WorldWideScience

Sample records for calcium sulfate

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

    International Nuclear Information System (INIS)

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

  2. Calcium carbonate and calcium sulfate in Martian meteorite EETA79001

    Science.gov (United States)

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

    1987-01-01

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

  3. Immobilization of calcium sulfate contained in demolition waste

    International Nuclear Information System (INIS)

    This paper presents the results of a laboratory study undertaken to examine the treatment of demolition waste containing calcium sulfate by means of calcium sulfoaluminate clinker (CSA). The quantity of CSA necessary to entirely consume calcium sulfate was determined. Using infrared spectrometry analysis and X-ray diffraction, it was shown that calcium sulfate was entirely consumed when the ratio between CSA and calcium sulfate was 4. Standard sand was polluted by 4% calcium sulfate. Two solutions were investigated: ·either global treatment of sand by CSA, ·or immobilization of calcium sulfate by CSA, followed by the introduction of this milled mixture in standard sand. Regardless of the type of treatment, swelling was almost stabilized after 28 days of immersion in water

  4. Sulfate resistance of high calcium fly ash concrete

    Science.gov (United States)

    Dhole, Rajaram

    Sulfate attack is one of the mechanisms which can cause deterioration of concrete. In general, Class C fly ash mixtures are reported to provide poor sulfate resistance. Fly ashes, mainly those belonging to the Class C, were tested as per the ASTM C 1012 procedure to evaluate chemical sulfate resistance. Overall the Class C fly ashes showed poor resistance in the sulfate environment. Different strategies were used in this research work to improve the sulfate resistance of Class C fly ash mixes. The study revealed that some of the strategies such as use of low W/CM (water to cementing materials by mass ratio), silica fume or ultra fine fly ash, high volumes of fly ash and, ternary or quaternary mixes with suitable supplementary cementing materials, can successfully improve the sulfate resistance of the Class C fly ash mixes. Combined sulfate attack, involving physical and chemical action, was studied using sodium sulfate and calcium sulfate solutions. The specimens were subjected to wetting-drying cycles and temperature changes. These conditions were found to accelerate the rate of degradation of concrete placed in a sodium sulfate environment. W/CM was found to be the main governing factor in providing sulfate resistance to mixes. Calcium sulfate did not reveal damage as a result of mainly physical action. Characterization of the selected fly ashes was undertaken by using SEM, XRD and the Rietveld analysis techniques, to determine the relation between the composition of fly ashes and resistance to sulfate attack. The chemical composition of glass represented on the ternary diagram was the main factor which had a significant influence on the sulfate resistance of fly ash mixtures. Mixes prepared with fly ashes containing significant amounts of vulnerable crystalline phases offered poor sulfate resistance. Comparatively, fly ash mixes containing inert crystalline phases such as quartz, mullite and hematite offered good sulfate resistance. The analysis of hydrated lime

  5. SINTERING AND SULFATION OF CALCIUM SILICATE-ALUMINATE

    Science.gov (United States)

    The effect of sintering on the reactivity of solids at high temperature was studied. The nature of the interaction was studied with calcium silicate-aluminate reacting with SO2 between 665 and 800 C. The kinetics of the sintering and sulfation processes were measured independentl...

  6. Influence of the calcium sulfate source on the rheological behaviour of calcium sulfoaluminate cement pastes

    OpenAIRE

    Santacruz, Isabel; García-Maté, Marta; G. Aranda, Miguel Ángel; De la Torre, Ángeles G.

    2013-01-01

    Calcium sulfoaluminate (CSA) cements are receiving increasing attention since their manufacture produces much less CO2 than ordinary Portland cement (OPC) [1]. In addition, they show interesting properties such as high early-age strengths, short setting times and impermeability. The main uses of these CSA cements are for quick repairs and pre-cast products or floor concrete applications. They are prepared by mixing the clinker with different amounts of a calcium sulfate set regulator such as ...

  7. Study of calcium carbonate and sulfate co-precipitation

    KAUST Repository

    Zarga, Y.

    2013-06-01

    Co-precipitation of mineral based salts in scaling is still not well understood and/or thermodynamically well defined in the water industry. This study focuses on investigating calcium carbonate (CaCO3) and sulfate mixed precipitation in scaling which is commonly observed in industrial water treatment processes including seawater desalination either by thermal-based or membrane-based processes. Co-precipitation kinetics were studied carefully by monitoring several parameters simultaneously measured, including: pH, calcium and alkalinity concentrations as well as quartz microbalance responses. The CaCO3 germination in mixed precipitation was found to be different than that of simple precipitation. Indeed, the co-precipitation of CaCO3 germination time was not anymore related to supersaturation as in a simple homogenous precipitation, but was significantly reduced when the gypsum crystals appeared first. On the other hand, the calcium sulfate crystals appear to reduce the energetic barrier of CaCO3 nucleation and lead to its precipitation by activating heterogeneous germination. However, the presence of CaCO3 crystals does not seem to have any significant effect on gypsum precipitation. IR spectroscopy and the Scanning Electronic Microscopy (SEM) were used to identify the nature of scales structures. Gypsum was found to be the dominant precipitate while calcite and especially vaterite were found at lower proportions. These analyses showed also that gypsum crystals promote calcite crystallization to the detriment of other forms. © 2013 Elsevier Ltd.

  8. Thermodynamics and kinetics of the sulfation of porous calcium silicate

    Science.gov (United States)

    Miller, R. A.; Kohl, F. J.

    1981-01-01

    The sulfation of plasma sprayed calcium silicate in flowing SO2/air mixtures at 900 and 1000 C was investigated thermogravimetrically. Reaction products were analyzed using electron microprobe and X-ray diffraction analysis techniques, and results were compared with thermodynamic predictions. The percentage, by volume, of SO2 in air was varied between 0.036 and 10 percent. At 10 percent SO2 the weight gain curve displays a concave downward shoulder early in the sulfation process. An analytical model was developed which treats the initial process as one which decays exponentially with increasing time and the subsequent process as one which decays exponentially with increasing weight gain. At lower SO2 levels the initial rate is controlled by the reactant flow rate. At 1100 C and 0.036 percent SO2 there is no reaction, in agreement with thermodynamic predictions.

  9. Reactive Crystallization of Calcium Sulfate Dihydrate from Acidic Wastewater and Lime

    Institute of Scientific and Technical Information of China (English)

    邓立聪; 张亦飞; 陈芳芳; 曹绍涛; 游韶玮; 刘艳; 张懿

    2013-01-01

    The present work focused on the recycle of the sulfate and the metal ions from acidic wastewater dis-charged by nonferrous metallurgical industry. The effects of the temperature, the reactant concentration, the stirring speed and the metal ions on the reactive crystallization process of calcium sulfate between sulfuric acid and lime were systematically investigated. The morphology of the precipitated crystals evolved from platelet-like and nee-dle-like shape to rod-like shape when the temperature was increased from 25 to 70 °C. An increase in the agglom-eration of calcium sulfate was found with increasing lime concentration. Metal ions markedly retard the rate of crystallization of calcium sulfate dihydrate. The crystallization of gypsum was slowed with the existence of Mg2+in the solution, and the morphology of gypsum was transformed from platelet-like shape to rod-like shape when Mg2+concentration reached 0.08 mol·L-1. The amorphous ferric hydroxide was coated on the calcium sulfate after the co-precipitation process while Zn2+and Al3+ions in the solution enhanced the agglomeration of the calcium sulfate by absorbing on the surface of the crystals. Comprehensive acidic wastewater containing heavy metals was effi-ciently purified by the two stage lime neutralization technology, and highly agglomerated gypsum precipitates with needle-like shape were obtained. The precipitates could be purified by sulfuric acid washing, and the metal ions were effectively separated from the calcium sulfate by-products.

  10. Shape control synthesis of low-dimensional calcium sulfate

    Indian Academy of Sciences (India)

    Li-Xia Yang; Yan-Feng Meng; Ping Yin; Ying-Xia Yang; Ying-Ying Tang; Lai-Fen Qin

    2011-04-01

    Calcium sulfate nanorods, nanowires, nanobelts and sheets had been synthesized via a facile solution reaction of CaCl2 and H2SO4 in mixed solvents of ethanol/, -dimethylformamide and deionized water at 35°C. The results indicated that well-crystallized CaSO4 nanomaterials with different morphology were obtained by adjusting the volume ratio of ethanol/, -dimethylformamide to deionized water and the reaction time. Samples prepared at 35°C in mixed solvents of 50 mL ethanol and 30 mL water for 1 min and 2 h showed nanowire and sheet morphology, respectively. While increasing the volume ratio of ethanol to deionized water to 78/2, only nanorods were obtained. When , -dimethylformamide was employed to substitute ethanol, the sample heating at 35°C for 2 h was composed of nanowires in 50 mL , -dimethylformamide and 30 mL water. Higher volume ratio of , -dimethylformamide to deionized water caused the formation of nanorods.

  11. 21 CFR 524.1204 - Kanamycin sulfate, calcium amphomycin, and hydrocortisone acetate.

    Science.gov (United States)

    2010-04-01

    ... hydrocortisone acetate. 524.1204 Section 524.1204 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... DOSAGE FORM NEW ANIMAL DRUGS § 524.1204 Kanamycin sulfate, calcium amphomycin, and hydrocortisone acetate... activity as the calcium salt, and 10.0 milligrams of hydrocortisone acetate. (b) Sponsor. See No. 000856...

  12. Tailored sequential drug release from bilayered calcium sulfate composites

    Energy Technology Data Exchange (ETDEWEB)

    Orellana, Bryan R.; Puleo, David A., E-mail: puleo@uky.edu

    2014-10-01

    The current standard for treating infected bony defects, such as those caused by periodontal disease, requires multiple time-consuming steps and often multiple procedures to fight the infection and recover lost tissue. Releasing an antibiotic followed by an osteogenic agent from a synthetic bone graft substitute could allow for a streamlined treatment, reducing the need for multiple surgeries and thereby shortening recovery time. Tailorable bilayered calcium sulfate (CS) bone graft substitutes were developed with the ability to sequentially release multiple therapeutic agents. Bilayered composite samples having a shell and core geometry were fabricated with varying amounts (1 or 10 wt.%) of metronidazole-loaded poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography showed the overall layered geometry as well as the uniform distribution of PLGA within the shells. Dissolution studies demonstrated that the amount of PLGA particles (i.e., 1 vs. 10 wt.%) had a small but significant effect on the erosion rate (3% vs. 3.4%/d). Mechanical testing determined that introducing a layered geometry had a significant effect on the compressive strength, with an average reduction of 35%, but properties were comparable to those of mandibular trabecular bone. Sustained release of simvastatin directly loaded into CS demonstrated that changing the shell to core volume ratio dictates the duration of drug release from each layer. When loaded together in the shell or in separate layers, sequential release of metronidazole and simvastatin was achieved. By introducing a tunable, layered geometry capable of releasing multiple drugs, CS-based bone graft substitutes could be tailored in order to help streamline the multiple steps needed to regenerate tissue in infected defects. - Highlights: • Bilayered CS composites were fabricated as potential bone graft substitutes. • The shell

  13. Tailored sequential drug release from bilayered calcium sulfate composites

    International Nuclear Information System (INIS)

    The current standard for treating infected bony defects, such as those caused by periodontal disease, requires multiple time-consuming steps and often multiple procedures to fight the infection and recover lost tissue. Releasing an antibiotic followed by an osteogenic agent from a synthetic bone graft substitute could allow for a streamlined treatment, reducing the need for multiple surgeries and thereby shortening recovery time. Tailorable bilayered calcium sulfate (CS) bone graft substitutes were developed with the ability to sequentially release multiple therapeutic agents. Bilayered composite samples having a shell and core geometry were fabricated with varying amounts (1 or 10 wt.%) of metronidazole-loaded poly(lactic-co-glycolic acid) (PLGA) particles embedded in the shell and simvastatin directly loaded into either the shell, core, or both. Microcomputed tomography showed the overall layered geometry as well as the uniform distribution of PLGA within the shells. Dissolution studies demonstrated that the amount of PLGA particles (i.e., 1 vs. 10 wt.%) had a small but significant effect on the erosion rate (3% vs. 3.4%/d). Mechanical testing determined that introducing a layered geometry had a significant effect on the compressive strength, with an average reduction of 35%, but properties were comparable to those of mandibular trabecular bone. Sustained release of simvastatin directly loaded into CS demonstrated that changing the shell to core volume ratio dictates the duration of drug release from each layer. When loaded together in the shell or in separate layers, sequential release of metronidazole and simvastatin was achieved. By introducing a tunable, layered geometry capable of releasing multiple drugs, CS-based bone graft substitutes could be tailored in order to help streamline the multiple steps needed to regenerate tissue in infected defects. - Highlights: • Bilayered CS composites were fabricated as potential bone graft substitutes. • The shell

  14. Early C3A hydration in the presence of different kinds of calcium sulfate.

    OpenAIRE

    Pourchet, Sylvie; Regnaud, Laure; Perez, Jean-Philippe; Nonat, André

    2009-01-01

    Hydration reactions of C3A with various amounts of calcium sulfate hemihydrate, gypsum or a mixture of two, were investigated by isothermal microcalorimetry, and a monitoring of the ionic concentrations of diluted suspensions. This study shows that sulfate type used modifies the early C3A-CaSO4 hydration products and the rate of this hydration. The fast initial AFm formation observed before ettringite precipitation in the C3A-gypsum system is avoided as soon as hemihydrate is present in the s...

  15. Improved workability of injectable calcium sulfate bone cement by regulation of self-setting properties

    International Nuclear Information System (INIS)

    Calcium sulfate hemihydrate (CSH) powder as an injectable bone cement was prepared by hydrothermal synthesis of calcium sulfate dihydrate (CSD). The prepared materials showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from CSD phase to CSH phase. Thermogravimetric (TG) analyses showed the crystal water content of CSH was about 6.0% (wt.), which is near to the theoretic crystal water value of CSH. From scanning electron microscopy (SEM) micrographs, sheet crystal structure of CSD was observed to transform into rod-like crystal structure of CSH. Most interesting and important of all, CSD as setting accelerator was also introduced into CSH powder to regulate self-setting properties of injectable CSH paste, and thus the self-setting time of CSH paste can be regulated from near 30 min to less than 5 min by adding various amounts of setting accelerator. Because CSD is not only the reactant of preparing CSH but also the final solidified product of CSH, the setting accelerator has no significant effect on the other properties of materials, such as mechanical properties. In vitro biocompatibility and in vivo histology studies have demonstrated that the materials have good biocompatibility and good efficacy in bone regeneration. All these will further improve the workability of CSH in clinic applications. Highlights: ► Calcium sulfate hemihydrate (CSH) can be an injectable bone cement. ► CSH was produced by hydrothermal synthesis of calcium sulfate dihydrate (CSD). ► CSD was introduced into CSH powder to regulate self-setting properties of CSH. ► Setting accelerator has no significant effect on the other properties of materials. ► Injectable CSH has good biocompatibility and good efficacy in bone regeneration

  16. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    OpenAIRE

    A. A. Elisa; Ninomiya, S.; J. Shamshuddin; Roslan, I.

    2016-01-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the ma...

  17. New bone implant material with calcium sulfate and Ti modified hydroxyapatite

    OpenAIRE

    A. Ślósarczyk; J. Czechowska; Z. Paszkiewicz; A. Zima

    2010-01-01

    (TiHA) to develop a novel bone cement. Results of previous studies showed that bioactive potential of titanium modified hydroxyapatite ceramics is higher than that of pure HA. Calcium sulfate hemihydrate is also considered as a safe, biocompatible material, however it has been criticized for its rapid resorption. Combination of these materials may result in new cement type material with surgical handiness and selective resorption.Design/methodology/approach: TiHA was obtained by a wet method....

  18. The comparison between sulfate salt weathering of portland cement paste and calcium sulfoaluminate cement paste

    OpenAIRE

    Liu, Zanqun; Deng, Dehua; De Schutter, Geert

    2015-01-01

    In this paper, the damage performances of sulfate salt weathering of Portland cement paste and calcium sulfoaluminate (CSA) cement paste were compared according to authors' previous studies. It was found that the evaporation zone of speciments partially immersed in 10% Na2SO4 solution were both severely deteriorated for Portland cement and CSA cement. However, the differences were more significant: (1) the CSA cement paste were damaged just after 7 days exposure compared to the 5 months expos...

  19. Improved workability of injectable calcium sulfate bone cement by regulation of self-setting properties

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zonggang, E-mail: chenzg@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Huanye [Department of Orthodontics, School of Stomatology, China Medical University, Shenyang 110001 (China); Liu, Xi [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Lian, Xiaojie [College of Mechanics, Taiyuan University of Technology, Taiyuan 030024 (China); Guo, Zhongwu [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Jiang, Hong-Jiang [Wendeng Hospital of Traditional Chinese Orthopedics and Traumatology, Shandong 264400 (China); Cui, Fu-Zhai, E-mail: cuifz@mail.tsinghua.edu.cn [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2013-04-01

    Calcium sulfate hemihydrate (CSH) powder as an injectable bone cement was prepared by hydrothermal synthesis of calcium sulfate dihydrate (CSD). The prepared materials showed X-ray diffraction peaks corresponding to the CSH structure without any secondary phases, implying complete conversion from CSD phase to CSH phase. Thermogravimetric (TG) analyses showed the crystal water content of CSH was about 6.0% (wt.), which is near to the theoretic crystal water value of CSH. From scanning electron microscopy (SEM) micrographs, sheet crystal structure of CSD was observed to transform into rod-like crystal structure of CSH. Most interesting and important of all, CSD as setting accelerator was also introduced into CSH powder to regulate self-setting properties of injectable CSH paste, and thus the self-setting time of CSH paste can be regulated from near 30 min to less than 5 min by adding various amounts of setting accelerator. Because CSD is not only the reactant of preparing CSH but also the final solidified product of CSH, the setting accelerator has no significant effect on the other properties of materials, such as mechanical properties. In vitro biocompatibility and in vivo histology studies have demonstrated that the materials have good biocompatibility and good efficacy in bone regeneration. All these will further improve the workability of CSH in clinic applications. Highlights: ► Calcium sulfate hemihydrate (CSH) can be an injectable bone cement. ► CSH was produced by hydrothermal synthesis of calcium sulfate dihydrate (CSD). ► CSD was introduced into CSH powder to regulate self-setting properties of CSH. ► Setting accelerator has no significant effect on the other properties of materials. ► Injectable CSH has good biocompatibility and good efficacy in bone regeneration.

  20. Acidification of musts in warm regions with tartaric acid and calcium sulfate at industrial scale

    Directory of Open Access Journals (Sweden)

    Gómez Juan

    2015-01-01

    Full Text Available Acidification of musts is necessary in warm areas where high temperatures during ripening accelerate breathing com- bustion of tartaric acid and, in particular, malic acid in the berries. L(+ tartaric acid, L(- or D,L malic acid and lactic acids are the only chemical acidifiers authorized by the OIV and European Community regulations. The use of calcium sulfate (gypsum: CaSO4·2H2O is also authorized in the European Community as a complementary acidifier in generous and generous liquor 42 wines from Spain (a practice known as plastering, provided that the residual sulfate content in the wine does not exceed 2.5 g/L expressed as potassium sulfate. However, this practice is not yet approved by OIV. To predict the effect on pH of different acidi- fiers, several chemical modeling approaches have been described in the literature, in particular a simplified model where the acidity of wine is considered to be due to a monoprotic acid. The aim of this work is to verify this model at pilot and industrial scale in the acidification of musts with tartaric and calcium sulfate, added either individually and in combination, using doses up to 3 g/L and to study the modifications that these practices produce on the compositions of the resulting wines. This work sup- plies useful information to study this practice in OIV in order to consider its approval.

  1. Alleviating aluminum toxicity in an acid sulfate soil from Peninsular Malaysia by calcium silicate application

    Science.gov (United States)

    Elisa, A. A.; Ninomiya, S.; Shamshuddin, J.; Roslan, I.

    2016-03-01

    In response to human population increase, the utilization of acid sulfate soils for rice cultivation is one option for increasing production. The main problems associated with such soils are their low pH values and their associated high content of exchangeable Al, which could be detrimental to crop growth. The application of soil amendments is one approach for mitigating this problem, and calcium silicate is an alternative soil amendment that could be used. Therefore, the main objective of this study was to ameliorate soil acidity in rice-cropped soil. The secondary objective was to study the effects of calcium silicate amendment on soil acidity, exchangeable Al, exchangeable Ca, and Si content. The soil was treated with 0, 1, 2, and 3 Mg ha-1 of calcium silicate under submerged conditions and the soil treatments were sampled every 30 days throughout an incubation period of 120 days. Application of calcium silicate induced a positive effect on soil pH and exchangeable Al; soil pH increased from 2.9 (initial) to 3.5, while exchangeable Al was reduced from 4.26 (initial) to 0.82 cmolc kg-1. Furthermore, the exchangeable Ca and Si contents increased from 1.68 (initial) to 4.94 cmolc kg-1 and from 21.21 (initial) to 81.71 mg kg-1, respectively. Therefore, it was noted that calcium silicate was effective at alleviating Al toxicity in acid sulfate, rice-cropped soil, yielding values below the critical level of 2 cmolc kg-1. In addition, application of calcium silicate showed an ameliorative effect as it increased soil pH and supplied substantial amounts of Ca and Si.

  2. CALCIUM CARBONATE REDUCES IRON ABSORPTION FROM IRON SULFATE, BUT NOT WHEN IRON IS PRESENTED AS AN ORGANIC COMPLEX

    OpenAIRE

    E. C. CONCEI�O; Machado, A.A.; C. IZUMI; O. Freitas

    2008-01-01

    Experimental and epidemiological evidences have demonstrated that calcium inhibits iron absorption; calcium carbonate being one of the most effective calcium sources to reduce iron absorption from dietary origin or from iron sulfate. In the present work, the short-term effect of calcium from calcium carbonate on iron absorption was studied in rats, using different ir...

  3. Inhibition of the Crystal Growth and Aggregation of Calcium Oxalate by Algae Sulfated Polysaccharide In-vitro

    Institute of Scientific and Technical Information of China (English)

    Xiu Mei WU; Jian Ming OUYANG; Sui Ping DENG; Ying Zhou CEN

    2006-01-01

    The influence of sulfated polysaccharide (SPS) isolated from marine algae Sargassum fusiforme on the morphology and phase compositions of urinary crystal calcium oxalate was investigated in vitro by means of scanning electron microscopy and X-ray diffraction. SPS maybe is a potential inhibitor to CaOxa urinary stones by inhibiting the growth of calcium oxalate monohydrate (COM), preventing the aggregation of COM, and inducing the formation of calcium oxalate dihydrate (COD) crystals.

  4. The application status and advantages of calcium sulfate in dietary calcium%硫酸钙在膳食钙中的应用现状及优势

    Institute of Scientific and Technical Information of China (English)

    佘荆丽; 张杰; 黄明杰

    2014-01-01

    In the context of supplement of the calcium in China, nutritionists generally advice that people should sup-plement calcium through high calcium food, reduce supplement intake. In this paper, the substances relatively com-monly used in dietary were discussed. The four kinds of inorganic calcium salt discussed were calcium sulfate, calcium carbonate, calcium chloride, and calcium phosphate. It was concluded that natural, non-toxic, and high cost-efficiency calcium sulfate was the best in the application in dietary calcium.%中国式补钙的背后,国内外营养学界普遍建议,通过高钙食物来补充钙,减少补充剂摄入量。通过探讨在膳食中较为常用的硫酸钙、碳酸钙、氯化钙和磷酸钙4种无机钙盐在食品中的应用及其优缺点,最终认为天然、无毒、高性价比的硫酸钙在膳食钙的应用中更胜一筹。

  5. Calcium Sulfate with Stearic Acid as an Encouraging Carrier for Reindeer Bone Protein Extract

    Directory of Open Access Journals (Sweden)

    Pekka Jalovaara

    2011-07-01

    Full Text Available Various bone proteins and growth factors in specific concentrations are required for bone formation. If the body cannot produce sufficient quantities of these factors, bone trauma can be healed with an implant that includes the required factors in a carrier. This study was designed to evaluate various calcium salt candidates that can be used as carrier with reindeer bone protein extract to induce ectopic bone formation in the muscle pouch model of mouse. The bone protein extract was either impregnated into the disc form of carrier or mixed with carrier powder before implantation. The radiographic analysis indicated increased bone formation in all of the active groups containing the bone protein extract compared to the controls within 21 days follow-up. The highest bone formation was seen in the group with calcium sulfate with stearic acid where new bone and calcified cartilage were clearly visible. The greatest bone formation occurred in the groups that had bone protein extract readily available. This indicates that the bone forming factors in sufficient concentrations are required at the early stage of bone formation. The calcium sulfate with stearic acid was the most suitable and effective carrier for reindeer bone protein extract.

  6. Degradation of sulfated polysaccharide extracted from algal Laminaria japonica and its modulation on calcium oxalate crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang Jianming, E-mail: toyjm@jnu.edu.cn [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China); Wang Miao; Lu Peng; Tan Jin [Department of Chemistry, Jinan University, Guangzhou 510632 (China); Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou 510632 (China)

    2010-08-30

    Sulfated polysaccharide (LPS) extracted from alga Laminaria japonica was degraded by hydrogen peroxide (H{sub 2}O{sub 2}). The average molecular weight of LPS was apparently decreased from 172,000 to 9550 after degradation, while the proportion of sulfate groups (-OSO{sub 3}{sup -}) and carboxylic groups (-COO{sup -}) in the molecular chains of LPS were slightly decreased from 4.5% and 5.20% to 3.9% and 4.64%, respectively. The effects of degraded and natural LPS on formation of calcium oxalate (CaOxa) crystals were investigated in vitro using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), zeta-potential, and atomic absorption spectroscopy. LPS could increase the concentration of soluble Ca{sup 2+} ions in the solution, decrease the weight of precipitated CaOxa, and increase the negative value of zeta-potential of CaOxa crystals. LPS also inhibits the formation of thermodynamically stable calcium oxalate monohydrate (COM) crystals, while inducing and stabilizing metastable calcium oxalate dihydrate (COD) crystals. These results suggested that both degraded and natural LPS could decrease CaOxa crystallization, but the inhibition efficiency of the degraded LPS was clearly superior to that of the natural LPS. We expected this investigation would provide encouragement for further exploration into new drugs for the prevention and treatment of urolithiasis.

  7. Degradation of sulfated polysaccharide extracted from algal Laminaria japonica and its modulation on calcium oxalate crystallization

    International Nuclear Information System (INIS)

    Sulfated polysaccharide (LPS) extracted from alga Laminaria japonica was degraded by hydrogen peroxide (H2O2). The average molecular weight of LPS was apparently decreased from 172,000 to 9550 after degradation, while the proportion of sulfate groups (-OSO3-) and carboxylic groups (-COO-) in the molecular chains of LPS were slightly decreased from 4.5% and 5.20% to 3.9% and 4.64%, respectively. The effects of degraded and natural LPS on formation of calcium oxalate (CaOxa) crystals were investigated in vitro using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), zeta-potential, and atomic absorption spectroscopy. LPS could increase the concentration of soluble Ca2+ ions in the solution, decrease the weight of precipitated CaOxa, and increase the negative value of zeta-potential of CaOxa crystals. LPS also inhibits the formation of thermodynamically stable calcium oxalate monohydrate (COM) crystals, while inducing and stabilizing metastable calcium oxalate dihydrate (COD) crystals. These results suggested that both degraded and natural LPS could decrease CaOxa crystallization, but the inhibition efficiency of the degraded LPS was clearly superior to that of the natural LPS. We expected this investigation would provide encouragement for further exploration into new drugs for the prevention and treatment of urolithiasis.

  8. Fabrication of cefuroxime-impregnated calcium sulfate: Polycaprolactone composite implant for osteomyelitis

    Directory of Open Access Journals (Sweden)

    Gupta Himanshu

    2009-01-01

    Full Text Available Osteomyelitis is characterized as an inflammatory bone disease caused by pyrogenic bacteria. As oral bioavailabilities of antibiotics are low, a regimen of 6 weeks of intravenous antibiotic is necessary for adequate therapy. Although the dose of antibiotic administered systemically is high, therapeutically effective drug concentrations are not always achieved at the site of infection. This problem can be overcome by the use of local antibiotics from a biodegradable implant for chronic osteomyelitis that can deliver the drug at least for 6 weeks. The implant delivers high antibiotic concentration at tissue levels, obliterates dead space, aids bone repair and does not need to be removed. The aim of this study was to develop and evaluate a calcium sulfate and polycaprolactone (PCL-based composite biodegradable implantable delivery system of cefuroxime for the localized treatment of osteomyelitis that can deliver the drug for at least 6 weeks. The PCL and calcium sulfate composite system has not been studied yet. Interaction studies were carried out to check any incompatibility between the ingredients. Implants were prepared by a modified fabrication technique to avoid solvent use. The prepared implants were evaluated for various in vitro parameters like dimensions, hardness, tensile strength, drug release profile, sterility test and morphological changes in pellet before and after drug release. The pellets were also tested for microbiological efficacy and compared with a plain drug solution in different concentrations. Developed pellets are regular in shape and size with good tensile strength. The release profile displayed drug levels above the minimum inhibitory concentration continuously for up to 2 months. A wide zone of inhibition by the pellet against Staphylococcus aureus as compared with the drug solution proves its efficacy in the treatment of osteomyelitis. Results show that the developed calcium sulfate and PCL-based composite

  9. Magnesium and calcium sulfate stabilities and the water budget of Mars

    Science.gov (United States)

    Chou, I.-Ming; Seal, R.R., II

    2007-01-01

    Magnesium sulfate probably plays a dominant role in the water cycle of Mars away from the polar ice caps through hydration and dehydration reactions. This prominence is due to its abundance, its occurrence in numerous hydration states, and its ability to hydrate and dehydrate rapidly. New experimental studies on the metastable reaction between hexahydrite (MgSO4??6H2O) and starkeyite (MgSO4-4H2O) as a function of temperature and relative humidity, supplemented by recent investigations of the stable reaction between epsomite (MgSO4??7H2O) and hexahydrite and by phase equilibrium calculations, suggest that the most important magnesium sulfate phases involved in the Martian water cycle are MgSO4??11 H2O, epsomite, starkeyite, and possibly kieserite (MgSO4??H2O). Hexahydrite is not predicted to be stable on the surface of Mars. During diurnal variations in temperature and relative humidity, 1 kg of MgSO4 can release or remove from the atmosphere 1.5 kg of H2O by cycling between kieserite and MgSO4??11 H2O. Despite subequal abundances of calcium sulfate, calcium sulfates are not likely to be important in the water cycle of the planet because of sluggish rates of hydration and dehydration and a more limited range of H2O concentrations per kilogram of CaSO4 (0.00 to 0.26 kg kg-1). Modern or recent erosion on Mars attributed to liquid water may be due to the dehydration Of MgSO4??11 H2O because of the inferred abundance and likelihood of occurrence of this phase and its limited stability relative to known variations in temperature and relative humidity.

  10. Calcium sulfate combined with guided tissue regeneration: A novel technique in treatment of gingival recessions

    Science.gov (United States)

    Mukherji, Arnav

    2016-01-01

    The presence of mucogingival problem around anterior teeth is a challenge to the clinician as not only biological and functional aspects has to be addressed but esthetic aspirations of the patient have to be met. The use of guided tissue regeneration (GTR) procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance. However, maintenance of space under the membrane remains a problem for clinicians. Hence, this case study was an innovative attempt to evaluate the effect of adjunctive calcium sulfate placement along with collagen membrane GTR-based root coverage procedure. PMID:27307681

  11. Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars

    Science.gov (United States)

    Nachon, M.; Clegg, S. N.; Mangold, N.; Schroeder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.; LeMouelic, S.; Forni, O.; Wiens, R. C.; Rapin, W.; Anderson, R. B.; Blaney, D. L.; Bell, J. F. , III; Clark, B.; Cousin, A.; Dyar, M. D.; Ehlmann, B.; Fabre, C.; Gasnault, O.; Grotzinger, J.; Lasue, J.; Lewin, E.; Leveille, R.; McLennan, S.; Maurice, S.; Meslin, P.-Y.; Rice, M.; Squyres, S. W.; Stack, K.; Sumner, D. Y.; Vaniman, D.; Wellington, D.

    2014-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of :(1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of the targets [1;2] and (2) a Remote Micro Imager (RMI), for the imaging context of laser analysis [3]. Within the Gale crater, Curiosity traveled from Bradbury Landing through the Rocknest region and into Yellowknife Bay (YB). In the latter, abundant light-toned fracture-fill material were seen [4;5]. ChemCam analysis demonstrate that those fracture fills consist of calcium sulfates [6].

  12. Calcium Sulfate Characterized by Chemcam/Curiousity at Gale Crater, Mars

    Science.gov (United States)

    Nachon, M.; Clegg, S. M.; Mangold, N.; Schroeder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R; Oehler, D. Z.; Bridges, J. C.; LeMouelic, S.; Forni, O.; Wiens, R. C.; Anderson, R. B.; Blaney, D. L.; Bell, J. F., III; Clark, B.; Cousin, A.; Dyar, M. D.; Ehlmann, B.; Fabre, C.; Gasnault, O.; Grotzinger, J.; Lasue, J.; Stack, K.

    2014-01-01

    Onboard the Mars Science Laboratory (MSL) Curiosity rover, the ChemCam instrument consists of : (1) a Laser-Induced Breakdown Spectrometer (LIBS) for elemental analysis of the targets and (2) a Remote Micro Imager (RMI), for the imaging context of laser analysis. Within the Gale crater, Curiosity traveled from Bradbury Landing through the Rocknest region and into Yellowknife Bay (YB). In the latter, abundant light-toned fracture-fill material occur. ChemCam analysis demonstrates that those fracture fills consist of calcium sulfates.[

  13. CALCIUM CARBONATE REDUCES IRON ABSORPTION FROM IRON SULFATE, BUT NOT WHEN IRON IS PRESENTED AS AN ORGANIC COMPLEX

    Directory of Open Access Journals (Sweden)

    E. C. CONCEI�O

    2008-09-01

    Full Text Available

    Experimental and epidemiological evidences have demonstrated that calcium inhibits iron absorption; calcium carbonate being one of the most effective calcium sources to reduce iron absorption from dietary origin or from iron sulfate. In the present work, the short-term effect of calcium from calcium carbonate on iron absorption was studied in rats, using different iron compounds (monosodium ferric EDTA, iron-bys-glicine, iron peptide complex with iron sulfate as a control. Eighty (80 animals were divided into groups of 10 animals each with homogeneous weight. After 18h fast, the animals received by gavage 5 mL of a dispersion containing one of the iron compounds (1mg Fe/kg body weight, concomitantly or not with calcium carbonate at a molar ratio of 150:1 (Ca/Fe. Two hours after the administration, the animals were sacrificed and blood was collected for serum iron determination (iron transfer rate from intestinal lumen to blood compartment. Additionally, the intestines were collected for soluble iron determination (available iron. The results demonstrated that calcium ion from calcium carbonate inhibits the iron absorption from iron sulfate, but not from organic iron (di- or trivalent complexes.

  14. Enhancement of biodegradation and osseointegration of poly(ε-caprolactone)/calcium phosphate ceramic composite screws for osteofixation using calcium sulfate.

    Science.gov (United States)

    Wu, Chang-Chin; Hsu, Li-Ho; Tsai, Yuh-Feng; Sumi, Shoichiro; Yang, Kai-Chiang

    2016-04-01

    Internal fixation devices, which can stabilize and realign fractured bone, are widely used in fracture management. In this paper, a biodegradable composite fixator, composed of poly(ε-caprolactone), calcium phosphate ceramic and calcium sulfate (PCL/CPC/CS), is developed. The composition of CS, which has a high dissolution rate, was expected to create a porous structure to improve osteofixation to the composite fixator. PCL, PCL/CPC, and PCL/CPC/CS samples were prepared and their physical properties were characterized in vitro. In vivo performance of the composite screws was verified in the distal femurs of rabbits. Results showed that the PCL/CPC/CS composite had a higher compressive strength (28.55 ± 3.32 MPa) in comparison with that of PCL (20.64 ± 1.81 MPa) (p enhanced apatite formation of the PCL/CPC composite screw. This osteoconductive PCL/CPC/CS is a good candidate material for internal fixation devices. PMID:27041468

  15. Effect of calcium sulfates on the early hydration of calcium sulfoaluminate cement and the stability of embedded aluminium

    International Nuclear Information System (INIS)

    Conventional Portland cement-based systems have been considered unsuitable for immobilising nuclear wastes containing reactive metals, such as aluminium, due to the high pH of the pore solution (usually around 12.5) and free moisture. On the contrary, calcium sulfo-aluminate cement (CSA) produces a lower pH (10.5-12) environment and has an excellent water binding capability as a result of the formation of its main hydration product, ettringite. Therefore, it offers a good potential to immobilise aluminium. However, the pore solution pH and ettringite formation depend largely on the raw materials used to formulate the CSA, which is usually a blend of 75%-85% of CSA clinker and 15-25% of calcium sulfate (in the form of gypsum or anhydrite). In this paper, it was found that, compared to anhydrite, gypsum (15% wt of the blend) demonstrated the highest reduction in the corrosion of embedded Al, possibly due to its lower initial pH (around 10.5) and self-desiccating nature at the early stage of hydration. Whilst the CSA/anhydrite had a higher Al corrosion rate, the initial set was more acceptable than CSA/gypsum. Nonetheless, overall, it was concluded that CSA with gypsum (15% wt) should be considered as a base formulation for the encapsulation of Al waste. The unfavorable rapid set and high heat generation, however, demonstrated that modifications are required, potentially by using mineral additions. (authors)

  16. Synthesis and characterization of nanocrystalline calcium sulfate for use in osseous regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Bum; Dziak, Rosemary [Yonsei University College of Dentistry, 250 Seongsanno, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Mohan, Kathiravan [Advanced and Comfort Dentistry, 3655 Municipal Dr., Whitehall-Hokendauqua, PA 18052 (United States); Al-Sanousi, Abdulazi [Health Science Center, PO Box 24923, Safat 13110 (Kuwait); Almaghrabi, Bandar; Genco, Robert J [Department of Oral Biology, University at Buffalo (SUNY), 320 Foster Hall, South Campus, Buffalo, NY 14214 (United States); Swihart, Mark T, E-mail: rdziak@buffalo.edu [Department of Chemical and Biological Engineering, University at Buffalo (SUNY), 303 Furnas Hall, Buffalo, NY 14260-4200 (United States)

    2011-10-15

    Nanoparticles of calcium sulfate (nCS) have potential advantages as a ceramic matrix, scaffold and/or vehicle for delivering growth factors for osseous regeneration in a variety of clinical situations. The objectives of this study were to synthesize and characterize nanoparticles of hemihydrate calcium sulfate (nCS) and to develop a nCS-based system for bone regeneration. A cryo-vacuum method was used to process dihydrate CS into dihydrate nCS, which was then subjected to oven drying to produce hemihydrate. The nCS was sterilized by glow discharge treatment for use as a synthetic graft material for the treatment of bone defects. Electron microscopy showed that the nCS powder consisted of aggregates of closely arranged acicular crystals, approximately 30-80 nm in width, 400-600 nm in length and approximately 80-100 nm in diameter, providing a surface area about ten times that of conventional CS. Thorough physico-chemical characterization confirmed the composition and phase of the material. Cell viability/metabolic activity assays and alkaline phosphate assays confirmed the safety and biocompatibility of nCS. Release kinetics for adsorbed platelet-derived growth factor and bone morphogenetic protein-2 (BMP-2) suggests that nCS may serve as an appropriate vehicle for slow release delivery of these agents. The studies presented here give evidence of the advantages of nCS as a scaffold to support osteoblastic cell activity.

  17. Ultrasonication assisted and surfactant mediated synergistic approach for synthesis of calcium sulfate nano-dendrites.

    Science.gov (United States)

    Bari, Sarang; Chatterjee, Aniruddha; Mishra, Satyendra

    2016-07-01

    Calcium sulfate (CaSO4) nano-dendrimers were fabricated successfully via ultrasonic irradiation method using calcium chloride [CaCl2] and ammonium per sulfate [(NH4)2SO4] as precursors in aqueous solution by using cetyl trimethyl ammonium bromide (CTAB) as chemical surfactants. Diffusion-induced branching growth mechanism (DIBGM), influenced with the action of head-group and hydrocarbon chain effect of cationic surfactants, was the backbone in the formation of CaSO4 nano-dendrites. Fourier Transform Infra-red Spectroscopy (FTIR), X-Ray powder Diffraction (XRD), Atomic Emission Spectroscopy (AES), Selected Area Electron Diffraction (SAED), Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive Spectroscopy (EDS), Dynamic Light Spectroscopy (DLS) and BET surface area analyzer were used to characterize the products. Results obtained were compared with conventional stirring method that proved the superiority of sonication method to obtain well-crystalline nanostructures. Also, surfactant concentration, sonication frequency and time were noticed as the critical factors to generate such absolute morphologies at nano-crystalline size. PMID:26964922

  18. Bioactive calcium sulfate/magnesium phosphate cement for bone substitute applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guangyong [Department of Orthopaedics, Taizhou Hospital of Zhejiang Province, Linhai Zhejiang, 317000 (China); Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Liu, Jianli [Trauma Center, Affiliated Hospital of Hainan Medical University, Haikou, Hainan, 570206 (China); Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo, Zhejiang, 315201 (China); Li, Fan; Pan, Zongyou; Ni, Xiao; Shen, Yue [Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Xu, Huazi, E-mail: spinexu@163.com [Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang, 325000 (China); Huang, Qing, E-mail: huangqing@nimte.ac.cn [Division of Functional Materials and Nanodevices, Ningbo Institute of Materials Technology and Engineering (NIMTE), Chinese Academy of Sciences (CAS), Ningbo, Zhejiang, 315201 (China)

    2014-02-01

    A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6–12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration. - Highlights: • The mechanical strength and degradation rate of CSMPC composites are discussed. • The CSMPC composites exhibited good bioactivity to form bone-like apatite. • The CSMPC composites also show good biocompatibility.

  19. Bioactive calcium sulfate/magnesium phosphate cement for bone substitute applications

    International Nuclear Information System (INIS)

    A novel calcium sulfate/magnesium phosphate cement (CSMPC) composite was prepared and studied in the present work. The physical properties including the phases, the microstructures, the setting properties and the compressive strengths of the CSMPCs were studied. The bio-performances of the CSMPCs were comprehensively evaluated using in vitro simulated body fluid (SBF) method and in vitro cell culture. The dependence of the physical and chemical properties of the CSMPC on its composition and microstructure was studied in detail. It is found that the CSMPC composites exhibited mediate setting times (6–12 min) compared to the calcium sulfate (CS) and the magnesium phosphate cement (MPC). They showed an encapsulation structure in which the unconverted hexagonal prism CSH particles were embedded in the xerogel-like MPC matrix. The phase compositions and the mechanical properties of the CSMPCs were closely related to the content of MPC and the hardening process. The CSMPCs exhibited excellent bioactivity and good biocompatibility to support the cells to attach and proliferate on the surface. The CSMPC composite has the potential to serve as bone grafts for the bone regeneration. - Highlights: • The mechanical strength and degradation rate of CSMPC composites are discussed. • The CSMPC composites exhibited good bioactivity to form bone-like apatite. • The CSMPC composites also show good biocompatibility

  20. Synthesis and characterization of nanocrystalline calcium sulfate for use in osseous regeneration

    International Nuclear Information System (INIS)

    Nanoparticles of calcium sulfate (nCS) have potential advantages as a ceramic matrix, scaffold and/or vehicle for delivering growth factors for osseous regeneration in a variety of clinical situations. The objectives of this study were to synthesize and characterize nanoparticles of hemihydrate calcium sulfate (nCS) and to develop a nCS-based system for bone regeneration. A cryo-vacuum method was used to process dihydrate CS into dihydrate nCS, which was then subjected to oven drying to produce hemihydrate. The nCS was sterilized by glow discharge treatment for use as a synthetic graft material for the treatment of bone defects. Electron microscopy showed that the nCS powder consisted of aggregates of closely arranged acicular crystals, approximately 30-80 nm in width, 400-600 nm in length and approximately 80-100 nm in diameter, providing a surface area about ten times that of conventional CS. Thorough physico-chemical characterization confirmed the composition and phase of the material. Cell viability/metabolic activity assays and alkaline phosphate assays confirmed the safety and biocompatibility of nCS. Release kinetics for adsorbed platelet-derived growth factor and bone morphogenetic protein-2 (BMP-2) suggests that nCS may serve as an appropriate vehicle for slow release delivery of these agents. The studies presented here give evidence of the advantages of nCS as a scaffold to support osteoblastic cell activity.

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

    International Nuclear Information System (INIS)

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

  2. Calcium Sulfate and Platelet-Rich Plasma make a novel osteoinductive biomaterial for bone regeneration

    Directory of Open Access Journals (Sweden)

    Intini Francesco E

    2007-03-01

    Full Text Available Abstract Background With the present study we introduce a novel and simple biomaterial able to induce regeneration of bone. We theorized that nourishing a bone defect with calcium and with a large amount of activated platelets may initiate a series of biological processes that culminate in bone regeneration. Thus, we engineered CS-Platelet, a biomaterial based on the combination of Calcium Sulfate and Platelet-Rich Plasma in which Calcium Sulfate also acts as an activator of the platelets, therefore avoiding the need to activate the platelets with an agonist. Methods First, we tested CS-Platelet in heterotopic (muscle and orthotopic (bone bone regeneration bioassays. We then utilized CS-Platelet in a variety of dental and craniofacial clinical cases, where regeneration of bone was needed. Results The heterotopic bioassay showed formation of bone within the muscular tissue at the site of the implantation of CS-Platelet. Results of a quantitative orthotopic bioassay based on the rat calvaria critical size defect showed that only CS-Platelet and recombinant human BMP2 were able to induce a significant regeneration of bone. A non-human primate orthotopic bioassay also showed that CS-Platelet is completely resorbable. In all human clinical cases where CS-Platelet was used, a complete bone repair was achieved. Conclusion This study showed that CS-Platelet is a novel biomaterial able to induce formation of bone in heterotopic and orthotopic sites, in orthotopic critical size bone defects, and in various clinical situations. The discovery of CS-Platelet may represent a cost-effective breakthrough in bone regenerative therapy and an alternative or an adjuvant to the current treatments.

  3. Sulfato de calcio: propiedades y aplicaciones clínicas Calcium sulfate: properties and clinical applications

    Directory of Open Access Journals (Sweden)

    J López

    2011-12-01

    Full Text Available Durante más de cien años el sulfato de calcio se ha distinguido de otros biomateriales, por ser uno de los materiales aloplásticos más simples y que presenta la más larga historia clínica como material sintético. Entre sus principales propiedades destacan que es de fácil obtención, capacidad de osteoconducción, es totalmente absorbible, no provoca reacciones de inflamación o antigénicas, fácil modelado y fuerza de compresión semejante al tejido óseo. Todas éstas características son necesarias para ser usado como sustituto óseo. Sin embargo, diferencias en la morfología y estructura de sus cristales, la porosidad, propiedades mecánicas y en la constitución química del sulfato de calcio puede alterar significativamente sus propiedades biológicas. El objetivo de la presente revisión es conocer las propiedades del sulfato de calcio y sus diferentes aplicaciones clínicas como sustituto óseo en procedimientos regenerativos.For over 100 years, the calcium sulfate has stood out from other biomaterials, for being one of the simplest alloplastic materials and having the longest history as synthetic material. It is readily available, has osteoconductive properties, is completely absorbed, does not cause inflammation or antigenic reactions, can be modeled to defect, has compressive strength similar to bone tissue and can be used as a vehicle for in situ release of chemotherapeutic agents. All these features are required to be used as a bone substitute. However, differences in morphology, crystal structure, porosity, mechanical properties and chemical constitution of calcium sulfate can significantly alter its biological properties. The aim of this study was to determine through a review of the literature, the properties of calcium sulfate and its various clinical applications as bone substitute in regenerative procedures.

  4. Laboratory studies of the corrosion of nickel-based alloys by pure calcium sulfate -- Influence of environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Pomeroy, M.J.; Farhat, A.; McHale, P. [Univ. of Limerick (Ireland). Dept. of Materials Science and Technology

    1998-12-31

    Several nickel-based alloys and for comparison purposes, iron- and cobalt-based alloys have been coated with 8--10{micro}m Analar calcium sulfate and exposed in three types of external environments at a temperature of 850 C. Results from experiments in which the coated coupons were totally immersed in lightly compacted Analar-grade calcium sulfate powder and exposed in air for 144 hours showed that they underwent sulfidation-oxidation corrosion. Control experiments with no coating resulted in the formation of oxides alone, confirming that the presence of a compact calcium sulfate overlay was crucial to the development of the conditions necessary to cause sulfidation-oxidation corrosion. Relative extents of corrosion for the alloys showed distinct similarities with those observed in pilot scale coal-fired fluidized bed combustion systems. This fact together with the observation that corrosion morphologies for the alloys tested were similar to those observed in operating systems, demonstrates that the laboratory test method developed in this work is a suitable screening test for alloys with suitable mechanical properties for this industrial application. Subsequent sets of experiments at the same temperature, in which coated coupon surfaces were exposed to a synthetic flue gas containing 0.2% by volume sulfur dioxide for 144 hours, gave results which showed that sulfur exhaustion from the coating did not occur in the air environment. Thus, corrosion morphologies and extents of corrosion for the two different environments were effectively the same. The effect of substoichiometric conditions on the corrosion of the coated alloys was investigated by immersing the coupons in a calcium sulfate covered with finely divided carbon to give a sulfate to carbon mole ratio of 1:2. After 24 hours exposure at 85O C, significant corrosion of the nickel-based alloys occurred. The greater degree of corrosive attack can be attributed to the high partial pressures of sulfur vapor which

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

    International Nuclear Information System (INIS)

    The influence of addictives on the hydrothermal formation of hemi-hydrate calcium sulfate (CaSO4·0.5H2O) whiskers were discussed in this paper, using CaCl2 and Na2SO4 as the reactants. The presence of NaCl, CaCl2 or Na2SO4 increased the concentrations of Ca2+ and SO42-, leading to the formation of CaSO4·0.5H2O whiskers with aspect ratio lower than 50. The one dimensional growth of CaSO4·0.5H2O whiskers was enhanced in water with no additives owing to the low super-saturation, leading to the formation of uniform whiskers with a length of 200-2000 μm and an aspect ratio higher than 100.

  6. Sulfate but not thiosulfate reduces calculated and measured urinary ionized calcium and supersaturation: implications for the treatment of calcium renal stones.

    Directory of Open Access Journals (Sweden)

    Allen Rodgers

    Full Text Available Urinary sulfate (SO4(2- and thiosulfate (S2O3(2- can potentially bind with calcium and decrease kidney stone risk. We modeled the effects of these species on the concentration of ionized calcium (iCa and on supersaturation (SS of calcium oxalate (CaOx and calcium phosphate (CaP, and measured their in vitro effects on iCa and the upper limit of stability (ULM of these salts.Urine data from 4 different types of stone patients were obtained from the Mayo Nephrology Clinic (Model 1. A second data set was obtained from healthy controls and hypercalciuric stone formers in the literature who had been treated with sodium thiosulfate (STS (Model 2. The Joint Expert Speciation System (JESS was used to calculate iCa and SS. In Model 1, these parameters were calculated as a function of sulfate and thiosulfate concentrations. In Model 2, data from pre- and post STS urines were analyzed. ULM and iCa were determined in human urine as a function of sulfate and thiosulfate concentrations.Calculated iCa and SS values for all calcium salts decreased with increasing sulfate concentration. Thiosulfate had no effect on these parameters. In Model 2, calculated iCa and CaOx SS increased after STS treatment, but CaP SS decreased, perhaps due to a decrease in pH after STS treatment. In confirmatory in vitro experiments supplemental sulfate, but not thiosulfate, significantly increased the calcium needed to achieve the ULM of CaP and tended to increase the oxalate needed to reach the ULM of CaOx. Sulfate also significantly decreased iCa in human urine, while thiosulfate had no effect.Increasing urinary sulfate could theoretically reduce CaOx and CaP stone risk. Although STS may reduce CaP stone risk by decreasing urinary pH, it might also paradoxically increase iCa and CaOx SS. As such, STS may not be a viable treatment option for stone disease.

  7. Application of acidic calcium sulfate and e-polylysine to pre-rigor beef rounds for reduction of pathogens

    Science.gov (United States)

    Foodborne illness continues to be a serious public health problem and is a major concern for the United States food industry. This study evaluated the effectiveness of warm solutions of acidic calcium sulfate (ACS), lactic acid (LA), episolon-polylysine (EPL), ACS plus EPL, and sterile distilled wa...

  8. Synthesis, characterization and in vitro study of magnetic biphasic calcium sulfate-bioactive glass

    International Nuclear Information System (INIS)

    Calcium sulfate-bioactive glass (CSBG) composites doped with 5, 10 and 20 mol% Fe were synthesized using quick alkali sol–gel method. X-ray diffraction (XRD) data of samples heated at 700 °C revealed the presence of anhydrite, while field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) characterization confirmed the formation of nano-sized CSBGs. The UV–vis studies confirmed that the main iron species in 5% Fe and 10% Fe doped CSBGs were tetrahedral Fe(III) whereas that in 20% Fe doped CSBG were extra-framework FeOx oligomers or iron oxide phases. Measurement of magnetic properties of the samples by vibrating sample magnetometer (VSM) showed very narrow hysteresis loop with zero coercivity and remanence for 10% Fe and 20% Fe doped CSBG, indicating that they are superparamagnetic in nature. All samples induced the formation of apatite layer with Ca/P ratio close to the stoichiometric HA in simulated body fluid (SBF) assessment. - Highlights: • Biphasic calcium sulphate-bioactive glass containing iron was prepared. • Composite bioglass was superparamagnetic in nature. • All samples promoted the growth of apatite layer with Ca/P close to 1.67

  9. Synthesis, characterization and in vitro study of magnetic biphasic calcium sulfate-bioactive glass

    Energy Technology Data Exchange (ETDEWEB)

    Goh, Yi-Fan; Akram, Muhammad; Alshemary, Ammar Z. [Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor, Darul Ta' zim (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor Darul Ta' zim (Malaysia)

    2015-08-01

    Calcium sulfate-bioactive glass (CSBG) composites doped with 5, 10 and 20 mol% Fe were synthesized using quick alkali sol–gel method. X-ray diffraction (XRD) data of samples heated at 700 °C revealed the presence of anhydrite, while field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDX) characterization confirmed the formation of nano-sized CSBGs. The UV–vis studies confirmed that the main iron species in 5% Fe and 10% Fe doped CSBGs were tetrahedral Fe(III) whereas that in 20% Fe doped CSBG were extra-framework FeO{sub x} oligomers or iron oxide phases. Measurement of magnetic properties of the samples by vibrating sample magnetometer (VSM) showed very narrow hysteresis loop with zero coercivity and remanence for 10% Fe and 20% Fe doped CSBG, indicating that they are superparamagnetic in nature. All samples induced the formation of apatite layer with Ca/P ratio close to the stoichiometric HA in simulated body fluid (SBF) assessment. - Highlights: • Biphasic calcium sulphate-bioactive glass containing iron was prepared. • Composite bioglass was superparamagnetic in nature. • All samples promoted the growth of apatite layer with Ca/P close to 1.67.

  10. A comparative study of calcium sulfate artificial bone graft versus allograft in the reconstruction of bone defect after tumor curettage

    Institute of Scientific and Technical Information of China (English)

    Yang Yongkun; Niu Xiaohui; Zhang Qing; Hao Lin; Ding Yi; Xu Hairong

    2014-01-01

    Background Cavity reconstruction after benign bone tumor removal is varied and controversial.AIIograft is widely used but is associated with complications.New bone substitutes,such as calcium sulfate artificial bone,have been introduced for bone tumor operation.However,the bone healing response of artificial bone has not been compared with allograft bone.We therefore compared calcium sulfate grafts (study group) with bone allografts (control group) for the treatment of benign bone tumors.Methods We retrospectively reviewed 50 patients who underwent calcium sulfate reconstruction and 50 patients who underwent allograft cancellous bone reconstruction.The two groups were well matched.The mean follow-up time of the study group was 19.9 (12-55) months.We investigated bone healing response,complications,and factors affecting bone healing.Results At the last follow-up,84% (42/50) of cases in the study group and 62% (31/50) of cases in the control group had achieved clinical healing (P=0.013).The initial healing rate showed no significant difference between the two groups (100% vs.96%,P=0.153).The mean healing times for calcium sulfate and allograft bone were 9.6 (3-42) months and 13.8 (3-36) months,respectively (P <0.01).Complications in the study group were minor and resolved.Implant volume was a significant factor affecting bone healing.Conclusion The calcium sulfate bone substitute showed a satisfactory healing outcome and safety profile in reconstruction of bone defects after benign bone tumor curettage,especially in smaller cavities.

