, resulting in lower production. The calcium silicate and magnesium can perform the same function as limestone, besides providing silicon to plants, may also contribute to the resistance of plants to salt stress. Thus, the objective of this study was to evaluate the effect of ...

  14. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    OpenAIRE

    Andrea Marisa Pereyra; Carlos Alberto Giudice

    2007-01-01

    The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia) impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses ...

  15. Hydrothermal Synthesis of Dicalcium Silicate Based Cement

    Science.gov (United States)

    Dutta, N.; Chatterjee, A.

    2017-06-01

    It is imperative to develop low energy alternative binders considering the large amounts of energy consumed as well as carbon dioxide emissions involved in the manufacturing of ordinary Portland cement. This study is on the synthesis of a dicalcium silicate based binder using a low temperature hydrothermal route.The process consists of synthesizing an intermediate product consisting of a calcium silicate hydrate phase with a Ca:Si ratio of 2:1 and further thermal treatment to produce the β-Ca2SiO4 (C2S) phase.Effect of various synthesis parameters like water to solid ratio, dwell time and temperature on the formation of the desired calcium silicate hydrate phase is reported along with effect of heating conditions for formation of the β-C2S phase. Around 77.45% of β-C2S phase was synthesized by thermal treatment of the intermediate phase at 820°C.

  16. Structure of short-range-ordered iron(III)-precipitates formed by iron(II) oxidation in water containing phosphate, silicate, and calcium

    Science.gov (United States)

    Voegelin, A.; Frommer, J.; Vantelon, D.; Kaegi, R.; Hug, S. J.

    2009-04-01

    The oxidation of Fe(II) in water leads to the formation of Fe(III)-precipitates that strongly affect the fate of nutrients and contaminants in natural and engineered systems. Examples include the cycling of As in rice fields irrigated with As-rich groundwater or the treatment of drinking water for As removal. Knowledge of the types of Fe(III)-precipitates forming in such systems is essential for the quantitative modeling of nutrient and contaminant dynamics and for the optimization of water purification techniques on the basis of a mechanistic understanding of the relevant biogeochemical processes. In this study, we investigated the local coordination of Fe, P, and Ca in Fe(III)-precipitates formed by aeration of synthetic Fe(II)-containing groundwater with variable composition (pH 7, 2-30 mg/L Fe(II), 2-20 mg/L phosphate-P, 2-20 mg/L silicate-Si, 8 mM Na-bicarbonate or 2.5 mM Ca-&1.5 mM Mg-bicarbonate). After 4 hours of oxidation, Fe(III)-precipitates were collected on 0.2 µm nylon filters and dried. The precipitates were analyzed by Fe K-edge EXAFS (XAS beamline, ANKA, Germany) and by P and Ca K-edge XANES spectroscopy (LUCIA beamline, SLS, Switzerland). The Fe K-edge EXAFS spectra indicated that local Fe coordination in the precipitates systematically shifted with water composition. As long as water contained P, mainly short-range-ordered Fe(III)-phosphate formed (with molar P/Fe ~0.5). In the absence of P, Fe(III) precipitated as hydrous ferric oxide at high Si/Fe>0.5, as ferrihydrite at intermediate Si/Fe, and mainly as lepidocrocite at Si/Fepatterns. The P K-edge XANES spectra revealed that phosphate was bound to both Fe as well as Ca (if present). The Ca K-edge XANES spectra showed that the mode of Ca uptake by the Fe(III)-precipitates shifted from mainly adsorption at high Fe/P to coprecipitation at low Fe/P ratio. Despite oversaturation, neither calcite nor hydroxyapatite formed to a significant extent. The results from this study indicated that

  17. Extrinsic tooth stain removal efficacy of a sodium bicarbonate dual-phase dentifrice containing calcium and phosphate in a six-week clinical trial.

    Science.gov (United States)

    Putt, Mark S; Milleman, Jeffery L; Ghassemi, Annahita

    2004-01-01

    The objective of this clinical investigation was to evaluate the effectiveness in removing existing extrinsic tooth stains of a sodium bicarbonate (baking soda), dual-phase dentifrice containing calcium and phosphate (Test Dentifrice), when compared to a commercial hydrated silica dentifrice (Control Dentifrice), during a six-week period of normal, unsupervised use. This investigation was a double-blind comparison of two equivalent, parallel groups of subjects assigned to use different dentifrices for six weeks. A total of 108 adult male and female subjects qualified for the trial based on the presence of existing extrinsic tooth stains and other inclusion/exclusion criteria. The two groups were balanced for gender, tobacco use, and extrinsic tooth stain scores, and randomly assigned the Test or Control dentifrices. All subjects were instructed to brush their teeth twice daily using only the dentifrice and toothbrush provided, and to refrain from using any other oral hygiene products for the duration of the study. Although product usage was unsupervised after the baseline visit, subjects maintained a treatment diary, and product consumption was monitored to estimate compliance. Oral soft and hard tissue and extrinsic stain assessments (Modified Lobene Stain Index) for each subject were conducted at baseline and after two, four, and six weeks of product use. A total of 107 subjects complied with the protocol and completed the six-week study. Compared to baseline, at the two-, four-, and six-week examinations the Test Dentifrice group had statistically significant reductions in extrinsic tooth stain. In contrast, the Control Dentifrice group did not attain significant reductions from baseline at any of the exams. At both the four-week and six-week examinations, the Test Dentifrice group had significantly lower levels of extrinsic tooth stain than the Control Dentifrice group. A sodium bicarbonate, dual-phase dentifrice containing calcium and phosphate demonstrated

  18. People with the major alleles of ATP2B1 rs17249754 increases the risk of hypertension in high ratio of sodium and potassium, and low calcium intakes.

    Science.gov (United States)

    Daily, J W; Kim, B C; Liu, M; Park, S

    2017-12-01

    It is important to understand what genetic risk factors lead to hypertension and how genotype-specific dietary and lifestyle modification can mitigate the risk of developing hypertension. The ATP2B1 rs17249754 gene, which encodes a calcium pump expressed in vascular smooth muscle was identified as having variants that conferred higher or lower risk of hypertension-with the major allele carriers being increased at risk. However, the effects of dietary intakes on risk of hypertension among carriers of the different alleles have not been fully elucidated. Therefore, we evaluated ATP2B1 rs17249754 and its interaction with dietary intakes of sodium (Na), potassium (K) and calcium (Ca) on the risk of developing hypertension using the Ansan/Ansung (n=8842) and City-Rural (n=5512) cohorts from the Korean Genome and Epidemiology Study. Carriers of the major allele of ATP2B1 rs17249754 were at greater risk of developing hypertension and high Na intake and low Ca increased the risk more in major allele than among minor allele carriers. High potassium intake was more protective against hypertension in the subjects expressing minor alleles and a low Na/K intake ratio was the most consistently beneficial to the subjects expressing the minor allele. When controlling for Na and K, low Ca intake was associated with a substantially higher risk for high systolic blood pressure in the major allele carriers compared with minor allele, suggesting good calcium status is especially important for the major allele carriers. In conclusion, people with the major allele of ATP2B1 rs17249754 are susceptible to hypertension especially in low intake of Ca and high ratio of Na and K.

  19. Silicate grout curtains behaviour for the protection of coastal aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Elektorowicz, M.; Chifrina, R.; Hesnawi, R. [Concordia Univ., Montreal, Quebec (Canada)

    1997-12-31

    Tests were performed to evaluate the behaviour of silicate grout with different reagents (ethylacetate - formamide SA and calcium chloride SC) in pure silica sand and natural soils from coastal areas containing organic matter, clayey soil and silica sand. The grouted specimens were tested with simulated fresh and salt water. The setting process during chemical grouting in the soil and sand was studied. The grouting of soil and sand with SA caused a transfer to the environment of some compounds: sodium formate, sodium acetate, ammonia and part of the initial ethylacetate and formamide. This process had a tendency to decrease for approximately 4 months. The stability of specimens was low. The grouting of soil and sand with SC caused no significant contamination of the environment. The increase of pH of environmental water was even less than with SA grouting. Also, the stability of specimens is higher in comparison with SA grouting. Salt water protected the specimens grouted with SA and SC from destruction and prevented contamination.

  20. Modulation of Low-Voltage-Activated Inward Current Permeable to Sodium and Calcium by DARPP-32 Drives Spontaneous Firing of Insect Octopaminergic Neurosecretory Cells.

    Science.gov (United States)

    Lapied, Bruno; Defaix, Antoine; Stankiewicz, Maria; Moreau, Eléonore; Raymond, Valérie

    2017-01-01

    Identification of the different intracellular pathways that control phosphorylation/dephosphorylation process of ionic channels represents an exciting alternative approach for studying the ionic mechanisms underlying neuronal pacemaker activity. In the central nervous system of the cockroach Periplaneta americana, octopaminergic neurons, called dorsal unpaired median (DUM; DUM neurons), generate spontaneous repetitive action potentials. Short-term cultured adult DUM neurons isolated from the terminal abdominal ganglion (TAG) of the nerve cord were used to study the regulation of a tetrodotoxin-sensitive low-voltage-activated (LVA) channel permeable to sodium and calcium (Na/Ca), under whole cell voltage- and current-clamp conditions. A bell-shaped curve illustrating the regulation of the amplitude of the maintained current vs. [ATP]i was observed. This suggested the existence of phosphorylation mechanisms. The protein kinase A (PKA) inhibitor, H89 and elevating [cyclic adenosine 3', 5' monophosphate, cAMP]i, increased and decreased the current amplitude, respectively. This indicated a regulation of the current via a cAMP/PKA cascade. Furthermore, intracellular application of PP2B inhibitors, cyclosporine A, FK506 and PP1/2A inhibitor, okadaic acid decreased the current amplitude. From these results and because octopamine (OA) regulates DUM neuron electrical activity via an elevation of [cAMP]i, we wanted to know if, like in vertebrate dopaminergic neurons, OA receptor (OAR) stimulation could indirectly affect the current via PKA-mediated phosphorylation of Dopamine- and cAMP-regulated Phosphoprotein-32 (DARPP-32) known to inhibit PP1/2A. Experiments were performed using intracellular application of phospho-DARPP-32 and non-phospho-DARPP-32. Phospho-DARPP-32 strongly reduced the current amplitude whereas non-phospho-DARPP-32 did not affect the current. All together, these results confirm that DARPP-32-mediated inhibition of PP1/2A regulates the maintained sodium/calcium

  1. Silicate fertilizer and irrigation depth in corn production

    Directory of Open Access Journals (Sweden)

    Edvaldo Eloy Dantas Júnior

    2013-08-01

    Full Text Available Calcium-magnesium silicates improve the soil physicochemical properties and provide benefits to plant nutrition, since they are sources of silica, calcium and magnesium. The objective of this study was to evaluate the grain yield of irrigated corn fertilized with calcium-magnesium silicate. The experiment was carried out in a greenhouse in Campina Grande - PB, Brazil, using plastic pots containing 80 kg of soil. The treatments consisted of the combination of four irrigation depths, related to water replacement of 50, 75, 100 and 125% of the crop evapotranspiration, with fertilizer levels of 0, 82, 164 and 246 g of calcium-magnesium silicate, with three replications. The experimental design was in randomized blocks, with the irrigation depths distributed in bands while the silicon levels constituted the subplots. Corn yield was influenced by calcium-magnesium silicate and by irrigation depth, obtaining the greatest grain yield with the dose of 164 g pot-1 irrigated at the highest water level. The water-use efficiency of in corn production tended to decrease when the irrigation depth was increased. The best water-use efficiency was observed when the irrigation level was between 87 and 174 mm, and the dose of silicate was 164 g pot-1.

  2. Interpretation of relevance of sodium-calcium exchange in action potential of diabetic rat heart by mathematical model.