  11. Biomechanical evaluation of vertebroplasty using calcium sulfate cement for thoracolumbar burst fractures

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-tao; JIANG Xing-jie; ZHANG Shao-dong; YANG Hui-lin

    2007-01-01

    Objective: To evaluate the biomechanical performance of vertebroplasty using calcium sulfate cement for thoracolumbar burst fractures.Methods: Sixteen bovine thoracolumbar spines (T11-L1 ) were divided into 4 groups (A, B, C and D). After burst-fracture model was created, 12 vertebral bodies in Groups A, B and C were augmented with calcium sulfate cement (CSC), calcium phosphate cement (CPC) and polymethylmethacrylate ( PMMA ) bone cement,respectively. Each anterior vertebral body height was measured with a caliper at 4 time points: intact conditions(HInt), post-fracture (HFr), post-reduction (HRe) and post-vertebroplasty (HVP). The filling volume of 3 different bone cements was also measured. Each vertebral body was compressed at 0.5 mm/s using a hinged plating system on a materials testing machine to 50% of the postvertebroplasty height to determine strength and stiffness.Difference was checked using t test or One-way ANOVA.Results: The average strike energy was 66. 2 J.Vertebroplasty with different cements could sustain vertebral height. The average filling volume of bone cement in 3 groups was 4.35 ml (CSC), 3.72 ml (CPC) and 3.95 ml (PMMA), respectively, and there was no statistically significant difference among them ( P >0.05).Vertebroplasty with PMMA completely restored strength(116%) and stiffness (105%). CSC or CPC partly recovered vertebral strength and stiffness. However,greater strength restoration was got with CSC ( 1 659 N) as compared with CPC (1 011N, P<0.01 ). Regarding stiffness, differences between CSC (140 N/mm ±40 N/mm)and the other two bone cements ( CPC :148 N/mm ±33 N/mm,PMMA:236 N/mm ±97 N/mm) were not significant (P>0.05).Conclusions: For a burst-fracture of calf spine, useof CSC for vertebroplasty yields similar vertebral stiffnessas compared with PMMA or CPC. Although augmentationwith CSC partly obtains the normal strength, thistreatment still can be applied in thoracolumbar burstfractures with other instrumental devices in

  12. New bone implant material with calcium sulfate and Ti modified hydroxyapatite

    Directory of Open Access Journals (Sweden)

    A. Ślósarczyk

    2010-11-01

    Full Text Available (TiHA to develop a novel bone cement. Results of previous studies showed that bioactive potential of titanium modified hydroxyapatite ceramics is higher than that of pure HA. Calcium sulfate hemihydrate is also considered as a safe, biocompatible material, however it has been criticized for its rapid resorption. Combination of these materials may result in new cement type material with surgical handiness and selective resorption.Design/methodology/approach: TiHA was obtained by a wet method. Three compositions with different CSH:TiHA weight ratios, namely 3:2, 2:3 and 1:4 were examined. Pure CSH was used as a reference. Distilled water and Na2HPO4 solutions were applied as liquid phases. The study presents the setting time (Gillmore apparatus, phase composition (XRD, microstructure (SEM, porosity (mercury porosimetry and compressive strength of the obtained new, cement type, implant material.Findings: Initial (I and final (F setting times of the obtained cements differed in the range of 2-16 min (I and 4-75 min (F. The phase composition of the hardened cement bodies characterized by XRD method revealed the presence of calcium sulfate dihydrate (CSD and hydroxyapatite. Scanning electron microscopy images show excellent bonding between needle-like CSD crystals and apatitic phase. Porosity of the final samples varied from 49 to 59% with pore size diameter from 5 nm to 3.0 μm. Compressive strength of the samples differed in the range of 3.81-7.58 MPa.Research limitations/implications: The obtained results suggest that CSH-TiHA cements have the potential to be applied in bone substitution and for delivery of drugs. Bioactivity and biodegradation of the studied materials should be checked.Originality/value: According to our knowledge, these are the first studies concerning surgical handiness of bone implant materials based on calcium sufate hemihydrate and titanium doped hydroxyapatite. The cement type composites are biocompatible, shapeable and easy

  13. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing

    Science.gov (United States)

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C–1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C–1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds

  14. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    Directory of Open Access Journals (Sweden)

    Mitra Asadi-Eydivand

    Full Text Available The ability of inkjet-based 3D printing (3DP to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat

  15. Structure, Properties, and In Vitro Behavior of Heat-Treated Calcium Sulfate Scaffolds Fabricated by 3D Printing.

    Science.gov (United States)

    Asadi-Eydivand, Mitra; Solati-Hashjin, Mehran; Shafiei, Seyedeh Sara; Mohammadi, Sepideh; Hafezi, Masoud; Abu Osman, Noor Azuan

    2016-01-01

    The ability of inkjet-based 3D printing (3DP) to fabricate biocompatible ceramics has made it one of the most favorable techniques to generate bone tissue engineering (BTE) scaffolds. Calcium sulfates exhibit various beneficial characteristics, and they can be used as a promising biomaterial in BTE. However, low mechanical performance caused by the brittle character of ceramic materials is the main weakness of 3DP calcium sulfate scaffolds. Moreover, the presence of certain organic matters in the starting powder and binder solution causes products to have high toxicity levels. A post-processing treatment is usually employed to improve the physical, chemical, and biological behaviors of the printed scaffolds. In this study, the effects of heat treatment on the structural, mechanical, and physical characteristics of 3DP calcium sulfate prototypes were investigated. Different microscopy and spectroscopy methods were employed to characterize the printed prototypes. The in vitro cytotoxicity of the specimens was also evaluated before and after heat treatment. Results showed that the as-printed scaffolds and specimens heat treated at 300°C exhibited severe toxicity in vitro but had almost adequate strength. By contrast, the specimens heat treated in the 500°C-1000°C temperature range, although non-toxic, had insufficient mechanical strength, which was mainly attributed to the exit of the organic binder before 500°C and the absence of sufficient densification below 1000°C. The sintering process was accelerated at temperatures higher than 1000°C, resulting in higher compressive strength and less cytotoxicity. An anhydrous form of calcium sulfate was the only crystalline phase existing in the samples heated at 500°C-1150°C. The formation of calcium oxide caused by partial decomposition of calcium sulfate was observed in the specimens heat treated at temperatures higher than 1200°C. Although considerable improvements in cell viability of heat-treated scaffolds were

  16. Effects of spermidine and calcium sulfate on quantitative and qualitative traits and vase life of rose (Rosa hybrida cv. Dolcvita grown in hydroponic system

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    M. Hosseini Farahi

    2013-07-01

    Full Text Available In order to improve quantitative and qualitative properties and vase life of rose cv. Dolcvita, an experiment was conducted in a randomized complete blocks design with ten treatments and three replications in a hydroponic greenhouse adjacent to Yasouj city, Iran. Treatments included control, spermidine (0.5, 1 and 1.5 mM, calcium sulfate (2.5 and 5 mM, spermidine 0.5 mM+ calcium sulfate 2.5 mM, spermidine 0.5 mM + calcium sulfate 5 mM, spermidine 1 mM + calcium sulfate 2.5 mM and spermidine 1 mM + calcium sulfate 5 mM. Traits such as length of flower stalk, stem diameter, flower bud diameter, fresh weight of stem, chlorophyll content and vase life were measured. Results showed that effect of spermidine and calcium sulfate on all traits, except chlorophyll content, was significant (P<0.05. The highest and lowest length of flower stalk, stem diameter and fresh weight of stem was obtained in the 1.5 mM spermidine and control treatments, respectively. The highest diameter of flower bud was observed in the 0.5 mM spermidine and 2.5 mM calcium sulfate treatments. Flower vase life in the 0.5 mM spermidine + 5 mM calcium sulfate treatment was higher than that in the other treatments. Therefore, application of 1.5 mM spermidine is recommended for improving quantitative properties and combination of 0.5 mM spermidine with 5 mM calcium sulfate for increasing vase life of rose, cultivar Dolcvita, in hydroponic system.

  17. Improvement of in vitro physicochemical properties and osteogenic activity of calcium sulfate cement for bone repair by dicalcium silicate

    International Nuclear Information System (INIS)

    Highlights: • Dicalcium silicate can improve osteogenic activity of calcium sulfate cement. • The higher the calcium sulfate content, the shorter the setting time in the composite cement. • The results were useful for designing calcium-based cement with optimal properties. -- Abstract: An ideal bone graft substitute should have the same speed of degradation as formation of new bone tissue. To improve the properties of calcium sulfate hemihydrate (CSH) featured for its rapid resorption, a low degradation material of dicalcium silicate (DCS) was added to the CSH cement. This study examined the effect of DCS (20, 40, 60 and 80 wt%) on the in vitro physicochemical properties and osteogenic activities of the calcium-based composite cements. The diametral tensile strength, porosity and weight loss of the composite cements were evaluated before and after soaking in a simulated body fluid (SBF). The osteogenic activities, such as proliferation, differentiation and mineralization, of human mesenchymal stem cells (hMSCs) seeded on cement surfaces were also examined. As a result, the greater the DCS amount, the higher the setting time was in the cement. Before soaking in SBF, the diametral tensile strength of the composite cements was decreased due to the introduction of DCS. On 180-day soaking, the composite cements containing 20, 40, 60 and 80 wt% DCS lost 80%, 69%, 61% and 44% in strength, respectively. Regarding in vitro bioactivity, the DCS-rich cements were covered with clusters of apatite spherulites after soaking for 7 days, while there was no formation of apatite spherulites on the CSH-rich cement surfaces. The presence of DCS could reduce the degradation of the CSH cements, as evidenced in the results of weight loss and porosity. More importantly, DCS may promote effectively the cell proliferation, proliferation and mineralization. The combination of osteogenesis of DCS and degradation of CSH made the calcium-based composite cements an attractive choice for

  18. A new acoustic method to determine the setting time of calcium sulfate bone cement mixed with antibiotics

    International Nuclear Information System (INIS)

    A new method is described which can be used to determine the setting times of small amounts of high value bone cements. The test was developed to measure how the setting times of a commercially available synthetic calcium sulfate cement (Stimulan, Biocomposites, UK) in two forms (standard and Rapid Cure) varies with the addition of clinically relevant antibiotics. The importance of being able to accurately quantify these setting times is discussed. The results demonstrate that this new method, which is shown to correlate to the Vicat needle, gives reliable and repeatable data with additional benefits expressed in the article. The majority of antibiotics mixed were found to retard the setting reaction of the calcium sulfate cement. (paper)

  19. Enhanced Stability of Calcium Sulfate Scaffolds with 45S5 Bioglass for Bone Repair

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    Cijun Shuai

    2015-11-01

    Full Text Available Calcium sulfate (CaSO4, as a promising tissue repair material, has been applied widely due to its outstanding bioabsorbability and osteoconduction. However, fast disintegration, insufficient mechanical strength and poor bioactivity have limited its further application. In the study, CaSO4 scaffolds fabricated by using selective laser sintering were improved by adding 45S5 bioglass. The 45S5 bioglass enhanced stability significantly due to the bond effect of glassy phase between the CaSO4 grains. After immersing for four days in simulated body fluid (SBF, the specimens with 45S5 bioglass could still retain its original shape compared as opposed to specimens without 45S5 bioglass who experienced disintegration. Meanwhile, its compressive strength and fracture toughness increased by 80% and 37%, respectively. Furthermore, the apatite layer was formed on the CaSO4 scaffolds with 45S5 bioglass in SBF, indicating good bioactivity of the scaffolds. In addition, the scaffolds showed good ability to support the osteoblast-like cell adhesion and proliferation.

  20. A Novel Injectable Magnesium/Calcium Sulfate Hemihydrate Composite Cement for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Shanchuan Zhang

    2015-01-01

    Full Text Available Objective. A novel injectable magnesium/calcium sulfate hemihydrate (Mg/CSH composite with improved properties was reported here. Methods. Composition, setting time, injectability, compressive strength, and bioactivity in simulated body fluid (SBF of the Mg/CSH composite were evaluated. Furthermore, the cellular responses of canine bone marrow stromal cells (cBMSCs and bone formation capacity after the implantation of Mg/CSH in tibia defects of canine were investigated. Results. Mg/CSH possessed a prolonged setting time and markedly improved injectability and mechanical property p<0.05. Mg/CSH samples showed better degradability than CSH in SBF after 21 days of soaking p<0.05. Moreover, the degrees of cell attachment, proliferation, and capability of osteogenic differentiation on the Mg/CSH specimens were higher than those on CSH, without significant cytotoxicity and with the increased proliferation index, ALP activity, and expression levels of integrin β1 and Coll I in cBMSCs p<0.05. Mg/CSH enhanced the efficiency of new bone formation at the tibia defect area, including the significantly elevated bone mineral density, bone area fraction, and Coll I expression level p<0.05. Conclusions. The results implied that this new injectable bone scaffold exhibited promising prospects for bone repair and had a great potential in bone tissue engineering.

  1. Thermal simulation experiments of saturated hydrocarbons with calcium sulfate and element sulfur: Implications on origin of H2S

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Temperature-programmed simulation experiments of saturated hydrocarbons with calcium sulfate and element sulfur were compared in this study. Based on the variation analysis of the yields and evolvement features of gaseous hydrocarbon (C1-C5) and inorganic gaseous CO2, H2 and H2S, the reaction mechanisms were analyzed and discussed. In the calcium sulfate-saturated hydrocarbon system, H2S was produced by a small quantity, which indicates this reaction belongs to the low-degreed thermal sulfate reduction (TSR) and is featured of self-pyrolysis. In the sulfur-saturated hydrocarbon system, the heated sulfur becomes sulfur radical, which has strong catalysis capability and can fasten the cracking of C―H bond in the alkyl group in the saturated hydrocarbons. As a result, the cracking of C―H bond leads to the yields enhancement of CO2 and H2, and at the same time, H2S was produced since the cracked hydrogen can be instantly combined with sulfur radical. Therefore, this reaction in the sulfur-hydrocarbon system belongs to the catalysis of sulfur radical. Furthermore, the promoted pyrolysis effects of C6+ hydrocarbons by sulfur radical in the low-temperature stage in the sul- fur-hydrocarbon system, together with the consumption effects of gaseous hydrocarbon in the high-temperature stage in the calcium-hydrocarbon system, result in the crossed phenomenon of the gaseous hydrocarbon yields curves.

  2. Thermoluminescent properties of lithium borate, magnesium borate and calcium sulfate developed for temperature sensing

    International Nuclear Information System (INIS)

    The objective of this work is to characterize three thermoluminescent (TL) materials synthesized in our laboratory and identified as having properties suitable for temperature sensing, including bright TL emission, low fading at room temperature and low light-induced fading (bleaching) of the TL signal. They are lithium borate doped with copper and silver, Li2B4O7:Cu,Ag (LBO), magnesium borate doped with dysprosium and lithium, MgB4O7:Dy,Li (MBO), and calcium sulfate doped with cerium and terbium, CaSO4:Ce,Tb (CSO). We present their synthesis, powder X-ray diffractograms, TL emission spectra, dose response, and sensitivity to ionizing radiation (compared to commercial LiF:Mg,Ti TL material). Important characteristics for temperature sensing applications, such as fading and bleaching, are presented and discussed. LBO and MBO presented in this work have TL emissions in separate regions of the spectrum, meaning that they can be used simultaneously for temperature measurements, their TL signal being separated in the laboratory using appropriate optical filters. The data presented in this paper provides the supporting basic information required to use these materials in temperature sensing experiments. -- Highlights: • Thermoluminescent (TL) materials were developed for temperature sensing. • Materials have TL intensity comparable or superior to commercial LiF:Mg,Ti. • TL from these materials saturate at higher dose than LiF:Mg,Ti. • TL materials shown minimum fading and light sensitivity. • Data provides basic information to support temperature sensing experiments

  3. BLENDED CALCIUM ALUMINATE-CALCIUM SULFATE CEMENT-BASED GROUT FOR P-REACTOR VESSEL IN-SITU DECOMMISSIONING

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C.; Stefanko, D.

    2011-03-10

    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH {<=} 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts [Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010]. Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere [Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively]. Radiolysis calculations are also provided in a separate document [Reyes-Jimenez, 2010].

  4. Blended Calcium Aluminate-Calcium Sulfate Cement-Based Grout For P-Reactor Vessel In-Situ Decommissioning

    International Nuclear Information System (INIS)

    The objective of this report is to document laboratory testing of blended calcium aluminate - calcium hemihydrate grouts for P-Reactor vessel in-situ decommissioning. Blended calcium aluminate - calcium hemihydrate cement-based grout was identified as candidate material for filling (physically stabilizing) the 105-P Reactor vessel (RV) because it is less alkaline than portland cement-based grout which has a pH greater than 12.4. In addition, blended calcium aluminate - calcium hemihydrate cement compositions can be formulated such that the primary cementitious phase is a stable crystalline material. A less alkaline material (pH ≤ 10.5) was desired to address a potential materials compatibility issue caused by corrosion of aluminum metal in highly alkaline environments such as that encountered in portland cement grouts (Wiersma, 2009a and b, Wiersma, 2010, and Serrato and Langton, 2010). Information concerning access points into the P-Reactor vessel and amount of aluminum metal in the vessel is provided elsewhere (Griffin, 2010, Stefanko, 2009 and Wiersma, 2009 and 2010, Bobbitt, 2010, respectively). Radiolysis calculations are also provided in a separate document (Reyes-Jimenez, 2010).

  5. Calcium Sulfate in Atacama Desert Basalt: A Possible Analog for Bright Material in Adirondack Basalt, Gusev Crater

    Science.gov (United States)

    Sutter, B.; Golden, D. C.; Amundson, R.; Chong-Diaz, G.; Ming, D. W.

    2007-01-01

    The Atacama Desert in northern Chile is one of the driest deserts on Earth (calcium sulfate (Ca-SO4) which was later confirmed by SEM/EDS analysis. This work examines the Ca-SO4 of Atacama basalt in an effort to provide insight into the possible nature of the bright material in the Adirondack basalt of Gusev Crater. The objectives of this work are to (i) discuss variations in Ca-SO4 crystal morphology in the vesicles and (ii) examine the Ca-SO4 interaction(s) with the basalt interior.

  6. The study of calcium sulfate decomposition by experiments under O{sub 2}/CO{sub 2} atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y. [HangZhou Dianzi Univ. (China). School of Science; Zhou, H.; Cen, K.F. [State Key Laboratory of Clean Energy Utilization, HangZhou (China); Liu, Y.H.; Stanger, R.; Elliot, L.; Wall, T. [Newcastle Univ. (Australia). Chemical Engineering

    2013-07-01

    Sulphur emission and the effect on ash properties and boiler- tube corrosion in oxy-fuel combustion have received increasing attention in the recent years. Early investigation about calcium- based desulphurization in oxy-fuel, addressed the advantage to reduce the SO{sub 2} emission. This paper, the decomposition of calcium sulphate was characterized by thermogravimetric analyzer. The results showed that the decomposition inhibited by increasing O{sub 2} concentration and SO{sub 2} concentration resulted from recycled flue gas. And CO{sub 2} concentration had the negative effect, which can be solved by changing O{sub 2} concentration through appropriately adjusting recycled flue gas ratio. The kinetics mechanism of calcium sulfate-decomposition in oxy-fuel combustion was further analyzed. Compared with conventional atmosphere, the reaction activation energy was heightened in oxy-fuel conditions, and the difference increased with rising temperature. So it can further confirm the advantage of calcium utilization rate under high temperature in oxy-fuel condition.

  7. Sulfurization of Fe-Ni-Cu-Co Alloy to Matte Phase by Carbothermic Reduction of Calcium Sulfate

    Science.gov (United States)

    Jeong, Eui Hyuk; Nam, Chul Woo; Park, Kyung Ho; Park, Joo Hyun

    2016-04-01

    Calcium sulfate (CaSO4) is proposed as an alternative sulfur source to convert the Fe-Ni-Cu-Co alloy to the matte phase. Solid carbon was used as a reducing agent and the influence of oxide fluxes on the sulfurization efficiency at 1673 K (1400 °C) in a CO-CO2-SO2-Ar atmosphere was investigated. When CaSO4 was equilibrated with the Fe-Ni-Cu-Co alloy without any reducing agent, it was reduced by Fe in the liquid alloy, resulting in the formation of FeS. The sulfurization efficiency was about 56 pct, even though an excess amount of CaSO4 (gypsum equivalent, G eq = 1.7) was added. Adding solid carbon as the reducing agent significantly shortened the equilibration time from 36 to 3.5 hours and increased the sulfurization efficiency from 56 to 91 pct, even though the amount of carbon was lower than the theoretical equivalent for carbothermic reduction of CaSO4, viz. C eq = 0.7. Although CaS (not FeS) was formed as a primary reaction product, it continuously reacted with CaSO4, forming CaO-rich slag. Neither the carbothermic reduction time nor the sulfurization efficiency were affected by the addition of Al2O3 (-SiO2) fluxes, but the equilibration time fell to 2.5 hours with the addition of Al2O3-Fe2O3 flux because the former systems produced primarily calcium silicate and calcium aluminate, which have relatively high melting points, whereas the latter system produced calcium ferrite, which has a lower melting point. Consequently, calcium sulfate (waste gypsum) can replace expensive pure sulfur as a raw material in the sulfurization of Fe-Ni-Cu-Co alloy with small amounts of iron oxide (Fe2O3) as a flux material. The present results can be used to improve the recovery of rare metals, such as Ni and Co, from deep sea manganese nodules.

  8. Acute intraoperative reactions during the injection of calcium sulfate bone cement for the treatment of unicameral bone cysts: a review of four cases.

    Science.gov (United States)

    Nystrom, Lukas; Raw, Robert; Buckwalter, Joseph; Morcuende, Jose A

    2008-01-01

    Unicameral bone cysts can predispose patients to pathologic fracture and deformities of growth. Treatment options vary from continuous decompression with transcortical placement of a cannulated screw to percutaneous aspiration and injection of medical-grade calcium sulfate. From 2005 to 2007, we treated 22 patients with unicameral bone cysts using aspiration and injection of calcium sulfate. Three patients experienced acute laryngospasm and one patient developed tachyarrhythmia, temporarily, associated with injection of calcium sulfate. All reactions occurred in patients under age 18 without predisposing risk factors and resolved spontaneously with supportive care. Although the mechanism is unclear, we hypothesize that these reactions are either due to the nociceptive stimulus of the calcium sulfate injection or a systemic calcium bolus. Clinicians using this product for this indication should be aware that such reactions may occur. We suggest endotracheal intubation and communication to the anesthesiologist about the time of the injection in preparation for these idiopathic responses. Further research is necessary to determine exactly how this reaction occurs and how it can be avoided. PMID:19223954

  9. Investigation of the formation of deposits of calcium sulfate on a metallic wall: detection and growth initiation

    International Nuclear Information System (INIS)

    Whereas the formation of calcium sulfate deposits on walls of (water desalination) heat exchanger tubes increases the load loss and decreases the heat exchange coefficient, measuring the load loss or measuring heat transfer in an exchanger could be a method to determine whether scaling occurs. In this research thesis, the author aims at a computational assessing of the sensitivity of such methods in conditions easily obtained in laboratory and allowing, if possible, the identification of the different steps of deposit formation. Then, the author considers some discontinuous methods, possibly more sensitive but more difficult to adjust, but which are not interesting in an industrial point of view: methods based on weighing, on chemical dosing, on radioactive measurements (tracers, auto-radiography, beta backscattering), optical methods and electric methods (piezoelectric quartz, conductivity measurements)

  10. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zonggang, E-mail: chenzg@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kang, Lingzhi [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Meng, Qing-Yuan [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Huanye [Department of Prosthodontics, School of Stomatology, China Medical University, Shenyang 110001 (China); Wang, Zhaoliang [Jinan Military General Hospital of PLA, Jinan 250031 (China); Guo, Zhongwu, E-mail: zwguo@sdu.edu.cn [National Glycoengineering Research Center, Shandong University, Jinan 250100 (China); Cui, Fu-Zhai, E-mail: cuifz@mail.tsinghua.edu.cn [Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-12-01

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials.

  11. Degradability of injectable calcium sulfate/mineralized collagen-based bone repair material and its effect on bone tissue regeneration

    International Nuclear Information System (INIS)

    The nHAC/CSH composite is an injectable bone repair material with controllable injectability and self-setting properties prepared by introducing calcium sulfate hemihydrate (CSH) into mineralized collagen (nHAC). When mixed with water, the nHAC/CSH composites can be transformed into mineralized collagen/calcium sulfate dihydrate (nHAC/CSD) composites. The nHAC/CSD composites have good biocompatibility and osteogenic capability. Considering that the degradation behavior of bone repair material is another important factor for its clinical applications, the degradability of nHAC/CSD composites was studied. The results showed that the degradation ratio of the nHAC/CSD composites with lower nHAC content increased with the L/S ratio increase of injectable materials, but the variety of L/S ratio had no significant effect on the degradation ratio of the nHAC/CSD composites with higher nHAC content. Increasing nHAC content in the composites could slow down the degradation of nHAC/CSD composite. Setting accelerator had no significant effect on the degradability of nHAC/CSD composites. In vivo histological analysis suggests that the degradation rate of materials can match the growth rate of new mandibular bone tissues in the implanted site of rabbit. The regulable degradability of materials resulting from the special prescriptions of injectable nHAC/CSH composites will further improve the workability of nHAC/CSD composites. - Highlights: • The nHAC/CSH composite can be as an injectable bone repair material. • The L/S ratio and nHAC content have a significant effect on material degradability. • The degradability of bone materials can be regulated to match tissue repair. • The regulable degradability will further improve the workability of bone materials

  12. Novel bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate: Fabrication, characterisation and evaluation of biocompatibility.

    Science.gov (United States)

    Chen, Yirong; Zhou, Yilin; Yang, Shenyu; Li, Jiao Jiao; Li, Xue; Ma, Yunfei; Hou, Yilong; Jiang, Nan; Xu, Changpeng; Zhang, Sheng; Zeng, Rong; Tu, Mei; Yu, Bin

    2016-09-01

    Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery. PMID:27207041

  13. Calcium carbonate and sulfate of possible extraterrestrial origin in the EETA 79001 meteorite

    Science.gov (United States)

    Gooding, James L.; Zolensky, Michael E.; Wentworth, Susan J.

    1988-01-01

    Two varieties of Ca-carbonate were found in a total of three interior (greater than 2-cm depth) samples of glass inclusions from the shergottite meteorite, Elephant Moraine, Antarctica, A79001. Two of the samples, including the largest deposit around a vug near the center of the meteorite (8-cm depth), contained veins of granular calcite with significant Mg and P, either as Mg-calcite with dissolved P or as calcite with very finely intergrown Mg-bearing phosphate. The second variety, which occurred in a third sample with a previously documented high concentration of trapped gases, consisted of disseminated 10-20-micron anhedral grains of nearly pure CaCO3 and was intimately associated with laths and needles of Ca-sulfate (possibly gypsum). All evidence considered, it is probable that both varieties of Ca-carbonate (and the Ca-sulfate) formed on a planetary body (probably Mars) before the meteorite fell on earth.

  14. Process for the reduction of the radioactivity of calcium sulfate from phosphorites

    International Nuclear Information System (INIS)

    The radioactivity of calcium sulphate prepared from phosphorites can be avoided by the addition of strong nitric or hydrochloric acid and ammonium salts, in particular ammonium nitrate or phosphate, either following or during acidic decomposition of the phosphorite. (orig./WI)

  15. Mechanical properties of high performance concrete made with high calcium high sulfate fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Sun, W. [Southeast Univ., Nanjing (China). Dept. of Materials Science and Engineering; Shang, L. [Nanjing Ningyuan Science and Technology Development Co., Nanjing (China)

    1997-07-01

    A high calcium fly ash with high SO{sub 3} content was used to produce high performance concrete. In all the mixes, the fly ash contents of 50% and 60% by weight were applied. Although fly ash cement pastes showed severe volume instability and poor pore structure development, mortars and concretes incorporating high mass high calcium fly ash exhibited good performance in both fresh and hardened state as those with low calcium fly ash did. The 3d and 28d compressive strength of mortars reached 25.2--42.2MPa respectively with the water binder ratio varying from 0.30 to 0.24. What is noticeable is that all the mortars and concretes showed good strength developing tendency with the 90d compressive strength up to 67.3--85.5MPa. This investigation reveals once more the fact that some materials which are not up to standard can still play a special role so long as the components are carefully chosen and proportions properly designed.

  16. Treatment of Infected Tibial Nonunion with Tobramycin- Impregnated Calcium Sulfate: Report of Two Cases.

    Directory of Open Access Journals (Sweden)

    Yao-Hung Tsai

    2004-07-01

    Full Text Available The treatment of infected tibial nonunion usually includes a staged reconstruction protocol.We present 2 patients with tibial nonunion and plate loosening with oxacillin-resistantStaphylococcus aureus infection. The patients were treated using the removal of the plate,radical debridement, and implantation of gentamycin-impregnated cement beads during thefirst stage. During the second stage, plate fixation was performed and tobramycin-impregnatedcalcium sulfate (Osteoset T® was used as a bone graft substitute. Neither an autogenousbone graft nor an allograft was used. At 3 years of follow-up, each tibia showed goodunion, and there was no recurrence of infection. We consider tobramycin-impregnated calciumsulfate to be an alternative method of bone grafting to treat infected tibial nonunion.

  17. Carbohydrate-Carbohydrate Interactions Mediated by Sulfate Esters and Calcium Provide the Cell Adhesion Required for the Emergence of Early Metazoans.

    Science.gov (United States)

    Vilanova, Eduardo; Santos, Gustavo R C; Aquino, Rafael S; Valle-Delgado, Juan J; Anselmetti, Dario; Fernàndez-Busquets, Xavier; Mourão, Paulo A S

    2016-04-29

    Early metazoans had to evolve the first cell adhesion mechanism addressed to maintain a distinctive multicellular morphology. As the oldest extant animals, sponges are good candidates for possessing remnants of the molecules responsible for this crucial evolutionary innovation. Cell adhesion in sponges is mediated by the calcium-dependent multivalent self-interactions of sulfated polysaccharides components of extracellular membrane-bound proteoglycans, namely aggregation factors. Here, we used atomic force microscopy to demonstrate that the aggregation factor of the sponge Desmapsamma anchorata has a circular supramolecular structure and that it thus belongs to the spongican family. Its sulfated polysaccharide units, which were characterized via nuclear magnetic resonance analysis, consist preponderantly of a central backbone composed of 3-α-Glc1 units partially sulfated at 2- and 4-positions and branches of Pyr(4,6)α-Gal1→3-α-Fuc2(SO3)1→3-α-Glc4(SO3)1→3-α-Glc→4-linked to the central α-Glc units. Single-molecule force measurements of self-binding forces of this sulfated polysaccharide and their chemically desulfated and carboxyl-reduced derivatives revealed that the sulfate epitopes and extracellular calcium are essential for providing the strength and stability necessary to sustain cell adhesion in sponges. We further discuss these findings within the framework of the role of molecular structures in the early evolution of metazoans. PMID:26917726

  18. Effects of neutral sulfate berberine on LPS-induced cardiomyocyte TNF-αsecretion, abnormal calcium cycling, and cardiac dysfunction in rats

    Institute of Scientific and Technical Information of China (English)

    Jing YANG; Hua-dong WANG; Da-xiang LU; Yan-ping WANG; Ren-bin QI; Jing LI; Fei LI; Chu-jie LI

    2006-01-01

    Aim: To evaluate the effect of neutral sulfate berberine on cardiac function, tumornecrosis factor α (TNF-α) release, and intracellular calcium concentration ([Ca2+]i)in cardiomyocytes exposed to lipopolysaccharide (LPS). Methods: Primary cultured rat cardiomyocytes were prepared from ventricles of 3-4-day old SpragueDawley rats. TNF-α concentrations in cell-conditioned media were measured by using a Quantikine enzyme-linked immunosorbent assay kit, and cardiomyocyte [Ca2+]i was measured by using Fura-2/AM. The isolated rat hearts were perfused in the Langendorff mode. Results: LPS at doses of 1, 5, 10, and 20 μg/mL markedly stimulated TNF-α secretion from cardiomyocytes, and neutral sulfate berberine inhibited LPS-induced TNF-α production. Intracellular calcium concentration was significantly decreased after LPS stimulation for 1 h, and increased 2 h after LPS treatment. Pretreatment with neutral sulfate berberine reversed the LPS-induced [Ca2+]i alterations, although neutral sulfate berberine did not inhibit a rapid increase in cardiomyocyte [Ca2+]i induced by LPS. Perfusion of isolated hearts with LPS (100 μg/mL) for 20 min resulted in significantly impaired cardiac performance at 120 min after LPS challenge: the maximal rate of left ventricular pressure rise and fall (±dp/dtmax) decreased compared with the control. In contrast, ±dp/dtmax at 120min in hearts perfused with neutral sulfate berberine (1 μmol/L) for 10 min followed by 20 min LPS (100 μg/mL) was greater than the corresponding value in the LPS group. Conclusion: Neutral sulfate berberine inhibits LPS-stimulated myocardial TNF-α production, impairs calcium cycling, and improves LPS-induced contractile dysfunction in intact heart.

  19. The influence of calcium, magnesium, phosphorus and silica in vanadium precipitation in acidic sulfate solutions

    International Nuclear Information System (INIS)

    The experimental research work was carried out in accordance with the Factorial Design Statistical Method to evaluate and analyze the influence of calcium, magnesium, silica and phosphorus on the precipitation of vanadates. precipitation was performed by neutralization with H2 SO4 of alkaline aqueous solutions containing vanadium pentoxide (V2 O5) at 60 ± 2 deg C. The experimental responses measured were percent of vanadium recovery and vanadium pentoxide content in the precipitate. These impurities are considered representative of those present in a leach liquor from the ore obtained at Campo Alegre de Lourdes (Brazil). The operational variables in this work were used optimum conditions as determined by the statistical approach. Among the impurities under study, phosphorus exhibited the highest negative influence on the experimental responses. Phosphorus diminished the percent of vanadium recovered from 98.9 to 34.5 and the vanadium oxide content in the precipitate from 91.2% to 39.3%. (author)

  20. Effect of Compounding of Sodium Tripolyphosphate and Super Plasticizers on the Hydration of α-calcium Sulfate Hemihydrate

    Institute of Scientific and Technical Information of China (English)

    PAN Wei; WANG Peiming

    2011-01-01

    The inhibition and its mechanism of sodium tripolyphosphate(STP)composited with super plasticizers(SPs)on hydration of α-calcium sulfate hemihydrate were studied by setting time,strength,hydration heat,X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),electronic probe micro analysis (EPMA),scanning electron microscopy(SEM)and differential scanning calorimeter(DSC)measurements.The experimental results show that compared with STP addition,compositing STP with polycarboxylate(PC)plasticizer,the final setting time is prolonged from 0.5h to 2hs.While formulating STP with naphthalene-based plasticizer(NAP)or sulfonate melamine formaldehyde plasticizer(SMF),the final setting time is reduced to quarter of an hour Similar changes can also be found in the rate of exothermic hydration and hydration degree.Formulating STP with suitable addition of PC can enhance the strength,while compositing STP and NAP or SMF weakens the strength.Besides,adding STP or STP and SMF,obvious movement(more than lev)of binding energy of Ca2p1/2 and Ca2p3/2 is detected.Compared with STP addition,content of the characteristic element(P)of STP is cut down form 1.1% to 0.49% by compositing STP with SMF.Furthermore,as hydration age increases,hydration inhibition in the presence of admixtures weakens and even disappears within 56 h.

  1. Characterization and precipitation mechanism of α-calcium sulfate hemihydrate growing out of FGD gypsum in salt solution

    Institute of Scientific and Technical Information of China (English)

    YANG LiuChun; GUAN BaoHong; WU ZhongBiao

    2009-01-01

    Alpha-calcium sulfate hemihydrate (α-HH) has been prepared from flue gas desulfurization (FGD)gypsum with salt solution method under atmospheric pressure. X-ray diffraction (XRD), thermogra-vimetry and differential scanning calorimetry (TG-DSC), optical micrograph, X-ray photoelectron spec-troscopy (XPS), energy dispersive spectrometry (EDS), and scanning electron microscopy (SEM) have been employed to characterize the α-HH crystals, based on which the formation and growth mecha-nisms of the a-HH crystals have been discussed. The results show that FGD gypsum can be success-fully transformed into high purity α-HH in salt solution under mild conditions, and that a dissolu-tion-recrystallization route is most probably adopted by this transition. The growth of a-HH crystals in salt solution demonstrates a preferred direction along [001] and results in a bundle-of-sheets or bun-dle-of-raphide texture. The characteristics revealed in this study can help to understand and control the growth of the α-HH crystal from solution.

  2. Calcium sulfate spinal cord scaffold: a study on degradation and fibroblast growth factor 1 loading and release.

    Science.gov (United States)

    Åberg, Jonas; Eriksson, Olof; Spens, Erika; Nordblom, Jonathan; Mattsson, Per; Sjödahl, Johan; Svensson, Mikael; Engqvist, Håkan

    2012-02-01

    Currently, there is no regenerative strategy for the spinal cord that is part of clinical standard of core. Current paths usually include combinations of scaffold materials and active molecules. In a recent study, a permanent dental resin scaffold for treatment of spinal cord injury was designed. The results from studies on rats were promising. However, for potential clinical use, a biodegradable scaffold material that facilitates drug delivery and the regeneration of the spinal cord needs to be developed. Also a biodegradable material is expected to allow a better evaluation of the efficacy of the surgical method. In this article, the suitability of hardened calcium sulfate cement (CSC) for use as degradable spinal cord scaffolds is investigated in bench studies and in vitro studies. Compressive strength, degradation and microstructure, and the loading capability of heparin-activated fibroblast growth factor 1 (FGF1) via soaking were evaluated. The CSC could easily be injected into the scaffold mold and the obtained scaffolds had sufficient strength to endure the loads applied during surgery. When hardened, the CSC formed a porous microstructure suitable for loading of active substances. It was shown that 10 min of FGF1 soaking was enough to obtain a sustained active FGF1 release for 20-35 days. The results showed that CSC is a promising material for spinal cord scaffold fabrication, since it is biodegradable, has sufficient strength, and allows loading and controlled release of active FGF1. PMID:20624845

  3. The influence of calcium, magnesium, phosphorus and silica on vanadium precipitation in acidic sulfate solutions

    Directory of Open Access Journals (Sweden)

    Martins A. H.

    2000-01-01

    Full Text Available The experimental research work was carried out in accordance with the Factorial Design Statistical Method to evaluate and analyze the influence of calcium, magnesium, silica and phosphorus on the precipitation of vanadates. Precipitation was performed by neutralization with H2SO4 of alkaline aqueous solutions containing vanadium pentoxide (V2O5 at 60± 2ºC. The experimental responses measured were percent of vanadium recovery and vanadium pentoxide content in the precipitate. These impurities are considered representative of those present in a leach liquor from the ore obtained at Campo Alegre de Lourdes (Brazil. The operational variables in this work were used under optimum conditions as determined by the statistical approach. Among the impurities under study, phosphorus exhibited the highest negative influence on the experimental responses. Phosphorus diminished the percent of vanadium recovered from 98.9 to 34.5 and the vanadium oxide content in the precipitate from 91.2 % to 39.3 %.

  4. Evaluation of colloidal silica suspension as efficient additive for improving physicochemical and in vitro biological properties of calcium sulfate-based nanocomposite bone cement.

    Science.gov (United States)

    Borhan, Shokoufeh; Hesaraki, Saeed; Ahmadzadeh-Asl, Shaghayegh

    2010-12-01

    In the present study new calcium sulfate-based nanocomposite bone cement with improved physicochemical and biological properties was developed. The powder component of the cement consists of 60 wt% α-calcium sulfate hemihydrate and 40 wt% biomimetically synthesized apatite, while the liquid component consists of an aqueous colloidal silica suspension (20 wt%). In this study, the above mentioned powder phase was mixed with distilled water to prepare a calcium sulfate/nanoapatite composite without any additive. Structural properties, setting time, compressive strength, in vitro bioactivity and cellular properties of the cements were investigated by appropriate techniques. From X-ray diffractometer analysis, except gypsum and apatite, no further phases were found in both silica-containing and silica-free cements. The results showed that both setting time and compressive strength of the calcium sulfate/nanoapatite cement improved by using colloidal silica suspension as cement liquid. Meanwhile, the condensed phase produced from the polymerization process of colloidal silica filled the micropores of the microstructure and covered rodlike gypsum crystals and thus controlled cement disintegration in simulated body fluid. Additionally, formation of apatite layer was favored on the surfaces of the new cement while no apatite precipitation was observed for the cement prepared by distilled water. In this study, it was also revealed that the number of viable osteosarcoma cells cultured with extracts of both cements were comparable, while silica-containing cement increased alkaline phosphatase activity of the cells. These results suggest that the developed cement may be a suitable bone filling material after well passing of the corresponding in vivo tests. PMID:20972610

  5. A thermodynamic investigation of barium and calcium sulfate stability in sediments at an oceanic ridge axis (Juan de Fuca, ODP legs 139 and 169)

    OpenAIRE

    Monnin, Christophe; Balleur, Sabine; Goffé, Bruno

    2003-01-01

    We have used a new thermodynamic model of barium and calcium sulfate solubilities in multicomponent electrolyte solutions (Monnin, 1999) to investigate the stabilities of barite and anhydrite in seawater or in marine sediment porewaters at high temperature and pressure. As a further test supplementing those previously carried out during model development, we have calculated the temperature at which standard seawater becomes saturated with respect to anhydrite. The model predicts that, upon he...

  6. THERMOANALYTICAL EVENTS AND ENTHALPIES OF SELECTED PHASES AND SYSTEMS OF THE CHEMISTRY AND TECHNOLOGY OF CONCRETE PART I. CALCIUM-SILICATE-ALUMINATE-SULFATE HYDRATES

    OpenAIRE

    Milan Drabik; Lubica Galikova; Scholtzova Eva; Hadzimova Eva

    2014-01-01

    Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - (delta)H, of natural minerals of calcium-silicate-sulfate-aluminate hydrates. The thermoanalytical curves of thaumasite and ettringite are fully in line with that reported in reference sources. The values of (delta)H calculated from DSC curves in the intervals of key decomposition steps ranging from 50 to 250 C, achieve (1215 +/- 60) J g-1 for thaumasite and (930 +/- 40) J g...

  7. Bone healing response to a synthetic calcium sulfate/β-tricalcium phosphate graft material in a sheep vertebral body defect model

    OpenAIRE

    Yang, H. L.; Zhu, X S; Chen, L.; Chen, C. M.; Mangham, D C; Coulton, L A; Aiken, S. S.

    2012-01-01

    Abstract The introduction of a material able to promote osteogenesis and remodelling activity in a clinically relevant time frame in vertebroplasty and kyphoplasty procedures may have patient benefit. We report the in-vivo performance of a biphasic synthetic bone graft material (Genex Paste, Biocomposites, UK) [test material], composed of calcium sulfate and β-tricalcium phosphate, implanted into a sheep vertebral defect model. Cavities drilled into 4 adjacent vertebrae (L2 to L5) of 24 skele...

  8. Thermal simulation experiments of saturated hydro-carbons with calcium sulfate and element sulfur: Implications on origin of H_2S

    Institute of Scientific and Technical Information of China (English)

    CHEN TengShui; HE Qin; LU Hong; PENG PingAn; LIU JinZhong

    2009-01-01

    Temperature-programmed simulation experiments of saturated hydrocarbons with calcium sulfate and element sulfur were compared in this study. Based on the variation analysis of the yields and evolve-ment features of gaseous hydrocarbon (C_1-C_5) and inorganic gaseous CO_2, H_2 and H_2S, the reaction mechanisms were analyzed and discussed. In the calcium sulfate-saturated hydrocarbon system, H2S was produced by a small quantity, which indicates this reaction belongs to the low-degreed thermal sulfate reduction (TSR) and is featured of self-pyrolysis. In the sulfur-saturated hydrocarbon system, the heated sulfur becomes sulfur radical, which has strong catalysis capability and can fasten the cracking of C-H bond in the alkyl group in the saturated hydrocarbons. As a result, the cracking of C-H bond leads to the yields enhancement of CO_2 and H_2, and at the same time, H2S was produced since the cracked hydrogen can be instantly combined with sulfur radical. Therefore, this reaction in the sulfur-hydrocarbon system belongs to the catalysis of sulfur radical. Furthermore, the promoted pyro-lysis effects of C_(6+). hydrocarbons by sulfur radical in the low-temperature stage in the sul-fur-hydrocarbon system, together with the consumption effects of gaseous hydrocarbon in the high-temperature stage in the calcium-hydrocarbon system, result in the crossed phenomenon of the gaseous hydrocarbon yields curves.

  9. Adsorption and substitution effects of Mg on the growth of calcium sulfate hemihydrate: An ab initio DFT study

    Science.gov (United States)

    Xin, Yan; Hou, S. C.; Xiang, Lan; Yu, Yang-Xin

    2015-12-01

    Calcium sulfate hemihydrate (CaSO4·0.5H2O, CSH) whiskers with high aspect ratio are promising reinforce materials which have drawn much attention. In order to obtain high quality CSH materials, effect of Mg2+ ions on properties of the (0 0 2), (2 0 0)1 and (2 0 0)2 planes of CSH is investigated using an ab initio density functional theory (DFT) with a van der Waals (vdW) dispersion-correction. The computed results show that strong adsorption and substitution effects take place between Mg2+ ion and (2 0 0)1 plane. The adsorption energies of an Mg2+ ion on the (0 0 2), (2 0 0)1 and (2 0 0)2 planes are -0.066, -0.571 and -0.047 eV, respectively. An insight into the electrostatic potential of pristine CSH planes has demonstrated that the (2 0 0)1 plane is much more negatively charged than the (0 0 2) and (2 0 0)2 planes. The energies of the substitution of a Ca atom with an Mg atom on the CSH (0 0 2), (2 0 0)1 and (2 0 0)2 planes are 1.572, 0.063 and 1.349 eV, respectively. It is found that Ca atoms on the (2 0 0)1 plane are relatively easy to be substituted by Mg atoms. The calculation results of a Ca2+ ion adsorption on the Mg-doped (2 0 0)1 plane indicate that the adsorption energies increase apparently as the doping ratio varies from 0 to 1.0. Compared with K+, Na+ and Al3+ ions, Mg2+ ion is the most promising additive to promote the growth of CSH along c axis.

  10. Hydroxyapatite-calcium sulfate-hyaluronic acid composite encapsulated with collagenase as bone substitute for alveolar bone regeneration.

    Science.gov (United States)

    Subramaniam, Sadhasivam; Fang, Yen-Hsin; Sivasubramanian, Savitha; Lin, Feng-Huei; Lin, Chun-pin

    2016-01-01

    Periodontitis is a very severe inflammatory condition of the periodontium that progressively damages the soft tissue and destroys the alveolar bone that supports the teeth. The bone loss is naturally irreversible because of limited reparability of the teeth. Advancement in tissue engineering provides an effective regeneration of osseous defects with suitable dental implants or tissue-engineered constructs. This study reports a hydroxyapatite, calcium sulfate hemihydrate and hyaluronic acid laden collagenase (HAP/CS/HA-Col) as a bone substitute for the alveolar bone regeneration. The composite material was mechanically tested and the biocompatibility was evaluated by WST-1 assay. The in vivo bone formation was assessed in rat with alveolar bone defects and the bone augmentation by the HAP/CS/HA-Col composite was confirmed by micro-CT images and histological examination. The mechanical strength of 6.69 MPa with excellent biocompatibility was obtained for the HAP/CS/HA-Col composite. The collagenase release profile had facilitated the acceleration of bone remodeling process and it was confirmed by the findings of micro-CT and H&E staining. The bone defects implanted with HAP/CS/HA composite containing 2 mg/mL type I collagenase have shown improved new bone formation with matured bone morphology in comparison with the HAP/CS/HA composite that lacks the collagenase and the porous hydroxyapatite (p-HAP) granules. The said findings demonstrated that the collagenase inclusion in HAP/CS/HA composite is a feasible approach for the alveolar bone regeneration and the same design can also be applied to other defective tissues. PMID:26454048

  11. Enhanced healing of rat calvarial defects with sulfated chitosan-coated calcium-deficient hydroxyapatite/bone morphogenetic protein 2 scaffolds.

    Science.gov (United States)

    Zhao, Jun; Shen, Gang; Liu, Changsheng; Wang, Shaoyi; Zhang, Wenjie; Zhang, Xiaochen; Zhang, Xiuli; Ye, Dongxia; Wei, Jie; Zhang, Zhiyuan; Jiang, Xinquan

    2012-01-01

    Calcium phosphate cements (CPCs), which are widely used in bone regeneration, possess good biocompatibility and osteoconductivity and have been demonstrated to be candidate carriers for bone growth factors. However, limited release of growth factors from CPCs and slow degradation of the materials are not desirable for certain clinical applications. Previous studies have shown that calcium-deficient hydroxyapatite (CDHA) from CPCs presents more rapid degradation rate than CPCs. In this study, a hybrid growth factor delivery system was prepared by using bone morphogenetic protein 2 (BMP-2) loaded CDHA porous scaffold with sulfated chitosan (SCS) coating for improved release profile. We tested the BMP-2 release characteristic of CDHA/BMP-2/SCS composite in vitro and its ability to repair rat calvarial bone defects. A higher percentage of BMP-2 was released when sulfated chitosan coating was present compared with CDHA/BMP-2 group. Eight weeks postoperation, the repaired crania were evaluated by microcomputed tomography, sequential fluorescent labeling, histological analysis, and immunohistochemistry. CDHA/BMP-2/SCS group promoted the most extensive new bone formation than CDHA/BMP-2 and CDHA groups. Our observations suggest that sulfated chitosan coating could enhance the release profile of CDHA/BMP-2 composite in vitro and promote new bone formation in vivo. The hybrid CDHA/BMP-2/SCS system is a promising growth factor delivery strategy for bone regeneration. PMID:21830854

  12. A novel resorbable strontium-containing α-calcium sulfate hemihydrate bone substitute: a preparation and preliminary study

    International Nuclear Information System (INIS)

    Distraction osteogenesis after aggrieved bone segment resections is promising in the treatment of bone tumors and osteomyelitis. However, there is ambiguity with regard to the optimal choice of bone substitute, with biodegradability and excellent bone repair performance constituting key requirements. The purpose of this study was to develop a novel resorbable strontium-containing α-calcium sulfate hemihydrate (Sr-CaS) bone substitute to provide an alternative option for surgeons that better meets these requirements. The Sr-CaS was prepared using co-precipitation and hydrothermal methods and analyzed using x-ray diffraction (XRD), Fourier transform infrared (FTIR) scanning and thermogravimetric differential scanning calorimeter (TG–DSC) patterns. Cytotoxicity by tetrazolium bromide (MTT), sub-acute toxicity and hemolysis tests were performed to assess the initial biocompatibility of the new bone substitute. Radiographic analysis, micro-CT measurements and histological observation were used to evaluate the bone repair ability in rat tibia bone defects. The XRD and FTIR patterns of Sr-CaS were both very similar to CaS and the product had comparable characteristics similar to α-CaS as demonstrated by TG-DSC. Cytotoxicity of the substitute was class 1 (no cytotoxicity) and hemolysis was 4.3% (no hemolysis). Sub-acute toxicity was not seen after a 14 day evaluation. The substitute was radio-opaque. The empty group exhibited the lowest levels of both bone mineral densities (BMD) and bone volume/total volume (BV/TV) of the defects when compared to all other groups. The two Sr-CaS groups resulted in significantly greater BMDs and BV/TV of the defect compared to the CaS only group. However, there was no significant difference between the 5% and 10% Sr-CaS groups. The Sr-CaS was resorbable with satisfactory biocompatibility. The doped strontium ions enhanced the bone repair performance of CaS in a rat model and the new substitute demonstrated promising results for

  13. A novel resorbable strontium-containing α-calcium sulfate hemihydrate bone substitute: a preparation and preliminary study.

    Science.gov (United States)

    Li, Xue; Xu, Chang-peng; Hou, Yi-long; Song, Jin-qi; Cui, Zhuang; Wang, Sheng-nan; Huang, Lei; Zhou, Chang-ren; Yu, Bin

    2014-08-01

    Distraction osteogenesis after aggrieved bone segment resections is promising in the treatment of bone tumors and osteomyelitis. However, there is ambiguity with regard to the optimal choice of bone substitute, with biodegradability and excellent bone repair performance constituting key requirements. The purpose of this study was to develop a novel resorbable strontium-containing α-calcium sulfate hemihydrate (Sr-CaS) bone substitute to provide an alternative option for surgeons that better meets these requirements. The Sr-CaS was prepared using co-precipitation and hydrothermal methods and analyzed using x-ray diffraction (XRD), Fourier transform infrared (FTIR) scanning and thermogravimetric differential scanning calorimeter (TG-DSC) patterns. Cytotoxicity by tetrazolium bromide (MTT), sub-acute toxicity and hemolysis tests were performed to assess the initial biocompatibility of the new bone substitute. Radiographic analysis, micro-CT measurements and histological observation were used to evaluate the bone repair ability in rat tibia bone defects. The XRD and FTIR patterns of Sr-CaS were both very similar to CaS and the product had comparable characteristics similar to α-CaS as demonstrated by TG-DSC. Cytotoxicity of the substitute was class 1 (no cytotoxicity) and hemolysis was 4.3% (no hemolysis). Sub-acute toxicity was not seen after a 14 day evaluation. The substitute was radio-opaque. The empty group exhibited the lowest levels of both bone mineral densities (BMD) and bone volume/total volume (BV/TV) of the defects when compared to all other groups. The two Sr-CaS groups resulted in significantly greater BMDs and BV/TV of the defect compared to the CaS only group. However, there was no significant difference between the 5% and 10% Sr-CaS groups. The Sr-CaS was resorbable with satisfactory biocompatibility. The doped strontium ions enhanced the bone repair performance of CaS in a rat model and the new substitute demonstrated promising results for clinical

  14. 硫酸钙晶须的制备及其在塑料中的应用%Preparation of Calcium Sulfate Whisker and It's Application in Plastics

    Institute of Scientific and Technical Information of China (English)

    田浩; 薛涛; 聂登攀; 王振杰

    2012-01-01

    评述硫酸钙晶须的基本性能、制备及其在塑料中应用.提出利用磷石膏制备硫酸钙晶须有望成为解决磷石膏污染的新途径,同时可对天然石膏资源的滥采现象起到防治作用.%The basic properties, preparation and application in plastics of calcium sulfate whiskers are reviewed. Preparation of calcium phosphate whisker using Phosphogypsum is expected to become a new way to solve Phosphogypsum pollution , and prevent and cure an abuse phenomenon of the natural gypsum resources.

  15. Reactions Involving Calcium and Magnesium Sulfates as Potential Sources of Sulfur Dioxide During MSL SAM Evolved Gas Analyses

    Science.gov (United States)

    McAdam, A. C.; Knudson, C. A.; Sutter, B.; Franz, H. B.; Archer, P. D., Jr.; Eigenbrode, J. L.; Ming, D. W.; Morris, R. V.; Hurowitz, J. A.; Mahaffy, P. R.; Navarro-Gonzalez, R.

    2016-01-01

    The Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) instruments on the Mars Science Laboratory (MSL) have analyzed several subsamples of 860 C). Sulfides or Fe sulfates were detected by CheMin (e.g., CB, MJ, BK) and could contribute to the high temperature SO2 evolution, but in most cases they are not present in enough abundance to account for all of the SO2. This additional SO2 could be largely associated with x-ray amorphous material, which comprises a significant portion of all samples. It can also be attributed to trace S phases present below the CheMin detection limit, or to reactions which lower the temperatures of SO2 evolution from sulfates that are typically expected to thermally decompose at temperatures outside the SAM temperature range (e.g., Ca and Mg sulfates). Here we discuss the results of SAM-like laboratory analyses targeted at understanding this last possibility, focused on understanding if reactions of HCl or an HCl evolving phase (oxychlorine phases, chlorides, etc.) and Ca and Mg sulfates can result in SO2 evolution in the SAM temperature range.

  16. Sulfate and thiosulfate inhibit oxalate transport via a dPrestin (Slc26a6)-dependent mechanism in an insect model of calcium oxalate nephrolithiasis.

    Science.gov (United States)

    Landry, Greg M; Hirata, Taku; Anderson, Jacob B; Cabrero, Pablo; Gallo, Christopher J R; Dow, Julian A T; Romero, Michael F

    2016-01-15

    Nephrolithiasis is one of the most common urinary tract disorders, with the majority of kidney stones composed of calcium oxalate (CaOx). Given its prevalence (US occurrence 10%), it is still poorly understood, lacking progress in identifying new therapies because of its complex etiology. Drosophila melanogaster (fruitfly) is a recently developed model of CaOx nephrolithiasis. Effects of sulfate and thiosulfate on crystal formation were investigated using the Drosophila model, as well as electrophysiological effects on both Drosophila (Slc26a5/6; dPrestin) and mouse (mSlc26a6) oxalate transporters utilizing the Xenopus laevis oocyte heterologous expression system. Results indicate that both transport thiosulfate with a much higher affinity than sulfate Additionally, both compounds were effective at decreasing CaOx crystallization when added to the diet. However, these results were not observed when compounds were applied to Malpighian tubules ex vivo. Neither compound affected CaOx crystallization in dPrestin knockdown animals, indicating a role for principal cell-specific dPrestin in luminal oxalate transport. Furthermore, thiosulfate has a higher affinity for dPrestin and mSlc26a6 compared with oxalate These data indicate that thiosulfate's ability to act as a competitive inhibitor of oxalate via dPrestin, can explain the decrease in CaOx crystallization seen in the presence of thiosulfate, but not sulfate. Overall, our findings predict that thiosulfate or oxalate-mimics may be effective as therapeutic competitive inhibitors of CaOx crystallization. PMID:26538444

  17. Cytotoxic Effects and Osteogenic Activity of Calcium Sulfate with and without Recombinant Human Bone Morphogenetic Protein 2 and Nano-Hydroxyapatite Adjacent to MG-63 Cell Line

    Directory of Open Access Journals (Sweden)

    Abdollah Ghorbanzadeh

    2015-10-01

    Full Text Available Objectives: The aim of this study was to assess the cytotoxic effects and osteogenic activity of recombinant human bone morphogenetic protein (rhBMP2 and nano-hydroxyapatite (n- HA adjacent to MG-63 cell line.Materials and Methods: To assess cytotoxicity, the 4,5-dimethyl thiazolyl-2,5-diphenyl tetrazolium bromide (MTT assay was used. Alkaline phosphatase (ALP activity and oste- ogenic activity were evaluated using Alizarin red and the von Kossa staining and analyzed by one-way ANOVA followed by Tukey’s post hoc test.Results: The n-HA/CS mixture significantly promoted cell growth in comparison to pure calcium sulfate (CS. Moreover, addition of rhBMP2 to CS (P=0.02 and also mixing CS with n-HA led to further increase in extracellular calcium production and ALP activity (P=0.03.Conclusion: This in vitro study indicates that a scaffold material in combination with an osteoinductive material is effective for bone matrix formation.

  18. Combination of calcium sulfate and simvastatin-controlled release microspheres enhances bone repair in critical-sized rat calvarial bone defects

    Directory of Open Access Journals (Sweden)

    Fu YC

    2015-12-01

    Full Text Available Yin-Chih Fu,1–4 Yan-Hsiung Wang,1,5 Chung-Hwan Chen,1,3,4 Chih-Kuang Wang,1,6 Gwo-Jaw Wang,1,3,4 Mei-Ling Ho1,3,7,8 1Orthopaedic Research Center, 2Graduate Institute of Medicine, 3Department of Orthopaedics, 4Department of Orthopaedics, College of Medicine, 5School of Dentistry, College of Dental Medicine, 6Department of Medicinal and Applied Chemistry, 7Department of Physiology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; 8Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, TaiwanAbstract: Most allogenic bone graft substitutes have only osteoconductive properties. Developing new strategies to improve the osteoinductive activity of bone graft substitutes is both critical and practical for clinical application. Previously, we developed novel simvastatin-encapsulating poly(lactic-co-glycolic acid microspheres (SIM/PLGA that slowly release simvastatin and enhance fracture healing. In this study, we combined SIM/PLGA with a rapidly absorbable calcium sulfate (CS bone substitute and studied the effect on bone healing in critical-sized calvarial bone defects in a rat model. The cytotoxicity and cytocompatibility of this combination was tested in vitro using lactate dehydrogenase leakage and a cell attachment assay, respectively. Combination treatment with SIM/PLGA and the CS bone substitute had no cytotoxic effect on bone marrow stem cells. Compared with the control, cell adhesion was substantially enhanced following combination treatment with SIM/PLGA and the CS bone substitute. In vivo, implantation of the combination bone substitute promoted healing of critical-sized calvarial bone defects in rats; furthermore, production of bone morphogenetic protein-2 and neovascularization were enhanced in the area of the defect. In summary, the combination of SIM/PLGA and a CS bone substitute has osteoconductive and osteoinductive properties, indicating that it could be used for regeneration

  19. Biocompatibility evaluation of dicalcium phosphate/calcium sulfate/poly (amino acid) composite for orthopedic tissue engineering in vitro and in vivo.

    Science.gov (United States)

    Wang, Peng; Liu, Pengzheng; Peng, Haitao; Luo, Xiaoman; Yuan, Huipin; Zhang, Juncai; Yan, Yonggang

    2016-08-01

    In vitro cytocompatibility of ternary biocomposite of dicalcium phosphate (DCP) and calcium sulfate (CS) containing 40 wt% poly (amino acid) (PAA) was evaluated using L929 fibroblasts and MG-63 osteoblast-like cells. Thereafter, the biocompatibility of biocomposite in vivo was investigated using an implantation in muscle and bone model. In vitro L929 and MG-63 cell culture experiments showed that the composite and PAA polymer were noncytotoxic and allowed cells to adhere and proliferate. The scanning electron microscope (SEM) confirmed that two kinds of cells maintained their phenotype on all of samples surfaces. Moreover, the DCP/CS/PAA composite showed higher cellular viability than that of PAA; meanwhile, the cell proliferation and ALP activity were much higher when DCP/CS had added into PAA. After implanted in muscle of rabbits for 12 weeks, the histological evaluation indicated that the composite exhibited excellent biocompatibility and no inflammatory responses were found. When implanted into bone defects of femoral condyle of rabbits, the composite was combined directly with the host bone tissue without fibrous capsule tissue, which shown good biocompatibility and osteoconductivity. Thus, this novel composite may have potential application in the clinical setting. PMID:27126299

  20. An In Vitro Comparison of PMMA and Calcium Sulfate as Carriers for the Local Delivery of Gallium(III) Nitrate to Staphylococcal Infected Surgical Sites.

    Science.gov (United States)

    Garcia, Rebecca A; Tennent, David J; Chang, David; Wenke, Joseph C; Sanchez, Carlos J

    2016-01-01

    Antibiotic-loaded bone cements, including poly(methyl methacrylate) (PMMA) and calcium sulfate (CaSO4), are often used for treatment of orthopaedic infections involving Staphylococcus spp., although the effectiveness of this treatment modality may be limited due to the emergence of antimicrobial resistance and/or the development of biofilms within surgical sites. Gallium(III) is an iron analog capable of inhibiting essential iron-dependent pathways, exerting broad antimicrobial activity against multiple microorganisms, including Staphylococcus spp. Herein, we evaluated PMMA and CaSO4 as carriers for delivery of gallium(III) nitrate (Ga(NO3)3) to infected surgical sites by assessing the release kinetics subsequent to incorporation and antimicrobial activity against S. aureus and S. epidermidis. PMMA and to a lesser extent CaSO4 were observed to be compatible as carriers for Ga(NO3)3, eluting concentrations with antimicrobial activity against planktonic bacteria, inhibiting bacterial growth, and preventing bacterial colonization of beads, and effective against established bacterial biofilms of S. aureus and S. epidermidis. Collectively, our in vitro results indicate that PMMA is a more suitable carrier compared to CaSO4 for delivery of Ga(NO3)3; moreover they provide evidence for the potential use of Ga(NO3)3 with PMMA as a strategy for the prevention and/or treatment for orthopaedic infections. PMID:26885514

  1. Application of Anhydrous Calcium Sulfate as a Partial Replacement for Titanium Dioxide%无水硫酸钙部分替代钛白粉的应用

    Institute of Scientific and Technical Information of China (English)

    黄明杰; 邵聂

    2013-01-01

    The present price of titanium dioxide is high, but research of titanium composite pigment in domestic is still in the initial stage. Titanium dioxide has many advantages, but people have to consider other products replacing titanium dioxide due to its expensive price. In order to save the expensive titanium dioxide and reduce costs, people have been actively researched and developed and used efficient and inexpensive extender pigments instead of titanium dioxide for a long time. It is imperative to research new product replacing titanium dioxide partly. Because calcium sulfate has good whiteness and gelling property, it can partly replace titanium dioxide in the coating, maximum substitution is 20%of titanium dioxide.%  目前钛白粉的价格居高不下,而且在国内钛复合颜料的研究尚处于起步阶段。钛白粉具有很多优势,但是其昂贵的价格让人们不得不考虑采用其他的产品来替代钛白粉。为了节省昂贵的钛白粉,降低成本,长期以来人们都积极地研究和开发利用高效价廉的体质颜料取代钛白粉,研究新的产品部分替代钛白粉势在必行。由于硫酸钙具有良好的白度以及胶凝性,故可部分替代钛白粉添加到涂料中,最大替代量为钛白粉用量的20%。

  2. Radiation damage in calcium sulfate

    International Nuclear Information System (INIS)

    We used the techniques of Electron Paramagnetic Resonance (EPR) to study the free radicals produced by X-radiation in natural crystals of Gypsum (CaSO42H20). We observed the formation of four free radicals. The spectra of these radicals are overlapped, being separated by power and temperature variation measurements. Two radicals were univocal identified, as being of OH+ and 02H+. We suggest the assignment of SO4- and O2- to two other radicals. From angular variation measurements, we determined the components of tensors ↔g and ↔A of the radicals OH- and O2H-. (author)

  3. Integration of a Novel Injectable Nano Calcium Sulfate/Alginate Scaffold and BMP2 Gene-Modified Mesenchymal Stem Cells for Bone Regeneration

    Science.gov (United States)

    He, Xiaoning; Dziak, Rosemary; Mao, Keya; Genco, Robert; Swithart, Mark; Li, Chunyi

    2013-01-01

    The repair of craniofacial bone defects is surgically challenging due to the complex anatomical structure of the craniofacial skeleton. Current strategies for bone tissue engineering using a preformed scaffold have not resulted in the expected clinical regeneration due to difficulty in seeding cells into the deep internal space of scaffold, and the inability to inject them in minimally invasive surgeries. In this study, we used the osteoconductive and mechanical properties of nano-scale calcium sulfate (nCS) and the biocompatibility of alginate to develop the injectable nCS/alginate (nCS/A) paste, and characterized the effect of this nCS/A paste loaded with bone morphogenetic protein 2 (BMP2) gene-modified rat mesenchymal stem cells (MSCs) on bone and blood vessel growth. Our results showed that the nCS/A paste was injectable under small injection forces. The mechanical properties of the nCS/A paste were increased with an increased proportion of alginate. MSCs maintained their viability after the injection, and MSCs and BMP2 gene-modified MSCs in the injectable pastes remained viable, osteodifferentiated, and yielded high alkaline phosphatase activity. By testing the ability of this injectable paste and BMP2-gene-modified MSCs for the repair of critical-sized calvarial bone defects in a rat model, we found that BMP2-gene-modified MSCs in nCS/A (nCS/A+M/B2) showed robust osteogenic activity, which resulted in consistent bone bridging of the bone defects. The vessel density in nCS/A+M/B2 was significantly higher than that in the groups of blank control, nCS/A alone, and nCS/A mixed with MSCs (nCS/A+M). These results indicate that BMP2 promotes MSCs-mediated bone formation and vascularization in nCS/A paste. Overall, the results demonstrated that the combination of injectable nCS/A paste and BMP2-gene-modified MSCs is a new and effective strategy for the repair of bone defects. PMID:22994418

  4. Chondroitin sulfate

    Science.gov (United States)

    ... in combination with glucosamine sulfate, shark cartilage, and camphor. Some people also inject chondroitin sulfate into the ... in combination with glucosamine sulfate, shark cartilage, and camphor seems to reduce arthritis symptoms. However, any symptom ...

  5. prospects and application of calcium sulfate for whisker ifber laboratory of Preparation%硫酸钙晶须纤维实验室制备及应用展望

    Institute of Scientific and Technical Information of China (English)

    牟晓红; 刘明昊; 刘俊保

    2015-01-01

    Taking gypsum as raw material in the laboratory using thermal preparation of calcium sulfate whiskers fibers, analyzes the factors in the process of preparing the slurry concentration, dispersing agent,stirring rate,temperature rising rate control and whisker fiber thermal stabilization treatment effect,and the wide application of calcium sulfate whiskers fibers in the construction industry,plastic industry, rubber industry,papermaking latex paint industry,and the prospects for the industry etc.%以石膏为原料在实验室采用热法制备硫酸钙晶须纤维,分析了制备过程中淤浆浓度、分散剂、搅拌速率、升温速率控制以及晶须纤维的热稳定化处理等影响因素,并对硫酸钙晶须纤维在建筑行业、塑料行业、橡胶行业、造纸行业、胶乳和油漆行业等的广泛应用进行了展望.

  6. Barium Sulfate

    Science.gov (United States)

    Barium sulfate is used to help doctors examine the esophagus (tube that connects the mouth and stomach), ... dimensional pictures of the inside of the body). Barium sulfate is in a class of medications called ...

  7. Glucosamine sulfate

    Science.gov (United States)

    ... to control arthritis pain. These creams usually contain camphor and other ingredients in addition to glucosamine. Glucosamine ... in combination with chondroitin sulfate, shark cartilage, and camphor for up to 8 weeks. Glucosamine sulfate can ...

  8. Effectiveness of acidic calcium sulfate with propionic and lactic acid and lactates as postprocessing dipping solutions to control Listeria monocytogenes on frankfurters with or without potassium lactate and stored vacuum packaged at 4.5 degrees C.

    Science.gov (United States)

    Nuñez de Gonzalez, Maryuri T; Keeton, Jimmy T; Acuff, Gary R; Ringer, Larry J; Lucia, Lisa M

    2004-05-01

    The safety of ready-to-eat meat products such as frankfurters can be enhanced by treating with approved antimicrobial substances to control the growth of Listeria monocytogenes. We evaluated the effectiveness of acidic calcium sulfate with propionic and lactic acid, potassium lactate, or lactic acid postprocessing dipping solutions to control L. monocytogenes inoculated (ca. 10(8) CFU/ml) onto the surface of frankfurters with or without potassium lactate and stored in vacuum packages at 4.5 degrees C for up to 12 weeks. Two frankfurter formulations were manufactured without (control) or with potassium lactate (KL, 3.3% of a 60% [wt/wt] commercially available syrup). After cooking, chilling, and peeling, each batch was divided into inoculated (four strains of L. monocytogenes mixture) and noninoculated groups. Each group was treated with four different dips: (i) control (saline solution), (ii) acidic calcium sulfate with propionic and lactic acid (ACS, 1:2 water), (iii) KL, or (iv) lactic acid (LA, 3.4% of a 88% [wt/wt] commercially available syrup) for 30 s. Noninoculated frankfurters were periodically analyzed for pH, water activity, residual nitrite, and aerobic plate counts (APCs), and L. monocytogenes counts (modified Oxford medium) were determined on inoculated samples. Surface APC counts remained at or near the lower limit of detection (dip, which indicated a residual bactericidal effect when L. monocytogenes populations were monitored over 12 weeks. L. monocytogenes numbers were also reduced, but not to the same degree in franks made without or with KL and treated with LA. These results revealed the effectiveness of ACS (bactericidal effect) or LA (bacteriostatic effect) as postprocessing dipping solutions to inhibit or control the growth of L. monocytogenes on vacuum-packaged frankfurters stored at 4.5 degrees C for up to 12 weeks. PMID:15151227

  9. Study on Crystallization Process of Calcium Sulfate Dihydrate in Gypsum Type Brine System%石膏型卤水体系硫酸钙结晶过程研究

    Institute of Scientific and Technical Information of China (English)

    唐娜; 张艳华; 任成龙; 蔡芳; 王嘉宁; 鞠兴文

    2011-01-01

    石膏型卤水体系真空蒸发制备NaCl过程中,CaSO4·2H2O对NaCl产品的纯度影响较大.研究了石膏型卤水体系中CaSO4·2H2O的结晶过程.实验研究了搅拌速率、停留时间、晶种量、温度等条件对石膏型卤水体系二水硫酸钙结晶过程的影响.研究结果表明:晶体的粒度开始随搅拌速率的增大不断增大,当搅拌速率达250r/min时,晶体粒度达到最大值77.24μm;晶体粒度同样开始时随停留时问的增大而增大,当停留时间为120min时达到最大值,此时平均粒径为70.39μm.CaSO4·2H2O晶体粒度随晶种量的增加而减小;在40℃~70℃范围内,晶体粒度开始随温度的升高而增大,在60℃时达到最大值,此时晶体的平均粒径为70.39μm,随后随温度的升高晶体的粒度逐渐降低.采用正交实验确定了石膏型卤水体系对二水硫酸钙生长影响的最佳实验条件为:温度为70℃、搅拌速率为250r/min,停留时间为120min,晶种量为3g.此时的晶体的线生长速率为2.508×10-9m/s.%Calcium suffate dehydrate has a great effect on the purity of sodium chloride product in the process of vacuum evaporation in gypsum type brine system. The crystallization process of calcium sulfate dehydrate in plaster brine system was studied in this work. The factors which influence the crystallization process of calcium sulfate dehydrate in gypsum type brine system were developed, they were stirring rate, retention time, weight of seed and temperature. The results showed that crystal product size increased with the increasing of stirring rate at the beginning and the average size of CaSO4 · 2H2O reached 77.24 μm when the stirring rate was 250 r/min. the average size of CaSO4 · 2H2O increased with increasing of retention time and temperature and it reached 70.39um when the retention time was 120 min and the temperature reached 60 ℃ respectively, after that it decreased with increasing of retention time and temperature. Orthogonal

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

    Science.gov (United States)

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

    2000-12-01

    The retarding influence of sodium poly(acrylate) (PANa) on the hydration of calcium sulfate hemihydrate (CaSO 4· {1}/{2}H 2O) was investigated. This study reports the influence of sodium poly(acrylate) on hemihydrate dissolution, on homogenous and heterogeneous gypsum (CaSO 4·2H 2O) nucleation as well as on gypsum growth. It is shown that adsorption of PANa does not hinder the dissolution of hemihydrate in the present experimental conditions. The specific interaction of PANa with gypsum can explain the oriented growth of gypsum crystal. The gypsum growth is slowed down but cannot be blocked by the adsorption of PANa. On the other hand, PANa can block the heterogeneous and homogenous gypsum nucleation. As soon as a critical surface density of PANa onto the hemihydrate surface is reached, the heterogeneous gypsum nucleation is prevented and hemihydrate hydration is indefinitely blocked. The interaction between PANa and the hemihydrate surface is of prime importance to control hydration. Also, the influence of the molecular weight of PANa on homogenous nucleation has been investigated. The precipitation of calcium polyacrylate can explain the differences between the two molecular weights used (2100 and 20 000). This work leads to the conclusion that heterogeneous nucleation is the key process that controls hydration of a system in which hemihydrate dissolution, gypsum nucleation and growth are all occurring at the same time in a continuous manner.

  11. The clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation%骨质疏松腰椎退行性疾病的手术治疗分析

    Institute of Scientific and Technical Information of China (English)

    孔祥瑞; 刘德政; 刘海峰; 杨计策; 赵志超

    2015-01-01

    ObjectiveTo explore the clinical effects of osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. Methods 82 cases of patients with lumbar degenerative dis-ease of osteoporosis word randomly divided into experiment group(41 cases) and control group(41 cases). The control group were treated by transpedicle screws fixation, the experiment group were treated by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. The time of operation, mean bleeding volum, the scores of VAS, ODI, JOA were com-pared for the two groups. ResultsThe time of operation, mean bleeding volum for the experiment group were better than the control group; There was no significant difference on the scores of VAS, ODI, JOA; The scores of VAS, ODI for the experiment group were lower than the control group postoperation for 1 week, 2 months, 12 months; The scores of JOA for the experiment group were higher than the control group postoperation for 1 week, 2 months, 12 months. ConclusionIt can improve the scores of VAS, ODI, JOA for the patients with osteoporosis of lumbar degenerative disease by injectable calcium sulfate bone cement to strengthen pedicle screw internal fixation. It is worthy of clinical promotion.%目的:探讨可注射硫酸钙骨水泥强化椎弓根钉内固定治疗骨质疏松腰椎退行性疾病的临床疗效。方法:按照随机数字表法将我院收治的82例骨质疏松腰椎退行性疾病患者均分为实验组和对照组,对照组给予单纯椎弓根内固定治疗,实验组给予可注射硫酸钙骨水泥强化椎弓根钉内固定治疗。比较两组患者手术时间、术中出血量以及治疗前后疼痛视觉模拟评分(VAS)、Oswestry 功能障碍指数(ODI)、JOA 腰椎病疗效评分变化情况。结果:实验组患者手术时间和术中出血量显著高于对照组;两组患者术前 VAS 评分、ODI 评分、JOA

  12. Congenital fibrosarcoma in complete remission with Somatostatin, Bromocriptine, Retinoids, Vitamin D3, Vitamin E, Vitamin C, Melatonin, Calcium, Chondroitin sulfate associated with low doses of Cyclophosphamide in a 14-year Follow up.

    Science.gov (United States)

    Di Bella, Giuseppe; Toscano, Rosilde; Ricchi, Alessandro; Colori, Biagio

    2015-01-01

    At birth, a male child presented a 6 cm tumour in the right leg. The tumour was partially removed after just 12 days. Histology showed a congenital fibrosarcoma associated with reactive lymphadenitis. A first cycle of adjuvant chemotherapy did not prevent the rapid progression of the disease. Subsequent evaluation for surgical removal raised serious concerns due to the need for a major operation involving total amputation of the right leg and hemipelvectomy. Since surgery could not exclude the possibility of disease recurrence and since the traditional cycles of chemotherapy did not offer any possibility of a cure, the parents opted for the Di Bella Method. The combined use of Somatostatin, Melatonin, Retinoids solubilized in Vit. E, Vit. C, Vit. D3, Calcium, and Chondroitin sulfate associated with low doses of Cyclophosphamide resulted in a complete objective response, still present 14 years later, with no toxicity and without the need for hospitalization, allowing a normal quality of life and perfectly normal adolescent psycho-physical development. PMID:26921571

  13. 经皮穿刺椎体后凸成形术中骨水泥与硫酸钙应用的对比%Calcium sulfate cement versus polymethylmethacrylate in percutaneous kyphoplasty

    Institute of Scientific and Technical Information of China (English)

    白明; 银和平

    2011-01-01

    BACKGROUND: Osteoporosis caused by the vertebral fractures in orthopedic clinical disease is very common; due to pain,kyphosis affects the quality of life of older persons. In recent years using balloon kyphoplasty (PKP) treatment of the disease to obtain good clinical, but its use of traditional bone cement filler has many shortcomings, and injectable calcium sulfate is a biocompatible, safe and effective bone substitute material, as the method of filling enhanced to make up for the lack of bone cement.OBJECTIVE: By analyzing and summarizing bone cement and injectable calcium sulfate in the kyphoplasty in applied research since 1975, to look for ideal filling materials for kyphoplasty.METHODS: By using "osteoporosis, percutaueous kyphoplasty (PKP), calcium sulfate cement (CSC), polymethylmethacrylate (PMMA)" as keywords, we retrieved articles published 1975-01/2009-12 included in Wanfang database and PubMed database.Irrelevant and the repetitive contents were excluded. Twenty-five documents retained for further analysis.RESULTS AND CONCLUSION: Ideal effective implants may be injection shall be of good, can precisely infuse fracture sites,and may reduce the injection pressure; they can rapidly be solidified, have enough mechanical strength, stable, immediately recover vertebral body load capacity; Solidification low temperature, can reduce heat damage to nearby tissue; A good imaging capabilities, can develop during the operation, which precisely control the location and depth of the filler; can be slowly biodegradable; Material origin is widespread, and cheaper prices. At present there is no a filling materials can completely have the above advantages. Therefore, the research to develop a kind of ideal filling materials for clinical use is an important task in the future.%背景:近几年采用球囊扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折获得很好临床疗效,其使用的传统填充物骨水泥有诸多缺点,可注射硫酸

  14. 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

    Energy Technology Data Exchange (ETDEWEB)

    Hovind, Haavard

    1997-09-22

    The work described in this report was a part of an international cooperative programme for assessment and monitoring of acidification of rivers and lakes. Two sample sets were prepared for intercomparison, one for determination of the major ions, the other for determination of aluminium fractions and unspecified organic matter. The samples were sent to 50 laboratories and 47 laboratories from 22 countries submitted results. Good agreement was found for chloride, sulfate, calcium, magnesium, sodium and the unspecific organic compounds, dissolved organic carbon and chemical oxygen demand, more than 80% being evaluated as acceptable for these analytic variables. The results for nitrate + nitrite and aluminium species did not agree well, probably because different methods were used to determine the aluminium species. On the whole, 78% of the results were within the general target accuracy of plus or minus 20%. Laboratories with results outside this accuracy should improve their methods if they want to analyse low-concentration samples. To improve the compatibility of the analytical results for aluminium fractions, it seems necessary to normalize the analytical methods and determination techniques used for these determinations. A total error of plus minus 0.2 pH units seems to be a reasonable assessment of the accuracy for pH measurements when weakly acid or neutral water samples not in CO{sub 2} equilibrium are analyzed. 7 refs., 1 fig., 34 tabs.

  15. Calcium-Ask1-MKK7-JNK2-c-Src Signaling Cascade Mediates Disruption of Intestinal Epithelial Tight Junctions by Dextran Sulfate Sodium

    Science.gov (United States)

    Samak, Geetha; Chaudhry, Kamaljit K.; Gangwar, Ruchika; Narayanan, Damodaran; Jaggar, Jonathan H.; Rao, RadhaKrishna

    2015-01-01

    Disruption of intestinal epithelial tight junctions is an important event in the pathogenesis of ulcerative colitis. Dextran sodium sulfate (DSS) induces colitis in mice with the symptoms similar to ulcerative colitis. However, the mechanism of DSS-induced colitis is unknown. We investigated the mechanism of DSS-induced disruption of intestinal epithelial tight junctions and barrier dysfunction in Caco-2 cell monolayers in vitro and mouse colon in vivo. DSS treatment resulted in disruption of tight junctions, adherens junctions and actin cytoskeleton leading to barrier dysfunction in Caco-2 cell monolayers. DSS induced a rapid activation of c-jun N-terminal kinase (JNK), and the inhibition or knockdown of JNK2 attenuated DSS-induced tight junction disruption and barrier dysfunction. In mice, DSS administration for 4 days caused redistribution of tight junction and adherens junction proteins from the epithelial junctions, which was blocked by JNK inhibitor. In Caco-2 cell monolayers, DSS increased intracellular Ca2+ concentration, and depletion of intracellular Ca2+ by BAPTA or thapsigargin attenuated DSS-induced JNK activation, tight junction disruption and barrier dysfunction. Knockdown of Ask1 or MKK7 blocked DSS-induced tight junction disruption and barrier dysfunction. DSS activated c-Src by a Ca2+ and JNK-dependent mechanism. Inhibition of Src kinase activity or knockdown of c-Src blocked DSS-induced tight junction disruption and barrier dysfunction. DSS increased Tyr-phosphorylation of occludin, ZO-1, E-cadherin and β-catenin. SP600125 abrogated DSS-induced Tyr-phosphorylation of junctional proteins. Recombinant JNK2 induced threonine phosphorylation and auto phosphorylation of c-Src. This study demonstrates that Ca2+-Ask1-MKK7-JNK2-cSrc signaling cascade mediates DSS-induced tight junction disruption and barrier dysfunction. PMID:25377781

  16. 氨基酸聚合物/硫酸钙生物工程骨的生物相容性研究%Study on biocompatibility of poly (amino acid)/calcium sulfate composite as bioengineering bone

    Institute of Scientific and Technical Information of China (English)

    苏保; 蒋电明; 严永刚; 赵增辉; 李军

    2011-01-01

    Objective To evaluate the biocompatibility of poly ( amino acid)/calcium sulfate ( PAA/CaSO4 ) composite as bioengineering bone. Methods The PAA in the composite consists of 6-aminohexanoic acid, glycine, alanine, phenylalanine, proline, lysine, and hydroxyproline. Physiological saline lixivium of the composite was used in acute toxicity test, hemolysis test, micronucleus test, intradermal irritation test, pyrogen test, and cytotoxicity test to evaluate the biocompatibility of the material. Results The activity of mice was normal in the acute toxicity test. No animal died and no toxicity symptom or adverse effect was shown within 7 d. The average daily weight increases showed no statistically significant difference ( P > 0.05 ) between the experimental and control groups after 7 d. The hemolysis rate of the lixivium was 2.01%, which was lower than the national standard ( < 5% ). The micronucleus rates showed no statistically significant difference (P >0. 05 ) between three experimental groups and the negative control group ( each group' s micronucleus rate was between 0.4 and 0.6), and potential mutagenicity was not observed in the micronucleus test. The maximum increase of body temperature in the experimental group was 0.4 ℃, and the total body temperature increase of the three experimental animals was 1.1 ℃, which met the national standard ( < 1.4 C ). Intradermal irritation test results showed no obvious erythema, edema, or skin necrosis in the experimental and negative control groups, with a primary irritation index of 0.01 -0.02, indicating very slight irritation. In the cytotoxicity test,the relative growth rates of two experimental groups and the negative control group were all above 90%, and the toxicity of PAA/CaS04 composite lixivium was graded 0 or 1, indicating no cytotoxicity. Conclusion PAA/CaSO4 composite has good biocompatibility.%目的 评价氨基酸聚合物[poly(amino acid),PAA]/硫酸钙(calcium sulfate,CaSO4)生物工

  17. Barium Sulfate

    Science.gov (United States)

    ... using x-rays or computed tomography (CAT scan, CT scan; a type of body scan that uses ... be clearly seen by x-ray examination or CT scan. ... more times before an x-ray examination or CT scan.If you are using a barium sulfate ...

  18. Thermal decomposition of magnesium and calcium sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Roche, S L

    1982-04-01

    The effect of catalyst on the thermal decomposition of MgSO/sub 4/ and CaSO/sub 4/ in vacuum was studied as a function of time in Knudsen cells and for MgSO/sub 4/, in open crucibles in vacuum in a Thermal Gravimetric Apparatus. Platinum and Fe/sub 2/O/sub 3/ were used as catalysts. The CaSO/sub 4/ decomposition rate was approximately doubled when Fe/sub 2/O/sub 3/ was present in a Knudsen cell. Platinum did not catalyze the CaSO/sub 4/ decomposition reaction. The initial decomposition rate for MgSO/sub 4/ was approximately 5 times greater than when additives were present in Knudsen cells but only about 1.5 times greater when decomposition was done in an open crucible.

  19. Calcium - urine

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003603.htm Calcium - urine To use the sharing features on this ... enable JavaScript. This test measures the amount of calcium in urine. All cells need calcium in order ...

  20. 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 ...

  1. Calcium Oscillations

    OpenAIRE

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

    2011-01-01

    Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlyin...

  2. Calcium sulfate cement augments transient stability of pedicle screw in osteoporotic vertebral body%硫酸钙骨水泥增强椎弓根螺钉置入骨质疏松椎体的瞬时稳定性

    Institute of Scientific and Technical Information of China (English)

    朱爱国; 张烽; 葛勇; 曹涌; 张弛; 陈云

    2014-01-01

    BACKGROUND:Poor implant anchorage in osteoporotic bone impacts its stability and requires the new solutions for the treatment. The augmentation technique with bone cements or bone substitutes is one strategy for the solutions. OBJECTIVE:To evaluate the transient stability of pedicle screw augmented using calcium sulfate cement in osteoporotic vertebral body. METHODS:Fresh calf lumbar vertebrae were selected to measure bone density, and then classified into four groups:the group by pedicle screw in normal vertebral body;the group by pedicle screw augmented using calcium sulfate cement in normal vertebral body;the group by pedicle screw in osteoporotic vertebral body;the group by pedicle screw augmented using calcium sulfate cement in osteoporotic vertebral body. Pedicle screw of equal specification was twisted into the tested pedicle of vertebral arch. The maximum axial screw pul-out strength and the maximum energy required to failure were recorded so as to assess the transient stability of pedicle screw augmented using calcium sulfate cement. RESULTS AND CONCLUSION:The maximum screw pul-out strength and the maximum energy required to failure were significantly less in osteoporotic vertebral body compared with normal vertebral body (P<0.05). The maximum screw pul-out strength and the maximum energy required to failure after augmentation using calcium sulfate cement were significantly increased (P<0.05). The maximum screw pul-out strength and the maximum energy required to failure after augmentation using calcium sulfate cement were identical between normal group and osteoporosis group. These results suggested that calcium sulfate cement could effectively increase the transient stability of pedicle screw. Calcium sulfate cement is effective in augmenting fixation in osteoporotic bone, and has potential in clinical application.%背景:由于内固定在骨质疏松骨上锚着力较差影响了其稳定性,因此需要新的固定方法,使用骨水泥或骨

  3. α-半水硫酸钙/辛伐他汀/万古霉素复合材料抗菌和细胞毒性作用的研究%Antibacterial properties and cytotoxicity of alpha half water calcium sulfate/simvastatin/vancomycin composite materials

    Institute of Scientific and Technical Information of China (English)

    陈建民; 曹华; 刘方刚; 柯荣军; 端礼荣

    2013-01-01

    [ Objective ] Escherichia coli and staphylococcus aureus, the pseudomonas aeruginosa by alpha half water calcium sulfate/simvastatin/vancomycin composite materials, and the cytotoxicity of new osteoblast cells in mice by in vitro were studied. [ Methods ] With the qualitative and quantitative of bacteria inhibition growth experiments, the diameters and antibacterial rates of Staphylococcus aureus ATCC25923, escherichia coli ATCC25922, pseudomonas aeruginosa ATCC27853 were determined under the affection of contained different concentrations of alpha half water calcium sulfate/simvastatin/vancomycin composite materials. The cytotoxicity tests of the alpha half water calcium sulfate/simvastatin/vancomycin composite materials on the new osteoblast cells in mice was made to evaluate the saftywith MTT cytotoxicity assay. [Results] Containing 5, 10, 20 u,g/ml alpha half water calcium sulfate/simvastatin/vancomycin composite materials for newborn mice osteogenesis cell concentration - effect relations on staphylococcus aureus and escherichia coli bacteriostatic circle diameter were 28, 30, 33 mm and 24, 23, 25 mm, including 0.2%, 0.4%, 8%, 1.0%. To pseudomonas aeruginosa ATCC27853 had no bacteriostasis. [ Conclusion ] The alpha half water calcium sulfate/simvastatin/vancomycin composite material leaching solution of toxic reaction level in 2 below level, are the basic of cell toxicity, they have good antibacterial effect, cells with good compatibility, and can promote bone cell proliferation and differentiation.%[目的]研究不同浓度配比α-半水硫酸钙/辛伐他汀/万古霉素复合材料的体外抗金黄色葡萄球菌、大肠埃希菌和铜绿假单胞菌的作用,以及α-半水硫酸钙/辛伐他汀/万古霉素复合材料浸提液对新生小鼠成骨细胞的毒性作用.[方法]采用细菌生长抑制的定性和定量试验测定抑菌圈直径、抑菌率;MTT法细胞毒性试验测定α-半水硫酸钙/辛伐他汀/万古霉素复合材料浸

  4. Restoration of segmental bone defects by using chitosan-coated pressed calcium sulfate pellet com-bined with rhBMP-2%壳聚糖包衣加压硫酸钙片复合重组人骨形态发生蛋白-2修复兔节段性骨缺损

    Institute of Scientific and Technical Information of China (English)

    崔旭; 张伯勋

    2009-01-01

    Objective To compare the effect of calcium sulfate pellets made by different methods in repair of segmental radial defect of rabbits. Methods Eighty white New Zealand rabbits were sub-jected to defects of middle part of the left radial bone and divided into four groups according to repair ma-terials: control group (Group A, implanted with no artificial bone substitute), uncoated pressed calcium sulfate pellets (Group B), coated pressed calcium sulfate pellets (Group C) and coated pressed calcium sulfate pellets combined with rhBMP-2 (Group D). Histologic examination and biological test were done at 4, 8 and 12 weeks after operation. The data were processed with mono-factor variance analysis. Re-sults New bone formation was found on the defected bone in Group D and Group C, with better in Group D. The bone strength test showed that the anti-bending strength was (39.6±1.7) % in Group C and (47.5±2.1) % in Group D, which were higher than (21.3±2.7) % in Group A and (23.6±3.3) % in Group B, with higher anti-bending strength in Group D than that in Group C (F = 125.3 ,P <0.01). Conclusions For restoration of segmental bone defects, chitosan-coated pressed calcium sulfate pellet shows relatively high density and slightly slow resorption, which closely coincides with the growth rate of new bone. The coated pellet combined with rhBMP-2 can enhance its osteogeneais in restoring segmental Done defects.%目的 比较不同方法 制备的硫酸钙片修复兔桡骨节段性骨缺损的效果. 方法 新西兰大白兔80只随机数字表法分为A、B、C、D组,造成左桡骨中段骨缺损,采用三种经不同方法 制备的硫酸钙片修复.A组:空白对照组;B组:加压方法 制备的硫酸钙组;C组:壳聚糖包衣的加压硫酸钙组;D组:壳聚糖包衣的复合重组人骨形态发生蛋白-2(rhBMP-2)加压硫酸钙组.术后4,8,12周进行组织学检查和生物力学测试,实验数据采用单因素方差分析. 结果 D组、C组骨缺损愈合,而

  5. Solubility of strontium sulfate in phosphoric acid and in solutions of the CaO-SrO-P2O5-H2O system

    International Nuclear Information System (INIS)

    Solubility of strontium sulfate in phosphoric acid aqueous solutions containing 5-40 wt. % P2O5 as well as in phosphoric acid solutions saturated by calcium dihydrophosphate is studied by isothermal method in the temperature range of 25-100 Deg C. It is ascertained that strontium sulfate solubility depends on phosphoric acid concentration being approximately an order lower than calcium sulfate stable phase solubility in similar conditions. In phosphoric acid solutions saturated by calcium dihydrophosphate calcium sulfate solubility is higher than that of strontium sulfate in diluted phosphoric acid solutions (up to 20 wt. % P2O5) and lower in more concentrated solutions

  6. 硫酸钙骨水泥增强骨质疏松股骨粗隆间骨折内固定的有限元分析%Finite-Element Analysis of Injectable Calcium Sulfate Bone Cement Augmentation with Dynamic Hip Screw System for the Treatment of Osteoporotic Intertrochanteric Fractures

    Institute of Scientific and Technical Information of China (English)

    于晓巍; 王楠; 汤亭亭

    2009-01-01

    通过有限元分析,研究硫酸钙对稳定型骨质疏松股骨粗隆间骨折内固定增强的影响.建立骨质疏松股骨稳定型粗隆阅骨折有限元模型,模拟动力髋螺钉(DHS)固定及硫酸钙增强的DHS固定,分析硫酸钙对DHS固定的增强效果.有限元分析显示,硫酸钙增强后,股骨头部的松质骨最大应力减少了35%,提示螺钉切割出股骨头的可能性减小;而股骨骨折面最大应力从3.7 MPa减少到1.8 MPa,提示硫酸钙增强提高了DHS固定的稳定性.研究结果表明,硫酸钙骨水泥能有效增强骨质疏松性骨折内固定的稳定性,具有较好的临床应用前景.%The mechanical performance of the dynamic hip screw (DHS) system augmented with calcium sulfate bone cement (CSC) for the fixation of stable osteoporotic intertrochanteric fracture was evaluated by means of finite element analysis (FEA). Finite element model was used to simulate the stable osteoporotic intertrochanteric fracture with DHS fixation or DHS fixation plus CSC augmentation and the stress distribution was analyzed. With cement augmentation, 35% reduction of the maximum stress was found in the femur head, suggesting reduced possibility of screw cut-outs. Maximum stress at the fracture plane was also decreased from 3.7 MPa to 1.8 MPa, which indicates improved fixation after CSC augmentation. These results indicate that calcium sulfate cement is effective in augmenting fixation in osteoporotic bone. Calcium sulfate cement has potential application in the treatment of osteoporotic fractures.

  7. Biological sulfate removal from construction and demolition debris leachate: Effect of bioreactor configuration

    International Nuclear Information System (INIS)

    Highlights: • Novel biological technique for gypsum removal from CDD. • CDDS leachate treatment performed using different sulfate reducing bioreactors. • Gypsum in CDD can be used as a source of sulfate for sulfate reducing bacteria. • High calcium concentration (1000 mg L−1) did not affect the bioreactor performance. - Abstract: Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75–85% was achieved at a hydraulic retention time (HRT) of 15.5 h. A high calcium concentration up to 1000 mg L−1 did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems

  8. Heparan sulfate in skeletal muscle development

    Energy Technology Data Exchange (ETDEWEB)

    Noonan, D.M.

    1985-01-01

    In this study, chick breast skeletal muscle cells developing in vitro from myoblasts to myotubes were found to synthesize heparan sulfate (HS), chrondroitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, unsulfated chrondroitin and hyaluronic acid in both the substratum attached material (SAM) and the cellular fraction. SAM was found to contain predominantly chrondroitin-6-sulfate and relatively little HS whereas the cellular fraction contained relatively higher levels of HS and lower levels of chrondroitin-6-sulfate. Hyaluronic acid was also a major component in both fractions with the other glycosaminoglycan isomers present as minor components. Muscle derived fibroblast cultures had higher levels of dermatan sulfate in the cell layer and higher levels of HS in the SAM fraction than did muscle cultures. The structure of the proteoglycans were partially characterized in /sup 35/SO/sub 4//sup 2 -/ radio-labeled cultures which indicated an apparent increase in the hydrodynamic size of the cell fraction heparan sulfate proteoglycan (HS PG). Myotubes incorporated /sup 35/SO/sub 4//sup 2 -/ into HS PG at a rate 3 times higher than myoblasts. The turnover rate of HS in the cellular fraction was the same for myoblasts and myotubes, with a t/sub 1/2/ of approximately 5 hours. Fibroblasts in culture synthesized the smallest HS PG, and incorporated /sup 35/SO/sub 4//sup 2 -/ into HS PG at a rate lower than that of myotubes. Studies in which fusion was reversibly inhibited with decreased medium (Ca/sup + +/) closely linked the increased synthesis of cell fraction, but not SAM fraction, HS with myotube formation. However, decreasing medium calcium appeared to cause significant alterations in the metabolism of inorganic sulfate.

  9. Heparan sulfate in skeletal muscle development

    International Nuclear Information System (INIS)

    In this study, chick breast skeletal muscle cells developing in vitro from myoblasts to myotubes were found to synthesize heparan sulfate (HS), chrondroitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, unsulfated chrondroitin and hyaluronic acid in both the substratum attached material (SAM) and the cellular fraction. SAM was found to contain predominantly chrondroitin-6-sulfate and relatively little HS whereas the cellular fraction contained relatively higher levels of HS and lower levels of chrondroitin-6-sulfate. Hyaluronic acid was also a major component in both fractions with the other glycosaminoglycan isomers present as minor components. Muscle derived fibroblast cultures had higher levels of dermatan sulfate in the cell layer and higher levels of HS in the SAM fraction than did muscle cultures. The structure of the proteoglycans were partially characterized in 35SO42- radio-labeled cultures which indicated an apparent increase in the hydrodynamic size of the cell fraction heparan sulfate proteoglycan (HS PG). Myotubes incorporated 35SO42- into HS PG at a rate 3 times higher than myoblasts. The turnover rate of HS in the cellular fraction was the same for myoblasts and myotubes, with a t/sub 1/2/ of approximately 5 hours. Fibroblasts in culture synthesized the smallest HS PG, and incorporated 35SO42- into HS PG at a rate lower than that of myotubes. Studies in which fusion was reversibly inhibited with decreased medium [Ca++] closely linked the increased synthesis of cell fraction, but not SAM fraction, HS with myotube formation. However, decreasing medium calcium appeared to cause significant alterations in the metabolism of inorganic sulfate

  10. Preliminary Study on a Novel Process for Manufacturing Soda Ash from Sodium Sulfate

    Institute of Scientific and Technical Information of China (English)

    王天贵; 李佐虎

    2004-01-01

    The purpose of this work is to find a new way for utilizing the rich sodium sulfate resource to produce soda ash. A novel process is proposed which uses aqueous dichromate solution as working medium through decomposition of calcium carbonate in aqueous sodium dichromate, complex decomposition of aqueous sodium sulfate and calcium chromate, regeneration of sodium dichromate and production of sodium bicarbonate from carbonation of aqueous sodium chromate solution, processing and utilization of byproduct calcium sulfate, and production of sodium carbonate from sodium bicarbonate. The process has the features of less corrosion and pollution and low energy consumption.

  11. Sulfated glycans in inflammation.

    Science.gov (United States)

    Pomin, Vitor H

    2015-03-01

    Sulfated glycans such as glycosaminoglycans on proteoglycans are key players in both molecular and cellular events of inflammation. They participate in leukocyte rolling along the endothelial surface of inflamed sites; chemokine regulation and its consequential functions in leukocyte guidance, migration and activation; leukocyte transendothelial migration; and structural assembly of the subendothelial basement membrane responsible to control tissue entry of cells. Due to these and other functions, exogenous sulfated glycans of various structures and origins can be used to interventionally down-regulate inflammation processes. In this review article, discussion is given primarily on the anti-inflammatory functions of mammalian heparins, heparan sulfate, chondroitin sulfate, dermatan sulfate and related compounds as well as the holothurian fucosylated chondroitin sulfate and the brown algal fucoidans. Understanding the underlying mechanisms of action of these sulfated glycans in inflammation, helps research programs involved in developing new carbohydrate-based drugs aimed to combat acute and chronic inflammatory disorders. PMID:25576741

  12. INFLUENCE OF POLYMERIC ADDITIVES ON CRYSTALLIZATION OF CALCIUM SULPHATE DIHYDRATE

    Directory of Open Access Journals (Sweden)

    Ustinova Yulia Valer’evna

    2013-04-01

    Full Text Available Currently, functional additives are widely spread in the production of inorganic dry mixtures. However, their impact on the microstructure of products, generated in the process of hardening of inorganic binders, is understudied. In this context, the goal of the work is the study of calcium sulfate dihydrate (CaSO •2H O crystallization. Super plasticizer based on sulfonated melamine-formaldehyde resin, methylcellulose and vinyl acetate, ethylene and vinyl chloride copolymer powder were selected for studies. First, pure calcium sulfate dihydrate crystals were synthesized. Then, synthesized calcium sulfate dihydrate crystals were exposed to the X-ray analysis to determine the nature of influence of polymer additives on the shape and dimensions of crystals. Possible combinations of simple forms of CaSO •2H O were identified by the X-ray analysis and the special software. Electronic microscopy analysis was performed to validate models of calcium sulfate dihydrate crystals. All plasticizers influence the crystallization of calcium sulfate dihydrate. The influence of additives on the shape and dimensions of crystals of calcium sulfate dihydrate can be explained by the fact that molecules of sulfonated melamine-formaldehyde resins, methylcellulose, and copolymers of vinyl acetate, ethylene and vinyl chloride are absorbed by crystal faces. It is proven that the method of X-ray analysis can be used to predict the shape and habitus of crystals.

  13. Restoration of segmental bone defect by calcium sulfate pellet: experiment with rabbits%三种不同方法制备的硫酸钙片植入修复桡骨节段性骨缺损的实验研究

    Institute of Scientific and Technical Information of China (English)

    崔旭; 张伯勋; 赵德伟

    2009-01-01

    Objective To compare the effects of different calcium sulfate pellets made by different methods in treating segmental defect of bone. Methods Eighty New Zealand white rabbits underwent cutting off a segment in the middle part of radius so as to establish models of radial segmental defect, and than were divided into 4 groups: Group A as control group, Group B with calcium sulfate pellet made by routine method implanted into the defect, Group C with chitosan coated pressed calcium sulfate pellet implanted into the defect, and Group D with chitosan coated pressed calcium sulfate pellet combined with recombinant human bone morthogenetic protein (rhBMP)-2 implanted into the defect:X-ray photography was done every 4 weeks to observe the new bone formation. Four, 8, and 12 weeks 5 rabbits from each group were killed. The defect segments with parts of normal bone at both ends were cut off to undergo fluorescence microscopy and biomechanic three point bending test. Results X-ray photography and histological examination showed that new bone formation of cortex and reconstruction of marrow cavity were seen in Groups D and C, especially in Group D. The new bone mineralization rate of Group D was significantly higher than that of Group C (P<0.05) which was significantly higher than that of Group B (P<0.01). The anti-bonding strength ratio of Group D was (47.5%±2.1%, significantly higher than that of Group C [(39.6±1.7)% ,F=125.3,P<0.01], and the anti-bending strength ratios of Groups D and C were both significantly higher than those of Groups B and A [(23.6±3.3)% and (21.3±2.7)%]. Conclusion Chitosan coated pressed calcium sulfate pellet shows relatively higher anti-bending strength and slightly slower resorption that closely coincide with the growth rate of new bone. It can be used to restore segmental bone defect, and particularly when combined with rhBMP-2.%目的 比较3种不同方法制备的硫酸钙片修复兔桡骨节段性骨缺损的效果.方法 采用3种经

  14. Mine water treatment with limestone for sulfate removal.

    Science.gov (United States)

    Silva, Adarlêne M; Lima, Rosa M F; Leão, Versiane A

    2012-06-30

    Limestone can be an option for sulfate sorption, particularly from neutral mine drainages because calcium ions on the solid surface can bind sulfate ions. This work investigated sulfate removal from mine waters through sorption on limestone. Continuous stirred-tank experiments reduced the sulfate concentration from 588.0mg/L to 87.0mg/L at a 210-min residence time. Batch equilibrium tests showed that sulfate loading on limestone can be described by the Langmuir isotherm, with a maximum loading of 23.7mg/g. Fixed-bed experiments were utilized to produce breakthrough curves at different bed depths. The Bed Depth Service Time (BDST) model was applied, and it indicated sulfate loadings of up to 20.0gSO(4)(2-)/L-bed as the flow rate increased from 1 to 10mL/min. Thomas, Yoon-Nelson and dose-response models, predicted a maximum particle loading of 19mg/g. Infrared spectrometry indicated the presence of sulfate ions on the limestone surface. Sulfate sorption on limestone seems to be an alternative to treating mine waters with sulfate concentrations below the 1200-2000mg/L range, where lime precipitation is not effective. In addition, this approach does not require alkaline pH values, as in the ettringite process. PMID:22541641

  15. Posterior Pedicle Fcrew Fixation Combined with Calcium Sulfate Cement of Vertebral Plasty in the Treatment of Thoracolumbar Compression Fractures%后路椎弓根钉固定结合硫酸钙骨水泥椎体成形术治疗新鲜胸腰椎压缩性骨折疗效分析

    Institute of Scientific and Technical Information of China (English)

    吐尔洪江·阿不拉; 陈新富

    2016-01-01

    目的:研究后路椎弓根钉固定术结合硫酸钙骨水泥椎体成形术治疗胸腰椎压缩性骨折的临床效果。方法整群选取2010年4月—2015年5月收治的68例胸腰椎压缩性骨折患者,随机分为A组和B组。 B组患者采用后路椎弓根钉固定术治疗,A组在B组基础上联合硫酸钙骨水泥椎体成形术治疗。于术前﹑术后3个月记录Cobb角﹑椎体前缘高度压缩率﹑椎体后缘高度压缩率,比较组间差异。结果所有患者经治疗后,其胸腰部功能指标较术前均有明显恢复。术前患者Cobb角为20°左右,术后患者降至1~6°;术前椎体前缘高度压缩率为40%左右,术后降至2%~10%之间;术前椎体后缘高度压缩率为10%左右,术后降至1%~5%之间。组间比较,术后A组Cobb角﹑椎体前缘高度压缩率﹑椎体后缘高度压缩率明显低于B组,P<0.05差异有统计学意义。结论后路椎弓根钉固定术结合硫酸钙骨水泥椎体成形术治疗胸腰椎压缩性骨折疗效良好,值得临床推广应用。%Objective To study the clinical effect of posterior pedicle screw fixation combined with calcium sulfate cement of vertebral plasty in the treatment of thoracolumbar vertebral compression fractures. Methods Group selection 68 cases collected from April in 2010 to May in 2015 of thoracolumbar fracture were randomly divided into A group and B group.B patients were treated in posterior pedicle screw fixation.Patients in the A group were treated with calcium sulfate and verte-bral bone cement angioplasty on the basis of B group.To evaluate lumbar function with the Cobb angle, anterior vertebral height compression ratio and the posterior margin of the vertebral body before treatment and after 3 months, and the differ-ence was compared between the two groups. Results All the patients chest waist function index recovered after the treat-ment. Preoperativ Cobb angle of patients is about 20, while dropped to 1 to 6 degrees after operation

  16. Sulfate metabolism in mycobacteria.

    Science.gov (United States)

    Schelle, Michael W; Bertozzi, Carolyn R

    2006-10-01

    Pathogenic bacteria have developed numerous mechanisms to survive inside a hostile host environment. The human pathogen Mycobacterium tuberculosis (M. tb) is thought to control the human immune response with diverse biomolecules, including a variety of exotic lipids. One prevalent M. tb-specific sulfated metabolite, termed sulfolipid-1 (SL-1), has been correlated with virulence though its specific biological function is not known. Recent advances in our understanding of SL-1 biosynthesis will help elucidate the role of this curious metabolite in M. tb infection. Furthermore, the study of SL-1 has led to questions regarding the significance of sulfation in mycobacteria. Examples of sulfated metabolites as mediators of interactions between bacteria and plants suggest that sulfation is a key modulator of extracellular signaling between prokaryotes and eukaryotes. The discovery of novel sulfated metabolites in M. tb and related mycobacteria strengthens this hypothesis. Finally, mechanistic and structural data from sulfate-assimilation enzymes have revealed how M. tb controls the flux of sulfate in the cell. Mutants with defects in sulfate assimilation indicate that the fate of sulfur in M. tb is a critical survival determinant for the bacteria during infection and suggest novel targets for tuberculosis drug therapy. PMID:16933356

  17. The ceric sulfate dosimeter

    DEFF Research Database (Denmark)

    Bjergbakke, Erling

    The process employed for the determination of absorbed dose is the reduction of ceric ions to cerous ions in a solution of ceric sulfate and cerous sulfate in 0.8N sulfuric acid: Ce4+→Ce 3+ The absorbed dose is derived from the difference in ceric ion concentration before and after irradiation. The...

  18. The Ettringite formation in sulfate-deficient media

    International Nuclear Information System (INIS)

    The mechanism of a direct formation of the calcium sulfo aluminate hydrates from suspension of calcium hydroxide, aluminum hydroxide and aluminum sulfate at the ambient room temperature (30±1 degree C) was studied. The sulfate concentration was kept less than the stoichiometric amount needed for the ettringite formation and the mole ratio of C/S was gradually increased to attain values of 3 and 6 at a maximum of C/A = 6, in two series of investigations (C = Ca O; A = Al2O3; H = H2O; S = SO3). The composition of the filtrates was determined and the solid phases were identified by means of XRD. It is found that ettringite crystals form with a preferential usage of the dissolved alumina as soon as a respective C/S ratio is satisfied. At a C/S - 2-2.5, limited amount of gibbsite is consumed in addition to the dissolved alumina which reaction takes place at an almost complete depletion of lime and sulfate from the solutions. At C/S = 6, the monosulfate hydrate appears together with the ettringite with a further consumption of gibbsite, free lime is detected in the solid and the solution. The results indicate that the sulfate content of the calcium sulfo aluminate hydrates is less than the stoichiometry. The formation of the calcium sulfo aluminate hydrates in cement pastes plays a dominant role in the decontamination procedures of the radioisotope wastes of low and intermediate radioactive levels

  19. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  20. Calcium Electroporation

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gibot, Laure; Madi, Moinecha;

    2015-01-01

    BACKGROUND: Calcium electroporation describes the use of high voltage electric pulses to introduce supraphysiological calcium concentrations into cells. This promising method is currently in clinical trial as an anti-cancer treatment. One very important issue is the relation between tumor cell kill...... efficacy-and normal cell sensitivity. METHODS: Using a 3D spheroid cell culture model we have tested the effect of calcium electroporation and electrochemotherapy using bleomycin on three different human cancer cell lines: a colorectal adenocarcinoma (HT29), a bladder transitional cell carcinoma (SW780......), and a breast adenocarcinoma (MDA-MB231), as well as on primary normal human dermal fibroblasts (HDF-n). RESULTS: The results showed a clear reduction in spheroid size in all three cancer cell spheroids three days after treatment with respectively calcium electroporation (p<0.0001) or...