    Science.gov (United States)

    Yaras, Nazmi; Turan, Belma

    2005-01-01

    Sarcolemmal Na+-Ca2+ exchange plays a central role in ion transport of the myocardium and the current carried with it contributes to the late phase of the action potential (AP) besides the contribution of outward K+-currents. In this study, the mathematical model for AP of the diabetic rat ventricular myocytes [34] was modified and used for the diabetic rat papillary muscle. We used our experimentally measured values of two K+-currents; transient outward current, Ito and steady-state outward current, Iss, as well as L-type Ca2+-current, I(CaL), then compared with the simulated values. We have demonstrated that the prolongation in the AP of the papillary muscle of the diabetic rats are not due to the alteration of I(CaL) but mainly due to the inhibition of the K+-currents and also the Na+-Ca2+ exchanger current, I(Na-Ca). In combination with our experimental data on sodium-selenite-treated diabetic rats, our simulation results provide new information concerning plausible ionic mechanisms, and second a possible positive effect of selenium treatment on the altered I(Na-Ca) for the observed changes in the AP duration of streptozotocin-induced diabetic rat heart.

  3. 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.

  4. The influence of calcium magnesium, and sodium on the spectrographic analysis of natural waters; Estudio de la influencia del calcio, magnesio y sodio en un metodo de analisis espectrografico de aguas naturales

    Energy Technology Data Exchange (ETDEWEB)

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

    1969-07-01

    The influences of 1000 {mu}g/ml of calcium and sodium and 300 {mu}g/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.

  5. Intercomparison 9711. pH, conductivity, alkalinity, nitrate + nitrite, chloride, sulfate, calcium, magnesium, sodium, potassium, total aluminium, reactive and non-labile aluminium, dissolved organic carbon, and chemical oxygen demand (ICP Waters report)

    OpenAIRE

    Hovind, H.

    1997-01-01

    47 laboratories in 22 countries participated in intercomparison 9711. One sample set for the determination of major ions, organic matter and aluminium fractions, were used. Based on the general target accuracy of + 20%, 78% of the results were acceptable. More than 80% of the result pairs were acceptable for chloride, sulfate, calcium, mangnesium, sodium, dissolved organic carbon and chemical oxygen demand. For pH only 43% of the result pairs were acceptable in relation to the extended target...

  6. Deep formation waters of Western Europe, Russia and North America characterised by sodium, calcium, magnesium and chloride concentrations

    Science.gov (United States)

    Bozau, Elke; Hemme, Christina; Sattler, Carl-Diedrich; van Berk, Wolfgang

    2015-04-01

    Deep formation water can be classified according to depth, temperature, and salinity (e.g., Graf et al. 1966, Kharaka & Hanor 2007). Most of the deep formation waters contain dissolved solids in excess of sea water. The hydrogeochemical development of formation water has been discussed for a long time. It is widely accepted that deep aquifers are influenced by the meteoric cycle and geochemical processes within the crust (e.g., Hebig et al. 2012). Similar hydrogeochemical signatures are found in deep formation waters of all continents and can be explained by general geochemical processes within the deep reservoirs (e.g., Land 1995). Therefore, data of deep formation waters from Western Europe, Russia, and North America are collected and classified by the major water components. The data are used to identify important hydrogeochemical processes (e.g., halite dissolution and albitisation) leading to different compositions of formation water. Two significant water types are identified: Na-Cl water and Na-Ca-Cl water. Based on the collected hydrogeochemical data, development trends are stated for the formation waters, and albitisation is favoured as the main process for calcium enrichment. Furthermore, differences of formation water according to stratigraphical units are shown for deep reservoirs of the North German Basin and the North Sea. References: Graf, D.L., 1982. Chemical osmosis, reverse chemical osmosis, and the origin of subsurface brines. Geochimica Cosmochimica Acta 46, 1431-1448. Hebig, K.H., Ito, N., Scheytt, T., Marui, A., 2012. Review: Deep groundwater research with focus on Germany. Hydrogeology Journal 20, 227-243. Kharaka, Y.K., Hanor, J.S., 2007. Deep fluids in continents: I. Sedimentary Basins. Treatise on Geochemistry 5, 1-48. Land, L.S., 1995. The role of saline formation water in the crustal cycling. Aquatic Geochemistry 1, 137-145. Acknowledgements: The presented data are results of the collaborative research program "gebo" (Geothermal energy

  7. Synthesis of magnesium silicate from wheat husk ash: Effects of parameters on structural and surface properties

    OpenAIRE

    Pinar Terzioglu; Sevil Yucel

    2012-01-01

    In the present study, magnesium silicate was produced by using wheat husk ash. Wheat husk was burned at 600 °C to obtain an amorphous ash structure, and the ash was processed with sodium hydroxide solution with heat to extract silica. Sodium silicate solution and magnesium salts were used to synthesize magnesium silicate. The present study investigates effects of the feeding rate on magnesium silicate production (0.6 mL/min, 35 mL/min, 70 mL/min), the type of magnesium salt (MgSO4 • 7H2O or M...

  8. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  9. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  10. Comparison of silicon nanoparticles and silicate treatments in fenugreek.

    Science.gov (United States)

    Nazaralian, Sanam; Majd, Ahmad; Irian, Saeed; Najafi, Farzaneh; Ghahremaninejad, Farrokh; Landberg, Tommy; Greger, Maria

    2017-06-01

    Silicon (Si) fertilization improves crop cultivation and is commonly added in the form of soluble silicates. However, most natural plant-available Si originates from plant formed amorphous SiO2 particles, phytoliths, similar to SiO2-nanoparticles (SiNP). In this work we, therefore, compared the effect by sodium silicate and that of SiNP on Si accumulation, activity of antioxidative stress enzymes catalase, peroxidase, superoxide dismutase, lignification of xylem cell walls and activity of phenylalanine ammonia-lyase (PAL) as well as expression of genes for the putative silicon transporter (PST), defensive (Tfgd 1) and phosphoenolpyruvate carboxykinase (PEPCK) and protein in fenugreek (Trigonella foenum-graecum L.) grown in hydroponics. The results showed that Si was taken up from both silicate and SiNP treatments and increasing sodium silicate addition increased the translocation of Si to the shoot, while this was not shown with increasing SiNP addition. The silicon transporter PST was upregulated at a greater level when sodium silicate was added compared with SiNP addition. There were no differences in effects between sodium silicate and SiNP treatments on the other parameters measured. Both treatments increased the uptake and accumulation of Si, xylem cell wall lignification, cell wall thickness, PAL activity and protein concentration in seedlings, while there was no effect on antioxidative enzyme activity. Tfgd 1 expression was strongly downregulated in leaves at Si addition. The similarity in effects by silicate and SiNP would be due to that SiNP releases silicate, which may be taken up, shown by a decrease in SiNP particle size with time in the medium. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Low-temperature fabrication of macroporous scaffolds through foaming and hydration of tricalcium silicate paste and their bioactivity

    NARCIS (Netherlands)

    Huan, Z.; Chang, J.; Zhou, J.

    2009-01-01

    A low-temperature fabrication method for highly porous bioactive scaffolds was developed. The two-step method involved the foaming of tricalcium silicate cement paste and hydration to form calcium silicate hydrate and calcium hydroxide. Scaffolds with a combination of interconnected macro- and

  12. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Giudice

    2007-01-01

    Full Text Available The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses were previously characterized. Experimental panels were tested in a limiting oxygen chamber and in a two-foot tunnel. Results displayed a high fire-retardant efficiency using some soluble silicates.

  13. The Effect of a Novel Highly Selective Inhibitor of the Sodium/Calcium Exchanger (NCX) on Cardiac Arrhythmias in In Vitro and In Vivo Experiments.

    Science.gov (United States)

    Kohajda, Zsófia; Farkas-Morvay, Nikolett; Jost, Norbert; Nagy, Norbert; Geramipour, Amir; Horváth, András; Varga, Richárd S; Hornyik, Tibor; Corici, Claudia; Acsai, Károly; Horváth, Balázs; Prorok, János; Ördög, Balázs; Déri, Szilvia; Tóth, Dániel; Levijoki, Jouko; Pollesello, Piero; Koskelainen, Tuula; Otsomaa, Leena; Tóth, András; Baczkó, István; Leprán, István; Nánási, Péter P; Papp, Julius Gy; Varró, András; Virág, László

    2016-01-01

    In this study the effects of a new, highly selective sodium-calcium exchanger (NCX) inhibitor, ORM-10962 were investigated on cardiac NCX current, Ca2+ transients, cell shortening and in experimental arrhythmias. The level of selectivity of the novel inhibitor on several major transmembrane ion currents (L-type Ca2+ current, major repolarizing K+ currents, late Na+ current, Na+/K+ pump current) was also determined. Ion currents in single dog ventricular cells (cardiac myocytes; CM), and action potentials in dog cardiac multicellular preparations were recorded utilizing the whole-cell patch clamp and standard microelectrode techniques, respectively. Ca2+ transients and cell shortening were measured in fluorescent dye loaded isolated dog myocytes. Antiarrhythmic effects of ORM-10962 were studied in anesthetized ouabain (10 μg/kg/min i.v.) pretreated guinea pigs and in ischemia-reperfusion models (I/R) of anesthetized coronary artery occluded rats and Langendorff perfused guinea pigs hearts. ORM-10962 significantly reduced the inward/outward NCX currents with estimated EC50 values of 55/67 nM, respectively. The compound, even at a high concentration of 1 μM, did not modify significantly the magnitude of ICaL in CMs, neither had any apparent influence on the inward rectifier, transient outward, the rapid and slow components of the delayed rectifier potassium currents, the late and peak sodium and Na+/K+ pump currents. NCX inhibition exerted moderate positive inotropic effect under normal condition, negative inotropy when reverse, and further positive inotropic effect when forward mode was facilitated. In dog Purkinje fibres 1 μM ORM-10962 decreased the amplitude of digoxin induced delayed afterdepolarizations (DADs). Pre-treatment with 0.3 mg/kg ORM-10962 (i.v.) 10 min before starting ouabain infusion significantly delayed the development and recurrence of ventricular extrasystoles (by about 50%) or ventricular tachycardia (by about 30%) in anesthetized guinea pigs

  14. Suprimento do silicato de cálcio e a eficiência nutricional de variedades de cafeeiro Effect of calcium silicate suplly and the nutritional efficiency of coffee cultivars

    Directory of Open Access Journals (Sweden)

    Adélia Aziz Alexandre Pozza

    2009-12-01

    Full Text Available Embora não seja considerado nutriente essencial às plantas, o Si é classificado como elemento benéfico ou útil, mas pode alterar a dinâmica nutricional das plantas. Objetivando comparar a eficiência nutricional de variedades de cafeeiro (Catuaí, Mundo Novo e Icatu em resposta à adubação silicatada, realizou-se um experimento em blocos casualizados, com as três variedades de mudas em tubetes combinadas com seis doses de CaSiO3 (T0 = 0, T1 = 0,063, T2 = 0,125, T3 = 0,25, T4 = 0,5 e T5 = 1,0 g dm-3 de substrato. A variedade Icatu teve a maior eficiência de absorção (EA de Cu, Zn, Fe e Si, maior eficiência de uso (EU de N, K, Ca, B e Mn, não diferindo da Mundo Novo com relação aos nutrientes N, Ca e Mn, e maior eficiência de translocação (ET de N, S, Zn e de Fe. A Catuaí teve maior EA de P, K, B e Mn, não diferindo da Mundo Novo com relação aos nutrientes P, K e Mn, maior EU para Mg, S, Cu, Zn, Fe e Si, provavelmente devido à melhor ET desses nutrientes, exceto para Fe e Si. A Mundo Novo foi mais eficiente na absorção de N, K, Ca, Mg, Mn e Si, teve maior EU de P e Mn e maior ET de K, Ca, B, Mn e Si.Silicon is classified as a beneficial nutrient and can improve the nutritional dynamics of plants, although it is not considered an essential nutrient for plants. In an experiment in a randomized block design, three coffee cultivars (Catuaí, Mundo Novo and Icatu were planted in plastic tubes, combined with six doses of calcium silicate (T0=0, T1=0.063, T2=0.125, T3=0.25, T4=0.5 and T5=1.0 g dm-3 substrate, to compare the nutritional efficiency of the cultivars in response to silicon fertilization. Cultivar Icatu showed the higher uptake efficiency (UE of Cu, Zn, Fe, and Si, and efficiency of use (EU of N, K, Ca, B, and Mn, but the later did not differ from Mundo Novo cultivar (N, Ca, and Mn. The efficiency of translocation (ET was higher for N, S, Zn, and Fe. For Catuaí the uptake efficiency of P, K, B, and Mn was higher

  15. Evaluation of status of calcium, magnesium, potassium, and sodium levels in biological samples in children of different age groups with normal vision and night blindness.