  1. Calcium Calculator

    Science.gov (United States)

    ... Latvia - Lebanon - Libya - Lithuania - Luxembourg - Macedonia, Republic of - Malaysia - Malta - Mexico - Moldova - Morocco - Netherlands - New Zealand - Nigeria - ... and Statistics Popular content Calcium content of common foods What is Osteoporosis? The Board Introduction to Bone ...

  2. Theoretical study on the reactivity of sulfate species with hydrocarbons

    Science.gov (United States)

    Ma, Q.; Ellis, G.S.; Amrani, A.; Zhang, T.; Tang, Y.

    2008-01-01

    used in the laboratory, with most of the dissolved sulfate occurring as SO42 -, aqueous calcium sulfate ([CaSO4](aq)), and aqueous magnesium sulfate ([MgSO4](aq)). Our calculations indicate that TSR reactions that occur in natural environments are most likely to involve bisulfate ions (HSO4-) and/or magnesium sulfate contact ion-pairs ([MgSO4]CIP) rather than 'free' sulfate ions (SO42 -) or solvated sulfate ion-pairs, and that water chemistry likely plays a significant role in controlling the rate of TSR. ?? 2008 Elsevier Ltd. All rights reserved.

  3. Heparan sulfate biosynthesis

    DEFF Research Database (Denmark)

    Multhaupt, Hinke A B; Couchman, John R

    2012-01-01

    Heparan sulfate is perhaps the most complex polysaccharide known from animals. The basic repeating disaccharide is extensively modified by sulfation and uronic acid epimerization. Despite this, the fine structure of heparan sulfate is remarkably consistent with a particular cell type. This suggests...... apparatus has not been carried out in a detailed way using high-resolution microscopy. We have begun this process, using well-known markers for the various Golgi compartments, coupled with the use of characterized antibodies and cDNA expression. Laser scanning confocal microscopy coupled with line scanning...

  4. Physico-chemical transformations of sulfated compounds during the leaching of highly sulfated cemented wastes

    International Nuclear Information System (INIS)

    Cementation of sulfated evaporator concentrates leads to highly sulfated low level wastes, (ca. 25% w/w sodium sulfate solution as mix water), which exhibit the presence of U-phase, a sodium-bearing calcium monosulfphoaluminate-like phase. During the leaching of simulated highly sulfated OPC/BFS cements, cured at room temperature and containing U-phase, sodium sulfate, and ettringite, physico-chemical transformations have been pointed out (transformation of U-phase into ettringite). Samples having the same chemical composition, but cured at high temperature (maximal temperature during curing: 120 C), do not contain ettringite initially, but secondary ettringite is formed during leaching. XRD spectra point out the existence of precipitation fronts (or of phase formation fronts) varying linearly versus the square root of time. The analysis of leaching solutions has provided complementary data used in a code, the aim of which is to assess cement degradation, based on coupling between transport by diffusion and chemical reactions (DIFFUZON code). The U-phase-ettringite transformation is confirmed

  5. Holothurian Fucosylated Chondroitin Sulfate

    Directory of Open Access Journals (Sweden)

    Vitor H. Pomin

    2014-01-01

    Full Text Available Fucosylated chondroitin sulfate (FucCS is a structurally distinct glycosaminoglycan found in sea cucumber species. It has the same backbone composition of alternating 4-linked glucuronic acid and 3-linked N-acetyl galactosamine residues within disaccharide repeating units as regularly found in mammalian chondroitin sulfates. However, FucCS has also sulfated fucosyl branching units 3-O-linked to the acid residues. The sulfation patterns of these branches vary accordingly with holothurian species and account for different biological actions and responses. FucCSs may exhibit anticoagulant, antithrombotic, anti-inflammatory, anticancer, antiviral, and pro-angiogenic activities, besides its beneficial effects in hemodialysis, cellular growth modulation, fibrosis and hyperglycemia. Through an historical overview, this document covers most of the science regarding the holothurian FucCS. Both structural and medical properties of this unique GAG, investigated during the last 25 years, are systematically discussed herein.

  6. Calcium pyrophosphate arthritis

    Science.gov (United States)

    Calcium pyrophosphate dihydrate deposition disease; CPPD disease; Acute CPPD arthritis; Pseudogout ... Calcium pyrophosphate arthritis is caused by the collection of salt called calcium pyrophosphate dihydrate (CPPD). The buildup ...

  7. Biological sulfate removal from construction and demolition debris leachate: Effect of bioreactor configuration

    Energy Technology Data Exchange (ETDEWEB)

    Kijjanapanich, Pimluck, E-mail: som_cheng00@hotmail.com [Pollution Prevention and Resource Recovery Chair Group, UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Do, Anh Tien [Civil and Environmental Engineering, University of South Florida, Tampa, FL 33620 (United States); Annachhatre, Ajit P. [Environmental Engineering and Management, Asian Institute of Technology, PO Box 4, Klongluang, Pathumthani 12120 (Thailand); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino (Italy); Yeh, Daniel H. [Civil and Environmental Engineering, University of South Florida, Tampa, FL 33620 (United States); Lens, Piet N.L. [Pollution Prevention and Resource Recovery Chair Group, UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands)

    2014-03-01

    Highlights: • Novel biological technique for gypsum removal from CDD. • CDDS leachate treatment performed using different sulfate reducing bioreactors. • Gypsum in CDD can be used as a source of sulfate for sulfate reducing bacteria. • High calcium concentration (1000 mg L{sup −1}) did not affect the bioreactor performance. - Abstract: Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75–85% was achieved at a hydraulic retention time (HRT) of 15.5 h. A high calcium concentration up to 1000 mg L{sup −1} did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems.

  8. Direct Sulfation of Limestone

    DEFF Research Database (Denmark)

    Hu, Guilin; Dam-Johansen, Kim; Wedel, Stig

    2007-01-01

    %) becomes negligible. In the temperature interval from 723 K to 973 K, an apparent activation energy of about 104 kJ/mol is observed for the direct sulfation of limestone. At low temperatures and low conversions, the sulfation process is most likely under mixed control by chemical reaction and solid......The direct sulfation of limestone was studied in a laboratory fixed-bed reactor. It is found that the direct sulfation of limestone involves nucleation and crystal grain growth of the solid product (anhydrite). At 823 K and at low-conversions (less than about 0.5 %), the influences of SO2, O-2 and...... CO2 on the direct sulfation of limestone corresponds to apparent reaction orders of about 0.2, 0.2 and -0.5, respectively. Water is observed to promote the sulfation reaction and increase the apparent reaction orders of SO2 and O-2. The influence of O-2 at high O-2 concentrations (> about 15...

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

    Science.gov (United States)

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

    2004-06-01

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

  10. Formation of ettringite, Ca6Al2(SO4)3(OH)12·26H2O, AFt, and monosulfate, Ca4Al2O6(SO4)·14H2O, AFm-14, in hydrothermal hydration of Portland cement and of calcium aluminum oxide--calcium sulfate dihydrate mixtures studied by in situ synchrotron X-ray powder diffraction

    International Nuclear Information System (INIS)

    In the hydration of calcium aluminum oxide-gypsum mixtures, i.e., Ca3Al2O6, Ca12Al14O33 and CaSO4·2H2O, the reaction products can be ettringite, Ca6Al2(SO4)3(OH)12·26H2O, monosulfate, Ca4Al2O6(SO4)·14H2O, or the calcium aluminum oxide hydrate, Ca4Al2O7·19H2O. Ettringite is formed if sufficient CaSO4·2H2O is present in the mixture. Ettringite is converted to monosulfate when all CaSO4·2H2O is consumed in the synthesis of ettringite. The reactions were investigated in the temperature range 25-170 degree sign C using in situ synchrotron X-ray powder diffraction. This technique allows the study of very fast chemical reactions that are observed here under hydrothermal conditions. A new experimental approach was developed to perform in situ mixing of the reactants during X-ray data collection

  11. Calcium and bones

    Science.gov (United States)

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

  12. Get Enough Calcium

    Science.gov (United States)

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

  13. Calcium carbonate overdose

    Science.gov (United States)

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

  14. Biological sulfate removal from construction and demolition debris leachate: effect of bioreactor configuration.

    Science.gov (United States)

    Kijjanapanich, Pimluck; Do, Anh Tien; Annachhatre, Ajit P; Esposito, Giovanni; Yeh, Daniel H; Lens, Piet N L

    2014-03-30

    Due to the contamination of construction and demolition debris (CDD) by gypsum drywall, especially, its sand fraction (CDD sand, CDDS), the sulfate content in CDDS exceeds the posed limit of the maximum amount of sulfate present in building sand (1.73 g sulfate per kg of sand for the Netherlands). Therefore, the CDDS cannot be reused for construction. The CDDS has to be washed in order to remove most of the impurities and to obtain the right sulfate content, thus generating a leachate, containing high sulfate and calcium concentrations. This study aimed at developing a biological sulfate reduction system for CDDS leachate treatment and compared three different reactor configurations for the sulfate reduction step: the upflow anaerobic sludge blanket (UASB) reactor, inverse fluidized bed (IFB) reactor and gas lift anaerobic membrane bioreactor (GL-AnMBR). This investigation demonstrated that all three systems can be applied for the treatment of CDDS leachate. The highest sulfate removal efficiency of 75-85% was achieved at a hydraulic retention time (HRT) of 15.5h. A high calcium concentration up to 1,000 mg L(-1) did not give any adverse effect on the sulfate removal efficiency of the IFB and GL-AnMBR systems. PMID:24211179

  15. Sulfate attack expansion mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Müllauer, Wolfram, E-mail: wolf_m@gmx.at; Beddoe, Robin E.; Heinz, Detlef

    2013-10-15

    A specially constructed stress cell was used to measure the stress generated in thin-walled Portland cement mortar cylinders caused by external sulfate attack. The effects of sulfate concentration of the storage solution and C{sub 3}A content of the cement were studied. Changes in mineralogical composition and pore size distribution were investigated by X-ray diffraction and mercury intrusion porosimetry, respectively. Damage is due to the formation of ettringite in small pores (10–50 nm) which generates stresses up to 8 MPa exceeding the tensile strength of the binder matrix. Higher sulfate concentrations and C{sub 3}A contents result in higher stresses. The results can be understood in terms of the effect of crystal surface energy and size on supersaturation and crystal growth pressure.

  16. Calcium paradox and calcium entry blockers

    NARCIS (Netherlands)

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

    1984-01-01

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

  17. Crystal structure of tris­(piperidinium) hydrogen sulfate sulfate

    OpenAIRE

    Lukianova, Tamara J.; Kinzhybalo, Vasyl; Pietraszko, Adam

    2015-01-01

    A novel mixed hydrogen sulfate–sulfate piperidinium salt comprises three protonated piperidinium cations, one hydrogen sulfate anion and one sulfate anion in the asymmetric unit. Strong hydrogen bonds exist between the cations and the anions giving rise to a three-dimensional structure.

  18. Hydrazine Sulfate (PDQ)

    Science.gov (United States)

    ... use of hydrazine sulfate as a complementary or alternative treatment for cancer? It has been known since the early 1900s ... of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that ...

  19. Aluminum Sulfate 18 Hydrate

    Science.gov (United States)

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) of the chemical, aluminum sulfate 18 hydrate, is presented. The profile lists physical and harmful properties, exposure limits, reactivity risks, and symptoms of major exposure for the benefit of teachers and students using the chemical in the laboratory.

  20. Preliminary Study on a Novel Process for Manufacturing Soda Ash from Sodium Sulfate%一种新的芒硝制碱法实验室研究

    Institute of Scientific and Technical Information of China (English)

    王天贵; 李佐虎

    2004-01-01

    The purpose of this work is to find a new way for utilizing the rich sodium sulfate resource to produce soda ash.A novel process is proposed which uses aqueous dichromate solution as working medium through decomposition of calcium carbonate in aqueous sodium dichromate,complex decomposition of aqueous sodium sulfate and calcium chromate,regeneration of sodium dichromate and production of sodium bicarbonate from carbonation of aqueous sodium chromate solution,processing and utilization of byproduct calcium sulfate,and production of sodium carbonate from sodium bicarbonate.The process has the features of less corrosion and pollution and low energy consumption.

  1. Sulfate metabolism. I. Sulfate uptake and redistribution of acid rain sulfate by edible plants

    International Nuclear Information System (INIS)

    Sulfur is the major component of polluted air in industrialized societies. Atmospheric sulfur is converted to sulfuric acid through a series of chemical reactions which can eventually reenter many ecosystems. When edible plants are grown in soils containing varying amounts of sulfate, the roots take up and transport inorganic sulfate to the stems and leaves. The sulfate taken up by the roots and the amount transported to the stem and leaves was found to be a function of the concentration of sulfate in the soil. Inorganic sulfate taken up by a corn plant seedling can be rapidly converted to organic sulfate by the root system. Nine days after one of a pair of pea plants was inoculated with artificial acid rain sulfate (dilute H235SO4) it was found that the sulfate was translocated not only in the inoculated plant, but also to the uninoculated pea plant in the same container. Also, when the leaves of a mature potato plant were inoculated with artificial acid rain sulfate it was found that the sulfate was translocated into the edible potatoes. Fractionation of the potatoes showed that most of the sulfate was water soluble of which 30% was inorganic sulfate and 70% was in the form of organic sulfur. One third of the non-water soluble translocated acid rain sulfate was equally divided between lipid and non-lipid organic sulfur of the potato. 9 references, 2 figures, 5 tables

  2. A Large Chondroitin Sulfate Proteoglycan, Versican, in Porcine Predentin

    OpenAIRE

    Okahata, Saori; Yamamoto, Ryuji; Yamakoshi, Yasuo; Fukae, Makoto

    2011-01-01

    Proteoglycans and their constituent glycosaminoglycan (GAG) have been proposed to be involved in the inhibition of mineralization in unmineralized tissue, predentin. Among the proteoglycans secreted by odontoblasts, we focused on the large chondroitin sulfate proteoglycan, versican, for its large binding capacity for calcium ions. The aims of this study were the determination of the full-length sequence and splicing variants of the porcine versican, and the detection of versican in the porcin...

  3. Hydration and dimensional stability of calcium aluminate cement based systems

    OpenAIRE

    Bizzozero, Julien

    2014-01-01

    Calcium aluminate cements (CAC) are often used in combination with calcium sulfate and Portland cement for special applications where rapid setting, rapid drying and shrinkage compensation are required. A growing fraction of the clinker, which has the highest CO2 intensity, is being replaced by supplementary cementitious materials (SCM). These SCM are usually from industrial by-products such as slag, fly ashes or can simply be raw materials such as limestone. This project aims at replacing th...

  4. Radioimmunoassay of dehydroepiandrosterone sulfate

    International Nuclear Information System (INIS)

    The development of a radioimmunological method for the measurement of dehydroepiandrosterone sulfate in serum is described. For the immunization of rabbits, a DHA-3-hemissuccinate-bovine serum albumin conjugate was synthetized and a highly specific anti-serum was produced. The method developed requires only simple dilution prior to assay and the normal values for the different age groups were determined in 146 normal individuals. (Author)

  5. Calcium and bones (image)

    Science.gov (United States)

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

  6. Coronary Calcium Scan

    Science.gov (United States)

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

  7. Calcium hydroxide poisoning

    Science.gov (United States)

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

  8. Calcium source (image)

    Science.gov (United States)

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

  9. Calcium in diet

    Science.gov (United States)

    Diet - calcium ... Calcium is one of the most important minerals for the human body. It helps form and maintain healthy teeth and bones. A proper level of calcium in the body over a lifetime can help ...

  10. Calcium Pyrophosphate Deposition (CPPD)

    Science.gov (United States)

    ... Patient / Caregiver Diseases & Conditions Calcium Pyrophosphate Deposition (CPPD) Calcium Pyrophosphate Deposition (CPPD) Fast Facts The risk of ... young people, too. Proper diagnosis depends on detecting calcium pyrophosphate crystals in the fluid of an affected ...

  11. Sulfation of chondroitin. Specificity, degree of sulfation, and detergent effects with 4-sulfating and 6-sulfating microsomal systems

    International Nuclear Information System (INIS)

    Microsomal preparations from chondroitin 6-sulfate-producing chick embryo epiphyseal cartilage, and from chondroitin 4-sulfate-producing mouse mastocytoma cells, were incubated with UDP-[14C]glucuronic acid and UDP-N-acetylgalactosamine to form non-sulfated proteo[14C]chondroitin. Aliquots of the incubations were then incubated with 3'-phosphoadenylylphosphosulfate (PAPS) in the presence or absence of various detergents. In the absence of detergents, there was good sulfation of this endogenous proteo[14C]chondroitin by the original microsomes from both sources. Detergents, with the exception of Triton X-100, markedly inhibited sulfation in the mast cell system but not in the chick cartilage system. These results indicate that sulfation and polymerization are closely linked on cell membranes and that in some cases this organization can be disrupted by detergents. When aliquots of the original incubation were heat inactivated, and then reincubated with new microsomes from chick cartilage and/or mouse mastocytoma cells plus PAPS, there was no significant sulfation of this exogenous proteo[14C] chondroitin with either system unless Triton X-100 was added. Sulfation of exogenous chondroitin and chondroitin hexasaccharide was compared with sulfation of endogenous and exogenous proteo[14C]chondroitin. Sulfate incorporation into hexasaccharide and chondroitin decreased as their concentrations (based on uronic acid) approached that of the proteo[14C]chondroitin. At the same time, the degree of sulfation in percent of substituted hexosamine increased. However, the degree of sulfation did not reach that of the endogenous proteo[14C]chondroitin. Hexasaccharide and chondroitin sulfation were stimulated by the presence of Triton X-100. However, in contrast to the exogenous proteo[14C]chondroitin, there was some sulfation of hexasaccharide and chondroitin in the absence of this detergent

  12. Behaviour of cementitious materials: sulfates and temperature actions

    International Nuclear Information System (INIS)

    The research work presented in this Ph.D. thesis is related to the nuclear waste underground repository concept. Concrete could be used in such a repository, and would be subjected to variations of temperature in presence of sulfate, a situation that could induce expansion of concrete. The research was lead in three parts: an experimental study of the possibility of an internal sulfate attack on mortars; an experimental study and modeling of the chemical equilibriums of the CaO-SiO2-Al2O3-SO3-H2O system; and a modeling of the mechanisms of internal and external sulfate attacks, and the effect of temperature. The results show that mortars can develop expansions after a steam-cure during hydration, but also when a long steam-cure is applied to one-year-old mortars, which is a new point. Ettringite precipitation can be considered as responsible for these expansions. The experimental study of the CaO-SiO2-Al2O3-SO3-H2O system clarified the role of Calcium Silicate Hydrates (C-S-H) on chemical equilibriums of cementitious materials. Sulfate sorption on C-S-H has been studied in detail. The quantity of sulfate bound to the C-S-H mainly depends on the sulfate concentration in solution, on the Ca/Si ratio of the C-S-H and is not significantly influenced by temperature. Aluminium inclusion in the C-S-H seems to be a significant phenomenon. Temperature increases the calcium sulfo-aluminate solubilities and thus increases sulfates concentration in solution. A modeling of the chemical system is proposed. Simulations of external sulfate attack (15 mmol/L of Na2SO4) predict ettringite precipitation at 20 and 85±C. Simulation of internal sulfate attack was performed at a local scale (a hydrated cement grain). An initial inhomogeneity can lead, after a thermal curing at 85±C, to ettringite precipitation in zones originally free from ettringite. This new-formed ettringite could be the origin of the expansions. (author)

  13. 注射型可吸收聚氨基酸/硫酸钙复合材料动物体内降解吸收及促成骨作用%In vivo degradation, absorption and osteogenesis of injectable and absorbable polyamine acid/calcium sulfate composites

    Institute of Scientific and Technical Information of China (English)

    姜勇; 张帅; 周勇; 闵理; 易敏; 段宏; 屠重棋; 严永刚

    2012-01-01

    背景:注射型人工骨可经皮穿刺注射植入体内,对机体创伤较小,同时该型材料可以任意塑形,能较好地充填骨缺损,但目前临床上尚无在体内能完全降解吸收且具有较好促成骨作用的注射型人工骨产品.目的:评估注射型可吸收聚氨基酸/硫酸钙复合材料(硫酸钙含量70%)动物体内的降解吸收及促成骨作用,观察其修复骨缺损的能力.方法:取48只新西兰大白兔,在股骨外髁处制备直径为5 mm、深10 mm的骨缺损模型,以随机数字表法分为实验组和对照组,实验组将注射型可吸收聚氨基酸/硫酸钙复合材料植入骨缺损处,对照组未予干预.结果与结论:X射线平片示:实验组骨缺损逐渐被骨痂填充,术后16周,骨缺损处恢复正常松质骨密度,塑形完成;对照组骨缺损处修复不明显.组织学检查(苏木精-伊红、MASSON染色)示:术后4周,材料开始降解,新生原始骨小梁长入材料内;术后12周,编织骨开始转化为板层骨;术后16周,材料完全被降解吸收,新生骨组织完全修复骨缺损.结果显示注射型聚氨基酸/硫酸钙复合材料在动物内能够完全降解、吸收,具备一定的成骨活性,可望用作骨修复材料.%BACKGROUND: With fewer traumas to the body, injectable artificial bone can be implanted into the body through the percutaneous injection. Meanwhile, the material can be any shape to fill bone defects. But now in clinic, there is no injectable artificial bone substitute product with the better ability of bone formation, which can be completely degraded and absorbed in vivo. OBJECTIVE: To evaluate the degradation, absorption and osteogenesis in vivo ability of injectable and absorbable polyamine acid/calcium sulfate (PAA/CS) composites (containing 70% calcium sulfate), and to observe the ability to repair bone defects. METHODS: A 5 mm×10 mm size bone defect model was made on the femoral condyle of 48 New Zealand white rabbits, which were

  14. Enhanced sulfate reduction with acidogenic sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Sulfate reduction in a continuous flow, acidogenic reactor using molasses wastewater as the carbon source was studied at varying chemical oxygen demand/sulfate (COD/SO42-) ratios. At a critical COD/SO42- ratio of 2.7, neither COD nor sulfate were in excess for extra production of ethanol or acetate in the reactor. An acetic-type microbial metabolism was established with sulfate-reducing bacteria (SRB) significantly consuming hydrogen and volatile fatty acids produced by acidogenic bacteria and hydrogen producing acetogens in degrading COD, thereby yielding sulfate removal rate >94.6%. A low critical COD/SO42- ratio of 1.6 was also observed with the enriched ASRB population in reactor which overcomes the barrier to the treatment capability of sulfate-laden wastewater treatment with limited COD supply

  15. Effect of vitamin D supplementation and magnesium sulfate therapy in pre-eclampsia

    Directory of Open Access Journals (Sweden)

    Neeru Bhaskar

    2014-04-01

    Full Text Available Background: Vitamin D insufficiency has been associated with several adverse health outcomes, including pregnancy outcomes, and is increasingly recognised as a public health concern. It is responsible for approximately 50,000 maternal deaths yearly worldwide, 25% of all cases of fetal growth restriction, and 15% of preterm births in developed countries. Objective: Vitamin D and magnesium sulfate act by altering the calcium levels so this study was conducted to see if vitamin D supplementation has any additive role to magnesium sulfate treatment in preeclampsia and in preventing its progression to eclampsia. Materials and Methods: This cross sectional study was conducted in the Department of Biochemistry, in collaboration with Department of Obstetrics and Gynecology, at MMIMSR, Mullana (Ambala, Haryana, India. One hundred and fifty pregnant females attending the Obstetrics clinic were selected for the study and were divided into three groups of fifty each. Group I (Control: Normotensive healthy pregnant females, Group II: Preeclamptic patients receiving magnesium sulfate therapy and Group III: Preeclamptic patients receiving magnesium sulfate therapy along with vitamin D supplementation (33000 IU once every two weeks, orally after 28 weeks up to 36 weeks. The samples were analysed for serum total calcium, ionized calcium, serum phosphorous, serum magnesium, serum albumin, serum alkaline phosphatase, serum creatinine and serum uric acid. Results: Mean levels of total calcium, ionised calcium, phosphorous, magnesium, albumin, alkaline phosphatase, creatinine and uric acid before and after delivery were calculated in all the three groups. Serum calcium (total and ionised, albumin and magnesium were decreased in preeclamptic women whereas serum phosphorous and uric acid were increased in preeclamptic. Vitamin D supplementation improved calcium status, uric acid level and albumin level were also improved. Conclusion: Vitamin D supplementation in early

  16. Crystal structure of tris­(piperidinium) hydrogen sulfate sulfate

    OpenAIRE

    Tamara J. Lukianova; Vasyl Kinzhybalo; Adam Pietraszko

    2015-01-01

    In the title molecular salt, 3C5H12N+·HSO4−·SO42−, each cation adopts a chair conformation. In the crystal, the hydrogen sulfate ion is connected to the sulfate ion by a strong O—H...O hydrogen bond. The packing also features a number of N—H...O hydrogen bonds, which lead to a three-dimensional network structure. The hydrogen sulfate anion accepts four hydrogen bonds from two cations, whereas the sulfate ion, as an acceptor, binds to five separate piperidinium cations, forming seven hydrogen ...

  17. Binding of heparan sulfate to Staphylococcus aureus.

    OpenAIRE

    Liang, O D; Ascencio, F; Fransson, L A; Wadström, T

    1992-01-01

    Heparan sulfate binds to proteins present on the surface of Staphylococcus aureus cells. Binding of 125I-heparan sulfate to S. aureus was time dependent, saturable, and influenced by pH and ionic strength, and cell-bound 125I-heparan sulfate was displaced by unlabelled heparan sulfate or heparin. Other glycosaminoglycans of comparable size (chondroitin sulfate and dermatan sulfate), highly glycosylated glycoprotein (hog gastric mucin), and some anionic polysaccharides (dextran sulfate and RNA...

  18. Removal of sulfate from high-strength wastewater by crystallisation.

    Science.gov (United States)

    Tait, Stephan; Clarke, William P; Keller, Jurg; Batstone, Damien J

    2009-02-01

    Sulfate causes considerable problems in anaerobic digesters, related to generation of sulfides, loss of electrons (and hence methane), and contamination of gas streams. Removal of sulfides is generally expensive, and still results in methane losses. In this paper, we evaluate the use of precipitation for low-cost sulfate removal, in highly contaminated streams (>1 gS L(-1)). The main precipitate assessed is calcium sulfate (gypsum), though the formation of complex precipitates such as jarosite and ettringite to remove residual sulfate is also evaluated. The four main concerns in contaminated wastewater are:- high solubility, caused by high ion activity and ion pairing; slow kinetics; inhibition of nucleation; and poisoning of crystals by impurities, rendering product unsuitable for reuse as seed. These concerns were addressed through batch experiments on a landfill wastewater with a similar composition to other sulfate rich industrial wastewaters (high levels of organic and inorganic contaminants). Crystallisation rates were rapid and comparable to what is observed by others for pure solutions (2-5 h). The kinetics of crystallisation showed a 2nd order dependence on supersaturation, which have implications for crystalliser design, as discussed in the paper. No spontaneous nucleation was observed (seed was required). Seed poisoning did not occur, and product crystals were as effective as pure seed. Solubility was increased by an order of magnitude compared to a pure solution (2.6x10(-3) M2 vs. 0.22x10(-3) M2). As evaluated using equilibrium modelling, this was caused equally by non-specific ion activity, and specific ion pairing. Jarosite and ettringite could not be formed at reasonable pH and temperature levels. Given the lack of complex precipitates, and relatively high solubility, gypsum crystallisation cannot practically be used to remove sulfate to very low levels, and gas-sulfide treatment will likely still be required. It can however, be used for low

  19. Calcium and Vitamin D

    Science.gov (United States)

    ... Home › Patients › Treatment › Calcium/Vitamin D Calcium/Vitamin D Getting enough calcium and vitamin D is essential ... counter medications and calcium supplements. What is Vitamin D and What Does it Do? Vitamin D plays ...

  20. Effect of fly ash on the optimum sulfate of Portland Cement

    Science.gov (United States)

    Niemuth, Mark D.

    Calcium sulfate is typically added to ordinary portland cement (OPC) clinker during grinding to prevent flash set and to improve early-age strength development without causing volume instabilities. Recent changes to ASTM C150, Standard Specification for Portland Cement, have enabled greater flexibility in determining optimum sulfate levels in portland cement by not requiring ASTM C563, Approximation of Optimum SO3 in Hydraulic Cement Using Compressive Strength, to be used in setting sulfate target levels. ASTM C563 requires strength testing using only the hydraulic cement, which is not always indicative of the optimum sulfate for field use, since supplementary materials (e.g., fly ash) may be used by the concrete producer. Adding additional sulfate to account for the sulfate demand of fly ashes can enable an improvement in the early age strength for cement-fly ash systems and decrease in problems that may be attributed to OPC-admixture-fly ash incompatibility such as abnormal setting and slow strength gain. This thesis provides experimental data on the strength development and heat release during early hydration for cement-fly ash systems with different sulfate levels. The thesis focused on high calcium fly ashes, but low calcium fly ash was also tested. It is demonstrated that some fly ashes have their own sulfate demand and when these ashes are used in cement-fly ash blends there is effectively an increase in the optimal sulfate level that could be used for the OPC. It is also shown that optimum sulfate determined by heat of hydration measured with isothermal calorimetry is similar to the optimum sulfate determined by compressive strength at 1 day. Using isothermal calorimetry can result in substantial time and cost savings at plants for determining the optimal sulfate content. Theories for the mechanisms that drive the differences in sulfate demand in OPC are reviewed. These theories are adapted for OPC-fly ash blends and are outlined, tested and discussed. The

  1. Importance of Calcium

    OpenAIRE

    TANDOĞAN, Berivan; ULUSU, N. Nuray

    2005-01-01

    Calcium is the most abundant mineral in the body. Calcium regulates many cellular processes and has important structural roles in living organisms. Skeletal muscle structure and function, polymerisation of fibrin and the conduction of impulses in the nervous system are regulated by calcium. Calcium is an important intracellular messenger in protozoa, plants, and animals. Calcium-transporting systems which are located in the plasma membrane and in the organelles, regulate the ionic concentrati...

  2. Versatic 10萃取体系和由Versatic 10和Cyanex 301组成的复配体系萃取分离硫酸盐溶液中镍钴和钙镁%Recovery of cobalt and nickel in the presence of magnesium and calcium from sulfate solutions by Versatic 10 and mixtures of Versatic 10 and Cyanex 301

    Institute of Scientific and Technical Information of China (English)

    管青军; 孙伟; 周桂英; 刘佳鹏; 殷志刚

    2016-01-01

    The extraction and stripping characteristics of Versatic 10 and its mixtures with Cyanex 301 were investigated for the recovery of cobalt and nickel from sulfate solutions containing magnesium and calcium. The optimum extraction factors of Versatic 10 were initial pH of 2.5, O/A ratio of 1/3, and saponification rate of 60%. The loaded Versatic 10 was stripped by using 2 mol/L H2SO4 at O/A ratio of 1/1. The optimum volume ratio of Versatic 10 to Cyanex301 was 7/3 in the mixtures, which could effectively reduce the equilibrium pH to 3.50. And the loaded mixtures were stripped by using 2 mol/L H2SO4at O/A ratio of 1/2. The reaction principle of Versatic10 and metal ions is an ion exchange reaction. However, in the extraction reaction of and metal ions, besides the ion exchange reaction, the strong coordination effect between Cyanex 301 and metal ions also exists, which is much weakened in the extraction reaction of the mixtures and metal ions.%考察萃取剂Versatic 10以及它和Cyanex 301组成的复配萃取体系从含有镁钙离子的硫酸盐溶液中萃取分离镍钴离子的萃取和反萃特征。Versatic 10萃取分离镍钴和钙镁的最佳条件为初始pH值为2.5、油水体积比O/A为1/3、皂化率为60%。Versatic 10的负载有机相用2 mol/L的硫酸溶液以O/A为1/1进行反萃。复配萃取体系中Versatic 10和Cyanex 301的最佳体积比为7/3,复配体系能有效降低镍钴和钙镁萃取分离的平衡pH值至3.50,当O/A为1/2时,2 mol/L的硫酸溶液可以对负载有机相进行有效反萃。Versatic 10与金属离子进行萃取的反应机理为离子交换,而Cyanex 301与金属离子之间不仅有离子交换还有强烈的配位效应,这种配位效应在复配体系与金属离子萃取过程中被大大削弱。

  3. Pedicle screw reduction and fixation combined with calcium sulfate cement vertebroplasty in the treatment of thoracolumbar fractures%椎弓根钉复位固定结合注射型硫酸钙椎体成形术治疗胸腰椎骨折

    Institute of Scientific and Technical Information of China (English)

    魏力今; 周业金; 刘艺明; 潘良春; 李春; 何高

    2011-01-01

    目的 总结椎弓根钉复位固定结合注射型硫酸钙(CSC) 椎体成形术治疗胸腰椎骨折的方法与疗效.方法 对23 例(25椎)胸腰椎骨折采用切开复位椎弓根钉固定,用特定注射器经伤椎椎弓根穿刺注入CSC进行椎体成形术治疗,影像学评估术前、术后及取钉12个月后矢状位指数(SI)及椎体前、后缘高度压缩率变化.结果 平均每个椎体注入CSC 5.34 ml,6例术中发生椎旁渗漏,无椎管内渗漏,术后患者神经功能Frankel分级较术前提高1~2级(P<0.05).术后8~12周影像学结果 提示,硫酸钙在椎体内完全消失,被正常骨组织吸收.术后及取钉12个月后SI角及椎体前、后缘高度压缩率均较术前有明显改善(P<0.01),术后至取钉12个月后椎体前缘无明显丢失,但椎体后缘有少量丢失(P<0.05).本组无椎弓根钉失败病例.结论 椎弓根钉复位固定结合CSC椎体成形术治疗胸腰椎骨折,能使复位后的伤椎恢复其完整形态及椎体强度,提高胸腰椎骨折的临床疗效,其方法简便、安全,近期疗效满意.%Objective To investigate the method and effect of pedicle screw reduction and fixation combined with calcium sulfate cement ( CSC ) vertebroplasty in the treatment of thoracolumbar fractures. Methods 23 cases ( 25 vertebrae ) with thoracolumbar fractures were treated with pedicle screw sagittal index( SI ) angle reduction and fixation combined with CSC vertebroplasty. According to imaging, we evaluated the change SI angle and compression ratio of vertebral body at the time of preoperation, postoperation and 12 months later. Results Each vertebra was injected with 5. 34 ml CSC on average. 6 cases got paravertebral leakage. No vertebral canal leakage was found.Frankel grading of neural function was improved. CSC disappeared in 8 ~12 weeks and substituted by bone. In the postoperative and 12 months films, the SI angle, vertebral height were improved ( P <0. 01 ). The anterior height did not

  4. SULFATE RESISTANCE MECHANISM OF HIGH-PERFORMANCE CONCRETE CONTAINING NCI

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    It is found that the incorporation of Nitrite Corrosion Inhibitor (NCI) greatly weakens the resistance of mixtures to sulfate attack.To study the mechanism of this phenomenon,in this paper,the influence of NCI additionon on the cement paste and microstructure change of high performance concrete specimens is studied by means of quantitative XRD,SEM tests.The results demonstrate that the incorporation of NCI accelerates the formation of calcium hydroxide and ettringite crystals,and weakens the pore refinement effect caused by the secondary hydration reaction of fly ash and microsilica.At the age up to one year,the relative crystal quantity in mixture containing NCI is always higher than that in control mixture.The reasons for the degradation in sulfate resisitance of mixtures may be attributed to the increase and stability of the calcium hydroxide and ettringite crystals formed and the weakening of secondary hydration reaction.Based on the results,conclusion can be drawn that NCI should be used cautiously in practical engineering where high resistance to sulfate attack is required.

  5. Magnesium sulfate as a key mineral for the detection of organic molecules on Mars using pyrolysis

    Science.gov (United States)

    François, P.; Szopa, C.; Buch, A.; Coll, P.; McAdam, A. C.; Mahaffy, P. R.; Freissinet, C.; Glavin, D. P.; Navarro-Gonzalez, R.; Cabane, M.

    2016-01-01

    Pyrolysis of soil or rock samples is the preferred preparation technique used on Mars to search for organic molecules up today. During pyrolysis, oxichlorines present in the soil of Mars release oxidant species that alter the organic molecules potentially contained in the samples collected by the space probes. This process can explain the difficulty experienced by in situ exploration probes to detect organic materials in Mars soil samples until recently. Within a few months, the Curiosity rover should reach and analyze for the first time soils rich in sulfates which could induce a different behavior of the organics during the pyrolysis compared with the types of soils analyzed up today. For this reason, we systematically studied the pyrolysis of organic molecules trapped in magnesium sulfate, in the presence or absence of calcium perchlorate. Our results show that organics trapped in magnesium sulfate can undergo some oxidation and sulfuration during the pyrolysis. But these sulfates are also shown to protect organics trapped inside the crystal lattice and/or present in fluid inclusions from the oxidation induced by the decomposition of calcium perchlorate and probably other oxychlorine phases currently detected on Mars. Trapped organics may also be protected from degradation processes induced by other minerals present in the sample, at least until these organics are released from the pyrolyzed sulfate mineral (~700°C in our experiment). Hence, we suggest magnesium sulfate as one of the minerals to target in priority for the search of organic molecules by the Curiosity and ExoMars 2018 rovers.

  6. Sulfated Macromolecules as Templates for Calcite Nucleation and Growth

    Science.gov (United States)

    David, M.; Passalacqua, K.; Neira, A. C.; Fernandez, M. S.

    2003-12-01

    Mineralization of egg and seashells is controlled by an intimate association of inorganic materials with organic macromolecules. Among them, particular polyanionic sulfated macromolecules referred to as proteoglycans have been described to be involved in the calcification of these biominerals. The sulfated moieties of the proteoglycans are part of polymer chains constituted of building-blocks of disaccharide units, referred to as sulfated glycosaminoglycans (GAGs), which are covalently attached to a protein core. By using a sitting drop crystallization assay under controlled conditions of time, pH and reactants concentration, we have tested several sulfated and non-sulfated GAGs (i.e.: dermatan and keratan sulfate, hyaluronic acid and heparin), differing in their sulfonate and carboxylate degree and pattern, in their ability to modify calcium carbonate crystal morphology as observed under scanning electron microscopy. Without the addition of GAGs, regular \\{104\\} rhombohedral calcite crystals were obtained. When hyaluronic acid (HA), a non-sulfated but carboxylated GAG, was added, 20 mm long piles of unmodified calcite crystals were observed. When desulfated dermatan, which is an epimeric form of HA but shorter polymer, having their carboxylate groups in an inverted configuration, was added, isolated rhombohedral \\{104\\} calcite crystals showing rounded corners with planes oriented parallel to the c axis were observed. When dermatan sulfated was added, isolated calcite crystals exhibit a columnar morphology as a \\{hk0\\} cylinder with three \\{104\\} faces forming a cap at both ends. Heparin activity depends on the fraction added. Fast-moving heparin fraction (FM), is an undersulfated, low-molecular-weight heterogeneous polymer, while slow-moving heparin fraction (SM) is an high-molecular-weight homogeneous polymer rich in trisulfated-disaccharide units. When FM was added, isolated calcite crystals displayed rhombohedrical \\{104\\} faces but flat corners of

  7. Initial kinetics of the direct sulfation of limestone

    DEFF Research Database (Denmark)

    Hu, Guilin; Shang, Lei; Dam-Johansen, Kim;

    2008-01-01

    The initial kinetics of direct sulfation of Faxe Bryozo, a porous bryozoan limestone was studied in the temperature interval from 873 to 973 K in a pilot entrained flow reactor with very short reaction times (between 0.1 and 0.6 s). The initial conversion rate of the limestone - for conversions...... Faxe Bryozo. The intrinsic rate of the direct sulfation of the limestone is estimated to have an activation energy of about 25 kJ/mol and reaction orders of about 0.9 and -0.75 for SO2 and CO2, respectively. The diffusivity of carbonate ions in the surface layer of the calcite grain is estimated to be...... ions in calcite grains is established. The validity of the model is limited to the initial sulfation period, in which nucleation of the solid product calcium sulphate is not started. This theoretical reaction-diffusion model gives a good simulation of the initial kinetics of the direct sulfation of...

  8. Structural evolution of an alkali sulfate activated slag cement

    Science.gov (United States)

    Mobasher, Neda; Bernal, Susan A.; Provis, John L.

    2016-01-01

    In this study, the effect of sodium sulfate content and curing duration (from fresh paste up to 18 months) on the binder structure of sodium sulfate activated slag cements was evaluated. Isothermal calorimetry results showed an induction period spanning the first three days after mixing, followed by an acceleration-deceleration peak corresponding to the formation of bulk reaction products. Ettringite, a calcium aluminium silicate hydrate (C-A-S-H) phase, and a hydrotalcite-like Mg-Al layered double hydroxide have been identified as the main reaction products, independent of the Na2SO4 dose. No changes in the phase assemblage were detected in the samples with curing from 1 month up to 18 months, indicating a stable binder structure. The most significant changes upon curing at advanced ages observed were growth of the AFt phase and an increase in silicate chain length in the C-A-S-H, resulting in higher strength.

  9. Characterization of phosphate/sulfate waste grout cores

    Energy Technology Data Exchange (ETDEWEB)

    Martin, P.F.C.; Lokken, R.O.

    1993-09-01

    As part of efforts to clean up federal production sites, the U.S. Department of Energy (DOE) is treating selected low-level liquid wastes by incorporating them into cementitious waste forms. At the Hanford Site, low-level radioactive liquid wastes will be mixed with a blend of Portland cement, fly ash, clays, and other ingredients in a continuous process at the Grout Treatment Facility (GTF). The resulting grout slurry will be pumped to lined, underground concrete vaults where the grout will harden, thereby immobilizing contaminants. Physical property measurements and American Nuclear Society (ANS) 16.1 leach tests have been completed on 45 samples obtained from five cores from the phosphate/sulfate waste (PSW) grout vault. A summary of the compressive strength, bulk density, and sonic velocity data is compared with data from other PSW grout samples. Results of moisture content, thermal conductivity, and the leaching of aluminium, calcium, sodium, sulfate, cobalt-60, and cesium-137 are given.

  10. Development and Demonstration of a Sulfate Precipitation Process for Hanford Waste Tank 241-AN-107

    International Nuclear Information System (INIS)

    A series of precipitation experiments were conducted on Hanford waste tank 241-AN-107 samples in an effort to remove sulfate from the matrix. Calcium nitrate was added directly to AN-107 sub-samples to yield several combinations of Ca:CO3 mole ratios spanning a range of 0:1 to 3:1 to remove carbonate as insoluble CaCO3. Similarly barium nitrate was added directly to the AN-107 aliquots, or to the calcium pretreated AN-107 aliquots, giving of Ba:SO4 mole ratios spanning a range of 1:1 to 5:1 to precipitate sulfate as BaSO4. Initial bulk carbonate removal was required for successful follow-on barium sulfate precipitation. A ge 1:1 mole ratio of Ca:CO3 was found to lower the carbonate concentration such that Ba would react preferentially with the sulfate. A follow-on 1:1 mole ratio of Ba:SO4 resulted in 70% sulfate removal. The experiment was scaled up with a 735-mL aliquot of AN-107 for more complete testing. Calcium carbonate and barium sulfate settling rates were determined and fates of selected cations, anions, and radionuclides were followed through the various process steps. Seventy percent of the sulfate was removed in the scale-up test while recovering 63% of the filtrate volume. Surprisingly, during the scale-up test a sub-sample of the CaCO3/241-AN-107 slurry was found to lose fluidity upon standing for le 2 days. Metathesis with BaCO3 at ambient temperature was also evaluated using batch contacts at various BaCO3:SO4 mole ratios with no measurable success

  11. Calcium in diet

    Science.gov (United States)

    ... best source. Milk and dairy products such as yogurt, cheeses, and buttermilk contain a form of calcium ... the amount of calcium in a dairy product. Yogurt, most cheeses, and buttermilk are excellent sources of ...

  12. Fenoprofen calcium overdose

    Science.gov (United States)

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

  13. Calcium channel blocker overdose

    Science.gov (United States)

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

  14. Fenoprofen calcium overdose

    Science.gov (United States)

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

  15. Calcium and magnesium silicate hydrates

    International Nuclear Information System (INIS)

    Deep geological disposals are planed to discard long-lived intermediate-level and high-level radioactive wastes. Clay-based geological barriers are expected to limit the ingress of groundwater and to reduce the mobility of radioelements. In the interaction zone between the cement and the clay based material alteration can occur. Magnesium silicate hydrates (M-S-H) have been observed due to the reaction of magnesium sulfate containing groundwater with cements or in the interaction zone between low-pH type cement and clays. M-S-H samples synthesized in the laboratory showed that M-S-H has a variable composition within 0.7 ≤ Mg/Si ≤ 1.5. TEM/EDS analyses show an homogeneous gel with no defined structure. IR and 29Si NMR data reveal a higher polymerization degree of the silica network in M-S-H compared to calcium silicate hydrates (C-S-H). The presence of mainly Q3 silicate tetrahedrons in M-S-H indicates a sheet like or a triple-chain silica structure while C-S-H is characterised by single chain-structure. The clear difference in the silica structure and the larger ionic radius of Ca2+ (1.1 Angstrom) compared to Mg2+ (0.8 Angstrom) make the formation of an extended solid solution between M-S-H and C-S-H gel improbable. In fact, the analyses of synthetic samples containing both magnesium and calcium in various ratios indicate the formation of separate M-S-H and C-S-H gels with no or very little uptake of magnesium in CS-H or calcium in M-S-H

  16. Multistage Tandem Mass Spectrometry of Chondroitin Sulfate and Dermatan Sulfate

    OpenAIRE

    Bielik, Alicia M.; Zaia, Joseph

    2011-01-01

    Chondroitin/dermatan sulfate (CS/DS) is a glycosaminoglycan (GAG) found in abundance in extracellular matrices. In connective tissue, CS/DS proteoglycans play structural roles in maintaining viscoelasticity through the large number of immobilized sulfate groups on CS/DS chains. CS/DS chains also bind protein families including growth factors and growth factor receptors. Through such interactions, CS/DS chains play important roles in neurobiochemical processes, connective tissue homeostasis, c...

  17. Calcium and magnesium disorders.

    Science.gov (United States)

    Goff, Jesse P

    2014-07-01

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

  18. Calcium and Mitosis

    Science.gov (United States)

    Hepler, P.

    1983-01-01

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

  19. Calcium en cardioplegie

    NARCIS (Netherlands)

    Ruigrok, T.J.C.; Meijler, F.L.

    1985-01-01

    Coronary perfusion with a calcium-free solution, followed by reperfusion with a calcium containing solution, may result in acute myocardial cell death and in irreversible loss of the e1ectrical and mechanical activity of the heart. This phenomenon is known as the calcium paradox. A number of cardiop

  20. Sulfated compounds from marine organisms.

    Science.gov (United States)

    Kornprobst, J M; Sallenave, C; Barnathan, G

    1998-01-01

    More than 500 sulfated compounds have been isolated from marine organisms so far but most of them originate from two phyla only, Spongia and Echinodermata. The sulfated compounds are presented according to the phyla they have been identified from and to their chemical structures. Biological activities, when available, are also given. Macromolecules have also been included in this review but without structural details. PMID:9530808

  1. Mineral carbonation of phosphogypsum waste for production of useful carbonate and sulfate salts

    Directory of Open Access Journals (Sweden)

    Hannu-Petteri eMattila

    2015-11-01

    Full Text Available Phosphogypsum (CaSO4·2H2O waste is produced in large amounts during phosphoric acid (H3PO4 production. Minor quantities are utilized in construction or agriculture, while most of the material is stockpiled, creating an environmental challenge to prevent pollution of natural waters. In principle, the gypsum waste could be used to capture several hundred Mt of carbon dioxide (CO2. For example, when gypsum is converted to ammonium sulfate ((NH42SO4 with ammonia (NH3 and CO2, also solid calcium carbonate (CaCO3 is generated. The ammonium sulfate can be utilized as a fertilizer or in other mineral carbonation processes that use magnesium silicate-based rock as feedstock, while calcium carbonate has various uses as e.g. filler material. The reaction extent of the described process was studied by thermodynamic modeling and experimentally as a function of reactant concentrations and temperature. Other essential properties such as purity and quality of the solid products are also followed. Conversion efficiencies of >95% calcium from phosphogypsum to calcium carbonate are obtained. Scalenohedral, rhombohedral and prismatic calcite particles can be produced, though the precipitates contain certain contaminants such as rare earth metals and sulfur from the gypsum. A reverse osmosis membrane cartridge is also tested as an alternative and energy-efficient method of concentrating the ammonium sulfate salt solution instead of the traditional evaporation of the process solution.

  2. Calcium absorption and achlorhydria

    International Nuclear Information System (INIS)

    Defective absorption of calcium has been thought to exist in patients with achlorhydria. The author compared absorption of calcium in its carbonate form with that in a pH-adjusted citrate form in a group of 11 fasting patients with achlorhydria and in 9 fasting normal subjects. Fractional calcium absorption was measured by a modified double-isotope procedure with 0.25 g of calcium used as the carrier. Mean calcium absorption (+/- S.D.) in the patients with achlorhydria was 0.452 +/- 0.125 for citrate and 0.042 +/- 0.021 for carbonate (P less than 0.0001). Fractional calcium absorption in the normal subjects was 0.243 +/- 0.049 for citrate and 0.225 +/- 0.108 for carbonate (not significant). Absorption of calcium from carbonate in patients with achlorhydria was significantly lower than in the normal subjects and was lower than absorption from citrate in either group; absorption from citrate in those with achlorhydria was significantly higher than in the normal subjects, as well as higher than absorption from carbonate in either group. Administration of calcium carbonate as part of a normal breakfast resulted in completely normal absorption in the achlorhydric subjects. These results indicate that calcium absorption from carbonate is impaired in achlorhydria under fasting conditions. Since achlorhydria is common in older persons, calcium carbonate may not be the ideal dietary supplement

  3. EXERCISE ENHANCING CALCIUM ABSORPTION MECHANISM

    OpenAIRE

    Muliani

    2013-01-01

    Calcium has important role in many biological processes therefore calcium homeostasis should be maintained. Imbalance in calcium homeostasis would affects the bone metabolism, neuromuscular function, blood coagulation, cell proliferation and signal transduction. Homeostasis of calcium is maintained by three major organs: gastrointestinal tract, bone and kidney. Intestinal calcium absorption is the sole mechanism to supply calcium to the body. Calcium absorption controlled by calcitropic hormo...

  4. Bioengineered heparins and heparan sulfates.

    Science.gov (United States)

    Fu, Li; Suflita, Matthew; Linhardt, Robert J

    2016-02-01

    Heparin and heparan sulfates are closely related linear anionic polysaccharides, called glycosaminoglycans, which exhibit a number of important biological and pharmacological activities. These polysaccharides, having complex structures and polydispersity, are biosynthesized in the Golgi of animal cells. While heparan sulfate is a widely distributed membrane and extracellular glycosaminoglycan, heparin is found primarily intracellularly in the granules of mast cells. While heparin has historically received most of the scientific attention for its anticoagulant activity, interest has steadily grown in the multi-faceted role heparan sulfate plays in normal and pathophysiology. The chemical synthesis of these glycosaminoglycans is largely precluded by their structural complexity. Today, we depend on livestock animal tissues for the isolation and the annual commercial production of hundred ton quantities of heparin used in the manufacture of anticoagulant drugs and medical device coatings. The variability of animal-sourced heparin and heparan sulfates, their inherent impurities, the limited availability of source tissues, the poor control of these source materials and their manufacturing processes, suggest a need for new approaches for their production. Over the past decade there have been major efforts in the biotechnological production of these glycosaminoglycans, driven by both therapeutic applications and as probes to study their natural functions. This review focuses on the complex biology of these glycosaminoglycans in human health and disease, and the use of recombinant technology in the chemoenzymatic synthesis and metabolic engineering of heparin and heparan sulfates. PMID:26555370

  5. Tris(diisopropylammonium hydrogensulfate sulfate

    Directory of Open Access Journals (Sweden)

    Gholamhossein Sh. Mohammadnezhad

    2008-08-01

    Full Text Available The cations and anions of the title salt, 3C6H16N+·HSO4−·SO42−, are linked by N—H...O and O—H...O hydrogen bonds into a three-dimensional network. The hydrogensulfate ion, with a single S—O(H bond of 1.563 (2 Å, forms a short O—H...O hydrogen bond [O...O = 2.609 (2 Å] to the sulfate ion. The hydrogensulfate ion accepts two hydrogen bonds from two cations, whereas the sulfate ion, as an acceptor, binds to four cations. The sulfate ion is disordered approximately equally over two sites related by rotation around one of the O—S bonds.

  6. Dengue and Calcium

    OpenAIRE

    Shivanthan, Mitrakrishnan C; Rajapakse, Senaka

    2014-01-01

    Dengue is potentially fatal unless managed appropriately. No specific treatment is available and the mainstay of treatment is fluid management with careful monitoring, organ support, and correction of metabolic derangement. Evidence with regards to the role of calcium homeostasis in dengue is limited. Low blood calcium levels have been demonstrated in dengue infection and hypocalcemia maybe more pronounced in more severe forms. The cause of hypocalcemia is likely to be multifactorial. Calcium...

  7. Measurements of intracellular calcium

    International Nuclear Information System (INIS)

    Intracellular calcium concentration ([Ca2+]i) has been measured in cultured cells by using Fura-2 load cells and a computer-controlled Perkin Elmer LS-5B spectrofluorometer. Increased [Ca2+]i in cells exposed to extracellular bilirubin was observed both with and without extracellular calcium. However, the increase was considerable larger with extracellular calcium. The enhancement of [Ca2+]i became smaller with decreasing bilirubin/BSA (bovine serum albumine) ratio. 5 refs., 5 figs

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

    International Nuclear Information System (INIS)

    Calcium sulfoaluminate cements (CSA) are a promising low-CO2 alternative to ordinary Portland cements and are as well of interest concerning their use as binder for waste encapsulation. In this study, the hydration of two CSA cements has been investigated experimentally and by thermodynamic modelling between 1 h and 28 days at w/c ratios of 0.72 and 0.80, respectively. The main hydration product of CSA is ettringite, which precipitates together with amorphous Al(OH)3 until the calcium sulfate is consumed after around 1-2 days of hydration. Afterwards, monosulfate is formed. In the presence of belite, straetlingite occurs as an additional hydration product. The pore solution analysis reveals that straetlingite can bind a part of the potassium ions, which are released by the clinker minerals. The microstructure of both cements is quite dense even after 16 h of hydration, with not much pore space available at a sample age of 28 days. The pore solution of both cements is dominated during the first hours of hydration by potassium, sodium, calcium, aluminium and sulfate; the pH is around 10-11. When the calcium sulfate is depleted, the sulfate concentration drops by a factor of 10. This increases pH to around 12.5-12.8. Based on the experimental data, a thermodynamic hydration model for CSA cements based on cement composition, hydration kinetics of clinker phases and calculations of thermodynamic equilibria by geochemical speciation has been established. The modelled phase development with ongoing hydration agrees well with the experimental findings.

  9. Sulfate reduction in freshwater peatlands

    International Nuclear Information System (INIS)

    This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO42- concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 μM. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 μM h-1 while in B and C they were 1 and 0.05 μM h-1, respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 μg d-1 g-1) were found 10 cm below the water table, in B (ca. 1.0 μg d-1 g-1) in the vicinity of the water table, and in C (0.75 μg d-1 g-1) 20 cm below the water table. In all profiles both sulfate reduction and methane production rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m-2 d-1, while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m-2 d-1, respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination paper. 67 refs, 6 figs, 3 tabs

  10. Acid Sulfate Alteration on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  11. Brittlestars contain highly sulfated chondroitin sulfates/dermatan sulfates that promote fibroblast growth factor 2-induced cell signaling

    OpenAIRE

    Ramachandra, Rashmi; Namburi, Ramesh B; Ortega-Martinez, Olga; Shi, Xiaofeng; Zaia, Joseph; Dupont, Sam T.; Thorndyke, Michael C; Lindahl, Ulf; Spillmann, Dorothe

    2013-01-01

    Glycosaminoglycans (GAGs) isolated from brittlestars, Echinodermata class Ophiuroidea, were characterized, as part of attempts to understand the evolutionary development of these polysaccharides. A population of chondroitin sulfate/dermatan sulfate (CS/DS) chains with a high overall degree of sulfation and hexuronate epimerization was the major GAG found, whereas heparan sulfate (HS) was below detection level. Enzymatic digestion with different chondroitin lyases revealed exceptionally high p...

  12. Reduced Sulfation of Chondroitin Sulfate but Not Heparan Sulfate in Kidneys of Diabetic db/db Mice

    OpenAIRE

    Reine, Trine M.; Grøndahl, Frøy; Jenssen, Trond G.; Hadler-Olsen, Elin; Prydz, Kristian; Kolset, Svein O.

    2013-01-01

    Heparan sulfate proteoglycans are hypothesized to contribute to the filtration barrier in kidney glomeruli and the glycocalyx of endothelial cells. To investigate potential changes in proteoglycans in diabetic kidney, we isolated glycosaminoglycans from kidney cortex from healthy db/+ and diabetic db/db mice. Disaccharide analysis of chondroitin sulfate revealed a significant decrease in the 4-O-sulfated disaccharides (D0a4) from 65% to 40%, whereas 6-O-sulfated disaccharides (D0a6) were redu...

  13. Thermochemical sulfate reduction in deep petroleum reservoirs: a molecular approach; Thermoreduction des sulfates dans les reservoirs petroliers: approche moleculaire

    Energy Technology Data Exchange (ETDEWEB)

    Hanin, S.

    2002-11-01

    The thermochemical sulfate reduction (TSR) is a set of chemical reactions leading to hydrocarbon oxidation and production of carbon dioxide and sour gas (H{sub 2}S) which is observed in deep petroleum reservoirs enriched in anhydrites (calcium sulfate). Molecular and isotopic studies have been conducted on several crude oil samples to determine which types of compounds could have been produced during TSR. Actually, we have shown that the main molecules formed by TSR were organo-sulfur compounds. Indeed, sulfur isotopic measurements. of alkyl-di-benzothiophenes, di-aryl-disulfides and thia-diamondoids (identified by NMR or synthesis of standards) shows that they are formed during TSR as their value approach that of the sulfur of the anhydrite. Moreover, thia-diamondoids are apparently exclusively formed during this phenomenon and can thus be considered as true molecular markers of TSR. In a second part, we have investigated with laboratory experiments the formation mechanism of the molecules produced during TSR. A first model has shown that sulfur incorporation into the organic matter occurred with mineral sulfur species of low oxidation degree. The use of {sup 34}S allowed to show that the sulfates reduction occurred during these simulations. At least, some experiments on polycyclic hydrocarbons, sulfurized or not, allowed to establish that thia-diamondoids could be formed by acid-catalysed rearrangements at high temperatures in a similar way as the diamondoids. (author)

  14. Status of copper sulfate - 2008

    Science.gov (United States)

    This is brief overview of the Technical Sections completed and being worked on for the New Animal Drug Application (NADA) for copper sulfate. Initial Label Claim (Ich on catfish): 1) Human Food Safety - Complete for all fin fish – February 2004. This includes human intestinal microflora issues,...

  15. Sulfate transport in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Simonsen, K

    1988-01-01

    1. In short-circuited toad skin preparations exposed bilaterally to NaCl-Ringer's containing 1 mM SO2(-4), influx of sulfate was larger than efflux showing that the skin is capable of transporting sulfate actively in an inward direction. 2. This active transport was not abolished by substituting...... apical Na+ for K+. 3. Following voltage activation of the passive Cl- permeability of the mitochondria-rich (m.r.) cells sulfate flux-ratio increased to a value predicted from the Ussing flux-ratio equation for a monovalent anion. 4. In such skins, which were shown to exhibit vanishingly small leakage...... conductances, the variation of the rate coefficient for sulfate influx (y) was positively correlated with the rate coefficient for Cl- influx (x), y = 0.035 x - 0.0077 cm/sec (r = 0.9935, n = 15). 5. Addition of the phosphodiesterase inhibitor, 3-isobutyl-1-methyl-xanthine to the serosal bath of short...

  16. Calcium D-saccharate

    DEFF Research Database (Denmark)

    Garcia, André Castilho; Hedegaard, Martina Vavrusova; Skibsted, Leif Horsfelt

    2016-01-01

    Molar conductivity of saturated aqueous solutions of calcium d-saccharate, used as a stabilizer of beverages fortified with calcium d-gluconate, increases strongly upon dilution, indicating complex formation between calcium and d-saccharate ions, for which, at 25 °C, Kassoc = 1032 ± 80, ΔHassoc......° = -34 ± 6 kJ mol-1, and ΔSassoc° = -55 ± 9 J mol-1 K-1, were determined electrochemically. Calcium d-saccharate is sparingly soluble, with a solubility product, Ksp, of (6.17 ± 0.32) × 10-7 at 25 °C, only moderately increasing with the temperature: ΔHsol° = 48 ± 2 kJ mol-1, and ΔSassoc° = 42 ± 7 J mol-1...... K-1. Equilibria in supersaturated solutions of calcium d-saccharate seem only to adjust slowly, as seen from calcium activity measurements in calcium d-saccharate solutions made supersaturated by cooling. Solutions formed by isothermal dissolution of calcium d-gluconate in aqueous potassium d...

  17. INVESTIGATION ON PROPERTIES OF CONCRETE CONTAINING NATURAL POZZOLAN VOLCANIC ORIGIN DUE TO SULFATE ATTACK

    Directory of Open Access Journals (Sweden)

    MERIDA AHCENE

    2013-05-01

    Full Text Available Sulfate attack and its effects are important from both scientific and industrial viewpoints. It is perceived that concretes containing pozzolan have better performance in sulfate solutions, since the pozzolanic reactions reduce the quantity of calcium hydroxide and increase calcium silicate hydrate. This paper investigates thecontribution of natural pozzolan volcanic origin on the physico - mechanical and physico-chemical characteristics of the concretes. When it is coupled to a water reducing superplasticizer by a correct adjustment of the composition, it greatly improves the concrete properties. The analysis of the experimental results on pozzolan concrete at 5% content and sharpness of 9600cm2/g, in a sulphated environment, showed that it contributes positively to the improvement of its mechanical characteristics and its durability with respect towater absorption, and to the permeability to the chlorine ions as well as to the resistance to the sulphates.

  18. Serum Calcium Level in Hypertension

    OpenAIRE

    Hazari, Mohammed Abdul Hannan; Arifuddin, Mehnaaz Sameera; Muzzakar, Syed; Reddy, Vontela Devender

    2012-01-01

    Background: The alterations in extracellular calcium level may influence intracellular calcium level and possibly play a role in the pathogenesis of essential hypertension. Aim: The purpose was to find out the association between serum calcium levels and hypertension; and to compare the serum calcium levels between normotensive controls, hypertensive subjects on calcium channel blockers, and hypertensive subjects on antihypertensive medication other than calcium channel blockers. Materials an...

  19. Metabolic Flexibility of Sulfate-Reducing Bacteria

    OpenAIRE

    Plugge, Caroline M.; Zhang, Weiwen; Scholten, Johannes C. M.; Stams, Alfons J. M.

    2011-01-01

    Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas me...

  20. Sulfate reduction and methanogenesis in marine sediments

    Science.gov (United States)

    Oremland, R. S.; Taylor, B. F.

    1978-01-01

    Methanogenesis and sulfate-reduction were followed in laboratory incubations of sediments taken from tropical seagrass beds. Methanogenesis and sulfate-reduction occurred simultaneously in sediments incubated under N2, thereby indicating that the two processes are not mutually exclusive. Sediments incubated under an atmosphere of H2 developed negative pressures due to the oxidation of H2 by sulfate-respiring bacteria. H2 also stimulated methanogenesis, but methanogenic bacteria could not compete for H2 with the sulfate-respiring bacteria.

  1. Calcium-phospholipid enhanced protein phosphorylation in human placenta

    International Nuclear Information System (INIS)

    Calcium-activated, phospholipid-dependent protein phosphorylation has not been studied in placenta. Human placental cytosol was subjected to an endogenous protein phosphorylation assay using [γ-32P]ATP in the presence of calcium and phosphatidylserine. Protein phosphorylation was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. When compared to basal levels, calcium (10-6 M) in combination with phosphatidylserine (50 μg/ml) significantly enhanced (P 32P incorporation into phosphoproteins having mol wt 47,000, 43,000, and 37,000. Half-maximal 22P incorporation was observed with 3.5 x 10-7 M Ca2+ in the presence of phosphatidylserine (50 μg/ml). The effect of phosphatidylserine was biphasic. In the presence of Ca 10-6 M, 32P incorporation increased to a maximum at 70 +g/ml of phosphatidylserine. The increase was suppressed at 150 μg/ml. Tetracaine caused a dose-dependent inhibition of calcium-activated, phospholipid-dependent enhancement of the three phosphoproteins. Calcium in the absence of phospholipid enhanced the phosphorylation of a protein of 98,000 mol wt. Phosphatidylserine suppressed this enhancement. Calmodulin (10-6 M) had no detectable effect upon phosphorylation beyond that of calcium alone, but the calmodulin inhibitor R-24571 specifically inhibited the calcium-stimulated 98,000 mol wt phosphoprotein. Calcium-activated, phospholipid-dependent phospholipid-dependent phosphoproteins are present in human placental cytosol; whether calcium-activated, calmodulin-dependent phosphoproteins also are present remains a question

  2. 21 CFR 182.1125 - Aluminum sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  3. 21 CFR 582.1125 - Aluminum sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  4. 21 CFR 186.1797 - Sodium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium sulfate. 186.1797 Section 186.1797 Food and... Substances Affirmed as GRAS § 186.1797 Sodium sulfate. (a) Sodium sulfate (Na2SO4, CAS Reg. No. 7757-82-6... crystalline powder. It is prepared by the neutralization of sulfuric acid with sodium hydroxide. (b)...

  5. Sulfate-reducing prokaryotes in river floodplains

    NARCIS (Netherlands)

    Miletto, M.

    2007-01-01

    This thesis constitutes a pioneer attempt at elucidating the ecology of sulfate-reducing prokaryotes in river floodplains. These are non-typical sulfate-reducing environmental settings, given the generally low sulfate concentration that characterize freshwater habitats, and river flow regulation tha

  6. 21 CFR 582.5461 - Manganese sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese sulfate. 582.5461 Section 582.5461 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5461 Manganese sulfate. (a) Product. Manganese sulfate. (b) Conditions of use....

  7. 21 CFR 184.1461 - Manganese sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS... manganese compounds with sulfuric acid. It is also obtained as a byproduct in the manufacture...

  8. 21 CFR 184.1443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  9. 21 CFR 582.5443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium sulfate. 582.5443 Section 582.5443 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5443 Magnesium sulfate. (a) Product. Magnesium sulfate. (b) Conditions of use....

  10. Effect of vitamin D supplementation and magnesium sulfate therapy in pre-eclampsia

    OpenAIRE

    Neeru Bhaskar; Harnam Kaur; Sheikh Ishaq; Ruhi Mahajan; Qazi Najeeb

    2014-01-01

    Background: Vitamin D insufficiency has been associated with several adverse health outcomes, including pregnancy outcomes, and is increasingly recognised as a public health concern. It is responsible for approximately 50,000 maternal deaths yearly worldwide, 25% of all cases of fetal growth restriction, and 15% of preterm births in developed countries. Objective: Vitamin D and magnesium sulfate act by altering the calcium levels so this study was conducted to see if vitamin D supplementation...

  11. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free calciu

  12. Hydration of Portland cement with additions of calcium sulfoaluminates

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-15

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

  13. Hydration of Portland cement with additions of calcium sulfoaluminates

    International Nuclear Information System (INIS)

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

  14. Impact of mitigation strategies on acid sulfate soil chemistry and microbial community.

    Science.gov (United States)

    Wu, Xiaofen; Sten, Pekka; Engblom, Sten; Nowak, Pawel; Österholm, Peter; Dopson, Mark

    2015-09-01

    Potential acid sulfate soils contain reduced iron sulfides that if oxidized, can cause significant environmental damage by releasing large amounts of acid and metals. This study examines metal and acid release as well as the microbial community capable of catalyzing metal sulfide oxidation after treating acid sulfate soil with calcium carbonate (CaCO3) or calcium hydroxide (Ca(OH)2). Leaching tests of acid sulfate soil samples were carried out in the laboratory. The pH of the leachate during the initial flushing with water lay between 3.8 and 4.4 suggesting that the jarosite/schwertmannite equilibrium controls the solution chemistry. However, the pH increased to circa 6 after treatment with CaCO3 suspension and circa 12 after introducing Ca(OH)2 solution. 16S rRNA gene sequences amplified from community DNA extracted from the untreated and both CaCO3 and Ca(OH)2 treated acid sulfate soils were most similar to bacteria (69.1% to 85.7%) and archaea (95.4% to 100%) previously identified from acid and metal contaminated environments. These species included a Thiomonas cuprina-like and an Acidocella-like bacteria as well as a Ferroplasma acidiphilum-like archeon. Although the CaCO3 and Ca(OH)2 treatments did not decrease the proportion of microorganisms capable of accelerating acid and metal release, the chemical effects of the treatments suggested their reduced activity. PMID:25933291

  15. [Study on the Influence of Mineralizer on the Preparation of Calcium Aluminates Based on Infrared Spectroscopy].

    Science.gov (United States)

    Fan, Wei; Wang, Liang; Zheng, Huai-li; Chen, Wei; Tang, Xiao-min; Shang, Juan-fang; Qian, Li

    2015-05-01

    In this study, effect of mineralizer on the structure and spectraproperties of calcium aluminates formation was extensively studied. Medium or low-grade bauxite and calcium carbonate were used as raw material and mineralizer CaF2 as additive. Calcium aluminates can be obtained after mixing fully, calcination and grinding. The prepared calcium aluminates can be directly used for the production of polyaluminiumchloride (PAC), polymeric aluminum sulfate, sodium aluminate and some other water treatment agents. The calcium aluminates preparation technology was optimized by investigating the mass ratio of raw materials (bauxiteand calcium carbonate) and mineralizer CaF2 dosage. The structure and spectra properties of bauxite and calcium aluminates were characterized by Fourier transform infrared(FTIR) spectroscopy analysis and the mineralization mechanism of the mineralizer was studied. FTIR spectra indicated that the addition of mineralizer promoted the decomposition and transformation of the diaspore, gibbsite and kaolinite, the decomposition of calcium carbonate, and more adequately reaction between bauxite and calcium carbonate. In addition, not only Ca in calcium carbonate and Si in bauxite were more readily reacted, but also Si-O, Si-O-Al and Al-Si bonds in the bauxite were more fractured which contributed to the release of Al in bauxite, and therefore, the dissolution rate of Al2O3 could be improved. The dissolution rate of Al2O3 can be promoted effectively when the mineralizer CaF2 was added in a mass ratio amount of 3%. And the mineralizer CaF2 cannot be fully functioned, when its dosage was in a mass percent of 1. 5%. Low-grade bauxite was easier to sinter for the preparation of calcium aluminates comparing with the highgrade one. The optimum material ratio for the preparation of calcium aluminates calcium at 1 250 °C was the mass ratio between bauxite and calcium carbonate of 1 : 0. 6 and mineralizer CaF2 mass ratio percent of 3%. PMID:26415430

  16. Sulfates on Mars: Indicators of Aqueous Processes

    Science.gov (United States)

    Bishop, Janice L.; Lane, Melissa D.; Dyar, M. Darby; Brown, Adrian J.

    2006-01-01

    Recent analyses by MER instruments at Meridiani Planum and Gusev crater and the OMEGA instrument on Mars Express have provided detailed information about the presence of sulfates on Mars [1,2,3]. We are evaluating these recent data in an integrated multi-disciplinary study of visible-near-infrared, mid-IR and Mossbauer spectra of several sulfate minerals and sulfate-rich analog sites. Our analyses suggest that hydrated iron sulfates may account for features observed in Mossbauer and mid-IR spectra of Martian soils [4]. The sulfate minerals kieserite, gypsum and other hydrated sulfates have been identified in OMEGA spectra in the layered terrains in Valles Marineris and Terra Meridiani [2]. These recent discoveries emphasize the importance of studying sulfate minerals as tracers of aqueous processes. The sulfate-rich rock outcrops observed in Meridiani Planum may have formed in an acidic environment similar to acid rock drainage environments on Earth [5]. Because microorganisms typically are involved in the oxidation of sulfides to sulfates in terrestrial sites, sulfate-rich rock outcrops on Mars may be a good location to search for evidence of past life on that planet. Whether or not life evolved on Mars, following the trail of sulfate minerals will lead to a better understanding of aqueous processes and chemical weathering.

  17. Manufacture of ammonium sulfate fertilizer from gypsum-rich byproduct of flue gas desulfurization - A prefeasibility cost estimate

    Science.gov (United States)

    Chou, I.-Ming; Rostam-Abadi, M.; Lytle, J.M.; Achorn, F.P.

    1996-01-01

    Costs for constructing and operating a conceptual plant based on a proposed process that converts flue gas desulfurization (FGD)-gypsum to ammonium sulfate fertilizer has been calculated and used to estimate a market price for the product. The average market price of granular ammonium sulfate ($138/ton) exceeds the rough estimated cost of ammonium sulfate from the proposed process ($111/ ton), by 25 percent, if granular size ammonium sulfate crystals of 1.2 to 3.3 millimeters in diameters can be produced by the proposed process. However, there was at least ??30% margin in the cost estimate calculations. The additional costs for compaction, if needed to create granules of the required size, would make the process uneconomical unless considerable efficiency gains are achieved to balance the additional costs. This study suggests the need both to refine the crystallization process and to find potential markets for the calcium carbonate produced by the process.

  18. Neuronal calcium sparks and intracellular calcium “noise”

    OpenAIRE

    Melamed-Book, Naomi; Kachalsky, Sylvia G.; Kaiserman, Igor; Rahamimoff, Rami

    1999-01-01

    Intracellular calcium ions are involved in many forms of cellular function. To accommodate so many control functions, a complex spatiotemporal organization of calcium signaling has developed. In both excitable and nonexcitable cells, calcium signaling was found to fluctuate. Sudden localized increases in the intracellular calcium concentration—or calcium sparks—were found in heart, striated and smooth muscle, Xenopus Laevis oocytes, and HeLa and P12 cells. In the nervous system, intracellular...

  19. Characterisation of Ba(OH)(2)-Na2SO4-blast furnace slag cement-like composites for the immobilisation of sulfate bearing nuclear wastes

    OpenAIRE

    Mobasher, N.; Bernal, S. A.; Hussain, O.H.; Apperley, D.C.; Kinoshita, H.; Provis, J.L.

    2014-01-01

    Soluble sulfate ions in nuclear waste can have detrimental effects on cementitious wasteforms and disposal facilities based on Portland cement. As an alternative, Ba(OH)2–Na2SO4–blast furnace slag composites are studied for immobilisation of sulfate-bearing nuclear wastes. Calcium aluminosilicate hydrate (C–A–S–H) with some barium substitution is the main binder phase, with barium also present in the low solubility salts BaSO4 and BaCO3, along with Ba-substituted calcium sulfoaluminate hydrat...

  20. Adsorption of Potassium and Calcium Ions by Variable Charge Soils

    Institute of Scientific and Technical Information of China (English)

    LIHONG-YAN; JIGUO-LIANG

    1992-01-01

    Interactions of potassium and calcium ions with four typical variable charge soils in South China were examined by measuring pK-0.5pCa value with a potassium ion-selective electrode and a calcium ion-selective electrode,and pK value with a potassium ion-selective electrode.The results showed that adsorption of potassium and calcium ions increased with soil suspension pH,and the tendency of the pK-0.5pCa value changing with pH differed with respect to pH range and potassium to calcium ratio.Adsorption of equal amount of calcium and potassium ions led to release of an identical number of protons,suggesting similar adsorption characteristics of these two ions when adsorbed by variable charge soils.Compared with red soil,latosol and lateritic red soil had higher adsorption selectivities for calcium ion.The red soil had a greater affinity for potassium ion than that for calcium ion at low concentration,which seems to result from its possession of 2:1 type minerals,such as vermiculite and mica with a high affinity for potassium ion.The results indicated that adsorption of potassium and calcium ions by the variable charge soils was chiefly caused by the electrostatic attraction between the cations and the soil surfaces.Moreover,it was found that sulfate could affect the adsorption by changing soil surface properties and by forming ion-pair.

  1. Bone healing response to an injectable calcium phosphate cement with enhanced radiopacity.

    Science.gov (United States)

    Acarturk, Oguz; Lehmicke, Michael; Aberman, Harold; Toms, Derek; Hollinger, Jeffrey O; Fulmer, Mark

    2008-07-01

    The aim of this study was to determine the impact of barium sulfate on remodeling and regeneration in standard tibial defects in rabbits treated with the Norian skeletal repair system (SRS). Two formulations of SRS (with and without barium sulfate) were injected into the medullary canal of the tibia of New Zealand white rabbits. Animals were sacrificed at 6 weeks, 6 months, 1 year, and 2 years. Over the 2-year duration of the study, standard SRS and SRS with barium sulfate appeared to be biocompatible and osteoconductive with no evidence of either inflammation or fibrous tissue around the implant materials or at the bone-material interfaces. This outcome underscores the osteophilic property of the SRS. A difference we observed between the standard SRS and the SRS with barium sulfate was the appearance of acellular material contiguous to the SRS with barium sulfate. Energy dispersive X-ray spectroscopy (EDX) analysis was conducted and confirmed that the acellular material was barium sulfate. Pathological examination of additional tissues including regional lymph nodes revealed neither dissemination of calcium phosphate nor barium sulfate. We concluded that the residual barium sulfate detected by EDX was localized to the intramedullary canal of the tibia. PMID:18098201

  2. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk;

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...... calcium binds silicon primarily as calcium silicates and less as potassium calcium silicates....

  3. Comportement des materiaux cimentaires: Actions des sulfates et de la temperature

    Science.gov (United States)

    Barbarulo, Remi

    The research work presented in this Ph.D. thesis is related to the nuclear waste underground repository concept. Concrete could be used in such a repository, and would be subjected to variations of temperature in presence of sulfate, a situation that could induce expansion of concrete. The research was lead in three parts: an experimental study of the possibility of an internal sulfate attack on mortars; an experimental study and modeling of the chemical equilibriums of the CaO-SiO2-Al2O 3-SO-H2O system; and a modeling of the mechanisms of internal and external sulfate attacks, and the effect of temperature. The results show that mortars can develop expansions after a steam-cure during hydration, but also when a long steam-cure is applied to one-year-old mortars, which is a new point. Ettringite precipitation can be considered as responsible for these expansions. The experimental study of the CaO-SiO2-Al2O 3-SO3-H2O system clarified the role of Calcium Silicate Hydrates (C-S-H) on chemical equilibriums of cementitious materials. Sulfate sorption on C-S-H has been studied in detail. The quantity of sulfate bound to the C-S-H mainly depends on the sulfate concentration in solution, on the Ca/Si ratio of the C-S-H and is not significantly influenced by temperature. Aluminium inclusion in the C-S-H seems to be a significant phenomenon. Temperature increases the calcium sulfoaluminate solubilities and thus increases sulfates concentration in solution. A modeling of the chemical system is proposed. Simulations of external sulfate attack (15 mmol/L of Na2SO 4) predict ettringite precipitation at 20 and 85°C. Simulation of internal sulfate attack was performed at a local scale (a hydrated cement grain). An initial inhomogeneity can lead, after a thermal curing at 85°C, to ettringite precipitation in zones originally free from ettringite. This new-formed ettringite could be the origin of the expansions.

  4. Heparin cofactor II is degraded by heparan sulfate and dextran sulfate.

    Science.gov (United States)

    Saito, Akio

    2015-02-20

    Heparan sulfate normally binds to heparin cofactor II and modulates the coagulation pathway by inhibiting thrombin. However, when human heparin cofactor II was incubated with heparan sulfate, heparin cofactor II became degraded. Other glycosaminoglycans were tested, including hyaluronic acid, chondroitin sulfates, dermatan sulfate, and heparin, but only dextran sulfate also degraded heparin cofactor II. Pretreatment of heparan sulfate with heparinase reduced its heparin cofactor II-degrading activity. Heparan sulfate and dextran sulfate diminished the thrombin inhibitory activity of heparin cofactor II. Other serpins, including antithrombin III and pigment epithelium-derived factor, were also degraded by heparan sulfate. This is the first evidence of acidic polysaccharides exhibiting protein-degrading activity without the aid of other proteins. PMID:25600805

  5. Modeling of ferric sulfate decomposition and sulfation of potassium chloride during grate‐firing of biomass

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Jappe Frandsen, Flemming;

    2013-01-01

    Ferric sulfate is used as an additive in biomass combustion to convert the released potassium chloride to the less harmful potassium sulfate. The decomposition of ferric sulfate is studied in a fast heating rate thermogravimetric analyzer and a volumetric reaction model is proposed to describe the...... process. The yields of sulfur oxides from ferric sulfate decomposition under boiler conditions are investigated experimentally, revealing a distribution of approximately 40% SO3 and 60% SO2. The ferric sulfate decomposition model is combined with a detailed kinetic model of gas‐phase KCl sulfation and a...... model of K2SO4 condensation to simulate the sulfation of KCl by ferric sulfate addition. The simulation results show good agreements with experiments conducted in a biomass grate‐firing reactor. The results indicate that the SO3 released from ferric sulfate decomposition is the main contributor to KCl...

  6. Calcium binding by dietary fibre

    International Nuclear Information System (INIS)

    Dietary fibre from plants low in phytate bound calcium in proportion to its uronic-acid content. This binding by the non-cellulosic fraction of fibre reduces the availability of calcium for small-intestinal absorption, but the colonic microbial digestion of uronic acids liberates the calcium. Thus the ability to maintain calcium balance on high-fibre diets may depend on the adaptive capacity on the colon for calcium. (author)

  7. [Calcium suppletion for patients who use gastric acid inhibitors: calcium citrate or calcium carbonate?].

    NARCIS (Netherlands)

    Jonge, H.J. de; Gans, R.O.; Huls, G.A.

    2012-01-01

    Various calcium supplements are available for patients who have an indication for calcium suppletion. American guidelines and UpToDate recommend prescribing calcium citrate to patients who use antacids The rationale for this advice is that water-insoluble calcium carbonate needs acid for adequate ab

  8. Similarities Across Mars: Acidic Fluids at Both Meridiani Planum and Gale Crater in the Formation of Magnesium-Nickel Sulfates

    Science.gov (United States)

    Yen, Albert S.; Ming, Douglas W.; Gellert, Ralf; Mittlefehldt, David W.; Vaniman, David T.; Thompson, Lucy M.; Morris, Richard V.; Clark, Benton C.; Arvidson, Raymond

    2016-01-01

    In-situ identification of sulfates at the martian surface by the Mars Exploration Rovers and the Mars Science Laboratory have included calcium sulfates with various states of hydration (gypsum, bassanite, anhydrite), iron sulfates of likely fumarolic origin, massive deposits of iron hydroxysulfates indicative of an acidic history, and minor occurrences of magnesium sulfates. Recent measurements by the Opportunity and Curiosity Alpha Particle X-ray Spectrometers (APXS) have indicated the presence of Ni-substituted Mg-sulfates at the Meridiani Planum and Gale Crater landing sites. The Opportunity rover has traversed nearly 43 km and is currently exploring the impact breccias of the rim of Endeavour crater, near a location where signatures of aqueous alteration have been established from orbit. APXS analyses of subsurface materials excavated by a rover wheel show clear evidence for a Mg(Ni)-sulfate with Mg:Ni (is) approximately 100:1 (molar). On the other side of the planet, Curiosity is continuing its climb up Mount Sharp after driving (is) approximately 13 km since landing. Over the last 4 km of the traverse, there have been multiple chemical analyses of erosionally-resistant nodules and dendritic features in a finely laminated mudstone unit which also indicate Mg(Ni)-sulfate (Mg:Ni (is) approximately 30:1, molar). The geologic settings for the Endeavour rim and the Mount Sharp mudstones are clearly different, but similar formation conditions for these sulfates may be possible. Ni(2+) readily substitutes for Mg(2+) in a variety of geochemical processes due to their comparable ionic radii. The availability of soluble Ni at the time of Mg-sulfate precipitation suggests acidic solutions. The fluids responsible for alteration in the Endeavour rim and for the formation of nodules in Gale mudstones may have had similar chemical characteristics at the time the Mg-sulfates were formed.

  9. Antibodies against the calcium-binding protein

    International Nuclear Information System (INIS)

    Plant microsomes contain a protein clearly related to a calcium-binding protein, calsequestrin, originally found in the sarcoplasmic reticulum of muscle cells, responsible for the rapid release and uptake of Ca2+ within the cells. The location and role of calsequestrin in plant cells is unknown. To generate monoclonal antibodies specific to plant calsequestrin, mice were immunized with a microsomal fraction from cultured cells of Streptanthus tortuosus (Brassicaceae). Two clones cross-reacted with one protein band with a molecular weight equal to that of calsequestrin (57 kilodaltons) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. This band is able to bind 45Ca2+ and can be recognized by a polyclonal antibody against the canine cardiac muscle calsequestrin. Rabbit skeletal muscle calsequestrin cross-reacted with the plant monoclonal antibodies. The plant monoclonal antibodies generated here are specific to calsequestrin protein

  10. Calcium in plant cells

    Directory of Open Access Journals (Sweden)

    V. V. Schwartau

    2014-04-01

    Full Text Available The paper gives the review on the role of calcium in many physiological processes of plant organisms, including growth and development, protection from pathogenic influences, response to changing environmental factors, and many other aspects of plant physiology. Initial intake of calcium ions is carried out by Ca2+-channels of plasma membrane and they are further transported by the xylem owing to auxins’ attractive ability. The level of intake and selectivity of calcium transport to ove-ground parts of the plant is controlled by a symplast. Ca2+enters to the cytoplasm of endoderm cells through calcium channels on the cortical side of Kaspary bands, and is redistributed inside the stele by the symplast, with the use of Ca2+-АТPases and Ca2+/Н+-antiports. Owing to regulated expression and activity of these calcium transporters, calclum can be selectively delivered to the xylem. Important role in supporting calcium homeostasis is given to the vacuole which is the largest depo of calcium. Regulated quantity of calcium movement through the tonoplast is provided by a number of potential-, ligand-gated active transporters and channels, like Ca2+-ATPase and Ca2+/H+ exchanger. They are actively involved in the inactivation of the calcium signal by pumping Ca2+ to the depo of cells. Calcium ATPases are high affinity pumps that efficiently transfer calcium ions against the concentration gradient in their presence in the solution in nanomolar concentrations. Calcium exchangers are low affinity, high capacity Ca2+ transporters that are effectively transporting calcium after raising its concentration in the cell cytosol through the use of protons gradients. Maintaining constant concentration and participation in the response to stimuli of different types also involves EPR, plastids, mitochondria, and cell wall. Calcium binding proteins contain several conserved sequences that provide sensitivity to changes in the concentration of Ca2+ and when you

  11. Physico-chemical properties and toxic effect of fruit-ripening agent calcium carbide

    Directory of Open Access Journals (Sweden)

    Mohammad Asif

    2012-01-01

    Full Text Available Ripening is the final stage of the maturation process, when the fruit changes color, softens and develops the flavor, texture and aroma that constitute optimum eating quality. This study was conducted to discuss the use of unsatisfactory calcium carbide to ripen fruits for domestic markets as well as their toxic effects on human health. The commonly used ripening agents are calcium carbide, acetylene, ethylene, propylene, ethrel (2-chloroethyl phosphonic acid, glycol, ethanol and some other agents. The calcium carbide is one of the most commonly used ripening agent for fruits, while other calcium salts like calcium ammonium nitrate, calcium chloride and calcium sulfate are used to delay fruit ripening agents for local fruit industries. The use of calcium carbide is being discouraged worldwide, due to associated health hazards. Calcium carbide treatment of food is extremely hazardous because it contains traces of arsenic and phosphorous, and once dissolved in water, it produces acetylene gas. Arsenic, phosphorous and acetylene gas may affect the different body organs and causes various health problems like headache, dizziness, mood disturbances, sleepiness, mental confusion, memory loss, cerebral edema, seizures and prolonged hypoxia.

  12. The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

    2010-04-15

    The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

  13. Sulfated Tyrosines Contribute to the Formation of the C5a Docking Site of the Human C5a Anaphylatoxin Receptor

    Science.gov (United States)

    Farzan, Michael; Schnitzler, Christine E.; Vasilieva, Natalya; Leung, Doris; Kuhn, Jens; Gerard, Craig; Gerard, Norma P.; Choe, Hyeryun

    2001-01-01

    The complement anaphylatoxin C5a and its seven-transmembrane segment (7TMS) receptor play an important role in host defense and in a number of inflammation-associated pathologies. The NH2-terminal domain of the C5a receptor (C5aR/CD88) contributes substantially to its ability to bind C5a. Here we show that the tyrosines at positions 11 and 14 of the C5aR are posttranslationally modified by the addition of sulfate groups. The sulfate moieties of each of these tyrosines are critical to the ability of the C5aR to bind C5a and to mobilize calcium. A C5aR variant lacking these sulfate moieties efficiently mobilized calcium in response to a small peptide agonist, but not to C5a, consistent with a two-site model of ligand association in which the tyrosine-sulfated region of the C5aR mediates the initial docking interaction. A peptide based on the NH2 terminus of the C5aR and sulfated at these two tyrosines, but not its unsulfated analogue or a doubly sulfated control peptide, partially inhibited C5a association with its receptor. These observations clarify structural and mutagenic studies of the C5a/C5aR association and suggest that related 7TMS receptors are also modified by functionally important sulfate groups on their NH2-terminal tyrosines. PMID:11342590

  14. Evaluating Deterioration of Concrete by Sulfate Attack

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Effects of factors such as water to cement ratio, fly ash and silica fume on the resistance of concrete to sulfate attack were investigated by dry-wet cycles and immersion method. The index of the resistance to sulfate attack was used to evaluate the deterioration degree of concrete damaged by sulfate. The relationship between the resistance of concrete to sulfate attack and its permeability/porosity were analyzed as well as its responding mechanism. Results show that the depth of sulfate crystal attack from surface to inner of concrete can be reduced by decreasing w/c and addition of combining fly ash with silica fume. The variation of relative elastic modulus ratio and relative flexural strength ratio of various specimens before and after being subjected to sulfate attack was compared.

  15. Chondroitin Sulfate Perlecan Enhances Collagen Fibril Formation

    DEFF Research Database (Denmark)

    Kvist, A. J.; Johnson, A. E.; Mörgelin, M.;

    2006-01-01

    disaccharides typical for chondroitin sulfate E. Indeed, purified glycosaminoglycans from perlecan-enriched fractions of cartilage extracts contain elevated levels of 4,6-disulfated chondroitin sulfate disaccharides and enhance collagen fibril formation. The effect on collagen assembly is proportional to the...... content of the 4,6-disulfated disaccharide in the different cartilage extracts, with growth plate cartilage glycosaminoglycan being the most efficient enhancer. These findings demonstrate a role for perlecan chondroitin sulfate side chains in cartilage extracellular matrix assembly and provide an...... collagen type II fibril assembly by perlecan-null chondrocytes. Cartilage perlecan is a heparin sulfate or a mixed heparan sulfate/chondroitin sulfate proteoglycan. The latter form binds collagen and accelerates fibril formation in vitro, with more defined fibril morphology and increased fibril diameters...

  16. Effect of Calcium Oxide Additive on the Performance of Iron Oxide Sorbent for High-Temperature Coal Gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    Huiling Fan; Kechang Xie; Ju Shangguan; Fang Shen; Chunhu Li

    2007-01-01

    The effect of calcium oxide additive in iron oxide sorbent for hot gas desulfurization was investigated by XRD and TPR techniques. XRD characterization showed that CaO was highly dispersed after the calcination of sorbents. Calcium sulfate formed in the desulfurization was decomposed and regenerated to CaO by reacting with CO before the next sulfidation process. Calcium participated in every sulfidation/regeneration cycle and contributed to the enhancement of sulfur capacity. The TPR results showed that the reduction temperature of the sorbent increased with the increase of the content of calcium. Calcium played a role of retarding reduction. Therefore, the addition of calcium oxide additive will benefit the utilization of iron oxide sorbent in strongly reducing atmospheres.

  17. Sulfate-reducing bacteria in anaerobic bioreactors.

    OpenAIRE

    Oude Elferink, S.J.W.H.

    1998-01-01

    The treatment of industrial wastewaters containing high amounts of easily degradable organic compounds in anaerobic bioreactors is a well-established process. Similarly, wastewaters which in addition to organic compounds also contain sulfate can be treated in this way. For a long time, the occurrence of sulfate reduction was considered to be undesired. However, there are some recent developments in which sulfate reduction is optimized for the removal of sulfur compounds from waste streams. In...

  18. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    OpenAIRE

    Chuxia Lin

    2012-01-01

    Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs), which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coas...

  19. Methods for sulfate air quality management

    OpenAIRE

    Cass, Glen R.; McMurry, Pamela S.; Houseworth, James E

    1980-01-01

    Executive Summary Abstract: A study of methods for sulfate air quality control strategy design has been conducted. Analytical tools developed were tested within a case study of the nature and causes of the high sulfate concentrations observed in the Los Angeles area. A principal objective was to investigate the least costly means for sulfate air quality improvement in that locale. A long-run average emissions to air quality model was derived which computes pollutant concentrations fr...

  20. Effect of chemical mixing state on the hygroscopicity and cloud nucleation properties of calcium mineral dust particles

    Directory of Open Access Journals (Sweden)

    R. C. Sullivan

    2009-01-01

    Full Text Available Atmospheric mineral dust particles can alter cloud properties and thus climate by acting as cloud condensation nuclei (CCN that form cloud droplets. The CCN activation properties of various calcium mineral dust particles were studied experimentally to investigate the consequences of field observations showing the segregation of sulfate from nitrate and chloride between individual aged Asian dust particles, and the enrichment of oxalic acid in Asian dust. Each mineral's observed apparent hygroscopicity was primarily controlled by its solubility, which determines the degree to which the mineral's intrinsic hygroscopicity can be expressed. The significant increase in hygroscopicity caused by mixing soluble hygroscopic material with insoluble mineral particles is also presented. Insoluble minerals including calcium carbonate, representing fresh unprocessed dust, and calcium sulfate, representing atmospherically processed dust, had similarly small apparent hygroscopicities. Their activation is accurately described by a deliquescence limit following the Kelvin effect and corresponded to an apparent single-hygroscopicity parameter, κ, of ~0.001. Soluble calcium chloride and calcium nitrate, representing atmospherically processed mineral dust particles, were much more hygroscopic, activating similar to ammonium sulfate with κ~0.5. Calcium oxalate monohydrate (κ=0.05 was significantly less CCN-active than oxalic acid (κ=0.3, but not as inactive as its low solubility would predict. These results indicate that the common assumption that all mineral dust particles become more hygroscopic and CCN-active after atmospheric processing should be revisited. Calcium sulfate and calcium oxalate are two realistic proxies for aged mineral dust that remain non-hygroscopic. The dust's apparent hygroscopicity will be controlled by its chemical mixing state, which is determined by its mineralogy and the chemical reaction pathways it experiences during

  1. Gravimetric Determination of Calcium as Calcium Carbonate Hydrate.

    Science.gov (United States)

    Henrickson, Charles H.; Robinson, Paul R.

    1979-01-01

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

  2. Expanding the 3-O-Sulfate Proteome-Enhanced Binding of Neuropilin-1 to 3-O-Sulfated Heparan Sulfate Modulates Its Activity.

    Science.gov (United States)

    Thacker, Bryan E; Seamen, Emylie; Lawrence, Roger; Parker, Matthew W; Xu, Yongmei; Liu, Jian; Vander Kooi, Craig W; Esko, Jeffrey D

    2016-04-15

    Binding of proteins to heparan sulfate is driven predominantly by electrostatic interactions between positively charged amino acid residues in the protein and negatively charged sulfate groups located at various positions along the polysaccharide chain. Although many heparin/heparan-sulfate-binding proteins have been described, few exhibit preferential binding for heparan sulfates containing relatively rare 3-O-sulfated glucosamine residues. To expand the "3-O-sulfate proteome," affinity matrices were created from Chinese hamster ovary (CHO) cell heparan sulfate engineered in vitro with and without 3-O-sulfate groups. Fractionation of different animal sera yielded several proteins that bound specifically to columns containing 3-O-sulfated heparan sulfate modified by two members of the heparan sulfate 3-O-sulfotransferase superfamily, Hs3st1 and Hs3st2. Neuropilin-1 was analyzed in detail because it has been implicated in angiogenesis and axon guidance. We show that 3-O-sulfation enhanced the binding of neuropilin-1 to heparan sulfate immobilized on plastic plates and to heparan sulfate present on cultured cells. Chemoenzymatically synthesized 3-O-sulfated heparan sulfate dodecamers protected neuropilin-1 from thermal denaturation and inhibited neuropilin-1-dependent, semaphorin-3a-induced growth cone collapse of neurons derived from murine dorsal root ganglia. The effect of 3-O-sulfation was cell autonomous and specific to Hs3st2 based on collapse assays of neurons derived from Hs3st1- and Hs3st2-deficient mice. Finally, 3-O-sulfated heparan sulfate enhanced the inhibition of endothelial cell sprouting by exogenous heparan sulfate. These findings demonstrate a reliable method to identify members of the 3-O-sulfate proteome and that 3-O-sulfation of heparan sulfate can modulate axonal growth cone collapse and endothelial cell sprouting. PMID:26731579

  3. CALCIUM SOAP LUBRICANTS

    OpenAIRE

    Alaz, Izer; Tugce, Nefise; Devrim, Balköse

    2014-01-01

    The article studies the properties of calcium stearate (CaSt2) and lubricants produced on its basis. These lubricants were prepared using sodium stearate and calcium chloride by subsidence from aqueous solutions. The CaSt2 and the light fraction of crude oil were mixed together to obtain lubricating substances. The article shows that CaSt2 had the melting temperature of 142.8 C that is higher than the melting temperature of crude oil (128 C). The compositions of obtained lubricants were stu...

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

    Science.gov (United States)

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

  5. Spatial Distribution of Sulfate and the Formation of Ettringite in Lime-Amended Soils of Central Texas

    Science.gov (United States)

    Kuo, L.; Markley, C. T.; Herbert, B. E.; Little, D. N.

    2004-12-01

    During road construction, the use of calcium-based stabilizers, such as calcium oxide (lime), in sulfate-bearing clay soils has historically lead to distress and heave due to the formation of ettringite and possibly thaumasite. Ettringite (Ca6(Al(OH)6)2(SO4)3*26H2O) is a hydrous calcium alumino-sulfate mineral that precipitates in environments with high pH and high sulfate activity. Field surveys of soil conductivity quantified using electromagnetics (EM31), geochemical characterization of soils, geochemical modeling of ettringite precipitation in lime-amended soils, and landscape characterization using existing geospatial databases were coupled to prediction the potential for ettringite formation along the SH 130 corridor, a new toll road being constructed in central Texas. Electromagnetic surveys of soil conductivities were conducted at two sites near HWY 290 and HWY 79, in the SH 130 corridor. Soil conductivities at the two sites were correlated extractable SO42- and other soil properties (extractable Al, Ca, and Mg) quantified by water extracts at two pHs (pH 8-9 and 12). At the HWY 290 site, the soil conductivity ranged from 111 to 184 ms/m, while the conductivity ranged from 34-48 ms/m at the HWY 79 site. The concentration of extractable SO42- in HWY 290 and HWY 79 sites are up to 7269 mg/kg and 406 mg/kg, respectively. Soils at these sites are dominated by smectitic clay with relatively high amounts of carbonate. Information from STATSGO, the USDA soil database, and the comparisons between the results of the field surveys and laboratory soil analyses show that variations in sulfate levels at the two sites are strongly influenced by topography. The HWY 79 site is fairly level and there are only very weak trends in the sulfate composition of the soils. The HWY 290 site, on the other hand, is fairly hilly, with a dry stream channel, whose soil and sediments exhibited very high sulfate concentrations. The strong topographic slope influences hydrologic flow

  6. A sensor for calcium uptake

    OpenAIRE

    Collins, Sean; Meyer, Tobias

    2010-01-01

    Mitochondria — the cell’s power plants — increase their energy production in response to calcium signals in the cytoplasm. A regulator of the elusive mitochondrial calcium channel has now been identified.

  7. Children's Bone Health and Calcium

    Science.gov (United States)

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

  8. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    Directory of Open Access Journals (Sweden)

    Chuxia Lin

    2012-01-01

    Full Text Available Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs, which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coastal ASLs. The projected climate change highlights the possibility of an increase in the frequency and severity of extreme weather events such as droughts and heavy rains, which is likely to accelerate the acid generation in some circumstances and increase the frequency and magnitude of acid discharge. Sea level rise as a result of global warming will cause additional problems with the coastal ASLs. This is a review article. The following aspects are covered: (a the overriding biogeochemical processes leading to acid sulfate-producing weathering, (b a brief introduction to the inland acid sulfate landscapes, (c a brief introduction to the coastal acid sulfate landscapes, (d the likely impacts of climate change on ASLs and (e the possible measures to combat climate change-induced environmental degradation in the identified key acid sulfate footprints. The projected climate change is like to significantly affect the acid sulfate landscapes in different ways. Appropriate management strategies and cost-effective technologies need to be developed in order to minimize the climate change-induced ecological degradation.

  9. Rat pro-opiomelanocortin contains sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Hoshina, H.; Hortin, G.; Boime, I.

    1982-07-02

    Intermediate lobes isolated from rat pituitary glands incorporated (/sup 35/S)sulfate into pro-opiomelanocortin and other adrenocorticotropic hormone-containing peptides. Incubation of intermediate lobes in medium containing the arginine analog canavanine inhibited the cleavage of pro-opiomelanocortin into smaller products. Pro-opiomelanocortin that accumulated in the presence of canavanine was also sulfated.

  10. Calcium ion channel and epilepsy

    Institute of Scientific and Technical Information of China (English)

    Yudan Lü; Weihong Lin; Dihui Ma

    2006-01-01

    OBJECTIVE: To review the relationship between calcium ion channel and epilepsy for well investigating the pathogenesis of epilepsy and probing into the new therapeutic pathway of epilepsy.DATA SOURCES: A computer-based online research Calcium ion channel and epilepsy related articles published between January 1994 and December 2006 in the CKNI and Wanfang database with the key words of "calcium influxion, epilepsy, calcium-channel blocker". The language was limited to Chinese. At the same time,related articles published between January 1993 and December 2006 in Pubmed were searched for on online with the key words of "calcium influxion, epilepsy" in English.STUDY SELECTION: The materials were selected firstly. Inclusive criteria: ① Studies related to calcium ion channel and the pat1hogenesis of epilepsy. ② Studies on the application of calcium ion channel blocker in the treatment of epilepsy. Exclusive criteria: repetitive or irrelated studies.DATA EXTRACTION: According to the criteria, 123 articles were retrieved and 93 were excluded due to repetitive or irrelated studies. Altogether 30 articles met the inclusive criteria, 11 of them were about the structure and characters of calcium ion channel, 10 about calcium ion channel and the pathogenesis of epilepsy and 9 about calcium blocker and the treatment of epilepsy.DATA SYNTHESIS: Calcium ion channels mainly consist of voltage dependent calcium channel and receptor operated calcium channel. Depolarization caused by voltage gating channel-induced influxion is the pathological basis of epileptic attack, and it is found in many studies that many anti-epileptic drugs have potential and direct effect to rivalizing voltage-dependent calcium ion channel.CONCLUSION: Calcium influxion plays an important role in the seizure of epilepsy. Some calcium antagonists seen commonly are being tried in the clinical therapy of epilepsy that is being explored, not applied in clinical practice. If there are enough evidences to

  11. Sulfates removal by the GYP-CIX process following lime treatment

    International Nuclear Information System (INIS)

    The treatment of acid mine drainage by limiting results in the discharge of water saturated in gypsum and containing residual metal concentrations. These waters may exceed drinking and irrigation water standards for TDS, sulfates and some metals. The scaling nature of the saturated gypsum solution makes it unsuitable for industrial use and makes further processing difficult and costly. This paper discusses a novel ion exchange process that is suitable to desalinate large volumes of mine and industrial waters with a TDS of up to 6,500 mg/l which is also high in calcium and sulfates, to meet effluent discharge specifications. The GYP-CIX process is a continuous fluidized bed ion-exchange process that effectively removes calcium sulfate from gypsum saturated waters. It uses low cost chemicals such as lime and sulfuric acid for resin regeneration. The only waste product is gypsum and the treated water produced meets standards for reuse or discharge. This process consists of a two stage operation. The first is the removal of cations in a multistage continuous loading train, using cation exchange resin. The second operation is the removal of anions, again in a multistage continuous loading train using anion exchange resin

  12. Scintillation properties of lead sulfate

    International Nuclear Information System (INIS)

    We report on the scintillation properties of lead sulfate (PbSO4), a scintillator that show promise as a high energy photon detector. It physical properties are well suited for gamma detection, as its has a density of 6.4 gm/cm3, a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO4 crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decays times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature fro 3,200 photons/MeV at +45 degrees C to 4, 900 photons/MeV at room temperature (+25 degrees C) and 68,500 photons/MeV at -145 degrees C. In an imperfect, 3 mm cube of a naturally occurring mineral form of PbSO4 (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that BGO. There are significant sample to sample variations of the light output among anglesite samples, so the light output of lead sulfate may improve when large synthetic crystals become available. 10 refs

  13. Solar Imagery - Chromosphere - Calcium

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset consists of full-disk images of the sun in Calcium (Ca) II K wavelength (393.4 nm). Ca II K imagery reveal magnetic structures of the sun from about...

  14. Analysis of tyrosine-O-sulfation

    DEFF Research Database (Denmark)

    Bundgaard, J.R.; Sen, J.W.; Johnsen, A.H.; Rehfeld, Jens Frederik

    2008-01-01

    Tyrosine O-sulfation was first described about 50 years ago as a post-translational modification of fibrinogen. In the following 30 years it was considered to be a rare modification affecting only a few proteins and peptides. However, in the beginning of the 1980s tyrosine (Tyr) sulfation was shown...... to be a common modification and since then an increasing number of proteins have been identified as sulfated. The target proteins belong to the classes of secretory, plasma membrane, and lysosomal proteins, which reflects the intracellular localization of the enzymes catalyzing Tyr sulfation, the...... to demonstrate the presence of radioactively labeled tyrosine. These techniques have been described in detail previously. The aim of this chapter is to present alternative analytical methods of Tyr sulfation than radioisotope incorporation before analysis Udgivelsesdato: 2008...

  15. Gaseous Sulfate Solubility in Glass: Experimental Method

    Energy Technology Data Exchange (ETDEWEB)

    Bliss, Mary

    2013-11-30

    Sulfate solubility in glass is a key parameter in many commercial glasses and nuclear waste glasses. This report summarizes key publications specific to sulfate solubility experimental methods and the underlying physical chemistry calculations. The published methods and experimental data are used to verify the calculations in this report and are expanded to a range of current technical interest. The calculations and experimental methods described in this report will guide several experiments on sulfate solubility and saturation for the Hanford Waste Treatment Plant Enhanced Waste Glass Models effort. There are several tables of sulfate gas equilibrium values at high temperature to guide experimental gas mixing and to achieve desired SO3 levels. This report also describes the necessary equipment and best practices to perform sulfate saturation experiments for molten glasses. Results and findings will be published when experimental work is finished and this report is validated from the data obtained.

  16. Impregnating Coal With Calcium Carbonate

    Science.gov (United States)

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

    1991-01-01

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

  17. Acidosis and Urinary Calcium Excretion

    DEFF Research Database (Denmark)

    Alexander, R Todd; Cordat, Emmanuelle; Chambrey, Régine;

    2016-01-01

    Metabolic acidosis is associated with increased urinary calcium excretion and related sequelae, including nephrocalcinosis and nephrolithiasis. The increased urinary calcium excretion induced by metabolic acidosis predominantly results from increased mobilization of calcium out of bone and...... renal tubule and then discuss why not all gene defects that cause renal tubular acidosis are associated with hypercalciuria and nephrocalcinosis....

  18. Modeling of sulfation of potassium chloride by ferric sulfate addition during grate-firing of biomass

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Aho, Martti;

    2013-01-01

    Potassium chloride, KCl, formed from critical ash-forming elements released during combustion may lead to severe ash deposition and corrosion problems in biomass-fired boilers. Ferric sulfate, Fe2(SO4)3 is an effective additive, which produces sulfur oxides (SO2 and SO3) to convert KCl to the less...... order to simulate the sulfation of KCl by ferric sulfate addition during grate-firing of biomass. The simulation results show good agreements with the experimental data obtained in a pilot-scale biomass grate-firing reactor, where different amounts of ferric sulfate was injected on the grate or into the...... freeboard. In addition, the simulations of elemental sulfur addition on the grate fit well with the experimental data. The results suggest that the SO3 released from ferric sulfate decomposition is the main contributor to KCl sulfation, and that the effectiveness of the ferric sulfate addition is sensitive...

  19. Metabolic Flexibility of Sulfate Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Caroline M. Plugge

    2011-05-01

    Full Text Available Dissimilatory sulfate-reducing prokaryotes (SRB are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas methanogenic Archaea would be expected to succeed in the deeper sulfate-depleted layers of the sediment. Where sediments are high in organic matter, sulfate is depleted at shallow sediment depths, and biogenic methane production will occur. In the absence of sulfate, many SRB ferment organic acids and alcohols, producing hydrogen, acetate, and carbon dioxide, and may even rely on hydrogen- and acetate-scavenging methanogens to convert organic compounds to methane. SRB can establish two different life styles, and these can be termed as sulfidogenic and acetogenic, hydrogenogenic metabolism. The advantage of having different metabolic capabilities is that it raises the chance of survival in environments when electron acceptors become depleted. In marine sediments, SRB and methanogens do not compete but rather complement each other in the degradation of organic matter.Also in freshwater ecosystems with sulfate concentrations of only 10-200 μM, sulfate is consumed efficiently within the top several cm of the sediments. Here, many of the δ-Proteobacteria present have the genetic machinery to perform dissimilatory sulfate reduction, yet they have an acetogenic, hydrogenogenic way of life.In this review we evaluate the physiology and metabolic mode of SRB in relation with their environment.

  20. Activation and transfer of sulfate in biological systems (1960)

    International Nuclear Information System (INIS)

    It examines in this review the successive stages of active sulfate formation and its role in biological synthesis of sulfuric esters. The possible role of active sulfate as intermediary in sulfate reduction is also discussed. (author)

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

    Science.gov (United States)

    Clark, Boyd Arthur

    tricalcium aluminate were observed. No crystalline magnesium-rich phases were detected by XRD. The products formed by hydration of tetracalcium aluminoferrite (Ca 2AlFeO5) and magnesium sulfate solutions were investigated by isothermal calorimetry, XRD and SEM analyses. Hydration reactions were carried out isothermally at temperatures from 25 to 80°C in 0.25M, 0.5M, 1.0M, 2.0M, and 3.0M magnesium sulfate solutions. Gypsum was the initial hydration product in all magnesium sulfate concentrations and was the only crystalline hydration product in 2.0M and 3.0M magnesium sulfate solutions. Monosulfate was the dominant crystalline phase produced over the entire temperature range when hydration was carried out in magnesium sulfate concentrations between 0.25M and 1.0M. No crystalline phases incorporating iron were observed regardless of magnesium sulfate concentration or temperature. Hydration in 1.0M MgSO 4 solution was more extensively investigated at 50°C. SEM observations indicated gypsum formed initially, consisting of fine particles (ettringite, and monosulfate were present at intermediate times. Monosulfate was the final crystalline hydration product. Amorphous solids produced include a calcium/iron-rich gel and a magnesium/aluminum/sulfate-rich phase. The calcium/iron-rich gel is the only iron-rich phase observed in the hydrated phase assemblage.

  2. Sodium Sulfate and Sodium Hydrogen Sulfate as Activating Agents for Hydration of Natural Anhydrite%硫酸钠与硫酸氢钠对天然硬石膏水化激发研究

    Institute of Scientific and Technical Information of China (English)

    闫勇; 高孝钱; 吴小俊; 檀杰; 郑翠红

    2011-01-01

    Sodium sulfate and sodium hydrogen sulfate were attempted to be used as activating agents for hydration of natural anhydrite. The activating efficiency of the two activating agents, as well as the mechanism of hydration of natural anhydrite was characterized by the means of scanning electronic microscopy, X-ray diffraction, infrared spectrum, thermogravimetric-differential thermal analysis, and determination of three-day hydration rate. The results showed that the efficiency of sodium hydrogen sulfate is notably superior to that of sodium sulfate. The three-day hydration rate of the natural anhydrite was determined to be as high as 41.8 % when 3 % sodium hydrogen sulfate was added, while the maximum three-day hydration rate of 32.7 % is achieved when 5 % sodium sulfate was applied. The activating mechanism for sodium sulfate and sodium hydrogen sulfate is based on the dissolution of calcium sulfate anhydrate and the subsequent re-crystallization of calcium sulfate dehydrate.%采用扫描电镜、X射线衍射、红外光谱、热重-差热分析以及3d水化率的测定技术,研究硫酸钠和硫酸氢钠两种不同激发剂对天然硬石膏水化的激发效果以及水化机理.结果表明:硫酸氢钠对天然硬石膏水化的激发效果明显优于硫酸钠;当硫酸钠加入量达到5%时,3d水化率值最大,为32.7%,而硫酸氢钠加入量为3%时,3d水化率高达41.8%.硫酸钠和硫酸氢钠对天然硬石膏水化激发机理基于硬石膏溶解和二水硫酸钙析出.