    Science.gov (United States)

    Afridi, Hassan Imran; Kazi, Tasneem Gul; Kazi, Naveed; Kandhro, Ghulam Abbas; Baig, Jameel Ahmed; Shah, Abdul Qadir; Khan, Sumaira; Kolachi, Nida Fatima; Wadhwa, Sham Kumar; Shah, Faheem

    2011-01-01

    The most common cause of blindness in developing countries is vitamin A deficiency. The World Health Organization (WHO) estimates 13.8 million children have some degree of visual loss related to vitamin A deficiency. The causes of night blindness in children are multifactorial and particular consideration has been given to childhood nutritional deficiency, which is the most common problem found in underdeveloped countries. Such deficiency can result in physiological and pathological processes that in turn influence biological sample composition. Vitamin and mineral deficiency prevents more than two billion people from achieving their full intellectual and physical potential. This study was designed to compare the levels of magnesium (Mg), calcium (Ca), potassium (K), and sodium (Na) in scalp hair, serum, blood, and urine of night blindness children in two age groups, (1-5) and (6-10) years, of both genders comparing them to sex- and age-matched controls. A microwave assisted wet acid digestion procedure was developed as a sample pretreatment for the determination of Mg, Ca, K, and Na in biological samples of children with night blindness. The proposed method was validated by using conventional wet digestion and certified reference samples of hair, serum, blood, and urine. The digests of all biological samples were analysed for Mg, Ca, K, and Na by flame atomic absorption spectrometry (FAAS) using an air/acetylene flame. The results indicated significantly lower levels of Mg, Ca, and K in the biological samples (blood, serum, and scalp hair) of male and female children with night blindness and higher values of Na compared with control subjects of both genders. These data present guidance to clinicians and other professionals investigating deficiency of essential mineral elements in biological samples (scalp hair, serum, and blood) of children with night blindness.

  16. Non-free ionic transport of sodium, magnesium, and calcium in streams of two adjacent headwater catchments with different vegetation types in Japan

    Science.gov (United States)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2017-01-01

    Sodium (Na), magnesium (Mg), calcium (Ca) are usually believed to occur mostly as free ions in the fresh water and consequently little is known about their chemical species. To understand the importance of non-free ionic fractions (NIF) of major metals in freshwater streams, Na, Mg, Ca, silicon (Si), and fulvic acid-like materials (FAM) were measured in streams of mountainous adjacent headwater catchments dominated by different vegetation types (planted evergreen coniferous forest and natural deciduous broadleaf forest). During both no rainfall periods and rainstorms, the proportion of NIF relative to total elements was lower in the coniferous catchment than in the deciduous catchment, although it sometimes accounted for half or more of the total concentrations of Na, Mg, and Ca in both catchments. The solubility of metal compounds was higher than the measured maximum concentrations of Na+, Mg2+, and Ca2+ to the extent that inorganic bonding was hardly possible. During no rainfall periods when FAM was slightly produced into the streams, the fluxes of NIF and Si were highly correlated (r > 0.92, p NIF correlated weakly with that of Si but did not correlate with that of FAM in both catchments. In contrast, during a heavy rainstorm, the flux of NIF correlated strongly (r ⩾ 0.83, p NIF originated in the quick-flow component (i.e., surface or near-surface water) in stream water (ΔNIF) correlated strongly (r ⩾ 0.81, p < 0.0001, n = 22) with that of FAM. These findings imply that heavy rainstorms may enhance the bonding of the major metals with humic substances mainly in the deciduous catchment; and also exhibit that, in the headwater catchments, both water flow pathways resulted from the different vegetation types play a very important role to promote the bonding of major metals with humic substances in stream water.

  17. Suitability assessment of grey water quality treated with an upflow-downflow siliceous sand/marble waste filtration system for agricultural and industrial purposes.

    Science.gov (United States)

    Chaabane, Safa; Riahi, Khalifa; Hamrouni, Hédi; Thayer, Béchir Ben

    2017-04-01

    The present study examines the suitability assessment of an upflow-downflow siliceous sand/marble waste filtration system for treatment and reuse of grey water collected from bathrooms of the student residential complex at the Higher Institute of Engineering Medjez El Bab (Tunisia). Once the optimization of grey water pre-treatment system has been determined, the filtration system was operated at different hydraulic loading rate and media filter proportions in order to assess the suitability of treated grey water for irrigational purpose according to salinity hazard, sodium hazard, magnesium hazard, permeability index, water infiltration rate, and widely used graphical methods. Suitability of the treated grey water for industrial purpose was evaluated in terms of foaming, corrosion, and scaling. Under optimal operational conditions, results reveals that treated grey water samples with an upflow-downflow siliceous sand/marble waste filtration system may be considered as a good and an excellent water quality suitable for irrigation purpose. However, treated grey water was found not appropriate for industrial purpose due to high concentrations of calcium and sodium that can generate foaming and scaling harm to boilers. These results suggest that treated grey water with an upflow-downflow siliceous sand/marble waste filtration system would support production when used as irrigation water.

  18. Effects of silicate application on soil fertility and wheat yield

    Directory of Open Access Journals (Sweden)

    Marcos Vinícius Mansano Sarto

    2015-12-01

    Full Text Available An improvement in soil chemical properties and crop development with silicate application has been confirmed in several plant species. The effects of silicate application on soil chemical properties and wheat growth were investigated in the present study. The experiment was carried out in 8-L plastic pots in a greenhouse. Treatments were arranged in a randomized block design in a 3 × 5 factorial: three soils [Rhodic Acrudox (Ox1, Rhodic Hapludox (Ox2 and Arenic Hapludult (Ult] and five silicate rates (0, 1, 2, 4 and 6 Mg ha–1 of calcium/magnesium silicate, with four replications. The plant length, number of spikes per pot, shoot dry matter and grain yield, were measured after 115 days of wheat (Triticum aestivum L. growth. Changes in the soil chemical properties (pH, H+ + Al3+, Al3+, P, K, Ca, Mg, Si, Cu, Zn, Fe and Mn were analyzed after wheat harvest. Application of calcium/magnesium silicate reduces the potential acidity (H+ + Al3+ and Al3+ phytotoxic; and increases the soil pH, available Ca, Mg and Si, cation exchange capacity (CEC and soil base saturation. Silicate application did not affect the available P, exchangeable K and availability of micronutrients (Cu, Zn, Fe and Mn in the three soils. The application of calcium/magnesium silicate in an acid clayey Rhodic Hapludox improves the development and yield of wheat; however, the silicate application in soil with pH higher to 5.3 and high Si availability does not affect the agronomic characteristics and grain yield of wheat. 

  19. Polymer-Layer Silicate Nanocomposites

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela

    Nowadays, some of the material challenges arise from a performance point of view as well as from recycling and biodegradability. Concerning these aspects, the development of polymer layered silicate nanocomposites can provide possible solutions. This study investigates how to obtain polymer layered...... silicate nanocomposites and their structure-properties relationship. In the first part of the thesis, thermoplastic layered silicates were obtained by extrusion. Different modification methods were tested to observe the intercalation treatment effect on the silicate-modifier interactions. The silicate...

  20. The utilization of waste by-products for removing silicate from mineral processing wastewater via chemical precipitation.

    Science.gov (United States)

    Kang, Jianhua; Sun, Wei; Hu, Yuehua; Gao, Zhiyong; Liu, Runqing; Zhang, Qingpeng; Liu, Hang; Meng, Xiangsong

    2017-11-15

    This study investigates an environmentally friendly technology that utilizes waste by-products (waste acid and waste alkali liquids) to treat mineral processing wastewater. Chemical precipitation is used to remove silicate from scheelite (CaWO4) cleaning flotation wastewater and the waste by-products are used as a substitute for calcium chloride (CaCl2). A series of laboratory experiments is conducted to explain the removal of silicate and the characterization and formation mechanism of calcium silicate. The results show that silicate removal reaches 90% when the Ca:Si molar ratio exceeds 1.0. The X-ray diffraction (XRD) results confirm the characterization and formation of calcium silicate. The pH is the key factor for silicate removal, and the formation of polysilicic acid with a reduction of pH can effectively improve the silicate removal and reduce the usage of calcium. The economic analysis shows that the treatment costs with waste acid (0.63 $/m(3)) and waste alkali (1.54 $/m(3)) are lower than that of calcium chloride (2.38 $/m(3)). The efficient removal of silicate is confirmed by industrial testing at a plant. The results show that silicate removal reaches 85% in the recycled water from tailings dam. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The effectiveness of various chelates used alone or in combination with sodium hypochlorite in the removal of calcium hydroxide from root canals

    Directory of Open Access Journals (Sweden)

    Emel Uzunoglu

    2015-01-01

    Full Text Available Aim: To evaluate the effectiveness of various chelates used alone or in combination with sodium hypochlorite (NaOCl in the removal of calcium hydroxide (Ca(OH2 from root canals. Materials and Methods: The root canals of 72 mandibular incisors were prepared up to the ProTaper F2 file. Among these, six randomly selected teeth were used as negative and positive controls, while the root canals of the remaining 66 were filled with Ca(OH2 paste for 1 week. Then, the experimental group specimens were divided into six groups (n = 11. The access cavities were reopened and the Ca(OH2 paste in each group was removed using the following solutions: 2.5 mL ethylenediaminetetraacetic acid (EDTA; Group 1, 2.5 mL peracetic acid (PAA; Group 2, 2.5 mL QMix (Group 3, 2.5 mL NaOCl/2.5 mL EDTA (Group 4, 2.5 mL NaOCl/2.5 mL PAA (Group 5, and 2.5 mL NaOCl/2.5 mL QMix (Group 6. Digital photographs of longitudinally split specimens were imported into image analyzer software, and the amount of residual Ca (OH 2 was recorded as a percentage of the overall canal surface area. The results were analyzed using Kruskal–Wallis and Conover–Dunn tests. Results: The canal walls in the positive control group were completely covered with Ca(OH 2 compared with those in the negative control group. The lowest Ca(OH2 removal efficiency was observed for Group 4 (P < 0.001, while Group 6 showed favorable results (P < 0.05. Conclusions: QMix combined with NaOCl can remove Ca(OH2 from root canals as effectively as 17% EDTA and 1% PAA. The type and sequence of irrigants are more important than the total irrigant volume for effective Ca(OH 2 removal.

  2. 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)

  3. Intercomparison 9610, pH, conductivity, alkalinity, nitrate + nitrite, chloride, sulfate, calcium, magnesium, sodium, potassium, total aluminium, reactive and non-labile aluminium, dissolved organic carbon, and chemical oxygen demand (ICP Waters report)

    OpenAIRE

    Hovind, H.

    1996-01-01

    36 laboratories in 21 countries participated in intercomparison 9610. Two sample sets, one for the major ions and one for organic matter and aluminium fractions, were used. Based on the general target accuracy of + 20%, 70% of the results were acceptable. More than 80% of the result pairs were acceptable for conductivity, nitrate+nitrite, calcium, sodium and dissolved organic carbon. For pH only 55% of the result pairs were acceptable in relation to the extended target accuracy of + 0.2 units...

  4. Silicate Urolithiasis during Long-Term Treatment with Zonisamide

    Directory of Open Access Journals (Sweden)

    Satoru Taguchi

    2013-01-01

    Full Text Available Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.

  5. FFTF horizontal sodium storage tank preliminary thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J.J.

    1995-02-21

    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 drain tanks will be cylindrical vertical tanks having a diameter of 28 feet, height of 22 feet and fabricated from carbon steel. The vertical tanks were the subject of a previous report and are not the subject of this report. The fourth tank is a horizontal cylindrical tank 18 feet in diameter, having an overall length of 31 feet and fabricated from carbon steel. The purpose of this work is to document the thermal analyses that were performed to ensure that the FFTF horizontal 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 drain tank is the type of insulation. The baseline case assumed four inches of calcium silicate insulation. An alternate case assumed refractory fiber (Cerablanket) insulation also with a thickness of four inches. Both cases assumed a total electrical trace heat load of 60 kW, evenly distributed on the tank heads and on the tank side wall (cylinder).

  6. FFTF vertical sodium storage tank preliminary thermal analysis

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J.J.

    1995-02-21

    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.