  3. Surfen, a small molecule antagonist of heparan sulfate

    OpenAIRE

    Schuksz, Manuela; Fuster, Mark M.; Brown, Jillian R.; Crawford, Brett E.; Ditto, David P.; Lawrence, Roger; Glass, Charles A; Wang, Lianchun; Tor, Yitzhak; Esko, Jeffrey D

    2008-01-01

    In a search for small molecule antagonists of heparan sulfate, we examined the activity of bis-2-methyl-4-amino-quinolyl-6-carbamide, also known as surfen. Fluorescence-based titrations indicated that surfen bound to glycosaminoglycans, and the extent of binding increased according to charge density in the order heparin > dermatan sulfate > heparan sulfate > chondroitin sulfate. All charged groups in heparin (N-sulfates, O-sulfates, and carboxyl groups) contributed to binding, consistent with...

  4. A Comparative Study on Several Models of Experimental Renal Calcium Oxalate Stones Formation in Rats

    Institute of Scientific and Technical Information of China (English)

    LIU Jihong; CAO Zhenggno; ZHANG Zhaohui; ZHOU Siwei; YE Zhangqun

    2007-01-01

    In order to compare the effects of several experimental renal calcium oxalate stones formation models in rats and to find a simple and convenient model with significant effect of calcium oxalate crystals deposition in the kidney, several rat models of renal calcium oxalate stones formation were induced by some crystal-inducing drugs (CID) including ethylene glycol (EG), ammonium chloride (AC), vitamin D3 [1α(OH)VitD3, alfacalcidol], calcium gluconate, ammonium oxalate, gentamicin sulfate, L-hydroxyproline. The rats were fed with drugs given singly or unitedly. At the end of experiment, 24-h urines were collected and the serum creatinine (Cr), blood urea nitrogen (BUN), the extents of calcium oxalate crystal deposition in the renal tissue, urinary calcium and oxalate excretion were measured. The serum Cr levels in the stone-forming groups were significantly higher than those in the control group except for the group EG+L-hydroxyproline, group calcium gluconate and group oxalate. Blood BUN concentration was significantly higher in rats fed with CID than that in control group except for group EG+L-hydroxyproline and group ammonium oxalate plus calcium gluconate. In the group of rats administered with EG plus Vitamin D3, the deposition of calcium oxalate crystal in the renal tissue and urinary calcium excretion were significantly greater than other model groups. The effect of the model induced by EG plus AC was similar to that in the group induced by EG plus Vitamin D3. EG plus Vitamin D3 or EG plus AC could stably and significantly induced the rat model of renal calcium oxalate stones formation.

  5. Effect of purification pretreatment on the recovery of magnetite from waste ferrous sulfate

    Science.gov (United States)

    Yu, Wang; Peng, Ying-lin; Zheng, Ya-jie

    2016-08-01

    The present study was conducted to elucidate the influence of impurities in waste ferrous sulfate on its recovery of magnetite. Ferrous sulfate solution was purified by the addition of NaOH solution to precipitate impurities, and magnetite was recovered from ferrous sulfate solution without and with purification pretreatment. Calcium hydroxide was added to the solution of ferrous sulfate as a precipitator. A mixed product of magnetite and gypsum was subsequently obtained by air oxidation and heating. Wet-milling was performed prior to magnetic separation to recover magnetite from the mixed products. The results show that with the purification pretreatment, the grade of iron in magnetite concentrate increased from 62.05% to 65.58% and the recovery rate of iron decreased from 85.35% to 80.35%. The purification pretreatment reduced the conglutination between magnetite and gypsum, which favors their subsequent magnetic separation. In summary, a higher-grade magnetite with a better crystallinity and a larger particle size of 2.35 μm was obtained with the purification pretreatment.

  6. Fruit Calcium: Transport and Physiology

    Science.gov (United States)

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

    2016-01-01

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

  7. Fruit Calcium: Transport and Physiology.

    Science.gov (United States)

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

    2016-01-01

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

  8. Calcium and calcitonin responses to calcium infusion in type I diabetes mellitus.

    OpenAIRE

    Amado, J. A.; C. Gomez; Obaya, S.; Otero, M; Gonzalez-Macias, J

    1987-01-01

    We studied calcium and calcium and calcitonin responses to intravenous calcium infusion (3 mg of elemental calcium/kg of body weight in 10 minutes) in 21 type I diabetic males and 17 age-matched normal males. Baseline total calcium, parathyroid hormone and calcitonin levels were normal in the diabetic group, but ionized calcium was lowered. Cortical bone status and osteocalcin levels were normal, suggesting a normal osteoblastic function. Total calcium and ionized calcium responses to calcium...

  9. DISTILLATION OF CALCIUM

    Science.gov (United States)

    Barton, J.

    1954-07-27

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

  10. Recrystallization of 223Ra with barium sulfate

    International Nuclear Information System (INIS)

    In this work, the kinetics of barium sulfate recrystallization has been studied in acidic 0.01 mol dm-3 sodium sulfate solution using 223Ra and 133Ba tracers at very low total radium concentration, i.e. less than 10-13 mol dm-3. It was found that the system follows the homogeneous recrystallization model and that recrystallization rates, inferred by the decrease of 223Ra and 133Ba in the aqueous solution, are fast. Therefore, even at very low concentrations, below the solubility limit, radium will be retained by barium sulfate-a mineral present in the deep underground repository. (author)

  11. Models of calcium signalling

    CERN Document Server

    Dupont, Geneviève; Kirk, Vivien; Sneyd, James

    2016-01-01

    This book discusses the ways in which mathematical, computational, and modelling methods can be used to help understand the dynamics of intracellular calcium. The concentration of free intracellular calcium is vital for controlling a wide range of cellular processes, and is thus of great physiological importance. However, because of the complex ways in which the calcium concentration varies, it is also of great mathematical interest.This book presents the general modelling theory as well as a large number of specific case examples, to show how mathematical modelling can interact with experimental approaches, in an interdisciplinary and multifaceted approach to the study of an important physiological control mechanism. Geneviève Dupont is FNRS Research Director at the Unit of Theoretical Chronobiology of the Université Libre de Bruxelles;Martin Falcke is head of the Mathematical Cell Physiology group at the Max Delbrück Center for Molecular Medicine, Berlin;Vivien Kirk is an Associate Professor in the Depar...

  12. Novel alkylsulfatases required for biodegradation of the branched primary alkyl sulfate surfactant 2-butyloctyl sulfate.

    Science.gov (United States)

    Ellis, Andrew J; Hales, Stephen G; Ur-Rehman, Naheed G A; White, Graham F

    2002-01-01

    Recent reports show that contrary to common perception, branched alkyl sulfate surfactants are readily biodegradable in standard biodegradability tests. We report here the isolation of bacteria capable of biodegrading 2-butyloctyl sulfate and the identification of novel enzymes that initiate the process. Enrichment culturing from activated sewage sludge yielded several strains capable of growth on 2-butyloctyl sulfate. Of these, two were selected for further study and identified as members of the genus Pseudomonas. Strain AE-A was able to utilize either sodium dodecyl sulfate (SDS) or 2-butyloctyl sulfate as a carbon and energy source for growth, but strain AE-D utilized only the latter. Depending on growth conditions, strain AE-A produced up to three alkylsulfatases, as shown by polyacrylamide gel electrophoresis zymography. Growth on either SDS or 2-butyloctyl sulfate or in nutrient broth produced an apparently constitutive, nonspecific primary alkylsulfatase, AP1, weakly active on SDS and on 2-butyloctyl sulfate. Growth on 2-butyloctyl sulfate produced a second enzyme, AP2, active on 2-butyloctyl sulfate but not on SDS, and growth on SDS produced a third enzyme, AP3, active on SDS but not on 2-butyloctyl sulfate. In contrast, strain AE-D, when grown on 2-butyloctyl sulfate (no growth on SDS), produced a single enzyme, DP1, active on 2-butyloctyl sulfate but not on SDS. DP1 was not produced in broth cultures. DP1 was induced when residual 2-butyloctyl sulfate was present in the growth medium, but the enzyme disappeared when the substrate was exhausted. Gas chromatographic analysis of products of incubating 2-butyloctyl sulfate with DP1 in gels revealed the formation of 2-butyloctanol, showing the enzyme to be a true sulfatase. In contrast, Pseudomonas sp. strain C12B, well known for its ability to degrade linear SDS, was unable to grow on 2-butyloctyl sulfate, and its alkylsulfatases responsible for initiating the degradation of SDS by releasing the parent

  13. Separation of plutonium from sulphate bearing analytical waste by co-precipitation with calcium oxalate

    International Nuclear Information System (INIS)

    A simple approach for separation of Plutonium from sulfate bearing Analytical waste is presented here. The analytical waste is generated during analysis of plutonium using the Drummond-Grand potentiometric method mainly contains sulphate ions. The removal and recovery of plutonium from this waste is important due to radio toxicity associated with it as well as its strategic importance. Plutonium is co-precipitated with calcium oxalate by calcium nitrate and potassium oxalate mixture. The recovery is almost complete (99.96%). This method is adapted for routine use in our laboratory. (author)

  14. Effect of different retarders on the hydration of calcium sulfoaluminate eco-cement pastes

    OpenAIRE

    García-Maté, Marta; De la Torre, Ángeles G.; Aranda, Miguel A. G.; Santacruz, Isabel

    2014-01-01

    The manufacture of Calcium SulfoAluminate (CSA) cements is more environmentally friendly than that of OPC [1] as their production releases up to 40% less CO2 than the latter. The main performances of CSA cements are fast setting time, good-chemical resistance properties and high early strengths. CSA cements are prepared by mixing CSA clinker with different amounts of a calcium sulfate set regulator such as gypsum (CaSO4•2H2O), bassanite (CaSO4•½H2O), or anhydrite (CaSO4), or mixtures of th...

  15. Influence of sulfate, Ca, and Mg on the acute toxicity of potassium dichromate to Daphnia similis

    Energy Technology Data Exchange (ETDEWEB)

    Hosokawa, Mamoru; Kuroda, Koichi (Osaka City Inst. of Public Health and Environmental Sciences (Japan)); Endo, Ginji; Horiguchi, Shunichi (Osaka City Univ. Medical School (Japan))

    1991-03-01

    In the Daphnia test which is commonly employed for assessing effects of chemicals to aquatic environments, it is well known that the toxicity of chemicals is variable with test animals and also with the chemistry of test waters. However, it is not clear what constituents in water affect toxicity of chemicals. The authors report here experimental results which show that sulfate, calcium and magnesium, commonly contained in aquatic environments, decrease the toxicity of K{sub 2}Cr{sub 2}O{sub 7} which is recommended as a reference toxicant in the acute toxicity test.

  16. ROE Wet Sulfate Deposition 2009-2011

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet sulfate deposition in kilograms per hectare from 2009 to 2011. Summary data in this indicator were provided by EPA’s...

  17. Sulfated cellulose thin films with antithrombin affinity

    Directory of Open Access Journals (Sweden)

    2009-11-01

    Full Text Available Cellulose thin films were chemically modified by in situ sulfation to produce surfaces with anticoagulant characteristics. Two celluloses differing in their degree of polymerization (DP: CEL I (DP 215–240 and CEL II (DP 1300–1400 were tethered to maleic anhydride copolymer (MA layers and subsequently exposed to SO3•NMe3 solutions at elevated temperature. The impact of the resulting sulfation on the physicochemical properties of the cellulose films was investigated with respect to film thickness, atomic composition, wettability and roughness. The sulfation was optimized to gain a maximal surface concentration of sulfate groups. The scavenging of antithrombin (AT by the surfaces was determined to conclude on their potential anticoagulant properties.

  18. Potassium aquaterbium(III oxalate sulfate

    Directory of Open Access Journals (Sweden)

    Ya-Guang Sun

    2009-07-01

    Full Text Available Single crystals of KTb(C2O4(SO4(H2O, potassium aquaterbium(III oxalate sulfate, were obtained under hydrothermal conditions. In the crystal structure, the Tb(III atom is coordinated by four O atoms from two oxalate anions, three O atoms from three sulfate anions and one O atom from a water molecule within a TbO8 distorted square antiprismatic coordination. The potassium and terbium(III atoms are bridged by the oxalate and sulfate groups, forming a three-dimensional structure. The coordination mode of the oxalate has not yet been reported. O—H...O hydrogen bonding between the water molecules and the oxygen atoms of oxalate and sulfate anions is also observed.

  19. Reverse calcium affinity purification of Fab with calcium derivatized hydroxyapatite

    OpenAIRE

    Gagnon, Pete; Cheung, Chia-wei; Yazaki, Paul J.

    2009-01-01

    This study introduces the application of calcium-derivatized hydroxyapatite for purification of Fab. Fab binds to native hydroxyapatite but fails to bind to the calcium derivatized form. IgG, Fc, and most other protein contaminants bind to the calcium form. This supports Fab purification by a simple flow-through method that achieves greater than 95% purity from papain digests and mammalian cell culture supernatants. Alternatively, Fab can be concentrated on native hydroxyapatite then eluted s...

  20. Chlorophenol Degradation Coupled to Sulfate Reduction

    OpenAIRE

    Häggblom, M M; Young, L. Y.

    1991-01-01

    We studied chlorophenol degradation under sulfate-reducing conditions with an estuarine sediment inoculum. These cultures degraded 0.1 mM 2-, 3-, and 4-chlorophenol and 2,4-dichlorophenol within 120 to 220 days, but after refeeding with chlorophenols degradation took place in 40 days or less. Further refeeding greatly enhanced the rate of degradation. Sulfate consumption by the cultures corresponded to the stoichiometric values expected for complete oxidation of the chlorophenol to CO2. Forma...

  1. Heparan Sulfate Dependent Mechanisms of Amyloidosis

    OpenAIRE

    Noborn, Fredrik

    2012-01-01

    A common theme in amyloid disorders is the deposition of disease-specific protein aggregates in tissues. Amyloid proteins bind to heparan sulfate (HS), a sulfated glycosaminoglycan, and HS has been found to promote the aggregation process. The present work relates to HS mediated mechanisms of amyloidosis, particularly transthyretin (TTR) amyloidosis, AA-amyloidosis and Alzheimer’s disease (AD). TTR is a transport protein present in the blood and cerebrospinal fluid, which under unclear circum...

  2. Glycochenodeoxycholic acid inhibits calcium phosphate precipitation in vitro by preventing the transformation of amorphous calcium phosphate to calcium hydroxyapatite.

    OpenAIRE

    Qiu, S M; Wen, G.; Hirakawa, N; Soloway, R D; Hong, N K; Crowther, R S

    1991-01-01

    Calcium hydroxyapatite can be a significant component of black pigment gallstones. Diverse molecules that bind calcium phosphate inhibit hydroxyapatite precipitation. Because glycine-conjugated bile acids, but not their taurine counterparts, bind calcium phosphate, we studied whether glycochenodeoxycholic acid inhibits calcium hydroxyapatite formation. Glycochenodeoxycholic acid (2 mM) totally inhibited transformation of amorphous calcium phosphate microprecipitates to macroscopic crystalline...

  3. Hormonal control of sulfate uptake and assimilation.

    Science.gov (United States)

    Koprivova, Anna; Kopriva, Stanislav

    2016-08-01

    Plant hormones have a plethora of functions in control of plant development, stress response, and primary metabolism, including nutrient homeostasis. In the plant nutrition, the interplay of hormones with responses to nitrate and phosphate deficiency is well described, but relatively little is known about the interaction between phytohormones and regulation of sulfur metabolism. As for other nutrients, sulfate deficiency results in modulation of root architecture, where hormones are expected to play an important role. Accordingly, sulfate deficiency induces genes involved in metabolism of tryptophane and auxin. Also jasmonate biosynthesis is induced, pointing to the need of increase the defense capabilities of the plants when sulfur is limiting. However, hormones affect also sulfate uptake and assimilation. The pathway is coordinately induced by jasmonate and the key enzyme, adenosine 5'-phosphosulfate reductase, is additionally regulated by ethylene, abscisic acid, nitric oxid, and other phytohormones. Perhaps the most intriguing link between hormones and sulfate assimilation is the fact that the main regulator of the response to sulfate starvation, SULFATE LIMITATION1 (SLIM1) belongs to the family of ethylene related transcription factors. We will review the current knowledge of interplay between phytohormones and control of sulfur metabolism and discuss the main open questions. PMID:26810064

  4. Divergent Synthesis of Heparan Sulfate Oligosaccharides.

    Science.gov (United States)

    Dulaney, Steven B; Xu, Yongmei; Wang, Peng; Tiruchinapally, Gopinath; Wang, Zhen; Kathawa, Jolian; El-Dakdouki, Mohammad H; Yang, Bo; Liu, Jian; Huang, Xuefei

    2015-12-18

    Heparan sulfates are implicated in a wide range of biological processes. A major challenge in deciphering their structure and activity relationship is the synthetic difficulties to access diverse heparan sulfate oligosaccharides with well-defined sulfation patterns. In order to expedite the synthesis, a divergent synthetic strategy was developed. By integrating chemical synthesis and two types of O-sulfo transferases, seven different hexasaccharides were obtained from a single hexasaccharide precursor. This approach combined the flexibility of chemical synthesis with the selectivity of enzyme-catalyzed sulfations, thus simplifying the overall synthetic operations. In an attempt to establish structure activity relationships of heparan sulfate binding with its receptor, the synthesized oligosaccharides were incorporated onto a glycan microarray, and their bindings with a growth factor FGF-2 were examined. The unique combination of chemical and enzymatic approaches expanded the capability of oligosaccharide synthesis. In addition, the well-defined heparan sulfate structures helped shine light on the fine substrate specificities of biosynthetic enzymes and confirm the potential sequence of enzymatic reactions in biosynthesis. PMID:26574650

  5. EDTA-insoluble, calcium-binding proteoglycan in bovine bone

    Science.gov (United States)

    Hashimoto, Y.; Lester, G. E.; Caterson, B.; Yamauchi, M.

    1995-01-01

    A calcium ion precipitable, trypsin-generated proteoglycan fragment has been isolated from the demineralized, EDTA-insoluble matrices of bone. The demineralized matrix was completely digested with trypsin, increasing concentrations of CaCl2 were added to the supernatant, and the resulting precipitates were analyzed. The amount of precipitate gradually increased with higher concentrations of calcium and was reversibly solubilized by EDTA. After molecular sieve and anion exchange chromatography, a proteoglycan-containing peak was obtained. Immunochemical analysis showed that this peak contained chondroitin 4-sulfate and possibly keratan sulfate. Amino acid analysis showed that this proteoglycan contained high amounts of aspartic acid/asparagine (Asx), serine (Ser), glutamic acid/glutamine (Glx), proline (Pro), and glycine (Gly); however, it contained little leucine (Leu) which suggests that it is not a member of the leucine-rich small proteoglycan family. In addition, significant amounts of phosphoserine (P-Ser) and hydroxyproline (Hyp) were identified in hydrolysates of this fraction. A single band (M(r) 59 kDa) was obtained on SDS-PAGE that stained with Stains-all but not with Coomassie Brilliant Blue R-250. If bone powder was trypsinized prior to demineralization, this proteoglycan-containing fraction was not liberated. Collectively, these results indicate that a proteoglycan occurs in the demineralized matrix that is precipitated with CaCl2 and is closely associated with both mineral and collagen matrices. Such a molecule might facilitate the structural network for the induction of mineralization in bone.

  6. Calcium – how and why?

    Indian Academy of Sciences (India)

    J K Jaiswal

    2001-09-01

    Calcium is among the most commonly used ions, in a multitude of biological functions, so much so that it is impossible to imagine life without calcium. In this article I have attempted to address the question as to how calcium has achieved this status with a brief mention of the history of calcium research in biology. It appears that during the origin and early evolution of life the Ca2+ ion was given a unique opportunity to be used in several biological processes because of its unusual physical and chemical properties.

  7. Calcium addition in straw gasification

    DEFF Research Database (Denmark)

    Risnes, H.; Fjellerup, Jan Søren; Henriksen, Ulrik Birk; Moilanen, A.; Norby, P.; Papadakis, K.; Posselt, D.; Sørensen, L. H.

    2003-01-01

    The present work focuses on the influence of calcium addition in gasification. The inorganic¿organic element interaction as well as the detailed inorganic¿inorganic elements interaction has been studied. The effect of calcium addition as calcium sugar/molasses solutions to straw significantly...... affected the ash chemistry and the ash sintering tendency but much less the char reactivity. Thermo balance test are made and high-temperature X-ray diffraction measurements are performed, the experimental results indicate that with calcium addition major inorganic¿inorganic reactions take place very late...

  8. Calcium Phosphate Biomaterials: An Update

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Current calcium phosphate (CaP) biomaterials for bone repair, substitution, augmentation and regeneration include hydroxyapatite ( HA ) from synthetic or biologic origin, beta-tricalcium phosphate ( β-TCP ) , biphasic calcium phosphate (BCP), and are available as granules, porous blocks, components of composites (CaP/polymer) cements, and as coatings on orthopedic and dental implants. Experimental calcium phosphate biomaterials include CO3- and F-substituted apatites, Mg-and Zn-substituted β-TCP, calcium phosphate glasses. This paper is a brief review of the different types of CaP biomaterials and their properties such as bioactivity, osteoconductivity, osteoinductivity.

  9. 21 CFR 573.240 - Calcium periodate.

    Science.gov (United States)

    2010-04-01

    ... with calcium hydroxide or calcium oxide to form a substance consisting of not less than 60 percent by... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium periodate. 573.240 Section 573.240 Food... Additive Listing § 573.240 Calcium periodate. The food additive calcium periodate may be safely used...

  10. 21 CFR 573.260 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 573.260 Section 573.260 Food and... Listing § 573.260 Calcium silicate. Calcium silicate, including synthetic calcium silicate, may be safely used as an anticaking agent in animal feed, provided that the amount of calcium silicate does...

  11. Calcium measurement methods

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-09-01

    Full Text Available Rightly stressed by prof. Wolfgang Walz in the Preface to the series Neuromethods series, the “careful application of methods is probably the most important step in the process of scientific inquiry”. Thus, I strongly suggest to all those interested in calcium signaling and especially to the new-comers in the hot topic of neuroscience (which has so much space even in science-society debate for its implications in legal issues and in the judge-decision process to take profit from this so well edited book. I am saying this since prof. Verkhratsky and prof. Petersen......

  12. A Large Chondroitin Sulfate Proteoglycan, Versican, in Porcine Predentin.

    Science.gov (United States)

    Okahata, Saori; Yamamoto, Ryuji; Yamakoshi, Yasuo; Fukae, Makoto

    2011-01-01

    Proteoglycans and their constituent glycosaminoglycan (GAG) have been proposed to be involved in the inhibition of mineralization in unmineralized tissue, predentin. Among the proteoglycans secreted by odontoblasts, we focused on the large chondroitin sulfate proteoglycan, versican, for its large binding capacity for calcium ions. The aims of this study were the determination of the full-length sequence and splicing variants of the porcine versican, and the detection of versican in the porcine predentin. The complete coding sequence of the porcine versican mRNA was cloned to be 11,775 nucleotides long and encode 3,924 amino acids, and four splicing variants, V0, V1, V2 and V3, were characterized in the isolated porcine cartilage cells. The number of potential GAG attachment sites was 15 in the V0 variant, 13 in the V1 variant, 2 in the V2 variant and 0 in the V3 variant. They were deposited in DDBJ. The V1 variant was determined by RT-PCR in the odontoblasts, dental papilla cells, dental follicle cells, periodontal ligament cells, dental pulp cells, and gingival cells of pigs, although a small amount of the V0 valiant was found in the dental papilla cells. The predentin was prepared from developing porcine permanent incisor tooth germs and its soluble proteins were extracted in order to be partially characterized by protein and proteinase profiles. The versican V1 cleavage products were detected in the predentin extract by Western blotting analysis. These results suggested that the versican splice variant V1 implicates both the control of the mineralization and the activities of the predentin metalloproteinases, because it has 13 GAG chains that bind a large amount of calcium. PMID:22200993

  13. Extraction and purification of calcium-activated photoproteins from the ctenophores Mnemiopsis sp. and Beroe ovata

    Energy Technology Data Exchange (ETDEWEB)

    Ward, W.W.; Seliger, H.H.

    1974-01-01

    Calcium-activated bioluminescent ''photoproteins'' from the ctenophores Mnemiopsis sp. and Beroue ovata have been isolated by extraction with EDTA and purified 3800-fold and 7800-fold, respectively. The steps consisted of ammonium sulfate and protoamine sulfate treatments, followed by several steps of ion-exchange, gel filtration, and solubility chromatography. The purified photoproteins are virtually homogeneous by the criterion of sodium dodecyl sulfate polyacrylamide gel electrophoresis. Approximately 30,000 adult specimens of Mnemiopsis, totalling more than 600 kg wet wt, yielded 2 mg of purified photoprotein. Mnemiopsis photoprotein has been resolved into two functionally identical forms (''isoproteins''), termed mnemiopsin-1 and mnemiopsin-2, by chromatography on DEAE-cellulose. Berovin, the Beroue photoprotein, chromatographs as a single symmetrical peak under the same conditions.

  14. Extracellular calcium sensing and extracellular calcium signaling

    Science.gov (United States)

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

    2001-01-01

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

  15. NMR-based conformation and dynamics of a tetrasaccharide-repeating sulfated fucan substituted by different counterions.

    Science.gov (United States)

    Soares, Paulo A G; Queiroz, Ismael N L; Santos, Gustavo R C; Mourão, Paulo A S; Pomin, Vitor H

    2016-11-01

    The sulfated fucan from the sea urchin Lytechinus variegatus is composed of the repetitive sequence [-3)-α-l-Fucp-4( OSO3-)-(1-3)-α-l-Fucp-2,4-di( OSO3-)-(1-3)-α-l-Fucp-2( OSO3-)-(1-3)-α-l-Fucp-2( OSO3-)-(1-]n . Conformation (of rings and chains) and dynamics of this tetrasaccharide-repeating sulfated fucan substituted by Na(+) , Ca(2+) , and Li(+) as counterions have been examined through experiments of liquid-state nuclear magnetic resonance spectroscopy. Scalar coupling and nuclear Overhauser effect (NOE)-based data have confirmed that all composing units occur as (1) C4 chair conformer regardless of the cation type, unit position within the repeating sequence, and sulfation type. Chain conformation determined by NOE signal pattern assisted by molecular modeling for a theoretical octasaccharide has shown a similar linear 3D structure for the three differently substituted forms. Data derived from spin-relaxation measurements have indicated a contribution of counterion type to dynamics. The calcium-based preparation has shown the highest mobility while the sodiated one showed the lowest mobility. The set of results from this work suggests that counterion type can affect the physicochemical properties of the structurally well-defined sulfated fucan. The counterion effect seems to impact more on the structural mobility than on average conformation of the studied sulfated glycan in solution. PMID:27434759

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

    Directory of Open Access Journals (Sweden)

    S. Vaitheeswari

    2015-06-01

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

  17. Compartmentalization of the submembrane calcium activity during calcium influx and its significance in transmitter release.

    OpenAIRE

    Simon, S M; Llinás, R R

    1985-01-01

    Quantitative modeling indicates that, in presynaptic terminals, the intracellular calcium concentration profile during inward calcium current is characterized by discrete peaks of calcium immediately adjacent to the calcium channels. This restriction of intracellular calcium concentration suggests a remarkably well specified intracellular architecture such that calcium, as a second messenger, may regulate particular intracellular domains with a great degree of specificity.

  18. Temperature dependence of crystals conductivity both potassium sulfates and ammonium sulfates

    International Nuclear Information System (INIS)

    In the work the results of temperature dependence of conductivity of crystals both potassium sulfate and ammonium sulfate are given. The superficial specific conductivity and its dependence on width of a backlash between the central and ring electrodes are determined. (author)

  19. Solubility in aqueous system of potassium sulfate, cadmium sulfate at 50 deg C

    International Nuclear Information System (INIS)

    Solubility in system potassium sulfate-cadmium sulfate-water at 50 deg C is studied using isothermal method. Crystallization limits of K2SO4, CdSO4x8/3H2O double salt 2K2SO4x2CdSO4x3H2O at 50 deg C are determined

  20. 21 CFR 524.1484e - Neomycin sulfate and polymyxin B sulfate ophthalmic solution.

    Science.gov (United States)

    2010-04-01

    ... ophthalmic solution. 524.1484e Section 524.1484e Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1484e Neomycin sulfate and polymyxin B sulfate ophthalmic solution....

  1. Sanfilippo disease type D: deficiency of N-acetylglucosamine-6-sulfate sulfatase required for heparan sulfate degradation.

    OpenAIRE

    Kresse, H.; Paschke, E; von Figura, K; Gilberg, W; Fuchs, W

    1980-01-01

    Skin fibroblasts from two patients who had symptoms of the Sanfilippo syndrome (mucopolysaccharidosis III) accumulated excessive amounts of heparan sulfate and were unable to release sulfate from N-acetylglucosamine-6-sulfate linkages in heparan sulfate-derived oligosaccharides. Keratan sulfate-derived oligosaccharides bearing the same residue at the nonreducing end and p-nitrophenyl-6-sulfo-2-acetamido-2-deoxy-beta-D-glucopyranoside were degraded normally. Kinetic differences between th sulf...

  2. Vitamin D, Calcium, and Bone Health

    Science.gov (United States)

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

  3. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  4. Calcium transport in turtle bladder

    International Nuclear Information System (INIS)

    Unidirectional 45Ca fluxes were measured in the turtle bladder under open-circuit and short-circuit conditions. In the open-circuited state net calcium flux (JnetCa) was secretory (serosa to mucosa). Ouabain reversed JnetCa to an absorptive flux. Amiloride reduced both fluxes such that JnetCa was not significantly different from zero. Removal of mucosal sodium caused net calcium absorption; removal of serosal sodium caused calcium secretion. When bladders were short circuited, JnetCa decreased to approximately one-third of control value but remained secretory. When ouabain was added under short-circuit conditions, JnetCa was similar in magnitude and direction to ouabain under open-circuited conditions (i.e., absorptive). Tissue 45Ca content was ≅30-fold lower when the isotope was placed in the mucosal bath, suggesting that the apical membrane is the resistance barrier to calcium transport. The results obtained in this study are best explained by postulating a Ca2+-ATPase on the serosa of the turtle bladder epithelium and a sodium-calcium antiporter on the mucosa. In this model, the energy for calcium movement would be supplied, in large part, by the Na+-K+-ATPase. By increasing cell sodium, ouabain would decrease the activity of the mucosal sodium-calcium exchanger (or reverse it), uncovering active calcium transport across the serosa

  5. An Improved Calcium Flame Test.

    Science.gov (United States)

    Pearson, Robert S.

    1985-01-01

    Indicates that the true red color of calcium can be obtained (using the procedure described by Sorm and Logowski) if the calcium ion solution is mixed with an equal volume of saturated ammonium bromide solution. Suggestions for flame tests of other elements are also noted. (JN)

  6. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    OpenAIRE

    Choksi Krishna; Shenoy Ashoka M; A. R. Shabharaya; Lala Minaxi

    2011-01-01

    The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg) and calcium gluconate (5 mg/kg) were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg) to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate cou...

  7. High rates of sulfate reduction in a low-sulfate hot spring microbial mat are driven by a low level of diversity of sulfate-respiring microorganisms

    DEFF Research Database (Denmark)

    Dillon, Jesse G; Fishbain, Susan; Miller, Scott R;

    2007-01-01

    The importance of sulfate respiration in the microbial mat found in the low-sulfate thermal outflow of Mushroom Spring in Yellowstone National Park was evaluated using a combination of molecular, microelectrode, and radiotracer studies. Despite very low sulfate concentrations, this mat community...

  8. Differentiating seawater and groundwater sulfate attack in Portland cement mortars

    International Nuclear Information System (INIS)

    The study reported in this article deals with understanding the physical, chemical and microstructural differences in sulfate attack from seawater and groundwater. Portland cement mortars were completely immersed in solutions of seawater and groundwater. Physical properties such as length, mass, and compressive strength were monitored periodically. Thermal analysis was used to study the relative amounts of phases such as ettringite, gypsum, and calcium hydroxide, and microstructural studies were conducted by scanning electron microscopy. Portland cement mortars performed better in seawater solution compared to groundwater solution. The difference in performance could be attributed to the reduction in the quantity of the expansive attack products (gypsum and ettringite). The high Cl concentration of seawater could have played an important role by binding the C3A to form chloroaluminate compounds, such as Friedel's salt (detected in the microstructural studies), and also by lowering the expansive potential of ettringite. Furthermore, the thicker layer of brucite forming on the specimens in seawater could have afforded better protection against ingress of the solution than in groundwater

  9. The effect of sulfate activation on the early age hydration of BFS:PC composite cement

    Science.gov (United States)

    Collier, N. C.; Li, X.; Bai, Y.; Milestone, N. B.

    2015-09-01

    Blast furnace slag/Portland cement composites are routinely used for immobilising intermediate level nuclear wastes in the UK. Using high cement replacement levels reduces hydration exotherm and lowers pH. Although a lower grout pH will be beneficial in reducing the corrosion of certain encapsulated reactive metals such as aluminium, the degree of slag reaction will also be lower which may result in the formation of less hydration products and which in turn may reduce the capacity to immobilise waste ions. Adding neutral salts such as calcium and sodium sulfate to the composite cement can potentially increase slag activation without significantly altering the pH of the cement matrix. Thus the corrosion of any encapsulated metals would not be affected. This paper describes some of the properties of a hydrated 9:1 blast furnace slag:Portland cement matrix containing added sulfates of calcium and sodium. The findings show that all additives caused an increase in the amount of slag that reacted when cured for up to 28 days. This produced more material able to chemically bind waste ions. Activation with gypsum produced the highest rate of slag reaction.

  10. The effect of sulfate activation on the early age hydration of BFS:PC composite cement

    Energy Technology Data Exchange (ETDEWEB)

    Collier, N.C., E-mail: nick.collier@sheffield.ac.uk; Li, X.; Bai, Y.; Milestone, N.B.

    2015-09-15

    Blast furnace slag/Portland cement composites are routinely used for immobilising intermediate level nuclear wastes in the UK. Using high cement replacement levels reduces hydration exotherm and lowers pH. Although a lower grout pH will be beneficial in reducing the corrosion of certain encapsulated reactive metals such as aluminium, the degree of slag reaction will also be lower which may result in the formation of less hydration products and which in turn may reduce the capacity to immobilise waste ions. Adding neutral salts such as calcium and sodium sulfate to the composite cement can potentially increase slag activation without significantly altering the pH of the cement matrix. Thus the corrosion of any encapsulated metals would not be affected. This paper describes some of the properties of a hydrated 9:1 blast furnace slag:Portland cement matrix containing added sulfates of calcium and sodium. The findings show that all additives caused an increase in the amount of slag that reacted when cured for up to 28 days. This produced more material able to chemically bind waste ions. Activation with gypsum produced the highest rate of slag reaction.

  11. The effect of sulfate activation on the early age hydration of BFS:PC composite cement

    International Nuclear Information System (INIS)

    Blast furnace slag/Portland cement composites are routinely used for immobilising intermediate level nuclear wastes in the UK. Using high cement replacement levels reduces hydration exotherm and lowers pH. Although a lower grout pH will be beneficial in reducing the corrosion of certain encapsulated reactive metals such as aluminium, the degree of slag reaction will also be lower which may result in the formation of less hydration products and which in turn may reduce the capacity to immobilise waste ions. Adding neutral salts such as calcium and sodium sulfate to the composite cement can potentially increase slag activation without significantly altering the pH of the cement matrix. Thus the corrosion of any encapsulated metals would not be affected. This paper describes some of the properties of a hydrated 9:1 blast furnace slag:Portland cement matrix containing added sulfates of calcium and sodium. The findings show that all additives caused an increase in the amount of slag that reacted when cured for up to 28 days. This produced more material able to chemically bind waste ions. Activation with gypsum produced the highest rate of slag reaction

  12. Calcium Deposits in the Crayfish, Cherax quadricarinatus: Microstructure Versus Elemental Distribution.

    Science.gov (United States)

    Luquet, Gilles; Dauphin, Yannicke; Percot, Aline; Salomé, Murielle; Ziegler, Andreas; Fernández, Maria S; Arias, José L

    2016-02-01

    The crayfish Cherax quadricarinatus stores calcium ions, easily mobilizable after molting, for calcifying parts of the new exoskeleton. They are chiefly stored as amorphous calcium carbonate (ACC) during each premolt in a pair of gastroliths synthesized in the stomach wall. How calcium carbonate is stabilized in the amorphous state in such a biocomposite remains speculative. The knowledge of the microstructure at the nanometer level obtained by field emission scanning electron microscopy and atomic force microscopy combined with scanning electron microscopy energy-dispersive X-ray spectroscopy, micro-Raman and X-ray absorption near edge structure spectroscopy gave relevant information on the elaboration of such an ACC-stabilized biomineral. We observed nanogranules distributed along chitin-protein fibers and the aggregation of granules in thin layers. AFM confirmed the nanolevel structure, showing granules probably surrounded by an organic layer and also revealing a second level of aggregation as described for other crystalline biominerals. Raman analyses showed the presence of ACC, amorphous calcium phosphate, and calcite. Elemental analyses confirmed the presence of elements like Fe, Na, Mg, P, and S. P and S are heterogeneously distributed. P is present in both the mineral and organic phases of gastroliths. S seems present as sulfate (probably as sulfated sugars), sulfonate, sulfite, and sulfoxide groups and, in a lesser extent, as sulfur-containing amino acids. PMID:26818557

  13. Formation of the natural sulfate aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Kerminen, V.M.; Hillamo, R.; Maekinen, M.; Virkkula, A.; Maekelae, T.; Pakkanen, T. [Helsinki Univ. (Finland). Dept. of Physics

    1996-12-31

    Anthropogenic sulfate aerosol, together with particles from biomass burning, may significantly reduce the climatic warming due to man-made greenhouse gases. The radiative forcing of aerosol particles is based on their ability to scatter and absorb solar radiation (direct effect), and on their influences on cloud albedos and lifetimes (indirect effect). The direct aerosol effect depends strongly on the size, number and chemical composition of particles, being greatest for particles of 0.1-1 {mu}m in diameter. The indirect aerosol effect is dictated by the number of particles being able to act as cloud condensation nuclei (CCN). For sulfate particles, the minimum CCN size in tropospheric clouds is of the order of 0.05-0.2 {mu}m. To improve aerosol parameterizations in future climate models, it is required that (1) both primary and secondary sources of various particle types will be characterized at a greater accuracy, and (2) the influences of various atmospheric processes on the spatial and temporal distribution of these particles and their physico-chemical properties are known much better than at the present. In estimating the climatic forcing due to the sulfate particles, one of the major problems is to distinguish between sulfur from anthropogenic sources and that of natural origin. Global emissions of biogenic and anthropogenic sulfate pre-cursors are comparable in magnitude, but over regional scales either of these two source types may dominate. The current presentation is devoted to discussing the natural sulfate aerosol, including the formation of sulfur-derived particles in the marine environment, and the use of particulate methanesulfonic acid (MSA) as a tracer for the natural sulfate

  14. 2-Amino­pyrimidinium hydrogen sulfate

    OpenAIRE

    Elboulali, Adel; Akriche, Samah Toumi; Salem S. Al-Deyab; Rzaigui, Mohamed

    2011-01-01

    In the crystal structure of the title compound, C4H6N3 +·HSO4 −, hydrogen sulfate anions self-assemble through O—H⋯O hydrogen bonds, forming chains along the b axis, while the cations form centrosymmetric pairs via N—H⋯N hydrogen bonds. The 2-amino­pyrimidinium pairs are linked to the sulfate anions via N—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (10 ). In addition, weak inter­molecular C—H⋯O contacts generate a three-dimensional network.

  15. On the evaporation of ammonium sulfate solution

    Energy Technology Data Exchange (ETDEWEB)

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

  16. Radiation damage in calcium sulfate; Danos de radiacao em sulfato de calcio

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Antonio Roberto Pereira Leite

    1977-12-15

    We used the techniques of Electron Paramagnetic Resonance (EPR) to study the free radicals produced by X-radiation in natural crystals of Gypsum (CaSO{sub 4}2H{sub 2}0). We observed the formation of four free radicals. The spectra of these radicals are overlapped, being separated by power and temperature variation measurements. Two radicals were univocal identified, as being of OH{sup +} and 0{sub 2}H{sup +}. We suggest the assignment of SO{sub 4}{sup -} and O{sub 2}{sup -} to two other radicals. From angular variation measurements, we determined the components of tensors {r_reversible}g and {r_reversible}A of the radicals OH{sup -} and O{sub 2}H{sup -}. (author)

  17. Conversion of phosphogypsum to potassium sulfate and calcium carbonate in aqueous solution

    Directory of Open Access Journals (Sweden)

    Ennaciri Y.

    2013-09-01

    Full Text Available The dissociation of the phosphogysum by the liquid route which is the object of our work, is most appropriate and little expensive. Indeed, it leads to materials of direct application. The present work has for objective to study the decomposition of the phosphogypsum by the soft chemistry into valuable products such as K2SO4 and CaCO3. K2SO4 is a fertilizer which is highly recommended in the field of the agriculture, while CaCO3 can be used in the fields of the industry (cement and the environment. According to the obtained results, we notice that the decomposition of the phosphogypsum in aqueous solution is very workable, reproducible, inexpensive and it is an ecologically interesting reaction. This reaction is made at room temperature and in aqueous environment, by giving two valuable products K2SO4 and CaCO3. The reaction is total after one hour and a half.

  18. Sulfato de calcio: propiedades y aplicaciones clínicas Calcium sulfate: properties and clinical applications

    OpenAIRE

    López, J; M Alarcón

    2011-01-01

    Durante más de cien años el sulfato de calcio se ha distinguido de otros biomateriales, por ser uno de los materiales aloplásticos más simples y que presenta la más larga historia clínica como material sintético. Entre sus principales propiedades destacan que es de fácil obtención, capacidad de osteoconducción, es totalmente absorbible, no provoca reacciones de inflamación o antigénicas, fácil modelado y fuerza de compresión semejante al tejido óseo. Todas éstas características son necesarias...

  19. STUDY OF CRYSTALLIZATION OF CALCIUM SULFATE DIHYDRATE THAT HAS POLYMER ADDITIVES

    Directory of Open Access Journals (Sweden)

    Ustinova Yuliya Valer'evna

    2012-10-01

    A. It is identified that additives based on polymers of different origin affect processes of crystallization, the size and shape of crystals. B. The X-ray diffraction analysis has proven that molecules of polymer additives do not penetrate into the gypsum structure and the chemical composition of the product does not change. C. Methods of thermal analysis have proven that the introduction of polymer additives does not produce any adverse impact on the stability of gypsum crystals, if exposed to temperature fluctuations. D. The major impact produced onto crystallization is the one of the super plasticizer based on the sulfonated melamine-formaldehyde resin.

  20. Individual and combined effects of chloride, sulfate, and magnesium ions on hydrated Portland-cement paste

    International Nuclear Information System (INIS)

    Ground water with a high concentration of magnesium ion is known to cause deterioration to portland cement concretes. A proposed mechanism for this deterioration process published previously involves an approximate 1:1 replacement of Ca ions by Mg ions in the crystalline phases of hydrated cement. The current study was undertaken to determine which ions, among magnesium, chloride, and sulfate, cause deterioration; whether their deleterious action is individual or interdependent; and to relate this mechanism of deterioration to the outlook for a 100-yr service life of concretes used in mass placements at the Waste Isolation Pilot Plant. Loss of Ca ion by cement pastes was found to be strongly related to the concentration of Mg ion in simulated ground-water solutions in which the paste samples were aged. This was true of both salt- containing and conventional cement pastes. No other ion in the solutions exerted a strong effect on Ca loss. Ca ion left first from calcium hydroxide in the pastes, depleting all calcium hydroxide by 60 days. Some calcium silicate hydrate remained even after 90 days in the solutions with the highest concentration of Mg ion, while the paste samples deteriorated noticeably. The results indicated a mechanism that involves dissolution of Ca phases and transport of Ca ions to the surface of the sample, followed by formation of Mg-bearing phases at this reaction surface rather than directly by substitution within the microstructure of hydrated cement. Given that calcium hydroxide and calcium silicate hydrate are the principal strength-giving phases of hydrated cement, this mechanism indicates the likelihood of significant loss of integrity of a concrete exposed to Mg-bearing ground water at the WIPP. The rate of deterioration ultimately will depend on Mg-ion concentration, the microstructure materials of the concrete exposed to that groundwater, and the availability of brine

  1. Calcium binding protein-mediated regulation of voltage-gated calcium channels linked to human diseases

    Institute of Scientific and Technical Information of China (English)

    Nasrin NFJATBAKHSH; Zhong-ping FENG

    2011-01-01

    Calcium ion entry through voltage-gated calcium channels is essential for cellular signalling in a wide variety of cells and multiple physiological processes. Perturbations of voltage-gated calcium channel function can lead to pathophysiological consequences. Calcium binding proteins serve as calcium sensors and regulate the calcium channel properties via feedback mechanisms. This review highlights the current evidences of calcium binding protein-mediated channel regulation in human diseases.

  2. Bone sialoprotein keratan sulfate proteoglycan (BSP-KSPG) and FGF-23 are important physiological components of medullary bone.

    Science.gov (United States)

    Hadley, Jill A; Horvat-Gordon, Maria; Kim, Woo-Kyun; Praul, Craig A; Burns, Dennis; Leach, Roland M

    2016-04-01

    Medullary bone is a specialized bone found in the marrow cavity of laying birds. It provides a significant contribution to the calcium supply for egg shell formation. Medullary bone is distinguished from cortical bone by the presence of large amounts of a keratan sulfate proteoglycan (KSPG). The aims of the present experiment are to confirm the identity of the core protein of KSPG, identify a marker of medullary bone metabolism, and determine whether changes in keratan sulfate (KS) concentration in blood are associated with the egg-laying cycle. Using two different isolation techniques- one specific for bone and another for blood- we have identified bone sialoprotein (BSP) to be the core protein of this KSPG. We also determined that the amount of keratan sulfate (KS) in laying hen blood fluctuates in synchrony with the egg-laying cycle, and thus can serve as a specific marker for medullary bone metabolism. During the course of this investigation, we also found FGF-23 (phosphatonin) to be expressed in medullary bone, in synchrony with the egg-laying cycle. Western blotting was used to demonstrate the presence of this peptide in both laying hen blood and medullary bone extracts. The importance of FGF-23 (phosphatonin) and parathyroid hormone in normalizing the dramatic changes in plasma calcium and phosphorus during the 24h egg-laying cycle is discussed. PMID:26773479

  3. Intravenous magnesium sulfate therapy in severe asthma

    Directory of Open Access Journals (Sweden)

    Mohd. Al-Ajmi

    2007-01-01

    Full Text Available A 22-year-old female, known asthmatic since seven years, developed severe bronchospasm in the preop-erative period. Bronchospasm remained unresponsive to the inhaled beta-agonist plus anticholinergic, IV ami-nophylline and hydrocortisone but responded quickly with magnesium sulfate® ( PSI, KSA infusion 1.25gm in 100ml normal saline over 20 minutes and another 1.25 gm over next 30 minutes as the initial infusion showed improvement in her clinical symptoms. Within half an hour of administering the 1st infusion of magnesium sulfate (1.25 gm the respiratory rate started reducing, rhonchi became less, SpO 2 came upto 92% and re-mained always above 90%. Encouraged by this result IV magnesium sulfate 2.5 gm in 500 ml normal saline was infused over next 24 hours along with alternate salbutamol and ipratropium nebulization every 6 hourly. With this treatment regimen the patient became asymptomatic within next 24 hours with normal clinical parameters and FEV 1 value. Hence it may be concluded that IV magnesium sulfate can be considered for patients with acute severe asthma who do not respond to standard therapeutic medications.

  4. Synthesis and Characterization of Nanostructured Sulfated Zirconias

    Czech Academy of Sciences Publication Activity Database

    Lutecki, M.; Šolcová, Olga; Werner, S.; Breitkopf, C.

    2010-01-01

    Roč. 53, č. 1 (2010), s. 13-20. ISSN 0928-0707 Grant ostatní: DFG(DE) BR2068/2-1; DFG(DE) BR2068/2-2 Institutional research plan: CEZ:AV0Z40720504 Keywords : sulfated zirconia * template assisted synthesis * porous materials Subject RIV: CA - Inorganic Chemistry Impact factor: 1.525, year: 2010

  5. Sulfate-reducing bacteria in anaerobic bioreactors.

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.

    1998-01-01

    The treatment of industrial wastewaters containing high amounts of easily degradable organic compounds in anaerobic bioreactors is a well-established process. Similarly, wastewaters which in addition to organic compounds also contain sulfate can be treated in this way. For a long time, the occurrenc

  6. Radioprotective properties of the polysaccharide dextran sulfate

    International Nuclear Information System (INIS)

    Experiments have been conducted on mice-hydrides (SFUxS57BI)F1. Dextran sulfate (mol. w. 500000) has been injected once intraperitoneally at the dose of 60 mg/ml before exposure. The following conclusions are made: 1) highly molecular dextran sulfate injected during 1-3 days before exposure of mice at lethal doses of 9.57, 9 and 15.86 Gr at the corresponding dose rates of 8x10-3, 3x10-3 and 8x10-4 Gr/s increases radioresistance of animals increasing their 30 day survival up to 45-70%; 2) when injecting dextran sulfate a day before exposure increase of the organism radioresistance is followed by acceleration of postradiation restoration of the number of blood leukocytes, nucleus hearing cells of bone marrow and mass of spleen; 3) dextrain sulfate injected 3 days before irradiation does not produce any effect on expressiveness of postradiation leukopenia and bone marrow cytopenia

  7. Sulfate reduction and methanogenesis at a freshwater

    DEFF Research Database (Denmark)

    Iversen, Vibeke Margrethe Nyvang; Andersen, Martin Søgaard; Jakobsen, Rasmus

    enriched in dissolved sulfide, methane and bicarbonate. Under normal conditions the seawater-freshwater interface is found at a depth of 4 m at the coastline and reaches the bottom of the aquifer 40 m inland. However, occasional flooding of the area occurs, introducing sulfate to the aquifer. Groundwater...

  8. Determination of boron spectrophotometry in thorium sulfate

    International Nuclear Information System (INIS)

    A procedure for the determination of microquantities of boron in nuclear grade thorium sulfate is described. The method is based on the extraction of BF-4 ion associated to monomethylthionine (MMT) in 1,2 - dichloroethane. The extraction of the colored BF-4-MMT complex does not allow the presence of sulfuric and phosphoric acids; other anions interfere seriously. This fact makes the dissolution of the thorium sulfate impracticable, since it is insoluble in both acids. On the other hand, the quantitative separation of thorium is mandatory, to avoid the precipitation of ThF4. To overcome this difficulty, the thorium sulfate is dissolved using a strong cationic ion exchanger, Th4+ being totally retained into the resin. Boron is then analysed in the effluent. The procedure allows the determination of 0.2 to 10.0 microgramas of B, with a maximum error of 10%. Thorium sulfate samples with contents of 0.2 to 2.0μg B/gTh have being analysed

  9. 21 CFR 184.1143 - Ammonium sulfate.

    Science.gov (United States)

    2010-04-01

    ... the specifications of the “Food Chemicals Codex,” 3d Ed. (1981), pp. 22-23, which is incorporated by... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ammonium sulfate. 184.1143 Section 184.1143 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  10. 21 CFR 184.1643 - Potassium sulfate.

    Science.gov (United States)

    2010-04-01

    ... hydroxide or potassium carbonate. (b) The ingredient meets the specifications of the “Food Chemicals Codex... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium sulfate. 184.1643 Section 184.1643 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

  11. Scientific Opinion on the safety assessment of the active substances, sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulphate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water, for use as active system in food contact materials

    Directory of Open Access Journals (Sweden)

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

    2014-02-01

    Full Text Available This scientific opinion of EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids deals with the safety assessment of the active substances sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulfate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water, used in mixture which is packed into sachets for absorbing oxygen/carbon dioxide emitting from/into the headspace surrounding packed food. All substances of this formulation have been evaluated and approved for use as additives in plastic food contact materials or as food additives. No migration of calcium, iron and sodium ions was detected. No volatile organic compounds other than carbon dioxide were detected at the limit of detection of 0.5 μg/l. The CEF Panel concluded that the use of the substances sodium erythorbate, sodium carbonate, sodium bicarbonate, iron sulfate, activated carbon, cellulose, calcium hydroxide, calcium chloride and water does not raise a safety concern when used in oxygen absorber/carbon dioxide emitter systems, in sachets that prevent the physical release of their contents into the food. The sachets are to be placed in the headspace of the packaging and as such may come into occasional contact with the food, e.g. during handling. The sachet should not come into direct contact with liquid foods or foods that have and external aqueous liquid phase on the surface (liquid or exudates.

  12. Comprehensive sulfation model verified for T-T sorbent clusters during flue gas desulfurization at moderate temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Yuran Li; Haiying Qi; Changfu You; Lizhai Yang [Tsinghua University, Beijing (China). Key Laboratory for Thermal Science and Power Engineering of Ministry of Education

    2010-08-15

    An empirical sulfation model for T-T sorbent clusters was developed based on amassed experimental results under moderate temperatures (300-800{sup o}C). In the model, the reaction rate is a function of clusters mass, SO{sub 2} concentration, CO{sub 2} concentration, calcium conversion and temperature. The smaller pore volume partly results in a lower reaction rate at lower temperatures. The exponent on SO{sub 2} concentration is 0.88 in the rapid reaction stage and then decreases gradually as reaction progresses. The exponent on the fraction of the unreacted calcium is 1/3 in the first stage and then increases significantly in the second stage. The CO{sub 2} concentration has a negative influence on SO{sub 2} removal, especially for the temperature range of 400-650{sup o}C, which should be avoided to achieve a high effective calcium conversion. The sulfation model has been verified for the T-T sorbent clusters and has also been applied to CaO particles. Over extensive reaction conditions, the predictions agree well with experimental data. 17 refs., 10 figs., 2 tabs.

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

    OpenAIRE

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

    2015-01-01

    At the frog neuromuscular junction, under physiological conditions, the direct measurement of calcium currents and of the concentration of intracellular calcium buffers—which determine the kinetics of calcium concentration and neurotransmitter release from the nerve terminal—has hitherto been technically impossible. With the aim of quantifying both Ca2+ currents and the intracellular calcium buffers, we measured fluorescence signals from nerve terminals loaded with the low-affinity calcium dy...

  14. Influence of the Ca/Si ratio of the C–S–H phase on the interaction with sulfate ions and its impact on the ettringite crystallization pressure

    International Nuclear Information System (INIS)

    The effect of the Ca/Si ratio of the calcium–silicate–hydrate (C–S–H) phase on the interaction with sulfate ions is investigated for C–S–H phases (Ca/Si = 0.83, 1.25, 1.50) and mortar samples of blended Portland cements. It is shown that leaching of calcium from C–S–H and portlandite affects the composition of the pore solution and contributes to the developing crystallization pressure of ettringite. Sulfate profiles show that sulfate binding before cracking is similar for different Ca/Si ratios whereas the highest expansion rates are observed for the mortars with the highest Ca/Si ratios. After leaching in sulfate solutions, the C–S–H samples have been characterized by 29Si MAS NMR, thermogravimetric analysis, and elemental solution analysis. Generally, the exposure to sulfate solutions results in decalcification of the C–S–H, which increases with decreasing Ca/Si ratio. The data are in good agreement with thermodynamic modeling, indicating that equilibrium is almost achieved in the leached systems. Finally, the expansion of mortar samples exposed to sulfate solutions was much less at lower Ca/Si ratios of the cement blends. This reduced expansion can be related to the decrease of the supersaturation of the pore solution with respect to ettringite at lower Ca/Si ratios of the C–S–H and in the absence of portlandite

  15. Influence of the Ca/Si ratio of the C–S–H phase on the interaction with sulfate ions and its impact on the ettringite crystallization pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kunther, Wolfgang [Instrument Centre for Solid-State NMR Spectroscopy, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); Lothenbach, Barbara [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Concrete/Construction Chemistry, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Skibsted, Jørgen, E-mail: jskib@chem.au.dk [Instrument Centre for Solid-State NMR Spectroscopy, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark)

    2015-03-15

    The effect of the Ca/Si ratio of the calcium–silicate–hydrate (C–S–H) phase on the interaction with sulfate ions is investigated for C–S–H phases (Ca/Si = 0.83, 1.25, 1.50) and mortar samples of blended Portland cements. It is shown that leaching of calcium from C–S–H and portlandite affects the composition of the pore solution and contributes to the developing crystallization pressure of ettringite. Sulfate profiles show that sulfate binding before cracking is similar for different Ca/Si ratios whereas the highest expansion rates are observed for the mortars with the highest Ca/Si ratios. After leaching in sulfate solutions, the C–S–H samples have been characterized by {sup 29}Si MAS NMR, thermogravimetric analysis, and elemental solution analysis. Generally, the exposure to sulfate solutions results in decalcification of the C–S–H, which increases with decreasing Ca/Si ratio. The data are in good agreement with thermodynamic modeling, indicating that equilibrium is almost achieved in the leached systems. Finally, the expansion of mortar samples exposed to sulfate solutions was much less at lower Ca/Si ratios of the cement blends. This reduced expansion can be related to the decrease of the supersaturation of the pore solution with respect to ettringite at lower Ca/Si ratios of the C–S–H and in the absence of portlandite.