  7. Study of thermal effects of silicate-containing hydroxyapatites

    Science.gov (United States)

    Golovanova, O. A.; Zaits, A. V.; Berdinskaya, N. V.; Mylnikova, T. S.

    2016-02-01

    The possibility of modifications of hydroxyapatite silicate ions, from the extracellular fluid prototype solution under near-physiological conditions has been studied. Formation of silicon-structured hydroxyapatite with different extent of substitution of phosphate groups in the silicate group has been established through chemical and X-ray diffraction analyses, FTIR spectroscopy and optical microscopy. The results obtained are in agreement and suggest the possibility of substitution of phosphate groups for silicate groups in the hydroxyapatite structure when introducing different sources of silica, tetraethoxysilane and sodium silicate, in the reaction mixture. Growth in the amount of silicon in Si-HA results in the increase in the thermal stability of the samples. The greatest mass loss occurs at temperatures in the range of 25-400 0C that is caused by the removal of the crystallization and adsorption water and volatile impurities. It is shown that the modified apatites are of imperfect structure and crystallize in a nanocrystalline state.

  8. Effect of calcium and magnesium silicate on the growth of the castor oil plant subjected to salinity levels Efeito de silicato de cálcio e magnésio sobre o crescimento de plantas de mamoneira submetidas a níveis de salinidade

    Directory of Open Access Journals (Sweden)

    José Félix Brito Neto

    2012-12-01

    Full Text Available Salt stress decreases the osmotic potential of soil solution causing water stress, causing toxic effects in the plants resulting in injuries on the metabolism and nutritional disorders, thus compromising the plant growth, resulting in lower production. The calcium silicate and magnesium can perform the same function as limestone, besides providing silicon to plants, may also contribute to the resistance of plants to salt stress. Thus, the objective of this study was to evaluate the effect of calcium and magnesium silicate on the growth of the castor oil plant BRS Energia cultivated under saline conditions. This study evaluated plant height, stem diameter, number of leaves, leaf area, dry weight of shoot and root, and soil chemical characteristics. There was no interaction between factors of salinity level and of silicate level regarding the evaluated variables. There was a direct relationship between salinity levels and plant growth in height and stem diameter. The K concentration in soil were affected by salinity levels. O estresse salino diminui o potencial osmótico da solução do solo causando estresse hídrico, provocando efeitos tóxicos nas plantas que resultam em injúrias no metabolismo e desordens nutricionais, comprometendo assim o crescimento das plantas, resultando em menor produção. O silicato de cálcio e magnésio pode desempenhar a mesma função do calcário, além de fornecer silício para as plantas, podendo ainda, contribuir para a resistência de plantas ao estresse salino. Nesse sentido, objetivou-se com esse trabalho avaliar o efeito do silicato de cálcio e magnésio no crescimento da mamoneira BRS Energia cultivada sob condições salinas. Avaliou-se a altura da planta, diâmetro do caule, número de folhas, área foliar, massa seca da parte aérea e da raiz e as características químicas do solo. Não houve interação entre os fatores níveis de salinidade e silicato sobre as variáveis analisadas. Houve rela

  9. Artrodese na coluna cervical utilizando SICAP como substituto de enxerto ósseo Artrodesis en la columna cervical utilizando SICAP como sustituto de injerto óseo Cervical spine fusion utilizing silicated calcium phosphate bone graft substitute (SICAP

    Directory of Open Access Journals (Sweden)

    Juliano Fratezi

    2011-01-01

    Tech EE.UU, Reino Unido es un injerto óseo compuesto de calcio-fosfato con una sustitución de silicato en la estructura química, con una estructura tridimensional que parece hueso natural. MÉTODOS: 19 pacientes fueron sometidos a fusión ósea cervical y analizados retrospectivamente. La evaluación radiográfica y la evaluación clínica fueron realizadas utilizandose el cuestionario Neck Disability Index y la escala análoga del dolor (VAS pre y postoperación. RESULTADOS: El período promedio de seguimiento postoperatorio fue de 14 meses ± 5 meses (7-30 meses. Once pacientes fueron sometidos a fusión vía anterior; 5 pacientes vía posterior y 3 pacientes vía anterior y posterior. La revisión radiográfica mostró 19/19 (100% de fusión ósea, ningún caso presentó subsidencia, rotura o soltura de material de implante o movimiento en los niveles fusionados. Ningún ejemplo de osificación heterotópica o de crecimiento óseo intracanal fue observado. Clínicamente, el promedio de las puntuaciones del Neck Disability disminuyeron 13,3 puntos (promedio preop. de 34,5, postop. de 21,2, mejora de 39%, el promedio de VAS para dolor cervical disminuyó 2 puntos (2,7 preop. para 0,7 postop.; mejora de 74,1%. No fueron observadas complicaciones como infección, osteólisis o edema excesivo de las partes blandas. CONCLUSIÓN: Los resultados preliminares obtenidos en esta serie feuron estimulantes con el uso de SICaP como injerto óseo, con sólida fusión ósea obtenida en todos los casos y sin formación de osificación heterotópica o crecimiento de hueso intracanal. SIcaP demuestra ser un sustituto confiable para el injerto óseo autólogo en la columna cervical.OBJECTIVE: Bone graft substitutes have been developed to obviate the need for autograft from the iliac crest and its resultant complications. SiCaP (Actifuse, ApaTech US, UK is a calcium phosphate bone graft substitute with selective controlled silicate substitution in a patented 3-dimensional structure

  10. The effect of a high-protein, high-sodium diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use

    DEFF Research Database (Denmark)

    Harrington, M.; Bennett, T.; Jakobsen, Jette

    2004-01-01

    randomly assigned to a diet high in protein ( 90 g/day) and sodium (180 mmol/day) ( calciuric diet) or a diet moderate in protein ( 70 g/day) and low in sodium ( 65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P......The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women ( aged 49 - 60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n = 8 HRT users (+HRT) and n = 10 nonusers (-HRT)) were...

  11. THE ALUMINA-SILICATES IN STABILIZATION PROCESSES IN FLUIDIZED-BED ASH

    Directory of Open Access Journals (Sweden)

    IVANA PERNA

    2011-03-01

    Full Text Available Presented study of coal fluidized-bed ash solidification was accompanied with specific studies of alumino-silicates residues in ashes. The specific technology of fluid coal burning and its relatively low temperature combustion combines coal burning and decomposition of calcium carbonate added to the fluid layer in the main endeavor to capture all sulfur oxides. The burning temperature seems be decisive to the behavior of clayed residues and calcium carbonate decomposition in connection for the future solidification of fluidized bed ash. The calcareous substances in combination with alumino-silicate residues form solid bodies where silicates play decisive role of long-term stability and insolubility of obtained solids. The position of aluminum ions in clayed residues of burned coal were studied by MAS-NMR with attention on aluminum ion coordination to oxygen and formation of roentgen amorphous phase of poly-condensed calcium alumina-silicate.

  12. Method of chemical analysis of silicate rocks (1962); Methode d'analyse chimique des roches silicatees (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Pouget, R. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1962-07-01

    A rapid method of analysis for the physical and chemical determination of the major constituents of silicate rocks is described. Water losses at 100 deg. C and losses of volatile elements at 1000 deg. C are estimated after staying in oven for these temperatures, or by mean of a thermo-balance. The determination of silica is made by a double insolubilization with hydrochloric acid on attack solution with sodium carbonate; total iron and aluminium, both with calcium and magnesium, after ammoniacal precipitation of Fe and Al, are determined on the filtration product of silica by titrimetry-photometry of their complexes with EDTA. The alkalis Na and K by flame spectrophotometry, Mn by colorimetry of the permanganate, and Ti by mean of his complex with H{sub 2}O{sub 2}, are determined on fluosulfuric attack solution. Phosphorus is determined by his complex with 'molybdenum blue' on a fluoro-nitro-boric attack solution; iron is estimated by potentiometry, with the help of bichromate on hydrofluoric solution. (author) [French] Une methode d'analyse rapide est decrite pour la determination physico-chimique des constituants principaux des roches silicatees. Les pertes en eau a 100 deg. C et en matieres volatiles a 1000 deg. C sont evaluees apres passage au four a ces temperatures, ou a l'aide d'une thermobalance. La determination de la silice se fait par double insolubilisation a l'acide chlorhydrique, sur une attaque au carbonate de sodium; le fer total et l'aluminium ainsi que le calcium et le magnesium, apres precipitation a l'ammoniaque des deux premiers metaux, sont determines sur le filtrat de la silice par titrimetrie-photometrie de leurs complexes avec l'E.D.T.A. Les alcalins sodium et potassium par spectrophotometrie de flamme, le manganese par colorimetrie du permanganate, le titane a l'aide de son complexe avec l'eau oxygenee, sont determines sur une attaque fluosulfurique. Le phosphore est determine par son

  13. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette Rica; Krøyer, Hanne

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates...... is that the cement paste structure and porosity can be engineered by addition of selected layer silicates having specific particle shapes and surface properties (e.g., charge and specific surface area). This seems to be due to the growth of calcium-silicate hydrates (C-S-H) on the clay particle surfaces......, and the nano-structure of the C-S-H depends on type of layer silicate. The effect of layer silicate addition is most pronounced for palygorskite and smectite having the largest surface area and negative charges on the particle surfaces. The cement pastes containing palygorskite and bentonite have...

  14. Influence of portland cement replacement in high calcium fly ash geopolymer paste

    Directory of Open Access Journals (Sweden)

    Tanakorn Phoo-ngernkham

    2014-03-01

    Full Text Available This article presents the influence of ordinary Portland cement (OPC replacement in high calcium fly ash (FA geopolymer paste. FA was used to replace OPC at the rate of 5, 10 and 15% by mass of binder. Sodium silicate (Na2SiO3 and 10 molar sodium hydroxide (NaOH solutions were used as the alkaline solution in the reaction. The Na2SiO3/NaOH ratio of 2.0 and the liquid/binder (L/B ratio of 0.60 were used in all mixtures. The results of increase OPC replacement, the setting time and compressive strain capacity decreased while the compressive strength and modulus of elasticity increased. The compressive strength and modulus of elasticity at 28 days of geopolymer pastes with 15% OPC replacement were 36.7 MPa and 13,300 MPa, respectively.

  15. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  16. Thermochemistry of Silicates

    Science.gov (United States)

    Costa, Gustavo; Jacobson, Nathan

    2015-01-01

    The thermodynamic properties of vapor and condensed phases of silicates are crucial in many fields of science. These quantities address fundamental questions on the formation, stability, transformation, and physical properties of silicate minerals and silicate coating compositions. Here the thermodynamic activities of silica and other species in solid solution have been measured by the analysis of the corresponding high temperature vapors using Knudsen Effusion Mass Spectrometry (KEMS). In first set of experiments KEMS has been used to examine the volatility sequence of species (Fe, SiO, Mg, O2 and O) present in the vapor phase during heating of fosterite-rich olivine (Fo93Fa7) up to 2400 C and to measure the Fe, SiO and Mg activities in its solid solution. The data of fosterite-rich olivine are essential for thermochemical equilibrium models to predict the atmospheric and surface composition of hot, rocky exoplanets (Lava Planets). In the second set of experiments the measured thermodynamic activities of the silica in Y2O3-SiO2 and Yb2O3-SiO2 systems are used to assess their reactivity and degradation recession as environmental barrier coatings (EBCs) in combustion environments (e.g. non-moveable parts of gas turbine engine).

  17. Efeito do silicato de cálcio e da autoclavagem na supressividade e na conducividade de dois solos à Rhizoctonia solani Influence of calcium silicate and sterilization on the natural suppressiveness and on the conduciveness of two soils to Rhizoctonia solani

    Directory of Open Access Journals (Sweden)

    Fabrício de Ávila Rodrigues

    1999-08-01

    Full Text Available Objetivou-se verificar o efeito da aplicação de silicato de cálcio e da esterilização na supressividade natural de um Latossolo Vermelho-Escuro (LEa álico textura muito argilosa e na conducividade natural de uma Terra Roxa Estruturada eutrófica (TRe ao fungo Rhizoctonia solani, em condições de casa de vegetação. Utilizou-se o delineamento inteiramente casualizado em esquema fatorial 2 x 3 x 2. Os fatores foram: duas classes de solo (LEa e TRe - 0-20 cm; três tratamentos (esterilização ou não por autoclavagem, aplicação de silicato e testemunha e infestação ou não com R. solani, com três repetições e 16 plântulas de feijoeiro por parcela. A aplicação de silicato foi feita incorporando 0,63 g do produto em 1 kg de cada material de solo, seguido de incubação por 30 dias. Para promover a infestação artificial, foram colocados 800 mg de inóculo em 1 kg de cada material de solo. O silicato de cálcio aumentou os teores de Ca trocável e a soma de bases nos dois solos. Um decréscimo na saturação por Al de 70 para 19% e um aumento na saturação por bases de 9 para 21% alteraram significativamente a supressividade natural do LEa à R. solani. Com relação à TRe, a aplicação de silicato não teve nenhum efeito na sua conducividade, dado ao seu natural caráter eutrófico, o qual já é favorável ao desenvolvimento deste fungo. A esterilização não influiu no desenvolvimento de R. solani, o que sugere que os fatores abióticos foram os responsáveis pela supressividade ou conducividade desses solos.The effect of calcium silicate slag and soil sterilization on the natural suppressiveness of a Typic Acrustox (clay Dark Red Latosol -- LEa and the natural conduciveness of an Oxic Haplustoll (TRe to Rhizoctonia solani were studied under greenhouse conditions. The experimental design was a three-replicate completely randomized one, with 2 x 3 x 2 factorial combination of the following treatments: two soil kinds (LEa and

  18. Minerals and Sarcopenia; The Role of Calcium, Iron, Magnesium, Phosphorus, Potassium, Selenium, Sodium, and Zinc on Muscle Mass, Muscle Strength, and Physical Performance in Older Adults: A Systematic Review.

    Science.gov (United States)

    van Dronkelaar, Carliene; van Velzen, Aafke; Abdelrazek, Maya; van der Steen, Anouk; Weijs, Peter J M; Tieland, Michael

    2017-07-12

    Minerals may contribute to prevent and treat sarcopenia, the age-related loss of muscle mass, muscle strength, and physical performance. So far, there is no comprehensive review on the impact of minerals on sarcopenia outcomes. The aim of this systematic review is to evaluate the role of calcium, iron, magnesium, phosphorus, potassium, selenium, sodium, and zinc on muscle mass, muscle strength, and physical performance in older adults. A systematic search was conducted between March 2016 and July 2016, in the PubMed database using predefined search terms. Articles on the role of dietary mineral intake or mineral serum concentrations on muscle mass, muscle strength, physical performance, and/or the prevalence of sarcopenia in healthy or frail older adults (average age ≥ 65 years) were selected. Only original research publications were included. The search and data extraction were conducted in duplicate by 2 independent researchers. The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement was followed in constructing this systematic review. The Effective Public Health Practice Project (EPHPP) Quality Assessment Tool for Quantitative Studies was used to evaluate the quality of the selected articles. From the 3346 articles found, a total of 10 studies met the inclusion criteria. Observational studies showed that serum selenium (n = 1) and calcium intake (n = 1) were significantly associated with muscle mass, and magnesium (n = 1), selenium (n = 1), iron (n = 1), and zinc (n = 1) intake were significantly and positively associated with physical performance in older adults. Furthermore, magnesium (n = 2), selenium (n = 2), calcium (n = 2), and phosphorus (n = 1) intake were associated with the prevalence of sarcopenia. Magnesium supplementation improved physical performance based on one randomized controlled trial. No studies on the role of sodium or potassium on muscle mass, muscle strength, or physical performance were

  19. Simultaneous determination of free calcium, magnesium, sodium and potassium ion concentrations in simulated milk ultrafiltrate and reconstituted skim milk using the Donnan Membrane Technique

    NARCIS (Netherlands)

    Gao, R.; Temminghoff, E.J.M.; Leeuwen, van H.P.; Valenberg, van H.J.F.; Eisner, M.D.; Boekel, van M.A.J.S.

    2009-01-01

    This study focused on determination of free Ca2+, Mg2+, Na+ and K+ concentrations in a series of CaCl2 solutions, simulated milk ultrafiltrate and reconstituted skim milk using a recently developed Donnan Membrane Technique (DMT). A calcium ion selective electrode was used to compare the DMT

  20. Biological and therapeutic effects of ortho-silicic acid and some ortho-silicic acid-releasing compounds: New perspectives for therapy

    Directory of Open Access Journals (Sweden)

    Jurkić Lela Munjas

    2013-01-01

    Full Text Available Abstract Silicon (Si is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4, as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K, the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel, silica gel (amorphous silicon dioxide, and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4 in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources.

  1. 21 CFR 73.2125 - Potassium sodium copper chlorophyllin (chlorophyllin-copper complex).

    Science.gov (United States)

    2010-04-01

    ... pyrophosphate. Sorbitol. Magnesium phosphate, tribasic. Calcium carbonate. Calcium phosphate, dibasic. Sodium N... specifications to the requirements of § 73.1125(a)(1) and (b). (b) Uses and restrictions. Potassium sodium copper...

  2. 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....

  3. Durability Study on High Calcium Fly Ash Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Ganesan Lavanya

    2015-01-01

    Full Text Available This study presents an investigation into the durability of geopolymer concrete prepared using high calcium fly ash along with alkaline activators when exposed to 2% solution of sulfuric acid and 5% magnesium sulphate for up to 45 days. The durability was also assessed by measuring water absorption and sorptivity. Ordinary Portland cement concrete was also prepared as control concrete. The grades chosen for the investigation were M20, M40, and M60. The alkaline solution used for present study is the combination of sodium silicate and sodium hydroxide solution with the ratio of 2.50. The molarity of sodium hydroxide was fixed as 12. The test specimens were 150×150×150 mm cubes, 100×200 mm cylinders, and 100×50 mm discs cured at ambient temperature. Surface deterioration, density, and strength over a period of 14, 28, and 45 days were observed. The results of geopolymer and ordinary Portland cement concrete were compared and discussed. After 45 days of exposure to the magnesium sulfate solution, the reduction in strength was up to 12% for geopolymer concrete and up to 25% for ordinary Portland cement concrete. After the same period of exposure to the sulphuric acid solution, the compressive strength decrease was up to 20% for geopolymer concrete and up to 28% for ordinary Portland cement concrete.

  4. Carbonate-silicate ratio for soil correction and influence on nutrition, biomass production and quality of palisade grass

    Directory of Open Access Journals (Sweden)

    Renato Ferreira de Souza

    2011-10-01

    Full Text Available Silicates can be used as soil correctives, with the advantage of being a source of silicon, a beneficial element to the grasses. However, high concentrations of silicon in the plant would affect the digestibility of the forage. To evaluate the influence of the substitution of the calcium carbonate by calcium silicate on the nutrition, biomass production and the feed quality of the palisade grass [Urochloa brizantha (C. Hochstetter ex A. Rich. R. Webster], three greenhouse experiments were conducted in completely randomized designs with four replications. Experimental units (pots contained a clayey dystrophic Rhodic Haplustox, a sandy clay loam dystrophic Typic Haplustox and a sandy loam dystrophic Typic Haplustox. Each soil received substitution proportions (0, 25, 50, 75 and 100 % of the carbonate by calcium silicate. The increase in the proportion of calcium silicate elevated the concentrations and accumulations of Si, Ca, Mg, and B, reduced Zn and did not alter P in the shoot of plants. The effects of the treatments on the other nutrients were influenced by the soil type. Inclusion of calcium silicate also increased the relative nutritional value and the digestibility and ingestion of the forage, while the concentration and accumulation of crude protein and the neutral detergent and acid detergent fibers decreased. Biomass production and feed quality of the palisade grass were generally higher with the 50 % calcium silicate treatment.

  5. Comparing Salivary and Dental Plaque Content of Sodium, Calcium and Phosphate after Sucrose Ingestion between Salvadora persica Sticks and Tooth Brush Users

    OpenAIRE

    Wafaa Hussein Khalil; Mohammad Yousuf Mohammad Sukkar; Bakri Gobara Gismalla

    2017-01-01

    Dental caries is a biofilm-dependent oral disorder, resulting in its initiation and development from fermentable dietary carbohydrates as key environmental factors. Sucrose in particular, is considered as the most cariogenic of all carbohydrates; the biofilm forming in its presence is characterized by low concentrations of those critical ions involved in de- and re-mineralization of enamel and dentin, namely calcium, phosphates and fluoride content. Within this context, this present study aim...

  6. Influence of sodium, calcium, magnesium, and ammonium in the sorption of cadmium in a zeolite rock; Influencia del sodio, calcio, magnesio y amonio en la sorcion de cadmio en una roca zeolitica

    Energy Technology Data Exchange (ETDEWEB)

    Teutli S, E.A

    2007-07-01

    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)

  7. Calcium - urine

    Science.gov (United States)

    Urinary Ca+2; Kidney stones - calcium in urine; Renal calculi - calcium in your urine; Parathyroid - calcium in urine ... Urine calcium level can help your provider: Decide on the best treatment for the most common type of kidney ...

  8. Determination of reactivity rates of silicate particle-size fractions

    Directory of Open Access Journals (Sweden)

    Angélica Cristina Fernandes Deus

    2014-04-01

    Full Text Available The efficiency of sources used for soil acidity correction depends on reactivity rate (RR and neutralization power (NP, indicated by effective calcium carbonate (ECC. Few studies establish relative efficiency of reactivity (RER for silicate particle-size fractions, therefore, the RER applied for lime are used. This study aimed to evaluate the reactivity of silicate materials affected by particle size throughout incubation periods in comparison to lime, and to calculate the RER for silicate particle-size fractions. Six correction sources were evaluated: three slags from distinct origins, dolomitic and calcitic lime separated into four particle-size fractions (2, 0.84, 0.30 and <0.30-mm sieves, and wollastonite, as an additional treatment. The treatments were applied to three soils with different texture classes. The dose of neutralizing material (calcium and magnesium oxides was applied at equal quantities, and the only variation was the particle-size material. After a 90-day incubation period, the RER was calculated for each particle-size fraction, as well as the RR and ECC of each source. The neutralization of soil acidity of the same particle-size fraction for different sources showed distinct solubility and a distinct reaction between silicates and lime. The RER for slag were higher than the limits established by Brazilian legislation, indicating that the method used for limes should not be used for the slags studied here.

  9. The microstructure and surface morphology of radiopaque tricalcium silicate cement exposed to different curing conditions.

    Science.gov (United States)

    Formosa, L M; Mallia, B; Bull, T; Camilleri, J

    2012-05-01

    Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA). It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this research was to evaluate the microstructure and surface characteristics of radiopaque tricalcium silicate cement exposed to different curing conditions namely at 100% humidity or immersed in either water or a simulated body fluid at 37°C. The materials under study included tricalcium silicate and Portland cements with and without the addition of bismuth oxide radiopacifier. Material characterization was performed on hydrated cements using a combination of scanning electron microscopy (SEM) with X-ray energy dispersive (EDX) analyses and X-ray diffraction (XRD) analyses. Surface morphology was further investigated using optical profilometry. Testing was performed on cements cured at 100% humidity or immersed in either water or Hank's balanced salt solution (HBSS) for 1 and 28 days at 37°C. In addition leachate analysis was performed by X-ray fluorescence of the storage solution. The pH of the storage solution was assessed. All the cements produced calcium silicate hydrate and calcium hydroxide on hydration. Tricalcium silicate showed a higher reaction rate than Portland cement and addition of bismuth oxide seemed to also increase the rate of reaction with more calcium silicate hydrate and calcium hydroxide being produced as demonstrated by SEM and XRD analysis and also by surface deposits viewed by the optical profilometer. Cement immersion in HBSS resulted in the deposition of calcium phosphate during the early stages following immersion and extensive calcification after 28 days. The pH of all storage solutions was alkaline. The immersion in distilled water resulted in a higher pH of the solution than when the cements were immersed in HBSS. Leachate analysis demonstrated high calcium levels in all cements tested with higher levels in tricalcium silicate and

  10. Efeito da aplicação de silicato de cálcio no crescimento, no estado nutricional e na produção de matéria seca de mudas de maracujazeiro Effect of application of calcium silicate on growth, nutritional status and dry matter production of passion fruit seedlings

    Directory of Open Access Journals (Sweden)