  16. Variability of calcium absorption

    International Nuclear Information System (INIS)

    Variability in calcium absorption was estimated in three groups of normal subjects in whom Ca absorption was measured by standard isotopic-tracer methods at interstudy intervals ranging from 1 to 4 mo. Fifty absorption tests were performed in 22 subjects. Each was done in the morning after an overnight fast with an identical standard breakfast containing a Ca load of approximately 250 mg. Individual fractional absorption values were normalized to permit pooling of the data. The coefficient of variation (CVs) for absorption for the three groups ranged from 10.57 to 12.79% with the size of the CV increasing with interstudy duration. One other published study presenting replicate absorption values was analyzed in a similar fashion and was found to have a CV of absorption of 9.78%. From these data we estimate that when the standard double-isotope method is used to measure Ca absorption there is approximately 10% variability around any given absorption value within an individual human subject and that roughly two-thirds of this represents real biological variability in absorption

  17. An efficient calcium phosphate nanoparticle-based nonviral vector for gene delivery

    Directory of Open Access Journals (Sweden)

    Liu YC

    2011-04-01

    Full Text Available Yachun Liu1,2,*, Tao Wang1,*, Fangli He1,*, Qian Liu1,*, Dexi Zhang2, Shuanglin Xiang1, Shengpei Su2, Jian Zhang11Key Laboratory of Protein Chemistry and Developmental Biology, Ministry of Education of China, College of Life Sciences; 2Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research and Key Laboratory of Sustainable Resources Processing and Advanced Materials of Hunan Province, Ministry of Education of China, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, China*These authors contributed equally to this workBackground: Smaller nanoparticles facilitate the delivery of DNA into cells through endocytosis and improve transfection efficiency. The aim of this study was to determine whether protamine sulfate-coated calcium phosphate (PS-CaP could stabilize particle size and enhance transfection efficiency.Methods: pEGFP-C1 green fluorescence protein was employed as an indicator of transfection efficiency. Atomic force microscopy was used to evaluate the morphology and the size of the particles, and an MTT assay was introduced to detect cell viability and inhibition. The classical calcium phosphate method was used as the control.Results: Atomic force microscopy images showed that the PS-CaP were much smaller than classical calcium phosphate particles. In 293 FT, HEK 293, and NIH 3T3 cells, the transfection efficiency of PS-CaP was higher than for the classical calcium phosphate particles. The difference in efficiencies implies that the smaller nanoparticles may promote the delivery of DNA into cells through endocytosis and could improve transfection efficiency. In addition, PS-CaP could be used to transfect HEK 293 cells after one week of storage at 4°C with a lesser extent of efficiency loss compared with classical calcium phosphate, indicating that protamine sulfate may increase the stability of calcium phosphate nanoparticles. The cell viability inhibition assay indicated that

  18. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sodium sulfate. 582.1131 Section 582.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  19. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sodium sulfate. 182.1131 Section 182.1131 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD... Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  20. Water absorbance and thermal properties of sulfated wheat gluten films

    Science.gov (United States)

    Wheat gluten films of varying thicknesses formed at 30C to 70C were treated with cold sulfuric acid to produce sulfated gluten films. Chemical, thermal, thermal stability, and water uptake properties were characterized for neat and sulfated films. The sulfated gluten films were able ...

  1. Calcium-sensitive immunoaffinity chromatography

    DEFF Research Database (Denmark)

    Henriksen, Maiken L; Lindhardt Madsen, Kirstine; Skjoedt, Karsten;

    2014-01-01

    homogeneity may be impossible due to contamination with abundant antigens. In this study, we purified the scarce, complement-associated plasma protein complex, collectin LK (CL-LK, complex of collectin liver 1 and kidney 1), by immunoaffinity chromatography using a calcium-sensitive anti-collectin-kidney-1 m......Ab. This antibody was characterized by binding to CL-LK at hypo- and physiological calcium concentrations and dissociated from CK-LK at hyperphysiological concentrations of calcium. We purified CL-LK from plasma to a purity of 41% and a yield of 38%, resulting in a purification factor of more than 88......,000 in a single step. To evaluate the efficiency of this new purification scheme, we purified CL-LK using the same calcium-sensitive mAb in combination with acidic elution buffer and by using calcium-dependent anti-CL-K1 mAbs in combination with EDTA elution buffer. We found that calcium...

  2. Acid Sulfate Alteration in Gusev Crater, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Catalano, J. G.

    2016-01-01

    The Mars Exploration Rover (MER) Spirit landed on the Gusev Crater plains west of the Columbia Hills in January, 2004, during the Martian summer (sol 0; sol = 1 Martian day = 24 hr 40 min). Spirit explored the Columbia Hills of Gusev Crater in the vicinity of Home Plate at the onset on its second winter (sol approximately 900) until the onset of its fourth winter (sol approximately 2170). At that time, Spirit became mired in a deposit of fined-grained and sulfate-rich soil with dust-covered solar panels and unfavorable pointing of the solar arrays toward the sun. Spirit has not communicated with the Earth since sol 2210 (January, 2011). Like its twin rover Opportunity, which landed on the opposite side of Mars at Meridiani Planum, Spirit has an Alpha Particle X-Ray Spectrometer (APXS) instrument for chemical analyses and a Moessbauer spectrometer (MB) for measurement of iron redox state, mineralogical speciation, and quantitative distribution among oxidation (Fe(3+)/sigma Fe) and coordination (octahedral versus tetrahedral) states and mineralogical speciation (e.g., olivine, pyroxene, ilmenite, carbonate, and sulfate). The concentration of SO3 in Gusev rocks and soils varies from approximately 1 to approximately 34 wt%. Because the APXS instrument does not detect low atomic number elements (e.g., H and C), major-element oxide concentrations are normalized to sum to 100 wt%, i.e., contributions of H2O, CO2, NO2, etc. to the bulk composition care not considered. The majority of Gusev samples have approximately 6 plus or minus 5 wt% SO3, but there is a group of samples with high SO3 concentrations (approximately 30 wt%) and high total iron concentrations (approximately 20 wt%). There is also a group with low total Fe and SO3 concentrations that is also characterized by high SiO2 concentrations (greater than 70 wt%). The trend labeled "Basaltic Soil" is interpreted as mixtures in variable proportions between unaltered igneous material and oxidized and SO3-rich basaltic

  3. Rapid regional recovery from sulfate and nitrate pollution in streams of the western Czech Republic - Comparison to other recovering areas

    Science.gov (United States)

    Majer, V.; Kram, P.; Shanley, J.B.

    2005-01-01

    Hydrochemical changes between 1991 and 2001 were assessed based on two synoptic stream surveys from the 820-km2 region of the Slavkov Forest and surrounding area, western Czech Republic. Marked declines of sulfate, nitrate, chloride, calcium and magnesium in surface waters were compared with other areas of Europe and North America recovering from acidification. Declines of sulfate concentration in the Slavkov Forest (-30 ??eq L-1 yr-1) were more dramatic than declines reported from other sites. However, these dramatic declines of strong acid anions did not generate a widespread increase of stream water pH in the Slavkov Forest. Only the most acidic streams experienced a slight increase of pH by 0.5 unit. An unexpected decline of stream water pH occurred in slightly alkaline streams. ?? 2004 Elsevier Ltd. All rights reserved.

  4. 21 CFR 524.155 - Bacitracin zinc-polymyxin B sulfate-neomycin sulfate-hydrocortisone or hydrocortisone acetate...

    Science.gov (United States)

    2010-04-01

    ... sulfate-hydrocortisone or hydrocortisone acetate ophthalmic ointment. 524.155 Section 524.155 Food and... zinc-polymyxin B sulfate-neomycin sulfate-hydrocortisone or hydrocortisone acetate ophthalmic ointment... 10 milligrams of hydrocortisone acetate. (b) Conditions of use. Dogs and cats—(1) Amount. Apply...

  5. Utilization of sulfate additives in biomass combustion: fundamental and modeling aspects

    OpenAIRE

    Wu, Hao; Jespersen, Jacob Boll; Grell, Morten Nedergaard; Aho, Martti; Jappe Frandsen, Flemming; Glarborg, Peter

    2013-01-01

    Sulfates, such as ammonium sulfate, aluminum sulfate and ferric sulfate, are effective additives for converting the alkali chlorides released from biomass combustion to the less harmful alkali sulfates. Optimization of the use of these additives requires knowledge on their decomposition rate and product distribution under high temperature conditions. In the present work, the decomposition of ammonium sulfate, aluminum sulfate and ferric sulfate wasstudied respectively in a fast-heating rate t...

  6. "Caged calcium" in Aplysia pacemaker neurons. Characterization of calcium-activated potassium and nonspecific cation currents

    OpenAIRE

    1989-01-01

    We have studied calcium-activated potassium current, IK(Ca), and calcium-activated nonspecific cation current, INS(Ca), in Aplysia bursting pacemaker neurons, using photolysis of a calcium chelator (nitr-5 or nitr-7) to release "caged calcium" intracellularly. A computer model of nitr photolysis, multiple buffer equilibration, and active calcium extrusion was developed to predict volume-average and front-surface calcium concentration transients. Changes in arsenazo III absorbance were used to...

  7. ELECTRON DETACHMENT DISSOCIATION OF DERMATAN SULFATE OLIGOSACCHARIDES

    OpenAIRE

    Wolff, Jeremy J.; Laremore, Tatiana N.; BUSCH, ALEXANDER M.; Linhardt, Robert J.; Amster, I. Jonathan

    2007-01-01

    The structural characterization of glycosaminoglycans (GAG) oligosaccharides has been a longstanding challenge in the field of mass spectrometry. In this work, we present the application of electron detachment dissociation (EDD) Fourier transform mass spectrometry to the analysis of dermatan sulfate (DS) oligosaccharides up to 10 residues in length. The EDD mass spectra of DS oligosaccharides were compared to their infrared multiphoton dissociation (IRMPD) mass spectra. EDD produces more abun...

  8. Structum (chondroitin sulfate) in treatment of osteoarthritis

    OpenAIRE

    O J Varga; V K Ignatjev; N N Vesikova; I M Marusenko

    2003-01-01

    Objective. To assess Structum (chondroitin sulfate) efficacy in treatment of osteoarthritis in Republic of Karelia. Methods. 34 pts with osteoarthritis (mean disease duration 6,44±0,67 years) were included. Functional Leken score (FLS), pain at rest and at walk on visual analog scale (VAS), pts nonsteroidal anti-inflammatory drugs (NSAID) requirement (diclofenac daily requirement in mg), percent of pts refused NSAID treatment, achievement of clinically significant improvement (40% decrease of...

  9. Effect of Preharvest Calcium Treatments on Sweet Cherry Fruit Quality

    OpenAIRE

    Deniz EROGUL

    2014-01-01

    In this study, the effects of different foliar calcium compounds on fruit cracking and quality of sweet cherry variety ‘0900 Ziraat’ were investigated. Calcium caseinate, calcium chloride, calcium hydroxide and calcium nitrate were used as foliar sprays. Calcium applications reduced the cracking index 38% to 66% compared to cherries that did not receive foliar treatment. The most efficient applications for decreasing cracking were calcium hydroxide and calcium chloride. Calcium chloride and c...

  10. Stochastic Simulation of Cardiac Ventricular Myocyte Calcium Dynamics and Waves

    OpenAIRE

    Tuan, Hoang-Trong Minh; Williams, George S.B.; Chikando, Aristide C.; Sobie, Eric A.; Lederer, W. Jonathan; Jafri, M. Saleet

    2011-01-01

    A three dimensional model of calcium dynamics in the rat ventricular myocyte was developed to study the mechanism of calcium homeostasis and pathological calcium dynamics during calcium overload. The model contains 20,000 calcium release units (CRUs) each containing 49 ryanodine receptors. The model simulates calcium sparks with a realistic spontaneous calcium spark rate. It suggests that in addition to the calcium spark-based leak, there is an invisible calcium leak caused by the stochastic ...

  11. Effects of sulfate chitosan derivatives on nonalcoholic fatty liver disease

    Science.gov (United States)

    Yu, Mingming; Wang, Yuanhong; Jiang, Tingfu; Lv, Zhihua

    2014-06-01

    Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.

  12. Structure and anticoagulant properties of sulfated glycosaminoglycans from primitive Chordates

    Directory of Open Access Journals (Sweden)

    PAVÃO MAURO S. G.

    2002-01-01

    Full Text Available Dermatan sulfates and heparin, similar to the mammalian glycosaminoglycans, but with differences in the degree and position of sulfation were previously isolated from the body of the ascidian Styela plicata and Ascidia nigra. These differences produce profound effects on their anticoagulant properties. S. plicata dermatan sulfate composed by 2-O-sulfatedalpha-L-iduronic acid and 4-O-sulfated N-acetyl-beta-D-galactosamine residues is a potent anticoagulant due to a high heparin cofactor II activity. Surprisingly, it has a lower potency to prevent thrombus formation on an experimental model and a lower bleeding effect in rats than the mammalian dermatan sulfate. In contrast, A. nigra dermatan sulfate, also enriched in 2-O-sulfated alpha-L-iduronic acid, but in this case sulfated at O-6 of the N-acetyl-beta-D-galactosamine units, has no in vitro or in vivo anticoagulant activity, does not prevent thrombus formation but shows a bleeding effect similar to the mammalian glycosaminoglycan. Ascidian heparin, composed by 2-O-sulfated alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (75% and alpha-L-iduronic acid, N- and 6-O-sulfated glucosamine (25% disaccharide units has an anticoagulant activity 10 times lower than the mammalian heparin, is about 20 times less potent in the inhibition of thrombin by antithrombin, but has the same heparin cofactor II activity as mammalian heparin.

  13. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...

  14. Concrete Deterioration under Alternate Action of Carbonation and Sulfate Attack

    Directory of Open Access Journals (Sweden)

    Fenglan Li

    2013-11-01

    Full Text Available By micro- and macro-observations, the study reveals the deterioration mechanisms of concrete under alternate action of carbonation and sodium sulfate solution attack (C-SA comparied with the single sodium sulfate solution attack (SA. The studies indicate that in both cases, the main attack product is ettringite, some gypsum is checked only in the first layer of case SA, the thaumasite form of sulfate attack is not initiated in case C-SA. Compared with the single sodium sulfate solution attack, although the carbonation layer mitigates the extent of sulfate attack in limited exposure period, the alternate action of carbonation and sulfate attack still leads to strength degradation to some extent. The effect of carbonation on sulfate attack for longer exposure period deserves further research.

  15. Adsorption of sulfate in PWR steam generators: Laboratory tests

    International Nuclear Information System (INIS)

    Following observation of an apparent difference in the hideout mechanism for sulfate compared to that of other highly soluble species during chemical injection tests at several PWRS, a laboratory test program, discussed in this report was implemented to quantify sulfate adsorption on metal surfaces. Approximately 350 ug/m2 of sulfate could be adsorbed on Alloy 600 from neutral solutions at 300 degree C. Less adsorption was observed at lower temperature as well as at increased pH. The adsorbed sulfate could be desorbed into pure water over a period of several days subsequent to termination of sulfate ingress. Thus, a prompt shutdown to hot standby with maximization of blowdown should minimize the long term impact of sulfate steam generator corrosion subsequent to a period of significant sulfate or cation resin ingress. The only other species which exhibited significant adsorption was phosphate which also has a tetrahedral ionic structure in solution

  16. Sulfate reduction and anaerobic methane oxidation in Black Sea sediments

    DEFF Research Database (Denmark)

    Jørgensen, BB; Weber, A.; Zopfi, J.

    2001-01-01

    Beyond the shelf break at ca. 150 m water depth, sulfate reduction is the only important process of organic matter oxidation in Black Sea sediments from the surface down to the sulfate-methane transition at 2-4 m depth. Sulfate reduction rates were measured experimentally with (SO42-)-S-35, and the...... the process was very sluggish with turnover times of methane within the sulfate-methane transition zone of 20 yr or more. (C) 2001 Elsevier Science Ltd. All rights reserved.Beyond the shelf break at ca. 150 m water depth, sulfate reduction is the only important process of organic matter oxidation in...... Black Sea sediments from the surface down to the sulfate-methane transition at 2-4 m depth. Sulfate reduction rates were measured experimentally with (SO42-)-S-35, and the rates were compared with results of two diffusion-reaction models. The results showed that, even in these non-bioirrigated sediments...

  17. Aging and calcium as an environmental factor.

    Science.gov (United States)

    Fujita, T

    1985-12-01

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

  18. Transport of Calcium Ions into Mitochondria.

    Science.gov (United States)

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

    2016-06-01

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

  19. Regional transport model of atmospheric sulfates

    International Nuclear Information System (INIS)

    As part of the Sulfate Regional Experiment (SURE) Design Project, a regional transport model of atmospheric sulfates has been developed. This quasi-Lagrangian three-dimensional grid numerical model uses a detailed SO2 emission inventory of major anthropogenic sources in the Eastern U.S. region, and observed meteorological data during an episode as inputs. The model accounts for advective transport and turbulent diffusion of the pollutants. The chemical transformation of SO2 and SO4/sup =/ and the deposition of the species at the earth's surface are assumed to be linear processes at specified constant rates. The numerical model can predict the daily average concentrations of SO2 and SO4/sup =/ at all receptor locations in the grid region during the episode. Because of the spatial resolution of the grid, this model is particularly suited to investigate the effect of tall stacks in reducing the ambient concentration levels of sulfur pollutants. This paper presents the formulations and assumptions of the regional sulfate transport model. The model inputs and results are discussed. Isopleths of predicted SO2 and SO4/sup =/ concentrations are compared with the observed ground level values. The bulk of the information in this paper is directed to air pollution meteorologists and environmental engineers interested in the atmospheric transport modeling studies of sulfur oxide pollutants

  20. Modeling of calcium-based sorbent reactions with sulfur dioxide

    Directory of Open Access Journals (Sweden)

    Tomanović Ivan

    2015-01-01

    Full Text Available A mathematical model of calcium sorbent reactions for simulation of sulfur dioxide reduction from pulverized coal combustion fl e gasses is developed, implemented within numerical code and validated against available measurements under controlled conditions. The model attempts to closely resemble reactions of calcination, sintering and sulfation, occurring during the sorbent particles motion in the furnace. The sulfation is based on PSSM (Partially Sintered Spheres Model, coupled with simulated particle calcination and sintering. Complex geometry of the particle is taken into account, with the assumption that it consists of spherical grains in contact with each other. Numerical simulations of drop down tube reactors were performed for both CaCO3 and Ca(OH2 sorbent particles and results were compared with available experimental data from literature. The sorbent reactions model will be further used for simulations of desulfurization reactions in turbulent gas-particle flow under coalcombustion conditions. [Projekat Ministarstva nauke Republike Srbije, br. TR-33018: Increase in energy and ecology efficiency of processes in pulverized coal-fired furnace and optimization of utility steam boiler air preheater by using in-house developed software tools

  1. Optimizing calcium selective fluorimetric nanospheres.

    Science.gov (United States)

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

    2015-11-01

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

  2. Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

    International Nuclear Information System (INIS)

    By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca9Sr(PO4)6(OH)2 - CaSr9(PO4)6(OH)2. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

  3. Structural characterization of anion-calcium-humate complexes in phosphate-based fertilizers.

    Science.gov (United States)

    Baigorri, Roberto; Urrutia, Oscar; Erro, Javier; Mandado, Marcos; Pérez-Juste, Ignacio; Garcia-Mina, José María

    2013-07-01

    Fertilizers based on phosphate-metal-humate complexes are a new family of compounds that represents a more sustainable and bioavailable phosphorus source. The characterization of this type of complex by using solid (31)P NMR in several fertilizers, based on single superphosphate (SSP) and triple superphosphate (TSP) matrices, yielded surprising and unexpected trends in the intensity and fine structure of the (31)P NMR peaks. Computational chemistry methods allowed the characterization of phosphate-calcium-humate complexes in both SSP and TSP matrices, but also predicted the formation of a stable sulfate-calcium-humate complex in the SSP fertilizers, which has not been described previously. The stability of this complex has been confirmed by using ultrafiltration techniques. Preference towards the humic substance for the sulfate-metal phase in SSP allowed the explanation of the opposing trends that were observed in the experimental (31)P NMR spectra of SSP and TSP samples. Additionally, computational chemistry has provided an assignment of the (31)P NMR signals to different phosphate ligands as well as valuable information about the relative strength of the phosphate-calcium interactions within the crystals. PMID:23670945

  4. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Ueda, Yukari; Taira, Zenei

    2013-01-01

    We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intes...

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

    Science.gov (United States)

    Hoth, M; Penner, R

    1993-06-01

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

  6. Calcium phosphate in catheter encrustation.

    Science.gov (United States)

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

    1987-02-01

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

  7. Heritability and clinical determinants of serum indoxyl sulfate and p-cresyl sulfate, candidate biomarkers of the human microbiome enterotype.

    Directory of Open Access Journals (Sweden)

    Liesbeth Viaene

    Full Text Available BACKGROUND: Indoxyl sulfate and p-cresyl sulfate are unique microbial co-metabolites. Both co-metabolites have been involved in the pathogenesis of accelerated cardiovascular disease and renal disease progression. Available evidence suggests that indoxyl sulfate and p-cresyl sulfate may be considered candidate biomarkers of the human enterotype and may help to explain the link between diet and cardiovascular disease burden. OBJECTIVE AND DESIGN: Information on clinical determinants and heritability of indoxyl sulfate and p-cresyl sulfate serum is non-existing. To clarify this issue, the authors determined serum levels of indoxyl sulfate and p-cresyl sulfate in 773 individuals, recruited in the frame of the Flemish Study on Environment, Genes and Health Outcomes (FLEMENGHO study. RESULTS: Serum levels of indoxyl sulfate and p-cresyl sulfate amounted to 3.1 (2.4-4.3 and 13.0 (7.4-21.5 μM, respectively. Regression analysis identified renal function, age and sex as independent determinants of both co-metabolites. Both serum indoxyl sulfate (h2 = 0.17 and p-cresyl sulfate (h2 = 0.18 concentrations showed moderate but significant heritability after adjustment for covariables, with significant genetic and environmental correlations for both co-metabolites. LIMITATIONS: Family studies cannot provide conclusive evidence for a genetic contribution, as confounding by shared environmental effects can never be excluded. CONCLUSIONS: The heritability of indoxyl sulfate and p-cresyl sulfate is moderate. Besides genetic host factors and environmental factors, also renal function, sex and age influence the serum levels of these co-metabolites.

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

    Science.gov (United States)

    Chu, J.

    1971-01-01

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

  9. Sulfation pattern of fucose branches affects the anti-hyperlipidemic activities of fucosylated chondroitin sulfate.

    Science.gov (United States)

    Wu, Nian; Zhang, Yu; Ye, Xingqian; Hu, Yaqin; Ding, Tian; Chen, Shiguo

    2016-08-20

    Fucosylated chondroitin sulfates (fCSs) are glycosaminoglycans extracted from sea cucumbers, consisting of chondroitin sulfate E (CSE) backbones and sulfated fucose branches. The biological properties of fCSs could be affected by the sulfation pattern of their fucose branches. In the present study, two fCSs were isolated from sea cucumbers Isostichopus badionotus (fCS-Ib) and Pearsonothuria graeffei (fCS-Pg). Their monosaccharide compositions of glucuronic acid (GlcA), N-acetylgalactosamine (GalNAc), fucose (Fuc) and sulfate were at similar molar ratio with 1.0/0.7/0.9/3.1 for fCS-Ib and 1.0/0.8/1.5/2.6 for fCS-Pg. The two fCSs have different sulfation patterns on their fucose branches, fCS-Pg with 3,4-O-disulfation while fCS-Ib with 2,4-O-disulfation. Their antihyperlipidemic effects were compared using a high-fat high-fructose diet (HFFD)-fed C57BL/6J mice model. Both fCS-Ib and fCS-Pg had significant effects on lipid profile improvement, liver protection, blood glucose diminution and hepatic glycogen synthesis. Specifically, fCS-Pg with 3,4-O-disulfation fucose branches was more effective in reduction of blood cholesterol (TC), low density lipoprotein (LDL) and atherogenic index (AI). Our results indicate that both fCSs, especially fCS-Pg, could be used as a potential anti-hyperlipidemic drug. PMID:27178902

  10. Tumoral calcium pyrophosphate deposition disease

    International Nuclear Information System (INIS)

    A report of two patients in which a soft tissue mass, initially regarded as a malignant tumor, was shown to be the result of calcium pyrophosphate deposition disease. The first case, a woman aged 71 years, presented with a mass involving the right fifth finger. In the second case, also a women aged 71 years, the lesion involved the tissues adjacent to the right hip. Each lesion consisted of a mass of highly cellular tissue containing deposits of calcium pyrophosphate dihydrate crystals. The clinical, radiological, and pathological features of the two cases are compared with those of seven similar cases reported in the literature. (orig.)

  11. The preparation and antioxidant activity of glucosamine sulfate

    Science.gov (United States)

    Xing, Ronge; Liu, Song; Wang, Lin; Cai, Shengbao; Yu, Huahua; Feng, Jinhua; Li, Pengcheng

    2009-05-01

    Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O{2/-})/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O{2/-} scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.

  12. On the roles and regulation of chondroitin sulfate and heparan sulfate in zebrafish pharyngeal cartilage morphogenesis

    DEFF Research Database (Denmark)

    Holmborn, Katarina; Habicher, Judith; Kasza, Zsolt;

    2012-01-01

    The present study addresses the roles of heparan sulfate (HS) proteoglycans and chondroitin sulfate (CS) proteoglycans in the development of zebrafish pharyngeal cartilage structures. uxs1 and b3gat3 mutants, predicted to have impaired biosynthesis of both HS and CS because of defective formation...... higher levels of CS than control larvae, whereas morpholino-mediated suppression of csgalnact1/csgalnact2 resulted in increased HS biosynthesis. Thus, the balance of the Extl3 and Csgalnact1/Csgalnact2 proteins influences the HS/CS ratio. A characterization of the pharyngeal cartilage element...

  13. Discovery of a heparan sulfate 3-O-sulfation specific peeling reaction

    DEFF Research Database (Denmark)

    Huang, Yu; Mao, Yang; Zong, Chengli; Lin, Cheng; Boons, Geert-Jan; Zaia, Joseph

    2015-01-01

    mentioned above. By contrast, multiple distinct isoforms of 3-O-sulfotranserases exist in mammals (up to seven isoenzymes). Here we describe a novel peeling reaction that specifically degrades HS chains with 3-O-sulfated glucosamine at the reducing-end. When HS/heparin is enzymatically depolymerized for...... compositional analysis, 3-O-sulfated glucosamine at the reducing ends appears to be susceptible to degradation under mildly basic conditions. We propose a 3-O-desulfation initiated peeling reaction mechanism based on the intermediate and side-reaction products observed. Our discovery calls for the re...

  14. Testing Silica Fume-Based Concrete Composites under Chemical and Microbiological Sulfate Attacks

    Directory of Open Access Journals (Sweden)

    Adriana Estokova

    2016-04-01

    Full Text Available Current design practices based on descriptive approaches to concrete specification may not be appropriate for the management of aggressive environments. In this study, the durability of cement-based materials with and without the addition of silica fume, subjected to conditions that leach calcium and silicon, were investigated. Chemical corrosion was simulated by employing various H2SO4 and MgSO4 solutions, and biological corrosion was simulated using Acidithiobacillus sp. bacterial inoculation, leading to disrupted and damaged surfaces; the samples’ mass changes were studied following both chemical and biological attacks. Different leaching trends were observed via X-ray fluorescence when comparing chemical with biological leaching. Lower leaching rates were found for concrete samples fortified with silica fume than those without silica fume. X-ray diffraction and scanning electron microscopy confirmed a massive sulfate precipitate formation on the concrete surface due to bacterial exposure.

  15. Complex formation ions calcium with macromolecules pectin

    International Nuclear Information System (INIS)

    In clause the mechanism of sorption of ions of calcium by macromolecules of pectin is opened. Is shown, that the linkage of ions of calcium descends on acid bunches of pectin, and process carries cooperative character

  16. Mechanism of store-operated calcium entry

    Indian Academy of Sciences (India)

    Devkanya Dutta

    2000-12-01

    Activation of receptors coupled to the phospholipase C/IP3 signalling pathway results in a rapid release of calcium from its intracellular stores, eventually leading to depletion of these stores. Calcium store depletion triggers an influx of extracellular calcium across the plasma membrane, a mechanism known as the store-operated calcium entry or capacitative calcium entry. Capacitative calcium current plays a key role in replenishing calcium stores and activating various physiological processes. Despite considerable efforts, very little is known about the molecular nature of the capacitative channel and the signalling pathway that activates it. This review summarizes our current knowledge about store operated calcium entry and suggests possible hypotheses for its mode of activation.

  17. Dairy Dilemma: Are You Getting Enough Calcium?

    Science.gov (United States)

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

  18. Calcium, vitamin D, and your bones

    Science.gov (United States)

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

  19. Effects of sulfate deprivation on the production of chondroitin/dermatan sulfate by cultures of skin fibroblasts from normal and diabetic individuals

    International Nuclear Information System (INIS)

    Human skin fibroblast monolayer cultures from two normal men, three Type I diabetic men, and one Type I diabetic woman were incubated with [3H]glucosamine in the presence of diminished concentrations of sulfate. Although total synthesis of [3H]chondroitin/dermatan glycosaminoglycans varied somewhat between cell lines, glycosaminoglycan production was not affected within any line when sulfate levels were decreased from 0.3 mM to 0.06 mM to 0.01 mM to 0 added sulfate. Lowering of sulfate concentrations resulted in diminished sulfation of chondroitin/dermatan in a progressive manner, so that overall sulfation dropped to as low as 19% for one of the lines. Sulfation of chondroitin to form chondroitin 4-sulfate and chondroitin 6-sulfate was progressively and equally affected by decreasing the sulfate concentration in the culture medium. However, sulfation to form dermatan sulfate was preserved to a greater degree, so that the relative proportion of dermatan sulfate to chondroitin sulfate increased. Essentially all the nonsulfated residues were susceptible to chondroitin AC lyase, indicating that little epimerization of glucuronic acid residues to iduronic acid had occurred in the absence of sulfation. These results confirm the previously described dependency of glucuronic/iduronic epimerization on sulfation, and indicate that sulfation of the iduronic acid-containing disaccharide residues of dermatan can take place with sulfate concentrations lower than those needed for 6-sulfation and 4-sulfation of the glucuronic acid-containing disaccharide residues of chondroitin. There were considerable differences among the six fibroblast lines in susceptibility to low sulfate medium and in the proportion of chondroitin 6-sulfate, chondroitin 4-sulfate, and dermatan sulfate. However, there was no pattern of differences between normals and diabetics

  20. Effects of sulfate deprivation on the production of chondroitin/dermatan sulfate by cultures of skin fibroblasts from normal and diabetic individuals

    Energy Technology Data Exchange (ETDEWEB)

    Silbert, C.K.; Humphries, D.E.; Palmer, M.E.; Silbert, J.E. (Veterans Administration Outpatient Clinic, Boston, MA (USA))

    1991-02-15

    Human skin fibroblast monolayer cultures from two normal men, three Type I diabetic men, and one Type I diabetic woman were incubated with (3H)glucosamine in the presence of diminished concentrations of sulfate. Although total synthesis of (3H)chondroitin/dermatan glycosaminoglycans varied somewhat between cell lines, glycosaminoglycan production was not affected within any line when sulfate levels were decreased from 0.3 mM to 0.06 mM to 0.01 mM to 0 added sulfate. Lowering of sulfate concentrations resulted in diminished sulfation of chondroitin/dermatan in a progressive manner, so that overall sulfation dropped to as low as 19% for one of the lines. Sulfation of chondroitin to form chondroitin 4-sulfate and chondroitin 6-sulfate was progressively and equally affected by decreasing the sulfate concentration in the culture medium. However, sulfation to form dermatan sulfate was preserved to a greater degree, so that the relative proportion of dermatan sulfate to chondroitin sulfate increased. Essentially all the nonsulfated residues were susceptible to chondroitin AC lyase, indicating that little epimerization of glucuronic acid residues to iduronic acid had occurred in the absence of sulfation. These results confirm the previously described dependency of glucuronic/iduronic epimerization on sulfation, and indicate that sulfation of the iduronic acid-containing disaccharide residues of dermatan can take place with sulfate concentrations lower than those needed for 6-sulfation and 4-sulfation of the glucuronic acid-containing disaccharide residues of chondroitin. There were considerable differences among the six fibroblast lines in susceptibility to low sulfate medium and in the proportion of chondroitin 6-sulfate, chondroitin 4-sulfate, and dermatan sulfate. However, there was no pattern of differences between normals and diabetics.

  1. Effect of chondroitin sulfate on osteogenetic differentiation of human mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Schneiders, Wolfgang, E-mail: schneidersw@gmx.de; Rentsch, Claudia; Rehberg, Sebastian; Rein, Susanne; Zwipp, Hans; Rammelt, Stefan

    2012-10-01

    Chondroitin sulfate (CS) has anti-inflammatory properties and increases the regeneration ability of injured bone. In different in vivo investigations on bone defects the addition of CS to calcium phosphate bone cement has lead to an enhanced bone remodeling and increased new bone formation. The goal of this study was to evaluate the cellular effects of CS on human mesenchymal stem cells (hMSCs). In cell culture experiments hMSCs were incubated on calcium phosphate bone cements with and without CS and cultivated in a proliferation and an osteogenetic differentiation media. Alkaline phosphatase and the proliferation rate were determined on days 1, 7 and 14. Concerning the proliferation rates, no significant differences were detected. On days 1, 7 and 14 a significantly higher activity of alkaline phosphatase, an early marker of osteogenesis, was detected around CS modified cements in both types of media. The addition of CS leads to a significant increase of osteogenetic differentiation of hMSCs. To evaluate the influence of the osteoconductive potency of CS in twelve adult male Wistar rats, the interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (CDHA/Coll) without and with CS (CDHA/Coll/CS) was evaluated. Cylindrical implants were inserted press-fit into a defect of the tibial head. 28 days after the operation the direct bone contact and the percentage of newly formed bone were significantly higher on CDHA/Coll/CS-implants (p < 0.05). The addition of CS appears to enhance new bone formation on CDHA/Coll-composites in the early stages of bone healing. Possible mechanisms are discussed. - Highlights: Black-Right-Pointing-Pointer The influence of chondroitin sulfate (CS) on bone metabolism was evaluated. Black-Right-Pointing-Pointer CS leads to a significant increase of osteogenetic differentiation of hMSCs. Black-Right-Pointing-Pointer In small animal investigation CS seems to enhance osteogenesis in bone healing.

  2. Effect of chondroitin sulfate on osteogenetic differentiation of human mesenchymal stem cells

    International Nuclear Information System (INIS)

    Chondroitin sulfate (CS) has anti-inflammatory properties and increases the regeneration ability of injured bone. In different in vivo investigations on bone defects the addition of CS to calcium phosphate bone cement has lead to an enhanced bone remodeling and increased new bone formation. The goal of this study was to evaluate the cellular effects of CS on human mesenchymal stem cells (hMSCs). In cell culture experiments hMSCs were incubated on calcium phosphate bone cements with and without CS and cultivated in a proliferation and an osteogenetic differentiation media. Alkaline phosphatase and the proliferation rate were determined on days 1, 7 and 14. Concerning the proliferation rates, no significant differences were detected. On days 1, 7 and 14 a significantly higher activity of alkaline phosphatase, an early marker of osteogenesis, was detected around CS modified cements in both types of media. The addition of CS leads to a significant increase of osteogenetic differentiation of hMSCs. To evaluate the influence of the osteoconductive potency of CS in twelve adult male Wistar rats, the interface reaction of cancellous bone to a nanocrystalline hydroxyapatite cement containing type I collagen (CDHA/Coll) without and with CS (CDHA/Coll/CS) was evaluated. Cylindrical implants were inserted press-fit into a defect of the tibial head. 28 days after the operation the direct bone contact and the percentage of newly formed bone were significantly higher on CDHA/Coll/CS-implants (p < 0.05). The addition of CS appears to enhance new bone formation on CDHA/Coll-composites in the early stages of bone healing. Possible mechanisms are discussed. - Highlights: ► The influence of chondroitin sulfate (CS) on bone metabolism was evaluated. ► CS leads to a significant increase of osteogenetic differentiation of hMSCs. ► In small animal investigation CS seems to enhance osteogenesis in bone healing.

  3. Uranium Immobilization by Sulfate-reducing Biofilms

    International Nuclear Information System (INIS)

    Hexavalent uranium [U(VI)] was immobilized using biofilms of the sulfate-reducing bacterium (SRB) Desulfovibrio desulfuricans G20. The biofilms were grown in flat-plate continuous-flow reactors using lactate as the electron donor and sulfate as the electron acceptor. U(VI) was continuously fed into the reactor for 32 weeks at a concentration of 126 ?M. During this time, the soluble U(VI) was removed (between 88 and 96% of feed) from solution and immobilized in the biofilms. The dynamics of U immobilization in the sulfate-reducing biofilms were quantified by estimating: (1) microbial activity in the SRB biofilm, defined as the hydrogen sulfide (H2S) production rate and estimated from the H2S concentration profiles measured using microelectrodes across the biofilms; (2) concentration of dissolved U in the solution; and (3) the mass of U precipitated in the biofilm. Results suggest that U was immobilized in the biofilms as a result of two processes: (1) enzymatically and (2) chemically, by reacting with microbially generated H2S. Visual inspection showed that the dissolved sulfide species reacted with U(VI) to produce a black precipitate. Synchrotron-based U L3-edge X-ray absorption near edge structure (XANES) spectroscopy analysis of U precipitated abiotically by sodium sulfide indicated that U(VI) had been reduced to U(IV). Selected-area electron diffraction pattern and crystallographic analysis of transmission electron microscope lattice-fringe images confirmed the structure of precipitated U as being that of uraninite

  4. Calcium channel blockers and Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Yi Tan; Yulin Deng; Hong Qing

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofi-brillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers in-volved in Alzheimer's disease therapy.

  5. Calcium channel blockers and Alzheimer's disease★

    OpenAIRE

    Tan, Yi; Deng, Yulin; Qing, Hong

    2012-01-01

    Alzheimer's disease is characterized by two pathological hallmarks: amyloid plaques and neurofibrillary tangles. In addition, calcium homeostasis is disrupted in the course of human aging. Recent research shows that dense plaques can cause functional alteration of calcium signals in mice with Alzheimer's disease. Calcium channel blockers are effective therapeutics for treating Alzheimer's disease. This review provides an overview of the current research of calcium channel blockers involved in...

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

    Science.gov (United States)

    Liang, Willmann

    2008-01-01

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

  7. New Bioactive Alkyl Sulfates from Mediterranean Tunicates

    Directory of Open Access Journals (Sweden)

    Marialuisa Menna

    2012-10-01

    Full Text Available Chemical investigation of two species of marine ascidians, Aplidium elegans and Ciona edwardsii, collected in Mediterranean area, led to isolation of a series of alkyl sulfates (compounds 1–5 including three new molecules 1–3. Structures of the new metabolites have been elucidated by spectroscopic analysis. Based on previously reported cytotoxic activity of these type of molecules, compounds 1–3 have been tested for their effects on the growth of two cell lines, J774A.1 (BALB/c murine macrophages and C6 (rat glioma in vitro. Compounds 1 and 2 induced selective concentration-dependent mortality on J774A.1 cells.

  8. Thermodynamics of aqueous sodium dodecyl sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Berg, R.L.

    1977-08-01

    A flow microcalorimeter system was assembled and is being used in a thermodynamic study of surfactant systems as part of the ERDA enhanced oil recovery program. Enthalpies of dilution and demicellization of sodium dodecyl sulfate were measured over a temperature range of 20 to 35/sup 0/C. This surfactant was also studied with cosurfactant and salt backgrounds. The critical micelle concentrations (cmc) were determined and are in excellent agreement with those in the literature. Studies below the cmc suggest the possible formation of a dimer. 17 tables, 9 figures.

  9. Structure of double hafnium and rubidium sulfate

    International Nuclear Information System (INIS)

    The crystal structure of the Hf(SO4)2x2Rb(SO4)H2O is studied. For the rhombic crystals the space group is P212121 with cell parameters a=9.728(2), b=12.493(2), c=15.025(3) A, and Z=4. The compound structure belongs to the type of chain structures. The Hf atom is surrounded by seven O atoms belonging to two bidentate-cyclic, bidentate-bridge and monodentate sulfate groups forming a pentagonal bipyramid. The interatomic distances and valent angles in the Hf polyhedron and SO4 tetrahedrons are presented

  10. Electrophysical properties of calcium orthovanadate

    International Nuclear Information System (INIS)

    The electron conductivity, dielectric permeability and magnetic susceptibility of calcium orthovanadate are studied. It is shown that structural transformations bring about changes in the nature of electrophysical properties of Ca3(VO4)2 and cause the charge redistribution in VO43- anion groups

  11. SULFATION OF ARABINOGALACTAN BY SULFAMIC ACID IN DIOXANE MEDIUM

    Directory of Open Access Journals (Sweden)

    Наталья Юрьевна Васильева

    2014-09-01

    Full Text Available Sulfation of arabinogalactan (AG by sulfamic acid in the presence of urea at temperatures 70–95 °C in dioxane medium was studied. The growth of sulfation temperature from 70 to 95 °C increases a degree of AG sulfation. According to NMR 13C spectroscopy data sulfate groups are fixed at С2 and C4 positions of galactose unit of basic chain and at C6 position of terminal galactose units of basic and side chains of arabinogalactan. The sulfation of AG by complex sulfamic acid – urea in dioxane medium makes possible to increase the environmental safety and efficiency of the process as compared to the known sulfation methods.

  12. Removal of Sulfate Ion From AN-107 by Evaporation

    International Nuclear Information System (INIS)

    Hanford low-activity waste solutions contain sulfate, which can cause accelerated corrosion of the vitrification melter and unacceptable operating conditions. A method is needed to selectively separate sulfate from the waste. An experiment was conducted to evaluate evaporation for removing sulfate ion from Tank AN-107 low-activity waste. Two evaporation steps were performed. In the first step, the volume was reduced by 55% while in the second step, the liquid volume was reduced another 22%. Analysis of the solids precipitated during these evaporations revealed that large amounts of sodium nitrate and nitrite co-precipitated with sodium sulfate. Many other waste components precipitated as well. It can be concluded that sulfate removal by precipitation is not selective, and thus, evaporation is not a viable option for removing sulfate from the AN-107 liquid

  13. Diversity of sulfur isotope fractionations by sulfate-reducing prokaryotes

    DEFF Research Database (Denmark)

    Detmers, Jan; Brüchert, Volker; Habicht, K S;

    2001-01-01

    Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known.......0 to 42.0 per thousand. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation....... Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect...

  14. 21 CFR 582.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  15. 21 CFR 182.1217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

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

  16. 21 CFR 582.5217 - Calcium phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium phosphate. 582.5217 Section 582.5217 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5217 Calcium phosphate. (a) Product. Calcium phosphate (mono-, di-, and tribasic)....

  17. 21 CFR 582.1191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.1191 Section 582.1191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  18. 21 CFR 582.5191 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium carbonate. 582.5191 Section 582.5191 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5191 Calcium carbonate. (a) Product. Calcium carbonate. (b) Conditions of use....

  19. 21 CFR 73.1070 - Calcium carbonate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Calcium carbonate. 73.1070 Section 73.1070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1070 Calcium carbonate. (a) Identity. (1) The color additive calcium carbonate is a fine,...

  20. 21 CFR 582.1205 - Calcium hydroxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium hydroxide. 582.1205 Section 582.1205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use....

  1. 21 CFR 182.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 182.2227 Section 182.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2227 Calcium silicate. (a) Product. Calcium silicate....

  2. 21 CFR 582.2227 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Calcium silicate. 582.2227 Section 582.2227 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Calcium silicate. (a) Product. Calcium silicate. (b) Tolerance. 2 percent and 5 percent. (c)...

  3. Calcium dynamics in vascular smooth muscle

    OpenAIRE

    Amberg, Gregory C.; Navedo, Manuel F.

    2013-01-01

    Smooth muscle cells are ultimately responsible for determining vascular luminal diameter and blood flow. Dynamic changes in intracellular calcium are a critical mechanism regulating vascular smooth muscle contractility. Processes influencing intracellular calcium are therefore important regulators of vascular function with physiological and pathophysiological consequences. In this review we discuss the major dynamic calcium signals identified and characterized in vascular smooth muscle cells....

  4. Lactulose stimulates calcium absorption in postmenopausal women

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muijs, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Animal studies have indicated that calcium absorption is increased by lactulose, a synthetic disaccharide. Therefore, the influence of lactulose on calcium absorption was measured in postmenopausal women who may benefit from the possible enhancing effect of lactulose on calcium absorption. Twelve po

  5. Dimethylsulfoxide reduction by marine sulfate-reducing bacteria

    OpenAIRE

    Jonkers, Henk M.; van der Maarel, Marc J. E. C.; van Gemerden, Hans; Hansen, Theo A.

    1996-01-01

    Dimethylsulfoxide (DMSO) reduction occurred in five out of nine strains of sulfate-reducing bacteria from marine or saline environments, but not in three freshwater isolates. DMSO reduction supported growth in all positive strains. In Desulfovibrio desulfuricans strain PA2805, DMSO reduction occurred simultaneously-with sulfate reduction and was not effectively inhibited by molybdate, a specific inhibitor of sulfate reduction. The growth yield per mol lactate was 26% higher with DMSO than wit...

  6. Distribution of Heparan Sulfate Oligosaccharides in Murine Mucopolysaccharidosis Type IIIA

    OpenAIRE

    Kerryn Mason; Peter Meikle; John Hopwood; Maria Fuller

    2014-01-01

    Heparan sulfate (HS) catabolism begins with endo-degradation of the polysaccharide to smaller HS oligosaccharides, followed by the sequential action of exo-enzymes to reduce these oligosaccharides to monosaccharides and inorganic sulfate. In mucopolysaccharidosis type IIIA (MPS IIIA) the exo-enzyme, N-sulfoglucosamine sulfohydrolase, is deficient resulting in an inability to hydrolyze non-reducing end glucosamine N-sulfate esters. Consequently, partially degraded HS oligosaccharides with non-...

  7. Marine Non-Glycosaminoglycan Sulfated Glycans as Potential Pharmaceuticals

    OpenAIRE

    Vitor H. Pomin

    2015-01-01

    Sulfated fucans (SFs) and sulfated galactans (SGs) are currently the marine non-glycosaminoglycan (GAG) sulfated glycans most studied in glycomics. These compounds exhibit therapeutic effects in several pathophysiological systems such as blood coagulation, thrombosis, neovascularization, cancer, inflammation, and microbial infections. As analogs of the largely employed GAGs and due to some limitations of the GAG-based therapies, SFs and SGs comprise new carbohydrate-based therapeutics availab...

  8. Renal localization of heparan sulfate proteoglycan by immunohistochemistry.

    OpenAIRE

    Klein, D. J.; Oegema, T.R.; Eisenstein, R.; Furcht, L.; Michael, A. F.; Brown, D M

    1983-01-01

    Glomerular localization of heparan sulfate proteoglycan (HS-proteoglycan) has been studied immunohistochemically with a highly purified antiserum to bovine aorta HS-proteoglycan core protein. The specificity of the antiserum was enhanced by consecutive fibronectin and chondroitin sulfate-dermatan sulfate proteoglycan (CS-DS proteoglycan) affinity chromatography. The affinity-purified HS-proteoglycan antibody lacked cross-reactivity by enzyme-linked immunosorbent assays (ELISA) with CS-DS prot...

  9. Human Papillomavirus Infection Requires Cell Surface Heparan Sulfate

    OpenAIRE

    Giroglou, Tzenan; Florin, Luise; Schäfer, Frank; Streeck, Rolf E.; Sapp, Martin

    2001-01-01

    Using pseudoinfection of cell lines, we demonstrate that cell surface heparan sulfate is required for infection by human papillomavirus type 16 (HPV-16) and HPV-33 pseudovirions. Pseudoinfection was inhibited by heparin but not dermatan or chondroitin sulfate, reduced by reducing the level of surface sulfation, and abolished by heparinase treatment. Carboxy-terminally deleted HPV-33 virus-like particles still bound efficiently to heparin. The kinetics of postattachment neutralization by antis...

  10. Effective Synthesis of Sulfate Metabolites of Chlorinated Phenols

    OpenAIRE

    Lehmler, Hans-Joachim; He, Xianran; Li, Xueshu; Duffel, Michael W.; Parkin, Sean

    2013-01-01

    Chlorophenols are an important class of persistent environmental contaminants and have been implicated in a range of adverse health effects, including cancer. They are readily conjugated and excreted as the corresponding glucuronides and sulfates in the urine of humans and other species. Here we report the synthesis and characterization of a series of ten chlorophenol sulfates by sulfation of the corresponding chlorophenols with 2,2,2-trichloroethyl (TCE) chlorosulfate using N,N-dimethylamino...

  11. Sulfation of ractopamine and salbutamol by the human cytosolic sulfotransferases

    OpenAIRE

    Ko, KyoungA; Kurogi, Katsuhisa; Davidson, Garrett; Liu, Ming-Yih; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2012-01-01

    Feed additives such as ractopamine and salbutamol are pharmacologically active compounds, acting primarily as β-adrenergic agonists. This study was designed to investigate whether the sulfation of ractopamine and salbutamol may occur under the metabolic conditions and to identify the human cytosolic sulfotransferases (SULTs) that are capable of sulfating two major feed additive compounds, ractopamine and salbutamol. A metabolic labelling study showed the generation and release of [35S]sulfate...

  12. Investigation of Sulfate Attack by Experimental and Thermodynamic Means

    OpenAIRE

    Kunther, Wolfgang

    2012-01-01

    This work investigates sulfate attack in complex sulfate environments by exposing different binder types to various sulfate solutions and comparing predicted phase and volume changes with experimental data. The most important aspects of this work can be grouped in three topics: The comparison of the predicted volume increase with the experimentally observed length changes. This part of the work shows that volume increase cannot be linked direct...

  13. Wet deposition of elemental carbon and sulfate in Sweden

    OpenAIRE

    Ogren, J.A.; R. J. Charlson

    2011-01-01

    Elemental carbon and sulfate were measured in monthly precipitation samples at 12 rural sites inSweden from April to August, 1981. Wet deposition of excess sulfate was significantly correlatedwith elemental carbon deposition, and no systematic spatial or temporal variations in the ratio ofexcess sulfate to elemental carbon were observed. Comparision of these results with sulfur andelemental carbon emissions in Western Europe suggests that elemental carbon is removed at aslower rate than sulfu...

  14. 21 CFR 524.960 - Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions.

    Science.gov (United States)

    2010-04-01

    ... sulfate ophthalmic solutions. 524.960 Section 524.960 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND... ophthalmic solutions. (a) Specifications. Each milliliter of ophthalmic preparation contains 0.10...

  15. Analytical model for freeboard and in-bed limestone sulfation in fluidized-bed coal combustors

    Energy Technology Data Exchange (ETDEWEB)

    Fee, D.C.; Myles, K.M.; Marroquin, G.; Fan, L.S.

    1984-01-01

    A new model, which combines in-bed and freeboard sulfation, significantly improves the ability to predict sulfur capture by limestone sorbents in fluidized-bed coal combustors. In this model, the in-bed hydrodynamics are described in terms of a bubble phase and an emulsion phase while the freeboard region has only a diluted emulsion phase. The solids, which are in the emulsion phases, are considered to be completely back-mixed; the gaseous bubble phase travels in plug-flow but exchanges with the emulsion phase. The sulfation reaction occurs principally in the emulsion phase and the reaction rate is a direct function of the sulfur dioxide concentration, the extent of the calcium oxide conversion (as measured by a thermogravimetric analyzer), and the amount of limestone present in the bed and in the freeboard. The amount present, or holdup, in the free-board is calculated from empirical correlations for elutriation and from particle-time trajectories as predicted from equations of motion. 19 references, 4 figures.

  16. Influence of water hardness and sulfate on the acute toxicity of chloride to sensitive freshwater invertebrates.

    Science.gov (United States)

    Soucek, David J; Linton, Tyler K; Tarr, Christopher D; Dickinson, Amy; Wickramanayake, Nilesh; Delos, Charles G; Cruz, Luis A

    2011-04-01

    Total dissolved solids (TDS) represent the sum of all common ions (e.g., Na, K, Ca, Mg, chloride, sulfate, and bicarbonate) in freshwater. Currently, no federal water quality criteria exist for the protection of aquatic life for TDS, but because the constituents that constitute TDS are variable, the development of aquatic life criteria for specific ions is more practical than development of aquatic life criteria for TDS. Chloride is one such ion for which aquatic life criteria exist; however, the current aquatic life criteria dataset for chloride is more than 20 years old. Therefore, additional toxicity tests were conducted in the current study to confirm the acute toxicity of chloride to several potentially sensitive invertebrates: water flea (Ceriodaphnia dubia), fingernail clams (Sphaerium simile and Musculium transversum), snail (Gyraulus parvus), and worm (Tubifex tubifex), and determine the extent to which hardness and sulfate modify chloride toxicity. The results indicated a significant ameliorating effect of water hardness (calcium and magnesium) on chloride toxicity for all species tested except the snail; for example, the 48-h chloride median lethal concentration (LC50) for C. dubia at 50 mg/L hardness (977 mg Cl(-) /L) was half that at 800 mg/L hardness (1,836 mg Cl(-) /L). Conversely, sulfate over the range of 25 to 600 mg/L exerted a negligible effect on chloride toxicity to C. dubia. Rank order of LC50 values for chloride at a given water hardness was in the order (lowest to highest): S. simile tubifex. Results of the current study support the contention that the specific conductivity or TDS concentration of a water body alone is not a sufficient predictor of acute toxicity and that knowledge of the specific ion composition is critical. PMID:21191883

  17. Susceptibility to bacterial pneumonia of animals exposed to sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Ehrlich, R.; Findlay, J.C.; Gardner, D.E.

    1978-03-01

    Susceptibility of mice to respiratory infections caused by exposure to sulfate aerosols was investigated. Inhalation of zinc sulfate or zinc ammonium sulfate followed by a respiratory challenge with airborne Streptococcus pyogenes resulted in excess mortality and reduced survival time. Estimated concentration of ZnSO4 that caused 20% excess mortality was 1.45 mg/cu m, and of Zn(NH4)2(SO4)2 was 2.40 mg/cu m for the 3 h inhalation exposure. Studies were extended to include the effects of various sulfates emitted from mobile and stationary sources to streptococcal pneumonia. (2 graphs, 7 references, 1 table)

  18. Mencegah Pembentukan Kalsium Sulfat pada Desalinasi Air Laut

    Directory of Open Access Journals (Sweden)

    Mirna Rahmah Lubis

    2007-06-01

    Full Text Available Resin penukar-anion, Relite MG 1/P, dapat digunakan untuk memisahkan sulfat dalam air laut guna mencegah pembentukan kerak kalsium sulfat pada heat exchanger. Resin tersebut menunjukkan selektivitas sulfat yang tinggi dalam air laut sintetis. Resin yang telah dipakai dapat diregenerasi menggunakan air asin yang dipekatkan dengan asam hingga mencapai pH 4. Untuk waktu pemakaian dan regenerasi yang sama, faktor konsentrasi desalinasi (misalnya 2 hingga 4 menaikkan konsentrasi klorida dalam air asin yang diblowdown. Dengan faktor konsentrasi yang tetap, kenaikan laju alir (pengurangan waktu pemakaian dan regenerasi memperendah efisiensi regenerasi dan menaikkan pemisahan sulfat. Akibat kelarutan kalsium sulfat yang bersifat terbalik tersebut, temperatur air asin yang tinggi memerlukan pemisahan sulfat yang lebih banyak, yang dapat dicapai dengan mengurangi laju alir air laut. Pengurangan laju alir tersebut membutuhkan peralatan yang lebih besar dan resin yang lebih banyak, sehingga biaya modal bertambah. Untuk pabrik desalinasi dengan kapasitas produksi 1 juta gallon per hari dan faktor konsentrasi sebesar 2, biaya pemisahan sulfat meliputi biaya resin dan biaya peralatan. Biaya tersebut bervariasi dari $0.246 hingga $0.356/kgalon (per ribu galon air yang diproduksi karena temperatur maksimum air asin berubah dari 140°C menjadi 180°C. Keywords: desalinasi air laut, ion exchange, kalsium sulfat, kerak; mechanical vapor compression (MVC, pemisahan sulfat, resin penukar-anion basa lemah

  19. An Instrument to Measure Aircraft Sulfate Particle Emissions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerodyne is developing a sulfate detection instrument, based on the Tunable Infrared Laser Differential Absorption Spectrophotometer (TILDAS) technology and...

  20. Separation of 35S-sulfate on neutral aluminium oxide

    International Nuclear Information System (INIS)

    The results of 35S-sulfate chromatography on neutral aluminium oxide (γ-Al2O3) are presented. Possibility of quantitative adsorption of 35S-sulfate on Al2O3 from acidic or neutral potassium chloride solutions of high concentration is shown. Dynamic adsorption capacity of neutral aluminium oxide with respect to sulfate from weakly acidic potassium chloride solution equals near 10 μmol/ml of adsorbent. Optimal parameters for chromatographic isolation of 35S-sulfate without carrier from irradiated KCl target are determined. (author)

  1. METHOD OF INHIBITING CORROSION IN URANYL SULFATE SOLUTIONS

    Science.gov (United States)

    Bohlmann, E.G.; Griess, J.C. Jr.

    1960-08-23

    A method is given for treating a uranyl sulfate solution to inhibit the corrosiveness of the solution and elevate the phase separation temperature of the solution. Lithium sulfate is added to the solution in an amount ranging from 0.25 to 1.3 times the uranyl sulfate concentration. The corrosiveness of the solution with respect to stainless steel is substantially decreased by this means. This treatment also serves to raise the phase separation temperature of the solution (above 250 deg C), at which time the uranyl sulfate solution separates into two liquid phases of unequal uranium concentration and thus becomes unsuitable as nuclear reactor fuel.

  2. Sodium/Calcium Exchangers Selectively Regulate Calcium Signaling in Mouse Taste Receptor Cells

    OpenAIRE

    Szebenyi, Steven A.; Laskowski, Agnieszka I.; Medler, Kathryn F.

    2010-01-01

    Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contrib...

  3. Calcium electroporation in three cell lines; a comparison of bleomycin and calcium, calcium compounds, and pulsing conditions

    DEFF Research Database (Denmark)

    Frandsen, Stine Krog; Gissel, Hanne; Hojman, Pernille;

    2013-01-01

    BACKGROUND: Electroporation with calcium (calcium electroporation) can induce ATP depletion-associated cellular death. In the clinical setting, the cytotoxic drug bleomycin is currently used with electroporation (electrochemotherapy) for palliative treatment of tumors. Calcium electroporation...... offers several advantages over standard treatment options: calcium is inexpensive and may readily be applied without special precautions, as is the case with cytostatic drugs. Therefore, details on the use of calcium electroporation are essential for carrying out clinical trials comparing calcium...... electroporation and electrochemotherapy. METHODS: The effects of calcium electroporation and bleomycin electroporation (alone or in combination) were compared in three different cell lines (DC-3F, transformed Chinese hamster lung fibroblast; K-562, human leukemia; and murine Lewis Lung Carcinoma). Furthermore...

  4. Controls of Soluble Al in Experimental Acid Sulfate Conditions and Acid Sulfate Soils

    Institute of Scientific and Technical Information of China (English)

    LINCHUXIA; M.D.MELVILLE

    1997-01-01

    The controls of soluble Al concentration were examined in three situations of acid sulfate conditions:1) experimental acid sulfate conditions by addition of varying amounts of Al(OH)3(gibbsite) into a sequence of H2SO4 solutions;2)experimental acid sulfate conditions by addition of the same sequence of H2SO4 solutions into two non-cid sulfacte soil samples with known amounts of acid oxalate extractable Al; and 3) actual acid sulfate soil conditions.The experiment using gibbsite as an Al-bearing mineral showed that increase in the concentration of H2SO4 solution increased the soluble Al concentration,accompanied by a decrease i the solution pH, Increasing amount of gibbsite added to the H2SO4 solutions also increased soluble Al concentration,but resulted in an increase in solution pH.Within the H2SO4 concentration range of 0.0005-0.5mol L-1 and the Al(OH)3 range of 0.01-0.5g(in 25 mL of H2SO4 solutions),the input of H2SO4 had the major control on soluble Al Concentration and pH .The availability of Al(OH)3,however,was responsible for the spread fo the various sample points,with a tendency that the samples containing more gibbsite had a higher soluble Al concentration than those containing less gibbsite at equivalent pH levels.The experimental results from treatment of soil samples with H2SO4 solutions and the analytical results of acid sulfate soils also showed the similar trend.

  5. Effect of anions or foods on absolute bioavailability of calcium from calcium salts in mice by pharmacokinetics

    OpenAIRE

    Zenei Taira, Zenei

    2013-01-01

    Yukari Ueda, Zenei TairaFaculty of Pharmaceutical Sciences, Tokushima Bunri University, Tokushima, JapanAbstract: We studied the absolute bioavailability of calcium from calcium L-lactate in mice using pharmacokinetics, and reviewed the absolute bioavailability of calcium from three other calcium salts in mice previously studied: calcium chloride, calcium acetate, and calcium ascorbate. The results showed that calcium metabolism is linear between intravenous administration of 15 mg/kg and 30 ...

  6. Optimizing substrate for sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Microbial sulfate reduction followed by sulfide precipitation effectively removes heavy metals from wastewaters. The substrate in the anaerobic zone in a constructed wetland can be designed to emphasize this removal process. This group of bacteria requires CH2O, P, N, and SO4=, reducing conditions, and pH range of 5-9 (pH=7 is optimum). The objective of this study was to find an inexpensive source of nutrients that would give the best initial production of sulfide and make a good wetland substrate. All tested materials contain sufficient P and N; mine drainage provides sulfate. Thus, tests focused on finding organic material that provides the proper nutrients and does not cause the culture to fall below pH of 5. Among chemical nutrients, sodium lactate combined with (NH4)2HPO4 were the only compounds that produced sulfide after 11 days. Among complex nutrients, only cow manure produced sulfide after 26 days. Among complex carbohydrates, cracked corn and raw rice produced sulfide after 10 days. Most substrates failed to produce sulfide because anaerobic fermentation reduced the pH below 5. Presently, cracked corn is the best candidate for a substrate. Five grams of cow manure produced 0.14 millimole of sulfide whereas 0.1 g of cracked corn produced 0.22 millimole

  7. Divergent Synthesis of Chondroitin Sulfate Disaccharides and Identification of Sulfate Motifs that Inhibit Triple Negative Breast Cancer

    Science.gov (United States)

    Wei Poh, Zhong; Heng Gan, Chin; Lee, Eric J.; Guo, Suxian; Yip, George W.; Lam, Yulin

    2015-09-01

    Glycosaminoglycans (GAGs) regulate many important physiological processes. A pertinent issue to address is whether GAGs encode important functional information via introduction of position specific sulfate groups in the GAG structure. However, procurement of pure, homogenous GAG motifs to probe the “sulfation code” is a challenging task due to isolation difficulty and structural complexity. To this end, we devised a versatile synthetic strategy to obtain all the 16 theoretically possible sulfation patterns in the chondroitin sulfate (CS) repeating unit; these include rare but potentially important sulfated motifs which have not been isolated earlier. Biological evaluation indicated that CS sulfation patterns had differing effects for different breast cancer cell types, and the greatest inhibitory effect was observed for the most aggressive, triple negative breast cancer cell line MDA-MB-231.

  8. Calcium signals and calcium channels in osteoblastic cells

    Science.gov (United States)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  9. Computational study of a calcium release-activated calcium channel

    Science.gov (United States)

    Talukdar, Keka; Shantappa, Anil

    2016-05-01

    The naturally occurring proteins that form hole in membrane are commonly known as ion channels. They play multiple roles in many important biological processes. Deletion or alteration of these channels often leads to serious problems in the physiological processes as it controls the flow of ions through it. The proper maintenance of the flow of ions, in turn, is required for normal health. Here we have investigated the behavior of a calcium release-activated calcium ion channel with pdb entry 4HKR in Drosophila Melanogaster. The equilibrium energy as well as molecular dynamics simulation is performed first. The protein is subjected to molecular dynamics simulation to find their energy minimized value. Simulation of the protein in the environment of water and ions has given us important results too. The solvation energy is also found using Charmm potential.

  10. Growth performance and root transcriptome remodeling of Arabidopsis in response to Mars-like levels of magnesium sulfate.

    Directory of Open Access Journals (Sweden)

    Anne M Visscher

    Full Text Available BACKGROUND: Martian regolith (unconsolidated surface material is a potential medium for plant growth in bioregenerative life support systems during manned missions on Mars. However, hydrated magnesium sulfate mineral levels in the regolith of Mars can reach as high as 10 wt%, and would be expected to be highly inhibitory to plant growth. METHODOLOGY AND PRINCIPAL FINDINGS: Disabling ion transporters AtMRS2-10 and AtSULTR1;2, which are plasma membrane localized in peripheral root cells, is not an effective way to confer tolerance to magnesium sulfate soils. Arabidopsis mrs2-10 and sel1-10 knockout lines do not mitigate the growth inhibiting impacts of high MgSO(4.7H(2O concentrations observed with wildtype plants. A global approach was used to identify novel genes with potential to enhance tolerance to high MgSO(4.7H(2O (magnesium sulfate stress. The early Arabidopsis root transcriptome response to elevated concentrations of magnesium sulfate was characterized in Col-0, and also between Col-0 and the mutant line cax1-1, which was confirmed to be relatively tolerant of high levels of MgSO(4.7H(2O in soil solution. Differentially expressed genes in Col-0 treated for 45 min. encode enzymes primarily involved in hormone metabolism, transcription factors, calcium-binding proteins, kinases, cell wall related proteins and membrane-based transporters. Over 200 genes encoding transporters were differentially expressed in Col-0 up to 180 min. of exposure, and one of the first down-regulated genes was CAX1. The importance of this early response in wildtype Arabidopsis is exemplified in the fact that only four transcripts were differentially expressed between Col-0 and cax1-1 at 180 min. after initiation of treatment. CONCLUSIONS/SIGNIFICANCE: The results provide a solid basis for the understanding of the metabolic response of plants to elevated magnesium sulfate soils; it is the first transcriptome analysis of plants in this environment. The results foster

  11. Substitution of calcium by strontium within selected calcium phosphates

    Science.gov (United States)

    Rokita, E.; Hermes, C.; Nolting, H.-F.; Ryczek, J.

    1993-06-01

    Sr incorporation in the molecules of amorphous calcium phosphate, apatitic tricalcium phosphate, hydroxyapatite, octacalcium phosphate and dicalcium phosphate dihydrate was investigated. The concentration of Sr ranged from 225 to 1010 μ g / g, i.e. it overlapped with the physiological range of Sr concentrations in human bone. The leading experimental technique was extended X-ray absorption fine structure (EXAFS) at the Sr K edge. Results of these studies demonstrated the following: (1) Sr incorporation in the calcium phosphates is compound-dependent, (2) the coordination of incorporated Sr atoms in the Ca-P molecules is similar to that of Ca atoms, but interatomic distances are ≈0.015 nm larger, (3) in apatitic tricalcium phosphate, hydroxyapatite and octacalcium phosphate lattices Sr atoms may occupy selected Ca sites, which was not the case for dicalcium phosphate dihydrate, (4) in the apatite lattice Sr atoms are coordinated by 6 PO 4 tetrahedrals and (5) EXAFS spectra at the K edge of the incorporated Sr may be used to distinguish the structures of amorphous calcium phosphate, dicalcium phosphate dihydrate as well as apatite and its derivatives (apatitic tricalcium phosphate, octacalcium phosphate).

  12. USING CALCIUM CARBONATE WHISKERS AS PAPERMAKING FILLER

    Directory of Open Access Journals (Sweden)

    Xiaoyu Chen

    2011-05-01

    Full Text Available Whiskers, having large length/diameter ratio, are fiber-shaped single crystals. The technical possibility of using calcium carbonate whiskers as papermaking filler to replace conventional powder-like calcium carbonate was investigated. The results showed that it may be feasible to use calcium carbonate whisker as papermaking filler. Compared with conventional precipitated calcium carbonate, calcium carbonate whisker had higher retention efficiency. The use of calcium carbonate whisker also favorably affected the strength properties of paper sheets. A model was proposed to suggest the mechanism for paper strength improvement. The whiskers filled in paper sheets could increase the friction between fibers, thus increasing bonding strength. Moreover, the strength properties of paper were further improved because calcium carbonate whiskers were partly embedded in pulp fiber walls.

  13. CALCIUM ENHANCES ANTIINFLAMMATORY ACTIVITY OF ASPIRIN

    Directory of Open Access Journals (Sweden)

    Choksi Krishna

    2011-03-01

    Full Text Available The objective of present study is to evaluate the effects of calcium carbonate and calcium gluconate on acute and subacute inflammation and to study their possible interactions with Aspirin. Calcium carbonate (10 mg/kg and calcium gluconate (5 mg/kg were administered individually and also co-administered along with sub therapeutic dose Aspirin (50mg/kg to study their interaction. The inflammation was induced by carrageenan or a foreign body. Both calcium carbonate and calcium gluconate could not show significant anti-inflammatory activity on their own in acute as well as subacute inflammation models. Aspirin at sub-anti-inflammatory dose (50mg/Kg when co-administered along with calcium salts produced the significant anti-inflammatory response which was comparable to anti-inflammatory response of aspirin at therapeutic dose (200mg/Kg. Also co-adminostration minimized the gastro-toxicity of aspirin.

  14. Physical and chemical properties of fish and chicken bones as calcium source for mineral supplements

    Directory of Open Access Journals (Sweden)

    Worapot Suntornsuk

    2006-03-01

    Full Text Available Physical and chemical properties of two bones of two species of fish, hoki (Macruronus novaezelandiae and giant seaperch (Lates calcarifer Bloch., were compared with chicken bone to evaluate their composition for use as natural calcium supplement. The information could be useful for waste utilization in the food and pharmaceutical industries. Physical testing and chemical analyses were performed according to the USP 24 and BP 1998 standards under calcium carbonate monograph. Loss on drying found in hoki, giant seaperch and chicken bones was 12.4, 11.3 and 5.9 % w/w, calculated on dried basis, respectively. Total calcium determined by complexometric titration was 31.8, 28.1 and 32.2% w/w in hoki, giant seaperch and chicken bones, respectively. All samples contained carbonate and phosphate anion residues but gluconate, acetate and citrate were absent. The presence of calcium carbonate was confirmed by thermogravimetry. Results from all bones showed that limit tests for heavy metals, arsenic and iron complied with the USP standard, whereas barium, chloride and sulfate conformed to the BP standard. The magnesium and alkali metals in giant seaperch bone were within the BP limit (1.5%, but those of hoki and chicken bone exceeded the limit.

  15. The chemical transformation of calcium in Shenhua coal during combustion in a muffle furnace

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Sida [North China Electric Power Univ., Beijing (China). School of Energy, Power and Mechanical Engineering; Ministry of Education, Beijing (China). Key Lab. of Condition Monitoring and Control for Power Plant Equipment; Zhuo, Yuqun; Chen, Changhe [Tsinghua Univ., Beijing (China). Dept. of Thermal Engineering; Ministry of Education, Beijing (China). Key Lab. for Thermal Science and Power Engineering; Shu, Xinqian [China Univ. of Mining and Technology, Beijing (China). School of Chemical and Environmental Engineering

    2013-07-01

    The chemical reaction characteristics of calcium in three samples of Shenhua coal, i.e. raw sample, hydrochloric acid washed sample and hydrochloric acid washed light fraction, during combustion in a muffle furnace have been investigated in this paper. Ca is bound by calcite and organic matter in Shenhua coal. X ray diffraction (XRD) phase analysis has been conducted to these samples' combustion products obtained by heating at different temperatures. It has been found that the organically-bound calcium could easily react with clays and transform into gehlenite and anorthite partially if combusted under 815 C, whilst the excluded minerals promoted the conversion of gehlenite to anorthite. Calcite in Shenhua coal decomposed into calcium oxide and partially transformed into calcium sulfate under 815 C, and formed gehlenite and anorthite under 1,050 C. Calcite and other HCl-dissolved minerals in Shenhua coal were responsible mainly for the characteristic that the clay minerals in Shenhua coal hardly became mullite during combustion.

  16. Chemically sulfated natural galactomannans with specific antiviral and anticoagulant activities.

    Science.gov (United States)

    Muschin, Tegshi; Budragchaa, Davaanyam; Kanamoto, Taisei; Nakashima, Hideki; Ichiyama, Koji; Yamamoto, Naoki; Shuqin, Han; Yoshida, Takashi

    2016-08-01

    Naturally occurring galactomannans were sulfated to give sulfated galactomannans with degrees of substitution of 0.7-1.4 per sugar unit and molecular weights of M¯n=0.6×10(4)-2.4×10(4). Sulfated galactomannans were found to have specific biological activities in vitro such as anticoagulant, anti-HIV and anti-Dengue virus activities. The biological activities were compared with those of standard dextran and curdlan sulfates, which are polysaccharides with potent antiviral activity and low cytotoxicity. It was found that sulfated galactomannans had moderate to high anticoagulant activity, 13.4-36.6unit/mg, compared to that of dextran and curdlan sulfates, 22.7 and 10.0unit/mg, and high anti-HIV and anti-Dengue virus activities, 0.04-0.8μg/mL and 0.2-1.1μg/mL, compared to those curdlan sulfates, 0.1μg/mL, respectively. The cytotoxicity on MT-4 and LCC-MK2 cells was low. Surface plasmon resonance (SPR) of sulfated galactomannans revealed strong interaction with poly-l-lysine as a model compound of virus proteins, and suggested that the specific biological activities might originate in the electrostatic interaction of negatively charged sulfate groups of sulfated galactomannans and positively charged amino groups of surface proteins of viruses. These results suggest that sulfated galactomannans effectively prevented the infection of cells by viruses and the degree of substitution and molecular weights played important roles in the biological activities. PMID:27154517

  17. Sulfur and oxygen isotope studies of sulfate reduction

    Science.gov (United States)

    Farquhar, J.; Canfield, D. E.; Bao, H.; Masterson, A.; Johnston, D. T.; Wing, B. A.

    2007-12-01

    I will discuss insights into sulfur and oxygen isotope fractionations of dissimilatory sulfate reduction and specifically insight provided by experiments with natural populations of sulfate-reducing bacteria from Faellestrand, Denmark. The experiments yielded relatively large magnitude sulfur isotope fractionations for dissimilatory sulfate reduction (up to approximately 45 ‰ for 34S/32S), with higher δ18O accompanying higher δ34S, similar to that observed in previous studies. The seawater used in the experiments was spiked by addition of 17O-labelled water and the 17O content of residual sulfate was found to depend on the fraction of sulfate reduced in the experiments. The 17O data provides evidence for recycling of sulfur from metabolic intermediates and for an 18O/16O fractionation of ~25-30 ‰ for dissimilatory sulfate reduction, a magnitude that is consistent with isotopic exchange between a sulfite species and cell water. The molar ratio of oxygen exchange to sulfate reduction was found to be about 2.5. Using recent models of sulfur isotope fractionations we find that our combined sulfur and oxygen isotopic data places constraints on the proportion of sulfate recycled to the medium (78-96 %), the proportion of sulfur intermediate sulfite that was recycled by way of APS to sulfate and released back to the external sulfate pool (~70%) and also that a fraction of the sulfur intermediates between sulfite and sulfide were recycled to sulfate. These parameters can be constrained because of the independent information provided by δ18O, δ34S, 17O labels, and Δ33S.

  18. Melittin interaction with sulfated cell surface sugars.

    Science.gov (United States)

    Klocek, Gabriela; Seelig, Joachim

    2008-03-01

    Melittin is a 26-residue cationic peptide with cytolytic and antimicrobial properties. Studies on the action mechanism of melittin have focused almost exclusively on the membrane-perturbing properties of this peptide, investigating in detail the melittin-lipid interaction. Here, we report physical-chemical studies on an alternative mechanism by which melittin could interact with the cell membrane. As the outer surface of many cells is decorated with anionic (sulfated) glycosaminoglycans (GAGs), a strong Coulombic interaction between the two oppositely charged molecules can be envisaged. Indeed, the present study using isothermal titration calorimetry reveals a high affinity of melittin for several GAGs, that is, heparan sulfate (HS), dermatan sulfate, and heparin. The microscopic binding constant of melittin for HS is 2.4 x 10 (5) M (-1), the reaction enthalpy is Delta H melittin (0) = -1.50 kcal/mol, and the peptide-to-HS stoichiometry is approximately 11 at 10 mM Tris, 100 mM NaCl at pH 7.4 and 28 degrees C. Delta H melittin (0) is characterized by a molar heat capacity of Delta C P (0) = -227 cal mol (-1) K (-1). The large negative heat capacity change indicates that hydrophobic interactions must also be involved in the binding of melittin to HS. Circular dichroism spectroscopy demonstrates that the binding of the peptide to HS induces a conformational change to a predominantly alpha-helical structure. A model for the melittin-HS complex is presented. Melittin binding was compared with that of magainin 2 and nisin Z to HS. Magainin 2 is known for its antimicrobial properties, but it does not cause lysis of the eukaryotic cells. Nisin Z shows activity against various Gram-positive bacteria. Isothermal titration calorimetry demonstrates that magainin 2 and nisin Z do not bind to HS (5-50 degrees C, 10 mM Tris, and 100 mM NaCl at pH 7.4). PMID:18220363

  19. A radioimmunoassay for measurement of thyroxine sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, I.J.; Santini, F.; Hurd, R.E.; Chua Teco, G.N. (Univ. of California Center for the Health Sciences, Los Angeles (United States))

    1993-01-01

    A highly sensitive, specific, and reproducible RIA has been developed to measure T[sub 4] sulfate (T[sub 4]S) in ethanol extracts of serum. rT[sub 3] sulfate (rT[sub 3]S) cross-reacted 7.1%, and T[sub 3]S cross-reacted 0.59% in the RIA; T[sub 4], T[sub 3], rT[sub 3] and 3,3[prime]-diiodothyronine cross-reacted 0.004% or less. The recovery of nonradioactive T[sub 4]S added to serum averaged 95%. The detection threshold of the RIA was 18 pmol/L. The coefficient of variation averaged 6.9% within an assay and 12% between assays. T[sub 4]S was bound by T[sub 4]-binding globulin and albumin in serum. The free fraction of T[sub 4]S in four normal sera averaged 0.06% compared to a value of 0.03% for T[sub 4] (P < 0.001). The serum concentration of T[sub 4]S was (mean [+-] SE) 19 [+-] 1.2 pmol/L in normal subjects, 33 [+-] 10 in hyperthyroid patients with Graves disease, 42 [+-] 15 in hypothyroid patients, 34 [+-] 6.9 in patients with systematic nonthyroidal illnesses, 21 [+-] 4.3 in pregnant women at 15-40 weeks gestation, and 245 [+-] 26 in cord blood sera of newborns; the value in the newborn was significantly different from normal (P < 0.001). Administration of sodium ipodate (Oragrafin; 3 g, orally) to hyperthyroid patients was associated with a transient increase in serum T[sub 4]S. The T[sub 4]S content of the thyroid gland was less than 1/4000th that of T[sub 4]. We conclude that (1) T[sub 4]S is a normal component of human serum, and its levels are markedly increased in newborn serum and amniotic fluid; and (2) the sulfation pathway plays an important role in the metabolism of T[sub 4] in man. 28 refs., 4 figs., 2 tabs.

  20. [Calcium pyrophosphate dihydrate deposition disease].

    Science.gov (United States)

    Koitschev, C; Kaiserling, E; Koitschev, A

    2003-08-01

    Calcium pyrophosphate dihydrate deposition disease (CPPD) of the temporomandibular joint is rare. The disorder is characterized by the presence of crystal deposits within the affected joint. The deposition of crystals in adjacent soft tissue may lead to the formation of pseudotumors. This form of the disease is called tophaceous pseudogout and typically affects the temporomandibular joint. It is difficult to differentiate the disease, particularly from malignant tumors, on the clinical and radiographic findings alone. The diagnosis is based on histological identification of the calcium pyrophosphate crystals. We present an unusually advanced case of tophaceous pseudogout of the temporomandibular joint. The etiology, clinical and diagnostic criteria as well as treatment options are discussed on the basis of our own experience and a review of the literature. PMID:12942180

  1. Testosterone increases urinary calcium excretion and inhibits expression of renal calcium transport proteins

    DEFF Research Database (Denmark)

    Hsu, Yu-Juei; Dimke, Henrik Anthony; Schoeber, Joost P H;

    2010-01-01

    Although gender differences in the renal handling of calcium have been reported, the overall contribution of androgens to these differences remains uncertain. We determined here whether testosterone affects active renal calcium reabsorption by regulating calcium transport proteins. Male mice had...... higher urinary calcium excretion than female mice and their renal calcium transporters were expressed at a lower level. We also found that orchidectomized mice excreted less calcium in their urine than sham-operated control mice and that the hypocalciuria was normalized after testosterone replacement...... calcium transport. Thus, our study shows that gender differences in renal calcium handling are, in part, mediated by the inhibitory actions of androgens on TRPV5-mediated active renal calcium transport....

  2. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    Science.gov (United States)

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control. PMID:22325887

  3. Serum calcium in pulmonary tuberculosis

    OpenAIRE

    Subhash C. Sharma

    1981-01-01

    Serum calcium was studied serially in 94 patients with active pulmonary tuberculosis. An equal number of age- and sex-matched patients with chronic obstructive pulmonary disease were controls. Seventy patients in the study group were normocalcaemic and 10 were hypercalcaemic. These 10 were on a higher supplement of vitamin D than the 70 normocalcaemic patients. There was a positive correlation between the daily vitamin intake and the degree and duration of hypercalcaemia. None of the controls...

  4. Drying dichloromethane over calcium hydride

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of dichloromethane by a simple 10 step procedure. One can implement this protocol using common lab glass and lab equipment. First, dichloromethane is refluxed with calcium hydride to remove water. Then, dichloromethane is distilled to separate it from the byproducts of the reflux reaction. This procedure can be implemented in 1 day. ### Introduction In many instances i...

  5. CCN3 and calcium signaling

    Directory of Open Access Journals (Sweden)

    Li Chang Long

    2003-08-01

    Full Text Available Abstract The CCN family of genes consists presently of six members in human (CCN1-6 also known as Cyr61 (Cystein rich 61, CTGF (Connective Tissue Growth Factor, NOV (Nephroblastoma Overexpressed gene, WISP-1, 2 and 3 (Wnt-1 Induced Secreted Proteins. Results obtained over the past decade have indicated that CCN proteins are matricellular proteins, which are involved in the regulation of various cellular functions, such as proliferation, differentiation, survival, adhesion and migration. The CCN proteins have recently emerged as regulatory factors involved in both internal and external cell signaling. CCN3 was reported to physically interact with fibulin-1C, integrins, Notch and S100A4. Considering that, the conformation and biological activity of these proteins are dependent upon calcium binding, we hypothesized that CCN3 might be involved in signaling pathways mediated by calcium ions. In this article, we review the data showing that CCN3 regulates the levels of intracellular calcium and discuss potential models that may account for the biological effects of CCN3.

  6. 21 CFR 522.650 - Dihydrostreptomycin sulfate injection.

    Science.gov (United States)

    2010-04-01

    ...; and L. grippotyphosa. (3) Limitations. Administer by deep intramuscular injection only. Treatment... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Dihydrostreptomycin sulfate injection. 522.650... § 522.650 Dihydrostreptomycin sulfate injection. (a) Specifications. Each milliliter...

  7. 21 CFR 522.62 - Aminopentamide hydrogen sulfate injection.

    Science.gov (United States)

    2010-04-01

    ... subcutaneous or intramuscular injection every 8 to 12 hours, as follows: Weight of animal in pounds Dosage in... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aminopentamide hydrogen sulfate injection. 522.62... § 522.62 Aminopentamide hydrogen sulfate injection. (a) Chemical name....

  8. Sulfate was a trace constituent of Archean seawater

    DEFF Research Database (Denmark)

    Crowe, Sean Andrew; Paris, Guillaume; Katsev, Sergei;

    2014-01-01

    In the low-oxygen Archean world (>2400 million years ago), seawater sulfate concentrations were much lower than today, yet open questions frustrate the translation of modern measurements of sulfur isotope fractionations into estimates of Archean seawater sulfate concentrations. In the water column...

  9. Reductive and sorptive properties of sulfate green rust (GRSO4)

    DEFF Research Database (Denmark)

    Nedel, Sorin

    The Fe(II), Fe(III) hydroxide containing sulfate in its structure, called sulfate green rust (GRSO4), can effectively reduce and convert contaminants to less mobile and less toxic forms. However, the ability of GRSO4 to remove positively charged species from solution, via sorption, is very limited...

  10. Sulfation of ractopamine and salbutamol by the human cytosolic sulfotransferases

    Science.gov (United States)

    Ko, KyoungA; Kurogi, Katsuhisa; Davidson, Garrett; Liu, Ming-Yih; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2012-01-01

    Feed additives such as ractopamine and salbutamol are pharmacologically active compounds, acting primarily as β-adrenergic agonists. This study was designed to investigate whether the sulfation of ractopamine and salbutamol may occur under the metabolic conditions and to identify the human cytosolic sulfotransferases (SULTs) that are capable of sulfating two major feed additive compounds, ractopamine and salbutamol. A metabolic labelling study showed the generation and release of [35S]sulfated ractopamine and salbutamol by HepG2 human hepatoma cells labelled with [35S]sulfate in the presence of these two compounds. A systematic analysis using 11 purified human SULTs revealed SULT1A3 as the major SULT responsible for the sulfation of ractopamine and salbutamol. The pH dependence and kinetic parameters were analyzed. Moreover, the inhibitory effects of ractopamine and salbutamol on SULT1A3-mediated dopamine sulfation were investigated. Cytosol or S9 fractions of human lung, liver, kidney and small intestine were examined to verify the presence of ractopamine-/salbutamol-sulfating activity in vivo. Of the four human organs, the small intestine displayed the highest activity towards both compounds. Collectively, these results imply that the sulfation mediated by SULT1A3 may play an important role in the metabolism and detoxification of ractopamine and salbutamol. PMID:22763752

  11. Tandem mass spectrometry of heparan sulfate negative ions

    DEFF Research Database (Denmark)

    Shi, Xiaofeng; Huang, Yu; Mao, Yang;

    2012-01-01

    are protonated, deprotonated, and metal-adducted using density functional theory computations. The calculations showed that sulfate loss from a protonated site was much more facile than that from a deprotonated or metal-adducted site. Further, the loss of SO(3) from N-sulfate was energetically favored...

  12. Stable isotope ratio measurements in atmospheric sulfate studies

    International Nuclear Information System (INIS)

    The isotopic composition of atmospheric sulfate has been determined by a number of workers and the results interpreted in terms of contributing sources and mechanisms of origin. A correlation between the 18O enrichment of atmospheric water and airborne particulate sulfate has been observed. Laboratory preparations of sulfate made from sulfur dioxide by two sets of sequential reactions, hydrolysis followed by oxidation and oxidation followed by hydrolysis, yielded products of distinguishable oxygen-isotope composition. Oxygen isotopic analysis of simultaneously collected field samples of ambient sulfate, sulfur dioxide, and water vapor indicated seasonal trends for all of the major constituents of atmospheric sulfation processes. Some isotopic data were also obtained on precipitation and precipitation sulfates. Field results suggest that ambient sulfates collected in the area of Argonne correpond more closely in oxygen isotope composition to a sulfate molecule containing two oxygens originating from sulfur dioxide, one oxygen from air and one oxygen from condensed-phased atmospheric water, SO/sub s/O/sub s/O/sub cw/O2-/sub a/, than to the molecule SO/sub s/O/sub s/O/sub wv/O2/sub a/ in which one oxygen originates from vapor-phase atmospheric water

  13. Experimental sulfate amendment alters peatland bacterial community structure.

    Science.gov (United States)

    Strickman, R J S; Fulthorpe, R R; Coleman Wasik, J K; Engstrom, D R; Mitchell, C P J

    2016-10-01

    As part of a long-term, peatland-scale sulfate addition experiment, the impact of varying sulfate deposition on bacterial community responses was assessed using 16S tag encoded pyrosequencing. In three separate areas of the peatland, sulfate manipulations included an eight year quadrupling of atmospheric sulfate deposition (experimental), a 3-year recovery to background deposition following 5years of elevated deposition (recovery), and a control area. Peat concentrations of methylmercury (MeHg), a bioaccumulative neurotoxin, were measured, the production of which is attributable to a growing list of microorganisms, including many sulfate-reducing Deltaproteobacteria. The total bacterial and Deltaproteobacterial community structures in the experimental treatment differed significantly from those in the control and recovery treatments that were either indistinguishable or very similar to one another. Notably, the relatively rapid return (within three years) of bacterial community structure in the recovery treatment to a state similar to the control, demonstrates significant resilience of the peatland bacterial community to changes in atmospheric sulfate deposition. Changes in MeHg accumulation between sulfate treatments correlated with changes in the Deltaproteobacterial community, suggesting that sulfate may affect MeHg production through changes in the community structure of this group. PMID:27267720

  14. Novel Thermally Stable Poly (vinyl chloride) Composites for Sulfate Removal

    Science.gov (United States)

    BaCO3 dispersed PVC composites were prepared through a polymer re-precipitation method. The composites were tested for sulfate removal using rapid small scale column test (RSSCT) and found to significantly reduce sulfate concentration. The method was extended to synthe...

  15. Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration

    Science.gov (United States)

    Belle-Oudry, Deirdre

    2008-01-01

    The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

  16. IMPACT OF A PRIMARY SULFATE EMISSION SOURCE ON AIR QUALITY

    Science.gov (United States)

    A one-month study was carried out at an isolated oil-fired power plant in New York State to assess the impact of primary sulfate emissions on air quality. Emissions of total sulfate from the source varied from 22 kg/hr to 82 kg/hr per boiler with the sulfuric acid concentration a...

  17. Transmission spectra study of sulfate substituted potassium dihydrogen phosphate

    KAUST Repository

    LI, LIANG

    2013-04-18

    Potassium dihydrogen phosphate (KDP) crystals with different amounts of sulfate concentration were grown and the transmittance spectrum was studied. A crystal with high sulfate replacement density exhibits heavy absorption property in the ultraviolet region which confirms and agrees well with former results. © 2013 Astro Ltd.

  18. 21 CFR 524.1484a - Neomycin sulfate ophthalmic ointment.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Neomycin sulfate ophthalmic ointment. 524.1484a... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1484a Neomycin sulfate ophthalmic ointment. (a) Specifications. Each gram of the ointment...

  19. 21 CFR 524.1044c - Gentamicin sulfate ophthalmic ointment.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Gentamicin sulfate ophthalmic ointment. 524.1044c... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND TOPICAL DOSAGE FORM NEW ANIMAL DRUGS § 524.1044c Gentamicin sulfate ophthalmic ointment. (a) Specifications. Each gram of ointment...

  20. Combining sulfate electrowinning with chloride leaching

    Science.gov (United States)

    Fletcher, A. W.; Sudderth, R. B.; Olafson, S. M.

    1991-08-01

    Although the chloride leaching of copper sulfide concentrates has proved highly efficient, electrowinning from chloride solutions presents many difficulties, notably in cell design and the handling of the powder product. Sulfate electrowinning,on the other hand, continues to improve and has played a significant part in the widespread adoption of the solvent extraction-electrowinning process for copper recovery from low-grade ores. It has been found that the two steps can be combined by introducing a novel solvent extraction process after chloride leaching. This article presents the results of laboratory tests to prove the feasibility of this approach and discusses how it can be integrated into a commercially viable flow sheet.

  1. Structum (chondroitin sulfate in treatment of osteoarthritis

    Directory of Open Access Journals (Sweden)

    O J Varga

    2003-01-01

    Full Text Available Objective. To assess Structum (chondroitin sulfate efficacy in treatment of osteoarthritis in Republic of Karelia. Methods. 34 pts with osteoarthritis (mean disease duration 6,44±0,67 years were included. Functional Leken score (FLS, pain at rest and at walk on visual analog scale (VAS, pts nonsteroidal anti-inflammatory drugs (NSAID requirement (diclofenac daily requirement in mg, percent of pts refused NSAID treatment, achievement of clinically significant improvement (40% decrease of FLS and/or 50% decrease of NSAID requirement were regarded as variables for the evaluation of therapy efficacy. Results. Structum administration in pts with osteoarthritis provided reduction of FLS, pain at rest and at walk, NSAID requirement and in some cases allowed to withdraw of NSAID completely. Structum has good safety and is effective in doctor and pts opinion. Conclusion. Structum is an effective drug for treatment of osteoarthritis.

  2. Synthesis of selective inhibitors of heparan sulfate and chondroitin sulfate proteoglycan biosynthesis.

    Science.gov (United States)

    Mencio, Caitlin; Garud, Dinesh R; Kuberan, Balagurunathan; Koketsu, Mamoru

    2015-01-01

    Glycosaminoglycan (GAG) side chains of proteoglycans are involved in a wide variety of developmental and pathophysiological functions. Similar to a gene knockout, the ability to inhibit GAG biosynthesis would allow us to examine the function of endogenous GAG chains. However, ubiquitously and irreversibly knocking out all GAG biosynthesis would cause multiple effects making it difficult to attribute a specific biological role to a specific GAG structure in spatiotemporal manner. Reversible and selective inhibition of GAG biosynthesis would allow us to examine the importance of endogenous GAGs to specific cellular, tissue, or organ systems. In this chapter, we describe the chemical synthesis and biological evaluation of 4-deoxy-4-fluoro-xylosides as selective inhibitors of heparan sulfate and chondroitin/dermatan sulfate proteoglycan biosynthesis. PMID:25325945

  3. Preparation and characterization of a chemically sulfated cashew gum polysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Moura Neto, Erico de; Maciel, Jeanny da S.; Cunha, Pablyana L. R.; Paula, Regina Celia M. de; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza (Brazil)

    2011-09-15

    Cashew gum (CG) was sulfated in pyridine:formamide using chlorosulfonic acid as the reagent. Confirmation of sulfation was obtained by Fourier transform infrared (FTIR) spectroscopy through the presence of an asymmetrical S=O stretching vibration at 1259 cm{sup -1}. The degrees of substitution were 0.02, 0.24 and 0.88 determined from the sulfur percentage. 1D and 2D nuclear magnetic resonance (NMR) data showed that the sulfation occurred at primary carbons. An increase of at least 4% of the solution viscosity was observed due to sulfation. The thermal gravimetric curves (TGA) indicate that the derivatives are stable up to ca. 200 deg C. The sulfated CG is compared to carboxymethylated CG in order to verify the possibility of the use of the former in the preparation of polyelectrolyte complexes; the latter is already being used for this application. (author)

  4. Extraction of beryllium sulfate by a long chain amine

    International Nuclear Information System (INIS)

    The extraction of sulfuric acid in aqueous solution by a primary amine in benzene solution, 3-9 (diethyl) - 6-amino tri-decane (D.E.T. ) - i.e., with American nomenclature 1-3 (ethyl-pentyl) - 4-ethyl-octyl amine (E.P.O.) - has made it possible to calculate the formation constants of alkyl-ammonium sulfate and acid sulfate. The formula of the beryllium and alkyl-ammonium sulfate complex formed in benzene has next been determined, for various initial acidity of the aqueous solution. Lastly, evidence has been given of negatively charged complexes of beryllium and sulfate in aqueous solution, through the dependence of the aqueous sulfate ions concentration upon beryllium extraction. The formation constant of these anionic complexes has been evaluated. (author)

  5. The role of calcium in human aging.

    Science.gov (United States)

    Beto, Judith A

    2015-01-01

    Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance. PMID:25713787

  6. Rapid screening assay for calcium bioavailability studies

    International Nuclear Information System (INIS)

    Calcium bioavailability has been studied by numerous techniques. The authors report here the use of the gamma emitting isotope of calcium (47Ca) in a whole body retention assay system. In this system, calcium sources are administered by oral gavage and subsequent counts are determined and corrected for isotopic decay. Unlike iron and zinc retention curves, which exhibit a 2-3 day equilibration period, calcium reaches equilibration after 24 hours. Autoradiographic analysis of the femurs indicate that the newly absorbed calcium is rapidly distributed to the skeletal system. Moreover, the isotope is distributed along the entire bone. Comparisons of calcium bioavailability were made using intrinsic/extrinsic labeled milk from two species i.e. rat and goat as well as CaCO3. In addition, extrinsic labeled cow milk was examined. In the rat, the extrinsic labeled calcium from milk was better absorbed than the intrinsic calcium. This was not the case in goat milk or the calcium carbonate which exhibited no significant differences. Chromatographic analysis of the labeled milk indicates a difference in distribution of the 47Ca. From these data, the authors recommend the use of this assay system in calcium bioavailability studies. The labeling studies and comparisons indicate caution should be used, however, in labeling techniques and species milk comparison

  7. Role of protein sulfation in vasodilation induced by minoxidil sulfate, a K+ channel opener

    Energy Technology Data Exchange (ETDEWEB)

    Meisheri, K.D.; Oleynek, J.J.; Puddington, L. (Cardiovascular Diseases Research, Upjohn Laboratories, Upjohn Company, Kalamazoo, MI (United States))

    1991-09-01

    Evidence from contractile, radioisotope ion flux and electrophysiological studies suggest that minoxidil sulfate (MNXS) acts as a K+ channel opener in vascular smooth muscle. This study was designed to examine possible biochemical mechanisms by which MNXS exerts such an effect. Experiments performed in the isolated rabbit mesenteric artery (RMA) showed that MNXS, 5 microM, but not the parent compound minoxidil, was a potent vasodilator. Whereas the relaxant effects of an another K+ channel opener vasodilator, BRL-34915 (cromakalim), were removed by washing with physiological saline solution, the effects of MNXS persisted after repeated washout attempts. Furthermore, after an initial exposure of segments of intact RMA to (35S) MNXS, greater than 30% of the radiolabel was retained 2 hr after removal of the drug. In contrast, retention of radiolabel was not detected with either (3H)MNXS (label on the piperidine ring of MNXS) or (3H)minoxidil (each less than 3% after a 2-hr washout). These data suggested that the sulfate moiety from MNXS was closely associated with the vascular tissue. To determine if proteins were the acceptors of sulfate from MNXS, intact RMAs were incubated with (35S)MNXS, and then 35S-labeled proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analyzed by fluorography. Preferential labeling of a 116 kD protein was detected by 2 and 5 min of treatment. A 43 kD protein (resembling actin) also showed significant labeling. A similar profile of 35S-labeled proteins was observed in (35S) MNXS-treated A7r5 rat aortic smooth muscle cells, suggesting that the majority of proteins labeled by (35S)MNXS in intact RMA were components of smooth muscle cells.

  8. Fluorous-Tag Assisted Syntheses of Sulfated Keratan Sulfate Oligosaccharide Fragments.

    Science.gov (United States)

    Bhaduri, Sayantan; Pohl, Nicola L B

    2016-03-18

    The first block iteration strategy for iterative solution-phase synthesis of protected keratan sulfate (KS)-like fragments is reported. Obstacles in a strategy using galactose-glucosamine (Gal-GlcNAc) modules led to the discovery of a differentially protected GlcNAc-Gal module that could be used to synthesize KS-like fragments using a fluorous tag that maintained solubility in organic solvents for purification of all intermediates via fluorous solid-phase extraction. PMID:26958998

  9. STIM1 is a Calcium Sensor Specialized for Digital Signaling

    OpenAIRE

    Bird, Gary S.; Hwang, Sung-Yong; Smyth, Jeremy T.; Fukushima, Miwako; Boyles, Rebecca R.; Putney, James W.

    2009-01-01

    When cells are activated by calcium-mobilizing agonists at low, physiological concentrations, the resulting calcium signals generally take the form of repetitive regenerative discharges of stored calcium, termed calcium oscillations [1]. These intracellular calcium oscillations have long fascinated biologists as representing a mode of digitized intracellular signaling. Recent work has highlighted the role of calcium influx as an essential component of calcium oscillations [2]. This influx occ...

  10. A revised isotope fractionation model for dissimilatory sulfate reduction in sulfate reducing bacteria

    Science.gov (United States)

    Brunner, Benjamin; Bernasconi, Stefano M.

    2005-10-01

    Sulfur isotope fractionation during dissimilatory sulfate reduction has been conceptually described by the widely accepted Rees model as related to the stepwise reduction of sulfate to sulfide within the cells of bacteria. The magnitude of isotope fractionation is determined by the interplay between different reduction steps in a chain of reactions. Here we present a revision of Rees' model for bacterial sulfate reduction that includes revised fractionation factors for the sulfite-sulfide step and incorporates new forward and reverse steps in the reduction of sulfite to sulfide, as well as exchange of sulfide between the cell and ambient water. With this model we show that in contrast to the Rees model, isotope fractionations well in excess of -46‰ are possible. Therefore, some of the large sulfur isotope fractionations observed in nature can be explained without the need of alternate pathways involving the oxidative sulfur cycle. We use this model to predict that large fractionations should occur under hypersulfidic conditions and where electron acceptor concentrations are limiting.

  11. Low levels of H2S may replace sulfate as sulfur source in sulfate-deprived onion

    NARCIS (Netherlands)

    Durenkamp, Mark; De Kok, LJ

    2005-01-01

    Onion (Allium cepa L.) was exposed to low levels of H2S in order to investigate to what extent H2S could be used as a sulfur source for growth under sulfate-deprived conditions. Sulfate deprivation for a two-week period resulted in a decreased biomass production of the shoot, a subsequently decrease

  12. 21 CFR 524.154 - Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate ophthalmic ointment.

    Science.gov (United States)

    2010-04-01

    ...-polymyxin B sulfate ophthalmic ointment. 524.154 Section 524.154 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS OPHTHALMIC AND... sulfate ophthalmic ointment. (a) Sponsor. To firms identified in § 510.600(c) of this chapter as...

  13. Purification and partial characterization of a novel calcium-binding protein from Bacillus cereus T spores and inhibition of germination by calmodulin antagonists

    International Nuclear Information System (INIS)

    A novel calcium-binding protein has been purified from the dormant spores of Bacillus cereus T. B. cereus T spores were extensively washed, broken, and heated at 90 degree C for 2 min. Using calcium-dependent hydrophobic interaction chromatography plus DEAE-cellulose and hydroxylapatite columns, a single protein was obtained which possessed calcium-binding capacity and some characteristics of calmodulin. This heat-stable protein was retained by hydrophobic matrices or a calmodulin antagonist in a calcium-dependent manner. The crude spore extract displaced bovine brain calmodulin from its antibody in a radioimmunoassay and the immunoreactive specific activity of the partially purified fraction which eluted from phenyl-Sepharose was ca. 200-fold greater than the crude spore extract. Purity of this protein was verified by sodium dodecyl sulfate-polyarcylamide gel electrophoresis and reversed-phase HPLC. Calcium-binding ability was verified with a competitive calcium binding assay using Chelex-100 resin and 45Ca autoradiography. SDS-PAGE and amino acid composition indicated the molecular weight of the protein was 24-kDa. The effects of two calmodulin antagonists, trifluoperazine (TFP) and N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) on L-alanine-induced germination of Bacillus cereus T spores were examined by measuring commitment to germination, loss of heat resistance, release of calcium, decrease in optical density at 660 nm and phase-contrast microscopy

  14. Fortification of all-purpose wheat-flour tortillas with calcium lactate, calcium carbonate, or calcium citrate is acceptable.

    Science.gov (United States)

    Romanchik-Cerpovicz, Joelle E; McKemie, Rebecca J

    2007-03-01

    Fortification helps provide adequate nutrients for individuals not meeting daily needs. Foods may be fortified with calcium to assist individuals with lactose intolerance and others preferring not to consume traditional forms of dairy. This study examined the quality of all-purpose wheat-flour tortillas fortified with calcium lactate, calcium carbonate, or calcium citrate. These tortillas were compared to similarly prepared nonfortified flour tortillas (control) and commercial nonfortified flour tortillas. Calcium-fortified tortillas contained 114 mg elemental calcium per standard serving (48 g tortilla), an 8.6-fold increase compared to nonfortified tortillas. Moisture contents and rollabilities of all tortillas were similar. Consumers (N=87) evaluated each tortilla in duplicate using a hedonic scale and reported liking the appearance, texture, flavor, aftertaste, and overall acceptability of all tortillas. However, the appearance of control tortillas was preferred over commercial tortillas (Ptortillas or those fortified with calcium carbonate was preferred over the control (Ptortillas, suggesting that appearance and aftertaste may not influence willingness to purchase. Overall, this study shows that fortification of flour tortillas with various forms of calcium is a feasible alternative calcium source. PMID:17324671

  15. Sulfated polyanions block Chlamydia trachomatis infection of cervix-derived human epithelia.

    OpenAIRE

    Zaretzky, F R; Pearce-Pratt, R; Phillips, D M

    1995-01-01

    Using a cell line derived from the human cervix and a rapid fluorescence cytotoxicity assay, we have shown that Chlamydia trachomatis infection can be blocked by certain sulfated polysaccharides (carrageenan, pentosan polysulfate, fucoidan, and dextran sulfate) and glycosaminoglycans (heparin, heparan sulfate, and dermatan sulfate) but not by other glycosaminoglycans (chondroitin sulfate A or C, keratan sulfate, and hyaluronic acid). The most negatively charged molecules are the most effectiv...

  16. Osmotic Pressure of Aqueous Chondroitin Sulfate Solution: A Molecular Modeling Investigation

    OpenAIRE

    Bathe, Mark; Rutledge, Gregory C.; Grodzinsky, Alan J.; TIDOR, BRUCE

    2005-01-01

    The osmotic pressure of chondroitin sulfate (CS) solution in contact with an aqueous 1:1 salt reservoir of fixed ionic strength is studied using a recently developed coarse-grained molecular model. The effects of sulfation type (4- vs. 6-sulfation), sulfation pattern (statistical distribution of sulfate groups along a chain), ionic strength, CS intrinsic stiffness, and steric interactions on CS osmotic pressure are investigated. At physiological ionic strength (0.15 M NaCl), the sulfation typ...

  17. Development of a rapid method for simultaneous separation of hyaluronic acid, chondroitin sulfate, dermatan sulfate and heparin by capillary electrophoresis.

    Science.gov (United States)

    Zhao, Ting; Song, Xinlei; Tan, Xiaoqing; Xu, Linghua; Yu, Mingxiu; Wang, Siyi; Liu, Xiumei; Wang, Fengshan

    2016-05-01

    This study reports the use of diethylenetriamine as background electrolyte for the simultaneous separation of hyaluronan acid, chondroitin sulfate, dermatan sulfate and heparin. The analytes were baseline separated by using an uncoated fused silica capillary at 37°C with a run time of 23min. The migration order, with hyaluronan acid at first and heparin at last, was related to the sulfation degree. The effect of salt concentration on resolution and migration order was also investigated. The developed method was applied to the simultaneous determination of hyaluronan acid and chondroitin sulfate in mouse plasma. Interferences in plasma were removed by protein precipitation and glycosaminoglycans were further purified by ethanol precipitation. The method was validated over the concentration range from 50 to 600μg/mL for hyaluronan acid and 500 to 6000μg/mL for chondroitin sulfate in mouse plasma. Results from assay validations showed that the method was selective and robust. PMID:26877013

  18. Sulfur Cycling Mediates Calcium Carbonate Geochemistry in Modern Marine Stromatolites

    Science.gov (United States)

    Visscher, P. T.; Hoeft, S. E.; Bebout, B. M.; Reid, R. P.

    2004-01-01

    Modem marine stromatolites forming in Highborne Cay, Exumas (Bahamas), contain microbial mats dominated by Schizothrix. Although saturating concentrations of Ca2+ and CO32- exist, microbes mediate CaCO3 precipitation. Cyanobacterial photosynthesis in these stromatolites aids calcium carbonate precipitation by removal of HS+ through CO2 use. Photorespiration and exopolymer production predominantly by oxygenic phototrophs fuel heterotrophic activity: aerobic respiration (approximately 60 umol/sq cm.h) and sulfate reduction (SR; 1.2 umol SO42-/sq cm.h) are the dominant C- consuming processes. Aerobic microbial respiration and the combination of SR and H2S oxidation both facilitate CaCO3 dissolution through H+ production. Aerobic respiration consumes much more C on an hourly basis, but duel fluctuating O2 and H2 depth profiles indicate that overall, SR consumes only slightly less (0.2-0.5) of the primary production. Moreover, due to low O2 concentrations when SR rates are peaking, reoxidation of the H2S formed is incomplete: both thiosulfate and polythionates are formed. The process of complete H2S oxidation yields H+. However, due to a low O2 concentration late in the day and relatively high O2 concentrations early in the following morning, a two-stage oxidation takes place: first, polythionates are formed from H2S, creating alkalinity which coincides with CaCO3 precipitation; secondly, oxidation of polythionates to sulfate yields acidity, resulting in dissolution, etc. Vertical profiles confirmed that the pH peaked late in the afternoon (greater than 8.8) and had the lowest values (less than 7.4) early in the morning. Thus, the effect of this S-cycling through alkalinity production, followed by acidification during H2S oxidation, results in a six times stronger fluctuation in acidity than photosynthesis plus aerobic respiration accomplish. This implies that anaerobic processes play a pivotal role in stromatolite formation.

  19. Application of Box-Behnken design to prepare gentamicin-loaded calcium carbonate nanoparticles.

    Science.gov (United States)

    Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

    2016-09-01

    The aim of this research was to prepare and optimize calcium carbonate (CaCO3) nanoparticles as carriers for gentamicin sulfate. A chemical precipitation method was used to prepare the gentamicin sulfate-loaded CaCO3 nanoparticles. A 3-factor, 3-level Box-Behnken design was used for the optimization procedure, with the molar ratio of CaCl2: Na2CO3 (X1), the concentration of drug (X2), and the speed of homogenization (X3) as the independent variables. The particle size and entrapment efficiency were considered as response variables. Mathematical equations and response surface plots were used, along with the counter plots, to relate the dependent and independent variables. The results indicated that the speed of homogenization was the main variable contributing to particle size and entrapment efficiency. The combined effect of all three independent variables was also evaluated. Using the response optimization design, the optimized Xl-X3 levels were predicted. An optimized formulation was then prepared according to these levels, resulting in a particle size of 80.23 nm and an entrapment efficiency of 30.80%. It was concluded that the chemical precipitation technique, together with the Box-Behnken experimental design methodology, could be successfully used to optimize the formulation of drug-incorporated calcium carbonate nanoparticles. PMID:25950955

  20. Characterizing the influence of anthropogenic emissions and transport variability on sulfate aerosol concentrations at Mauna Loa Observatory

    Science.gov (United States)

    Potter, Lauren E.

    Sulfate aerosol in the atmosphere has substantial impacts on human health and environmental quality. Most notably, atmospheric sulfate has the potential to modify the earth's climate system through both direct and indirect radiative forcing mechanisms (Meehl et al., 2007). Emissions of sulfur dioxide, the primary precursor of sulfate aerosol, are now globally dominated by anthropogenic sources as a result of widespread fossil fuel combustion. Economic development in Asian countries since 1990 has contributed considerably to atmospheric sulfur loading, particularly China, which currently emits approximately 1/3 of global anthropogenic SO2 (Klimont et al., 2013). Observational and modeling studies have confirmed that anthropogenic pollutants from Asian sources can be transported long distances with important implications for future air quality and global climate change. Located in the remote Pacific Ocean (19.54°N, 155.58°W) at an elevation of 3.4 kilometers above sea level, Mauna Loa Observatory (MLO) is an ideal measurement site for ground-based, free tropospheric observations and is well situated to experience influence from springtime Asian outflow. This study makes use of a 14-year data set of aerosol ionic composition, obtained at MLO by the University of Hawaii at Manoa. Daily filter samples of total aerosol concentrations were made during nighttime downslope (free-tropospheric) transport conditions, from 1995 to 2008, and were analyzed for aerosol-phase concentrations of the following species: nitrate (NO3-), sulfate (SO42-), methanesulfonate (MSA), chloride (Cl-), oxalate, sodium (Na+), ammonium (NH 4+), potassium (K+), magnesium (Mg 2+), and calcium (Ca2+). An understanding of the factors controlling seasonal and interannual variations in aerosol speciation and concentrations at this site is complicated by the relatively short lifetimes of aerosols, compared with greenhouse gases which have also been sampled over long time periods at MLO. Aerosol filter