    Renato de M. Prado

    2005-06-01

    Full Text Available Objetivou-se, com este trabalho, avaliar os efeitos da aplicação de um resíduo industrial (silicato de cálcio ao substrato de produção das mudas de maracujazeiro, como material corretivo, no desenvolvimento, na produção de matéria seca e no estado nutricional das plantas. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos e quatro repetições. As doses de silicato de cálcio foram aplicadas objetivando-se elevar a percentagem de saturação com bases 25, 50, 75 e 100%, correspondendo a 0,45; 0,90; 1,35 e 1,80 g por vaso, respectivamente, além da testemunha sem aplicação. A unidade experimental foi constituída por vasos com 2 dm³ de substrato de um Latossolo Vermelho distrófico. Após 80 dias da semeadura avaliaram-se: a altura, o número de folhas, o diâmetro do caule e a matéria seca da parte aérea e das raízes e, também, os teores de macro e micronutrientes. O resíduo de silicato de cálcio mostrou-se como corretivo de acidez do solo e como fonte de Ca, embora ineficiente fonte de Mg. O maior crescimento das mudas de maracujazeiro esteve associado à saturação por bases do solo de 58%, à concentração de Ca do solo de 19 mmol c dm-3 e teores de Ca na parte aérea de 12,0 g kg-1.This work was carried out with the objective of evaluating the effect of the addition of industrial residue (calcium silicate to the substrate in the production of the passion fruit seedlings, studying the benefits in the development, the production of dry matter and the nutritional state of the plants. The experimental design adapted was a randomized block with 5 treatments and 4 repetitions. The doses of calcium silicate applied were equivalent to raise in half; one; one and half; and twice the dose to elevate percentage of base saturation = 50%, corresponding to the 0; 0.45; 0.90; 1.35 and 1.80 g per pot, respectively, besides a control without application. The experimental unit was constituted of pots with 2 dm³ of a

  11. USE OF LOCAL NATURAL SILICEOUS RAW MATERIAL AND WASTES FOR PRODUCTION OF HEAT-INSULATING FOAMCONCRETE

    Directory of Open Access Journals (Sweden)

    V. U. Matsapulin

    2015-01-01

    Full Text Available The article analyzes the resource base, reserves and the use of siliceous rocks, their economic feasibility of the use for production of building materials of new generation with low-energy and other costs. Presented are the results of laboratory research and testing technology of production of insulating foam from a composition based on an aqueous solution of sodium silicate obtained from the local siliceous rocks (diatomite and the liquid alkali component - soapstock, hardener from ferrochrome slag and waste carbonate rock able to harden at a low temperature processing ( 100-110 ° C.

  12. Quantification of temporal changes in calcium score in active atherosclerotic plaque in major vessels by {sup 18}F-sodium fluoride PET/CT

    Energy Technology Data Exchange (ETDEWEB)

    Ishiwata, Yoshinobu; Kaneta, Tomohiro; Nawata, Shintaro; Hino-Shishikura, Ayako; Yoshida, Keisuke; Inoue, Tomio [Yokohama City University, Graduate School of Medicine, Department of Radiology, Yokohama, Kanagawa (Japan)

    2017-08-15

    Our aim was to assess whether {sup 18}F-NaF PET/CT is able to predict progression of the CT calcium score. Between August 2007 and November 2015, 34 patients (18 women, 16 men; age, mean ± standard deviation, 57.5 ± 13.9 years; age range 19-78 years) with malignancy or orthopaedic disease were enrolled in this study, with approximately 1-year follow-up data. Baseline and follow-up CT images were retrospectively evaluated for the presence of calcification sites in major vessel walls. The maximum and mean CT values (CTmax and CTmean, in Hounsfield units), calcification volumetric score (CVS, in cubic millimetres) and Agatston units score (AU) were evaluated for each site. Subsequent changes in CTmax, CTmean, CVS and AU were calculated and expressed as ΔCTmax, ΔCTmean, ΔCVS and ΔAU, respectively. We then evaluated the relationship between {sup 18}F-NaF uptake (using the maximum target-to-background ratio, TBRmax, and the maximum blood-subtracted {sup 18}F-NaF activity, bsNaFmax, which was obtained by subtracting the SUVmax of each calcified plaque lesion and NaF-avid site from the SUVmean in the right atrium blood pool) and the change in calcified plaque volume and characteristics obtained after 1 year. We detected and analysed 182 calcified plaque sites and 96 hot spots on major vessel walls. {sup 18}F-NaF uptake showed very weak correlations with CTmax, CTmean, CVS, CVS after 1 year, AU and AU after 1 year on both baseline and follow-up PET/CT scans for each site. {sup 18}F-NaF uptake showed no correlation with ΔCTmax or ΔCTmean. However, there was a significant correlation between the intensity of {sup 18}F-NaF uptake and ΔCVS and ΔAU. {sup 18}F-NaF uptake has a strong correlation with calcium score progression which was a predictor of future cardiovascular disease risk. PET/CT using {sup 18}F-NaF may be able to predict calcium score progression which is known to be the major characteristic of atherosclerosis. (orig.)

  13. Determination of the physiological plasmatic values of sodium, potassium and ion calcium and its pre and post exercise Variations in “paso fino” horses in the bogota savannah

    Directory of Open Access Journals (Sweden)

    Camila Valdés Restrepo

    2010-12-01

    Full Text Available This research intends to be a contribution to the Colombian sports equine medicine by providing data on electrolytes standards, a field where there is a substantial lack of literature. This research analyze and determines the normal values of sodium (Na+,potassium (K+ and ion calcium (iCa2+ electrolytes for Colombian Paso Fine horses. The establishment of the reference intervals was done at rest and after exercise. To achieve this, blood samples were taken from farms located in the Bogotá savannah. The 115 mares and stallions used for this study were actively competing with ages ranging from 43 to 78 months old. The samples were taken at three intervals: T0 (Rest,T1 (immediately after 45 minutes of exercise, and T2(1 hour post exercise. The samples were processed using a portable blood analyzer i-STAT® and the data was interpreted using descriptive and comparative statistic according to Turkey tests. The normal values for the breed were established and an electrolytic behavior curve was created, using values inside interval sat 95% confidence levels. The values obtained inmEq/L were: for T0: Na+ (136,71+/-0,23, K+ (4,05+/-0,03, Ca2+ (1,58+/-0,006; for T1: Na+ (136,44+/-0,24, K+ (3,92+/-0,24, Ca2+ (1,42+/-0,008; and for T2: Na+ (137,32+/-0,23, K+ (3,68+/-0,03, Ca2+(1,51+/-0,009. Na+ values increased after exercise. On the contrary K+ and Ca2+ values didn’t increase inT1. Calcium increased on T2 and K+ decreased. The findings of this research will serve as a framework for future analysis. Moreover, further studies and developments in this field are recommended and will prove to be very useful for equine practitioners.

  14. Environmental silicate nano-biocomposites

    CERN Document Server

    Pollet, Eric

    2012-01-01

    Environmental Silicate Nano-Biocomposites focuses on nano-biocomposites, which are obtained by the association of silicates such as bioclays with biopolymers. By highlighting recent developments and findings, green and biodegradable nano-composites from both renewable and biodegradable polymers are explored. This includes coverage of potential markets such as packaging, agricultures, leisure and the fast food industry. The knowledge and experience of more than twenty international experts in diverse fields, from chemical and biochemical engineering to applications, is brought together in four different sections covering: Biodegradable polymers and Silicates, Clay/Polyesters Nano-biocomposites, Clay/Agropolymers Nano-biocomposites, and Applications and biodegradation of Nano-biocomposites. By exploring the relationships between the biopolymer structures, the processes, and the final properties Environmental Silicate Nano-Biocomposites explains how to design nano-materials to develop new, valuable, environmenta...

  15. Investigation of the hydration and bioactivity of radiopacified tricalcium silicate cement, Biodentine and MTA Angelus.

    Science.gov (United States)

    Camilleri, Josette; Sorrentino, François; Damidot, Denis

    2013-05-01

    Novel root-end filling materials are composed of tricalcium silicate (TCS) and radiopacifier as opposed to the traditional mineral trioxide aggregate (MTA) which is made up of clinker derived from Portland cement and bismuth oxide. The aim of this research was to characterize and investigate the hydration of a tricalcium silicate-based proprietary brand cement (Biodentine™) and a laboratory manufactured cement made with a mixture of tricalcium silicate and zirconium oxide (TCS-20-Z) and compare their properties to MTA Angelus™. The materials investigated included a cement containing 80% of TCS and 20% zirconium oxide (TCS-20-Z), Biodentine™ and MTA Angelus™. The specific surface area and the particle size distribution of the un-hydrated cements and zirconium oxide were investigated using a gas adsorption method and scanning electron microscopy. Un-hydrated cements and set materials were tested for mineralogy and microstructure, assessment of bioactivity and hydration. Scanning electron microscopy, X-ray energy dispersive analysis, X-ray fluorescence spectroscopy, X-ray diffraction, Rietveld refined X-ray diffraction and calorimetry were employed. The radiopacity of the materials was investigated using ISO 6876 methods. The un-hydrated cements were composed of tricalcium silicate and a radiopacifier phase; zirconium oxide for both Biodentine™ and TCS-20-Z whereas bismuth oxide for MTA Angelus™. In addition Biodentine™ contained calcium carbonate particles and MTA Angelus™ exhibited the presence of dicalcium silicate, tricalcium aluminate, calcium, aluminum and silicon oxides. TCS and MTA Angelus™ exhibited similar specific surface area while Biodentine™ had a greater specific surface area. The cements hydrated and produced some hydrates located either as reaction rim around the tricalcium silicate grain or in between the grains at the expense of volume containing the water initially present in the mixture. The rate of reaction of tricalcium

  16. Calcium Carbonate

    Science.gov (United States)

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

  17. 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 ...

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

    Science.gov (United States)

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

    2014-01-01

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

  19. Effects of Sodium Chloride, Potassium Chloride and Calcium Chloride on the Formation of α-Dicarbonyl Compounds, Furfurals and Development of Browning in Cookies during Baking.

    Science.gov (United States)

    Kocadağlı, Tolgahan; Gökmen, Vural

    2016-10-02

    Effect of NaCl, KCl, CaCl2, NaHCO3, and NH4HCO3 on the formation of glucosone, 1-deoxyglucosone, 3-deoxyglucosone, glyoxal, methylglyoxal, diacetyl, 5-hydroxymethyl-2-furfural, 2-furfural and browning were investigated in cookies. Presence of 1.5% NaCl, 1% KCl, and 1% CaCl2 on flour basis had no effect on α-dicarbonyl compounds, except 1-deoxyglucosone increased in the presence of KCl and CaCl2. The increase in 5-hydroxymethyl-2-furfural formation in the presence of NaCl, KCl, and CaCl2 did not relate to 3-deoxyglucosone formation and pH changes. NaCl, KCl, and CaCl2 increased browning in cookies. Model reaction systems indicated that NaCl, KCl, and CaCl2 enhance browning by increasing furfurals in caramelization. NaCl, KCl, and CaCl2 decreased browning intensity in heated glucose-glycine system. Usage of CaCl2 in cookies may considerably increase furfurals but not α-dicarbonyl compounds. Sodium reduction can be obtained by replacement with potassium without sacrificing the desired consequences of caramelization in sugar rich bakeries.

  20. 21 CFR 184.1721 - Sodium acetate.

    Science.gov (United States)

    2010-04-01

    ... synthetically by the neutralization of acetic acid with sodium carbonate or by treating calcium acetate with...(n)(43) of this chapter. (e) Prior sanctions for this ingredient different from the uses established...

  1. Comparative evaluation of calcium hypochlorite and sodium hypochlorite associated with passive ultrasonic irrigation on antimicrobial activity of a root canal system infected with Enterococcus faecalis: an in vitro study.

    Science.gov (United States)

    de Almeida, Ana Paula; Souza, Matheus Albino; Miyagaki, Daniela Cristina; Dal Bello, Yuri; Cecchin, Doglas; Farina, Ana Paula

    2014-12-01

    The purpose of this study was to compare in vitro the effectiveness of calcium hypochlorite (Ca[OCl]2) and sodium hypochlorite (NaOCl) associated with passive ultrasonic irrigation in root canals of bovine teeth infected with Enterococcus faecalis. The root canals of 60 single-rooted bovine extracted teeth were enlarged up to a file 45, autoclaved, inoculated with Enterococcus faecalis, and incubated for 30 days. The samples were divided into 6 groups (n = 10) according to the protocol for decontamination: G1: no treatment; G2: distilled water; G3: 2.5% NaOCl; G4: 2.5% Ca(OCl)2; G5: 2.5% NaOCl with ultrasonic activation; and G6: 2.5% Ca(OCl)2 with ultrasonic activation (US). Microbiological testing (colony-forming unit [CFU] counting) was performed to evaluate and show, respectively, the effectiveness of the proposed treatments. Data were subjected to 1-way analysis of variance followed by the post hoc Tukey test (α = 0.05). Groups 1 and 2 showed the highest mean contamination (3.26 log10 CFU/mL and 2.69 log10 CFU/mL, respectively), which was statistically different from all other groups (P irrigation can aid in chemomechanical preparation, contributing in a significant way to the reduction of microbial content during root canal treatment. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  2. Mechanical and microstructural characterization of geopolymer synthesized from low calcium fly ash

    Directory of Open Access Journals (Sweden)

    Kramar Sabina

    2015-01-01

    Full Text Available This study deals with the mechanical and microstructural characterization of geopolymers synthesized from locally available fly ash. A low calcium fly ash was activated using a sodium silicate solution. Samples were characterized by means of flexural and compressive tests, Fourier Transform Infrared (FTIR spectroscopy, X-ray powder diffraction (XRD, and scanning electron microscopy (SEM. Porosity and pore size distributions were identified using mercury intrusion porosimetry and gas sorption. The compressive strength of the produced geopolymers, which is in the range of 1.6 to 53.3 N/mm2, is strongly related to the water content as well as SiO2/Na2O mass ratio of an alkali activator. The compressive strength significantly increased with decreases in the water content and increased silicon concentration used for the synthesis of geopolymers.

  3. Icariin, a Novel Blocker of Sodium and Calcium Channels, Eliminates Early and Delayed Afterdepolarizations, As Well As Triggered Activity, in Rabbit Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Wanzhen Jiang

    2017-05-01

    Full Text Available Icariin, a flavonoid monomer from Herba Epimedii, has confirmed pharmacological and biological effects. However, its effects on arrhythmias and cardiac electrophysiology remain unclear. Here we investigate the effects of icariin on ion currents and action potentials (APs in the rabbit myocardium. Furthermore, the effects of icariin on aconitine-induced arrhythmias were assessed in whole rabbits. Ion currents and APs were recorded in voltage-clamp and current-clamp mode in rabbit left ventricular myocytes (LVMs and left atrial myocytes (LAMs, respectively. Icariin significantly shortened action potential durations (APDs at 50 and 90% repolarization (APD50 and APD90 and reduced AP amplitude (APA and the maximum upstroke velocity (Vmax of APs in LAMs and LVMs; however, icariin had no effect on resting membrane potential (RMP in these cells. Icariin decreased the rate-dependence of the APD and completely abolished anemonia toxin II (ATX-II-induced early afterdepolarizations (EADs. Moreover, icariin significantly suppressed delayed afterdepolarizations (DADs and triggered activities (TAs elicited by isoproterenol (ISO, 1 μM and high extracellular calcium concentrations ([Ca2+]o, 3.6 mM in LVMs. Icariin also decreased INaT in a concentration-dependent manner in LAMs and LVMs, with IC50 values of 12.28 ± 0.29 μM (n = 8 cells/4 rabbits and 11.83 ± 0.92 μM (n = 10 cells/6 rabbits; p > 0.05 vs. LAMs, respectively, and reversed ATX-II-induced INaL in a concentration-dependent manner in LVMs. Furthermore, icariin attenuated ICaL in a dose-dependent manner in LVMs. The corresponding IC50 value was 4.78 ± 0.89 μM (n = 8 cells/4 rabbits, indicating that the aforementioned current in LVMs was 2.8-fold more sensitive to icariin than ICaL in LAMs (13.43 ± 2.73 μM; n = 9 cells/5 rabbits. Icariin induced leftward shifts in the steady-state inactivation curves of INaT and ICaL in LAMs and LVMs but did not have a significant effect on their activation

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

    Science.gov (United States)

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

    2002-09-15

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

  5. Sodium Test

    Science.gov (United States)

    ... low levels of cortisol, aldosterone and sex hormones ( Addison disease ) Drinking too much water as might occur during ... urinary sodium levels may indicate diuretic use or Addison disease. Sodium levels are often evaluated in relation to ...

  6. 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

    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...

  7. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette; Krøyer, Hanne

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates...... is that the cement paste structure and porosity can be engineered by addition of selected layer silicates having specific particle shapes and surface properties (e.g., charge and specific surface area). This seems to be due to the growth of calcium-silicate hydrates (C-S-H) on the clay particle surfaces......), surface charge, and size (micron and nano). The structure of the resulting cement pastes and mortars has been investigated by atomic force microscopy (AFM), helium porosimetry, nitrogen adsorption (specific surface area and porosity), low-temperature calorimetry (LTC) and thermal analysis. The main result...

  8. Bilateral urinary calculi after treatment with a silicate-containing milk thickener.

    Science.gov (United States)

    Ulinski, Tim; Sabot, Jean-François; Bourlon, Isabelle; Cochat, Pierre

    2004-04-01

    Nephrocalcinosis and/or urinary calculi are rare in infants. Furosemide treatment during the neonatal period, vitamin D intoxication, hereditary diseases such as hyperoxaluria or distal tubular acidosis are among the most common aetiologies. We report the case of a 6-month-old boy with an extra-hepatic biliary duct atresia treated by the Kasai procedure and a gastro-oesophageal reflux treated with a silicate containing milk thickener (Gelopectose, 5.5% colloidal silicate) since the neonatal period. He did not present any other endogenous risk factor for urinary stone formation (normal urinary calcium/creatinine ratio; normal urinary magnesium excretion). The nephrolithiasis was discovered as the boy presented painful episodes of macroscopic haematuria. Ultrasound examination revealed bilateral nephrocalcinosis and multiple bilateral calculi without infection or urinary obstruction. Infrared spectroscopy revealed silicate as the major component suggesting silicate absorption to be responsible for the described symptoms. After replacement of the silicate-containing agent by a silicate-free milk thickener, the lesions were completely reversible as confirmed by repeated renal ultrasound examinations over a 2-month period. Silicate-containing milk thickeners can be responsible for urinary calculi and/or nephrocalcinosis.

  9. Carbon Mineralization Using Phosphate and Silicate Ions

    Science.gov (United States)

    Gokturk, H.

    2013-12-01

    Carbon dioxide (CO2) reduction from combustion of fossil fuels has become an urgent concern for the society due to marked increase in weather related natural disasters and other negative consequences of global warming. CO2 is a highly stable molecule which does not readily interact with other neutral molecules. However it is more responsive to ions due to charge versus quadrupole interaction [1-2]. Ions can be created by dissolving a salt in water and then aerosolizing the solution. This approach gives CO2 molecules a chance to interact with the hydrated salt ions over the large surface area of the aerosol. Ion containing aerosols exist in nature, an example being sea spray particles generated by breaking waves. Such particles contain singly and doubly charged salt ions including Na+, Cl-, Mg++ and SO4--. Depending on the proximity of CO2 to the ion, interaction energy can be significantly higher than the thermal energy of the aerosol. For example, an interaction energy of 0.6 eV is obtained with the sulfate (SO4--) ion when CO2 is the nearest neighbor [2]. In this research interaction between CO2 and ions which carry higher charges are investigated. The molecules selected for the study are triply charged phosphate (PO4---) ions and quadruply charged silicate (SiO4----) ions. Examples of salts which contain such molecules are potassium phosphate (K3PO4) and sodium orthosilicate (Na4SiO4). The research has been carried out with first principle quantum mechanical calculations using the Density Functional Theory method with B3LYP functional and Pople type basis sets augmented with polarization and diffuse functions. Atomic models consist of the selected ions surrounded by water and CO2 molecules. Similar to the results obtained with singly and doubly charged ions [1-2], phosphate and silicate ions attract CO2 molecules. Energy of interaction between the ion and CO2 is 1.6 eV for the phosphate ion and 3.3 eV for the silicate ion. Hence one can expect that the selected

  10. Natural Weathering Rates of Silicate Minerals

    Science.gov (United States)

    White, A. F.

    2003-12-01

    Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic

  11. Hemograma, sódio, potássio, cálcio, osmolalidade e viscosidade durante angiocardiografia pediátrica com ioxaglato Blood cell count, sodium, potassium, calcium, osmolality and viscosity, during pediatric angiocardiography with ioxaglate

    Directory of Open Access Journals (Sweden)

    Mauro Regis Silva Moura

    1998-04-01

    Full Text Available OBJETIVO: Os meios de contraste (MC introduzem alterações em alguns parâmetros sangüíneos, adquirindo, assim, mais importância na angiocardiografia pediátrica. MÉTODOS: Estudamos a presença e a severidade das mudanças no hematócrito, hemoglobina, leucócitos, sódio, potássio, cálcio, osmolalidade e viscosidade, em 35 crianças submetidas a angiocardiografia com ioxaglato, identificando, também, as variáveis independentes responsáveis por essas alterações. As amostras sangüíneas foram colhidas no início do procedimento (S1, no fim (S2 e 2h após (S3. RESULTADOS: Hematócrito: S1= 47,3±6,9%; S2= 40,7±7,4% (pPURPOSE: Children's blood changes during angiocardiography may not be only due to the contrast media (CM. METHODS: We studied the presence and severity of changes in those parameters in 35 pediatric patients undergoing angiocardiography with ioxaglate aiming to identify independent variables responsible for those changes. Blood samples were taken at the beginning of the procedure (S1, at the end (S2 and two hours later (S3. RESULTS: Hematocrit: S1= 47.3±6.9%; S2= 40.7± 7.4% (p<0.001, (related to the CM volume r=0.37, p<0.05. Hemoglobin: S1= 15±2.1g%; S2= 13.2±2.4g% (p<0.001, and S3= 12.7±2.5g% (NS. White blood cell count: S1= 7940±3040 leukocytes/mm³; S2= 6950± 2700/mm³ (NS; S3= 10830±4690 leukocytes/mm³, (p<0.001. Procedure duration (r=0.38, p<0.05 and 5% glucose fluid given between S2 and S3 (r=0.49, p<0.05 were isolated. Sodium: S1= 134.5±0.4mEq/L; S2= 130.7±0.4mEq/L (p<0.001 (due to 5% glucose fluid injected, r=0.61, p<0.01. Potassium: S1= 4.22±0.45mEq/L, S2= 3.83±0.4mEq/L (p<0.001. Calcium: S1= 9.13± 1.03mg%; S2= 8.4±0.91mg/dL. (related to the CM, r=0.43, p<0.01. Osmolality: S1= 293.3±12.5mOsm/kg; S2= 300.6±13.3mOsm/kg (p<0.001. Viscosity: S1= 3.36±0.81; S2= 3.09±0.74 (p<0.01; S3= 3.87±0.89, p<0.001. There was an indirect linear regression with the CM. CONCLUSION: There were profound

  12. Battery components employing a silicate binder

    Science.gov (United States)

    Delnick, Frank M [Albuquerque, NM; Reinhardt, Frederick W [Albuquerque, NM; Odinek, Judy G [Rio Rancho, NM

    2011-05-24

    A battery component structure employing inorganic-silicate binders. In some embodiments, casting or coating of components may be performed using aqueous slurries of silicates and electrode materials or separator materials.

  13. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  14. Evaluation of Calcium Silicate Cement Bond Strength after Using ...

    African Journals Online (AJOL)

    2018-01-24

    Jan 24, 2018 ... Two‑way ANOVA analysis of variance and post hoc Tukey tests were used for analyses (P= 0.05). Results: The highest push‑out bond strength was observed in the Biodentine ..... Effect of blood contamination on the retention characteristics of two endodontic biomaterials in simulated furcation perforations.

  15. Developments in TEM Nanotomography of Calcium Silicate Hydrate

    KAUST Repository

    Taylor, Rae

    2015-04-01

    This investigation was designed to explore the possibility of using transmission electron microscope (TEM) tomography on cement-based systems gain a greater understanding of their nanostructure and pore network. The preliminary results show a clearly a well-defined pore network at the nanoscale, with pore size approximately 1.7-2.4 nm in diameter and spaced around 5-8 nm apart. A comparison of small angle X-ray scattering data with 2-D TEM images analyzed with the Fourier slice theorem documents an excellent structural correlation. © 2015 The American Ceramic Society.

  16. Modeling Nanomechanical Behavior of Calcium-Silicate-Hydrate

    Science.gov (United States)

    2012-08-01

    Figure 13. The indentation force versus indentation depth for specimens with packing ratios of 0.56, 0.64 and 0.74. The snap shots show the progression...Based on experimental data from Atomic Force Microscope (AFM; Nonat 2004), small angle neutron scattering (SANS; Allen et al. 2007), Transmission...ratios of 0.56, 0.64 and 0.74. The snap shots show the progression of indented particle assembly. The color shows the stresses in the vertical

  17. Processing and Properties of Chemically Derived Calcium Silicate Cements

    Science.gov (United States)

    1992-02-27

    alone due to the fineness of the powder and the stiffness of the dough which resulted after shear mixing, characterisitics consistent with the large...cements. The lamination of the polymer in the isostatically pressed cement samples could be the reason for high toughness results. Summary and

  18. Bioactivity and mineralization of hydroxyapatite with bioglass as sintering aid and bioceramics with Na{sub 3}Ca{sub 6}(PO{sub 4}){sub 5} and Ca{sub 5}(PO{sub 4}){sub 2}SiO{sub 4} in a silicate matrix

    Energy Technology Data Exchange (ETDEWEB)

    Demirkiran, Hande [Materials Science and Engineering Department, University of Texas at Arlington, Arlington, TX 76019 (United States); Mohandas, Arunesh; Dohi, Motokazi; Fuentes, Alonso; Nguyen, Kytai [Bioengineering Department, University of Texas at Arlington, Arlington, TX 76019 (United States); Aswath, Pranesh, E-mail: aswath@uta.edu [Materials Science and Engineering Department, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2010-01-30

    Hydroxyapatite and Bioglass-45S5 were sintered together creating new ceramic compositions that yielded increased apatite deposition and osteoblast differentiation and proliferation in vitro compared to hydroxyapatite. The sintered products characterized by X-ray diffraction, revealed hydroxyapatite as the main phase when small quantities (1, 2.5 and 5 wt.%) of bioglass was added. Bioglass behaved as a sintering aid with {beta}-TCP (Ca{sub 3}(PO{sub 4}){sub 2}) being the minor phase. The amount of {beta}-TCP increased with the amount of bioglass added. In compositions with larger additions of bioglass (10 and 25 wt.%), new phases with compositions of calcium phosphate silicate (Ca{sub 5}(PO{sub 4}){sub 2}SiO{sub 4}) and sodium calcium phosphate (Na{sub 3}Ca{sub 6}(PO{sub 4}){sub 5}) were formed respectively within amorphous silicate matrices. In vitro cell culture studies of the ceramic compositions were examined using bone marrow stromal cell (BMSC). Cell proliferation and differentiation of bone marrow stromal cells into osteoblasts were determined by Pico Green DNA assays and alkaline phosphatase (ALP) activity, respectively. All hydroxyapatite-bioglass co-sintered ceramics exhibited larger cell proliferation compared to pure hydroxyapatite samples. After 6 days in cell culture, the ceramic with Ca{sub 5}(PO{sub 4}){sub 3}SiO{sub 4} in a silicate matrix formed by reacting hydroxyapatite with 10 wt.% bioglass exhibited the maximum proliferation of the BMSC's. The ALP activity was found to be largest in the ceramic with Na{sub 3}Ca{sub 6}(PO{sub 4}){sub 5} embedded in a silicate matrix synthesized by reacting hydroxyapatite with 25 wt.% bioglass.

  19. Amended Silicated for Mercury Control

    Energy Technology Data Exchange (ETDEWEB)

    James Butz; Thomas Broderick; Craig Turchi

    2006-12-31

    Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where

  20. Alkali-metal silicate binders and methods of manufacture

    Science.gov (United States)

    Schutt, J. B. (Inventor)

    1979-01-01

    A paint binder is described which uses a potassium or sodium silicate dispersion having a silicon dioxide to alkali-metal oxide mol ratio of from 4.8:1 to 6.0:1. The binder exhibits stability during both manufacture and storage. The process of making the binder is predictable and repeatable and the binder may be made with inexpensive components. The high mol ratio is achieved with the inclusion of a silicon dioxide hydrogel. The binder, which also employs a silicone, is in the final form of a hydrogel sol.

  1. Sodium and Food Sources

    Science.gov (United States)

    ... Sources Top 10 Sources of Sodium How to Reduce Sodium Sodium Reduction Resources for Everyone Sodium Reduction Fact ... in processed food [PDF-867K] and how to reduce sodium. Sodium Reduction Is Challenging Types of food matter: ...

  2. Preparation and in vivo evaluation of a silicate-based composite bone cement.

    Science.gov (United States)

    Ma, Bing; Huan, Zhiguang; Xu, Chen; Ma, Nan; Zhu, Haibo; Zhong, Jipin; Chang, Jiang

    2017-08-01

    Silicate-based cements have been developed as a class of bioactive and biodegradable bone cements owing to their good in vitro bioactivity and ability to dissolve in a simulated body fluid. Until recently, however, the in vivo evidence of their ability to support bone regeneration is still scarce. In the present study, a pilot in vivo evaluation of a silicate-based composite bone cement (CSC) was carried out in a rabbit femur defect model. The cement was composed of tricalcium silicate, 45S5 bioglass and calcium sulfate, and the self-setting properties of the material were established. The in vivo bone integration and biodegradability of CSC were investigated and compared with those of bioactive glass particulates, and a calcium phosphate cement. The results showed that CSC underwent a relatively slower in vivo degradation as compared with bioactive glass and calcium phosphate cement. Histological observation demonstrated that bone contact area at the interface between the surrounding bone and CSC gradually increased with time proceeding. CSC kept its structural integrity during implantation in vivo because of its acceptable mechanical strength. These results provide evidence of effectiveness in vivo and suggest potential clinical applications of the silicate-based composite bone cements.

  3. Structure and aqueous reactivity of silicate glasses high-resolution nuclear magnetic resonance contribution; Structure et reactivite aqueuse des verres silicates apport de la resonance magnetique nucleaire haute-resolution

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, F

    2000-10-25

    This research aims at getting a better understanding of the relations which may exist between the chemical composition of the oxide silicate glasses, the structure and the aqueous reactivity. We study the cations present in most glasses, more particularly the radioactive waste glasses, and those which are more liable to bring information both about structure and reactivity. Among the experimental methods used, the nuclear magnetic resonance of multi-quantum magic-angle spinning (NMR MQ-MAS) has been carried out for the structural characterization of the pristine and altered glasses. In the first part, we discuss the possibility of deducting a type of information from a quantitative approach of the {sup 23}Na, {sup 27}Al and {sup 17}O NMR MQ-MAS. In the second part, we apply this method to glasses containing between two and six oxides. The vitreous compositions studied permit to focus our attention on the influence of sodium, aluminum and calcium on their local structural environment. We point out an evolution of the distributions of bond distances and angles in relation to the glass chemical composition. We show the strong potentiality of the {sup 17}O used to probe the pristine and altered glasses. The influence of the different cations studied on the rate of glass dissolution is debated from the alterations made on short periods. On the basis of all these data, we discuss the importance of the structural effect which may influence the kinetic phenomena of alteration. (author)

  4. Reduction-induced inward diffusion and crystal growth on the surfaces of iron-bearing silicate glasses

    DEFF Research Database (Denmark)

    Liu, S.J.; Tao, H.Z.; Zhang, Y.F.

    2015-01-01

    first and then the growth of silica crystals on the glass surface. The type of alkaline earth cations has a strong impact on both the glass transition and the surface crystallization. In the Mg-containing glass, a quartz layer forms on the glass surface. This could be attributed to the fact that Mg2......We investigate the sodium inward diffusion (i.e., sodium diffusion from surface toward interior) in iron containing alkaline earth silicate glasses under reducing conditions around Tg and the induced surface crystallization. The surface crystallization is caused by formation of a silicate-gel layer...

  5. Hidden Sodium

    Centers for Disease Control (CDC) Podcasts

    2013-03-04

    In this podcast, learn about reducing sodium intake by knowing what to eat and the main sources of sodium in the diet. It's important for a healthy lifestyle.  Created: 3/4/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/4/2013.

  6. In vitro bioactivity of a tricalcium silicate cement

    Energy Technology Data Exchange (ETDEWEB)

    Morejon-Alonso, L.; Bareiro, O.; Santos, L.A. dos, E-mail: loreley.morejon@ufrgs.b [Universidade Federal do Rio Grande do Sul (UFRG), Porto Alegre, RS (Brazil). Escola de Engenharia. Dep. de Materiais; Carrodeguas R, Garcia [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Ceramica y Vidrio. Dept. de Ceramica

    2009-07-01

    Tricalcium silicate is the major constituent of Portland cement and the responsible for their mechanical strength at early stages. In order to be used as and additive of conventional calcium phosphate cement (CPC), in vitro bioactivity of a calcium silicate cement (CSC) after soaking in simulated body fluid (SBF) for 14 days was study. The cement was obtained by mixing Ca{sub 3}SiO{sub 5}, obtained by sol-gel process, and a Na{sub 2}HPO{sub 4} solution. The morphological and structural changes of the material before and after soaking were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed the formation of a layer of a Hydroxyapatite (HA) onto the CSC cement after soaking for 1h in SBF that became denser with the increase of soaking time. The study suggests that Ca{sub 3}SiO{sub 5} would be an effective additive to improve the bioactivity and long term strength of conventional CPC. (author)

  7. Test of Anderson-Stuart model in sodium silicate glasses and the general Arrhenian conductivity rule in wide composition range Teste do modelo de Anderson-Stuart em vidros silicatos de sódio e a regra geral da condutividade de Arrhenius numa ampla faixa de composições

    Directory of Open Access Journals (Sweden)

    M. L. F. Nascimento

    2006-03-01

    Full Text Available We collected and analyzed literature data on ionic conductivity sigma and activation energy E A in the binary sodium silicate system in a wide composition range. The Anderson and Stuart model has been considered to describe the decreasing tendency of activation energy E A with alkali concentration in this system. In this analysis were considered experimental parameters, such as shear modulus G and relative dielectric permittivity epsilon. A general conductivity rule is found in 194 of 205 glasses, when one plots log sigma vs. E A/kB T, where kB is the Boltzmann constant and T is the absolute temperature. This fact means that the arrhenian relation has universal uniqueness of form sigma = sigma (E A,T in wide Na2O composition range. The results also show that there is strong correlation by more than 19 orders of magnitude on conductivity with E A/kBT. An explanation for this behavior links ionic conductivity and microscopic structure. The problem of phase separation in this system is also considered.Foram colecionados e analisados dados da literatura sobre condutividade iônica sigma e energia de ativação de condução E A, considerando o sistema binário silicato de sódio numa ampla faixa de composições. O modelo de Anderson e Stuart foi utilizado para descrever a tendência de decréscimo da energia de ativação EA com a concentração de álcalis neste sistema. Nesta análise foram considerados parâmetros experimentais tais como módulo de cisalhamento G e permissividade dielétrica relativa épsilon. Uma regra geral de condutividade foi observada em 194 de 205 vidros analisados quando se plota log sigma vs. E A/kB T, onde kB é a constante de Boltzmann e T é a temperatura absoluta. Isto significa que a relação de Arrhenius apresenta uma unicidade característica universal da forma sigma = sigma (E A,T numa ampla faixa de composições (Na2O. Os resultados também mostraram que há uma forte correlação, por mais de 19 ordens de

  8. Dietary sodium

    DEFF Research Database (Denmark)

    Graudal, Niels

    2015-01-01

    The 2013 Institute of Medicine (IOM) report "Sodium Intake in Populations: Assessment of Evidence" did not support the current recommendations of the IOM and the American Heart Association (AHA) to reduce daily dietary sodium intake to below 2,300 mg. The report concluded that the population......-based health outcome evidence was not sufficient to define a safe upper intake level for sodium. Recent studies have extended this conclusion to show that a